ferent eee , ‘ sit fl : REPORT OF THE PIP TY -SixXTe « MERTING OF THE BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE; HELD AT BIRMINGHAM IN SEPTEMBER 1886. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1887. Office of the Association: 22 AtpEeMARLE Street, Lonpoy, W. PRINTED BY SPOTTISWOODE AND CO., NEW-STREET SQUARI — LONDON —~ CONTENTS, —— Page Oxsxcts and Rules of the Association ...........c.c.seceeesescnscsseseeeseesseees XXvil Places and Times of Meeting and Officers from commencement ............... XXKV Presidents and Secretaries of the Sections of the Association from com- BPE MNCOMMOTIG MA ich « ans dc o.snt he acloiidole dip ve ein watts ane te alatlsuielsapiic sale da athiadirs agveit xiii MERE IER Sco 35 nx ses axe pad she 0) «nah »Epgan saxepmeenngeseathpegaienuaeuge lvii umrmmmes GO tHe Operative OLASSOS 2... ..cc.sconsasccrpocssoug roascnstnmssectomeacecs Ix Officers of Sectional Committees present at the Birmingham Meeting ...... lxi MIE OMECOLTL gh cues. suis cesente devacsecstaracees ireustdsnsess ace Agana Ixiii Table showing the Attendance and Receipts at the Annual Meetings ...... lxiv Steers OOUNCH PTSSE“S7 c..s.csdsstcencacessueedcs even ovevoevewacvaceeenat eee lxvi Report of the Council to the General Committee ...........ssecsecsseneceeeeeees Ixvii Recommendations adopted by the General Committee for Additional mzeports and Researches in Science ...........00.yesscvsseesevseanscaivesenedetoes lxx Synopsis of Grants of Money .........s-csecssessreeeeeeons KS ayonscpeacee ich taee ses Ixxix pices Or Meeting in 1887 and 1888 ........ccsscensessssssesccsensacsvsceress scenes Ixxx General Statement of Sums which have been paid on account of Grants ermB (let NiTe MITE POSGS 2. teeeeeneeee 535 a7.) uel Calorunetry.. (BysB. . Diwarrn,, 1. OS.) 0... .scles0-0 200 seen ee eee rene 536 18. On Secular Experiments in Glasgow on the Elasticity of Wires. By Jeers OTTO MIEN MVicAcs Hokus). Woccctece.., =. ccsedesusectcsses«chs-s- een amen 537 MATHEMATICAL SuB-SECTION. . Report of the Committee for Calculating Tables of the Fundamental invariants Of Algebraic eb OTM. coc ssi ecucses _s.tisa uno] OM RS he ese andees ops ede asad neneae canna aEeSeHen errr cectondenad 582 . On the Action of Drinking-water on Lead. By Dr. C. Mrymorr Trpy ... 588 . Micro-organisms in Drinking-water. By Professor Opiine, F.R.S.......... 583 MONDAY, SEPTEMBER 6. . Report of the Committee appointed to investigate the Influence of the Silent Discharge of Electricity on Oxygen and other Gases ...........00.+0+ 583 . On the Preservation of Gases over Mercury. By Haroxp B. Drxon, Ne BOERS: shechccss Aacasstasseacsassbeccnssonveveserecndscsveduatdnsnbws deseds@eanhd 583 On the Methods of Chemical Fractionation. By Wu1L1am CrooKes, Fe se OV EO wniechasinees 2st ee ave scereesereenncenseneanesnnmann asvimneaqebtecses 583 . On the Fractionation of Yttria. By Wrii1am Crookes, F.R.S., V.P.C.S. 586 . On the Colour of the Oxides of Cerium and its Atomic Weight. By H. FROBINGON, McA. .....ccccscocseccnccsscecesceccescscsscceeccsceserscesssecseceseaesosee 591 . On the Determination of the Constitution of Carbon Compounds from Thermo-chemical Data. By Professor ARMSTRONG, F.R.S. ..........cccee eee 591 . On the relative Stability of the Camphene Hydrochlorides C,,H,,Cl ob- tained from Turpentine and Camphene respectively. By Ernest F. BHSESHA BID cn catienctdce ace toce cs sseecc tenses stcievcederds deda.esaicns stliblens ti mnetee de Gale saicbys 591 . On Derivatives of Tolidin and the Azotolidin Dyes. By R. F. Rurray, oleh lid oA liao x ae NP en SD) |, | 591 TUESDAY, SEPTEMBER 7. . On the Treatment of Phosphoric Crude Iron in Open-hearth Furnaces. By J. W. WALIILES .........scecceseecnssaseensenccececasscsceaesscnsscessacenscanseces 592 2. On the Basic Bessemer Process in South Staffordshire. By W. HUTCHINSON. ........... AP onteecete patcsasen etonseettes eee vedi deict Sasemaectaeseeaere es 593 3. On the Production of Soft Steel in a new type of Fixed Converter. By prea Glas ED A TTOIN shia eiptiawfa «ca haell dea cneo able ee eunnrine smote “mbit Meeme een accra 593 4, The Influence of Remelting on the Properties of Cast Iron. By THomas UNTER, Bi acertce Bene ace Sandee: toeoa? cdcecs escheer Qaodachoee steer sc aeeae. ca ne crear 594 5, Silicon in Cast Iron. By THOMAS TURNER.........0.c..ceeesseaeees saciieeaudaet 595 6. The Influence of Silicon on the Properties of Iron and Steel. By Tomas PIER assteccetsie srsci gasses seems some staasovasdsinc as acpeeutea seine desoackpiins dtapaereete 597 7. On the Estimation of Carbon in Iron and Steel. By Tuomas TuRNER ... 597 WEDNESDAY, SEPTEMBER 8. 1. Report of the Committee on Isomeric Naphthalene Derivatives ............ 598 . Report of the Committee for preparing a new series of Wave-length Tables of the Spectra of the Elements ..............:cssseeseecsecsscereeseeesenees 598 . On the Chemistry of Estuary Water. By Huen Roserr Mitt, D.Sc., MORN BUEN eet e, FE oh Co cetaes co ctrinakes ccaetene oct 598 . The Essential Oils: a Study in Optical Chemistry. By Dr. J. H. ISPD STONE when Sistavadacachetssch ssedeses: skemdendé eteoend escoadap dees scsi leesscsnas 599 XiV CONTENTS. Page 5. An Apparatus for maintaining Constant Temperatures up to 500°. By Ges BATURY DSc, MPD Dir eantacessscceocestets ree ntteesececceaes cossceeeenee 599: 6. On a new Apparatus for readily determining the Calorimetric Value of Fuel or Organic Compounds by Direct Combustion in Oxygen. By AV AUT ATTA MUOMSON, Ubu ISi Lis -sasiesss ses ode siocsiveetoaneses mane cee ance cesta 599: 7. On Some Decompositions of Benzoic Acid. By Professor Optine, F.R.S. 599 8. The Crystalline Structure of Iron Meteorites. By Dr. O. W. Hunrine- SUG M MM nee acmiae dace cave sasee ecaeeon t Veioaaciaie opiycore ds emetic eines ncae eee aaeeas 658 10. On the Influence of Axial Rotation of the Earth on the Interior of its (Wrists yr OF NJ GUNN, (EGS. . cncsecdecsccrssoscosepeceeacss costs aseraemeeteemnas 660 GeroLocy Sus-Srcrion. 1. Notes on some of the Problems now being investigated by the Officers of the Geological Survey in the North of Ireland, chiefly i in Co. Donegal. By Professor E. FG Hat, 12.1: BAe. Sen tizs o> - ovinue cove ooh cne see oeidaclani dasa 660 . Notes on the Crystalline Schists of Ireland. By C. Oattaway, D.S8c., IMIDE ES GE tic seis cnise'sinn ds aisice Acido niw stole 's« onle baw nels one Ola ia)# lacs’ nah Staaten 661 . The Ordovician Rocks of Shropshire. By Professor C. Lapworru, LL.D., IE Giriintacweiaes caviatds © odes dslatenlc seek. ticle onesie ncusaeeus adeciene sea Gace ats aee eae near 661 . On the Silurian Rocks of North Wales. By Professor T. M‘Kunny Huenss, M.A., F.G.S........6...c00000 Stile 4 obiniddGnice.- 40is teh Slade oer ate gee eee 663 . Notes on some Sections in the Arenig Series of North Wales and the Lake District. By Professor T. M‘Kenny Hueuss, M.A., F.G.S. ............00 663 . On the Lower Paleozoic Rocks near Settle. By J. E. Marr, M.A., IBEGEAS ak « cals sn deice'sle coRee no aeenwactaes suactodes aoecdcmsasecacess eat ske ace cenmenes 667 5. On the Metamorphosis of the Ligmard Gabbros. By J. J. H. Teatt, M.A., EG IGE aocencee rae octce ade = ahs decevameeeceeietace tebe Dee cams ee ses ots. c 2 sas 668 6. Introduction to the Monian System of Rocks. By Professor J. F. Brake, (0s SE oT O08 PaaS SE 669 CONTENTS. XVli Page . On the Igneous Rocks of Llyn Padarn, Yr Hifl,and Boduan. By Pro- PES a Crier ees ES GATE IM AY, GES: oc onceceae cocatev SMO Cd sveeecanesascasnsdesladeess 669 . On an Accurate and Rapid Method of Estimating the Silica in Igneous Wrens DEL, ELAVEH: 52 sachs. atccasaovsexacd'ss Cuncdss yess eiaatptevenedeseeseaas 670 9. On a new Form of Clinometer. By J. Hopxinson, F.L.S., F.G.S. .......... 670 aeem@onerenions.. By EH. B. STOCKS ..4.sisessacctasnoancesnsacnecaseanasancieonchs 670 11. On a Scrobicularia Bed, containing Human Bones, at Newton Abbot, Devonshire. By W. PENGELLY, BOTS Sey Vl NG ends oot cxanetavacdatenscnsctaestey 670 GeoLocy Sus-Sxction. 1. The Corndon Laccolites. By W. W. Warts, M.A., F.GS.......cc.cceseees 670 2. Fourth Report on the Fossil Phyllopoda of the Paleozoic Rocks............ 671 3. On the Discovery of Diprotodon Australis in Tropical Western Australia (Kimberley District). By Epwarp T. Harpmay, F.R.G.S.1........ . 671 4. Twelfth Report on the Circulation of Underground Waters...............0+6 672 5. On the Stratigraphical Position of the Salt-Measures of South Durham. iy eterofessor G27 Ay" LmBouR; MuA B.GiS. 2s. cecccvere;vecsennececcuseucuecsees 673 6. On the Carboniferous Limestone of the North of Flintshire. By G. H. REI OW Oi Lat twa asides dad cag ssc velectals Me ata eels oslees aidan oe oileluaine cue dadavetacas 673 7. On the Classification of the Carboniferous Limestone Series: North- umbrian Type. By Hueu Mitier, F.R.S.E., F.G.S. oo... ee sceecesee eee 674 8. The Culm Measures of Devonshire. By W. A. E. Ussumr, F.G.S......... 676 9, Denudation and Deposition by the Agency of Waves experimentally con- ied emey eAGele. CENT MGs.) «ccscescasnessos soscecccns uossegeastaptestee ss 676 10. Third Report on the Rate of Erosion of the Sea Coasts of England and en ee acs n nes, Sacecnowcnartqanocpivos cass sanbon? ono enveccpssaupnct 4-Seeh 677 11. On Deposits of Diatomite in Skye. By W. Ivison Macapam, F.C.S., and MRT ICANT VY ITSON, Ei: GiSececccecscattaccsecsscrasetcs coreseccccedcasswecckeaeees 678 Section D.—BIOLOGY. THURSDAY, SEPTEMBER 2. Address by Wittram Carruriers, Pres.L.S., F.R.S., F.G.S., President of il: 2 3. 4 EIEIO goceate taco salsa dn tusce oc clssnig jaecessensvsts'ecwanssacsccscos.temat tee 679 Report of the Committee for arranging for the Occupation of a Table at Bae Zoolorical Station at Naples: <..:........cecescucanserceseseusveqasages ducsuste 685 . Report of the Committee for continuing the Researches on Food-Fishes and Invertebrates at the St. Andrews Marine Woaboratory® <22.c-20.cee.0s-0 685 On the Value of the ‘Type System’ in the Teaching of Botany. By Pro- MESO AVINAY’ DATFOUR, PARAGs cq: cnctoctt cestceetcancn decodes cacccccsendanedteoes 685 . Remarks on Physiological Selection, an Additional Suggestion on the Origin of Species, by G. J. Romanes, F.R.S. By Henry SEEBoHM, aM Soi a a nn cbnnan shes ih's seca F cast awk « sspeataceteae Siatecadus daqhFontaccadhaers 685 . On Provincial Museums, their Work and Value. By F. T. Morr, F. JETS CORB CORRARG Ai Sines ie Ming te eB oe 59.9 ar Ra 686 FRIDAY, SEPTEMBER 3. . On some Points in the Development of Monotremes. By W. H. Catp- Bare ts emuemnncess eeeteadcssstcectetecttacrestaess reece tcesctecteae ros tementeetcertens 686 E os the Morphology of the Mammalian Coracoid. By Professor Howzs, F.L. eam te eee eae Sh nce UNSERE bad bodue cenabncstcees sess eaueaueeeeet hla) teres 686 . On Rudimentary Structures relating to the Human Coracoid Process, Pee ratcrdor, MANALISTER, FES, |. ccssesicoacssaaanscdihMabiesnankass aay "Aiea 687 1886. a XVili CONTENTS. Sus-Section PHysioLoey. UASCHsEION on Cerebral MOcalSATION «.arccessccse oceeene precede sees marmee apes tan 687 _— . On the Connection between Molecular Structure and Biological Action. By PAs DEAK E, MCT), Baie, EO Mon ca caenac saeuaecsnr dsc cnearapneseemeest 687 . Supplement to the Paper ‘ On the Gaines and Results of assumed Cycloidal Rotation in Arterial Red Dises.’ By Surg.-Major R. W. WooLtcomse... 687 SATURDAY, SEPTEMBER 4. feeheport on the Mieration, of¢birds tir. cs2..t0-2.5b)-- ceocs>-orsecdos>ncyemmeltcriat 688 2, Report of the Committee for promoting the Establishment of a Marine Biolocical Station at Granton dy: epeeacssscacesccgs cased es ac yce lot eve useaeace 688 3. Resort on the Record of Zoological Literature .........s00..sceeeeseeeceeeenees 688 4. Report of the Committee for ee ae the Mechanism of the Secretion GHWUPING, .ry.0c3h tera one eae eeee eee 696 10. Notes on Dredging off South-West of Ireland. By Professor Happon ... 696 11. Points in the Development of the Pectoral Fin and Girdle in Teleosteans. oy DWARD EL, PRINCE 52045 casites cnavsavas dbscen te gebtecheskhaencte wiacetth ten Ge 697 CONTENTS. xix Page 12. Some Remarks on the Egg-Membranes of Osseous Fishes. By Ropert SOMME SEU. PRISE, oo. 535% sanens snnace onde ES81s Mach < dol hl cnnmersadbad& 698 TUESDAY, SEPTEMBER 7. 1, On Humboldtia laurifolia as a Myrinekophilous Plant. By Professor F. O. Re 22g cn wie crm acres Te npaage oe RE oo SEs us fac chs th ns Reade Alina ecb 699 2. On Positively Geotropic Shoots in Cordyline australis. By Professor F. O. MN a oat evs epee ste daivuiie dun dicing hfrcsctadsxeeress Repairer dee race rt 699 3. Note on Apospores in Polystichum angulare, var. pulcherrimum. By Pro- Remeetet, 0). SO WEE:. SF 38% 0 21 bao) Oss PE cae teraas (2 éincieniactevhs ss coacvoy 700 4, On the Formation and Escape of the Zoospores in Saprolegnize. By Pro- OS TT LES) ARERR AS eS AS bse Ra A eS a 700 5. On the Germination of the Spores of Phytophthora infestans. By Pro- Seat MARSA WARD, MOA, ..00.sc00seesccecu sees souecyhumatiiceatt Tidy desigdeties 700 6. Two Fungous Diseases of Plants. By W. B. Grovn, B.A. .......cc00c0ec00e 700 7. Preliminary Notes on’ the Autumnal Fall of Leaves. By Professor W. MP ERAOU Go A.B Lathes .csasvesiny venscedsessianssnvanticcboch oc UM aAte ea 700 » Onan Apparatus for Determining the Rate of Transpiration. By Pro- fessor). “Hrrrousn, M.A or BULLS, 1 scsivs de snsnenss iach sniccvadth is Tiaeliveneoutes 701 . On the Cultivation of Beggiatoa alba. By Professor W. Hitiuovss, M.A., Ny et dich «Sais Me nas of lonlen Bashan chs “poh anzpadd>dowsohateksadened 701 . On Heterangium Tilioides. By Professor W. CO. Wixtramson, LL.D., E.R.S. MEIER IEAsita0 ai ptbseae ase tn. cation sis Ideas d8¥2 824 (2) The Drainage of the Tipton District. By E. Tprry ..............5 824 (3) The Drainage of the Old Hill District. By W. B. Cottts......... 825 Section H.—ANTHROPOLOGY. THURSDAY, SEPTEMBER 2. Address by Sir GzorcE Campsett, K.C.S.1., M.P., D.C.L., F.R.GS., President of tho Section \. .ciacascsantaaastycecessoceacnssseitecssthodssaeaeeenee 826 FRIDAY, SEPTEMBER 3. 1. On the Native Tribes of the Egyptian Sudan. By Sir Coartes W1tson, TIGFORIE HS SSIES) Cosae a aecsoo pene cone cae noe a eAnaIp SCC PROCOnRECOCPAAEenarmCrnes los: 833 2, On the Dutch in South Africa. By Miss F. 8. ALTIOPT.............00c00008 834 8. On the Celtic and Germanic Designs on Runic Crosses, By Professor BoyD Awan, MEAL SB UIEGS,, ES A. nsiceps soon ceasing Seesensnacksacheeine 834 4, Notes on Natives of the Kimberley District, Western Australia. By IFDWARD Ly AR D MAIN, HCE, GS.L.. :.s50-sseasesecaesseteemceeverndeacdenes sieenmae 835 10. CONTENTS. XXV Page . Observations on Four Crania, from Kimberley, West Australia (Mr. Hardman’s Collection). By P. S. AsranamM, M.A., M.D., B.Sc., EPEC a le recepas- cout 00s ace satoos docs tencerescstaccceavsseseunceseeertescerersesesveness . The Scientific Prevention of Consumption. By G. W. HAMBLETON...... . Dragon Sacrifices at the Vernal Equinox. By Gzorez Sr. Crarr, F.G.S. MONDAY, SEPTEMBER 6. ' ate of Pre-glacial Man in North Wales. By Henry Hicks, M.D., -R.S. PTI See OCePEOETOR TT OTOOOErrrerrrrrrrrerrr ree ee . On the recent Exploration of Gop Cairn and Cave. By Professor Boyp Dawrtns, M.A., F.R.S., FSA. .....cccecceceeseeeeeeeneeeeneeseeseeneens . On the recent Exploration of Bowls’s Barrow. By W. CUNNINGTON ... . On Crania and other Bones, from Bowls’s Barrow, in Wiltshire. By J.G. GARSON, M.D. .............cecsccrencscccscscecccccsccccccsccccnssssceseescccceseneeces . On a Scrobicularia Bed containing Human Bones, at Newton Abbot, Devonshire. By W. PENGELLY, F.R.S., F.G.S. .....cceeeeeeeseeeeeeresee ees . . Papuans and Polynesians. By the Rev. G. Brown, F.R.G.S, ........++ TUESDAY, SEPTEMBER 7. . What isan Aryan? By Sir Grorer CaMPBELL, K.C.S.1.........02seeeeee . The Influence of Canadian Climate on European Races. By Professor W. H. Hineston, M.D., D.C.Li.........cccccecescseceececesereecesesepensoseesons . Traces of Ancient Sun Worship in Hampshire and Wiltshire, By T. W. PERE esa en Stada'csese sees oeimesetave ste tataccccas dapotescssacasedestactoneram . The Life History of a Savage. By the Rev. Grorcr Brown, F.R.G.S. . Note on Photographs of Mummies of Ancient Egyptian Kings, recently unrolled at Boulak. By Sir J. Wrzt1am Dawson, C.M.G., F.B.S. ... . On the Anatomy of Aboriginal Australians. By Professor A. MVR GANEISTTER AE Sa0 Poet swscosades vs dan-eidadeseaesdcpsessasdseccusevsssaneecsdsenns . Notes on a Tau Cross on the Badge of a Medicine Man of the Queen Charlotte Islands. By R. G. HALIBURTON. .......cscesecseeereesseeeeneseenees . Remains of Prehistoric Man in Manitoba, By Cuartrs N. BExt, BEG aii coon. daar. cacees ssiaerasee cen ddncsecewens stresses sscccserpast-assenesnce . Report of the Committee for investigating and publishing reports on the physical characters, languages, and industrial and social condition of the North-western Tribes of the Dominion of Canada .......00.....sssseeseeeee Report of the Committee for investigating the Prehistoric Race in the UE ESLE TRIER EV 2 05 Sa oenpostegoce Suaocc ce teaoscc cose conod 36 Searednoctneacoed Senco Apprnpix.—Second Report of the Committee, consisting of Messrs. R. B. GranruHam, OC, E. De Rance, J. B. RepMan, W. Toprey, W. WHITAKER, and J. W. Woopatt, Major-General Sir A. CLarxg, Sir J. N. Doverass, Admiral Sir E. Ommanney, Capt. Sir G. S. Narzs, Capt. J. Parsons, Professor J. PRestwicH, Capt. W. J. L. Warton, and Messrs. E. Easton, J.S. Vatentine, and L, F. Vernon Harcourt, appointed for the pur- pose of inquiring into the Rate of Erosion of the Sea-coasts of England and Wales, and the Influence of the Artificial Abstraction of Shingle or other Material in that Action. (C. E. Dr Rancr and W. Top.ey, Secretaries.) The Report edited by W. TOPLEY ...........cccccseceseeeeeeees REET ry Oe at Peete GE en ty RR LOREEN US a A pdsenceeccese 836 837 838 XXV1 LIST OF PLATES. LIST. OF PLATES. PLATES I., Il., anp IIL. Mlustrating the Report of the Committee Pe Considering the best means of Com- paring and Reducing Magnetic Observations. PLATES IV. ann V. Illustrating the Report of the Committee for Constructing and Issuing Practical Standards for use in Electrical Measurements. PLATE VI. Illustrating the Report of the Committee for the Reduction and Tabulation of Tidal Observations in the English Channel, made with the Dover Tide-gauge, and for connecting them with Observations made on the French Coast. PLATE VII. Illustrating the Report of the Committee on the Fossil Plants of the Tertiary and Secondary Beds of the United Kingdom. PLATE VIII. Illustrating the Report of the Committee on the Volcanic Phenomena of Japan. PLATES IX. anp X. Mlustrating Professor Hele Shaw and Mr. Edward Shaw’s Communication, ‘ The Sphere and Roller Mechanism for Transmitting Power.’ PLATE XI. Illustrating Professor Asaph Hall’s Communication, ‘Note on the Orbits of Satellites.’ OBJECTS AND RULES or THE ASSOCIATION. —+——_ OBJECTS. Tur Association contemplates no interference with the ground occupied by other institutions. Its objects are:—To give a stronger impulse and a more systematic direction to scientific inquiry,—to promote the inter- course of those who cultivate Science in different parts of the British Empire, with one another and with foreign philosophers,—to obtain a more general attention to the objects of Science, and a removal of any disadvantages of a public kind which impede its progress. RULES. Admission of Members and Associates. All persons who have attended the first Meeting shall be entitled to become Members of the Association, upon subscribing an obligation to conform to its Rules. 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Members may purchase (for the purpose of completing their sets) any of the volumes of the Reports of the Association up to 1874, of which more than 15 copies remain, at 2s. 6d. per volume.! Application to be made at the Office of the Association, 22 Albemarle Street, London, W. Volumes not claimed within two years of the date of publication can only be issued by direction of the Council. Subscriptions shall be received by the Treasurer or Secretaries. Meetings. The Association shall meet annually, for one week, or longer. The place of each Meeting shall be appointed by the General Committee two years in advance; and the arrangements for it shall be entrusted to the Officers of the Association. General Committee. The General Committee shall sit during the week of the Meeting, or longer, to transact the business of the Association. It shall consist of the following persons :— 1 A few complete sets, 1831 to 1874, are on sale, £10 the set. RULES OF THE ASSOCIATION. Xxix Crass A. PrrMANENT MEMBERS. 1. Members of the Council, Presidents of the Association, and Presi- dents of Sections for the present and preceding years, with Authors of Reports in the Transactions of the Association. 2. Members who by the publication of Works or Papers have fur- thered the advancement of those subjects which are taken into considera- tion at the Sectional Meetings of the Association. Wath a view of sub- mitting new claims under this Rule to the decision of the Cowncil, they must be sent to the Secretary:at least one month before the Meeting of the Association. The decision of the Council on the claims of any Member of the Association to be placed on the list of the General Committee to be final. Crass B. Temporary Mempers.! 1. Delegates nominated by the Corresponding Societies under the conditions hereinafter explained. Claims wnder this Rule to be sent to the Secretary before the opening of the Meeting. 2. Office-bearers for the time being, or delegates, altogether not ex- ceeding three, from Scientific Institutions established in the place of Meeting. Olaims under this Rule to be approved by the Local Secretaries before the opening of the Meeting. 3. Foreigners and other individuals whose assistance is desired, and who are specially nominated in writing, for the Meeting of the year, by the President and General Secretaries. 4, Vice-Presidents and Secretaries of Sections. Organizing Sectional Committees.” The Presidents, Vice-Presidents, and Secretaries of the several Sec- tions are nominated by the Council, and have power to act until their names are submitted to the General Committee for election. From the time of their nomination they constitute Organizing Com- mittees for the purpose of obtaining information upon the Memoirs and Reports likely to be submitted to the Sections,* and of preparing Reports thereon, and on the order in which it is desirable that they should be read, to be presented to the Committees of the Sections at their first meeting. The Sectional Presidents of former years are ex officio members of the Organizing Sectional Committees.* 1 Revised by the General Committee, 1884. 2 Passed by the General Committee, Edinburgh, 1871. 3 Notice to Contributors of Memoirs.—Authors are reminded that, under an arrangement dating from 1871, the acceptance of Memoirs, and the days on which they are to be read, are now as far as possible determined by Organizing Committees for the several Sections before the beginning of the Mecting. It has therefore become necessary, in order to give an opportunity to the Committees of doing justice to the several Communications, that each Author should prepare an Abstract of his Memoir, of a length suitable for insertion ir the published Transactions of the Association, and that he should send it, together with the original Memoir, by book-post, on or DIENER ES witrctevecceh vevebececons , addressed thus—‘ General Secretaries, British Associa- tion, 22 Albemarle Street, London, W. For Section ........’ If it should be incon- venient to the Author that his paper should be read on any particular days, he is requested to send information thereof to the Secretaries in a separate note. Authors who send in their MSS. three complete weeks before the Meeting, and whose papers are accepted, will be furnished, before the Meeting, with printed copies of their Reports and Abstracts. No Report, Paper, or Abstract can be inserted in the Annual Volume unless it is handed either to the Recorder of the Section or to the Secretary, before the conclusion of the Meeting. 4 Added by the General Committee, Sheffield, 1879. XXX RULES OF THE ASSOCIATION, An Organizing Committee may also hold such preliminary meetings as the President of the Committee thinks expedient, but shall, under any circumstances, meet on the first Wednesday of the Annual Meeting, at 11 a.m., to nominate the first members of the Sectional Committee, if they shall consider it expedient to do so, and to settle the terms of their report to the General Committee, after which their functions as an Organizing Committee shall cease.’ Constitution of the Sectional Committees.? On the first day of the Annual Meeting, the President, Vice-Presi- dents, and Secretaries of each Section having been appointed by the General Committee, these Officers, and those previous Presidents and Vice-Presidents of the Section who may desire to attend, are to meet, at 2 p.M., in their Committee Rooms, and enlarge the Sectional Committees by selecting individuals from among the Members (not Associates) present at the Meeting whose assistance they may particularly desire. The Sec- tional Committees thus constituted shall have power to add to their number from day to day. The List thus formed is to be entered daily in the Sectional Minute- Book, and a copy forwarded without delay to the Printer, who is charged with publishing the same before 8 a.m. on the next day in the Journal of the Sectional Proceedings. Business of the Sectional Committees. Committee Meetings are to be held on the Wednesday at 2 P.m., on the following Thursday, Friday, Saturday,? Monday, and Tuesday, from 10 to 11 a.m., punctually, for the objects stated in the Rules of the Association, and specified below. The business is to be conducted in the following manner :— 1. The President shall call on the Secretary to read the minutes of the previous Meeting of the Committee. 2 No paper shall be read until it has been formally accepted by the Committee of the Section, and entered on the minutes accord-. ingly. 3. ee Thich have been reported on unfavourably by the Organiz- ing Committees shall not be brought before the Sectional Committees.‘ At the first meeting, one of the Secretaries will read the Minutes of last year’s proceedings, as recorded in the Minute-Book, and the Synopsis of Recommendations adopted at the last Meeting of the Association and printed in the last volume of the Transactions. He will next proceed to read the Report of the Organizing Committee.6 The list of Communi- cations to be read on Thursday shall be then arranged, and the general distribution of business throughout the week shall be provisionally ap- pointed, At the close of the Committee Meeting the Secretaries shall forward to the Printer a List of the Papers appointed to be read. The Printer is charged with publishing the same before 8 a.m. on Thursday in the Journal. 1 Revised by the General Committee, Swansea, 1880. 2 Passed by the General Committee, Edinburgh, 1871. 3’ The meeting on Saturday was made optional by the General Committee at Southport, 1883. 4 These rules were adopted by the General Committee, Plymouth, 1877. 5 This and the following sentence were added by the General Committee, 1871. RULES OF THE ASSOCIATION, XXXI On the second day of the Annual Meeting, and the following days, the Secretaries are to correct, on a copy of the Journal, the list of papers which have been read on that day, to add to it a list of those appointed to be read on the next day, and to send this copy of the Journal as early in the day as possible to the Printer, who is charged with printing the same before 8 A.M. next morning in the Journal, It is necessary that one of the Secretaries of each Section (generally the Recorder) should call at the Printing Office and revise the proof each evening. ' Minutes of the proceedings of every Committee are to be entered daily in the Minute-Book, which should be confirmed at the next meeting of the Committee. Lists of the Reports and Memoirs read in the Sections are to be entered in the Minute-Book daily, which, with all Memoirs and Copies or Abstracts of Memoirs furnished by Authors, are to be forwarded, at the close of the Sec- tional Meetings, to the Secretary. The Vice-Presidents and Secretaries of Sections become ez officio tem- porary Members of the General Committee (vide p. xxix), and will receive, on application to the Treasurer in the Reception Room, Tickets entitling them to attend its Meetings. The Committees will take into consideration any suggestions which may be offered by their Members for the advancement of Science. They are specially requested to review the recommendations adopted at preceding Meetings, as published in the volumes of the Association and the com- munications made to the Sections at this Meeting, for the purposes of selecting definite points of ‘research to which individual or combined exertion may be usefully directed, and branches of knowledge on the state and progress of which Reports are wanted; to name individuals or Committees for the execution of such Reports or researches ; and to state whether, and to what degree, these objects may be usefully advanced by the appropriation of the funds of the Association, by application to Government, Philosophical Institutions, or Local Authorities, In case of appointment of Committees for special objects of Science, it is expedient that all Members of the Committee should be named, and one of them appointed to act as Secretary, for insuring attention to business. Committees have power to add to their number persons whose assist- ance they may require. The recommendations adopted by the Committees of Sections are to be registered in the Forms furnished to their Secretaries, and one Copy of each is to be forwarded, without delay, to the Secretary for presentation to the Committee of Recommendations. Unless this be done, the Recom- mendations cannot receive the sanction of the Association. N.B.—Recommendations which may originate in any one of the Sec- tions must first be sanctioned by the Committee of that Section before they can be referred to the Committee of Recommendations or confirmed by the General Committee. The Committees of the Sections shall ascertain whether a Report has been made by every Committee appointed at the previous Meeting to whom a sum of money has been granted, and shall report to the Committee of Recommendations in every case where no such Report has been received.} Notices regarding Grants of Money. Committees and individuals, to whom grants of money haye been 1 Passed by the General Committee at Sheffield, 1879. XXxX1i RULES OF THE ASSOCIATION. entrusted by the Association for the prosecution of particular researches in science, are required to present to each following Meeting of the Association a Report of the progress which has been made; and the Individual or the Member first named of a Committee to whom a money grant has been made must (previously to the next Meeting of the Associa- tion) forward to the General Secretaries or Treasurer a statement of the sums which have been expended, and the balance which remains dispos- able on each grant. Grants of money sanctioned at any one Meeting of the Association expire a week before the opening of the ensuing Meeting; nor is the Treasurer authorized, after that date, to allow any claims on account of such grants, unless they be renewed in the original or a modified form by the General Committee. No Committee shall raise money in the name or under the auspices of the British Association without special permission from the General Com- mittee to do so; and no money so raised shall be expended except in accordance with the rules of the Association. In each Committee, the Member first named is the only person entitled to call on the Treasurer, Professor A. W. Williamson, University College, London, W.C., for such portion of the sums granted as may from time to time be required. In grants of money to Committees, the Association does not contem- plate the payment of personal expenses to the members. In all cases where additional grants of money are made for the con- tinuation of Researches at the cost of the Association, the sum named is deemed to include, as a part of the amount, whatever balance may remain unpaid on the former grant for the same object. All Instruments, Papers, Drawings, and other property of the Associa- tion are to be deposited at the Office of the Association, 22 Albemarle Street, Piccadilly, London, W., when not employed in carrying on scien- tific inquiries for the Association. , Business of the Sections. The Meeting Room of each Section is opened for conversation from 10 to 11 daily. The Section Rooms and approaches thereto can be used for no notices, exhibitions, or other purposes than those of the Association. At 11 precisely the Chair will be taken,! and the reading of communi- cations, in the order previously made public, commenced. At 3 p.m. the Sections will close. Sections may, by the desire of the Committees, divide themselves into Departments, as often as the number and nature of the communications delivered in may render such divisions desirable. A Report presented to the Association, and read to the Section which originally called for it, may be read in another Section, at the request of the Officers of that Section, with the consent of the Author. Duties of the Doorkeepers. 1.—To remain constantly at the Doors of the Rooms to which they are appointed during the whole time for which they are engaged. 2.—To require of every person desirous of entering the Rooms the ex- hibition of a Member’s, Associate’s, or Lady’s Ticket, or Reporter’s 1 The meeting on Saturday may begin, if desired by the Committee, at any time not earlier than 10 or later than 11. Passed by the General Committee at Southport, 1883. RULES OF TIE ASSOCIATION. XXXili Ticket, signed by the Treasurer, or a Special Ticket signed by the Secretary. 3.—Persons unprovided with any of these Tickets can only be admitted to any particular Room by order of the Secretary in that Room. No person is exempt from these Rules, except those Officers of the Association whose names are printed in the programme, p. 1. Duties of the Messengers. To remain constantly at the Rooms to which they are appointed dur- ing the whole time for which they are engaged, except when employed on messages by one of the Officers directing these Rooms. Committee of Recommendations. The General Committee shall appoint at each Meeting a Committee, which shall receive and consider the Recommendations of the Sectional Committees, and report to the General Committee the measures which they would advise to be adopted for the advancement of Science. All Recommendations of Grants of Money, Requests for Special Re- searches, and Reports on Scientific Subjects shall be submitted to the Committee of Recommendations, and not taken into consideration by the General Committee unless previously recommended by the Committee of Recommendations. Corresponding Societies. (1.) Any Society is eligible to be placed on the List of Corresponding Societies of the Association which undertakes local scientific investiga- tions, and publishes notices of the results. . (2.) Applications may be made by any Society to be placed on the List of Corresponding Societies. Application must be addressed to the Secretary on or before the Ist of June preceding the Annual Meeting at which it is intended they should be considered, and must be accompanied by specimens of the publications of the results of the local scientific investigations recently undertaken by the Society. 3.) A Corresponding Societies Committee shall be annually nomi- nated by the Council and appointed by the General Committee for the purpose of considering these applications, as well as for that of keeping themselves generally informed of the annual work of the Corresponding Societies, and of superintending the preparation of a list of the papers published by them. This Committee shall make an annuai report to the General Committee, and shall suggest such additions or changes in the List of Corresponding Societies as they may think desirable. (4.) Every Corresponding Society shall return each year, on or before the Ist of June, to the Secretary of the Association, a schedule, properly filled up, which will be issued by the Secretary of the Association, and which will contain a request for such particulars with regard to the Society as may be required for the information of the Corresponding Societies Committee. (5.) There shall be inserted in the Annual Report of the Association a list, in an abbreviated form, of the papers published by the Corre- sponding Societies during the past twelve months which contain the results of the local scientific work conducted by them; those papers only being included which refer to subjects coming under the cognisance of - one or other of the various Sections of the Association. 1 Passed by the General Committee, 1884. 1886. b XXxiv RULES OF THE ASSOCIATION. (6.) A Corresponding Society shall have the right to nominate any one of its members, who is also a Member of the Association, as its dele- gate to the Annual Meeting of the Association, who shall be for the time a Member of the General Committee. Conference of Delegates of Corresponding Societies. (7.) The Delegates of the various Corresponding Societies shall con- stitute a Conference, of which the Chairman, Vice-Chairmen, and Secre- taries shall be annually nominated by the Council, and appointed by the General Committee, and of which the members of the Corresponding Societies Committee shall be ex officio members. (8.) The Conference of Delegates shall be summoned by the Secretaries to hold one or more meetings during each Annual Meeting of the Associa- tion, and shall be empowered to invite any Member or Associate to take part in the meetings. (9.) The Secretaries of each Section shall be instructed to transmit to the Secretaries of the Conference of Delegates copies of any recommen- dations forwarded by the Presidents of Sections to the Committee of Recommendations bearing upon matters in which the co-operation of Corresponding Societies is desired ; and the Secretaries of the Conference of Delegates shall invite the authors of these recommendations to attend the meetings of the Conference and give verbal explanations of their objects and of the precise way in which they would desire to have them carried into effect. (10.) It will be the duty of the Delegates to make themselves familiar with the purport of the several recommendations brought before the Confer- ence, in order that they and others who take part in the meetings may be able to bring those recommendations clearly and favourably before their respective Societies. The Conference may also discuss propositions bear- ing on the promotion of more systematic observation and plans of opera- tion, and of greater uniformity in the mode of publishing results. ; Local Committees. Local Committees shall be formed by the Officers of the Association to assist in making arrangements for the Meetings. Local Committees shall have the power of adding to their numbers those Members of the Association whose assistance they may desire. Officers. A President, two or more Vice-Presidents, one or more Secretaries, and a Treasurer shall be annually appointed by the General Committee. Council. In the intervals of the Meetings, the affairs of the Association shall be managed by a Council appointed by the General Committee. The Council may also assemble for the despatch of business during the week of the Meeting. Papers and Communications. The Author of any paper or communication shall be at liberty to reserve his right of property therein. Accounts. The Accounts of the Association shall be audited annually, by Auditors appointed by the General Committee. 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Pe en ‘bag ‘yrey *¢ = "SOM “CTT ‘AeyssorD “M “H ‘AOU f “bsg ‘oyepsiwp weqieg *¢ "WIN old “4 1ossojorg SOM “CIN SVN “bea ‘taser susay "VIN “bsg ‘orquiosy "A *L PRESIDENTS AND SECRETARIES OF THE SECTIONS. xlili MATHEMATICAL AND PHYSICAL SCIENCES. COMMITTEE OF SCIENCES, I.—MATHEMATICS AND GENERAL PHYSICS. Presidents and Secretaries of the Sections of the Association. Date and Place Presidents Secretaries 1832. Oxford...... Davies Gilbert, D.C.L., F.R.S.|Rev. H. Coddington. 1833. Cambridge | Sir D. Brewster, F.R.S. ......| Prof. Forbes. 1834. Edinburgh | Rev. W. Whewell, F.R.S. Prof. Forbes, Prof. Lloyd. SECTION A.—MATHEMATICS AND PHYSICS. 1835. Dublin...... Rev. Dr. Robinson ......... ...|Prof. Sir W. R. Hamilton, Prof. m Wheatstone. 1836. Bristol...... Rey. William Whewell, F.R.S.|Prof. Forbes, W. 8. Harris, F. W. » Jerrard. 1837. Liverpool...|Sir D. Brewster, F.R.S. ......|W. 8. Harris, Rev. Prof. Powell, ; Prof. Stevelly. 1838. Newcastle |Sir J. F. W. Herschel, Bart.,|Rev. Prof. Chevallier, Major Sabine, E.R.S. 1839, Birmingham | Rey. Prof. Whewell, F.R.S.... 1840, Glasgow ...|Prof. Forbes, F.B.S.........00 1841. Plymouth |Rev. Prof. Lloyd, F.R.S. ...... 1842. Manchester|Very Rev. G. Peacock, D.D., F.R.S. 1843. Cork......... Prof. M‘Culloch, M.R.ILA. ... 1844, York......... The Earl of Rosse, F.R.8. ... 1845. Cambridge |The Very Rev. the Dean of : Ely. 1846, Southamp-|Sir John F. W. Herschel, é ton. Bart., F.R.S. 1847. Oxford...... Rev. Prof. Powell, M.A., ? E-RB.S. 1848. Swansea ...| Lord Wrottesley, F.R.S. ...... 1849, Birmingham | William Hopkins, F.R.S....... 1850. Edinburgh |Prof. J. D. Forbes, F.RB.S., ba Sec. R.S.E. 1851, Ipswich ...)Rev. W. Whewell, D.D., ey F.R.S. 1852. Belfast...... Prof. W. Thomson, M.A., \& F.R.S. L. & E. 1853. Hull......... The Very Rev. the Dean of Ely, F-B.S. al Liverpool...| Prof. G. G. Stokes, M.A., Sec. B.S. isss. Glasgow ...|Rev. Prof. Kelland, M.A., F.R.S. L. & E. 1856. Cheltenham|Rev. R. Walker, M.A., F.R.S. 1857. Dublin...... Rev. T. BR. Robinson, D.D., ‘ F.R.S., M.RB.LA. 1858. Leeds ...... Rev. W. Whewell, D.D., V.P.R.S. 1859, Aberdeen...|The Harl of Rosse, M.A., K.P., | F.B.S. ' : ' Prof. Stevelly. J. D. Chance, W. Snow Harris, Prof. Stevelly. Rey. Dr. Forbes, Prof. Stevelly, Arch. Smith. Prof. Stevelly. Prof. M‘Culloch, Prof. Stevelly, Rev. W. Scoresby. J. Nott, Prof. Stevelly. Rev. Wm. Hey, Prof. Stevelly. John Drew, Dr, Stevelly, G G. Stokes. Rev. H. Price, Prof. Stevelly, G. G. Stokes. Dr. Stevelly, G. G. Stokes. Prof. Stevelly, G. G,. Stokes, W. Ridout Wills. W..J.Macquorn Rankine,Prof.Smyth, Prof. Stevelly, Prof. G. G. Stokes. S. Jackson, W. J. Macquorn Rankine, Prof. Stevelly, Prof. G. G. Stokes. Prof. Dixon, W. J. Macquorn Ran- kine, Prof. Stevelly, J. Tyndall. B. Blaydes Haworth, J. D. Sollitt, Prof. Stevelly, J. Welsh. J. Hartnup, H. G. Puckle, Prof. Stevelly, J. Tyndall, J. Welsh. Rev. Dr. Forbes, Prof. D. Gray, Prof. Tyndall. Brooke, Rev. T. A. Southwood, Prof. Stevelly, Rev. J. C. Turnbull. Prof. Curtis, Prof. Hennessy, P. A. Ninnis, W. J. Macquorn Rankine, Prof. Stevelly. Rey. 8. Earnshaw, J. P. Hennessy, Prof. Stevelly, H.J.S.Smith, Prof. Tyndall. J. P. Hennessy, Prof. Maxwell, H. J. S. Smith, Prof. Stevelly. C. xliv REPORT—1886. Date and Place Presidents Secretaries 1860. Oxford...... Rev. B. Price, M.A., F.R.S....|Rev. G. C. Bell, Rev. T. Rennison, Prof. Stevelly. 1861. ManchesterjG. B. Airy, M.A., D.C.L.,| Prof. R. B. Clifton, Prof. H. J. S. E.RB.S. Smith, Prof. Stevelly. 1862. Cambridge |Prof. G. G. Stokes, M.A.,| Prof. R. B. Clifton, Prof. H. J. S. F.RB.S. Smith, Prof. Stevelly. 1863. Newcastle |Prof.W.J.Macquorn Rankine,| Rev.N.Ferrers,Prof.Fuller,F.Jenkin, C.E., F.R.S. Prof. Stevelly, Rev. C. T. Whitley. 1864. Bath......... Prof. Cayley, M.A., F.R.S.,| Prof. Fuller, F. Jenkin, Rev. G F.R.A.S. Buckle, Prof. Stevelly. 1865. Birmingham] W. Spottiswoode,M.A.,F.R.S.,] Rey. T. N. Hutchinson, F. Jenkin, G. F.R.A.S. S. Mathews, Prof. H. J. 8. Smith, Jd. M. Wilson. 1866. Nottingham|Prof. Wheatstone, D.C.L.,] Fleeming Jenkin, Prof.H.J.S.Smith, F.R.S. Rev. S. N. Swann. 1867. Dundee ...|Prof. Sir W. Thomson, D.C.L.,| Rev. G. Buckle, Prof. G. C. Foster, E.RB.S. Prof. Fuller, Prof. Swan. 1868. Norwich ...|Prof. J. Tyndall, LL.D.,| Prof. G. C. Foster, Rev. R. Harley, F.R.S. R. B. Hayward. 1869, Exeter...... Prof. J. J. Sylvester, LL.D.,| Prof. G. C. Foster, R. B. Hayward, ‘ F.R.S. W. K. Clifford. 1870. Liverpool...|J.. Clerk Maxwell, M.A.,| Prof. W. G. Adams, W. K. Clifford, LL.D., F.R.S. Prof. G. C. Foster, Rev. W. Allen — Whitworth. 1871. Edinburgh |Prof. P. G. Tait, F.R.S.E. ...| Prof. W. G. Adams, J. T. Bottomley, Prof. W. K. Clifford, Prof. J. D Everett, Rev. R. Harley. 1872. Brighton ...]W. De La Rue, D.C.L., F.R.S.| Prof. W. K. Clifford, J. W. L.Glaisher, Prof. A. 8. Herschel, G. F. Rodwell. 1873. Bradford ...|Prof. H. J. S. Smith, F.R.S. | Prof. W. K. Clifford, Prof. Forbes, J. W.L. Glaisher, Prof. A.S. Herschel. 1874. Belfast...... Rey. Prof. J. H. Jellett, M.A.,| J. W. L. Glaisher, Prof. Herschel, M.R.IA. Randal Nixon, J. Perry, G. F. Rodwell. 1875. Bristol...... Prof. Balfour Stewart, M.A.,| Prof. W. F. Barrett, J.W.L. Glaisher, LL.D., F.R.S. C. T. Hudson, G. F. Rodwell. 1876. Glasgow ...|Prof. Sir W. Thomson, M.A.,|Prof. W. F. Barrett, J. T. Bottomley, DICiiiy HERS: Prof. G. Forbes, J. W. L. Glaisher, T. Muir. 1877. Plymouth... | Prof, G. C. Foster, B.A., F.R.8.,| Prof. W. F. Barrett, J. T. Bottomley, Pres. Physical Soc. J. W. L. Glaisher, F. G. Landon. 1878. Dublin...... Rev. Prof. Salmon, D.D.,|Prof. J. Casey, G. F. Fitzgerald, J. D.C.L., F.R.S. W. L. Glaisher, Dr. O. J. Lodge. 1879. Sheffield ...;}George Johnstone Stoney,|A. H. Allen, J. W. L. Glaisher, Dr. M.A., F.R.S. O. J. Lodge, D. MacAlister. 1880. Swansea ...|Prof. W. Grylls Adams, M.A.,}W. E. Ayrton, J. W. L. Glaisher, — F.R.S. Dr. O. J. Lodge, D. MacAlister. LS Sle Yorks aeeet Prof. Sir W. Thomson, M.A.,| Prof. W. E. Ayrton, Prof. 0. J. Lodge, LL.D., D.C.L., F.R.S. D. MacAlister, Rev. W. Routh. 1882. Southamp- |Rt. Hon. Prof. Lord Rayleigh,|W. M. Hicks, Prof. O. J. Lodge, ton. M.A., F.R.S. D. MacAlister, Rev. G. Richardson. 1883. Southport | Prof.O.Henrici,Ph.D.,F.R.S.,)W. M. Hicks, Prof. O. J. Lodge, D. MacAlister, Prof. R. C. Rowe. 1884. Montreal ...| Prof. Sir W. Thomson, M.A.,|C. Carpmael, W. M. Hicks, Prof. A. LL.D., D.C.L., F.R.S Johnson, Prof, O. J. Lodge, Dr. D. MacAlister. 1885. Aberdeen...|Prof. G. Chrystal, M.A.,|R.E. Baynes, R. T. Glazebrook, Prof. F.R.S.E. W. M. Hicks, Prof. W. Ingram. 1886. Birmingham|Prof. G. H. Darwin, M.A.,|R. E. Baynes, R. T. Glazebrook, Prof. LL.D., F.R.S. J. H. Poynting, W. N. Shaw. PRESIDENTS ANU SECRETARIES OF THE SECTIONS. xlv CHEMICAL SCIENCE. COMMITTEE OF SCIENCES, II.—CHEMISTRY, MINERALOGY. Date and Place Presidents Secretaries 1832. Oxford......| John Dalton, D.C.L., F.R.S. |James F. W. Johnston. 1833. Cambridge | John Dalton, D.C.L., F.R.S, | Prof. Miller. meo4. Kdinburgh’ | Dr. Hope.......c...s-ssccssecsecees Mr. Johnston, Dr Christison, i : SECTION B.—CHEMISTRY AND MINERALOGY. 1835. Dublin...... Dr. T. Thomson, F.R.S. ......] Dr. Apjohn, Prof, Johnston, 1836. Bristol...... Rev. Prof. Cumming ......... Dr. Apjohn, Dr. C. Henry, W. Hera- path. 1837. Liverpool...| Michael Faraday, F.R.S....... Prof. Johnston, Prof. Miller, Dr. Reynolds. 1838. Newcastle | Rev. William Whewell,F.R.S.|Prof. Miller, H. L. Pattinson, Thomas Richardson. 1839. Birmingham) Prof. T. Graham, F.R.S. ......| Dr. Golding Bird, Dr. J. B. Melson. 1840. Glasgow ...| Dr. Thomas Thomson, F.R.S.|Dr. R. D. Thomson, Dr. 'T. Clark Dr. L. Playfair. 1841. Plymouth...| Dr. Daubeny, F.R.S. ......... J. Prideaux, Robert Hunt, W. M. > Tweedy. 1842. Manchester | John Dalton, D.C.L., F.R.S. | Dr. L. Playfair, R. Hunt, J. Graham. mp43. Cork......... Prof, Apjohn, M.R.I.A......... R. Hunt, Dr. Sweeny. me44, York......... Prof. T. Graham, F.R.S. ...... | Dr. L. Playfair, E. Solly, T. H. Barker. 1845. Cambridge | Rev. Prof. Cumming ......... BEE J. P. Joule, Prof, Miller, . Solly. 1846, Southamp- | Michael Faraday, D.C.L., | Dr. Miller, R. Hunt, W. Randall. F.R.S . ton a 1847. Oxford...... Rev. W. V. Harcourt, M.A.,|B. C. Brodie, R. Hunt, Prof. Solly. j F.R.S. 1848. Swansea ...| Richard Phillips, F.R.S. ......|T. H. Henry, R. Hunt, T. Williams. 1849, Birmingham|John Percy, M.D., F.R.S....... R. Hunt, G. Shaw. 1850. Edinburgh | Dr. Christison, V.P.R.S.E. Dr. Anderson, R. Hunt, Dr. Wilson.. 1851. Ipswich ...| Prof. Thomas Graham, F.R.S.|T. J. Pearsall, W. S. Ward. 1852. Belfast...... Thomas Andrews,M.D.,F.R.S.|Dr. Gladstone, Prof. Hodges, Prof. Ronalds. 68 1 Prof. J. F. W. Johnston, M.A.,/H. S. Blundell, Prof. R. Hunt, T. J. F.R.S. Pearsall. 1854. Liverpool |Prof.W. A.Miller, M.D.,F.R.S. Dr.Edwards, Dr.Gladstone, Dr.Price.. 1855. Glasgow ...| Dr. Lyon Playfair,C.B.,F.R.S.| Prof. Frankland, Dr. H. E. Roscoe. 1866. Cheltenham| Prof. B. C. Brodie, F.R.S. ...|J. Horsley, P. J. Worsley, Prof. Voelcker. 1857. Dublin...... Prof. Apjohn, M.D., F.R.S.,|Dr. Davy, Dr. Gladstone, Prof. Sul- M.R.LA. livan. 58. Leeds ...... Sir J. F. W. Herschel, Bart.,|Dr. Gladstone, W. Odling, R. Rey- D.C.L nolds. 9. Aberdeen...! Dr. Lyon Playfair, C.B.,F.R.S.|J. 8. Brazier, Dr. Gladstone, G. D.. Liveing, Dr. Odling. 0. Oxford...... Prof. B. C. Brodie, F.R.S......|A. Vernon Harcourt, G. D. Liveing,. A. B. Northcote. 1861. Manchester| Prof. W.A.Miller, M.D.,F.R.S.|A. Vernon Harcourt, G. D. Liveing. 1862. Cambridge | Prof. W.A.Miller, M.D.,F.R.S.|H. W. Elphinstone, W. Odling, Prof. Roscoe. 1863. Newcastle |Dr. Alex. W. Williamson,| Prof. Liveing, H. L. Pattinson, J. C. y | E.R.S. Stevenson. 1864. Bath......... W.Odling, M.B.,F.R.S.,F.C.S. A.V.Harcourt,Prof.Liveing,R. Biggs. 1865. Birmingham|Prof. W. A. Miller, M.D.,]A. V. Harcourt, H. Adkins, Prof. ; V.P.R.S. Wanklyn, A. Winkler Wills. 1866. Nottingham |H. Bence Jones, M.D., F.R.S.|J. H. Atherton, Prof, Liveing, W. J. Russell, J. White. xlvi REPORT—1886. Date and Place Presidents Secretaries 1867. Dundee ...|Prof. T. Anderson, M.D.,|A. Crum Brown, Prof. G. D. Liveing, F.R.S.E. W. J. Russell. 1868. Norwich ...|Prof. E. Frankland, F.R.S..|Dr. A. Crum Brown, Dr. W. J. Rus- F.C.S. sell, F. Sutton. 1869. Exeter...... Dr. H. Debus, F.R.S., F.C.S. |Prof. A. Crum Brown, Dr. W. J. Russell, Dr. Atkinson. 1870. Liverpool...|Prof. H. E. Roscoe, B.A.,)Prof.A. Crum Brown, A. E. Fletcher, F.R.S., F.C.S. Dr. W. J. Russell. 1871. Edinburgh. | Prof. T. Andrews, M.D.,F.R.S.|J. T. Buchanan, W. N. Hartley, T. E. Thorpe. 1872. Brighton ...|Dr. J. H. Gladstone, F.R.S....| Dr. Mills, W. Chandler Roberts, Dr. W. J. Russell, Dr. T. Wood. 1873. Bradford ...|Prof. W. J. Russell, F.R.S....) Dr. Armstrong, Dr. Mills, W. Chand- ler Roberts, Dr. Thorpe. 1874. Belfast...... Prof. A. Crum Brown, M.D.,| Dr. T. Cranstoun Charles, W. Chand- F.R.S.E., F.C.S. ler Roberts, Prof. Thorpe. 1875. Bristol..:.... A. G. Vernon Harcourt, M.A.,/ Dr. H. E. Armstrong, W. Chandler F.R.S., F.C.S. Roberts, W. A. Tilden. 1876. Glasgow ...|W. H. Perkin, F.R.S. .........)W. Dittmar, W. Chandler Roberts, 1882. 1883. 1884. Montreal ... 1885. Aberdeen... 1886, Birmingham . Dublin . Plymouth... aeeeee . Sheffield ... . Swansea ... Southamp- ton. Southport F. A. Abel, F.R.S., F.C.S. ... Prof. Maxwell Simpson, M.D., F.RB.S., F.C.8. Prof. Dewar, M.A., F.R.S. Joseph Henry Gilbert, Ph.D., F.R.S. Prof. A. W. Williamson, Ph.D., F.R.S. Prof. G. D. Liveing, M.A., F.R.S. Dr. J. H. Gladstone, F.R.S... Prof. Sir H. E. Roscoe, Ph.D., LL.D., F.R.S. : Prof. H. E. Armstrong, Ph.D., F.R.S., Sec. C.S. W. Crookes, F.R.S., V.P.C.S. J. M. Thomson, W. A. Tilden. Dr. Oxland, W. Chandler Roberts, J. M. Thomson. \W. Chandler Roberts, J. M. Thom- son, Dr. C. R. Tichborne, T. Wills. H. S. Beli, W. Chandler Roberts, J. M. Thomson. H. B. Dixon, Dr. W. R. Eaton Hodg- kinson, P. Phillips Bedson, J. M. Thomson. P. Phillips Bedson, H. B. Dixon, T. Gough. P. Phillips Bedson, H. B. Dixon, J. L. Notter. Prof. P. Phillips Bedson, Dixon, H. For edson, H. : Prof. P. Phillips B of, W. B. Dixon, T. McFarlane, Pr H. Pike. | Prof. P. Phillips BedS°™) H, B. Dixon, H.ForsterMorley,Dr.W.J.Simpson. \Prof. P. Phillips Bedson, H. B. Dixon, H. Forster Morley, W. W. | J. Nicol, C. J. Woodward. HTB GEOLOGICAL (anp, untTin 1851, GEOGRAPHICAL) SCIENCE. COMMITTEE OF SCIENCES, III.—GEOLOGY AND GEOGRAPHY. 1832. 1833. 1834. 1835. 1836. 1837. Oxford Dublin Bristol Liverpool... Cambridge./G. B. Greenough, F.R.S. a. Edinburgh .| Prof. Jameson R. I. Murchison, F.R.S. .. rere eee rere eey SECTION R. J. Griffith Rev. Dr. Buckland, F.R.S.— Geography, R.1I. Murchison, F.R.S. seem eee eneeseseeeee Rev. Prof. Sedgwick, F.R.S.— Geography,G.B.Greenough, E.R.S. .|John Taylor. W. Lonsdale, John Phillips. Prof. Phillips, T. Jameson Torrie, Rev. J. Yates. C.—GEOLOGY AND GEOGRAPHY. ‘Captain Portlock, T. J. Torrie. William Sanders, 8. Stutchbury, T. J. Torrie. Captain Portlock, R. Hunter.—@eo- grep Captain H. M. Denham, PRESIDENTS AND SECRETARIES Date and Place Presidents 1838. Newcastle. .|C. Lyell, F.R.S., V.P.G.S.— Geography, Lord Prudhope. 839. Birmingham| Rev. Dr. Buckland, F.R.S.— Geography, G.B.Greenough, F.RS. 840. Glasgow ...|Charles Lyell, F.R.S.—Geo- graphy, G. B. Greenough, E.R.S. 1841. Plymouth...|H. T. De la Beche, F.R,S. ... 1842, Manchester |R. I. Murchison, F.R.S. 1843. Cork......... M.R.LA. 844. York......... Henry Warburton, M.P., Pres. Geol. Soc. 1845. Cambridge.|Rev. Prof. Sedgwick, M.A., F.R.S. . Southamp- | Leonard Horner,F.R.S.—Geo- tor. graphy, G. B. Greenough, F.R.S. OF THE SECTIONS. xlvii Secretaries W.C. Trevelyan, Capt. Portlock.— Geography, Capt. Washington. George Lloyd, M.D., H. E. Strick- land, Charles Darwin. W. J. Hamilton, D. Milne, Hugh Murray, H. E. Strickland, John Scoular, M.D. W.J.Hamilton,Edward Moore, M.D., R. Hutton. E. W. Binney, R. Hutton, Dr. R. Lloyd, H. E. Strickland. Richard E. Griffith, F.R.S.,| Francis M. Jennings, H. E. Strick- land. Prof. Ansted, E. H. Bunbury. Rev. J. C. Cumming, A. C. Ramsay, Rev. W. Thorp. Robert A, Austen, Dr. J. H. Norton, Prof. Oldham.— Geography, Dr. C. T. Beke. Prof. Ansted, Prof. Oldham, A. C. Ramsay, J. Ruskin. Starling Benson, Prof. Prof. Ramsay. J. Beete Jukes, Prof. Oldham, Prof. A. C. Ramsay. Oldham, 1847. Oxford...... Very Rev.Dr.Buckland,F.R.S. 1848. Swansea ...|Sir H. T. De la Beche, C.8., ’ F.R.S. 1849.Birmingham|Sir Charles Lyell, F.R.S., F.G.S. 1850. Edinburgh'|Sir Roderick I. Murchison, P F.R.S. 1851. Ipswich ...| WilliamHopkins, M.A.,F.R.S. 1852. Belfast...... Lieut.-Col. Portlock, R.E., F.R.S. eH eeETUL .. 502.0. Prof. Sedgwick, F.R.S......... 1854. Liverpool ..|Prof. Edward Forbes, F,R.S. 1855. Glasgow ...|Sir R. I. Murchison, F.R.S.... 1856. Cheltenham | Prof. A? C. Ramsay, F.R.S.... 1857. Dublin...... The Lord Talbot de Malahide 858. Leeds ...... William Hopkins,M.A.,LL.D., F.R.S. 1859. Aberdeen...|Sir Charles Lyell, LL.D., D.C.L., F.R.S. . Oxford ......)Rev. Prof. Sedgwick, LL.D., F.R.S., F.G.S. . Manchester |Sir R. I. Murchison, D.C.L., , LL.D., F.RB.S. 1862. Cambridge |J. Beete Jukes, M.A., F.R.S. 1 At a meeting of the General Committee SECTION © (continued). A. Keith Johnston, Hugh Miller, Prof. Nicol. — GEOLOGY. C. J. F. Bunbury, G. W. Ormerod, Searles Wood. James Bryce, James MacAdam, Prof. M‘Coy, Prof. Nicol. Prof. Harkness, William Lawton. John Cunningham, Prof. Harkness, G. W. Ormerod, J. W. Woodall. James Bryce, Prof. Harkness, Prof. Nicol. Rev. P. B. Brodie, Rev. R. Hep- worth, Edward Hull, J. Scougall, T. Wright. Prof. Harkness, Gilbert Sanders, Robert H. Scott. Prof. Nicol, H.! C. Sorby, E. W. Shaw. Prof. Harkness, Rev. J. Longmuir, H. C. Sorby. Prof. Harkness, Edward Hull, Capt. D. C. L. Woodall. Prof. Harkness, Edward Hull, T. Rupert Jones, G. W. Ormerod. Lucas Barrett, Prof. T. Rupert Jones, H. C. Sorby. held in 1850, it was resolved ‘ That the subject of Geography be separated from Geology and combined with Ethnology, to constitute a separate Section, under the title of the “Geographical and Ethno- logical Section,”’’ for Presidents and Secretaries of which see page lii. xlvili REPORT—-1886. Date and Place Presidents Secretaries 1863. Newcastle |Prof. Warington W. Smyth, F.B.S., F.G.S. 1864. Bath......... Prof. J. Phillips, LL.D., F.R.S., F.G.S. 1865. Birmingham |Sir R. I. Murchison, Bart., K.C.B. 1866. Nottingham] Prof. A. C. Ramsay, LL.D., E.B.S. 1867. Dundee ...|Archibald Geikie, F.R.S., F.G.S8. 1868. Norwich ...|R. A. C. Godwin-Austen, F.B.S., F.G.S. 1869. Exeter ...... Prof. R. Harkness, F.R.S., F.G,5. 1870. Liverpool...|Sir Philipde M.Grey Egerton, Bart., M.P., F.R.S. 1871. Edinburgh |Prof. A. Geikie, F.R.S., F.G.S. 1872. Brighton...|R. A. C. Godwin-Austen, F.R.S., F.G.S. 1873. Bradford...|Prof. J. Phillips, D.C.L., E.R.S., F.G.S. Prof. Hull, M.A., F.R.S., E.G.S. Dr. Thomas Wright, F.R.S.E., F.G.S. .|Prof. John Young, M.D....... 1874. Belfast...... 1875. Bristol...... 1876. Glasgow .. 1877. Plymouth...|W. Pengelly, F.R.S.......0.000. John Evans, D.C.L., F.R.S., F.S.A., F.G.S. 1879. Sheffield ...|Prof.P. Martin Duncan, M.B., F.R.S., F.G.S. 1880. Swansea ...}H. a sores IDI AIDES arise F.G.S8. A. C. Ramsay, LU.D., F.R.8., E.G.S. R. Etheridge, F.R.S., F.G.S. 1878. Dublin...... GST EVOL K ancatcs . 1882. Southamp- ton. 1883. Southport |Prof. W. C. Williamson, LL.D., F.R.S. 1884. Montreal ...]W. T. Blanford, F.R.S., Sec. G.S. 1885. Aberdeen...}Prof. J. W. Judd, F.R.S., Sec. G.S - 1886. Birmingham Prof. T. G. Bonney, D.S&c., LL.D., F.R.8., F.G.S. E. F. Boyd, John Daglish, H. C, Sorby, Themas Sopwith. W. B. Dawkins, J. Johnston, H. C0, Sorby, W. Pengelly. Rev. P. B. Brodie, J. Jones, Rev. E. Myers, H. C. Sorby, W. Pengelly. R. Etheridge, W. Pengelly, T. Wil- sor, G. H. Wright. Edward Hull, W. Pengelly, Henry Woodward. Rev. O. Fisher, Rev. J. Gunn, W. Pengelly, Rev. H. H. Winwood. W. Pengelly, W. Boyd Dawkins, Rey. H. H. Winwood. W. Pengeliy, Rev. H. H. Winwood, W. Boyd Dawkins, G. H. Morton. R. Etheridge, J. Geikie, T. McKenny Hughes, L. C. Miall. L. C. Miall, George Scott, Willian Topley, Henry Woodward. L. C. Miall, R. H. Tiddeman, W. Topley. F. Drew, L. C. Miall, R. G. Symes, R. H. Tiddeman. L. C. Miall, E. B. Tawney, W. Top- ley. J. Armstrong, F. W. Rudler, W.. Topley. Dr. Le Neve Foster, R. H. Tidde- man, W. Topley. HE. T. Hardman, Prof. J. O’Reilly, R. H. Tiddeman. W. Topley, G. Blake Walker. W. Topley, W. Whitaker. J. E. Clark, W. Keeping, W. Topley, W. Whitaker. T. W. Shore, W. Topley, E. West- lake, W. Whitaker. R. Betley, C. E. De Rance, W. Top- ley, W. Whitaker. F. Adams, Prof. E. W. Claypole, W-. Topley, W. Whitaker. C. E. De Rance, J. Horne, J. J. H Teall, W. Topley. W. J. Harrison, J. J. H. Teall, W. Topley, W. W. Watts. BIOLOGICAL SCIENCES. COMMITTEE OF SCIENCES, IV.—ZOOLOGY, BOTANY, PHYSIOLOGY, ANATOMY. 1832. Oxford...... Rev, P. B. Duncan, F.G.S. ...| Rev. Prof. J. 8. Henslow. 1833. Cambridge'| Rev. W.L. P. Garnons, F.L.S.|C. C. Babington, D. Don. 1834. Edinburgh .| Prof. Graham..............csse00. W. Yarrell, Prof. Burnett. 1 At this Meeting Physiology and Anatomy were made a separate Committee, for Presidents and Secretaries of which see p. li, Sa eet CATS PRESIDENTS AND SECRETARIES OF THE SECTIONS. xlix SECTION D.—ZOOLOGY AND BOTANY. Date and Place Presidents Secretaries 1835. Dublin...... DrvAllman -Wobsccvecccvede sees J. Curtis, Dr. Litton. 1836. Bristol...... Rev. Prof. Henslow ........+00+ J. Curtis, Prof. Don, Dr. Riley, 8. Rootsey. 1837. Liverpool...;W. S. MacLeay..,.........ssesee- C. C. Babington, Rev. L. Jenyns, W. Swainson. 1838. Newcastle (Sir W. Jardine, Bart. ......... J. E. Gray, Prof. Jones, R. Owen, Dr. Richardson. 1839. Birmingham | Prof. Owen, F.R.S. ..........+ E. Forbes, W. Ick, R. Patterson. 1840. Glasgow ...|Sir W. J. Hooker, LL.D....... Prof. W. Couper, E. Forbes, R. Pat- terson. 1841. Plymouth... | 1842. Manchester | 1843. Cork......... MES, VOLK. cccsses. 1845, Cambridge 1846, Southamp- ton. John Richardson, M.D., F.R.S.| J. Couch, Dr. Lankester, R. Patterson. Hon. and Very Rev. W. Her-|Dr. Lankester, R. Patterson, J. A. bert, LL.D., F.L.S. Turner. William Thompson, F.L.S....|G. J. Allman, Dr. Lankester, R. Patterson. \Very Rey. the Dean of Man-| Prof. Allman, H. Goodsir, Dr. King, chester. Dr. Lankester. Rey. Prof. Henslow, F.1.S....|Dr. Lankester, T. V. Wollaston, Sir J. Richardson, M.D., |Dr. Lankester, T. V. Wollaston, H. 1847. Oxford...... F.R.S. Wooldridge. H. E. Strickland, M.A., F.R.S.|Dr. Lankester, Dr. Melville, T. V. Wollaston. SECTION D (continued).—ZOOLOGY AND BOTANY, INCLUDING PHYSIOLOGY. [For the Presidents and Secretaries of the Anatomical and Physiological Subsec- tions and the temporary Section E of Anatomy and Medicine, see p. li.] 1848. Swansea ... 1849, Birmingham 1850. Edinburgh 1851. Ipswich 1852. Belfast...... 1853. 1854. 1855. 1856. Jefe a Liverpool... Glasgow .. Cheltenham 1857. Dublin...... 1858. Leeds ...... 1859. Aberdeen... 1860. 1861. Manchester 1862. 1863. Cambridge Newcastle 1864. 1865. Birmingham|T. Thomson, M.D., F.R.S. ... 1886. ...|Rev. Prof. Henslow, M.A., .|Rev. Dr. Fleeming, F.R.S.E. Dr. R. Wilbraham Falconer, A, Hen- frey, Dr. Lankester. Dr. Lankester, Dr. Russell. Prof. J. H. Bennett, M.D., Dr. Lan- kester, Dr. Douglas Maclagan. Prof. Allman, F. W. Johnston, Dr. E. Lankester. Dr. Dickie, George C. Hyndman, Dr. Edwin Lankester. Robert Harrison, Dr. E. Lankester. Isaac Byerley, Dr. E. Lankester. William Keddie, Dr. Lankester. Dr. J. Abercrombie, Prof. Buckman, Dr. Lankester. Prof, J. R. Kinahan, Dr. E. Lankester, Robert Patterson, Dr. W. E. Steele. Henry Denny, Dr. Heaton, Dr. E. Lankester, Dr. E. Perceval Wright. Prof. Dickie, M.D., Dr. E. Lankester, Dr. Ogilvy. W.S. Church, Dr. E. Lankester, P. L. Sclater, Dr. E. Perceval Wright. Dr. T. Alcock, Dr. E. Lankester, Dr. P. L. Sclater, Dr. E. P. Wright. Alfred Newton, Dr. E. P. Wright. Dr. E. Charlton, A. Newton, Rev. H. B. Tristram, Dr. E. P. Wright. .|H. B. Brady, C. E. Broom, H. T. Stainton, Dr. E. P. Wright. Dr. J. Anthony, Rev. C. Clarke, Rev. H. B. Tristram, Dr. E. P. Wright. Cc L. W. Dillwyn, F.RB.S.......... William Spence, F.R.S. ...... Prof. Goodsir, F.R.S. L. & E. F.R.S. Pete eeeweeeeeeeessseeses C. C. Babington, M.A., F.R.S. Prof. Balfour, M.D., F.R.S.... Thomas Bell, F.R.S., Pres.L.S. Prof. W. H. Harvey, M.D., F.R.S. C. C. Babington, M.A., F.R.S. Sir W. Jardine, Bart., F.R.S.E. Rey. Prof. Henslow, F.L.S.... Prof. C. C. Babington, F.R.S. Prof. Huxley, F.R.S. Prof. Balfour, M.D., F.R.S.... Dr. John E. Gray, F.R.S. REPORT—1886. SECTION D (continued) —x1oLoGy.! Date and Place Presidents "1866. 1867. - 1868. 1869. 1870. 1871. 1872. 1873. 1874, 1875. 1876. 1877. Secretaries Nottingham] Prof. Huxley, LL.D., F.R.S.|Dr. J. Beddard, W. Felkin, Rev. H. —Physiological Dep., Prof.| B. Tristram, W. Turner, E. B. Humphry, M.D., F.R.S.—| Tylor, Dr. E. P. Wright. Anthropological Dep., Alf. R. Wallace, F.R.G.S. Dundee ...| Prof. Sharpey, M.D., Sec. R.S.|C. Spence Bate, Dr. 8. Cobbold, Dr. —Dep. of Zool. and Bot.,| M. Foster, H.T. Stainton, Rey. H. George Busk, M.D., F.R.S. B, Tristram, Prof. W. Turner. Norwich ...|Rev. M. J. Berkeley, F.L.S.|Dr. T. 8S. Cobbold, G. W. Firth, Dr. —Dep. of Physiology, W.| M. Foster, Prof. Lawson, H. T. H. Flower, F.R.S. Stainton, Rey. Dr. H. B. Tristram, Dr. E. P. Wright. Exetet ...... George Busk, F.R.S., F.L.8.|Dr. T. 8. Cobbold, Prof. M. Foster, —Dep. of Bot. and Zool.,| E. Ray Lankester, Prof. Lawson, C. Spence Bate, F.R.S.—| H. T Stainton, Rev. H. B. Tris- Dep. of Ethno., E. B. Tylor.| tram. Liverpool..,| Prof.G. Rolleston, M.A., M.D.,|Dr. T. 8. Cobbold, Sebastian Evans, F.R.S., F.L.S.—Dep. of| Prof. Lawson, Thos. J. Moore, H. Anat. and Physiol.,Prof.M.| TT. Stainton, Rev. H. B. Tristram, Foster, M.D., F.L.8.—Dep.| C. Staniland Wake, E. Ray Lan- of Ethno., J. Evans, F.R.S. kester. Edinburgh |Prof. Allen Thomson, M.D.,|Dr. T. R. Fraser, Dr. Arthur Gamgee, F.R.S.—Dep. of Bot. and| HE. Ray Lankester, Prof. Lawson, Zool.,Prof.WyvilleThomson,| 4H. T. Stainton, C. Staniland Wake, F.R.S.—Dep. of Anthropol.,| Dr. W. Rutherford, Dr. Kelburne Prof. W. Turner, M.D. King. : Brighton ...|SirJ. Lubbock, Bart.,F.R.S.— | Prof. Thiselton-Dyer, H. T. Stainton, Dep. of Anat. and Physiol.;| Prof. Lawson, F. W. Rudler, J. H. Dr. Burdon Sanderson,} Lamprey, Dr. Gamgee, E. Ray F.R.S.—Dep. of Anthropol.,| Lankester, Dr. Pye-Smith. Col. A. Lane Fox, F.G.5. Bradford ..,| Prof. Allman, F.R.S.—Dep. of Anat.and Physiol.,Prof, Ru- therford, M.D.— Dep. of An- thropol., Dr. Beddoe, F.R.S. Belfast ...... Prof. Redfern, M.D.—Dep. of Zool. and Bot., Dr. Hooker, C.B.,Pres.R.S.—Dep. of An- throp.,Sir W.R. Wilde, M.D. Bristol ...... P. L. Sclater, F.R.S.— Dep. of Anat.and Physiol.,Prof.Cle- land, M.D., F.R.S.-—Dep. of Anthropol., Prof. Rolleston, M.D., F.RB.S. Glasgow ...|A. Russel Wallace, F.R.G.S., F.L.S.—Dep. of Zool. and Bot., Prof. A. Newton, M.A., F.R.S.—Dep. of Anat. and Physiol., Dr. J. G. McKen- drick, F.R.S.E. Plymouth... |J.GwynJeffreys, LL.D.,F.RS., F.L.S.—Dep. of Anat. and Physiol., Prof. Macalister, M.D.—Dep. of Anthropol., Francis Galton, M.A.,F.R.S. Prof. Thiselton-Dyer, Prof. Lawson, R. M‘Lachlan, Dr. Pye-Smith, E. Ray Lankester, F. W. Rudler, J. H. Lamprey. W.T. Thiselton- Dyer, R. O. Cunning- ham, Dr. J. J. Charles, Dr. P. H. Pye-Smith, J. J. Murphy, F. W. Rudler. E. R. Alston, Dr. McKendrick, Prof. W. R. M‘Nab, Dr. Martyn, F. W. Rudler, Dr. P. H. Pye-Smith, Dr. W. Spencer. E. R. Alston, Hyde Clarke, Dr. Knox, Prof. W. R. M‘Nab, Dr. Muirhead, Prof. Morrison Wat- son. E. R. Alston, F. Brent, Dr. D. J. Cunningham, Dr. C. A. Hingston, Prof. W. R. M‘Nab, J. B. Rowe, F. W. Rudler. 1 At a meeting of the General Committee in 1865, it was resolved :—‘ That the title of Section D be changed to Biology ;’ and ‘That for the word “Subsection,” in the . rules for conducting the business of the Sections, the word “ Department” be substituted.’ ee” Ss PRESIDENTS AND SECRETARIES OF THE SECTIONS. li Date and Place : Presidents . Secretaries 1878. Dublin ...... Prof. W. H. Flower, F.R.S.—|Dr. R. J. Harvey, Dr. T. Hayden, Dep. of Anthropol., Prof.| Prof. W. R. M‘Nab, Prof. J. M. Huxley, Sec. R.S.—Dep.| Purser, J. B. Rowe, F. W. Rudler. of Anat. and Physiol., R. McDonnell, M.D., F.R.S. 1879. Sheffield ...}Prof. St. George Mivart,|Arthur Jackson, Prof. W. R. M‘Nab, F.R.S.— Dep. of Anthropol.,| J.B. Rowe, F. W. Rudler, Prof. EK. B. Tylor, D.C.L., F.R.S.| Schafer. —Dep. of Anat. and Phy- siol., Dr. Pye-Smith. 1880. Swansea ...|A. C. L. Giinther, M.D.,F.R.S.|G. W. Bloxam, John Priestley, —Dep. of Anat. and Phy-| Howard Saunders, Adam Sedg- siol., F. M. Balfour, M.A.,} wick. F.R.S.— Dep. of Anthropol., F. W. Rudler, F.G.S. 1881. York......... Richard Owen, C.B., M.D.,}G. W. Bloxam, W. A. Forbes, Rev. F.R.S.—Dep.of Anthropol.,| W. C. Hey, Prof. W. R. M‘Nab, Prof. W. H. Flower, LL.D.,}_ W. North, John Priestley, Howard F.R.S.—Dep. of Anat. and| Saunders, H. E. Spencer. Physiol., Prof. J. 8. Burdon " Sanderson, M.D., F.R.S. 1882. Southamp- |Prof. A. Gamgee, M.D., F.R.S8.|G. W. Bloxam, W. Heape, J. B. ton. — Dep. of Zool. and Bot.,| Nias, Howard Saunders, A. Sedg- Prof. M. A. Lawson, M.A.,| wick, T. W. Shore, jun. F.L.S.— Dep. of Anthropol., Prof. W. Boyd Dawkins, M.A., F.R.S. 1883. Southport! |Prof. E. Ray Lankester, M.A.,]G. W. Bloxam, Dr. G. J. Haslam, F.R.S.— Dep. of Anthropol.,| W. Heape, W. Hurst, Prof. A. M. W. Pengelly, F.R.S. Marshall, Howard Saunders, Dr. G. A. Woods. 1884. Montreal?...|Prof. H. N. Moseley, M.A.,|Prof. W. Osler, Howard Saunders, A. F.RB.S. Sedgwick, Prof. R. R. Wright. 1885. Aberdeen... |Prof. W. C. McIntosh, M.D.,|W. Heape, J. McGregor-Robertson, LL.D., F.R.S. L. & E.+ J. Duncan Matthews, Howard Saunders, H. Marshall Ward. 1886. Birmingham |W. Carruthers, Pres. L.S.,|Prof. T. W. Bridge, W. Heape, Prof. F.RB.S., F.G.S8. W. Hillhouse, W. L. Sclater, Prof, P H. Marshall Ward. ANATOMICAL AND PHYSIOLOGICAL SCIENCES. COMMITTEE OF SCIENCES, V.—ANATOMY AND PHYSIOLOGY. 1833. Cambridge |Dr. Haviland...............c0000 Dr. Bond, Mr, Paget. 1834, Edinburgh | Dr. Abercrombie ...........000. Dr. Roget, Dr. William Thomson. SECTION E (UNTIL 1847).—ANATOMY AND MEDICINE. 1835. Dublin ...... Dr. Pritchard ).tes..svase.sseeares Dr. Harrison, Dr. Hart. 1836. Bristol ...... Dr. Roget, F.R.S. ......sssseceee Dr. Symonds. 1837, Liverpool...}Prof. W. Clark, M.D. ......... Dr. J. Carson, jun., James Long, Dr. J. R. W. Vose. 1838. Newcastle |T. E. Headlam, M.D. ......... T. M. Greenhow, Dr. J. R. W. Vose. 1839. Birmingham|John Yelloly, M.D., F.R.S....|Dr. G. O. Rees, F. Ryland. j 1840. Glasgow ...|James Watson, M.D. ......... Dx: re Brown, Prof. Couper, Prof. Reid. ? By direction of the General Committee at Southampton (1882) the Departments of Zoology and Botany and of Anatomy and Physiology were amalgamated. ? By authority of the General Committee, Anthropology was made a separate Section, for Presidents and Secretaries of which see p. lvii. c2 lii REPORT—1886. SECTION E.—PHYSIOLOGY. Date and Place Presidents Secretaries 1841. Plymouth...|P. M. Roget, M.D., Sec. B.S. |Dr. J. Butter, J. Fuge, Dr. R. S. Sargent. 1842. Manchester | Edward Holme, M.D., F.L.S.| Dr. Chaytor, Dr. R. S. Sargent. 1843. Cork .......+- Sir James Pitcairn, M.D. ...|Dr. John Popham, Dr. R. S. Sargent. 1844 York......... J. C. Pritchard, M.D. ......... I. Erichsen, Dr. R. 8. Sargent. 1845. Cambridge |Prof. J. Haviland, M.D. ......|Dr. R. S. Sargent, Dr. Webster. 1846. Southamp- |Prof. Owen, M.D., F.R.S. ...|C. P. Keele, Dr. Laycock, Dr. Sar- ton. gent. 1847. Oxford’ ...|Prof. Ogle, M.D., F.R.S. ......|Dr. Thomas K. Chambers, W. P. Ormerod. PHYSIOLOGICAL SUBSECTIONS OF SECTION D. 1850. Edinburgh | Prof. Bennett, M.D., F.R.S.E. 1855. Glasgow ...|Prof. Allen Thomson, F.R.S. |Prof. J. H. Corbett, Dr. J. Struthers. 1857. Dublin...... Prof. R. Harrison, M.D. ...... Dr. R. D. Lyons, Prof. Redfern. 1858. Leeds ...... Sir Benjamin Brodie, Bart.,|C. G. Wheelhouse. F.R.S. , 1859. Aberdeen... | Prof. Sharpey, M.D., Sec.R.S.|Prof. Bennett, Prof. Redfern. 1860. Oxford...... Prof.G.Rolleston,M.D.,F.L.S.| Dr. R. M‘Donnell, Dr. Edward Smith. 1861. Manchester | Dr. John Davy, F.R.S.L.& E.| Dr. W. Roberts, Dr. Edward Smith. 1862. Cambridge |G. E. Paget, M.D.............04. G. F. Helm, Dr. Edward Smith. 1863. Newcastle |Prof. Rolleston, M.D., F.R.S.|Dr. D. Embleton, Dr. W. Turner. S64 Bath. ccscssc Dr. Edward Smith, LL.D.,|J.S, Bartrum, Dr. W. Turner. F.R.S. 1865. Birming- Prof. Acland, M.D., LL.D.,jDr. A. Fleming, Dr. P. Heslop, ham.” F.R.S. Oliver Pembleton, Dr. W. Turner. GEOGRAPHICAL AND ETHNOLOGICAL SCIENCES. [For Presidents and Secretaries for Geography previous to 1851, see Section C, p. xlvi.] ETHNOLOGICAL SUBSECTIONS OF SECTION D. 1846.Southampton) Dr. Pritchard...............c0000+ Dr. King. 1847. Oxford...... Prof. H. H. Wilson, M.A. .../Prof. Buckley. His Ee WEAESCA Leal pos dseavensropescsannreneeacarsnasecsis G. Grant Francis. NSO DUTTON MATH |\ccapescsescsess dausie spear pierce sect Dr. R. G. Latham. 1850. Edinburgh | Vice-Admiral Sir A. Malcolm! Daniel Wilson. SECTION E.—GEOGRAPHY AND ETHNOLOGY. 1851. Ipswich ...|Sir R. I. Murchison, F.R.S8.,|R. Cull, Rev. J. W. Donaldson, Dr. Pres. R.G.S. Norton Shaw. 1852. Belfast...... Col. Chesney, R.A., D.C.L.,}/R. Cull, R. MacAdam, Dr. Norton F.R.S. Shaw. USbos HO cccesse R. G. Latham, M.D., F.R.S. |R. Cull, Rev. H. W. Kemp, Dr. Norton Shaw. 1854. Liverpool...}Sir R. I. Murchison, D.C.L.,| Richard Cull, Rev. H. Higgins, Dr. F.R.S. Ihne, Dr. Norton Shaw, 1855. Glasgow ...|Sir J. Richardson, M.D.,|Dr. W. G. Blackie, R. Cull, Dr. F.R.S. Norton Shaw. 1856. Cheltenham|Col. Sir’ H. C. Rawlinson,}R. Cull, F. D. Hartland, W. H. K.C.B. Rumsey, Dr. Norton Shaw. 1857. Dublin...... Rev. Dr. J. Henthorn Todd,|R. Cull, 8. Ferguson, Dr. R. R. Pres. R.I.A. Madden, Dr. Norton Shaw. ' By direction of the General Committee at Oxford, Sections D and E were incorporated under the name of ‘Section D—Zoology and Botany, including Phy- siology’ (see p. xlix). The Section being then vacant was assigned in 1851 to Geography. 2 Vide note on page L PRESIDENTS AND SECRETARIES OF THE SECTIONS. liii Date and Place 1858, 1859. 1860. 1861. 1862.. 1863. 1864, Leeds ...... Aberdeen... Manchester Cambridge Newcastle 1865. Birmingham 1866. Nottingham 1867. 1868, 1869. 1870. 1871, 1872. 1873.. 1874. 1875. 1876. 1877, 1878, 1879, 1880. 1881. 1882. 1883. Dundee Norwich ... Exeter ...... Liverpool... Edinburgh Brighton ... Bradford ... Belfast...... Bristol...... Glasgow ve Plymouth... Dublin...... Sheffield ... Swansea ... Southamp- ton. Southport Presidents Secretaries Sir R.I. Murchison, G.C.St.8.,]R. Cull, Francis Galton, P. O’Cal- laghan, Dr. Norton Shaw, Thomas Wright. Rear - Admiral Sir James|Richard Cull, Prof, Geddes, Dr. Nor- €lerk Ross, D.C.L., F.R.S. ton Shaw. Sir R. I. Murchison, D.C.L.,|Capt. Burrows, Dr. J. Hunt, Dr. C. F.R.S. Lempriére, Dr. Norton Shaw. John Crawfurd, F.R.S.......... Dr. J. Hunt, J. Kingsley, Dr. Nor- ton Shaw, W. Spottiswoode. Francis Galton, F.R.S.......... J.W.Clarke, Rev. J.Glover, Dr. Hunt, Dr. Norton Shaw, T. Wright. Sir R. I. Murchison, K.C.B.,|C. Carter Blake, Hume Greenfield, F.R.S. C. R. Markham, R. §. Watson. Sir R. I. Murchison, K.C.B.,]H. W. Bates, C. R. Markham, Capt. F.R.S. R. M. Murchison, T. Wright. Major-General Sir H. Raw-|H. W. Bates, S. Evans, G. Jabet, C. linson, M.P., K.C.B., F.R.S.| R. Markham, Thomas Wright. Sir Charles Nicholson, Bart.,]H. W. Bates, Rev. E. T. Cusins, R. LL.D. H. Major, Clements R. Markham, D. W. Nash, T. Wright. ...|Sir Samuel Baker, F.R.G.S. |H. W. Bates, CyrilGraham, Clements R. Markham, 8S. J. Mackie, R. Sturrock. Capt. G. H. Richards, R.N.,|/T. Baines, H. W. Bates, Clements R F.R.S. Markham, T. Wright. SECTION E (continued ).—GEOGRAPHY. Sir Bartle’ Frere, K.C.B.,|H. W. Bates, Clements R. Markham, LL.D., F.R.G.S. J. H. Thomas, Sir R. I. Murchison, Bt.,K.C.B.,|H.W.Bates, David Buxton, Albert J. LL.D.,D.C.L., F.R.8., F.G.8.| Mott, Clements R. Markham. Colonel Yule, C.B., F.R.G.S. |A. Buchan, A. Keith Johnston, Cle- ments R. Markham, J. H. Thomas, Francis Galton, F.R.S..........|H. W. Bates, A. Keith Johnston, Rev. J. Newton, J. H. Thomas. Sir Rutherford Alcock, K.C.B.}H. W. Bates, A. Keith Johnston, Clements R. Markham, Major Wilson, R.E., F.R.S.,|E.G. Ravenstein, E. C. Rye, J. H, F.R.G.S. Thomas, Lieut. - General Strachey,,H. W. Bates, E. C. Rye, Hore: R.E.,C.S.L,F.R.S., F.R.G.S.,| Tuckett. F.L.S., F. G. s. .|Capt. Evans, C.B., F.B.S.......)H. W. Bates, E. C. Rye, R. Oliphant Wood. Adm. Sir E. Ommanney, C.B.,|H. W. Bates, F. E. Fox, E. C. Rye. E.R.S., F.R.G.S., F.R.A.S. Prof. Sir C. Wyville Thom-|John Coles, E. C. Rye. son, LL.D., F.R.S.L.&E. Clements R. Markham, C.B.,|H. fu Bates, C. E. D. Black, E. C, F.R.S., Sec. R.G.S. Lieut. -Gen. Sir J. H. Lefroy,|H. aL ‘Bates, E. C. Rye. C.B.,K.C.M.G., R.A., F.R.S., F.RGS. Sir J. D. Hooker, K.C.S.I.,|J. W. Barry, H. W. Bates. C.B., F.R.S. Sir R. Temple, Bart., G.C.S.1.,| E. G. Ravenstein, E. C. Rye. F.R.G.S. Lieut.-Col. H. H. Godwin-| John Coles, E. G. Ravenstein, E. C, Austen, F.R.S. Rye. liv REPORT— 1886. Date and Place Presidents Secretaries 1884. Montreal ...|Gen. Sir J. H. Lefroy, C.B.,| Rev. Abbé Laflamme, J.S. O'Halloran, K.C.M.G., F.R.S.,V.P.8.G.8. E. G. Ravenstein, J. F. Torrance 1885. Aberdeen...|Gen. J. T. Walker, C.B., R.E.,|J. 8. Keltie, J. 8. O'Halloran, E. G. LL.D., F.R.S. Ravenstein, Rey. G. A. Smith. 1886. Birmingham) Maj.-Gen. Sir. F. J. Goldsmid,|F. T. S. Houghton, J. S. Keltie, | K.C.S.1., 0.B., F.R.G.S. E. G. Ravenstein. STATISTICAL SCIENCE. 4 COMMITTEE OF SCIENCES, VI.—STATISTICS. 1833. Cambridge, Prof. Babbage, F.R.S. .........;J. E. Drinkwater. 1834, Edinburgh | Sir Charles Lemon, Bart....... Dr. Cleland, C. Hope Maclean. SECTION F.—STATISTICS. 1835. Dublin...... Charles Babbage, F.R.S. ......| W. Greg, Prof. Longfield. 1836. Bristol...... Sir Chas. Lemon, Bart., F.R.S.|Rev. J. E. Bromby, C. B. Fripp, James Heywood. 1837. Liverpool...| Rt. Hon. Lord Sandon......... W. R. Greg, W. Langton, Dr, W. C. Tayler. 1838. Newcastle |Colonel Sykes, F.R.S. .........| W. Cargill, J. Heywood, W.R. Wood. 1839. Birmingham| Henry Hallam, F.R.S..........| F. Clarke, R. W. Rawson, Dr. W. C. Tayler. 1840, Glasgow ...| Rt. Hon. Lord Sandon, M.P.,|/C. R. Baird, Prof. Ramsay, R. W. F.R.S. Rawson. 1841. Plymouth...| Lieut.-Col. Sykes, F.R.S....... Rev. Dr. Byrth, Rev. R. Luney, R. W. Rawson. 1842. Manchester |G. W. Wood, M.P., F.L.S. ...|Rev. R. Luney, G. W. Ormerod, Dr. W. C. Tayler. 1843. Cork......... Sir C. Lemon, Bart., M.P. ...| Dr. D. Bullen, Dr. W. Cooke Tayler. 1844, York......... Lieut.-Col. Sykes, F.R.S.,|J. Fletcher, J. Heywood, Dr. Lay- E.L.S. cock, 1845. Cambridge | Rt. Hon. the Earl Fitzwilliam | J. Fletcher, Dr. W. Cooke Tayler. 1846. Southamp- |G. R. Porter, F.R.S. ............ J. Fletcher, F. G. P. Neison, Dr. W. ton. C. Tayler, Rev. T. L. Shapcott. 1847. Oxford...... Travers Twiss, D.C.L., F.R.S.| Rev. W. H. Cox, J. J. Danson, F. G. P. Neison. 1848. Swansea ...|J. H. Vivian, M.P., F.R.S. ...|/J. Fletcher, Capt. R. Shortrede. 1849, Birmingham] Rt. Hon. Lord Lyttelton...... Dr. Finch, Prof. Hancock, F. G. P. Neison. 1850. Edinburgh |Very Rev. Dr. John Lee,|Prof. Hancock, J. Fletcher, Dr. J. V.P.R.S.E. Stark. 1851. Ipswich ...|Sir John P. Boileau, Bart. ...|J. Fletcher, Prof. Hancock. 1852. Belfast...... His Grace the Archbishop of} Prof. Hancock, Prof. ngram, James Dublin. MacAdam, jun. 185d, hol... enn James Heywood, M.P., F.R.S.|Edward Cheshire, W. Newmarch. 1854. Liverpool...}Thomas Tooke, F.R.S. .........| E. Cheshire, J. T. Danson, Dr. W. H. Duncan, W. Newmarch. 1855. Glasgow ...|R. Monckton Milnes, M.P. ...| J. A. Campbell, E. Cheshire, W. New- march, Prof. R. H. Walsh. SECTION F (continued).—ECONOMIC SCIENCE AND STATISTICS. 1856. Cheltenham| Rt. Hon. Lord Stanley, M.P. | Rev. C. H. Bromby, E. Cheshire, Dr. W. N. Hancock, W. Newmarch, W. M. Tartt. i857. Dublin...2:. His Grace the Archbishop of| Prof. Cairns, Dr. H. D. Hutton, W. Dublin, M.R.LA. Newmarch. 1858. Leeds ....... Edward Baines......... eattescs T. B. Baines, Prof. Cairns, 8. Brown, Capt. Fishbourne, Dr. J. Strang. a PRESIDENTS AND SECRETARIES OF THE SECTIONS. Date and Place 1859. Aberdeen... 1860. Oxford...... 1861. Manchester 1862. Cambridge 1863. Newcastle 1864. Bath......... 1865. Birmingham 1866. Nottingham 1867. Dundee ..... 1868. Norwich... 1869. Exeter...... 1870. Liverpool... 1871. Edinburgh 1872. Brighton... 1873. Bradford ... 1874. Belfast...... 1875. Bristol...... 1876. Glasgow ... 1877. Plymouth... 1878. Dublin...... 1879. Sheffield ... 1880. Swansea ... 1881. York......... 1882. Southamp- ton. 1883. Southport 1884. Montreal ... 1885. Aberdeen... 1886. Birmingham 1836. Bristol...... 1837. Liverpool... 1838. Newcastle Presidents Secretaries Col. Sykes, M.P., F.R.S. «2.4 Nassau W. Senior, M.A. ...... William Newmarch, F.R.S.... Edwin Chadwick, C.B. ........ -| William Tite, M.P., F.R.S.... William Farr, M.D., D.C.L., F.R.S. Rt. Hon. Lord Stanley, LL.D., M.P. Prof. J. HE. T. Rogers......2..00+ M. E. Grant Duff, M.P. ....... Samuel Brown, Pres. Instit. Actuaries. Rt. Hon. Sir Stafford H. North- cote, Bart., C.B., M.P. Prof. W. Stanley Jevons, M.A. Rt. Hon. Lord Neaves......... Prof. Henry Fawcett, M.P.... Rt. Hon. W. E. Forster, M.P. Lord) O€a@o-aar't 1. ceeccd. .ae2. James Heywood, M.A.,F.R.S., Pres.§.8. Sir George Campbell, K.C.S.L, M.P Rt. Hon. the Earl Fortescue Prof. J. K. Ingram, LL.D., M.R.I1A. G. Shaw Lefevre, M.P., Pres. 8.8. G. W. Hastings, M.P........... Rt. Hon. M. E. Grant-Duff, M.A., F.R.S. Rt. Hon. G. Sclater-Booth, M.P., F.B.S. R. H. Inglis Palgrave, F.R.S. Sir Richard Temple, Bart., G.C.S.I., C.LE., F.R.G.S. Prof. H. Sidgwick, LL.D., Litt.D. J. B. Martin, M.A., F.S.S. Prof. Cairns, Edmund Macrory, A. M, Smith, Dr. John Strang. Edmund Macrory, W. Newmarch, Rev. Prof. J. E. T. Rogers. | David Chadwick, Prof. R. C. Christie, E. Macrory, Rev. Prof. J. E. T. Rogers. H. D. Macleod, Edmund Macrory. |T. Doubleday, Edmund Macrory Frederick Purdy, James Potts. E. Macrory, E. T. Payne, F. Purdy. G. J. D. Goodman, G. J. Johnston, E. Macrory. R. Birkin, jun., Prof. Leone Levi, E. Macrory. Prof. Leone Levi, E. Macrory, A. J. Warden. Rev. W.C. Davie, Prof. Leone Levi. Edmund Macrory, Frederick Purdy, Charles T. D. Acland. ; : Chas. R. Dudley Baxter, E. Macrory, J. Miles Moss. J. G. Fitch, James Meikle. J. G. Fitch, Barclay Phillips. J. G. Fitch, Swire Smith. Prof. Donnell, Frank P. Fellows, Hans MacMordie. F. P. Fellows, T. G. P. Hallett, E. Macrory. A. M‘Neel Caird, T.G. P. Hallett, Dr. W. Neilson Hancock, Dr. W. Jack. W. F. Collier, P. Hallett, J. T. Pim. W. J. Hancock, C. Molloy, J. T. Pim. Prof. Adamson, R. E. Leader, C. Molloy. N. A. Humphreys, C. Molloy. C. Molloy, W. W. Morrell, J. F. Moss. G. Baden-Powell, Prof. H. S. Fox- well, A. Milnes, C. Molloy. Rev. W. Cunningham, Prof. H. S. Foxwell, J. N. Keynes, C. Molloy. Prof. H. 8. Foxwell, J.S. McLennan, Prof. J. Watson. Rev. W. Cunningham, Prof. H. 8. Foxwell, C. McCombie, J. F. Moss. F. F. Barham, Rey. W. Cunningham, Prof. H. S. Foxwell, J. F. Moss. MECHANICAL SCIENCE. SECTION G.—MECHANICAL SCIENCE. Davies Gilbert, D.C.L., F.B.S. Rev. Dr. Robinsor ............ Charles Babbage, F.R.5....... (I. G. Bunt, G. T. Clark, W. West. Charles Vignoles, Thomas Webster. R. Hawthorn, C. Vignoles, T.. Webster. lvi REPORT—1 886, Date and Place Presidents Secretaries 1839. Birmingham | Prof. Willis, F.R.S.,and Robt.| W. Carpmael, William Hawkes, T, 1840. Glasgow .... 1841. Plymouth 1842. Manchester 1843. Cork......... 1844. York......... 1845. Cambridge 1846, Southamp- ton. 1847. Oxford...... 1848. Swansea 1849, Birmingham 1850. Edinburgh 1851. Ipswich ..... 1852. Belfast...... 1853. Hull......... 1854, Liverpool... 1855. Glasgow ... 1856. Cheltenham 1857. Dublin...... 1858. Leeds ...... 1859. Aberdeen... 1860. Oxford ...... 1861. Manchester 1862. Cambridge 1863, Newcastle 1864. Bath......... 1865. Birmingham 1866. Nottingham 1867. Dundee...... 1868. Norwich ... 1869. Exeter ...... 1870. Liverpool... 1871. Edinburgh 1872. Brighton ... 1873. Bradford ... 1874, Belfast...... Stephenson. Webster. Sir John Robinson ............. J. Scott Russell, J. Thomson, J. Tod, C. Vignoles. John Taylor, F.R.S. ............| Henry Chatfield, Thomas Webster. Rev. Prof, Willis, F.R.S. ......|J. F. Bateman, J. Scott Russell, J, Thomson, Charles Vignoles. Prof, J. Macneill, M.R.LA....| James Thomson, Robert Mallet. JOMNULAVLON, HB Ssiccceeec cs as Charles Vignoles, Thomas Webster, George Rennie, F.R.S.......... Rev. W. T. Kingsley. Rey. Prof. Willis, M.A., F.R.S.| William Betts, jun., Charles Manby, Rey. Prof.Walker, M.A.,F.R.S.| J. Glynn, R. A. Le Mesurier. ...| Rev. Prof.Walker, M.A.,F.R.S.| R. A. Le Mesurier, W. P. Struvé. Robt. Stephenson, M.P., F.R.S.| Charles Manby, W. P. Marshall. Rey. RegROINSON ...cccacscsess Dr. Lees, David Stephenson. William Cubitt, F.R.S.......... John Head, Charles Manby. John Walker, C.E., LL.D.,|John F. Bateman, C. B Hancock, F.R.S. Charles Manby, James Thomson. William’ Fairbairn, C.E.,|James Oldham, J. Thomson, W. F.R.S. Sykes Ward. John Scott Russell, F.R.S. ...|John Grantham, J. Oldham, J, Thomson. W. J. Macquorn Rankine,|L. Hill, jun., William Ramsay, J. C.E., F.R.S. Thomson. George Rennie, F.R.S..........]C. Atherton, B. Jones, jun., H. M, Jeffery. Rt. Hon. the Earl of Rosse,| Prof. Downing, W.T. Doyne, A. Tate, F.R.S. James Thomson, Henry Wright. William Fairbairn, F.R.S. ...| J. C. Dennis, J. Dixon, H. Wright. Rey. Prof. Willis, M.A., F.R.S.|R. Abernethy, P. Le Neve Foster, H, Wright. Prof. W.J. Macquorn Rankine, | P. Le Neve Foster, Rev. F. Harrison, LL.D., F.R.S. Henry Wright. J. F. Bateman, C.E., F.R.S....|P. Le Neve Foster, John Robinson, H. Wright. Wm. Fairbairn, LL.D., F.R.S.|W. M. Fawcett, P. Le Neve Foster. Rey. Prof. Willis, M.A., F.R.S.|P. Le Neve Foster, P. Westmacott, J. F. Spencer. J. Hawkshaw, F.R.S. .........]P. Le Neve Foster, Robert Pitt. Sir W. G. Armstrong, LL.D.,|P. Le Neve Foster, Henry Lea, W. F.R.S. P. Marshall, Walter May. Thomas Hawksley, V.P.Inst.|P. Le Neve Foster, J. F. Iselin, M. C.E., F.G.S. O. Tarbotton. ; Prof.W.J. Macquorn Rankine,|P. Le Neve Foster, John P, Smith, LL.D., F.R.S. W. W. Urquhart. G. P. Bidder, C.E., F.R.G.S. |P. Le Neve Foster, J. F. Iselin, C. Manby, W. Smith. C. W. Siemens, F.R.S..........}P. Le Neve Foster, H. Bauerman. Chas. B. Vignoles, C.E., F.R.S.|H. Bauerman, P. Le Neve Foster, T, King, J. N. Shoolbred. Prof, Fleeming Jenkin, F.R.S.|H. Bauerman, Alexander Leslie, J. P. Smith. F, J. Bramwell, C.E. ......... H. M. Brunel, P. Le Neve Foster, J. G. Gamble, J. N. Shoolbred. W. H. Barlow, F.R.S. .........]Crawford Barlow, H. Bauerman, E. H. Carbutt, J. C. Hawkshaw, J. N. Shoolbred. Prof. James Thomson, LL.D.,|A. T. Atchison, J. N. Shoolbred, John C.E., F.R.S.E. Smyth, jun. PRESIDENTS AND SECRETARIES OF THE SECTIONS. lyti nn ——————————— EE Date and Place Presidents . Secretaries 1875. Bristol ...... W. Froude, C.E., M.A., F.R.S.|W. R. Browne, H. M. Brunel, J. G. Gamble, J. N. Shoolbred. 1876. Glasgow ...|C. W. Merrifield, F.R.S. ......|W. Bottomley, jun., W. J. Millar, J. N. Shoolbred, J. P. Smith. 1877. Plymouth...| Edward Woods, C.E. ......... A. T. Atchison, Dr. Merrifield, J. N. Shoolbred. 1878. Dublin...... Edward Easton, C.E. ......... A. T. Atchison, R. G. Symes, H. T. Wood. 1879. Sheffield ...|J. Robinson, Pres. Inst. Mech.| A. T. Atchison, Emerson Bainbridge, Eng. H. T. Wood. 1880. Swansea ...|James Abernethy, V.P. Inst.|A. T. Atchison, H. T. Wood. C.E., F.R.S.E. Meeks YOrK......00. Sir W. G. Armstrong, C.B.,{A. T. Atchison, J. F. Stephenson, LL.D., D.C.L., F.R.S. H. T. Wood. 1882. Southamp- | John Fowler, C.E., F.G.S. ...|A. T. Atchison, F. Churton, H. T. ton. Wood. 1883. Southport |James Brunlees, F.R.S.E.,|A. T. Atchison, E. Rigg, H. T. Wood. 1884. 1885. 1886. 1884. 1885. 1886. Pres.Inst.C.E. Montreal ...|Sir F. J. Bramwell, F.R.S.,]A. T. Atchison, W. B. Dawson, J- V.P.Inst.C.E. Kennedy, H. T. Wood. Aberdeen...|B. Baker, M.Inst.C.E. .........|A. T. Atchison, F. G. Ogilvie, E. Rigg, J. N. Shoolbred. Birmingham|Sir J. N. Douglass, M.Inst.|C. W. Cooke, J. Kenward, W. B. C.E. Marshall, E. Rigg. ANTHROPOLOGICAL SCIENCE. SECTION H.—ANTHROPOLOGY. Montreal... |E. B. Tylor, D.C.L., F.R.S....|G. W. Bloxam, W. Hurst. Aberdeen.../| Francis Galton, M.A., F.R.S. |G. W. Bloxam, Dr. J. G. Garson, W. Hurst, Dr. A. Macgregor. Birmingham|Sir G. Campbell, K.C.S.I.,]G. W. Bloxam, Dr. J. G. Garson, W. . M.P., D.C.L., F.R.G.S. Hurst, Dr. R. Saundby LIST OF EVENING LECTURES. Date and Place Lecturer Subject of Discourse 1842. 1843. 1844, 1845. 1846. Manchester | Charles Vignoles, F.R.S...... |The Principles and Construction of Atmospheric Railways. Siri Mole Bone!) §l5.c:. senses The Thames Tunnel. Roa! Murchison, ...cc.sc.ss-nsee The Geology of Russia. Work io. seices Prof. Owen, M.D., F.R.S....... The Dinornis of New Zealand. Prof. E. Forbes, F.R.S..........]|The Distribution of Animal Life in the Aigean Sea. DrARODINSOMN.. 1... cece endocecees The Earl of Rosse’s Telescope. BVOLK si ccseess Charles Lyell, F.R.S. .........]Geology of North America. Dr. Falconer, F.R.S.............| The Gigantic Tortoise of the Siwalik Hills in India. Cambridge |G.B.Airy,F.R.S.,Astron.Royal| Progress of Terrestrial Magnetism. R. I. Murchison, F.R.S. ......|Geology of Russia. Southamp- | Prof. Owen, M.D., F.R.S. ...| Fossil Mammaliaof the British Isles. ton, Charles Lyell, F.B.S. .........| Valley and Delta of the Mississippi. W. R. Grove, F.R.S....... «+++. | Properties of the Explosivesubstance discovered by Dr. Schénbein; also some Researches of his own on the Decomposition of Water by Heat, lviii Date and Place 1847. 1848. 1849. 1850. 1851. 1852. 1853. 1854. 1855. 1856. 1857. 1858, 1859. 1860. 1861. 1862. 1863. 1864. Oxford Swansea ... Birmingham Edinburgh Ipswich ... Belfast...... Liverpool... Glasgow ... Cheltenham ee eene Manchester Cambridge Newcastle REPORT—1886. Lecturer Subject of Discourse Rev. Prof. B. Powell, F.R.S. Prof. M, Faraday, F.R.S....... Hugh E. Strickland, F.G.S.... John Percy, M.D., F.R.S....... W. Carpenter, M.D., F.R.S.... Dr. Haradays HHS: ..sccc.cce5c Rey. Prof. Willis, M.A., F.R.S. Prof. J. H. Bennett, M.D., F.R.S.E. Drs Mantel sR URIS. i. ccecsn vas Prof. R. Owen, M.D., F.R.S. G.B.Airy,F.R.S.,Astron. Royal Prof. G. G. Stokes, D.C.L., F.R.S. Colonel Portlock, R.E., F.R.S. Prof, J. Phillips, LL.D., F.R.S., F.G.8. Robert Hunt, F.R.S............. Prof. R. Owen, M.D., F.R.S. Col. EH. Sabine, V.P.R.S. ...... Dr. W. B. Carpenter, F.R.S. Lieut.-Col. H. Rawlinson Col. Sir H. Rawlinson se eeeeene WasiGrove, BUR-S., .:..cscesnt Prof. W. Thomson, F.R.S. ... Rey. Dr. Livingstone, D.C.L. Prof. J. Phillips, LL.D.,F.R.S. Prof. R. Owen, M.D., F.R.S. Sir R. I. Murchison, D.C.L.... Rey. Dr. Robinson, F.R.S. ... Rev. Prof. Walker, F.R.S. ... Captain Sherard Osborn, R.N. Prof.W.A. Miller, M.A., F.R.S. G.B.Airy,F.R.S.,Astron. Royal Prof. Tyndall, LL.D., F.R.S8. Prof. Odling, F.R.S............. Prof. Williamson, F.R.S....... James Glaisher, F.R.S......... Prof. Roscoe, F.RB.S. ............ Dr. Livingstone, F.R.S. .... Shooting Stars. Magnetic and Diamagnetic Pheno- mena. The Dodo (Didus ineptus). Metallurgical Operations of Swansea and its neighbourhood. Recent Microscopical Discoveries. Mr. Gassiot’s Battery. Transit of different Weights with varying velocities on Railways. Passage of the Blood through the minute vessels of Animals in con- nexion with Nutrition. Extinct Birds of New Zealand, Distinction between Plants and Animals, and their changes of Form. Total Solar Eclipse of July 28, 1851. Recent discoveries in the properties of Light. Recent discovery of Rock-salt at Carrickfergus, and geological and practical considerations connected with it. Some peculiar Phenomena in the Geology and Physical Geography of Yorkshire. The present state of Photography. Anthropomorphous Apes. Progress of researches in Terrestrial Magnetism. Characters of Species. .| Assyrian and Babylonian Antiquities and Ethnology. Recent Discoveries in Assyria and Babylonia, with the results of Cuneiform research up to the present time. Correlation of Physical Forces. The Atlantic Telegraph. Recent Discoveries in Africa. The Ironstones of Yorkshire. The Fossil Mammalia of Australia. Geology of the Northern Highlands. Electrical Discharges in highly rarefied Media. Physical Constitution of the Sun. Arctic Discovery. Spectrum Analysis. The late Eclipse of the Sun. The Forms and Action of Water. Organic Chemistry. The Chemistry of the Galvanic Bat- | tery considered in relation to Dynamics. The Balloon Ascents made for the British Association. The Chemical Action of Light. ‘Recent Travels in Africa. a ee ee ae LIST OF EVENING LECTURES. lix Date and Place 1865. Birmingham|J. Beete Jukes, F.R.S...... 1866. Nottingham 1867. Dundee...... 1868. Norwich ... 1869. Exeter 1870. Liverpool... 1871. Edinburgh 1872. Brighton ... 1873. Bradford ... 1874. Belfast ...... 1875. Bristol ...... 1876. Glasgow ... 1877. Plymouth... 1878. Dublin seeeee 1879. 1880. Swansea ... Sheffield ... 1881. York......... 1882. Southamp- ton. 1883. Southport Lecturer é William Huggins, F.R.S. Dr. J. D. Hooker, F.R.S...... Archibald Geikie, F.R.S....... Alexander Herschel, F.R.A.S. J. Fergusson, F.R.S............. Dr. W.. Odling, HR.S: .25<0<.;. Prof. J. Phillips, LL.D.,F.R.S. J. Norman Lockyer, F.R.S.... Prof. J. Tyndall, LL.D., F.R.S. Prof.W.J. Macquorn Rankine, LL.D., F.R.S. iM. A. Abel pienisSi..ch.0s..592ee See eaeseeeee E. B. Tylor, F.R.S. Prof. P. Martin Duncan, M.B., F.R.S. Prof. W. K. Clifford............ Prof. W. C.Williamson, F.R.S. Prof, Clerk Maxwell, F.R.S. Sir John Lubbock, Bart.,M.P., F.R.S. Prof. Huxley, F.R.S. ......... W.Spottiswoode,LL.D.,F.R.S. F. J. Bramwell, F.R.S.......... Prof. Tait, F.R.S.E. Sir Wyville Thomson, ¥F R. s. W. Warington Smyth, M.A., F.RB.S. Prof. Odling, F.R.S............. G. J. Romanes, F'.L:S. ......... Prof. Dewar, F.R.S.............. W. Crookes, F'.B.S. ........000. Prof. E. Ray Lankester, F.R.S. Prof. W. Boyd Dawkins, F.R.S. Francis Galton, F.R.S.......... Prof. Huxley, Sec. R.S. W. Spottiswoode, Pres. R.S. Prof. Sir Wm. Thomscn, F.R.S. Prof. H. N. Moseley, F.R.S. Profs Ra 5: Ball eR.S. css... Prof. J. G. McKendrick, F.R.S.E. ‘ Subject of Discourse ....| Probabilities as to the position and extent of the Coal-measures be- neath the red rocks of the Mid- land Counties. -|The results of Spectrum Analysis applied to Heavenly Bodies. .|Insular Floras. The Geological Origin of the present Scenery of Scotland. The present state of knowledge re- garding Meteors and Meteorites. Archeology of the early Buddhist Monuments. Reverse Chemical Actions. Vesuvius. The Physical Constitution of the Stars and Nebule. The Scientific Use of the Imagination. Stream-lines and Waves, in connec- tion with Naval Architecture. Some recent investigations and ap- plications of Explosive Agents. The Relation of Primitive to Modern Civilization. Insect Metamorphosis. The Aims and Instruments of Scien- tific Thought. Coal and Coal Plants. Molecules, Common Wild Flowers considered in relation to Insects. The Hypothesis that Animals are Automata, and its History. The Colours of Polarized Light. Railway Safety Appliances. ..| Force. The Challenger Expedition. The Physical Phenomena connected with the Mines of Cornwall and Devon. The new Element, Gallium. Animal Intelligence. Dissociation, or Modern Ideas of Chemical Action. Radiant Matter. Degeneration. Primeval Man. Mental Imagery. The Rise and Progress of Palzon- tology. The Electric Discharge, its Forms and its Functions. Tides. Pelagic Life. Recent Researches on the Distance of the Sun. Galvani and Animal Electricity. lx REPORT—1886. Date and Place 1884. 1885. Aberdeen... 1886, Birmingham |A. W. Riicker, M.A., F.R.S. 1867. 1868. 1869. 1870. 1872, 1872. 1874, 1875. 1876. 1877. 1879. 1880. 1881, 1882. 1883. 1884. 1885. Montreal... Lecturer Subject of Discourse Prof. O. J. Lodge, D.Sc. ...... Dust. Rev. W. H, Dallinger, F.R.S. |The Modern Microscope in Re- searches on the Least and Lowest Forms of Life. The Electric Light and Atmospheric Absorption. The Great Ocean Basins. Soap Bubbles. The Sense of Hearing. Prof. W. G. Adams, F.R.S. ... John Murray, F.R.S.E.......... Prof. W. Rutherford, M.D.... LECTURES TO THE OPERATIVE CLASSES. Dundee...... Norwich ... Exeter Liverpool... Brighton ... Bradford ... Belfast eeeees Plymouth... Sheffield ... Swansea ... York Southport Montreal ... Aberdeen... Prof. J. Tyndall, LL.D., F.R.S.| Matter and Force. Prof. Huxley, LL.D., F.R.S. |A Piece of Chalk. Prof. Miller, M.D., F.R.S. ...|Experimental illustrations of the modes of detecting the Composi- tion of the Sun and other Heavenly Bodies by the Spectrum, Sir John Lubbock, Bart.,M.P.,] Savages, F.R.S. W.Spottiswoode,LL.D.,F.R.S.| Sunshine, Sea, and Sky. C. W. Siemens, D.C.L., F.R.S.| Fuel. Prof. Odling, F.R.S.........+00 The Discovery of Oxygen. Dr. W. B. Carpenter, F.R.S. |A Piece of Limestone. ...|Commander Cameron, C.B.,)A Journey through Africa, R.N. We Hs Preecetss.te.seccecssssaeee Telegraphy and the Telephone. Wie HiscAE GON sesccceesetoecss Electricity as a Motive Power. H. Seebohm, F.Z.S. .........06 The North-East Passage, Prof. Osborne Reynolds,| Raindrops, Hailstones, and Snow- F.R.S. flakes. John Evans, D.C.L. Treas.R.S.| Unwritten History, and how to read it. Sir F. J. Bramwell, F.R.S. ...| Talking by Electricity—Telephones, Prof. R. 8. Ball, F.R.S..........| Comets. H. B. Dixon, M.A. The Nature of Explosions. wee e eee eeeee 1886. Birmingham|Prof. W. C. Roberts-Austen,}The Colours of Metals and their F.R.S. Alloys. lsi OFFICERS OF SECTIONAL COMMITTEES PRESENT AT THE BIRMINGHAM MEETING. SECTION A.—MATHEMATICAL AND PHYSICAL SCIENCE. President.—Professor G. H. Darwin, M.A., LL.D., F.R.S., F.R.A.S. Vice-Presidents——Sir R. 8. Ball, F.R.S.; Professor Cayley, F.R.S.; Donald MacAlister, M.D.; Lord Rayleigh, Sec.R.S.; Professor Stokes, Pres.R.S. ; Rev. H. W. Watson, F.R.S. ° Secretaries.—R. HE. Baynes, M.A. (Recorder); R. T. Glazebrook, F.R.S. ; Professor J. H. Poynting, M.A.; W. N. Shaw, M.A. SECTION B.—CHEMICAL SCIENCE. ~ President.—William Crookes, F.R.S., V.P.C.S. Vice-Presidents.—Professor Thomas Carnelley, D.Sc. ; Dr. W. H. Perkin, F.R.S.; Professor H. E. Armstrong, F.R.S.; Dr. J. H. Gladstone, F.R.S.; A. G. Vernon Harcourt, F.R.S.; Sir Henry E. Roscoe, F.R.S.; Dr. W. J. Russell, F.R.S.; Professor W. A. Tilden, F.R.S. ; Professor A. W. Williamson, F.R.S. Secretaries.—Professor P. Phillips Bedson, D.Sc. (Recorder); H. B. Dixon, F.R.S.; H. Forster Morley, D.Sc.; W. W. J. Nicol, D.Sc. - C. J. Woodward, B.Sc. SECTION C.— GEOLOGY. President.—Professor T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S, Vice-Presidents—Rev. H. W. Crosskey, LL.D.; Sir Julius von Haast, K.C.M.G., F.R.S.; Professor EH. Hull, F.R.S.; Professor (. Lap- worth, LU.D.; W. Mathews, M.A.; Dr. A. R. Selwyn, C.M.G., F.R.S. ; H. Woodward, F.R.S. Secretaries—W. Jerome Harrison, F.G.S.; J. J. H. Teall, F.G.S.; W. Topley, F.G.S. (Recorder) ; W. W. Watts, F.G.S. SECTION D.—BIOLOGY. President.—William Carruthers, Pres.L.S., F.R.S., F.G.S. Vice-Presidents.—Professor E. A. Schifer, F.R.S.; P. L. Sclater, F.R.S. ; Professor Michael Foster, Sec.R.S.; Professor Alfred Newton,F.R.S.; Dr. Henry Trimen; Professor W. C. Williamson, F.R.S. Secretaries Professor T. W. Bridge, M.A.; Walter Heape (Recorder) ; Professor W. Hillhouse, M.A.; W. L. Sclater, B.A.; Professor H. Marshall Ward, M.A. xii * REPORT—1886. SECTION E.—GEOGRAPHY. President.—Major-General Sir F. J. Goldsmid, K.C.S.1, C.B., F.R.G.S. Vice-Presidents.—H. W. Bates, F.R.S. ; Admiral Sir E. Ommanney, C.B., F.R.S.; Major-General Sir Lewis Pelly, K.C.B., M.P.; Colonel Sir Lambert Playfair, K.C.M.G.; General J. T. Walker, C.B., F.R.S.; Captain W. J. L. Wharton, R.N., F.R.S.; Colonel Sir Charles Wilson, K.C.B., F.R.S. Secretaries.—F. T. S. Houghton, M.A.; J. S. Keltie; E.G. Ravenstein (Recorder). SECTION F.—ECONOMIC SCIENCE AND STATISTICS. President—J. B. Martin, M.A., F.S.S8., F.Z.S. Vice-Presidents—G. W. Hastings, M.P.; Sir Richard Temple, Bart., G.C.S.1., M.P.; Sir Rawson W. Rawson, K.C.M.G., C.B.; . Hyde Clarke, F.S.S. Secretaries—F. F. Barham; Rev. W. Cunningham, D.Sc. (Recorder) ; Professor H. S. Foxwell, M.A. ; J. F. Moss. SECTION G.-—MECHANICAL SCIENCE. President.—Sir James N. Douglass, M.Inst.C.E. Vice-Presidents—W. Anderson ; Professor H. T. Bovey, M.A.; Sir Frederick Bramwell, F.R.S.; W. P. Marshall; Professor R. H. Smith ; Edward Woods, Pres.Inst.C.E. Secretaries.—Conrad W. Cooke; J. Kenward; W. Bayley Marshall ; Edward Rigg, M.A. (Recorder). SECTION H.—ANTHROPOLOGY. President.—Sir George Campbell, K.C.S.1., M.P., D.C.L., F.R.G.S. Vice-Presidents—Professor W. Boyd Dawkins, F.R.S.; W. Pengelly, F.R.S. ; Colonel Sir Charles Wilson, K.C.B., F.R.S. Secretaries—G. W. Bloxam, M.A. (Recorder); J. G, Garson, M.D.; Walter Hurst, B.Sc.; R. 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Seen, Ore “Yelk Ok re Fo 2 eee eS Se ee ‘HONAIOS JO LNAWHONVAGY AHL YOAL NOLLVIOOSSV HSILIdd AHL * =" lxiv Date of Meeting 11831, Sept. 27 ... 1832, June 19... 1833, June 25... es] HOinburoh |...c. lee Fie oe 981 12 8 | 1844 94 22 407 172 35 MOTD) Ao ae ceeese 831 9 9 | 1845 65 39 270 196 36 SBT of iaoasts cats 685 16 0 | 1846 197 40 495 203 53 E390 | secadane 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 0 159 19 6 | 1849 128 ” 42 510 273 44 1241 1085 0 0 345 18 0 | 1850 . 61 47 244 141 37 710 620 0 0 Sole OF | 18b1 63 60 510 292 9 1108 1085.0 0 304 6 7 | 1852 | 56 57 367 236 6 876 903 0 0 205 0 O| 1853 121 121 765 524 10 1802 1882 0 0 380 19 7 | 1854 142 101 1094 543 26 2133 2311 0 0 480 16 4 | 1855 104 48 412 346 9 1115 1098 0 0 734 13 9 | 1856 156 120 900 569 26 2022 2015 0 0 507 15 44 | 1857 91 710 509 13 1698 1931 0 0 618 18 2 | 1858 179 1206 821 22 2564 2782 0 0 684 11 1] 1859 59 636 463 47 1689 1604 0 0 766 19 6 | 1860 125 1589 791 15 3138 3944 0 0} 1111 5 10] 1861 57 433 242 25 1161 1089 0 0 | 1293 16 6 | 1862 209 1704 1004 25 3335 3640 0 0] 1608 3 10 | 1863 103 1119 1058 13 2802 2965 0 0] 1289 15 8 | 1864 149 766 508 23 1997 2227 00] 1591 710] 1865 105 960 Cpe 11 2303 2469 0 0] 1750 13 4 | 1866 118 1163 T71 fi 2444 2613 0 0) 1739 4 0 | 1867 117 720 682 45t 2004 2042 001] 1940 O O| 1868 107 678 600 17 1856 1931 0 0 | 1622 0 OO} 1869 195 1103 910 14 2878 3096 0 0] 1572 O O |} 1870 127 976 754 21 2463 2575 00) 1472 2 6) 1871 80 937 912 43 2533 2649 00); 1285 O O| 1872 99 796 601 11 1983 2120 00) 1685 O O| 1873 85 817 630 12 1951 1979 0 0] 1151 16 0} 1874 93 884 672 M7 2248 2397 0 0 960 O O | 1875 185 1265 712 25 2774 3023 00] 1092 4 2 | 1876 59 446 283 11 1229 1268 0011128 9 7 | 1877 93 1285 674 17 2578 2615 0 0 725 16 61 1878 74 529 349 13 1404 1425 0 0 | 1080 11 11 | 1879 41 389 147 12 915 899 0 0 731 7 7) 1880 176 1230 514 24 2557 2689 0 0 476 3 11) 1881 79 516 189 21 1253 1286 0 0] 1126 1 11 | 1882 323 952 841 5 2714 3369 00] 1083 3 3) 1883 219 826 74 26& 60 H.§ 1777 1538 00]1173 4 O|] 1884 122 1053 447 6 2203 2256 00] 1385 O 0 | 1885 179 1067 429 ie 2453 2532 0 0 995 O- 6] 1886 adies were not admitted by purchased Tickets until 1843. t+ Tickets of Admission to Sections only. cluding Ladies. § Fellows of the American Association were admitted as Honorary Members for this Meeting. OFFICERS AND COUNCIL, 1886-87. ; PRESIDENT. SIR J. WILLIAM DAWSON, C.M.G., M.A., LL.D., F.R.S. F.G.S., Principal and Vice-Chancellor of McGill University, Montreal, Canada. VICE-PRESIDENTS. i The Right Hon. the EARL OF BRADFORD, Lord- ; The Rt. Rev. the Lorp BisHop oF WORCESTER, D.D Lieutenant of Shropshire. THOMAS MARTINEAU, Esq., Mayor of Birmingham. The Right Hon. Lorp Lerten, D.C.L., Lord-Lieu- Professor G. G. SroKkes, M.A., D.C.L., LL.D. tenant of Warwickshire. Pres.R.S. The Right Hon. Lorp Norton, K.C.M.G. Professor W. A. TILDEN, D.Se., F.RS., F.C.S The Rigot Hon. Lorp WROTTESLEY, Lord-Lieu- Rey. A. R. VARDY, M.A. tenant of Staffcrdshire. Rey. H. W. Watson, D.Sc., F.R.S PRESIDENT ELECT. SIR H. E. ROSCOE, M.P., LL.D., Ph.D., F.R.S., V.P.C.S, VICE-PRESIDENTS ELECT. His Grace the DUKE oF DEVONSHIRE, K.G., M.A., LL.D., F.R.S., F.G.S., F.R.G.S. The Right Hon. the Earu or Dersy, K.G., M.A., LL.D., F.R.S., F.R.G.S. The Right Rev. the Lornp BisHor OF MANCHESTER, D.D. The Right Rev. the BISHOP OF SALFORD. The Right Worshipful the MAyoGR OF MANCHESTER. The Right Worshipful the MAYOR OF SALFORD. The Vick-CHANCELLOR of Victoria University, Manchester. The PrINcIPAL of Owens College, Manchester. Sir WILLIAM ROBERTS, B.A., M.D., F.R.S. THOMAS ASHTON, Esq., J.P., D.L. OLIVER Heyrwoop, Esq., J.P.. D.L. (nominated by the Council). JAMES PREscoTT JOULE, Esq., D.C.L., LL.D., F.R.S., F.R.S.E., F.C.S. LOCAL SECRETARIES FOR THE MEETING AT MANCHESTER, F. J. FARADAY, Esq., F.L.S., F.S.S. Professor A. MILNES MARSHALL, M.D., D.Se., F.R.S CHARLES HOPKINSON, Esq., B.Sc. Professor A. H, YounG, M.B., F.R.C.S. LOCAL TREASURER FOR THE MEETING AT s¢MANCHESTER Alderman JOSEPH THOMPSON J.P. ORDINARY MEMBERS OF THE COUNCIL. ABNEY, Capt. W. DE W., F.R.S. HAWKSHAW, J. CLARKE, Esq., F.G.S. BALL, Professor Sir R. S., F.R.S. HeEnnricl, Professor O., F.R.S. Bartow, W. H., Esq., F.R.S. JUDD, Professor J. W., F.R.S. BLANFORD, W. T. Esq., F.R.S. M‘LEOD, Professor H., F.R.S. BRAMWELL, Sir F. J., F.R.S. ManRrrTIN, J. B., Esq., F.S.8. CROOKES, W.., Esq., F.R.S. MOSELEY, Professor H. N., F.R.S. DARWIN, Professor G. H., F.R.S. OMMANNEY, Admiral Sir E., C.B., F.R.S. Dawkins, Professur W. Born, F.R.S. PENGELLY, W., Esq., F.R.S. De La Rog, Dr. WARREN, F.R.S. ROBERTS- AUSTEN, Professor W. C., F.R.S. DeEwak, Professor J., F.R.S. TEMPLE, Sir R., Bart., G.C.S.I. FLOWER, Professor W. H., F.R.S. THISELTON-DyeER, W. T., Esq., C.M.G., GLADSTONE, Dr. J. H., F.R.S. E.R.S, GODWIN-AUSTEN, Lieut.-Col. H. H., F.R.S. TuHorpE, Professor T. E., F.R.S. GENERAL SECRETARIES. Capt. Dovetas Gatton, C.B., D.C.L., LL.D., F.R.S., F.G.S., 12 Chester Street, London, S.W. A. G. VERNON Harcourt, Esq., M.A., LL.D., F.R.S., F.C.S., Cowley Grange, Oxford. SECRETARY. ArTHuR T. ATcHISON, Esg., M.A., 22 Albemarle Street, London, W. GENERAL TREASURER. Professor A. W. WILLIAMSON, Ph.D., LL.D., F.R.S., F.C.S., University College, London, W.C. EX-OFFICIO MEMBERS OF THE COUNCIL. The Trustees, the President and President Elect, the Presidents of former years, the Vice-Presidents and Vice-Presidents Elect, the General and Assistant General Secretaries for the present and former years, the Secretary, the General Treasurers for the present and former years, and the Local Treasurer and Secretaries for the ensuing Meeting. TRUSTEES (PERMANENT). Sir Joun Luesock, Bart., M.P., D.C.L., LL.D., F.R.S., Pres. L.S. The Right Hon. Lord RAYr EIGH, M. Be D.C. Tis, LL.D., * Sec.R.S. , F.R.A.S. The Right Hon. Sir Lyon PLAYFAIR, K. C.B. 5 Ps Ph. D., LL.D., F.R.S. PRESIDENTS OF FORMER YEARS. The Duke of Devonshire, K.G. Prof. Stokes, D.C.L., Pres. R.S. Prof. Allman, M.D., F.R.S. Sir G. B. Airy, K.C.B. E.R.S. Prof, Huxley, LL.D., F.R.S8. Sir A. C. Ramsay, LL.D. , FRE The Duke of Argyll, KC G., K.T. | Prof. Sir Wm. Thomson, LL.D. Sir John Lubbock, Bart., FR. s. Sir Richard Owen, K.C.B., F.R.S. | Prof. Williamson, Ph.D., F.R S. Prof. Cayley, LL.D., F. RS. Sir W. G. Armstrong, mot LL.D.| Prof. Tyndall, D.C.L., F.R.S. Lord Rayleigh, D.C Sec.R.S. Sir William R. Grove, F.R.S. Sir John Hawkshaw, F.R.S. Sir Lyon Playfair, K.C.B. Sir Joseph D. Hooker, K.C.S.I. ; GENERAL OFFICERS OF FORMER YEARS. F, Galton, Esq., F.R.S. Dr. Michael Foster, Sec. R.S. P. L. Sclater, Esq., Ph.D., F.R.S. Dr. T. A. Hirst, F.R.S. George Griffith, Esq., M.A., F.C.S. | Prof. Bonney, D.Sc., F.R.S. AUDITORS. John Evans, Esq., D.C.L.,F.R.§. | Dr. W. H. Perkin, F.R.S, | W.H. Preece, Esq.,T.R.S. Se —E_- — Ixvii REPORT OF THE COUNCIL. Report of the Cowncil for the year 1885-86, presented to the General Commuitiee at Birmingham, on Wednesday, September 1, 1886. Tue Council have received reports during the past year from the General Treasurer, and his account for the year will be laid before the General Committee this day. Since the Meeting at Aberdeen the following haye been elected Corresponding Members of the Association :— Professor Putnam. | Dr. Max Schuster. Rey. Dr. Renard. | M. Jules Vuylsteke. As Professor Huxley was unable to accept the office of a Vice-President for the present meeting, the Council have nominated in his stead Professor Stokes, Pres.R.S. The Council have received a letter from Sir Charles Tupper, High Commissioner for the Dominion of Canada, enclosing important com- munications from the Government of that Dominion, in reference to the record and preservation from obliteration of such traces as still remain of the indigenous characteristics of the native races of America, which subject, the General Committee will recollect, was mentioned in the Report of the Council at the Aberdeen Meeting. Copies of this corre- spondence will be communicated to the Sections interested in the subject. Invitations have been received from Bath and from Sydney for the year 1888; and the invitation from Melbourne, given at Montreal, has been renewed. The following resolutions were referred by the General Committee to the Council for consideration, and action if desirable :— (a) ‘ That the Council be requested to consider the desirability of admitting ladies as Officers of the Association, or as Members of the General or Sectional Committees.’ The Council, after careful consideration of the question, are of opinion that the time has not yet come when it would be for the advantage of the Association to depart from the established custom. (b) ‘That the Council be requested to consider the advisability of rendering the special Reports of the Association more accessible to the scientific public by placing them on sale in separate form.’ (c) ‘That the printed Reports on Special Subjects be offered for sale tothe general public at the time of the Meeting, or as soon afterwards as possible.’ There are several matters of detail, requiring careful consideration, in the subject of these two resolutions, and the Council, owing to exceptional circumstances during the past year, have not been able to come toa decision regarding them. They recommend that the question should be referred to the next Council. d32 lxviil REPORT—1886. (d) ‘ That. the Council be requested to so modify the Rules of the Association as to permit of a Sectional Meeting being held at an earlier hour than eleven, and the Sectional Committee previously, due notice being given to the Section on the previous day.’ The Council have considered this recommendation, and think it un- desirable to alter the general rules, the resolution passed at Southport three years ago meeting the particular case of Saturday. (e) ‘ That a memorial be presented to H.M. Government requesting them to enlarge the existing Agricultural Department of the Privy Council, with the view of concentrating all administrative functions relating to Agriculture in one fully equipped Board and Department of Agriculture.’ The Council, after a full consideration of this difficult and intricate question, are not at present prepared to memorialise the Government on the subject of the enlargement of the Agricultural Department of the Privy Council. (f) ‘That the Council be requested to consider and take steps, if they think it desirable, to memorialise the Government to undertake the more systematic collection and annual publication of Statistics of Wages, and a periodical industrial census.’ The Council, in view of the recent promise of the late President of the Board of Trade in Parliament as to the collection of Statistics of Wages, are of opinion that it is inexpedient at present to memorialise H.M. Government on the subject, but they empowered a committee of their members to communicate, if necessary, with the Department engaged in the collection of Statistics of Wages, with the view of eliciting informa- tion as to the method proposed to be employed, and to make such sug- gestions as appear to be expedient. (g) ‘ That a memorial be presented to H.M. Government in favour of the establishment of a National School of Forestry.’ A Committee was appointed to consider this subject, but has made no report tothe Council. The General Committee will remember that the question of the feasi- bility of instituting a scheme for promoting an International Scientific Congress, described in the Report of the Council presented at Aberdeen, was in effect referred back to the Council to consider whether it would be possible to devise such a scheme. The question has been further con- sidered during the past year, and the Council are of opinion that the difficulties and objections foreseen by several members of the Association have not been met in any of the communications which have been laid before them, and are, in their judgment, so great that they cannot at present recommend any further steps being taken in the matter. In accordance with the regulations the five retiring Members of the Council will be— Mr. J. W. L. Glaisher. Dr. H. C. Sorby. Professor T. McK. Hughes. D. W. H. Perkin. Mr. J. F. La Trobe Bateman. The Council recommend the re-election of the other ordinary Members of Council, with the addition of the gentlemen whose names are distin- guished by an asterisk in the following list :— REPORT OF THE COUNCIL. Abney, Capt. W. de W., F.R.S. Ball, Sir R. S., F.R.S. *Barlow, W. H., Esq., F.R.S. Blanford, W. T., Esq., F.R.S. Bramwell, Sir F. J., F.R.S. Crookes, W., Esq., F.R.S. *Darwin, G. H., F.R.S. Dawkins, Prof. W. Boyd, F.R.S. De La Rue, Dr. Warren, F.R.S. Dewar, Prof. J., F.R.S. Flower, Prof. W. H., F.R.S. Gladstone, Dr. J. H., F.R.S. Godwin-Austen, Lient.-Col. H. H., F.R.S. lxix Hawkshaw, J. Clarke, Esq., F.G.S. Henrici, Prof. O., F.R.S. *Judd, J. W., F.R.S. Martin, J. B., Esq., F.S.S. M‘Leod, Prof. H., F.R.S. Moseley, Prof. H. N., F.R.S. Ommanney, Admiral Sir E., C.B., E.R.S. Pengelly, W., Esq., F.R.S. * Roberts-Austen, Prof.W.C., F.R.S. Temple, Sir R., Bart., G.C.S.I. Thiselton-Dyer, W. T., C.M.G., F.R.S. *Thorpe, T. E., F.R.S. Esq., lxx REPORT—1886. RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE AT THE BiruincHam Meeting 1n SepremMBer 1886. [When Committees are appointed, the Member first named is regarded as the Secretary, except there is a specific nomination. ] Involving Grants of Money. That Professors Balfour Stewart, Schuster, and Stokes, Mr. G. John- stone Stoney, Professor Sir H. E. Roscoe, Captain Abney, and Mr. G. J. Symons be reappointed a Committee for the purpose of considering the best methods of recording the direct intensity of Solar Radiation; that Professor Balfour Stewart be the Secretary, and that the sum of 20]. be placed at their disposal for the purpose. That the Committee consisting of Professors Armstrong, Lodge, and Sir William Thomson, Lord Rayleigh, Professors Fitzgerald, J. J. Thom- son, Schuster, Poynting, Crum Brown, Ramsay, Frankland, Tilden, Hartley, 8. P. Thompson, McLeod, Roberts-Austen, Riicker, Reinold, and Carey Foster, Captain Abney, Drs. Gladstone, Hopkinson, and Fleming, and Messrs. Crookes, Shelford Bidwell, W. N. Shaw, J. Larmor, J.T. Bottomley, and H. B. Dixon, with the addition of the names of Messrs. R. T. Glazebrook, J. Brown, HE. J. Love, and John M. Thomson, be reap- pointed a Committee for the purpose of considering the subject of Elec- trolysis in its Physical and Chemical bearings; that Professor Armstrong be the Chemical Secretary and Professor Lodge the Physical Secretary, and that the sum of’ 50/. be placed at their disposal for the purpose. That Professor Crum Brown, Mr. Milne-Holme, Mr. John Murray, Mr. Buchan, and Lord McLaren be reappointed a Committee for the purpose of co-operating with the Scottish. Meteorological Society in making meteorological observations on Ben Nevis; that Professor Crum Brown be the Secretary, and that the sum of 75l. be placed at their disposal for the purpose. That Professor G. Forbes, Captain Abney, Dr. J. Hopkinson, Professor W. G. Adams, Professor G. C. Foster, Lord Rayleigh, Mr. Preece, Professor Schuster, Professor Dewar, Mr. A. Vernon Har- court, Professor Ayrton, Sir James Douglass, and Mr. H. B. Dixon be reappointed a Committee for the purpose of reporting on Standards of Light; that Professor G. Forbes be the Secretary, and that the sum of 10. be placed at their disposal for the purpose. That Professor G. H. Darwin, Sir W. Thomson, and Major Baird be a Committee for the purpose of preparing instructions for the practical work of Tidal Observation; that Professor Darwin be the Secretary, and that the sum of 154. be placed at their disposal for the purpose. That Professor Balfour Stewart (Secretary), Mr. Knox Laughton, Mr. RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE. xxi G. J. Symons, Mr. R. H. Scott, and Mr. Johnstone Stoney be reappointed a Committee, with power to add to their number, for the purpose of co- operating with Mr. E. J. Lowe in his project of establishing a Meteoro- logical Observatory near Chepstow on a permanent and scientific basis, and that the unexpended sum of 201. be placed at their disposal for the purpose. That Professors Balfour Stewart and Sir W. Thomson, Sir J. H. Lefroy, Professors G. H. Darwin, G. Chrystal, and S. J. Perry, Mr. C. H. Carpmael, Professor Schuster, Mr. G. M. Whipple, Captain Creak, the Astronomer Royal, Mr. Wiiliam Ellis, Professor W. G. Adams, and Mr. W. Lant Carpenter be reappointed a Committee for the purpose of con- sidering the best means of comparing and reducing Magnetic Observa- tions ; that Professor Balfour Stewart be the Secretary, and that the sum of 401. be placed at their disposal for the purpose. That Professor G. Carey Foster, Sir William Thomson, Professor Ayrton, Professor J. Perry, Professor W. G. Adams, Lord Rayleigh, Dr. O. J. Lodge, Dr. John Hopkinson, Dr. A. Muirhead, Mr. W. H. Preece, Mr. Herbert Taylor, Professor Everett, Professor Schuster, Dr. J. A. Fleming, Professor G. F. Fitzgerald, Mr. R. T. Glazebrook, Professor Chrystal, Mr. H. Tomlinson, Professor W. Garnett, Professor J. J. Thomson, Mr. W. N. Shaw, and Mr. J. T. Bottomley be reappointed a Committee for the purpose of making experiments for improving the construction of. practical Standards for use in Electrical Measurements ; that Mr. Glazebrook be the Secretary, and that the sum of 501. be placed at their disposal for the purpose. That Professors McLeod and Ramsay, Mr. J.T. Cundall, and Mr. W. A. Shenstone be a Committee for the further investigation of the Influence of the Silent Discharge of Electricity on oxygen and other gases; that Mr. W. A.Shenstone be the Secretary, and that the sum of 201. be placed at their disposal for the purpose. That Captain Abney, General Festing, and Professors W. N. Hartley and H. E. Armstrong be a Committee for the purpose of investigating the Absorption Spectra of Pure Compounds; that Professor Armstrong be the Secretary, and that the sum of 401. be placed at their disposal for the purpose. That Professors Williamson, Armstrong, Tilden, Reinold, J. Perry, O. J. Lodge, Stirling, Bower, D’Arcy Thompson, and Milnes Marshall, and Messrs. A. V. Harcourt, Dixon, Crookes, and H. J. Love be a Com- mittee for the purpose of considering the desirability of combined action for the purpose of Translation of Foreign Memoirs and for reporting thereon; and that the sum jof 5/. be placed at their disposal for the purpose. That Professors Tilden and W. Ramsay and Dr. W. W. J. Nicol be a Committee for the purpose of investigating the Nature of Solution ; that Dr. W. W. J. Nicol be the Secretary, and that the sum of 20/. be placed at their disposal for the purpose. That Professors Tilden and W. Chandler Roberts-Austen, and Mr. T. Turner be a Committee for the purpose of investigating the Influence of Silicon on the Properties of Steel ; that Mr. T. Turner be the Secretary, and that the sum of 301. be placed at their disposal for the purpose. That Messrs. H. Bauerman, F. W. Rudler, J.J. H. Teall, and H. J. Johnston-Lavis be reappointed a Committee for the purpose of investi- gating the Volcanic Phenomena of Vesuvius and its neighbourhood ; that lxxii REPORT—1886. Dr. H. J. Johnston-Lavis be the Secretary, and that the sum of 207. be placed at their disposal for the purpose. That Mr. R. Etheridge, Mr. T. Gray, and Professor John Milne be reappointed a Cominittee for the purpose of investigating the Volcanic Phenomena of Japan; that Professor J. Milne be the Secretary, and that the sum of 50/. be placed at their disposal for the purpose. That Professor T. McK. Hughes, Dr. H. Hicks, Dr. H. Woodward, and Messrs. E. B. Luxmoore, P. Pennant, and Edwin Morgan be re- appointed a Committee for the purpose of exploring the Cae Gwyn Cave, North Wales; that Dr. H. Hicks be the Secretary, and that the sum of 201. be placed at their disposal for the purpose. That Professors J. Prestwich, W. Boyd Dawkins, T. McK. Hughes, and T. G. Bonney, Dr. H. W. Crosskey, and Messrs. C. E. De Rance, H. G. Fordham, J. HE. Lee, D. Mackintosh, W. Pengelly, J. Plant, and R. H. Tiddeman be reappointed a Committee for the purpose of record- ing the position, height above the sea, lithological characters, size, and origin of the Erratic Blocks of England, Wales, and Ireland, reporting other matters of interest connected with the same, and taking measures for their preservation ; that Dr. Crosskey be the Secretary, and that the sum of 10/. be placed at their disposal for the purpose. That Mr. R. Etheridge, Dr. H. Woodward, and Professor T. R. Jones be reappointed a Committee for the purpose of reporting on the Fossil Phyllopoda of the Paleozoic Rocks; that Professor T. R. Jones be the Secretary, and that the sum of 20/. be placed at their disposal for the purpose. That Professor W. C. Williamson and Mr. Cash be a Committee for the purpose of investigating the Carboniferous Flora of Halifax and its neighbourhood; that Mr. Cash be the Secretary, and that the sum of 251. be placed at their disposal for the purpose. That Professor T. G. Bonney, Mr. J. J. H. Teall, and Professor J. ¥. Blake be a Committee for the purpose of investigating the Microscopic Structure of the older Rocks of Anglesea; that Professor J. F. Blake be the Secretary, and that the sum of 101. be placed at their disposal for the purpose. That Dr. H. Woodward, Mr. H. Keeping, and Mr. J. Starkie Gardner be a Committee for the purpose of exploring the Higher Hocene Beds of the Isle of Wight; that Mr. J. S. Gardner be the Secretary, and that the sum of 201. be placed at their disposal for the purpose. That Professor HE. Hull, Dr. H. W. Crosskey, Captain Douglas Galton, Professor J. Prestwich, and Messrs. James Glaisher, E. B. Marten, G. H. Morton, James Parker, W. Pengelly, James Plant, I. Roberts, Fox Strangways, T. 8. Stooke, G. J. Symons, W. Topley, Tylden-Wright, E. Wethered, W. Whitaker, and C. E. De Rance be reappointed a Com- mittee for the purpose of investigating the Circulation of the Under- ground Waters in the Permeable Formations of England, and the Quality and Quantity of the Waters supplied to various towns and districts from these formations ; that Mr. De Rance be the Secretary, and that the sum of 51. be placed at their disposal for the purpose. That Messrs. R. B. Grantham, C. H. De Rance, J. B. Redman, W. Topley, W. Whitaker, and J. W. Woodall, Major-General Sir A. Clarke, Admiral Sir E. Ommanney, Sir J. N. Douglass, Captain Sir George Nares, Captain J. Parsons, Captain W. J. L. Wharton, Professor J. Prestwich, and Messrs. H. Easton, J. S. Valentine, and L. F. Vernon ee el at wt el RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE. Ixxiii Harcourt be reappointed a Committee for the purpose{of inquiring into the Rate of Erosion of the Sea-coasts of England and Wales, and the Influence of the Artificial Abstraction of Shingle or other material in that Action; that Messrs. De Rance and Topley be the Secretaries, and that the sum of 151. be placed at their disposal for the purpose. That Mr. R. Etheridge, Dr. H. Woodward, and Mr. A. Bell be a Com- mittee for the purpose of reporting upon the ‘Manure’ Gravels of Wexford; that Mr. A. Bell be the Secretary, and that the sum of 10/. be placed at their disposal for the purpose. That Mr. Valentine Ball, Mr. H. G. Fordham, Professor Haddon, Professor Hillhouse, Mr. John Hopkinson, Dr. Macfarlane, Professor Milnes Marshall, Mr. F. T. Mott, Dr. Traquair, and Dr. H. Woodward be a Committee for the purpose of preparing a report upon the Provincial Museums of the United Kingdom; that Mr. Mott be the Secretary, and that the sum of 5/. be placed at their disposal for the purpose. That Professors Schifer, Michael Foster, and Lankester, and Dr. W. D. Halliburton be a Committee for the purpose of investigating the Physiology of the Lymphatic System; that Professor Schafer be the Secretary, and that the sum of 25/. be placed at their disposal for the purpose. That Professor Ray Lankester, Mr. P. L. Sclater, Professor M. Foster, Mr. A. Sedgwick, Professor A. M. Marshall, Professor A. C. Haddon, Professor Moseley, and Mr. Percy Sladen be reappointed a Committee for the purpose of arranging for the occupation of a table at the Zoological Station at Naples; that Mr. Percy Sladen be the Secretary, and that the sum of 100/. be placed at their disposal for the purpose. That Professor Lankester, Mr. P. L. Sclater, Professor M. Foster, Mr. A. Sedgwick, Professor A. M. Marshall, Professor A.C. Haddon, Professor Moseley, and Mr. Percy Sladen be a Committee for the purpose of making arrangements for assisting the Marine Biological Association Laboratory at Plymouth; that Mr. Percy Sladen be the Secretary, and that the sum of 50. be placed at their disposal for the purpose. That Professors McKendrick, Struthers, Young, McIntosh, A. Nichol- son, and Cossar Ewart and Mr. John Murray be reappointed a Committee for the purpose of aiding in the maintenance of the establishment of a Marine Biological Station at Granton, Scotland; that Mr. John Murray be the Secretary, and that the sum of 751. be placed at their disposal for the purpose. That Mr. Stainton, Sir John Lubbock, and Mr. McLachlan be re- appointed a Committee for the purpose of continuing a Record of Zoo- logical Literature ; that Mr. Stainton be the Secretary, and that the sum of 100. be placed at their disposal for the purpose. That Mr. Thiselton Dyer, Mr. Carruthers, Mr. Ball, Professor Oliver, and Mr. Forbes be a Committee for the purpose of continuing the prepa- ration of a report on our present knowledge of the Flora of China; that Mr. Thiselton-Dyer be the Secretary, and that the sum of 75/. be placed at their disposal for the purpose. That Mr. Sclater, Mr. Seebohm, Mr. Carruthers, and Mr. R. Trimen be a Committee for the purpose of investigating the Fauna and Flora of the Cameroon Mountains ; that Mr. Sclater be the Secretary, and that the sum of 75/1. be placed at their disposal for the purpose. That Mr. John Cordeaux, Professor A. Newton, Mr. J. A. Harvie- Brown, Mr. W. E. Clarke, Mr. R. M. Barrington, and Mr. A. G. More lxxiv REPORT—1886. be reappointed a Committee for the purpose of obtaining (with the consent of the Master and Elder Brethren of the Trinity House and the Commis- sioners of Northern and Irish Lights) observations on the Migration of Birds at Lighthonses and Light-vessels, and of reporting on the same; that Mr. John Cordeaux be the Secretary, and that the sum of 301. be placed at their disposal for the purpose. That Canon A. M. Norman, Mr. H. B. Brady, Mr. W. Carruthers, Professor Herdman, Professor McIntosh, Mr. J. Murray, Professor A. Newton, Mr. P. L. Sclater, and Professor A. C. Haddon be a Committee for the purpose of considering the question of accurately defining the term ‘ British’ as applied to the Marine Fauna and Flora of our Islands, and bringing forward a definite proposal on the subject at a future meet- ing. The Committee to be called the ‘ British Marine Area Committee.’ That Professor A. C. Haddon be the Secretary, and that the sum of 51. be placed at their disposal for the purpose. That General J.T. Walker, General Sir J. H. Lefroy, Professor Sir William Thomson, Mr. Francis Galton, Mr. Alexander Buchan, Mr. J. Y. Buchanan, Mr. John Murray, Mr. H. W. Bates, and Mr. E. G. Raven- stein be a Committee for the purpose of taking into consideration the combination of the Ordnance and Admiralty Surveys, and the production of a Bathy-hypsographical Map of the British Isles; that Mr. E. G. Ravenstein be the Secretary, and that the sum of 251. be placed at their disposal for the purpose. That General J. T. Walker, General Sir J. H. Lefroy, Professor Sir William Thomson, Mr. Alexander Buchan, Mr. J. Y. Buchanan, Mr. John Murray, Dr. J. Rae, Mr. H. W. Bates, Captain W. J. Dawson, Dr, A. Selwyn, and Professor ©. Carpmael be reappointed a Committee for the purpose of reporting upon the Depth of permanently Frozen Soil in the Polar Regions, its geographical limits, and relation to the present poles of greatest cold; that Sir Henry Lefroy be the Reporter and Mr. H. W. Bates the Secretary, and that the sum of 5/. be placed at their disposal for the purpose. That Professor Sidgwick, Professor Foxwell, the Rey. W. Cunningham, Professor Munro, and Mr. A. H. D. Acland be a Committee for the purpose ef further inquiring into the Regulation of Wages under the Sliding Scales and under the Lists in the Cotton Industry ; that Professor Munro be the Secretary, and that the sum of 10/. be placed at their disposal for the purpose. That Dr. Garson, Mr. Pengelly, Mr. F. W. Rudler, and Mr. G. W. Bloxam be reappointed a Committee for the purpose of investigating the Prehistoric Race in the Greek Islands; that Mr. Bloxam be the Secretary, and that the sum of 20/. be placed at their disposal for the purpose. That Mr. Pengelly, Dr. John Evans, Sir John Lubbock, Professor Alexander Macalister, Mr. W. Cunnington, and Dr. Garson be a Com- mittee for the purpose of exploring Ancient Barrows in Wiltshire; that Dr. Garson be the Secretary, and that the sum of 20/. be placed at their disposal for the purpose. That Dr. E. B. Tylor, Dr. G. M. Dawson, General Sir J. H. Lefroy, Dr. Daniel Wilson, Mr. R. G. Haliburton, and Mr. George W. Bloxam be reappointed a Committee for the purpose of investigating and publishing reports on the physical characters, languages, and industrial and social condition of the North-Western Tribes of the Dominion of Canada; that RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE. lxxv Mr. Bloxam be the Secretary, and that the sum of 501. be placed at their disposal for the purpose. That Mr. F. Galton, General Pitt-Rivers, Professor Flower, Professor A. Macalister, Mr. F. W. Rudler, Mr. R. Stuart Poole, and Mr. Bloxam be a Committee for the purpose of procuring, with the help of Mr. Flinders Petrie, Racial Photographs from the Ancient Egyptian Pictures and Sculptures; that Mr. Bloxam be the Secretary, and that the sum of 201. be placed at their disposal for the purpose. That General Pitt-Rivers, Dr. Beddoe, Professor Flower, Mr. Francis Galton, Dr. E. B. Tylor, and Dr. Garson be a Committee for the purpose of editing a new edition of ‘Anthropological Notes and Queries,’ with authority to distribute gratuitously the unsold copies of the present edition ; that Dr. Garson be the Secretary, and that the sum of 101. be placed at their disposal for the purpose. Not involving Grants of Money. That Professor Cayley, Sir William Thomson, Mr. James Glaisher, and Mr. J. W. L. Glaisher (Secretary) be reappointed a Committee for the purpose of calculating certain tables in the Theory of Numbers connected with the divisors of a number. That Professor G. H. Darwin and Professor J. C. Adams be reap- pointed a Committee for the Harmonic Analysis of Tidal Observations ; and that Professor Darwin be the Secretary. That Professors Everett and Sir William Thomson, Mr. G. J. Symons, Sir A. C. Ramsay, Dr. A. Geikie, Mr. J. Glaisher, Mr. Pengelly, Professor Edward Hull, Professor Prestwich, Dr. C. Le Neve Foster, Professor A. S. Herschel, Professor G. A. Lebour, Mr. A. B. Wynne, Mr. Galloway, Mr. Joseph Dickinson, Mr. G. F. Deacon, Mr. EK. Wethered, and Mr, A. Strahan be reappointed a Committee for the purpose of investigating the Rate of Increase of Underground Temperature down- wards in various Localities of Dry Land and under Water ; and that Pro- fessor Everett be the Secretary. That Professor Sylvester, Professor Cayley, and Professor Salmon be reappointed a Committee for the purpose of calculating Tables of the Fundamental Invariants of Algebraic Forms; and that Professor Cayley _ be the Secretary. Fs a That Professors A. Johnson, MacGregor, J. B. Cherriman, and H. T. Bovey and Mr. C. Carpmael be reappointed a Committee for the purpose of promoting Tidal Observations in Canada; and that Professor Johnson be the Secretary. That Mr. John Murray, Professor Schuster, Sir William Thomson, the Abbé Renard, Mr. A. Buchan, the Hon. R. Abercromby, and. Dr. M. Grabham be reappointed a Committee for the purpose of investigating the practicability of collecting and identifying Meteoric Dust, and of considering the question of undertaking regular observations in various localities ; and that Mr. John Murray be the Secretary. _ That Professor Sir H. E. Roscoe, Mr. Lockyer, Professors Dewar, Liveing, Schuster, W. N. Hartley, and Wolcott Gibbs, Captain Abney, and Dr. Marshall Watts be a Committee for the purpose of preparing a new series of Wave-length Tables of the Spectra of the Hlements ; and that Dr. Marshall Watts be the Secretary. That Professors W. A. Tilden and H. E. Armstrong be a Committee Ixxvi REPORT— 1886. for the purpose of investigating Isomeric Naphthalene Derivatives; and that Professor H. HE. Armstrong be the Secretary. That Professors Dewar and A. W. Williamson, Dr. Marshall Watts, Captain oe Dr. Johnstone Stoney, Professors W. N. Hartley, McLeod, Carey Foster, A. K. Huntington, Emerson Reynolds, Reinold, and live: ing, Lord Rayleigh, Professor Schuster, and ‘Professor W. C. ‘Roberts- Austen be a Committee for the purpose of reporting upon the present state of our knowledge of Spectrum Analysis; and that Professor W. C. Roberts-Austen be the Secretary. That Professors Ramsay, Tilden, Marshall, and W. L. Goodwin be a Committee for the purpose of investigating certain Physical Constants of Solution, especially the expansion of saline solutions ; and that Pro- fessor W. L. Goodwin be the Secretary. That Professors Tilden, McLeod, Pickering, and Ramsay and Drs. Young, A. R. Leeds, and Nicol be a Committee for the purpose of re- porting on the Bibliography of Solution; and that Dr. Nicol be the Secretary. That Dr. J. Evans, Professor W. J. Sollas, Dr. G. J. Hinde, and Messrs. W. Carruthers, R. B. Newton, J. J. H. Teall, F. W. Rudler, W. Topley, W. Whitaker, and E. Wethered be reappointed a Committee for the pur- pose of carrying on the Geological Record; and that Mr. W. Topley be the Secretary. That Dr. W. T. Blanford, Professor J. W. Judd, Mr. W. Carruthers, Dr. H. Woodward, and Mr. J. S. Gardner be reappointed a Committee for the purpose of reporting on the Fossil Plants of the Tertiary and Secondary Beds of the United Kingdom; and that Mr. J. S. Gardner be the Secretary. That Professor Hillhouse, Mr. E. W. Badger, and Mr. A. W. Wills be a Committee for the purpose of collecting information as to the Dis- appearance of Native Plants from their local habitats ; and that Professor Hillhouse be the Secretary. That Professor Milnes Marshall, Dr. Sclater, Canon Tristram, Dr. Muirhead, Mr. W. R. Hughes, Mr. H. de Hamel, and Professor Bridge be a Committee for the purpose of preparing a report on the Herds of Wild Cattle in Chartley Park and other parks in Great Britain ; and that Mr. W. R. Hughes be the Secretary. That Professor M. Foster, Professor Bayley Balfour, Mr. Thiselton- Dyer, Dr. Trimen, Professor Bower, Professor Marshall Ward, Mr. Car- ruthers, and Professor Hartog be a Committee for the purpose of taking steps for the establishment of a Botanical Station at Peradeniya, Ceylon ; and that Professor Bower be the Secretary. That Professor McKendrick, Professor Cleland, and Dr. McGregor- Robertson be a Committee for the purpose of investigating the Mechanism of the Secretion of Urine; and that Dr. McGregor-Robertson be the Secretary. That Sir Joseph Hooker, Captain Sir George Nares, Admiral Sir Leopold McClintock, Mr. Clements R. Markham, General Sir Henry Lefroy, General J. T. Walker, Professor Flower, Professor Huxley, Sir William Thomson, General Strachey, Sir John Lubbock, Mr. John Murray, and Admiral Sir Erasmus Ommanney be reappointed a Com- mittee for the purpose of drawing attention to the desirability of further research in the Antarctic Regions; and that Admiral Sir Erasmus Om- manney be the Secretary. RECOMMENDATIONS ADOPTED BY THE GENERAL COMMITTEE. Ixxvii That the Rev. Canon Carver, the Rev. H. B. George, Captain Douglas Galton, Professor Bonney, Mr. A. G. Vernon Harcourt, Professor T. McKenny Hughes, the Rev. H. W. Watson, the Rev. H. F. M. McCarthy, the Rev. A. R. Vardy, Professor Alfred Newton, the Rev. Canon Tris- tram, Professor Moseley, and Mr. HE. G. Ravenstein be a Committee for _ the purpose of co-operating with the Royal Geographical Society in endeavouring to bring before the authorities of the Universities of Oxford and Cambridge the advisability of promoting the study of Geography by establishing special chairs for the purpose; and that Mr. H. G. Raven- stein be the Secretary. That Mr. J. B. Martin, Mr. F. Y. Edgeworth, Mr. S. Bourne, Pro- fessor H. S. Foxwell, Professor Marshall, Professor Nicholson, Mr. R. H. Inglis Palgrave, and Professor Sidgwick be a Committee for the purpose of investigating the best methods of ascertaining and measuring Variations in the Value of the Monetary Standard; and that Mr. F. Y. Edgeworth be the Secretary. That Dr. J. H. Gladstone, Professor Armstrong, Mr. William Shaen, Mr. Stephen Bourne, Miss Lydia Becker, Sir John Lubbock, Dr. H. W. Crosskey, Sir Richard Temple, Sir Henry E. Roscoe, Mr. James Heywood, and Professor N. Story Maskelyne be reappointed a Committee for the purpose of continuing the inquiries relating to the teaching of Science in Elementary Schools; and that Dr. J. H. Gladstone be the Secretary. That Mr. W. H. Barlow, Sir F. J. Bramwell, Professor J. Thomson, Captain D. Galton, Mr. B. Baker, Professor W. C. Unwin, Professor A. B. W. Kennedy, Mr. C. Barlow, Mr. A. T. Atchison, and Professor H. 8. Hele Shaw be reappointed a Committee for the purpose of obtain- ing information with reference to the Endurance of Metals under repeated and varying stresses, and the proper working stresses on railway bridges and other structures subject to varying loads; and that Mr. A. T. Atchison be the Secretary. That Sir John Lubbock, Dr. John Evans, Professor Boyd Dawkins, Dr. R. Munro, Mr. Pengelly, Dr. Hicks, Mr. J. W. Davis, and Dr. Muir- head be a Committee for the purpose of ascertaining and recording the localities in the British Islands in which Evidences of the Existence of Prehistoric Inhabitants of the Country are found; and that Mr. J. W. Davis be the Secretary. That Professor J. J. Thomson be requested to continue his Report on Electrical Theories. That Mr, Glazebrook be requested to continue his Report on Optics. That Mr. P. T. Main be requested to continue his Report on our experimental knowledge of the Properties of Matter with respect to volume, pressure, temperature, and specific heat. That Mr. Mollison be requested to report on the present state of our knowledge of the Mathematical Theory of Thermal Conduction. That Professor Armstrong be requested to prepare a Report on the Relation of Physical Properties to Chemical Constitution. Communications ordered to be printed in extenso in the Annual Report of.the Association. Dr. A. Konig’s paper ‘On the Modern Development of Thomas Young’s Theory of Colour- Vision.’ Ixxvili REPORT—-1 886. Mr. Harley’s paper containing the explicit form of the Complete Cubic Differential Resoivent. Professor Tilden’s report ‘On the Nature of Solution.’ Mr. J. W. Davis’s paper ‘ On the Raygill Fissure.’ Mr. J. Player’s paper ‘On a Rapid Method of Estimating Silica in Rocks.’ Messrs. W. Shelford and A. H. Shield’s paper ‘ On some Points for the Consideration of English Engineers with reference to the Design of Girder Bridges.’ Professor Hele Shaw and Mr. Edward Shaw’s paper ‘ On the Sphere and Roller Mechanism for Transmitting Power’ (with the necessary diagrams). Mr. J. Wilson Swan’s paper ‘On Improvements in Electric Safety Lamps.’ ie W.S. Till’s paper ‘On the Birmingham District Drainage.’ Resolutions referred to the Council for Consideration, and Action if desirable. That the Council be requested to consider the question of rendering the Reports and other papers communicated to the Association more readily accessible to the members and others by issuing a limited number of them in separate form, or in associated parts, in advance of the annual volume. That the Council be requested to consider whether a memorial should be presented to Her Majesty’s Government, urging them to undertake and supervise Agricultural Experiments, and to procure further and more complete Agricultural Statistics. That the Council be requested to consider the advisability of calling the attention of the proprietor of Stonehenge to the danger in which several of the stones are at the present time from the burrowing of rabbits, and also to the desirability of removing the wooden props which support the horizontal stone of one of the trilithons; and in view of the great value of Stonehenge as an ancient national monument to express the hope of the Association that some steps will be taken to remedy these sources of danger to the stones. SYNOPSIS OF GRANTS OF MONEY. lxxix * Synopsis of Grants of Money appropriated to Scientific Pur- poses by the General Committee at the Birmingham Meeting im September 1886. The Names of the Members entitled to call on the General Treasurer for the respective Grants are prefixed. Mathematics and Physics. ao RSs Oe *Stewart, Professor Balfour.—Solar Radiation .................. 20 0 O =Armstrong, Professor.—EHlectrolysis ...............c.scceesessecee 50 0 0 *Brown, Professor Crum.—Ben Nevis Observatory ............ > OO *¥Forbes, Professor G.—Standards of Light.....................04. 1 hail 3 aah *Darwin, Professor G. H.—Tidal Observations: Instructions 15 0 0O *Stewart, Professor Balfour.—Chepstow Meteorological Ob- TL a Mh Sl ae ee an eal OE LE pr EA Peers 3 ae 20 Oy .G *Stewart, Professor Balfour. Doveipaeiie Observations ......... 40 0 0 *Foster, Professor G. Carey. eanistieieal Standards ............ 50 0 Chemistry. *M‘Leod, Professor.—Silent Discharge of Electricity ......... 20 0 0 Abney, Captain.—Absorption Spectra .............:ccceeeeee noes 40 0 0 Williamson, Professor A. W.—Translation of Foreign reas polo Sue aS aac foam nn ge fonwennd ~ a poe eee Seeee aria 6 Tilden, Professor. —Nature of Solution AO a Neda 20 0 O Tilden, Professor.—Influence of Silicon on Steel ............... 30 0 Geology. _*Bauerman, Mr. H.—Volcanic Phenomena of Vesuvius ...... 20.0 0 *Ktheridge, Mr. R.—Volcanic Phenomena of Japan ............ 50 0 0 *Hughes, Professor T. McK.—Exploration of Cae Gwyn Cave 20 0 0 *Prestwich, Professor J.—Erratic Blocks ....................008. 10): *Etheridge, Mr. R.—Fossil Phyllopoda, .................0005 se0ees 20 0 0 Williamson, Professor W. C.—Carboniferous Flora of Halifax 25 0 0 Bonney, Professor.—Microscopic Structure of the Rocks of ESIC EA Pte iterate ac honed nnn Scand doe rye turdeodeiacenk 10} / 0°) 0 Woodward, Dr. H.— Eocene Beds of the Isle of Wight ...... 20 m0. 0 *Hull, Professor E.—Circulation of Underground Waters ... 5 O O *Grantham, Mr. R. B.—Erosion of Sea Coasts .................. 15) OO Etheridge, Mr. R.—‘ Manure ’ Gravels of Wexford ............ 10 0 0 Ball, Mr. Valentine.—Provincial Museum Reports ............ 5 0 0 Carried ar Ward. insta. sors csc vatngh casei tineaseo eas £605 0 0 * Reappointed. lxxx REPORT—1886. . ZB... 85 he POU LOR IAED yaacosieck 2s 0% on age eae reversed bencdiieie Ove sab sete 605 0 0 Biology. Schafer, Professor—Lymphatic System .................0000008 25 0 0 *Lankester, Professor Ray.—Naples Biological Station......... 100 0 O Lankester, Professor Ray.—Plymouth Biological Station ... 50 0 O *McKendrick, Professor.—Granton Biological Station ...... ioe 0 *Stainton, Mr. H. T.—Zoological Record .........:.....-2.e8e00s 100 “6. 38 Thiselton-Dyer, Mr.—Flora of China ............ssseeeeeereee 75 0 0 Sclater, Mr.—Flora and Fauna of the Cameroons .............. 7o 0 0 *Cordeaux, Mr. J.—Migration of Birds ....................0ceeees 30 0 0 Norman, Canon A. M.—British Marine Area .................. 5 0 0 Geography. *Walker, General J. T.—Bathy-Hypsographical Map ......... 250» Or uO *Walker, General J. T.—Depth of Permanently Frozen Soil... 5 0 0 Economic Science and Statistics. *Sidgwick, Professor.—Regulation of Wages..............0...04 10. Ore Anthropology. *Garson, Dr.—Prehistoric Races of Greek Islands ............ 20.°0 70 Pengelly, Mr.—British Barrows...............cc0.sscseseeeseeeeeees 20 0 0 *Tylor, Dr. E. B.—North-Western Tribes of Canada............ 50 0 O *Galton, Mr. F.—Racial Photographs: Egyptian ............... 20 0 0 Pitt-Rivers, General.—Anthropological Notes and Queries... 10 0 0O £1300 0 0 * Reappointed. The Annual Meeting in 1887. The Meeting at Manchester will commence on Wednesday, August 31. Place of Meeting in 1888. The Annual Meeting of the Association will be held at Bath. GENERAL STATEMENT. lxxxi General Statement of Sums which have been paid on account of Grants for Scientific Purposes. Hi) high! d. 1834 Tide Discussions ...... Sscddons 20 0 0 1835. Tide Discussions ...........+0++ 62 0 0 British Fossil Ichthyology ... 105 0 0 ) £167 0 O 1836. Tide Discussions ........... xotios o Ge Ope 0: British Fossil Ichthyology ... 105 0 0 Thermometric Observations, iO. obskehoe hor bod Speocecueeeee cee 50 0 0 Experiments on long-con- APRICOT CA fee nowasdessncoess Withee O Rain-Gauges ...........00066 emo ss O Refraction Experiments ...... ED Oi010 Lunar Nutation..............005 60 0 O MRERMOMELETS........000.sea0e% 1bwaGt © £435 0 O 1837. Tide Discussions ............00. 284 1 0 Chemical Constants ............ 2413 6 Mnnar Natation..........c00s00.. 70 0 O Observations on Waves ...... 100 12 0 SNES At DIISLOL 0, 0 IMUGMIn MRIVers**i:25itesccnctetece a 0" .0 e€ Ixxxii COR Marine Zoology ...... spas cosous 1512 8 Skeleton Maps ......--.ssseseeee 20 0 0 Mountain Barometers ......... 618 6 Stars (Histoire Céleste) ...... 185 0 0 Stars (acaille)...........cecerss 798 <6) 10 Stars (Nomenclature of)...... 1719 6 Stars (Catalogue of) ............ 40171010 Water On Irony. feseeecsesee cee 50 0 0 Meteorological Observations at INVerneSS .........3+.c0000 20 0 0 Meteorological Observations (reduction Of) ......6+ sseee 25 0 0 Hoss!) Reptiles. .vonescwceccecns 50 0 0 Foreign Memoirs .........:000 62 0 6 Railway Sections ............+++ Bis! elle (0) Forms of Vessels ........0.002+. 193 12 0 Meteorological Observations AGP RyIMOUDMN sr ecssneneeseas ee 55 0 0 Maenetical Observations ...... 6118 8 Fishes of the Old Red Sand- BUOMC His ta cescebsducastatensnnvess 100 0 Tides at Leith .2......0....0000 50 0 Anemometer at Edinburgh... 69 11 Tabulating Observations ...... 916 RACESIOMMEHeossdat-ucodseceeesse 5 0 Radiate Animals ..............- 2 0 £1235 10 1 1842. Dynamometric Instruments... 113 11 2 Anoplura Britanniz ............ 5212 0 Tides at Bristol ............0.0 59 8 O Gasesion Light) 2c: sis.cc.ccsctese 30 14 7 ChrONOMELETS:.\.-..s0c0ccenascuns 2617 6 Marine Zoology..........0....0s. Sti yg) British Fossil Mammalia...... 100 0 0 Statistics of Education......... 20 0 0 Marine Steam-vessels’ En- DIMES Mescaccsdetatececects eases 28 0 0 Stars (Histoire Céleste) ...... 59 0 0 Stars (Brit. Assoc. Cat. of)... 110 0 0 Railway Sections ............... 161 10 O British Belemnites .. ......... AVE Os 0) Fossil Reptiles (publication OLE DOTL) tattacnes coneseeteece ZO 0 0 Forms of Vessels ............0:. 180 0 0 Galvanic Experiments on ROCKS eccemeieseasoe ceases seeeee 5 8 6 Meteorological Experiments at Plymomth src sr ccssceee 68 0 0 Constant Indicator and Dyna- mometric Instruments ...... 90) *ORz0 Horce: Of Wand). sascccscss oreiees 10) 0; 0 Light on Growth of Seeds ... 8 O O Vital Statistics ............0.08e oe ON OP XG Vegetative Power of Seeds... 8 1 11 Questions on Human Race... 7 9 O £1449 17 8 See ee 1843. Revision of the Nomenclature TOIMS UALS es cnn ccirsescicate ce pa Pe 0 pe OoOowooco REPORT—1886. ch Ce Reduction of Stars, British Association Catalogue ...... 25 0 0 Anomalous Tides, Frith of HOTGOM ssstacse ‘Op40 GENERAL STATEMENT. Le Bs Investigations into the Mol- lusca of California ......... 10 0 Experiments on Flax ......... 5 0 Natural History of Mada- PAH een acensneecccceosessan 20 0 Researches on British Anne- MUM Waals sss tgeesescs ce cvonse 25 0 — Report on Natural Products imported into Liverpool... 10 0 Artificial Propagation of Sal- PHRSteem eer eencrasc-ssss--ceese 10 0 Temperature of Mines......... es Thermometers for Subterra- nean Observations...........- pend WEG HORUS. 5... .c:2-2-0sc+necece see pO £507 15 1858. Maintaining the Establish- ment at Kew Observatory 500 0 Earthquake Wave Experi- MEUM as ais sss cwsss steeswertoace 25 0 0 Dredging on the West Coast DINSCORANG 5. 50cs.s0cedseveeses 10 0 O _ Dredging near Dublin........, Be1Q2i0 | Vitality of Seeds ............... e540) Dredging near Belfast......... 18 13. 2 _ Report on the British Anne- Ung Eas Poeeetwaeteecceessecen 25 0 0 _ Experiments on the produc- tion of Heat by Motion in BEACON 232 9ccsccsc2-cccbecessedees 20.0 0 Report on the Natural Pro- ducts imported into Scot- [boc oe soda teesinerere 10 0 0 £618 18 2 1859. Maintaining the Establish- ment at Kew Observatory 500 0 Dredging near Dublin......... 15 0 Osteology of Birds ............ 50 0 Prishiamicata: ..s.s0.sesces.0s. 5 0 Manure Experiments ......... 20 0 British Meduside ............... S00 Dredging Committee ......... 59 -Oet' Steam-vessels’ Performance... 5 0 0 Marine Fauna of South and West of Ireland............... 10 0 0 Photographic Chemistry ...... 10 0 0 Lanarkshire Fossils ............ 207 Obed! Balloon Ascents............-..... 3911-90 £684 11 1 1860. Maintaining the Establish- ment at Kew Observatory 500 0 0 redging near Belfast......... 16 6 0 redging in Dublin Bay...... LStRO HO quiry into the Performance of Steam-vessels ....... wseve 124 0,0 Xplorations in the Yellow Sandstone of Dura Don 20 .0 0 RPIOPR CO C CoC oc co & ooooco £ s.-d. Chemico-mechanical Analysis of Rocks and Minerals...... 25 0 0 | Researches on the Growth of |) #y Plan tisgee cee ee sceztuvecnsdenats = 10 0 0 Researches on the Solubility Ole Dakitveascnsatecersecsnssoces 30 0 0 Researches on theConstituents of Manures | lcacsesen:eaceess 25 0 O Balance of Captive Balloon PCCOUDRES: «cnacet ness aentees eae is 6 £766 19 6 1861. Maintaining the Establish- ment of Kew Observatory... 500 0 O Earthquake Experiments...... 25 0 0 Dredging North and East Coasts of Scotland ......... 23 0 0 Dredging Committee :— 1860...... £50 0 0 72 0 0 1861......£22 0 0 on Excavations at Dura Den...... 20 0 0 Solubility of Salts ............ 20 0 0 Steam-vessel Performance ... 150 0 0 Fossils of Lesmahago ......... LE TOTO Explorations at Uriconium... 20 0 0 Chemical Alloys ............... 20 0 0 Classified Index to the Trans- BCHONS 2 seowsewenpeseceneseree res 100 0 0 Dredging in the Mersey and WEG eens et eroecaneesomere ee aeop hon Ol 0, Dip" Cinele) ccccssecustaneedsesean 30 0 O Photoheliographic Observa- PADDS! Yo cecccetcbiceearteosee nets 50, 00 Prison Diet ssssccasensscssecenwe st 20 0 0 Gauging of Waiter..........--s9= 10 0 0 Alpine ASGents) sc... secsocers 6 5 10 Constituents of Manutes ...... 25 0 0 #1111 5 10 1862. Maintaining the Hstablish- ment of Kew Observatory 500 0 0 Patent Laws ....0c.0.scssencsos 2 6; 0 Mollusca of N.-W. of America 10 0 0 Natural History by Mercantile Marinieny Jishekacnaeese <2. ease bigGig O Tidal Observations pecan 25 0 0 Photoheliometer at Kew ...... 40 0 0 Photographic Pictures of the SUNG eS eednaeeeeakareces alone as 150) 0.0 Rocks of Donegal............... 25 0 0 Dredging Durham and North- umberlang ,....ncsessechevatsoe~as 25 0 O Connexion of Storms ......... 20 0 0 Dredging North-east Coast of Scotland!) -.5:.< 17 3 10 Dredging Committee superin- RiGNIGL ONCE, eWekmash osiecicgn osvsbe 10 0 0 Steamship Performance ...... 100 0 0 Balloon Committee ............ 200 0 0 Carbon under pressure ......... 10; 5.00 Voleanic Temperature ......... 100 0 0 Bromide of Ammonium ...... 8, 10) 0 Electrical Standards............ 100 0 0 Electrical Construction and DIStEUDUTION’...c.ssn0s5eeen0en 40 0 0 Luminous Meteors ............ LZ, «Ob 0 Kew Additional Buildings for Photoheliograph ............ 100 0 O Thermo-Electricity ............ 15 0 0 Analysis of Rocks ..!......... 8 0 0 Ey OMOTGasar.ciatseossttocscsteeesne 10 0 0 £1608 3 10 1864. Maintaining the Hstablish- ment of Kew Observatory.. 600 0 0 Coal Fossils ..... atarsawecerdiee 20 0-0 Vertical Atmospheric Move- BRIGG) Pence teecene se tate tedtenncnce 20 0 0 Dredging Shetland ............ EOE 0) Dredging Northumberland... 25 0 0 Balloon Committee ............ 200 0 0 Carbon under pressure ...... TOM OFAO Standards of Electric Re- SISUANCE), sacetueeesceeeereserceee 100 0 0 Analysis of Rocks ............ TOMO 0 NV GnOTUa: ..ccvccsesovencenee test 10 0 O Pas hams \Gidtie. weteese ree ese EL 0) 40) Nitrite of Amyle ............... 10 0 0 Nomenclature Committee ... 5 0 0 AIN=GAUSES)..-veeseososcccees vues LOLS 8 Cast-Iron Investigation ...... 20 0 90 REPORT— 1886. £2 80d. Tidal Observations in the TIM DCL Mivadesasss ence thee 50 0 O Spectral RAys....sc..scccenseceas 45 0 O Luminous Meteors .........+.. 20 0 0 £1289 15 8 1865. Maintaining the EHstablish- ment of Kew Observatory.. 600 0 0 Balloon Committee ...........+ 100 0 O EUV OM OLE Siac sepenseviaccsc's an eeeee ae 13 S00. | Ralne Ga eGS: "ls. cos csneacdeeeesad 30 0 0 Tidal Observations in the IMB OL ve aaa So< noses cbvap bers 6 8 0 Hexylic Compounds ............ 20 0 0 Amyl Compounds ............... 20 0 0 Trish: Wlorajccescsssscacsscccaseeene 25 0 0 American Mollusca ............ 3. 190 OrganicyACiGsy i seocen--ssuer out 20 0 0 Lingula Flags Excavation ... 10 0 0 | SHPUTyPLOLUS! scieteennasosssecemeeens 50 0 O Electrical Standards............ 100 0 O | Malta Caves Researches ...... 530 0 O Oyster Breeding. ........c.«.-ess 25 0 0 Gibraltar Caves Researches... 150 0 O Kent’s Hole Excavations...... 100 0 O Moon’s Surface Observations 35 0 O Marine Hatinaiy()2.:cwensccceceke 25 0 0 Dredging Aberdeenshire ...... 25 0 0 Dredging Channel Islands ... 50 0 0 Zoological Nomenclature...... 5 0 0 Resistance of Floating Bodies TSW LOLetven. cpaaiicdas Seemed 100-010 Bath Waters Analysis ......... 8 10 10 Luminous Meteors ............ 40 0 O ‘£1 5 591 OF AG 1866. Maintaining the Hstablish- ment of Kew Observatory.. 600 0 0 Lunar Committee.............. 64 13 4 Balloon Committee ............ 50 O O Metrical Committee............ 50 0 O rihishwnaim tallies. .cs.ssccseere 50 0 O Kilkenny Coal Fields ......... 16 0 0 | Alum Bay Fossil Leaf-Bed... 15 0 0 | Luminous Meteors ............ 50 0 O | Lingula Flags Excavation ... 20 0 0 | Chemical Constitution of OBStMIONT) Gc deeted wens teees 50.. 08 0 | Amyl Compounds ............... 25 0 0 Electrical Standards............ 100 0 O Malta Caves Exploration ...... 30 0 0 Kent’s Hole Exploration .,.... 200 0 0 | Marine Fauna, &c., Devon and Corniwallltpeacres...cderede 25 O20 Dredging Aberdeenshire Coast 25 0 0 Dredging Hebrides Coast 50 0 O Dredging the Mersey ......... 5 0 0 Resistance of Floating Bodies in Walbetnctedese coe veecencomeds 50 0 0 | Polyeyanides of Organic Radi- CHIR Res shecardactet) Soetiae ee 29° ORO 1867. Maintaining the Establish- ment of Kew Observatory.. 600 Meteorological Instruments, IPAIOSUING...cacaccsscdcoecsccesess 50 Lunar Committee ............... 120 Metrical Committee ............ 30 Kent’s Hole Explorations 100 Palestine Explorations......... 50 Insect Fauna, Palestine ...... 30 Prmigish, Ramiall....iccscsccccsces 50 Kilkenny Coal Fields ......... 25 Alum Bay Fossil Leaf-Bed ... 25 Luminous Meteors ............ 50 Bournemouth, &c., Leaf-Beds 30 Dredging Shetland ............ 75 Steamship Reports Condensa- TION. .a<.5-s Bees sida as coatigacciceaws 100 Electrical Standards............ 100 Ethyl and Methyl series ...... 25 Fossil Crustacea ............... 25 Sound under Water ............ 24 North Greenland Fauna ...... 75 Do. Plant Beds 100 Tron and Steel Manufacture... 25 PEBEGONG TAWS: .eecveecedaancevsese 30 £1739 1868. Maintaining the Establish- ment of Kew Observatory.. 600 iunar Committee ............... 120 Metrical Committee............ 50 _ Zoological Record............... 100 Kent’s Hole Explorations 150 Steamship Performances ...... 100 pridish Rainfall .........css..0. 50 Luminous Meteors............... 50 Organic Acids .....5........0:0 60 Fossil Crustacea..............0c0 25 Methyl Series......... BECERCCE EE 25 Mercury and Bile ............... 25 Organic Remains in Lime- BEONe ROCKS ...2.....000 Aen, OP) Scottish Earthquakes ....... 20 Fauna, Devon and Cornwall.. 30 British Fossil Corals ......... 50 Bagshot Leaf-Beds ............ 50 Greenland Explorations ...... 100 MPBSSUUH OTA... ..0scsecacevesasee 25 Tidal Observations ............ 100 Underground Temperature... 50 Spectroscopic Investigations of Animal Substances ...... 5 eo oooooococoocoeoco (=) So cooocococoeco cooccocoecoeooo £ 8s. d. Rigor Mortis ........ op aopapeseads 10 0 0 rash AMNCHIGA .........000sce0se 15 0 0 Catalogue of Crania............ 50 0 O Didine Birds of Mascarene BREA St onc hss catdeevasesc DOS JO» 0 Typical Crania Researches ... 30 0 0 Palestine Exploration Fund... 100 0 0 £1750 13 4 lelocococococso ecooococooococecoo i) So aoc oo o'S'o'1o coocoocoocoooooco GENERAL STATEMENT. lxxxvii 8. 8 ds Secondary Reptiles, &c. ......... 30:.0°50 British Marine Invertebrate Wanna oseeeeeasiel leatecasd 100 0 0 £1940 O 0 — 1869. Maintaining the Establish- ment of Kew Observatory.. 600 Lunar Committee........0.ciscees 50 Metrical Committee..,............. 25 Zoological Record .............6+ 100 Committee on Gases in Deep- well, Waters ivmcaaseccsnatencnte 25 British) Rainfall: yecaqease tess 50 Thermal Conductivity of Iron, BEC sa Fees cioa'cwicwunrecwunianienen seen 30 Kent’s Hole Explorations...... 150 Steamship Performances ...... 30 Chemical Constitution of Oast Iron sc ccanadeeasecees senate 80 Iron and Steel Manufacture 100 Methyl Servies,.s2..stecsreseteies 30 Organic Remains in Lime- stone! Rocks: .asaeeseeeeeees 10 Earthquakes in Scotland...... 10 British Fossil Corals ......... 50 Bagshot Leaf-Beds ............ 30 Fossil Flora 25 Tidal Observations’ ............ 100 Underground Temperature... 30 Spectroscopic Investigations of Animal Substances ...... 5 Oneanic ACIds jesse ee etiae 12 Kiltorcan Fossils 20 Chemical Constitution and Physiological Action Rela- Gions f. \aeseeecade named bess 15 0 0 Mountain Limestone Fossils 25 0 0 Utilization of Sewage ......... 10 0 0 Products of Digestion ......... 10 0 0 £1622 0 0 1870. Maintaining the Establish- ment of Kew Observatory 600 Metrical Committee............ "25 Zoological Record............... 100 Committee on Marine Fauna 20 Haars’ Histies® stress) reat es: 10 Chemical Nature of CastIron 80 Luminous Meteors ............ 30 Heat in the Blood............... 15 British Rantala. ees 100 Thermal _ Conductivity of TRONS CO eset an nee, eee 20 British Fossil Corals............ 50 Kent’s Hole Explorations 150 Scottish Earthquakes ......... 4 Bagshot Leaf-Beds ............ 15 Hogs Wlorae erst cs: Oe ees 25 Tidal Observations ............ 100 Underground Temperature... 50 Kiltorcan Quarries Fossils .., 20 ooo oooococo ooo ooo =k) coooo eocoococo ooocooocoococo ooo ceooocoo ooo ooo oo oooco eoocoocococe cooooooco Ixxxviii £ 3. d. Mountain Limestone Fossils 25 0 0 Utilization of Sewage ......... 50 0 0 Organic Chemical Compounds 30 0 0 Onny River Sediment ......... 3) 10! 70 Mechanical Equivalent of PLC ibp enc soenenccnen ies adchessies 50 0 0 #1572) 0) 0 1871. Maintaining the Hstablish- ment of Kew Observatory 600 Monthly Reports of Progress yi oooco ooocowooocoo ooo So o aloooo ocoocosaocoocooo ooo IM CHEMISHT Ys, csncexscasieeeese 100 Metrical Committee............ 25 Zoological Record............... 100 Thermal Equivalents of the Oxides of Chlorine ......... 10 Tidal Observations ............ 100 IMOSSTU WHOLE *, aiviaselscgacescnie cases 25 Luminous Meteors ............ 30 British Fossil Corals: ......... 25 Heat in the Blood.........,..... 7 British! Rainfall... ..cescces cases 50 Kent’s Hole Explorations ... 150 Fossil Crustacea, ...cescscssees 25 Methyl Compounds ............ 25 BATT OD TECHS: jusccscveeecess ce 20 Fossil Coral Sections, for Photographing ..............+ 20 Bagshot Leaf-Beds ............ 20 Moab Explorations ............ 100 Gaussian Constants .........+6. 40 £1472 1872. Maintaining the LEstablish- ment of Kew Observatory 300 Metrical Committee............ 75 Zoological Record............... 100 Tidal Committee ..... Bac o0ee 200 Carboniferous Corals ......... 25 Organic Chemical Compounds 25 Exploration of Moab............ 100 Terato-Embryological Inqui- TIE Smee seceacse< aelcessceaenee seer 10 Kent’s Cavern Exploration... 100 Luminous Meteors ............ 20 Heat in the Blood............... 15 Fossil Crustacea ............008 25 Fossil Elephants of Malta... 25 AO DTC CES) vaninachenaraeste es 20 Inverse Wave-Lengths......... 20 British Rainfall.......... Speedos 100 Poisonous Substances Antago- TBISIN asco sa vennns seccenersceaeees 10 Essential Oils, Chemical Con- SUUNIHION, CGC. ) Soo ooo ooo eooooco$o ole oo So ocooococecocy[e“ oooococo REPORT—1886. £ 8. d. 1873. Zoological Record ..........+4 2 00) 0:50 Chemistry Record............+0+ 200 0 0 Tidal Committee’ ........2..s0:5 400 0 0 Sewage Committee ........... =. LOOs«0) 0 Kent’s Cavern Exploration... 150 0 0 Carboniferous Corals ......... 25 0 0 Fossil Elephants ............... 25°07 0 Wave-Lengths .............s000. 150 0 0 British Rainiiall, 5. .vsssescraress 100 0 O HSS ential OMS en cnascnnonseeweers 30 0 O Mathematical Tables ......... 100 0 0 Gaussian Constants ......... ensh LOD a) Sub-Wealden Explorations... 25 0 0 Underground Temperature... 150 0 0 Settle Cave Exploration ...... 50 0 0 Fossil Flora, Ireland............ 20 0 0 Timber Denudation and Rain- Ee meecgncnty acs odselnse ah devine 20 0 0 Luminous Meteors............+++ 30 0 0 £1685 0 0 1874. Zoological Record............... 100 0 O Chemistry Record............... 100 0 0 Mathematical Tables ......... 100 0 O Elliptic Functions............... 100 0 O Lightning Conductors ......... LO’ HOVRO Thermal Conductivity of ROCKS Sacactevicctevescssvecsecceay 10° OHO Anthropological Instructions, RCL MteN siasded tht sh 50 0 O Kent’s Cavern Exploration... 150 0 0 Luminous Meteors ............ 30 0 0 Intestinal Secretions ......... 15 00 BritishRaiotall.......sse..dess 100 0 0 HissentralfOils sc: .-..c.sncssses0ee 10° 0° 0 Sub-Wealden Explorations... 25 0 0 Settle Cave Exploration ...... 50 ‘00 Mauritius Meteorological Re- BEAUCMnssctecccssteetesssequesae 100 0 0 Magnetization of Iron ......... 20 0 0 Marine Organisms............... 30 0 0 Fossils, North-West of Scot- eiriCaeesactetasceseccc.sasnccsneem 210 0 Physiological Action of Light 20 0 0 TTAGES WMIOUS) tresceccecscs scree 25 0 0 Mountain Limestone-Corals 25 (080 HITT CRGLOCKS s crckcess sone vevaer TOD Ome Dredging, Durham and York- Shiite; COSStS mecessscacsccerseg 28 5 0 High Temperature of Bodies 30 0 0 Siemens’s Pyrometer ......... 3 6 0 Labyrinthodonts of Coal- NICASULCRerewemtesekesaca concen © Lo £1151 16 O 1875. Elliptic Functions ............ 100 0 0 Magnetization of Iron ......... 20 0 0 British Raimtall eo cspsccresers.es 120 0 0 Luminous Meteors ............ 30 0 O Chemistry Record...... pesuesate 100 0 0 GENERAL STATEMENT. £ 6&8. a. Specific Volume of Liquids... 25 0 0 Estimation of Potash and Phosphoric Acid............... 100" 0 Isometric Cresols ............... BOEEO m0) Sub-Wealden Explorations... 100 0 0 Kent’s Cavern Exploration... 100 0 0 Settle Cave Exploration ...... 50 0 0 Earthquakes in Scotland ...... 15 0 0 Underground Waters ......... 10 0 0 Development of Myxinoid Risener nttacosesscocstccat ses 20 0 0 Zoological Record............... 100 0 O Instructions for Travellers... 20 0 0 Intestinal Secretions ......... 20 0 0 Palestine Exploration ......... 100 0 O £960 O O 1876. Printing Mathematical Tables 159 4 2 british Rainfall..............-0+ 100 0 O MES UGAW «pave sus rniocccqencs edo ST (8) Tide Calculating Machine ... 200 0 0 Specific Volume of Liquids... 25 0 0 Tsomeric Cresols .............0+ 10 1:0,'0 Action of Ethyl Bromobuty- rate on Ethyl Sodaceto- BAS TANE calatit sie ctenicnass ss ches db. 1:0),0 Estimation of Potash and Phosphoric ACiG..... 0.020.000 HS. 0),10 Exploration of Victoria Cave, PIC BULOE fs ccsiccncs swan ccassicestse 100 0 0 Geological Record..............- 100 0 0 Kent’s Cavern Exploration... 100 0 0 Thermal Conductivities of "OEE. AR cha cnet REPRO ncEEa ocr 10°-0..70 Underground Waters ......... 10 0 0 Earthquakes in Scotland...... 1Lat0, 10 Zoological Record.............++ 100 0 0 PRM UTING 5. sca cccccoteoteceesees bo Or 0 Physiological ActionofSound 25 0 0 Zoological Station......... ncuron for 50) 50 Intestinal Secretions ......... 15 0 0 Physical Characters of Inha- bitants of British Isles...... 13 15 0 Measuring Speed of Ships ... 10 0 0 Effect of Propeller on turning of Steam Vessels ............ 5b AO) 10 £1092 4 4% 1877. Liquid Carbonic Acids in MEMO ALS es iii dive css deeccs 20 0 0 Elliptic Functions ............ 250 0 0 Thermal Conductivity of MAPICS! «ess. ccrasteeccaseoceness 1 7 Zoological Record.......,....+ - 100 0 0 Gent's Cavern ...:.cecsct..occes 100 0 0 Zoological Station at Naples 75 0 0 Luminous Meteors ............ 30 0 0 Elasticity of Wires ............ 100 0 0 Dipterocarpx, Report on...... 20 0 0 1886. £ ss d. Mechanical Equivalent of ELC aie screens oe eves citcinnatiness 35 0 0 Double Compounds of Cobalt and! NICKEL Aeesentet cc ==0c00s 8 0 0 Underground Temperatures 50 0 O | Settle Cave Exploration ...... 100 0 O Underground Waters in New Red Sandstone ........ .....- 10 0 0 Action of Ethyl Bromobuty- rate on Ethyl Sodaceto- ACETATE 2. ccs a dedeecsacsceses 10)10, 0 British Earthworks ............ Zot O20 Atmospheric Elasticity in Vicia... \eas ea aneettaperen cea 15 0 0 Development of Light from Codltras. . 37ers 20 0 0 Estimation of Potash and Phosphoric Acid: ...22...-sa. |) 1S, 0 Geological Record...........s«» 100 0 0 Anthropometric Committee 34.0 +O | Physiological Action of Phos- phoric Acid, &¢..2scc0-...--- Lia /07-0 £1128 9 7 1878. Exploration of Settle Caves 100 0 O | Geological Record............... 100 0 0 Investigation of Pulse Pheno- mena by means of Syphon | (omsitecord eries ca eareseceer eee 100" 0 Zoological Station at Naples 75 0 O Investigation of Underground Waterss for. cnanesdencasectte aes 15" 0° 0 Transmission of Electrical Impulses through Nerve SELUGUUNC Is. ca-actansema Cesena 30 0: 0 Calculation of Factor Table of Fourth Million............ 100 0 O Anthropometric Committee... 66 0 0 Chemical Composition and Structure of less known Alkaloidsicatatsceslstsactanaae 25.0 O Exploration of Kent’s Cavern 50 0 0 Zoological Record............... 100 0 0 Fermanagh Caves Exploration 15 0 0 Thermal Conductivity of TG GS it ones snes aaadscncasdasaent 416 6 Luminous Meteors............+++ 10,2 .0;540 Ancient Earthworks ............ 25 0 0 £725 16 6 | 1879. | Table at the Zoological Station, Naples ............... 75 0 0 Miocene Flora of the Basalt of the North of Ireland ... 20 0 0 Illustrations for a Monograph on the Mammoth ............ Liei0" 0 Record of Zoological Litera- WEST. copsneicor coed Cee pOnCEmAReL 100 0 O Composition and Structure of less-known Alkaloids ...... 25 0 0 f xe REPORT— 1 886. £8. a. Exploration of Caves in ESQUHE OS soseaeeiste-es--seoer 5. 50 0 0 Kent’s Cavern Exploration... 100 0 0 Record of the Progress of (E7of 0/2 Geo scmanocaconcadeeca 100 0 0 Fermanagh Caves Exploration 5 0 0O Electrolysis of Metallic Solu- tions and Solutions of Compound Salts............... 25 0 Anthropometric Committee... 50 0 Natural History of Socotra... 100 0 Calculation of Factor Tables for 5th and 6th Millions... 150 0 Circulation of Underground WAtGIS, cdescsavececieses. sch ace 10 0 Steering of Screw Steamers... 10 0 Improvements in Astrono- Teal CLOCKS Hasconcscetesss ioe 30. 0 Marine Zoology of South 0 ID Lexie. Sassen cpnotaraacOoe seep das 20 Determination of Mechanical Equivalent of Heat Specitic Inductive Capacity of Sprengel Vacuum......... 40 0 Tables of Sun-heat Co- CKETIUS os 2 ee cena cvaiie cio ee a=. 30 0 Datum Level of the Ordnance BLOIEV.C Vice noua cite cabies sales tasaon 10 0 Tables of Fundamental In- variants of Algebraic Forms 36 14 Atmospheric Electricity Ob- servations in Madeira ...... 15 0 Instrument for Detecting Fire-damp in Mines ......... 22 0 Instruments for Measuring the Speed of Ships ......... Li’ Tidal Observations in the English Channel ............ 10 0 £1080 11 11 1880. New Form of High Insulation LS eee ng arr Sti Sas EACABE ASC: 10 0 0 Underground Temperature... 10 0 0 Determination of the Me- chanical Equivalent of VC AT Me sualeene stein seuce oe cuers S75820 Hlasticity of Wires ............ 50° 0° 0 Luminous Meteors ............ 30 0 0 Lunar Disturbance of Gravity 30 0 0 Fundamental Invariants ...... Sa. 40 Laws of Water Friction ...... AN) tO), Specific Inductive Capacity of Sprengel Vacuum......... 20 0 0 Completion of Tables of Sun- heat Coefficients ............ 50 0 0 Instrument for Detection of Fire-damp in Mines ........ on LO OR 0 Inductive Capacity of Crystals and Paraffines © .......0cs.0« 41% 7 Report on Carboniferous BGIYZOD \ s60:s 0, ceeds coovest sae lL OeEOn 0 —_ to = or ©). 06 =) o (Je) (=) o So or) o fo) oo i=) ooo £ | Caves of South Ireland ...... 10 Viviparous Nature of Ichthyo- BAMNUS vce cceeenssscussbebasesns 10 | Kent’s Cavern Exploration... 50 Geological Record............... 100 | Miocene Flora of the Basalt of North Ireland ............ 15 Underground Waters of Per- mian Formations ............ 5 Record of Zoological Litera- WHIDTEY =, Bec ~ Seay ebae DEE oo Coe 100 Table at Zoological Station Bb Naples — 5 peseca-sacessaaeee 75 Investigation of the Geology and Zoology of Mexico...... 50 Anthropometry ............ss0.6+ 50 | BARS UAW Wecwsns. saan see 100 British POlyzOaic.eeestssceeccen 10 Naples Zoological Station ... 80 Natural History of Timor-laut 100 Conversion of Sedimentary Materials into Metamorphic HOC KG eine deenscugwenssexcsaesseee 10 Natural History of Socotra... 100 Circulation of Underground WALES: . muetreseabe eth ns 15 Migration of Birds ............ 15 Earthquake Phenomena of Japan ........ Porn aS es 25 Sil Oisiok foros Be fom sorsio. go. Loni. SO Sse tet Sia isis woes ooooooocooceco oo —) os Kimo OOo coocoececoooscso ow ocoooo SO OSes 1O:.6 — ee — Fa a) — - _ GENERAL £ 3. d. Geological Map of Europe ... 25 0 0 Elimination of Nitrogen by Bodily Exercise............... 50:00 Anthropometric Committee... 50 0 0 Photographing Ultra-Violet Spark Spectra .............-. 25 0 0 Exploration of Raygill Fis- RUPEE TDs siacsecatseresencscecess 20 0 0 Calibration of Mercurial Ther- MOMECtEIS ........+.---20000--e 20 0 0 Wave-length Tables of Spec- tra of Elements............... 50 0 0 Geological Record.........-..++- 100 0 0 Standards for Electrical | Measurements ............+++ 100 0 0 Exploration of Central Africa 100 0 0 Albuminoid Substances of BREET e ta acs seonssencsecsses 10 0 0 £1126 1 11 Jae 1883. Natural History of Timor-laut 50 0 0 British Fossil Polyzoa ......... 10 0 O Circulation of Underground DWALCTS. 22.50. .ccnsscsccecserenees 16 20,0 Zoological Literature Record 100 0 0 Exploration of Mount Kili- TNS-NYALO.....ccecceessesceseeses 500 0 0 Erosion of Sea-coast of Eng- land and Wales .............. 10 0 6 Fossil Plants of Halifax...... 20 0 0 Elimination of Nitrogen by Bodily Exercise...........-..- 38 3 3 Isomeric Naphthalene Deri- MECH aa yssccnceceoconas-essenc0 15 0 Zoological Station at Naples 80 0 Investigation of Loughton PPIs diilcie sca cess eneasoavea= 10 0 Earthquake Phenomena of PRINT e oe ner enh hs caches sends. 50 0 Meteorological Observations MBH eNINEVIS .......c.csscee0ss 50 0 Fossil Phyllopoda of Palzo- ZOIE ROCKS. 2...0.3....seasss0 25 0 Migration of Birds ............ 20 0 Geological Record............... 50 0 Exploration of Caves in South PIEPIMGIANC. oc ccscscecnscescers TOO G Scottish Zoological Station... 25 0 0 Screw Gauges............... Ssocoag) ah EAD) £1083 3 3 Abeer ee mee } 1884. _ Zoological Literature Record 100 0 BISHOP OLY 208. -2.0cse0es * More especially the ingenious and elaborate arguments of Croll deserve con- sideration; and, though I cannot agree with him in his main thesis, I gladly acknow- ledge the great utility of the work he has done. ADDRESS. 27 other they are all placed around the poles, leaving an open equatorial ocean. In the one case the whole of the land and its inhabitants would enjoy a perpetual summer, and scarcely any ice could exist in the sea. In the other the whole of the land would be subjected to an arctic climate, and it would give off immense quantities of ice to cool the ocean. But Lyell did not suppose that any such distribution as that represented in his maps had actually occurred, though this supposition has been some- times attributed to him. He merely put what he regarded as an extreme ease to illustrate what might occur under conditions less exaggerated. Sir Charles, like other thoughtful geologists, was well aware of the general fixity of the areas of the continents, though with great modifica- tions in the matter of submergence and of land conditions. The union, indeed, of these two great principles of fixity and diversity of the con- tinents lies at the foundation of theoretical geology. We can now more precisely indicate this than was possible when Lyell produced his ‘ Principles,’ and can reproduce the conditions of our con- tinents in even the more ancient periods of their history. Some examples may be taken from the history of the American continent, which is more simple in its arrangements than the double continent of Hurop-asia. We may select the early Devonian or Hrian period, in which the magni- ficent flora of that age—the earliest certainly known to us—made its appearance. Imagine the whole interior plain of North America sub- merged, so that the continent is reduced to two strips on the east and west, connected by a belt of Laurentian land on the north. In the great mediterranean sea thus produced the tepid water of the equatorial current circulated, and it swarmed with corals, of which we know no less than one hundred and fifty species, and with other forms of life appropriate to warm seas. On the islands and coasts of this sea was introduced the Erian flora, appearing first in the north, and with that vitality and colonising power of which, as Hooker has well shown, the Scandinavian flora is the best modern type, spreading itself to the south.’ A very simi- lar distribution of land and water in the Cretaceous age gave a warm and equable climate in those portions of North America not submerged, and coincided with the appearance of the multitude of broad-leaved trees of ‘modern types introduced in the early and middle Cretaceous, and which prepared the way for the mammalian life of the Hocene. We may take a still later instance from the second continental period of the later Pleisto- cene or early Modern, when there would seem to have been a partial or entire closure of the North Atlantic against the Arctic ice, and wide exten- sions seaward of the European and American land, with possibly consider- able tracts of land in the vicinity of the equator, while the Mediterranean 1 As I have elsewhere endeavoured to show (Report on Silurian and Devonian Plants of Canada), a warm climate in the Arctic region seems to have afforded the- necessary conditions for the great colonising floras of all geological periods. Gray had previously illustrated the same fact in the case of the more modern floras. ‘28 REPORT—1886. and the Gulf of Mexico were deep inland lakes.! The effect of such ‘conditions on the climates of the northern hemisphere must have been prodigious, and their investigation is rendered all the more interesting because it would seem that this continental period of the post-Glacial age was that in which man made his first acquaintance with the coasts of the Atlantic, and possibly made his way across its waters. We have in America ancient periods of cold as well as of warmth. I have elsewhere referred to the boulder conglomerates of the Huronian, of the Cambrian and Ordovician, of the Millstone-grit period of the Car- boniferous and of the early Permian; but would not venture to affirm that either of these periods was comparable in its cold with the later glacial age, still less with that imaginary age of continental glaciation assumed by certain of the more extreme theorists.2_ These ancient con- glomerates were probably produced by floating ice, and this at periods when in areas not very remote temperate floras and faunas could flourish. The glacial periods of our old continent occurred in times when the surface of the submerged land was opened up to the northern currents, drifting over it mud and sand and stones, and rendering nugatory, in so far at least as the bottom of the sea was concerned, the effects of the superficial warm streams. Some of these beds are also peculiar to the eastern margin of the continent, and indicate ice-drift along the Atlantic coast in the same manner as at present, while conditions of greater warmth existed in the interior. Even in the more recent Glacial age, while the mountains were covered with snow and the lowlands sub- merged under a sea laden with ice, there were interior tracts in some- what high latitudes of America in which hardy forest trees and her- baceous plants flourished abundantly; and these were by no means exceptional ‘interglacial’ periods. Thus we can show that while from the remote Huronian period to the Tertiary the American land occupied the same position as at present, and while its changes were merely changes of relative level as compared with the sea, these have so in- ‘fluenced the ocean currents as to cause great vicissitudes of climate. Without entering on any detailed discussion of that last and greatest Glacial period which is best known to us, and is more immediately con- nected with the early history of man and the modern animals, it may be proper to make a few general statements bearing on the relative import- ance of sea-borne and land ice in producing those remarkable phenomena attributable to ice action in this period. In considering this question it must be borne in mind that the greater masses of floating ice are pro- duced at the seaward extremities of land glaciers, and that the heavy field-ice of the Arctic regions is not so much a result of the direct freez- ing of the surface of the sea as of the accumulation of snow precipitated ? Dawkins, Popular Science Monthly, 1873. ? Notes on Post-Pliocene of Canada. Hicks, ‘ Pre-Cambrian Glaciers,” Geol. Mag., 1880. ADDRESS. 29 on the frozen surface. In reasoning on the extent of ice action, and especially of glaciers in the Pleistocene age, it is necessary to keep this fully in view. Now in the formation of glaciers at present—and it would seem also in any conceivable former state of the earth—it is neces- sary that extensive evaporation should conspire with great condensation of water in the solid form. Such conditions exist in mountainous regions sufficiently near to the sea, as in Greenland, Norway, the Alps, and the Himalayas ; but they do not exist in low arctic lands like Siberia or Grinnel-land nor in inland mountains. It follows that land glaciation has narrow limits, and that we cannot assume the possibility of great confluent or continental glaciers covering the interior of wide tracts of land. No imaginable increase of cold could render this possible, inas- much as there could not be a sufficient influx of vapour to produce the necessary condensation; and the greater the cold, the less would be the evaporation. On the other hand, any increase of heat would be felt more rapidly in the thawing and evaporation of land ice and snow than on the surface of the sea. Applying these very simple geographical truths to the North Atlantic continents, it is easy to perceive that no amount of refrigeration could produce a continental glacier, because there could not be sufficient eva- poration and precipitation to afford the necessary snow in the interior. The case of Greenland is often referred to, but this is the case of a high mass of cold land with sea, mostly open, on both sides of it, giving, there- fore, the conditions most favourable to precipitation of snow. If Green- land were less elevated, or if there were dry plains around it, the case would be quite different, as Nares has well shown by his observations on: the summer verdure of Grinnel-land, which, in the immediate vicinity of North Greenland, presents very different conditions as to glaciation and climate.! If the plains were submerged, and the Arctic currents allowed free access to the interior of the continent of America, it is conceivable that the mountainous regions remaining out of water would be covered with snow and ice, and there is the best evidence that this actually occurred in the Glacial period ; but with the plains out of water this would be im- possible? We see evidence of this at the present day in the fact that in unusually cold winters the great precipitation of snow takes place south of Canada, leaving the north comparatively bare, while as the temperature becomes milder the area of snow-deposit moves farther to the north. Thus a greater extension of the Atlantic, and especially of its cold ice- laden arctic currents, becomes the most potent cause of a glacial age. I have long maintained these conclusions on general geographical grounds, as well as on the evidence afforded by the Pleistocene deposits of Canada; and in an address the theme of which is the ocean I may be excused for continuing to regard the supposed terminal moraines of great continental) ? These views have been admirably illustrated by Von Weeickoff in the paper already referred to and in previous geographical papers. 30 REPORT—1886. glaciers as nothing but the southern limit of the ice-drift of a period of submergence. In such a period the southern margin of an ice-laden sea where its floe-ice and bergs grounded, or where its ice was rapidly melted by warmer water, and where consequently its burden of boulders and other débris was deposited, would necessarily present the aspect of a moraine, which by the long continuance of such conditions might assume gigantic dimensions. Let it be observed, however, that I fully admit the evidence of the great extension of local glaciers in the Pleistocene age, and especially in the times of partial submergence of the land. I am quite aware that it has been held by many able American geologists ! that in North America a continental glacier extended in tem- perate latitudes from sea to sea, or at least from the Atlantic to the Rocky Mountains, and that this glacier must, in many places, have exceeded a mile in thickness. The reasons above stated appear, however, sufficient to compel us to seek for some other explanation of the observed facts, however difficult this may at first sight appear. With a depression such as we know to have existed, admitting the Arctic currents along the St. Lawrence Valley, through gaps in the Laurentian watershed, and down the great plains between the Laurentian areas and the Rocky Mountains, we can easily understand the covering of the hills of Hastern Canada and New England with ice and snow, and a similar covering of the mountains of the west coast. The sea also in this case might be ice-laden and boulder-bearing as far south as 40°, while there might still be low islands far to the north on which vegetation and animals continued to exist. We should thus have the conditions necessary to explain all the anomalies of the glacial deposits. Even the glaciation of high mountains south of the St. Lawrence Valley would then become explicable by the grounding of floe-ice on the tops of these mountains when reefs in the sea. In like manner we can understand how on the isolated trappean hill of Beloeil, in the St. Lawrence Valley, Laurentian boulders far removed from their native seats to the north are perched at a height of about 1,200 feet on a narrow peak where no glacier could possibly have left them. The so-called moraine, traceable from the great Missouri Coteau in the west, to the coasts of New Jersey, would thus become the mark of theswestern and southern limit of the subsidence, or of the line along which the cold currents bearing ice were abruptly cut off by warm surface waters. I am glad to find that these considerations are beginning to have weight with Huropean geologists in their explanation of the glacial drift of the great plains of Northern Europe. Whatever difficulties may attend such a supposition, they are small compared with those attendant on the belief of a continental glacier, moving without the aid of gravity, and depending for its material on the precipitation taking place on the interior plains of a great continent. ' Report of Mr. Carvill Lewis in Pennsylvania Geological Survey, 1884; also Dana’s Manual. ADDRESS. 31 Thaveelsewhere endeavoured to show, on the evidence found in Canada, that the occurrence of marine shells, land plants, and insects in the glacial deposits of that country indicates not so much the effect of general interglacial periods as the local existence of conditions like those of Grinnel-land and Greenland, in proximity to each other at one and the same period, and depending on the relative levels of land and the distribu- tion of ocean currents and ice-drift.! T am old enough to remember the sensation caused by the delightful revelations of Edward Forbes respecting the zones of animal life in the sea, and the vast insight which they gave into the significance of the work on minute organisms previously done by Ehrenberg, Lonsdale, and Williamson, and into the meaning of fossil remains. A little later the soundings for the Atlantic cable revealed the chalky foraminiferal ooze of the abyssal ocean ; still more recently the wealth of facts disclosed by the Challenger voyage, which naturalists have not yet had time to digest, have opened up to us new worlds of deep-sea life. The bed of the deep Atlantic is covered for the most part by a mud or ooze largely made up of the débris of foraminifera and other minute organisms mixed with fine clay. In the North Atlantic the Norwegian naturalists call this the Biloculina mud. Further south the Challenger naturalists speak of it as Globigerina ooze. In point of fact it contains different species of foraminiferal shells, Globigerina and Orbulina being in some localities dominant, and in others other species, and these changes are more apparent in the shallower portions of the ocean. On the other hand there are means for disseminating coarse material over parts of the ocean-bed. There are in the line of the Arctic current - on the American coast great sand-banks, and off the coast of Norway sand constitutes a considerable part of the bottom material. Soundings and dredgings off Great Britain, and also off the American coast, have shown that fragments of stone referable to Arctic lands are abundantly strewn over the bottom along certain lines, and the Antarctic continent, otherwise almost unknown, makes its presence felt to the dredge by the abundant masses of crystalline rock drifted far from it to the north. These are not altogether new discoveries. I had inferred many years ago, _ from'stones taken up by the hooks of fishermen on the banks of New- _ foundland, that rocky material from the north is dropped on these banks by the heavy ice which drifts over them every spring, that these stones are glaciated, and that after they fall to the bottom sand is drifted over them with sufficient velocity to polish the stones and to erode the shelly cover- ings of Arctic animals attached to them.? If then the Atlantic basin were upheaved into land we should see beds of sand, gravel, and boulders with clay flats and layers of marl and limestone. According to the * Notes on Post-Pliocene of Canada,1872. One well-marked interval only has been established in the glacial deposits of Canada. 2 Notes on Post-Pliocene of Canada, 1872. 32 REPORT—1 886. Challenger Reports, in the Antarctic seas 8. of 64° there is blue mud with fragments of rock in depths of 1,200 to 2,000 fathoms. The stones, some: of them glaciated, were granite, diorite, amphibolite, mica schist, gneiss, and quartzite. This deposit ceases and gives place to Globigerina ooze and red clay at 46° to 47° S., but even further north there is sometimes as much as 49 per cent. of crystalline sand. In the Labrador current a block of syenite weighing 490 lbs. was taken up from 1,340 fathoms, and in the Arctic current 100 miles from land was a stony deposit, some stones being glaciated. Among these were smoky quartz, quartzite, limestone, dolomite, mica schist, and serpentine; also particles of monoclinic and triclinic felspar, hornblende, augite, magnetite, mica, and glauconite, the latter no doubt formed in the sea-bottom, the others drifted from Hozoic and Paleozoic formations to the north.! A remarkable fact in this connection is that the great depths of the sea are as impassable to the majority of marine animals as the land itself. According to Murray, while twelve of the Challenger’s dredgings taken in depths greater than 2,000 fathoms gave 92 species, mostly new to science, a similar number of dredgings in shallower water near the land gave no less than 1,000 species. Hence arises another apparent paradox relating to the distribution of organic beings. While at first sight it might seem that the chances of wide distribution are exceptionally great for marine species, this is not so. Hxcept in the case of those which enjoy a period of free locomotion when young, or are floating and pelagic, the deep ocean sets bounds to their migrations. On the other hand the spores of cryptogamic plants may be carried for vast distances by the wind, and the growth of volcanic islands may effect connections which, though only temporary, may afford opportunity for land animals and plants to pass over. . With reference to the transmission of living beings across the Atlantic, we have before us the remarkable fact that from the Cambrian age on- wards there were on the two sides of the ocean many species of inver- tebrate animals which were either identical or so closely allied as to be possibly varietal forms.? In like manner the early plants of the Upper Silurian, Devonian, and Carboniferous present many identical species ; but this identity becomes less marked in the vegetation of the more modern times. Hven in the latter, however, there are remarkable connections between the floras of oceanic islands and the continents, which establish this conclusively. Thus the Bermudas, altogether recent islands, have been stocked by the agency chiefly of the ocean currents and of birds, with nearly 150 species of continental plants, and the facts collected by Helmsley as to the present facilities of transmission, along with the evidence ‘afforded by older oceanic islands which have been receiving 1 General Report, ‘ Challenger’ Expedition. 2 See Davidson’s Monographs on Brachiopods; Etheridge, Address to Geological Society of London; Woodward, Address to Geologists’ Association; also Barrande’s ere a 2 ADDRESS. 33 animal and vegetable colonists for longer periods, go far to show that, time being given, thesea actually affords facilities for the migration of the inhabitants of the land, comparable with those of continuous continents. In so far as plants are concerned, it is to be observed that the early forests were largely composed of cryptogamous plants, and the spores of these in modern times have proved capable of transmission for great distances. In considering this we cannot fail to conclude that the union of simple cryptogamous fructification with arboreal stems of high complexity, so well illustrated by Dr. Williamson, had a direct relation to the neces- sity for a rapid and wide distribution of these ancient trees. It seems also certain that some spores, as, for example, those of the Rhizocarps,! a type of vegetation abundant in the Paleozoic, and certain kinds of seeds, as those named Aitheotesta and Pachytheca, were fitted for flotation. Farther, the periods of Arctic warmth permitted the passage around the northern belt of many temperate species of plants, just as now happens with the Arctic flora; and when these were dispersed by colder periods they marched southward along both sides of the sea on the mountain chains. The same remark applies to northern forms of marine invertebrates, which are much more widely distributed in longitude than those farther south. The late Mr. Gwyn Jeffreys, in one of his latest communications to this Association, stated that 54 per cent. of the shallow-water mollusks of New England and Canada are also European, and of the deep-sea forms 30 out of 35; these last of course enjoying greater facilities for migration than those which have to travel slowly along the shallows of the coasts in order to cross the ocean and settle themselves on both sides. Many of these animals, like the common mussel and sand-clam, are old settlers which came over in the Pleistocene period, or even earlier. Others, like the common periwinkle, seem to have been slowly extending themselves in modern times, perhaps even by the agency ofman. The older immigrants may possibly have taken advantage of lines of coast now submerged, or of warm periods, when they could creep around by the Arctic shores. Mr. Herbert Carpenter and other natu- ralists employed on the Challenger collections haye made similar state- ments respecting other marine invertebrates, as, for instance, the Echino- derms, of which the deep-sea crinoids present many common species, and my own collections prove that many of the shallow-water forms are common. Dall and Whiteaves? have shown that some mollusks and Echinoderms are common even to the Atlantic and Pacific coasts of North America; a remarkable fact, testifying at once to the fixity of these Species and to the manner in which they have been able to take advantage of geographical changes. Some of the species of whelks common to the Special Memoirs on the Brachiopods, Cephalopods, §c.; and Hall, Paleontology of New York; Billings, Reports on Canadian Fossils; and Matthews, Cambrian of New Brunswick, Trans. R.S.C. * See paper by the author on Palzozoic Rhizocarps, Chicago Trans. 1886. * Dall, Report on Alaska; Whiteaves, Trans. R.S.C. 1886. D 34 : REPORT—1886 . Gulf of St. Lawrence and the Pacific are animals which have no special locomotive powers even when young, but they are northern forms not proceeding far south, so that they may have passed through the Arctic seas. In this connection it is well to remark that many species of animals have powers of locomotion in youth which they lose when adult, and that others may have special means of transit. I once found at Gaspé a specimen of the Pacific species of Coronula, or whale-barnacle, the O. regine of Darwin, attached to a whale taken in the Gulf of St. Lawrence, and which had probably succeeded in making that passage around the north of America, which so many navigators have essayed in vain. But it is to be remarked that while many plants and marine inverte- brates are common to the two sides of the Atlantic, it is different with land animals, and especially vertebrates. I do not know that any Paleozoic insects or land snails or millipedes of Europe and America are specifically identical, and of the numerous species of*batrachians of the Carboniferous and reptiles of the Mesozoic all seem to be distinct on the two sides. The same appears to be the case with the Tertiary mammals, until in the later stages of that great period we find such genera as the horse, the camel, and the elephant appearing on the two sides of the Atlantic ; but even then the species seem different, except in the case of a few northern forms. Some of the longer-lived mollusks of the Atlantic furnish suggestions which remarkably illustrate the biological aspect of these questions. Onur familiar friend the oyster is one of these. The first known oysters appear in the Carboniferous in Belgium and in the United States of America. In the Carboniferous and Permian they are few and small, and they do not culminate till the Cretaceous, in which there are no less than ninety-one so-called species in America alone ; but some of the largest known species are found in the Hocene. The oyster, though an inhabitant of shallow water, and very limitedly locomotive when young, has sur- vived all the changes since the Carboniferous age, and has spread itself over the whole northern hemisphere.! T have collected fossil oysters in the Cretaceous clays of the coulées of Western Canada, in the Lias shales of England, in the Eocene and Cre- taceous beds of the Alps, of Egypt, of the Red Sea coast, of Judea, and the heights of Lebanon. Everywhere and in all formations they present ferms which are so variable and yet so similar that one might suppose all the so-called species to be mere varieties. Did the ‘oyster originate separately on the two sides of the Atlantic, or did it cross over so promptly that its appearance seems to be identical on the two sides? Are all the oysters of a common ancestry, or did the causes, whatever they were, which introduced the oyster in the Carboniferous act over again in later periods? Who can tell? ‘This is one of the cases where 1 White, Report U.S. Geol. Survey, 1882-83. ADDRESS. ao causation and development—the two scientific factors which constitute the _ basis of what is vaguely called evolution—cannot easily be isolated. I would recommend to those biologists who discuss these questions to addict themselves to the oyster. This familiar mollusk has successfully pur- sued its course and has overcome all its enemies, from -the flat-toothed ‘selachians of the Carboniferous to the oyster-dredgers of the present day, has varied almost indefinitely, and yet has continued to be an oyster, unless indeed it may at certain portions of its career have temporarily assumed the disguise of a Gryphea or an Exogyra. The history of such an animal deserves to be traced with care, and much curious information _ respecting it will be found in the report which I have cited. | But in these respects the oyster is merely an example of many forms. Similar considerations apply to all those Pliocene and Pleistocene mollusks which are found in the raised sea-bottoms of Norway and Scotland, on the top of Moel Tryfaen in Wales, and at similar great heights on the hills of America, many of which can be traced back to early Tertiary times, and can be found to have extended themselves over all the seas of the northern hemisphere. They apply in like manner to the ferns, the conifers, and the angiosperms, many of which we can now follow without even specific change to the Eocene and Cretaceous. They all show that the forms of living things are more stable than the lands and seas in which they live. If we were to adopt some of the modern ideas of evolution we might cut the Gordian knot by supposing that, as like causes can produce like effects, these types of life have originated more than once in geological time, and need not be genetically connected with each other. But while evolutionists repudiate such an application of their doctrine, however natural and rational, it would seem that nature still more strongly repudiates it, and will not allow us to assume more than one origin for one species. Thus the great question of geographical distribution remains in all its force, and, by still another of our geologi- _ ¢al paradoxes, mountains become ephemeral things in comparison with the delicate herbage which covers them, and seas are in their present extent but of yesterday when compared with the minute and feeble _ organisms that creep on their sands or swim in their waters. The question remains, Has the Atlantic achieved its destiny and finished its course, or are there other changes in store for it in the _ future? The earth’s crust is now thicker and stronger than ever before, and its great ribs of crushed and folded rock are more firm and rigid than in any previous period. The stupendous voleanic phenomena mani- -fested in Mesozoic and early Tertiary times along the borders of the Atlantic have apparently died out. These facts are in so far guarantees of permanence. On the other hand, it is known that movements of elevation along with local depression are in progress in the Arctic regions, and a great weight of new sediment is being deposited along the borders of the Atlantic, especially on its western side, and this is not improbably con- nected with the earthquake shocks and slight movements of depression D2 - : yi 36 REPORT—1886. which have occurred in North America. It is possible that these slow and secular movements may go on uninterruptedly, or with occasional paroxysmal disturbances, until considerable changes are produced. It is possible, on the other hand, that after the long period of quiescence which has elapsed there may be a new settlement of the ocean-bed, accompanied with foldings of the crust, especially on the western side of the Atlantic, and possibly with renewed volcanic activity on its eastern margin. In either case a long time relatively to our limited human chro- nology may intervene before the occurrence of any marked change. On the whole the experience of the past would lead us to expect movements and eruptive discharges in the Pacific rather than in the Atlantic area. It is therefore not unlikely that the Atlantic may remain undisturbed, unless secondarily and indirectly, until after the Pacific area shall have attained to a greater degree of quiescence than at present. But this subject is one too much involved in uncertainty to warrant us in following it farther. In the meantime the Atlantic is to us a practically permanent ocean, varying only in its tides, its currents, and its winds, which science has already reduced to definite laws, so that we can use if we cannot regulate them. It is ours to take advantage of this precious time of quietude, and to extend the blessings of science and of our Christian civilisation from shore to shore until there shall be no more sea, not in the sense of that final drying-up of old ocean to which some physicists look forward, but in the higher sense of its ceasing to be the emblem of unrest and disturb- ance, and the cause of isolation. I must now close this address with a short statement of some general truths which I have had in view in directing your attention to the geo- logical development of the Atlantic. We cannot, I think, consider the topics to which I have referred without perceiving that the history of ocean and continent is an example of progressive design, quite as much as that of living beings. Nor can we fail to see that, while in some im- portant directions we have penetrated the great secret of Nature, in refer- ence to the general plan and structure of the earth and its waters, and the changes through which they have passed, we have still very much to learn, and perhaps quite as much to unlearn, and that the future holds out to us and to our successors higher, grander, and clearer conceptions than those to which we have yet attained. The vastness and the might of ocean and the manner in which it cherishes the feeblest and most fragile beings, alike speak to us of Him who holds it in the hollow of His hand, and gave to it of old its boundaries and its laws ; but its teaching ascends to a higher tone when we consider its origin and history, and the manner in which it has been made to build up continents and mountain-chains, and at the same time to nourish and sustain the teeming life of sea and land. ee Oe REPORTS ON THE STATE OF SCIENCE. oh vin 1 een Series E§ ws oy mr — = ae. .- ; Beet tae ; A « Psi ae # ew abbas Se: JP. a, IX é Tees aw ae wy — Rear .* th Ae | ) ai a oe g ae ne cts. Baal rag + esa Beatie ae ~ Ae At | eee ON X= io 2 Mae re x ica ey ee . ne oa) eae Pele + ee eee Se se (areas ae (ipeg-bx eal Esc ne bi SHeene site ; ae bes cat hid —_= as REPORTS ON THE STATE OF SCIENCE. Second Report of the Committee, consisting of Professor G. ForBES (Secretary), Captain Asyry, Dr. J. Hopkinson, Professor W. G. Apams, Professor G. C. Foster, Lord Rayieren, Mr. Preecr, Pro- fessor ScuvusteR, Professor Dewar, Mr. A. Vernon .Harcourt, Professor Ayrton, and Sir James Dovug.ass, appointed for the purpose of reporting on Standards of Light. Drawn wp by Professor G. ForBEs. THe Committee on Standards of Light met repeatedly during last winter. It had been proposed in last year’s report to carry on experi- ments on electrical standards in the hope of arriving at an absolute standard of light. One of the first steps was to discover a means of re- producing a definite temperature, and certain experiments were proposed for this purpose. At one of the first meetings of the Committee Captain Abney announced that he had already found a means of doing this in a _ different manner from that proposed in the Committee’s report and de- _ pending only upon the change of resistance of the carbon filament. Under these circumstances the Committee left this part of the experimental in- vestigation to be reported upon by Captain Abney. His further researches have, however, led him to believe that the Jaw which he had announced to the Committee does not hold with all qualities of carbon filament. He has, however, been engaged upon further experimental researches, which are almost ready for publication, and which have an important bearing upon the labours of the Committee. In last year’s report attention was drawn to the value of the Pentane standard of Mr. Vernon Harcourt as a practical reproducible standard, and Mr. Rawson has been since then engaged in a further examination of this standard. Sir James Douglass has also made some experiments which are not quite completed, but have gone so far as to give great pro- mise. Some account of these experiments in this report had been ex- pected by the Committee, but the absence of Sir James Douglass on official business has interfered with this. At one of the first meetings of the Committee the Secretary showed _ what he had done in the way of improving thermopiles such as it was hoped would be of use in the investigations recommended in last year’s 40 REPORT—1886. report ; and he was instructed by the Committee to proceed with the construction of the instrument, which has been completed, and is placed before the Section and described in a separate paper. The Committee respectfully request to be reappointed, with a grant of 251. Report of the Committee, consisting of Professor G. H. Darwin, Sir W. Tuomson, and Major Batrp, for preparing instructions for the practical work of Tidal Observation; and Fourth Report of the Committee, consisting of Professors G. H. DARWIN — and J. C. Apams, for the Harmonic Analysis of Tidal Observa- tions. Drawn up by Professor G. H. Darwin. I. Recorp or WoRK DURING THE PAST YEAR. Datum LEVELS. Masor Barrp’s manual of tidal observations is now printed, and will be sold by Messrs. Taylor & Francis, Fleet Street. The Indian tidal results of all previous years, and those given in the various Reports to the British Association, have been reduced by Major Baird to the standard form recommended in the Report of 1883. To these have been added the results derived by the United States Coast Survey, and the whole has been published in the ‘ Proceedings of the Royal Society,’ No. 239, 1885, in a paper by Major Baird and Professor Darwin. In the course of the Indian tidal operations a discussion has arisen as to the determination of a datum level for tide-tables. The custom of the Admiralty is to refer the tides to ‘the mean low-water mark of ordinary spring tides.’ This datum has not a precise scientific meaning, but, at ports where there are but few observations, has been derived from a mean of the spring-tides available. At some of the Indian ports this datum has been found by taking the mean of all spring-tides on the tide diagram for a year, with the exception of those which occur when the moon is near perigee. The diurnal tides enter into the determination of the datum in an undefined manner. It follows that two determinations of this datum level, both equally defensible, might differ sensibly from one another. A datum level should be ‘sufficiently low to obviate the frequent occurrence of negative entries in a tide-table, and it should be rigorously determinable from tidal theory. It is now proposed to adopt as the datum level at any new ports in India, for which tide-tables are to be issued, a datum to be called ‘the Indian spring low-water mark,’ and which is to be below mean sea-level by the sum of the mean semi-ranges of the tides M,, S., K,, O; or, in the notation used below, H,,+H,+H’+H, below mean water mark. This datum is found to agree pretty nearly with the Admiralty datum, but is usually a few inches lower. The definition is not founded on any precise theoretical considerations, but it satisfies the conditions of a good datum, and is precisely referable to tidal theory. If, when further observations are made, it is found that the valnes of the several H’s require correction, it is not proposed that the datum level shall be altered accordingly, but when once fixed it is to be always adhered to. ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 41 TL On tar TREATMENT oF A SHorT SERIUS OF TiDAL OBSERVATIONS AND ON TIDAL PREDICTION. $1. Harmonic Analysis. Having been asked to write an article on the tides in a new edition of the ‘ Admiralty Scientific Manual,’ now in the press, I thought it would ‘be useful to show how harmonic analysis might be applied to the reduc- tion of a short series of tidal observations, such as might be made when a :. ship lies for a fortnight or a month in a port. The process of harmonic analysis, as applicable to a year of continuous observation, needs some modification for a short series, and as it was not possible to explain the reasons for the rules laid down within the limits of the article, it seems desirable to place on record an explanation of the ‘instructions given. The observations to be treated are supposed to consist of hourly ob- ‘servations extending over a fortnight or a month. In the reduction of a long series of observations the various tides are disentangled from one another by means of an appropriate grouping of the hourly observations. When, however, the series is short, the method of grouping is not suffi- -cient in all cases. With the amount of observation supposed to be available, a determina- tion of the elliptic tides was not possible, and it was therefore proposed to consider only the tides M,, S, K,, K,, O, P—that is to say, the principal Innar, solar, and luni-solar semidiurnal tides, and the luni-solar, lunar, _-and solar diurnal tides. The luni-solar and solar semidiurnal tides have, however, so nearly the same speed that we cannot hope for a direct separation of them by the grouping of the hourly values, and we must have recourse to theory for completing the process ; and the like is true -of the luni-solar and solar diurnal tides. Also, the tides K, and P have very nearly half the speed of S,; hence _ the diurnal tides K, and P will appear together as the diurnal constituent, whilst S, and K, will appear as the semi-diurnal constituent, from the harmonic analysis of the same table of entries. It thus appears that three different harmonic analyses will suffice to -determine the six tides, viz. :— First, an analysis for M, ; second, an analysis for O ; third, an analysis for S,, K,, Kj, P. The rules therefore begin with instructions for drawing up three _ schedules, to be called M, O, S, for the entry of hourly tide-heights. _ Each schedule consists of twenty-four hour columns, and a number of _ rows for the successive days. In M and O certain squares are marked, in which two successive hourly entries are to be put. The instructions for drawing up the schedules are simply rules for preparing part of the first page of the series M, O, S of the computation forms for a year of observation. In order to minimise the vitiation of the results derived from the M sheet by the S, tide, and vice versd, and similarly to minimise the vitiation of the results from the O sheet by the K, fide, itis important to choose the proper number of entries in each of the three sheets. It was shown in Section III. of the Tidal Report to the British Asso- ciation for 1885 how these periods were to be determined. The equation 42 REPORT—1886. . by which we find how many rows to take to minimise the effect of the S, tide on the M, tide is there shown to be 1°0158958q¢=14°-4920521r. If r=1, q=14'26 ; and if r=2, g=28°5. From a reason similar to that given in 1885 we conclude that, in analysing about a fortnight of observation we must have 14 rows of values on the M sheet, and for a month’s observation 29 rows of values. Similarly, to minimise the effect of the M, tide on the S, tide the equation is 1°-0158958g=15°r. Tf r=1, gq=14'76; and if r=2, g=29°5. Whence we must have 15.rows of values on the S sheet for a fort- night’s observation, and 30 rows of values for a month’s observation. These two rules are simply a statement that on the M and § sheets we are to take a period equal to the interval from spring-tide to spring-tide, or twice that period. Similarly, to minimise the effect of the K, tide on the O tide, the equation is 1°:0980330q=13°'9430356r. If r=1, g=12°69; and if r=2, q=295°38. Whence we mast have 13 rows of values on the O sheet for a fort- night’s observation, and 25 rows for a month’s observation. Lastly, to minimise the effect of the O tide on the K, tide, the equa- tion is 1°:0980330g=15°:0410686r. Ifr=1, g=13°70; and if r=2, gq=26°4. Hence, in using the numbers on the S sheet for determining the diurnal tides, we must use 14 rows of values for a fortnight’s observation, and 26 rows for a month’s observation. Thus, on the S sheet we use more rows for the semidiurnal tides than for the diurnal—namely, one more for a fortnight and three more for a month. The rules for drawing up the computation forms then specify, in accordance with the above results, where the entries are to stop on the three sheets, and give directions for the dual use of the S sheet, according as it is for finding semidiurnal or diurnal tides. When the entries have been made, the twenty-four columns on each sheet are summed, and each is divided by the number of entries in the column. On the S sheet there are two sets of sums and divisions, one with and the other without the additional row or rows. The three sheets thus provide us with four sets of twenty-four mean hourly values; the M sheet corresponds with mean lunar time, the hour being 1514-49 ofa mean solar hour ; both the means on the S sheet corre- spond with mean solar time ; and the O sheet corresponds witha special time, in which the hour is 15+13-°94 of a mean solar hour. The four sets of means are then submitted to harmonic analysis: the semidiurnal components are only evaluated on the M sheet; the diurnal components are evaluated from the shorter series on S, and the semi- diurnal from the longer series ; and the diurnal components from the O sheet. We may also evaluate the quaterdiurnal components from the M and S sheets. | ; | — se ——-”-— ci ie ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. ~- 43. It might, perhaps, be useful to evaluate the diurnal component on the M sheet, for if it does not come out small it is certain that the amount of observations analysed is not sufficient to give satisfactory results. In the article the Larmonic analysis is arranged according to a rule devised by General Strachey, which is less laborious than that usually employed, and which is sufficiently accurate for the purpose. § 2. On the Notation employed. It will be convenient to collect together the definitions of the prin-. cipal symbols employed in this paper. The mean semi-range and angle of lagging of each of the harmonic constituent tides have, in the Tidal Report for 1883, been denoted gene- rically by H, «; but when several of the H’s and «’s occur in the same algebraic expression it is necessary to distinguish between them. The tides to which we shall refer are M,, S., N, L, T, R, O, P, and K,, K, ; the H and « for the first eight of these will be distinguished by writing the suffix letters ,,, ., », &c., ¢.g., Hn, ‘m for the M, tide. With regard to the K tides, we may put H”, «’’, and H’, «’. Again, the factors of augmentation f (functions of longitude of moon’s node), as applicable to the several tides, will be denoted thus :—for M,, N, L, simply f; for K,, K,, f’, f’ respectively ; for O, f,. The K,, K, tides take their origin jointly from the moon and sun, and it ' will be necessary in computing the tide-table to separate the lunar from the = b solar portion of K,. Now, the ratio of the lunar to the solar tide-generat- ing force is such that ‘683H” is the lunar portion and ‘317H”’ is the solar portion of H”, In the Report of 1885 a slightly different notation was employed for the H’s and «’s, but it is easy to see how the results of that Report are to be transformed into the present notation. As in the Report of 1883, we write ¢, h,s for local mean solar hour- angle, sun’s and moon’s mean longitude, and », , »’, 2»’’ for functions of the longitude of moon’s node depending on the intersection of the equator with the lunar orbit; also y—», », c, a are the hourly increments of f, h, s and longitude of moon’s perigee, and e,e, the eccentricities of lunar and solar orbits. Let p, p, denote the cubes of the ratios of the moon’s and sun’s paral- _laxes to their mean parallaxes; 6, 6, the moon’s and sun’s declinations ; p’ the value of p at a time tan («,,—«,)/(e—a), or 105"°3 tan (kKy—K,) earlier than ¢; 0’ the moon’s declination at a time tan («/—«,,.)/20, or 522-2 tan («x’—x,,) earlier than ¢. Let P, P,, P’ be the cube roois of p, p, p’. Let A, A, be declinations such that cos*A, cos?A, are respectively the mean values of cos*0, cos?6,: obviously A has a small inequality with the longitude of the moon’s node. Let ¢ be an auxiliary angle defined by H,, sin «,—H, sin 4 tan Se OD oe ae H,, cos e,—H, cos Lastly, let /, ¥, be the moon’s and sun’s local hour angles. A4 REPORT—1886. § 3. The Reduction of the Results of Harmonic Analysis. We now suppose the harmonic analysis of the hourly means on the three sheets M, O, S completed. The deduction of H,,, «,, and H,, «, from the M and O sheets follows exactly the same rules as in a long series of observations, and the reader is referred to the Report of 1885 for an explanation. With regard tothe S sheet, the results of the harmonic analysis do not separate the S, tide from the K, tide, nor the K, tide from the P tide, and we have to employ theoretical considerations for effecting the separation. The semidiurnal tides will be taken first. The solar tide, as derived from a short series of observations, is of course affected by the sun’s parallax, and as the sun changes his parallax slowly, the solar tide will follow the equilibrium law and vary as the cube of the sun’s parallax. Thus the height of the purely solar semidiurnal tide as derived from our short series of observations will be p,H, instead of H,, and this will be fused with the luni-solar tide Ky. The schedules of the Report of 1883 thus show that we shall have as the expression for this tide, compounded of §, (with parallactic inequality) and Ky, hy = p/H, cos (2t—«,) +f!" H” cos (2¢4+2h—2"—x"’) . : (1) The theoretical ratio of H” to H, is (see Schedule EH, 1883) that of “12662 to 45631, or 1 to 3°67; and the tides having nearly the same speed, we may assume «//=«,. Hence: ert fae Pi 2 [p. cos (2t—k,) +c cos (2¢+2h— 20" —«,)| ==, cos (2t—«,--W)) si 9) ie Peeeae ar tle eee ee § f” sin 2(h—v'’) 3°67p,+f” cos 2(h—v'’) S67 af cos l(b) Sa a aoe If, therefore, the harmonic analysis of the S sheet for semidiurnal tides has given the two components A», B, which are to define R,, ¢, by the equations where R= A,=R, cosZ,, B,=R, sin Z,; and if we put for p, its value at the middle of the fortnight or month as a mean value, and also put as a mean h= ©, the value of the sun’s mean longitude at the middle of the fortnight or month, we get 3°67 cos wv H=3-67p,4+f" cosk(O—y hth f”’ sin 2(@ —v"’) Pai s p, +f" cos 2(@ —")’ and H! =3.67Hs «aene ae We now turn to the diurnal tides derived from the S sheet. The schedules of the Report of 1883 show that we shall have as the expression for the tide which is compounded of K, and P h,=f'H’ cos (t¢+h—»!—1r—«') +H, cos (t—h+37—K,) . . . (85) The theoretical ratio of H, to H’ is (see Sched. E 1883) that of 19317 -where tan v=3.67 ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 45 to 58385, or 1 to 3, and the tides having nearly the same speed, we may assume k,—=«,. Hence: h=H {('f' cos (¢-+h—v'—5r—nx') —3 cos [f+ h—9! —hn—«' —(2h—y)]} =R’ cos (t+h—v/—}r—«' +9), sin (2h—v’) 3f’—cos (2h—v’) where tan $=3F7— cos Qh—v')’ A ecuniee eoeiaiivles i vey on (6) If, therefore, the harmonic analysis for diurnal tides has given the two components A,, B, which are to define R’, ¢’ by the equations A,=R' cos Z’, B,=R/ sin?’ and if we write V’=h,—v'—4z, where h, is the sun’s mean longitude at the beginning of the observations, and if we put © for the value of the sun’s mean longitude at the middle of the fortnight or month, we get 3 cos } 3f —cos (2 © —r’)’ _ ysin (20 —r’) 3f'—cos (20 —>’) In the article in the ‘ Admiralty Manual’ these rules are applied to a series of observations at Port Blair, Andaman Islands, commencing 0" April 19, 1880, and extending over a fortnight. The observations are taken from a tide-curve registered by a gauge, and were supplied to me by Major Baird." The result of the reduction is as follows :— H= =’ +V' +9, where tan ¢= y > ET EE ee! San CD Resvtts or Harmonic ANALYSIS OF 15 DAYS’ HOURLY OBSERVATIONS AT Port Brarr, commencine 02, Aprit 19, 1880. Mean of Three Years’ Hourly Observation. AS ais: : : d ; . 4740 ft. M beers i i ela : : F , . 2°022 ft. 2) km = 280° : ‘ ‘ : : a are? R & ==) 076 I ee : ; 2 ‘ 20968. ft: 0) ergs Eg : ; : ! : . 815° K foe O09 fi", 4 : : J i . 0-282 ft. 2) 2 = 814° i ; . 5 : 2” wally? K W = 046%. .. ; 3 : ; Une g ike 1) 2 = 827° = - : “ «peed? P te =: 5) ft.) -. : ‘ . : . 0134 ft. a aan : ‘ : 5 ; » “326° 0 fH OAT. ; ‘ , : - 0-160 ft. fe = 209" ‘ . . : : ~ 1 O22 The second column is inserted for the sake of comparison, and gives the results of three years of continuous hourly observation by the tidal 1 Only one place of decimals of a foot was used. In the Indian tidal operations the heights are measured to two places. The second place of decimals was at one time given up, but the computers having got used to the two decimal figures, it was found that there was actually some loss of time in giving up the second place. 46 REPORT—1886. department of the Survey of India. An error of 2° in the value of x, corresponds to an error of only 4” in the time of high and low water. The concordance between the two affords evidence of the utility of even so short a series of observations as during a fortnight. § 4. Computation of a Tide-iable. Semidiurnal Tides. The computation of a tide-table from tidal constants which do not contain the elliptic tides N and L presents some difficulty, because the total neglect of these tides would make the results very considerably in error. On this account it was found necessary to use the moon’s hour- angle, declination, and parallax in making the computations. We shall begin by considering only the semidiurnal tide. In the Tidal Report of 1885 it was shown how the expression for this tide in the harmonic notation may be transformed so as to involve hour- angles, declinations and parallaxes, instead of mean longitudes and eccen- tricities of orbits. The formula (27) of the Report of 1885 for the total semidiurnal tide, hie written in the notation of § 2 is a : nt cos (2W—«,,) +H, cos (20,—x.) cos* 6/—cos? A aay *683H” cos (2N—«’’) cos? ¢, —cos? A aaa ee cos (2b,—x'’) sin 6 cos 0 dé °683H” : ~ sin? A, dt \cos («—«,,) — H, tan’, ) sin Gt tn) cos? A, 1 H,, cos «,— H, cos x Gaeta =) ecose +(P,—1) eae cos (2,—«.) --cos’A wa A= H,, sec (km—*,) + H, see (;—k,) cos?A, o—a@ € We shall now proceed to simplify this. In the first place, the terms depending on dd/dt and dP/dt are certainly small, and may be neglected. os (2—e) )sin (24a) (8) Then let 2A cos? 6’! —cos? A =x Unt ein, -683H" 008 («!’—Key) / cos? A H,, cos x, — H, cos t, cos? A, Cs) €cos € COs (€—Kn), cos? 6! —cos? A : petnt ot eae 4 .683H” sin (k/’—k,,) / - os? A H,, cos «,—H,cosm , cee ce) pee ig Se aie (emnj cos” A € COSE fi a, M=8,+ 4, S17H"4+(P,-1 A ee a ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 47 Now, observation and theory agree in showing that «” is very nearly equal to x,; hence we are justified in substituting «, for «’’ in the small solar declinational term of (8) involving ‘317H”. This being so, (8) becomes hg=M cos (2¥—p)+M,cos(2—,) . . . . . (10) In the equilibrium theory each H is proportional to the corresponding term in the harmonically developed potential. This proportionality holds nearly between tides of nearly the same speed ; hence in the solar tides we may assume (see Sched. B, 18838, and note that cot? A,=}cot? dw) that, cos? A, 1 =e S/H" =3., (H,—H,)=H,, and M, reduces to cos? é cos? 6 g VM = a A H,+3(P,—1) H.= ae aH: [1+3(P/—1)] nearly cos? 6 ee oo AE F iaccigichow hls hf debtbide Gate OD Now, since 4,=16°'36=16° 22’, sec? A,=1:086, also P3=p,, and there- fore Mj=1086p pcos" 3; Hiayetat Ys cours Gases wf (12) In a similar way, according to the equilibrium theory, we should have 1 35 (HH) =H. Although this proportionality is probably not actually very exact, yet in our supposed ignorance of the lunar elliptic tides we have to assume its truth. Also, we must assume that the two elliptic tides N and L suffer the same retardation, and therefore c,=,=«. With these assumptions, H,, cos k, — Hy cos x; € COS E H,,+(P’—1) Then, since cos (e—«,,)=H,,[1+3(P/—1)]=H,,P’. 2 cos” A ab de cos? A, ‘we have M=fp’ A, SS © .683H" c08 (c"—k,), | pig ee 85H" sin (1g) de. (18) If we put . sya = ygary X87", en log C,="6344, log C.=2°3925, and C,, C, are absolute constants for all times and places. 48 REPORT—1886. Next, if we put a=C,H" cos (k”—k,), [B=C.H” cos (”—«,), A=a cos 2A web COSAge te. te then obviously a, 3 are absolute constants for the port, and A and B are nearly constant, for their small variability only depends on the longitude of the moon’s node entering through A. Thus we have, from (9), (12), (13), (14), M =fH,, + (p’—LfHy + (a cos 24 —A), }t =k,+(f cos 20'—B), expressed in degrees, M,=1-086p, cos? 6/H.,, aaa es SON, eae (15) where p’, 6’ are the values of p and 6 at a time earlier than that corre- sponding to ~ by ‘the age’ 52-2 tan («”’ —«,). In the article fH,,, is called R,,; (p’—1)fH,, the parallactic correction, is called 6,R,,; (a cos 20’—A), the declinational correction, is called 6,R,,. Similarly, 3 cos 28/—B, the declinational correction to «,,, is called dgK,- Also, M, is called 8. Thus, with this notation the whole semidiurnal tide is ho= (Bint 21 +32Rq) 008 (2) — kin — Bohm) +8 cos (2),—K,) - (16) The mean rate of increase of Wis y—s, or 14°49 per hour; hence the interval from moon’s transit to lunar high water is approximately a5(&m+69%m) hours, when «,, is expressed in degrees. If 7 be the mean interval, and 0,7 its declinational correction, i+ dot =pokntaydokm . . . . . . . (17) Now, let A be twice the apparent time of moon’s transit reduced to angle at 15° per hour, or the apparent time reduced at 30° per hour, Then the excess of the moon’s over the sun’s R.A. at lunar high water is $A plus the increase of the difference of R.A.’s in the interval 7. This =", and at lunar high water the sun’s hour- : : . 17 increase is approximately 5 angle is given by 2b = 2b +A +e —— Since the difference of time between lunar high water and actual high water never exceeds about an hour and a half, if we neglect the separation of the moon from the sun in that time, this relationship also holds at actual luni-solar high water. Now, let —7 H cos (u—¢)=M+Scos [A+ Fin 8st hint 86] =M-+S cos (A—«,+38kn+Cokn), Hsin (p—9)= Ssin (A—«,+3$emtlomm) . . . . (19) and we have for the whole luni-solar semidiurnal tide fi COS C2 — OG) enon fede ). ot= ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. > = om In this way we find the corrections to the time of high water from O and / K,+P; and since n=y—s, and nay 0-988, and “~=1—-" for O, Arn n y—o and 14+ —°- for K,, we have ee éto=—0"-988 ( ee sin [14t—Z,—252° xn], Nat) YO, EE ; ét/ = —0h-988 (+ g ) RB sin [1St—0 41° xn], (25) y—o/ H where H is the height of the semidiurnal high water. With sufficient approximation we may write these corrections : ST RS = sin [14°t—Zo—252° xn], WoW < ie sin [1bt—Z/41exm] . . ss (26) The computations are easily carried out, although the arithmetic is necessarily tedious. Since two places of decimals are generally sufficient for R, and R’, the multiplications by the sines and cosines are very easily made with a Traverse Table. The successive high and low waters follow one another on the average at 6" 12"; now, 14° x 6-2=87°, and 15° x 6-2=93°. Hence, if we compute 14°t—¢,—254° xn for the first tide on any day, the remaining values are found with sufficient approximation by adding once, twice, thrice 87° ; and similarly, in the case of 15°t—Z’+1xn we add once, twice, thrice 93°. § 6. Certain Details in the Computation of the Tide-table. Tt will be well to give some explanatory details concerning the manner of carrying out the computations. The angle A is given by 16°51+43°'44 cos 8 — 0°19 cos 22, where ® is the longitude of the moon’s node. It is clear that A varies so slowly _ that it may be regarded as constant for many months, and the same is _ true of the factors f, f’, f, f,, and the small angles v, &, »/, 2y’, ‘Approximate formule for these quantities in terms of 3 were given in the Report of 1885, and are used in the article in the ‘ Manna.’ __ To find the cube of the ratio of the sun’s parallax to his mean parallax, the following rule is given : Subtract the mean parallax from the parallax, multiply the difference by 193, read as degrees instead of seconds, look out the sine,andadd1. This rule is founded on the fact that a mean _ parallax 8’"85 multiplied by 193 gives 3x 57’, and 57° is the unit angle or radian, whilst the sine of a small angle is equal to the angle in radians. Similarly, the cube of the ratio of the moon’s parallax to her mean parallax is 1+3 sin [60(parx—mean parx) ]. ; That is to say, for the moon: Subtract the mean parallax from the paral- lax, read as degrees instead of minutes, look out the sine, multiply by 3, : E2 52 REPORT—1886. and add 1. This rule depends on the fact that the moon’s mean parallax in radians is ¢b- For the purpose of applying the corrections 0;R,, ¢:Ry,, 62km, 2, ‘yy, it is most convenient to compute auxiliary tables for each degree of declination of the moon and minute of her parallax, and then the actual corrections are easily applied by interpolation. These tables serve for the port as long as the longitude of the moon’s node is nearly constant, or with rougher approximation for all time. The declinational and parallactie corrections to high water depend on the moon’s declination and parallax at atime anterior to high water by ‘the age.’ Hence, in order to find these corrections we have to know the time of high water in round numbers. Hach high water follows a moon’s transit at the port approximately by the interval 7. The Greenwich time of the moon’s transit at the port is the G.M.T of moon’s transit at Greenwich, less 2 minutes for each hour of HK. longitude, less the EH. longitude in hours. Then, if we subtract from this ‘the age ’ and add the interval 7, we find the G.M.T’s at which we want the moon’s declination and parallax. Thus, at Port Blair) the G.M.T. at which;= ieee: of )’s) we want parx. and decl. } transit at Gr.) —long. corr. for transit (02) —KH. long. of port (6"*2)—age of tide (32"6) + mean interval (9"°6) =G.M.T of )’s tr. at Gr.—29"4. Thus at Greenwich, on Feb. Ist, 1885, the moon’s lower. transit was at 2", and hence, corresponding to the lower transit at Port Blair of Feb. 1, we require the moon’s parallax and declination at 21" Jan. 30, G.M.T. The parallax at the nearest Greenwich noon or midnight is sufficiently near the truth, and therefore we take the parallax at 0" Jan. 31, which is 60’-0, and the excess above the mean is 3/0, and 1+3 sin 3° is 1:157, which is the factor p’. Actually, however, we read off the correc- tion 6,R,, and the other corrections 6,R,,, dg%, dgy straight from the auxiliary tables. § 7. On Tide-tables Computed by the above Method. A great deal of arithmetical work was necessary in making trial of the rules devised above and in various modifications of them, and I must record my thanks to Mr. Allnutt, who has been indefatigable in working out tide-tables for various ports, and in comparing them with official tables. The whole of the results, to which I now refer, are due to him. The following table exhibits the amount of agreement between a com- puted table and one obtained by the tide-predicting instrument. It must be borne in mind that the instrument is rigorous in principle, and makes use of far more ample data than are supposed to be available in our computations. The columns headed ‘Indian tables’ are taken from the official Indian tide-tables. ‘The datum level, however, in those tables is 3:13 ft. below mean water mark, whereas ‘Indian spring low-water mark’ is 3°55 ft. below the mean. Thus, to convert the heights given in the Indian tables to our datum 0°42 ft. or 5 ins. have been added to all the heights in the official table. ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 53 TIDE-TABLE FOR PORT BLAIR, 1885. Calculated Indian tables Caled. {Indian tables Times Times Heights Heights h. m. he tana: rea ft. in. Feb.1,H.W. . : ll 3pm. 11 4pm. 74 fase Feb.2,L.W. . . 5 21am, 5 18 a.m. oo | -0 2 H.W. ‘ ‘ 11 26 am. 11 3lam. 6°6 6 5 L.W. 5 ‘ 5 28 p.m. 5 25 p.m. 0-4 0 0 EO ka gal ble 8) pan. 11 43 pm. 71 6 11 Feb. 3, L.W. 5 56 a.m 5 56 a.m. 0:2 OF H.W. 0 3pm 0 9pm. 64 6 3 LW. 6 4pm 6 5pm. O7 7 Feb. 4, H.W. 0 l4a.m 0 20 a.m. 67 6 6 L.W. 6 3lam 6 33 am. 0-5 0 5 H.W. 0 40 p.m 0 48 p.m. 61 6 0 L.W. 6 42 p.m 6 44 p.m. 1-2 1 0 Feb. 5, H.W. 0 48 a.m 0 56am. 61 5 11 | L.W. 7 5am 7 9am. 1:0 0 10 H.W. 118 pm 1 28 p.m. 57 57 LW. 7 20 p.m 7 25 p.m. 17 L% Feb. 6, H.W. 1 24am 1 33 a.m. 5° ag | L.W. 7 41am 7 45 a.m. 15 1 4 H.W. 2 lpm 2 10 p.m. 5:3 5 2 L.W. 8 6pm 8 12 p.m. 2-2 21 | Feb. 7, H.W. 2 4am 2 13 a.m. 4:9 4 9 L.W. 8 23 a.m 8 25 a.m. i:9 1 10 H.W. 2 63 p.m 2 57 p.m. 49 410 L.W. 9 Tp.m 9 8p.m. 2°7 2 6 Feb. 8, H.W: 2 58 a.m 3 8am. 4°4 4 3. LW. 9 20 a.m 9 24 a.m. 2°4 22 H.W. 4 10pm 4 14p.m. All, 4.7 L.W. 10 42 p.m 10 40 p.m. 3:0 2 4 Feb. 9, H.W. Z 2 4 29 a.m. 4 40 a.m. 3 10 L.W. ; : 10 46 a.m. 10 57 a.m. 2 6 H.W. : ; 5 47 p.m. 5 48 p.m. Ait a7. A tide-table was computed for Aden for a fortnight, and the results were found to be somewhat less satisfactory than those in the above table. It must be remarked, however, that the sum of the semi-ranges of the three diurnal. tides K,, O, P is 2°340 ft., and is actually greater than the sum of the semi-ranges of the tides M, and S,, which is 2°265 ft. Thus, at some parts of some lunations the semidiurnal tide is obliterated by the diurnal tide, and there is only one high water and one low water in the day. In this case it is obvious that the approximation, by which we determine semidiurnal high and low water and apply a correction for the diurnal tides, becomes inapplicable. In the greater part of our computed table the concordance is fairly good; but the tide-predicting 54 REPORT—1886. instrument shows that on each of the days, 7th and 8th February, 1885, there was only one high and low water, whereas our table, of course, gives a double tide as usual. Again, on the 9th February there is an error of 68 minutes in a high water. These discrepancies are to be expected, since the approximate method is here pushed beyond its due limits ; and for such a port as Aden special methods of numerical approximation would have to be devised. } In a table computed for Amherst the agreement is not quite so good as was to be hoped; the error in heights amounts in two cases in fifteen days to nearly a foot, and in two other cases to three-quarters of an hour in time. It may be remarked, however, that the tides are large at Amherst, having a spring range of 20 ft. and a neap range of 6 ft., that the diurnal tide is considerable, and that the sum of the semi-ranges of the over-tides M,, 8, (which we neglect entirely) amounts to 6 inches. It appears also that the tidal constants are somewhat abnormal, for ‘HY’ =HH, instead of H”=;.H,, and further H,=75H’ instead of H,=4H’, Under these circumstances it is perhaps not surprising that the dis- crepancies are as great as they are. Tables were also computed for Liverpool and West Hartlepool, but no correction was here applied for the diurnal tides. The results were compared with the Admiralty tide-tables for Liverpool and Sunderland, In the case of Liverpool there were four tides in a fortnight in which there was a discrepancy in the times amounting to 12 minutes, and four other tides in which there was a discrepancy of a foot, and one with a dis- crepancy of 1.ft.2 ins. It was obvious, however, that the agreement would have been better if the correction for the diurnal tides had been applied. The spring rise of tide at Liverpool is 26 ft. In the case of Sunderland there were in a fortnight two discrepancies of 15 m., two of 14 m., two of 13 m., two of 12 m., &c. in the times, and in the heights one discrepancy of 3 ins., and four of 2 ins., &c. The spring rise at West Hartlepool is 14 ft. These two tables are quite as satisfactory as could be expected con- - sidering the approximate nature of the methods employed. Finally, in order to test the methods both of reduction and of predic- tion, Mr. Allnutt took the harmonic constants derived from our analysis of a fortnight of hourly observation at Port Blair, from April 19 to May 2, 1880, and computed therefrom a tide-table for that same fortnight. He then, by interpolation in the observed hourly heights, determined the actual high waters and low waters during that period. The results of the comparison are exhibited in the table on next page. If our method had been perfect, of course, the errors should be every- where zero. It must be admitted that the agreement is less perfect than might have been hoped. If, however, the calculated and observed tide curves are plotted down graphically side by side, it will be seen that the errors are inconsiderable fractions of the whole intervals of time and heights under consideration. When we consider the extreme complication of tidal phenomena, together with meteorological perturbation, it is, perhaps, not reasonable to expect any better results from an admittedly approximate method, adapted for all ports, and making use of a very limited number of tidal constants. In devising these rules for reduction and prediction I could find no model to work from, and it seems probable that advantageous 55 ON THE HARMONIC ANALYSIS OF TIDAL OBSERVATIONS. 0g-— ots G68 93-— F626 | 02-83 1¥-— GL:G 82-8 03-— 09-01 | 08-0T |° @ ue Lp. 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OLF af fa oul Gaia oan WHLY AA HOTEL LLG PB-LT 18-6 09 ST 9F-3 LUFT ¥9-T 98-81 0L-0 98-31 86-83 99.11 03-84 08-0T 18-26 66-6 91-18 08-6 90:12 19-8 1¥-08 08-2 89-61 91-2 10-61 03-9 63-81 9L-F " owtry, pearesqQ “ALITVOLOY HLIM NOILVAUESAO §,LHOINTYOT V WOU GALACNOD ATAVI-AdIT, V JO NOSIdvdWOD * 6. Indy 088T aqeqg ‘sv 56 REPORT— 1886. modifications may be introduced. I spared, however, no pains to reduce the labour of computation. Nearly half the work in forming a short tide-table is preparatory, and would serve for a systematic computation of tables for all time. Til. An Arrempet to Detect tor 19-Yearzty TIpe. If M, E be the moon’s and earth’s masses ; a the earth’s mean radius ; c the moon’s mean distance ; w the obliquity of the ecliptic ; 7 the inclina- tion of the lunar orbit; e the eccentricity of the lunar orbit; & the longitude of the moon’s node; and A the latitude of the port of observa- tion; then the term in the equilibrium tidal theory which is independent of the moon’s longitude (see Schedule B, iii., Report of 1883) is DELON Sh fae Jas aay EMER Sr ae = — (~) a (g—3 sin? A) (1+ $7) sin 7 cos 7 sin w cos w Bae [ —cos& +3 tani tan w cos 2 & j. Since 1 tan i tan w='00975, the second term is negligeable compared with the first. If we take M_ 1 a_ 1 591x108 feet, i? 8', «= 23° 28", the expression for this tide is, in British feet, —0:0579 (4—$ sin? A) cos &. Thus, at the poles this tide gives an oscillation of sea-level of 0°695 of an inch, or a total range of 12 of an inch, and at the equator it is half as great. ~ “In the ‘ Mécanique Céleste’ Laplace argues that all the tides of long period (such as the fortnightly tide) must conform nearly to the equili- brium law. I shall adduce arguments elsewhere ' which seem to invalidate his conclusion, and to show that in these tides inertia still plays the principal part, so that the oscillations must take place nearly as though the sea were a frictionless fluid. With a tide, however, of as long a period as nineteen years Laplace’s argument must hold good, and hence the equilibrium tide of which the above is the expression must represent an actual oscillation of sea-level, provided that the earth is absolutely rigid. The actual observation of the 19-yearly tide would therefore be a result of the greatest interest for determining the elasticity of the earth’s mass. A reduction of the observed tides of long period at a number of ports was carried out in Thomson and Tait’s ‘ Natural Philosophy,’ Part IL., 1883, in the belief in the soundness of Laplace’s argument with regard to those tides, and the conclusion was drawn that the earth must have an effective rigidity about as great as that of steel. The failure of Laplace’s argument, however, condemns this conclusion, and precludes us from making any numerical conclusions with regard to the rigidity of the earth’s mass, excepting by means of the 19-yearly tide. The results 1 In an article on the Tides in the Hncyclopedia Britannica. The section of the article ‘On the Tides of Long Period’ will probably be communicated also to the Royal Society. BP) SIS OF TIDAL OBSERVATIONS. ON THE HARMONIC ANALY *\[OUT TB JO ¢ 10 “a7 cQ.0 “Bos JO [dep Ut ‘ATTVOTAAA Puy ‘sTEQUOUT g ‘ommTy ut ‘A][e} MOzLIOY syMesotder oreNbs yOwS Jo opts oy, “Avo Towa Toy pagvntvade syydap Uvstt oy arv dAIMO OY4 UO staqtUNT dy} PUB ‘a8nvs-apyy oy} JO OLoz ot} OAOGB 4y L [dat SOUIS JO PATNO OY} JO sozVNIpAO OUT, jo Ja AQT OY} ST OUTIL poop oT *TOVAVY, JV ToywWM Wee JO SsuOT}e TIVA OY} S}tasetd 9AM snonuls aL J, C oO 800 "97 S z 0— quasa 58 REPORT—1886. given in the ‘ Natural Philosophy ’ merely remain, then, as generally con- firmatory of Thomson’s conclusion as to the great effective rigidity of the earth’s mass. There are but few ports for which a sufficient mass of accurate tidal observations are accumulated to make the detection of the 19-yearly tide a possibility. Major Baird has, however, kindly supplied me with the values of the mean sea-level at Karachi for fifteen years. They are plotted out in the annexed figure. The horizontal line represents the mean sea-level for the period from 1869-1883, and the sinuous curve gives the variations of mean sea-level during that period. The dotted sinuous curve gives the annual variations for a portion of the same period for Bombay. The full- line sweeping curve has ordinates proportional to —cos &, and shows the kind of curve which we ought to find if the alternations of sea-level were due to the 19-yearly tide. It is obvious at a glance that the oscillations of sea-level are not due to astronomical causes. At Karachi (lat. 24°47’) the 19-yearly tide is —0*-0138 cos &. The figure shows that the actual change of sea-level between 1870 and 1873 was nearly 0:25 feet, and this is just about nine times the range of the 19-yearly tide, viz., 0-028 feet. It is thus obvious that this tide must be entirely masked by changes of sea-level arising from meteorological causes. It seems unlikely that what is true of Karachi and Bombay is untrue at other ports, and therefore we must regard it as extremely improbable that the 19-yearly tide will ever be detected. G... 83 Report of the Committee, consisting of Professor Crum Brown (Secretary), Mr. Minyz Home, Mr. Jonn Murray, and Mr. Bucuan, appointed for the purpose of co-operating with the Scottish Meteorological Society in making Meteorological Obser- vations on Ben Nevis. Durinc the past year the work of the Ben Nevis Observatory has been carried on by Mr. Omond and his assistants in a way that leaves nothing to be desired. The twenty-four daily eye-observations have been made uninterruptedly ; and it deserves to be recorded that, as regards the out- side observations, no hour has been omitted even on those occasions when the wind blew furiously at rates considerably above 100 miles an hour. The eye-observations, taken five times daily at the sea-level station at Fort William, have also been made with the greatest regularity by Mr. Livingston ; and with these are conjoined the continuous records of the barograph and thermograph, the results of which are so valuable in checking and discussing the observations. For the twelve months ending May 1886 the mean temperatures and pressures at the Ben Nevis Observatory and Fort William were these :— : : | - ON METEOROLOGICAL OBSERVATIONS ON BEN NEVIS. 59 Observatory | Fort William | ———E—EE Temp. | Pressure, Temp. | Pressure, é Inches 5 Inches — Summer. . 39°3 257502 | Summer . 55°5 30°027 Autumn . ...| 29:9 185 | Autumn. . .| 45:2 29'736 Winter . . .| 225 244 || Winter . . .| 368 880 Spring . . .| 264 2760/0? Spring? Cie ga TaSit 873 ean |) 2 i) 029:6 25-302) no |\) Wear iste). (11 453 29 879 These twelve months were thus characterised by an unusually low mean temperature, the annual mean at the sea-level station, 45°3°, being 1-9° below its normal mean temperature. The maximum temperature at the observatory for the period was 60:0° . at 3 p.m. of July 31, which nearly approaches the mawinwm of previous years, viz. 60°1° at 2 p.m. on August 9, 1884. The lowest temperature was 8:4° at noon, December 29, 1885, which is the lowest temperature yet recorded on Ben Nevis. The lowest temperatures for the three winters have been respectively 9°9°, 11:1°, and 84°. But the most remarkable features in the climate of Ben Nevis during the year were the frequent occurrence of excessive droughts, compara- tively large amount of sunshine, and occasional unusually heavy falls of rain and snow. The following observations were made on July 30, 1885 :— Dry Wet Diff. ° ° ° TSAR. sg A 48°8 46°9 9 oT 5 5 . 48°3 45°3 3-0 Dyt a : 3 50°3 36:2 14:1 4i+ - P 49°7 36:2 13°5 _ Such low humidities, sharply marked off from high humidities, are among the most valuable observations of the observatory, particularly when viewed in connection with the irregular geographical distribution of frosts and other low night temperatures which occur over the country on subsequent evenings, But the most remarkable drought yet recorded at the observatory occurred in March last, commencing at 1 a.m. of the 11th, and ending at midnight of the 12th, thus extending over a period of forty-eight hours. The mean humidity of the first twenty-four hours was only 19, and of the second twenty-four hours 15, the lowest being 6 at 8 p.m. of the 12th. From noon of the i2th to 11 p.m. the mean was only 11. The three consecutive hours of greatest dryness were the following :— é Dry Wet Dewpoint Huwidige March 12,1886,7P.M. . . 21°8 148 32-1 7 I Seino eFlin eye! 21-0 140 343 6 y ame rieds wii 19°2 13-0 32-3 8 During these two days the sky was absolutely cloudless, and the wind south-easterly, blowing at first with force 5, then falling gradually to 3 60 REPORT-—1886. at 9 a.m. of the 11th, about which it remained till 4 p.m. of the 12th, when it fell either to a calm or the lightest airs from the north-east, when the greatest dryness took place. On these two days the extremes of tem- perature were 24°3° and 13°3°; and at 8 a.m. of the 12th, while the tempe- rature at the observatory was 23°9°, in Fort William it was 19°2°, or 47° lower than on the top of Ben Nevis. During the twelve months the Sunshine Recorder registered 777 hours of sunshine, which is about 19 per cent. of the possible sunshine. In the previous year the hours of sunshine only amounted to 464. The extreme months were July, with 162 hours, and January, with only 15 hours of sunshine. The observations of the two years show that the annual period of daily maaimum sunshine is the four hours from 9 A.M. to 1 P.m., the means being 61, 67, 67, and 65 hours respectively. For the six months from April to September the hour of most sunshine is from 8 to 9 a.m., _ the mean being 39 hours. From this time it slowly but steadily diminishes to 36 hours for the hour ending 1 p.M., and from 4 to 5 p.m. the number has fallen to 26 hours. The numbers for the five hours preceding, and the five hours succeeding noon, are respectively 88 and 32 hours. The total number of hours for the six months, from January to June, is 294, and for the second half of the year 326 hours, the difference being wholly due to the exceptionally large amount of sunshine in July and August 1885. In truth the distribution of the sunshine through the year cannot be said to be dependent on the great annual rise and fall of temperature, but on those causes which bring anticyclones over Ben Nevis. The rainfall for the year ending May 1886 amounted to 128:34 inches, the largest monthly fall being 24°33 inches in December 1885 and the smallest 2°85 inches in February following. The heaviest precipita- tion on any day was 5°34 inches on December 12, and 4°45 inches on January 1—these being heavier than any previously recorded daily falls. On the two days December 12 and 13 the precipitation amounted to 8°86 inches. For five-day periods the following heavy falls are recorded :— for the five days ending December 15, 10:25 inches; October 5, 10-02 inches; January 3, 9°25 inches; and September 16, 6°13 inches. On the other hand, the year was marked by the large number of days on which either no rain fell or on which the amount was less than 0-01 inch. The number of these days amounted to 126, being thus in the proportion of two rainy days for each fair day. The largest number of fair days in any month was twenty in August, and the least, two, in Sep- tember. In the previous year there were only seventy-nine days without rain, being thus forty-seven fewer than last year. In the meantime, the whole of the hourly observations of the observa- tory, and the observations of the station at Fort William down to date are in the press. The publication will appear as an extra volume of the ‘ Transactions of the Royal Society of Edinburgh,’ and by this handsome act on the part of the Royal Society these observations will shortly be in the hands of scientific men in all parts of the world. In connection with the Ben Nevis observations the investigation of the important question of the bearing of the results on the weather of these islands steadily advances. The position of the observatory on an elevated isolated peak, and that of the low-level station at Fort William, being close to the sea and on a hank sloping down to it, renders this pair of stations second to none anywhere yet established for the investigation of some of the fundamental data of meteorology. Among the more im- ON METEOROLOGICAL OBSERVATIONS ON BEN NEVIS. 61 portant of these is the rate of decrease of temperature with height, and the rate of diminution of pressure with height, for different atmospheric temperatures and sea-level pressures. In these aspects the double set of observations for the past two-and-a- half years have now been discussed. The decrease of the temperature with height is at the rate of one degree Fahrenheit for every 270 feet of ascent, the lowest rate being one degree for every 284 feet in winter, and the most rapid rate 247 in spring. _ This rate closely agrees with the results of the most carefully conducted balloon ascents, and of those other pairs of stations over the world which are so situated as to give trustworthy results for the inquiry. Ben Nevis Observatory and Fort William Station are among the very few pairs of stations yet established from which the requisite data can be obtained, the required conditions being great difference in height combined with close proximity, and the position of the thermometers in situations where the effects of solar and terrestrial radiation are minimised. The next point, and as regards weather phenomena the most -important point, to be determined was the normal differences between _ atmospheric pressure at the top of the Ben and at Fort William for the different air temperatures and sea-level pressures that occur. These _ differences, or, as they are technically called, corrections for height, were : i .. empirically calculated from the observations, and thereafter the departures from these normals were ascertained for each of the five daily observations since the observatory was opened. The results showed a diminution of pressure from the normals on almost every occasion during the occurrence of high winds at the observatory. In other words, in all cases when high winds (30 miles an hour and upwards) prevailed at the observatory the observations reduced to sea-level showed a less pressure than that actually observed at Fort William. The differences increase with the strength of the wind, and amount not unfrequently to the tenth of an inch, and one day when the winds continued to blow at the rate of 120 miles an hour, the five consecutive readings showed differences exceeding a tenth and a half. This diminution is doubtless occasioned by the winds as they brush past the buildings, partially sucking out the air from the interior, thus lowering the pressure. It was therefore necessary to recalculate the table of corrections to sea-level, using in the new calcula- tion only those observations which were made when the wind blew at lower rates than 30 miles an hour. This recalculation has been recently completed, and the inquiry as to the bearing of the Ben Nevis observa- tions on the weather is being pushed forward. So far as the investigation has been carried, it is evident that rapid and considerable changes from the normals, but particularly a more rapid decrease of temperature with height than the normal decrease, as shown by the thermometric observations, are frequently a precursor and concomi- tant of storms of wind. This is only what might be expected considering that such observations indicate a disturbance of the equilibrium of the atmosphere. But when with this is conjoined a lower sea-level pressure, as calculated from the Ben Nevis Observatory barometric readings, than what is actually observed at Fort William ; in other words, when the barometric observations indicate a more rapid decrease of temperature with height somewhere in the aérial stratum between sea-level and the top of the Ben than the thermometric observations alone indicate, then the indications of a coming storm become more decided. Conversely the absence of any 62 REPORT—1886. abnormally rapid decrease of temperature with height as revealed by all ‘the observations is seldom followed by storms of wind. For a number of years past the Scottish Meteorological Society has, | through the courtesy of the Commissioners of the Northern Lighthouses, been favoured with meteorological observations from all the light- houses, the keepers being regular observers of the Society; and an important part of their duty as such is to record the hour of beginning and ending of all strong winds, gales, and storms which occur. The observations, made since the establishing of the observatory in December 1883, have been plotted on monthly sheets, which show graphically when storms have occurred at the lighthouses; and on the same sheets have been entered for the respective districts all cases when storm-signals have been hoisted under direction of the Meteorological Office. This investiga- tion is still in progress, but the following results may be provisionally stated. Leaving out of view those cases in which the barometer at the observatory was lowered by high winds, as above explained, by far the larger number of the remaining cases, when the calculated sea-level pressure was less than what was actually observed at Fort William, preceded or accompanied storms, and when the differences were unusually great the storms were severe and widespread. Again, neglecting the occasions during 1884 when the wind at the observatory exceeded 30 miles an hour, there remain nine instances which in the west and north of Scotland were not followed by a storm. On eight of these occasions the observations did not indicate the existence of a disturbance in the lower stratum of the atmosphere between Fort William and the observatory. The Ben Nevis Observatory may be regarded as contributing, towards the forecasting of the weather of the British Islands, a body of facts differ- ing wholly in kind from what is contributed by any other meteorological observatory or station in the country. To the bearing of these observa- tions on weather the directors propose to direct attention next year; and thereafter to use the results that may be arrived at in an examination of the observations of the high-level stations of Hurope in their relations to the paths pursued by storms over the Continent. Mr. Omond, superintendent of the observatory, has compared the results obtained from the registrations of Professor Chrystal’s anemometer with the estimations of wind-force made by him and the assistants on scale 0 to 12, and thereby determined the velocity in miles per hour for each figure of the scale 1, 2, 3, &c. The highest figure for which the double observations were sufficiently numerous, so as to give a good average, was 8, which was found to be equivalent to a rate of 73 miles an hour. This wind-force is of frequent occurrence, and as regards the higher estimations Mr. Omond estimates force 11, which occasionally occurs, as equivalent to a rate of 120 miles an hour. This paper has been published by the Royal Society of Edinburgh. Mr. Omond has written another paper on the rainfall of Ben Nevis in 1885 in relation to the winds. The investigation shows that, as regards the rainfall, the winds arranged in their order of greatest frequency are N., 8.W., W., S.E., S., N.E., N.W.,and E., the N.W. and E. winds being remarkably few in number. As regards the total fall the order of the winds for wetness is W., N.W., 8.W.,N., S., N.E., S.H., and E. Thus the direction of wind with which most rain came during 1885 was a little ON METEOROLOGICAL OBSERVATIONS ON BEN NEVIS. 63 north of west, and the quantity diminishes as we go round the compass in both directions, until the driest point is reached a little south of east, _ the east again having a very low value. The dryness of S.E. winds is remarkable. They seem mostly to occur when an area of high pressure is moving off and a cyclonic storm approaches from the west; and this dry character indicates that the wind shifts when the ‘storm actually reaches the observatory and the rain begins to fall. For the past two years much attention has been given by Mr. A. Rankin, the first assistant, in making rainband observations, and he has discussed them in an interesting paper, recently read before the Scottish - Meteorological Society, which, along with Mr. Omond’s paper on the Rainfall and Winds, will shortly appear in the Society’s journal. A series of elaborate hygrometric observations was made at the obser- vatory during August, September, and October 1885 by Mr. H. N. Dickson, under the direction of Professor Tait and Mr. Buchan. The _ observations have been discussed by Mr. Dickson in a paper recently read before the Royal Society of Edinburgh. The results are of consider- able value in determining how far Glaisher’s factors, so largely used by meteorologists in hygrometric inquiries, can be safely used. As regards the remarkably dry states of the air, which form so prominent a feature in the climate of Ben Nevis, Glaisher’s factors are found to be altoge- ther inapplicable, and the hygrometric observations will therefore require a specially constructed set of tables. Copies of this and the other papers referred to above will, when published, be forwarded to the Association. Third Report of the Committee, consisting of Professor Batrour Stewart (Secretary), Professor Stoxrs, Professor ScHUSTER, Mr. G. Jounstone Stoney, Professor Sir H. E. Roscoz, Captain Asyry, and Mr. G. J. Symons, appointed for the purpose of considering the best methods. of recording the direct Intensity of Solar Radiation. THe Committee, in conformity with their last report, have had con- structed by Mr. Casella an instrument of the following description :— It consists of a cubic copper enclosure, 35 inches square outside, the faces of which are 3 of an inch thick. This cube is packed round with felt, 3°; of an inch thick, and the whole is faced outside with thin polished brass plates, ;', of an inch in thickness. In that vertical face of the cube which is intended to face the sun two holes are bored into the copper from above. These holes are equally - distant from the centre on each side, and are intended to receive the cylin- drical bulbs of two delicate thermometers wrapped round with tin foil so as to be in metallic contact with the copper. Let us call these thermo- meters A and B. In the opposite face of the cube there is one such hole bored centrally into the copper, also intended to receive the bulb of a thermometer, which we shall call C. Finally, in the very centre of the enclosure there is placed the bulb of a thermometer similar to the above, which we shall call D. This last thermometer occupies the position that will ultimately be occu- pied by the interior flat bulb thermometer upon which the sun is to play 64 REPORT—1886. through a hole, as mentioned in our last report, only this hole has not yet been constructed. The thermometers A, B, C, and D have been carefully verified at the Kew Observatory. It is proposed to place these thermometers in their respective holes, to expose the instrument to the sun as it will be ultimately exposed, and then to read the thermometers from time to time. If it shall be found that the central thermometer D has a temperature which bears a nearly con- stant relation to the temperatures of the front face as represented by A and B, and of the back face as represented by C, the Committee will proceed finally with the construction of the instrument. If, however, the temperature of D be not related to those of the other thermometers in a sufficiently definite manner, the Committee may require to reconsider the construction of the instrument. The Committee have expended 9/1, 10s. 6d. and returned to the Asso- ciation a balance of 101. 9s. 6d. They suggest that they be reappointed, and that the sum of 20/. be again placed at their disposal. Second Report of the Committee, consisting of Professor BaLrour Stewart (Secretary), Professor W. G. Apams, Mr. W. Lant CaRPENTER, Mr. C. H. Carpmart, Mr. W. H. M. Caristiz (Astronomer Royal), Professor G. CurysTaL, Staff Commander Creak, Professor G. H. Darwin, Mr. Witt1am EL ts, Sir J. H. Lerroy, Professor S. J. Perry, Professor Scuuster, Sir W. Tuomson, and Mr. G. M. Wurreie, appointed for the purpose of considering the best means of Comparing and Reducing Mag- netic Observations. Drawn up by Professor BaLrour Stewart. [Puatss I., II, and IIT.] Ir is with deep regret that the Committee record the death of one of their number—Captain Sir Frederick Evans, so well known for the valu- able contributions which he has made to terrestrial magnetism. His eminent scientific qualities combined to make him a greatly esteemed member of this Committee, who now deplore his loss. The Committee have added to their number the following gentle- men: The Astronomer Royal, Mr. William Ellis, Professor W. G. Adams, and Mr. W. Lant Carpenter. They could hardly consider their list com- plete without the addition of the first two names, and they are glad that, although not members of the British Association, these gentlemen were not unwilling to serve on one of its committees. Since the last meeting of the Association Mr. G. M. Whipple has made a comparison between the method of obtaining the solar-diurnal variation of declination adopted by Sir E. Sabine, and that of Mr. Wild. These methods were applied to three years’ observations at the Kew Observatory, and the results were compared with those deduced by the Astronomer Royal from the same three years at Greenwich. The comparison will be found in Appendix IV. to this report. The Committee think that this comparison deserves careful study, but they do not feel themselves able to pronounce as yet upon the com- ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 65 parative merits of these various methods. Nevertheless, they are of opinion that it is highly desirable to record the daily mean values (un- disturbed) of the three magnetic elements side by side with their solar- diurnal variations. It will be seen by Appendix III. that Sir J. Henry Lefroy has con- tinued his comparison of the Toronto and Greenwich observations. He has obtained from the smooth curves—that is to say, taking Mr. Wild’s method—results which appear to him to show that the turning-point of the declination is decidedly later in local time at Toronto than at Greenwich. Sir J. H. Lefroy attributes this to the fact that these two stations are on different sides of the Atlantic.} Appendix II. exhibits, by aid of a diagram, an interesting comparison of Senhor Capello between the diurnal variation of the inclination and that of the tension of aqueous vapour. It is remarkable to notice the great similarity between these variations ; a similarity which holds sepa- rately for each month of the year. Senhor Capello hopes that these results may be confirmed by a more extended series of observations. The researches to which allusion has now been made refer to the solar-diurnal variation, excluding disturbed observations. With respect to disturbances Sir J. Henry Lefroy has continued his comparison of Toronto and Greenwich, and his results are indicated in Appendix III. Professor W. G. Adams has, it is well known, made extensive com- parisons between the simultaneous traces of magnetographs in various places. He is at present engaged on such an undertaking, and the Committee are in hopes that when this is completed he will give them the benefit of his experience. Captain Creak and other members of the Committee feel disposed to consider the continuous observation of earth currents an important part of magnetic work. The Rev. S.J. Perry and Professor Stewart (Appendix V.) have com- pleted their preliminary comparison of certain simultaneous fluctuations of the declination at Kew and at Stonyhurst in a paper which has been published in the Proceedings of the Royal Society, No. 241, 1885. The results are virtually those which were stated in the last report of the Committee. The comparison is being continued and extended. Professor Stewart and Mr. W. Lant Carpenter (Appendix VI.) have given the results of other four years’ reduction of Kew declination dis- turbances classified according to the age of the moon. These are very similar to the results of the first four years given in our last report. The same observers give a comparison, extending over four years, between declination disturbances and wind values, which appears to them to show that there is some relation between these two phenomena. They are anxious to continue and extend both these inquiries. Professor Stewart has pointed out certain general considerations which appear to him to indicate that the solar-diurnal variation may per. haps be caused by- electric currents in the upper atmospheric regions. Dr. Schuster has likewise made a preliminary application of the Gaussian analysis, tending, in his opinion, to confirm the hypothesis that currents in the upper regions are the cause of these variations.” By this analysis Dr. Schuster obtains certain relations between the * See Appendix by Sir G. B. Airy to the Greenwich Observations, 1884. * An account of these researches will be found in the Phil. Mag., April and May 1886. 1886. FP 66 REPORT—1 886. solar-diurnal variations of the three magnetic elements which ought, in his opinion, to hold on the hypothesis that these variations are caused by cur- rents in the upper atmospheric regions. One of these is that the horizontal force component of the daily variation ought to have a maximum or mini- mum at the time when the declination component vanishes—that is to say, attains its mean position. Another is that the horizontal force ought to be a maximum in the morning and a minimum 4%n the afternoon in the equatorial regions, while in latitudes above 45° the minimum ought to take place in the morning. A third is that in the equatorial regions the maximum of horizontal force ought to be coincident with the minimum of vertical force, and vice versd. These conclusions are considered by Dr. Schuster to be sufficiently well confirmed by observations, and thus to render hopeful the first attempt to apply the Gaussian analysis to the solar-diurnal variation. The appendices of Captain Creak (I.) and of Dr. Schuster (VII.) have reference to this subject, and maintain the importance of some action being taken by the Committee to prepare for a thorough application of the Gaussian analysis to the magnetic variations. It will be seen from the remarks of Dr. Schuster that some time must elapse before observations are obtained sufficiently good and complete to justify a systematic appli- cation to them of mathematical analysis. This circumstance has induced the Secretary to lay before this Committee in Appendix VIII. a pro- visional working hypothesis regarding the cause of the periodic variations of terrestrial magnetism which has gradually grown up by contributions from various quarters. While this Committee do not hold themselves responsible for the various statements contained in this hypothesis, they would point out the desirability of ascertaining to what extent well-known magneto-electric laws may succeed in accounting for the phenomena of terrestrial magnet- ism, and likewise the desirability of ascertaining to what extent the magnetic earth appears to be subject to the laws of ordinary magnets. A preliminary working hypothesis of this nature might serve to elicit facts while the material for the Gaussian analysis is being completed, and it would add to the interest of the final result if we should obtain reason to think that electric currents in the upper atmospheric regions are at once the ‘nzinediate causes of magnetic variations and the effects of atmo- spheric motions in these regions, so that a knowledge of the one set of currents might possibly enable us to determine the other. In Appendix IX. we have a practical example by Mr. C. Chambers of the method of reduction which he suggested in Appendix XII. of the last report of this Committee. Finally, in Appendix X. there are some remarks by Captain Creak on the advantages to the science of terrestrial magnet- ism to be obtained from an expedition to the region within the Antarctic Circle. The Committee have drawn 10]. 10s., and returned to the Association a balance of 297. 10s. They would desire their reappointment, and would request that the sum of 50/. should be placed at their disposal, to be spent as they may think best on the researches mentioned in this report. a le sn nati atten nal ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 67 , APPENDIX. I. Letter from Captain Creak to Professor Stewart. Richmond Lodge, Kidbrooke Park Road, Blackheath: April 26, 1886. Dear Professor Stewart,—In the appendix accompanying the last Report of the Committee on Reducing and Comparing Magnetic Obser- vations, so many valuable suggestions are made by various well-known magneticians that I feel there is little left for me to add. I have long noticed the difficulties attending Sabine’s method of separating the disturbances from the normal yalues of the solar diurnal variation of the declination. It has done good work in the past, but now the question has arisen, Has a better been proposed? I think that adopted at the Greenwich Royal Observatory is better, and that the whole of the Greenwich methods of reduction, as set forth in the pub- lished volume of ‘Magnetic Reductions’ of 1883, invite the attentive consideration of the Committee, with a view to their adoption as a whole or in part. TI am, however, disposed to think that the method proposed by M. H. Wild, of ascertaining ‘the normal daily path of the magnetic elements,’ has much to commend it, and is rather less open to the possibility of individual bias than that of Greenwich. In recalling to the notice of the Committee Gauss’s valuable memoir ‘On the General Theory of Magnetism,’ I consider Dr. Schuster has done excellent service. Possibly the prospect of formidable computations has prevented Gauss’s treatment of magnetic observations from being hitherto adopted, but if, as Dr. Schuster proposes, by selecting stations the com- putations may be reduced within comparatively easy limits, I would suggest some such course as follows :— (1) That the selected stations be fixed observatories provided with the usual magnetographs of like pattern. (2) That the several Superintendents be invited to make a series of observations for a year or more of the solar diurnal variation of the three magnetic elements, according to a method to be decided by the Com- mittee, with a view to their being treated after the method of Gauss. (3) That Earth currents be made, as far as possible, a subject of observation at each observatory. In thus advocating the application of Gauss’s method of calculation to the variations of the magnetic elements, I apprehend that the most im- portant immediate result will be the settlement of the question whether the causes are situated above or below the surface of the Earth, and consequently we shall thereafter be better instructed as to the path we should follow in future observations. Although in these suggestions only future observations have been _ considered, it is not in forgetfulness of the large and valuable series _ already obtained, which all must wish to see made generally available by being rendered in a common form. I remain, yours truly, Errrick W. Crna. II. Letter from Senhor Capello, Lisbon, to Professor Stewart. Lately in studying the diurnal variation of the tension of vapour at Lisbon, I have been struck with the great similarity of the course of this F2 68 REPORT—1886. meteorological element, and that of the magnetic inclination, as shown in the following curves. It will be very difficult to say what direct connection there can be between the tension of vapour and the magnetic inclination, but the great similarity of the curves (month by month), and also in the different ARIA TION-|OF,VAFOURTENSION: 1864—1880, SE 775 hol OS a ra : AEE C qt Ol : basseien AC ; 7 So eae as 7 Gann : BKES lA Z NCI { NN seasons (although the phases of the inclination are nearly two hours earlier) make one think that at least the causes of the variations of these heterogeneous elements are the same. One would therefore attribute to the currents of the atmosphere the magnetic variations: can it be that the vertical currents which are sup- ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS, 69 posed to be the cause of the variations of the tension of vapour can also produce the movements of the inclination needle ? It will be necessary to carefully verify this connection for different places. I send you the diurnal curves for these two elements. L IATION_\OE| INCLINATION. DIURNA VARIATLON Ef 7 NA KM NC VV TN Il. Hatract of letter from Sir J. Henry Lefroy to Professor Stewart. I have virtually finished the comparison of Photographic Records of Declination at Greenwich and Toronto for 1850, and have made up mean curves for each month from the undisturbed days alone, generally 7 or 8 in number (the total number for Greenwich is 99). On plotting the means they give, notwithstanding the small number of days in some of them, very regular curves are obtained, and they present a feature which is new to me. Sabine never compared Greenwich with his colonial stations, and has not, that I remember, remarked it. It is that the N. end of the magnet reaches the most westerly position of the 24 hours from 1 to 15 hour earlier at Greenwich than it does at Toronto. This appears in every month compared ; there are only seven of them, as the whole apparatus caught fire and was destroyed in June, and did not get to work again before November ; but seven months are good for something. The detailed comparison of disturbed movements has not suggested much beyond the fact that there is rarely any marked correspondence, and that the movements are usually in contrary directions. I have transferred all the Greenwich movements of any magnitude to my sheets, and this is 70 REPORT—1886. apparent too frequently to leave any doubt that it is the law ; it could only be demonstrated by lithographing examples. I enclose a tracing of mean curves from the tracings of undisturbed days, together with an abstract _ ofthe numerical values. The Greenwich turning points agree very closely with those at Dublin. That they are so much earlier than they are at To- ronto seems to me likely to be traceable to some influence of the Atlantic on the mean direction of the currents. I should add to my explanation that, to obtain three months for the winter solstice, January from the beginning of the year was grouped with November and December at the end, as I had not the next following month of January. Senhor Capello has sent me his curves showing the general corre- spondence of character between the diurnal changes of magnetic inclina- tion and those of the tension of vapour in the atmosphere. Lloyd in 1849! showed that the area of the diurnal curves of declination gave an annual progression closely resembling the corresponding progression given by the area of the daily curves of temperature, with which the tension of vapour is so intimately connected ; so that it would seem that there is a closer connection between meteorologic and magnetic pheno- mena than has been supposed. Abstract of mean Solar-diurnal Curves of Declination by measurement from photo- graphic records at Greenwich and Toronto, 1850. Undistwrbed days only, grouped in astronomical seasons. Wote.—The mean date of each group only corresponds approximately to the equinox or solstice, the days being irregularly distributed. —=Eofmean. +=W of mean of the 24h. Greenwich. Toronto. MT z ; Summer Autumn Winter Vernal Winter b} E Ss E 5S 4 / i i ‘ Midnight —0°91 —1:3 —0 84 —O71 — 0°20 13 —1:43 —1:45 —0°63 —0O-76 —0°25 14 — 115 —1'54 — 0°23 — 0°82 + 0°04 15 — 1°64 —1°84 — 0°42 — 0°82 — 0:46 16 —2711 —1°65 — 0°55 — 1°41 —0°57 17 —3°68 — 2°54 —0°76 —1:19 —111 18 -- 4:50 —3'56 —0:96 — 2°35 —1:02 19 — 4°89 —4:53 —1:05 —4:22 —2:08 20 — 425 — 4°26 —1:02 —5:91 —3-08 21 —2:02 —1°68 —0°88 — 6°34 —4:13 22 +1°89 + 2°20 + 0°66 —411 — 2°85 23 +544 +5°75 + 2°58 —1-60 —0:47 Noon +710 +667 +3°34 + 2°05 +1:72 1 + 7:24 +679 + 2°99 +5°58 +3°05 2 + 5:93 +5'52 +213 + 6°23 +3°61 3 + 3°86 +3°31 +0°73 + 5°50 +3°55 4 + 1°85 +1:32 +048 + 4:20 + 2°94 5 + 0°28 — 0°39 —0:05 + 2°95 +2°22 6 — 1:05 —0°92 — 0°43 + 1:93 + 0°87 ff — 1:36 —1:07 —() 66 —1:05 -—001 8 —1°52 -1:15 —1-06 + 0°57 —0°44 9 —1:17 —1:13 —1-20 +018 —0-60 10 —1:26 —1-02 —1°41 — 0:08 —0°30 11 —0°95 —1:25 —114 —0°28 —0°53 The Greenwich observations were 20m. after the hours named; the Toronto observations 25m. before the hours named. ' Trans. R. Irish Academy, vol. xxii. Pt. I. ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. (a. The days accepted as undisturbed are the following :— Greenwich. Toronto. Jan. - . 14, 15, 16, 17, 21, 22. Jan. ¢ @ 04515 162 17 222: Feb. c ee oli Feo oli7 5, Dep, Feb. ; » 4610; 14, 17, 25.27, 28. Mar. . « 2 8,14; 18, 20, 28, 29. Mar. Bee 28 i416) 90098199. Apr. " . 3, 5, 16,17, 23, 25, 26, 30. Apr. C - 3, 9, 23, 26, 30. May 5 - 5, 6,10, 15, 21, 25, 30, 31. May ~ «! 5, 6, 10; 21, 22, 25, 29, 30, 31. June - 11, 12, 15, 20, 23, 24, 25, 29, 30. | June . ee: July 5 ee), 45.145 17; 26,01 | July : — Aug. C = G6, 7, 14, 25, 26,28. 31, Aug. 2 ° — Sept. : eile, Ube 7- 120, 2.26. Sept. , ‘ “= Oct. A », 4,10, 11,.21,.22) 24. Oct. F . —_— Noy. . 4, 6; 8, 15:17, 22/23, 24,.28. Novy. 0 ~ 16% 23! 27°28. Dec. - 8, 7, 9, 10, 13, 14,19, 20, 21, 30. | Dec. - Fin ta ye nc ep OF 0) 5 om Ee ss July 1, 1886. J. H. Lerroy. IV. Report by G. M. Whipple. In the Report of the Committee presented to last year’s meeting, Dr. Wild, of St. Petersburg, submitted a Table showing the different values of the solar-diurnal variation of the declination in Pawlowski for October 1882 and March 18853, as derived from the photographic records of ‘that observatory, after treatment by the two methods of Sabine and Wild. He found that the difference in the value of the declination at any hour of the day for the two months in question varied from +08 to —0°9 in a range of 8:1, or 21 per cent., of the whole. At the request of the Committee I have prepared tables showing the mean daily variation of declination at the Kew Observatory for the three years (1870-1872) and have contrasted the values obtained there, by Sabine’s and Wild’s methods, both for the whole year, as well as for the summer and winter semi-annual periods. I have, in addition, compared both sets of values with those published by the Royal Observatory, Greenwich, for the same periods. The results given in Table III. would show that the differences in the values of the diurnal range of the declination magnet at the Kew Obser- vatory, as determined by Sabine’s or Wild’s methods, vary to an extent of 0-7’ in a total range of 12’, or may equal 6 per cent. of the whole; whilst in the summer half-year (Table I.) the extreme difference amounts to 1-1 in a range of 15’, or 7 per cent., and in winter to an extreme difference of 0°8 in a range of 8:7, equal to 9 per cent. _ The greater diurnal range is afforded in every instance by Sabine’s method of treatment of the observations, although the difference is but small. Contrasting the Kew results with those of Greenwich, we may fairly consider the difference to be due in some measure to instrumental canses, the construction of the magnetographs being dissimilar at the two obser- vatories. The slight difference in position of the two observatories may likewise have some influence. Accordingly, Table III. shows that the normal daily range at Greenwich differs from that at Kew, as deduced by Sabine’s method, by 1-4’, or from that derived by Wild’s method by 1°8’, in a range of 11:6’, the percentages being 12 and 15 respectively. In the summer half-year (Table I.) we get differences of 1:4’, or 10 per cent., by Sabine’s, and the same percentage by Wild’s method, in a range of 14°7’; whilst in the winter we similarly obtain differences of 1:3! by Sabine’s, and 2°0/ by Wild’s method in a range of 8°4’, or percent- ages of 16 and 25 respectively. G. M. Wuiete. KEW OBSERVATORY, July 1886. : Owing to imperfections of the record only these two days were eventually used. * Apparatus destroyed by fire. : 3 Record begins Nov. 12. 72 1870. SUMMER. April Greenwich . to { Kew (1) . September (Kew (2). WINTER. Jan, to Mar. if Greenwich . and Kew (1) . Oct. to Dec. ker (2). 1871. SUMMER. April Greenwich . to Kew (1). September (Kew (2). WINTER. Jan. to Mar. (Greenwich . and Kew (1) . Oct, to Dec. Kew (2). 1872. SUMMER. April Greenwich . to Kew (1) . September (Kew (2). WINTER. Jan. to Mar. (Greenwich . and Kew (1) . Oct. to Dec. ( Kew (2) . SUMMER. Greenwich . Kew (1) . September Kew (2) . WINTER. ( Greenwich . Jan. to Mar. and Oct. to Dec. Kew (1). . |rew (2) Differences of 3 years’ Semi- annual Means ... . Differences of 3 years’ Semi- annual Means ss Differences of 3 years’ Semi- annual Means via pen REPORT—1886. Taste I.—Semi-Annual Solar-Diurnal 5h 6h Ch gh gh 105 | 11» +0°5 | —0-1 | —0-2 | —0°6 | —0°8 | —1°5 +04 | +04 0°0 | —0-4 | —0-2 | —0°9 +0°2 | —0'4 | —0°2 | —0°4 0:0 | —0°4 +14 | +05 | —05 | —15 |—2°5 | —2'8 +07 0°0 | —0°7 | —1°3 | —2°2 | —2°2 +11 | +07 | —0:2 | —11 | —2°0 | —1'8 +0°9 | +0°1 | —0-4 | —0:7 | —0°9 | —13 +0°6 0:0 | —0:2 | —@-4 | —0-4 | —0°9 +11 | +02 | —0-2 | —0°4 | —0°4 | —07 +11 | +02 | —08 | —2°0 | —2°8 | —3°0 +11 0-0 | —O°'7 | —1°5 | —2°0 | —22 +0°9 | +0°2 | —O'4 | —1-1 | —1°8 | —1'5 +07 | —0:2 | —0°6 | —0°9 | —1:2 | —15 +0°9 | —0-2 | —0°4 | —0°4 | —0°7 | —0°9 +0:4 | —0:2 | —02 | —0°2 | —0'9 | —07 +0°9 | —O'1 | —1:2 | —2°3 | —2°9 | —3:3 +0°9 | +04 | —O°7 | —1°5 | —2°2 | —2:2 +0°9 | +02 | —0-2 | —1'°3 | —1°5 | —2°0 MEANS OF +07 | —O°1 | —0°4 | —O-7 | —1°0 | —1°4 +0°6 | +01 | —0-2 | —0-4 | —0-4 | —0°9 +0°6 | —O'1l | —0°2 | —0°3 | —0-4 | —0°6 +11 | +02 | —0°8 | —1:9 | —2°7 | —3:0 +0°9 | +01 |—O°7 | —1°4 | —2°1 | —2°2 +10 | +04 | —0°3 | —1:2 | —1°8 | -1'8 0:0 | +02 0:0 | —01 0:0 | —0°3 —O1 | —0°3 | +04 | +02 | +03 | +04 +071 | —0°2 | —0°2 | —0°3 | —0°6 | —0°5 +0°2 | +01 | —01 | —0°5 | —0°6 | —0°8 +01 0:0 | —0-2 | —0-4 | —0°6 | —0°8 +01 | —0°2 | —0°%5 | —0°7 | —0'9 | —1:2 Variation. Greenwich and Kew. 12h | 13h | 14h | 15h | 16h | 17h | 18h | 19h | 20h | Q1h | 22h | Q3h —1°9 | —2:1 | —2°3 | —2°6 | —3°0 | —4°0 | —5°2 | —G1 | —61 | —4:2 | —0°7 | +3:7 — —1l1 | —1°3 | —1°8 | —2'2 | —3°3 | —4°6 | —5:9 | —6°6 | —6°8 | —4:8 | —1°5 | +3-7 | Normal according to Sabine. —09 | —1'3 | —1°3 | —2°0 | —2°6 | —4:2 | —5:3 | —6°8 | —6'8 | —S:1 | —1-1 | +3°3 of Wild. | —26 | —2°6 | —2°4 | —2°3 | —2°1 | —1°9 | —1°8 | —2°1 | —2°8 | —2°6 | —0°7 | +2:2 = —2:0 | —2°0 | —2°0 | —2:0 | —2°4 | —2°2 | —2-2 | —2°6 | —3°3 | —3-1 | —1-1 | +2-0 | Normalaccording to Sabine. —1'8 | —20 | —2°0 | —1°8 | —2:0 | —2°0 | —2°0 | —2°6 | —3*1 | —3-1 | —1°3 | +18 BS Wild. —1°5 | —2°0 | —2°3 | —2:7 | —3°3 | —4°3 | —5:1 | —5-9 | —6°0 | —4°4 | —1°1 | +3-2 = | —1:3 | —1°1 | —1'8 | —2°2 | —3-1 | —4°6 | —5°7 | —6°6 | —6°6 | —4:8 | —1°'8 | +3-1 | Normalaccording to Sabine. —11 | —1°3 | —1°8 | —2:2 | —2°9 | —42 | —5°5 | —6°6 | —64 | —4'8 | —1°5 | +3°3 3 Wild. . j | —2:9 | —2°6 | —2-4 | —2°0 | —1:8 | —15 | —1-4 | —18 | —2°5 | —2°6 | —0°5 | +94 -- | —22 | —18 | -1-5 | —15 | 1:5 | -1°8 | —2-0 | —2-4 | —3°3 | —3-1 | 0-9 | +2-0 | Normal according to Sabine. ~}—15 | —1°5 | —1°5 | —1°3 | —1°5 | —2:0 | —2°4 | —3°1 | —3:7 | —3°3 | —1'8 | +2°0 a Wild. } —1:9 | —1'9 | —2:0 | —2°6 | —3°0 | —3°8 | —4-7 | —5:4 | —5-€ | —4-1 | —0°8 | +31 — —15 | —15 | —1-1 | —2°4 | —2°9 | —40 | —5:1 | —5°7 | —6-2 | —4°8 | —1'5 | +2°9 | Normalaccording to Sabine. —11 | —1:1 | —1°5 | —2°0 | —2:2 | —3°5 | —4°8 | —5°9 | —6-4 | —4°8 | —1°5 | +2°6 rh Wild. 4 ~ ¢ 2:7 | —2°5 | —2°4 | —2°3 | —1°6 | —1°3 | —1:°3 | —1°5 | —2°0 | —1°9 | —O-1 | +2°6 =— | —2°4 | —2°2 | —2-0 | —1°8 | —1°5 | —1°8 | —2°0 | —2-2 | —2-4 | —2-4 | —0°9 | +2:4 | Normalaccording to Sabine. | —2°0 | —15 | —1°8 | —1°5 | —1°3 | —1°5 | —2°0 | —2°2 | —2°6 | —2°6 | —1°5 | +1°8 ” Wild. } ‘THREE YEARS: —1°8 | —2-0 | —9-2 | —2-6 | —3:1 | 4-0 | —5°0 | —5°8 | —5-9 | —4-2 | —o-9 | +3°3 | Greenwich, Summer, three years’ Means. —13 | —1:3 | —1-6 | —2°3 | —3-1 | —4-4 | —5°6 | —6°3 | —6°5 | —4-8 | —1°6 | +3-2 | Kew, Summer, three years’ (Sabine). —10 | —12 | —1-5 | —2-1 | —2-6 | 4-0 | —5'2 | —6-4 | —65 | —4-9 | —1-4 | +3-1 | Kew, Summer, hree years’ (Wild). —27 | —26 | —2-4 | —2-2 | —1-8 | —1-6 | —1°5 | -18 | —2°3 | 2-4 | —0-4 | +94 | Greenwich, Winter, three years’ Means. —2'2 | —2:0 | —1:8 | —1'8 | —1'8 | —1:9 | —2°1 | —2:4 | —3-0 | —2:9 | —1-0 | +2:1 | Kew, Winter, three years’ | (Sabine). —18 | —1:7 | —1'8 | —1:5 | —1°6 | —1:'8 | —2°1 | —2°6 | —3-1 | —3-0 | —1:5 | +1:9 | Kew, Winter, three years’ (Wild). —03 | —0-1 | —O-1 | —0-2 | —0°5 | —0-4 | —0'4|+01] 0-0 | +01 | —0-2 | +01 | (Sum.), Sabine minus Wild. | +04 | +0:3 0-0 | +0°3 | +02 | +071 00 | +0°2 | +01 | +02 | +05 | +02 | (Win.), Sabine minus Wild. | —05 | —07 | —0°6 | —0°3 | - 0-0 | +0-4 | +0°6 | +05 | +0°6 | +0°6 | +0:7 | +01 | Greenwich minus Sabine 4\ (Summer). —0°5 |—0°6 | —0-6 | —0-4 0:0 | +03 | +06 | +0°6 | +07 | +05 | +06 | +03 | Greenwich minus Sabine (Winter). —0°8 | —0°8 | —0-'7 | -0°5 | —0°5 0-0 | +02 | +06 | +0°6 | +07 | +05 | +02) Greenwich minus Wild (Summer). —0°9 | —0°9 | —0°6 | —07 | —0-2 | +02 | +0°6 | +08 | +0°8 | +0°6 | +11 | +05 Le » (Winter). ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 73 1886. REPORT 74 DIEM. SUI YOTMUOALY |P.O+ | L-0+ L-0+|9.0+|L-0+ 0+/9-.0+|\8.0+ \ ‘ouIquUy snug Yyormuoory) |¢.90+|¢.0+|¢.0+|9-0+|9-0+ 0+ }P-0 1/80 + “BAOUDIO YT PIEM suune aurqug |L.0+|G0+ |60+)0-0 |Z0+ 10+ & 0+ POFGOFIOO |) “(PIEM) savok 00149 ‘MO |G¢.6+|F-1—|0-F—|8-P—|9-b— SEHOG+|9-9+|8-9+/99+] * * *(Z) MOI ‘Courqes) savor ooryy ‘Moy. |9.3+/%-1—|8-6—|8-F —|8-F— HE+(SE+10L4+/0-2+/99+) ° * * (1) Moy “SUROTT Savak od1q} Yormusary 16.2+'/2.0—!8-—|3-F—|3-8— LEHNVGH+IGLAIE LE GO * TOTAV TION.) f. *PILM 04 | bee | | SUIPLONIT [VUMION “MO |G-SZ+ ¢1T—|L-8— 9-F— oe a 8-I—|8-1—|¢-T— | 1— |¢-T— | §-I— | LT — 6.0— Maile LO+ GLA|LE+/9-F+/F-9+/F-9+ 86+] ° * * (3) MOx “OUIGUS OF | | Surpaxooov pwuroN “MOY |9.Z+)[-1—|G-8—F-F—|0-P— 9-6 —|9-G—|8-B—|0-8— |8-1— BI |0-6—2-1—|S1— 6-0— 1.00.0 6-04 BT+|GE+)/L9+|9-94/8.9+/90+] * * + (T) Moxy “POIMUDILY) |8.6+ 9 6-Z—|8-&—|¢-—|0-8—|G-3—|8-B— |F-B—|G-B— |GS—|8-G— F-S—|0-G—|9-T— 6-0—|LO—|80+ 0.64/94) F-9+ [024/02 + 8¢E+|* * YOIAteary ‘GL8T “PILM 04 Surproooe euton *aosy |9.¢+/¢.1—|%b—|0-¢— 8-F—|0-F—|L-8—|-6—|8-T— |8-1— 1 —|8-1— | LT —|E1—|F-0 Po GO+|6-O+F BI+(E-E+/09+/9-9+/0L+1¢G+] * * *(Z) ox *OUIQ’S OF Surpazooor yeuton ‘Moy |P.-+\-1—|0-F—|0-¢—|9-F—|L-8 —|T-8 —|3-6 — |8-1— |S 1 — |¢-T— |¢-T — |: T— | LE — 6-0 — F-0— 10.0 60+ )/0-6+/L-E8+)9-9+ |0-L+)0-2+)2-6+ * (7) Most ‘yormuoaty |g.¢+|3.0—|9-8 —|G-b—|6-G—|8-8 —|6-6— 9:6 —|P-G — |F-— 8-6 — |B-S— |G-B— |B 1— E-1— 9.0— LOF|OL+ LO+|G-8+ |8E+|/EL4+/92+10-9+] ° * OLMtea.ty “‘TL8T “PITAL 0} Surprxooo [wuutoN “May |9.5-+ 8-1—0-F—|9F—|9-F—|L8—|L-E—|P-S— [81 — |S L— |G 1 —|8-1—|T-T— 6-0- |2.0— G0—|2-04|LO+ CT+/LE+|ES+)8.9+ 0-2 +/6.9+ * *(%) Mar AUIIBS 04 BUIPIONV [BUMIONT “MSL 0.8 + &1—|0-F—|LS—|9-b— 0-F—|8-8 — 19-6 —|0-6—|8-L— |8-I—|¢-T— |¢- I —|L-I— |6.0— 6.0—|8.0+ LO+F)8-T+/G-8+ 8-64 8-24 82+ )2-¢+ * * (7) May *TPOTMUGDTY) [0-+|1-0—|F-§ — |F-P— | L-F— 9-8 — 16:6 — |9-B— |9- — |6-G — |F-B— 6-3 — leo— LI-|L-L— &0— B-O+/60+F T-O+\L8+ 1-64 8.24192 + 109+ * TOT WA8.L4) ‘OL8ST ‘UVa . ieee re ik ae a 183 | uZS | yLS| yOS} y6L | uST | u2L | u9T} uSt | uFT | SE | uZL | afl | OL | u6 | u8 | us | ud | uo | yh} q | we |} ul 0 caooNr “maxyT p wp YOUNUWAALE) ' UOUDULD A 1DULNUT -LP]0S) jonuup— TT aay J, “TI Oo ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. - V. Note by the Rev. Professor Perry and Professor Stewart. Comparison of Magnetograms of Kew and Stonyhurst. The existence of two magnetic observatories not very far apart, and supplied with similar sets of self-recording instruments, affords a very favourable opportunity for discussing the lesser variations that may be detected in the simultaneous movements of the magnetic needle. A first comparison was therefore made in 1868 between the declination magneto- grams of Kew and Stonyhurst, and it was found that the ratio between the changes at the two stations wasa variable one. A further discussion of the curves of 1883 and 1884 has lately been made by the Rev. S. J. Perry and Dr. Balfour Stewart, and the results communicated to the Royal Society in a paper read on December 10, 1885. The observed differences in the declination ordinates between the turning-points of certain marked fluctuations in the curves have led to the conclusion that the fluctuations at both observatories follow the same general lawas to direction, but that there is apparently a slight difference of duration at the two stations in the case of some short period movements. In dis- cussing the tabulated measurements it was assumed as a working hypo- thesis that the disturbances are due partly to true magnetic changes and partly to secondary currents arising therefrom. The ratios of the simultaneous changes at Kew and Stonyhurst show that the angular values of the declination disturbances are in excess at the latter observatory, especially when the movement is of short duration; but these ratios appear to be independent of the extent of the oscillation. The Rev. S. J. Perry and Dr. Stewart are continuing this research. VI. Note by Professor Stewart and W. L. Carpenter, Esq. We have reduced other four years of Kew declination disturbances after the method described in the last report of this Committee, and have obtained the following result from the two series of four years each :— Supposed connection between disturbances and the Moon’s age. (0) =new (4) =full moon. (Oye) Core Cy Toe er() see (6). - 1) 1866-69 . 88 91 78 64 52 69 74 75 WA0=to «fit “114 “104 95 83 94 107 101 From this it will be seen that the results obtained from both series agree together in exhibiting the same sort of fluctuation. We have likewise reduced the four years of Kew declination disturb- ance, 1870-73, with the view of determining whether there is any apparent connection between wind values and magnetic disturbances. In doing this we have adopted the following procedure :— 1. We have obtained, by the kindness of the Kew Committee, the total amount in miles gone over by the wind at Kew for each day of the years 1870-73, and have then converted these into daily averages of three days. Let us call this table A. 76 REPORT— 1886. 2. We have next obtained a table B, where each day’s value is the average of 25 days of table A, all being properly placed with respect of dates. 3. Taking the difference between the entries of tables A and B, we > obtain a series representing departures from the mean—plus when in excess, and minus when in deficiency—which may be taken to represent wind weather. 4. The declination aggregate daily disturbance numbers have been treated in exactly the same way as the wind numbers, and the differences obtained may be taken to represent disturbance weather. 5. The values representing wind weather have then been formed into series of twelve terms each, so chosen that maximum wind values come together at the middle of each series. The series are then added up. The result is given in (a). 6. The declination disturbance weather values have then been arranged into series of twelve each, so that each entry is two days previous in date to the corresponding entry in (a). Call this (/3) when added up. 7. The values representing wind weather have next been formed into series of twelve terms each, so chosen that minimum wind values come together at the middle of each series. Let this be added up and called (y). 8. The declination disturbance weather values have then been arranged into series of twelve each, so that each entry is two days previous in date to the corresponding entry in (y). This is added up and called (6). The results of these tables are given below :— (a) Wind weather arranged so that max. values represent middle of series. — 2384 — 1655 —101 4 2205 + 5935 + 7431 + 7022 +4157 + 2401 —360—1667 —2196: (2) Dec. disturbance values so arranged that each entry of ((3) is two days previous to each entry of (a). —2220—652 + 245 +41110+919+ 693 + 1007 +466 +1067 +588 + 33 — 186. (vy) Wind values arranged so that min. values represent middle of series. +2535 +1114—1017 — 3393 —4872 —5312—5177 —4740—3322 —1680+107443196. (6) Dec. disturbance values so arranged that each entry of (6) is two days previous to each entry of (y). +679+177 —474—1022 —1227 —587 —260—367 —1041—980—5385+4116. From this it would appear that high disturbance values correspond with and slightly precede high wind values. It is our intention to reduce all the available Kew observations in this way, and ultimately to present the result to the Royal Society. ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 77 VII. Report to the Secretary of the Committee of the British Association appointed for the purpose of considering the best means of comparing and reducing magnetic observations. In the suggestions which I submitted to the Committee last year I proposed that the method of spherical harmonics employed by Gauss should be applied to the periodic variations of terrestrial magnetism. I have in the course of the past year examined by this method the principal term of the solar diurnal variation; and I hope that the results obtained will induce the Committee to continue the examination in greater detail of the same variation, and also the other periodic changes. Assuming that the Committee is willing to adopt a course of action which must necessarily lead to results of primary importance, I venture to submit to them more definite proposals. If we had eight magnetic stations separated as far as possible we should be able to obtain a fairly complete expression of the general distri- bution of magnetic potential on the surface of the earth. For the expan- sion in spherical harmonics, including terms of the third order, involves fifteen constants, while the horizontal components of magnetic force at each of the eight stations would give us sixteen quantities to determine them. As far as I can judge at present, periodic variations are not much affected by local circumstances, and therefore harmonics of the first three orders will in all probability be sufficient, as a first approximation at any rate. After obtaining the expression for the variable part of the poten- tial, we can easily, with the help of the vertical component of magnetic force, determine the question whether the cause of the disturbance has its seat inside or outside the surface of the earth. J think, therefore, that we should endeavour to obtain a complete record during a period of about ten years of the elements of terrestrial magnetism at eight stations, and that these should be reduced in exactly the same manner, under the super- intendence of the Committee. As it is important to proceed without delay, we must choose stations at which self-registering instruments are at present in existence. I think the following will be the most suitable: Lisbon, Greenwich or Kew, St. Petersburg, Bombay, Mauritius, Melbourne, Zi Ka Wei (China), Toronto, or Washington. It is a matter of regret that South America is not re- . but I do not think the deficiency is sufficiently great to justify elay. I should propose, then— (1) To write to the chief observers at these stations at once, asking them for such information as will enable us to judge whether the instruments are in good condition, whether sufficient precautions are taken to elimi- nate temperature variations, and whether they are willing to pay par- ticular attention to the magnetic instruments for a period of ten years. (2) To ask these observers how far they are willing to undertake the reduction of their observations according to a scheme submitted to them by the Committee, and, in case they cannot undertake this, whether they are willing to forward to the Committee the necessary records. (3) To obtain an estimate of the cost of the reductions, which will have to be undertaken by the Committee. 78 : REPORT— 1886. I cannot help thinking that on inquiry a good many difficulties which have been raised will be found to disappear, and that in view of the great importance of the subject the necessary funds will be forthcoming when- ever a definite scheme is proposed which will lead to certain results. The secular variation of terrestrial magnetism will probably require a different treatment. Captain Creak has’informed the Committee that a large number of observations of declination, inclination, and total force distributed over the world have been collected by the late Sir Frederick Evans and himself, and that he has already exhibited on a globe at a recent soirée of the Royal Society some leading results of the distribution of the secular change for the epoch 1880. The Committee should, in my opinion, collect and tabulate all available records of the secular varia- tions of the three components of the magnetic force. We cannot decide on the best method of reduction until the material has been collected. ARTHUR SCHUSTER. VIL. Remarks on a Provisional Working Hypothesis. By Professor Banrour Srewarvt. 1. From various quarters there have been brought together the elements of what may be termed a provisional working hypothesis with respect to the main causes of the periodical variations of terrestrial magnetism. In this hypothesis it is supposed that electric currents in the upper regions of the atmosphere may be the main immediate causes of the periodical non-disturbance variations of the magnet, while small but abrupt changes in the magnetism of the earth along with secondary or induced currents in the earth’s moist conducting strata and also (occasion- ally at least) in the upper atmospheric regions, in times of auroras, called forth by these changes may account for the disturbance variations of the magnetic needle. It will thus at once be seen that the regular variations are supposed to be mainly due to a cause above the needle, while the irregular variations are supposed to be mainly due to a cause beneath the needle. 2. The electric currents in the upper atmospheric regions which cause the regular variations are supposed to originate in the motion of a conductor (rarefied air) across lines of magnetic force, and it is supposed that such electric currents will vary i the first place according to the power of the sun as exercised in producing these atmospheric motions, and in the second place according to the temperature of the moving strata, it having been remarked by Professor Stokes that such strata will become better conductors as their temperature increases. This increase in the temperature of such strata may either be due to an increase in the sun’s radiation of such rays as are absorbed by these strata, or to a change in their constitution with respect to aqueous vapour, a substance which may be presumed to possess strong absorptive power for certain rays. 3. With regard to the solar diarnal variation, the most prominent feature is the very simple character of this variation as far as the element of declination is concerned. For the average of a year, and for all but high latitudes, this variation may be represented as if due to positive electric currents in the upper atmospheric regions flowing during those hours when the sun has most power from the equator to the poles ; that is to say, from ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 79 south to north in the northern, and from north to south in the southern hemisphere, and producing about 2 P.M. a maximum westerly deflection of the north-seeking pole of the magnet in the northern hemisphere, while that in the southern hemisphere for the same pole is of an opposite character, being easterly, 4, Again we know that the air in the upper atmospheric regions travels from the equator to the poles, forming (in those regions) a south- west current in the northern hemisphere, and a north-west current in the southern hemisphere, these being, in fact, the well-known anti-trades. If, then, owing to their passage across the earth’s lines of force, these moving conductors are animated by electric currents, these currents must, according to the well-known law, be in such a direction as to stop the atmospheric motions. ° 5. For the purpose of the following argument we may without sensible error imagine the magnetic earth to be really similar to the model that is sometimes used to represent it; that is to say, we may regard it asa globe wrapped round continuously with insulated wires all in the same direction, and conveying a current, the circles of these wires being small near the poles, and, of course, large at the equator. If we should take a bird’s-eye view of this system from above the point which represents the north pole (which corresponds approximately to the south pole of a magnet), we should find that the positive current in the wires would circulate in the direction of the hands of a watch, ascending on the east and descending on the west side. Such hypothetical currents may, there- fore, be imagined to move along the earth’s surface from east to west. 6. Let us now take the upper systems of atmospheric currents and consider that element of their motion which is from west to east. This motion is common to both systems. If in the northern hemisphere these upper winds be animated by a positive electric current going north, this current will be attracted by the hypothetical magnetic current on the west side and repelled on the east; that is to say, there will be a tendency to stop the easterly motion of the atmospheric current. In the same way it may be shown that if in the southern hemisphere the upper winds be animated by a positive current going south, this will tend to stop the easterly motion of the atmospheric current. 7. It thus appears that the electric currents with which, according to this argument, the upper trade-winds in the two hemispheres ought to be animated are precisely such as will account for the solar-diurnal variation of declination, this being alike the most prominent and the most simple feature of the solar-diurnal variations. 8. While it is advocated that the provisional working hypothesis thus accounts, as far as direction is concerned, for the positive currents going north and south—which are presumed to be: the main causes of the diurnal variation of declination—it is also necessary to remark that such currents will naturally present a decided diurnal fluctuation. Indeed, if ' this were not the case, they could not properly account for a variation one marked feature of which is its prominence during the day as dis- tinguished from the night hours. Now we may conceive that the upper atmospheric currents may be stronger, and will at any rate be better ‘Sir J. Henry Lefroy has long been of opinion that the key to the magnetic movements in both hemispheres is to be found by studying the simultaneous effects in both produced by the action of the sun on the equator (see p. 182 of his ‘Survey,’ 1851). 80 REPORT—1886. conductors when heated by the sun, and hence, through a diminution of resistance, the electric current will be increased. The curious similarity detected by Senhor Capello between the diurnal variation of the magnetic dip and that of the tension of aqueous vapour (see Appendix Ii. to this report) might perhaps seem to point to a variation of absorptive power, and hence of electric conductivity brought about in certain atmospheric strata by the carriage of aqueous vapour. Again, Sir G. B. Airy (see appendix to the Greenwich observations, 1884) has expressed his opinion that the diurnal magnetic imequality is due mainly, if not entirely, to the radiant heat of the sun, and he is also led to imagine that the magnetic effect of the sun’s heat upon the sea is considerably greater than the effect on land; while again Sir J. Henry Lefroy (see Appendix ITI. to this report) having observed a difference in the time of turning between the solar-diurnal variation of declination at Toronto and at Greenwich, has expressed his belief that this difference is due to the fact that these two places are differently situated with regard to the Atlantic. 9. The fact that the solar-diurnal variation is greater at times of maximum than at times of minimum sun-spot frequency is explained by the advocates of this hypothesis on the assumption that not only is the sun most powerful on the former occasions, but that the solar radiation then contains probably a larger proportion of such rays as are absorbed by the upper strata of the atmosphere, while the composition of these strata with respect to aqueous vapour may likewise be such as to cause an increased absorption. This increased absorption means an increased temperature, and hence an increased conductivity. 10. It has moreover been adduced in favour of this hypothesis that the tendency seems to be, as pointed out by Mr. William Ellis and by Pro- tessor Stewart, that changes in the range of the daily variation of magnetic declination lag behind corresponding solar changes in point of time. This kind of behaviour is apparently inconsistent with direct magnetic action of the sun operating as the chief cause, and points rather to some indirect influence, probably caused by the radiant energy of the sun, inasmuch as the changes and turning-points of such indirect influences due to radiation are well known to lag, in respect of time, behind the corresponding changes and turning-points in their cause. This subject demands further attention. 11. Hitherto we have been considering that portion of the motion of the upper atmospheric currents which is from west to east in both hemi- spheres. Let us now consider that portion of such motion which is from south to north in the northern, and from north to south in the southern, hemisphere.! Now, here it may be well to remark that it seems quite possible to conceive a set of currents to exist in the earth’s atmosphere without exhibiting a considerable diurnal variation. Let us take, for instance, an ordinary electric current, say of a circular shape and horizontal, and heat it by causing some source of heat, such as a lamp, to travel slowly round it with a definite rate of progress. It will bé evident that we shall have (assuming the current to be otherwise constant) no variation in flow due to this heating effect. In like manner, if there be electric currents in 1 The discussion of this point is almost identical in wording with a similar dis- cussion brought by Professor Stewart before the Physical Society. EE ———————— ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 81 the atmosphere which circulate round the earth in the direction of parallels of latitude, such currents will not be subject to any considerable solar-diurnal variation. For, while the conductivity of a given region would vary according to the position of the sun with regard to it, yet the whole circuit round the earth, which would always embrace a region affected by the sun, would not have its total resistance altered, or at least not greatly altered ; and, as there would be no cause for much alteration of the total electromotive force, there would be no great reason for incon stancy of current—in other words, no great solar-diurnal variation. 12. For the purpose of the following argument, we may consider the earth to be at rest (7.e., devoid of rotation), and imagine that the sun circulates round the equator in twenty-four hours. As a consequence of solar influence we shall have convection currents in the upper regions of the atmosphere flowing from the equator northwards and southwards toward the poles. Whether these currents reach the poles or come down in some intermediate region may be left an open question. Now, such currents will not only be conductors, but they will form a movable system of conductors, which we may suppose to be created at the equator when they rise into the upper regions, and destroyed at the poles or those intermediate regions where they descend. 13. Again, for the purpose of this argument we may, without sensible error, regard the magnetic globe in the way already mentioned ; that is to Say, as represented by a small globe, wrapped round with wires, conveying currents that go round it from east to west. Now, if an external in. sulated circuit of wire a trifle larger than the diameter of this globe be supposed to travel from the equator to either of the poles, it will leave behind it more convolutions of the primary globe current than it approaches, and will therefore be traversed by an induced current in the same direction as that of the primary; and the continuous travelling of such an external system might be supposed to increase the magnetic power of the globe. Applying the same sort of reasoning to the earth and to the convection currents under consideration, these may be imagined to be traversed by equatorial electric currents, the tendency of which in both electric hemispheres would be to increase the general magnetism of the globe. For the reason already given such currents would have little solar-diurnal variation, but yet they would be dependent upon the state of the sun, and would vary with it. For imagine a chan ge to take place inthe radiation of our luminary, producing an excess of such rays as are greedily absorbed by the upper atmospheric regions, there would be (as already remarked) a sensible increase in the conductivity of these regions, even if the electromotive force remained unaltered; and hence there would be an increase in the supposed equatorial current. In other words, such currents, while presenting no great diurnal variation due to the carriage of a constant sun round the earth, would yet be eminently susceptible to _ any inconstancy in the sun itself. 14. Now here it will be asked, Have we any such phenomenon con- nected with terrestrial magnetism ? The reply to this question will be an affirmative one. The late John Allan Broun has shown that we have changes in the mean daily value of the horizontal force, which are simnl- taneous and in the same direction at places on the earth’s surface very far removed from each other; and the author of these remarks has endeavoured to show that the changes of this nature as recorded by Mr. Broun depend, as far as we can judge from somewhat imperfect records, 1886. G 82 REPORT—1886. upon the state of the sun’s surface, an increased area of spotted surface coinciding apparently with increased values of the daily means of hori- zontal force all over the earth. While such currents might be supposed to possess, as a whole, no dis- tinct daily variation, yet at the time when the sun heats a tropical region it might be supposed to increase the relative conductivity of that region with respect to that of the atmosphere nearer the pole. It would thus divert to the heated region an unusual proportion of the whole current, so that we should have a maximum of horizontal force near noon in the equatorial, and a minimum at the same time in the polar regions. This is probably the case. } 15. One chief object in giving prominence to this part of the subject is with the view of advocating that the Gaussian method of analysis should not be applied merely to the solar-diurnal variation of the three magnetic elements, but should likewise embrace a consideration of the simultaneous variations in the mean daily values of the elements at various stations. We must, in fine, consider the possibility at least of there being in the upper atmospheric regions, not merely currents which present a marked solar-diurnal variation, but others that have no marked solar- diurnal variation, while yet they may be highly susceptible to changes in the sun. The double method of treating mathematically not merely the solar-diurnal variation, but likewise the simultaneous changes in the mean daily values of the elements, would thus appear to be necessary and sufficient for giving us the required information. 16. If weturn from the solar-diurnal variations to those caused by the moon, we find in this region likewise an attempt to explain the phenomena by the same working hypothesis. It has been remarked by Dr. Schuster that we live at the bottom of the atmospheric ocean, where lunar tides will necessarily be small, and he imagines that in the upper regions of the atmosphere the motions caused by lunar tides may be very considerable. Such motions would be subject to'the same magneto-electric laws as those caused by the sun, and we might therefore expect a lunar semi- diurnal magnetic variation, such as, in fact, we have. The late John Allan Broun has shown that the moon’s magnetic effect varies approxi- mately as the inverse cube of the moon’s distance from the earth, a con- clusion that would seem to point to some sort of tidal influence as the cause of this effect. 17. Again, if this tidal influence be seated in the upper atmospheric regions, it should be greater during the day (when these regions are heated, and so become good conductors) than during the night. Now, ‘Broun was the first to point out that the semi-diurnal lunar variation at Trevandrum, in India, is subject to this law, and his results have lately been confirmed, in an independently conceived investigation, by Mr. C. Cham- bers, of Bombay. We might likewise expect that the lunar variation, like the solar one, should be greatest at times of maximum sun-spot frequency, and there is some reason to think that this is the case, although the fact is not yet definitely established. 18. There seems, therefore, reason to believe that the diurnal varia- tion of any one magnetic element—the deciination, for instance—may be due to the joint action of several causes, which we may, perhaps, represent as follows :— In the first place, the sun may act in producing atmospheric motions in the upper regions ; this would cause a solar diurnal magnetic effect. ee - ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 83 Secondly, the moon would produce tides in those regions, which would be the cause of a lunar semi-diurnal magnetic effect. Thirdly, the sun, acting as the moon does, would likewise produce tides which would be the cause of a solar semi-diurnal magnetic effect. Fourthly, these various effects would be increased during those hours when the sun is powerful, inasmuch as the upper atmospheric regions become better conductors at high temperatures. 19. If we now leave the regular variations, and turn to magnetic dis- turbances, there seems reason to suppose that the earth, like any other magnet, may be subject to small and abrupt changes of magnetism, and it is quite conceivable that such changes may produce secondary currents in the moist conducting strata of the earth, and likewise in the upper atmospheric regions. We know, as a matter of fact, that there are such earth-currents, and the observations made at Greenwich show that the are intimately associated with the disturbances registered by the self- recording magnetographs. 20. The late Dr. Lloyd was the first to remark that ‘ the rapid changes of the earth currents are much greater in proportion to the regular daily changes than the corresponding movements of the magnetometers.’ We may perhaps interpret this to mean that a small but abrupt magnetic change is associated with a larger earth-current manifestation than another change of the same size, but of a more gradual nature. This would appear to be in favour of the view that such earth currents are secondary currents due to small but abrupt changes which take place in the magnetism of the earth. In conformity, too, with this hypothesis, eases may be pointed out where the magnetic disturbance, while rapidly varying, is yet altogether on one side of the normal, and where the cor- responding earth currents pass alternately from strong positive to strong negative. 21. Quite recently (see Appendix V. to this report) the Rev. Professor Perry and Professor Stewart have brought before the Royal Society the results of a preliminary comparison between the fluctuations of the declination at Kew and at Stonyhurst (neighbouring stations), and have derived the following conclusions :— (1) In the very great majority of cases the angular value of the declination disturbance is greater for Stonyhurst than for Kew. (2) The ratio es is certainly greater for disturbances Ww of short than for those of long duration. _ Ifwe add to these conclusions the fact noticed by these observers that all the disturbances occur in couplets, we may be disposed to agree with them that in the case of disturbance as exhibited by a suspended magnet there are probably two causes at work, the first of these being a change in the magnetism of the earth, and the second an induced current due to this change. 22. It would thus appear that in this provisional working hypothesis the principle of current induction is brought forward with the object of explaining both the regular and the irregular magnetic fluctuations. It is sought to explain the former by the hypothesis that in the upper atmospheric regions we have conductors moving across lines of magnetic force, and hence animated by a current. Itis sought to explain the latter on the supposition that small but abrupt changes of the magnetism of the earth by a method similar to that in a Ruhmkorff’s coil cause secondary G 2 84 REPORT—1886. currents in the moist conducting strata of the earth’s surface and in the upper atmospheric regions, which currents, as well as the magnetic change which causes them, will, of course, influence a suspended magnet. 23. There is still left the question, Why should there be small and rapid changes of the earth’s magnetism? In reply to this it is argued that we must regard the earth as we would any other magnet, the only difference being one of size. Now, there are at least two known causes which may operate upon a magnet to change its magnetic state. These are first, mechanical disturbance ; and secondly, a change in the electric currents in whose field the magnet is placed: and it is asserted that the changes which take place in the magnetism of the earth should be studied from these two points of view. It is the second of these causes that has hitherto been chiefly investigated, and magneticians have succeeded in showing that disturbances vary with the state of the sun’s surface, witl the time of the year, and with the hour of the day. Possibly, however, considerations connected with the first of these causes might seem best to explain the second portion of the preliminary results obtained by Messrs. Stewart and Carpenter (see Appendix VI. to this report). 24. In conclusion, perhaps the strongest objection to this hypothesis is that which questions the possibility of electric currents being produced in the upper atmospheric regions. It may be said that while undoubtedly rarefied air is a conductor of electricity, yet it is not a good conductor ; and where can we look for sufficient potential to drive such currents through these regions? . To this it may be replied that as a matter of fact we know that there are visible electric currents in the upper atmospheric regions which occur occasionally at ordinary latitudes, and which are very frequent if not continuous in certain regions of the earth. These are known as the Aurora which, both with respect to the time of its occurrence and to the disposition of its beams, manifests a close connection with the phenomena of terrestrial magnetism, occurring at ordinary latitudes only when there are great magnetic disturbances, and the disposition of its beams having a distinct reference to lines of magnetic force. Besides. considerations of a mathematical nature induce us, as we have already seen, to suppose that the solar-diurnal variation is due to electric currents in the upper atmospheric regions. We are, therefore, justified in asserting that there is no impossibility in conceiving a set of electrical currents intimately associated with certain phenomena of terrestrial magnetism to exist in the upper regions of the earth’s atmosphere. IX. Examples of the Application of a Modified Form of Sabine’s Method of Reduction of Hourly Observations of Magnetic Declination and Hori- zontal Force to a Single Quarter’s Registrations of the Magnetographs at the Colaba Observatory, Bombay. By Cuartes Cuampers, F.2.S. On the invitation of Dr. Balfour Stewart, the Secretary of the Com- mittee appointed by the British Association to consider the best means of comparing and reducing magnetic observations, I submitted last year, for the Committee’s consideration, some remarks which had the honour to find a place in their Report to the Association. Amongst the sugges- tions which I then made was one for a trial application of a somewhat elaborate process of reduction, the results of which it was anticipated would, in some respects, be as definite and informing when derived from en Sh i ed ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 85 a comparatively short series of observations as those of Sabine’s rougher method when derived from a much longer series of observations. Such a trial I have since been able to make upon the hourly tabulations from the registers of the Colaba declination and horizontal force magneto- graphs for the quarter November 1875 to January 1876; and the results are of so highly satisfactory a character, and bear so directly on the inquiry upon which the Committee are engaged, that I deem it my duty to place an account of them before the Committee. The process may be described as follows :— 1. Tabulations of hourly ordinates are entered upon monthly abstract forms (Form A), which have the hours of the day marked at the head of the columns, and the days of the month at the left-hand side of the lines,! and upon these ruled forms the daily mean is taken and entered in a column at the right-hand side of the twenty-four hourly entries of each day, and the mean for the month of the entries in each hour column is taken and entered at the foot of the column. Let us suppose this to have been done for a given month, and for the two preceding and two following months. 2. Take the mean of the daily means for the first fifteen days of the same month and the last fifteen days of the preceding month as the mean ordinate for the beginning of the former month, and, for the present, let the excess of the mean ordinate for the beginning of the next month over this mean ordinate be taken to represent the progressive increase of the ordinate for the given month, whether arising from instrumental change or from secular or annual variation, and in allowing for such increase treat it as growth at a uniform rate. 3. Ona blank strip of ruled paper cut out from one of the columns enter the proportional corrections for progressive increase, to reduce the tabulations to the standard of the middle of the month; these corrections will be zero for the middle of the month, and equal positive and negative numbers at equal intervals before and after the middle of the month, and the sum of these for the whole column will be zero. The strip is to be placed close up to each column in succession for reference in the operation of separating disturbed observations. 4, Apply Sabine’s method of separating disturbances to each hour column in succession, taking account of the corrections for progressive increase entered on the loose slip, and calculate final normals. The separating values adopted are for declination ‘048 inch of tabulation or 00150 of force, and for horizontal force ‘078 inch of tabulation or ‘00334 of force. 5. Substitute for each disturbed tabulation the higher or lower limit for that hour and day of an undisturbed tabulation according as the dis- turbance is positive or negative. The deviations of the disturbed tabu- lations above the higher or below the lower limits respectively are to be called positive or negative ‘ disturbances without the limits,’ and the laws. of their variations are to be determined by the method that Sabine applied to his ‘larger disturbances.’ In what follows we are to confine our attention to the original numbers entered upon Table A, except where these have been replaced, in the case of disturbed tabulations, by the higher or lower limits. ) If the continuity of the record has been interrupted during the month, either by accident or by instrumental adjustments, due allowances must be made to render the whole month’s tabulations comparable before proceeding further. 86 REPORT— 1886. 6. Construct now a new table (B), each entry in which is the 29-day mean of the numbers for the same hour in Table A, viz., of the numbers. for the day of the entry and of the fourteen preceding and fourteen following days. The numbers of Table B for all the hours of a given day we may take to represent very approximately the mean solar-diurnal variation—plus a constant—for that day, the average extending over the lunation of which that day is the middle day. They will be affected by progressive change of the values of the tabulations and by disturbance within the limits. 7. The excesses of the numbers of Table A over the corresponding numbers in Table B, plus a constant round number, are now entered on a third table (C). The numbers in this table will be affected only by that part of the solar-diurnal variation which goes through a cycle of change in a Junation, and by disturbance within the limits. On the left- hand margin of table C mark the days of the moon’s age, the number 1 being placed opposite the first day of which at least a full half follows the time of new moon, and the other numbers, in order, up to 29 or 30. If table C were calculated for each month of a long series of years it would be practicable to re-arrange the days in tables, of which there would be one for each day of the moon’s age in each month, with a probability of obtaining characteristic diurnal variations from the numbers of each table ; but as the trial calculations extend over three months only, these (November to January) were grouped together, and the days of the moon’s age were arranged in eight groups as follows :— Group (0) @) @) @) (4) () (6) (7) 29 3 6 10 14 18 21 25 Days of the 30 ih 11 15 22 26 Moon’s age 1 4 8 12 16 19 23 27 5 9 13 17 20 24 28 Thus eight tables were formed corresponding to the times of the four quarters of the moon, and to the four intermediate phases, and the numbers of Table C were duly distributed amongst them.’ The hourly means were taken of all the numbers on each of these tables, and them the excesses of those means above the general mean for the twenty-four hours of the same table, and finally these excesses were converted from inches (of tabulations) into m.g.s. units of force. In this way were ob- tained the excess solar-diurnal variations for each of the eight phases of the moon. From these were calculated the luni-solar-diurnal variations fe and f;-(/) of the formula nr (2m foal) 008 2( 55 ) +feo(2) sin 2(3t) 1 By inadvertence the last three days of January, which formed part of a fourth lunation, were left undistributed; so that the results will be for the three lunar periods from November 1, 1875, to January 28, 1876. Re ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 87 where h is the solar hour, P is the mean period of a lunation, and ¢ is the age of the moon. Designating the variations for the eight different phases by (0), (1), (2)... - (7), we have _@-@)+@)-() fe(h)= + pa 2 OW) 4 fos And the results for the quarter November 1875 to January 1876 are— Solar |yidnight| 1 | 2 | 8. | 4] 5 | 6 | 7 | 8 | 9 | 10) 11 . “ bo z 0004+ | -000 +] -000-+ | 000+ | -000-+ | 000 + | -000+| 000+ | -000-+ | 000 +| ‘000 +} °000+ ey oh) 1 O0eh | 08 08 08 [00 04 +02/+05|+16|+20}+11}—05 c2 =I a ~ | E Fig | +97 |+06| +09] +04|/—04 |—02/—01| 00 /—05|—10|—06} + 07 S . | a o o 8 | f., (| +08 "|—04)+01/+02|—01 |—O1 | 06 | +11) +37 |+ 46)+25) +13 & c2 g Bn 67 ie} = 16> = 16) 4.05; 4-05 | 08-16} 15 |= 24). 00 (rey 56 +55 ay 8°2 2 \ =z Solar 7 | - v. hore Noon 13°) 44°) 15°] 16+) 17" a8") 19) 207] 2h) 22") 2s = ee A pn) a RRR Ae Wa) ce 2 NE | oe erat S 000+ | 000+] -000+ | 000+] -000 +] 000+] 009+) 000+ | 000+) -000+| -000+-| -000+ a Fae) |) Ee |—20)—14 | — 4 | 08 4 0) 4-02) 4-01 +02'—01/—02| 00 Sg Ee | 3 ~ E Ff. | +12 [+18 |—08|-17 |—13 |—05) +03) +08 +01 +01|+04/+08 3 32 a ih. (h) —04 |—13}—25|—21|—12]—04]—15|—14|—09 |—10/+03)| 00 e2 if. (A) +47 |+35/4+21|—02]—09|—15]—05 |—17 |—31 |—19 |—28 |—10 s'2 Horizontal Force 88 REPORT—-1886. These numbers are curved (in black) in figs. 1 to 4, and on the same forms are curved (in dotted lines), for comparison, the results of a similar treatment, but by Sabine’s rougher method, of the long series of eye ob- servations made in the winter quarters of the period 1846-0 to 1871-0 in the case of the declination, and of the period 1846-5 to 1873-0 in the case of the horizontal force.! We see at a glance that the black curves have the same general characteristics as the respective dotted curves, with only such deviations in form and range as might well be expected to be found in the real features of the variations of individual quarters. They thus confirm the evidence afforded by the longer series of observations that there is in natwre a magnetic periodicity of the kind that we have called the luni-solar- diurnal variation; but their special significance, and that to which we would at present particularly direct attention, lies in the indication which they afford that it is possible, by applying a suitable process of reduction, to utilise short series of observations for purposes requiring a degree of nicety that is quite beyond the powers of the older method. It may be worth while to mention here that each quarter’s reduction, carried out in the manner described above, occupies an Indian computer of very ordinary capabilities about 360 hours. This includes the calcu- lation of the luni-solar variations both for declination and horizontal force. The computer of a temperate climate, with his greater natural energy and better surroundings, would, of course, accomplish the work in much less time. Examples are appended hereto of the construction and computations of Tables A, B, and C, and of the combination of days belonging to the (4th) phase of a lunation; also of the calculation of the luni-solar-diurnal variations. In the last calculation the variations are taken after instead of before the combination of the numbers for the several phases; this is to avoid the inconvenience of having to deal with positive and negative numbers. The curves of fig. 5, exhibiting the regular solar-diurnal variation of horizontal force for each day of the month, are constructed from the 29-day means of Table B. 1 In the curves for declination as sent by Mr. Chambers, the signs as given above are reversed. 36” Report Brit Assee IS86 Plates a eS f (h) Declination... ${W) Bombay Astronomical Hours. aT Ae ao ea ‘4 52 SS te = wes See iE Ba Se Pe ee ee es 2 vs es SSE eSS Horizontal foree:................8 (he) mS ae Ta os SSS22 =aam eae patios Se ee ores Ge SSE ——— 3350 ee ote col So SSS, 50S=== = Soe oes oe t rt 7H = 5 i eA = 35EL SE pees MMM EES! See =a \ jen Al se Pee ciel SSS SESE ease se er te aa coca ace oo a a ert ett A ts ae aed Sn one ane At tA Qen a Sess | ea pa ied ima a ot Horizontal lorce 1346 5 to 1813 0.-Thescaleis ir m-g-s. units of tirce, oportiswoode &C Lith. Landon Mngtrating Report onthe bestmeansotlemparingé Reducing Magnetic Observations. 56" Keport Brit. Assoc 1886. Plate eee ope brit Assoc 1056. 0 <= Bias vartation of Hortézontal force tor cach day of Novernber 78835. Lombay Astronomical Hours. TS e Scale (arinches of tabulations) tor the day. 89 ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. — | — {802 | 289. | G99. | 89 | h9- | HE9- | FED. | 8Z9- | PE9- | L29- | FSI. | 1Z9- | BZ9- 19: 829. | S69. | ¥29- | 629. | TPO. | 6F9. | BG9- | F99- | 699. | GED. Té — | — | TP9- | 629" | 069. | FI9- | LTO. | LI9- | T39- | GZ9- | S39. | 219. | 819» | FID | SLO. GT). 9T9- | 8T9- | 819+ | 8Z9- | 8E9 | F9- | FG9- | G99. | S19. | 699 | OF — | — | 0G9- | OF9- | #29. | 919. | 619. | 09. | Z9- | BZ9- | ESM. | ST9. | FLD. | PID | STO. 9T9. FIO: | TT9- | 119 | #09. | L39- | 099. | LL9- | 69. | FOL. | 269. 63 — | — |899- | §99- | Th9- | TE9- | L69- | $29. | G9. | 619 | 09 | GT9- | L09- | 619. | LT9- 8T9- 909+ | 09. | 29 | E39. | 9F9 | 299. | 169 | SEL» | GIL. | SOL. 83 — | — | T69- | G99 | OF9- | GZ9- | 69+ | 6Z9- | TED | SED | OT9 | OZ9- | S19. | F09- | OFD- ggc. 969. | T9G- | FSG. | 68S. | PEI | 699. | OL9- | S69. | SOL | 969. 13 — | — | 199+ | 899. | G29. | G39. | 19 | OT9» | 609. | G09. | FO9- | G09- | €09- | €69. | 89. cael ¥8&- | PFO. | G9. | 0S9- | PFI | OS9- | G89. | EOL | 9OL- | FEL 9% — | — | 9GL- | L89- |999- | TP9- | €Z9- | 6E9- | 6Z9- | 6Z9- | TE9- | 69. | €19- | 6L9- | 669. 689. 9€9- | 089+ | 689. | PES. | 639 | 089 | OGL. | LEL- | LL | LEL GG — | — | €2- | LOL. | 169. | 029- | FL9- | 029. | 699. |399- | 199» | 099» | 199. | 099+ | 699+ 099- PLO. | G89- |8L9. | GL9- | O69 | LOL. | GSL- | T#L- | OL | OSL FG — | — | OPL- | TIL. |829- | 699- | TL9- |029- | 899- | 299- | 499. | 299- | 899- | #99. | 999+ 199- 899- | 999- |€L9- | 629. | €8% | TOL. | STL. | TFL | T9L- | O9L- &% — | — | SG. | LOL. | $69. | FL9- | 699- | G99. | €99- | €99- | €99- | 199. | 999- | 699. | $99. $99. 199+ | 899+ |899- |OL9- | #89» | O0L- | ES- | SFL | LOL | GOL. &% —|— |0S2- | GIL. | 919. | F99- | €99- | 199- |8G9- | 99. | 299» | #L9- | 919+ | ZL9. | GL9- 089- | [89: | 989 | €69- | E02. | OTL | SEL. | FOL | T8L- | LOB | 66L- 1&3 — | — | PLL. | 98L- | T69- | 629» | 8L9- | FL9- |GL9- | 9L9- | EL9- | E19» | GL9- | SL9- | 9L9- €19- T89- | 289. | #69. | 069. | LOL- | SEL. | LFL. | SLL» | BBL | OLL- 02 —|— |09L- | TEL | ZOL- | F89- | 9L9- | 229. | LL9- | OL9» | E19» | FL9- | GL9- | BL9- | 8L9- 989- | 069- | 169» | 00L- | G69. | LL9- | #69. | LIL. | SFL. | TPL | OTL 61 — | — | OTL | 069-1 | 189-1 | 29-1 | 929-1 | 6S9-T | $99-T | 699-1 | 929-1 | 099-1 | 029-1 | 899-L | $99-T] 899-L | TL9-L} $29-T| G89-T | 889-L| 889-1 | GOL-T} S22-L] 622-1] E221] 992-7 81 aye 21 ow ano Ra = 6 8 Z 9 g Li § id I 0 &% (a4 1&4 06 61 81 LT 91 ST FL &T rae IL or TID B | 8 eqe[op # ‘ydnabhojauboyy 29107 yoxwozwopy fo (sayout wr) suoynngny, fo povusqy fymoxT “GZgy ‘1aqoj0Q fo yzuogy ‘inquog ‘hwopnasasq¢ quauusan0y —' (spsomyong ponuyuod) W XTAaVy, 90 REPORT—1886. Taste A.—Government Observatory, Bombay, Month of November, 1875. crease in the month of No- | vember. 1875 | Corrections for progressive in- ra OH aa |.” 5 Date 1 1-740 2 712 3 614 4 644 5 654 6 665 7 669 8 699 9 634 10 655 ll "634 12 661 13 610 14 686 15 650 16 662 17 660 18 670 19 651 20 650 21 599 22 544 2 567 24 BOL 25 593 26 617 27 646 28 625 29 656 30 063 31 _ m minus } 19°221 30:000 Mean 1641 Final Nor- 1641 mal Varia- } ass tion u 12 13 1747 | 1-729 | 41-703 721 | -700 | -656 ‘617 | coz | -570 626 | +615 | +590 -c62 | -644 | -629 672 | -682 | -661 672 | 670 | -656 -706 | -694 | -667 -651 | -641 | -634 648 | -628 | +597 638 | -627 | -611 -660 | -636 | -618 612 | 607 | -591 676 | “651 | +620 664 | 640 | 698 -o51 | -622 | -606 -o67 | -654 | -626 672 | °653 | -623 648 | 638 | -626 644 | 626 | -604 607 | 595 | -591 [ 526 1 503 551 || “522 [ -485 565 | “560 | -551 597 | 588 | -564 ‘532 | 569 | +551 615 | -602 | -576 630 | ‘611 | -583 620 | 604 | +575 -654 | -626 | +594 516 | -501 [ Are [ 490 || 483 19-190 }18:731 | 18-057 1-640 | 1624 | 1-602 1640 | 1625 | 1602 a 592 "609 17583 1:586 1:586 15 16 17 18 1:663| 1639 | 1-640 | 1:636 [ 528 [ 524 ] [ 522 566 || 503 ||| -493 ||| “521 547| 531 |[ 521 J] °558 *568| 569 | +577 | 577 606| 600 | 592 | -595 618] 615 | -612 | -610 628| 620 | -622 “610 640) “651 | -649 633 585| -570 | -562 | -583 [ 508 547 || -442 }| 537 | -551 581| 575 | -571 568 574| 563 | -555 | 544 ‘572| 549 | +548 | +534 565| 570 | +519 | 550 590| 570 | +567 | -562 578| 571 | +567 563 576| 560 | “561 | “566 589| 580 | “581 578 600| 597 | +590 578 ‘575| 576 | ‘566 | ‘560 610| -576 | -528 533 537| 528 | +511 | -482 533| 526 | ‘515 510 539| 535 | 531 | -528 521| ‘516 | -51g | 524 548| 551 | 548 | -545 529| +533 | ‘528 | 530 557| 563 | 556 | -543 560| 550 | 549 | -559 -487| 489 | -494 | 490 17-189 | 16818 | 16-728 | 16-721 1:573| 1°561 | 1:558 | 1:557 1:573| 1:563 | 1559 | 1:557 Increasing ordinates indicate increasing horizontal force. 19 542 “545 559 *D76 hae, eee : _ ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 91 _ Hourly Abstract of Tabulations (in Inches) of Horizontal Force Magnetograph. SR oA i WP 1:570 [ 518 502 573 “580 582 592 590 613 m7 "543 *565 “559 527 “550 550 560 562 “574 "555 546 "537 16°574 1552 1583 "536 “566 “588 578 597 “597 “620 582 “553 569 16735 1558 1558 575 557 “556 “569 567 “570 16°770 1559 1559 an | 1593 | 1-604 572| °573 582| 586 581| “581 598] -601 598| “601 598| °595 594| -615 595 | 596 *564| +568 “560| “562 586 | “612 -550| -540 *553| “554 563| “564 672| “571 567| 566 ‘564| “569 B63 | “575 ‘573| 564 522| “524 518| -511 517| 521 521| °526 525| “534 557| *558 539| °535 551| “556 543| “516 512| “519 5 | 6 1-606 | 1-622 568] 572 588] 579 590| +589 597| -600 605] -611 602} -610 609} -602 623| 638 560| 575 563| “571 620] “574 534 544 B51] °555 566} °570 B71] °572 + *569| *576 574] -576 565 | “584 565| “585 538 | °553 B11] -520 534| +542 533| 541 530| 549 563| -576 541) +555 560| 580 536| 520 526| 532 TI \ 8 1-647 | 1-673 585| 592 575| +595 600| -619 *605| -623 622| -631 622| -644 606| -610 647| -616 597| -617 596 | °624 588] -631 576| -612 576| °603 588| -620 589| -610 602| +629 591| “624 598| -618 591| -600 575| °578 526] -541 551| -554 555| 588 568| 579 597| 617 5T1| +582 605] 637 *528| 561 541| +552 Sum Minus 24-000 Mean Means for beginning and end of the month 15°3 32 13°888 13°814 14161 14°547 14'880 14892 15167 14502 13°633 14:031 14191 13-522 13810 14:037 14046] 14:151 14265 14153 13°954 13°429 12°474 12°837 137126 13089 13°573 13°318 13°700 13-404 12°244 1 2 1:583 | 1593 *560| *600 *584| °580 *588| 589 *589| 594 “597 | *b97 *602| *602 *599| +598 587 | °586 439| *548 *564| ‘561 593 | *587 536 | *548 *546| *546 563 | *564 *570| +570 569 | *567 “571 | *567 “566 | *572 *570| *558 504] *511 *513| *522 *522| +518 524] +523 “533 | *525 539 | +543 *534| *535 546 | +546 *530| *542 “007 | *509 16°728 |16°801 1558 | 1560 1:558 | 1:560 16°831 |16°897 1561 | 1563 1561) 1563 16'998] 17°173)17'618 1:567 | 1-572 1:567 | 1572 1:587| 1°606 1°587 | 1-606 18'180)18°738 1:625 1°625 416170 13°873 —'096= progressive increase in the month 92 REPORT—1 886. Taste A (continued forwards).—Government Observatory, Bombay, Month Horizontal at 1 1565 | 1568 | 1555 | 1533 | 1518 | 1514 | 1500 | 1486 | 1:485 | 1:502 |] 1499] 1-498 2 “586 “596 567 539 “526 “500 “497 “491 486 “493 “477 "488 3 581 "592 "624 *605 553 *496 “470 "485 “510 “dll “516 518 4 “589 “595 593 567 *D47 533 627 522 “1d “514 “O10 “514 5 573 683 “564 b41 520 513 516 618 *520 520 518 “519 6 “602 “604 “599 “579 562 “553 “573 568 “576 550 509 "504 7 "569 “560 525 01 “474 “496 “480 *450 *460 480 473 “457 8 “570 "568 b51 526 "521 "509 “494 “489 *489 “486 “480 480 9 515 “517 516 627 526 “521 ‘O11 “505 488 487 “496 “497 10 523 514 514 499 “497 “497 501 “500 501 512 “505 503 11 515 B15 622 500 “497 481 489 "494 “489 481 485 *488 12 542 540 530 626 513 504 “503 502 “495 487 485 479 13 564 “560 *bd1 *b41 530 529 513 520 “508 “B01 “495 “488 14 “540 537 612 483 473 “470 460 “457 "469 462 "456 463 Taste B.—Government Observatory, Bombay, Month of November, Horizontal Force There are in the forms two columns for each hour; in the second are entered the 29-day sum (above), and the 29-day mean (below) for a given day ; the first are checked by actual summation at the beginning and middle of each month, and these figures are entered in ink; the rest are entered in pencil only. In the first column are entered the number to be added to the 29-day sum of the preceding day and the number to be subtracted from it to obtain the 29-day sum of the day of the entries, and also the excess of the first entry over the second with its proper sign. Bombay Civil 10 11 12 13 14 15 16 17 18 19 20 21 Hour Date 1 695 |-700 | 687 | °665 | -645 | 626 | 614 | -611 | -610 | -606 | -602 | -602 2 ‘691 | 696 | 682 | -660 | 641 | -622 | -610 | 607 | -606 | -602 |-598 |-598 3 689 | 693 | °679 | -657 |-638 |-619 | -605 | -602 | -602 | -597 | -594 | 594 4 686 |°689 | 675 | -653 | -633 |-615 | 602 |-599 | 598 | -594 |-590 |-590 5 680 | 684 |:670 | 649 | 629 |-611 |°598 |-595 |-595 | -590 |-586 | -586 6 676 | 679 | 666 | -645 |-625 |-607 |°595 | 591 |-591 |-586 |-582 | +582 7 ‘671 | 674 |-661 | -640 | -622 | -604 |-591 | -586 | -586 | 582 | -578 |-579 8 664 | 667 |°654 |-633 |-616 | 599 |-586 | °581 |-°579 | -576 1-573 |-574 9 658 |°661 | 647 |-627 |-611 |-596 | 582 |-576 |-575 |-572 |-569 | -572 10 “653 |°657 | °643 | -623 |-607 |°592 |-578 | -572 |-571 |-570 |-568 |-570 11 650 | 653 | 639 |-619 |-603 |°588 | -576 |°571 |-570 |-568 | -567 | -567 12 647 | 649 | °635 |°615 |°599 | 585 |-573 | 568 | -567 | -566 | -564 |-565 13 645 | 646 | 633 |-611 |-595 |-582 |-571 |-566 |-565 | 563 | -561 | -562 14 643 | 644 | 630 |-609 | 592 1-579 | °569 | -563 | -562 | -560 |°559 | -559 15 “643 |°644 | -629 |-607 |°590 |°576 | -566 | 561 |-560 |°558 |-556 | -556 16 *637 | 636 | -621 |-599 | -583 |°570 |-561 |-556 |-555 | -553 | -552 | -553 17 “632 |-631 |:616 |°595 |-579 |-568 |°560 | -°555 |-553 |-551 |-551 | 553 18 “631 |°630 | 615 |°594 |-578 |°566 | °559 | °553 | -551 |-550 | 549 | -549 19 629 | °629 |°615 |-594 |-578 | -564 | -555 |-550 1-549 | -547 | 547 | -547 20 "627 |°627 | 613 |:592 |°575 |-561 | -553 |-548 |-546 1-545 | 544 | -545 ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 93. of December, 1875. Hourly Abstract of Tabulations (in Inches) of Force Magnetograph. 22 23 0 1 2 3 4 5 6 7 8 9 Sum Mean | 1503 | 1:507 } 1-512 | 1512 | 1°502 | 1-499 | 1504 | 1508 | 1517 | 1-536 | 1554 | 1525 -490 | -500 | 501 | *501 | *503 | 504 | *503 | *507 | - *D3e - “515 | +517 | °539 | °522 | °509 | °513 | 510 | *515 | °521 | °529 | *547 | °566 “Bll | +514 | 510 | ‘508 | *507} °508 | *509 | °513 | °518 | “527 | *543 | °555 *518 | +516 | °515 | 516 | *518 | °522 | 525 | °532 | °541 | “563 | °589 | 592 “467 | -451 | +444 | *444 | 490] 479 | °474 | *486 | °499 | °530 | ‘546 | “561 484 | -477 | -469 | -478 | ‘481 | °485 | 490 | *494 | °498 | 516 | ‘540 | °559 483 | -486 | -489 | -483 | 483 | -480} 506 | *503 | °505 | ‘508 | *510 |} °518 +497 | 504 | +504 | 503 | -496 | °493 | “487 | 501 | *509 | °504 | *521 | °519 +493 | -498 | -489 | 487 | 479 | °479 | °486 | 494 | °509 | °520 | 520] ‘514 ‘477 | °479 | -480 | -483 | -487 | “492 | 489 | -493 | °500 | ‘515 | °533 | ‘544 “487 | -492 | -491 | 491 | -492} -492 | 492] -498 | ‘506 | °532 | °553 | *557 495 | -490 | -480 | -493 | -479 | °470 | *468 | °476 | °486 | 500 | *520,) *540 463 | -463 | -469 | -465 | “466 | “464 | “471 | *481 | *500 | °520 | *540 | °556 Pl a Tei sire [Ral apo Heth TL Te a a nea) 1875. Hourly Determinations of 29-day Means of each Hour. Magnetograph. The actual operation is to add this excess to the 29-day sum of the pre- ceding day, and enter the result as the 29-day sum of the day of the entries. The 29-day sums are divided by 29 by means of a table of products of 29 into all the integers from 1 to 999, and the quotients are entered below as the 29-day means. The integer ] in each number of Table A is thrown out of account in the construction of Table B, and this is kept in mind in taking the differences of Table C. Bombay Civil 22 23 0 1 Z 3 4 5 6 7 8 9 Hour Date 15 BBB | °560 |°561 |°559 | -562 |°563 | 565 |-568 | -574 | 589 | -608 | -627 16 B52 1-557 |°558 | -557 |°559 | 560 | 562 | -565 | 571 | -585 | -604 | 622 17 “B52 |-556 |-557 |°555 |-556 |°557 | -559 |-563 |-569 | -584 | -602 | -619 18 549 |-554 |-555 |-552 |-553 | 555 |-557 | -560 | ‘567 | 582 |-600 | -618 19 547 |-551 |-553 |-550 | -550 | 552 |°554 |-558 | -564 | -580 | 598 | -615 20 544 1-549 |-550 |-547 | °547 | 549 |°551 |°555 | -562 | 577 | 595 | 612 94 REPORT—1886. Taste B (continwed).—Government Observatory, Bombay, Month of Horizontal Force Bombay Civil 10 11 12 13 | 14 15 16 17 18 19 20 2i Hour Date 21 624 |-623 |-609 |°588 |°571 |°558 | 549 | -545 | -°543 | °542 | 542 | 543 22 “621 |°621 | 607 |°586 | 569 |°555 | 548 |°543 | -542 | 540 | -539 | -540 23 ‘617 |°616 |°601 | ‘580 | °562 |-550 | °542 |°536 |°536 |°535 | -534 | -534 24 -615 |-613 |°598 |-°576 | °559 |°548 | °539 | 533 |°532 | -532 | 5380 | 531 25 *610 | 609 | °594 | °574 | 557 |°547 | 540 |°532 | -530 |°531 | °529 | -529 26 -606 | °604 |°590 |°570 |°554 |°544 | °537 | 529 |-528 |:529 | -527 | -527 27 601 |°599 |°586 |°566 |-551 |-541 | -534 |-527 |-526 | 526 |-524 | -525 28 599 | 597 | 584 | °564 |°548 |°538 | 533 | 525 | 525 | -525 |°523 | 523 29 594 |°593 |°580 |°561 |°546 |°537 |°531 | 526 |-523 |:524 |-521 | -522 30 -591 | -589 |°576 |:556 | -542 |°533 | 527 |°522 |°520 |°521 |-b17 |-519 Taste C.—Government Observatory, Bombay, Month of November, 1875. Magnetograph SE 4 S Bombay n Civil LOD | Wale se 2 aS eee ea U7) 18) [5 Oh) C2 Be Hour AA fa, EateR | pent ot ye ere) tae ae 1 | 4 1 “145 | °147 | -142 | 138 | -139 | °137 | -125 | 129} -126 | -112) 098 | 092 5 2 ‘121 | 125 | 118 | 096 | ‘071 | -044 | 018 | 017 | -016 | 078 | -021 | -022 | 6 3 "025 | -024 | 028 | 013 | 029 | -028 | 026 | 019 | ‘056 | -027 | 059 | 092 ff 4 ‘058 | 037 | 040 | 037 | -028 | -053 | -067 | 078 | (079 | 082 | 075 | -081 8 5 ‘074 | 078 | 074 | 073 | -085 | 095 | -102 | °097 | -100 | “101 | -098 | -095 9 6 089 | 093 | °116 | 116 | 117 | *111 | °120} 121 | °119]-117 | 116] -109 10 if ‘098 | 098 | 109 | 116 | °120 | +124 | 129 | “136 | 124] -114 | 118} -105 11 8 "135 | °139 | -140 | °134 | +143 | +141 | -165 | “168 | 154 | -154 | -147 | +147 12 9 :076 | -090 | 094 | °107 | -108 | 089 | -088 | °106 | *108 | *101 | -108 | -103 13 10 ‘102 | -091 | 085 | 074 | -070 | 055 | 025 | ‘065 | 080 | -061 | 084 | 072 14 11 ‘084 | 085 | *088 | -092 | 081 | -093 | -099 | *100 | ‘098 | 096} 096 | 105 15 12 “114 | -111 | *101 | °103 | -096 | -089 | -090 | ‘087 | 077 | -084 | 086 | 079 16 13 ‘065 | -066 | 074 | ‘080 | ‘088 | 090 | -078 | ‘082 | 069 | -065 | 072 | 067 17 14 ‘143 | 132 | 121 | 111 | ‘089 | -086 | -101 | °056 | 088 | -082 | -082 | 079 18 15 ‘107 | °120 | 111 | °116 | 117 | +114 | -104 | 106 } +102 | 087 | -109 | -096 19 16 *125 | -115 | 101 | °107 | -109 | -108 | -110 | *111 | -108 | -106 | -108 | 106 20 17 *128 | 136 | °138 | 131 | 119 | -108 | 100 | °106 | -113 | -112} 113 | 113 21 18 "139 |"142 | -138 | ‘129 | 122 | 123 | -121 | 128 | -127 | 126 | 125 | +123 22 19 *122 | 119 | 123 | 132 | -131 | 136 | -142 | °140| +129 | -118]| -101 | -10L 23 20 "123 | 117 | °113 | °112 | 111 | -114 | -123 | 118 | -114|-114] -112]-109 24 21 "075 | ‘084 | 086 | 103 | 137 | +152 | -127 | 083 | 090 | 112 | -113 | 115 25 22 "023 | 030 |-019 | 017 | -056 | -082 | -080 | 068 | -040 | -062 | 071 | 076 26 (23 “050 | ‘049 | (059 | °071 | -087 | 083 | 084 | -079 | 074 | -079 | 081 | 095 27 24 076 | ‘084 | 090 | ‘088 | -080 | :091 | -096 | -098 | :096 | :100 | 104 | -102 28 25 083 | °073 | -075 | 077 | 074 | -074 | 076 | -086 | -094 | 108 | 113} +118 29 26 “111 | 111 | 112 | 106 | -096 | -104 | -114 | 119] -117 | -111 | -114}-113 30 27 "145 | °131 | -125 | °117 | -097 | 088 | 099 | -101 | 104 | -095 | :102 | 105 1 28 126 | °123 | °120} -111 | -116 | -119 | -130 | °131 | -118 | -122)-121 |-119 2 29 "162 |-161 | 146 | -133 | :125 | -123 | -119 | °123 | 136 | -135 | 127 | -117 3 30 072 | 027 | 025 | -027 | 044 | 054 | 062 | 072 | -070 | 064 | -064 | 091 ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 95 November 1875. Hourly Determinations of 29-day Means of each Hour. Magnetograph. Bombay Civil 22 23 0 at 2 3 4 5 6 7 8 9 ~ Hour Date 21 “B42 | 546 | 547 | 544 | 544 | °547 | 548 | 552 | -559 | 575 | 594 | -610 22 638 |°541 | °542 | *539 | 541 | -543 | 544 | °548 | 555 | 572 | 590 | -606 23 533 |°536 |°537 | 535 |-536 |-539 | -540 | 544 | -552 | 569 | -588 | 604 24 530 |°533 | 534 |-531 | °533 |°535 |°537 | -540 | 547 | -564 | -584 | -600 25 “528 | 531 |°533 | 530 |-531 | -532 | -534 | °538 | 545 | -561 | -581 | 596 26 526 | 529 | 530 | °527 |-528 | 530 | -531 | -536 |°543 |°558 | -577 | 592 27 523 |°526 | °527 | 523 |°525 | 526 | 527 | -531 | °540 | 555 | 574 | -588 28 “522 |°525 | -524 | -522 |-523 | -524 | 525 | 530 | 539 | 554 | 572 | 584 29 “520 | -522 |-521 | -520 |-521 | -521 1-522 | -528 | -637 | -551 | -569 | -582 30 ‘B17 | °519 | °518 | 517 |-517 | 518 | ‘519 | °525 | -534 |°549 | -566 | 578 Hourly Abstract of Differences from 29-day Means of Horizontal Force A-—B-+°100 Inch. | 22 23 0 1 2 3 4 5 6 7 8 ) 9 = i er dala Pe ee ee “070 | -078 | :067 | -075 | -082 | -082 | 090 | -090 | -104} -116 | -120 a4 7022 | -035 | ‘039 | -055 | :093 | -064 | ‘062 | -056 | -057 | -057 | -042 | -036 081 | -069 | -082 | ‘083 | 076 | 078 | -079 | ‘080 | -068 | :050 | 048 | -058 091 | -094 |} 083 | 090} -089 | -081 | ‘078 | -085 | -082 | -079 |-076 | -070 “097 | -088 | 093 | -095 | -097 | -101 | "101 | ‘096 | -096 | -086 | -083 | -086 ‘111 | 110} :109 | -106°} -104 | -104} -104 | -107 | °110 | -107 | 096 | -103 pub ELS. LUT, LUZ} .-114,}. -109,). -L03,) 209} 113) 2209) 113!) 112 141 | +141 | -134 119 | +115 110 | +129.) +122 | -110 | -100 | -085 | -073 ‘107 | ‘106 | ‘109 | ‘110 | -107 115 114 | *139 | +149 | -145 | -096 |-110 ‘075 | ‘080 | ‘064 | ‘065 | 071 | ‘087 | ‘089 | ‘078 | -089 | -097 | -099 | -086 099 | -098 | -093 | -093 | 088 | -087 | 086 | ‘084 | -088 | -099 | -109 | -108 096 | -104 | -104 | -125 | -117 | -115 | -138 | -144 | -092] -092 | -117 | -112 067 | -057 |} 109} ‘O71 |} -081 | ‘082 | ‘069 | -060 | -065 | -082 |-100 |-130 “092 | -092 | :093 | 083 | -081 | -087 | -085 | 079 | -077 | -082 |-091 | -093 095 | -091 | 095 | -104 | -102 | -100 |] 099} :098 | :096 | -099 | -112 |-120 “108 | 106 | ‘111 } *113 | -111 | -112} -109 | -106 | -101 | -104 |-106 |-117 SELOT | 108: | sTLORY <1T4 | att | 2L0)) 07s) HOG |) =107.) -118.)-127 |'-133 125 | +117 115 119 114 | -109 112 | -114 | -109 | -109 |-124 | -128 SLOS 3113) | “LLON) 116, |) -122,| “11i,) “Z| LOT.) -1205) -1185)-1207) 117 102 | -108 | 127} -123 | -111 | 124] 113 | 110] :123 | -114 |-105 |-100 095 | -153 | -054 | ‘060 | -067 | ‘075 | -076 | -086 | -094 | -100 | -084 | -063 073 | -069 | -071 | ‘074 | -081 | 075 | -067 | -063 | -065 | -054 | -051 | -059 ‘O88 | 084 | -095 | -087 | -082 |} -078 | -081 | -090 | -090 | -082 | -066 | -067 109 | -100 | :097 | -093 | :090 | 086 | ‘089 | -093 | -094 | -091 |-104 |-101 113 | -102 | -108 | :103 | -094 | 093 | :100} -092 | -104 | -107 |-098 | -102 AJA | 108 | -L09)) -112 | ALS | 127 | 227 | 127 | 133°) -139 |-140 | -142 gil | s110)) Obs; Wid ston) k13 | “108.| 10) a | AIG) |s108 17 120 | -118 | 122 124 | -123 | -127 | -131 | :130 | -141 | +151 |-165 |-164 ‘110 | -114} °126 110 | -121 122 | -094 | -108 | -083 | -077 | 092 | -068 088 | :081 | -088 | 090 | -092 | -094 | -100]} ‘101 | -098 | -092 | -086 | -084 96 REPORT—1886. Horizontal Force-Calculation of the Excess Solar-Diurnal Variation for 14 15 16 17 18 19 20 | 0967 1020 1113 1143 “1087 1027 1000 | 1010 “1010 “1050 1060 1017 ‘1017 1040 | 1003 1033 “1033 1127 1050 1053 1090 | 1043 “1030 1050 0893 “1020 0967 0987 *4023 “4093 4246 4223 “4174 “4064 “4117 1006 "1023 1061 “1056 1043 “1016 1029 | Horizontal Force-Calculation of the Luni-Solar 0911 “1006 ‘1917 “0988 1047 *2035 — 0118 — *0029 —"00012 —"00025 “1036 1061 2097 0968 0896 “1864 + 70233 0920 “1023 “1943 0963 “1055 “2018 — 0075 — *0019 —"00008 —"00021 0986 0981 “1967 1019 0927 1946 + *0021 + *0120}+ +0092)+ -0058}+ -0005 Days after 6 ee 10 ll 12 13 4 -0850/ -0893} -0960] 0960 15 1140] 1127! 1090! +1043 = 16 1037| +1023] +1013] —-1003 2 7 1380} 1330) 1217] “1117 Ss Sum 4407} °4373| 4280] -4123 Mean } -1104] 1093] 1070! +1031 Phase (0) . .| 1104) +1059/ +1052] -1006 | phase (4) . ‘1104! +1093} +1070] +1031 SUM. . 2208 2152 *2122 2037 Phase (2) . .| 0920! 0972! -1057| -1012 Phase (6) . .| 0937) 0940] -0977| -1031 Sum=(b) . .| °1857/ -1912| +2034] -2043 |a—b . . . .|+ *0351 + -0240/+ -0088|— -o006 a . . «|+ 0088 + -0060/+ -0022/— -0001 a-b » “| x0427. |+-00038 +-00026|+-00009] -00000 Variatn.= =f 36H) +°00025 +-00013 |—-00004 |—-00013 Phase (1) - -| +1121 1128] 1074] -1009 Phase (5) . -| +1138! 1112] -1057| -1090 | Sum=a’ ..| -2259 -9240/ -2131| 2099 Phase (3) - -| 0906 -0899| 0916) —-0939 Phase(7) . .| 0788 -0783| -0736| -0791 Sum=0’. . .| 1694-1682! -1652| +1730 | a’—v) . . «|4 +0565 + -0558|+ -0479|+ -0369 o . «|e 0141! + -0139 a! -b! | 1 | “0961 0978 1061 1056 *2022 "2034 0957 0962 1054 0990 2011 1952 + °0011/+ -0082 + *0003}+ °0020 +°00001 | +-00009 —"00012 | —-00004 “0922 “0922 0973 0979 "1895 “1901 “1028 1068 0915 0937 1943 “2005 — °0048)— -0104 — °0012|}— -0026 0990 "1043 *2033 1021 1033 "2054 — 0021 — *0005 —'00002 —"00015 0911 0983 1894 “1031 0875 “1906 — 0012 — *0003 x 0427. |+°00060 +:00059 | +-00051 | + -00039 | +-00025 | +--00002 |—-00005 | —-00011 |—-00001 1007 “1016 +2023 “0961 1076 *2037 — “0014 — *0003 —*00001 —"00014 “0964 “0883 1847 “1026 “0941 “1967 — 0120 — *0030 —'00013 Variatn.=fy.2(0) +00056 +-00055 |+*00047 | + 00035 | +-00021 |—-00002 | —-00009 |—-00015 |—-00005 |—-00017 | 1009 1041 “2000 + "0038 + 0009 +°00004 —00009 0889 “0889 1778 “1060 “0974 —'00031 * An ordinate of 1 inch corresponds to ‘0427 m.g.s. unit of force. —- the (Ath) Phase of a Lunation, i.e., for Full Moon. ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. Nov. 1875 to Jan. 1876. 97 21 22 23 0 1 2 3 4 5 6 7 8 9 0993] 0930] 0047] 0940] 0940] 0957; 0977} -0987! -0983| -1017! 1037! 1100} -1na7 1017] 1050] -1093/ -1090} +1133} -1130/ 1133] -1220| +1233) 1057] 1107} -t190} 1150 1063) 1060) 1007} 1140] 1030} 1023 0983] -0930/ -0907| -o047| +1033! 1137] -1343 0997] 1023) 1043] 1110] 1050} 1033} +1033} -1100/ -1080| 1110] «1290! 1937] «1277 4070] 4063) -4090) | -4280] -4153/ 4143, -4126] -4237/ -4203] 4131] -4397| -4ee4} 4887 toi} +1016} 1022! -1070! | -1038! 1036-1031! -1059| 1051] +1033} 1099! -1166] «1292 Diurnal Variations fe) and Tah): Nov. 1875 to Jan. 1876, 1008/1067) -1059| +1041) 1011] +1074) | -1072{ -1042| +1058) +1037 1089) +1157) -1161 W017} -1016} +1022} +1070] -1038| +1036} +1031 1059] -1051| +1033} 10991-1166 «1999 2025) 2083) -2081/ -2111| -2049| -2110/ -2103| | 2101! -2109/ -2070! | -2188| -2323| -2383 0977) -0941} +0903] -0046] -0947| -0991 0980) -o988] 1011} -o986| -o961| 0915! -o918 1020/0990] +1059] -1015] 1013] -0986] -0984] - 1002} -0990| -1020| -1002| -o945/ -o919 1997/1931] +1962) -1961/ “1960| 1977] | -1964] -1990] -2001| -2006| -1963| -1860| -1830 0028 |+ -0152]+ -0119|+ -0150/+ -0089)+ -0133/+ -0139|+ -o111/+4 -o108/+ -0064/+ -o225|4 -o4e3 |4 -0553 0007 |+ -0038]+ -0030/+ -0037|+ -0022/+ -0033|+ -0035 |+ -0028|+ -0027/+ -0016|/+ -oos6|+ -o116! + -o138 400003 | +00016 | +-00013 | +-00016 | +-00009 +-00014 | +-00015 | +-00012 | +-00012 | +-00007 | +-00024 | +-00050 | +-o0059 ="00010 |-+-00003/ -00000 | +-00003 | 00004 | +-00001 | +0002 |—-00001 | +-00001 |—-00006 | +-00011 | +-00037 |-+-00048 0894) 0887} -0902] +0951] -0973| -0999/ -0953] 0952] -0975| -o978| -0977| -0950| -oga7 0951) 0937} 1011] 0885] -0909| 0960] -1004) -0930] -ose2| -0887/ -0800} -0929 «0970 1845| -1824/ -1913| -1836| -1882| 1959] -1957| -1ss2] -1837| -1865| 1777! -1879| «1907 1034; 1058] +1068) -1049| 1028] 1001/0996] 1017] -1037| -1041| «1014! -0917| —-os90 0947] 0993] -0896) 0904] -0963] -0878] -0879| -o902] -o911} -0929/ 0952] -o927| -oga7 ‘I9s1] -2051/ -1964] +1953} -1991| -1879/ -1875| 1919] -1948| -1970| -1966} -1s44|agi7 136 |— -0227|— -0051|— -0117|— -0109 + -0080|+ -0082 |— -0037|— -0111/— -0105|— -o189|+ -0035/+ -o090 *0084|— -0057|— -0013/— -0029|— -0027/+ -0020|+ -0020|— -o009|— -o028|— -oo26!— -oo47|+ -oo09/ + -o029 =*00015 |—-00024 |—-00006 | —-00012 |—-00012 | +-00009 | +-00009 | —-00004 |—-00012 | —-00011 |—-00020 | +-00004 | + -00009 ="00019 |—-00028 |—-00010 | —-00016 |—-00016 | +-00005 | +-00005 | —-00008 |—-00016 | —-00015 |—-00024| -00000/| +-00005 1886. 98 REPORT— 1886. X. The Advantages to the Science of Terrestrial Magnetism to be obtained from an expedition to the region within the Antarctic Circle. By Staff Commander HBrrrick W. Creaxk, R.N., F.R.S. In Gauss’s paper on the general theory of magnetism, published in England in 1839, will be found the following conclusions :— (1) ‘It is clear that the knowledge of Y (or the component of the horizontal magnetic force directed towards the west) on the whole earth, combined with the knowledge of X (or the component of the horizontal force towards the north) at all points of a line running from one pole of the earth to the other, is sufficient for the foundation of the complete theory of the magnetism of the earth.’ (2) ‘Finally it is clear that the complete theory is also deducible from the simple knowledge of the value of Z (or the component of the magnetic force directed towards the centre of the earth) on the whole surface of the earth.’ Accepting these conclusions as thoroughly sound, and in no measure altered since they were written by other investigators, let us now inquire into the question how far are we prepared by observation of the earth’s magnetism for a calculation of this kind. Thanks to the activity of observers in many lands and over many seas during the years 1865-85, we have been supplied with the necessary observations, which have been utilised for compiling charts on a large scale of the normal values of the declination, horizontal force, and vertical force for the epoch 1880 from which the values of X, Y, Z may readily be obtained for a large portion of the earth’s surface. These elements for the zone contained between the parallels of 60° N. and 50° S. are (except for some portions of Northern Asia and Central Africa) accurate; from 60° to 70° north latitude and 50° to 60° south latitude they are less accurate. North of the parallel of 70° N. and south of 60° S. are two portions of the earth of which our knowledge is far more limited ; but whilst we have had comparatively recent observations in Arctic regions, nearly the whole of the Antarctic regions have re- mained unvisited for magnetic purposes since the memorable survey conducted by the late Sir James Ross in 1840-43, so that the charts are correspondingly weak in those latitudes. A reference to the accompanying map shows that the Challenger, whilst on her voyage from the Cape of Good Hope to Melbourne, crossed the Antarctic circle about the meridian of 79° HE. The magnetic observa- tions during that period combined with those made at Sandy Point, Magellan Strait, since 1868, and some declination observations recently made in the South Pacific between New Zealand and Cape Horn in lati- tudes between 50° and 60° S. give ample evidence that considerable change of the magnetic elements has occurred since Ross’s voyage. Of the extent of these changes our information is so limited that the old survey is of but little use in enabling us to complete the charts of 1880 with the requisite amount of accuracy, and therefore the X, Y, Z required for Gauss’s method of theoretical investigation are still wanting. Although it is true that Gauss has shown the method by which mathematicians may, from an accurate knowledge of the magnetic ele- ments over an extended area in both hemispheres, calculate, nearly, those of the remaining portions, yet supposing this to have been done—and it Bri 56" Feport ANTARCTIC MAGNETIC SURVEY, Epoch 1840-1845. Suclination. found ECD Br, Ob serValtons. Befa 2 Boe sere ined ) i in 8 rth, ntal le of plete cible the hole sare jnire s y of * f the from rtion > N. otral south south is far tions re re- arvey ts are enger, rossed. serva- Point, cently p lati- hange an ol th the for HA ste . “ai © PLL : Se i oe RSS Die SRE YY y SS 5S sata roe ae SURVEY, Southerly larat of observations since Hoss Voyage, aud Antarctic Survey, 1BVOVS, 0 § on Southerly tirat of Ross's Voyage, and Antarctic Survey, 1840-45. — af = z : Mlustrating keport on the best means of Comparing & Keducing Magnetic Observations. ON COMPARING AND REDUCING MAGNETIC OBSERVATIONS. 99 is a work of considerable labour—the results would hardly be accepted as final until observation had done its work in every navigable sea and on every shore open to the explorer, in proof of the theoretical results. It has already been remarked that we know far more of the earth’s magnetism from observation in Arctic regions, where the approximate position of the north magnetic pole has been determined, than in the Antarctic regions where the position of the south magnetic pole is yet indeterminate. Thus it appears that great advantage to the science of terrestrial magnetism would be derived from a new magnetic survey of the southern hemisphere extending from the parallel of 40° 8. as far towards the geographical pole as possible. For carrying out such a survey we have many advantages over our predecessors in the Hrebus and Terror, besides the benefit of their experience. At Melbourne there is a magnetic observatory equipped with all the most modern apparatus which would form an admirable base sta- tion, whilst subsidiary base stations might be formed at the Cape Observa- tory, and Sandy Point, Magellan Strait, for the use of the portable abso- lute instruments. The survey, too, must in a great measure again be carried out on board ship at sea, and here we have a powerful aid in steam which would enable an observer in calms and moderate weather to obtain excellent results by the process of swinging the ship. The observations at sea might be accompanied with considerable advantage by observations made with the portable absolute instruments on ice as frequently as pos- sible. Ice is specially mentioned as being free from the local magnetic disturbance which is common in islands and on rocky shores of igneous formation. But the valuable aid of steam, which enables the seaman and observer to handle his vessel with ease and precision, involves a large increase of iron in the ship in the form of engines, boilers, &c., and a corresponding increase of trouble to the magnetician. Those who have read Sabine’s detailed account of the errors of the compass, due to iron in the ships Hrebus and Terror, will have found that the deviation of 3° or 4° in the compass at Hobart Town, became 50° in the high southern latitudes, which must have all but annihilated the earth’s directive force on certain courses and rendered the compass useless. Experience derived from the magnetic results of H.M.S. Challenger and other ships of the Royal Navy points to a means of avoiding much of this difficulty, as well as to the selection of a suitable vessel, and above all to a proper position on board—considered magnetically—for the instruments. The importance of this latter point will be appreciated when it is remembered that the errors of the observed magnetic elements ‘due to the direction of the ship’s head can generally be eliminated by swinging the ship, whilst those proceeding from vertical magnetic forces -are constant for every direction of the ship’s head when upright—variable when she is inclined at different angles of heel, and requiring frequent references to a base station to ascertain their amount. On all accounts, therefore, it is necessary that directly a vessel is ‘selected for a magnetic survey, positions for the compasses and relative magnetic instruments used at sea should be determined after careful experiment, and all iron within 30 feet of them removed if possible. Subject to these precautions, a magnetic survey of the Antarctic seas might be made with satisfactory precision and great advantage to the science of terrestrial magnetism. H2 1ec0 REPORT—1886. First Report on our Experimental Knowledge of the Properties of Matter with respect to Volume, Pressure, Temperature, and Specific Heat. By P. T. Man, M.A. ; Relation of Pressure to Volume ; Gases—Regnault’s Investigations, and General Results. Brrore Regnault published his ‘Mémoires’ attempts had been made without success to detect deviations from the relation of pressure to- volume required by Boyle’s law. In his sixth mémoire' of tome xxi. Regnault describes in detail his arrangement for testing the accuracy of Boyle’s law for atmospheric air, and for the gases nitrogen, carbon dioxide, and hydrogen. Ata large number of pressures ranging from. that of a single atmosphere to that of about thirty atmospheres experi- ments were made of the following kind: a manometer, at the middle of which was etched a mark which divided it into (almost) exactly equal volumes, as known by the weights of its contents of mercury, was filled at a given exactly known temperature and pressure with atmo- spheric air, or the gas to be examined ; the pressure was then increased until the mercury was forced up to the manometer tube, so that the top of the meniscus was seen, by the cathetometer, to be just touched by the mark on the middle of the manometer tube, the length of which was about 3 metres; the pressure was then again recorded, and the ratio of the former to the latter pressure calculated. If in all cases Boyle’s law applied with accuracy the ratio would always be 2 to 1. But it was. found for the gases mentioned that this was never accurately the case, and that the deviation from this ratio was greater the greater the origi- nal pressure, and that air and nitrogen under these conditions up to 30 atmospheres were always more compressible than Boyle’s law required, but that for hydrogen the compressibility was always Jess than Boyle’s law required, and that the deviations from Boyle’s law were always greater the greater the original pressure up to 30 atmos. For example, in the case of nitrogen the ratio of vp for, the original and for the doubled pressure (which should be 1, if Boyle’s law applied. exactly) was 1:001012 for original pressure 753°96 mm. and 1006784 3 Ene 10978:20'-);; the temperature being constant (4° to 5°) in each case, Again, for carbon diowide the ratio was at 3:08° 1:007597 for original pressure 76403 mm. and, at 2°7° 1:153681 7 $3 9612°39 ,, But for hydrogen the ratio was at 44° 0:998584 for original pressure, 969°19 mm. and, at 8°95° 0°9944.60 i 43 1183-08 ,, Tu all three cases we notice that the deviation from Boyle’s law is greater the greater the pressure ; the deviation is much greater for carbon dioxide than for the other two gases ; for hydrogen the compressibility is less, for the others greater, than if Boyle’s law were accurate. These: 1 Mémoires de VAcadémie, t. XXis EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 101 results of Regnault’s work have been confirmed by his successors within ° the same range of pressure. In tome xxvi. of the Mémoires, Regnault, in the third part of the first mémoire of the volume, determines the variations of vp for pressures from about one atmo up to not more than eight atmos for atmospheric air and for carbon dioxide again; and for oxygen, nitrous oxide, nitric oxide, carbon monoxide, marsh-gas, cyanogen, ammonia, hydrochloric acid, hydrogen sulphide, sulphur dioxide. The variations of vp for atmospheric air and for carbon dioxide agreed very well with the values obtained up to 8 atmos in the former set of experiments; and this agree- ment is a guarantee of the general accuracy of the results for the other gases, the gas in each case being tested and found pure and experimented on at some fixed temperature lower than 10°. The deviations from Boyle’s law were in all these cases found to be in direction of greater compressibility. It should be mentioned that the dates of publication of these two sets of mémoires of Regnault were 1847 and 1862. , The volumes, in each case, occupied by the gas at different pressures were known by the weight of mercury corresponding to the part of the manometer-tube occupied by the gas, and the pressure by the vertical height of mercury supported by the gas, this height being corrected for standard pressure and density of mercury: for Regnault found by special experiments that mercury is compressible, and the density which at 0° is 13°596 is at higher temperatures less, according to the rate of absolute expansion of mercury. The results of these investigations are given in the fifth and seventh mémoires of tome xxi.; at p. 328 there is a list of absolute dilatations of mercury between 0° and T°, where T is 10°, 20°, or any multiple of 10° up to 350°; the total dilatation for 0° to 10° being ‘001792 for 1 volume at 0° O° ,, 390° ,, 065743 be “I and the compressibility of mercury per atmosphere was investigated and found (p. 462) to be 00000352, and for this corrections have to be applied throughont the height of the column of mercury. It will be noticed how- ever that for pressures of not more than 30 atmospheres the correction due to this is inappreciable, and will in fact be drowned in inevitable or unavoided sources of error, The constant temperature of the gas in the , manometer was always secured by surrounding it with a jacket through which a current of water of constant temperature was passing constantly. Regnault, as Debray pointed out (see Ditte’s ‘ Propriétés générales des corps,’ p. 17), omitted from his calculations the weight of the com- pressed gas in the manometer, which being added increases the apparent pressure of the gas, the increase in Regnault’s tables being due to the weight of a column of about 2 metres of the gas: a small correction is due to Regnault’s numbers on this account. Among the data required for the determination of the values of pv mention must not be omitted of the atmospheric pressure which must be reckoned and added to the pressure of the column of mercury. This outline must suffice to give some notion of the precautions taken to avoid error, and the pains taken to secure an accurate determina- tion of all the data required in these investigations, in which Regnault obtained for many gases up to eight atmospheres, and for a few up to thirty, the actual relations of pressure and volume, and the extent to 102 REPORT—1886. which in each gas Boyle’s law is found to be, though approximately true for small variations of pressure, deviated from more and more as the pressure is increased (‘ Mémoires de ]’Académie,’ t. xxvi.). Some of the gases which Regnault selected were liquefied at the temperature of the experiment by pressure alone, and in these cases it was noticed that drops of liquid condensed on the mercury and on the glass, and that while this was taking place quite a considerable diminu- tion of volume was brought about by a small and gradual increase of pressure (p. 261). The liquefaction of these gases—viz., H,S, SO., C.N2, NH;, CO,, and of chlorine and hydrogen chloride—was known, having been effected by Faraday many years before.! Andrews has shown? that a body in the gaseous state may be brought to the liquid state by a continuous process, in which it is im- possible to notice any precise point at which the gas becomes liquid, the deviations from Boyle’s law, which are hardly noticeable at first, being gradually increased till the relation between pressure and volume is not even approximately represented by this'law, the gas becoming on still continued pressure less and less compressible, so as to finally be undistinguishable in this respect from a liquid. It was thus shown incidentally in the course of Andrews’ experiments that for high pres- sures the gases examined became less compressible the greater the pressure, a phenomenon which was observed by Regnault for hydrogen only, but not for the other gases at the pressures to which he subjected them, i.e. up to 30 atmospheres. Before Andrews, Natterer had made experiments extending over a long time—his published papers dating from 1844 to 1856—with the Object of liquefying and solidifying gases by great pressures, and he found that up to 2790 atmospheres the gases hydrogen, oxygen, nitrogen, nitric oxide, as well as atmospheric air, beyond 100 atmospheres, were all notably less compressible than Boyle’s law required.?-> The general result of the effect of pressure on volume in the case of gases at ordinary tem- peratures as given by Regnault and by Natterer made it desirable to in- vestigate this relation with all the accuracy attainable for a range of pressures much greater than Regnault had been able to measure with sufficient accuracy. Amagat’s Investigations on Relation of Pressure to Volume in Gases. Amagat in the year 1880 published a paper, the first of a series, in which he examined air, hydrogen, oxygen, carbon monoxide, marsh-gas, and ethylene as to their behaviour at given temperature at various pres- sures up to 400 atmospheres or beyond.® In these investigations Amagat obtained his greatest pressures by the height of a column of mercury in narrow flexible steel tubes attached to the side of a shaft of a mine of some hundreds of metres in depth. 1 Phil. Trans. 1823, pp. 160, 189. 2 Phil. Trans. 1869, Part IT. p. 575. 3 Poggendorff’s Annalen, lxii. 1844, p. 132, and Liebig’s Am. liv. 1845 p. 254. 4 Sitzungsberichte der haiserlichen Akademie der Wissenschaften zu Wien, v. 1850, p. 351; vii. 1851, p. 557; xii. 1854, p. 199. 5 Pogeendorfi’s Annalen, xciv. 1855, p. 436. 6 Annales de Chimie et de Physique, 1880 (5), xix. p. 345; 1881 (5), xxii. p. 353; 1883 (5), xxviii. pp. 456, 480, 501. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 103 The principle of the measurement of pressures was the same, therefore, as that used by Regnault. Various devices have been used by Cailletet for applying and measur- ing increased pressures; and Amagat suggests a plan which might be adopted, and by which the experiments might be extended to vastly in- creased pressures—namely, having, e.g., determined the law of compres- sibility by a vertical height of 76 metres of mercury up to 100 atmos pressure, we may extend it up to 200 atmos by exerting on the top of the column pressures up to 100 atmos. But Amagat prefers the direct method, and applies it up to 430 atmos; though for the purpose of ex- tending the results to still higher pressures he has! all the apparatus necessary. One most striking fact which results from Amagat’s observations—and it is so uniformly true for the gases which he used and for all the tempera- tures at which he experimented, and whether the gas was or was not liquefied in the course of compression, that it has the appearance of being a natural law—is that for each gas beyond a certain pressure the law of compressibility is more and more nearly represented by the equation — p (ve) =, where a and 6 are constant for a given substance at a given temperature ; and a varies but slightly for the same substances at different tempera- tures. The curves by which the results are represented ? have for abscissz the values of p in metres, and for ordinates the values of pv; and for above 180 metres the curve becomes almost straight. In the case of the gases liquefied (as, e.g., CO, at 18°, one of the tem- peratures of the experiments), as also of gases which, though not lique- fied, were compressed near their critical points (e.g., ethylene), the only regular part of the curve is that at high pressure, which is nearly straight. For hydrogen the relation between pv and p is represented on the diagram by a straight line for all except the very lowest pressures. The temperatures for which Amagat obtained curves of relation of vp to p were temperatures at intervals between about 15° and 100°, giving from 4. to 10 curves for each gas. So far we have said nothing of experiments made as to relation of volume to pressure where the pressures are less than 760 mm., and espe- cially when they are very small. Special investigations with this object were undertaken by Siljestr6m (‘ Pog. Ann.’ 1874) ; by Mendeleeff with others (‘ Ann. Chim.’ (5) ii. 1874, and (5) ix. 1876; also ‘ Nature,’ x. 1876-7) ; and by Amagat (‘ Ann. Chim.’ (5) viii. 1876 ; and (5) xxviii. 1883). Ezperiments on Relation between Pressure and Volume of Gases at Pressures below 1 Atmo. Mendeleeff and Siljestrém come to the conclusion that for small pres- sures the compressibility is less than Boyle’s law requires, and that the limiting condition of a gas is that in which the density is nil and the pressure finite (‘ Ann. de Chim. et de Phys.’ 5, xxviii. p. 482). 1 Annales de Chimie et de Physique (5), xix. 1880, p. 348. 2 Ibid. (5), 1881, p. 22 104 REPORT—1886, Amayat, on the other hand, finds the deviations from Boyle’s law at low pressures sometimes positive, sometimes negative, and all within the limits of error of obseryation—in other words, he does not detect any deviations from Boyle’s law for initial pressures under 370 mm. ; any such deviations, if they occur, being unrecognisable at such small pressures. There is, Amagat says,! no appearance of any sudden change in the law of compressibility of gases at the smallest pressures to which they have been submitted; it is therefore, he says, well to continue to apply Boyle’s law to gases down to pressures of a few millimetres. As to the cause of difference between his own results and those of Siljestrom and Mendeleeff he suggests that—at least for Mendeleeff—the method of experimenting was favourable to giving prominence to a source of constant error, such as a slight defect in the barometric vacuum, . 497, In 1884 Krajewitsch ? attacked this question of compressibility of air at small pressures, from 11°64 to 0:28 mm., with the general conclusion that the compressibility diminishes with increasing pressure up to 11°64 mm.; and he remarks that though his results are not accurate quantita- tively, there is no doubt of the qualitative result-as substantiating the conclusion he draws. The following results of observation are given in his paper :— mm. For p=11-636 he finds pv =108 ” 8385 ” » 96 rt aapllaleyeey 4 5 ee 99 2646 ,, 39 58 % E947 5, rp 46 and so on down to p G28. . 6 And he states, among other conclusions which he deduces, this, that at any given temperature air has a certain minimum density below which it loses its elasticity, this minimum density probably increasing with fall of temperature. Volumes of Oxygen Gas at Low Pressures (Bohr). Again, Bohr * has endeavoured to solve the question for the case of oxygen; and his conclusions agree in the main with those of Mendeleeff and others, while he finds, if his results are to be relied upon, a remark- able point at a certain small pressure which we will speak of after briefly describing his general method of procedure. Without describing the apparatus in detail, it may be enough to state that the tube containing a bubble or two of perfectly dry and pure oxygen was arranged vertically side by side with a thoroughly dry barometer- tube, very completely exhausted of air, each of these two tubes standing in mercury in a separate limb of a U-tube; and that the U-tube, by means of a stop-cock at its lowest point, could be brought into communi- 1 Annales de Chimie et de Physique (5), 1883, xxviii. p, 499. 2 Beiblatter, 1885, ix. v. p. 315. 3 Wiedemann’s Annalen der Physik und Chemie, 1886, iii. p. 459, EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 105 cation with a reservoir of mercury which had been thoroughly heated and dried, while the reservoir could be adjusted vertically so as to alter the level of the mercury in the open limbs of the U-tube and therefore to raise or lower the top of the column of mercury in the barometer-tubes. ‘One of the barometer-tubes was used as a barometer for comparison with the other by a cathetometer ; the other was graduated and served for the introduction of oxygen. It will be noticed that by the arrangement described above the pressure of the same quantity of oxygen could be increased or diminished at will by raising or lowering the reservoir of mercury. After the introduction of the oxygen its volume in ce. is read and the pressure in mm. of mercury at a constant temperature. Several readings were taken at intervals of about an hour generally. No pres- sure was finally read off after an interval of less than two hours, and often the readings for a single pressure and volume were taken at inter- vals of from twelve to twenty-four hours. Each result recorded is the mean of several observations extending over some time. Another series is then taken at the same temperature after introduction of a little more oxygen ; and perhaps still another. These give us data‘ for tracing a part of the curve, say from-p (abscissa) =0'12 mm. to p=7'45 m.; and pv (ordinate) =13°215, to pv=139°96 ; and so by other series of experiments Bohr extends the curve up to p=15-02 ; puv=311°83. The point which was alluded to above is at 0°70 mm. pressure, at which this volume is (between limits) indeterminate ; so that if the oxy- gen is at the fixed temperature of the experiment submitted to a pressure of very slightly less than 0°70 mm., and allowed to remain five or six hours, the volume (and the pv) will be considerably different from that which would be exerted by the oxygen after standing the same time at the same temperature at a pressure very slightly more than 0°70 mm.; thus on p. 472 (loc. cit.) for 0°70 mm. twenty-three observations gave as mean volume 47 cc., and twenty-five observations at same pressure gave 52°41 cc. The peculiarity at this point has been verified by Bohr by re- peated observations specially directed to it. As a confirmation of all these conclusions concordant results were obtained by using tubes of different internal diameter—one of 18°5 mm., the other of 32 mm. Thus Bohr finds, for representing relation of pv to p, for oxygen at pressures from 300 mm. downwards, a line very slightly convex and nearly parallel to the axis of abscisse for some distance, till from say 60 mm. to 0:70 mm. it curves down very considerably ; and again from 0°70 mm. onwards towards 0 mm. another curve which curves rapidly down so as to tend to become nearly vertical; this shorter part of the whole he calls the small branch, and the part from 0:7 mm. to some hundreds of mm. the long branch of the whole. The volumes of oxygen varied from about 20 ce. to 200 ce. in different experiments. The short branch of the curve he finds can be approximately repre- ‘sented by the formula (p+0:07)v=k ; and the long branch by (p+0°109)v=h’' ;sx where & (and also Z’) will be different numbers according to the amount -of oxygen present. 106 REPORT—1886. The pressure of Hg-vapour as determined by Hertz 1 aie SP. as 0:0005 mm., and at 20° is 0:0013 mm.; Bohr’s results recorded in his paper are for pressures of 0-1 mm. and upwards, and therefore could not be seriously affected by any error due to pressure of mercury vapour ; moreover, his measurements of pressure being in all cases differential with a mercury-barometer, this pressure would be almost if not entirely eliminated. The power which the inner surface of the glass tube may have in condensing the oxygen in the conditions of these experiments must not be disregarded wher such very small pressures are concerned ; it may be that the walls of the tube and the surface of the mercury are not wholly without action on the gas; if any action were exerted it might well be quite imperceptible in relation to pressures of, say, over 100mm.; any source of error which might be so trifling as to be ignored at higher pressures might be important at abnormally low pressures ; in these extreme cases the relation of pressure to volume as observed may possibly be not wholly determined by the molecules of oxygen, but may be partly influenced by the surface of the glass or of the mercury; cf. Amagat (‘ Ann. de Chim. et de Phys.’ 5, xxviii. p. 499). It must be allowed that Bohr has gone a long way to meet any doubt on this head by using two tubes of very different diameters; but further experiments with still wider tubes, and with tubes of different varieties of glass, would probably show whether the surface of the glass in contact with the oxygen is in any way concerned. Some remarks of Regnault? in reference to Dalton’s law of the mixture of gases with vapours as a ‘ theoretical law,’ and showing devia- tions from it, due to the inner surface of the glass, are suggestive of such an influence in other cases by analogy. Certainly, on the face of them, the observations of Bohr are remark- able, and his singular point difficult to account for in any other way than the direct and obvious one; and his experiments show the greatest pains taken to minimise the effects of the possible sources of error. Volume and Temperature—Regnault. Regnault determined the dilatation of dry air by many series of experiments and by different methods. _ Representing by 100a the whole expansion of unit volume of dry air at 760 mm. between 0° and 100°, his different series gave, taking the mean of the numerous determinations of each set— 1. 100a=:36623 with possible error ‘00140. 9. 100a="36633 ,, . » 00101. 3. 100a="36679 f , 00079. 4. 100a="36650 ,, i: , 700130. In the above experiments the dilatation was arrived at indirectly by observing the increased pressure of air at constant volume between 0° and 100°, and deducing by Boyle’s laws the volume which the air at 100° would then occupy. The mean of a fifth set of experiments, by which the value of 100a is- determined for expansion at constant pressure, gave— 5. 100a=°36706, with possible error -00025. 1 Wiedemann’s Annalen der Physik und Chemie, xvii. p. 199. 2 Mémoires de V Académie, t. xxvi. pp. 694, 695. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 107 The above are described in the first part of the first mémoire of Regnault in t. xxi. of the ‘Mémoires de l’Académie.’ Similar experi- ments were made (described in the second part of the same mémoire) with the following gases :— Gas Constant Volume Constant Pressure Hydrogen ; : 2) BEB EE is : : Atmospheric air. 6 : . 3670 Nitrogen : , i BGRR 04 ; eS Carbon monoxide . PS bomaae.. 2 . *3669 Carbon dioxide ‘ Bice ; . 3710 Nitrous oxide : BT oO 20k ; peels) Sulphur dioxide . BGHoet : . 3903 Cyanogen : : AVESSLD) 9-2 ; A a80d This difference in all cases between the expansion of volume at con- stant pressure, and the increase of pressure in constant volume, from 0° to 100°, is due to the fact that in none of the cases is Boyle’s law accurately true. But the numbers for constant volume and for constant pressure are very nearly equal for hydrogen, air, and carbon monoxide. In this mémoire it is shown for air at constant pressure (p. 99) that— 100a='3657 for 511 mm. °3648 ,, 149 mm., thus diminishing with diminishing presswie; also that the rate of expan- sion of air at increased pressures increases; thus (p. 110) for air at pressure 3655 mm.— 100a=°3709. From these and from results for gases other than air, given in this mémoire, Regnault infers that the differences in the coefficient of dila- tation of different gases are most striking for great pressures, and espe- cially if these are not far removed from those under which the gases can be liquefied, and that the deviations from the coefficient for air are smaller the smaller the pressures under which the gases are examined. The coefficient a for such gases as sulphurous and carbonic acid gases, for instance, diminishes very much more rapidly with diminishing pressure than the coefficient for air. Gay-Lussac’s law of the equal dilatation of gases with equal rise of temperature is therefore considered by Regnault as a ‘loi limite,’ which is approached more and more nearly by each gas the smaller the density and pressure at which its dilatation is observed. Volume and Temperature—Amagat. Amagat! tests air and hydrogen for compressibility at temperatures up to 320°, and finds that the ratio P ss , where v is very nearly 2 xv, is for air, 7 at. 0° , , = 11-0015, L000? : = COLE, 3 200° . . =1:00025, PA 3 ~ = O0CIS: ' Annales de Chimie et de Physique, 1873 (4), xxviii. p. 274. 108 REPORT—1886. at initial pressure of about 760 mm.; and for hydrogen the mean of a num- ber of experiments at 250° gave 099986, which is nearer to 1 than at ordinary temperatures; as are also the above values for air (omitting that for 0°); these being in fact distinguished from 1 by numbers of the order of experimental error. Now air was found to deviate from Boyle’s law in one direction and hydrogen in the other direction when submitted to pressures of a few atmospheres, and the effect of the results here given is to show that both these gases tend at higher temperatures to obey Boyle’s law more nearly than at lower. In ‘ Ann. Chim.’ [4] 1873, xxix. pp. 246-285, Amagat considers the rates of expansion with increasing temperature for SO,, CO,, NH, as well as for hydrogen and air, and gives (p. 261) the following results for aa? where v is nearly 2v’ for SO, and CO,; at about 700 mm. SO, CO. At 165° ; . 10185 At 8° ; . 1:0065 eee at eee OTTO ea CS ODE SE UOP or ay oe OOS Beles 9°. 1o0ee SG ns T0082 ate. One 200?) oal-O021 Comoe « » 10008 aU. ~ ip AAOOLS » 200° . . 1:0006 in which it is clearly seen how these gases also, as well as hydrogen and atmospheric air, approach nearer to agreement with Boyle’s law as temperature rises. On page 279 Amagat gives. a table of the coefficients of dilatation = for different gases at different temperatures ; this table also shows how nearly they approach to each other and to Gay-Lussac’s law in this respect. The following selections will exhibit this :— The value of = deduced from experiment. for SO, for CO, for SO, for CO, at 0° es 003724 at 100° 003750 ‘003695 =, plo 004010 ; », 200° 003695 ‘003685 5, wa? 003846 003704 », 250° 003685 ‘003682 uae 003792 003699 The conclusion to be drawn from these results is that gases approach more and more to conformity with Gay-Lussac’s law (as well as with Boyle’s law) the higher the temperature, so far as the experiments have been carried at ordinary pressures. Results at High Pressure—Amagat. But the very thorough investigation of Amagat already mentioned (p. 102)! shows the relation of pv to p beyond the pressures treated of hitherto in reference to Boyle’s and Gay-Lussac’s laws, curves being 1 Annales de Chimie et de Physique, 1881 (5), xxii. pp. 353-398. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 109: drawn expressing the results in reference to this relation for tempera- tures from 16° to 100°; and the pressures for each curve for each substance ranging from about 20, metres to 320 metres. The gases treated in this exhaustive manner are nitrogen, hydrogen, ethylene, carbon dioxide, and marsh-gas. With the exception of the curves for hydrogen, each curve was irre- gular, the relation of pv to p becoming regular only after the pressure was about 120 metres, or about 160 atmos, after which the result for any substance was expressed very approximately by the equation p (v—a)=)b; where § was different for different temperatures for any substance, and a was nearly constant for all the temperatures employed. In studying the effect of Amagat’s results in this paper in extending our knowledge of Boyle’s and Gay-Lussac’s laws, it must be remembered that the tempera- tures were necessarily very restricted, being not over 100°, while the pressures were very great. But the facts brought into notice by com- paring curves for the same substance for different temperatures are im- portant; we will be content with indicating one or two of these. At high pressures, for all the gases studied, the values of pv at any given temperature increase continually with the pressure, and are repre- sented by an almost absolutely straight line for the increasing abscissz p, so that if p’ and v’ are higher pressure and corresponding volume yt P® 51; that is, the gas in this condition is less compressible than if v p Boyle’s law were exact. The question arises, does this deviation increase or diminish as temperature rises? The case of any gas will do to try this. Taking the case of hydrogen, we extract the following data (p. 378 loc. cit.) : if was) is the ratio for hydrogen at 100m. and 320m. pressures, this ratio is Bee Lain eeresy: 0°830 at 60-42 fast ois 06883 AOE oss). 4. 7.0838 sds Ws dee tas he A ex B56 whence we see that for higher and higher temperatures the ratio -approaches more and more nearly to 1, or the gas deviates less and less from Boyle’s law. But this approximation does not imply that Boyle’s law is even a theoretical condition for these very high presswres at much higher temperatures ; for a may approximate more and more, as tempera- twre rises, to some value, for. each gas, less than 1. Dilatation of Gases at very High Pressures. To find for high pressures the dilatation of gases, we must find v’—v 9 U . . by finding PY and ”” | or the ratio of the ordinate to the abscissa at two temperatures ¢ and ¢’, the pressure being the same in both cases, so that we have the dilatation at constant pressure. We give an extract from a table ' which illustrates this for hydrogen, and therefore, for other gases, at very high pressures; the table gives the whole dilatation for the temperature-range stated; the coefficient may be deduced by dividing by the temperature-range in each case. ' Annales de Chimie et de Physique [5], 1881, xxii. p. 382. 110 REPORT—1886. 17°—602 60°—100° Pressure 40 metres . : 7220;0035: . ; : . 0:0029 Lr WhO as ; . eO-0083 01. ; . 0:0028 ae ea a; ‘ - S 0008. ; ; . 0:0027 *- -060e is é : 2 00030" : . 0:0025 B aos. P : . 00028 . ; . 0:0024 It will be noticed, on calculating the coefficients of dilatation, how very much they differ, in this condition of very high pressure of the sub- stance, from the coefficients at ordinary pressures ; it will be seen also that the coefficients of dilatation for 1° are smaller, at same pressure, for higher than for lower temperatures. In the equation p (v—a)=b for the straight portions of the line—for high pressures—if p be made infinite v=a: now a is a constant at any given temperature for each gas, which can be determined with fair accu- racy from the equation p (v—a) = p’ (v'—a) the pressures p and p’, being a long way apart: and a is therefore a known number: hence the volume taken may be condensed by pressure to a small volume, but never to a volume smaller than a, where a varies very gradually with the tem- perature. Vapour-pressures and Temperatures ;—Regnault. We must now turn to well-known investigations of relations between vapour-pressures and temperatures by Regnault and by others. In a magnificent series of investigations on the vapour-pressures (elastic forces) of water, Regnault' describes various methods, and gives in separate tables the results for separate series treated by these methods for temperatures ranging from 32° to 230°; and discusses the applicability of a number of different formule, by which, after determination of the constants in the formula by reference to a few of the determinations the rest of his results were more or less accurately represented. pressure mm. pressure mm, Lope Leta oe eal re at 200° =. ~=—.—«(11688-96 WelWE Gh daistan yy ER » 230° =... «2092640 The above samples give some idea of the rapid rise of pressure with tem- perature. The empirical formula by which Regnault expressed the results of his observations on other bodies” were of a similar exponential form to those he used for water in t. xxi., the laws. by which Dalton attempted to express the relations being entirely inadequate except over a very short range: these laws of Dalton were— (1) The elasticity of vapour of a liquid increases in geometrical pro- gression when the temperatures follow in arithmetical progression. (2) The vapours of all liquids have equal elastic forces at tempera- tures equidistant from the boiling points at ordinary atmospheric pressure. These laws are replaced by Regnault’s tabulated results, and by the empirical formule he adopted ; for each substance fresh experiments have to be made, and no reliance placed on Dalton’s laws. For water at low temperatures—e.g. from — 32° to 0°—the formula used was F=a + ba®, wherex=t¢ + 382°. 1 Mém. XXT. de Vv Académie, mém. viii. pp. 465-633. 2 Mém. XX VT. de lV Académie, pp. 335-760. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 111 From 0° to 100° the formula log F=a + bat — efit. From 100° to 230° log F = a — ba* — c*; where x =¢t + 20°. The formule used here are of the form proposed by Biot. The mere fact of choosing different formule for different parts of the curve of vapour-pressures, and of choosing these formule from among other exponential formule, shows that these are empirical formule; and from Regnault’s experimental results different systems of formule and interpolation give tables differing slightly from Regnault’s. Compare, e.g., the tables given by Landolt and Bornstein, pp. 40-49, with Regnault’s. Rankine has since suggested the formula log F = a — - - a Magnus! made determinations up to 111° with results agreeing closely with those of Regnault. In ‘Phil. Trans.’ for 1860, p. 220, are given the results of experiments by Fairbairn and Tate, for the pressure and temperature of saturated vapour of water, and for each temperature the ratio of the volume of steam to that of the water for temperatures ranging from about 58° to 144°. The Statical and Dynamical Methods of finding the Relations between Tem- perature and Vapour-pressure. Two distinct methods of finding the relation between pressure and temperature of saturated vapours are used, one by readings of the pres- sures of the vapour over the liquid in a mercury-vacuum at known temperatures, and the other by the readings of a thermometer immersed in the vapour of a liquid boiling at known artificial atmospheric pressures. The first of these methods is called the statical, and the other the dynamical method ;* the former method is only applicable to moderate or low temperatures, at which as at 50° the vapour-pressure of mercury is inconsiderable ; the latter may be applied at high temperatures. Exam- ples of both are given in the case of steam, and the two methods are found, when both are employed, to yield identical results for water. In t. xxvi. p. 642, Regnault says: ‘It is not evident & priori that for a given substance the two methods (static and dynamic) give the same rela- tion between elastic forces and temperatures. The boiling of a liquid is in fact a very complex phenomenon. The vapour which escapes from a boiling liquid has not only to contend against the elastic atmosphere which presses on the liquid, it has to overcome the attraction which the liquid exerts on the molecules which have taken the gaseous state or which tend to take it; it has to overcome the capillary resistance of the liquid walls, which form globules, more or less easily extensible, in which the vapour is imprisoned while it traverses the liquid, &c., &c. These acces- sory resistances can only be overcome by an excess of heat, and there is the fear that the vapour may, on emerging from the liquid, possess at the same time an excess of elastic force (pressure) and an excess of tempera- ture. The two excesses may neutralise each other and disappear, more or ' Poggendorft’s Annalen, xi. p. 225. ? Mémoires, t. xxvi. p. 341. 3 Toid., t. xxi. 112 REPORT—1886. less completely, in the space in which the vapour has to contend now only against the pressure of the atmosphere acting on it.’ Regnault finds that for substances of moderate volatility, for which both methods can be applied, the two methods give identical results, pro- vided the bodies are perfectly pure, but not otherwise; he found that the addition to alcohol, or to carbon bisulphide, of ,,55 of a volatile substance was in each case sufficient to disturb the two curves of either and to destroy their identity. Among the subjects used by Regnault, and which led to this conclusion, were ethyl alcohol, ethyl oxide, carbon bisulphide, chloroform, benzene, carbon tetrachloride, ethyl chloride, ethyl bromide, ethyl iodide, methyl alcohol, acetone, phosphorus terchloride ; these being some of the substances for which Regnault found (‘ Mémoires,’ t. xxvi.) curves of relation of temperature and vapour-pressure by methods and formule similar to those used for water (‘ Mémoires,’ t. xxi.). When a liquid boils with bumping, as in the case of methyl alcohol, liquid SO., liquid NH3;, it may be heated with the vapour over it to temperatures considerably higher than the temperature at which the vapour in each case is, in the static method, in equilibrium with the at- mosphetic pressure (t. xxvi. p. 645). Vapour-pressures from Solid and Inquid—Regnault. Regnault’s experiments on the vapour-pressure on water included pres- sures for low temperatures down to — 32°; t.e. for a long range of tem- perature during which the water is solid—ice. Regnault found that the whole curve was continuous, including this portion of it, and inferred that the solidification of water made no break in the curve of vapour- pressures; in regard to water he says (t. xxi. p. 609) it would be necessary to make corrections of 3 or 4 hundredths of a millimétre, a quantity almost inappreciable to observation, to bring about a complete coincidence between the curve given by the formula log F = a — ba* — ¢/*, in which a=t + 20° and the graphic curve; on p. 599, alluding to a formula which applies very exactly to all observations of his between 0° and 100°, log F=a + bat — ct, he says that the values of the vapour-pressure for temperatures below 0° are constantly very slightly greater than those given by observation, and he therefore does not apply this formula to temperatures under 0°. The fact is that the methods which were em- ployed were not of a nature to show at once that the vapour-pressure from solid water below 0° and liquid water above 0° formed two curves meeting at an angle at 0° or one curve. Regnault himseif attacks this question directly but unsuccessfully, being unable to prove, to his satis- faction, that the state, solid or liquid, of a body exerts an influence on the elastic force of its vapour at a given temperature in the barometric vacuum. On p. 751 he says in reference to water, alluding to the experiments and results obtained for it in t. xxi.: ‘I have proved that the curve con- structed on the experiments [for ice below 0°] presented a perfect con- tinuity with the curve which is given by the elastic forces of the vapours furnished by liquid water at temperatures above 9°.’ Regnault in this part of this mémoire takes other easily frozen bodies to examine ; ethylene dibromide, benzene, glacial acetic acid ; and comes to the conclusion in all these cases that (p. 759) his experiments prove that 1 Mémoires, t. xxvi. pp. 751-760. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 113 ‘the passage of a body from the solid to the liquid state produces no appreciable change in the curve of the elastic forces of its vapour’ (its vapour pressure) ; ‘ this curve keeps a perfect regularity before and after the transformation.’ Ethylene dibromide melts at 9:53° (Regnault, loc. cit.) Af : » » 82° to 84° (J. C.S. xlv. p. 520) Benzene » 9 44° 4, 4°5° (Regnault, loc. cit.) Acetic acid Ge (Regnault, loc. cit.) ws FA ee es ache (Pettersson, J. C.S. 42, 3) It is seen from the convenient position of the melting-points in refer- ence to ordinary temperatures that these bodies are well chosen for this purpose. Asan example we give some results of Regnault for acetic acid :— Liquid acid Solid acid Temp. Vap.-pressure Temp. Vap.-pressure — 0°6$° 4-27 mm. — 0:00° 4°89 mm. — 240° 3°90 mm. — 2°56° 4°26 mm. — 511° 3°35 mm. — 424° 3°93 mm. — 583° 3°56 mm. Thus the curve of vapour-pressures for acetic acid (abscisse temp., and ordinates vap.-pressures) seems to show that there is a difference of vapour-pressure due to state, and that the solid acid has a greater vapour-pressure than the liquid ; but when this acid has been thoroughly dried by distilling over phosphoric anhydride, the results obtained showed the vapour-pressure for the solid acid less than that from the liquid ; but here acetone was recognised as having been developed by the action of ‘the phosphoric anhydride; and although most of this was removed by distillation some, no doubt, remained ; the two specimens of acetic acid were thus impure, one with water, the other with acetone, and they gave contrary results. And no trustworthy results were obtained with the other substances. Thus two interesting questions are raised by Regnault’s investigations on vapour-pressures :— (1) Whether static and dynamic methods give, when carefully per- formed, identical results. (2) Whether when at the same temperature a body can exist either in the solid or in the liquid state the vapour-pressure in both states is the same ; 7.e. whether the pressure is the same from the solid as from the liquid. Regnault decided both these questions in the affirmative; subsequent investigations have confirmed, as I think, Regnault’s answer to the first question, as they have undoubtedly reversed his answer to the second. Application of Theory to the Second Question. It should be mentioned, in reference to the second of these questions, that in 1858 Kirchhoff, from theoretical considerations, showed that if the vapour-pressure of ice and of water were the same at any the same tem- perature, then sud where p is the vapour-pressure, must be different.! This was, from the theoretical point of view, an important step. But in - 1 Poggendorfi’s Annalen, ciii. 1886. I 114 REPORT—1886, reference to both the above questions, if a negative answer is given, it is. important to have a quantitative determination in order that we may know whether the differences in each case are of an order to be detected by experiment, and whether they are definite. Professor James Thomson! published an important paper in which, by the application to Regnanlt’s very extensive and minutely investigated results for water of a thermo- dynamical formula of Sir W. Thomson? he deduced the result that the ratio of the value of for water vapour to the value for ice vapour at the same temperature is 1:13 to 1. The argument of Professor James Thomson is briefly as follows. Take a body which can exist in three states, solid, liquid, and vapour, and which can be examined in respect to each pair, viz., liquid-vapour, vapour-solid, solid-liquid; on a plane surface mark off on an axis of abscissee the temperature, and perpendicular to the abscissee ordinates representing the pressures ; we can then determine by experiment and draw a diagram of the relation between each of the pairs in respect of pressure and temperature ; we shall thus have three lines for this relation, one representing these relations for liquid-vapour, one for solid-vapour, and one for solid-liquid. The two vapour-curves are nearly continuous, but they havea slight angle at the point at which they meet, an angle which would be evident if one of the two were pro- longed ; at the point of junction of these two curves there are then two values of = the third line, for solid-liquid, passes through this same at point, which is therefore called the triple point. The line for liquid-vapour if extended with increasing temperature will abruptly terminate at the critical point. The thermo-dynamic relation supplied by Sir W. Thomson was 2 = CM; in which p is the pressure, and a its rate of increase with temperature, the volume being constant; C is Carnot’s function (=1/T where T is the absolute temperature), and M is the rate of absorption at which heat must be supplied to the substance per wnit augnientation of volume to let it expand without varying in temperature. Apply this formula first to steam with water, and second to steam with ice, at the triple point, which is almost exactly at 0° C. In either case since the vapour-pressure is for any given temperature independent of the volume, dip dt Hence 22. [22° (when p! i » solid with =M/M’ ence ae / i (when p’ is pressure for solid with vapour)=M/M’. is the same in this case whether there is change of volume or not. Now, as determined by Regnault, the heat of evaporation of a gram of water at 0° into steam at 0°=606'5; and the latent heat of fusion of ice is 79; thus M/M’=606/606+79 approximately=1/1:13. Professor J. Thomson took Regnault’s figures for vapour-pressures from ice and water as they stand, together with the various formule which Regnault employed for representing different parts of the curve, and showed, by an exhaustive examination of the whole, that Reenault’s actual determinations were so accurate as in fact to be available for con- 1 Phil. Mag. iv. xlvii. p. 447, 1874. 2 Trans. Roy. Soc. Edinburgh, March 17, 1851. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 115 firming this result of theory that the ice-vapour and water-vapour curves are distinct and meet at an angle. Effect of Pressure on Melting-point. Professor J. Thomson had proved that the melting-point of ice must be lowered by pressure, and had calculated the amount of this lowering of the freezing-point by a given pressure; his result was subsequently experimentally verified by Sir William Thomson. The amount of the lowering is ‘0073n° for n atmospheres of pressure.! Monsson? made experiments with a very powerful hydraulic press with a view to keep ice liquid at a temperature much below zero, or to lower the melting-point of ice many degrees by immense pressure ; these experiments suggested themselves to him in consequence of Sir W. Thomson’s experiment in which by 17 atmospheres’ pressure he lowered the melting-point of ice more than one-tenth of a degree. Mousson ob- tained the following results :—first, he succeeded by great pressure on water in preventing the solidification of it till its temperature was lowered to —5°; second, he lowered the temperature of a piece of ice to —18°, and liquefied it by a pressure which he calculated to have been not less than 13,000 atmospheres, and the diminution of volume he estimated at 13 per cent. Bunsen? obtained results for the raising of melting-points of some substances which eapand during fusion; thus spermaceti at 1 atmo fuses at 47°7°, but at 156 atmos at 50°9°. So paraffin melting at one atmo at 4.6°3° melts at 100 atmos at 49°9°. And Hopkins, with spermaceti, wax, sulphur, and stearine, using pressures up to 800 atmos, obtained a rise of melting-point with increased pressure.‘ Professor Dewar has quite recently ° made a series of experiments by a Cailletet apparatus on the relation between the temperature at which ice melts under different pressures. The temperatures were measured by a thermo-electric arrangement ; a thermo-junction was frozen in a test-tube placed inside the iron bottle of the apparatus, whilst another thermo- junction outside was kept at the constant temperature of ice melting at atmospheric pressure; the two thermo-junctions were connected with a galvanometer, by means of the deflections of the needle of which the differ- ence of temperature of the junctions was deduced. The freezing-point was lowered 0:18° for 25 atmos, and 2-1° for 300 atmos, giving a mean reduction of 0:0072 for 1 atmo. Similar results up to 700 atmos agreed in giving the same reduction per atmosphere. By this method, therefore, it is possible always to graduate the pressure scale of the Cailletet apparatus or to correct the graduations. — Definitions of Boiling-points. The view generally adopted with reference to the boiling-point of a liquid is that it is the temperature at which the vapour given off from its 1 Phil. Mag. (3) xxxvii. p. 123. * Annales de Chimie et de Physique, 1859 (3), lvi. p. 252; Poggendorff’s Annalen, 1858, t. cv. p. 161. * Poggendorft’s Annalen, lxxxi. p. 562. * Report Brit. Assoc. 1854, p. 57. 5 Proc. Roy. Soc. xxx. p. 533. 12 116 REPORT—1886. surface just balances the external actual or artificial atmospheric pressure. This view is, in fact, the basis of all practical attempts to measure boiling-points. Kahlbaum has developed another view, as will be seen. In order to understand it, it is well to bear in mind circumstances, which are not un-. common, which tend to retard or prevent the ebullition and distillation of a liquid, so that a liquid may sometimes be heated far above its ordinary boiling-point without giving out vapour freely. The view commonly taken is that these circumstances are exceptional, in the sense that they may be artificially exaggerated and that the obstacle opposed to boiling is of a variable amount and that therefore no definite boiling- points can be obtained while these circumstances exist; but that if these obstacles can be removed then there is obtained the true boiling- point at the pressure (say 760 mm.), which does not differ sensibly from the temperature at which the vapour given off in vacuo exerts a pressure of 760 mm. Kahlbaum,! in a mémoire published at Leipzig, 1884, develops a theory of ‘specific remission’ (with which we are not concerned here), and in connection with it gives an account of determinations of relations be- tween temperature and vapour-pressure in which he asserts that the static and dynamic conditions of a liquid necessarily give different boiling-points ; and whereas Regnault said that the static method when it can be em- ployed is always to be relied upon as giving trustworthy results, and always to be preferred to the dynamic, Kahlbaum says the dynamic method alone gives the true boiling-point. It is to be borne in mind that Regnault had found that in many cases in which the two curves—one by the statical method and the other by the dynamical method—overlapped, they coincided very nearly when the substances taken were pure. It is quite clear, therefore, that the static and dynamic determinations cannot always disagree as a matter of course, and on account of the necessity of over- coming cohesion, &c. Kahlbaum ? explains at some length his views as to the boiling-points as found by the statical and the dynamical methods, and defines ® boiling- point thus:—‘I call by the name boiling-point that temperature of the vapour of a liquid in agitation at which its molecules can, by their united energy, overcome the collective attractions of neighbouring mole- cules and the external pressure.’ It cannot be doubted that, as in Dufour’s and Gernez’s experi- ments on the retardation of the boiling-point of liquids in the absence of air into which the liquid can evaporate, so in the cases mentioned by Regnault, and in others similar, the temperature of liquid and of vapour may rise in the dynamic method considerably above the temperature at which the vapour-pressure in the static method is in equilibrium with the atmospheric pressure ; that is, both liquid and vapour may be superheated. But these are exceptional cases, and bodies usually boil under circum- stances such that superheating may with care be avoided. Again, it is easy enough by avoiding necessary precautions to heat the vapour above the boiling-point, and so to make the boiling-point of any liquid seem higher than it is. 1 Berichte der Deutschen Chemischen G. 1883, xvi. II. p. 2476; 1884, xvii. I. p. 1245, and p. 1263; 1885, xviii. e 2 Thid. 1884, xvii. I. p. 1263. 8 Loe. cit. p. 1272. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 117 Le Chatelier! gives a list of dissociation-pressures, with the tempera- tures corresponding, as follows :— Temperature Dissociation-pressure 547° : d ; ; 27 mm. BOP or Sunk a) Rae AGiiox 625° : : : : golf, FAQS yeh adel, yr ARE, QS, PARP OM at lave» oleh ere 280+, GUOSeRiitis ., 68 WE DeG78.,,, SIMs Wades vs i> era WHER; SEG ed des. gba Re 4, for several varieties of calciwm carbonate from different sources, all agreeing to give the same dissociation-pressure throughout for each tem- perature as soon as equilibrium had been reached, which was more rapidly done the more finely divided the calcium carbonate. At about 812° the dissociation-pressure was equal to the atmospheric pressure ; on heating rapidly, however, the temperature rose higher, up to 925°, and stood for some time constantly at that point on account of the rapid consumption of heat by the decomposition of the calcium carbo- nate. Analogous results were obtained by Le Chatelier in the decompo- sition of gypsum and of calcium hydrate ; results easily explained by the length of time taken by bodies undergoing dissociation in reaching their state of equilibrium. These higher dissociation temperatures suggest a somewhat similar explanation for cases of overheating such as occur with mercury and other bodies in which there is a difficulty in overcoming cohesion or capillary action.” Proof by Direct Experiment that Curves of Vapour-pressure from Solid and Liquid are different. The difficulty of the problem in the case of water arises from the small- ness of the pressure of vapour of ice even at 0°, viz., 4°6 mm., while for ice at —17-1° the pressure is 1:04 mm. It is easy to see that by any ordinary manometric contrivance it would be difficult to get very satisfactory results for such very low pressures; however, Pettersson in 1881 3 sue- ceeded by this means in getting a few results for temperatures at very small pressures by using a thermometer surrounded with ice, a manometer, and a 4-litre exhausted flask surrounded by a freezing mixture; an arrangement by which the ice round the thermometer distilled without melting, while the manometric pressure corresponding to each temperature of the ice could be observed. Some of the results were in fair accordance with some data given by Regnault for vapour-pressures given by ice at different temperatures below 0°. By this method, as Pettersson points out, the pressure continuously and rapidly changes as the temperature of the ice rapidly rises ; the ther- mometer is therefore not to be expected to indicate the temperature for each pressure accurately, seeing that the ice and the mercury cannot take up the new temperature corresponding to each new pressure instan- taneously. » Compt. Rend. cii. 1243. ? Horstmann in Berichte der Deutschen Chemischen G. xix Ref. p. 429. * Berichte der Deutschen Chemischen G. 14a, p. 1370. 118 REPORT—1886. Analogy of Vaporisation of Solid with Boiling of Liquid. Ramsay and Young! have obtained results for ice by the dynamical method, which are conclusive on this point, that ice has definite tem- peratures of volatilisation without fusing, and for each temperature a definite pressure. In the dynamical method the substance is either boiling or volatilising when its vapour is being formed at a temperature at which the vapour has a pressure just equal to the external pressure. Ramsay and Young used two flasks, each having a thermometer, connected at their necks by a narrow glass tube; the tube was provided with a side tube and a clip, by which it could be either closed against the outer air or attached to a pump; or, what was found more efficacious for excluding every trace of air, well-boiled water was put into the flasks and boiled down in them, so that the steam expelled the air very completely from the apparatus when the clip was closed air-tight after the thermometers had been inserted. On placing one of the two flasks in a freezing mixture, ice at a low temperature was formed, some adhering firmly to the bulb of the ther- mometer. When this flask was put in boiling water and the other in a freezing mixture what happened was this, that after a little time the bulb of the second thermometer was covered with ice, and soon the two thermometers showed the same temperature, which they kept so long as the temperature of the condenser was not altered, and so long as the bulb of the ther- mometer in the other flask was covered with ice. If the temperature of the condenser was changed the two thermometers both soon showed the same lower or higher temperature, but the variation of the temperature of the water-bath had no effect on the temperatures of the thermometers—in other words, on the volatilising point. The fixed point at which the two thermometers agreed in any experi- ment was the temperature at which the pressure of vapour from the ice on the bulb of the thermometer in the flask in the water-bath was just equal to the pressure of the vapour from the ice on the bulb of the ther- mometer in the flask in the condenser. If the air is not completely expelled, or if a very little air is intro- duced, the flask in the water-bath shows a higher temperature than the fiask in the condenser—for this reason, that the ice in the first flask must have a pressure of vapour more than enough to balance the pressure of ice-vapour from the condenser flask by the pressure of the air; the pressure of this small quantity of air will not vary much in any one set of experiments, and therefore by means of the different temperatures of the two thermometers in one experiment and the vapour pressures corre- sponding to the two temperatures we can, by taking the difference between these two pressures, get the pressure of the air in the apparatus, which pressure, being allowed for in the rest of the experiments in the series, there was found always a satisfactorily constant agreement between the volatilising temperature and the condensing temperature ; and not only that, but also that the higher temperature given when air was introduced was the temperature at which the vapour-pressure from ice and the pressure of the air were jointly equal to the pressure found by Regnault as the vapour-pressure of ice at that higher temperature by the statical 1 Phil. Trans. Part I. 1884. ea —( it ie” EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 119 method. Thus the analogy is complete between the volatilisation of ice against external pressure and the boiling of a liquid against external pressure. Similar experiments were made by Ramsay and Young with acetic acid (melting 16:4°), with naphthalene (melting 79:2°), with camphor (melting 175°) ; the results by heating the bulb containing solid camphor adhering to the thermometer were confirmed by the pressures obtained with solid camphor over mercury at different temperatures below 175°, the results agreeing very nearly, as shown ona diagram. The general conclusion to be drawn from this paper is that corresponding to boiling- points of liquids there are similar temperatures for solid bodies volatilising without liquefying—viz., temperatures which are constant while the solid volatilises at a constant pressure, but which are different for different pressures, the volatilising point of a solid rising with rise of pressure, and. being lower with lessened pressure, as is the case with the boiling-point of a liquid ; and moreover that the volatilising point (for any pressure) is the same as the temperature at which the solid over a mercury-vacuum has the same pressure, or sensibly the same; the second method giving the true vapour-pressure, while the former method gives a temperature not absolutely identical with that observed for the same pressure over a mercury-vacuum, though the difference is extremely minute. It was not superfluous to prove by direct experiment the deductions made by Professor James Thomson from Regnault’s numbers as to the discontinuity of the curve for the ice-vapour pressure with the curve for water-vapour pressure, and to show by direct experiment that at tem- peratures common to the two (below the freezing-point), the curves of vapour-pressure are distinct, the one for water-vapour pressure being continuous with the curve for water-vapour pressure above 0°; and it was important to prove that these propositions, mutatis mutandis, apply to other substances. This task, for water, acetic acid, benzene, and camphor, was undertaken and successfully accomplished by Ramsay and Young, and is published in ‘ Phil. Trans.’ Part Il. 1884. Vapour-pressures from Solids and Liquids—Ramsay and Young. In Naumann’s ‘ Thermochemie’ (Brunswick, 1882), at p. 178 is a passage, quoted by Ramsay and Young, showing that Naumann had con- vinced himself that from naphthalene (melting 79'5°), the same vapour- pressure is produced either from liquid or solid at the same temperature ; and he alludes to former experiments (Regnault’s, no doubt), which yielded similar conclusions in the cases of water, benzene, ethene bromide, acetic acid, cyanogen chloride, and carbon tetrachloride. It will be remembered that no satisfactory results were obtained by Regnault with the substances he tried. In the paper referred to' Ramsay and Young first give results for solid camphor, the pressures being found for many temperatures up to the melting-point 175°, and for liquid camphor up to 198°; and it is very evident on the curve of pressures plotted out that the curves for liquid and for solid camphor meet at a re-entering angle near 175°, which is the melting-point for a pressure of one atmosphere. For camphor the operations were conducted by jacket- , ing a barometer-tube, very carefully ensured from the danger of entrance 1 Phil. Trans. 1884, Part II. p. 461. 126 REPORT— 1886. of air or moisture, the tube being heated to the required temperatures by the vapour of aniline (or methyl benzoate) at different pressures. But the method of work and the apparatus devised were varied to suit the requirements of each case. Thus for benzene (melting 3°3°) a modification described in § 17 of the memoir cited on page 19! is used, the bulb of the thermometer being covered with cotton-wool which is soaked with benzene; the benzene persisted in solidifying just below freezing-point 3°3°, As in the previous case of camphor, so in this case of benzene many experiments were made near the melting-point above and below it, and several with the solid at long intervals below and with the liquid at long intervals above. The lines for solid and liquid, which had slight curva- ture, met at a re-entering angle at a point where the temperature was between 3°0° and 3°6°. With acetic acid it was found possible to cool it below the freezing- point 16°4° and keep it liquid, and a large number of good results was obtained; the curves meeting at about 16°3°, the two curves below the melting-point being very obvious, and each being the result of numerous observations. Attempts made with the greatest care by the baro- meter (statical) method gave, as with Regnault, no satisfactory results. The observed difference between the solid-vapour pressure and the liquid-vapour pressure for the same temperature was nowhere much more than l mm. This gives some idea of the accuracy required in this kind of work. The next—and last—case taken in this paper is ice and water. Com- parative results, 7.e. results at identical temperatures for ice-vapour and water-vapour were obtained from 0° to —5°; tables are given of observations of pressure for ice down to —16°; and these results when compared with the results which Professor James Thomson obtained, as mentioned, by recalculation of Regnault’s data, are found to give differences of vapour-pressures of ice and water greater than his. But when the observed pressures for ice, for temperatures below 0°, were compared with the pressures calculated from a theoretical formula of Professor Thomson, the authors found that their observed results agreed more nearly with those so calculated than with those calculated from Regnault’s results. Thus Drs. Ramsay and Young have shown that curves for pressure, from a liquid and a solid state of the same substance, are not continuous in the cases of camphor, benzene, acetic acid, and water. The process in which the thermometer-bulb is covered with cotton- wool (or asbestos fibre), and this soaked with the substance the boil- ing-points of which at different pressures are required, gives results, according to Ramsay and Young, in which the error due to overheating of the vapour is got rid of, for the substance adhering to the cotton- wool has so much free surface that it will, whether solid or liquid, evaporate freely at the temperature corresponding to the pressure to which it is subjected. The cotton-wool can be re-moistened continually by an arrangement described in this paper and in ‘J.C.S.’ January 1885. In the last-mentioned paper they further describe their apparatus, and show how it is used for solids as well as liquids, and apply it in particular to the case of acetic acid. Regnault had obtained discordant results 1 Phil. Trans. Part I. 1884,"p. 47. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 121 with this substance, which sometimes he attributed to the presence of water: and sometimes to the presence of acetone; and the least trace of im- purity, as he has pointed out, affects the results seriously, especially those obtained by the statical method; for over the thermometer vacuum any accidental presence of a trace of air does not get eliminated as in the dynamical method by boiling for a short time. By their method Ramsay and Young got a series of values of pressures for solid acetic acid from —5°68° to 16°41° volatilising point, and for liquid acetic acid from 2°72° to 117°15° boiling-point. The results so obtained agree closely with those given by the usual process when a perfectly pure acetic acid was: used, and disagreed with vapour-pressures previously given by Regnault,' Landolt,? Binean,*? and Wiillner.* Vapour-pressures from Solids and Liquids—W. Fischer. W. Fischer,’ independently of Ramsay and Young, and by a quite- different method, investigated the lines of solid vapour-pressnre and of liquid vapour-pressure for water and benzene for a range of temperature throughout which, in each case, the body could exist either as solid or as liquid ; he arrived at results substantially similar to those of Ramsay and Young. He showed that the curve of pressures for each substance (for temperatures below the melting-point) was lower for solid than for liquid. In the case of ice and water he gives four sets of experiments, in each of which experiments there are given the thermometer reading below 0°, the barometer reading and the reading of an ice-pressure mercury tube and of a water-pressure mercury tube, the three tubes being near together so that they can all be read with the cathetometer, as well as the thermome- ters giving the temperature of the ice and water in each experiment. A fifth set of experiments was made for vapour-pressure of water at tem- peratures above 0°. From these he deduced two equations of the form =a+bt+ct?, which represented very accurately his observations, one for p the vapour-pressure of water, and the other for p the vapour- pressure of ice. These results were got in the winter of 1882-3, and they did not well agree with theory, and especially gave a difference for ice and water at 0°, differing too seriously from that deduced from Clausius’ formula. In the winter 1884-5 he resumed the investigation, and succeeded in improving the method employed so as to make his results more accurate.. In the equation p=a+bt+ct? he obtained the values of a, b, c, his results for the different pairs of values of p and ¢ giving him from the equation between p and ¢ a large number of equations in a, b, and c. This was done for water-vapour and for ice-vapour; the equation for pressure of water-vapour at temperatures between 1°35° and —10°15° was p=4 628 + 0°32535t + 0°008705? and for ice-vapour pressure p=4 641 + 037190 + 00110417? the difference of e for ice and water at 0° is ‘04655; Kirchhoff calcu- 1 Mém. 1862, xxvi. p. 51. 2 Liebig’s Annalen, Suppt. 6, 157. 3 Annales de Chimie et de Physique (3), xviii. 226. 4 Poggendorfi’s Annalen, ciii. p. 529. 5 Wiedemann’s Annalen der Physik und Chemie, 1886, No. 7, p. 400, 122 REPORT—1886. lated it at ‘044. This is, therefore, a tolerably satisfactory agreement. ‘The two curves meet at about 0°3°. For benzene W. Fischer found +5:3° as melting-point ; Regnault had found +4°35°. The equation for the vapour-pressure over solid benzene was found to be p=24°985 + 1°6856¢ + 0:031339? ; that for the vapour-pressure over liquid benzene was p=26-40 +1:4295¢+0:045052. The two curves do not meet at 53°, but they should meet on some point on the line of solid-liquid, and may do so at some point corresponding to a pressure higher than atmospheric. From the diagram it appears that the two curves would not meet for some distance from the melting-point ; this is not certain, but it is so probable as to point to some error, perhaps arising from impurity of the benzene. Vapour-pressures of Mercury. The determination of the relations between temperature and vapour- pressure for mercury was found by Regnault to be very difficult, on account of the occurrence of violent bumping; the results are published in ‘Mémoires,’ t. xxvi. p. 520. The temperatures were measured by an air-thermometer of constant volume, but of small initial pressure, it having been partially exhausted before the beginning of a series of ex- periments. The formula log F=a+ba'+cy' was used, where F is the vapour-pressure, and the constants determined by a sufficient number of data from observations including a wide range; thus the table on pp. 520, 521 was calculated from the formula. Regnault’s observations were too few and too doubtful, and the results given by him for vapour-pres- sures of mercury at low temperatures and at ordinary temperatures have been proved to be quite illusory. A few other physicists have attacked this question; among them Hagen, McLeod, Hertz, and Drs. Ramsay and Young. We will first give Hagen’s results,! comparing some of them with Regnault’s :— Vapour density in mm. Temperature Hagen Regnault 09 0-015 0:020 10° 0:018 0:027 20° 0-021 0-037 30° 0:026 0-053 40° 0-033 0-077 100° 0-210 0-745 Hagen’s differ widely from Regnault’s numbers, but, unfortunately, there is good reason for thinking Hagen’s results entirely untrustworthy in spite of the very great care which he took to avoid sources of error. An experiment of McLeod’s made the early numbers of Hagen (those 2 Wiedemann’s Annalen der Physik und Chemie, 1882, xvi. p. 610. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 123 for ordinary temperatures) very doubtful. It is described in the British Association volume for 1885. A shallow glass tube 14 mm. diameter ‘containing freshly distilled mercury was suspended near the bottom of a closed flask of about 1:9 litre capacity, for nine days; the tube was then removed and boiling nitric acid poured into the flask and allowed to stand some time, the nitric acid neutralised with ammonia, the solution washed out of the flask, acidified with HCl, and treated with HS. By comparison with the result of operating similarly with solutions of mer- eury of known strengths, the mercury was found to be between ‘00006 ems. and -00012 gms. The flask contained, therefore, as vapour about ‘00009 gms. of mercury. A second similar experiment gave ‘00012 gms., therefore at ordinary temperature 1 litre of Hg-vapour contains ‘00006 ems., which would correspond to pressure of mercury="00574 mm. ; and McLeod says this number may be too large, for probably some mercury condensed on the inside of the flask. In Wiedemann’s ‘Ann.’ 1882, xvii. p. 177, is an elaborate investigation of the evaporation of fluids, especially mercury, by Hertz. His vapour- pressures of mercury are very different indeed from Regnault’s from ()° to 100°, as will be seen :— Regnault giving at 0° vapour-pressure 0°02 mm. ° : Hertz af 0 - 0:00019 mm. and Regnault __,, 100° m= 0°7455 mm. Hertz 3 100° as 0285 mm. Ramsay and Young! determine, by a neat and accurate method, in which mercury in a small bulb of glass at one end of a narrow graduated tube is heated to the boiling-point of sulphur, the vapour-pressure of mercury at that temperature; and deduce, from this and a few data for lower temperatures, by means of the formula? R/=R-+c(t’—t)—see further on (p. 125)—the vapour-pressures for temperatures from 360° to 130° from Regnault’s vapour-pressures of water ; and the vapour-pressnres of mercury between 130° and 40° were calculated by ‘ extrapolation’ (loc. cit. p. 48), by means of the known vapour-pressures of mercury at tempera- tures 160°, 220°, and 280°—which pressures and temperatures suffice to find the three constants in the formula log. p=a+ba', which was then applied to find p at lower temperatures. ; Let us compare some of Hertz’ values with those of Ramsay and Young :— ! | Temp. centigrade Hertz Ramsay and Young At 40° ‘0063 mm. ‘008 mm. A MUS OLS eens. O1S, 35 ee 026 =, 029 ,, yr il Ube SO5Ois rs "052, a oO 093 =, 092, US 16D. 5 160 ,, Gos "200 os “Zid a3 » 140° 1:93 5 U7 G3 055 | », 180° 9°23 5 8535, » 200° 18:25 Fy 17-015 ,, 3» 220° 34:90 » 31957 ,, 1 J.C.S., January 1886, p. 37. 2 Phil. Mag. January 1886. 124 REPORT—1886. The remarkable closeness with which these numbers of Hertz and of Ramsay and Young agree is a striking proof of the applicability of the thermal relation R/=R-4 c(t’ —t), explained in ‘ Phil. Mag.’ Jan. 1886, to the determination, with considerable accuracy of data which almost baffle direct experimental treatment. Crookes, in the ‘ Chemical News,’ July 16, 1886, p. 28, writing of the mercury left in his radiant-matter tubes even at great exhaustions, says that, although im the cold it is impossible to get an induction spark through the tube, the interior of it being absolutely non-conducting, yet on heating the tube with a Bunsen flame, keeping the coil going, suddenly the current passes, lighting up the inside of the tube with a greenish blue light, in which the spectroscope shows strong mercury lines. The tube on cooling becomes non-conducting again. This shows, according to Crookes, that in such very highly exhausted vacuum-tubes there is plenty of mercury present, not as vapour, but con- densed on the metallic poles or on the inside of the glass. But a com- plete blockade may be established, as Crookes explains in this paper, whereby during the exhaustion of the vacuum-tube no mercury can enter; the blockade is effected by interposing between the vacuum-tube and the mercury a tube containing freshly heated sulphur and iodide of sulphur packed with freshly heated asbestos, and a glass tube containing copper to retain any sulphur. By this means the vacnum-tube is so freed from mercury that Crookes has been unable to detect mercury vapour in any of the tubes, even on heating them. Tables for Constant Temperatures. The fact that for each pressure there is a corresponding temperature for any volatilisable liquid, constant so long as the pressure is the same ; and for each temperature a pressure of vapour, constant so long as the temperature is the same, can be utilised to secure a constant temperature by boiling a liquid at constant pressure; this is the principle of Hof- mann’s method of determining vapour-densities ; the constant temperature being that of a given liquid boiling at the (constant) pressure of the atmosphere, different liquids must be used boiling at different tempera- tures to give a convenient temperature in each case. The substances which can be used must be few, as they must satisfy the condition of being cheap, stable, and easily obtained pure. Now the number of constant temperatures which can thus be obtained is the number of such bodies the boiling points of which can be used as the constant temperatures ; the temperatures thus attainable will therefore be few and far between. Among the liquids satisfying the conditions mentioned are carbon bisulphide, ethyl alcohol, chlorobenzene, bromobenzene, aniline, methyl salicylate, bromonaphthalene, and mercury. Their approximate boiling- points are 46°, 78°, 182°, 155°, 184°, 222°, 280°, and 358°; thus we have eight temperatures which can be used for purposes for which a constant temperature is required; and they are at fairly uniform intervals from 46° to 358°, applicable therefore to wide ranges of temperature. By the aid of the principle stated above, we can, by keeping constant any pressure below 760 mm. for carbon bisulphide, obtain another con- stant temperature, and in fact a whole series of constant temperatures EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 125 between 0° and 46°, or between 0° and temperatures higher than 46°, e.g. between 0° and 50°, by using constant pressures over 760 mm. This in fact is what! Ramsay and Young have made possible by determining the pressures of the vapour of carbon bisulphide for every degree from 0° to 50° inclusive. Thus instead of only one we have fifty constant temperatures, being boiling-points for sixty known pressures from 127-9 mm. to 857:1 mm.; the temperatures being air-thermometer temperatures; to say that fifty constant temperatures are available is sufficient perhaps; bat in fact other temperatures are obtainable by interpolation between two succes- sive degrees (up to 50°). Similar tables have been prepared by the authors for the other sub- stances for every degree centigrade ; thus for the eight different substances there are eight tables, giving in the case of— Carbon bisulphide vapour pressures from 0° to 50° Ethyl alcohol A, ss pe 40° «7, ; -80° Chlorobenzene a a 35 (Ame WS VAS Bromobenzene Rs “ eel 2) oe ealiG ts » Aniline “3 3 ar Lae jemikene Methy] salicylate = Le A el fa" as 2 ABS Bromonaphthaline 5 PS pi aloe tele Mercury Ss - wi 27 O2eeseSaoOP for each degree centigrade in each table the vapour pressure of the substance. These valuable tables are founded on the definiteness and constancy of the relationship between vapour-pressure and temperature for each pres- sure for each substance; and as most of these results have been obtained by the dynamical method they assume that this method is as trust- worthy as the statical and gives, when properly applied, as definite and constant results. Ramsay and Young’s Formula R’=R-+c (t'—t).—Calculated and observed Tables of the Absolute Temperatures and Vapour-pressures of a Substance compared. In the brief sketch, p. 123, of Ramsay and Young’s method of deter- mining the vapour-pressures of mercury for various temperatures, it was stated that by certain experiments the relation between temperature and vapour-pressure of mercury was determined at about the tempera- ture of boiling sulphur, and that, from this and from three or four data at lower temperatures, a series of pressures for a long range of temperatures was deduced from Regnault’s series for water by the use of an equation of the form R’/=R-+c (#/—?); in this R is the ratio of the absolute tem- perature of two bodies corresponding to any the same vapour-pressure ; R/ the ratio at any other pressure the same for both; #¢/ and tare the tem- peratures of one of the bodies corresponding to the two vapour-pressures ; and ¢ a small constant. What Ramsay and Young have proved ? is that for the substances of widely different kind examined by them, c is very small, that it can be accurately determined, and that it is constant for any pair of substances; that when either water, ethyl alcohol, carbon bisulphide, or sulphur 1 J.C.S. September 1885, p. 640. ? Phil. Mag. January 1886. 126 REPORT—1886. is taken as one of the two substances, as the substance of reference, the observed pressures agree with those calculated by the formula with re- markable accuracy ; and doubtless equal accuracy could be got by using other substances of reference. We will give some results illustrative of the accuracy which this formula shows :— 1. The absolute temperatures of water at various pressures being known, the following are absolute temperatures of CS, calculated from the formula, and absolute temperatures of CS, obtained by observation. Found c=‘0006568. mm. mm. nm. mm. mm. mm. mm. mm. 100 | 200 400 700 1000 | 2000 | 3000 | 5000 | mm. Pressures. . . 50 oes peer! 254-0° | 267°6°| 283-2°| 300:8° | 316-8° | 327-95°| 352-5°| 368-6°| 391-3° Ce aa 254-05°| 267-79] 283-2°| 300:75°| 316°75°| 328-0° | 352-3°| 368-7¢| 391-7° The greatest difference between the observed and the calculated tem- peratures of CS, is here only 0°4° at the pressure 5000 mm. 2. The absolute temperatures of CS, being known for a series of vapour pressures, to find by the formula the absolute temperatures of sulphur at the same pressures. Regnault gives! a list of corresponding temperatures and vapour- pressures for sulphur; taking some of these and the temperatures of CS, for the same pressures, and adding 273 to the temperatures to get the absolute temperatures, the value of c is found= —-0006845. A series of absolute temperatures of sulphur can now be constructed for various pressures by calculation by the formula from the absolute temperatures of CS, at the same pressures; and these can then be com- pared with the data obtained by interpolation from the temperatures and vapour-pressures given by Regnault. The following are among the results for sulphur :— mm. mm. IPECSSULCS Mac wir. ete ices 400 800 1000 2000 3000 mm. mm, mm. | Calculated abs. temp. . 683°5° 724°6° 139°3° 788°15° 820-8° Observed abs. temp. . 683°7° 724:6° | 739°0° | 788°2° 820°8° Besides the substances mentioned, the formula was applied to methyl alcohol, ethyl chloride, ethyl bromide, chlorobenzene, bromobenzene, aniline, methyl salicylate, bromonaphthalene, ethylene, oxygen, acetic acid, nitric peroxide, chloral-alcoholate, chloral-methylalcoholate, ammonium chloride, ammonium carbonate ; and? to carbon tetrachloride, ethyl oxide, chloroform, and mercury (which has been already mentioned). The results in such a variety of cases being extremely accurate for elements such as oxygen and sulphur, and compounds of such different types, there can be no doubt that the relation R/=R-+c (t/—?#) very accurately represents an actual relationship between temperature and vapour-pressure such that the different substances taken are in this way 1 Mém. t. xxvi. p. 527. 2 Phil, Mag. February 1886. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 127 comparable with each other; and the suggestion imposes itself upon one that this may be an expression—very approximately true—of a general law with regard to vapour-pressures and temperatures applicable to any volatilisable liquid—to any at least which can be heated with no chemical change, or none but dissociation; in other words, that bodies of this kind in the liquid state are, in spite of their apparently great divergencies in respect of relations of vapour-pressure to temperature, really very similarly constituted in that respect if compared under physical condi- tions, which this formula of Ramsay and Young in some way represents, at least approximately. Application of the formula to Liquid Oxygen. The case of oxygen is of such interest that it is impossible to leave- this important paper without treating of it. Olszewski’ published a series of determinations by a hydrogen-ther- mometer of temperatures of liquid oxygen, and vapour-pressures corre- sponding, the temperatures varying from the critical temperature of oxygen —118°8° C. to —211°5° C.; and critical pressure being 50-8 atmos = 38,608, mm., and the pressure for the lower temperature being 9 mm. Olszewski was unable to measure any lower temperature, because at this point so much liquid oxygen had evaporated that the bulb of the ther- mometer was not sufficiently covered with it. Taking water to compare with, c was found =—-0003932. By inter- polation from Olszewski’s numbers, temperatures were determined for vapour-pressures 800, 1000, 1500, 2000, and so on up to 20,000 mm.; the critical temperature corresponding to a critical pressure 38,600 mm. of oxygen vapour being about 154° in absolute temperature. The calculated and the interpolated values of absolute temperature of oxygen are as under :— mm. | mm. | mm. | mm. | mm. | mm. | mm. | mm. | mm. Pressure. . . 9 800 | 1000 |} 2000 | 3000 | 5000 | 10000] 15000 | 20000 : coe 635° | 91-6° | 93-7° | 101-12] 106-19} 113-29 124-79] 132-79] 139-1° From observed \ | 61.50] 90 | 93-5° | 100-0°| 105:5°| 113-9°| 125-791 133-091 138-19 abs. temp. | The same comparison of absolute temperatures is made for oxygen and alcohol, the vapour-pressures of alcohol and corresponding tempera- tures being known over a large range” up to 155° C. by air- thermometer, at which temperature the vapour-pressure is 825919 mm. The tempera-’ tures calculated by the formula, from the table for alcohol, give absolute temperatures nearly agreeing with those got from Olszewski’s observed values by interpolation. Again, a third calculation of vapour-pressures and temperatures was made from the data given by Regnault for sulphur? where air-thermo- meter temperatures centigrade are given at intervals of 10° from 390° 1 Compt. Rend. 100, p. 350. J.C.S. 1885, May Abs. p. 476. * Regnault in Mémoires, t. xxvi. p. 375. % Tbid. p. 530. ‘128 RRPORT- 1886) -to 570°. Here c was found as in all the other cases to be constant for several pairs of temperatures compared for the same pressure for sulphur and for oxygen; and the calculated temperatures of oxygen agree with the observed with an error of one degree at the most. Question of Applicability of Hydrogen Thermometer to Low Temperatures. Wroblewski! objects that Olszewski’s results cannot be true at very ‘low temperatures because at, for example, 61°5° (abs. temp.) =—211°5° C. at which the vapour-pressure found by Olszewski for hydrogen is 9 mm., and at temperatures not quite so low as that, we must be getting near the liquefying point of hydrogen, near enough at least to allow of the suspicion that the behaviour of hydrogen may be getting irre- gular, and deviating from the straight course prescribed by Amagat at temperatures above 0° C. 7.e. above 273° of absolute temperature. And Wroblewski’s criticism is probably just; the determination of the lowest temperatures is probably inaccurate; but the points determined by Olszewski, other than the very lowest temperatures, are probably very accurate, as hydrogen evidently has a very low liquefying point, and is far the most regular of the gases, as seen in Amagat’s curves; still though we know from Amagat’s results and from V. Meyer’s that hydrogen at ordinary temperatures and from these up to nearly 1700° C. behaves in the most absolutely regular way in reference to volume, pressure and temperature, where at least the pressure is not excessively great, our knowledge, however highly probable with regard to its behaviour at low ‘temperatures, is conjectural. Wroblewski used two thermo-junctions arranged as a thermo-pile, one junction being kept at constant temperature, such as 0° or 100°, the -other in the liquid the temperature of which is sought, the temperature being inferred from the deflection of the needle of a galvanometer. The elements of the pile were copper and german silver, and results with the pile agreed with results with the hydrogen thermometer down to -—193° C.; but disagreed below that temperature. Other Formule of Ramsay and Young. In the series of papers * the authors discuss two other formule, which ‘might often be useful for getting fair approximations, but which do not give such remarkably accurate results as the formula.of which we have been treating. A recent paper® gives applications of the formula (p. 125) to bromine, ‘iodine, and iodine monochloride. The Use of Formule—Formula of Clausius—Formula of Van der Waals. The application of the principles of thermo-dynamics to many chemical problems may be expected, as in the case we have enlarged upon, to economise experimental work in this way ; a few data will be re- quired, carefully worked out, and a whole set of experiments made with 1 Compt. Rend. 100, p. 979. J.C.S.1885, Abs. Aug. p. 861; cf. Compt. Rend. 101, p. 238; and J.C.S. 1885, Abs. Nov. p. 1101. 2 Phil. Mag. December 1885 and January and February 1886. 3 J.S.C. July 1886. ~~ s EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 129 some one substance. The results of these can then be used to enable us to calculate for a large variety of substances and circumstances, numerical data which could not otherwise be got without the most laborious and tedious investigations. RT k v—a T(w—p)? the relation between the pressure, volume, and absolute temperature of a gas; Sarrau” has determined the constants in this equation for several gases by Amagat’s results, and has deduced the critical temperature, pressure, and molecular volume for oxygen, carbon dioxide, nitrogen, and marsh-gas. In 1873 Van der Waals first published at Leiden his dissertation ‘ On the Continuity of the Gaseous and Liquid States,’ in which he predicts some of the most striking of the results which Amagat five or six years afterwards first published, and long before his most complete and exhaustive treatment of the gases he examined was concluded; and in this disserta- tion, of which a German edition was published at Leipzig in 1881, he proposed a formula (p + ) (v—b) =R(1+at) (p. 62, Leipzig edition) oo One case of this is that of Clausius’ formula,’ p= for asa general relation between volume, pressure, and temperature for a gas; the constants in the equation must of course be determined for each gas.? Baynes calculates from the formula a series of values of pu for ethylene, which agree remarkably with the numbers found by Amagat by experiment. Amagat applies Clausius’ and Van der Waals’ formule to the case of CO,, and finds‘ a portion of the gas well represented by calculations from their formule, but that neither his nor Clausius’ formula represents the whole of his curves. Critical Temperatures and Pressures. Faraday having shown how certain gases might be liquefied, and having himself liquefied a number of those which under ordinary condi- tions are gases, Cagniard de la Tour® showed that when certain liquids were gradually heated in a sealed tube partly filled, suddenly at a certain temperature the line of demarcation between liquid and vapour dis- appeared, and there was nothing to distinguish one part from another part of the tube. Thilorier had noticed that CO, liquid from 0° to 30° expands four times as much as CO, gas between the same temperatures. Andrews’ investigated the effects of pressure on CO, at different temperatures, and arrived at the conclusion that above the temperature 30°9° C. no pressure however great can liquefy the gas, that is, separate it in the tube in which it is confined into two portions, one denser than the other, separated by a line of demarcation. At any temperature below 30:9° he showed that by some pressure under 74 atmos the gas can be liquefied; and at a temperature the » Wied. Ann. 1879, t. ix. p. 127; Annales de Chim. 1883, xxx. p. 358. - * CR. xciv. pp. 639 and 718; J.C.S. Abs. 1882, p. 686. * See Baynes on ‘ Critical Temperature of Ethylene’ in Mature, vol. xxiii. 1880-1, “ Annales de Chimie et de Physique, 1883 (5), xxviii. pp. 500-502. % Ibid. (2), xxi., xxii. *% Thid. 1835 (2), 1x. p. 427. 7 Phil. Trans, B.S. 1869. 1886. K 130 REPORT—1886. least possible below 30°9° the gas just becomes liquefied by a pressure of about 74 atmos. The temperature 30°9° and the pressure 74 atmos were called by Andrews the critical temperature and pressure for CO,. In further re- searches Andrews had found that the critical point was not a point special to CO, and to this body only ; he found a similar behaviour at some point for every liquefied gas or volatile liquid he examined, and in particular for nitrous oxide, hydric chloride, ammonia, ethyl oxide, and bisulphide of carbon. For each of these (and he considered the property to be general) there is a certain temperature below which the body can, by sufficient pressure, be liquefied, and above which no pressure, however great, can liquefy it. The smallest pressure which can liquefy it at immediately below this critical point is the critical pressure. There can be no doubt that in reference to general properties of liquids and gases the critical temperature and pressure are of the greatest im- portance, and that the accurate determination of a number of these will, in conjunction with Andrews’ very complete examination of CO, and with Amagat’s results—carried, as they are, to very high pressures—be among the most valuable data towards a general theory of gases and liquids ; and on the other hand the critical points may be arrived at by a theoretical method, as indicated in a paper by Thorpe and Riicker.' The actual critical temperatures at present known, besides those found by Andrews, have been obtained for the most part by Ramsay in 1880,? by Pawlew- ski,? by Olszewski and Wroblewski, by Sajotschewsky, and by Dewar.‘ In a paper on the liquefaction of oxygen and the critical volumes of liquids,® Dewar ® gives a list of twenty-one critical temperatures and pres- sures in atmospheres, of which we will mention a few :— ne aa Ry P T Srihiea! tam pera- "| Critical pressure P Chlorine . : : ‘ 141°C, 83:9 50 Oxygen . : : = —113° 50 3:2 Nitrogen . : : " ~—146° 35 3°6 Water : * 3 eee er F37OP 195°5 33 Hydric sulphide ; : 100°2° 92 4:0 Ammonia . ‘ : : 130° 115 35 Marsh-gas . : 6 : —99°5° 50 35 Ethyl hydride . ; 5 35° 45°2 68 Cyanogen . % ° : 124° 61:7 6-4 Acetylene . : a 4 37° 68 4:5 where T is the absolute critical temperature=273+t. Of the above Dewar determined ammonia, hydric sulphide, cyanogen, marsh-gas, and ethyl hydride. Ansdell determined acetylene. For Ansdell’s experi- mental determination of physical constants of acetylene and hydrochloric acid, see ‘ Proc. Roy. Soe.’ xxx. 117, and xxxiv. 113. Dewar shows in the above paper how by his modification of Cail- letet’s apparatus the volume and weight, and hence the density, of the 1 J.C0.8. Trans. 1884, p. 135. 2 Proc. Roy. Soc. vol. xxxi. p. 194. 3 Berichte der Deutschen Chemischen G. xv. p. 2460, 1882 ; and ibid. xvi. p. 2633. . 4 Phil. Mag, 1884 (5), vol. xviii. p. 210. 8 Ibid. 6 Tbhid. p. 214. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 131 liquefied portion of a gas may be readily determined, and in particular the density at the critical temperature and pressure. The values of = are proportional to the molecular volumes of the gases at the critical point. We have thus the means of determining the critical temperature, pressure, and volume of a gas or liquid. These are the most important data for each substance, and the most important points of reference when we compare different substances, which are gasifiable, with one another. It has already been mentioned, p. 129, that Sarrau deduced the critical temperatures and pressures of oxygen and nitrogen by applying Clausius’ formula to Amagat’s results. Sarranu found for owygen t,= —105°4°; p,=48°7 atmos ; and for nitrogen t,= —123°8°; p,=42'1 atmos. The values found by Wroblewski and Oblewski for oxygen are respectively :—! Oxygen, Wroblewski, ¢,=—113°; p,=50 atmos. » Oblewski, ¢—=—118°8°; p,.=50'8 atmos. \ The pressure found by both observers does not differ much from that cal- culated by Sarrau; but the temperature calculated is considerably higher than that observed by either. __ Hydrogen has, so far as I know, not been examined as yet in the liquid state ; but if not, there can be little doubt that it soon will be. Wroblew- ski, by means of nitrogen boiling in a vacuum, cooled hydrogen to a tem- perature 208°—211°, at a pressure 180—190 atmos, and found on suddenly releasing the pressure a grey mist form, which is due no doubt to the formation of liquid hydrogen in a very fine state of division. Sarrau deduced from Clausius’ formula for hydrogen the critical tem- perature —174°, and critical pressure 98°9 atmospheres. The ratio of absolute critical temperature to critical pressure is therefore about 1:0. Again Olszewski? has obtained his lowest temperatures by the eva- poration of solid nitrogen under a pressure of 4 mm., a temperature — 225° having been thus registered by his hydrogen thermometer, which perhaps cannot give accurate temperatures in these extreme circumstances. However, hydrogen does not seem to liquefy at this temperature ; at least no meniscus was seen at —220° at pressures up to 180 atmos; still the hydrogen-thermometer might, and probably would, register too low. The solid nitrogen which Olszewski used was obtained by evaporation of the liquid nitrogen at 4 mm. in a glass tube surrounded by liquid oxygen. The temperature at which nitrogen solidifies is, according to Wroblewski,? —203°. Dewar has recently obtained solid oxygen, but details have not yet been published. Pawlewski had stated, as an empirical law, that the difference between the critical temperature and the boiling-point is constant. This has been found to be by no means true. Vincent and Chappuis‘ find the critical temperature, boiling-point, critical pressure, and the ratio T/P, where T is the absolute critical temperature, for hydric chloride, methyl chloride, ethyl chloride, ammonia, and methyl-, dimethyl-, and trimethyl-amines ; the differences between the centigrade critical temperatures and boiling- points for these in order are 86°5°, 165°2°, 195°, 169°5°, 157°, 155°, and 1 CR. xevii. 309; c. 350. 3 Tbid. cii. 2 Thid. ci. p. 238, § Thid. ci. 427. K2 132 REPORT—1886. 151:2°. In this paper the authors confirm the results of Dewar with regard to the values of T/P, which is 3°5 approximately for hydric chlo- ride water, ammonia, and marsh-gas, and is greater than this for the more complex molecules derived from these as types. In the order in which the bodies have been named these numbers are given as 3°4, 5:7, 8:4, 3°6, 5°9, 7°9, 10°5. In another paper! the same authors add critical temperatures and pres- sures and values of T/P for other substances; thus for propyl chloride T/P is 10, for ethylamine 6:8, for diethylamine 12:2, for triethylamine 17:4, for propylamine 9°8, and for dipropylamine 17:7. Dilatations: and Vapour-densities of Bodies im the State of Gas at High Temperatures—Experiments by V. Meyer, Crafts and Meier, and others. The greater part of the determinations of vapour-densities of bodies whose vapour-densities had not been known or were doubtful up to the last ten years has been effected by Victor Meyer alone, or in conjunction with others ; some by Crafts and Meier.” , After describing his apparatus as ordinarily used, V. Meyer gives results with CHOCl;,, CS, H,O, C,;H,(CH3)., C;H;Br, C,;H;NH,, cymene, C,H;OH, those having the highest boiling-point being heated in the vapour of boiling ethyl benzoate, the vapour-densities in all the cases taken agreeing fairly with the theoretical results calculated from Gay- Lussac’s or Avogadro’s law—quite nearly enough for practical purposes— thus: For CS, For H,O Observed Calculated Observed Calculated 2°87 2:91 2-292 2°63 69) <“66.< "62 62 V. Meyer points out that in calculating the observed densities from the direct datum of each experiment the temperature of the bath does not require to be known, but must be quite constant during each determination. By improving his process he shows how to get much more accurate results, thus : For Water For CS, For Iodine Found Calculated Found Calculated Found Calculated Density 64 62 2°68 2°62 8°83 8:78 and so for, besides those already mentioned, naphthalene, benzoic acid; some in a lead-bath, e.g., diphenylamine, mercury, anthracene, anthra- quinone, chrysene, sulphur; and, in a bath of Wood’s metal, perchlor- diphenyl. For indium chloride the formula InCl, corresponded to the found vapour-density, whereas the vapour-densities found by Deville and 1 Thid. ciii. 6. 2 References; Berichte der Deutschen Chemischen G. 1878, 11. 2, pp. 1868, 2258 ; 1879, 12. 1, pp. 618, 1113, 1195, 1282; 12. 2. p. 1428 (V. and C. Meyer); 1880, 13. 1, pp. 423, 776, 851, 1018, 1033 (Crafts and Meier); pp. 391, 394, 401, 407; pp. 399, 404, 811 (V. Meyer and Ziiblin) ; pp. 1010, 1013, 1721, 2019 ; 1881, ¢bid. 14b, p. 14538; 1882, ibid. 15b, p. 2769; 1883, ibid. 16a, p. 457 (Crafts); 1884, ibid. 17a, 1334; 1885, ibid. 18 Ref. p. 1383 (C. Langer and V. Meyer); a, p. 1501. And Pyrochemische Untersuchungen, von Carl Langer und Victor Meyer. Bruns- wick, 1885. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 133 Troost ' gave Fe,Cl,, Al.Cl,, AloBrg, AlyIg, from about 400° to 1040° (the boiling-point (?) of zinc). These formule had led V. Meyer to expect In,Cl,, which was not given by any vaponr-density determination of indium chloride. So V. and C. Meyer find formule Sn,Cly, ZnCl, for temperatures between 620° and 700° as determined by a block of pla- tinum and a calorimeter. Mitscherlich had found at 571° As,O,, and V. and C. Meyer find for a much higher temperature—about 1000°—the same formula As,O,, and for even higher temperatures Sb,O,, Cu,Cl,, and at over 900° CdBr,; S, at about 1500° (?), while at temperatures below a bright red heat the vapour-density gave S,;. They tried potassium, sodium, and then chlorine, but found that these attacked porcelain. The temperatures in these experiments with the calorimeter and the heated block of platinum were not very accurate when very high tempe- ratures were to be measured. The highest estimated temperature 1567° gave O, (from Ag,O), No, S, as the molecular formule of oxygen, nitrogen, and sulphur. For chlorine at the highest temperature of their furnace they obtained a molecular formula 2Cl,, that is, from Pt,Cl, the chlorine given off, which at as high a temperature as about 620° had given density corresponding to formula Cl,, had given smaller and smaller values for the densities at higher temperatures, till at the highest tem- perature it had a density 1:60, 1-62, a little less than 1-63 calculated for 3Cl,; admitting that chlorine was undergoing dissociation it was not clear that it would not at higher temperatures give still lower densities (always compared with air). The results thus given for chlorine naturally led to speculation as to the behaviour of bromine and iodine in the same circumstances; and as Deville and Troost had (Joc. cit.) found for iodine a normal vapour- density corresponding to I, at the bright-red heat required for reaching the boiling-point of zine (1040°, as found by Deville and Troost) the result with chlorine was considered doubtful; this taken in conjunction with the fact of the porcelain being attacked by alkali metals and chlorides led to a revision of the arrangement of the apparatus. In succeeding investigations V. Meyer, in conjunction with Ziiblin, used a porcelain tube glazed inside and out, and placed in the furnace so as to be heated by it when necessary to the highest temperatures. The gases of the furnace were thus entirely unable to diffuse into the interior of the porcelain tube, and thus the platinum tube which was inside the porcelain tube was absolutely guarded against the action of these gases, and operations which would be vitiated by the action, either of the gases of the furnace on porcelain, or of the substance which was the subject of the experiment, could be heated with safety to the highest attainable farnace temperatures in the platinum tube. The experimental tube was filled with nitrogen, and the vapour-density determined in an atmosphere of this gas. The temperature was now accurately determined (it having been previously found that up to very high temperatures nitrogen, oxygen, mercury, and, as afterwards shown, hydrogen, when compared at the same temperature, gave always vapour-densities corresponding to the same formula; in fact, that in all these cases the absolute densities diminished as temperature rose always in the same ratio) by measuring the nitrogen which filled the tube before the experiment, and the nitrogen which filled it after the experiment. ' Annales de Chimie et de Physique, 1860 (3), viii, p. 257. 134 REPORT—1886. Thenitrogen with which the tube had been filled before the experiment was expelled by CO, till the CO, was entirely absorbed by potash ; this gives the amount of nitrogen left at the highest temperature of the experi- ment. Afterthe furnace had quite cooled the tube was again filled with nitrogen at the temperature of the room, and the amount of nitrogen at this temperature determined in the same way. The expansion of the nitrogen is thus known between the two temperatures; the highest temperature is thus easily calculated on the faith of the accuracy of Gay- Lussac’s law for nitrogen through this range of temperature. As an example of this method they apply it to the case of mercury vapour, and find in two experiments 6°89, 6°76, as against the calculated number 6°91. The method described above for determining the temperature may be called the nitrogen-thermometer method ; its applicability has been amply justified by further comparisons of its densities with those of other gases at still higher temperatures, with, among these, the gases hydrogen, oxygen, mercury. The Behaviour of Iodine at High Temperature. In the meantime (year 1879) Crafts, using a modification of V. Meyer’s apparatus, found for chlorine no alteration of density, or at the most only a few hundredths at the highest temperature of the furnace; but for bro- mine, which for Br, should have density 5:7, was found 4°39 at the highest temperature ; while the density of iodine, which for I, should be 8:795, was found reduced to 5°93.!_ Thus Crafts found vapour-density of iodine reduced in ratio 1°5 to 1; of bromine in ratio 1:2 to 1; and of chlorine very slightly reduced, if reduced at all. V. Meyer also found the vapour-density of iodine reduced in ratio 15 to 1, being abnormal above 590°. ‘ Crafts and Meier,” by a quite different experimental method from that used by V. Meyer, arrived at results which showed that the temperatures were inaccurate in Meyer’s experiments with iodine, and that whereas according to V. Meyer’s figures the vapour-density of iodine remains constant between 1000° and 1570°, Crafts and Meier * show that it con- tinually diminishes as the temperature rises up to 1400°, when it has a density less than two-thirds the density required by the formula I,. Since then Crafts and Meier‘ extended their experiments to higher tempera- tures, operating under reduced pressure. They find that they get a vapour-pressure of iodine above 1300° (at ‘1 atmo pressure), which is near to half that for I,—namely, about 4°6—and which remains nearly constant, slightly diminishing for all temperatures up to 1400°, the curves showing the vapour-densities as ordinates and the temperatures as abscisse. Deville and Troost,’ on referring back to an experiment made many years ago (in 1860) on the density of vapour of selenium by comparison with that of iodine at some very high temperature, find a note appended, to the effect that there must have been some mistake made in the weight of iodine remaining in the flask, for with the number given, 0-011 gram, a temperature of nearly 2000° wonld be attained; they in this communica- tion recognise that the experiment was accurate and that the smallness of the weight of iodine was due to the abnormal diminution in the vapour- 1 C.R. xe. p. 183. 2 Ibid. p. 690. 3 Ibid. 4 Ibid. xcii. 39. 5 Ibid. xci. pp. 54, 83. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 1395 density of iodine at the very high temperature—yet much below 2000°— in this experiment. Troost had also recognised the influence of reduction of pressure on the vapour-density of iodine, and had in fact obtained for a constant temperature, 440°, a series of vapour-densities of iodine (relative to air at same temperature and pressures), as under :— Pressures. 768mm. 67°2 mm. 48°6mm. 48°57 mm. 34°52 mm. Dateien S70 ggg 8 | RB p68 the yige The conclusion which was drawn by Crafts and Meier from their ex- periments was that the molecule I, had been gradually decomposed into molecules I. Troost considered that such a dissociation could not be effected by a simple diminution of pressure; but there are cases of chemi- cal compounds, which can be formed at a low temperature and by suffi- cient pressure, which can be decomposed, partially or wholly, either by raising the temperature or by diminishing the pressure, or by both con- bined, and which can be re-formed by lowering the temperature or in- creasing the pressure. A remarkable instance of this is phosphonium chloride, formed by Ogier ! by combining PH; with HCl. These two gases do not combine at ordinary temperatures, but were by Ogier brought into combination by a pressure of about 20 atmos at 14°, also by lowering the temperature of the mixed gases to —30°. In the former method he fills over mercury the ordinary tube of ‘Cailletet’s elegant apparatus’ with a mixture of equal volumes of PH; and HCl, and when a sufficient pressure has been applied brilliant crystals of PH,Cl appear ; on warming the upper part of the tube, at about 20°, a liquid layer forms which is either liquid phospho- nium chloride or a mixture of the liquefied gases. Ogier says that on gradually cooling the mixed gases the deposit of crystals takes place almost suddenly at —30°; but he thinks it possible that the gases may be in combination at a somewhat higher temperature. That is a matter which experiment has not decided. Now Van’t Hoff,? by compressing a mixture of equal volumes of the mixture of PH; and HCl, got the laboratory-tube of a Cailletet’s apparatus half-full of the white phosphonium-chloride crystals, These he heated with a water-bath ; the crystals melted at 25°; and on heating further at pressure of between 80 and 90 atmos till the temperature was between 50° and 51°, the boundary between liquid and vapour disappeared ; on again lowering the temperature there was noticed the hazy appearance which is characteristic of the critical point. The liquid state (?) of the phosphonium chloride obtained by warming the crystals, or the crystals themselves obtained by pressure at 14°, on gradually diminishing the pressure, gradually disappear, being converted without changing the temperature of 14° into PH; and HCl; here is an exact analogy with the case of iodine in Troost’s experiments with dimi- nishing pressure, for we may suppose the molecules I, to gradually de- compose, on the pressure being relieved, into molecules I. The theory of Crafts and Meier, accepted by V. Meyer, that molecule I, is split into two molecules I, though not overthrown by the experi- ments of Troost, is barely proved by Crafts’ and Meier’s experiments ; for ”? 1 Annales de Chimie et de Physique, 1880 (5), xx. p. 63. 2 Berichte der Deutschen Chemischen G. xviii. 2088. 136 REPORT—1886. these find only a small portion of curve representing a nearly constant vapour-density nearly equal to that required by the molecule I—just enough to convince all who wish to be convinced—and until by higher temperatures there can be shown a longer range during which the density of iodine vapour is always (compared with air) half what it is at ordinary temperatures, that is to say shows no tendency to diminish further, the evidence from the experiments mentioned will be accepted as conclusive only by chemists and physicists who have a predisposition to accept the conclusion. But confirmatory evidence of some fundamental change in iodine at high temperatures is given by the fact that it gives a band spec- trum when subjected to electrical discharges of comparatively low tension, and a line spectrum under higher tension.! The results obtained for chlorine and bromine were a diminution of density continuing up to the highest furnace temperatures under which the experiments could be performed ; it is impossible to use a much higher temperature than 1700° with platinum vessels, for platinum melts a little above this—at 1775° according to Violle?—and is very appreciably attacked by chlorine at a white heat. At about 970° stannous chloride was found to have vapour density corresponding to SnCl,, the density found about 200° lower corresponding to Sn,Cl,; and Fe,Cl, had density at white heat much diminished; while the formulz Al,Cl,, &c., were in concordance with vapour-densities found at the highest temperature; HgCl, was found again to be the molecular weight corresponding to the vapour-density of mercuric chloride at the highest temperatures, the compound thus showing evidence of not having been dissociated at these high temperatures ; and SO, had vapour-density for this formula at a white heat. CO was® partially decomposed at 1690° thus, 2CO=C+CO,; on this account the volume is less than it should be, and also on account of a slight diffusion of the CO through the plati- num at the high temperature ; hence there is found, in place of an ab- normal expansion of CO, a slightly increased density (as compared with air at the same temperature); there is almost normal expansion of CO up to 1200°, but at much higher temperatures decomposition begins to set in. N,0 is almost entirely split up at 900° into nitrogen and oxygen ; and at 1690° it is split up to just about the same extent. NO is entirely decomposed into nitrogen and oxygen at 1690°, but is unaltered at 1200°. HCl was considerably decomposed at 1300° and higher temperatures, the hydrogen diffusing through the platinum, and the chlorine being shown by the amount of iodine liberated from potassium iodide solution. CO,, heated in polished platinum, was only very slightly decomposed at the highest temperature, about 1690°; in presence of fragments of porcelain Deville had found much dissociation at 1300°. The Cumulative Evidence for Avogadro's Law—Application of the Law to the Behaviour of the Halogens at High Temperature. In a paper on some points of the atomic theory, published in 1826, Dumas‘ gave determinations of the vapour densities of iodine and mercury, 1 CR. 1xxv. p. 76. 2 C.R. Ixxxix. 702. * Langer and Meyer’s Pyrochemische Untersuchungen. * Annales de Chimie et de Physique (2), xxxiii. p. 337, 1826. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. Lae: and of some volatile compounds of these and of other less volatile elements... His object was to deduce from his results, by applying to them the atomic _ theory as expounded by Dalton and the law of Ampére and Avogadro. as to the distribution of the molecules of a gas or gasified body, the mole- cular weights of both the compounds and the elements. In this Dumas was only partially successful, because with Dalton he made the tacit assumption that in the case of elementary substances there was no distinction between anatomand a molecule. Chemists before Dumas’ time had taken no account of the law of Avogadro and Ampére in their endeavours to determine the true formule of compounds and the atomic or molecular weights to be assigned to elements, with the exception of Gay-Lussac, who was guided by some adumbration of this law in his investigations into the volume: relations of bodies composed of gaseous components. In the investigation which Dumas records in this paper he not only recognises this law, but takes it as the foundation of the reasoning he: apples to his experimental results; thus inaugurating a method of chemical research which was afterwards renewed by Gerhardt in 1843 and carried by him to a more successful conclusion, for Gerhardt was not only able to show how formule for compounds and especially for very numerous carbon-compounds were consistent with Avogadro’s law, but to include the molecules of volatile elements also under the self-same law. These chemical consequences derived from this law are not anticipated by Dalton’s atomic theory, and without some such physical conception of the constitution of matter in the gaseous state we could not have had any reason to suppose that the weights of substances in this state in equal volumes were in any relation to the chemical formule. But the facts, numerous as they were, which Gerhardt found to show this relation have since the publication of his memoir up to the present time been increased to a vast extent; so that it is beyond question that Avogadro and Ampére’ expressed, with reference to the number of molecules in a given volume, in the case of bodies in the state of perfect gas, a law which is approxi- mately true of vapours of bodies at temperatures far removed from the point of liquefaction, and which not only physicists can use with safety in explaining physical properties but chemists to find true chemical’ formule. There are, it is true, cases of apparent exception, but on examination itis found that in these cases the body, of which we are trying to find the- formula by this law, has wholly or partly ceased to exist in the circum- stances of the experiment, being replaced by two or more other bodies: resulting from decomposition of the original. The applicability of Avogadro’s law which is thus shown, depends of course on the approximate truth of Boyle’s and Gay-Lussac’s laws, which as approximations are thus indirectly confirmed ; and V. Meyer and others have confirmed these laws by their results for very high temperatures, not only in the cases of’ hydrogen, oxygen, and nitrogen, but in the cases of mercury, mercuric chloride, arsenicum, phosphorus, arsenious oxide; aluminium chloride, bromide, and iodide, indium chloride, antimonious oxide, cupric chloride, and cadmium. Moreover, in many other cases where the results do not seem in accordance with these laws at high temperatures we have signs. of a decomposition, while in other such cases the result has been shown to be capable, without any straining of the facts, of simple explanation by supposing a molecule to be split into molecules of half the mass and represented by halving the formule, e.g., in the case of Sn,Cl, which ap- 138 REPORT—1886. pears to obey the above laws up to a certain temperature, to deviate from them for a range of higher temperatures, and tu obey them for a still higher range, all of which facts receive an obvious and natural ex- planation on the supposition that Sn,Cl, splits up gradually into two molecules SnCl, as the temperature rises. In face of all the above facts, which are of somewhat recent develop- ment, and which result from the long-continued labours of V. Meyer, Crafts and Meier, and others, it is difficult to hold the view expressed by Berthelot,! that Boyle’s (or Mariotte’s) law, and Gay-Lussac’s law have only been proved for hydrogen, oxygen, and nitrogen, with the implied in- ference that iodine is probably merely one of very numerous exceptions, and that therefore Avogadro’s law does not hold good for the halogens, and in the other cases which are apparent exceptions to the other two laws. Deville and Troost—Vapour-densities determined by them in 1860—Bearing of their Results on the Behaviour of Iodine. Dumas, in his paper already mentioned, recognised the importance of determinations of vapour densities as aiding the solution of chemical pro- blems, and particularly in helping to give the correct formula to a com- pound. Deville and Troost? used substantially the same method as Dumas, except that by using porcelain globes instead of glass globes they were able to determine vapour-densities of bodies which have very high boiling-points. The matter of chief importance is to have a fiwed temperature above the boiling-point of the substance in the flask at which the flask and its contents can be kept before closing it when it is full of the vapour at the constant temperature. They used for constant temperatures the boiling-points of mercury, sulphur, cadmium, and zinc ; taken as 350°, 440°, 860°, and 1040° respectively. In this way Deville and Troost determine the vapour-densities of water and aluminium chlo- ride at the temperature of boiling mercury ; again, at the temperature of boiling sulphur, the densities of air, iodine, mercurous chloride (4 vols.), aluminium chloride, aluminium bromide, aluminium iodide, zirconium chloride, ferric chloride; in the vapour of boiling cadmium, 860°, the densities of the following: iodine, air, sulphur, selenium; in the vapour of boiling zinc, the densities of iodine, air, ammonium chloride (4 vols.), phosphorus, cadmium, selenium, and sulphur. The boiling-points of the substances above mentioned, whose vapour- -densities have been determined by Deville and Troost, were taken as: water 100°; aluminium chloride 180°; aluminium bromide 260°; zirco- nium chloride (?); ferric chloride 306°; iodine 250°; sulphur 440°; selenium 665°; phosphorus 287°; cadmium 860°. It will be seen that even if these boiling-points are not so accurate as could be wished, in each case the temperature at which the vapour-density was determined was far above the boiling-point of the substance. The substances chosen for giving invariable temperatures of boiling- point were all elements: these were probably selected, among other reasons, because elements were not likely to show any alteration at high temperatures, and, therefore, any serious deviation from Gay-Lussac’s. law. The vapour-density of iodine was used three times, viz., at tempera- 1 Annales de Chimie et de Physique, 1881 (5), xxii. p. 456. 2 Tbid, (3), lviii. p. 257, 1860. EXPERIMENTAL KNOWLEDGE OF THE PROPERTIES OF MATTER. 139 ture of boiling sulphur 440°, boiling cadmium! [860°], and boiling zinc [1040°]. In the first and last cases it was used as the thermometric substance, i.e. the expansion of the iodine (assumed as obeying Gay- Lussac’s law) was known by the amount left in the flask after the experiment was over ; and as the vapour of iodine is heavy, iodine should be an accurate thermometric substance, used in this way by weighing the iodine left in the flask. Unfortunately it has since been found that iodine does not obey Gay-Lussac’s law above 590°, above this temperature its rate of expansion increasing. But in Deville and Troost’s experiments the (relative) vapour-density of iodine is almost the same at [860°] as at 440°, viz., 8:7.2_ This seems inconsistent with what was said just now ; there may be some error here, or it may be, as is likely from analogy, that the dissociation of iodine molecules imagined by V. Meyer, and by Crafts and Meier, may be a slow process requiring more time than was given in this experiment. However that may be, the use of iodine as a thermometric substance for giving the boiling-point of zinc was not legitimate, and Deville and Troost themselves have since found that? the boiling-point of zinc was over-estimated by 100°, the true boiling-point of zine being in fact 940° ; the more than normal expansion of iodine at 940° had given a result due to a normal expansion at 1040°. The cubic expansion of the porcelain of which the flasks were made was determined by Deville and Troost and found to amount to ‘009288 between 0° and the boiling-point of cadmium, which was supposed to be 860° but is now known to be about 772°, as found by Carnelley and Carleton Williams (‘J.C.S.’ 1878, xxxili. 284.) Third Report of the Committee, consisting of Professor BALFour Stewart (Secretary), Mr. J. Knox Laueuton, Mr. G. J. Symons, Mr. R. H. Scorr, and Mr. Jounstonz Stoney, appointed for the purpose of co-operating with Mr. E. J. Lown in his project of establishing w Meteorological Observatory near Chepstow on a permanent and scientific basis. In their last report this Committee, after expressing their opinion that the establishment of a permanently endowed meteorological observa- tory on a good site, such as that of Shire Newton, is a matter of un- deniable scientific importance, instructed their Secretary to write as follows to Mr. Lowe :— ‘The Committee request me to point out to you that the main feature of your proposal, which interests the British Association and the scientific public generally, is the prospect which it holds out of the establishment of a permanent institution by means of which meteorological constants could be determined, and any secular change which may take place therein in the course of a long period of years be ascertained. It will be for you and the local authorities to decide what amount of work of local interest should be contemplated, and on this will the scale of the observa- 1 C.R. xlix. p. 240. 2 Ann. Chim. et Phys. 1860, lviii. p. 285. 3 CR. xc. p. 793. 140 REPORT—1886. tory mainly depend. The Committee are therefore unable to say what amount of capital would be required. They would point out four con- ditions which they hold to be indispensable :— ‘1. The area of ground appropriated should be sufficient to ensure freedom from the effect of subsequent building in the neighbourhood. ‘2. A sufficient endowment fund of at least 150/. annually should be created. ‘3. The control should be in the hands of a body which is in itself permanent as far as can be foreseen. ‘4, The land for the site shall be handed over absolutely to the above- mentioned governing body.’ This communication from the Committee has been submitted to the consideration of Mr. Lowe and his friends, and a letter from Mr. Lowe has been recently received by Dr. Stewart, of which the following are extracts. Mr. Lowe—who offers to give an acre of land, his instruments, and meteorological books, and to work gratuitously at the observatory— writes as follows (July 21, 1886) :— ‘Yesterday sixteen scientific men from Bristol came over to look at the proposed site of the observatory, and said that it seemed a pity that nothing. was being done. ... If any alteration in the scheme would be desirable this could be done, as all that is required is an observatory that would be useful to science. You have yourself seen the site, and if you can suggest what would improve the proposal I have uo doubt it would be acted upon. ... Newport would have had a meeting in November, but the election came on and it was thought desirable to post- pone it. Then the High Sheriff died—the second that had consented to call a meeting—and you will recollect that I told you that Mr. Cart- wright, another High Sheriff, had died. ‘The Committee think that they see their way to getting two or three thousand pounds if the scheme were started. Since you were with me I have purchased nearly 150 acres of land in front of the observatory, and nothing could come between it and the channel as near as 14 to 2 miles. A new road is to be made to the Severn Tunnel station, and I hear that the telegraph or telephone is likely to be carried up this road. ‘If your Committee think well to recommend the observatory scheme, action would be at once taken, and we have reason to believe that the Bristol Docks would help us with 100/. a year. I should much like to see such an observatory in working order whilst I live, but my time is getting short. ‘There is a growing interest round here about the observatory, and constant inquiries are made as to the probabilities of success,’ The Committee express their sympathy with Mr. Lowe and his friends under the unfortunate circumstances that have tended to retard local action. The Committee see such evidence of local interest in the undertaking that they desire to have an early opportunity of co-operat- ing with the local committee. They therefore ask for their reappoint- ment, and request that the unexpended sum of 25/. and an additional sum of the same amount—in all 50/.—be placed at their disposal for the purpose. DIFFERENTIAL GRAVITY METER COMMITTEE. 141 Report of the Committee, consisting of General J.T. Watkzr, Sir W. Tuomson, Sir J. H. Lerroy, General R. Stracuny, Professor A. S. Herscurt, Professor G. Curystat, Professor C. Niven, Professor A. Scuustsr, and Professor J. H. Poyntine (Secretary), appointed for the purpose of inviting designs for a good Differential Gravity Meter in supersession of the pendulum, whereby satisfactory results may be obtained at each station of observation in a few hours, instead of the many days over which it is necessary to extend the pendulum observations. THe Committee have issued the following circular. They subsequently learnt of the work of M. Mascart in this direction. An account of his investigation is appended. Copy of the Circular. The Committee hereby invite designs for an instrument to fulfil the above condition. It should aim to give some ‘statical’ measure of variation in the weight of a fixed mass in place of the present laborious ‘dynamical’ method by means of the pendulum. The principle of a statical differential gravity meter was very clearly stated by Sir J. Herschel in his ‘Outlines of Astronomy’ (§ 189 in editions 1-4, § 234 in later editions). He suggested, in illustration of the principle, a weight suspended by a spiral spring, the spring being always stretched to the same length, whatever the variations of gravity, by the addition or removal of small weights. There appear to have been only three attempts to construct such an instrument, resulting in the torsion Gravimeter of the late J. Allan Broun and the two bathometers of the late Sir C. W. Siemens. A full account of Mr. Broun’s instru- ment, by Colonel Herschel, will be found in the ‘ Proceedings of the Royal Society ’ (vol. xxxii. p.507). An account is also given there of a proposal for a similar instrument by M. Babinet, though the proposal does not seem to have been carried out. In Mr. Broun’s Torsion Gravimeter a mass is supported by a bifilar suspension; a third single wire along the axis of suspension is also attached to the mass, and this third wire is twisted till the mass is turned through 90°. If the weight increases the amount of torsion of the single wire required to keep the weight at 90° from its original position is increased. For details, see Colonel Hersvhel’s paper, which contains a careful criticism of the instrument. Sir C. W. Siemens’ Bathometers are shortly described by Colonel Herschel (loc, cit. p. 515), but a fall account of them will be found in the ‘ Phil. Trans.’ 1876. The first instrument was virtually a barometer with the cistern at the bottom containing a considerable quantity of air and closed. The temperature was kept at 0° C. Any variation in gravity led to an alteration in the height of the mercury column requisite to balance the pressure of the air. The alteration in height of the mercury was magnified 300 times by the use of two other liquids, one over the other, above the mercury. The junction of the middle liquid with the mercury was in an enlargement of the tube, and its junction with the top liquid, this junction being the one observed, was in a narrow part of the tube. The top surface of the uppermost liquid was also in an enlarge- ment of the tube. Above this was a vacuum. 142 REPORT—1886. The instrument did not give satisfactory results, and Sir C. W. Siemens was led to devise another form in which the weight of a column of mercury was supported by two spiral steel springs. If gravity increased the weight increased and the springs were stretched. An increase in their length was observed by a micrometer screw, the moment of contact being given by an electric signal. This instrument gave much better results than the first, but it would require much improvement before it could be brought into use for differential measures of gravity. The Committee will be glad to receive suggestions from any who are interested in the subject, and any design submitted to them will receive careful attention. The following conditions should be satisfied by the instrament :— It should be portable. It should be capable of use in ordinary buildings and under varying conditions of temperature and pressure. Effects of change of temperature should be ascertainable, so that they may be allowed for. The zero point should remain fixed if the temperature and gravity are the same. Tt should not be affected by terrestrial magnetism. It should give variations of +5¢555 im the value of gravity. Sir Wm. Thomson has favoured the Committee with the following account of a gravimeter, designed by himself, for circulation :— Spring Gravimeter. The following instrument promises to fulfil all the conditions men- tioned in the preceding circular. Its sensibility is amply up to the specified degree. It is of necessity largely influenced by temperature and it is not certain that the allowance for temperature, or the feeds which may be worked out for bringing the instrument always to one temperature, may prove satisfactory. It is almost certain, although not quite certain, that the constancy of the virtual zero of the spring will be sufficient, after the instrument has been kept for several weeks or months under the approximately constant stress under which it is to act in regular use. The instrument consists of a thin flat plate of springy german silver of the kind known as ‘ doctor,’ used for scraping the colour off the copper rollers in calico printing. The piece used was 75 centimetres long, and was cut to a breadth of about 2 centimetres. A brass weight of about 200 grammes was securely soldered to one end of it, and the spring was bent like the spring of a hanging bell, to such a shape that when held firmly by one end the spring stood out approximately in a straight line having the weight at the other end. If the spring ‘had no weight ise curvature, when free from stress, must be in simple proportion to the distance along the curve from the end at which the weight is attached in order that when held by one end it may be straightened by the sree fixed at the other end. - The weight is about 2 per cent. heavier than that which would keep the spring straight when horizontal; and the fixed end of it is so held that the spring stands not horizontal but inclined at a slope of about 1 in 5, with the weighted end above the level of the fixed end. In this position the equilibrium is very nearly unstable. A definite sighted . DIFFERENTIAL GRAVITY METER COMMITTEE. 143. position has been chosen for the weight relatively to a mark rigidly connected to the fixed end of the spring, fulfilling the condition that in this position the equilibrium is stable at all the temperatures for which it has hitherto been tested, while the unstable position of equilibrium is only a few millimetres above it for the highest temperature for which the instrument has been tested, which is about 16° C. The fixed end is rigidly attached to one end of a brass tube about 8 centimetres diameter, surrounding the spring and weight, and closed by a glass plate at the upper end of the incline, through which the weight is viewed. The tube is fixed to the hypothennse of a right-angled triangle of sheet brass, of which one leg inclined to it at an angle of about one- fifth radius is approximately horizontal, and is supported by a transverse trunnion resting on fixed V’s under the lower end of the tube and a micro- meter screw under the short approximately vertical leg of the triangle. The observation consists in finding the number of turns and parts of a turn of the micrometer screw required to bring the instrument from the position at which the bubble of the spirit-level is between its proper marks to the position which eqnilibrates the spring-borne weight with a mark upon it exactly in line with a chosen divisional line on a little scale of 20 half-millimetres, fixed in the tube in the vertical plane perpendicular to its length. The instrument is, as is to be expected, exceedingly sensitive to changes of temperature. An elevation of temperature of 1° C. diminishes the Young’s modulus of the german silver so much that about a turn and a half of the micrometer screw (lowering the upper end of the tube at the rate of 3 millimetre per turn) produced the requisite change of adjustment for the balanced position of the movable weight. About 12 turn of the screw corresponds to a difference of ;,,, in the force of gravity, and the sensibility of the instrument is amply valid for =, of this amount, that is to say, for s5qoop difference in the force of gravity. Hence it is not want of sensibility in the instrument that can prevent it measuring differences of gravity to yoq555 3 but to obtain this degree of minuteness it will be necessary to know the temperature of the spring to: within ,,°C. Ido not see that there can be any very great difficulty in achieving the thermal adjustment by the aid of a water-jacket and a delicate thermometer. To facilitate the requisite thermal adjustment I propose, in a new instrument of which I shall immediately commence the construction, to substitute for the brass tube a iong double girder of copper (because of the high thermal conductivity of copper), by which sufficient uniformity of temperature along the spring, throughout the mainly effective portion of its length, and up to near the sighted end, shall be secured. The water-jacket will secure a slight enough variation of temperature to allow the absolute temperature to be indicated by the thermometer with, I believe, the required accuracy. M. Mascart’s Instrument. In ‘Comptes Rendus,’ xev. (2, 1882), p. 126, is an account of a _ differential gravity meter by M. Mascart. He employs a siphon barometer with the shorter tube closed, and containing gas to support the mercury in the longer tube. The gas chosen is carbon dioxide, to prevent oxidation of the mercury. The column of mercury supported is 1 metre in length. A scale is attached to the 144 REPORT—1886.° tube, and a vertical image of the scale is thrown by a gilded surface so ‘as to coincide with the axis of the tube, and the level of the top of the mercury can thus be read off by a microscope without parallax. The height can be easily estimated with suitable illumination to ‘01 millimetre. The barometer is enclosed in a metal vessel filled with water and con- taining a thermometer reading to 3,°C. A variation of ‘01 millimetre would correspond to a change of less than half a second per day ina pendulum. The empirical relation between temperature and level of the mercury was determined by preliminary experiments at the College de France. In the same volume of ‘Comptes Rendus,’ p. 631, M. Mascart gives an account of observations which he made with this instrument at Paris, Hamburg, Copenhagen, Stockholm, Drontheim, and Tromsé, on the occasion of a journey to the north. The Copenhagen results could not be utilised through an accident. The four northern stations gave results which compared with Paris differed from the theoretical values by the following amounts :— dg ‘ = ze dlin mm. dn g Hamburg . : : § 2 — 00003 —0:03 | + 1:2 sec. Stockholm De eae — 00003 =703 | 4 ae Drontheim : : ‘5 2 — 00024 —0°25 |- +10°6 secs Tromso . ; : é a — 00007 —0:07 + Ta A, dg : where “/ expresses the error in g. dl expresses the error in the length of the seconds pendulum. dn expresses the error in the number of seconds per day. He suggests that there is a local variation at Drontheim, as the pen- dulum gives a variation from theory in the same direction, though only of half the amount. M. Mascart remarks that the only conclusion which he draws is that the gravity barometer is easily transportable, and that its precision is not inferior to that of the pendulum. It only requires observations of the level of the mercury and of temperature, and the installation can easily be made in the room of an hotel in less than an hour. M. Mascart has been kind enough to inform the Committee that, though he has published no further account of his investigations, he is still pursuing them. He has found a difficulty in transporting the in- struments since constructed owing to the breaking of the tubes by the impact of the mercury. He thinks, however, that this difficulty may be overcome. He is now observing with a somewhat similar instrument whether any . changes of gravity in the same place can be detected, using a column of mercury about 4 metres long, balanced by the pressure of nitrogen in the cistern, the nitrogen being at about 5 atmospheres. The cistern is about 3 metres below the ground. So far he has only detected an annual variation correlative with the continuous variation of temperature. He intends to register the height of the mercury continuously by photo- graphy. ON STANDARDS FOR USE‘IN ELECTRICAL MEASUREMENTS. 145 M. Mascart adds that he would be glad to advise in the construction of a similar instrument should its installation be contemplated. The Committee desire to be reappointed, with the addition of Professor G. H. Darwin and Mr. Herbert Tomlinson. Report of the Committee, consisting of Professor G. Canny Foster, Sir W. Txomson, Professor J. Perry, Professor Ayrton, Professor W.G. Apams, Lord Raytzten, Dr. O. J. Lopez, Dr. Jonn Hopr- KInson, Dr. A. Muirueap, Mr. W. H. Preece, Mr. H. Taytor, Professor Everett, Professor Scuustrer, Dr. J. A. Fitemine, Pro- fessor G. F. Firzceratp, Mr. R. T. Guazesroox (Secretary), Professor CurystaL, Mr. H. Tomirnson, Professor W. GARNETT, Professor J. J. Toomson, and Mr. W.N. Suaw, appointed for the purpose of constructing and issuing practical Standards for use in Electrical Measurements. [PLATES IV. AND V.] THE Committee report that the work of testing resistance coils has been continued at the Cavendish Laboratory, and a table of the values found for the various coils examined is given :— Legal Ohms. No. of Coil Resistance in Legal Ohms} Temperature Warden & Muirhead, 640 . (No. 155 ‘99872 11°5° Warden & Muirhead, 641 . £, No. 156 9°98404 11:25° [ee ee @, No. 157 1-00163 16°5° Biuart,6 . . . . & “No. 168 10-00642 17° K. M. oa “iy No. 159 ‘99729 12° Miiott,160 . . . G, No. 160 ‘99801 11° Rep IGIOT eee) a ¢, No. 161 ‘99791 11-4° Biotiei62 os. ¢, No. 162 -99877 11-4° Ti a ae ¢, No. 163 -99982 12°6° Pe Sia Mee). og! Yo Cy No. 164 9-98927 12°3° Warden,654 . ., C No. 165 -99936 121° se Ki No. 166 ‘99977 16-7° Jun ee G, No. 167 -99960 165° Mieott,169 . + . ¢, No. 168 9-9968 161° aa 1-2 Ki No. 169 9:9975 161° a ¢, No. 170 99-920 147° mamas 172 $F C No. 171 99-917 14:7° Miliott, 165 . . . ¢, No. 172 1:00003 17° 1886. L 146 REPORT—1886. Messrs. Elliott Bros. called the attention of the Secretary, during the spring of the current year, to the fact that’ in some of the coils the paraffin used for insulation acquired in time a greenish tinge, which is most marked round the interior of the case and round the places at which the copper of the connecting rods comes in contact with the paraffin. Careful examination shows this green tinge in almost all the coils, and an analysis of the paraffin made by Mr. Robinson, of the Chemical Labo- ratory, Cambridge, proved the colour to be due to a very slight trace of copper. The insulation resistance of several of the standards was, there- fore, tested by passing the current from 24 Leclanché cells through a high resistance galvanometer, and the coil from the case through the paraffin to the wire. This resistance for most of the coils tested was found to be from eight thousand to ten thousand megohms. One coil in particular, sent by Messrs. Elliott, in which the green coloration was most marked, had a resistance of 5000 megohms. Thus it is clear that the resistance. of the coils is not hitherto seriously affected by the presence of the copper in the paraffin, but at the same time it becomes necessary to watch closely for any changes which may occur, and to select very carefully the material used. There appears to be great difficulty in getting rid of all the acid employed in the manufacture of the paraffin. The only coil among those tested which showed an insulation resist- ance, so low as to be serious, was the one known in the Reports as Flat. When the galvanometer of 1700 ohms resistance was shunted with 4 ohms a deflection of 80 divisions‘on the scale was obtained. The same deflec- tion was obtained when the resistance in circuit was a megohm and the shunt was about 20 ohms. Thus the insulation resistance of Flat was only about + megohm, or 200,000 ohms. Two coils of special interest have recently been sent to be tested. One from Prof. Himstedt, of Freiburg, will connect his determination of the ohm with those made in Cambridge; while the second is a coil of 10 B.A. units from the Johns Hopkins University, which has been com- pared with the coils used in the determination of the ohm there. The results of the observations on these coils are, however, not yet com- pletely worked out. The Committee wish to express their sense of the great desirability of establishing a National Standardising Laboratory for Electrical In- struments on a permanent basis, and their willingness to co-operate in the endeavour to secure the same. The Committee have had under consideration the question of the means to be taken to secure the general adoption of the Resolutions of the Paris Congress. The Committee have received by the kindness of the French Govern- ment a specimen of the platinum iridium wire, of which it is proposed” that the French National Standards of resistance should be constructed. They hope shortly to make a series of measurements of its specific resist- ance and temperature coefficient. In conclusion they would ask to be reappointed, with the addition of the name of Mr. J. T. Bottomley and a grant of 501. e lV. Plat 856. 55" Repere Bt Asse is3 Liz Ss In the} ‘Association at temperat range of ter ‘The observ! Reports, an the previous from 11° to CHART OF THE VALUES OF THE LEGAL OHM UNIT RESISTANCE COILS & N°? 100,101. THE VERTICAL DIVISIONS ARE 000! LEGAL OHM. THE HORIZONTAL DIVISIONS © 2" CENTIGRADE hk 7 pe n 16 1S ” M1) 39881 5.815 Temyperature.cochiiient. 000259. 4 10/f) 297860at 10°98. Temqperature cochFiaent, CORT. Report on Proctual, Storudards tir use wv Electrical, Measurements. Lt g oae8 H 2 PEEREEEEENREEE ELH “Ss Hee | 8 EEE 8 q cot | 28 EEE EERE Eee yl AEEEEEEN EEE Bs A me ++ lati EEE td BN 3 }— rr — nes C Saguame 8 a Snot COON § Bt i J a sce rH AI aise i Seo a ACE F £9658. a € Bottirweeds ON STANDARDS FOR USE IN ELECTRICAL MEASUREMENTS. 147 APPENDIX. On the Values of some Standard Resistance Coils. By the Secretary and T. C. Fitzpatrick. In the last report the values of the Standard Legal Ohm Coils of the Association are given. For the one-ohm coils the temperatures range from 11° to 18°, while the coils of higher resistance were examined only at temperatures near 17°. It was necessary in all cases to extend the range of temperatures in order to determine the temperature coefficient. The observations were made by the methods already described in the Reports, and the values found are given in the following tables in which the previous results are included :— Resistance Coil, G, 100. Date Temperature Resistance Nov. 24,1884 . : : 11-4° : ‘99876 el 20. os i * i 11°6° 99888 Pecia Soe : : F 12°9° ‘99916 RE eeO! as : ; 4 1Sr52 “99930 Wee. 5b ;; é 2 F 13°5° pee eal = ioe 2 : ; 15°3° ‘99979 July 30,1885. : ; 17°2° 1:00027 oe ae - : ; 181° 100061 Mean value. ‘ : : : ‘999510 at 14:18°. Temperature coefficient . ‘ ‘ ‘000271 per 1° C. Date Temperature Resistance Noy. 21; 1885 cays. : is 99753 me 24 5, ‘ : 75° ‘99770 _~ pen ; ; ; See ‘99787 Jan. 30,1886 . ; ; 11:4° ‘99876 Nov. 30,1885. ; : 16? 99878 Jan. 22,1886 . , : 12°5° 99906 Noy. 30,1885 . . : 126° ‘99911 Mean value. : : ; : ‘998401 at 10°10°. Temperature coefficient . ; i 000274 per 1° C. Mean value of whole series . é - : : ‘998770 at 12°28°. Temperature coefficient ; 4 i , ‘ 000272. These results are represented graphically in Plate IV. by the curve ¢, 100, which is drawn through the means derived from the two series, and represents within the limits of accuracy of the experiments all the observations of the two series, the mean error from the curve, omitting one observation, being about ‘00002. In the diagram the circles indicate the observations of 1884-5; the dots those of 1885-6. L2 148 REPORT—1886. Resistance of Coil, © 101. Date Temperature Resistance ‘ Nov. 24,1884 . : : 11:4° “99813 Sepals ar : : c 11°5° 99815 Wiser 2.) Gs d : 4 12°8° 99847 Nov. 27 ,, : i : 12:9° 99851 Dec: ‘5! 7; ; . é 13°4° “99865 Age PATS : : 5 15°4° "99917 July 30,1885 . ; : 17:2° “99961 |» 2 4 . : 18° “99983 Mean value . 5 : : : "998815 at 14°15°. Temperature coefficient . ; : 000259 per 1° C. Date Temperature | Resistance Nov. 21, 1885 . : : G92 ‘99677 2h es § . : Tete 99698 Hoe ee : : - aig? “99704 Jan. 20,1886. ; - eS? ‘99793 Nov. 30,1885 . : ; 11°8° 99803 Jan. 22,1886 . q : 12°4° “99821 Nov. 30,1885 . . : 5 x 26° 99834 Jan. 26,1886 . : ‘ 2 el Bre ‘99868 ie Fe : : E ae 14:3° ‘99876 Mean value . : 5 F 6 : : ‘997860 at 10°98°. Temperature coefficient from this series ' ‘000272 per 1° C. On plotting these results it becomes clear at once that the straight line joining the means of the two series will not represent the results at all. The first series is represented by the upper curve ®, 101 (1), the second series by the lower curve Ky 101 (2). Thus it would seem that between November 1884 and November 1885 this coil had lost in resistance about ‘00015 ohm at a temperature of 12° C. Again, the two curves are not parallel, so that it would seem at first sight that the temperature coefficient also has altered ; but this infer- ence is hardly justifiable, for the experiments in series (1) cover the time from November 1884 to July 1885, the high temperature observations being made at the later date; if then during that period the coil was decreasing in resistance the temperature coefficient would necessarily be too low; moreover we notice that the observations for July 1885 do not lie very far from the curve which represents the results of the second series. We infer then that of the two coils of platinum silver made at the same time—two years from the present date—one G, 100 has not changed since that date, and has a value of ‘998770 legal ohm at 12:28° with a temperature coefficient of ‘000272, while the other has changed by . 3 Revert Brit Aseve MBG Plate V. CHART OF THE VALUES oF THE 10 LEGAL Oum Cons & N°> 102 anv 108. THE VERTICAL DIVISIONS ARE (00! LEGAL OHMS. THE HORIZONTAL DIVISIONS -2° CENTIGRADE ] at i rf 9.3600) ! If | col 9.97 1 F 49700) 4 9365 (8.39600) ‘ s é 7 9 70 i 1 15 1% 1 16 8 ” 8 we © 102 9:990597 at 12°83 C Tarp. cocftiaent 00289 per I°C.% 13 9.9897K ab 12°68 C Temp. wweftinent 003 i2pa tC, Patticrseds kC Lit, Landars Tlnsrraung Report on Practical Steridards tor use nLElecrical Measurements. ye ON shont 0001 atnre CO The fac ist of 100 manent stat Messrs. the abor viile in Ap From th sfall of “00 This co: in the Repe 6000 megob green colon sem, then, in importa changes by «G, 101) if there is for this fall The two ooe-ohm in in the table made of *t) 352 motres ON STANDARDS FOR USE IN ELECTRICAL MEASUREMENTS. 149 about ‘00015 ohm, and now has a value of ‘997860 at 10°98° and a tem- perature coefficient also of ‘000272. The fact that the temperature coefficient of iy 101 is the same as that of 100 @, would appear to show that it has now reached its per- manent state. Messrs. Elliott Bros. possess a standard ¢, 63, made at the same time as the above two coils which in August 1884 had a resistance of 1:00027 legal ohms at 18°8°, while in April 1886 it was found to be -99928 at 16°6° and *99992 at 18°6°. From this it follows that its value at 18°8° would be -99998, indicating a fall of ‘00029 in a year and eight months. This coil showed marked traces of the green coloration referred to in the Report, but its insulation resistance was tested and found to be °8000 megohms. Both the coils iy 100 and 101 show slight traces of the green colour; their insulation, however, is remarkably high. It would seem, then, that it is very necessary to avoid the use of newly made coils in important researches, and to keep a careful check on any secular changes by means of repeated comparison. We hope, when the permanence of G, 101 has been certainly established, to remove the paraffin and see if there is any change in the coil visible to the eye which could account for this fall in resistance. The two ten-ohm coils iy 102, 103 have also been compared with the one-ohm in the manner described in the reports, and the values are given in the tables below. These coils are stated by Messrs. Elliott Bros. to be made of ‘the same wire of platinum silver ‘015 of an inch diameter and 3°52 metres long.’ Resistance of Coil, ¢, 102. Date Temperature Value July 1885. : - : 168° 10:00210 cefm WERE : ‘ : 16°7° 10:00222 Bet os ee 5 : : 167° 10:00129 res. 13 : - : 16°6° 10-00103 March 1886 . : z 156° 9°99833 bri, ve se 11:9° 9:98830 a , - 2 : 118° 9°98797 Noy. 1885 . : ; é 82° 9°97711 ° mula : - ° icoe 9°97512 co) Sa : 3 2 6°5° 9°97250 Mean value F E : . 9:990597 legal ohms at 12°83°. Temperature coefficient . é 00289. This ise presented by the straight line (drawn thus - -- - - - on the diagram) &, 102, Plate V. 150 REPORT—1886. Resistance of Coil, ¢, 103. Date Temperature Value July 1885 . 16°9° 10-00202 ” m4 16°8° 10:00197 ” ” : : 16°65° 10-00130 ” 93) abe : : - 166° i 10:00142 March 1886 - ; : 15°6° 9°99815 ” ” . . . 12° 998767 5 5 : é : Tee 9°98692 Noy. 1885. 5 : : 8-3° 9°97479 mS Mein : ; 5 7° 9°97315 Ae aah fo . : : 6°5° 9:96975 Mean value . : ; ‘ : 9°989714 at 12°88°. Temperature coefficient : 00312. This is represented by the second line (drawn black on the diagram) @, 103, Plate II. This difference between the temperature coefficients has been checked by determining the difference between the coils at different temperatures directly, and the results of the comparison are quite satisfactory. The proportional errors of the individual observations are somewhat larger in this case than they were for the single ohms, amounting in one or two cases to ‘0006, or 6 in 100,000, but the accordance is perhaps as good as can be expected. The point of interest lies in the fact that the temperature coefficients of the two coils differ so considerably as ‘00289 and -00312 per 1° C. although made at the same time from the same wire. Similar observations have been made on the coils of 100, 1000, and 10,000 ohms, but their number is not yet sufficient for the construction of the curve of variation with temperature. These we hope to lay before the Association on some future occasion. Second Report of the Commiitee, consisting of Professors A. JOHNSON (Secretary), J. G. MacGregor, J. B. Coerrman, and H. T. Bovey and Mr. C. Carpmann, appointed for the purpose of promoting Tidal Observations in Canada. THE reply, last year, of the then Minister of Marine to the memorial presented to him by your Committee is contained in the Report of the Association, This year the Committee have again been urging on the attention of the Canadian Government the importance, looking especially to the needs of navigators, of systematic tidal observations at stations properly selected. : In last January a deputation of fifteen or sixteen—consisting of repre- sentatives of your Committee, of members of the Council of the Royal Society of Canada, and of representatives of the Board of Trade of Montreal, accompanied by Sir William Dawson as President-elect of the Association—waited on the new Minister of Marine (Hon. G. E. Foster), and subsequently on the same day had an interview with the Premier ON TIDAL OBSERVATIONS IN CANADA. 151 (Sir John Macdonald), at which other members of the Cabinet, including the Minister of Marine, were present. The memorial of the Committee was very fully discussed and favourably received. The Minister of Marine, after the interview, asked for further information on practical details. This, with the aid of the data obtained from the corresponding Committee in England, was supplied to him. The official answer was received in June, and stated that, ‘ while the Government is fully sensible of the importance of establishing stations for continuous tidal observations in Canadian waters, it is not proposed at present, owing to the large expense in carrying out surveys and explora- tions, to undertake the additional expense which would be involved in establishing the stations referred to.’ The surveys and explorations here alluded to are those in Hudson’s Bay and on the Great Lakes, and your Committee were semi-officially informed that, until these are more nearly completed, it is considered un- advisable to incur the expense necessary to accomplish the tidal observa- tions. The Committee were told, however, that ‘the Government is fully alive to their importance, and much indebted to the Association for having - brought the subject to their attention, and for the valuable practical hints given as to method and cost.’ ‘In the near future it may be able to carry out a work so necessary and useful to the commercial interests of the country.’ Under these encouraging circumstances it is thought advisable to re- commend the reappointment of the Committee. Report of the. Committee, consisting of Mr. Jamus N. SHooLtBRep (Secretary) and Sir Witi1aM Tuomson, appointed for the Reduc- tion and Tabulation of Tidal Observations in the English Channel, made with the Dover Tide-gauge, and for connecting them with Observations made on the French Coast. [PLATE VI.] Your Committee (having, through the courtesy of the Board of Trade, been placed in possession of the records of the self-registering tide- gauge at Dover for the four years 1880-3, and also having been pre- sented by the Minister of Public Works of Belgium with copies of the curves of the self-registering gauge at. Ostend) stated in their Report last year, that they had completed the reduction and comparison of the times and heights of high water and of low water during these four years at both places. In order to obtain a common datum-plane for the reduction of the different levels, advantage has been taken of the international datum, which had been established by the British Association Committee ‘On the Ordnance Survey of Great Britain,’ and which had been made use of by the British Association Committee ‘On the Stationary Tides in the ire Channel,’ in the reduction of the simultaneous observations taken in 1878. This datum is 20 feet below that of the ordnance of Great Britain ; and it is practically (on the assumption of an uniform mean sea-level at 152 REPORT—i 886. Dover and at Calais) 5°50 metres below the French ‘ zéro du nivellement ’ (Bourdaloue). Since the meeting of last year the Committee, considering that these four years’ observations would, in their entirety, form too large a mass for publication, decided upon specially preparing a more limited portion of these observations. After much consideration, as the records of the year 1883 appeared on the whole to be the most reliable and complete, selections were made of a fortnight before and after the winter, and also at the summer solstice, and of a similar period at the vernal and at the autumnal equinox in that year; those times appearing to offer most points of interest. The high water and low water observations during these four periods © are appended to this Report, as also a continuous diagram of the two sets of observations during one of the periods (the vernal equinox). It has been repeatedly felt by the Committee that there are many points of interest which present themselves in the four-year period em- braced by the entire records which are beyond the scope of the present Committee, and which would require a complete and exhaustive examina- tion of those records to fully disclose them. Your Committee, therefore, before closing their labours, would suggest, that, if the Committee ‘On the Harmonic Analysis of Tidal Observations’ considered the investigation of the tides of the English Channel to be within the scope of their inquiry, the present Committee would, with the consent of the respective authorities, be glad to place at the disposal of the Committee ‘On Harmonic Analysis’ the records of the Dover and of the Ostend tide-gauges; as also any further information in their possession. In the earlier stages of the work of the present Committee it was hoped that some of the records of the self-registering tide gauges on the French coast would have been included in the comparison of the various tidal observations in the English Channel. It was found, however, that the difficulty to obtain records continuously throughout the four-year period selected was very considerable. With the more limited periods of four separate months in one year the difficulty is very materially reduced. It is still possible, that a comparative record of at least one of these shorter periods from a point on the French coast may yet arrive so as to be presented with the other observations accompanying this Report. In conclusion the Committee request, that the thanks of the British Association be conveyed to the President of the Board of Trade, and to the Minister of Public Works of Belgium for their courtesy in placing at the disposal of the Committee the records of the tide-gauges at Dover and at Ostend respectively. Also to the several other authorities and private individuals, for the kind assistance they have afforded to the Com- mittee during the course of their investigations. 17 ug Report o MARCH 26 Plate VI ORDNANCE DATUM GREAT BRITAIN DOVER DATUM OSTEND DATUM INTERNATIONAL DATUM COMPARISON oF TIDAL VERNAL EQUINOX— MARCH CURVES OSTEND. 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B | 22-68 ‘MH §6-82 Ses OTST bone = 68-66 MT Oost | “ogy : “MT €8-11 WY OG | ZI oe AVH 8-26 | ‘WV SFO | I ae “MH 60-63 = OY OTe se AMT 8-81 SL | SGNN | “MT SSI | ‘Wa ogy | “ in & MSM | “AH e846 | ‘Wd 960 | “ : 91-66 | “MH 89-86 a ee OL Ah m GL-63 an oe . a ra “AT 89-TT ‘WY 38h | IT HY 20, re “ . . 5 “ . 4“ “ec ‘Wd ‘mgg "YE “MT 09-8 ‘Wd 82'9 ‘ | 3 ANN ae cal ‘W'd ed iu " mooW MON @ | TASM | “MH GF-LG 2 PTL * ‘< | 91-66 ‘MH G0-86 “ 08°6 { - . 61-63 pies $8.8 WY 129 | OL bn | "MT 88-11 Wy g's | OT os | MH LI-L3 Beare cf Sargee | ey i “MH €9-18 One: WS i Zz CO) Aur104g € MSS “MT 89s. | ‘wa Fag | “ £ FA "MT €0-31 | ‘wa og¢e | “ - 4 01-6 Te Boe a he at bi i 99-66 ‘AH GS-16 ba: CLG 2 - ‘MH 26-93 % ae iY i ve eae al one Q - i CO) Aua104g FASS “AMT seer | Wa ere |.“ . ¢ ASH “MT F-3l | ‘Wa ere | “ 5 9§-63 AH 80:93 a SE On - 81-6 “MEL 83-96 4s 66 | “ . S ee ee WY noe 8 ¢ “MT SE-ST ‘Wv 1T3 | 8 33 3.96 G ‘MH 8F-93 oes SRR a it Ta "MI L9-¥1 Wd Te7 | s - € ANG ‘MT 88-81 Wad got | “ a | 81-63 ‘WH 11-93 eae er Go alee + 08-63 “MH €0:13 ce Cee ae 4 a “MT 00-ST Wy. oy 7 e “MT €8-F1 ‘WV ST | 2 4 z | €0)4uI09 | TMSS | ‘MH Gore es “Ore ip i cMN | “WH | C098. 1°" “Oey |\* ¥ H 81-66 ‘MT G6-F1 ‘Wd FFE | 9 Loquoooq 91-66 “MT €0OFI | ‘Wd QT | 9 «Aaquiacog ; 2 é yeas qoos Q | ee SE SS | | ee ee a ore Urey “4 2 UreyLtg "3 99.10J-pUuL 9010, : x re I9}0U0. ee soUBUPIO Cavour a = aaa souUvUpld, (avout { Lorn pam MOTO “}F OZ} WoIMuUaeTy ) ayeq a MOTAG “45 0Z| YoLMueary ) 9y8q = unyeqd oully, : WNYe (TL, Out, syeu8y bla uo 34310 HS Hie: uo 44910 : ANDLSO aaAoq wee vr 8 a es "SSSI ‘F Arenuee 09 ‘ZggT ‘2, IaquIe09q—"MOILSTIOG UALNIM “puoysO 7B pue Iea0g 48 seamo asnVs SuLI9ysS1991-Jos MOI, USYeY ‘104VA\ MOT jo pure Iay2M\ [StH JO SOUL, Dy.) ee eee 1886. REPORT 154 “WCHL 00-96 ‘iomammel A She TH: “MT 96-ST Wd eT F0-08 ‘MH w ‘WY “MT oe Las “AH ce ‘Wd 96-66 “MAT % “MH GL-96 WY 669 “MT 08-61 eRe es “MH 89-96 SD OILS 9) ‘Wd “UG§ “UF 10-06 “MT S661 vy SOLD raqrenb ysatq C “WH LL-96 WV L1GF “MT €8-81 ; eHOr FUSu “MH GL-96 nd Gif 60:06 AAT 19-61 era AOI “AH GF-LG ‘WV G8§ “MT G6-FI of GG € MS “MTL 00-86 ‘Wd I8'¢ 68:66 wal oG-ST tae “WH 66-16 WY OFZ “MT 66-81 = 86 €as ‘MH LI-86 Wd 86 GL-66 “MT 00-8T oy? SSR “MH 00-86 WY 3Se1 “MT 03-81 eee EVANS Tass “MH 68-16 Wd €FT 19-66 “AT GL-G1 ee oes “ATL 66-16 ONG) Gell yoo} , Urey Ag, "34D he ooUBUpPIO (aout EeOr OF MOTO “IF 0G) Youattoary) IA0g ="q royIv9 | 2 ee awn, BYIVUIAYT ANTISC 97R(T “c 00-08 FMS E166 § MS ¥6-66 Tass 96-66 TONG F8-66 6 UN 69-66 F MSS 69-66 90.10J-PUT AA JOJOWULOIV 194A AA “‘panurquogIi—ANILSTOY UALNIA €8-81 aa 81-96 Wd 08g €9-61 eye Oleky 88-96 WY LPF 60-81 s 06 OT &1'G6G ‘Wd GP SP-6L £ 696 6-06 WY OF SL-36L e ST6 €E-96 ‘Wd 616 89-11 Sol ee9GB £696 WY G&G €6-6L . G68 £6.96 Wd 813 88-TI “s q'8 69-86 WY €&'T €6-G OL e G sy 89-86 Wd FIT 8L-11 % GUL 66-66 ‘Wy €F0 €¢-1T rs og'9 89-86 ‘Wd S€'0 €€-IT a 869 81-86 ‘WY 06'0 €€-II a 89 €F-86 ‘Wd G0 6a-LL ‘WY Gt'8 €6-86 ‘Wd SETI yong UIBIII “44 aouruplgo (uvaut MOTAq “IF OZ] TOLMueAL ) wnjyeqd oul], WO ISTO Hy MAAC ee “ “ oe “ a3 61 s§ “ “ce “e “ “ “cc ST i “ “ ce “ iia “ce “ec AT “ce “ “ce “ “ 9T i “ “ce “c “ “ee ii3 eT “ “ “ “ “f “oe “ AS ba isa “ eI ss Zl toqmaooq equ 155 ON TIDES IN THE ENGLISH CHANNEL, ‘squtod asor} 0} se Aq[ney A[jyUaeptad SeM jueuINIys -UL OY} FO UOT, -BIJSLSAL 9} SB { paysnaqstur aq, 0} amv “4QSTE 99 pue sg 92} 99M 4Oq y.‘SNT} poytem ‘s[OAST ‘MHL oAaod eu — ‘aN ‘Wd ‘WP YE uooM TINT O (0) Aut1049 ¥ AS 68-66 } ASS 18-66 L MSM 61:66 ZL MSM 69-66 & M €F-66 € MS 88-66 § MSS OL-0& Tusa GF -08 LT-ST LG-L6 LE-F1 LE-96 19-61 18-16 LL-¥I LL-LG 6L-ST LL-LG L9-§1 18-16 “yRoig 6F-S1 GF-86 80-F1 G6-L6 66-61 GP-L6 &&-ST 0S-96 G6-F1 19-96 O9-§T 09-96 66-61 68-96 GPFL “ ‘WV “ec ‘Wd “ ‘WV “ec ‘Wd “ce WY “oe ‘Wd “ ‘WV “ ‘Wd “ ‘NV “ee Wd ‘NV oe ‘Wd “ee NV “ce ‘Wad “ ‘NV “ee Wd “ec ‘N'V “ ‘Wd se ‘WY “cc ‘Wd “e ‘WY fOr OS's 8F'6 Olé 8F'6 8E'S 89'8 08'G o'6 1G 9€'8 LOT GG “ &G oe oM 61-66 Z MSM OL-66 ¢ MSM 91-66 F MSM 99-66 9 MSM 96-66 § MS 99-66 F MN 61-66 g MN 09-66 7M &8-66 89-81 " —— ‘NV SL-61 ¥8E-96 Wd 89: TI 2 488-06 WY €G-61 is 86-96 ‘Wd $11 = ¥EF-9G ‘WV ¢F-11 - €8-96 ‘Wd SLIT WV 69-66 SL-ZI Wd 88-96 a SL-31 Wy 89-86 i 8L-11 Wad 88-1 s 86-01 ‘WV £0:63 s $8-11 ‘Wd &8-66 - Heat ‘WV €E-86 e €9-Z1 Wad 81:86 3 €0-61 ‘WY 60:86 a SF-o1 Wd G6-18 5 GE-8T WV *88°96 Me SEZ Wad ¥89-9 88-21 ‘WV 8L-S6 3 &6-3T ‘Wa &&-96 FEL STG aw) go'T OL Ort 18°9 0G 169 oro 99 86'0 09 aa org OF TL eg CTL 69°F ol 98°F rauty GOP GF'6 OF 09°6 865 99'S Gls tF'8 TVS 6e'8 OG ors 86'T og'L 89°0 arg 0¢'0 8F'g 0& 1886. REPORT 156 CO pure -q) Auu10}9 Co pue ‘q) AuII0}9 ‘Wd “WU0¢ “UST Joqyienb ysvy ) pue}so='0 wA0g ="q SIV & MNN 81-66 ¢ MN 96-62 & MSM $866 @O10J-PUT AA To}OMOIVE —— JOT}VO AA 16-86 “ACH “MT “MH “MT ‘MH “MT ‘MH BST bo ‘MT 6o-FL ‘Wd OLS = 9N “MH 18% 7 HLg0L 3 ie 68-63 “MT LL-ST ‘WV STS L ‘MH LT-66 Gaol: i 3 GN “MT L¥-1Z ‘Wd 61'F 9 yoreyy FLO “E881 ‘F IMdy 03 4 yore[—XONINOY TYNE A ‘MH 19:43 “ce 8Ee's “ec “ “MT 19-41 Wd ere | “ os Ta ‘MH LI-¥6 Pam fel ta s &3-0§ “AT L9-ST Wy ole | Ff ‘MH LI-GS een Secure Irie e “MAT LL-OT side cale eine ss F MN “MH 16:93 me GE9. *|| EE e &6 6 “MI LG-81 WV ¢g0 |¢ = ‘MH 11-96 ee 16FEOL ass 3 9 MSM “MT LP-9T Wa 70 | “ e 91-66 “MEH 19.96 WY F269 | @ - “MT LE-ST 4 SOR TEN |x ot “MH 18.93 ‘Wd rate] “ “ “MT LI-ST soe Sy a a : g MS ‘MH 19-96 WY CFP | se 9 HN “MT 88:8 Wd JTL FUN “WH 18-83 ‘Wd OT - ss 18:6 ‘MH 88-08 < #91 91-63 “MT L0-11- een yy e “MT 86-2 WY OL “AVH LL-LB ‘WV Fo'0 Ok es “ACH 8F-0E = 9GaiD “AT 69-LT “ ¢9°9 ns 90 “MT €9-8 ‘Wd Ge'9 ‘WV ‘WIE ‘UF | + ANG ‘MH GL LB ‘Wd $970 ¥ ‘* 06-63 “MH GF-66 Si Onisl uoouL MON e@ 68-63 "MT 10-11 “ ee'9 “ eo . ‘WV Z19 ‘ME 19-16 ‘WV 30 6 a “ 9601 “MT LEZ Wad 69 we Ys € a “Wd 69'¢ , € UN | “WH Z0-83 gears || 69-6 “ slor Sek tToer | tan rier umuwore | | | WY z7¢e'C REPORT—]1 886. 158 CO ¥ a) Aur10;g CO ¥'°q) AuI0j4g CO x") Aunt04g ‘Wd ‘Ug "49 woot [ug O CO x ‘q) AtmaI04g CO) Lun1039 CO) Ata104g f pa2380 ="0 U waog= a SYIVUYT “ “MT 68-21 Sega €MSM | “M'H 18.86 wa-ept | " 11-66 “M"T ZO-FT SeeGe he | va oe “MT 1-63 mV 190 | 92 ie "MT 1¢-91 “ CL “ iia €MNM | “AH 19-86 ‘Wd 69'0 z § 16-63 “MT 19-61 ie Aig? . ¥ “MEL GFL ‘WY 610 ¥G s "MT LGZI ealy'9 “ ‘ 7 UNG “MH 19.9% ‘Wd 82'0 k as F108 “MT 19-21 SESE Oy x . MH L-92 WV $0 | & i. 8 ANG “MT 10-61 Wd €Z9 | “ ie 90-08 "MH G8-GZ SECO TT mes E “M1 GL II OVE AO IGG S “MH LE-9G &é Of TI “ “ee € ANG “MT LY-ST Wd 0'9 ss L £9.66 ‘MH 66-93 ot al § "MT ‘WV €€'¢ 1 “MH “ec SF OL “ce “ t 1a “MT Wd ag ae “ee $962 “ATL “ee ST OL “ “c “MT ‘WY OFT | 02 en ‘MH oe O'OT “ “ € ASH “MT We BG ll ee ti GL-6G "ME ee = aio ed ys “MT WV She | BI Yyoury Re Urey 94) Bienen eouBUpIO (Cavour . MOTO “94 OZ) ToLAuep.r) ) aed TOIL AA ae wed ouwry, ANDLSQ 9010J-PUL AA RCHOIUCNT Sf TOV AA $¢-Z1 0-08 LT Ge (8 8-21 S1-63 €Z-01 €1-63 €T-01 SL-LZ 8L-6 EL-8S SL-O1 GE-13 €LO1 88-16 SLIT 88-12 8L-1I 69-16 23-21 8h-9% 88-IT £-9 81-31 89-43 0-21 qa0y ure “39 aouvupl(d MOTE “IF 06 wnyeqg UO 4FY.S1OFT ‘Wd F621 “ 69° IL wy gL “ $811 ‘Wd T¢°9 “SAGSHEL ‘WV 9€'°9 Saeco ‘Wd 269 “SF Tl ‘WV I1'9 “ LFOT Wd 6F¢ “ 0€'01 ‘WY FE'G ASOT ‘Wd G19 “ 0S'6 ‘NV GPP “ 626 ‘Wd 00'P “ CLG ‘WV 6F'¢ “ 78 Wa Oe «“ 9Z'8 ‘WV GPG (uvour YOLMUaAL ) our, “ce “ (ner oe “ “ “ “ “ ae “cc “ “ “ “ee “ ‘ ne! “oe “ee “ “ “cc “ Gk aCe “ec “ “ “ “ “ ioe « “ “ “ce “ee “ “ OG ie “ ii3 “ it3 “e “e GT Youre 978d “PanuyuwogI—XONINOT TYNUAA UTAOG 159 ON TIDES IN THE ENGLISH CHANNEL. ‘Wd “WTS “48 Iazrenb yseq ) Co ¥ ‘q) Aum1035 CO) Am04g (0) Aua104g CO x ‘d) AuI04g MPa T MSM 46:08 + Ee oe BF-93 ZL-FT Z9-6 16-81 LF-96 LEST LL-SZ 6-F1 L¥-¥G LUST 18°F Z9-FT L1-¥6 20-91 Z9-92 36ST 38-96 18-91 Z1-16 16-F1 69-86 BL-1T BE-FG LY-81 ZL-S6 Z0-ST 18-93 10-F1 19-18 Z6-E1 BL-1G 69-1 10-88 Z9:ST LL-8 Z0-F1 €6-66 Z9-F1 LV-86 ‘WY 02'¢ STOL ‘Wd FI ee. 8F'6 ‘WV 61° “e ZE'6 wa ¢e cin ASH?) ‘WV 183 Setar Wd 8G “ OF'8 ‘WV 683 OSes aa $e ee LS ‘WY 82" 9% “ 66 86 “ Tudy “e ec ce “ec “ “ee “ 6 “ “ “ec “ “ 6 “ “ce “ce “ “6 ce “ “ce 0-66 Z 89-16 60-61 89 96 €9-61 89-96 88-1 89-96 8L-E1 60:96 &3-F1 8L-46 60-F1 81:43 €0-F1 88-96 &6-F1 38°96 8E-F1 66-16 €€-61 8L-€6 8L-01 &F-96 SF-1T 68-96 6-11 §1-86 88-11 89-86 69.61 69-86 €T-1T 66-66 SLIT 81-66 ‘69-11 86-06 89-11 88:86 “cc 128 ‘Wd 91 “ FS ‘N'Y 8G ee ay Wa 22 a3 6L ‘WV 021 “ Ol9 ‘Wd F¢'0 ‘WY ¢GE'g = Lea ‘Wd 68°F “ Qvit WY OF “ 82:01 ‘Wd 0Z'¢ “ O10 wy ge “ec 66 Wad o¢ “ G2'6 "WV 86'Z “ G’6 Wd 0% “ 8g's ‘WV 8¢'T “ 9F'8 ‘Wd 93° “ 28 ‘WV Il‘ “ aI’ ‘Wd 8¢'0 “ 0's ‘WV 660 “ 6r'L ‘W'd §3'0 “ ee. ‘WV 610 1886. REPORT LGV wv VG. tmiben 160 “MEL VC cam wma Snipa “MT &3-F1 WV 030 | #1 “ T MNN “MT LE-9T ‘Wd 8¢'0 eae é€N ‘MH §6-93 ‘Wd 60g Megs 16-08 ‘ME GSS = 1g°9 Gee 18-08 "MAT 89-FT y age] RN i eA ‘W'd ‘WBF ‘YZ “MT 63: FT eV TO | st = | ‘WV Chie Joqrenb ysatyq C 7 MNN | ‘M'H 68-96 ‘Wd 8¢°¢ as CONE ‘Wd Seba Co) qsnoy 93.08 "M'T oL-FL "Gre ley; “> ie eOROE vs peat fs ‘MH LB-9% TEV 6:cy ten | | ‘WV ale 4 "MT Z0-FI “ce IIL ‘77 “ “c «“ “ EN ‘WH LL-9G ‘Wd 8¢'F aoe | + HN ‘Wad a aie 66-64% “MT 16-FT “ PP OL c “ } c0-08 So “ iia “ ‘MH LE-LE ‘WV 96'F | Sinem g Wy is es ‘MT Een Las oP OL 6e ee ie “e “ “ Tas ‘MH LE-LG ‘W'd 8f'¢ eet | TN Wd EN: 06-66 “MT 69-F1 ea OE eee | 66-66 e ae “WH 16-12 evs") | om i ‘WV Ole oe “MT 60-81 “ 8o'°6 “ a3 ii) “ ia} S MSM | (ACH 13-83 ‘Wd 26% ae line i Wd Ae 88-64 “MT 3-EE “ 02'6 “ “ | 18:66 “ “ “ ‘MH LT-83 ‘WV 69S ie ‘MEL 81-66 WY ool (eam “AAT LE-Z1 es S156 Nie Sse “MT SLIT ee oG.e Pe € ONG | ‘MH 16-8 ‘W'd €3'S eset CUNT | ‘MH €8-08 ‘Wd 89°0 eae 61:62 "MT 14-81 “ Tes “ ia) 1 81-63 "MT €¢- TL “ tS “ee oe ‘MH GL'8G WY $% Gt oc SE ‘MH 89-08 ‘W'V 680 gPace “MT 19-31 BS RS sake pas € ONY “MT 88-01 ce eeijatza, rae Sod € ON ‘MH LG-86 ‘Wd 8¢'T are. GL-62 ‘MH SL-1¢ ‘Wd F0 Sot eas TL-62 “MAT 10-1 earn cel es “MT 86-01 ‘WV GOL Ph CO) Ysnoy "MA 8-86 ‘WV TZ'T ede > UNG “WH €0-18 fein || ? ANN “MT LE-Z1 ‘Wd Gg’) 9 oune 18-66 "MT 89-01 ‘Wd OL 9 oune LL-66 ' yooy 4oay 9010J-pUt | Ureyig °34) : urBqiig "39 ican aoUvUpIO Cavaut | Soaeaenee aouvupIO Cavour { puayso="0 \ eee MOTE "95 0Z | YOUU. ) | fenmeed HE MOTEG “3F0Z | orMuaary) AO =" + wmnye oul | wnyje OulL (al IOYIVO AA oi eo hL | aoyqwo AA et THEME iL SHAVUOT ANGISO uaAod ES8T ‘u9g ATuP 07 WBZ oUnf—MOILSTIOY uAWiIAY 161 ON TIDES IN THE ENGLISH CHANNEL. LMS | “AV tele | ‘Wa see | © 1 || @ASM | “MH 8966 | Wadett | “ © 90-08 “AT LE-8I 5 ate tad £0-08 “AT ‘SF-LT * 93'8 eae oon ie WV as aed ae 89-08 WV FT ita % Jus, KOT SLIT ans Ue les seas FS ‘AH 19-12 Wd 99°T eee! ; MS "MH 81-62 ‘Nd 8¢'0 at 60-08 =| “ALT LL8T ees: . 0-08 | “ANT 8-11 py ae ieee ree AH LE-LG es de AH $663 | ‘WV 87:0 | & © poet | LAT | oRRRE | tego | Same eae eee aes 16-62 ‘MT 19.81 ae thy) re ees ar rit aor ne ei ({ ‘MH LLL] TOV. Sioa ‘MH EF-63 A SATs nate ‘MT | 20-81 Gath ah pe, 2 ems | MT | gtr | weer | « CO) ysnoy +OSS | ‘MH 416 | Walho | “ & 68-66 | “M'H 8F-63 Ap GeT | 6 ete boa he, Rees eae ee AAR Ra ‘AT | SOT | mvO8e | Ie 4 V4 . H EL-6 o GIT ‘ “ € MSM | ‘AAT LBS Ea 88 pet Sg PASM | “MT aia ‘Wad 99 Tee ‘Wd “WZE ‘YF 96-66 ‘M'H 60-13 ‘Wd $0 i 88-62 ‘MH 88-8 © grot| ce uooW 1M O ne Hae wy sei 08 4 “MAT 86-31 WV org | 03 “ $a "MAT L9-8T ‘Wd $L9 UE Ra ‘MH €9-86 ‘Wd 62°01 pene 16-66 ‘MH 19-93 COP Gai lili | cian aes a9 “MT EF-31 ‘Wd 9Z'9 2rd es “M1 66-1 WY a9 | 6T 06-63 ‘MH EF-83 Pe Oba Gh ae ote 3 MMS “M < U'd 8€" i ta ‘AVI £86 BoGeainae ie 86:66 MH ae : GMS | ‘MT OPEL. -|- LOR Re “AT LOFT wv 99 | ae 16-66 ‘MH §0-86 “ 4s'6 oo WH 19-93 eo “ANT 89-81 WV el> | st “ “MT 4 9) | MH €0-86 Ce oe Au | AbRGe) | gee hee? x sMSM | ‘MT | eo7r | waeoe |“ & ra a sua wv pl i as 66-66 ‘M'H Eh-1B “Ors ey , ¢ ; "i a ‘N'Y Tal _ fj “ ¢ MSM “MT LE-OL ‘Wd 8P'S eee ip Hae #! ie ta 81-63 ‘MH 11-92 ae 82'6 ‘a G MNM “MT €P-1 ‘Wd ¢9'% pe - i pe WV ane ae 81-63 ‘MH 89-92 ES jae i . re ’ ‘NV GZS ( “ CO) qSnoy €MSS | ‘AI eo, | ‘Wagrs | “© WH £0.16 . It ws $6-64 ‘AH LB-9B “MT €L-ST Ry eet | OF ~ ‘MH G0-96 nO i eat |= 30 ‘MH €3-86 “ 879 me Ne € Wf “M1 LY-F1 al a | 20-08 “M1 FEL ‘Wa 280 os 80-0 ‘MH GP-9G ‘NV 8F'9 , ae ‘MH E916 ‘WY ¥6 CCnm os “M1 L¥-S1 ‘WV §T Gave “MT SLL " oa anni “Mm H L1-9@ “cc 1¢'¢ oe “ee t MS ‘MH 2.86 ‘Wd OF’ F “ oe € ASS “MT 16-41 ‘Wd §10 Pag Pe 96:62 “MT 88-21 ae ie alle moe ‘MH 16-9% ‘WY If'¢ ia ‘MH G9-16 WY Bone se. “MT 18-21 O10) | 86 | ‘M1 $¢-31 Be weet Be . CO) ysnoy ‘MH GS-9 ‘Wad ¢¢'T patie: 7 ASM | “MH 9-86 ‘Wd OFS orn Vm > ‘Wd “WIRE “TL ¥ MSS “MT 18-81 oo STE Ah A 16:62 “MT €3°S1 H SEOT | be ora) zoqrenb qsey ) £0-08 ‘MH LL-9Z WY?TP | 42 ‘WH 88-16 wy oes | 16 * is “MT 69-61 ee SUT “M1 88-11 PP anol ie is | 7 MS | “MH 66-96 ‘Meee! |e ¢ MS | ‘AH £0-66 jwaege | | & Co) qsnoy 88-66 “M1 Z0-FI RHODE ce 81-62 “MT 3-21 ge Ae | is 4 “WH GF-LE ‘WY SVS | 98 | ‘WH 81-86 WV ers | 93 | eI “MT GL-Z1 apa | "MT 8L-11 S eeeri S act ‘WH | Gees | Waste | oy emi | Ae |, eaee | a Ga.| 98-62 “AT LL-ET ee 98-62 “MAT L-1T fr eiGiall So ‘MH LF-LB WV She ae . |. ‘MH €1-63 WVOST | 9% “ "MT LULZ ‘Wd ¢¢'6 | 72 OUNL “MT €L-IL ‘wad oFg | Fe ounr Joo} Joe} o1O}-DUr ureqig "3 Prats ureqitg "3 penile aouvupld (ue pea ee aouvupio (avout pue}s() =O } MOTIF 0Z | orate.) ) ayeqd phy ade MOTE "IF 0Z YoLMuear) ) aywqg TeA0g =" mnye oul mnye oul a="d TOYIVO AA me ce LL 1OT]}BO,\A Ee ae ML SHIVUIO YT aNaLsO aAAOG X MOS — 0 Na : nl *panuyuod-—GOILSTOS YAWWAS 163 ON TIDES IN THE ENGLISH CHANNEL. LL-FG ‘Wd 9T') cg £0.93 0% 10-9T eT 96:62 SL-9T 66-6 13-46 * 069 €0-SZ L¥-ST WV ¢¢'0 €8-ST € 49 LG-43 ‘Wd 8t'¢ €9 88-42 TL-0¢ LUST ee Fey 60-06 $0-ST LL-4G WV g¢ 89-93 ‘W'd “Wgg “T9 LL-FI © $211 €E-F1 Teqrenb qsinq © € MSM 00-2 ‘Wd 8¢'F GN $8.9 91-0 LL-FT “ 8c'OT FL-0 S6-F1 18-9 WV GZ'F $8.92 LLFT “ ¢P'01 8L-ST G MS LL.9% Wd gf} eM SL-L1Z 96:66 16-41 “ Slot 06:6 SL-ST L193 ‘WV SF 88-23 LG-F1 “ 89'6 SL-8T G MS 10:12 Wd 9Z'¢ F ANAL 89-82 (0 ¥ 'q) qSnoxy 06-62 LL-FI x E08 68:62 £0-8T L¥-1 WV 61'E $0.86 € MSM L3-ST eee eM 89-11 60:08 LL-9Z Wd 98° 90:08 88-86 GL-ST WV €1°6 | 9 tequiaydag 86-11 "E881 ‘F 10q04990 09 J roquieajdag— XONTNOI TVNWOLAY v| “ACH €0-0E T MSS “MT LL-GI ‘Wd oy € MS “MT 86-11 26-62 ‘MH 18-16 ~8ei0 €6-62 ‘MH SF-08 “MT LUST “ 69'9 “MT SLIT ‘MH C616 "W'V €T'0 ‘MH 88:6 ‘W'd ‘wg “YE F ASS ‘MT G9-Z1 ‘W'd 8t'9 TMSM | ‘AT 83-11 Uooy] MON @ 98-62 ‘MH 16-16 ori 98-63 ‘MH €1-0E “MT LEST ‘NV 9°9 “MT 89-11 ‘MH LL-LE Sa S Gull ‘MH 81-66 €9 “MT LI-ST Wd gf'¢ T AAS “MT 89-11 16-62 ‘MH LE-LG “19°01 66-66 ‘MH SF-63 ‘MT 19-81 ‘WV ggg “MT ST-31 ‘MH LG-LE “OF OT ‘MH €8-62 ac ‘MT 19-81 Wd o¢ Ta ‘MT €8-61 FL.0 ‘M'H B8-93 “ 06'01 GT-08 ‘MH ae go. . Use 5 GP-ET 3 “ 0'6 OC ORress Arie 1886. REPORT 164 ‘Wa ‘WTF ‘UG uoow [uA O puso = ey I0A0g =" SyAVUIOAT ‘MH $6.0 SS ae “ “ “ T ANA “M1 80-6 ‘W'd cL T ANN & ‘Wd : s 66-08 ‘WH €9-18 “ 98'IT 93-08 g “AT 8L:6 ‘WV €9'9 rr ‘WV 81 ne ‘M'H 89-08 aed 3 ee = IGN “MT €3-01 ‘Wd €¢'9 T ANN ‘Wd “ “ 1Z-08 ‘MH €0-T “ SF'OL 63-08 “MT LL-@1 ‘Wy ee'9 | LT e “MT €3-01 ‘WY 99 ‘AVH L183 LB ee ‘AH 60-08 “ #801 07% “MAT 16-11 ‘Wa Teg | “ oS T ANN ‘MT SL-01 ‘Wd GHG F1-08 ‘MH LL-LG pee) DN | ae 2 F1-08 ‘MH §1-0€ | > {S01 ‘MT LE-8T ‘WY SF | 9T £ ‘MT 86-01 ‘WY 169 ‘MH LLL] SSE. |, “ ‘AH €E:63 “ 69°6 T MSS “M1 19-81 ‘Wd gg'g | “ * oN ‘MT SL-IT ‘Wd oop $6-66 ‘MH 66-93 Ee age oe | 66-63 ‘MH $1-63 © Gab "MT L0-¥1 WY O° | ST i ‘MT €3-61 ‘WV §8'F ‘MH 10:16 Py Otel] s "MH EE-8Z “ 527671 2s 5219-4* 2s 52718 4s 5211°2 6s 5258°8(b*) 5265°7 b 5208-0 6b,.,” 5259-4* 2s * Double. t+ A mass of fine lines. Dipymium CHLORIDE (ABSORPTION). Bahr and Lecoq de Intensity and Bahr and Lecoq de Intensity and Bunsen Boisbaudran Character Bunsen Boisbaudran Character 7430F 4 [ 5750 5TATT ae] 7220 € | 7360F 6 fo 5730 U719F 9s 7307T 8 5300 5312t 3b, 6894} 4n B 5230 B | 5219F 10b,° Pe 56730 06792F 7b, { 5500 5205F 9b, 6720T In 5170 3b, 6363 2n 5100 3 eee 6b, 6280 6282 in 5010 5087+ 3b, 6220 6225 3n 4810 74822* 8b, 5920 5962* 3b, 4760 14758 5b, 5820 5885* 3b, 4710 (4691* 8b, a{ 5824F 4b, \ b,,” 4618 1b, a. 5788t 10b, 4440 nit441* (2) 4275+ 3b, Bahr and Bunsen 6730 6600 6500 6360 5501 B5440 5390 * ‘Praseodidymium,’ ¢ ‘ Neodidymium ;’ von Welsbach. ErpiumM CHLORIDE (ABSORPTION). Lecoq de Boisbaudran 6985 €6837 6670 B6534 6492 &6404 5490 5433 85409 Intensity and Character 1 6b, 4b, Bahr and Bunsen a5230 54900 4539 Lecoq de Boisbaudran 85363 5278 a5231 5208 5189 4921 yA874 4855 4515 Intensity and Character 182 REPORT—1886. IopinE (Apsorption). Intensity Morghen Thalén and Morghen Thalén Character 6799°4 6834-0 3BbY 5732°3 57380 6778-0 3b 5719°3 5721°5 6741-2 6739°0 3bY 5713°8 57135 67240 2b° 5693-4 5707-5 6686-0 6685°0 3bY 5686:2 5683-0 6647°5 2bY 5664-7 5675-0 6638°3 6634-0 3b* 5656°4 5653-0 6594-0 2b* 5636°5 5644-0 6587:5 6582°5 2b* 5625-4 5625°0 6544'8 6541:0 4bY 5610-0 5614-0 6532°5 2b’ 5597°5 5597-5 6504:2 6503°5 3bY 5582°3 5586:0 6494-7 6493°0 4bY 5567-0 5571-0 6458-2 6455-0 4bv 5554-2 55585 6448-6 6446°5 3bY 5540°6 5545-0 6407°9 6407-0 4bY 5531-0 5531°5 6400-6 6399°5 3b’ 5514-8 5521-0 6365°5 6369°5 2b* 5506-4 5505-5 6559-4 6361-0 4b* 5488-1 5496°5 6354-0 1b 5480°5 5480°0 6321°7 6322°5 3bY 5462°3 5473-0 6313-2 6316°0 3b” 5457°6 5455-0 62741 6276:0 4bv 5449-5 6267-2 6271:0 3bY 5436-4 5432:0 62320 5bY 5412-0 5409-5 6229:2 6227°5 2by 5389-0 5388-0 6190:0 6bY 5366-4 5366:0 6187-4 6186°5 2br 5344-6 53460 6148-6 6148°5 6bY 5324-4. 5326-0 6147-0 1bY 53043 5307-0 6108-3 61100 Tb¥ 5284°8 5289:0 6069°5 6068-0 TbY 5267-8 5272/0 6031-6 6029-5 8br 5251°3 5254-0 6011-0 5235-7 5239:0 5991-4 5991°5 8b 5219-9 5222°5 5969-0 5206°6 5208-0 5951°8 5954°5 TbY 5192°7 5193-0 59318 5180°2 5181:0 5918-0 TbY 5165°3 5168-0 59150 59160 1bY 5152-0 5155-0 5898-4 5140°6 5144-0 5883:0 6bY 5129°8 5132°5 5879°5 5880-0 lipy 5120°5 5122-0 5864-0 5111°7 5112-0 5848-2 5848°5 5bY 5101-8 5102°0 5843°3 5845°5 1bY 5093-5 5093-0 5816°5 5816°0 5b* 5086-6 5811-0 5811-0 1b* 5079°1 5808°5 1b¥ 5072-0 57862 5784-0 4by 5064-4 57785 57765 2bv 5057-0 5759-1 5772°5 2bv 5050°6 5749°8 57530 3br 5044°8 57448 5745-0 5b 5038-6! Intensity and Character 3b. 2b* 6bY 4bY 7b* 5br TbY 5bY 6br 6bY 5by 6bY Tbr Tb” 4bv 8br 3bY 8by 3bY 9bv 2b* Tb* 2bv 7b Tb* 6bY 6bY 5by 5bY 5bY 4b* 4bv 4bv 4bv 4bY 3bY 3by 3by 3by 3by 2bv 2b 2bv 2bv 2bv 1b ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS, Roscoe and | Thorpe 64751 64429 64213 6383-7 6372°6 63249 6318°0 62668 6216°9 61815 61679 6155-0 6122°6 6112°8 6079°2 6071°3 6040°9 Hasselberg 6853°7 6827°5 6808:7 6794-0 6772°5 6766'3 6742°4 6734-6 6725:8 6710:7 6695°3 6689-0 6678°3 6658'9 6558-0 6552°7 6546-0 6526-0* 6515°6 6509'8 6502'3 6488°5 6474-7 6468:1 6461-0 6454:8 6448:2 6438:2* 6433-2 6424-7 lopine Monocutoripe (ABsorPtion). 183 Intensity || Bescostanl Intensity Resdoatand Intensity || Roscoe | Intensity | and || Th and Th and and and Character orpe |Character orpe |Character|| Thorpe |Character 3bY 6033:2 3bY 57820 4bv 5552°9 3bY 3bY 60213 4by 5751-0 3bY 5535-4 3b” 3b” 6005-2 8bv 5744-4 2by 5523°6 3bY 3bY 5995°9 4bY 5719°6 8b” 5508-4 3br 3b’ 5974-1 4b¥ 57130 4b* 5501°3 3b” 3bY 5957°3 8b* 56858 3bY 5482°5 3b’ 3bY 59443 4b¥ 5679°5 3b” 5459°5 3bY 3bY 5918°7 3bY 56583 3b” 543571 3bY 3bY 5905'1 3bY 5650°0 3bY 541271 3b" 3b” 5886°7 3by 5632:1 3bY 53943 3b” 3b” 5877°8 3bY 5628°6 3bY 5368-1 3b” 3br 5861°4 3bY 5618-4 3bY 5349°8 3bY 3b” 5852°3 3b* 5600°7 3bv 5330°0 3bY 3br 5843°7 3bY 5590°0 3bY 5315-5 3b” 3bY 5820°5 8by 5572-0 3b” 5295:0 3b¥ 3br 5815°9 4by 55613 3b” 5276°1 3b” 3b” 5788°8 8bv Nirrocen Prroxipe (ABSORPTION). Intensity and Intensity and | Intensity and Chararter Hasselberg Gharautex fasselberg stirs 4s 64173 4b," 6186°6 1s Is 6412-1 Is 61758 61-3 2s | ‘ 6407:0 In 6171'8 4s Arp) is 6397°5 Is 6165°3 6b .3” 2b5., 6377-7 AD) .0 6164-7 8b. 4s 6367°2 2n 6160°6 4s 2b 6360°1 4b. 6155°5 6n 6n 6353°3 2s 6141°3 6bY 4s 6350°9 in 6136-2 Abo. 2s 6341°0 2Do-2 6126°4 12b,.4 4by.5” 6334°2 4D .0 6121:2 8b,-; PP 2n 6321°5 4s 61146 6o:5 Abo-s 6316°3 4b, 6110°0 2s 2s 6311:2 t 6107°8 4s In 6305°1 1s 6090°4* 2s Is 6297°8 Is 60843 4s In 6290°0 4n 6079°2 2s Is 6268°7 Is 6068-0 2b 2s 6263°4 4s 6055'8 6s 2s 6259°2 2s 6052°3 Abr 1b,-4 6255'8 As 6039°4+ Wo.6 2p.” 6250°7* 6s 6028°3F Wy , 6b,” 6242°3 2s 6023°3 4s 6Do-5 6236°7 6s 6018°6 6s 6b 1 6232°3 4s 6016°0 1s 2b. 6224°9 4n 6013-4 6D 0 Abo. 6212-2 May 6002-5 6b,” Is 6206°3 ab 5997-1 6bo-3 4s 6201°5 6by.5” 5989-1 ADo.g 4n 6194'8 2Do:3 5984°6 s * Double. + A mass of fine lines. REPORT—1886. 184 NITROGEN PEROXIDE (ABSORPTION)—continued. Hasslborg | Mopnenceer'*| Hasselberg |" Gpuagdat | Hassetberg_ | Tuensity and 5977°5 Abo. 5642-1 10b,.,J 53491 Is 5972'6 4s 5635°7 8bo-2 53454 4s 5969'3 2s 5633-0 shez 5343-0 6bo \ip 5962°2 6n 5627:9* 2s 5342°5 ee vs 59570 As 5624-0 4s 5339°3 8by., 5947°5 4bY 5616'5 1bo.4 5336°0 isi 3. 5944-8 6 bo §5610°1 Is 58341 2b. 5936-0 6b .0 *5606°4 Is 5332-4 6n b 5933-7 6n 5602'1 Is 5325°1 6s | Ps 5928-1 10b,.2 5600°2 4s 5321°6 4s J 5924-4 4s 5588°0 4n 5312°8 eps b 5920-4 Bhs. 5579-9 6n 5304-6 6,6) E4 5915°3 6D 4 5572°5 Is 5294-0 4b, . 59126 6b, 5564°6* 4s 5288-2 6s 5902-7 6b, 5564-5 1D t 5285°6 6n |, 5898°3 7s 5557-0 4s 5279°8 6b,., [22 5892-2 6b,.5 55535 - | 4n 52778 4s 5877°9 4s 55509 4s 5273°0 Ab 58732 In 5542°8 pirat 5270°7 6b,.5" 5864-2 1h," 5540°3 beet } 5263'6 10b, ; 5859°6 bis 5537°8 1b, 5259:2 Sn b Dog 6853°9 6n 5530°5 8by..” 5251°3 12by.5 5850°5 sin} 5528-2 8b,., 5242-8} 8by.5” 58452 4s 5522:2 GbjeY 5240°2 8s 5840-4 1s 55161 1b,.; 5229°6 8s } 5837:0 6s 5502'5 4s 5224-1 8by.5 5828°7 In 5491°5 6n 5219:0 8s 5819-0 1s 5489°7 8b,.0"| p 5214-8 BB 5814-4 1by." 5485°3 Abt PS? 52070 10b ., 5807°5 Is 5480°8 4n 5199-9 6bo.5 | 5803-0 1b,.s 5476°5 4n 5199:7 10s 5791°3 Tb... } 5471-4 65-4 5195-0 10b,.. 5789°8 8s 5469°0 6n 5190°8 10b,.3" 57767 6s 5465°9 4s 5185-5 4b,., 57702 6s 54624 8br 5178-4 6b," 5768°1 is 54512 8n 5176°5 4s B752°5 8s 5448-6 1s }b, 51721 6D ps5 5747-8* 6s 5440-2 4n 5164:0* Is 5742-6 In 5432°9 2bY 5157°1 Is 57371 4s 5430°3 8s | nine} sf ‘i 5734-2 1s 5428°5 ADo.4 5154°6 s 5729-4 8bo.5 5421°8 4s 51450 In 5719:8 4b, [4 5421'8 ADo gt 5137:1 2br 5709-2 Shr 28 5420-0 68 Dog 5124-8 2b,., 5708-2 4by.0 5417-5 4s 5124-0 8by.1 5706°4. 6b,.3 5415°7 2s 5122:0 2s Dy 5699'5 4bo.3 5411°6 Is 5121:2 6s 5692:3* Is 5404-7 2s? 5119-4 4s 5689°3 4s | 5399°5 4n 5117-5§ 1s 5689:3 1by.. 5392°5 Sbis 5111-7 6n 5683:8 4s 5389-4 8s 5103-7 Db aaak dese 5679°5 shabby 3 5387-0 2s 51007 1s 5670-7 4b,* 53843 8by., 5095-2 8by..” 5663°9 “Abs..¥ 5379-2 Sho 5092°9 4s 5653-0 8by.," 5376:1 4s 5089-7 Abo.) 5648-1 6s \, 5363-7 6b,., 5086-9 26h. 5644'6 10by.g | 2" 5360°6 4by., 5083°1 4D 5 * Double. + A mass of fine lines. § Triple. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 185 NITROGEN PEROXIDE (ABSORPTION)—continued. Hasselberg a ale ‘ Hasselber, § Monee 5076°6 4s 48434 4n 5073°5 1s 4841°5 4bp.5” 5066-2 6D peo 4839:2 §Do.0 5063-6 4D o.» 4835'8 2s 5061-2 6br : 4831-0 6b* 5045-7 10b4 } brs 4820-0 on 01 ze 5042'8 4s 4817:2 2n 5041-2 6s I» ; 48143 2n ee Le ay 4812-0 8n be. s 4810-1 6n 2 5032-0 8s, bp.3° 48072 4n 5027-2 10b,., 4802°8 4n 5024-1 4s 4797-2 10n 5022°3 2s }b, 47928 8b,.,° 5020 8 1s AT87°4 2s 5018'8 1s 4783°6 1s 5009-6 6bo. 47788 65. 5003°3 Is AT75°2 4Dp.o 5001-1 4n 4764'8 6b5.4 4998-1 2n 4760°3 4D. 4978-2 4n 4757-6 4)o.5 4974-7 2s 4753°5 6n 4965°6 10n 47466 Sia } 4963'8 sith 4744-7 4s 4960-7 6b,.3” ; 4738-4 6b,.,” 4953-9 6b,.1 47361 4b,.2” } 4946-2 8b,., 4731-1 6s 4944-3 6s |. 4728°1 4s 4941°7 Shp 22 4721-7 4bp..* 4937°8 6bY 4718:0 6s } 4931:3 eS eae = 4715-7 4b,.4° 4929-5 Abr} Pors 4714:5 4D eo? 4917°8 4n 4710-2 6Dy- 4915-0 6b,.." j ; 4708:1 4s 4912-0 2bp-3 4702:2 4by.,” b, 49077 4Dy.g 4698°5 2.3” 4903-0 Sbo4 4694-0 Dyes 4896-0 4bv 4687-5 Abo. 4891-5 6D -5 4683:7 4br 4885'5 Spee Deg 4679-7 10b,.; 4882:3 8b, 4675-2 4n 4874-0 1b ., 4665°3 6b," 4867-6 2n 4662°9 4n 4865:3 2s 4659-5 2n 4860-6 2Dg-g 4656°8 4n 4856-7 1s 4643°8 10b,.,” 4854-7 1s 4640°9 6b,.> bo 4849-9 Qby.3” 4630°6 6b," 4846-9 4b Serer ee ee Sk cS ee eo i a os I, Se ee ee 7 A mass of fine lines. 186 REPORT—1886. Porassium PERMANGANATE (ABSORPTION). Lecoq de Intensity and Lecoq de Intensity and Boisbaudran Character Boisbaudran Character 65703 7b,. «4861 3b, 05465 9b). 4694 1b, 85246 9b, 4543 1b, 5045 7b, PHOSPHORESCENT SPECTRA. YTTRIA. Intensity and Intensity and Intensity and Crookes Character Crookes Character Crookes Character 6675°6 2b 5790°8 1b, | 51778 1b 6629°9 2b | 5736°9 10b, ! 4932-0 4b 6475°6 3b, 5670-0 2b, 4824-7 4br 6209°5 1b, 5491°5 8b, | 4449-1 4b 6179°7 6b, 5399°5 Tb, 4323-0 4b 5976-2 1b 5373°3 2b, | ERBIA. Intensity and Intensity and Crookes Character Crookes Character 5564 +b 5318 5b 5450 3b : 5197 4b SAMARIA. Intensity and f Intensity and Crookes Character Crookes Character 6402 2b, 5976 4b, 6093-7 10s 5620 2b, ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 187 APPENDIX. HYDROGEN. (See REPORT, 1884, p. 390.) Compound Line Spectrum Hasselberg Eye Observation Photographic Observation Intensity | and Character 4497-5 4492-8 4489°7 44852 4476°6 4473-7 4466°6 *4460°6 4458°6 4456-4 4455°3 4452-6 4450°3 4449-2 *4447-2 4444-7 4443°6 44168 *4411-7 * Vogel 4459 4065, 4060. 4497-4 4495°9 4494°3 4492-6 4489°6 44884 4486°9 44851 4481-0 4479-2 4477°8 447671 4474:°9 4473°3 4470°9 4466-2 4463-1 4460°3 44582 4456°1 4454-9 44537 44522 4450°1 4449-1 4447-0 4444-6 4443-5 4449-2 4440:7 4425-2 4422-6 4422-0 4419-6 4418-7 4416-7 4411-7 4409-9 4400-2 4390°3 4388°5 4386'8 4378'8 4347-1 *4340°1 4338°3 4242-7 4235'9 4233°2 4232°9 4232-1 4226°8 WHEE EE RPE WN REED EWR DHE NEE Hew ewe ew i RED NNNWOONFREhYNH =] toh Compound Line Spectrum Hasselberg Eye Observation Photographie Observation Intensity and Character bole tol bol le 2o|~ WNNR ERE PWONWNWWWWNWOArNNeERWwWwWde £0] bobo} lh ILS BN Aland lB rl dal Adal oll ala , 4448, 4413, 4340, 4220 4210, 4201, 4195, 4193, 4174, 4168, 4158? 4152? 4101, 4067, 188 Positive Band Spectrum REPORT—1886. NITROGEN. Positive Band Spectrum Intensity Intensity a and 6 and foe: and Hasselberg Character see and Hasselberg Character 6621°8 *6622°-4 4 6440°6 64395 Qu 6618°7 = 6437-4 1: 6615:7 1 64343 1 6614-2 6612°9 3br 6429-4 1 6606°7 2 c 6427-1 1 6603°9 ls 6423°5 1 66014 14 6422-2 1 6598:7 11 6419°5 Zz 6595°4 13 641771 1 6594-7 6593:1 3 6414-4 2 6590°6 i= 6409-1 1 a 6587-4 9b 6403'3 1 6583-0 6400°6 1 6580°1 25 6397°5 1 6577°3 1! : ee eas pea) ie = 6385-8 1 aoa! : 63848 6383-5 4 pee i 6378°3 12 abbas 2 6371-1 1 6555-2 15 6369-9 1 ae : 63668 63678 3 6548°2 15 63659 iL 6542:3 *6543-4 4 ee a E308 1 3 6363-6 i 6358°1 1 ale Z 63561 13 6533'8 6533-4 3 RObaG “= 6527°7 25 eae 1 6524-9 2\b ca 9 Beet 1 6345°7 1 eu) 1a 6343-0 2 Go16%6 = 6338-0 1 6516:3 6514-4 3 65963 1 6512°6 2 6509°3 2b 6321:0 *6321-4 4 b 65053 2 6318-0 2 6501°7 2. 63142 1 6499-1 13 6313°8 6311°6 4b¥ 6496-4 13 6305°8 a 6493-7 25 6302°3 1 6490-2 13 6300°3 1 6488'1 2 6298-5 1 6485°7 1 62967 1 6482-9 1b 6294-9 62948 3 6480-0 : 6293°2 2 6477°5 13 6290°7 1 6474-1 13 62850 1 6470°8 15 6283-2 2 6465°5 *6467°3 3 6281-0 12 6464-4 2 6278°3 14 6460°3 1 62758 2 64586 6457°5 4 6273°3 = 6452-4 13} pe 6270-9 2 6441°5 1 6268-2 1 * Denotes the chief lines whose wave-lengths were first determined. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 189 NITROGEN— continued Positive Band Spectrum Positive Band Spectrum Intensity Intensity Bn ' and 5 ie and on and Hasselberg Character sas and Hasselberg Character 6249-2 *6251'6 2 6011°8 ¥6012-4 5 6248°3 1 6004°6 6005-1 f 6244-9 1 6000°3 3 6242°6 6242-2 3 5997-6 2 6236°5 13 5995-1 2 6231-4 1 5993-1 1 6229°8 1 5991°7 1 6227°8 1 5990°3 1 6225°5 6225°7 2 ; 5988-7 3 ( 6224-3 2 aN ieee 5986-6 2 6221-6 1 5984-6 1 6219°3 1 5981°5 ul 6217°8 1 5979°9 2 6216-4 if 5977°0 2 6214-4 14 5974°4 1 6211-6 1 5971°5 13 6209°3 1 5969-1 1 6207°3 13 59668 13 6204:°7 1 5963°2 1 6202-4 1i 5960°9 1 6183-2 6184-6 2 5957°3 *5957°9 5 g4 61751 x6174°3 3 5946-0 3 ; 6168-5 1 5943-4 2 6158-2 61572 2 5940°9 2 5939-1 1 6125°4 *¥6126°0 4br 59378 1 6118°8 6118-7 3b 5936-4 1 61141 2 934: 6110°6 1 de 59331 2 h 6107°9 1 59307 1 6102°1 6101-2 2 5928-0 1 6099°1 a 5926-1 2 60829 1Z 5923-4 2 6077°9 1 5920°9 1 60663 ¥6068°3 5 5918-1 2n 6060°6 6060°9 4 5913-4 2n 6058°6 1 5910°1 i 6056-0 3 5907-4 1 6053°2 2 5904-6 *5904°6 5 6050°4 2 5897-5 5897°5 4 6048°3" 1 5893°0 3 6045°5 1 5890°6 2s 6043°3 6043°9 3 5888°3 2 t 6041°9 2 5886°8 u 6040-0 1 5884-7 1 6036-7 1 5883°5 1 6034-9 1 j 5882°0 3 6032-1 1 eet 5880°7 2s 6029-2 1 58782 1 6026°3 2 5875°6 Is 6021-2 2 5873°9 2s 6017-4 1 5870°8 2s 6014-9 1 5868°8 1 * Denotes the chief lines whose wave-lengths were first determined. 190 REPORT—1886. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum oe! pane g fe an ° % an engin and | Hasselberg Character ane and Hasselberg Character 586673 2n 5752-0 *5753'8 © 5 5863°7 1 5745°6 5746-4 4 m 5861°3 2n 5743-0 1 5858-1 2 5742-0 1 5855°5 1 5740°6 1 5853-0 45853-1 : od : 584671 5845-9 4 See 5736°7 1 5841°3 2 5735-0 1 Aiage 2 | | 5730-7 5733°6 1 5838-2 1 See 5 $5731°5 3 5836°6 1L |p mG. = 3 5729°7 1 §835°2 1 s : 5726-2 1 5833-7 1 aot $5724:5 1 5832-4 1 5722-6 1 5830°5 Beata z 5721°3 1 5829°5 3 ’ 5719°9 1 j 58280 1 F n 5718-0 2 5827-0 1 71K. ae 5715°5 1 58257 1 712. ; 5713°6 2 5824-7 1 710: : 5710:0 1 5822-7 2n 5707°9 1 5821-0 1 Lo ‘ 1 5703°8 #57063 3 5819°8 1t 702. : 3 5703°9 1 5818-1 i 5702+! 4 702°3 1 5815-9 Jin mine : 2 57002 1 5813-2 1 : : on 5698-1 1t 5810°8 1jn 5695°5 1 5807-4 1 Rina 2 5805-0 1 a pees) 1} 56903 11 5801°8 *5802-9 5 5687°5 in 5795°3 5795-7 4 5682°5 5684-7 2 5792-2 i 5681°6 1} 5791:3 2 5678°8 1 5789'9 2 5671°8 1 5788-6 1 56579 *5659-2 onbe 5787-1 1 | 9 5652°0 i 5785°8 1 5637°2 56381 1 5784-1 ul ( 5#12°6 ¥5613°8 3 5782-8 tT 5606°3 13 : 5780°9 3 5602°1 aie g 5779-9 Si) ihe 5596-0 0 5778-7 1 ) > #£2 5593-2 1} 5777-5 1 H 5591-0 2 5776-1 1 \ 5586°0 1 57750 1 5567°9 *5569°0 3h $5773-0 1 5567-1 1 5771-4 it 5563-0 5561°8 24 5770°2 1 5560°0 1 57686 it | t 5557-2 1 5766°7 2 i 5555-4 1 5764-1 1 55518 5552-1 3 5761-9 2 : 5549-3 15 5758°5 1 5547-2 LS 5756-4 1 5545-5 13 * Denotes the chief lines whose wave-lengths were first determined. T Double. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 191 NITROGEN—continued. ee eee Positive Band Spectrum Positive Band Spectrum Intensity Angstrém and Thalén 5525°2 5518-7 5513°4 5506'0 5493°7 5482°8 E : 54419 5437:0 5422-1 5406°4 5401°7 Hasselberg 5543°5 5542°0 5535-1 5531°3 5525-4 5523°5 5522-0 5518-1 5515°9 #55143 5509°5 55079 5506°3 5504°6 5502°8 5500°9 5498-8 5496°6 5494-7 5493°6 54916 5483-3 5479°8 *5477°5 5476°2 5472-2 5471-4 5469°3 5464°3 5457-4 54555 5453°1 54513 5448-6 54458 5443-7 *5441-2 54360 5434-1 5432°5 5428°6 5427°9 5426°2 5424-2 5421°7 5419°8 5417-7 5415-9 5413°0 5411°6 5410-1 *5406-2 5403°6 5401:0 and Character Ree ee B. ot fet Fat faa BOD BO He et 2 Fat et bo | bo] to | |bo| Ao] bolPto|H "a et et et DD DD tb be bo eb bo Do} bol ce _bo[t9|9| 29] bel tlh to] Ro|to| CO 0 ee on Ro a! ° Angstrém and Thalén Hasselberg aw( 5487-4 5371-7 5366°7 Y{ 5353-2 5339°7 5306'3 5399°2 5397°5 5393°9 5393-0 5391-4 5389°7 5388-4 5387-1 5385°2 5383°2 5381-7 5380-2 5378°3 53758 5373°T "53716 5366°4 5364°6 5362°9 5359°4 5357-4 5355°7 53543 5352°8 5350°8 5349-4 53477 5346°2 5345°0 5342-9 5340°9 *5338°6 5337-2 5335°5 5333-4 5327-4 5326°7 5324°5 5322°2 5320:0 5316°8 5313-7 5309°4 53069 *5305°8 5303-9 5302:0 5300°2 5298°2 5296-2 5294-1 5287-4 5284-4 * Denotes the chief lines whose wave-lengths were first determined. Intensity and Character bolo | no] bet bt pe et et het Ret et C0 DO to] bo] Ro| wWNmw a Ree et He to[eno|- ion * bo|Pto| no | Bee ee Weak but Sharp Lines 192 REPORT—1886. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity Intensity z and ° E and vad and Hasselbers Character|} An, “aa and Hasselberg Character { 5281°5 5142-4 1 5278-2 5138-7 5137°8 3 5273°'8 *5274:0 3 5134°6 1i "| 5268-4 5126°5 ¥#5126°1 + 5256°3 5256-0 51247 1 5244°6 *5243°1 4 5123°1 2 5239°3 52378 2 5121-2 24 Cc 52345 13 5120°6 22 52322 14 51179 2 5226°5 5225°6 14 51101 14 5213-1 "5212-7 43 5106°7 14 5210°8 1 5100°9 y) 5209°3 1 5097°7 *5098°7 5} 5207°7 5207°8 3 5093°5 1 5205°3 1} 5090°3 1 52040 2k 5083°5 1 5201°8 2 5076°8 2 a 5200-2 Is 5071°8 2 5198-6 Is *5068°3 24 51971 1s 5066°9 +f 3 51961 5195°5 4 5065°6 5065°3 4 5191-2 ae 5063°7 2 5189-7 2:5 5062-4 2 5188°4 eA 5060°9 2 5186°6 28 5059°7 2 5185:2 ae 5058-7 2 5183-4 *5183°5 5 50570 2 5181-7 2 5055°5 3s 5180°5 2 5053'6 3s 5178°9 3 50517 1 6179°3 5177-9 4 5049-5 1 51765 2 504773 1 51748 3 50448 1 5173-0 Is 5042°6 1 5171:6 Is 5040:0 1 ui 51702 1s 5037-1 1 5169-1 Is 5034°3 Ls 5168-0 ls 50320 5030°8 3n. 5165°8 51665 4 *4975°7 QL 5164-7 a 4974-0 3i 5162°5 43 4972:0 4972-2 4h 5161°3 a4 4970-2 2 5159-9 "a oe 4969-1 2 5158°5 eS 4967°8 2 5157-1 za) 4966°5 2 5155-9 2! 4965°2 2 5153°7 #51545 5 4963'8 b 5153°1 13 4960'8 51516 24 4959°5 24 »} 5149°0 5149-4 3 ; 4957°5 3 f 5148-4 34 4955°3 gu 5147-1 1 49534 24 51458 3 4950°9 2 5144-1 1g 4947°'8 2 * Groups a to & by eye-observation, Groups a too recorded by photography. + Strong triplets. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 193 NITROGEN—continued. a EE ene Dn et ee I ee ee Positive Band Spectrum Positive Band Spectrum Intensity Intensity d a t and a an ae and Hasselberg Character ay aay and Hasselberg Character 4945-6 2 4811:7 4812-0 J 6 4943-8 12 4811-2 3 4940°8 14 4810-4 4810°4 3 4937-7 ie 4809°3 4809°4 32 4934-5 ui 4808-2 4808°5 3k 4931-1 1 4807'2 4807°4 3h 4919-0 4917-5 3 4806-4 pa 4916744] 4 4805'8 24 *4915°7 5 4805'1 28 4914-7 2 4804-2 23 4913'8 2 4803-7 4803°8 24 4913-0 2 4802-4 4802°6 4 49119 2 4800°7 4800°8 4 4910-7 2 4899-2 4799-2 3 4909°8 2 4798-4 a1 4909'1 2 4897°3 4797-2 22 4908'3 2 47962 2 4907-2 3 4895°3 47953 2h 4905-7 3 4794-9 24 4903-9 3 4893'6 4793-4 22 4902-0 1 4792-7 2 4900-2 2 4891-1 4791°3 3 4898-6 2 4790°1 3 4897°6 2 4888°7 4788°8 3 4896°2 2 4787°8 2 4895-0 2 4886'1 4786-2 3 4893-8 2 4785-0 2 4892°6 2 7 4783°8 2 4891:3 3 4783:3 2 4 4889-9 13 47823 2 4888-5 3 4781°1 2 4887-1 4780°3 2 4885:9 47793 2 48851 4778°3 1 4884°1 a 4777-2 1} 4882-7 A 4776-2 1 4882-0 4 4772°8 1 4881-0 4 4771-9 13 4880-0 = 47707 13 4878°8 4769-7 re 4877-7 4768-7 15 4876-7 4767-4) 13 4875-4 fe 47663 11 4874°3 iz 4765-4 12 4873°5 13 47637 12 4872-0 1 47628 re 4870-9 1 4759-9 1 4869-8 1 4759-0 12 4868-1 2 4758-2 2 4866-6 1 4756°3 2 4865:1 1 4755°4 12 4814-0 *4814-0) 4 arses | 1 48130" 48i30ft | 5 4752-3 | | 4751-3) | * ise. a to k by eye-observation. Groups a to o recoried by photography. t Strong triplets, ; i) Fy 194 REPORT—1886. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity Intensity 2 and 4 and se a and Hasselberg Character See and Hasselberg Character 4750°5 J 4682°7 47482 4681-7 ATAT-4 4680°6 47464 4679°6 a 4743°9 g 4678°5 # ATAZ‘1 a 4677°5 4 4742°3 = 4676°6 “4 ly, ys 27397 H 4675°2 3 a 4738 at = 46743 = 4738°1 o 46732 4735°5 = 4671-7 47347 BP 4670°9 4733°8 Rs 4669°9 4730°8 4668°1 4729°8 4667°3 4728-9 | 4665°8 2 4725°9 46660 46652 3 4722-7 #47227 4 *4664-4 4 4722-0. B 4663°8 2 47215 a7are t+} 5 4663°1 3 4720°2 4720-4 6 4662-4 2 4719-4 3 4661°6 2 4718-4 4718-4 32 4660°8 2 4717-2 4717°3 34 4659°8 2 47160 4716°3 34 4659°3 G 4715°1 32 46587 14 4714-1 2 4658-0 2 4713°4 2 4657°4 1 4712°8 2 46566 3 47117 3br 4656-0 1 4709°9 4710-0 4 4655°1 23 47092 1 4653-8 2 4708-2 4708°3 4 4653-0 13 47063 4706°6 3 4652-2 2 4706°1 1} 46511 2 B\ 4704°5 4704-7 3 4650°6 2 4703°8 2 4650°0 2 47030 2 4649-0) *4648°6 4 4702°7 4702°5 2 4648°6 f t 4701°5 2 4647-2 4647°3 5 4700°9 4700°9 2 4645-7 4645-9 6 4700-2 2 4644-8 4644-7 3 4698'8 4698-9 3 4644-0 4644-1 3ibr 4697°8 14 4642-8 4642-9 4 46962 46964 3 4641-8 4641°8 3 4695°5 14 || x 4640-7 4640°8 4 4693-7 *4693°'6 3 4639-6 4639°7 4 4692°5 1 4638:2 4638-4 4 4691-0 4690°9 ar 4637°3 23 4689°6 g: 4636°6 34 4688°4 a 4636:0 24 4685°6 a3 4635:0 3k 46848 ea 4634-5 ot 4683-8 46329 4633°1 4 * Groups a to k by eye-observation. Groups a too recorded by photography. +t Double. { Strong triplets. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 195 NITROGEN—continued. Positive Band Spectrum ie} Angstrém and Thalén 4631°3 4629°6 4627°5 4621°5 4619-2 4616:7 4614:0 4611-4 4608°7 4574-0 Hasselberg 4631-4 4630°9 4629°7 4628-8 4627°7 4626-7 4625'8 4625-2 4624-3 4623-7 4623'1 4622°5 4621:9 4620-7 *4619-2 4618-0 4616-7 4615-5 4614-1 46128 4611°5 4611-1 4610-0 4608'8 4608:2 4607°3 46061 4605+ 4604°2 * 4603-0 4602:2 4601-1 4600-0 $*4599-0 4597°8 4596-7 4596-0 4595-3 4594-4 4593-6 4592-3 4591:2 4590-2 *4573-5 4572'8 4572-0 4570°7 4570'1 4569-2 45683 4567°5 4566°6 4566-0 4565:4 hs Intensity and A Character|| Angstrém and bole bole TS) wl bo|*Ro|bo| 20 | De RNDE DEF DOWN NEN WRN RF NN WN WHR Reb wb whe wo] 2o|/20 | Weak Lines DWNwhwwWWWWWN OP bo] to] to) Hasselberg Positive Band Spectrum Intensity and Character 4564:°5 4563°1 4561°7 4560°3 4559°4 $4558°6 4557°5 4557-0 455674 45555 45545 45533 4552°3 *4551°1 4550°0 45488 4547°6 4546'7 4546:0 b\|- bole Ro|e Ro] i or rss or tbo RD = et = 2D = DD DD DS SW DS WH DO DD DS le ah bole b|- bole Lo) Ld ~~ nr - ns Oo DO bet bet DD * Groups a to & by eye-observation. Groups a toorecorded by photography. + Double. + Strong triplets, 02 196 REPORT—1886. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum meee ik Intensity an d Angstrém and Character Angstrém and Ohiradtes halen Hasselberg Thalén Hasselberg | / 4507-2 Zn 4442-7} | 4506-6 1 4440-9 4504-0 Lin ss402 | tors | ate 44376 gn 437° 4489-0 4489-4) 4. 4437-0 aass6 bt] 6 4436-4 4487-7 | 6 4434-3 4486°8 3 ‘io . 1 ° | qso2 | af || 41308 / 4484-3 3h 4430-1 4483-5 3h 4429-6 4482°6 Qi 4427-2 | 4482-3 at 4426-7 4481-6 ot 4426-0 4480-8 3b 4423-6 44794 4y 4423-0 4478-0 4br 4422-4 4476-6 3 4417-0 44159 4 ae: | 4474-1 a4 4413-4 Qh 4473°4 ak 44128 3 cama | | a aud . [ae 4471-7 2 44103 2 4471-0 25 4410°0 ot 4469-9 gi 4409'3 rae ¢ 4469-0 2 4408'8 a {1868 2 4407-5 a 465° 4407-0 2 ae ee 4463-5 1k 4404-7 4 4462:5 iy - 4403-3 4 4461-6 14 4401-9 3h 4460:9 if 4401-4 2 4460/1 1 44004 3 4458-4 1: 4399'5 2 4457-5 1 4398-8 2 4454-9 1 4398-5 2 4454-1 Ly 4397-7 2 4452-9 1 4397-1 2 4452-2 F 4396-5 2 ae | =e 4449-3 i 4394-5 2 ire ae ee as if 4 . 4446: if 4391-2 oh *4444-9 4390-2 4443-4 *4389°3 2 * Groups a to k by eye-observation. Groups a to o recorded by photography. Strong triplets. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 197. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity Intensity ° and 5 and een and Hasselberg Character a and Hasselberg Character} 4388-1 1:2 4338'8 4 4387-0 4337°9 22 4385°7 43373 3 4384-7 4336-7 2 4384-1 433671 ca 43832 4335-4 1 43823 4334°8 4 4381-4 4333°7 4 4380°7 4333:0 13 4379°8 4332-4 2 4378°8 |. 43315 3 4378-0 | 4331-0 ai 4377-1 4330°4 4376-1 4329-7 33 4375°2 4329-0 1 43744 4328:0 3 eal | 4327°3 2 4372-4 4326-1 3 4371-7 | 4325°3 2 4370-2 43243 23 4369°5 4323-4 ii 4368°7 4322-4 2 4367:9 4322-1 1 4367-1 4321°4 ii 4366-4 4320°6 2 n 4365-6 4319-9 13 4364-0 4319°2 2 4363-4 ¢ 4318-4 2 4362°6 43176 ly ¥4356°9 4 43169 ly 4355°8 5 43162 i 4355°0 2 43153 1 4354-5 6 *4314-6 14 4353-4 3 43139 13 4352°8 4 43129 43518 4 4312:2 4350°9 4 43115 4349°9 33 4310°3 4349-2 2 4307°7 4348-9 3 4301°1 43479 4 4307-7 4346°8 2 4307°1 4346-4 23 4306°5 4345°8 2 43051 43451 2 4304°4 4344-4 4 4303°8 2 4343-8 4302/1 2 4346°0 *4343°2 6b 4301°6 = 4342-6 4301-0 a 43422) 21, 42992 4 4341-6 f ap 4298°6 3 4341-0 12 4298-2 e 4340°3 4 4296°3 4339-6 4 4295-7 * Groups @ to k by eye-observation, Groups a to o recorded by photography. 198 REPORT—1 886. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity , rr i, an an Angstrom and Hasselberg Character Angstrom and Hasselberg Character 4295°2 42369 ¢ 4293-2 wo} 4292-6 4235°5 4292-1 4234-4 42710 *4269-4 4 4233°8 42688 6+ 5 4233-1 42680 6 4231-7 4267-4 2 4231-1 4266°8 4 4230°5 4266°2 4 4229°1 4265°5 33 4228°5 2 4264-6 3 4227-9 2 4264-1 3 4226°3 a= 4263°7 2 4225°8 a 4263-1 3 4225°1 4 4262-7 2 4223-4 ir 2: : seo | ty | oo 4261-5 4 4220°5 42609 2 4219-9 4260°3 4 4219-4 4259-7 1 4217-5 4259°1 33 4216°9 4258°8 2 42163 4257°9 34 4214-2 4257-2 2 4213°7 4256°6 3 421 sa 4256°2 2 4211-0 a4 4255°5 24 4210°5 S ' 4255-1 ot 42100 E 4254-6 ai 4208-3 b wo37 | 3k foray | 4253-0 2k 4203°3 *4251-9 35 42030 "4201-0 4 4251-2 2 soo 5 4250°2 BT 4199-6 6 4249°3 25 4199-0 3 74248°3 2 4198°5 4 4247-4 2 4197°8 4 4246°6 23 4197-2 34" 4246-1 2 4196-4 35 4245-4 23 4195-7 3n 4244°5 24 : 4195°5 3n 4243-9 2 41949 3 4243-4 } lb 4194-5 3 4243:0 4194-0 24 4242-4 2 4193-4 3 4241°6 2 4193-0 4 4241°0 2 4192-2 4 4240-2 [ 2 4191-7 res 4239-4 2 4190-9 4 4238-7 2 4189-7 3 *4237-9 2 4189°3 2 * Groups a to k by eye-observation. Groupsatoorecorded by photography. + Double. ¢t Strong triplets. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 199 NITROGEN—continued. Nee ee Positive Band Spectrum Positive Band Spectrum Intensity Intensity ° and er: and An a and Hasselberg Character san and Hasselberg Character 4188-4 3n || ( 41440 "4141-1 ) 4 4187-7 Q1 41402¢] 6 4187-0 3 4139°5 J 6 4186°8 3 4138-7 cae 4186-2 QL 4138-3 3h 4185°7 3 4137°8 2 4185°1 3 4137-4 32 4184-3 QL 4136-7 3h 4184-1 21 4136-1 2h 4183-4 3 4135°6 ok *4182°7 32 41351 |1 9, 4181°9 21 41347 =| ff 4180°9 31 4134-0 3b 4180-0 2 4133-7 } 417971 21 4133-1 2 4178-1 2 4132'6 3 4177-2 2 4132-2 22 4176°7 2 *4131°3 4 4176-0 22 4130°7 1 4¥75°2 1 413071 4 4174-6 12 4128-8 33 4173°6 1 4128-4 21 4171°8 1 4127°5 3i #4170°8 Qu 4126-9 ot 4170-0 2 4126:3 2 nica 2 4125°9 4 , 4168-6 2 - 4125-3 Qh 4167-6 2 4124°8 2 4166-9 2 4124-3 28 41662 2 4123-6 2 41651 12 4123-2 23 net! 11 4129-7 2 4162-6 11 4121-7 22 sio19 a 4120-9 11 4161-2 11 *4120-1 3 4159-9 es 41183 2 4159°3 14 4117°3 12 4158-7 11 4116-4 1 4157-2 11 4115:2 <1 4156-6 11 4114°5 <1 4156°1 11 4114-0 <1 4154°3 1 4113-3 12 4153'8 1 suas b 12 4153-2 1 4111-9 1i 4151-5 1 411-1 1 4151-0 1 4110°3 12 4150-4 1 41096 13 4148°5 41089 re 4147-9 nd 4108-2 1 4147-4 Ss 4107°3 4145-5 4106-6 4145-0 E L066 4144-4 > 4104-9) 4104-2 | * Groups ato k by eye-observation, Groups ato orecorded by photography. + Double. + Strong triplets 200 REPORT—1886. NITROGEN—continued. a ST SE Se | Positive Band Spectrum Positive Band Spectrum Bice Intensity an 5) and An peom and Hasselberg Character Ange and Hasselberg Character 4103°6 J 4064-9 4102-4 4064-1 siors b 40637 4101-1 4062-7 4099°9 40620 4099°3 4061:1 4098°6 4060°6 40972 4059'8 4096-7 } 4063:0 *4058°7 43 40960 40583 5 4098:0 "4094-2 4 ; 10583} 6 4093°7 2 4057°3 4 4093:2 5 4056°8 4 4092:1 6 40563 4 4091°6 24 40558 34 40910 25 4055°5 3 4090°5 23 4055°2 3 4090:2 2 4054-7 33 4089°6 3n 4054°3 3 4088:9 3 4053°9 33 4088:3 2ibr 4053°5 3 4087:3 24 4053:1 3 4086-9 ot 4052°7 3h 4086'1 3 4052°2 1in 4086:0 3 40520 lyn 40852 22 4051°5 4in 4084-9 24 4051/1 1 4084:3 2 4050°9 1br 4083'6 3 4050°5 4b* 4083:3 2 4049°4 - 40823 4 40489 3 4081:0 4 y 4048-3 3 ; sora | 1 sour] 8 *4078:3 3h 4047-2 3 4077-7 1k 4046°8 3 4077-0 2 4046-2 22 4076:8 2 4045°8 3 4076-1 2 4045-4 3. . 4076'5 2 4045:0 l 4075:1 2 4044°6 35 4074-4 2 40439 25 4074-0 2 *4043°2 4s 4073-4 2 40426 22 4072°6 2 4041-7 3n 4072-4 2 4040'9 3 4071-7 2 4040-2 gi 4070'8 2} 4039°8 25 4069°9 1 4039°2 25 4068-9 25 4038°5 25 4068-0 In 4038-0 aa 4067-0 14 4037°4 25 4066:0 4036:7 25 4065-2 4036-1 ak * Groups a to & by eye-observation, Groups @ to o recorded by photography. { Strong triplets. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 201 NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity Intensity ° and a and se akipan and Hasselberg Character see and Hasselberg Character 4035°5 gu 3993-7 QL 4034:9 = 3993-5 ot 4034-2 a 3993-0 2 4033-6 = 3992-7 B: 4033-0 J Qt 3992°3 3 4032-2 2t 3991-9 3 4031-6 ' = 3991°5 24 4031+ on 3991°3 of 4030-0 2 3990°8 3h 4029-5 \ 2 3990-4 1 4029-0 2 3989-8 4 *4027-8° 2 3989-4 1 4027-3 t 2 3989°1 1 4026°8 | 2 3988°7 4 4025°6 2 3988°5 2 4025-1 2 3987°7 33 4024-6 2 3987'1 2k 4023-2) 14 3986°6 3 4022°8 \ 14 3986°3 3 4022-3 f 1 8985°8 3 4020°8 it 3985-4 3 q sso it 3985°0 3 4019-9 13 3984°3 24 4018-4 1 3984'1 25 sorral 1 3983°6 25 40175 1 3982-8 3 4015°8 1 3982'1 24 4015-4 \ 1 % *3981-2 ai 4015-0 1 3980°5 - Ok 4013-2 \ 3979°7 3 4012-7 Me 3979°5 3 4012-4 J = 3978-9 25 4010°5 a, 39781 2 go101 | Bi 39778 25 4009-7 = 3977-2 pa 4007-7 ‘a 3976°5 2 4007°3 2 39760 2 4006-9 a 3975°5 1 4004-9] 2 3975°3 13 4004:5 8 39748 2k 4004-1 f 2 3974-1 2 4001-9 % 3973'5 2 . soors | A 39729 2 4001-1 3972°2 2 4002-0 *3997-8 4 3971°6 2 sural 5 3971-1 2 3996-6 6 3970-2 2 3996-4 4 3969°6 2 a 3995-9 3 3969-0 2 3995-4 4 39681 L 3994-9 3 3967-6 it 3994-7 2 3967-0 it 3994:3 3 3965°9 2 3993-9 2h 3965-4 ie * Groups a to & by eye-observation. Groups a to o recorded by photography. + Strong triplets. © 202 REPORT—188v. NITROGEN—continued. Positive Band Spectrum Positive Band Spectrum Intensity nee a and » an a ae oy and Hasselberg Character eee and Hasselberg Character 3964-9 j Ii 3956°6 3963°8 13 3956°1 39632 1z 3955°7 2 3962°7 13 3954:1 aa 4 3961°4 1 o sass | a 3960-9 1 3953-2 bet 3960-4 J 1 3951°5 Pa 3959-1 1 3951-1 > 3958°6 1 3950°7 3958°1 1 NitroGen—continued. Negative Band Spectrum | Negative Band Spectrum Intensity Intensity Q 4 and tl og } and eae and Hasselberg Gan ae and Hasselberg Character 4709°3 *4708°6 5 4633°3 1 4706°8 1 | 4632-7 23 4704°6 1 / 4631-1 1 4702°8 1 | 4629-9 3 4701-0 2 4629-0 1 4699°9 1 4627-2 13 4698-7 23 | B 4625-1 1 4697-2 1 | 4624-6 1 4695'9 3 | 4620°8 24 4694-4 1 4616-1 14 te 4692°8 3 4609°0 1s 46911 1 4606°5 14 4689°4 3 46009 1 4687°5 1 4685°6 25 4601-2 *4599°4 5 4683°6 if 4597-7 2 4681°5 2 4596°5 2 4679°3 1 45943 14 4677°2 13 4593-2 1 4674-7 1 4592-2 2 4672°3 F 4591°2 1 4667°3 1 459071 22 4653°6 *4651°2 5 4588'8 15 4649°2 2 Cc 45874 | 3 4644°8 1 45861 13 4643°8 2 4584-7 3 4642°6 iE 45831 13 B 4641°5 25 4581°5 3 4640°2 iz 4579°8 13 4638°8 24 4578:1 24 4637-4 1z 4576-1 1 4635°9 2k 4574°3 1 46343 1g 4570°2 2 * Groups a to k by eye-observation. Groups a to o recorded by photography. ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS. 203 NITROGEN— continued. Negative Band Spectrum Negative Band Spectrum Intensity Intensity ° and a and oe and Hasselberg Character ae and Hasselberg Character 4555°2 4553°8 5 4271-2 33 *4552°9 5 42702 25 4549-0 14 4269'2 4 4548-0 1 42680 24 4547-0 2 42669 4 4546-0 1 4265'7 22 4545-0 2br 4264°5 4 4543-8 1 4263°1 3 4542°9 2 4261-7 4 4542-0 2 4260°3 2k 4540°9 2 4258'8 4 D 4539°5 i 2 4257°2 2h 4538-0 1 42555 33 4536-4 2 42539 2 4535°3 1 4252:2 3 4534-0 1 4250°3 2 4533°3 1 4248°5 22 4532°5 14 4246°5 12 4529°8 1z 4244°6 2 4529-1 1 4242-6 1 4525°7 1 4240-4 1 4525-4 1 4236°5 1 4521-4 1 4516°5 *4515°3 5 4239°0 *4236°3 5 45143 13 4235°1 33 4513-4 13 4234:3 3 4512-7 14 4233-9 2 4512°2 12 4233°3 22 45101 13 4232-8 i 4509°2 1 42313 2 4508'3 2 4230-4 14 4507°3 1 4229°5 3 . 45062 2h 4228-6 2 450571 1 4227°6 3h 4503°9 3 4226-6 az 4502°6 1 4225°5 4 4501°3 3 4224-4 24 4499°9 1 4223-1 4 4498°5 Ee 4221-9 22 4496°9 1 4220°5 34 4495°3 2 4219-4 1 4493°6 1 4219-1 1 4491-9 2 4218-4 13 s { 4484-9 4 4217-6 2 4484°3 4 421671 2 4281:0 *4278°0 5 4215-4 1 42769 3 4214°5 2 4276°5 3 4214-1 2 42761 3 4212-7 2 G 4275°6 23 4211-1 2 4275-0 3 4209°3 1 4274-4 2 4207°6 i 4272°9 22 4203-6 1 4272-1 2 * Groups a to k by eye-observation. Groups a to o recorded by photography. 204 REPORT—1886. NITROGEN— continued. Negative Band Spectrum Negative Band Spectrum Intensity Intensity 5 and a and An = ea and Hasselberg Character eo and Hasselberg Character ‘4203-0 *4198-7 5 4187°3 i 4198°3 4 41861 3 4197-7 34 4185°0 14 4196°9 34 41836 3 4196°4 2 4182°3 13 41959 2 i 4180°9 23 : 4195'3 2 4179°4 1 4193-9 13 41779 2 4193°3 2 4176-4 13 4192°3 2 4174-7 1 41914 13 4172°9 <1 4190°6 24 4171:3 1 4189'6 1 x { 41750 *4166°3 3 4188-4 3 *4165°6 3 Second Report of the Committee, consisting of Professor TILDEN, Professor W. Ramsay, and Dr. W. W. J. Nico (Secretary), ap- pointed for the purpose of investigating the subject of Vapour Pressures and Refractive Indices of Salt Solutions. ia Vapour Pressures of Salt Solutions. Four salts, NaCl, KCl, NaNO,, and KNO,, have been completely examined, in solutions varying in strength from one molecule of salt per 100 water- molecules up to solutions nearly saturated at the temperature of experi- ment. The method employed was similar to that described in the previous Report of the Committee, with this difference, that in this case the solu- tions were kept of constant strength and the temperature was the variable. As before, the pressures at definite temperatures were deter- mined, and not the converse. The experiments, though covering the same ground, are completely distinct from those described in the previous Report, and are not only more complete, but more reliable, being means of four independent observations, and it is believed as free from the effect of superheating as it is possible to obtain them by this method. The zinc introduced to prevent succussive boiling has been proved to have no influence on the results. The solutions were of the following strengths :— NaCl 2, 4, 5, 6, 8, 10 molecules KCl 2, 4, 68,10 ,, NaNO, 2, 4,5, 6, 8, 10, 15, 20, 25 molecules KNO; 1, 2, 3, 4, 5, 10, 15, 20, 55 a all in 100 H,O, and the temperatures were 70°, 75°, 80°, 85°, 90°, 95°. ON VAPOUR PRESSURES AND REFRACTIVE INDICES OF SALT SOLUTIONS. 205 The results confirm in all respects those obtained in the previous pre- liminary experiments. They are as follows :— (a) When temperature is constant and concentration (m) varying, —! s ; ‘ then 2 — increases rapidly with NaCl, more slowly with KCl; diminishes slowly with NaNO;, and very rapidly with KNO,, the order being NaCl, KCl, NaNO., KNO,;. The figures show a clear agreement with those of Tammann (Wiedemann ‘ Ann.’ xxiv), obtained by the barometric method. This is entirely at variance with Wiillner’s statement (Pogg. ie ‘Ann.’ cx.) that 2—P is constant for all salts; a statement not borne out by his figures, discordant as they are. (8) When x is constant and temperature varying, then the value of — 1 * . PT? ic. the restraining eftect of each salt molecule, is a diminishing n Baattity in the case of NaCl, practically constant with KCl, slowly in- creasing with NaNO, and rapidly increasing with KNO,, the order being the same but reversed. This also is confirmed by Tammann, and agrees with the results of Legrand (‘ Ann. Chim. et Phys.’ 1835). (vy) When, too, the temperature and concentration increase, the salts form the same series: decrease of restraining effect with NaCl, less so with KCl, no change with NaNO;, and a marked increase with KNO3. Connected with the above are :— (6) The order is the same when the solubility as a function of the temperature is considered. NaCl has its solubility only slightly affected by rise of temperature, KCl more so, NaNO still more, and KNO; greatly so. ; (e) The value of P —# , where n=1, is very nearly the same for all four salts at the same temperatures. (2) The heat of solution for— NaCl =—1:180| KCl =—4400 NaNO,=—5:200 | KNO;=—8°500 Again the same series. The behaviour of these four salts can be satisfactorily explained on the lines of the theory of solution laid down in a paper on the nature of solution (‘Phil. Mag.’ 1883); but for the details reference must be made to the memoir. II. Refractive Indices of Salt Solutions. The work of nearly all previous experimenters on this branch of the subject of solution is unavailable for any systematic examination of the point, inasmuch as but few salts have been examined, and only a few solutions of each; while even in these cases the results require re- calculation, as the solutions examined were of percentage composition, and the conversion of these into terms of even molecules of salt per 100 ’ H,O is a laborious process, requiring a large amount of interpolation, for which the data are generally insufficient. Recently, however, a paper by Ostwald has come into our hands (‘ Volum. u. Optisch-Chem. Studien,’ Dorpat, 1878), which contains the necessary data for a partial examination of the subject. Ostwald’s ex- 206 . REPORT—1886. periments were conducted with solutions containing one equivalent in grammes of the base or acid in one litre of the solution. Consequently the.salt solutions obtained on neutralisation contain one equivalent in grammes of the salt in the two litres. These solutions, though not strictly comparable, are still nearly so, and are of the approximate strength, MR. 110H,0. The results obtained by Ostwald are as follows :— (a) When a solution of a base (potash or soda) is neutralised by the requisite amount of the solution of an acid (fourteen organic and inorganic acids), the difference between the sum of the refractive indices of the two solutions before mixing and twice the refractive index of the result- ing salt solution is a value almost identical for both bases, no matter what may be the acid. There is thus complete parallelism between the change of refractive index and of molecular volume on neutralisation. (6) The conclusion is that the alteration in the physical constants, brought about by combination, has a constant value for each constituent which enters into the combination, and is therefore independent of the other constituents with which the first may combine. Thus there is little room for doubt that in other cases also alteration in molecular volume will be accompanied by parallel changes in the refrac- tion equivalent. Unfortunately, Ostwald’s results are not of a form to permit their conversion into refraction equivalents, or it would be pos- sible to show, even more clearly, the close connection between these physical constants. III. Saturation of Salt Solutions. Tt has long been known that a salt is able to drive another out of solution in very many cases, partially or completely, while in other cases the solubility of one or both salts is largely increased. When the two salts are capable of forming well-defined double salts, then either salt added to a saturated solution of the other completely expels it from solution. On the other hand, when the two salts are iso- morphous, and are thus able to form mized crystals, then the expulsion from solution is only partial (Rudorff. Wiedem. ‘ Annalen,’ xxv. 626). This may be explained as follows :— Double salts do not exist as such in solution; the saturated solution of a double salt is therefore not necessarily saturated for either of its constituents, but may be able to dissolve more of one or other of the single salts. As the amount, however, of this salt increases there arrives a point at which the solution has become so rich in this salt (B) that any one molecule of the other salt (A) may be regarded as being in contact with a molecule of B; aggregation or combination to form the double salt (AB) is then possible, and crystallisation proceeds pari passu with the solution of B, and results finally in the complete expulsion of A from the solution in cases where the attraction between A and B exceeds the cohesion of either A or B. While, on the other hand, if this is not the case the expulsion is only partial. This explanation is strongly supported by the stability and definite character of the well-defined double salts, which are totally expelled from solution, and by the insta- bility of those salts which are only partially expelled, and also by the 1 Published Phil. Mag. January 1886. ON VAPOUR PRESSURES AND REFRACTIVE INDICES OF SALT SOLUTIONS. 207 fact that the saturated solutions of pairs of salts which do not crystallise together are unaffected by excess of either salt. IV. Expansion of Salt Solutions. The results described in the previous Report have been completely examined, and will soon be published. The following may be added to the conclusions already arrived at :— The effect of heat on the volume of a solution of a salt depends on the solubility of the salt as a function of the temperature. If the solu- bility be little affected by temperature then the volume curve approaches more nearly to a straight line than when the solubility is largely de- pendent on temperature. In the former case the effect of heat is simpler than in the latter. In the one the solution is practically of the same strength throughout. In the other the rise of temperature is attended not only by expansion, but also by what is practically dilution of the solution. Thus it is at present impossible to trace out a further connection between solubility and rate of expansion of a salt in solution. V. Water of Crystallisation. An examination of the evidence derivable from the results of thermo- chemical investigations, and also a comparison of the molecular volumes of dissolved salts, lead to the conclusion that no part of the water in a solution of a hydrated salt can be said to be in a different relation to the salt from that of the remainder of the water. In other words, water of crystallisation cannot be recognised in solution either by thermal or volume changes—it is indistinguishable from the rest of the water. The argument based on colour changes of solutions of CoCl,, &c., does not affect the above, for it is not contended that the salt is anhydrous in the game sense as it is when dried at 150° C. Second Report of the Committee, consisting of Professors Ramsay, Titpen, MarsHatL, and W. L. Goopwin (Secretary), appointed for the purpose of investigating certain Physical Constants of Solution, especially the Expansion of Saline Solutions. GRAHAM, in a series of interesting experiments, has shown that saline solutions absorb water-vapour from a saturated atmosphere (‘ Edin. Journ. of Science,’ xvi. 1828, pp. 326-335; also Schweigger, ‘ Journ.’ lili. 1828, pp. 249-264). This process he called invaporation. His experiments were made by enclosing, in a tin canister containing water, glass basins in which were equal weights of (generally) saturated solutions. After a few days the canister was opened, the dishes weighed, and the gain of water by invaporation thus determined. The relative rates of invaporation thus became approximately known. But these rates estimated in this way are influenced by the rate of diffusion of water-vapour in air, and by the rates of diffusion of the salts in water. The latter especially must be taken into account in interpreting Graham’s results. A salt with strong 208 REPORT—1886. attraction for water, but low rate of diffusion, might show less invapora- tion than one with a weaker attraction for water but a higher rate of diffusion. Thus, potassic chloride diffuses faster than sodic chloride, but the latter has the greater attraction for water vapour. If solutions of these two salts were confined in a space containing water, the sodic chlo- ride solution would at first attract water more rapidly, but the consequent dilution of the surface layer would not be counterbalanced by diffusion so rapidly as in the case of potassic chloride; so that the rates of invapora- tion might become equal, or that of potassic chloride even greater. Some experiments made by us have given indications of these phenomena. If the rates of invaporation, not complicated by diffusion, could be accurately measured, a comparison of such measurements would be valuable, by giving indications of the formation of hydrates in solution. They would also be of value in considering the ‘ Correlation of Physical Properties of Solution with Concentration,’ in the manner indicated by D. Mendeléeff (‘ Ber. Deut. Ch. Ges.’ xix. 370-389). But the subject can be investigated in a different way and with promise of more fruitful results. When two salts are enclosed in the same space with a certain quantity of water, the salts tend to keep the atmosphere dry by con- densing the water-vapour. This goes on until all the water is evaporated except that small portion which remains in the condition of vapour. The question at once presents itself, in what proportion will the two salts divide the water between them? The proportion will be influenced, probably, by the relative masses of the salts and the water, and by the temperature, as well as by the relative attractions of the salts for water. If the salts are in molecular proportion, they might be expected to divide the water between them much in the same way as equivalents of caustic soda and potash with a simple equivalent of sulphuric acid in solution, That is, if the attraction of salts for the water which dissolves them is of the same nature as that between acids and bases, the partition would be in proportions representing the relative attractions of the salts for water. It was to test the correctness of this reasoning that the following experi- ments were made. The salts were carefully dried, and weighed out in small test-tubes (55 cm. long and 1 cm. diam.). The quantities used were in the ratio of the molecular weights. Thus, in the first experiment (I.) the masses of the salts were two-hundredths of the gram-molecules, and the quantity of water eight-hundredths of the gram-molecule. As a rule, the water was divided between the two salts, because by so doing we thought to hasten the completion of the experiment. Experience, however, has decided us to abandon this method in favour of enclosing the water along with the salts, the three in separate small tubes, so that the process of invaporation may be watched from the beginning. The salts and water were sealed in a large glass tube (about 10 cm. long and 4 cm. in diameter) before the blowpipe. When the small tube containing the water appeared to be dry, the enclosing tube was opened, the small tubes with their contents weighed, and then resealed. Invaporation was very slow, owing to the small surface exposed by the liquids in the narrow tubes. Shallow vessels would have been better, but the hermetical enclosing of these pre- sented such difficulties that the narrow tubes were used in preference. Heating to 100° C. and cooling gradually was also tried as a means to hasten invaporation. This was found to have the desired effect up to a certain point, beyond which the water began to condense on the enclosing EXPANSION OF SALINE SOLUTIONS. 209 tube. The results of the experiments are here put in tabular form. In the first column the formule of the substances in the small test-tubes are given; in the second, the masses of the substances in grams ; in the third the number of days between the first sealing and the first opening of the enclosing tube; in the fourth, the quantities of water adhering to the salts at the time of first opening; and following are pairs of columns iving similar data for the second, third, and fourth times of opening. The quantities of salts and of water are also given in molecules, 100 molecules of water being taken as the basis of calculation. in each case is the time elapsed from the beginning of the experiment. in [S28] waterin [SE8| waterin [SEE] wt Massin ||P a aterin ||SES& ater in 3 ater in Substances grams z ec grams £ ss grams = ss grams oFs 25s 25s | Jz A= NaCl 1:1672 56 0°8058 159 1:1978 172 1:2392 KCl 1:4882 — 0°6292 — 0:2332 — 0-1900 H,0 . 1:44 _— 1:4350 — 1:4310 —_— 14292 Number of Water in Water in Water in molecules molecules molecules molecules NaCl. ’ 25 — 55°96 — 83:18 — 86°06 KCl . , 25 — 43°69 — 16°19 — 13:19 HO . . 100 — * 99°65 a 99°37 — 99°25 EXpEriMent II. a a = =] 2 So a Ho no) se Oo S q Sa a Of a & O's a pies On an a a |e Ieee] se ese] sa eee] 38 WSEe be | 26 |e22] 26 |2e2] 26 [ees] 22 [22] £2 ort A=, =| S.5 a pig omen | eee ae ee (oe ia Oc NaCl | 0°5836 111 09516 155 | 11160 276 | 1:3331 290 | 1:3386 KCl. | 0°7441 — 0:4866 — 0°3166 — 0:0991 — 0:0976 H,O. | 1:44 — 1:4382 — 14326 — 1-4322 — 1°4362 c3 #2 #g £8 re gey ael ae: | ger | | Eg Be are = g NaCl | 12°5 — 66:08 — 77°50 — 92°58 —_— 92°96 KCl.| 12°5 = 33°79 — 21:99 — 6°88 — 6:78 H,O.} 100 _— 99-87 — 99°49 — 99°46 — 99°74 EXPERIMENT I. The ‘ period’ 210 REPORT—1886. Experiment III. =] Ss r=] =| 3 ee Sig ee Sop Bl Sip Ss | ome ies 2 | 2 |EEs| £2 |Es2| 22 [ES] $2 |EES] 38 3 sea] Sh |loeg|] Sh Issa] Sh 1SSq] S & eae Sia ae meh fie aa c= NaCl | 0:1459 111 | 0:6788 0:7020 249 | 0°7493 262 | 0:7539 KCl. | 0:1860 — | 07710 0°7370 — | 06831 — | 0°6785 HO. | 1:44 —_— 1:4498 — 1:4390 _ 1:4324 _ 1:4324 SB 8 £3 AS #8 53 e} | = 3 Blois la jee a= BE Ee Ee BE NaCl | 3125 -—— AT‘ 14 — 48°75 — 52:03 — 52°35 KCl. | 3:125 _ 53°54 — 51:18 — 47-44 — 47:12 H,O.| 100 — 100°68 — 99°93 iil 99°47 == 99:47 EXPERIMENT IV. 3S) 68 8 Sabstannts Mass in eB ae Water in s g 5 Water in rs z cy Water in grams Bae grams gee grams Ba grams Ay bos Fa Se Oy po a 42) ae NaCl. 0:5836 36 1:1271 131 1:4300 144 1:4294 KCl . 0°3721 — 0°3129 _— 0:0053 — 0:0059 H,O . 1:44 — 1°44 = 1:4353 — 1°4353 Number of Water in Water in Water in molecules molecules molecules molecules NaCl. é 12°65 — 78:27 —_ 99°31 —_ 99:26 | KCl . 6°25 _ 21°73 — 0°37 _— 0°41 | 0.H . : 100 — 100 — 99:68 — 99°67 EXPANSION OF SALINE SOLUTIONS. EXPERIMENT V. ae Period of Period of Rist ; Mass in invapora- Water in invapora- Water in en grams tion in grams tion in grams days days } NaCl 1°1672 24 0:0034 56 0:0024 LiCl 0°8474 — 1°1506 — 11551 H,O 1-44 =F 11546! aa 1:1575 Number of Water in Water in | molecules molecules molecules NaCl 25 — 0:24 — 017 LiCl 25 — 79°90 — 80°22 oe AY obs = eee H,O 100 — 80714! _— 80°39 | EXPERIMENT VI. ae az 7 g Ba Bee Ho |ieee| Ae Bee Sf. |Sae] 2. = . ar : a) -m 2 |a% |ges| eo [Sea] e% Ieee) eo lees] s® 22) te: 43 a AS) NaCl | 0°5836 42 | 0:0031 77 =| 0:0019 171 | 0:0005 184 | 0:0006 LiCl, | 0°4237 — | 14459 — 1:4466 — | 14443 — | 14445 H,0 | 1:44 — 14490 — 14485 — | 14448 — | 14451 Sg AB AB £3 #8 wo = = = a 28 58 58 5s 58 Es 2s 25 2S ae mA a & FE =e NaCl | 12°5 — 0:22 — 0:13 — 0-03 — 0:04 | LiCl. | 12°5 — | 100-62 — | 100-46 — | 10030 — | 10031 H,0.} 100 — | 100-84 — 100-59 _ 100°33 — | 100-35 => 1 Part of the water was lost in closing the outer tube. Before opening the first time the tube was kept at 12° C. for three days, and before opening the second time -for six hours at 100° C. P2 212 REPORT—1886. Experiment VIL. 5 g a r=) 3 n oS Bm S oe nD hanged Mass in E 58 Water in Z z S Water in 3 ae Water in grams Bes grams Ba grams Bee grams eu Sas ce ae as x= eo NaCl. : 05836 62 0°4562 177 06219 191 0°6365 LiCl . : 0°4237 —_ 2°4154 — 2°2434 — 2°2284 0 | ese — | 2:8716 — | 28653 — | 28649 Number of Water in Water in Water in molecules molecules molecules molecules NaCl. F 6°25 -— 15°84 - 21°59 — 22-10 LiCl . : 6°25 a 83°87 — 77:90 = 17°38 H,O. . ~ 100 — 99°71 — 99°49 — 99-48 In discussing these experiments it is to be noted that when the two salts were potassic and sodic chlorides, the water was divided as nearly as possible equally between them, a little being, however, left in its small tube. The first weighing was not made until all the water seemed to be invaporated by the salts. When the two salts were sodic and lithic chlorides, the greater part of the water was given to the latter before en- closing in the large tube. Experiments I., II., and III. were made to discover the effect produced by increasing the relative quantity of water (an accident spoiled the experiment coming between II. and III.). It is evident from these experiments that sodic chloride invaporates water more powerfully than potassic chloride, for, as all the experiments show, the sodic solution increases in weight at the expense of the potassic. A preliminary experiment made this very apparent. The three tubes were: enclosed without dividing the water between the salts: after 24 hours the sodic chloride had begun to deliquesce, while the potassic chloride was quite dry; after 25 days about one-half of the water was invaporated, and, while the potassic chloride was only slightly moist, the sodic chloride was dissolved to a considerable extent. In repeating and extending our experiments this method (as above indicated) will be followed. Our chief object, so far, has been to determine how the water is divided between the two salts when a condition of equilibrium is reached. As might be expected, when the relative quantity of water is increased, the process is retarded, as the weaker solutions invaporate more slowly. But even with 32 molecules of water to 1 of each of the salts, the sodic chloride goes on steadily stealing water from the potassic (III.), although, after 151 days, it has succeeded in abstracting only 5 per cent. of the whole quantity of water. Experiment I., with the greatest relative quantity of salts, is not yet completed. The sodic chloride has, after 172 days, 86 per cent. of the water, and is still invaporating. In experiment II., which has lasted 290 days, the process of invaporation is apparently nearly complete, and the result is somewhat surprising. There are 100 molecules of water to 12°5 EXPANSION OF SALINE SOLUTIONS. 213 of each of the salts. The sodic chloride has nearly 93 per cent. of the water. It is possible that in course of time all the water may be attracted by the sodium salt; in which case we should conclude that the force in operation is different from chemical affinity. Experiment IV. was made to ascertain the effect of increasing the relative quantity of sodic chloride. The effect is to hasten the invapora- tion of water by this salt. After 144 days it has over 99 per cent. of the water. Now, it is known that even a saturated solution of sodic chloride gives off water-vapour to a dry atmosphere, so that in this final condition of experiment IV. the potassic chloride is in the presence of water-vapour. Tf the force of invaporation (which is probably intimately connected with the force of solution) were of the nature of chemism, it would cause com- bination of the potassic chloride with the water, and the condition of equilibrium would be one in which the relative quantities of water held by the two salts would be a measure of their affinities for water. The discussion of this point will, however, be better postponed until our ex- periments have been further extended. In experiments V., VI., VII., sodic chloride is pitted against the highly deliquescent lithic chloride. In V., with the same number of molecules as in I., the lithic chloride takes all but about one-third per cent. of the water; VI. and VII. show the effect of increasing the relative quantity of water. (Owing to the rapid deliquescence of the lithic chloride, the water is sometimes in slight excess of the theoretical quantity.) VI. shows that when the relative quantity of water is doubled, the lithic chloride still takes nearly all after 42 days, and quite all after 173 days. In this case 12°5 molecules of the salt have in- vaporated 100 molecules of water. When the relative quantity of water is again doubled, as in VII., an unexpected result is obtained. Asin V. and VI., the greater part of the water was given to the lithic chloride before enclosure. After 177 days, we find that the sodic chloride is gain- ing water, and this continues until in 129 days it has gained about 6 per cent. of the whole quantity. The condition of equilibrium is not yet reached, but there is clearly a limit to the quantity of water which the lithic chloride can hold against the attraction of the sodic chloride. There is a wide field of research opening up in the direction indicated by these few experiments. We shall extend the investigations to other salts, particularly chlorides, with a view to testing more fully the effect of increasing the relative quantities of water and of one of the salts ; and shall also attempt to determine the influence, if any, of temperature. With large proportions of water, experiments conducted at the tempera- tares at which eryohydrates are formed may yield interesting results. Report (Provisional) of the Committee, consisting of Professors McLeEop and W. Ramsay and Messrs. J. T. CunpaLL and W. A. SHENSTONE (Secretary), appointed to investigate the Influence of the Silent Discharge of Electricity on Oxygen and other Gases. The Preparation and Storage of Oxygen Gas in a Pure State. By W. A. SHenstone and J. T. CunpAtt. ¥or the purposes of this investigation it is necessary to provide oxygen and other gases in as pure a state as possible, in considerable quantities, 214 REPORT— 1886. and to preserve them for long periods without change, in order that the results of series of experiments made at intervals of several days or of weeks shall not be subject to unknown errors. In dealing with oxygen: the presence of nitrogen must especially be guarded against, for it com- bines more freely with oxygen (when the latter gas is present in excess) under the influence of the electric discharge than is commonly known to be the case. The mercury gasholder invented by Bunsen, which has been described in ‘Watts’ Dictionary’ and elsewhere, is hardly suitable for collecting gases in the rather large quantities that will be required. A similar but much larger gasholder, in which the mercury was replaced by sulphuric acid, has been tried. But, apart from the risk of air gaining admittance through the sulphuric acid, in which it is to some extent soluble, we find that even thoroughly washed oxygen, prepared from chlorate of potassium, carries with it a sufficient quantity of suspended matter to result in the presence of slight traces of chlorine tetroxide in the gas after the gasholder has been refilled several times. After the failure of this method of storing oxygen, an attempt was made to prepare it by electrolysis of dilute sulphuric acid almost saturated with chromic anhydride. When the superficial area of the negative electrode em- ployed greatly exceeded that of the positive electrode, pure oxygen was obtained in this way. When the evolution of oxygen was conveniently rapid, however, some bubbles of hydrogen escaped the oxidising action of the chromic acid and made their appearance. Finally, after the failure of an attempt to store pure oxygen by compressing it in iron bottles, the apparatus next described was constructed for producing the gas in smaller quantities as required. In the diagram, A is a cylinder having a capacity of one litre. It can be filled with mercury from a reservoir, not shown, through’ an india- rubber tube O, the entrance of bubbles of air carried by the mercury being prevented by the air-trap B. E is a flask connected to A by the tube JH. In Eis placed the material from which oxygen is to be produced. G contains phosphorus pentoxide! to remove moisture as far as possible from the gas before it is delivered through P into the receiver in which it is to be collected. Beyond G is one of Mr. Cetti’s patent vacuum taps. As this will not prevent the passage of air in the direction a to b, however, it is trapped at C. This trap can be filled with mercury to any desired level from a reservoir, as shown at Rand 8S. The only joints not made before the blowpipe are those shown at J, H, and F. These are all protected with mercury in the now familiar manner, the india-rubber connections being well lubricated and firmly bound with iron wire. The materials from which oxygen is to be prepared having been placed in E, and everything being in order, A is filled with mercury, ¢! is closed, ¢° and ¢3 are opened, and the apparatus is exhausted through P. Oxygen is then generated in E until the whole apparatus, including A, is filled. This process of exhausting and refilling is repeated at intervals of a few hours two or three times; and after the third operation a specimen may be collected and examined. Such specimens have been found to be very fairly satisfactory ; two samples of oxygen which had been confined in A for several weeks contained respectively 99°97 and 99-96 ‘ We find this substance to be admirably suited for removing suspended solid matter from gases. SILENT DISCHARGE OF ELECTRICITY ON OXYGEN AND OTHER GASES. 215 per cent. of oxygen; that is to say, 99°97 and 99:96 per cent. of the gas was absorbed by melted phosphorus in experiments made upon the two samples. When the apparatus is not in use the taps ¢', 2°, t? are closed, and the traps C and D filled with mercury to prevent the entrance of air. Oxygen may be delivered from A into any vessel by connecting it to P, exhausting it, #? being closed and Q being clamped to prevent the mercury from rising and filling C, and subsequently opening ¢°, when the gas will flow from A into the exhausted vessel. If ¢* be well ground it will resist the passage of air sufficiently to permit this to be done. _ If a delivery tube be attached to P, all air may be driven from it by flushing it with mercury before proceeding to deliver the oxygen in the usual manner. Thus waste of pure gas is avoided. ; The supplementary tap ¢! and mercury trap D are provided in order that accidental breakage of E on the application of heat (when fresh supplies of oxygen are about to be introduced into A) shall not admit air to the stock of oxygen already in A. When A, partly empty, is to be replenished, ¢? is closed, ¢! opened, and heat is applied to H, D being filled with mercury to the level S, through which the gas is permitted to escape. When E is thoroughly heated and a steady evolution of gas has set in, the oxygen is delivered into A. Thus if the replenishment of A be not too long delayed, no loss of time results from accidents to E, which can at any time be replaced and exhausted, whilst the oxygen remaining in A is still available for use, if the taps have been properly ground and are thoroughly lubricated. Of course the trap D, like C, must be closed by filling it with mercury at all times when escape of gas from E is not desired. When potassium chlorate is used as the source of oxygen, breakages, EH, are frequent. Silver oxide is much better, but it is troublesome to obtain it perfectly free from carbon dioxide. This has led us to employ a mixture of the chlorates of sodium! and potassium in molecular propor- 1 Chlorate of sodium is apt not to be pure; it should be carefully examined before it is used. 216 REPORT—1886. tions. We prepare the mixture by thoroughly mixing the recrystallised salts, maintaining the product in a state of fusion for some little while in an open dish, and subsequently powdering the solid produced on cooling. The melting-point of the product is considerably lower than that of either chlorate of potassium or chlorate of sodium; and it gives off its oxygen to about the same extent as chlorate of potassium ; that is to say, about one-third of it is easily expelled by a moderate heat. In conclusion, we are glad to be able to report that we have also con- structed most of the rest of the apparatus that will be required in the investigation that is before us. We hope, therefore, to make considerable progress before the next meeting of the Association. Nore.—October 10, 1886. Since this report was read we have suc- ceeded in connecting all the parts of the oxygen generator and holder before the blowpipe by a method described by one of us.! The only permanent mercury joint which remains is that at F, which is now specially protected against entrance of air. We may, therefore, expect to approach still nearer to the attainment of absolutely pure gases for our experiments. Report of the Commuttee, consisting of Professors TILDEN and ARMSTRONG (Secretary), appointed for the purpose of investi- gating Isomeric Naphthalene Derivatives. Tue study of isomeric naphthalene derivatives acquires importance from a variety of considerations, notably, from the very close relationship of naphthalene to benzene, which finds expression in the use of a simple hexagon to represent the latter hydrocarbon, the first mentioned being symbolised by a double hexagon formed of two benzene hexagons joined so that one side is common to both. In the case of benzene there are but three possible isomeric di-deriva- tives, according to the received theory of the constitution of this hydro- carbon ; the formation of these di-derivatives is governed by certain very simple ‘laws,’ the first of which may conveniently be termed the para-law, the second the meta-law: i.e., mono-derivatives containing a hydrocarbon radicle, one of the halogens, NH,, or OH invariably yield as chief product a para-di-derivative together with the isomeric ortho-di- derivative, the meta-di-derivative being formed, if at all, to but a small extent; whereas mono-derivatives containing NO,, SO;H, or COOH yield as chief product the meta-di-derivative, the para- and ortho-deriva- tives being formed in relatively small amount. Instead of three, naphthalene may give rise to ten isomeric di- derivatives ; it might therefore be expected that the laws of substitution for naphthalene would be proportionally less simple than for benzene: thus far, however, this has not been found to be the case, and many of the di-derivatives are to be prepared only by indirect methods. The para- law obtains equally in the case of naphthalene, being applicable to mono- derivatives analogous to those which in the benzene series obey the para- 1 Methods of Glass-blowing, pp. 62-3. ON ISOMERIC NAPHTHALENE DERIVATIVES. 217 Jaw ; but an interesting modification of the meta-law, exemplified by the behaviour of nitronaphthalene to bromine, nitric acid, and sulphuric acid, is to be noted: nitrobenzene under such circumstances would yield chiefly the meta-derivative, but in the case of nitronaphthalene the attack becomes shifted to the other nucleus, an a-a-derivative being formed as represented by the formule :— al! al NO, NO, NO, Bp 32 p B3 a‘! at Br NO, SO,H It would appear from our knowledge of the naphthalene derivatives generally that, as a rule, the a-hydrogen atoms (see figure) are those which become displaced, and that the (-atoms are affected only under somewhat exceptional conditions—as in the formation of (-sulphonic acids at high temperatures in presence of an excess of sulphuric acid— and when an amidogen or hydroxyl group is present. Hence the beha- viour of nitronaphthalene above referred to—the absence of similarity in the behaviour of the corresponding nitro-derivatives of naphthalene and benzene—is not improbably due to the existence in the case of naphthalene -of a higher law, which it may be permitted to term the ‘ alpha-law.’ As naphthalene-/3-sulphonic acid is the only A-derivative obtainable ‘directly from naphthalene, it appeared to be specially important to study the behaviour of the sulphonic derivatives in order to throw light on the formation of the $-monesulphonic acid; and it was to be expected that their investigation would furnish results of value in determining the laws -of substitution in the naphthalene series: moreover the ease with which the sulphonic radicle may be removed by hydrolysis renders the sulphonic derivatives especially suitable subjects of study. It will suffice to indicate briefly the character of the results hitherto obtained, reserving a full account for one of the chemical journals. The action of sulphuric acid in excess on naphthalene at a tempera- ture of 160°-180° has been studied by Ebert and Merz, who isolated two distinct acids—an a- and a (-disulphonic acid; Armstrong and Graham (‘ Chem. Soc. Trans.’ 1881, p.133 ; ‘ Berichte,’ 1882, p. 204) on re- examining the product obtained evidence of the presence of other disul- phonic acids, but after numerous trials the attempt to separate these was for the time abandoned, and attention directed to the preparation of disul- phonic acids by other methods less likely to give rise to secondary changes, such as readily occur on heating in presence of sulphuric acid. The result has been to establish the existence of two acids isomeric with the a- and B-acid of Ebert and Merz. y-Naphthalenedisulphonic Acid.—This appears to be the sole pro- ‘duct of the action of chlorosulphonic acid, CISO,;H, on naphthalene in accordance with the equation: C,,)H,+2SO,HCl = C,,H,(SO3H), + 2HCl. On distilling its chloride (m. p. 184°) with phosphorus penta- chloride, y-dichloronaphthalene is produced: therefore it may be con- cluded that y-naphthalenedisulphonic acid is an a-a-derivative of the same constitution as the nitronaphthalene derivatives formulated above. 218 REPORT—1886. _ Naphthalene-?-B-disulphonic Acid.—This acid is prepared by acting on naphthalene-G-monosulphonic acid with chlorosulphonic acid, and is cer- tainly the chief product, but it remains to ascertain whether an isomer is not produced simultaneously. It is at once converted by the action of bromine into a dibromo-monosulphonic acid; this behaviour renders it more than probable that the sulphonic radicle introduced by the agency of the SO;HCl assumes an a- position. The two acids prepared by Ebert and Merz by the action of sulphuric acid at a high temperature (160°-180°) are in all probability $-G-deriva- tives; they are both isomeric with the acids obtained by sulphonating naphthalene-a- and (-monosulphonic acids by means of SO,HC1: and this difference being established between the action of sulphuric acid and that of chlorosulphonic acid, it appeared desirable to ascertain the behaviour with SO;HCl of the naphthalene derivatives which had pre- viously been converted into sulphonic acids in the ordinary manner. The derivatives taken were a-nitro-, a-bromo-, a-chloro-, and (-chloro-naph- thalene: these have all been found to yield the same products when sulphonated by means of SO,HCI as on treatment with sulphuric acid- It is especially noteworthy, however, that from both a-bromo- and a-chloro-naphthalene an acid has been obtained in small quantity isomeric with the para-sulphonic acid previously known, and which forms the chief product ; this secondary product is probably also an a-a-derivative - like the primary product, but of the same series as the nitro-sulphonic acid formulated above. Two isomeric sulphonic acids also are obtained from /-chloronaphthalene. One, which is the chief product when SO;HCl is used, has been shown by Arnell to correspond to 0-dichloro- naphthalene, while the other corresponds to «-dichloronaphthalene, and therefore to the 3-disulphonic acid of Ebert and Merz, and to Schaefer’s betanaphtholsulphonic acid. Probably 6-dichloronaphthalene is the ortho- or 1:2 modification, and it may almost be regarded as established that «-dichloronaphthalene is a /3?-/35/-derivative ; so that, while a- and B-chloronaphthalene both behave in the manner to be expected from the analogy subsisting between benzene and naphthalene, evidence is afforded by the production of the a!-a‘’-derivative from the one and of the (3?-/33/- derivative from the other of the existence in the naphthalene molecule, in addition to the ‘ para-plane’ of benzene, of two ‘ planes of symmetry,’ as it were, in which an influence is exercised. The study of the action of bromine on aqueous solutions of the naph- thalene-sulphonic acids has also furnished results of interest. It has long been known that when naphthalene-a-sulphonic acid is treated with bromine the sulphonic group is displaced, dibromonaphthalenes being formed, whereas the (G-sulphonic acid is converted into a dibromonaph- thalene-sulphonic acid, the SO,H group retaining its place. It now appears that this behaviour of the two acids is fairly typical. Thus the two disulphonic acids of Ebert and Merz—which are doubtless both 6-6- derivatives—yield isomeric dibromonaphthaquinonemonosulphonates on treatment with bromine in excess—only one of the sulphonic radicles, viz., that which is contained in the C, group which is oxidised, being displaced. The isomeric dibromomonosulphonic acids obtained by treating (a) naphthalene 6-monosulphonic acid and (b) the ?-/3-disul- phonic acid above described with bromine are finally converted by the action of bromine into the same tetrabromonaphthaquinone, the sulpho- nic radicle being displaced, although in the /-position, in consequence ON ISOMERIC NAPHTHALENE DERIVATIVES. 219 of the oxidation to quinone of the C, group in which it is located. The y-disulphonic acid—which is doubtless an a-a-derivative—readily parts with both its sulphonic radicles, yielding as final products dibromonaphtha- quinone and what appears to be a hexabromonaphthalene. A further illustration of the stability of a (-sulphonic radicle is afforded by the behaviour of (Schaefer’s) betanaphtholsulphonic acid with bromine, the end product being a bromohydroxyquinonesulphonate. The results thus briefly recorded have been obtained with the assistance of Messrs. F. W. Streatfield, S. Williamson, and W. P. Wynne, B.Sc. It is anticipated that by the time of the next meeting of the Asso- ciation the investigation of isomeric naphthalene derivatives will have been carried sufficiently far to render possible a fairly complete statement of the laws of substitution in the naphthalene series in the shape of a final report. Report of the Committee, consisting of Professor T. McK. Huanzs,. Dr. H. Hicks, and Messrs. H. Woopwarp, E. B. Luxmoors,. P. P. Pennant, and Epwin Morgan, appointed for the purpose of exploring the Caves of North Wales. Drawn up by Dr. H. Hicks, Secretary. Tue explorations conducted by the Committee have been confined to the ‘caverns of F'fynnon Beuno and Cae Gwyn, in the Vale of Clwyd. These caverns had been explored in preceding years by Dr. H. Hicks and Mr. E. B. Luxmoore, some of the results being given in a paper communicated to the Geological Section of the Association in 1885, but more fully in a paper in the ‘ Quart. Jour. Geolog. Soc.,’ Feb. 1886. Among the remains discovered in these two caverns up to the com- mencement of the work this year there were over eighty jaws belonging to various animals, and more than 1,300 loose teeth, including about 400: rhinoceros, 15 mammoth, 180 hyena, and 500 horse teeth. Other bones and fragments of bones occurred also in very great abundance. Several flint implements, including flakes, scrapers, and lance-heads, were found in association with the bones. The most important evidence, however,. obtained in the previous researches was that bearing on the physical changes to which the area must have been subjected since the caverns were occupied by the animals. During the excavations it became clear that the bones had been greatly disturbed by water action, that the sta- lagmite floor, in parts more than a foot in thickness, and massive stalac- tites had also been broken and thrown about in all positions, and that these had been covered afterwards by clays and sand coutaining foreign pebbles. This seemed to prove that the caverns, now 400 feet above ord- nance datum, must have been submerged subsequently to their occupation by the animals and by man. One of the principal objects, therefore, which the Committee had in view this year was to critically examine those portions of the caverns not previously explored, so as to endeavour to arrive at the true cause of the peculiar conditions observed. Work was commenced at the end of May and carried on during the whole of June and parts of July and August. 220 - REPORT—1886. Oae Gwyn Cave. When the explorations were suspended last year it was supposed that we had just reached a chamber of considerable size, but after a few days’ work this year it was found that what appeared to be a chamber was a gradual widening of the cavern towards a covered entrance. The posi- tion of this entrance greatly surprised us, as hitherto we had believed that we were gradually getting further into the limestone hill. The rise in the field at this point, however, proved to be composed of a considerable thickness of glacial deposits heaped up against a limestone cliff. As the materials covering the bone-earth within and at the entrance were chiefly sands and gravels, it was found necessary to suspend operations in that direction and to ask the landlord (E. Morgan, Esq.) for permission to open a shaft directly over this entrance from the field above. As this t. 6 in. —~—-—Brown clay with boul- ders, 2 ft. 9 in. ——— Stiff reddish clay with =S boulders, 2 ft. 3 in. SS —- —- — — — — Sand, 2 in. SSS Purple clay, 10 in. ae oe Geer ta Sand with boulders, 1 ft. 7 in. ee Gravelly sand with boul- ders and bands of purple clay, 2 ft. 2 in. ed Sandy gravel, 2 ft. i Fine banded sand, 1 ft, 5 in. ——--— -Red laminated clay and bone-earth, with angu- lar fragments of lime- stone and a few boul- ders, Contained also a flint-flake, from 2 to 5 ft. A, Carboniferous limestone. 4 Position of the flint flake. Fie. 1.—Section at New Entrance to Cae Gwyn Cave. necessitated the removal of a considerable surface of land and caused some damage to the field the Committee feel that their special thanks are due to Mr. Morgan for his kindness in so readily acceding to their appli- cation. This shaft, as at first opened, was about nine feet across at the surface and over five feet at the bottom. It was subsequently widened at the bottom in consequence of some falls, and the lower part, excepting at one point, had to be carefully faced with timber. Theupper part is now much widened and sloped. The shaft was about twenty feet in depth, and the deposits as shown in fig. 1 were made out init. These were care- fully measured by Mr. C. E. De Rance, F.G.S., Mr. Luxmoore, and the writer during the prosecution of the work. Below the soil, for about eight feet, a tolerable stiff boulder clay, containing many ice-scratched ON THE CAVES OF NORTH WALES. 227 boulders and narrow bands and pockets of sand, was found. Below this there were about seven feet of gravel and sand, with here and there bands: of red clay, having also many ice-scratched boulders. The next deposit met with wasa laminated brown clay, and under this was found the bone- earth, a brown, sandy clay with small pebbles and with angular fragments of limestone, stalagmite, and stalactites. On June 28, in the presence of Mr. G. H. Morton, F.G.S., of Liverpool, and the writer, a small but well- worked flint-flake was dug up from the bone-earth on the south side of the entrance. Its position was about eighteen inches below the lowest bed of sand. Several teeth of hyena and reindeer, as well as fragments Sand Laminated clay Bone earth F (Bandy clay with pebbles, &c.) Gravel z . - (Mainly local materials) Sandy clay Laminated clay Bone earth - F (Sandy clay with pebbles, &c.) Gravel * (Mainly local materials) Fic. 3.—Section in Cae Gwyn Cave, about 16 feet from the New Entrance. of bone, were also found at the same place, and at other points in the shaft teeth of rhinoceros and a fragment of a mammoth’s tooth. One rhinoceros tooth was found at the extreme point examined, about six feet beyond and directly in front of the entrance. It seems clear that the contents of the cavern must have been washed out by marine action during the great submergence in mid-glacial time, and that they were afterwards covered by marine sands and by an upper-boulder clay, iden- tical in character with that found at many points in the Vale of Clwyd and in other places on the North Wales coast. Figs. 2 and 3 ex- plain the order of the deposits as found within the cavern. Fig. 3 222 REPORT—1886. was taken at a distance of about sixteen feet from the entrance at the shaft, and fig. 2 just within that entrance. The order in that por- ‘tion of the cavern examined this year accorded in the main with that found during the previous researches, but within the entrance there was a greater thickness of sand, less of the laminated clay, and more bone- earth than in the other parts of the cavern. The bone-earth seems to diminish in thickness rather rapidly outwards under the glacial deposits, but it was found as far out as the excavations have been made. Here the bone-earth rests directly on the limestone floor, with no local gravel between, as in the cavern. It would be interesting to know how far the cave earth extends under the glacial deposits, but this could only be ascertained by making a deep cutting through the terrace of glacial deposits, which extends for a con- siderable distance in a westerly direction. The glacial deposits here are undoubtedly in an entirely undisturbed condition, and are fuil of smooth and well-scratched boulders, many of them being of considerable size. Among the boulders found are granites, gneiss, quartzites, flint, felsites, diorites, voleanic ash, Silurian rocks, and limestone. Silurian rocks are most abundant. It is clear that we have here rocks from northern sources, -along with those from the Welsh hills, and the manner in which the lime- stone at the entrance to the cavern in the shaft is smoothed from the north would indicate that to be the main direction of the flow. The marine sands and gravels which rest immediately on the bone-earth are probably of the age of the Moel Tryfaen and other high-level sands, and the overlying clay with large boulders and intercalated sands may be con- sidered of the age of the so-called upper-boulder clay of the area. The latter must evidently have been deposited by coast-ice. Whether the caverns were occupied in pre- or only in inter-glacial times it is difficult to decide, but it is certain that they were frequented by pleistocene animals and by man before the characteristic glacial deposits of this area were accumulated. The local gravel found in the caverns, underlying the bone-earth, must have been washed in by streams at an earlier period, probably before the excavation of the rocky floor of the valley to its present depth. From the glacial period up to the present time excavation has taken place only in the glacial deposits, which must have filled the valley up to a level considerably above the entrances to the caverns. The characteristic red boulder clay with erratic blocks from northern sources is found in this area to a height of about 500 feet, and sands and gravels in the mountains to the S.E. to an elevation of about 1,400 feet. The natural conclusion therefore is that the caverns were occupied by an early pleisto- cene fauna and by man anterior to the great submergence indicated by the high-level marine sands, and therefore also before the deposition of the so-called great upper-boulder clay of this area. As there is no evidence against such a view it may even be legitimately assumed that the ossi- ferous remains and the flint implements are of an earlier date than any glacial deposits found in this area. Ffynnon Beuno Cave. This cavern, which yielded the greatest number of bones in the previous researches, has now been cleared out in all those parts where the deposits appeared to have been undisturbed by man. A considerable addition to the number of bones and teeth has been made this year, but no new forms have to be added to those already mentioned. ON THE CAVES OF NORTH WALES. 223 The animal remains found in both caves, as defined by Mr. W. Davies, F.G.S., of the British Museum, comprise teeth and bones of eleven genera and sixteen species, as shown by the annexed list :-— Lion (Felis leo, var. spelea). Bovine (Bos ? Bison ?). Wild cat (F. catus ferus). Great Irish deer (Cervus giganteus). Spotted hyena (H. crocuta, var. Red deer (Cervus elaphus). spelea). Roebuck (C. capreolus). Wolf (Canis lupus). Reindeer (C. tarandus). Fox (C. vulpes). Horse (Equus caballus). Bear (Ursus, sp.). Woolly rhinoceros (R. tichorrhinus). Badger (Meles tazus). Mammoth (Elephas primigenius). Wild boar (Sus scrofa). Fourteenth Report of the Committee, consisting of Professors J. PRESTWICH, W. Boyp Dawkins, T. McK. HuGueEs, and T. G. Bonney, Dr. H. W. Crossxey (Secretary), and Messrs. C. E. DE Rance, H. G. Forpuam, J. E. LEE, D. Mackintosu, W. PENGELLY, J. Prant, and R. H. Tippeman, appointed for the purpose of recording the position, height above the sea, lithological cha- racters, size, and origin of the Erratic Blocks of England, Wales, and Ireland, reporting other matters of interest connected with the same, and taking measures for their preservation. THE attention of the Committee has been called by Professor Hughes to boulders near Kendal and Settle, which are perched upon pedestals of limestone, and are striated in the direction of the main iceflow of the district, whereas the surface of the surrounding block bears no traces of glaciation. These boulders appear to have been transported to their present position, and placed upon the bare striated rock under exceptional local conditions, and the pedestals appear to be portions of the surrounding rock protected from denuding agents by the overlying boulder. The Committee hope to be able to secure the preservation of these boulders. Mr. Plant reports a remarkable assemblage of blocks in the drift in the valley of the Soar, near Leicester. Excavations to the depth of 30 feet have been made in various parts of the river valley, and after passing through the alluvium the boulder clay has been reached. Thousands of erratics have been found. Half of the erratics were from the Charnwood district, and of the remainder a great many were from the Permian sand- stones and Carboniferous rocks of the Ashby coalfield, with blocks of mountain limestone from Staunton, Harold, and Breedon—a distance of fifteen to eighteen miles north-west. The rest are from the east side of the Pennine chain, forty to fifty miles distant north-east. On a ridge near the Victoria Road, south of Leicester, upwards of 200 erratics have been uncovered. Millstone grit, mountain limestone, and lower oolite blocks, more or less striated, were found mixed with Charn- wood syenites. The height of the ridge is 260 feet above the sea, and 110 feet above the present valley of the Soar. 224 REPORT—1886. In the drift at Clarendon Park, south-east of Leicester (310 feet), many hundreds of boulders have been exposed during recent excavations. Some of the millstone grit blocks must have travelled forty or fifty miles. Lumps of coal were also found which must have travelled seventeen miles from the north-west. Dr. Crosskey and Mr. Fred W. Martin record a group of boulders found on the road between Shiffnal and Tong. This group consists of a fine collection of Lake rocks and Criffel granites. They evidently travelled together to their present position. A catalogue of these boulders will be given in the next Report. The Committee call especial attention to the grouping of the erratics found in different districts, and also to the evidence presented that the Charnwood district was the centre of local ice action. On the Glacial Phenomena of the Midland District. By Dr. Crosskey. The object of the paper is to indicate some of the problems raised by the glacial phenomena of the Midland district, and point out the typical sections by which they are illustrated. It is necessary to avoid the confusion caused by the vague use of the term ‘boulder clay.’ Seven or eight different beds have, in fact, been designated by the term ‘boulder clay’; and it has become absolutely necessary to separate the deposits from each other and record their distinct characteristics. The first question is, What are the lowest deposits of glacial age in the Midlands ? What is found at the base of the masses of clay, sand, and gravel scattered over the district? Is there any deposit of the age of the lower boulder clay or Till of Scotland ? The lowest of the beds known in the Midlands may be seen at California, near Harborne. It consists of a. thick clay filled with angular and striated erratics of Welsh origin, com- pactly pressed together and intermixed with fragments of rocks from the locality, and is about 480 feet above the sea. This boulder clay is fol- lowed by a series of sands and gravels, which are covered by a consider- able mass of tenacious ‘india-rubber’ clay with erratics scattered somewhat sparsely through it ; and this upper clay is capped by a second series of sands and gravels, more or less intermixed with clay. The lower boulder clay is more intensely glacial in character and more analogous to the Scotch Till than any other yet described in the district. Whatever its origin, it belongs to the period of extreme ice action. Of another type of boulder clay an example may be seen at Wolverhampton. This boulder clay contains a mixture of erratics. A large number of its erratics are from the Lakes and some are from Scotland, while flints from the east also occur. In the ordinary Scotch Till, when the trend of the valleys radiating from the central eminences is followed, the course over which the erratics travelled can be traced. But the Wolverhampton boulder clay marks the meeting-place of erratics from various quarters. An example of a third series of beds, possibly belonging to the same age, “may be seen in a cutting at Soho, near Birmingham, where clays and sands, containing erratics, are strongly contorted. While the material of these beds is probably lower glacial, the contortions must have been sub- sequent to its deposition, and indicate the work of another age. How far this series of lower beds may be attributed to the action of land ice or of floating ice is an open question. ON THE ERRATIC BLOCKS OF ENGLAND, WALES, AND IRELAND. 225 The second question is, Are there any Midland glacial beds referable to the period of glacial subsidence? Two series of deposits and of erratics also have to be taken into account—those representing the period of subsidence and those representing the period of re-elevation. During the gradual subsidence of the ice-covered land, erratics would be floated off as its various points became successively immersed, and deposits would also be formed at the sea-bottom, These middle glacial clays, sands, and gravels occur at various points. Fossils have been found near Welling- ton, Shropshire, Astarte borealis being among them. In beds at Lilles- hall, Salop (463 feet), three arctic species occur. The upper boulder elay (worked for bricks through the district) contains erratics, which appear clearly to have fallen into it, and altogether differs from the lower bed. It is a mass accumulated during subsidence. The third question is, What signs are there of ice action during the re-elevation of the land? During the process of re-elevation the marine clays and sands would be washed and re-sorted by currents, and the sea would be covered by icebergs floating away from our present mountains, which would then be islands in a glacial sea. The Midlands now consti- tute atable-land. This table-land would at this period be the shallow part of the sea against which icebergs would be stranded. At Icknield Street, Birmingham, the rock has been smashed and a large collection of Welsh erratics flung against it. One of the most marked characteristics of this period would be the distribution of fragments from the present highlands of the Midlands. The present highlands of the Midlands would then be low-lying islands, which would be covered with ice. By the breaking away of the ice-foot around them blocks would be distributed over the sea-bottom in their immediate neighbourhoods. Rowley Hill blocks are found eight or nine miles off. Boulders torn from Charnwood are abun- dantly spread over many acres for many miles, and must have been carried by local ice. Fragments from the Malvern Hills have been scattered through the plains around. Erratics from the mountains of Wales, the Lakes, and Scotland also must have been brought by the icebergs travelling from those centres as the mountains became higher and higher. The work done during re-elevation must be distinguished from that done during subsidence. The surface erratic blocks, so remarkably developed in the Midlands, cannot be roughly explained away in connection with any one portion of the epoch, and present complicated problems. Some erratics now upon the surface may have been originally imbedded in clays and sands, which have been washed away, and have really belonged to the ancient boulder clay. Erratics were dropped by icebergs during the submergence of the land when there was a succession of ever-varying island boundaries. Erratics were also dropped during re-elevation when there was an ever- increasing mou1 tainous area from which they could be derived. Facts have to be noted in connection with the following points :— (i.) The origin of the erratics—Some were derived from a distance— 1.e.,from W. Scotland, the Lakes, and Wales. Others were of local origin and of local range, as from Charnwood, Rowley, and Malvern. Others mark the pushing in of the débris derived from chaiky boulder clay. (ii.) The heights of erratics above the sea.—Erratics are found in the Midlands on heights extending from comparatively low levels to 900 feet. They could not therefore have been deposited in their present positions at one and the same time. They must indicate a succession of events. 1886. Q 226 REPORT—1886. (iti.) The position of definite groups of erratics in relation to each other. For example, around Birmingham and Bromsgrove the erratics are chiefly Welsh ; but a vast collection of Scotch and Lake erratics lies right across the path the Welsh erratics must have taken. (iv.) The distribution of erratics in relation to the physical geography of the district.—On the table-land north of Wolverhampton, Lake and Scotch rocks are intermixed, the Scotch being abundant. Journeying westward the intermixture becomes more complete. The stream of Welsh erratics crosses the northern stream ; then the Welsh erratics be- come more and more abundant, only a few northern stragglers being found, until at Clent and Bromsgrove not a single erratic of granite has yet been found among thousands of Welsh origin. Taking a line of country in another direction—between Wolverhamp- ton and Stafford—cretaceous and jurassic débris appears. The same débris may be noted pushing itself around Coventry. (v.) The distribution of erratics in relation to the physical geography of England and Wales.—The various Midland glacial deposits cannot be understood apart from a careful examination of their relation to the various levels of the plains, highlands, and mountains of the whole of the surrounding country. Report of the Committee, consisting of Mr. H. Bavrrman, Mr. F. W. Rupwer, Mr. J. J. H. Treaty, and Dr. Jonnsron-Lavis, for the Investigation of the Volcanic Phenomena of Veswrius and its neighbourhood. Drawn wp by H. J. Jounston-Lavis, M.D., F.G.S. (Secretary). Dorine the last twelve months Vesuvius has shown slight variation from the state of activity which it has exhibited during the past few years. Lava has from time to time found fresh openings around the higher parts of the great cone, and has flowed from them one after another, so that the intervals of time during which no fluid rock was issuing were very short. This regularity of action was, however, broken on June 28, when, a lower outlet being formed on the eastern side of the great cone, the consequent depression of the lava level in the main chimney resulted in the crumbling in of the cone of eruption, which before this date had attained very considerable dimensions. During the whole month of July the ash-forming stage prevailed, so that the usual continuous vapour and lava-cake ejections were replaced by intermittent puffs of ash and sand- laden vapour and accompanied by the ejection of stones. The craterial cavity, which is double or bifurcated, which has been excavated within the cone of eruption, is of very considerable size, being about 60x80 metres in diameter. The lava that issued during July, on two occasions entirely crossed the Val d’Inferno, and following one of the wooded glens or ravines on the property of the Prince of Ottajano destroyed a considerable number of trees. These different changes will be made apparent by the photographs taken by the reporter and exhibited at the meeting. b | In a paper read before the Royal Society the writer has given compara- tive curves of the activity of Vesuvius, the barometric pressure, and the ON THE VOLCANIC PHENOMENA OF VESUVIUS. 227 rainfall, together with the phases of the moon, deduced from observations extending over two years. The method of registering the different degrees of activity! is that described in the report of this Committee last . year. The results seem to indicate a distinct relationship between barometric pressure and the violence of the explosions, or, in other words, the ebullition of the lava. On the contrary, the rise and fall of lava level within the chimney in relation to tidal action set up within the magma is doubtful, though some coincidences are remarkable. The short time during which observations have been carried on, and the facility with which any true rise and fall of lava may be masked by other causes, necessitates the study of the subject for some years longer. Observations during the past fourteen months go to confirm the conclu- sions arrived at in the paper above mentioned. The fourth sheet of the geological map of Monte Somma and ‘Vesuvius has been completed, and is exhibited at the meeting. Although small—a good portion being sea—much patience and time were necessary, owing to the area being thickly inhabited and the ground broken up by numerous small gardens, &c., enclosed within high walls. The geology of the region mapped in this sheet is slightly more difficult to work out than that included in the third sheet (exhibited at the last meeting), and is much more intricate in detail. Sheet 5 is in considerable part mapped, and the reporter had hoped to have completed it for exhibition at the present meeting beside Sheet 4, but he was prevented by a number of family troubles, which forcibly diverted his attention during the spring and early summer. The reporter regrets to announce that the ‘Giornale del Vesuvio,’ containing a diary of all the observations made during the last four years, and which should have appeared eight months ago, is not yet published. This delay, however, is not the fault of the author. Proofs of nine of the illustrations in phototype are exhibited at the meeting. The present year is remarkable for the chances it affords for studying the subterranean structure of the Campi Phlegrei and the volcanic region around Naples. The great main drain, which is to convey the sewage of Naples to the Gulf of Gaeta, will traverse the region west of Naples on a line running nearly east and west. Before, however, constructing this sewer a series of five borings have been made to test the ground to be cut through. Observations on the water level, tem- perature, and presence of volcanic gases were made. Although these borings in themselves have brought no remarkable fact to light, they will, combined with the deep artesian well at Lago Fusaro, form important documents for the study of the structure of such a complicated region. Five other borings on or near the renowned Starza or foreshore of Pozzuoli, on the works of Sir W. Armstrong, Mitchell, & Co., are in- teresting as being within a few hundred yards of the celebrated so-called Temple of Serapis. Details of these, two of which are on the beach and the other three at varying distances out to sea, will be published together with others being made. For the present, however, it may be said that these borings fully confirm the opinions generally held as to the oscilla- tions of the ground in this district. 1 And not of the quantity of vapour, as erroneously stated in the Abstract, Proc. Roy. Soc. No. 243, 1886. Q2 228 REPORT—1886. The new Cumana Railway, which is to connect Naples with Baia and Fusaro, in the first part of its course traverses a tunnel of about a mile and a half long, which is cut in the body of the escarpment which consti- tutes the rocky amphitheatre backing the west end of Naples. Until the present, this was supposed to be composed of a moderately uniform mass of pelagonatised basic marine tuff. Under the middle of the Corso Vitt. Emanuele and the Via Tasso the edge of a trachyte flow was encountered and traversed for a distance of over 70 metres. The rock the reporter has not yet examined microscopically, but it very much resembles a simple non-quartziferous, and more probably a sodalite trachyte. This line of railway will traverse a number of tunnels and cuttings in the Campi Phlegrei, and will have to traverse the hot hill which backs Baia, and will no doubt present various uncommon engi- neering difficulties, besides giving some useful information bearing on terrestrial physics. Lastly, a deep well at present being bored at Ponticelli, on the out- skirts of Naples towards Vesuvius, has already been carried to a depth of over a hundred metres, and during the latter half of this a series of leucitic Java streams were traversed, showing the great distance to which the old flows from Monte Somma reached, and also, that either great depression of land has taken place, or that Monte Somma once formed a volcanic island. As these different’ works progress they are and will be kept under watch, and all that is interesting will be recorded. The reporter has partly prepared the first instalment of a study of the ejected blocks of Monte Somma. He has left this subject dormant for two reasons: first, the want of further chemical apparatus for the execution of many analyses required; and, secondly, it was considered necessary to visit the ancient volcanic region of the Fassathal, in the Tyrol, to study some points that could not be worked at in an area covered by thick deposits from recent voleanoes. The striking analogy between the products of volcanic action and the contact metamorphism in the Southern Tyrol and at Vesuvius is so remarkable that many interesting facts will come out of the study of these two regions in relation to each other. The reporter, having had the opportunity this summer of visiting the Tyrol, hopes this winter to be able to study the ejected blocks of Monte Somma, which, from the absence of serpentini- sation and other secondary changes, will throw much light on the origin and mutual relations of many varieties of igneous and metamorphic rocks. and the genesis of numerous minerals. The reporter has treated during the past year various questions bearing on Vesuvius and its neighbourhood in papers before the Royal Societies of London and Dublin, the Royal Microscopical Society, the Geologists’ Association, and the Accademia Oronzio Costa, besides various. articles in ‘Nature’ and other periodicals. The reporter’s ‘ Monograph of the Earthquakes of Ischia,’ after many vicissitudes, was published at the end of 1885. ON THE FOSSIL PHYLLOPODA OF THE PALHOZOIC ROCKS. 229 Fourth Report of the Committee, consisting of Mr. R. Ernerwee, Dr. H. Woopwarp, and Professor T. Rupert Jones (Secretary), on the Fossil Phyllopoda of the Paleozoic Rocks. Genera and Species. Genera and Species. 1. Ceratiocaris leptodactylus (M‘Coy). 18. C. oretonensis and C. truncata, H. W. 2. C. Murchisoni (Agass.). 19. C. solenoides (M‘Coy), and C. gobii- 3. C. gigas, Salter. ' formis, J. & W. +. C. valida, nov. 20. Emmelezoe elliptica M‘Coy ; E. tenui- 5. C. attenuata, nov. [? tyrannus, Salt.] striata, nov.; E. crassistriata, . C. canaliculata, nov. nov.; E. Maccoyiana, nov. a. C. Halliana, nov. 21. Xiphocaris ensis (Salter). 8. C. Pardoeana, La Touche. 22. Physocaris vesica, Salter. 9. C ludensis, H. W. 23. C. ? spp. 10. C. robusta, Salter, C. lata, angusta, | 24. CO. ? longicanda (D. Sharpe). and minuta, novv. 25. Ptychocaris simplex and Pt. parvula, il. C. papilio and C. stygia, Salter. Ovak 12. C. laxa, nov. f 26. Cryptozoe problematica, Packard. 13. C. Salteriana, J. & W. 27. Geological localities of Mr. J. M. 14. C. cassia, Salter, C. cassioides, nov. Clarke’s fossil Phyllopods. 15. C. compta, nov. 28. List of British Paleozoic Phyllo- 16. C. inornata, M‘Coy. carida described in the Third 17. C. Ruthveniana, nov. and Fourth Reports. INTRODUCTION. Since the publication of the Third Report on Paleozoic Phyllopoda (Brit. Assoc. Report’ for 1885)' we have examined many addi- tional specimens in the Musenms of the Edinburgh and Glasgow Uni- versities, and in the Braidwood Museum belonging to Dr. J. R. S. Hunter, of Braidwood, near Glasgow. Mr. James Thomson, F.G.S., has given us a quantity of nodules, containing remains of Ceratiocaris, from the Lesmahago district; and other friends have lent us several interesting specimens. We have also again critically examined the fossils enumerated, under ‘ Ceratiocaris,’ in the ‘Third Report,’ and, having had numerous finished drawings carefully made for illustration of a forthcoming monograph for the Palzontographical Society, we have been able to compare them more perfectly and with more precise results. Thus we find that— 1. Ceratiocaris leptodactylus (M‘Coy), see ‘Third Rep.’ pp. 11-14, as known by its caudal appendages (Cambr. Mus. a/923, a/924, and a few others), is distinct from C. Murchisoni, M‘Coy, both as to size and proportions. We have traced two rows of pits (bases of prickles) on a/924, as exposed. Some similar caudal appendages, M.P.G. 32, occur in the Lower Wenlock rock of Helm Knot, Dent, Yorkshire. _ 2. CG. Murchisoni (Agass.), founded on some specimens figured in “Sil. Syst.’ and ‘ Siluria,’ but unfortunately lost (‘Third Rep.’ p. 11, &c.), is represented by several analogous fossils, such as Oxford Mus. B and C; Ludlow Mus. C; M.P.G. 23 and 23. We find only one row of pits on the styles, as exposed. We have been unable to determine its carapace ; but a fragment lying in the same slab with 23 may belong to it. The cara- paces formerly assigned to O. leptodactylus and C. Murchisoni (‘Third Rep.’ pp. 12, 15) are now regarded as belonging to distinct species. 3. The caudal appendages of C. Murchisoni have a slight curvature ; there are others much like them, but straight, and associated with a Jarge ultimate segment, much broader than that in M.P.G. 32. (For 230 REPORT—1886. instance, Oxford Mus. F; M.P.G. X 4+; Ludlow Mus. T.) One of these (X 4) has been labelled C. gigas by Mr. Salter; and therefore we adopt that name. 4. The specimens from the Wenlock beds of Dudley and Kirkby Lonsdale, described and figured in the ‘ Geol. Mag.’, 1866, p. 204, pl. 10, figs. 8 and 9, as belonging to CO. Murchisoni (‘Third Rep.’ p. 12), are too thick and strong for that. species, and the Dudley example (fig. 8) has different proportions. We propose to distinguish them as C. valida. 5. Some abdominal segments (Oxford Mus. E; Ludlow Mus. L; B.M. 39403; M.P.G. 23 and 23; ‘Third Rep.’ p. 20, &c.), narrow in proportion to those in one other specimen marked 23, and referred to C. Murchisoni, and very much narrower and smaller than in C. gigas, we separate as a new species, to be called C. attenuata. They have straight styles and stylets, much shorter than in either of the foregoing. 6. Two small specimens of crushed telsons (one in Mr. Cocking’s collection, and the other M.P.G. X 4, both from the Ludlow series), probably smaller than C. Murchisoni, have a fluted or channelled sculp- ture on their upper part, instead of either wrinkles or leaf-pattern ; hence they may be regarded as belonging to a distinct form, for which the name canaliculata will be convenient. 7. One fine large carapace (M.P.G. X +) and others smaller and less definite in some respects (M.P.G. X4+; X34; X34; Ludlow Mus. A; Oxford Mus. K & J), and associated with segments and appendages, we regard as distinctive of a new species, though hitherto referred to CO. leptodactylus (‘Third Rep.’ pp. 12,15). \ The test appears to have been of an unusually solid consistency. These carapaces in some instances have been much modified by pressure, but we trace a close similarity throughout the series, allowing for probable differences of age. The shape approximates to that of Dr. James Hall’s species C. acuminata and F. Schmidt’s C. Noetlingt (‘Third Rep.’ p. 30). There are marked differences, however, and we intend to designate this form C. Halliana, in honour of our old friend, who began working at these Phyllocarida as early as 1852. A perfect specimen of C. acuminata, Hall, has been lately described and figured by Dr. Julius Pohlman in the ‘Bulletin of the Buffalo Society of Natural Sciences,’ vol. v. No. 1, 1886, pp. 28, 29, pl. 3, fig. 2. Its caudal appendages are much like those of C. papilio and C. stygia, the style being relatively short, and the stylets broad and blade-like. The appendages in M.P.G. X41, X34, and Ludlow Mas. A are different from these, being thinner, tapering slowly, and pitted in at least one row, as exposed. 8. C. Pardoeana, La Touche. Two carapaces with segments and parts of appendages from Ludlow (Ludlow Mus. B and D; ‘Third Rep.’ p. 12) differ from any other form. One of them (B), with a wrong caudal appendage attached to it, in the Ludlow Museum, has been labelled ‘ C. Pardoensis,’ and as such is referred to in J. D. La Touche’s. ‘Guidebook to the Geology of Shropshire. We retain this name (altering the termination, as it refers to a person, and not a place) for the two carapaces here referred to. One of them (B) is of special interest as having its rostrum still in place. 9. The fine large specimen of C. ludensis, H. W. (‘ Third Report,’ p- 16), has been again carefully studied, and we find reason to believe that the caudal appendage which appears longest in the fossil was not ON THE FOSSIL PHYLLOPODA OF THE PALHOZOIC ROCKS. 231 really the longest, or the true telson, but was one of the ‘laterals’ or stylets. Hence the whole animal was probably much longer than our former estimate made it. 10. C. robusta, Salter (‘Third Report,’ p. 24), being based merely on some small caudal appendages (Cambridge Museum a/925 and a/926) without carapaces, is troublesome and unsatisfactory to deal with. We find some equivalent styles and broad blade-like stylets, like long scalene triangles, in OC. papilio, stygia, acuminata, &c.; but none of these seem small enough for the several little sets of trifid appendages, more or less perfect, which we have met with. C. robusta takes in some of these; but Oxford Mas. T is relatively broad, and might be termed lata; B.M. 08878, from Muirkirk, has very narrow members (angusta) ; and one set in the Owens College is so neat, symmetrical, and small that it might be called minuta. 11. The specimens Ludlow Mus. S. and M.P.G. X41,? have each a long style and a strong stylet attached to a broken ultimate segment, and were regarded as var. longa in the ‘ Third Report,’ p. 25. Although not showing the lattice-pattern so often seen on the segments of C. papilio and C. stygia, they may well belong to one of those species, and the or- nament may have flaked off from the ultimate segment. The study of C. papilio and stygia (‘Third Report,’ pp. 16-20) we have not yet ex- hausted by any means. We know, however, that the abdominal segments were delicately sculptured with leaf-like or lattice-pattern ornament, the points of the triangles pointing upwards, or rather backwards, towards the carapace, and one limb of the triangle, where free, ranning downwards and outwards in the other direction. These oblique lines are often visible when the triangles have disappeared from wear or decomposition. Among many others the segments M.P.G. X,!,!; B.M. 41900: Oxford Mus. A and H exhibit fine examples of this leaf-like ornament; and it is visible in several more complete individuals in those collections. In the Braidwood and Glasgow Museums numerous specimens show it well. See also ‘Third Report,’ p. 31. 12. A small and very delicate specimen, B.M. 59648, has a thin sub- ovate carapace, with excessively fine parallel longitudinal strie, and shows 14 or 15 segments, some within and five outside the carapace, ending with a neat trifid set of appendages. This differs from any other form we know ; and probably some small loose bodies, of numerous segments, occurring in the Lesmahago shales (‘ Third Report,’ p. 20) may be of the same species. Its looseness of structure would suggest the name laza. 13. Of C. Salteriana, noticed as a new species in the ‘ Third Report,’ p- 28, we have not yet seen any additional specimens. 14. The specimens which we referred to in the ‘Third Report,’ pp. 23 -and 24, as C. cassia, Salter, are separable into twoforms. O. cassia proper is recognised on an interesting slab, of which one counterpart is in the Ludlow Museum (E and F) and the other in the Museum of Practical Geology ac Jermyn Street, London (X1). The other somewhat similar, but larger and otherwise different, specimens are not unlike in the characters of the carapace, but they have more abdominal segments exposed and proportionally longer caudal appendages—M.P.G. X J5; B.M. 39400; Ludlow Mus. K; Oxford Museum Land Q. These might be conveniently named C. cassioides. In all the specimens of both kinds the carapace has been apparently thin and tough, so as to allow of their being crumpled very much. This 232 REPORT—1 886. Be, aia condition and the presence of harder parts of their internal organs beneath give rise to various tubercular irregularities of the surface, in some cases simulating ocular tubercules. There are, however, no real eye-spots. There may have been irregularities of the surface, due to the attachment of the muscles of the jaws within the body. 15. An ovate carapace, represented by a mere film, and five abdominal segments, with a neat trifid tail, all flattened but very distinct, have no close ally among the known forms. The segments are delicately striate, with oblique lines on each side, suggesting the name compta, which we propose for this specimen—Ludlow Museum, EH. To OC. inornata, M‘Coy (‘Third Report,’ pp. 20, 21), we have nothing to add, except that some large specimens (so named, Cambridge Mus., 6/35) have a greater proportional depth (height) at the ventral border than smaller individuals, and yet have the same general outline and pos- terior slope, as well as the longitudinal lineate ornament. The presence of this sculpturing is not in accordance with the trivial name. These large specimens may belong te C. stygia. In the Cambridge Museum is a specimen (6/36) of two abdominal segments, with a style and a stylet in good preservation, being convex and not injured by pressure. The penultimate segment is smooth, but shows faint traces of oblique lines; the ultimate is quite smooth and cylindrical; the telson (style) is attached by an apparently rounded joint; and the two uropods much resemble some of those referred to C. robusta. This specimen is from Benson Knot, and is labelled C. inornata ; but the evi- dence of its specific relationship is supported only by its having been found in the same rock, and by its size suiting the large form of C. inor- nata ? (b/35). It belongs possibly to C. stygia. 17. From the list for (. inornata, given in the ‘Third Report,’ we have to remove one of the specimens found at Benson Knot, and marked ‘44342’ in the British Museum, being decidedly different in outline (more ovate), though similarly marked with longitudinal strie. It might well be named C. Ruthveniana, in memory of the old geological collector who laboured for very many years in the Kendal district for Professor Sedgwick and others. 18. C. oretonensis and truncata, H.W. (‘Third Report,’ pp. 21, 22), though near to C. inornata in shape, hold their distinct places as species. 19. Of C. solenoides and CO. gobiifornvis (‘Third Report,’ p. 22) there is nothing new to be stated. 20. As intimated in the ‘ Third Report,’ pp. 27, 28, the presence of the ocular tubercle has an important signification, showing that the animal must have had an organ equivalent to the eye sufficiently de- veloped to affect the external covering, whether it was adapted for clear vision or not. It may be a family distinction; at all events, the oculate carapaces have to be removed from Ceratiocaris, and we propose that M‘Coy’s C. elliptica be referred to a new genus under the name Hmmelezoe.' E. elliptica, M‘Coy, is described in the ‘Third Report,’ p. 27, as represented by the type, Cambridge Mus. 6/15; but Ludlow Mus. G., and M.P.G. X +; and 33 differ from it considerably. The first of these is shorter and broader (higher), nearly semicircular in outline, with an acute and projecting postero-dorsal angle; and its surface has a fine, almost 1 -Eupmedns, elegant; (w, life (a termination common in some of M. Barrande’s genera), ON THE FOSSIL PHYLLOPODA OF THE PALZOZOIC ROCKS. 233 silky, linear ornament. As a new species this might be known as Hi. tenuistriata. The specimen X 4), is subovate, larger than either of the -othet two, and is coarsely striate, with longitudinal anastomosing wrink- lets, and might be named H. crassistriata. M.P.G. 33 is smaller than any of the foregoing, somewhat boat-shaped, between the last and elliptica in shape, but not identical with either; and it is rather coarsely striate longitudinally. To this form we propose to give the name H. Mac- -coyiana, in honour of the first describer of any member of this genus. 21. At page 26 of the ‘Third Report,’ we described Salter’s Ceratio- caris ? ensis, and now we are still more confirmed in the opinion that it belonged to a distinct genus. Its large size, its curvature, and the serration on both the upper and the lower edge, and the profuse spination (as shown by pits) on the latter distinguish it from other telsons; and more particularly its lozenge-shaped sectional area, of an unequal rhombic form, blunter at the outer (upper) and convex edge than on the other, the ridge along the sides not being quite on the medial line, but nearer the outer than the inner edge. We propose the name Xiphocaris! for this rare genus. M. Barrande’s Ceratiocaris primula (‘Third Report,’ p. 32)-has a style {or stylet?) with lozenge- or diamond-shaped section; but this uropod, though curved, is of different dimensions, and is pitted all over. 22. Physocaris vesica, Salter (‘Third Report,’ p. 28), we consider as having had its abdominal segments shifted from below upwards, and turned over on their axis, after death; and therefore as having been figured upside down. 23. Of C. ? lata, insperata, and perornata we have no further evidence at present. 24 Ceratiocaris ? longicauda, D. Sharpe (‘ Third Report,’ p. 29), a foreign (Portuguese) form within our reach, has been studied in the Geological Society’s Museum, Burlington House, and shows some inter- esting features. Its scientific name was given under the supposition that the fossil was a Dithyrocaris, with a longer abdomen than usual; but its cylindrical ultimate segment, its somewhat bayonet-shaped style, and blade-like stylets clearly remove it from that genus, as intimated in our former notice. It is probably distinct also from Ceratiocaris ; it has some analogy with the Devonian Hlymocaris; but at present we cannot fix its generic place. 25. In the ‘Sitzungsb. K. bohm. Ges. Wiss.’ 1885, M. Ottamar Novak, Keeper of the Barrande Collection at Prague, has described a new Phyllocaridal genus from the étage F, f 2, in Bohemia, as Ptycho- caris, with two species Pt. simplex and Pt. parvula, characterised by a strong and obliquely longitudinal ridge or sharp fold on each valve, and by an anterior group of three small nodules, an ocular tubercle behind them, and some larger but less distinct swellings further back, but still ain the antero-dorsal region, M. Novak supplies also a Table of the ‘vertical distribution of the Phyllocarida in Bohemia. In the Annales XIII. Soc. Géol. du Nord, 3™° Livr. April 1886, p. . 146, M. E. Canu gives.a résumé of the results of M. O. Novak’s re- ‘searches in the Phyllocarida, with some woodcuts of Aristozoe regina, Bactropus longipes, and Ceratiocaris debilis (see ‘Third Report,’ pp. 32-34), and of Ptychocaris simplex (see above). 26. Dr. A. S. Packard, junior, has described and figured some ! Eipos, a sword; kapts, a shrimp. 234 REPORT—1886. peculiar appearances on an internal cast of a Carboniferous Phyllopodous. carapace from Illinois, as traces of four pairs of lamellate limbs (thoracic feet), probably ‘the homologues of the exopodites of Nebalia.’ He has. defined the genus and species as Cryptozoe problematica (‘ American Naturalist,’ Extra, Feb. 1886, p. 156 ; aud ‘ Proceed. Americ. Philosoph. Soe.’ vol. xxiii. No, 123, pp. 380-383). 27. In a Geological Report, Assembly Document, No. 161, 1885 (or 1886), Mr. J. M. Clarke has defiued the localities and geological succes- sion in Ontario County and New York, where the Phyllopods which he previously described (see ‘Second Report,’ 1884, pp. 80-86, and ‘ Third Report,’ p. 3) have occurred with or without Goniatites. 28. A list of the British Paleozoic Phyllocarida described in the Third and Fourth Reports. Ludlow Beds Wenlock Beds | Upper Llandovery ; Onny ; Kirkby- Lonsdale River stone ; Oreton Wenlock Upper Shale Lower Ludlow Portmadoe Ludlow Tremadoc Slates ; Lower Shale Carboniferous Lime- ock Upper Ludlow ; Upper Ludlow ; Benson Knot, Kendal | | Wenl Lower Ludlow ; at and near Ludlow Lower Wenlock; Helm Knot, Dent Dudley Upper Ludlow ; Les- mahago and Muirkirk | | | -| + | aa 1. Ceratiocaris leptodac- | — — == = tylus 2. C.Murchisoni . .| — x = | = | x & x | Knigh- x ton 3. C. gigas. . . ° . =~ 4. C. valida . - . 5. C.attenuata(tyrannus?) 6. C. canaliculata . 7. C. Halliana . 8. C. Pardoeana 9. C.ludensis . 10. C. robusta . 11. C. lata 5 12. C.angusta . 13. C.minuta . 14, C. papilio . 15. C. stygia . ie xxxXXX x xX 16. C. laxa . 17. C. Salteriana 18. C. cassia. 19. C. cassioides 20. C. compta EAA AL Ve Lee WL Sv ESSv I! e331 Tesi | effet Ha | ok Oe si Le Hebalelos exes et ales ST el il xX XX Fresh- water, Pem- broke- shire 21. C. decora 2 . 22. C. oretonensis 5 23. C. truncata . 5 24. C.inornata . . 25. C. Ruthveniana . 26. C. solenoides . . 27. C. gobiiformis . 5 28. C. perornata . ° 29. C. ? lata 5 5 . 30. C. ? insperata ° % 31. C.? sp. . 4 4 = 32. Physocaris vesica . . 33, Xiphocaris ensis . 34, Emmelezoe elliptica 35. E. tenuistriata . 36. E.crassistriata . . PSTN OU ea Ege: Hesssilialbcibell I] esses eh as ee | | x | 37. E. Maccoyiana . = —_ — x ON THE CIRCULATION OF UNDERGROUND WATERS. 235 Twelfth Report of the Committee, consisting of Professor E. HULL, Dr. H. W. Crosskey, Captain DoucLas GaLTon, Professors J. Prestwich and G. A. LEesour, and Messrs. JAMES GLAISHER,. E. B. Marten, G. H. Morton, JAMES PaRKER, W. PENGELLY,. James Puant, I. Roserts, Fox Stranaways, T. 8. STOOKE, G. J. Symons, W. TopLtey, TyLpen-WricHt, E. WETHERED, W. Wuiraker, and C. E. DE Rance (Secretary), appointed for the purpose of investigating the Circulation of Underground Waters in the Permeable Formations of England and Wales, and the Quantity and Character of the Water supplied to various Towns and Districts from these Formations. Drawn wp by C. E. DE RANcE. Your Committee have not been able to include in the present report information which would be of considerable value in drawing up a final report on the result of their thirteen years’ labour. They therefore consider they will best carry out the instructions given them in 1874 by continuing their investigations for at least a year. It had been hoped by the Committee that the details of the sections passed through, and the character and quantity of several important wells and borings now in progress in the Midland counties, might have been laid before this meeting, but they are still incomplete. Northamptonshire.—At Kingsthorpe, 24 miles north-east of North- ampton, a trial for coal was made in 1830, against the advice of Dr. William Smith, F.R.S., and Mr. Richardson, of the British Museum. This shaft was described by Dr. Buckland, and later by the late Mr. S. Sharp (‘ Geol. Mag.,’ vol. viii.). It passed through 120 feet of Oolites,. 760 feet of Lias, and 60 feet of sandstone, 12 feet of marls, and 15 feet of conglomerates, referred at the time by Dr. Smith to the New Red series.. The Middle Lias (or marlstone) appears to have produced 36,000 gallons. per hour at a depth of 210 feet from the surface, and the New Red a like quantity of brackish water from a depth of 880 feet. The work was stopped at 967 feet, after costing 30,0001. . In 1846 the London and North-Western Railway bored for water in) Northampton, and, on reaching 650 feet, tapped a salt-water spring, con- taining chloride of sodium, carbonate of soda, sulphates of magnesia and lime, the spring occurring in a 4-feet bed of magnesian limestone, lying. under 50 feet of variegated sandstone and marls. In 1879 a boring was made by the water company at Kettering Road, one mile north-east of Northampton, to a depth of 851 feet. In this: boring the Lias rested on an eroded surface of crystalline conglomerates and sandstone, 674 feet in thickness, which are somewhat doubtful in age, no fossils having been discovered, but overlie 45 feet of carboniferous- dolomitic limestone with fossils, which is believed to have yielded the 200,000 gallons of saline water met with in this boring, containing 1,200: grains of mineral salts per gallon. -The second trial of the Northampton Waterworks Company was: at Gayton, two miles north-west of Blisworth Station, and five south- west of Northampton. The details are given by Mr. H. J. Eunson (Range of the Paleozoic Rocks beneath Northampton, ‘Q. J. G. S.,” 236 REPORT—1886. vol. xl. part III. p. 485). The Lias, White Lias, and Rhetic continued to 617 feet from the surface, the latter resting on a slightly eroded series of marl, followed by variegated sandstone 60 feet in thickness, which are referred to the Trias. At 676} feet occurred carboniferous sandstone with fossils, which, with the underlying marls and limestones are regarded as a local littoral deposit, lying on the true carboniferous limestone occurring at 699 feet. The beds beneath are very remarkable, but do not affect the present inquiry. The total depth reached was 994 feet. As in the other boring, the water was saline, containing 1,500 grains of mineral salts to the gallon, the quantity being only 100,000 gallons per day. The water stood 20 feet higher than at Kettering Road, giving a gradient (*) of 33 feet per mile to the north-east. In the boring tele carried out for Mr. J. Fleming (of Newcastle-on- Tyne), at Orton, five miles west of Kettering, and twelve miles to the N.E. of Northampton, the Triassic beds were absent, and the beds of doubtful age were 24 feet, the underlying carboniferous beds were absent, and a quartz-felzite 74 feet thick still persisted when the boring was abandoned at 789 feet. Details of Wells and Borings, Cheshire. Collected by Mr. G. H. Morton, E.G.S., from Mr. H. Aston Hill, CE. 1. The Wallasey Waterworks, Great Float, near Birkenhead. 1a. No.1 well, 1861. Borehole enlarged to 13 inches, and deepened to 400 feet from surface in 1876. No. 2 well 1874; not deepened since. 2. 23 feet. 3. No. 1 shaft, 7 feet diameter, 90 feet from surface. Borehole 13” diameter, 400 feet from surface. No. 2 shaft, 7 feet diameter, 90 feet from surface. Borehole 18” diameter, 400 feet from surface. 3a. 4. The pumping is almost continuous, and the working level of water is about 40 feet from surface. After stopping four hours the water rises to 24 feet from surface. 4a. When No. 1 well was sunk in 1861, the water rose to within 9 feet of the surface. Cannot tell how high it would rise now, being unable to stop pumping for a suf- ficiently long period. 5. 1,250,000. 6. No. No. 7. No. Do not stop pumping sufficiently long to see what height water would rise to; but as a rule our working level is about 17 feet below mean level of the Birkenhead Docks. 8. Not had an analysis made recently. Water is considered of excellent quality, and does not possess any marked peculiarity. ft. ft. 9. Red marl . . i Saks} Red rock . . . 56 - Sand and marl. ‘ > 9 Grey rock . - 5 3 2 Marl . F a eG Hard red rock . : 2 22 Clay, stones, and sand .. 28 Soft red rock . 5 . 48 White rock : 5 le Total A 5 . 246ft. from surface, in 1861. 10. Probably. 11. Yes. 12. It is believed so. 13. No. 14. No. 25. Don't know of any deep wells having been discontinued; but several shallow ones have been, in consequence, no doubt, of surface contamination. Northamptonshire. Section of Boring at Hambledon. Oollected by Mr. W. Whitaker. ft. in. Inferior Oolite (Northampton sand) . J - 10 6 gees Lias . 3 - 176 O /Marlstone. rock - 3 bn Clay ° : 5 Pele mle hu, Rock . - : } Lao : : Clay : é ; ay 12 iO Middle Lias_ . mnhines : F : as tae 7 Clay S : ; 2» 6 EO Rock - . : Sobel it (G) Clay ° 5 2 - + ON THE CIRCULATION OF UNDERGROUND WATERS. 237 Boring ceased 240 feet from the surface. Water was found in the lower part of the marlstone, but not in great quantity. An increased quantity was found in each of the three bands of rock subsequently per- forated. The water-level stands in the bore about 6 feet above the bottom of the marlstone. Shropshire. Collected by Mr. T. S. Stooke, C.H. 1. At Sunderton, near Shrewsbury. ia. 1884. No. 2. 205 feet. 3. No well. Bore-hole 76 feet in depth, 5 inches diameter. 3a. 4. Normal surface of water 11 feet. 4a. 43 feet; 11 feet. 5. The full yielding power of bore-hole has not been tested. The yield is considerable. 6. Not known to vary. 7. Not known to be affected about 5 feet above an adjoining stream. 8. By Mr. Thomas Blunt, M.A. Total solid contents 5 - : . 50:00 grains to gallon Chlorine in chlorides s : é ; - 8°50 § # Nitrogen in nitrates ; e 3 : - 0:00 Oxygen absorbed . : : : . » 0012 of Temporary hardness, Clarke’s scale : "255° Permanent 5 (after boiling for some time) 93° The water is pronounced wholesome, but somewhat hard for drinking and domestic use. ft. 9. Soiland clay . r 2 . i : A c 200 Red sand . ‘ C : : : : : ol Clay with stones . 2 2 = ; é é - 20 Red sand ‘ 3 ‘ 3 : : F ane Clava % : 5 ; : - - : ° - 5 New red sandstone : : : . . : . 38 Marl . : : : 5 : ‘ 4 : . 4 Total depth . : : : - 76 9a. New red sandstone. 10. Yes. 11. Yes. 12. No. 13. No. 14. No. 15. No. 16. Collected by Mr. Thos. S. Stooke, C.H. 1. Atcham workhouse well, near Shrewsbury. Ia. A bore-hole was put down in 1884. 2. 206 feet. 3. 60 feet in depth; 4 feet in diameter; 181 feet; cased with 4-inch tubes. 3a. No driftway. &. 54 feet; the water level is only reduced about 6 inches in affording the supply required. The ordinary water level is quickly re- stored. 4a. The water stands about 12 inches higher in well since the bore-hole was put down. 5. The average quantity pumped is about 10,000 gallons daily. The full yielding power of the well and bore-hole has not been tested. 6. Water level does not vary since bore-hole was put down. 7. Not affected by localrains. About 15 feet higher than the normal summer level of Severn, which is situated about 4 mile from the site of well. 8. Water of very good quality; no recent analysis hag been taken. 9. No record of strata pierced by the well. Section of Boring. 60 to 80 feet—sand. 80 to 124 ,, —sand and gravel. 124 to 152 _,, —-coarse gravel sand with flint. 152 to 210 ,, —-grey sand and gravel. 210 to 214 ,, —red sandstone. 214 to 230 ~,, —marl. 9a. Sand and gravel beds. 10. 41. The well is cased with brickwork through- out. 12. No. 23. No. 424. No. 15. No. 16. The bore-hole was carried through 23” tubes placed within the 4” tubes to the depth of 230 feet. The inner tubes were withdrawn, as an ample supply was obtained at the depth of 181 feet. 238 REPORT—1886. Collected by Mr. CO. E. De Rance from Mr. William Blackshaw, Borough Surveyor, Stafford. Stafford Corporation Waterworks Pumping Shaft and Trial Boring at Ensonmoor. Particulars of Strata passed through. ft. in. 1 0 Soil. 16 6 Clay. 7 6 Loamy sand. 14 © Gravel yielding 400,000 gallons of water per 24 hours. 35 O Red marl. 4 0 Sand. 0 9 Light friable sandstone. 46 7 Blue and red rock marl with veins of gypsum yielding 800,000 gallons of water per 24 hours. 356 0 Blue and red rock marl with veins of gypsum but no water. 369 © Red and grey sandstone. 850 4 June 3, 1886.—Water overflowing at the rate of 44,000 gallons per 24 hours. South Staffordshire-—In districts of Old Hill and Tipton many of the coal mines are waterlogged, and are underwatered by a pumping commission, appointed in 1873, with powers to levy rates of 9d. per ton on coal, iron- stone, and slack, and 3d. a ton on fireclay and limestone. In Tipton in 1873 there were 77 pumping stations ; in 1885 these were reduced to 10. The principal pumping stations over an area of 50 square miles are Bradley Station (near Moxley, G. W. R.), which can raise four million gallons from a depth of 126 yards, the Moat, and the Stoneheath Stations. APPENDIX I. Memoranda for Mr. De Rance, Reporter to the Underground Water Com- mittee of the British Association, Birmingham Meeting, 1886. By Mr. E. B. Marren, of Pedmore, Stourbridge. The Committee have investigated chiefly the Triassic Rocks, and with a view to trace the flow of potable water, with a few illustrations from other geological formations. The drainage of the South Staffordshire and Hast Worcestershire coalfield being taken up by a commission under the South Staffordshire Mines Drainage Act, 1873, information has been obtained of the state of the underground water, and many a puzzle has presented itself as to how far the effects of any one pumping station will reach, as it depended not only on thenatural porosity of the strata, but also on the extent to which the natural barriers had been pierced or weakened by mining operations. It was found that although naturally the underground water would level itself and flow out at the nearest surface stream, as if all the coal- fields were one homogeneous rock, it was far from the case when attempts were made to pump the whole sufficiently for mining purposes. It was then found that the part dealt with by the Act divided itself into the two sides east and west of the Sedgley, Dudley, and Rowley Hills; and the east side again into four smaller areas, Bentley, Bilston, Tipton, and Old- bury; and in the west Kingsaricford and Old Hill, any one of which could be pumped separately. These smaller districts were again divided into smaller pounds, each separated when the water was pumped down below the broken barriers. ON THE CIRCULATION OF UNDERGROUND WATERS. 239 These are readily seen in the sketch map of ‘area under the Act with five large districts, each having the smaller pound-boundaries marked in different colours. It was soon found that Bilston and Tipton were so far one that when Tipton was pumped Bilston water flowed down and nearly swamped Tipton, so that some of the largest pumps in the kingdom have been put down on the lower side of the boundary between those districts, and the most difficult operation in mining successfully carried out, of driving under the Bilston water and tapping it. To each pumping station the water flows, but the district which it will drain depends on the ‘ faults’ and workings. A few examples may be of interest, especially as compared with the behaviour of the water in the more homogeneous strata under the inves- tigation of the Committee, and will be given in the next report. Apprnpix IT. By Mr. E. B. Marten. Although the records are, I believe, closed, I send you particulars of four springs yielding extremely good water and sufficient for supplying the village of Pedmore, just upon the borders of the great western boundary fault of the coalfield as it passes away south under the Clent Hills and Hagley. Wychbury Camp Hill, like Clent, Walton, Woodbury, and other hills of Permian formation, is capped by the Breccia described by Professor Jukes, which receives the rainfall and holds it like a sponge on the some- what denser rock below, springs showing themselves all around 500 feet above sea-level at the base of the Breccia at Pedmore and Hagley, and forming the heads of rivulets. Within the last few weeks the water has been analysed by Dr. Bostock fill, and found to be very good as follows :—Parts per 100,000: total solid impurity, 20°0; organic ammonia, 0-002; free ammonia, 0:001; chlorine, 2°5 ; temporary hardness, 5°43; permanent hardness, 9°57 : total hardness, 15°U0. On the west side of the fault the New Red sandstones abut against the Permian, and being far more porous = the rainfall sinks away, so that at Hagley ae the few wells are 70 feet deep, and at 3 Pedmore there are no deep wells, and the few that are shallow easily get contami- Stourbridge ? nated. The general level of the water in the New Red sandstone is about 250 feet COAL above the sea, the river Stour being the Asa apy lowest outlet about one mile below the Wollaston Pumping Station, described by me on page 7, 1882 (Eighth Report), is | \ fssedcia about oho feet above sea-level. Fi as ‘ane In excavating for a small reservoir, ty 40) about three years ago, one side slipped oy Pp in, the whole coming off like half a peg- NEW RED SANDSTONE = top, point downwards, leaving a smooth, = polished, ‘slickenside’ surface, so that ES we were evidently exactly on the great % = western boundary fault. 240 REPORT— 1886. Apprenpix III. Weekly Readings of Height of Water in Messrs. S. Courtauld § Oo.’s Well, Bocking, Essex. Datum is-137:07 Feet above Sea-level. Above Above Above Date Datum in Date Datum in Date Datum in Inches Inches Inches | Aug. a 1883 }* iy Aug. a ; 38 Sept. 8 ,, 142 anea 36 2) 30 im ORE ea 352 ” ” ” 35 ares! aaa TS, 11 urvule 372 | Oct... “A\rs3 123 te 35° A Oilers, 8 Eee 36 BR Oiplip: Bs 123 Oct 36 bee) eee = | ” ” ’ 38 Nove 5: 5 12% ese 35 Pres 121, 124 Nov 41 Mat LD’ o 45; lly lw 35 ” 26 ” 16 ” 17 32 WMeeroe abs 12 ieee 31 LO) vey 11 Dec 34 ” ee 10 ” 34 ” Fl ” x ” a 30 | ” ” 9 ” 29 | Jan. 7, 1884 12 4128 31 ee, 0 eee 93 Jan. 83 Pas. leh: wy, 94 Ae 33 ” 28 ” 163 ” 33 Feb. 4 ,, 11 . 26 372 i aaiatt,, 15 Feb 36 ” 18 ” 13 ” 37 ST SOUP kas, 133 ” 35 Nar aio ss 13 ”» 324 | ” as ” ae Mar 30 joureainds Ldn hess 3 1 15, s a pilates 144 ” 31 (Avorn sass 15 ” a2 5 i is 125 April 7 34 ” ’ ” 33 a ce 313 é 322 May 5 ,, 42 ” 33h ” 2 ” 44 May 33h 53 TE) oe 49 ” 294 1 Gy 203 9%; 49 - 31h June 3 °° 57 ” 32 seal ee SA (ig 32 5 eelOe ” 31 jumeaone 57 ” 31 SS BO iss 58 ” 314 July 7 ” 583° ” 29 a 47%, ness July 271 ” ae ” ae ” aa » ” ” Awe. 5 ,, 54 ” 29 > Essex earthquake, April 22, 1884. ? Highest recorded since earthquake. 2 Lowest recorded since earthquake. ON THE CIRCULATION OF UNDERGROUND WATERS. 241 Apprenpix IV. List of Questions Circulated. 1. Position of well or shafts with which you are acquainted ? 1a. State date at which the well or shaft was originally sunk. Has it been deepened since by sinking or boring? and when? 2. Approximate height of the surface of the ground above Ordnance Datum (mean sea-level)? 3. Depth from surface to bottom of shaft or well, with diameter. Depth from surface to bottom of bore- hole, with diameter ? 3a. Depth from the surface to the hori- zontal drift-ways, if any? What is their length and number? 4. Height below the surface, at which water stands before and after pump- ing. Number of hours elapsing before ordinary level is restored after pumping ? 4a. Height below the surface, at which the water stood when the well was first sunk, and height at which it stands now when not pumped ? 5. Quantity capable of being pumped in gallons per day of 24 hours? Average quantity daily pumped ? 6. Does the water level vary at different seasons of the year, and to what extent ? Has it diminished during the last ten years? 7. Is the ordinary water level ever affected by local rains, and, if so, in how short a time? And how does it stand in regard to the level of the water in the neighbouring streams, or sea ? | 8. Analysis of the water, if any. Does the water possess any marked peculiarity ? 9. Section with nature of the rock passed through, including cover of Drift, if any, with thickness? 9a. In which of the above rocks were springs of water intercepted ? 10. Does the cover of Drift over the rock contain swrface springs? 11. If so, are these land springs kept entirely out of the well? 12. Are any large faults known to exist close to the well? 13. Were any brine springs passed through in making the well? 14. Are there any salt springs in the neighbourhood ? 15. Have any wells or borings been dis- continued in your neighbourhood in consequence of the water being more or less brackish? If so, please give section in reply to query No. 9. 16. Kindly give any further information you can. Second Report of the Committee, consisting of Mr. W. T Bianrorp, Professor J. W. Jupp, and Messrs. W. Carrutuers, H. Woop- warp, and J. S. Garpner (Secretary), appointed for the purpose of reporting on the Fossil Plants of the Tertiary and Secondary Beds of the United Kingdom. [PuaAtTe VII.] Ovr attention has been devoted exclusively this year to the fossil flower- ing or phanerogamous plants. The results of our researches point to the conclusion that while that section known as Gymnospermous, to which the Conifer belong, is of the highest antiquity, being almost coeval with the first definite remains of plants in the Palzozoic age, there are no Angiospermous plants in British rocks of greater antiquity than the Secondary period, if we except the problematic plant known as Spirangiwm. Even down to so late as the Lias we have been unable to ascertain that any indisputable Angio- sperm has been discovered within our area, for we are led to the conclu- sion ve the supposed Monocotyledons from the Rhetics, near Bristol, : R 242 REPORT— 1886. hitherto referred to the family of Pond-weeds under the name Najadita, are really cryptogamic plants of the moss tribe, closely allied to the river moss Fontinalis. This group had not previously been found fossil, and, so far as it goes, would indicate rather a temperate climate. It is important to notice that these conclusions are shared by such high authorities on fossil plants as Prof. Williamson, Mr. Carruthers, and all botanists who have examined them, as well as by Mr. Brodie, the possessor of the spe- cimens. The Lilia, Bensonia, and other supposed Monocotyledons of similar age are very imperfectly preserved, and doubtless referable to Cycads, a family which then abounded. We have examined a large number of specimens of the anomalous Jurassic plant described by Carruthers as Williamsonia. It is well known that Prof. Williamson, in whose possession or charge a number of the finest specimens remain, has devoted a considerable amount of attention to them, without, however, feeling justified in coming to any very definite conclusion as to their true position in the vegetable world. De Saporta, on the other hand, has found more perfectly preserved specimens in France, and has no hesitation whatever in referring them to the group of Pandanacee. Though there are still many difficulties in the way, our own examination of the specimens in London, Manchester, Cambridge, and elsewhere tends to confirm Saporta’s view so far as that there do appear to be vestiges, in some cases at least, of lignitic structure which may represent the areole or carpels. These rather minute cavities and the lignitic matter surrounding them fall away on exposure to the air, and only traces of them are visible. Should Saporta’s contention be upheld, Williamsonia will be by far the most perfectly known of the secondary Angiosperms, since all the organs of fructification and even of foliation are more or less known. A still more definite Monocotyledon is the Podocarya, from the Inferior Oolite, originally figured by Buckland, and redescribed by Carruthers. Its resemblance to the fruit of Williamsonia, as interpreted by Saporta, is extremely striking, and on suggesting this to that author, he replied that he was in the act of preparing an important work on the very subject. The same work is to include an illustration of the most recent member of the group, obtained from the Grey Chalk of Dover, and which we thought advisable to communicate to him. Next in point of age, among English Monocotyledons, to the Podo- carya is the Kaidacarpum, from the Great Oolite, also described by Car- ruthers, and by him referred to the Pandanee. We have been able to ascertain that a second species, hitherto supposed to be of Cretaceous age from the Potton Sands, is a derived fossil, and undoubtedly Jurassic. A third species was originally figured, without any reference in the letter- press as to its age or locality, by Lindley and Hutton as Strobilites Buck- landi, in their ‘ Fossil Flora,’ vol. ii. pl. 129, published between 1833-35, from a drawing made by Miss E. Bennett for Dr. Buckland. In the first edition of Morris’s ‘ Catalogue,’ 1843, it is set down as from ‘ Gr. S. Wilts,’ which cannot mean either Lower or Upper Greensand, the abbre- viations for which are ‘L. G. 8S.’ and ‘U.G. &.,’ but which certainly looks like a misprint for ‘ Gr. O.,’ the sign for Great Oolite. In the second edition of Morris, 1854, the locality is corrected to ‘U. G. S. Wiltshire,’ but it appears likely that the correction may have been made withont ascertaining the facts de novo, for the only entry occurring in Miss Ben- nett’s ‘Catalogue of the Organic Remains of Wiltshire,’ published in ON THE FOSSIL PLANTS OF THE TERTIARY AND SECONDARY BEDS. 243 1831, that could possibly refer to this fossil, is a ‘ Cycadeoidea ?’ from the Portland Beds, which occurs under the heading ‘ Woods’ on p.9. A journey to Newcastle with the object of examining the Hutton collection of fossil plants, where it seemed probable the specimen might be found, has been unsuccessful, and its present whereabouts is still unknown. We think it, however, far more likely to prove a Jurassic than a Cretaceous fossil if found, and the genus should not be included in lists of plants of the latter age. The oldest Monocotyledons thus appear to be referable to the Panda- nex, a group of plants distributed in widely distant and remote oceanic islands, and whose fruits are still met with at sea in drifts of vegetable matter. Next to these in antiquity are two very monocotyledonous-lookin fragments from the Jurassic of Yorkshire, which have been fully described in the ‘ Geological Magazine’ for May and August. The one is apparently an unopened palm-like spathe, and the other a jointed cane-like stem. Mr. Brodie possesses an undoubtedly monocotyledonous leaf fragment from the Purbeck of Swindon. The Aroidee have long been supposed to be a group of very high antiquity, but there are good reasons for believing that the supposed remains of aroideous plants from beneath the Tertiaries are, without exception, referable to other groups, and actually there are no known traces of them earlier than the Middle Eocene, when they become by no means uncommon, In a similar manner the fruits once supposed to represent palms in the Paleozoic and Mesozoic rocks have been gradually removed or suppressed, and, unless the fragments of palm-like wood in the gault at Folkestone are taken into account, there are no traces of palms in any of our Secondary strata. They, however, appear as low down in our Eocene as the Woolwich series. We are not yet able to speak with certainty regarding the supposed liliaceous or Dracena-like stems from the Wealden, so frequently men- tioned by Mantell, and now in the British Museum, since they have not yet been thoroughly examined ; but it is very probable that they are liliaceous, and, if so, of the highest interest. The Wealden has so far yielded no other trace of any more highly organised plants than ferns and Gymnosperms, and this, when we remember that Monocotyledons were undoubtedly in existence, is a fact that should be of great signifi- cance to speculative geologists. The sediments must represent the deposits of the drainage system of a large area, for they are of vast extent and thickness, varied in character, and abounding in remains of trunks and stems, fruits and foliage of plants. In them, therefore, if anywhere, we might reasonably expect to find at least the traces of reed and rush, but the swamps seem to have been tenanted only by Equisetum and ferns, and the forests mainly by Cycads and Conifers. The same absence of Angiosperms, so far as British rocks are concerned, is continuous throughout the Neocomian and Gault, and it is only in the White Chalk that we meet with any indications of them, and these only take the form of a more than suspicious impression of a net-veined leaf, in the Jermyn Street Museum, and of some structureless bodies which were apparently some kind of fruit. When, however, we turn to the gymnospermous section of Phanero- gams the records are very different. To refer here to the earlier Secondary R2 244 REPORT—1886. Coniferze and Cycadez would be quite beyond our province, and it is only those of the Cretaceous, as the last discoverable ancestors in our area of the Eocene flora, that are of immediate interest. These belong, excluding Cycads, chiefly to the newest section of the Coniferx, the Pine family. We are able to make the following contribution to our knowledge of these :— Pinites Andrei, Coemans. ‘Flore fossile du Terrain Crétacé du Hainault,’ 1866, p. 13, pl. v. fig. 1. Gault, Folkestone, fig. 1. This specimen measures 5 centimetres in length and nearly 3c. in breadth, though something should be perhaps deducted for the compres- sion undergone. When perfect it was probably composed of 50 to 60 imbricated leathery scales, about half that number being visible on the exposed face. The substance of the scale seems to have been consider- able, though the edges are thin; they are smooth even without striz, and with the upper margin round to obtusely pointed. They are apparently variable in size. The cone is of the same general type as P. Andrei, Coem., from the Gault of La Louviére, Hainault, though somewhat shorter, more oval, and with thinner and rounder scales. The form and general consistence of the scales, as well as their size, the number composing each whorl, and their disposition are, however, so similar that we think it better, in the case of so imperfect a specimen, to unite it rather than claim specific rank on account of distinctions that might largely disappear with more perfect specimens. If the assimilation is correct the apex of the cone, as well as the base, would have been somewhat pointed. The cones are very abundant at La Louviere, more than 100 specimens having been collected ; and they are stated to have been frequently curved and highly resinous. The specimen from Folkestone was found by us, being unique from that locality, and is now in the British Museum. Pinites Valdensis, sp. nov. figs. 4 and 5. Wealden, Brook Point, Isle of Wight. This fragment shows the presence in the Wealden flora of a Pine of the section Strobus with a cone composed of scales as numerous and thin as in any recent species. The cone was long, cylindrical, and tapering, the scales very numerous, permanent, imbricated, leathery, pointed, and lightly thickened at the apex, with entire margin, striated, and slightly keeled. It somewhat resembles P. Dunkeri, Carr., also of the Wealden, but is probably a distinct species. The specimen, fig. 5, is from the York Museum, and 4, in which all the scales are mutilated, from the Woodwardian Museum. Both these, with several others, are from the Wealden of Brook, so that it appears to be by no means rare there. It is associated with Cycadostrobus elegans, Carr.,' a representation of which is given for comparison in fig. 8. Pinites Carruthersi, sp. nov. Fig. 6. Wealden, Brook Point, Isle of Wight. The fragment figured represents another long cylindrical cone with very numerous persistent leathery imbricated scales. It tapers like the one last described towards the base, the scales being much thicker, though thin at the edge, smooth, without keel, and with entire rounded margins. It resembles the Gault species P. Andrei in texture, but there were at least twice as many scales in each whorl, and these are much more imbricated. It also is quite distinct from P. Dunkeri, Carr. 1 Journ. of Bot. vol. iv. pl. lvii. fig. 9. ON THE FOSSIL PLANTS OF THE TERTIARY AND SECONDARY BEDS. 245 It resembles Cedrus Lennieri, ‘Sap. Veg. foss. de la Craie inférieure des Environs du Havre,’ Mém. de la Soc. Géol. de Normandie, 1877, but is not apparently the same species. Pinites cylindroides, sp. nov. Lower Greensand, Potton. Figs. 2 and 2a. This is an almost perfectly cylindrical specimen, being very slightly thickened towards the base, 7 centimetres in length and 22 millim. in diame- ter, composed of about 96 scales, arranged in 12 rows from left to right, and 8 rows-from right to left, the arrangement thus being ,8,._ The scales are sbort and at right angles to the axis, with a smooth flat half-moon-shaped apophysis or scale-head, now gaping, but evidently imbricated before the seeds were shed. The scales become very small towards the base. The summit is abraded, exposing the end of a somewhat slender axis, fig. 2a. Certain grooved lines on the sandy matrix between the scales show that the cone was furnished with foliaceous bracts, and the marks of a boring insect are visible. The specimen, which is quite distinct from any other fossil or recent cone, is singularly elongated and cylindrical, scarcely tapering at all from the base upward. It is fortunately in excellent con- dition, certainly not derived from any older bed, like so many of the Potton fossils, and is well cared for in the Woodwardian Museum. Pinites Pottoniensis, sp. nov. Fig. 3. Lower Greensand, Potton. The fragment figured, though much mutilated, fortunately shows the characteristically winged seeds of Pinus in the most perfect manner, entirely removing any lingering doubt as to the occurrence of represen- tatives of true Pinus as low down as the Neocomian. The scales were set at an acute angle with slightly thickened recurved apophyses, the form of which cannot clearly be made out, though they appear to have been narrow, keeled, and mucronate. It nearly resembles a'type very common in the Eocene, and is of great interest in many ways. It also is in the Woodwardian Museum, and was obtained from the same formation. The specimen, fig. 7, evidently represents a third species from the Wealden of Brook, with scales very closely resembling a common Barton and Bracklesham type, but its fragmentary condition scarcely renders it advisable to attach any specific name to it. The accompanying list comprises all the British Cretaceous Coniferse previously known, up to the present date, though there is no doubt that many new and undescribed forms must exist in collections. List of British Cretaceous Coniferce previously described. Pinites Fittoni, Carr., Purbeck, ‘A Cone,’ Fitton, ‘Geol. Trans.’ 2nd ser. vol. iv. p. 230, pl. xxii. fig. 9. Dammarites, ‘Ung. G. et spec. Plant. foss.’ p. 384. Pinites, ‘Geol. Mag.’ vol. iii. p. 543. P. Mantellii, Carr., ‘Geol. I. of W.’ 2nd ed. p. 452, 3rd ed. p. 337, pl. xlii.; and Carr. ‘Gym. Fruits,’ ‘Geol. Mag.’ vol. iii. p. 543, pl. xxi. fig. 3, Tilgate. : P. patens, Carr. id. p. 543, pl. xxi. fig. 4, Tilgate. P. Dunkeri, Carr. id. p. 542, pl. xxi. figs. 1,2, Brook. Abietites, Mant. * Geol. I. of Wight,’ 2nd ed. p. 542. P. Sussexsiensis, Carr. Zamia, Mant. ‘Quart. Journ. Geol. Soc.’ vol. ii. p- ol, pl. ii. fig. 1; Zamites, Morris Cat.; Zamiostrobus, Goepp. ‘ Ueber Schless. Gesellsch.’ 1844, p. 129; Pinites, Carr. ‘Geol. Mag.’ vol. iii. p. 541, pl. xx. figs. 5, 6. 246 REPORT—1886. P. elongatus, Endl. ‘Synop. Conif.’ p. 286; Strobilites, Lind. and Hutton, ‘ Foss. Flora,’ vol. ii. p. 23, pl. xxix. P. Leckenbyi, Carr. Pinites, ‘Geol. Mag.’ vol. vi. p. 2, pl. i. figs. 1-5, Shanklin. Abietites Benstedi, Goepp. Abies, Mant. ‘Quart. Journ. Geol. Soc.’ vol. ii. p. 51, pl. ii. fig. 2, 1846. Pinites, Carr. ‘Journ. Bot.’ Jan. 1867 ; ‘Geol. Mag.’ vol. iii. p. 541; Abietites, Goepp. ‘ Foss. Conif.’ p. 207. A. oblongus, Goepp. Abies oblonga, Lind. and Hutt. vol. ii. p. 155, pl. exxxvii. Supposed to be from Greensand, near Lyme Regis; described by a misprint as from ‘ Dresent,’ instead of ‘present’ shore. Elate, Unger, ‘Syn.’ p. 199. Abietites, Goepp. ‘ Foss. Conif.’ p. 207. Pinites, Endl. ‘Synop. Conif.’ p. 283; Carr. ‘Geol. Mag.’ vol. iii. p. 541. (Professor Williamson is describing a magnificent specimen of this or an allied form.) Pinites gracilis, Carr. Gault, Folkestone, ‘Geol. Mag.’ vol. vi. p. 2, pl. i. fig. 9. P. hezagonus, Carr. id.' vol. viii. p. 540, pl. xv. Sequotites Gardneri, Carr. id. vol. vi. p. 2, pl. i. Sequovites ovalis, Carr. id. vol. viii. p. 542. Sequotites Woodwardii, Carr. id. vol. iii. p. 544, pl. xxi. figs. 11-16, Blackdown. We have now dealt with the more highly organised of our Mesozoic plants, and pass on to those of the Eocene. Among the most inter- esting of recent discoveries is that of plant-remains in a small sand-pit at Colden Common, between Bishop- stoke and Winchester, the first locality in the Hamp-~ shire basin that has yielded any of Woolwich and Read- ing age. This was first communicated to us by Mr. Whitaker, who thought the leaves might prove to be of London Clay age. They are, in fact, actually included Fic. 1.—Section at Colden Common, near Winchester. ¢ ‘ y, sie ley Geen Gt ee in its basement bed, and eet ).—a. ery sandy clay, m . ° and pale pS Rie eae et ge Oe mingled with casts of Reading Beds (5 feet).—b. Very plastic clay, of pale drab marine shells and sharks’ colour. c. Ferruginous sand with sea shells,* occasional peb- bles, enclosing rolled fragments of pale drab clay with fossil teeth, but the blocks of leaves. d. Imperfectly sean grey loamy sand, clay with leaves are derived, though other unfossiliferous clay-seams are in situ. If not of London Clay age, however, they are much nearer to it than the Reading flora, d = 1 Far larger specimens than that originally described, one 8 inches long by 13 inch in diameter, have since been found. 2 Cardium Laytoni, Panopea, Cytherea, Pecten, Thracia? Trigonocelia, Natica ? Sharks’ teeth. ON THE FOSSIL PLANTS OF THE TERTIARY AND SECONDARY BEDS, 247 which occurs below the great mass of mottled clay, whilst these lie above it as shown in the accompanying sections. . The plants show in the main, as might be anticipated, an approac Fic. 2._Section at Katgsgrove, Reading. London Clay.—a. Unctuous laminated clay, whitish, slightly mottled orange with well-defined base. There is only about 3 feet exposed here, but it becomes very fossiliferous nearer Reading, containing Ostrea, Pectunculus, Cytherea, Natica, Voluta, &c. Reading Beds.—b. Stiff clay, mottled slate and chocolate colours, 3 feet. c. The same with the addition of crimson, 10 feet. d. Dark greenish- grey clay, about 8 inches. e. Stiff clay, mottled bright pink and drab, 1 foot 6 inches. 7. Same asd, 24 inches. g. Ditto of dark crimson colour, about 18 inches. h. Yellow and drab mottled clay with traces of red, 3 feet. 7. Clayey sand, warm grey colour, about 9 inches. 7. Ditto, of greenish yellow passing into buff sand, becoming mottled greenish at base, about 4 feet exposed. The leaf bed is a little below this. h to the Alum Bay flora, which is still higher and above the London Clay; but whether these leaves are connected in any closer degree with the fruits of Sheppey than are those from Woolwich, Croy- don, or Bromley is a question which we have not as yet the data | 10° CHALK BORED BY ANIMALS Fic, 3.—Section at Coley Hill, Reading, Reading Beds.—a. Mottled clay. 6. Current- bedded sand, white to buff, with occasional galls and lenticular patches of clay, in some of which indistinct willow-like leaves occur. Thanet Beds.—c. Clayey sand, greenish in colour, with layer of irony concretions, 4 feet. d, Dark slate-coloured clay, piped with ochreous sand, 1 foot 7inches. e. The oyster bed, at first stiff dark clay with strong line of oysters, and sub- angular pebbles, then the same clay with bore- holes of green sand, becoming sandy at base with green-coated flints. for answering. There are, at all events, no remains of Palms among them, and this, so far as it goes, is against the connection; but on the 1 This in places is dovetailed into the sand, which sometimes thins considerably, though the mottled clay never rests directly on the Thanet beds. 248 REPORT— 1886. other hand the fruits of an Alnus, like that from Swale Cliff, abound. There is no large variety among the leaves, the majority being large and simple, but with highly serrate margins, and the species will not be found to exceed 12 or 14 in number, including Platanus, which is rare. Though we have continued to collect the Reading, we have been unable so far to determine any new species. The assemblage of fruits at Sheppey on the other hand becomes of increasing interest, and has proved unex- pectedly rich in Palms, many of them apparently identical with existing species which are now found growing in the remotest regions. Besides the large variety of Nipas, which are still met with in enor- mous abundance among the seed-vessels of the New Guinea drift, we have seeds indistinguishable from Verschaffeltia splendida, endemic to the Seychelles, from Sabal Blackburniana of the Bermudas, from a Desmoncus, an Areca, a Monodora, and probably of many, certainly of some other Palms. When we consider that probably many of the kinds of Palm fruits would sink at once, we realise how great an assemblage of this magnificent family is indicated by the Sheppey drift. The difficulties we fear of determining anything but a fraction of the Sheppey fruits must prove insurmountable. Their outer coats are for the most part destroyed, and some part of their inner structure, nearly always quite different in form from that which is external, is revealed. Botanists have been able to determine but few of the drifted fruits brought home by the Challenger, though these are more perfect and of living species be- longing to definite and known floras. The Bournemonth cliffs continue to furnish fresh forms, though the leaf-beds are becoming more and more difficult of access. We have especially enriched the series of Smilacee, and a complete account of them has been presented to the Linnean Society. The series now obtained falls little short of a hundred specimens, and is by far the richest of fossil Smilacez, perhaps of any family, ever brought together. Sucha material has enabled us to reduce the number of distinct species to no more than five, most of which are represented by foliage in all stages of development, from the largest leaves measuring several inches, down to quite minute leaves from near the extreme growing points. The necessity for such ex- tensive series when dealing with fossil leaves may not at once be apparent, but the President of the Linnean Society expressed the opinion at the meeting that out of less material not five but five-and-twenty species might have been made. The leaves of Smilacew are highly characteristic, and can be de- termined with a large degree of certainty ; but it is quite improbable that such will be the case with very many of the families of Dicotyledons. There is indeed little hope that more than a very few can be determined with anything like the precision required for botanical purposes, unless we can call in aid the fruits or some other organs. Thus if we may base a con- clusion upon the large number of the characteristic bracts, which envelope the seed in a section of Flemingia that are met with in the Bournemouth flora, the leaves of that genus should be far from uncommon, and they should also be found in the Swiss Oligocene, yet no species of Flemingia has ever been recorded from the Tertiaries. The leaves, however, may perhaps be sought for among the species of Populus and Carpinus. Fortunately fruits and even flowers are comparatively abundant at Bournemouth, and we consequently anticipate little difficulty in determin- ing leaves belonging to such easily distinguishable fruits as Alnus, Tilia, ON THE FOSSIL PLANTS OF THE TERTIARY AND SECONDARY BEDS. 249 Acer, Oarpinus, the Leguminose, and many others, but the residuum with indeterminable fruits, or fruits that will not float, may be very large. We are thus brought to the question, whether any value beyond that of mere landmarks, or aids to the correlation of rocks, can be attached to the de- terminations of fossil dicotyledonous leaves arrived at when fruits are absent. Nearly every Tertiary and even many Cretaceous floras are said to comprise Quercus, Fagus, and Corylus, to select these as typical examples. Now, we very much doubt whether the fruits of these genera have been met with in any strata older than the Upper Miocene, we might almost say the Pliocene; whilst in the latter the fruits of at least two of them are very far from uncommon. Fossil hazel-nuts are well known to abound in forest beds such as the one at Brook, in the Isle of Wight, and at Carrick- fergus. It does appear to us that it would have been wiser and more consistent, when arriving at these determinations, to have taken the absence of fruits into account, when these were such as would naturally have been preserved. The large proportion of fossil dicotyledonous leaves that have been referred without any hesitation to living genera must strike everyone, in comparison with the relatively few associated fruits that have been determined otherwise than as Carpolithes—a name which is a confession of failure. It will thus be seen that in our opinion the fossil Dicotyledons of our own Eocene must be dealt with in a manner different from that pursued by the majority of foreign writers on Bee subjects, and that a revision of much of their work is urgently needed. To resume our immediate subject, we have nothing new to record of the Bracklesham flora except that Mr. Elwes, in excavating in the New Forest, met with Nipadites in some abundance, and a specimen he still has proves the species to be the same as that from Bracklesham Bay, and entirely different from that which forms a conspicuous zone in the marine series of the Bournemouth group. At Barton, on the other hand, we have been able to procure nearly a dozen pine-cones, hitherto a great desideratum, from the Highcliff beds, which go far to prove that there is only one variety there, indistinguish- able from the Pinus Dixoni of Bracklesham. Along with these we have branches of apparently the Bournemouth Araucaria, and an important and entirely new fruit, fortunately represented by many specimens, which permit us to examine the details of their structure. These consist of twigs on which are seated in some profusion clusters of numerous sessile woody pericarps with deeply laciniate margin, giving the fruit when closed the appearance of a large burr. These enclose a nut or seed, rather smaller, but otherwise resembling that of a cucumber. There has not yet been time to make the researches necessary to come to a conclusion regarding it, and Mr. Carruthers and other botanists who have seen the specimens are unable offhand to pronounce upon its affinities. A rather large fossil plant from the same locality has recently been lent us by the Council of the Hartley Institute, and altogether the plants from this horizon, hitherto very meagrely represented, bid fair to take an important position. On the other hand, the Hordwell end of the same section, though twice visited since our last report, has furnished nothing new. We have fortunately met with a few very distinctly marked leaves from the Middle Headon of Headon Hill, preserved in the York Museum, which with those previously obtained from the Lower Headon of Hord- 250 REPORT—1886. well, help to bridge over one of the few gaps in our really surprisingly complete succession of Kocene floras. We have continued to investigate the great series of plant remains so assiduously collected by Mr. A’Court Smith, and with this object have visited Gurnet Bay, as well as receiving several packages of fossils from that place. While lamenting that they are of so fragmentary a nature, we cannot overlook their importance as almost the last representatives of the great series of floras which maintained themselves in our area throughout the Eocene time. As an illustration of their value we may instance the fact that while anything like true grasses seem to be wholly wanting in the pre- vious floras, there are many more or less definite indications of them in this. We have reason to hope that renewed working in the still younger beds of Hempstead may lead to further discoveries, for, besides the better. known plants described by Heer, pine-cones and a fine aroideous fruit have been obtained from them. EXPLANATION OF PLATE. 1. Pinites Andr@i, Coemans, from the Gault, Folkestone (British Museum). 2. P. cylindroides, sp. nov., from the Lower Greensand, Potton (Woodwardian Museum). 2a. End of axis, with scales of same. 3. P. Pottoniensis, sp. nov., from the same (Woodwardian Museum). 4. P. Valdensis, sp. nov., from the Wealden of Brook Point (Woodwardian Museum). 5. Another specimen (York Museum). 6. P. Carruthersi, sp. nov., from the Wealden of Brook Point (Woodwardian Museum). 7. Pinites, from the Wealden of Brook Point (Woodwardian Museum). 8. Cycadostrobus elegans, Carr., from the Wealden of Brook Point (Woodwardian Museum). The figures are about two-thirds the natural size. Report of the Committee, consisting of Professor MCKENDRICK, Professor CLELAND, and Dr. McGREGoR-Rogertson (Secretary), appointed for the purpose of investigating the Mechanism of the Secretion of Urine. Your Committee have to report as follows :—A method of procedure, and various points to be determined as to the proportion of the several con- stituents of the urine in different states of the kidney and under the in- fluence of drugs, have been decided on, and the microscopical examination of the kidney after certain experiments has been undertaken; but the progress of the investigation was hindered by unavoidable circumstances. . Your Committee therefore respectfully request to be reappointed. ap Report Brit. Assoc LSS6. Plate VII British Getaceous Cones . | BE: ta ~ _—— = \ . L Iustrating the Second Report on the Foss Plants of the Tertiary andi Secondary Beds of the Unrated Kingdorv. ON THE MARINE BIOLOGICAL STATION AT GRANTON, SCOTLAND. 25E Report of the Committee, consisting of Professor McKenpricx, Pro— fessor StrutHERS, Professor Youne, Professor McIntosu, Professor ALLEYNE Nicwoxson, Professor Cossar Ewart, and Mr. Joun Morray (Secretary), appointed for the purpose of promoting the establishment of a Marine Biological Station at Granton, Scotland. Tur Committee report that the sum of 75/. placed at their disposal has been used to aid in defraying the expenses of carrying on the work of the Scottish Marine Station at Granton. Two reports on the work of the institution during the past year are given below; they have been sent in to the Secre- tary by Mr. J. T. Cunningham, the Superintendent, who has charge ot the zoological investigations; and Dr. Hugh Robert Mill, who is respon- sible for the physical work :— The Biological work of the Station falls into three principal divisions - (1) Embryology and Morphology, (2) Faunology, (3) the accommodation of students and investigators. (1) Efforts to elucidate some facts bearing on the reproduction and development of Myxine formed the principal part of the work under this head during the autumn and winter. In the summer the aquarium had been arranged, and a large tank was specially devoted to the purpose of keeping specimens of the animal in confinement. After careful attention to the matter it was found that the creatures refused entirely to feed while in captivity ; they lived several months, but no signs of reproduc-- tive activity appeared, with one exception noted below. It was then determined to continue the examination of large numbers of specimens every month in the year in order to find if the ova were shed at any limited season. As almost nothing accurate was known on the whole subject, the first problem was to obtain ripe males and females. In No- vember the testis in its immature condition was recognised, and it was sub- sequently found that with few exceptions all very immature specimens were hermaphrodite, containing immature testicular tissue at the posterior end of the generative organ. Microscopic examination of the largest ova obtained showed that the well-known polar threads belonged to the vitel- line membrane, and were developed in tubular depressions of the follicular epithelium. In December, January, February, and March females were obtained which had just discharged their ova, the collapsed capsules, still quite large, being present in the ovary. At the end of January two females were obtained in which the polar threads were so far developed as to form projections at the ends of the enclosing follicle. One specimen with eggs in this condition was taken from the aquarium. No perfectly ripe ova were ever obtained. In February moving spermatozoa were discovered in hermaphrodite specimens, but the total quantity of milt present was- quite insignificant. The greater number of the specimens examined were: obtained from fishermen’s lines baited for haddock; some were taken by baited traps. In March dredging was carried on off St. Abb’s Head, with a view to obtain deposited fertilised eggs of Myxine, but none were found. It has thus been shown that Myxine deposits its eggs in the months of December to March, and that the females are taken on the hook imme- diately after the eggs have been shed. But no method has been dis- 252 REPORT—1886. covered of obtaining adults in the ripe condition, or of obtaining the fer- tilised ova and embryos. The research and its results are described in a paper in the ‘ Proceedings of the Royal Society of Edinburgh,’ and more fully in a paper which will appear in the next number of the ‘ Quarterly Journal of Microscopical Science.’ At the beginning of the present year the systematic examination of the ova of all species of fish which could be obtained was commenced. The pelagic ova of the cod, haddock, whiting, and gurnard had been examined in the previous spring, and those of a large number of additional species have now been figured and described at successive stages of development. ‘The results of this work are now being published in full by the Royal Society of Edinburgh, and will appear as a memoir in the Society’s * Transactions.’ (2) The Faunological investigations have been carried on as time per- mitted since the opening of the Station, and have, since June last, been receiving particular attention. A report on the Chetopoda, in the pre- paration of which Mr. G. A. Ramage is giving his assistance, will appear in the coming autumn; a report on the Sponges is being prepared by Mr. J. Arthur Thomson; and miscellaneous notes on other classes will be incorporated with these special reports. (3) The following is a list of those who have carried on studies at the Station :— Name Began Left Subjects 1885. Dr. Kelso, Edinburgh . . | August . | September 26 . | Teleostean ova. And, D. Sloan, Edinburgh . | August 8 . | April 1886 . | Coelenterates. A. H. W. Macdonald, Edin- | October 5 . | November 1885 | General. burgh | G. L. Gulland, Edinburgh . | October 6 . | November 1885 | Crustacea. 1886. G. A. Ramage, Edinburgh .| June3 . — Chzetopoda, &e. J. M.M. Kay, Edinburgh ./ July 24. _— General. Miss Macomish, London . | August2 . -- Mollusca. J. Arthur Thomson, Edin- | August9 . -- Sponges, &c. burgh The yacht is kept up in the same condition as at the opening of the station, and the number of men is unaltered. The ark at Millport is again in use this summer, and is in the charge of Mr. David Robertson. Mr. Cunningham worked there for one week in June, having found at Millport a particularly favourable opportunity for the study of Teleostean ova. Many other naturalists have taken part in the Medusa’s dredgings in the Clyde district during the present summer. The services of Alex. ‘Turbyne, the keeper of the Station, in making excursions in trawlers to . procure fish ova, have been most valuable. All those interested in the Station are greatly indebted to Mr. Robert Irvine, of Royston, for the friendly assistance which he has always been ready to afford on every occasion. Preserved specimens of marine animals and plants are still sent out to applicants, and some attention is being paid to the question of oyster cultivation in the Firth of Forth. J. T. Cunnincuam, B.A., F.R.S.E. ON THE MARINE BIOLOGICAL STATION AT GRANTON, SCOTLAND. 253 Physical marine research has from the commencement formed one of the distinctive features of the Scottish Marine Station. During last year work has been carried on in this direction by Dr. H. R. Mill and Mr. J. T. Morrison ; other gentlemen have occasionally made use of the facilities of the Station. Regular meteorological observations are continued twice daily, and in- clude the temperature at surface and bottom of the water. An elaborate set of experiments with Mr. John Aitkin’s new forms of thermometer screen were completed last year by Mr. H. N. Dickson. Experiments with various anemometers are still in progress. Atmospheric dust is being collected on several islands in the Firth of Forth by means of large funnels and carboys, which are periodically emptied and the contents forwarded to Mr. Murray for examina- tion. Monthly trips along the Firth of Forth for the observation of tempera~ ture and salinity have taken place regularly from river to sea; prelimi- nary results have been communicated to the Royal Society of Edin- burgh from time to time, and a complete discussion of salinity is nearly ready for publication. It shows remarkable relationships between salinity and configuration, which have suggested new definitions of the words river, estuary, and firth. Special attention has been devoted to the relation of salinity and temperature to tidein the estuary of the Forth. Besides the observations of the scientific staff of the Station, thermometer readings are taken by volunteer observers at different parts of the Forth river-system and in the adjacent parts of the North Sea. The Medusa has made regular trips on the Clyde since April last at intervals of two months. Temperature and salinity observations are made in all parts of the estuary and firth from Dumbarton to the North Channel, and in all the connected lochs. These trips have yielded results of great interest and novelty. They are communicated in several papers to various sections of the present meeting. The temperature of two deep: fresh-water lakes—Loch Lomond and Loch Katrine—has been observed at all depths once a month since Novem- ber 1885, in continuation of Mr. J. Y. Buchanan’s work. Daily temperature observations have been established on a number of * rivers and at several points on some. The Station has charge of obser- vations on the Thurso, in the north of Scotland, the Forth and Teith, and the Tweed; and it has also been the means of inducing independent ob- servers to undertake similar work on the Tummel (a tributary of the Tay), the Tay, and the Derwent, in Cumberland. These are all salmon rivers, and the observers being interested in fishing have already suc- ceeded in showing some connection between temperature and the move- ments of salmon. In consequence of experience gained in physical marine investigations the apparatus used for the purpose has been progressively modified and -improved—the Scottish thermometer-frame and water-bottle may be pointed to as special instances. The Station has, since September 1885, been able to advise and assist several public bodies in starting observations of temperature and salinity, the National Fish Culture Association of England, the Dundee Harbour Trust, and the Fishery Board for Scotland being amongst the number. Thermometers have been lent to several naturalists for use on short scientific voyages. 254 REPORT—1886. The collection of all existing records of sea and river temperature round the coast of Scotland is proceeding, and promises when completed to be of great value in showing the different sea-climates of the east and west coasts—a question of much importance in relation to the distribution of marine species. Houex Rosert Mitt, D.Se., F.R.S.E. The Committee beg to recommend that a grant of 100/. be made for the maintenance of the Station during the ensuing year. Report of the Committee, consisting of Professor Ray Lankuster, Mr. P. L. Sciater, Professor M. Foster, Mr. A. SEp@wicx, Professor A. M. Marsnatz, Professor A. C. Happon, Professor Mosgxzy, and Mr. Percy Siapen (Secretary), appointed for the purpose of arranging for the ocewpation of a Table at the Zoological Station at Naples. . Your Committee regret to report that, in consequence of the insufficient -grant voted for their use at the Aberdeen meeting of the British Associa- tion, they have been placed, during the past year, in a very difficuit and undesirable position. Indeed, if they had not been met in the most generous spirit by Professor Dohrn, the Committee would have been unable to carry out the purpose for which they have been appointed during a number of successive years. The following are the facts of the case. Tables in the Zoological Station at Naples are let to foreign Governments and scientific bodies for periods of not less than one year, and at a fixed annual rental, which has for some time been established at 100/.° The table previously at the dis- posal of the Committee had been hired on these terms. At the Aberdeen meeting of the Association, held last year, the sum of only 501. was entrusted to your Committee, and they were consequently unable to hire a table in the usual way. Several informal communications passed between the Committee and Professor Dohrn, and culminated in the two letters subjoined, which your Committee submit for the consideration of the Council. ‘Ewell, Surrey: November 28, 1885. ‘Dear S1r,—I am directed, as Secretary of the Committee for arrang- ing for the occupation of a table at the Zoological Station at Naples, to acquaint you with the fact that the Committee have been entrusted only with 50/. this year by the British Association, which they much regret. e They are aware that it is impossible that you should depart from the principle of the Institution which you have founded, and that you would compromise its interests by letting a table for less than a year, or for less than the regularly established sum of 1002. They therefore propose to present the sum of 50/. to the Direction of the Zoological Station of Naples without any stipulation; but I am instructed to add that they hope, should a naturalist approved by the Committee desire to visit Naples ON THE ZOOLOGICAL STATION AT NAPLES. 255 during the year, that you will be able to receive him as a guest for such period as may be convenient to your arrangements. ‘In the meantime the Committee desire me to assure you that they will use their best efforts to obtain next year the usual grant, which will enable them to lease a table at the Naples Station in the usual way. They further beg you to be assured that the project of the Marine Biological Association for erecting a laboratory at Plymouth has not been the canse of the insufficient grant made by the British Association at Aberdeen, since no grant was applied for or assigned to the Plymouth enterprise this year. ‘T am, dear Sir, ‘ Yours very faithfully, “W. Percy Siapen, ‘ Sec. to the Committee. ‘Prof. Anton Dourv.’ ‘Naples: December 5, 1885. ‘Dear Sir,—In acknowledging the receipt of your communication, dated November 28, on behalf of the Committee for arranging for the occupation of a table at the Zoological Station at Naples, I find it difficult not to begin with the expression of the sincerest gratitude both for the rant of 50. and for the tenor of the communication which informs me of the condition under which the grant is tendered to me. I cannot but consent at once to the propositions the Committee makes therein; and I shall be doubly pleased if you should have to announce to me at the earliest possible date the arrival at Naples of a naturalist whom the Com- mittee desires to see installed at the table, and who will be sure to receive the full share of the advantages which the Zoological Station, its staff, and myself may be able to give him for his scientific work. ‘It is a great satisfaction to me to be assured by the Committee that they will use their influence to continue the table in the usual way. Indeed, as you say, it is essential for the existence of the Zoological Station that the regulations hitherto observed should be maintained. The system of letting tables to different Governments or scientific bodies has been introduced as the best possible means to guarantee the existence of an institution which it would have been difficult to create in any other way on so large a scale. ‘It seems to me beyond doubt that in creating and continuously strengthening one great central institution, a greater good to science is secured than by promiscuously attempting to establish smaller labora- tories on different points of the European coast, without carefully weighing whether such laboratories offer any special advantage, and can be carried to a state of really efficient working order. If available funds existed, every university—nay, every zoologist—might establish a seaside labora- tory for his own private use, and thus pursue with all possible advantage his favourite lines of research. But, as it is, such funds are not ready, and nobody, I dare to say without presumption, can judge better about the difficulties of making them forthcoming than the writer of these lines. The Zoological Station of Naples represents up to this date a capital of 20,0007., and has to provide for a yearly budget of 6,000/. to 7,0001. The efforts it has cost to secure these sums have been considerable. I may be permitted to state that it took seven or eight years of persevering effort to add the recently acquired 4,000/. for the creation of the new 256 REPORT— 1886. physiological laboratory now in course of construction, and I look forward to considerable effort being needed to secure adequate annual sums for working it. It would take more than double the amount of money to create the same facilities for physiological research at any other seaside place, and a much greater annual outlay to carry it to the perfection which may be readily attained by the establishment of this new physio- logical laboratory as part of the already extensive Naples Zoological Station. ‘In stating that the proposed Marine Laboratory at Plymouth did not cause the diminution of the grant for the Naples Station, the Committee seems to place itself on the same principle which I am advocating, viz., that whatever may be the advantages of a greater number of local zoo- logical stations, they can hardly supersede the importance of having access to the greatest and most effective establishment of the kind; and by giving that access to British naturalists also secure the welfare and ever-increasing efficiency of this central biological institution, which to conduct to its highest level will always remain the chief duty of ‘Yours sincerely, ‘Prof. Dr. Anton Dourn. ‘W. Percy Srapen, Hsq., ‘ Secretary to the Committee of the British Association.’ y Your Committee beg to direct the attention of the Council to the liberal manner in which Professor Dohrn has assisted them by generously placing at their disposal the resources of the station as unreservedly as if a table had been hired in the usual way and the customary contribution had been paid. Your Committee trust that the Council will not again leave them with a sum insufficient for the hire of the Naples table, and desire to state that they would not be able again to propose such terms to Professor Dohrn as they have done this year. The Committee would suggest that all sums granted by the Association for the prosecution of marine biology should be assigned in the first. in- stance to the present Committee, and voted in one sum. And they would propose now a grant of 200/., of which 100]. should be appropriated for the hire of a table in the Zoological Station at Naples, and 100I. for the Plymouth laboratory of the Marine Biological Association. The General Collections—The extensive series of marine organisms collected by officers of the Italian navy, mentioned in the last Report, have been placed in the hands of specialists for investigation. The distribution of the collections was undertaken by a Committee appointed by the R. Accademia dei Lincei of Rome, by whom the material has been confided to about sixty naturalists in Belgium, Denmark, Germany, England, Holland, Italy, Austria, Hungary, Russia, and Switzerland. Very few specimens now remain undistributed. The Committee placed no restrictions of any kind upon the use of the material, requesting only the return of specimens not needed for investigation. The Publications of the Station—The progress of the various works undertaken by the station is here summarised :— (1) Of the ‘ Fauna und Flora des Golfes von Neapel’ the following monograph has been published since the last Report :—XIII. Karl Brandt, Koloniebildende Radiolarien (Spherozoéa) (276 pp., 9 plates). ! ON THE ZOOLOGICAL STATION AT NAPLES. 257 The following works are in the press:—J. Fraipont, ‘ Polygordius’ ; H. Hisig, ‘ Capitellide.’ Monographs by G. von Koch on ‘ Gorgoniide,’ by P. Falkenberg on ‘Rhodomelex,’ and by J. W. Spengel on ‘ Balanoglossus’ will subse. quently appear, the plates being now in the press. (2) Of the ‘ Mittheilungen aus der Zoologischen Station zu Neapel’ vol. vi. is completed (756 pp., 32 plates). (3) The ‘ Zoologischer Jahresbericht’ for 1884 (1499 pp.) is published. The editors and the general arrangement of the sections are the same as in the preceding year. The ‘Bericht’ for 1885 is in the press. The index (register) will be given in greater detail than in previous ears. (4) Of the Guide to the Aquarium (printed in German, English, Italian, and French) a second Italian edition has been published. Hztracts from the General Report of the Zoological Station—The officers of the station have courteously furnished lists (1) of the natu- ralists who have occupied tables since the last Report, (2) of the works published during 1885 by naturalists who have worked at the Zoological Station, (3) of the specimens sent out by the station during the past year. These details, which will be found at the end of this Report, are the strongest evidence of the activity and efficiency of the institu- tion. The British Association Table-——During the past year Dr. Robert Scharff, who had been nominated by your Committee, has been kindly allowed by Professor Dohrn to occupy a table for a period of nearly six months (December to May), in accordance with the generous undertaking contained in his letter already quoted. Dr. Scharff has been engaged in several important investigations, the results of which he hopes to publish during the coming winter. His report on the occupation of the table is appended. I. Report on the Occupation of the Table, by Dr. Ropert Scuarer. I commenced my studies at the Zoological Station by taking up the small group of the Chlorhemide. Several species of this group of marine Annelids are pretty abundant in the bay, such as Siphonostoma diplochetum and Stylarioides monilifer. I examined a number of them anatomically, but before I had quite concluded my researches my attention was drawn by Professor Dohrn to a more interesting field of study, namely, the gills of Elasmobranch fishes. Since the publication of the series of articles on the origin of Verte- brates by Professor Dohrn, anything regarding the development and structure of the gills of fishes has been received with much greater inter- est by scientists than formerly. Several organs having now quite a dif- ferent function are stated by Dohrn to have been merely gill-clefts in the ancestral vertebrate. Thus the mouth was primitively a pair of gill-clefts which have coalesced and come to open in front. The organ of smell is also supposed to representa gill-cleft. With regard to the mouth, strong additional support is given to Dohrn’s theory by Beard’s researches on the ‘ Branchial Sense-organs in Ichthyopsida.’ On the other hand, Blane’s as well as Beard’s discoveries do not lend any support to the view of the nose having been a gill-cleft. 1886. 8 258 REPORT—1886. I merely mentioned these facts, without going into further details, in order to show the importance of having an exact knowledge of the histo- logical structure of the gills in order to be able to compare it with that of the other organs mentioned. In the investigation I carried on at Naples during several months the gills of the following Elasmobranch fishes were examined, both fresh and preserved :— Scyllium catulus. Torpedo ocellata. — canicula. — marmorata. Trygon violaceus. Squatina angelus. Raja asterias. Mustelus levis. — clavata. — vulgaris. The general structure and anatomy of the gills are of course well known, and have been the subject of several important papers. The gills of sharks and rays are easily distinguished from the corre- sponding organs of Ganoids and Teleosteans. While the rows of bran- chial leaflets, which are placed upon the branchial arches in the latter two groups project freely into a common cavity covered by the operculum, in the Elasmobranchii they are distributed in separate branchial sacs. Every one of these sacs also has its own opening to the exterior. As in Teleosteans, the branchial leaflets are provided with secondary folds at their sides, in which the true branchial capillaries are to be found, and thus form the principal respiratory surface. The whole branchial leaflet has the form of the blade of a knife. The base is taken up by the artery, the free margin by the vein. ‘The trian- gular shape of the cross-section is somewhat interfered with by the above- mentioned lateral folds, which are placed upon the sides at right angles. They appear as semicircular flaps. The gills, as well as the gill-clefts, contain a large number of mucous cells in their outer cellular layers. As far as I have been able to make out, there are no special cells having a sensory function. In adult gills there are no ciliated cells; in the fully grown embryo of Mustelus, however, the cells covering the lateral flaps of the branchial leaflets were ciliated. At the margin of the gill-cleft I also observed ciliated cells. One of my principal objects in studying the gills of Elasmobranch fishes was to find out the nature of the nerve-endings. I regret that, although I tried a large number of different methods, and much time was spent over it, I was not successful. For general purposes, however, I can recommend the following method of staining with chloride of gold, which did me more good service in tracing nerves than Ranvier’s or any of the other methods :— ‘Place the small object in a watch-glass-full of } per cent. chloride of gold, and add one drop of hydrochloric acid. Leave this in the dark for about half an hour; then, after washing out with water, put the object in a mixture of one part formic acid to four parts water, and expose to light until a violet colour appears.’ A more detailed account of the innervation, as well as the structure of the mucous and other cells composing the cellular layers of the gill-cleft and the branchial leaflets, will be published during the course of next winter. I can only give this very short réswmé at present, having to complete many of my observations by a series of sections which I purpose making shortly. ON THE ZOOLOGICAL STATION AT NAPLES. 259 Il. A List of Naturalists who have worked at the Station, from the end of June 1885 to the end of June 1886. Num- ber on List 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 Naturalist’s Name 4 . Durati Mi State or University ee See ety ‘whose Table was made use of Arrival Departure Prof, Albini . Italy | Jan. 26,1885 | Aug. 22, 1885 Lieut. N. Asbeleff Russia | July 23, ,, Hu Lee Stud. E. Bornand .. = Switzerland Aug.18, ,, June 10,1886 Dr.J.H. Wakker ./| Holland . Sept. 8, ,, | Dec. 1,1885 Dr. O. Hamann. . | Prussia pag) ates Oct. 20, ,, Dr. E. de Daday . | Hungary. Oct. 5, ,, | May 15,1886 Dr. A. Ostroumoff .j| Russia . - a BS SS Mar. 10, _,, Prof. W. Krause | Berlin Academ ee 3, | Dec: 31s 1885 =; A Prussia 3 - | Jan. 1, 1886] Mar. 6,1886 Dr. Monticelli Province of Naples. | Nov. 1, 1885 — Dr. T. Balsamo . Es PS ile IE nee — Lieut. A. Colombo Italy : LS, ost) earl o; 1S86 Dr. R. Semon Prussia . a Ss app a Dr. O. Geise . Saxony Wena, s “ltone dg! 9. Dr. F. Zschokke Switzerland WDeGa Ay) ity gst) Os JH Dr. A. Tickomiroft Russia ‘ . ay ruil. Ts May 16, ,, Dr. R. Scharff . . | British Association . Sena Fo) 3 ae Prof. A. della Valle . | Italy eazilen x, Jan. 17, ,, Prof. W. Preyer. Prussia eee April 21, ,, Dr. G. Jatta Italy Jan. 1, 1886 —_ Dr. J. Raffaele . rf 5 paved eee — Dr. M. de Davidoff Bavaria . So oa. | HAD 2, 1886 Prof. G. von Koch Hesse Heb: 2) _,,. | Miar.26, or), Dr. G. Karsten . Prussia Mars lO; se.) |May 1; -f. Dr L. Will Hamburg a LOS | eApril24. Prof. W. His Saxony oS aes reat i Prof. Kollmann. Switzerland “ye tinier Mays ,%s: Dr. J. Steiner . Baden peer 3, June 5,-,, Dr. Ju. Plate Bavaria . : ee apg May “6; 5; Prof. C. Chun Prussia . : ; Paes re3 sant | pLOAS Cand. J. Dobberke Holland . ArUliGy 3, ele dulysi9, es Mr. W. Heape . Cambridge pee DSA ae June l, ,, Prof A. della Valle Italy AP LG e. May sb, a Dr. Onodi . Hungary . : 3 59. MGs rypy la) (Wrame' 9) t5. Dr. F Nansen . Stazione Zoologica . eee Eee sate Ba ee Dr. F. Schwinck . | Bavaria May 4, , — Prof. A. della Valle . Juuvels, ,, — Italy III. A List of Papers which have been published in the year 1885 by the Naturalists who have occupied Tables at the Zoological Station. Dr. von Sehlen Dr. J. Frenzel. Zur Aetiologie der Alopecia areata. Bd. xcix. 1885. Ueber einige in Seethieren lebende Gregarinen. f. mikr. Anatomie,’ Bd. xxiv. 1885. Ueber die Mitteldarmdriise (Leber) der Mollusken. Ibid. Bd. xxv. 1885. Temperaturmaxima fiir Seethiere. Pfltiger’s ‘ Archiv f. d. ges. Physiologie,’ Bd. xxxvi, 1885. Ueber den Darmcanal der Crustaceen nebst Bemerkungen zur Epithelregeueration. ‘Archiv f. mikr. Anatomie.’ Bd, xxv. 1885. Virchow’s ¢ Archiv,’ * Archiv 52 260 REPORT—1886. Prof.N. Wagner . . Sur quelques points de l’organisation de l’Anchynie. ‘Ar- chives de Zool. Expér.’ t. iii. 2° Série, 1885. Mr. W. Ransom. . On the Cardiac Rhythm of Invertebrata. ‘Journal of Physiology,’ vol. v. 1885. Dr. W. Kiikenthal . . Ueber die lymphoiden Zellen der Anneliden. ‘Jenaische Zeitschr. f. Naturw.,’ Bd. xviii. 1885. Mr. Sidney F. Harmer . Onthe Structure and Development of Loxosoma. ‘ Quart.. Journ. Mier. Science,’ 1885. Prof. C. Chun : - Ueber die cyclische Entwickelung der Siphonophoren. ‘ Sitzungsb. K. Preuss. Acad. Wiss.’ 1885. y : . Ueber die cyclische Entwickelung der Siphonophoren. ; Zweite Mittheil. bid. Dr. L. Orley . : . Die Entozoen der Haie und Rochen. ‘Természetrajzi Fiizetek,’ vol. ix. 1885. a : : . A Czaipaiknak és Réjaknak Belférgei. Ibid. iS Zur Physiologie der Haiembryonen. bid. Dr. J. Walther : . Die gesteinbildenden Kalkalgen des Golfs von Neapeli und die Entstehung structurloser Kalke. ‘ Zeitschr. der deutschen geolog. Gesellschaft,’ 1885. Prof. G. Albini 4 . Sui movimenti dei cromatofori nei Cefalopodi. ‘ Rendi- conto Accad. Scienze Fis. e Mat., Napoli,’ Anno 24,, 1885. M. M. Jaquet . - . Recherches sur le Systeme vasculaire des Annélides, ‘ Mittheil. Zool. Station Neapel,’ Bd. vi. 1885. J. M. de Castellarnan . La Estacion de Napoles y sus Procedimientos para el esamen microscopico, Madrid, 1885. Mr. A.G. Bourne . . Op the supposed communication of the vascular system: with the exterior in Pleurobranchus. ‘ Quart. Journ. , Micr. Science,’ vol. xxv. 1885. Prof. A. Swaen 2 . Etude sur le développement des Feuillets, &c. dans le blastoderme de la Torpille. ‘Extr. Bull. Acad. Roy. Belgique,’ 3° Série, t. 9, 1885. Dr. E. Rohde . : . Die Musculatur der Chaetopoden (Nachtrag). ‘ Zool. Beitrige,’ herausgeg. von Dr. A. Schneider, Breslau, Bd. i. 1885. Dr. A. Gravis . : . Sur les Travaux Botaniques pendant son séjour au Labo- ratoire de la Station Zoologique de Naples (Extr. Bel- gique Horticole, 1884). = 5 - - Procédés Techniques usités 4 la Station Zool. de Naples en 1883 (Extr. du procés-verb. Soc. belg. de Micro- scopie, 1884). Prof. C. Emery 5 . Contribuzioni all’ Ittiologia. ‘Mittheil. Zool Station: Neapel,’ Bd. vi. 1885. Dr. J. T. van Bemmelen. Ueber vermuthliche rudimentiire Kiemenspalten bei Elasmobranchiern. ‘Mittheil. Zool. Station Neapel,” Bd. vi. 1885. Prof. G. Entz . : . Zur niheren Kenntnis der Tintinnoden. Jbid. A. Colombo . ° . Raccolte Zoologiche eseguite dal R. piroscafo Washington nella Campagna abissale talassografica dell’ anno 1885. ‘ Rivista Marittima,’ Aprile 1885. G. Chierchia . . . Collezioni per studi di scienze naturali fatte nel viaggio intorno al mondo dalla R. corvetta ‘ Vettor Pisani,” 1882-345, con 12 tavole e 2 grandi carte zootalasso- grafiche(Estratto dalla ‘ Rivista Marittima,’ Settembre, Ottobre, Novembre, 1885), Roma, 1885. IV. A List of Naturalists to whom Specimens have been sent from the end of June 1885 to the end of June 1886. Lire c.. 1885. July 4 Prof. C.Claus, Vienna. . Various : = . 125°55 5 6 Prof. P. Pavesi, Pavia : . Annelida . . - a9 6 » Landwirthsschaftsschule, Weil- burg. : 2 3 . Ccelenterata A . 344 ON THE ZOOLOGICAL STATION AT NAPLES. 261 Lire ¢. 4885. July 7 Dr. F. Blochmann, Heidelberg . Various . : S810 A » Prof. Askenasy, Heidelberg . Alge . s : A 6:40 os 8 Mr. E. G. Stocker, London . Various F : : 26°65 a » Mr. V. Fri¢é, Prague . 3 . Various : : . 43°80 , 10 Dr. Th. Barrois, Lille - . Mactra ‘ : a 6:05 -p 11 Myr. Ch. Jefferys, Tenby . . Mollusca . : © 203:90 of 15 University, St. Petersburg . Siphonophora . : 66°65 hy 18 Mr. A. Kreidl, Prague ‘ Collection . : . 10735 AS 25 H.R.H. Prince Buppeat of Bavaria . Mollusca . P : 82°90 3 29 Mr. Pernoletti, Beziers : . Octopus ; ’ 76° ¥ 31 Mr. W. E. Hoyle, Edinburgh . Mollusca . ’ . 143°85 x » Marchese Diana, Naples . . Various : 5 41°10 Aug. 8 Prof. Giglioli, Florence. Fishes : : - 70°45 3s 12 Dr. L. eggs Frankfort- -on- Maine . F . Brains of fish ; 2 14:45 » 15 Mr. H. Reichelt, “Leipzig : . Mollusca. : : 9°85 » 16 K. Zool. Sammlung, Munich . Collection . i . 417-55 a 20 Mr. A. Eloffe, Paris . $ . Collection . . 275:10 » 24 Prof. Paladino, Naples. Ovaries of Squatina ~ 12°45 Sept. 4 Prof. D’A.W.Thompson, Dundee Collection . : - 25030 os 9 Mr. V. Frit, Prague . z Ccelenterata ‘ . 106°10 & » Obergymnasium, Sarajevo . Various : ; ; 60°95 3 15 Baron R. von Drasche, Vienna . Various P : P 17°S5 x » Myr.A. Kreidl, Prague 3 . Various ‘ : Z 12: a 16 Mr. E. Marie, Paris . a . Various : 5 . 4740 5 19 Prof. E. Haeckel, Jena . . Collection . ; . 53815 ss 20 Admiral de Kasnakoff . Collection . . : 20° 33 23 Dr. Bolau, Aquarium, Hamburg Living animals . : = 20 Prof sRichiardi. Pisano. . Collection . ‘ . 246°35 55 » Mr. A. Eloffe, Paris . . Various % E 69°70 » 28 Dr. John Beard, Manchester . Embryos of Torpedo E 27°65 oh » Prof. C. Chun, K6nigsberg . Siphonophora . - 10°30 Oct. 5 Prof. C. Vogt, Geneva : . Chimera monstrosa . 13: % 18 Prof. Mohr, Lahr 5 . Collection . i . 179-40 >» 20 Dr. H. J. Veth, Rotterdam . Collection . 5 . 207°85 - » Dr. E. Everts, Hague . . Collection . - 90°15 en » Prof. C. Chun, Konigsberg . Embryos of Torpedo : 17:25 > 21 Mr. J. Puls,Ghent . : . Collection . . 176°55 4, 23 Dr. O. Hamann, Gottingen . Spatangus . , Z 37°50 » 24 Zoolog. Institut, Berlin . Collection . ‘ . 437:°50 Ep » Mr. E. Marie, Paris . F . Various ® : - 102-20 me » Prof. C. K. Hoffmann, Leyden . Engraulis . j ‘ 3°35 >» . 28 Prof. G. Frizzi, Perugia . Mollusca. : : 63°95 = » K.K.Geol. Reichsanstalt, Vienna Corallinea . F : 6-90 Ss » Prof. Hubrecht, Utrecht . . Various 2 52°85 eo Erol Bogdanoff, Moscow . . Ascidiz, Hydromedusee 317-75 of » Dr. Rabl-Riickhard, Berlin . Amphioxus . : i 9:20 Nov. 11 Prof. A. della Valle, Modena . Collection . : . 524-90 A » Prof. Emery, Bologna 5 . Various s 3 . 143°60 fe » Prof. Ehlers, Géttingen . . Various : . : 75:35 oe 13 Dr. Th. Barrois, Lille - . Dentalium . F : 3°60 - 15 Musée d’Histoire Nat., Geneva. Various & 115:05 3 16 Dr. Zograf, Zool. Mus., Moscow Aplysia, Hippocampus 37°75 35 17 Mr. R. Damon, Weymouth : Collection 103-05 % 24 Rev. A.M. Norman . 4 . Collection . , . 335°30 es » Dr. P. Pelseneer, Brussels . . Cymbulia . A i 9°85 “9 28 Mr.Pedro Antigo, Barcelona . Crustacea . A 5 17:10 - », Mason College, Birmingham . Collection . ; . 14210 » .» Ho6here Biirgerschule, Hamburg Collection . - . 250° 3 29 Prof. Newton Parker, Cardiff . Collection . ‘ - 205°35 Dec. 11 University, Warsaw . Collection . 3 . 451°35 ae » Prof. M. Marshall, Manchester . Antedon . f - 38:15 262 1885. 1886. Dec. »” ” Jan. ” 21 22 9 24 ” . »” March 3 4 6 10 11 12 13 16 24 27 REPORT—1886. Dr. Simroth, Leipzig . Pe oe Prof. Gezi Entz, Klausenburg . Prof. D’A. W. er ae Dr. A. Toth, Szegedin Dr. N. Ormandy, Szegedin Prof. Salensky, Odessa Zool. Institut, Munich Laboratoire de Zoologie, Dijon . Mr. F. Riise, Copenhagen . : Prof. Wiedersheim, Heidelberg Mr. E. Marie, Paris Prof. Sabatier, Montpelier Zool. Museum, St. Petersburg Dr. E. Voges, "Heisede Zool. Institut, Berlin Mr. E. Marie, Paris 2 Laboratoire de Zoologie, Lille : Prof. Ludwig, Giessen Mr. J. Tempére, Paris ; Mr. R. Damon, Weymouth Mr. J. Beck, London Dr. von Hanstein, Gottingen Prof. Hertwig, Munich Prof. A. Andres, Milan Dr. L. Eger, Vienna . : . Mr. R. Vallentin, Leytonstone . Prof. A. Batelli, Perugia . Mr. J. B. Jeaffreson, London Dr. O. Hamann, Gottingen Mr, L. Dreyfus, Wiesbaden Inst. de Zoologie, Lille Mr. H. Putze, Hamburg Dr. J. Friih, 8. Gall Mr. H. Knorr, Munich F Morphol. Laboratory, Cambridge Dr. A. Pauly, Munich Mr. E. Simon, Paris . Dr. Mendelsohn, Posen Prof. H. Blanc, Lausanne . Dr. Ed. Pergens, Louvain . Mr. KE. Marie, Paris Zool. Institut, Gdttingen Mr. H. Putze, Hamburg Mr. Kymmel, Riga Mr. A. Kreidl, Prague Prof. Fritsch, Berlin . Prof. A. Goette, Rostock Mr. V. Frié, Prague . Mr. J. Tempére, Paris Prof. G. von Koch, Darmstadt ; Dr. Hering, Frankfort-on-Maine Mr. Pfeiffer, Ehrenfeld Lab. de Zool., Vimereux Veterinir Higskole, Copenhagen Morphol. Lab., Cambridge . Senckenbergisches Mus., Frank- fort-on-Maine Polytechnicum, Zurich Lab. de Zool., Neuchatel Dr, I. Felix, Leipzig Prof. C. Vogt, Geneva Dr. L. Eger, Vienna . Lire c. Collection . 5 - 100° Collection . 3 At) Collection . 3 a 62°55 Pelagia : : - 575 Collection . F o LALO Collection . : . 237-10: Pecten é 4 ; 5°95 Collection . * - 460°95 Mollusca . ‘ 42°35 Heads of Dogfish Us Torpedo, Octopus : 60°45 Collection . 3 . 410-76 Coelenterata ; . 88:10 Collection . : . 125° Collection . : . 425:15 Various j ‘ < 34:25. Various ‘ . 2 25°85. Collection . $ . 625° Various : a P 22°60 Various : F . 13915 Various is : oe h2b* Various : . ‘ 70° Various . 182°95 Strong eylocentrotus 5 46°50: Various § . 3 95°15 Echinodermata . - 13°80: Fishes . : . 63°65 Pycnogonida : : 6°85 Echini *s ’ : 4°45 Collection . ; « ~ 952: Collection . : . 298: Various . ‘ ‘ 62°30 Argonauta . : . 22°85 Corallinea . : 3 ile Various 5 72°85 Animals for Dissection 578°50 Eyes of Pecten . A 6°75 Crustacea . 4 - 21°95 Various Z : . 55: Various ; 5 : 93:90 Bryozoa. 24:90 Pyrosoma, Nemertina 32°35. Echinodermata . . 136:05 Argonauta . : . 22°75 Various E 3 . 162:90 Various ‘ 5 . 64:05 Torpedo : : . 13°75 Ccelenterata ‘ . 6°55 Callianassa . : < 1°85. Various : i . 31°25 Collection . : . 625° Various ‘ ; 7940 Various ; 5 5 71°40 Various , P . 22845 Various 5 ‘ . 128°65 Amphioxus ; . 97°36 Collection . : . 1250: Lepidopus . : | eer Collection . : . 244°35. Various 7 ‘ ; 29°15 Brachiopoda : . 80°70 Corallium . ; 47°30: — 1886. April 22 ” ” 23 28 ON THE ZOOLOGICAL STATION Dr. G. Riem, Halle-on-Saale . Prof. Hofrath Preyer, Jena Oberstaatsanwalt, sae Co- logne . ¢ . Prof. Frizzi, Perugia ¢ Dr. Bolau, Hamburg . : Dr. Pancritius, K6nigsberg University, Columbia, Missouri Dr. Miller, Berlin Zool. Museum, Berlin Dr. Moesch, Ziirich Prof. Frizzi, Perugia . Dr. G. Gilson, Louvain Mr. Jaquet, Jena : Realgymnasium, Zwickau . ; Mr. H. W. Gwatkin, nee ee Dr. Karsch, Berlin Musée a’Hist. Nat., Brussels Prof. Gabor de Baczo, Zilah Mr. J. T. Hillier, Ramsgate Mr. H. Putze, Hamburg Dr. Riickert, Munich Prof. Kupfer, Munich Zool. Institut, Heidelberg . Prof. Chun, Kénigsberg Count Peracca, Turin Zool. Institut, Wiirzburg Prof. D’A.W. Thompson, Dundee Mr. J. Tempére, Paris Mr. P. Antigo, Barcelona . Prof. W. His, Leipzig . Prof. Rabl, Prague Prof. Ray Lankester, London K. Obergymnasium, Szatmar Tyrnan Dr. F. Zschokke, Aaran Istituto Pontano, Naples Mr. Gustav Schneider, Basle Mr. F. Hermann, Naples AT NAPLES. 263 Lire c Various 4 64°10 Echinodermata . 11305 Collection 69°50 Various 8°45 Living Specimens i 25° Intestines Z 29°95 Collection . 436° Collection . 260°85 Collection . 78°55 Various 57°65 Petromyzon 8°75 Testicoli 4°80 Scymnus 12°55 Collection . 105°75 Various 75° Myzostomum 6°40 Fishes : 136:30 Collection . - 50° Various A ; A 38° Various 5 5 31-70 Embryos of Dogtish — Petromyzon : ° 50: Collection . 271°60 Various 2 = ale1-95 Lacerta muralis . n 10: Cardinm 8°85 Collection 161°15 Various ‘ 5 28°40 Various a. : 84°95 Embryos of Dogfish 19°25 27°35 Thysanoteuthis, &e. : 86° Collection . 125° Collection 62°50 Collection . ‘ 44-45 Collection . ; 45° Rhizostoma, Corallium 33°95 Xiphias : : 15° Dy, 781:05 V. A List of Naturalists to whom Microscopic Preparations have been sent from the end of June 1885 to the end of June 1886. 1885. 1886. Oct. Nov. Dec. May Zool. Inst., University, Berlin Dr. O. 8. Jensen, Christiania Prof. W. Newton Parker, Cardiff d University, Warsaw c Miss Garland, Winchester . Lire c. 52 preparations 105- 23 “3 50- 13 “6 31- fd * 25° a8) 4 6:25 264 REPORT— 1886. Report of the Committee, consisting of Mr. Joun CorDEAUX (Secre- tary), Professor A. Newton, Mr. J. A. Harviz-Brown, Mr. WILLIAM EaGLE CLARKE, Mr. R. M. BarrineatTon, and Mr. A. G. Morn, appointed for the purpose of obtaining (with the consent of the Master and Brethren of the Trinity House and the Commissioners of Northern and Irish Lights) observa- tions on the Migration of Birds at Lighthouses and Lightvessels, and of reporting on the same. Tue General Report of the Committee, of which this is an abstract, is comprised in a pamphlet of 173 pages,! and includes observations taken at lighthouses and lightvessels, as well as at several land stations, on the coasts of Great Britain and Ireland and the outlying islands. The best thanks of the Committee are due to their numerous ob- servers for their assistance. Much good work has been rendered by those amongst them who have taken the trouble to forward a leg and wing of such specimens as have been killed against the lanterns, and which they have themselves not been able to identify. This has already led to the determination of several rare birds, which otherwise would have escaped notice. It is evident that unless the birds can be correctly named the value of this inquiry is materially diminished, and ornitho- logists may justly refuse to accept the accuracy of the statements. It is intended, in order to facilitate the sending of wings, to supply the light- keepers with large linen-lined envelopes, ready stamped, and enclosing labels for dates and other particulars. ; The best thanks of the Committee are also tendered to Mr. H. Gatke for the increased interest he has given to their report by forwarding a daily record of the migration of birds as observed at Heligoland between January 1 and December 31, with the concurrent meteorological conditions under which the various phenomena occurred. Altogether 187 stations were supplied with printed schedules for registering the observations, and returns have been sent in from 125. About 267 separate schedules have been sent in to your reporters. The general results, as far as the special object of the inquiry, have been very satisfactory, and much information has also been accumulated respecting the breeding habits of seafowl on the outlying islands and skerries on the Scotch and Irish coasts, and altogether a great mass of facts and valuable data obtained which cannot fail to be of value to future in- quirers. A special point of interest in the report is the large arrival, with a north-east wind, of Pied Flycatchers in the first week in May 1885, observed at Spurn Point, Flamborough Head, the Isle of May, and Pentland Skerries. At Flamborough Head the Flycatchers were accom- panied by male Redstarts in large numbers, both species swarming for two or three days. The immigration at this period was not exclusively confined to these two species. Mr. Agnew, writing from the Isle of May, at the entrance of the Firth of Forth, says, under date of May 3rd—‘ An extraordinary rush of migrants to-day ; have never seen anything like it 1 «Report on the Migration of Birds in the Spring and Autumn of 1885.’ McFar- lane and Erskine, 19 St. James’s Square, Edinburgh. ON THE MIGRATION OF BIRDS. 265 in spring. To attempt to give numbers is simply useless. I will just give you the names in succession: Fieldfares, Redwings, Ring Ouzels, Blackbirds, Lapwings, Dotterels, Rock-pigeons, Hawk, Meadow Pipits, Redstarts, Whinchats, Tree Sparrows, Yellow Wagtails, Ortolan (ob- tained), Robins, Chiff-chaffs, Wood-warbler, Blackcap-warbler, Marsh Tit, Whitethroats, and Pied Flycatchers.’ And on the 4th: ‘Still increasing in numbers, but wind shifted this morning to E. for 8.H.’ A noteworthy incident also of the vernal migration was the great rush of Wheatears observed at the Bahama Bank vessel off the Isle of Man, and at Langness on the night of April 13, when many perished and were captured. On the same night Wheatears were killed at the Coning- beg and Rathlin Island lighthouses, on the Irish coast On the 12th and 13th the rush was very heavy at stations on the west coast of Scotland. No corresponding movement was observed on the east coast of Great Britain on the same night; but at Hanois L. H., Guernsey, on the 10th of May, at night at the north light, and on the Lincolnshire coast and Farn Islands on the 10th and 11th. These entries are sufficient to show the immense area covered by the migration of this species at or about the same period. On the east coast of England the first Wheatears were observed at the Farn Islands on February 22. The autumnal migration is first indicated at Heligoland on July 6, and was continued with slight intermissions up to the end of the year. A similar movement affected the whole of the east coast of Great Britain during the same period, but was apparently less constant and persistent than at Heligoland. It has been remarked in previous reports that the migration of a species extends over many weeks, and in some cases is extended for months. Yet it is observable that, at least on the east coast of England, year by year, the bulk or main body of the birds come in two enormous and almost continuous rushes during the second and third weeks in October and the corresponding weeks in November. In the autumn of 1885 it is again observable that the chief general movements which usually characterise the southward autumnal passage were two in number, and affected the stations over the whole coast line both east and west of Great Britain. The first of these commenced about the 11th ot October, and was continued to the 20th. The second from the 8th to the 12th of November. It is worthy of notice that these two chief movements of the autumn were ushered in by and were con- current with anti-cyclonic conditions, preceded by and ceasing with cyclonic depressions, affecting, more or less, the whole of the British isles. From this it appears not unlikely that birds await the approach of favourable meteorological conditions, of which perhaps their more acute senses give them timely warning to migrate in mass. Whatever may be the cause which impels these enormous rushes, often continuous for days, it is one which operates over an immense area at one and the same time. . The October rush reached its maximum on the 16th, at which date almost all the stations report extraordinary numbers of various species on the wing. As one out of many we quote from the journal of Mr. James Jack, privcipal of the Bell Rock lighthouse : ‘Birds began to arrive at 7.30 p.m., striking lightly and flying off again; numbers went on increasing till midnight, when it seemed that a vast flock had arrived, as they now swarmed in the rays of light, and, striking hard, fell dead on balcony or rebounded into the sea. At 3 4.m. another flock seemed to 266 REPORT—1886. have arrived, as the numbers now increased in density; at the same time all kinds crowded on to the lantern windows, trying to force their way to the light. The noise they made shrieking and battering the windows baffles description. The birds were now apparently in thou- ’ sands; nothing ever seen here like it by us keepers. Wherever there was a light visible in the building they tried to force their way to it. The bedroom windows being open as usual for air all night, they got in and put the lights out. All birds went off at 6 a.m., going W.S.W. Redwings were most in number ; Starlings next; Blackbirds, Fieldfares, and Larks.’ The rush in November chiefly took place in the night ; at. the Bell Rock the movement ceased at midnight of the 12th, and at the Longstone Lighthouse, on the Farn Islands, a little earlier—at 10.30 p.m., when the wind became strong from S.W. From each succeeding year’s statistics we have come to almost similar conclusions regarding the lines of flight—regular and periodically used routes where the migratory hosts are focussed into solid streams. Three: salient lines on the east coast of Scotland are invariably shown, viz., (1) by the entrance of the Firth of Forth, and as far north as Bell Rock, both coming in autumn and leaving in spring; (2) by the Pentland Firth and Peutland Skerries, likewise in spring and autumn; and (8), by the insular groups of Orkney and Shetland, which perhaps may be: looked upon as part of No. 2. On the other hand, three great areas of coast line, including many favourably lighted stations, almost invariably, save in occasionally protracted easterly winds, and even then but rarely, send in no returns, or schedules of the very scantiest description. These- areas are Berwickshire, the whole of the east coast south of the Moray Firth, and Caithness and East Sutherland. Each and all of these areas possess high and precipitous coast lines, if we except the minor estuaries of the rivers Tay and Dee, and a small portion of the lower coast line of Sutherland, which tace towards the east. On the east coast of England these highways are less clearly demon- strated. The Farn Islands, Flamborough Head, and the Spurn are well established points of arrival and departure; but south of the Humber as far as the South Foreland the stream appears continuous along the whole: coast line, and to no single locality can any certain and definite route be assigned. It cannot be said that the southerly flow of autumn migrants is equally distributed along the entire west coast of England.. Gn the contrary, the schedules afford unmistakable evidence that the great majority of these migrants, s> far as the English and Welsh coasts are concerned, are observed at stations sonth of Anglesey. But while the north-west section of the coast is thus less favoured than the rest,. such is not the case with the Isle of Man, which comes in for an important share of the west coast migratory movement. The fact has already been alluded to, that large masses of immigrants from Southern Europe pass. through the Pentland Firth, and, along with migrants from Farée,. Iceland, and Greenland, pass down the west coast of Scotland, whence many cross to Ireland, and it seems most probable that the remainder leave Scotland at some point on the Wigtown coast, and pass by way of the Isle of Man to the west coast of Wales, and thus avoid the English shore of the Irish Sea. The schedules sent in from the coasts of Flint, Cheshire, Lancashire, and Cumberland show that in 1884-85 compara- tively few migrants were observed, and that the great general movement did not affect them in any general degree. These remarks do not apply ON THE MIGRATION OF BIRDS. 267° to migrants among the waders and ducks and geese, which, as a rule. closely follow coast lines, and which are abundantly represented on the Solway and coasts of Cumberland and Lancashire. There is a much used bird route along the north coast of the Bristol Channel, and thence, from the Pembroke coast, across to Wexford, passing the Tuskar Rock, the best Irish station. The fact of a double migration or passage of birds, identical in species, across the North Sea in the spring and autumn both towards the E. and S.E. and to the W. and N.W., is again very clearly shown in the present report. This phenomenon of a cross migration to and from the Continent, proceeding at one and the same time, is regularly recorded on the whole of the east coast of England, but is specially observable at those light- vessels which are stationed in the south-east district ; at the same time, it is invariably persistent and regular year by year. Our most interesting stations are those on small islands or rocks, or lightvessels at a considerable distance from shore, and the regular occur- rence of so many land birds, apparently of weak power of flight, around these lanterns is a matter of surprise to those unacquainted with the facts of migration. No clear indication of the migration of the Redbreast has yet been shown on the Irish coast ; the records of its occurrences are few and scattered. The Black Redstart was recorded at several stations in the southern half of Ireland; specimens were forwarded from Mine Head, The Skelligs, and Rockabill. It is apparently aregular winter visitant to. The Skelligs and Tearaght, generally appearing in October and Novem- ber. The occurrences so far recorded by the Committee of the Black Redstart on the east coast of Great Britain, in the autumn, range between October 23 and November 3. In the spring of the present year Mr. G. Hunt, under date of March 20, reports an extraordinary flight of Rooks at Somerton, on the Norfolk coast, which he observed from 10.30 a.m.to 6p.m. He says: ‘I observed them flying just above the sand-hills, going due south, and as far as the eye could see both before and behind there was nothing but Rooks. There could never for one moment of the day be less than a thousand in sight at one time ; they kept in a thin wavering line. The coast line here runs due north and south.’ Mr. J. H. Gurney reports: ‘I saw the Rooks and Grey Crows on the same day in much smaller numbers as were seen at Somerton, which is fifteen miles further south. I again saw them on the 21st, 22nd, 25th, 26th, and 29th, but none after this date; with us, however, Grey Crows preponderated: the direction was to S.H. An enormous migration of these and many others is recorded from Heligoland, also from Hanover between March 19 and 25.’ In conclusion your Committee wish to thank H.R.H. the Master and the Elder Brethren of the Trinity House, the Commissioners of Northern Lights, and the Commissioners of Irish Lights for their ready co-opera- tion and assistance, through their intelligent officers and men, in this - inquiry. The Committee respectfully request their reappointment. 268 REPORT—1886. Report of the Committee, consisting of Professor CLELAND, Professor McKenprick, Professor Ewart, Professor STrrLInG, Professor BowEr, Dr. Crucnorn, and Professor McInrosu (Secretary), appointed for the purpose of continuing the Researches on Food-Fishes and Invertebrates at the St. Andrews Marine Laboratory. Tue Committee beg to report that the sum of 751., placed at their dis- posal, has for the most part been expended: in the purchase of instruments and books permanently useful in the Laboratory, only a limited proportion having been disbursed for skilled assistance. Since the meeting of the Association at Aberdeen last year several structural improvements in the wooden hospital, now converted into the Laboratory, have been completed, and others are being carried out by the Fishery Board for Scotland. These changes will render the temporary building much more suitable for work. A small yawl of about 21 feet in length has also been added to the apparatus by the Fishery Board. The desiderata now are an increase in the number of good microscopes and other expensive instruments, and an addition to the nucleus of books which workers require always at hand. In this respect the Laboratory has been much indebted to the Earl of Dalhousie, who forwarded a com- plete set of Fishery Blue Books, and to the Trustees of the British Museum, who sent their publications relating to marine zoology. Collections of papers have also been forwarded by many observers, amongst whom Professor Flower, the late Dr. Gwyn Jeffreys, and Pro- fessor Alexander Agassiz are conspicuous. Most of the Continental and American workers in marine zoology and cognate subjects, as well as those of our own country, are indeed represented. The first work of the year was the examination of a fine male Tunny, 9 feet in length, caught in a beam-traw] net near the mouth of the Forth, and the skeleton of which is now being prepared for the University Museum. Various interesting anatomical features came under notice, and its perfect condition enabled a more correct figure of its external appear- ance to be made (vide ‘ Ann. Nat. Hist.’ April and May 1866 and ‘ Fourth Report of the Fishery Board for Scotland,’ plate viii.) The examina- tion of various food- and other fishes in their adult and young conditions was systematically carried out, and notes on the following species will be found in the ‘ Annals of Natural History,’ and the ‘ Report of the Fishery Board’ :—Weever (greater and lesser), shanny, sand-eel, halibut, salmon, common trout, herring, sprat, conger, ballan-wasse, shagreen-ray, piked -dog-fish, and porbeagle-shark. Special attention was also given to the ‘ Mode of Capture of Food-Fishes by Liners,’ ‘ Injuries to Baited Hooks and to Fishes on the Lines,’ ‘ Shrimp-Trawling in the Thames,’ ‘ Sprat- Fishing,’ and to the ‘Eggs and Young of Food- and other Fishes,’ ‘ Diseases of Fishes,’ the ‘ Effect of Storms on the Marine Fauna,’ and ‘Remarks on Invertebrates, including Forms used as Bait.’ ! The active work in connection with the development of fishes for the season may be dated from the middle of January, when one of the local trawlers captured a large mass of the ova of one of the food-fishes, viz., the catfish (Anarrhichas lupus, L.). The embryos in these eggs (which are the size of the salmon’s) were well advanced, so that with the excep- ? Vide ‘Fourth Report of the Fishery Board for Scotland,’ 1886. ON RESEARCHES ON FOOD-FISHES AND INVERTEBRATES. 269 tion of a few unimpregnated ova observed during the trawling experi- ments of 1884, the earlier stages have yet to be examined. The large size of the embryos of the catfish permitted a satisfactory comparison to be instituted between them and the salmon, which had formerly been under examination, and the results, with drawings of both forms, are nearly completed, and will be communicated to one of the Societies during the winter. The first pelagic ova, viz., those of the haddock, made their appearance: during the very cold weather in the beginning of February, and the exa.~ mination of these, together with those of the cod and common flounder— both of which were unusually late—enabled Mr. E. E. Prince and the Secretary to extend considerably the observations of last year. Moreover,. for the first time, the ova of the ling (Molva vulgaris) were examined, and the development followed to a fairly advanced stage. These were procured by a long-line fisherman of Cellardyke (who with others. was supplied with suitable earthenware jars! and encouraged by a visit to the Laboratory), fertilised about 100 miles off the Island of May, and safely brought, after a considerable land-journey, to St. Andrews. The fertilised ova of the plaice and lemon-dab were similarly brought by Captain Burn, late of the Hussars, from the Moray Frith ; for the Labora- tory had then no boat suited for procuring a supply nearer home. No fish, however, has been more useful to the workers this season than the gurnard (Trigla gurnardus), the spawning period of which seems to have been somewhat later than usual. The first ova were procured about the middle of May, and the embryos of the last hatching (middle of August) still swarm in the vessels. Further observations were also made on the ova and young of the lumpsucker, Montagu’s sucker, shanny, stickleback, sand-eel, Cottus, &c. Amongst others the nearly ripe ovum of Ammodytes tobianus has been examined. It is colourless, translucent, and has a beautifully reticulated capsule. Mr. Prince is of opinion that, as sug- gested in the ‘Report of H.M. Trawling Commission,’ it resembles a pelagic egg. Moreover, the information necessary for filling up the gaps between the very early stages of the young food-fishes near the surface and their: appearance off the shore as shoals of young forms more or less easily recognisable specifically has been considerably increased. Much of this knowledge has been obtained by the aid of a huge tow-net of coarse gauze—upwards of twenty feet in length—attached to a triangle of wood, ten feet each way, sunk by a heavy weight and kept steadily at the required depth in fathoms by a galvanised iron float, such as is used for the ends of herring-nets. Since the completion of the net, however, the services of the Fishery Board tender Garland have only once been available, and the yawl has been at our disposal only a few weeks. In these brief opportunities, however, the young of various fishes have been obtained at stages hitherto unknown, and some rare invertebrates and a remarkable Medusa have been captured. Enough, in short, has been seen to indicate the value of this apparatus, and of certain modifications of the ordinary beam-trawl for work on the bottom. The hatching and rearing of the embryos of the common food-fishes have been attended with much greater success than last year or the 1 Containing about a gallon. These were partially filled with pure sea-water then containing fertilised ova, and simply tied over with porous cheese-cloth. °270 REPORT—1886. previous one, and a large series of microscopic preparations (chiefly sections with the Caldwell and rocking microtomes) has been made chiefly by Mr. HE. E. Prince, embracing the entire development of the food-fishes from the early ovum to a late larval stage. The study of these prepara- ‘tions is now being proceeded with ; but in traversing a field so extensive as the embryology of these important Teleosteans a great expenditure of time and labour is required. It is hoped, however, that the results will be completed during the winter.! Since the beginning of June Dr. Scharff has been occupied with the investigation of the intra-ovarian ege of a number of Teleosteans. Among the ovaries examined were those of Trigla gurnardus, Gadus virens and G. luscus, Gadus merlangus, Anarrhichas lupus, Conger vulgaris, Blennius pholis, Lophius piscatorius, and Salmo salar. The researches were made on fresh ovaries and on spirit-specimens. Most of those reserved for section-cutting were previously treated either with picrosulphuric or weak chromic acid. Special attention was paid to the structural changes in the growing nucleus. The origin of the follicular layer surrounding the egg, as well as the origin and development of the yolk, will be dealt with in a paper to be published shortly. Considerable advancement has been made in the study of the develop- ment of the common mussel by Mr. John Wilson. Some of the very early larvee are described in the Report of last year, along with an account of the artificial methods employed. This year embryos were developed for forty days in vessels suitable for microscopic manipulation. Normal growth continued during the first fourteen days. At the end of this period the largest embryos had shell-valves ‘128 mm.in length. They are transparent and almost semicircular, the dorsal (hinge-) line being nearly straight. The powerful velum could be wholly withdrawn within the valves. The alimentary system was conspicuously developed. In the beginning of June great numbers of young mussels were found swimming actively on the very surface of the sea close to the shore, and measuring ‘134 mm. They differed from the most advanced of those artificially reared only in their being more robust, the stage reached being the same in both. At various periods somewhat later in the season many older, though still microscopic, mussels were captured with the tow-net in St. Andrews Bay from the shore seaward for four miles. Besides the careful study of their development, Mr. Wilson has also been engaged with the histology of the mussel (especially that of the generative organs) at various stages, up to the adult condition. The Committee beg to recommend a renewal of the grant (100I.) for the ensuing year. ' Vide for other observations the Annals of Natural History for April, May, June, and August 1886; Nature, June 1886, &c. DEPTH OF PERMANENTLY FROZEN SOIL IN THE POLAR REGIONS. 271 Report of the Committee, consisting of General J. T. WaLKEn, General Sir J. H. Lerroy, Professor Sir W. THomson, Mr. ALEX. Bucaan, Mr. J. Y. Bucnanan, Mr. JouHn Murray, Dr. J. Rak, Mr. H. W. Bates (Secretary), Captain W. J. Dawson, Dr. A. SELWYN, and Mr. C. CARPMAEL, appointed to organise a Systematic In- vestigation of the Depth of the Permanently Frozen Soil in the Polar Regions, its Geographical Limits and Relation to the present Pole of greatest cold. Tue inquiry referred to the Committee necessitated reference to residents in many distant regions, and time must elapse before any large harvest of observations can be hoped for; nevertheless, the Committee are in a position to quote several valuable communications, especially one from Mr. Andrew Flett, adding materially to what was previously known on the sub- ject of the extension of permanently frozen soil, or ground ice, in America. It will be convenient to arrange the data now available in their order of latitude. 1. Lat. 71° 18’ N., long. 156° 24’ W.—At the wintering station of the United States expedition of 1881-2, under Lieutenant P. H, Ray, United States America, that officer found the temperature of the soil 12° F. at 28 feet from the surface, and the same at 38 feet. 2. Lat. 68° N., long. 135° W.—At Fort Macpherson, on Peel River, Mr. Andrew Flett, who passed 12 years there, reports :—‘ The greatest depth of thawed-out earth I came across round that post was 34 feet, October 10, 1865. The greatest depth of frozen ground was 52 feet 3 inches, September 27, 1867, near the mouth of Peel River. The bank had fallen in; at the bottom the perpendicular cliff, which I tried with a boat pole, was frozen as hard as a rock. A black sandy soil. The surface was not above two feet thawed out. The cliff was measured with the tracking line.’ This account leaves it doubtful whether the frost may not have entered the soil from the face of the cliff. On the other hand it is evident that it extended to a greater depth from the surface than was measured. 8. Lat. 67° N., long. 142° W. on the Youcon.—The same gentleman writes:—‘I spent 12 years on the Pelly or Youcon River, on the west side of the Rocky Mountains. Round old Fort Youcon ground ice is found at 6 feet ; this I have seen in the river banks in September where they had caved in; but no particular notice has been taken as: far as I know by anyone, unless it be Chief Factor Robert Campbell, now residing in Merchiston, Strathclair, P.O., Manitoba.’ 4. Lat. 65° N., long. 120° W.—On the Mackenzie River, about ten miles above the mouth of Bear River.—The same gentleman writes :— ‘T have seen many landslips on the Mackenzie, which more frequently takes place in rainy weather; July, August, and sometimes September ; but I never examined them particularly excepting one, which we came near being buried by in camp. This was about August 15,1876. By a pole, I found the bottom of the slide frozen hard, a grey clay and gravel mixed, from where the earth broke off was not over 6 feet. The surface soil sandy. Some way back from the river bank the country is muskeg more or less, and by removing the moss by hand we came to hard frozen ground in August.’ The sentence printed in italic is somewhat ambiguous. It 272 REPORT— 1886. is understood to mean that the bank was not much more than 6 feet high, and was hard frozen at that depth; the depth to which the frost extended is therefore unknown. 5. Lat. 64° 20’ N., long. 124° 15’ W.—On Mackenzie River.—The face of a cliff from which a recent land-slide had occurred was measured by the present reporter in June 1844. The soil was frozen to a depth of 45 feet from the surface (see ‘Magnetic Survey,’ p. 161). 6. Lat. 62° 39’ N., long. 115° 44’ W.—At Fort Rae, on Great Slave Lake.—Captain Dawson, B.A., observed the temperature of the soil monthly at his station of circumpolar observation, 1882-3. The follow- ing table contains his results :— In Degrees Fahr. Months SE ois ole | 1 Foot 2 Feet 3 Feet 4 Feet | 1882. 4 * a Z / September : ; ; 40°6 37°9 3671 34:5 October . i : ; 32°5 32°7 32°5 32°3 November A - 4 23°9 29°1 30°9 31:3 December. F : : 158 24-6 28°8 30°8 1883. January : ‘ , 83 19:9 25:7 28°5 February . ; - ; Mer 21-2 24°5 26°3 March : 3 9°5 20°8 22:7 24:8 April : : 18°9 25°2 24:3 25°3 May. 5 : : ; 34-0 32-0 33°8 30°5 June A F : : 43°5 365 32-4 31°5 July. i j ‘ : 48:0 41:0 37°0 34:5 August . : : : 473 419 38°5 36°5 The mean temperature of the air at 5 feet 10 inches above the surface, in the same months, was as follows :— 1882. 1883. September. : . 4440° Fahr. | February : ; . —10°41° Fahr. October . : . oD O Camas March . : - Pr (aii baie e November ; : a 9:302 as April : , : -)) To 02ses December : A =) — 15209" | May : ; 2 << s96:309:108 June A : - ees) eS 1883. Tulynos »,-. .ite - Seinen January . 5 F su = 26'802. 5 August . - , - ~B6750° +4, We learn from this table that the soil is frozen at a depth of 4 feet from November to June inclusive, and is at the lowest temperature at that depth in March. It further shows that, like the waters of the Scottish lakes, as proved by the observations of Mr. J. Y. Buchanan and Mr. J. F. Morrison in Loch Lomond and Loch Katrine last winter, the mean temperature of the soil reaches its minimum about the time of the vernal equinox. The rise of earth temperature in February above that recorded in either January or March is remarkable. It does not appear from the convergence of the lines when projected that temperatures below 32° F. extend lower than 11 or 12 feet. Captain Dawson writes : ‘ There are two reasons why these earth temperatures are above what is probably the average in that latitude. (1) The ground had a slope of ~; to the S.W.; and (2) it was fully exposed to the rays of the sun; now in most DEPTH OF PERMANENTLY FROZEN SOIL IN THE POLAR REGIONS. 273 places, the ground is either covered with thick moss or shaded by brush- wood, and its surface temperature in the hottest day is not likely to ex- ceed 70° F., whereas earth exposed to the rays of the sun may easily reach a temperature of 120° F.’ Fort Rae is situated on a long arm or inlet of Great Slave, having a depth of 10 or 12 feet of water. 7. Lat. 62°, long. 129° 40’.—Jakutsk, Siberia.—The great depth of permanently frozen soil in this part of the valley of the Lena has long been well known; but the following extract translated from a recent paper by Doctor Alex. Woeikof, of St. Petersburg, entitled ‘Klima von Ost-Siberien,’ contains information on the influence of local conditions which will make it of value to observers, and we therefore reproduce it. ‘The further north,’ he remarks, ‘the longer is the duration of cold in valleys in comparison with that on higher ground. The effect extends to a part of autumn and spring, and is observable in the mean tempera- ture of the year.’ The following observations of earth temperatures are a proof :— At Depth Limit of 20 ft. 50 ft. 300 ft. 381 ft. Frozen Soil Jakutsk ! i ¥13362 79 25:0° 26°6° Fahr. 620 feet Mangan mine « 22:19 25:2° See He 269 ,, Schelou mine ee bed 257° 65 ma 298 ,, Thus, on heights in the vicinity of Jakutsk the earth temperature is from 81° to 86° F. higher than it is in the town and valley at the same depth, and it is even lower at 300 feet in the former than at 50 feet in the latter locality. The total depth of frozen soil is, according to Midden- dorf,? more than twice as great in the valley as it is on the heights; and observe that these lesser heights are in winter relatively colder than higher isolated mountains. Middendorf also states that no frozen soil was found at 60 metres above the level of the river at the mouth of the Maja, in Aldan, but that it was found about four miles and a quarter up the stream at three metres above the level of the river, and that about 28 miles further, in the mountains, there is a deep hollow from which aqueous vapour is constantly rising. Kuppfer asserts that in Bergrivier Nertschinsk, in the Trech Swjatitilei mine, frozen soil was found at a depth of 174 feet, but that in Woss- dwischenst mine, which lies 230 feet higher, the frozen soil ceased at 50 feet. Even in Altai it is acknowledged that many valleys are colder than the neighbouring heights. Dr. Woeikof sums up a number of observations in the following sentences, which apply to the greater part of Hast Siberia, but more particularly to the north-east portion :— (1) As the greater cold coincides with calms and light winds, the valleys and lower grounds are colder than the heights. (2) The temperature of isolated mountains is relatively higher than that of lesser elevations. (3) The lowering of temperature in the valleys is so lasting and considerable that the mean of the year is also lowered, as is proved by the observations of earth temperature. (4) The depth of the frozen soil is greater in valleys than on the neighbouring heights, probably also than it is on the higher mountains. (5) In the Tundras of the far north (answering to the Barren grounds 1 M. Schergin’s shaft. 2 Sibirische Reise, Bd. i. 886. T 274 REPORT—1886. and Muskegs of the North-West Territory of Canada) the winter is warmer than in the valleys of the Forest-zone. Probably because the stronger currents of the air do not permit the cold stratum to remain so long stagnant. 7a. Lat. 61° 53’ 30” N, long. 6° 46’ 30” E. Faleide, Nordfjord, in Norway.—The following memorandum, supplied by a recent tourist in Norway as the result of numerous inquiries on the Nordfjord in about lat. 61° 53’, shows, as we should expect, a remarkable difference in the penetration of frost in a high European latitude. ‘The ground at Faleide (on the Nordfjord) is frozen from one to two and a half feet deep about the Fjord in winter, but this depends upon how soon the snow falls. Higher up the mountains the ground is scarcely frozen at all, owing to the snow falling sooner, and, in fact, if the snow falls very early lower down it is scarcely frozen to any depth.’ 8. Lat. 61° 51’, long. 125° 25’, Fort Simpson, on Mackenzie’s River.— The summer’s heat was found in October 1837 to have thawed the soil to a depth of 11 feet, below which was 6 feet of ground ice (Richardson), making the depth of descent of the frost 17 feet. The result is anomalous ; at other posts in the same region the summer thaw is much more super- ficial. Thus, it will be observed above that in the month of October, at Fort Rae, the soil was at a nearly uniform temperature, but slightly above the freezing point, from the depth of 1 foot to 4 feet. Franklin found a summer thaw of only 22 inches at Great Bear Lake, and the writer was informed that it was only 14 inches at Fort Norman (lat. 64° 41’). Fort Simpson is situated on an island of deep alluvial soil, bearing timber of large size, and possessing an exceptional climate. 9. Lat. 57°, long. 92° 26’, York Factory, Hudson’s Bay.—Sir J. Richardson has stated that the soil was found frozen to a depth of 19 feet 10 inches in October 1835, the surface being thawed to a depth of 2 feet 4 inches. 10. Lat. 55° 57’, long. 107° 24’. Lake a la Crosse.—It is stated that no frozen soil was found in sinking a pit to a depth of 25 feet in 1837, and that the earth was only frozen to a depth of 3 feet in the winter of 1841. Both records are anomalous, and call for verification. 11. Lat. 53° 40’, long. 113° 35’. At Prince Albert, on the Saskatche- wan.—Mr. W. E. Traill, who was in charge of this post in 1872, reports that a settler in the neighbourhood came to frozen ground at a depth of 17 feet, but did not learn whether they passed through the frozen strata, or, if such was the case, what was the thickness of it. The same gentle- man, writing from Lesser Slave Lake (lat. 55° 33’), remarks that he has never come across any indication of perpetual ice during the twenty-two years he has passed in the North-west Territory. 13. Mr. Andrew Flett, writing from Prince Albert, April 21, 1886, says :—‘ Hundreds of wells have been sunk in this settlement ; one I had sunk myself, beginning of July 1881, 27 feet deep; saw no frozen earth. As far as I have noticed on this prairie land, when there is a good fall of snow when the winter sets in, the frost does not penetrate so deep as when there is no snow till late, and in some years very light snow. I had @ pit opened on the 9th inst. (April) ; the surface was thawed 3 inches ; we got through the frozen earth at 4 feet 7 inches. On the 11th inst. I saw a grave dug in the churchyard at Emmanuel College, one mile from my place, 5 feet deep, and had not got through the frost. My place is on higher ground, loam soil.’ DEPTH OF PERMANENTLY FROZEN SOIL IN THE POLAR REGIONS. 275 14, Mr. W. Ramsay settled on the South Saskatchewan, 35 miles from here, sunk a well 40 feet, May 27, 1884; no frost. 15. Mr. Jos. Finlayson, 3 miles from here, sunk a well beginning of July 1882, 46 feet. He saw no frost. 16. Mr. J. D. Mackay, on the same section as the above, sunk a well 27 feet, July 15, 1884, found particles of frozen earth at 7 feet deep. 17. Mr. W. C. Mackay, my next neighbour half a mile west of this, sunk a well abont June 20, 1884; found particles of frozen earth at 5} feet. * 18. Lat. 53° 32’, long>113° 30’. Fort Edmonton, on the Saskatchewan, 2,400 feet above the sea. Dr. James Hector, on March 5, 1858, found the soil frozen to a depth of 7 feet 6 inches.! 19. Lat. 51° 14’, long. 102° 24’. At Yorkton Mr. J. Riaman, when digging a well last summer (1885), found the frost at a depth of 19 and 20 feet, and continuing for a depth of 380 inches. In this case, therefore, the total depth to which frost descended was about 22 feet. Mr. J. Tarbolton, of Yorkton, in communicating the last observation, remarks :— ’ ‘The depth to which frost penetrates during the winter varies, I find, with the character of the winter itself, and with the nature of the locality. T made observations in an open unprotected spot, where there was little or no snow, and found frost to the depth of 5 feet 9 inches. This occurred last July, and the frost was then about 2 feet deep (7.e., had descended to 7 feet 9 inches). But in the bluffs near my house I dug a cellar, at the same time, going down between 8 and 9 feet, encountering no frost at all. ‘This year, however, when digging another well in April, in almost the same place, I encountered frost at 2 feet, and the ground continued solid until I had gone down from 44 to 5 feet from the surface. From this, and from the information I obtained from others, Iam safe in saying that the frost penetrates here to an average of 5 feet, except when we have had a great depth of snow in the beginning of winter, in which case it does not penetrate nearly so far. The bluffs referred to are groves of poplar from 3 to 6 inches in diameter, on the edge of an open plain.’ Mr. Charles Carpmael, Director of the Meteorological Service of Canada, to whom most of the above reports were addressed, remarks :— “We can easily imagine that at a depth of 17 feet at Prince Albert, there might be no frost at all in winter, but owing to the slow travelling down- ward of the wave of cold, it might have reached a depth of 17 feet in the early summer. ‘It is easily seen that the annual mean temperature of the air might be considerably below the freezing point without the occurrence of per- manently frozen soil, for in winter the soil is often covered deep in snow, so that the temperature of the soil might be but little below 32°, although the temperature of the air were 30° or 40° F. below zero. Again, the heat which had entered the soil in summer would only be removed by slow conduction, whereas the summer heat would not only travel down- wards by conduction, but be carried into the soil by percolation of the warm water through the surface.’ 20. Lat. 50° 30’, long. 103° 30’. The Bell farm, near Indian Head.— Frozen soil is said to have been met with in the summer of 1884 at a depth of 124 feet ; details are wanting. 21. Lat. 49° 53’, long. 97° 15’, City of Winnipeg and the neighbour- ' Journal R. G. S. vol. xxx. p."277. 276 REPORT—1886. hood.—Mr. Ch. N. Bell reports that frozen soil has been found as under in various cemeteries :— Brookside Cemetery on the open prairie close to the city, soil rich black loam, varying in depth from one to two feet; subsoil heavy grey clay. On the Higher Ground On the Lower Ground fis sin. fief) ine December 23,1884 . . FrozentoQ 10 240 2, January 3, 1885. 5 - ‘ wee 0 3. (OO March 21 avd et : 5 ‘ a ee 04: 3 66 May 6 A aa j ; : Pa male 4 5 40 June 25 x, Se . Nonedownto6 0 6 0 January 14, 1886 - : . <1 10) AO, Det 6 A farther communication of June 1, 1886, states that the frost only descended 3 feet 6 inches on the higher ground in the winter of 1885-6, and had at that date disappeared. It descended 5 feet in the lower - ground, but had almost disappeared. At St. John’s Cemetery in the city.—‘ I am advised by the clergyman,’ says Mr. Bell, ‘ that frost has been found at from five to eight feet depth ;’ careful investigation will be made there this year. St. Boniface, a suburb of Winnipeg to the east.—The frost penetrates. from five to eight feet, according to the season, varying locally under the conditions of the exposure, tillage, dryness, and heat or frost cracks. During the summer of 1885 frost was found at a depth of five feet, and down to seven feet, when the work was stopped. This was in July or early in August, The locality was probably exposed to the action of the sun. 22. Lat, 49° to 495° long. In the valley of the river Pembina to the extreme south of the North-West Territory.—Dr. Alfred Selwyn, Director of the Geological Survey of Canada, who has two sons settled in this region, states that those gentlemen have had several wells sunk, the deepest about 40 feet, and have never seen any permanently frozen ground. There is similar negative evidence from Brandon, a little further north. It would be premature to draw any general conclusions from the observations thus far collected. There is want of proof of the existence of permanent ground ice beyond the district of Mackenzie’s River in the North-West, but frozen soil has been shown to exist at a depth of 17 feet at Fort Simpson, at Prince Albert, and at Yorkton, and it may be ques- tioned whether the wave of summer heat has time to descend to such a depth before it is overtaken by the refrigerating influence of the early winter. It certainly exists also in the neighbourhood of Hudson’s Bay, on the eastern side, and it is evident that under favourable conditions frost, without being permanent, may in some cases last in the soil all the year round over a wide area, and in other years disappear. At whatever level we locate the maximum of absorbed heat, it must be remembered that when the winter sets in, and freezes the surface, which it does rapidly to the depth of a foot or two, the heat will then be abstracted in both directions, and its rate of descent checked. No expense has been incurred. The Committee recommend that they be reappointed. ON A BATHY-HYPSOGRAPHICAL MAP OF THE BRITISH ISLES. 201 Report of the Committee, consisting of General J. T. WALKER, General Sir J. H. Lerroy, Professor Sir Witt1am Txomson, Mr. Francis Garon, Mr. Avex. Bucuay, Mr. J. Y. Bucwanan, Dr. JOHN Mornay, Mr. H. W. Batss, and Mr. E. G. Ravenstern (Secretary), appointed for the purpose of taking into consideration the Combination of the Ordnance and Admiralty Surveys, and the Production of a Bathy-hypsographical Map of the British Isles. 1. Tuz Committee consider that the production of a plain outline map of the British Isles and surrounding seas, on a scale of 1: 200000 (about three miles to the inch) would be desirable. Rivers, and such other physical features as can be shown in outline, to be marked distinctly. No hill-shading to be introduced. Roads, railways, _ towns, &c., to be indicated faintly, and merely for the purpose of identi- fying localities. Principal heights and depths above and below the datum level of the Ordnance Survey of Great Britain to be inserted. Contours to be drawn at intervals of 200 feet, with subsidiary contours where they are necessary, to give expression to the features of the ground. Incidental features, such as cliffs, &c., to be marked. The map to be tinted according to height. 2. A grant of 251. to be applied for in order that a specimen sheet of the map may be prepared. ; 3. The Clyde Trustees to be approached, with a view to their under- taking the preparation of a similar map of the Clyde estuary ona suitably larger scale. Other harbour boards to be similarly approached. 4, The Committee anticipate that, being provided with maps of this character as specimens of what is required to supply a national want, the Association may be in a better position than at present to move the Government to undertake the preparation of a similar map of the whole of the United Kingdom, based mainly upon the extensive data already available in the archives of the Ordnance Survey and the Admiralty. Report of the Committee, consisting of Sir Joseru D. Hooker, Sir Grorce Nares, Mr. Jonn Murray, General J. T. Waker, Admiral Sir Leoponp McCurntock, Mr. Cirements Marxnam, and Admiral Sir Erasmus Oumanney (Secretary), appointed for the purpose of drawing attention to the desirability of further research in the Antarctic Regions. Your Committee, after having given full Consideration to the great importance of effecting a further exploration of the Antarctic Polar Sea, desire, in the first place, to.express their opinion that it would be most essential, before approaching H.M. Government with the view of urging the expediency of equipping such a naval expedition as would be 278 REPORT—1886. required for the carrying out an exploration of such magnitude, interest, and importance, that the requirements for its success and a plan of operations should be most carefully considered, and the results embodied in a written form for the approval of the Council of the Association and for the information of the Government. Furthermore, in order to obtain the co-operation which the matter requires from eminent men in science, your Committee feel it necessary for their body to be enlarged by the addition of influential members of the Association, and of other bodies representing the various branches of science interested in the investigation of this comparatively unknown region, and especially of the Royal Geographical Society. Your Committee have to point out that our knowledge of the South Polar region is chiefly confined to the grand discoveries effected by that celebrated expedition under the command of Captain Sir James C. Ross, conducted between the years 1839 and 1843 with sailing ships. Since that period the facilities for effecting a more complete research have been greatly augmented by the application of steam propulsion to vessels better adapted for ice navigation. This has been proved by continuous experience in the Arctic seas during the late half-century. For the above reasons your Committee deem it desirable to defer making their report, with a view to giving more definition to the objects sought to be obtained and to the best means of obtaining them, as also to expand this Committee, in order to elicit to the fullest extent the opinions and to secure support from those conversant with the various branches of science which are to be investigated during an exploration which, from its very important and serious nature, eminently merits the favour- able consideration of this great and enterprising maritime nation. Report of the Committee, consisting of Dr. J. H. Guapsronz, (Secretary), Professor Armstrone, Mr. Wirtiam Suan, Mr. StepHEN Bourne, Miss Lypra Becker, Sir Joun Lussock, Bart., Dr. H. W. Crosskry, Sir Ricnarp Trempie, Bart., Sir Henry E. Roscor, Mr. James Hrywoop, and Professor N. Story MAsKELYNE, appointed for the purpose of continuing the inquiries relating to the teaching of Science in Elementary Schools. No steps in advance have been taken by any Government Department towards the more adequate provision for science teaching in elementary schools during the past year. There have been four different Vice- presidents of the Committee of Council on Education during the last twelve months; and Sir Lyon Playfair only came into office after the code for the year had been settled. The annual return of the Education Department for England and Wales issued this year, which deals with the period from September 1, 1884, to August 31, 1885, shows that the present regulations tell un- favourably on the prospects of science. The following statistics for the last three years show that, while the Preferential class subject ‘ English’ is taken in an increasing number of departments year by year, geography shows an actual falling-off, and elementary science seems even to be losing the little footing it had. i ON THE TEACHING OF SCIENCE IN ELEMENTARY SCHOOLS. 279 Needlework shows a steady increase, as it is an obligatory subject in girls’ schools, and it is more advantageous in a financial point of view to take it up as a class subject rather than under Article*109 (c), in which case it necessarily displaces geography or science :— Class Subjects 1882-3 1883-4 1884-5 English . ‘ : . Departments 18,363 19,080 19,431 Geography a ‘ 12,823 12,775 12,336 Elementary Science . ; 35 48 51 45 History . 2 ; j 3 367 382 386 Needlework . ’ : oe 5,286 5,929 6,499 18,524 | 19,137 | 19,266 It must be borne in mind that the figures against ‘ English’ represent in all cases complete departments, although those against the other sub- jects do not necessarily do so, as it is optional to break up the second class subject into two, in which case they count double in the official return. This applies in all cases to history, as it cannot be taken in the lower division; and there are about 3,000 mixed schools in which the boys take geography while the girls take needlework ; there must therefore be some 3,500 departments in which no other class subject but ‘ English’ is taught at all. The anticipated reduction in the teaching of geography or science on account of drawing being made a class subject does not make its appear- ance in the figures of the foregoing table, and it can scarcely be expected to affect sensibly the figures of next year, as the time for the change from the Science and Art Department to the Education Department was post- poned, but a considerable effect will probably be manifest two years hence. In regard to the scientific specific subjects the following are the aumber of children individually examined :— Specific Subjects 1882-3 1883-4 1884-5 Algebra . : ; P . Children 26,547 24,787 25,347 Euclid and Mensuration . ; a 1,942 2,010 1,269 Mechanics A . 4 ‘ 2 a 2,042 3,174 3,527 a BY is t : 5 —_ 206 239 Animal Physiology . : : as 22,759 22,857 20,869 Botany . - : 2 . a 3,280 2,604 2,415 Principles of Agriculture . : - 1,357 1,859 1,481 Chemistry 3 : : ‘ op 1,183 1,047 1,095 Sound, Light, and Heat . : 5 630 1,253 1,231 Magnetism and Electricity . b 3,643 3,244 2,864 Domestic Economy ; ; oa 19,582 21,458 19,437 Extra (Physiography) . : ag _: 16 — 82,965 84,515 79,774 No. of Scholars in Standards V., VI., VII. . | 286,355 325,205 352,860 280 REPORT— 1886. It is evident that while the number of scholars in the higher standards has considerably increased, the number examined in specific (scientific) subjects has considerably decreased; and this decrease has occurred in every subject except mechanics. Algebra and chemistry show rather larger numbers than last year, though not in proportion to the increase of scholars. The comparative decrease in the attention paid to these scientific subjects will be evident from the percentages of children examined :— In 1882-3 ° ° : : : 29-0 per cent. In 1883-4 : ; : 4 Z 26:0 a In 1884-5 5 : : 3 : 22°6 +s but it must be borne in mind that in many schools the children take two subjects, in which case they count accordingly. Increased though still very inadequate attention seems to be paid in the training colleges to the preparation of the students in the science subjects ; the number of individual students who have qualified for teach- ing one or more sciences has risen from 2,205 in 1884 to 2,407 in 1885, and it is satisfactory to note that the increase has been mainly in passes in the first class. The number of papers worked in the several subjects in the two years under review has been as follows :— Number of Papers worked 1884 1885 | Pure Mathematics . s : : : ; - 82 121 Theoretical Mechanics. : 5 F c : 21 25 Sound, Light, and Heat . ; : : : : 488 690 Magnetism and Electricity . 3 , 5 ; 693 551 Inorganic Chemistry 5 ; 4 : ; : 245 269 - a8 practical 4 % - 166 160 Animal Physiology . ; ‘ ; 4 é : 416 257 Botany . : i - : - : : - 485 483 Physiography . ; : E : : ; 1,030 1,095 Principles of Agriculture . : : ’ : ‘ 289 386 The increase has been mainly in sound, light, and heat, and the principles of. agriculture; the falling-off has been chiefly in animal physiology, and magnetism and electricity. : The Scotch Code differs from the English in regard to the teaching of science in several points, but the annual return does not exhibit a much more hopeful state of affairs. The importance of technical instruction is making rapid progress in popular estimation, but this subject has not got a real footing as yet in elementary schools, owing to the inaction of the Government pending a definite expression of opinion by the House of Commons. In the mean- time the Nottingham School Board has started classes for instruction in the use of tools in the workshops of University College, and 106 boys received such lessons during the last quarter; but on applying to the Education Department the Board learnt that, as the code did not recognise such experimental instruction, the two hours per week devoted to it could not be recognised as an attendance. They there- fore drew up a memorial to the following effect :— ‘That your memorialists are of opinion it is very desirable that pro- — ON THE TEACHING OF SCIENCE IN ELEMENTARY SCHOOLS. 281 mising boys should receive some elementary manual instruction before the close of their school career. ‘That your memorialists have established a technical class for boys who have passed through a course of lessons under the Board’s science demonstrator, and are thus specially prepared for this kind of instruction. ‘That the department has informed the Board the code does not recognise such experimental instruction in workshops, and that the two hours per week devoted to such instruction cannot be reckoned as an attendance for the purpose of Article 12. ‘That twenty boys attending the People’s College Higher Grade Board School have been under instruction one half-day per week since October last at the Nottingham University College Technical Workshops, and that the experimental scheme of the Board has worked satisfactorily. ‘That, in the opinion of the Board, the scheme might usefully be extended to the ordinary Board schools, which are also visited by the Board’s science demonstrator. In answer to recent inquiries, ninety-six boys are reported as willing to pay a quarterly fee of 2s. 6d. for instruc- tion at the technical workshops during one half-day per week, whilst sixty-six boys are desirous of attending but are unable to pay the fee. ‘That, inasmuch as technical education, including the use of wood and iron tools, is of as much importance to senior boys as needlewook and practical cookery are to girls, your memorialists respectfully urge the department to sanction elementary technical instruction as part of the recognised school course, and to allow payments for boys thus taught, either by inclusion of the subject as another specific—Schedule IV. and Article 109 (g)—or by making a grant similar to that now given for instruction in cookery—Article 109 (h). ‘Your memorialists would beg your careful consideration of the con- firmatory evidence of the recent Royal Commissioners on Technical Education, who state in their second report (vol. i.) that they are satisfied that such manual work “is very beneficial as a part of the pre- liminary education of boys in this country who are to be subsequently engaged in industrial pursuits” (p. 524). ‘Your commissioners see no reason why, since grants are made on needlework in girls’ schools, they should not be made on manual work in boys’ schools” (p. 524), and recom- mend “that proficiency in the use of tools for working in wood and iron be paid for as a specific subject’ (p. 537).’ This memorial has been supported by the School Boards for London, Birmingham, Gateshead, Huddersfield, Bristol, Swansea, Salford, Derby, Norwich, and Ipswich. The same difficulty has been met with by the London Board in regard-to its experiment in the use of tools, referred to in our last report, though it appears to have given much satisfaction to the boys, their parents, and the Board: it formed the subject of a question by Sir Bernhard Samuelson in the House of Commons, and he has stated his oo of bringing the matter forward again in some more definite ‘form. The earlier age at which children pass their standards in elementary subjects is bringing to the front the question of those who, having passed Standard VII., are willing to remain at school and take up higher subjects. Under present arrangements no grant can be earned from the Education Department for such children, and, although larger grants can be earned from the Science and Art Department, it is a matter of doubt 282 REPORT—1886. whether School Boards can legally expend in teaching such children any sum beyond that of the fees and grants received. In the case of large classes the income from these sources might be sufficient, but in the majority of cases this cannot be secured; and it becomes a matter for consideration whether distinct sanction should not be given by the legis- lature to incurring the necessary expenses for this purpose. Report of the Committee, consisting of Professor SipGwick, Professor FOxwELL, the Rev. W. CUNNINGHAM, and Professor Munro (Secre- tary), on the Regulation of Wages by means of Sliding Seales. Wirs the object of obtaining definite information on the working of sliding scales, your Committee issued a circular to associations of mine-owners and miners in different parts of the country asking for detailed answers on certain aspects of sliding scales. _ Owing to various causes, as yet only a few replies have been received. These replies are, however, very valuable, as they clearly show that each scale has special characteristics of its own, and that no comparison can be instituted be- tween the various scales without taking into account the exact circum- stances under which each scale was framed. For instance, in some districts special allowances in the way of a free house and coal are made to miners, whilst in other districts no such allowances are made. The replies received by your Committee tend to show that in the last-men- tioned districts the non-allowance of a free house and coal was taken into account when the standard rates of wages were fixed, and thus an apparent inequality in two scales is definitely explained. 1. The original standards seem all to have been fixed on a common prin- ciple, viz., to take the price of coal then realised, and the wages then paid, as representing a fair and equitable division of the produce between the mine-owner and the miner, and as giving as high a wage as the industry could then afford. Some districts adopted the price of all coal sold, other districts the price of all coal raised, as the standard price. All the coal that is raised from a mine is not necessarily sold, as out of every 100 tons raised, about twenty tons are not available for the market, part being refuse, part being consumed by the engines that work the mine, and in some cases part going to the miners. No attempt was made to reduce wages to a level, the wages payable at every mine being taken as the standard wage. The real economic difficulty in framing the scale began when it had to be determined what proportion of a rise or-fall in price should go to the men and what to the mine-owners. Both parties contemplated a rise rather than a fall in prices, and the changed condi- tions of the coal and iron industry have exposed the scales to some oppo- sition, but their wise revision from time to time has maintained their influence with both masters and men. 2. (a) Free house and firing are usually given in addition to the wages mentioned in the scales, and in Cumberland, where there are no such allowances, compensation is given by the scale itself in the form of higher rates. Apart from this, local considerations may add to or diminish the standard wages. For instance, if the working of the mine becomes more ON THE REGULATION OF WAGES BY MEANS OF SLIDING SCALES. 283, difficult an addition to the ordinary wages is usually conceded. The con- cession of such addition may be given by the mine-owner himself, but frequently it comes before the Committee or Board of Arbitration charged with the carrying out of the scale, and to whom all disputes are referred. (b) The miner bears the expenses of lamps, powder, and tools, such as picks, shafts, sharping gear, &c. In South Wales this represents a cost of from 3d. to 1s. per week. In Cumberland it is estimated by the miners as averaging 24d. per day, or taking 58} working days for the quarter, 12s. 23d. per quarter. The actual deduction from wages per ton in respect of the above expenses at one colliery in Cumberland was, in 1875, as follows :— d March quarter. 2 : ‘ . 0°69 per ton. June quarter : : : : SM September quarter : . ‘ 2B OAS? cls December quarter : : ‘ HAG Te: In Cumberland the hewers voluntarily contribute one penny per week towards the expenses of carrying on the sliding scale, such as the cost of taking out the quarterly returns. The cost per ton to the hewers in this respect for the year 1885 was as follows :— d. March quarter : 0-11 per ton June quarter ; - E : 2 September quarter * é : eiOPQel 4, December quarter J ‘ ; 240:09y Heys 3. The difficulties in the way of basing a scale not merely on the selling price, but on variable elements in the cost of production are universally admitted; but there is little doubt that when one trade depends on another, variations in the cost of the raw material would require to be taken into account in fixing wages. The coal trade has escaped the difficulty owing to the royalties being fixed for a considerable period of time. But were a sliding scale adopted in other trades it might not be successful, unless the price of raw material were one of the elements on which the division of the produce was made to depend. Further information on this important point is very desirable. 4. Royalties —The principle of the sliding scale does not seem to have been applied to royalties to any great extent, though in some mines the landlord receives a certain proportion of the price as his royalty. The royalty paid varies from 4d. to ls. per ton, averaging about 8d. per ton. Hewers’ wages vary from 7d. to 3s. per ton, though it must be remembered that there are many classes of men other than hewers employed about a mine. Inasmuch as several gentlemen have promised further valuable information on the working of sliding scales, it is desirable that the Committee be reappointed, and it is suggested that in view of the meeting in Manchester next year their inquiries might be extended to the wages lists in the cotton industry. 284 REPORT—1886. Report of the Committee, consisting of Mr. H. W. Bartow, Sir F. J. BRAMWELL, Professor J. THomson, Captain D. Gatton, Mr. B. BakER, Professor W. C. Unwin, Professor A. B. W. KENNEDY, Mr. C. Bartow, Mr. A. T. Arcuison (Secretary), and Professor H. 8. HELE Suaw, for obtaining information with reference to the Endurance of Metals under repeated and varying stresses, and the proper working stresses on Railway Bridges and other structures subject to varying loads. Tue Committee have to report that certain special experiments have been undertaken by Sir J. Fowler and Mr. Benjamin Baker. As, however, these are not yet complete, and the most recent inves- tigations into the question of the endurance of metals now being carried on under the authority of the German Government have not yet reached such a stage that results can be communicated, the Committee request that they may be reappointed. Report of the Committee, consisting of Dr. Garson, Mr. PENGELLY, Mr. F. W. Rupier, and Mr. G. W. Bioxam (Secretary), for imvestigating the Prehistoric Race in the Greek Islands. THE Committee beg to report that during the winter they have obtained the services of Mr. Theodore Bent, a gentleman who has devoted much time and attention to the study and investigation of Greek antiquities. Mr. Bent and his wife spent several months in the Grecian Archipelago last winter and spring, and during the time conducted researches for the Committee at places which they visited. The Committee have much satisfaction in expressing their indebtedness to Mr. and Mrs. Bent for the valuable assistance they have rendered under somewhat difficult circumstances. The work they have been able to do has been carried on with the aid of the grant placed at the disposal of the Committee at the Aberdeen Meeting of the Association, but this has been supplemented by Mr. Bent himself, so that more work has been undertaken than would have been possible with the grant alone. The result of excavations in graves on Amorgos, Antiparos, Anaphi, and Astypalza were similar to those about which Mr. Bent read a paper at the last meeting of the Association, consisting of numerous small marble figures, marble vases, earthenware vases, and obsidian knives of the prehistoric period; in addition to these, a considerable number of skulls and bones were laid aside to be sent with them, the value of the finds far exceeding the outlay, judging by the price given by the British Museum for the things brought home before by Mr. Bent. In addition to this some slight excavations were made at the Temple of Apollo at Anaphi, and some few trifling objects of the Hellenic period were found. The Committee ask for reappointment with a renewal of the grant. i ON THE NORTH-WESTERN TRIBES OF CANADA. 285 Second Report of the Committee, consisting of Dr. E. B. TyLor, Dr. G. M. Dawson, General Sir J. H. Lerroy, Dr. Danie. Witson, Mr. R. G. Hatisurton, and Mr. Georce W. BLoxam (Secretary), appointed for the purpose of investigating and publishing reports on the physical characters, languages, and industrial and social condition of the North-western Tribes of the Dominion of Canada. Tur Committee beg to report that during the past year an extensive correspondence has been carried on with representatives of the Hudson Bay Company, missionaries, and others who are in constant contact with the Indians, and that a large amount of material is gradually being collected. A series of questions is in course of being drawn up, and it is hoped that these will bring in much valuable information during the winter. Mr. Horatio Hale has, unfortunately, been prevented from making his promised visit to the Indian tribes during the past year, but the Committee hope that next spring Mr. Hale will be able to carry out his intention of visiting the North-West, and they have to acknowledge their indebtedness to Mr. Hale for much of the information already collected. Mr. R. G. Haliburton has promised to place at the disposal of the Committee the replies of Canadian Indian agents, through the Indian Department, to circulars sent to them by him in 1870 and 1871, and also a statement of the Chief Factor of the Hudson Bay Company at Queen Charlotte Island respecting the customs, beliefs, &c., of the Indians there. The Committee ask for reappointment. Report to the Council of the Corresponding Societies Committee, consisting of Mr. Francis Garon (Chairman), Professor A. W. Wiuiamson, Captain Dovetas Gatton, Professor Borp Dawkins, Sir Rawson Rawson, Dr. J. G. Garson, Dr. J. Evans, Mr. J. Hopkinson, Professor R. Metpoxa (Secretary), Mr. W. WHITAKER, Mr. G. J. Symons, and General Pitt-Rivers. Tue Corresponding Societies Committee of the British Association beg to submit to the Council a statement of the work done at Aberdeen by the Conference of Delegates, with comments thereon. Two Conferences were held—one on Thursday, September 10, and the _ other on Tuesday, September 15—both meetings having been called at 3.15 p.m., and lasting in each case about one hour. The following is the list of the Delegates nominated, and of the Societies represented by them :— Prof. J. W. H. Trail, M.A. . . Aberdeen Natural History Society. Mr. Thomas Lister . c . Barnsley Naturalists’ Society. Rey. George Robinson - . Belfast Naturalists’ Field Club. Rev. H. Boydon . ; ‘ . Birmingham Natural History and Micro- scopical Society. 286 REPORT—1886. Rey.H.W. Crosskey, LL.D.,F.G.S. Birmingham Philosophical Society. Mr. R. T. Glazebrook, F.R.S. __ . Cambridge Philosophical Society. Dr. C. Vachell . : ; . Cardiff Naturalists’ Society. Dr. J. Gilchrist . : : . Dumfriesshire and Galloway Natural His- tory Society. Dr. J. Howden . : : - East of Scotland Union of Naturalists Societies. Prof. W. Ivison Macadam, F.C.S. Edinburgh Geological Society. Prof. R. Meldola, F.C.S... . Essex Field Club. Mr. J. Barclay Murdoch . . Geological Society of Glasgow. Dr. John Evans, F.R.S. . Hertfordshire Natural History Society. Mr. Alexander Ross . : . Inverness Scientific Society and Field Club Mr. R. L. Tapscott . ‘ . Liverpool Engineering Society. Mr. G. H. Morton, F.G.S. . . Liverpool Geological Society. Mr. Mark Stirrup, F.G.S. . - Manchester Geological Society. Mr. D. Corse Glen, F.G.S. . . Natural History Society of Glasgow. Mr. W. D. Spanton, F.R.C.S. . North Staffordshire Naturalists’ Field Club. Mr. Robert Pullar, F.R.S.E. . Perthshire Society of Natural Science. Mr. R. G. Hobbes ; ; . Rochester Naturalists’ Club. Prof. W. H. Flower, F.R.S. . Royal Geological Society of Cornwall. Mr. Coutts Trotter . . Scottish Geographical Society. Mr. Charles P. Hobkirk, F.LS. . Yorkshire Naturalists’ Union. At the first meeting, Mr. Francis Galton, F.R.S., in the chair, the Secretary, Prof. R. Meldola, read the first report of the Corresponding Societies Committee, which had been presented to the Council, and adopted by the General Committee of the British Association. Methods of procedure were then discussed, and explanations as to the functions of the Conference were given by the Chairman and Secretary in reply to questions or otherwise. In accordance with Rule 7, relating to Corresponding Societies, a short discussion took place, at the invitation of the Chairman, respecting the nature of the work which admitted of being taken up by Local Societies. ' At the second meeting, Mr. Francis Galton, F.R.S., in the chair, the recommendations forwarded by the Secretaries of the Sections, in accord- ance with Rule 7, were read to the Delegates :— From Sscrion C. Erratic Block Committee—‘ That Professors J. Prestwich, W. Boyd Dawkins, T. McK. Hughes, and T. G. Bonney, Dr. H. W. Crosske , and Messrs. C. E. De Rance, H. G. Fordham, J. E. Lee, D. Mackintosh, W. Pengelly, J. Plant, and R. H. Tiddeman be reappointed a Committee for the purpose of recording the position, height above the sea, lithological characters, size, and origin of the Erratic Blocks of England, Wales, and Treland, reporting other matters of interest connected with the same, and taking measures for their preservation ; and that Dr. H. W. Crosskey be the Secretary.’ Underground Water Committee—‘ That Professor E. Hull, Dr. H. W. Crosskey, Captain Douglas Galton, Professor J. Prestwich, and Messrs. James Glaisher, E. B. Marten, G. H. Morton, James Parker, W. Pengelly James Plant, I. Roberts, Fox Strangways, T. 8S. Stooke, G. J. Symotis, W. Topley, Tylden-Wright, E. Wethered, W. Whitaker, and ©. E. De Rance be reappointed a Committee for the purpose of investigating the Circulation of the Underground Waters in the Permeable Formations of England, and the Quality and Quantity of the Water supplied tc various CORRESPONDING SOCIETIES. 287 towns and districts from these formations ; and that Mr. De Rance be the Secretary.’ Sea-Coast Erosion Committee.—‘ That Messrs. R. B. Grantham, C. E. -De Rance, J. B. Redman, W. Topley, W. Whitaker, J. W. Woodall, Major-General Sir A. Clarke, Admiral Sir E. Ommanney, Sir J. N. Douglass, Captain Sir F. J. O. Evans, Captain J. Parsons, Captain W. J. L. Wharton, Professor J. Prestwich, and Messrs. E. Easton, J. S. Valentine, and L. F. Vernon Harcourt be reappointed a Committee for the purpose of inquiring into the Rate of Erosion of the Sea-coasts of England and Wales, and the Influence of the Artificial Abstraction of Shingle or other Material in that action; and that Messrs. C. E. De . Rance and W. Topley be the Secretaries.’ Mr. C. E. De Rance, who attended the Conference on behalf of Sec- tion C, made brief statements explanatory of the work of each of the fore- going Committees, and pointed out the manner in which assistance could be rendered by the Local Societies. He stated that Corresponding Societies or individual members of these willing to assist in the inquiries of any of these three Committees could obtain full particulars on application to himself at 28 Jermyn Street, London, S.W. From Section D. A letter was read from the Secretary of this Section transmitting a recommendation that the subject of the preservation of the native plants of this country should be brought under the notice of the Local Societies, , and deputing Professor W. Hillhouse to bring this subject before the Delegates present at the Conference. In accordance with the foregoing recommendation, Professor Hillhouse gave numerous instances of the extermination of rare plants from certain localities by dealers, to whom their habitat had become known. He stated that, having been empowered by the Sectional Committee to represent their views on this subject, he submitted the following protest :— ‘We view with regret and indignation the more or less complete extirpation of many of our rarest or most interesting native plants. Recognising that this is a subject in which Local Societies of naturalists — will take great interest, and can exercise especial influence, we urge upon the Delegates of Corresponding Societies the importance of extending to plants a little of that protection which is already accorded by Legislature to animals and prehistoric monuments, and of steadily discouraging and, where possible, of preventing any undue removal of such plants from their natural habitats; and we trust that they will bring these views under the notice of their respective Societies.’ From Ssction H. The following recommendation from the Committee of this Section was read by the Secretary of the Conference :— Racial Characters Committee—‘ That Mr. Francis Galton, Dr. Beddoe, Mr. Brabrook, Professor Cunningham, Professor Flower, Mr. J. Park Harrison, Professor A. MacAlister, Dr. Muirhead, Mr. F. W. Rudler, Professor Thane,and Dr. Garson (Secretary) be reappointed a Committee ~ 288 REPORT—1886. for the purpose of defining the Racial Characters of the Inhabitants of the British Isles.’ Dr. Garson, who attended the Conference on behalf of the Section, explained the objects of this Committee, and invited the co-operation of the Local Societies. He stated that particulars respecting the work of this Committee would be obtained on application to himself at the Royal Coliege of Surgeons, Lincoln’s Inn Fields, London, W.C. It was then arranged: (1) That those gentlemen (or, if more con- venient, the Chairman or the Secretary of the Committees they severally represent) should communicate with each of the Delegates as soon as the details of their proposed investigations had been matured. (2) That each Delegate should thereupon do his best to interest the members of his Society, and, if thought desirable, the Society itself, in the subject of investigation, and should send to his correspondent the names and addresses of such persons in his neighbourhood as might be likely to render willing and effectual help, so as to put him at once in direct communication with them. The Committee now beg to report that at their last meeting, held on June 9, 49 applications from Local Societies for enrolment as Correspond- ing Societies were considered, and of these 36 are recommended for election. Twelve of last year’s Corresponding Societies have not yet applied for re-election, but, as this omission may have arisen from an imperfect understanding of the rules, the Committee have communicated with the Secretaries of these Societies in order to receive their explana- tion. 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S98 ‘QUID PIO UeErenb “Hay pus A1ojsiH [wINgeN WIV TONvpunoy Jo eyed pur OIL 1M buypuodseiw0o so woyoayy sof eayrwuon sarzoro0g bupuodsastog oy7 fq pepuewuooory sovjoroog fo ysut pazoojag 1886. 1886. REPORT yoodxsary ‘poy AoT ~19A8 M ‘39048po00 AA ‘MOsduLoT.T, *O + — Kqyoroo0g peordoosoxory [Ood1eayT ‘Ayyenuuwy ‘sto1ovsuvty, *P9 ‘SOT "P9 “SOT 291 overs, "TOodseary ‘uoNqysuy [eAoy | * * “90g ‘OrY [ood ArT Joodz9ary ‘aTepyAryT Jo Ayo100g [BO ‘Ayyenuuy ‘sduyposoorg ‘SLIT ‘PS “SOL 03E Treyortg some ‘uorynqzrysuy pesoy | ‘og TT “FT tood,ary | -rqdosormd pus Areroz1T ‘ood10ayT sloqmoayy Joodaeary ‘490149 WE[NIMA 17 Syyenuwy ‘sdurpeooorg | ‘Soy 10F “ST “71 auoNy #¢ “og'g ‘qqIMaH M "WOIQNgysuy [esoy | * * ‘00g ‘Joep Tood,ary | * * £yjo100g [BoTZ0]Oe4y [ood10Ary (squapnys)"p9'sol yoodasary ‘190199 Ad1Og 61 ‘Aypenuuy ‘suorjovsuviy, pue ‘st ‘71 auoN 8Z1 ‘ION "I semory,y, *worgngiysuy pedo | * * "909 "fT [ood ATT | * Aqo100g Sutteoursuq Tood.1waryt ‘sTTenucy 419)S9010'T *peoy WzAe_ Wopussv[p Aya100g [eo ‘suoyjorsuety, pue s10daxy ‘ST IT ouoNn 00g eBpoT suqor 49 “VT Tosa "£ ‘OD | 008 Ud “WT teyseojeT | -rqdosorrqd pue Axei194TT 104s890]0'T urqng LPT ‘Jo Aqoroog Armb “Ayenuuy *‘yeuinor “11 ouoN O6T *j00149 UJIOMSOTOW og ‘AOTIVE “WM | * puULpery ‘00g "4yuIg | -UT [eIOOg pUB [eOYSEIg “puvecT “ATB urqna¢ ‘edettop TEs -nuuev AT[eiouey ‘"TeuInor LF ey) C eul0N OFT Aqauy, “sow ‘SBllos “£ “MM “JOIg | * PUBTETT ‘00g *108) “Y ‘Jo Ayo1oo0g eorsopoey [eAOY ‘puslory SSoUoAUT G18T “QUID PIONT *A[[VUOTSBOOD “SMOTJOVSUPIT, “sg ouoN O9T Sooyog st ‘oouTeA, semtoTy, | * ‘00g ‘10g ssouteAUy | pus AjolOog oOYIQUEIOg sseuLeAUT *savak a014} ("waz oud) Lormg ‘0923 Io 0&9 A1aAa sBuIpaao01g ‘SOL ‘SOT $8 Dy ‘pleysuudg ‘usmMon ‘aL |* “OH ‘N eepsempoH | * ANTO AIO STA, [BANYVNY OTBpsemjoyy * g 4 . C * urlequnojyy, VUTeIOIY AYLUIOT A pue OILYS-SSOIUTY JO somMvU-s0vTg OY UO SaJON 6 * pueyjoog Jo soinjvay [eorsdyg ayy, (o88I ‘aaapr10q yy 42 Toryeroossy Ysyug JO susp, ye peyqiyxe ‘uoMNoaT[oH uUvoTy) sdey ystyJ009 * - FIOM TRotydersoay pre puvpoog 2 - ; 4 ‘eolyy Yynog ut skeq 10yIO SpoysioyeA\ XOssy WO sdjoN [VUOTIppe sul0g “LHdAVUNOUK)— "fT Uor99ag * "V 'H “T09sqeAA * “GL oerre ay * ‘dM ‘Treysieyy ‘ND “AM ‘TePPrT " "fp "Jorg “SplEH . . “ * [eMtoqpg "VL ‘10D ‘texMog “9 ') ‘Jorg ‘Ies[nog SS a TRSa| Sear | RE RR eS <= Gaeememeeee e e e e ee eee SIL G88 1Og | ° : * gbodaey ‘00 pun Cddy) 11g ‘II quoday yonuuy $03 ‘AI : : * "00 FLT T ‘SUDA, PUD *D0UT FIE ‘THA * PBSYVANGDAT “PU ‘XT “ . . . “ LLI ‘AI . - . “ O16 ae santeS loans Sytat 006 ‘TI : . * "90 5 q1egq 10 Boba oumpo, | UoHPouANA Jo OKT, ‘008 "V ‘0 “A “N ‘BRIS “N . ‘Od “FEN IBFTOT "+ ‘90g '9UNT 1OISIIG ; 009 "HH "N MoSsepy O08 0 (EL Nea : * "Oc" xossa . * "008 “F8N [0jslg "TOS 'N ‘oog ‘sqyTag Aya100g JO OL poyeraerqqy : 3 ° : ‘ * ssoIppy [eluepiserg y.sno'yT 4seyjog Ul esMIM ,10}09}01g, JO vxLOJLUTUTeIO,T JouueYyD [0Isltg oy} Url pepueys Ajoye, ‘(Avrn “wnuondrwy sypshyg) ey UL wouMOD *e% UO SOI0N : * S]USIINO IoyVA\ PUB OINSSOTY PUTAA 09 woye[er UT syUeT JO UOTPVINSYUOH [eUII4X| OT, : * BOLIOULY JO VIOTT OY} WO SoION SUIOSSOTG BISYONT JO SULIOT JUBIIEGW UO SaJON "+ CA Hed) Pley-[e0p [oystag ey Jo BIOL " MOTIEM US Mou pesoddns @ uo sojoN : * sSoIppy [elyUepIserg dodvg Jo ah . somver ‘soyex "fC ‘IQS * “ “WOSTIAA "SV ‘TOSTIM ‘H "M ‘WOSUTATI AA . . M “aq Iq, M ‘MA dt ‘OUT AN ‘d ‘Id ‘Oud Joyny jo omvyy *(panwiyuoo) XNOTOIG—'q worzdag 05 Yyto,7 pue Avy, 3 Ss, G SOCIETIE CORRESPONDIN 4G S r , eA a . UOIUQ “4099 “HT | o49 Fo syeadgy oy} Jo uoTEsyTYyA 10930q 24} UC ‘dA Id ‘OUT bé G8-F8sl col IO,T : : “su, | * * 009 41g "YOUR | * sIIYsvouvyT ur sorsne¢ jo uoteIystulMpy ou |* “SH AA ‘SHBAN 68g ‘TILA : : putnor | * * purpory ‘00g -4e4q | ° * puvjaly Ul ODOBqOT, JO UOTWwATY[ND 943 UC | °* ‘V ¢ ‘SIONTEM. | PLOF[VY PUB JoysoTOUB] UT JOY JUSTOA LEI oe o : c U . co ss -oueg JO WOTQRSIUvSIC, 19}J9G 99 OF paan ouy, | * , “A ‘49009 6g oe ? : : CC : : me sb 2 : : JUSTIUIOAOL) puB UOIeXBy, [ROOT |* ‘HY 'YH ‘Tjeumog FRST PUL FEST UL JOLYSIG: Surpunorzmms G8-FR8T ayj pue JaqysayoURy JO suoMIpuoD [eIO0g I IO ’ : ""SUDuT | * * 009 “4B1QG ‘POUR | puew ormrouoom 93 Jo outos fo uostvdmoD y |* “yz ‘AramMOSyUOTT (uorsseg YIs19-AqI1T}. OY} Fo Suruado £99 fe : * 3 Us : ‘ os is aT} 78 SSoIppY) OYLL puw pueT jo roysuvazy, uc | ° *"f ‘TTouu0goy puryery ut | SUOSIIG UO UOISSIMIMOD TeLoOY 9} FO yxodoyy LT9 es . : as : bh as ey} ur szoolqng oy} jo omos Jo MolAdyY Y |° ‘A ‘Tjouuoqovyy puvypory UI puBy JO a[vQ oY} 0} UOTWleI UL sINpao 909 TIA : : qpuimor | * * purlary 00g “yeyg | -o1g oy} Jo uoroyTdurg oy IoF suoysassng | * "pg ‘qoudry €881-8L1 Ammgueo 694 cr : : ‘ & 0 ‘. se Se ey} suLIMp MOSsepy Jo L109STFT ormepidg ey, }* ‘eid *I94STeLH MOSSELY) FO SOTIOTTVN uojeg ‘¢ pus £9 TIAX ¢ : ero Vere tae "009 ‘TIYq Mossepy | J1y puw UWMesny ay} Jo uoNIsog yuesarg oyT, |“H ‘“f ‘Osx C8-F8sT 68 IO. 5 3 ‘ “ v * 009 “4Rq9 "TOURTT | * : . * worqezuesordey teuoysodorg | ° "Ty ‘yomoporg. 192 NDS OC F “"suouy | * : -qsuy “Sug "N | * - . : SOUT [VOD UT oF] JO sso7T | * * "ECM ‘Pile G88T ‘eoUeTezUOH WOTye1OUNUT 9 t . 6 p c ee ce “ay [VLysnpuy oy} UO suOTeIOpIsuoD omog |‘ ‘Jorg ‘alquyseg AovIYSLsVyy preg yuep -uadapuy ue jo uoTyNyWsqQng oy IoF suOsOS -sng pu ‘maysky Areyunto, yuesord ayy uo G6g ‘TITA ; : qpusnor | * * purely 00g “yVIg | SUOTFVIOpISUOH oUIOS SuTeq ! UMIOFOY TeMoysisey | * “7 AA ‘foqreg S8-P88I Tg IO : : “sum | ° * ‘90g “4RIg ‘oury, | * Louojyy Jo Aroq J, oy} Uo suoAeptsuoy ouog | “y ‘Jorg ‘uosuepy 2 10 Aqa100 asvg Ba MOA, WOryworTqNg JO oT}L, Fe drut, peaeneatetase rode g JO opty, IOYNY Jo oweyy Sane Seen Rees Sol ee Saencemiid Risen BE.) “Tekan ee mL) a | “SOIISILVIG GNV DONATING OINONOOY— yy Uoureg - -—_ 1886. REPORT 306 666 ‘TIAX 8 Set gL TA &6 I 49 ‘TA él TIAX 66 3 Il TA gg TI sit TA 99 "AXXX ¥9 TA 866 “AIX LOS THX 166 ie 986 “ATXXX OFT TIAX T9T “2 &6T “AIXXX I TA 19 TI oSeg 4B gq 10 auunyO A pc i PRPS os ie SS = SG eee See “ee ‘SUDLI, ‘SUD, DUD qvodayy “ “ “SUDMT, “ce * SUDLT, *00U “ “ “ "SUDLT, wOTwoTNd JO ONL “009 "[IYq MOSse[y . be “ * 90g “Gf [ood ary ‘qsuy ‘OOSSy “UIT “MUIOD ‘90g “G “T00d, ArT * "009 "FEN HIPIED * -00g “gf ‘Tood.ary ‘00g ‘TI WoNFy '§ * 909 "gy [00d ATT . . “qsuy ‘pay "NI * 90g “gf ‘TOod AT “ “cs “qsuTy QuUNOD ‘pr "JtoysoyD . . “qsuy ‘Suq N ‘00g “TI MOSSVTH . . “ce “ec . . “qsul ‘Suny ‘N * 90g “@ “ood art "009 “Td WONT “S Ayato0g JO SLL poyeraciqqy . . qy ST] [eUysNpUr Mou v ‘uasTONT Oy} UO + sSurprmg YIM WOTOeUMOD UI 4.TY PUB ddTIOTDG ammjoayIqory pue Suimooursug uwssmjoq diysuoyepy oL UOdTAY} SUOTJVAIASGO YIM ‘aIQ UIT, SuIsset( jo mayskg ysturop oy} Aq pourezqo synsey OU, $ * suOTqRig TeIJUED WoIZ SUIQYSYT OLNOoTH as nt Ena . * asplug uorsuedsng uo0jjI[D OUT, syuemermnbar asnory -aI@\\ 0} ity paesserdmog jo uorjvoyddy aqL IOMOg oynerpApy Jo Apddng orqng WIMssersorg yW999 YT syydeq yuoroyIq ye 107BA\ JO AJTOOTOA 4URAS -U0) IOZ pouULYO B JO WOTJoS-ssoIQ JO WIOg : : : , : * SITOATOSOY AOTAIOG : dueyq Ajoyeg siourpy quoqed , seponod , eq, : * sjag Jo uo1yeiederg oy} pue suttrrenty * s adoy OTM T1109 pexooT OU asey ot} 04 syuemyoR}}V Itey} pur sodoy Surpury Axor[[oD ‘ : ‘ " > dweq Ajo7e9 FIOM OUL SOUTTAL ut duep-o11g Jo soryuenb [ems yo souesead ayy Suyvorput Jo sepoyy pure ‘duwy sopord oUL skVMTIey pure siatg IOATY 1oy TRUST Mou Jo worydr1ose(y - c ‘. + durey qnesieyl oq, auTToORyNL Surporn pue espo\, SUTUTPY 19TT0Y quoyed gyjoulng WIM Su14305-[e0p Fo moyshg Mou VW SUOTIRNITVD ,SAIYY 1OF osn Ul soTNY YWALEBTp OUT, SIOATY YZ PUL YOSTA OY} WO VOTZSEIT eee rodeg Jo OM ‘EONGIOG IVOINVHOGIY—') W019096) * cg «p¢ ‘Keuuey “ * "AA averasplop ‘f "YU “OlAeqoorg HAA ‘ourmoeyy : ‘sy, ‘sueag *q ‘suvaq gg “WOT : ‘np TaSSUITT * +7, ‘uosuvoundg : * +p ‘sepsnoqg “HO ‘orrystqred “ce 6s _ ‘WW ‘ad ‘toqsoyO “ee “ 7 ML “Suroung "g uy ‘uvuBgong . “M Wo ‘UMOIg . . aR *M ‘patg c Ty ‘urarelueg "Vf yep ‘moxeg IOYNV Jo owe yy 307 CORRESPONDING SOCIETIES. ree ee ee OW Xossny * "0 “dV "H ‘N yest0q ‘00g “JUN BIprep . . . “ ‘OW xossoy * “OPEN 9seyog ‘OOSSW “4SaA\ ‘quing : ‘008 °V “HN ‘2u9g . . . - +¢ “Wy xossor 009 ‘[IYd "}VT 1eysoorery . “ “6 * "OHV HN 40sioq uojJaeyG Amnq[ty, ayy wo 90K qaslo( UL sIeT]}0 puv ayfq Aop1ayo0g 10 Aapyoog oy} uo Apuyg yv : b : : : : dup AImqazito A, UleyIg JO SUTvUMAy OLIOYSTY “oI{ IOUT 94} PUe soTyeTOOY oYTUETIOg [ROOT : : * safoqaua(y UO soJON snooueT[eosT * WNOSN]Y Jsej[og UI JouIpaF] yuaTOUY : : : : ; surydrg pu sproysjog SOWBN YSTULOH [BOOT xossqy ‘sABry p00 A, SUVULSUBA UL sefoyouod 0} sjzIStA WO syt0doxy : * BITYSIO]SOOII'T FO sourvu-sovpg ysruvcq JOSIO(T, ‘TOMXO 4v surewmoary o1pyTTesoy, UreyIg TNO Ur asjogq oy uo Apnyg y “THAXX] “AI \ ‘ mes & If TA : Z * 100bq G9 TIAX ‘Suna, pun quodagy OTT “ . . . oe 18 "AT : : * ‘SUDAT, F9E TI ‘0g pun quodaay [8 xX y : SUDLT GSI tS ‘SuDLT, pun qLodaay x “AT : : * "90UT 801 — SUDA], PUD pLodaay Gg é . ° . 6s && TA : ; “00k 8§ TA : ; “SUDA, £63 “ . . . “e IST TIAX : ‘ tes: OOT TA : i * SUDA, LOT ‘TIAX ‘SUDLT, pup ylodary €sT Aes) Se bee LEL “ee . . . “ 9g “ce . . . “e OST BLA . . . “ &&¢ THX ; : * SUDLT 191 a “ ¢ 90d 69 PAI Mi cch nn. 9 Sea SEs “ee . . . “e “ANOTOAOUHINY—' FY woroagy ‘009 “q ‘[ood, ary “ ee "00g THY Mossel "+ 00g “ “Tood ATT "+ 20g FBN BIpIED * ‘qsuy “SUT “Nl "009 “yf ‘Tood, ary “qSUT “FUND “pI *F19}899 7 8 90g “Tyg “uIg . . . “qsuy “sug ‘N . it3 “ YLOMUOIT TBUOTJONIYSMOD WO saqoNy : auTypoeyy, Suryurid-ojyoyg o1nemony ue uo : * stout 10} durey Ayoyzeg o1mjoopy, ue uC SJUBOTIGWT JO WOIJOY oy} pue UOT JO oINYVN 9} WO sayorvesary quooary : : : : * ssUrIplIng Temnqzooqryo1y 6 pur T ‘son ‘durey Ajozeg sxouryy WoT, “BUIGQUIOD eTqnog uosuyor pu oSpozynoy oxy, : y * sdiqg worl pu yeeyg Jo uotons4s “UO puUw UsIsOg oY} WO sUOTyVAIasq() aTIOg ‘ * * aJAaIOUOH yUoMaD puLlyIOg Jo AyIso10g : : : : : * ssolppy [eIyuepIserg sodoyy SUIPULM JO FYSIOA\ OY} Surouepeqrazunog uO “see * sasplig qog pue yIOX MON OUT, YIOM PUNOISIOpUL) LOZ WRig Surpeaery paaordury : : * TogoTMOUIEUY SuruMry-Jjay s,stavq sodox ey YIM SULpUTM 07 sodoy souvregq ie Oe i a ee f DAM WTaAs ‘MIG “areuIg * "gq ‘aay ‘YyIBOg ‘YX ‘Jorg “VlopPw * “A NL ‘semjoH : "gp ‘Touprey * "gy ftosns18 yf , * 7, “qsta09 "M “2109 “T “109.teD) ‘10 ‘AOY «= ‘a.spriqmieg " "AM ‘Ao’ ‘soured " "EE TaqsqoA, “fp ‘org . . "M af TRMG * 89H 'S “H ‘Avegg : ‘d ‘£ ‘woppag : "p ‘aspapqnoyy " *v'd ‘uLssmy% “p ‘UR SIOPL c “OL “AA ‘STIMU : ‘9 ‘oxorureyy "aM ‘Teqsreyy "y ‘Aopsury . “ n iat s Ki i —————— 308 REPORT—1886. Report of the Committee, consisting of Professors ARMSTRONG and: Longe (Secretaries), Sir Wrnttam Tuomson, Lord Rayxeien, Pro- fessors Scuuster, Poyntine, J. J. Tuomson, Fitzceratp, Crum Brown, Ramsay, FRANKLAND, TrupEN, Harriey, McLrop, Carry Foster, Roserts-Austen, Ricker, Reinoip, and §. P. THompson, Captain Asnry, Drs. Guapstons, Hopkinson, and Fiemine, and Messrs. W. N. Suaw, H. B. Dixon, J. T. Borromiry, W. Crookes, Suetrorp Bipwet, and J. Larmor, appointed for the purpose of considering the subject of Electrolysis in its Physical and Che- mical bearings.—Edited by Ourver LopecE. Tur members of the Committee have communicated with each other by correspondence, and have individually undertaken the investigation of various points more or less closely bearing on the subject, some of which were specified by the present editor at the conclusion of a paper on Electrolysis, printed in the annual volume for last year. (See page 765.) The sum of 20/. granted to the Committee has been expended, partly in providing chemicals and simple appliances for experiments, and partly in printing and circulating various interim communications, to wit, letters among the members and letters received from foreign philosophers. The work of the Committee is greatly facilitated by being thus able freely to communicate on matters of interest; and, inasmuch as it is thought desirable to continue this practice, and also to experiment on material of special purity, a somewhat larger grant is asked for this year. Some of the work undertaken by the members is only recently begun, and not yet reported on, but that concerning which an account has been communicated to the Committee is here appended, together with a few abstracts and translations of foreign memoirs, which it seemed desirable to bring together in an accessible form. (For Table of Contents, see p. 412.) Sir William Thomson communicates to the Committee Mr. Thomas Gray’s paper ‘On the Electrolysis of Silver and of Copper, and the application of Electrolysis to the Standardising of Electric Current and Potential Meters,’ as published in the ‘ Philosophical Magazine’ for November 1886; and remarks that it treats of ques- tions referred to in the rest of the Report, especially to those raised by Mr. Shaw in Table IV. on p, 825. Professor Armstrong’s paper ‘On Electrolytic Conduction in relation to Molecular Composition, Valency, and the Nature of Chemical Change: being an attempt to: apply a theory of “Residual Affinity,”’ is published in the ‘ Proceedings of the Royal Society,’ No, 243, 1886. Professor McLeod’s paper ‘ On the Electrolysis of Aqueous Solutions of Sulphuric Acid, with special reference to the forms of oxygen obtained,’ is to be found in the ‘ Journal of the Chemical Society’ for August 1886, vol. xlix. Professor J. J. Thomson and Mr. Newall have been working at Cambridge on con- duction through very bad conductors, such as olive oil, bisulphide of carbon, paraffin oil, &e. They find that for electromotive forces up to 100 volts these conductors obey Ohm's law. This result, they say, is interesting, since Quincke has lately proved ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 309 that for very much greater forces these substances do not obey Ohm’s law: the departure from it being very marked. They also find that the conductivity is improved by raising the temperature. A full account of these experiments is to be communicated to the Royal Society shortly. On Continuity of Electric Conduction. By Dr. Joun Hopkinson, F.R.S. In my experiments on residual charge I touched upon the second question in Dr. Lodge’s programme (‘Is Ohm’s law obeyed by very bad conductors? ’),! and pointed out that Ohm’s law could be regarded as a limiting case of a more general law of superposition. In the case of mechanical after-effects the law of super- position does not hold even approximately. The fourth question (‘Is there any relation between optical opacity and electrolytic conductivity ?’) appears to me to be very intimately associated with the fact that bodies which, if they conducted, would be electrolysed do not follow Maxwell’s law, whereas some other insulators do. My own present impression is that an electrical displacement in glass may, although continuous, be roughly divided into four successive stages. Ist. A yield- ing of the dielectric during a time corresponding to the time of wave-frequency of light, for which K=2}3 about. 2nd. A further yielding during a time correspond- ing to great absorption below the red, bringing K up to from 6 to 10, 8rd. A further slow yielding, partly recoverable, hardly sensible in time Jess than a second or such like, and going on with diminishing amount for days. 4th. A yielding corresponding to an actual decomposition of the material. Superposition probably applies to all these continuously connected successive events. Probably if we could experiment fast enough on any ordinary electrolyte, like solution of CuSO,, we should find a similar succession of phenomena. [ Dr. Hopkinson’s note is of extreme interest, and the references to his papers are as follows: Residual Charge in Leyden Jar, ‘ Phil. Trans.’ January 1877; Strain in Glass Fibre, ‘ Proc. Roy. Soc.’ October 4, 1878; Refractive Index and Specific Inductive Capacity, ‘Phil. Mag.’ April 1882. This last paper I may abstract thus :— Maxwell’s laws are that »*=K, and that transparent bodies must insulate. They are true for mineral oils and solid paraffin; not true for glass, Iceland spar, and organic oils. Consider, for instance, light flint glass: K is 6:7 for disturbances whose period is longer than 10-° second, and for these disturbances it behaves as an insulator. It ought, therefore, for such waves to be transparent, and to have an index 2°6. But, for disturbances of period about 10-! second, its index, reckoned for very long waves by extrapolation formula, comes out about 1:5. Is there any way of accounting for this discrepancy? Yes; perhaps by the known fact that on waves between these two periods glass exercises a strong selective absorption, and that this is usually accompanied by anomalous dispersion; which at once renders all empirical reasoning towards the state of things for very long waves, from the observed condition for very short waves, utterly futile and misleading. Perhaps, therefore, Maxwell's law is after all obeyed by these substances for long waves ; and one way to test the question is by using rays from a thermopile to a freezing mixture. O. L.] On Diathermancy and Electrolytic Conductivity. By SHetrorp Bipwett, F.R.S. The following is one of the questions suggested by Dr. Lodge for the considera- tion of the Committee on electrolysis:—Is there any relation between optical opacity and electrolytic conductivity ? ? Assuming that ‘optical opacity’ is included in the more comprehensive term “opacity to radiation,’ I have endeavoured to ascertain experimentally whether 1 See Brit. Assoc. Report for 1885, p. 765. 2 Thid. p. 768. 310 REPORT—1886. those electrolytes which transmit radiation with the greatest facility, as evidenced by the effect produced upon a thermopile, are also the worst conductors of electri- city. I may say at once that this was undoubtedly not the fact, and the relation which was supposed to be possible does not exist. Considerable time and care were bestowed upon the experiments, and every precaution was taken with the view of ensuring accuracy. The thermopile used was a delicate one, containing 54 bismuth-antimony pairs; it was enclosed in a flannel-covered box, fitted with a pane of glass 1:‘5'mm. thick opposite the face of the pile. The galyanometer was an astatic reflecting instrument of ‘545 ohm resistance made by Elliott. The source of radiation was a small paraffin lamp, haying a glass chimney about 2 mm. thick. The parallel glass sides of the cells, used to contain the liquids, were 13 mm. apart, and 1‘9 mm. in thickness. A screen, with a small aperture, which could be: instantly opened or closed by a sliding shutter, was interposed between the cell in use and the lamp. The various solutions were in every case exposed to radiation for a period of 50 seconds, and each observation was checked and standardised by the aid of a certain cell containing water. It is hardly necessary to describe the arrangements and method of observation in greater detail. A few of the results, which, for the most part, need no comment, are given in the following table :— Solutions, &c. Diathermancy. Empty cell . - ; : : : : : ; . 1000 Water distilled . : : . : 5 F : peed! Se » fromtap . ; ¢ : ; : : : . 200 Alum, saturated solution § P : P : : . 204 Ammonium chloride solution ‘ : : : ; i 2d Zine sulphate sol. sp. 2r. 1157. : : ‘ . Semi LUE Sulph. acid 1:032 (5 per cent.) |. 3 é : ; i 208 ¥ Sel l2212)5)(G] Up Aaa) Oe - : epsh es Fait 2 Me *s Se EcHich (ue) ene : : ‘ : . 292 The observations with sulphuric acid are the most instructive. It is well known that the electrical conductivity of sulphuric acid at first increases with the concentra- tion, reaching a maximum when the strength of the solution is about 30 per cent., and afterwards rapidly diminishing. That there is no corresponding minimum diathermancy appears clearly enough from the above table, which seems to furnish a conclusive answer in the negative to the question proposed. The diathermancy of a solution of zinc sulphate was almost independent of its strength, being nearly the same for a 5 per cent. as for a saturated solution. It was quite unaffected by the passage through the solution of a strong battery current. Translation of Letters received from Dr. ARRHENIUS. By Oliver Lodge. POLYTECHNICUM, RIGA, May 17, 1886. Dear Sr1r,—I have been much interested in your electrolysis memoir, and since it seems intended to open a discussion, I beg to be allowed to express my views on a few important questions there touched on, especially concerning wandering of ions. As Ihave shown, and a little later also Bouty, one must regard all positive ions, in extremely dilute solutions, as possessing nearly equal velocities ; and in the same way also all negative elements as having an equally great velocity among themselves. It is very probable that these two velocities are also equal to each other for those salts which, by reason of excessive dilution, already approximate closely to the ideal condition; that is to say, the best conducting salts like KCl, NH,Cl, &c.,. whose ions have nearly equal velocities. One could best represent the ions to oneself as spheres of about equal size (though of unequal weight) which are urged through a resisting medium with the same force, and which very soon attain their terminal velocity. But if the motion ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 311 of the ions is disturbed by collision with other ions (or molecules), a certain de- parture from equal velocities will arise. This departure is, nevertheless, so small that it cannot be regarded as accurately established. But if one considers greater concentration, the molecules are jammed together, 1020 to a degree which may be represented by x 10-8, where p is the molecular conductivity of the given concentration. Thus arise double* molecules, treble molecules, and so forth. The electrolysis of a double molecule 1,J, occurs either according to the scheme I+ IJ,, or according to the scheme I,J +J; though indeed the former occurs much the more often, To take an example: if all the molecules in a solution are double molecules, then, according to the first alternative (if one assumes all ions to travel at the same pace, which is nearly correct), analysis will show that I remains quite still (i.e. it. wanders equally in opposite directions), and the whole motion is performed by’ J, According to the second alternative, one is led direct to the opposite result, If part is decomposed under scheme 1 and the rest under scheme 2, all intermediate conditions can be represented. This is, I believe, the true cause of the so-called unequal wandering of the ions. That water has an extremely small conductivity, itschemical behaviour makes clear. Indeed it will probably never be detected by electrolysis. The phenomena accompanying the electrolysis of CuSO, are explicable in the simplest way by supposing that CuSO, is decomposed by water, even though but very little (one Imows that CuSO, has an acid reaction), and naturally the so-formed sulphuric acid takes part in the electrolysis, whence arises the free acid at anode. This will after all be scarcely noticeable. With stronger currents H,SO, appears at the kathode, and the hydrogen of this will be gradually transported to the anode by electrolysis. The experiment with MgSO, can be explained in a similar way, without supposing a noticeable electrolysis of water. The dilute solution contains much more free H,SO, than the concentrated, So if a current flows according to annexed scheme— <_—_—KE MgsO, 2 ’ . MgSO, MgSO, . : ‘ . MgSO, H,SO, MgSO, H,S0, H’SO, dilute sol. strong sol. the left-hand side of the partition will lose two H,SO, and gain one, so the solu- tion will become alkaline; whereupon Mg(OH),, which is only soluble in excess of acid, will precipitate. This Mg(OH), we can neglect in electrolysis, for it probably conducts no better than NH,. Besides, CO, in the solution could cause a small precipitate of Mg0O,. I should be very glad to hear your view of the expositions in my essay, if you will kindly pass an opinion on it. You will probably think my enunciations too bold, and that I have insufficiently established my conclusions; meanwhile, I may refer to the work of Ostwald, who has found my statements, in § 15 of the second part, to fully correspond with experiment ; also, I can refer to the simultaneous work of Bouty (February 1884; my work was undertaken June 6, 1883), and the later investigations of Kohlrausch, which completely prove that with extreme dilution all salts examined conduct about equally well (Part I. page 41, law 3). Tt follows moreover from Ostwald’s experiments that the law 41 (Part II. p. 46), which I have deduced from purely theoretic considerations, corresponds exactly with experience. I hope that these circumstances will mitigate your criticism of the many incompletenesses, since they show that 1 have gone at least partly on right lines, 1 First part, ‘On the Conductivity of very Dilute Solutions’; second part, ‘On the Chemical Theory of Electrolytes.’—Acad. des Sciences de Suede, June 1883. See below, page 357. 312 REPORT—1886. although I have not had the power of setting forth with sufficient clearness what is abundantly evident to myself. With assurances that I shall be grateful to learn your views, &e., &c. SvanTE ARRHENIUS. RieGA, June 8, 1886. Dear S1r,—Thanks for note and British Association circulars. Since you speak of communicating something of my views to the Committee, I will, to avoid misunderstanding, just try in a few lines to explain my position. In my small notice on the conductivity of gelatinous solutions, I am led to the view that internal friction (viscosity) exerts no influence on conductivity. By experiments on the conductivity of mixtures, with which I am now working, it appears, however, that gelatinous solutions (and probably other pseudo-solutions) form an exception ; since for other (actual) solutions a very close relation exists between conductivity and limpidity. It seems as if, when one adds to water a liquid, or in general any foreign body (with the exception of all the best conducting salts), the limpidity of the solution becomes less than that of pure water, no matter whether the limpidity of the added body be less or greater than the water. It appears as though the friction experienced by a molecule travelling through a liquid greatly depends on the heterogeneity of the liquid. One could propel a water molecule more easily through pure water than through water with which some other substance had been mixed. But a water molecule consists of the ions H and OH, and what is valid for the whole molecule must be valid also for a part of it. If this is correct, the advance of an ion through a liquid whose molecules have this ion as a constituent must be opposed by a smaller resistance (friction) than if the molecules of the liquid had not, or only partly had, this ion as a constituent. This serves as a sort of explanation of the greater velocity of the ions H and OH in aqueous solutions in comparison with the velocity of other ions. I regard it as certain that the ions H and OH travel quicker than other ions, which go at a pace pretty nearly equal (not quite equal) among themselves. But the influence of heterogeneity on the internal friction and also on conductivity appears to diminish with increasing temperature. So it is very possible, and indeed probable, that at some temperature, higher than any hitherto employed in such observations, the ideal case might be reached when all ions should go at the same rate—which would mean that at that temperature all electrolytes, in extremely dilute solutions, should conduct equally well ;. just as a gas’s obedience to Boyle’s law approaches exactitude at low pressures and high temperatures. This will probably be the tendency of the results of my not yet concluded investigation on this interesting subject. It is impossible for me to give you the experimental proof for the view above expressed, though I should have had much pleasure in doing so. I should be obliged by your sending me the results and report of the Committee, and on my side I will willingly, if you regard this as not wholly without value, communicate to the Committee the results of my experiments now being carried on. Professor Ostwald is sending you some of his papers. Yours &e., Dr. SvANTE ARRHENIUS. On the Accwracy of Ohm’s Law in Electrolytes. By Professor G. F. Firzcrraup, F.R.S., and Mr. Trovron. Some preliminary experiments were begun in the spring of this year, and have been carried on from time to time since, with a view to determining how far Ohm’s law may be relied on in the case of electrolytes. Though as yet no very high limits of accuracy in the experiments have been attained, owing to causes which will be later on explained, still it is hoped that from the experience already gained most of the difficulties have been got over, and that soon results of a much greater degree of accuracy will be arrived at. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. als The method adopted is that described in the British Association Report for ‘Glasgow, 1876, which Professor Chrystal, in connection with Clerk Maxwell, em- ployed in the case of metal conductors, namely, that of a Wheatstone’s bridge, two of the arms of which are of about equal section and resistance, while the remaining two, though of equal resistance, are of very different sections. If Ohm’s law be not true, the point of balance of the bridge varies with the amount of current passing through it. Balance having been obtained, the battery-power is altered, and if balance still subsists, the deviation from Ohm’s law, if there be any, is such as cannot be detected with apparatus of the sensitiveness employed. The great difficulty in experimenting in this way is that the change in the -current alters the temperature of the two arms of unequal section very differently, and proportionately also their resistances. While the thick conductor alters little in temperature, the thin one alters considerably. Thus the point of balance is changed, even though Ohm’s law be true. To avoid this effect it is necessary, having balanced with the large current, to immediately pass the smaller current before the temperature can sensibly alter. As this requirement is practically im- possible to satisfactorily fulfil, the method employed is a rapid alternation of a large and small current. IfOhm’s law be not true, a balance in this case can only be apparent, and on reversing the direction of one of them, the two currents which ‘before neutralised each other's action now conspire to deflect the galvanometer. The mode of experimenting is to find balance with a large and a small battery alternately in circuit, and rapidly enough for the temperature during the smaller -current to be sensibly the same as while the larger one is acting, then to change the direction of one of the currents and to again balance. The distance is observed between the two points of balancing, but if the bridge still balances it is assumed for the purposes of calculation that the distance is what the galvanometer employed only just detects. From this, from the two currents the section and resistance of the thin conductor, 2 is calculated, where e =7c(1 — Ac’), as is explained in the above- mentioned Report. The liquid, chosen for experimenting with, was a solution of copper sulphate in water. The equal arms consisted of two glass tubes bent at right angles at each end, A and B, arranged syphon-like, and contained the solution. They dipped into a long narrow trough, as shown in the diagram. The arm of large section C, a tube 119 cm. long and 2°38 cm. in internal diameter, reached from the bowl D ‘into which the tube A also dipped, to the bowl E. The small arm was a hole ‘055 cm. in diameter, drilled in the side of the beaker F, ‘063 cm. in thickness, into which the tube B dipped. The battery poles consisted of copper plates, one in the beaker, the other in the owl D. The contact breaker was a T piece worked by an electromagnet and cell 314 REPORT—1886. K, as shown in the diagram. One of the batteries contained ten Grove cells, the: other five, and both could be thrown in circuit in either direction by means of the- reversing keys Mand N. By proper adjustment of the mercury cups P and Q one: of the batteries went in circuit, just as the dipper on the other side, coming out of the mercury, threw the second battery out of circuit. By means of the galvano-- meters H and I it could be seen, during the course of an experiment, whether the contacts were working properly or not. One of the copper wires leading to the galvanometer dipped into the bowl E, the other into the trough, and could be moved up and down it in order to obtain balance, the distance moved being read off a scale along the trough. There was always more or less of a permanent current through the galvanometer, even though. the poles were both of copper ; this especially, as it was liable to sudden changes in amount, caused by moving the trough pole or by accidental shaking, necessitated the employment of the galvanometer in a comparatively insensitive condition.. Various devices were tried with a view of avoiding this current, such as electro- plating the poles, using chemically pure copper sulphate, or employing for poles. either end of a broken wire, so as to have, if possible, metallically like poles; these were found to give an indication of current even in distilled water. The resistance of the smaller arm was about 800 ohms, but owing to its small-- ness varied greatly with the current through the change of temperature. A good deal of trouble was experienced through the resistance of the smaller arm at times, being less when the current passed in one direction than when it passed in the other. This occurred so often that until its cause was understood, and steps thus could be taken to prevent it, there was little hope of completing the experi- ments, After various attempts it was discovered to be due to the density of the solution on the outside of the beaker in the bowl being slightly different from that inside, so that the density in the hole, and consequently its resistance, depended on the direction of the current, the electric transfusion of the liquid always changing direction with the current. A number of experiments were made of a more or less satisfactory nature; in all no difference in the position of balance was found on reversing one of the- batteries. Taking the difference then to be what the galyanometer would just detect, 2 is calculated to be less than 10-*. This is, of course, very large. The limit Professor Chrystal reached in his experiments with metal conductors was less. than 10-?*, With a view to reaching a higher limit a smaller hole was next tried. It was ‘017 cm. in diameter, drilled in a plate of glass ‘022 cm. thick. Its resistance was about 2700 ohms, so that a longer tube had to be used for the large arm. The balance was always found to be very different when one of the batteries was. changed in direction. However, this was probably entirely due to the difference in temperature during the small and large currents, for / calculated from this was not even as small as in the first experiments; also the difference between the balance points varied with the speed of the contact breaker. Unfortunately the contact breaker, which was adjustable in its rate of vibration, had reached its. limit of speed, so that a completely new arrangement has now to be employed. On the Electric Resistance of Magnetite. By Professor Sitvanus P. Tuompson, D.Sc. This is a preliminary note on a research begun with the view of elucidating the question whether the conduction exhibited by various mineral ores and metallic oxides and sulphides possessing quasi-metallic conductivity is or is not accompanied by electrolysis. The substance selected, magnetite or magnetic iron ore, is a. thoroughly good conductor, as is evidenced by the simple fact that if a piece of it be interposed in the circuit of an ordinary electric bell the bell can be rung- through it. The sample selected was a fine homogeneous piece of ore from Arkansas, and. was reduced by the lapidary’s wheel to parallelopipedal bar. Its total length was. 5°53 centimetres, its breadth 1:52 centimetre, and its thickness 1:27 centimetre. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 315- The bar was placed between electrodes of platinum foil, which were clamped against its end-faces by means of screws; it was then placed in a bath of paraffin oil, enabling it to be heated to any desired temperature up to 135° C. To test for electrolytic polarisation a current of about 1 ampére was passed through it from three nitric acid cells for some minutes. On stopping the current there appeared a slight polarisation, not, however, exceeding 0:0005 volt, and there- fore of an order indicating a thermo-electric rather than an electro-chemical origin. The specific resistance was then measured by observing the fall of potential between two marked points, 3:22 centimetres apart, upon the bar, and comparing this with the fall of potential between the two ends of a standard resistance coil, intercalated in the same circuit. The resistance was found to diminish very remarkably as the temperature was raised. Observations were made at intervals of from twenty to forty minutes apart, with the following result : Temperature (C.) Resistance of centimetre cube in B.A. units 23° 0-719 54° ‘709 79°5° 505 107° ‘416 153° ‘287 It appears that the resistance of magnetite agrees with that of carbon and electrolytes in possessing a negative temperature coefficient. A somewhat longer and thinner bar of hematite prepared for future experi- ments showed a resistance of about 108 megohms, which in a preliminary heating fell to 81 megohms. The determinations were made by the author's chief assistant, Dr. R. M. Walmsley. On the Conductivity of Mixtures of Aqueous Acid Solutions. By Dr. Svante ArrweEntus of Stockholm. An abstract of a paper to appear in Wiedemann’s ‘ Annalen,’ specially made by the author, and communicated through Oliver Lodge. The translation of the abstract made by W.N. Shaw. 1. Methods employed. Previous authors.—Hitherto only comparatively few experiments on the conductivity of mixtures of electrolytes have been made, by Bouchotte,' Paalzow,? Bender,> and Klein.* These experiments have moreover un to no definite general results, mainly on account of the paucity of experimental ata. My experiments have been made at 25° C. in the chemical laboratory of the Polytechnic at Riga on Kohlrausch’s well-known method, with the use of the. _ telephone. ; 2. Distribution of the water among solutions.—When two electrolytes are dis- solved in the same water two different views of the nature of the solution may be held: either aii the water affects the one electrolyte as well as the other, or the _water divides itself so that only one part of it affects the one electrolyte and only the remainder the other electrolyte. Experiments (by Ostwald) have been made with acetic acid and butyric acid. Normal solutions of these acids have conductivities respectively of 1:478 and 1-020. According to the second view the conductivity of the mixture would be $(1:478+1:020). It was found to be 1:250- (instead of 1:249). According to the first view the mixture would have a conduc- tivity equal to the sum of the conductivities, of acetic acid at half normal strength (1:119), and of butyric acid at half normal strength (0°853); this would give 1 CR. tome Ixii. p. 955, 1864. 2 Poggendorfi’s Annalen, Bd. exxxvi. p. 489, 1869. 3 Wiedemann’s Annalen der Physik und Chemie, Bd. xxii. p. 197, 1884. * Inaug. Diss. Wiirzburg, 1885. 316 REPORT— 1886. the conductivity of the mixture 1:972. Many such experiments were arranged, and all showed the superiority of the second view. All the experiments discussed in this paper also prove the soundness of this view. We shall consequently adopt this second view in what follows. 3. Fundamental formula.—tlf two electrolytes (in dilute aqueous solution) are mixed in the proportion of m:n, and if the conductivity of the one solution be a, and that of the other 6, then the conductivity of the mixture will be a if the solutions suffer no change in the mixing. This formula is the mathematical ex- pression of the idea that the conductivity depends solely upon the number of electrolytic (active) molecules per unit volume, and on the friction of the ions in the solvent. This friction undergoes no appreciable change in very dilute solutions. 4, Consequences of the interchange of water in the mixture of solutions.—When hydrochloric acid solution is diluted, the number of electrolytic molecules increases but very little :1 for the sake of simplicity we may assume that the number does not increase at all. When, however, a solution of acetic acid is diluted, the number of electrolytic molecules is considerably increased (e.g., by dilution to twice the volume, from a standard solution, the increase is in the ratio of 1°51: 1). When therefore solutions of hydrochloric acid and acetic acid are mixed, the conductivity will be greater than the above formula shows, if water is transferred from the hydrochloric acid to the acetic acid solution, and vice versd. In general when solutions of a stronger and a weaker acid are mixed, and the weaker acid takes water from the stronger, the conductivity will be greater than that given by the formula ; and conversely if the stronger acid takes the water of solution from the weaker. A formula for this phenomenon is easily deduced; it shows that if the above consideration is valid the conductivities of the original solutions must not be very widely different; it likewise shows that the greatest deviations from the formula occur when the solutions are mixed in equal quantities. 5. Isohydric solutions.—If a given solution of an acid be mixed in equal volumes with solutions of another (stronger) acid of different degrees of concentration it is found that the above formula is applicable for a certain degree of concentration. For greater concentration negative deviations will be found, and on the other hand for less concentration positive deviations; according to the explanation given above, that solution of the second stronger acid, which possesses the particular degree of concentration, is of such a nature that it neither takes away water from the first solution nor gives any up to it when the two are mixed. On this ground I call two such solutions of different acids relatively sohydric. I have defined the concentrations of the solutions by their conductivities. The experimental method for the determination of the conductivity of isohydric solutions will be most easily explained by means of an example. To find the hydrochloric acid solution which is isohydrie with tartaric acid (75°51).? Under ‘ observed’ is placed the conductivity found, under ‘calculated,’ the conductivity calculated by the formula given. Obs. Cal. Diff. 5 ce. tartaric acid solution (75°51) + 5 ce. hydrochloric acid solution (9462) . 84 49 85:07 — 0:58 5 cc. tartaric acid solution + 5 cc, hydro- chloric acid solution (85°68) : 81°54 80:60 +°78 By interpolation (and allowing’ for error of observation =0°5 p.c.), we get as isohydric with the tartaric acid solution (75:51) the hydrochloric acid solution (89:2 2°9). In a similar manner the numerical values contained in what follows have been obtained. 6. Examination of the view adopted in § 2.—This examination was conducted ’ Le., the molecular conductivity increases very little—I refer always here to dilute solutions. ? By this is understood tartaric acid of conductivity 75°51. The units here em- ployed may be reduced to Kohlrausch’s by multiplication by 10-*. ° ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 317 in two diiferent ways: (a) Solutions which are found to be isohydrie when mixed in equal volumes must also be isohydric when they are mixed in other proportions. This proved to be the case. Phosphoric acid (223:7) and hydrochloric acid 167-4) were mixed in the ratios 3:1, 2:2, and 1:5; oxalic acid (4947) and acetic acid (4°857) in the ratios 10:3, 1:1, and 3:10; tartaric acid (1:566) and hydro- chloric acid (1°757) in the ratios 10:3, 1:1, and 3:10; acetic acid (12:18) and hydrochloric acid (14°54) in the ratios 10:1, 10:2, 10:4, 10:7,1:1, 2:3, 1:2, 1:5, and1:10. Inno case was there a difference between the observed and calcu- lated conductivities which reached the limit of the error of observation (0°5 p.c.), (6) Solutions which are isohydric with any the same solution must also be wohydric with each other. Otherwise, as is easily seen, we might have three solu- tions, among which a permanent current of water would circulate always in the same direction. I have found— A. (a) Phosphoric acid (225-6) isohydric with oxalic acid (139:7 + 7'5). + a “ + » hydrochloric acid (168-8 + 10), (B) Oxalic acid (141:7) = 5 pelea ser) B. (a) Hydrochloric acid (88°59) __,, » tartaric acid (75:00 + 2°5). ss a As i » OxXalic acid (85:07 + 3:5). (8) Tartaric acid (75°39) Fe “5 » »» (82°08 + 3:3). C. (a) Formic acid (5°576) iN i) ah C4901): a ef “A rs » hydrochloric acid (5:309). (B) Oxalic acid (4:915 + 0:17) “i $i A 9» (5'336 + 0°18). It will be seen that the numbers are perfectly satisfactory. 7. Table of tsohydric solutions.—In the following table particulars of isohydric solutions of six acids, as different as possible, are collected ; their conductivities (multiplied by 10%) are given, together with the possible errors. Above the con- ductivities I have put in brackets the number of gramme-molecules per litre of the corresponding solutions. These are calculated from Ostwald’s numbers. Solutions more concentrated than normal ones have not been investigated. Hydrochloric Oxalic acid Phosph oric Tartaric acid | Formie acid Acetic acid acid acid (0°1737) (0°513) 609 + 35 607 (0:0461) (0:0625) (0°337) 168:8410:0 | 139°747°5 225°6 (0°02 38 (0:0331) (0:0764) (0°520) 88°6 + 2:9 85:143°5 82°24 8:2 75:0 (0:00475) (0:00488) (0:00702) (0:0260) (0°1077) (1:000) 17°98 40°46 | 16°27+0°46 | 16:1140-72 | 16-4140°45 | 16:85 40-64 13°81 (0:001402) (0:00135) (0:00163) (0:00324) (001261) (0:0965) 5°336 + 0'134| 4:915 +0°175]| 4:926 + 0-174! 4-903 + 0:146 5°467( + 0°15) 4:855 (0:000349) | (0:000396) (0:000440) (0:000498) (0009175) 1524 + 0:032 |1°582( + 0-05) | 1-479 + 0-057 | 1:499 + 0:20 1476 8. Since obviously any solution of two acids in the same water can always be represented as two isohydric solutions, it follows that when two acid solutions are mixed the two acids divide themselves with reference to the water, so that two tsohydric solutions are formed. From the above table it follows that the specific conductivities of isohydric solutions are approximately equal. 318 REPORT—1886. Further considerations, which cannot here be given, show that if the con- ductivity of a mixture of acids is calculated on the assumption that solutions of equal conductivity are isohydric, the probable error amounts to 1 p.c.; being rather greater if the strengths of the acids are very different, and less if they are nearly equal. 9; Supplementary remarks.—The different bases have also been examined in a perfectly similar manner. The results obtained are strictly analogous, including the equality of the conductivities of isohydric solutions. But the carbonic acid of the air had produced a disturbing effect to such an extent that the numbers are too uncertain for publication. I have also found that acetic acid (1°166) is isohydric with ammonium acetate (0:469). The ratio of the conductivities of the two (2'485: 1) is nearly the same as the ratio of the maximum values of the con- ductivities of acids and salts (2°83:1 according to Kohlrausch). This seems to point to the conclusion that an electrolytic or active molecule of an acid, in water, at ordinary temperature conducts 2:83 times as well as an electrolytic molecule of a salt; and not that in extreme dilution the acids are any more loosely combined (‘disagregirt’) than the salts. This arises probably from a smaller fric- tion of the ion H of the acid (probably also of the OH of the bases) with respect to the water, in which it also occurs as an ion, than occurs with the other ions, This difference might disappear at higher temperatures. From the hypothesis that the different electrolytes divide the water between them, there arise relations which promise to explain some very curious phenomena. If for example a weak acid or base and a neutral salt are dissolved in water, isohydric solutions will be formed in which the weak acid or base will get extremely little water. In consequence, its molecular conductivity, and accordingly the number of active molecules, will be very considerably diminished, I anticipated this on other grounds in my paper of 1884,’ and endeavoured in that way to explain that the weak acids prove to be much weaker on mixing with bases than they are for the same concentration when no other bodies are in the same solution. ‘The same hypothesis may also explain the great depreciation of strength of weak acids when neutral saits are present, as calculated from the rapidity of reactions,? and of the weaker bases in saponification reactions. I am still engaged upon the solution of similar questions. On the Verification of Faraday’s Law of Electrolysis with reference to Silver and Copper. By W. N. Suaw, M.A. Since the time of Faraday his law of electrolysis has not been subjected to any very extensive experimental investigations. A summary of the results obtained is given in the article on Electrolysis in the ‘Encyclopedia Britannica.’ The most accurate verification appears to have been conducted by Soret, who attributes to the law an accuracy of 0-2 per cent. for copper and silver. Buff used different currents and found the law verified by experiment to about | per cent., but the general im- pression has been that the law was only true to a somewhat rough approximation. A practical acquaintance with the behaviour of an electrolytic cell of copper sulphate shows that it is not necessary to attribute the defect from the theoretical value of the chemica! equivalent obtained in that way to the failure of Faraday’s law. In depositing copper upon a copper plate it may often be observed that small but brilliant red crystals are formed on the deposit. These crystals under the microscope are very beautiful; they may probably be regarded ‘as a suboxide of «copper formed by the action of the copper on the solution. A purple coloration is, moreover, often formed on the cathode, and this is possibly due to the presence of the same compound of copper. This secondary action produces, of course, a differ- ence in the weight of the deposit formed, and the true amount of electricity which has passed cannot be inferred either from the weight of the copper with the compound or from the weight of copper remaining when the crystals have been removed. 1 So Sea) il 024 | 1029» 1008 962 865 695 398 a LiCl Bre a SFR. SN) MMOS 943 921 875 775 591 303 | 106 4BaCl, : . «| 1142 | 1126 | 1092 | 1006 861 658 = sa Randle. ge | 1086) |) 1029. 994 915 768 514 180 60 SCUBA)! teesy | ve) ail 207 || 2296 ~|) 1208.) oadel | ade9 968 770 a KNO, as oeealelolone ) 1207 «|, 1180.) s1198 983 | -752 = a NaNO, Se ig mse ile ts 975 952 907 817 617 = aa AgNO, See en eTUSONN | o1078) 1 0ss Oo Ne0IT 886 635 351 as $Ba2NO, Shite ac teeelts| ail aha 096" 9 nL O62: 951 755 = a ne KCIO, Se ee eth ote 22°” Aton. || 21058 927 = a = KC,H,0, eens ie SSS 934 919 879 784 594 240 30 NEE 7 1275 | 1249 | 1207 | 1098 897 672 = ee EESOME gas a) Sai} OBS 1084 998 906 734 415 8 re EMCO ay s. , «| C929 945 906 818 637 386 ws es dMgsO, . . . . «| 1056 | 1034 935 715 474 270 82 2s 4ZnS0, oO SE ae Fe | TOGO P1023 919 685 431 249 82 ay BomSOrene 5 ce Ce. | 086) || 1062 950 675 424 241 aS = HO). . « « «| 1954 | 3171 | 3455 | 3416 | 3244 | 9780 | 1490 | 600 HNO, . . «| 1144 | 3088 | 3427 | 3395 | 3225 | 9770 | 1470 | 610 4H,S0, . . . . .| 1413 | 3118 | 3316 | 2855 | 2084 | 1890 | 1970 | 660 KOH i Alaa 747 | 1689 | 2110 | 2124 | 1986 | 1718 990 | 423 eens ss |, 885 995 | 1221 | 1083 879 660 403 | 169 ECO. ., + « «| 69% a S74 | 1087 899 682 427 = 2 EEO aril .oifhad. Latow hn 409 837 968 -| 790 430 200 160 | 148 NaOH Fc ited acl C130) n 1070" |" 1810» | 1870, 170.0100 652 | 190 C,H,0, Py TE a). Aedasea lesen! 995 380 132 43 12 | 26 5 I ti. ca Dailallt. 1560 610 260 92 31 84 24 5 338 REPORT—1886. The next little table contains the estimated limiting values of molecular con- ductivity for infinite dilution. First for fairly neutral substances, next for acid and alkaline bodies. The ionic velocities corresponding to these numbers are, for the first set, between ‘0014 and ‘0010, and for the second set between 0040 and ‘0013 centimetre per second, rate of travel of anions past cations, when urged by a slope of potential of 1 volt per centimetre. Limiting Values of Specific Molecular Conductivity for extreme dilution, (A). ORDINARY SALTS. 3K,80, 128 x 10-7 iMgSO, 108 x 1077 i i ener i7n80, | 1Dathey KCl i iNa,SO, 106 Am(Cl 121 m 4ZnCl, 104 55 KNO, Tapa. NaCl 108°, TRAC Alsat + 5, NaNO, O5. Yili KCIO LBP 95 ALAS iis, One Ba NO y idles 5, LiCl 96.43 og ROMEO AION: &5 KO,H.0,./; cues AgNO, 109 i$ ‘ These values are all of the same order of magnitude, but they are by no means equal to one another.’ (B). NON-NEUTRAL BODIES. $H,80, 370 x 1077 KOH 220 x 107 HCl Soy NaOH 300° HNO, B00 vas, reco. Sag eae EO; 110. >, iNa,CO, © 120 ,, Law oF Speciric Iontc Vetocrry. Taking into account the results of Hittorf on migration, Kohlrausch estimates as the relative velocities for the following ions in a solution of strength defined by m ="1:— VK Am Na Li Ag H Ba 3Mg 3Zn 52 50 32 24 42 272 30 26 24 Cl it NO, CIOS | CaEO; OH 54 55 48 42 26 143 and with these numbers he proceeds to calculate the conductivity of solutions of this strength (m=-1) of the various substances, and to compare them with experi- ment.' The agreement between observed and calculated numbers for a large num- ber of substances as regards both conductivity and migration is remarkable. For instance, here are some calculated numbers to be compared with the column headed ‘1 of the table just quoted, page 337. KClis:| an, bem sGeU AgNO; 0. >.> aele AmG), . |. 1040 }Ea,NO,,-... i+ HaneeO Wallon Denar’ Sep KOIG,. “254: 1p ene TiGh. 2 phiete} cam 760 ROMO) 0, tte PRAM ek che! ike a B40. HOM... te. > 70 -ha tee tictaee wTR0 HNO,; |. i. See Kies 1 works oiste LO7€ KOH: ik. +. +. KNOG, , “io ake 1000 NaOH . . 1760 NaNO, joost [hs 800 But several substances remain intractable. For instance, acetic acid gives, calculated, 2980 ; observed, 43. 1 See table on page 215 of Kohlrausch’s memoir. 4 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 339 The following remarks are taken from a criticism of the above abstracted memoir of Professor Kohlrausch, published by M. E. Bouty in the ‘Journal de Physique,’ for September 1886. (Translated by Mr. Love.) ‘The object of M. Kohlrausch is to control the results of the experiments of Messrs. Lenz, Ostwald, and Vincenti, and my experiments of 1884, and to throw light on points left in dispute. To this end he works by the methods which he had previously pointed out, but with excessive dilutions, attaining to 0:00001 gramme equivalents per litre. These liquids conduct scarcely better than distilled water, and a thousand times worse than the water supplied to the town of Wiirzburg. Experiments of this kind raise a multitude of theoretical and practical difficulties which M. Kohlrausch points out in all good faith, if he has not always given them a decisive solution. ‘Tn the first place come the difficulties due to the employment of alternating currents and the telephone. ... Possibly graver difficulties arise from the employment of distilled water; and these will always present themselyes, what- ever method be employed, if the dilution be pushed to extreme limits. In the first place, it is very difficult to procure distilled water of constant composition. M. Kohlrausch used rain-water distilled in a tin retort with a silver condenser, and stored in large glass flasks. The conductivity of this water ranged from 1:1 to 15 x 10-" (the conductivity of mercury being taken as unity), and was diminished rather than increased after keeping in the flasks, ‘Let us admit this conductivity as accurately known. If a trace of saline matter be added to the water its conductivity increases. M. Kohlrausch supposes that the conductivity of the salt and that of the water simply add; and as this rule if applied to neutral salts assigns to them a molecular conductivity sensibly con- stant in very dilute solution he supposes it to be sufficiently justified by experiment. M. Kohlrausch admits, however, that the greater part of the conductivity attri- buted to the distilled water really belongs to foreign matter—neutral salts, acids, -or bases—with which it is contaminated ; if some saline particles be added to this water we then have to deal with a mixture of which we know only a single element— that which has been added—the nature and proportion of the other elements remain- ing unknown; it is possible that the conductivity we wish to measure may be modified by the presence of this unknown element in a manner altogether arbitrary, and which may vary from one salt to another... . ‘M. Kohlrausch does not admit the division of neutral salts into “normal” and “abnormal,” which I established on the basis of the inequality of the numbers relating to the transport of the ions. If we consider only anhydrous normal salts, the limiting values assigned by M. Kohlrausch are as follows :— NH,Cl %/m‘10° = 1205 KC10, %/m108 = 1141 Bilal tet 1.1016 KI i 1207 KANO, oie sgl! | ABEB AgNO, ,, 1080 AR BO is btgub vn 2B ‘M. Kohlrausch thinks himself in a position to ‘enunciate the following con- clusions :— ‘1. For a given neutral salt the molecular conductivity tends towards a definite Limit, as the dilution is increased indefinitely. ‘2. For the different neutral salts this number is always of the same order of magnitude. ‘The extreme values of k/m ‘10’ are 128 for K,SO,, and 94 for KC,H,0, {an abnormal salt), ‘3. This limiting value depends on both ions: they group themselves in the order of diminishing conductivity in the manner indicated by the following table :— Kation Anion Potassium. Sulphuric Acid, Ammonium. Iodine. Barium. Chlorine, Silver. Nitric Acid. Z2 340 REPORT—1886. Kation Anion Copper. Chlorie Acid. Magnesium. Acetic Acid. Zine. Sodium. Lithium. ... ‘According to M. Lenz, the kation alone would influence the conductivity in dilute solution, a statement which M. Kohlrausch refuses to accept. ‘4.° With increasing concentration the molecular conductivity always diminishes, and to a very unequal degree for different salts. In order to exhibit this variation conveniently to the eye, M. Kohlransch constructed curves, taking as abscisse the values of m!, and as ordinates the molecular conductivities. These different curves present markedly different courses, but I observe that they all approach more or less. to a common ordinate for m=0.! This peculiarity is especially well marked in the case of the normal salts if we reject the portion of the curve, often a little inflected, beyond m=0:006 ; 7.e., if we produce as near as can be judged (de sentiment) the sensibly rectilinear portion which precedes this. ‘5, For the salts of the monobasic acids the molecular conductivity in dilute: solution ts represented approximately by the formula klm= A—Bm', expressing that this conductivity differs from a constant value A by a term inversely” proportional to the mean distance of the molecules of the salt. My latest researches * have led me to an analogous result. ‘The limiting value of the conductivity of sulphuric, hydrochloric, and nitric acids is sensibly three times that of neutral normal salts, as I had previously pointed out. Sulphuric acid, moreover, exhibits peculiarities which would alone require a. monograph. ‘ Coming to the interpretation of the capital fact of the increase in the mole-- cular conductivity of all salts in dilute solutions, M. Kohlrausch thinks that it must * be attributed to a special conductivity acquired by the water when it contains other substances in solution, but which is too small to be evident in strong solutions. Very small quantities of foreign matter may communicate to the water that state of dissociation which Clausius looks upon as the origin of the migration of the ions under the influence of electric forces, and hence a considerable portion of the current might be diverted through the mass of the water, which would itself then share in the electrolysis. This hypothesis, to which M. Kohlrausch declines to. give greater precision, may be interpreted as a denial of the very principle which he applies to the calculation of molecular conductivity, as in order to obtain this he had already subtracted from the gross conductivity that part which belongs to the distilled water, more or less impure, and therefore already possessing the special con- ductivity with which he deals; unless this be capable of changing with the nature- and proportion of the salt in solution, which implies the formation of hydrates, and that the conductivity of a solution is not equal to the sum of the separate conduc-- tivities of the salt and the solvent, the calculated numbers on which the discussion hinges would in that case lose all definite meaning.’ 1[I should imagine an examination of the curves is all that is needed to refute this. criticism: compare the curves for KNO,, }BaNO,, NaNO,.—H. F. J. L.] 2 Comptes Rendus de V Académie des Sciences, t. cii. p. 1375. 3 [Kohlrausch gives another possible interpretation of the rapid diminution of the- conductivity of salts of polyvalent radicles as concentration increases, viz.—that in extremely dilute solutions the more complete dissociation tends to assimilate such compounds in behaviour to those of monovalent radicles: ‘ein anderer Aggregations~ zustand, etwa*eine gréssere Dissociation in dusserster Verdiinnung, welche die: mehrwerthigen ‘ihnlicher macht.’—H. F. J. L.] ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 341 Professor Koutravsce has favoured the Committee with the following letter (in English) addressed to the Editor. Wiirzburg, January 6, 1887. My prar CoLteacun,—You have had the kindness to send me a proof of part of the Report on Electrolysis before finally going to press, and I must take advan- tage of your friendly permission to express my own views on the subject. Since I consider it of great importance not to be misjudged in the reports of so prominent a body as the British Association, I cannot avoid making a personal remark. M. Bouty writes that the aim of my last published memoir was ‘ to control the results of the experiments of Messrs. Lenz, Ostwald, Vincentini and my (Bouty’s) experiments of 1884.’! M. Bouty is mistaken, certainly with all good jntention, as to the course of my research. I already in 1874 carried on a series of experiments with diluted solutions. Allow me to give, as a proof of the perfect independence of my research, a series of observations on sulphuric acid, made on January 30, 1875. Per cent. H,SO, p= 5°05 1:03 339 +0992 +0324 -0098 -00306 ‘00099 Conductivity at 18° kl0®=1985 443 1645 55:1 2045 677 2:06 0:57 108*/,= 893 480 479 556 681 690 673 580 Nitric acid (February, 1875) Per cent. HNO, p= 6°32 2:05 °512 +100 ‘0152 Conductivity at 18° kl0®=2970 1045 275 55:3 8:65 108*/,= 470 510 537 558 570 These numbers have been written for more than ten years in my books. The same give, when calculated in reference to the molecular number m :— Sulphuric acid m=1:06 0-212 0:0698 0:0202 0:00661 *00200 :000623 +000202 106*/,= 187 209 2388 2738 309 340 331 =. 280 Nitric acid m=104 0328 00813 00159 0:0024 108 */n = 286 319 338 352 360 The molecular conductivity */m of the sulphuric acid increases very rapidly by greater dilution, and very nearly reaches that of nitric acid. Extreme dilution causes again a decrease. This is the chief part of that research; it was published nine years later by Ostwald and then by me. T discontinued these observations at that time, partly for the very reason that they gave such new results. The initial increase of */, for sulphuric acid, and the final decrease, made me suspicious; besides, the observations at that time were ‘connected with difficulties, inasmuch as I could not so easily measure great ‘resistances; also I could not obtain very pure water. At best the new object demanded a thorough research, which would draw me too far from my chief object. Tf one is working in an entirely new field he ought not to spend too much time on “particulars.” That dilute solutions are of very great interest has been emphasised in the first memoir by Grotrian and myself (1874), and later often enough in my publications. Indeed I limited myself then to combining those relations equally from the results which alone at that time were at my disposal, 7.c. solutions of moderate dilution. 1 p. 339. 2 In order to protect myself against the reproach of a too one-sided investigation, I would further remark that I early informed myself concerning mixtures of salts as well as acids in aqueous solutions, also concerning salts in alcoholic solutions, and ‘finally, concerning mixtures of water and alcohol, many years before. After the publication of detailed researches of other authors I ceased to continue these inves- tigations, 342 REPORT—1886. That this was no final solution of the problem I knew at once, and said so, And as- soon as I had concluded with the stronger solutions at a time when of all other observations only those of Lenz were at hand, [ recommenced with strongly dilute solutions. The specific difficulties of these experiments, the striving after accuracy and desiring to give absolute values, retarded the conclusion. But all my doubts, e.g., as to whether sulphuric acid in great dilution did not conduct exactly like the monobasic mineral acids, were perfectly removed before any publication on the subject. These remarks are only caused by the wish that a research to which I have given years may not be regarded finally as a mere repetition of someone else’s work, My repulsion against publishing observations which I considered were open to im- provement, was the cause of other investigators’ earlier publications, they thereby gaining in many things the publisher’s priority. On the other hand I can consider my research as of a greater experimental precision, and that you expressly recog- nise this for the later publication perfectly satisfies me. M. Bouty reiterates his objections to my method of measuring resistances with alternating currents.1 The empiric ground of this objection has been referred by me, and by you also, to an erroneous formula which M. Bouty used. The difficulties which Messrs. Bouty and Foussereau yet find will surely be overcome if these gentlemen will go through the same experiments which I ‘at some length’ described in my last treatise. M. Bouty’s regret, that the water for solutions could not be obtained absolutely pure, must, of course, remain; but the same diffi- culty occurs in all observations of others addressed to the same object, and in most of them to a much higher degree than in mine. If the water which J used for solutions does not suffice for the explanation of the phenomena of dilute solutions, then this explanation is so far entirely unknown. I am also in this case obliged to you that you have emphasised my carefulness in this direction. M. Bouty says: ‘ Let us admit this conductivity as accurately known.’ I measured the conductivity of the water every time shortly before the series of observations ; those observations in which the characteristics of the solvent came into account at all were then made within a quarter of an hour. The telephonic method of measurement is so specially valuable on account of its very rapidity. That the conductivity of the solvent water must be subtracted from the conductivity of the solution, I have (for neutral salts) shown as probably very nearly correct. At present also I do not know how an observer could do otherwise. Finally, even an inaccuracy from this cause could only affect the most dilute of my solutions noticeably ; considering the degree of dilution with which the other memoirs have to do, I cannot at all allow a possible inaccuracy proceeding from water in my observations. Of course M. Bouty is correct in considering the use of quite pure (non-con- ducting) water as necessary, in order to explain with perfectly conclusive proof the relations obtaining in extreme dilutions. To consider his ‘law of equivalents ’ thus far as an aztom cannot be denied him. Experience, however, in all observa- tions (his own among them) disagrees with it, and I cannot see the necessity nor the probability of this axiom. It is indeed remarkable that the great differences of conductivity of strong solutions in the case of all salts reduce to about 30 per cent. Grotrian and I twelve years ago found this law, which is true for salts of monovalent acids even in moderate dilution, for the chlorides of the light metals. Lenz proved the same thing in a more general form, making use of more extreme dilutions. It is to the credit of Bouty that he set aside the yet remaining excep- tions. It would certainly be heartily welcomed by every physicist if finally the equality of all molecular conductivities in extreme dilution should be proved. With Arrhenius one could then place this law alongside of the Boyle-Marriotte’s law. I myself, since I first introduced the conception of the ‘molecular conductivity,’ would have an especial motive in agreeing to such a striking meaning of this. conception. At times, however (as you yourself mention) the law, at common temperatures, does not agree with known facts. Hight years ago I announced the following relation :—‘ The better a substance 1 pp. 339, 354, 356, 384. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 343 conducts, the slower usually does its conductivity increase with temperature ; in other words: ‘the differences of conductivity of different substances usually diminish at higher temperatures.'! The supposition expressed by Arrbenius, that at high temperatures dilute solutions conduct equally well, does not lie beyond the bounds of possibility, but is at present only a hypothesis. For common temperatures the law which I derived from Hittorf’s numbers for migration of ions in connection with my observations in conductivity, which were independent of this migration, appears to me to contain a simple and natural hypothesis which has proved true for substances with monobasic acids. One must be blind to explain as an accident the systematic ordering of things under this view. Now, just a remark concerning some things by Arrhenius, who through the introduction and consequent treatment of the conception of ‘activity ’in connection with Clausius’s theory, has given us so important a point of view that his meaning must be carefully considered ; especially do I regard as a decided advance the light which has been thrown by his and Ostwald’s memoirs upon a hitherto theoretically dark group of bodies, viz., the bodies called by me, ‘ conductors of the lower order.’ I should, however, raise several objections to Arrhenius’s radical meaning, that the theory which accepts a connection between internal friction and electrical con- ductivity ought to be rejected.? It appears to be a postulate @ prior? that besides activity some kind of friction must necessarily be accepted ; through the work of Wiedemann and others, it has long been known that usually a lesser conductivity is connected with a greater internal friction. One cannot deny the nearly quanti- tative connection between the influence of temperature upon the so-called ‘ fluidity,’ and upon conductivity, as shown by Grotrian. The proof which I gave,’ that the supposition of a mechanical and electrolytic frictional resistance of about equal amount, allows the finding of an absolute size of molecules, which approaches the sizes found, by other methods, by Maxwell, Sir W. Thomson, van der Waals and others, seems to me of no little interest. In fact, the surprising phenomena in gela- tinous substances* and ‘solid’ electrolytes must be supplemented by an accurate definition of the idea ‘internal friction’ before one can come to the conclusion that electrical resistance and internal friction are totally distinct. Since, however, M. Arrhenius tells me that he intends to explain his remarks for himself,> I shall not enter into detail. But I must draw your attention to something else. The supposition which Arrhenius makes in reference to the dissociation of solutions of MgSO, and related substances,® is really one special case of the possibility, expressed by me, that water, in extreme dilutions, can take part in the conduction. I have expressly left it an open question whether such aco-operation should consist in the formation of a hy- drate. The hypothesis of Arrhenius is such a possible case. Should this be true, the possibility would thereby be strengthened that the rapid rise of the molecular conductivity of many salts, in extreme dilution, may be referred to a sort of second- ary cause; MgSO, in solution conducts so much worse than H,SO,, and possibly also than MgO,H,, that a dissociation of the salt into these substances, even when only a small quantity of the decomposed substance is found, may cause the conductivity to increase considerably. M. Bouty’s fear’ that by this means ‘the calculated numbers on which the discussion hinges would in that case lose all definite meaning,’ is a little strained. To my idea such an influence of the water, if it exists, comes only noticeably into consideration in extremely dilute solutions, and in this case perhaps also only in a limited group of compounds. I conclude this letter assuring you of my real satisfaction that you, my dear colleague, have given the impulse to collect the newer results on electrolysis. My own conclusions, drawn from phenomena made known to me, did not dare to wander far from matters of fact, knowing myself to be not sufficiently well 1 Wiedemann, Ann. VI. 196. 1879. 5) OOS ? pp. 344 and 348. Aon. alle 3 Wiedemann, Ann. VI. p. 207. 1879. 7 p. 340. 4p, 347. 344 REPORT—1886. infornied in theoretical chemistry. My old wish, that chemistry might make the interesting results of electrical conductivity of service for its theoretical purposes, has been realised in the recent memoirs of trained and clever chemists. Your own work and the present report, supported by the authority of the British Association, will, I am sure, bring forth other fruits in the field of electro-chemical theory. Yours very truly, F, Kourravscu, Contribution to our Knowledge of the Action of Fluidity on the Conductivity of Electrolytes (Behaviour of Jelly). By Svante Arruentus. Trans- lated from ‘Kongl. Vetenskaps-Akademiens Fordhandlingar,’ 1885, No. 6, Stockholm, by Professor W. Ramsay. From numerous researches of physicists! it has been held as proved that resistance to the passage of an electric current undergoes the same variations as the internal friction, z.e. that both increase or decrease simultaneously. This view is based on a considerable number of data regarding the conductivity of salts in aqueous solution. To obtain further knowledge on the subject it was necessary to test the action of solvents other than water. This has been done by C. Stephan,? who in- vestigated the behaviour of alcoholic solutions, and found only an analogy between electric resistance and internal friction, but not complete proportionality ; and this has been confirmed by other observers. That proportionality exists, except in some exceptional cases considered by Stephan,‘ cannot be held. Unfortunately Stephan has only investigated alcoholic solutions containing from 0 to 70 per cent. of alcohol, z.e. those of which the internal friction is greater than that of water. Had he investigated solutions richer in alcohol, he would doubtless have found that an alcoholic solution of a salt has less conductivity than the corresponding more aqueous solution, in spite of the former having less internal friction than the latter. This has been clearly proved by Hittorf’s work,’ and has been completely con- firmed by Lenz’s ® investigations, although Lenz’s work was not directed to that point. I subsequently found on conversing with Professor Ostwald, of Riga, that he, like myself, dishelieved in any connection between internal friction and resist- ance, and he proposed that I should undertake the investigation of which an account follows. From a paper by H.de Vries’ it follows further that the rate of diffusion of a solution of salt is nearly independent of internal friction; a result which Graham’s experiments had already indicated. Lastly, Long’s ® work shows that the rate of diffusion of an aqueous solution of a salt is nearly proportional to its conductivity, whence it follows with high probability that the resistance must be nearly independent of internal friction under similar conditions. And should this prove to be true, the whole of our knowledge of the process of electrolysis would be much simplified. The method of investigation was that proposed by Kohlrausch and Nippoldt.® The resistance-vessels were of the same form as those I previously used. The platinised platinum terminals were 15°5 mm. apart, the diameter of each was 256 mm., and through each passed a glass tube 9 mm. in diameter. The solutions investigated were solutions of sodium chloride, zinc sulphate, and copper acetate, in 1 Among others G. Wiedemann; a detailed description of the work of others is to be found in his E/ectricity. 2 Wiedemann’s Annalen, 1882, xvii. p. 673. $ . Wiedemann has proved this to be the case with solutions in glycerine (Wie- demann’s Annalen, 1883, p. 20. * Stephan’s figures do not exhibit this proportionality. The ratio is not a constant one. 5 Poggendorft’s Annalen, 1859, cvi. p. 554. & Mém. Acad. Imp. St. Pétersbourg, séx. 7, p. 30, No. 9. * Beiblatter, 1885, p. 160. 8 Wiedemann’s Annailen, ix. p. 623. ® Poggendorft’s Annalen, cxxxvili. pp. 280 and 370. j ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 345 pure water, and also in water in which had been dissolved 4:2 per cent. of commer- cial gelatine. The proportions taken were: (a) 20 cc. of the salt solution diluted to 25 ce. with water; (6) 20 cc. of solution, in which 1:05 gram gelatine was dissolved, diluted to 25 cc. The gelatine solutions were tolerably fluid at 30°, at 25° very thick and syrupy, at 24° the traces of fluidity were extremely small, and at 23°5° the whole had jellied. The internal friction was determined by Sprung’s! method for the gelatine solu- tion containing 4:2 per cent. of gelatine, and was found to be, at 30°5° C., 2-271; at 27-7° C., 2'889, the internal friction of water at O° being taken as unity. At 24° the internal friction was infinitely great, z.e., the solution had gelatinised and blocked the capillary tube. At corresponding temperatures the internal friction of water is, at 30°5°, 0°4475 ; at 27:7°, 04547; and at 24°,0°5171. The internal fric- tion oe the weak salt solutions employed can have differed but very little from these numbers. The distilled water showed a resistance of 60,000 ohms, while the gelatine solu- tion averaged 300 ohms. It was therefore considered unnecessary to introduce a correction for the conductivity of the distilled water present. Now as it is known that all organic substances which do not possess well-marked acid, basic, or salt- like properties have extremely small conductivity, it may be concluded that gelatine also, if free from salts, should manifest great resistance, and the high conductivity of the gelatine is evidently due to the salts which it contains. Conductivity of Gelatine Solution. t ™m l At Al 14:5° 289°8 84:51 2°3 2°03 16°8 273°7 36°54 1:0 0:94 17'8 266°8 37°48 2:3 2°41 20'1 250°7 39°89 ; 1:2 0:99 21:3 244°6 40°88 1:0 0°96 22°3 239°0 41°84 0:9 10°89 23:2 234-0 42°73 0°8 0:96 24:0 228°9 43°69 0-9 0:97 24:9 223°9 44°66 11 1:04 26:0 218°8 45°70 11 1:10 271 213°7 46°80 eT 1:12 28:2 208°7 47:92 11 1:20 29°3 203°6 49°12 11 1:26 30°4 198°5 50°38 2°2 2:7 32°6 188°4 53:08 0:8 1:48 33°4 183°3 54°56 ce a a a es Sa ? Poggendorff’s Annalen, clix. p. 1. 346 REPORT—1886. The gelatine solution was warmed in a water-bath to 35°C. Simultaneous measurements were made of temperature and resistance. As the water cooled the former fell, while the latter slowly rose. The preceding table shows in the first column the observed temperatures, and in the second the resistance in British Association units. From these data the conduc- tivity was calculatedin arbitrary units (according to the formula 7 = — m being the resistance given in the second column); the values of / are given in column three, The fourth and fifth columns exhibit the differences of the temperatures and the conductivities. The results with the gelatine solutions to which salt had been added are given below :— Gelatine Solution with Sodium Chloride. t m Ll At Al 15°3° 43°6 194:°1 51 23°4 20°4 38'8 217°5 4-4 23°6 24'8 350 241°1 3:4 re 28:2 32°6 258°2 ; 4:2 22°3 32°4 30°0 280°5 Gelatine Solution with Zine Sulphate. t m l | At Al 140° 61-6 128°3 | 3-9 12-4 17°9 561 140°7 38 8-2 21-7 525 148-9 43 168 26-0 473 165:7 40 143 30:0 43:5 180-0 15 83 315 41-7 188:3 Gelatine Solution with Copper Acetate. t m l At Al 15:0° 62-0 126°3 41 115 19°1 56°6 137°8 3:0 9°2 22°1 53°0 147:0 3°5 11:8 25°6 49-0 158°8 4-4 13-5 30:0 45:0 172°3 2°6 12:7 32-6 42-0 1850 et, ' y 7 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 347 Here it is evident that the conductivity alters only uniformly with temperature, for had this been otherwise great variations in the neighbourhood of 24° should have been noticeable, for the internal friction increases about that temperature from a moderate value to an infinitely great one. But no sign of such a sudden variation can be deduced from the above figures. The calculated values of the coefficient of temperature are, for gelatine solutions Gelatine alone Sodium chloride Zinc sulphate Copper acetate 0:0281 00244 0:0243 0:0248 and for aqueous solutions 0:0238 0:0234 0:0213 Those for gelatine solutions are generally somewhat higher than for the corresponding aqueous solutions, but the difference is unimportant. If it be assumed that the coefficients of temperature for internal friction and conductivity are the same with aqueous solutions, it cannot be so with gelatine solutions, because for these the temperature-coefficient of internal friction must be infinity, while the conductivity-coefficient never exceeds 0:03. If the conductivity of pure aqueous solutions at 17°8°, which are very mobile, be compared with that of gelatine solu- tions of 4:2 per cent. containing the same amount of salts, which are solid at 24°, the following table results :— Sodium chloride Zine sulphate Copper acetate Aqueous solution. : 250°6 169°6 159°9 Gelatine solution . : 205°6 140°3 134°2 Difference . 5 5 ; 17°9 per cent. 17°3 per cent. 16:1 per cent. The gelatine solution has accordingly about 17 per cent. less conductivity than the corresponding aqueous solution. The found difference of 17 per cent. is not of the magnitude which might be expected if internal friction had really the effect usually attributed to it. Let us now examine the reasons for assuming parallelism between internal friction and conductivity. In most cases the molecular conductivity in aqueous solutions decreases with increase of concentration, and similarly with the fluidity. These relations hold with few exceptions for aqueous solutions, and it is therefore not remarkable that the fluidity and the molecular conductivity of aqueous solutions should vary at about the same rate. But it does not follow that they are interdependent or to be ascribed to the same cause. If very dilute solutions be employed the fluidity remains nearly constant, but the molecular conductivity of salts increases considerably with dilution, as I have shown in my former work, and my results have been confirmed by Kohlrausch.! There cannot therefore be a complete parallelism between fluidity and conduc- tivity in aqueous solutions. For very dilute solutions our present views of the nature of electrolysis lead us to conclude that the variation in conductivity is dependent on chemical change, such as the breaking down of complex molecules, the union of molecules of salt with molecules of water, and so on. And the difference between dilute and concentrated solutions is merely a relative one. We cannot draw any definite line between bodies in dilute and in concentrated solution. Thus strong acids in concentrated solution pass through precisely the same phases as weak acids in dilute solution. There is the same relation between alkali salts on the one hand and mercury salts on the other. The conclusion fol- lows therefore that the molecular conductivity depends chiefly on chemical rela- tions. And there appears no reason to connect internal friction with molecular changes of a chemical nature. A similar relation holds between the temperature-coefficient for fluidity and the conductivity. These are for dilute solutions approximately comparable, and it Gottinger Nachrichten, February 25, 1885. 348 REPORT—1 886. might be expected that in extremely dilute solutions they should coincide. I have shown! that such a relation does not hold either for aqueous or alcoholic solutions. Bouty * who found complete correspondence between these two quantities, was misled by a coincidence in calculating his results, as Kohlrausch has shown.® As all known cases can therefore be explained without assuming a connection between internal friction and conductivity, this theory, which serves only to com- plicate matters, must be abandoned. As a final proof of the justice of the above conclusion I made a cell like an ordinary Daniell, but introduced gelatine into the solutions of zinc sulphate and copper sulphate. The resistance was 1°5 ohm, while that of a similar Daniell’s cell was 13 ohm. But the resistance of the cell containing gelatine gradually increased after four days, owing to bubbles being deposited in the gelatine near the zinc and the copper.* Sur la Polarisation des Electrodes et sur la Conductibilité des Liquides. Par M. E. Booty.’ Abstract by Oliver Lodge. The author first describes Lippmann’s method of measuring the resistance of electrolytes, viz. by tapping offand measuring the fall of potential between two points of the liquid contained in a cylindrical tube, and comparing this with the fall ina known length of wire included in the same battery circuit as the liquid. He proceeds to use it also for determining the polarisation of either electrode, by measuring the potential difference between one of the main electrodes supplying current to the liquid and one of the tapping electrodes ; using the obvious relation e=rC+p in order to find p, the polarisation. With platinum electrodes and acidulated water he thus reckons that with a current of average intensity about 8x 10™° ampéres per square centimetre, the polarisation of the electrode rises as follows :— Polarisation of the cathode is | Polarisation of the anode is In 5 minutes ‘056 volt 103 volt » 40 9 063, 166 ,, ” 60 ” 065 ” "175 ” He then applies a slightly stronger current, but as it is very variable I do not see that the numerical results obtained are very useful. However, the idea is that the polarisation of the cathode attains a maximum and begins even to diminish, while that of the anode goes on increasing. He then measures the resistance of acid water in a long siphon tube, and con- siders that it is independent of current intensity, and asserts, ‘A liquid has only a single way of conducting electricity, whatever may be going on at the electrodes. The expressions ‘‘metallic conductivity” and “ electrolytic conductivity” ought to disappear from science.’ ELECTROLYSIS OF MrIxtTuREs. A number of mixed salts are tried, one of them being always a salt of copper. Results are given for the electrolysis with copper electrodes of a mixture of sulphate of copper and sulphate of zinc, saturated in the cold, and are analysed thus: ‘ For current intensities from 5 to 12 ten-thousandths of an ampére per square centimetre the polarisation of the anode is constant and equal to ‘0088 volt; but that of the cathode varies enormously. For an intensity 29 (ten-thousandths of an ampére as before) it is already ‘02 volt; it increases slowly with the current and is sensibly 1 Bihang till K. V. Akad. Handi. viii. No. 13, p. 45 (1884). 2 Compt. Rend. February 11, 1884. 3 Gottinger Nachrichten, 1885, p. 86. 4 For remarks on this paper see Prof. Kohlrausch’s letter on page 343. 5 Journal de Physique, 1882, 2e série, t. i. p. 346. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 349 constant for the same current when prolonged. But at an intensity 8-6 a new phenomenon is produced : polarisation increases with time, first very slowly, then more and more rapidly, going from ‘04 to ‘65 volt; at the same time one notices that the metallic and brilliant deposit of pure copper which one had hitherto obtained is displaced by a ruddy and non-adhesive deposit. In proportion as it is produced the polarisation increases, and the deposit overspreads the electrode with increasing rapidity. ‘Finally, augmenting the current still more, the deposit passes gradually from red to black, while polarisation increases in a continuous manner, and for a sufficient current-intensity the deposit acquires anew a certain adherence. It is then dark- grey, very rich in zine, and recalls by its aspect deposits of zine obtained from impure commercial sulphate of zinc. ‘ As for the conductinity of the liquid it remains constant all the time, in spite of the variety of electrolytic actions, to which a study of polarisation and aspect of deposit bear witness. . . . The same Aind of thing happens with other propor- tions of CuSO, and ZnSO,. ; ‘One may remark further that the specific resistance of the liquid passes through a minimum for a certain composition of the mixture; it is then inferior to the resistance of even a saturated solution of one of the two salts, and @ fortzor? to that of the same salt diluted down to the strength in which it occurs in the liquor. So the molecules of two mixed salts take part in the transport of electricity, even when only one of the two metals is deposited on the cathode.’ All the variations of polarisation in the above case are then simply and naturally explained by the fact of exhaustion, in the liquid near cathode, of the salt of the metal being deposited, except in so far as diffusion replenishes it. With strong currents it is therefore plainly necessary for zinc to be deposited as well as copper, and it is equally obvious that this zine will tend to clear itself off again by local action. The author then goes on to observe that very similar complications occur even when only one salt is intended to be present. Thus pure CuSO, almost always contains a trace of acid, and accordingly, in its solution, hydrogen plays much the same part as zinc has done in the above described experiment. For feeble in- tensities copper alone is deposited, but for stronger currents the deposit is red and contains some oxide [?]. Hydrogenised copper forms with copper, in fact, local couples in which copper is the attacked element. Evolution of heat by local action has been proved by the use of thermometer electrodes, Even if CuSO, contained no acid to start with, it would soon get some by electrolysis ;1 for the solution of anode is never exactly equal to deposit on cathode, In all these cases one may notice that electrolytic reactions which go on for the most feeble currents absorb always less heat than those which occur with stronger currents. This extension to mixtures of the beautiful law announced by Berthelot for the case of electrolysis of a single salt is confirmed by a study of particular cases. For instance, the following table sums up the author’s observations on a mixture of 2; by volume of a solution of Na,SO,, and 4 of a solution of CuSO,, both pure and saturated when cold. The polarisation of anode is so small as to be negligible; the polarisation of cathode is given for various intensities of current in ten-thousandths of an ampére per square centimetre. Current Intensity Polarisation of Cathode in Volts 7 042 10 044 15 045 € . a ee Brilliant deposit of copper. 36 100 41 162 44-7 "298 J iene Brown deposit. 150 1:585 Abundant evolution of hydrogen. 1 Unless one artificially keeps it neutral: see D’Almeida, Annales de Chimie,, 3e série, t, ii. p. 257. 350 REPORT—1886. The brown deposit of oxide appears as soon as the polarisation exceeds ‘28 volt ; the polarisation increases first very rapidly, then slowly, and its limit is very nearly the number (1°428 volt) which corresponds to the decomposition of Na,SO, be- tween copper electrodes. _(It is slightly sophisticated by the extra resistance of gas bubbles then given off.) Tosum up: first is decomposed OuSO,, which theoretically consumes no energy (the electrodes being copper), then comes in the decomposition of acid water (‘28 volt), finally that of sulphate of soda (1°424). As for the conductivity of the mixture tt remains perfectly variable in spite of the variability of the electrolytic reactions. M. Bouty then quotes a saying of Wiedemann, that from a mixture of any of the following metals, Zn, Cd, Pt, Cu, Ag, Au, any metal which follows in the list is deposited to the exclusion of any which precedes. This is manifestly in accord with the above law, for the metals are in order of thermal equivalents. But the fact is only true for feeble currents. With strong currents a mixed deposit is obtained. To sum up: liquids have, like metals, only one mode of conducting electricity. © Also they have, like metals, only one contact E.M.F. with an electrode of invariable composition. But the result of electrolysis being to modify both electrode and liquid round it, their contact E.M.F. alters in a variable manner—whence polarisa- tion. Sur la Conductibilité Electrique des Dissolutions Salines trés Etendues. Par M. E. Bovuty.! Abstract by Oliver Lodge. I. Historical. ‘ The electric conductivity of salts dissolved in water varies with concentration in a manner extremely complex and differing for different salts. One possesses neither general law nor empirical formula, of however limited an application. One conceives @ priori that this conductivity depends on the chemical nature of the salt, on the hydrates it can form, and on their stability ; experience establishes also that it is not without relation to some physical properties of the solution, in particular itsviscosity. But the separation of these circumstances has not yet been made. ‘There seemed to me room first to simplify the problem by considering only solutions of identical physical properties. I have therefore chosen solutions so dilute that their density and viscosity are the same as pure water ; their conductivity is yet relatively enormous, and can be measured easily by an electrometric method derived from that of M. Lippmann.’ In this method as now applied the tapping electrodes are zinc in sulphate of zinc, communication being established between the experimental fluid and the sulphate of zine by a pair of capillary openings in the experimental tube. ‘ The difference of potential between these tapping electrodes is either measured by a Lippmann electro- meter and compared against another difference taken at the ends of a known wire in the same circuit, chosen so as to be as nearly equal in resistance to the liquid as possible ; or, what is plainly better, it is compensated by an auxiliary wire, and the electrometer brought to zero. The author quotes Kohlrausch’s views as expressed in his paper in Wiedemann’s « Annalen, vi. pp. 1,51, 145, 210 ; but he objects to them as founded. too much on ex- trapolation, the conclusions being stated for extremely dilute solutions, while those experimented with contained jth of their weight of salt. ‘So, although my results present a general agreement with those of M. Kohlrausch within the limits in which he has himself worked, I find myself led for their interpretation to conclusions absolutely different from that of the learned German professor.’ II. Method of Measurement. The liquids to be compared are contained in two long vertical inverted U tubes 1 Annales de Chimie et de Physique, 6e série, 1884, t. iii.; also Journ. de Phys. 9e série, t. iii. p. 325. See also Foussereau, Journ. de Phys. t. iv. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 351 dipping with their open ends into two pairs of porous pots, each pair full of the same liquid as isin its tube. The four pots, and also the two main (zinc) electrodes, are contained in six separate glass vessels, all full of sulphate of zinc solution, connected up by short stout siphon tubes, as shown in fig. 1. The tapping elec- Bree i; trodes are zinc blocks, each in a Woulffe’s bottle of sulphate of zinc, with a projecting and recurved full tube able to dip into any part of the liquid in the glass cells outside the porous pots, and so make connection (see fig, 2), Fie. 2. | E E E | After taking readings for the two tubes filled with different liquids, they are both filled with the same liquid and fresh readings taken, so as to compensate for inequalities between the tubes. III. Conductivity of very dilute Neutral-salt Solutions. “When one takes a solution of a neutral salt, already pretty dilute, and doubles the quantity of water it contains, the specific resistance is in general far from being doubled, as one would @ priori expect; it is multiplied by a coefficient A, smaller than 2, which increases progressively with dilution and tends towards the limit 2, but only for excessive dilution. Here, for example, are’some numbers furnished by sulphate of zinc :— 352 REPORT—18 86. Initial concentration Ratio al | Initial concentration Ratio A | : 3b 1°684 | sis 1:752 ay 1-712 oh 1:805 io L721 | w40 1845 a 1:739 TET) 1:953 ‘Chloride of potassium gave in one experiment— Initial concentration | Ratio A | Initial concentration Ratio A | | 4 1-921 | sts 1-933 a | 1:943 | ah0 1:958 120 1931 | seo 1:945 ‘ Anhydrous salts behave in general like KCl, that is to say, the ratio X is very near 2, even for moderate concentrations. Hydrated salts, on the other hand, are comparable to sulphate of zinc, and it is only for very great dilutions that their ratio \ approaches the value 2.’ M. Bouty considers that at sufficient dilution the molecular conductivity of all salts is the same. For salts without water of crystallisation a concentration of zz or so may be permitted; but for hydrated salts it is necessary to go below these limits, a thing which requires the possession of absolutely pure water, and he is only able to show that they approach equality to the other class of salts when very attenuated. Two tables follow, showing ratios of resistances compared with ratios of concentration, first for anhydrous salts, and then for salts which crystallise with a definite amount of water, KCl being taken as the standard of reference. IV. On the Migration of Ions, and its Relation with the Conductivity of Salt Solutions. The author styles the case when the migration number of each ion is simply } as ‘normal electrolysis,’ and he quotes results of Hittorf to show that the salts which thus behave are anhydrous salts, e.g., AmCl, KCy, KCl, K,SO,, K,CrO,, KNO,, KBr, KC1O,, KCIO,, Ag,SO,, KI, AgNO,. For all these Hittorf’s number (”) is very near ‘5 and scarcely varies with dilution. But for salts which definitely combine with water neither of these statements holds. Here are Hittorf’s numbers. § represents the weight of water combined with 1 gramme of the salt ; expresses the loss of concentration at the cathode while 1 equivalent of electrolyte is decomposed. It seems from the following table that hydrated salts approach normality as their solutions become very dilute. They then also tend to obey the law of equivalents (A/m = const.) ; so the two things are connected. ‘ When a salt obeys the law of equivalents, its electrolysis is normal (migration number 3); when it does not obey, it is abnormal, and the divergence which the law presents to the law of equivalents is so much the greater as the number n differs more from the normal yalue‘5.... There is thus, between the resistance of salt solutions and the phenomenon of migration, a very close relation impossible to overlook.’ [! This ‘ratio A’ is plainly the same thing as Arrhenius’ ‘ exponent of dilution,” only more simply introduced. I have shown in remarks on Arrhenius’ memoir (first. part, see below, p. 360) that the meaning of this ‘ratio A,’ in so far as it is con- stant, is that conductivity varies as a power of the concentration, % ao m™, where 7 =log A/log 2.] | * ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 353 Salt SS) n Salt Ss n y 3:5 66 1:6974 ‘780 : es 9-0683 771 || BaCl+2H,0 . aie = 23608 765 2-739 “749 CaCl, . . 5:3 “7e9 3:9494 727 762 138-26 673 — 229-2 683 6°35 "724 9:56 712 CuSO,+5H,0 . | 18-08 675 3306 ‘158 39°67 MnCl, +4H,0 .| {jon se 14s3 } 645 2524 ‘778 2:48 ‘806 ZnuSO,+7H,0 . 4-052 "760 MgCl,+6H,O . 22-2 ‘706 128-3 ‘677 11:77 “641 | \2413 678 || NaeSO,+10H.0 | { 55.65 634 A still more striking proof of this relation is afforded by some salts of which the electrolysis is not normal and does not tend to become so with increasing dilution. For instance nitrate of soda -— Ss n 2-066 588 2-994 600 ee 34-76 614 128-7 G14 [The meaning of x = 614 is that when an equivalent of NaNO, is decomposed, °614 of an equivalent is lost from neighbourhood of cathode and °386 from neigh- bourhood of anode. | __ The number thus varies little with dilution, and appears rather to diverge from the normal value ‘5 as dilution increases, A comparison between NaNO, and KCl of the same concentration has fur- nished me with the following results :— Concentration Ratio of Resistance Ratio of Equivalents Z00 1-489 ‘141 ha 1-476 ji The specific resistance thus scarcely varies with dilution, and it is almost 1:3 time its theoretical value. The permanent anomaly of its electrolysis corresponds to a permanent departure from the law of equivalents. Salts which behave some- thing like nitrate of soda are LiCl, NaCl, CaSO,, NaNO,, NaClo,, Ba2NO,, Cal, Ba2Cl0, ; Li,SO, + HO, Ca2NO, + 4H,0, SrCl, + 6H,0, NaI + 2H,0. V. Discussion of the Results of M. Kohlrausch. Kohlrausch attributes to every ion a specific molecular conductivity which it preserves in every combination. Bouty asserts that the molecular conductivity of all neutral salts in very dilute - solution is the same ; and would thus consider that the numbers of ionic velocity given by Kohlrausch should be all equal, which they by no means are. He proceeds to criticise Kohlrausch’s experiments by saying that the solutions he used were too concentrated, the weakest containing 5 per cent. of salt, while Bouty’s went as low as ‘025 per cent. ; ‘On the other hand Kohlrausch’s tables are too comprehensive, they include electrolytes which cannot be directly compared : let us leave on one side for the 1886. AA 354 REPORT—1886. moment, first, acids and basic hydrates; second, salts decomposed by water, double salts, &c.; third, neutral salts which remain abnormal even in very dilute solution ; and consider only the salts I have called normal.’ The class of bodies most favourable to M. Kohlrausch’s results are those relating to anhydrous and nearly ‘normal’ salts. Here are his numbers for the following ions. The numbers for Am, K, Cy, Cl, Br, I, and NO, differ very little from a mean value 50. But for Ag, SO,, ClO,, the atomic conductivity is 40, and for CO, it is 36. “To compare these numbers with my own, this is what I have done. Consider, for example, K,SO,; its molecular resistance according to Kohlrausch is ie 488 48 * 40 ~ 1920° That of KCl, which I have used as a standard, is ; le le 97, 48 * 49 ~ 2352" The ratio of these is 11114. I have measured this same ratio at different concentrations, viz. 3, 545, aio» xo5o? and find numbers which, divided by the ratio of equivalents, give respectively 1288 1:144 1:074 1:011. These evidently tend towards the limit 1, and not to the number 1:1114 proposed by M. Kohlrausch.’ Similarly with K,CO, and AgNO,. ‘For sulphate of silver compared with KCl, Kohlrausch’s table would give 1:21, which I find by experiment ‘981. ‘ These divergencies are not enormous, but they get much bigger if one proceeds to study normal hydrated salts whose conductivity varies so rapidly with dilution. ‘ Kohlrausch’s numbers for the following metals are very different from 50 :— Ca 26 Ba 29 Cu 29 and 12 Mg 23 and 14 Zn — and 12 ‘When two coefficients are given, the former belongs to ordinary salts, the other to sulphates, which otherwise M. Kohlrausch cannot get to obey his law.’ Comparing these with KCl in the manner already explained, M. Bouty gets the following table, in which Kohlrausch’s numbers are also inserted for comparison. Limit according to Kohlrausch Concentration 20 500 To00 | zo00 As given by Corrected Bouty by O. L. CaCl, . : ; . | 1437 | 1:339 | 1:251 | 1°181 1428 1:29 MgCl,+6H,O . . | 1:339 |1:277 | 1-131 | 1-029 1549 1:34 BaCl,+2H,O . . | 1:290. | 1133 | 1-081 | 951 1:331 1°24 Mg2NO,+6H,0O . -| — |1:323 | 1:249 | 1-163 1581 1-4 Cu2NO0,+6H,O . . | 1474 11-281 | 1°253 | 1-135 1363 1:29 Mgs0,+7H,O . . | 2777 11879 | — |1:249 2°834 1:80 Cu80O,+5H,O0 . . | 3°1380 | 2-272 | 1°591 | 1°310 3123 1:86 Zn80,+7H,O . . | 2°924 |1:923 | — | 1-220 3°123 1:86 1 This is a mistake. The velocity numbers themselves must be added, not their reciprocals; so for K,SO, 48 +40=88 is the conductivity, and for KCl it is 97 ; hence the ratio is 1:10. The difference being so small I have left the figures of M. Bouty unchanged, especially as the ground of his arguments is only partially affected, not removed. In a note to the September J886 Journal de Physique, p. 428, M. Bouty admits his slip. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 355 “Tt suffices to read the numbers in any horizontal row to see that they tend towards the limit 1, not towards variable limits according to the nature of the salt, The ratios deduced from the table of Kohlrausch agree very nearly with the numbers in my first column for concentration +.’ Polarisation is so strong at the contact of metals with salts of Mg and Al that perhaps polarisation was not altogether avoided by Kohlrausch for the case of the magnesium salts above. ‘To sum up: Molecular conductivities tend visibly to equality for hydrated as well as for anhydrous salts, and the disagreement of my results with those of Kohlrausch finds itself explained in the most satisfactory manner.’ VI. Application of Faraday’s Law to the Study of the Conductivity of Salt- solutions. ‘The law which I have just announced may be extended to a variety of salts. It suffices to know the manner in which the salt is electrolysed, and what quantity of salt is equivalent to KCl, for the application of Faraday’s law.’ The author then gives figures for various salts, classifying them thus:— Salts with several equivalents of acid. Double salts decomposed by water (including alums). Simple salts decomposed by water (tin salts and Fe,0],). Stable double normal salts (K,FeCy,, &c.) Double abnormal salts. Phosphates and arseniates. Bicarbonates. Mercuric salts. Tartar emetic and a couple of cobalt compounds. “HQ MOE AUS MA ° ° He finds that HgCl,, HgBr,,and HgCy, are unique ; they are insulators. Water containing 5 grammes of one of these substances to the litre conducts very little better than pure water: 200 times less than what the &/m law would give. Sal alembroth, however, conducts. VIL. Organic Substances. Organic salts differ in no essential character from salts of which the acid and base are mineral. If the electrolysis is normal the law of equivalents rigorously applies, otherwise it does not, just as with mineral salts. Bodies like alcohol, glycerine, glucose, urea, &c. are very bad conductors, and it is difficult to make sure that the feeble conductivity they show (when com- mercially pure) is not due to the presence of traces of salts. VIII. Conductivity of very dilute Acids and Bases. The author has been led to the following conclusions :— ‘ Acids and bases which dissolve in water without combining with rt furnish tnsulating solutions ; on the other hand, when these substances combine with water in a manner more or less complete they conduct in the same way as salts. ‘But a given acid or a given base often forms with water several different com- binations. These combinations are usually unstable in presence of excess of water ; they are dissociated more or less by elevation of temperature and by dilution. It is only in a manner altogether exceptional that a monobasic acid can exist in dilute solutions in the monohydrated state, and without mixture with superior hydrates ; its mode of electrolysis and its conductivity will vary in a corresponding manner. It is therefore not legitimate to liken acids and bases in aqueous solution to neutral salts ; the law of equivalents cannot be directly applied to them.’ Then follows a twelve-page discussion of results, to establish these laws ; from this I make a few extracts only. The case of sulphuric acid is interesting, since it can crystallise with either one, two, or four, molecules of water, and it undergoes maximum contraction when combined with six atoms. It is known also to possess a maximum conductivity AA2 356 REPORT—1886. for sp. gr. 1:25. M. Bouty finds that the ratio X attains a minimum for a concen- tration about 1/500, as the following table shows — iti i 1 1 1 1 1 1 a Initial concentration . 5 sean Waa 1 1 Ae. ee eee L917 1894 1-867 1856 1849 1-854 1881 1942 2-002 ‘One does not see how to explain a variation of this kind except by a change in the nature of the electrolyte (7.e., of the dissolved hydrate),’ By making the hypothesis, which Bourgoin made, that the hydrate really decomposed by the current was 8,O0,, 6H.,0, M. Bouty considers that the anomaly of electrolysis as expressed by Hittorf’s values of 2, and also that of conduc- tivity, is explained. These are Hittorf’s values of m for dilute sulphuric acid. 1§='5574 1:4383 5415 23°358 97°16 161°4 nm =*400 288 174 177 212 206 Hydrochloric acid is in much the same condition as sulphuric acid: it conducts as if its molecule contained three equivalents of basic hydrogen. One does not know such a hydrate, but there is probably a mixture of hydrates present. Oxalic and picric acids are the best conducting organic acids. Other acids con- duct hardly at all when strong, and dilution has an enormous effect upon them — probably because they combine with water forming compounds analogous to salts. IX. Influence of Temperature.—To study this, the U tubes of fig. 1 are turned upside down and immersed in a bath. The result is that for normal neutral salts the conductivity is a linear function of temperature. k=k,(1 + dt), where } is the same constant for all the salts, and equal to about ‘0337. This agrees with Kohlrausch also. It is noteworthy that Poiseuille gives the quantity of water which flows through a capillary tube, under a given pressure, as proportional to— 1+ :03365¢ + *000212?, It is impossible not to be struck with the identity of the principal coefficient in this formula, with 6 in the conductivity formula; showing that resistance is of the nature of a friction, as Wiedemann surmised. For abnormal salts the coefficient b is a little greater, and a parabolic formula is required at higher temperatures. So, although these salts conduct worse than normal ones to begin with, they improve faster when heated, and accordingly their abnormality decreases with rise of temperature, For acids and bases the temperature-coefficient is rather less, being only 0119 for sulphuric acid, and -024 for hydrochloric. Probably warming breaks up some good-conducting hydrate, and so spoils conductivity almost as fast as it otherwise improves it. ‘To sum up: I believe I have established that the electrolysis of neutral salts is a simple phenomenon, and that there is only one elementary law of conductivity in harmony with the law of electro-chemical equivalents. Apparent exceptions only reveal to us the complexity of certain solutions which are not directly com- parable with those of KCl or K,SO,.’ On the Employment of Alternating Currents for Measuring Liquid Resistances. By MM. Bovry and Foussrreav.? The authors criticise the employment of alternating currents employed by Kohl- rausch and many others in the hope of diminishing the effect of polarisation. They point out that self-induction in the resistance-box is fatal to silence in the telephone [naturally], and only succeed in getting good results when they replace wire in their bridge by liquid resistances, describing for this purpose a liquid rheostat. Even thus, however, they hardly get concordant results when they try to apply the method to extremely weak solutions. ’ S means weight of water combined with one gramme of acid. * Journal de Physique, 2e sér. September 1885, t. iv. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 357 On Mechanical and Thermal Effects accompanying Electrolysis. By M. Bovry. Brief Abstract by Oliver Lodge. A series of short memoirs have been published by M. Bouty in the ‘Journal de Physique’ on a branch of the subject not very immediately connected with that which at present concerns us. I had occasion to refer to part of them in a commu- nication on the seat of E.M.F. in the voltaic pile. (See ‘B.A. Report,’ 1884, pp. 492 and 513-518, or ‘ Phil. Mag.’ vol. xix. 1885, pp. 189 and 343 to 350.) The references to them are as follows :— 1. On some mechanical and thermal effects accompanying electrolysis (‘ Journ. de Phys.’ 1879, t. viii. pp. 289 and 341). 2. Thermo-electric and electro-thermic phenomena at contact of metal and liquid (1880, t. ix. p. 306). 3. On the contraction of galvanic deposits, and its relation with the Peltier pheno- menon (1881, t. x.) In the first of these papers, metals are deposited on silvered thermometer bulbs and the mechanical compression caused by the different deposits studied ; Wertheim’s results in elasticity being applied to them. The effect of heat on such metallised thermometers is also discussed. Metallised thermometers are then used as electrodes to examine the changes of temperature which occur while various ions are being liberated. During the elec- trolysis of CuSO, or ZnSO, the anode is slightly warmed, the cathode slightly cooled; inverting the current cools the new cathode distinctly. Electrolysing dilute H,SO, with platinum coated thermometers, the anode is quite warm, the cathode scarcely at all. This is the permanent effect. Inverting the current cools the old anode, sometimes } degree below the temperature of the surrounding liquid. The effect can be repeated seven or eight times, although with decreasing intensity, if one takes care to stir the liquid between the inversions. Replacing H,SO, by HCl, the permanent effect is very small, but both poles heat strongly at each inversion. With PtCl, one observes at each inversion a cooling of the old anode and a heating of the old cathode. In every case examined, anode is hotter than cathode in the permanent state. In the second paper, metal-liquid junctions are warmed and cooled alternately so as to give thermo-electric currents, the E.M.F. of several circuits being mea- sured, An attempt is then made to measure absolutely the coefficient of the Peltier effect at these junctions when a current passes ; a method suggested by Max- well (‘ El. Electricity,’ p. 146) being used. The result is that the author believes the effects to be purely physical, without known relation to the heats of combination or the latent heats of solution, but connected exactly with the thermo-electric forces of couples corresponding. The thermo-electric laws of Sir W. Thomson are believed to apply without modification. Chemical effects are regarded as disturbances pro- ducing parasitic heats. In the third paper, the author reconsiders the contraction of galvanic deposits in the light of the Peltier effect, and comes to the simple and satisfactory conclusion that the two phenomena are immediately connected. Each envelope being deposited at a rather higher temperature than it is able afterwards to maintain, a state of com- pression naturally results. This view he sustains by experiment. Recherches sur la Conductibilité galvanique des Electrolytes (152 pages). Par Svante ArrHeEntus. Mémoire présenté & V Acad. des Sciences de Suéde le 6 Juin 1883. Published at Stockholm, Konigl. Boktryckeriet. Norstedt and Soner. PART I—On the Conductivity of Extremely Dilute Aqueous Solutions, deter- mined by means of the Depolariser (63 pages with plate). Critical Analysis by OLIVER LoneE. Wuarever may have been the importance of the first part of this memoir at the date of its appearance (1883), the publication last October in Wiedemann’s/Annalen ’ 358 REPORT—1886. of a masterly memoir by Prof. F. Kohlrausch on the same subject throws it into the shade ; for there can be no doubt that while the ground covered by both is similar, the Kohlrausch memoir is greatly superior, both in the experiments made and in the discussion upon them.! A brief abstract of this portion of Dr. Arrhenius’s paper is all, therefore, that is now necessary ; and if my criticisms on parts of it appear in any case caustic, I must express my regret to the author for the adverse opinion, and trust that my appre- ciation of a great deal in the second part wili compensate for it to some extent, It sometimes seems as if the author allowed himself occasionally to indulge in an exploded type of reasoning, wherein, by manipulation of imaginary data, a confu- sion is produced, out of which emerge several laws more or less in agreement with experience, which are thenceforth labelled and referred to as theoretical deductions. t may be, however, that the italicised and numbered statements throughout the paper are not intended for strict statements of deduced law, but are merely summaries of more or less probable truth. In that case it is their form only which is misleading, and one would judge them by a different standard. I proceed to give an account of the contents. : §§ 1-8 are devoted to an account of the experimental method employed, and to a justification of it. The method consists in the use of a differential galvanometer, one of whose branches consists of ordinary wire, while the other contains a current alternator in the shape of a wheel turned by hand, with alternate bars on its periphery rubbed by two springs (Edlund’s ‘depolariser’). The alternating current from this in- strument is led to a switch, which is able at pleasure to throw into circuit either the experimental tube of liquid or a wire resistance box. A battery is arranged so that its current divides fairly equally between the two branches of the galvanometer; and one portion of the current, after being rendered alternating by the above arrangement, is diverted by the switch ‘either to the electrolyte or to the adjustable resistance-box. The resistances of the liquid and of the box are considered equal when the deflexion of the galvanometer is in- dependent of the position of the switch. f I must confess to surprise that this can be a satisfactory mode of measuring resistance: self-induction and electro-chemical capacity being so mixed up in it,” and the so-called depolariser being a very unsatisfactory instrument. Apparently, however, results fairly comparable with each other can be obtained. § 9. Calculation from the Experimental Data.—First, the conductivity of the original water used as solvent is subtracted from that of the solution, and the re- sult claimed to be the conductivity of the salt alone. For this rule, asan empirical process justified @ posterior’, there may be something (not much) to be said. But as a corollary from a ‘law’ subsequently proved in this paper (§ 15, law 2) it is unreliable. Probably not much harm is done by using this rule in the special cases considered ; at any rate, Kohlrausch does the same thing: but it is well to notice that the rule k=,+k,, for the conductivity of a mixture, if stated as a general and @ priori law, assumes two things: Ist. That the law of divided circuit must hold whenever two conductors are intermingled ; which is untrue.’ 1 See § 6 of a letter by Dr. Arrhenius printed on p. 386. * See § 1 of a letter by Dr. Arrhenius printed on p. 384. ’ Dr. Arrhenius in his letter, page 385, naturally and justifiably objects to this statement as dogmatic. The reason it is here put so briefly is that the point was referred to in my last year’s paper, see Aberdeen Report, top of page 728. Observe, I only object to the assumption that the law of divided circuit must be true: it may be true in some cases, but a possibility cannot be made the basis of a deduced law. In order that the combined resistance of two solutions when mixed may be the semi- harmonic mean of their separate resistances when alone, the following conditions are necessary and sufficient : (1) The solutions must not affect each other’s conductivity in any way ; the fact of mixture must not increase dissociation or change viscosity, for instance. 4 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 359 2nd. That the conductivity of water itself remains unaffected by the pre- sence of a foreign body ; which is improbable.! Effect of Dilution.—A great part of the paper is taken up with the effect on conductivity which dilution with an equal quantity of water causes to solutions of yarious salts. This mode of expression is a roundabout substitute for a straight- forward expression by curve or formula for the relation between conductivity and concentration such as Kohlrausch attempts to give. However, as Dr. Arrhenius evidently prefers this mode of expression, I translate his introduction of it (page 25 of his memoir). ‘Table A shows that when a saline solution is diluted in a certain ratio [1 : 6:08, for instance] its conductivity diminishes in a certain other ratio [mot in general a very different one]. To render these numbers comparable among them- selves in the different series a recalculation has been made, in which all dilutions are reduced to the ratio 1 : 2. ‘This calculation is made in the following manner. If 1 : wis the proportion between the dilutions of two solutions of the same salt examined consecutively (¢.e., if one of the solutions is wu times as dilute as the other), the proportion between the resistances in the two cases is, say, 1 : ” (the value of n being taken from the table) ; that is to say, one of the solutions has a conductivity m times less than that of the other. ‘If now 1: «w is the proportion between the resistances of two solutions when the dilutions are in the proportion 1: 2, the following relation will hold good. If the dilution is 1 : 2°, the ratio of resistances (if the process is effected in a uni- form manner) ought to be 1: z2?. In consequence we have 1: 2?=1 : w, and 1: a =1: n, which enables 2 to be calculated by the following formula :— log log z = log log n—log log u+log log 2. ‘The values of z calculated from this formula, which, according to what has just been said, signifies the proportion in which the conductivity of one salt- (2) The current must divide itself accurately between the two constituents, so that whatever starts to go by one substance must keep to that all the way, and not go partly through one, partly through the other. If these two conditions are not satisfied, the law can only be true in any particular case by some semi-accidental sort of compensation. True there is much to be said for the fulfilment of the second condition in many cases of electrolysis, perhaps in all; but it cannot be regarded as axiomatic; and it is certainly not true of inter- mingled conductors in general, which is all I say in the text. The point may be illustrated thus. Take a square sheet of tinfoil, send a current through it between copper strips on its opposite edges, and measure its resistance. Now make an arbitrary cut across the sheet from one of these edges to the other. The current will divide between the two portions, and the resistance of each portion can be measured. The resistance of the uncut sheet will not in general be equal to the semi- harmonic mean of the two portions ; in other words, the law of divided circuit need not apply. It may apply, but only for the special case of a cut along astream-line. The statement, therefore, that the law of divided circuit must hold whenever two con- ductors are intermingled is untrue—Q.E.D. As to the question whether the law does hold for any mixed electrolytes we have the experiments of Hittorf and of Buff on the conductivity of mixtures; with the result, I believe, that, whereas all the mixed substances take part in conveying the current, no simple relation holds between the conductivity of the mixture and their ‘separate conductivities except in the case of some haloid salts. For them the law of divided circuits does seem to hold. To diminish the risk of misunderstanding, I may be permitted to point out that the remark made in the text is not a criticism of Dr. Arrhenius or of anybody. It relates to a general proposition or matter of fact, and is intended as a memorandum of a circumstance which it is very easy to see when pointed out, and rather easy to forget in practice when considering a special case ; cf. Guthrie’s Text-book of Elec- tricity, sections 244-247, first edition, which are all wrong in principle as well as cumbrous in detail. See §§ 2 and 3 of letter on p. 385. 360 REPORT— 1886. solution diminishes when it is diluted with water to double its volume, are laid down in table B. This quantity we name the exponent of dilution.’ Bis along table wherein, after all, x does not turn out a constant—though it is roughly so, several values of 2 being given for each substance according to its degree of dilution. The values of x for all the substances range from 1:7 to 2:3, and their average value would seem to be about 1°95. The above introduction to the formula for calculating x loses all meaning unless « is intended to be constant ; but, in so far as x is intended to be constant, the gist of the introduction may be paraphrased thus :— The first approximation to the relation between & and m (condustivity and concentration) is that made by Kohlrausch, viz., that the two are proportional.’ This is roughly true for very dilute salt (not acid) solutions, but it breaks down in a manner shown by Kohlrausch’s experimental curves for more concentrated ones, so that he suggests the formula— kim = A — Ams as a closer, though still rough, approximation. Arrhenius, however, prefers to assume (?.¢., practically, though unconsciously, does assume by his reasoning) that i is nearly proportional to m", where 7 is an index to be determined by experiment. This is fair enough as an hypothesis, and should have been set forth clearly, and - then negatived by the result of his experiments: or, as aclumsier and bulkier proceeding, the value of » might be tabulated for every substance at various strengths. Instead, however, of determining r, Arrhenius determines 2"; which he calls x, and tabulates. This number 2, his exponent of dilution, he calculates from the equation— log « _ log mjm’ _ logn [=r] log 2. log mim’ = logu ; I confess that it has cost me a good deal of trouble to disentangle the real meaning of this said dilution-exponent, and of the ideas involved in it.? I ought here to say that in 1884 M. Bouty independently expresses his results in terms of this same number, which he calls the ratio \ ; showing that it has some experimental convenience. Bouty, however, does give absolute concentrations, and he really doubles the dilution each time. Arrhenius gives no absolute con- centration ; he dilutes largely, and then calculates what would have happened if he had only doubled the dilution, by means of a formula which, after all, is not realty correct. Perhaps the idea in not giving absolute concentrations is that it is impossible accurately to tell them, unless absolutely pure water were available to start with. But the difficulty of impure water tells just as much at every dilution, for it is a medley of things you are really adding. A great part of the merit of Kohlrausch’s work is that he takes such immense pains over the quality of his water. § 10. List of bodies examined. § 11. Table A, giving resistance and temperature of different strengths of solution of the various substances, but no absolute strengths are given; ratios of dilution are all that are specified. The columns, in fact, show 1/n and 1/u. Table B contains the ‘exponents of dilution,’ x, calculated for the different substances ; it shows a slow increase in x as the solution becomes weaker, Table B’ contains similar numbers, calculated from some experimental results of Lenz for stronger solutions. The net result of these tables is that they help to confirm the later results of Kohlrausch. For all salts other than hydrates the value of 2 becomes practi- cally equal to 2 as the solutions become very weak, #.c., 7 becomes unity ; and this means simply that k/m for such solutions is approximately a constant. 1 See § 4 of letter on p. 385. . * In his letter on p. 386 below, § 4, Dr. Arrhenius denies that he had any theoretical idea in introducing the ‘ exponent of dilution.’ I accept his statement of course, and regret the time spent over the troublesome, and now apparently unmeaning, intro- duction quoted above. 3 See § 4 of letter on p. 386. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 361 For stronger solutions x diminishes; and this means simply that /m falls off, just as Kohlrausch’s curves more instructively show. §§ 12 and 18. Discussion of the Tables. é f § 14. Influence of Temperature on Conductivity.—Dilution and heating exert a similar influence on molecular conductivity. Carrer II].—THeory. § 15. On Conductivity considered as a Function of Concentration.—Kohlrausch and most authors suppose that i/m is constant for extreme dilution ; ‘nevertheless he seems to make the statement with a certain reserve, for in another passage he says, “ This number [gramme-molecules per cc.] can, according to all the experi- ments, be put proportional to the conductivity of attenuated solutions, provided extreme attenuation be excepied.” Nevertheless it is not difficult to prove that such @ proportionality follows from the principles postulated in his work: and that pre- cisely for solutions of extreme attenuation.’ Then follows a proof, based on Kohlrausch’s surmises and Hittorf’s hypotheses, (1) That k/m ts necessarily constant ; ; (2) That when two or more salts are dissolved, the conductivity of the whole as the sum of the separate conductivities ; and f (8) That the conductivity of a solution equals the sum of conductivities of salt and solvent. To all this it is necessary and sufficient to remark that the surmises of a philo- sopher, which are to some extent upset by his own experimental results and accordingly by him stated ‘with a certain reserve,’ afford a very insecure basis for an elaborate proof, and for deductions therefrom.+ If it be once granted—lst, that the conductivity of the water in solution is, under all circumstances, nil, or extremely small; 2nd, that every atom of a salt added conducts equally, and independently of every other;—the laws stated are pretty obvious without further proof. But it is of little use attempting to prove these laws by begging the question. § 16 contains statements numbered (4) and (5), viz., If the three laws are not true, tt must be because of chemical action between the substances. § 17. Hydrates (¢.e., hydrogen compounds, like acids and bases) are peculiar ; either because they dissolve glass, or because impurities contained in distilled water act upon them chemically, and alter them. § 18. Statement No. 6.—The ‘exponent of dilution’ ts less than 2 for salts, greater than 2 for hydrates. § 19. Exceptions. § 20. Nature of the Resistance of Electrolytes.—A hypothetical discussion of the friction between atoms, the mode in which ions rub against other molecules, and of the amount of rotation they produce in them ; with three conclusions, numbered respectively— (7) The resistance of a solution is greater as the internal friction ts greater. (8) The resistance ws greater as the tons are more complex. (9) The resistance is greater as the molecular weight of the solvent ts greater. § 21. Properties of Solutions of Normal Salts.—Discussion of some results of Hittorf, and four statements— (10) Salts which are able to form double salts are most likely to form molecular complexes. (11) Agueous solutions contain the electrolyte dissolved, at least partially, in the form of molecular complexes. (12) Dilution diminishes complexity towards an asymptotic limit. (13) The limit toward which the complexity of a dissolved normal salt approaches at extreme attenuation is the same for all normal salts. I feel that this brief analysis is not quite fair to the contents of these last sections, which are ingenious and interesting; but I scarcely think a detailed 1 See § 5 of letter on p. 386. 362 REPORT—1886. abstract of them would repay perusal, inasmuch as the author allows himself rather too freely the use of hypothesis concerning wholly unknown molecular interactions.!_ Perhaps it will be fairer if I give the réswmé in full. Résumé. ‘In the first six sections of the present work we have described a new method of measuring the resistance of electrolytic conductors. In this method we made use of rapidly alternating currents, produced by a depolariser constructed for the purpose by M. Edlund. We have tried to show the use of this method, and to make clear the practical advantages which it possesses. ‘In the next part we have treated the process of making the observations, and of calculating the results. Then we have displayed the figures found for very dilute solutions of forty-five different bodies. Finally, we have discussed pre- liminarily the figures obtained, with regard to the exponent of dilution, the mole- cular conductivity, and the temperature-coefficient. ‘In Chapter III. we have, guided by the data of MM. Kohlrausch and Hittorf, laid down the proposition of the proportionality between the conductivity and the number of electrolytic molecules of a dilute solution, as well as two other propo- sitions, according to which the figures of the preceding part were calculated (1) (2) (8). Moreover, we have shown that if these propositions are not applic- able, it is necessary to suppose that by dilution of electrolytic solutions chemical reactions are set up, (4) (5). Proceeding from these different proposi- tions, we have shown that all salts, properly so called, in solution are composed. of complex molecules, which are partly destroyed by dilution. We have also indicated the manner in which these complexes are formed. ‘ By aid of this conception the properties of salts at all dilutions have been explained, as well as the properties of all electrolytes at considerable concentration, ‘On the other hand, hydrates,” and salts which partially transform themselves into hydrates, manifest other properties when much diluted. We have shown that this singularity can be explained by the action of impurities which accompany the water used to dissolve them. ‘ By some considerations as to the nature of galvanic resistance we have been brought to the conclusions numbered (7) (8) and (9), of which the two latter com- plete the first: these indicate the long-known relation between galvanic resistance and internal friction. The two propositions (8) and (9) are also in agreement with published data.’ Thus much is a meagre account of the first part of the complete memoir. I now pass to the far more striking second part, and shall find it necessary to give a much fuller, and in many places verbatim, report. Tam not able to judge as to how much is original and new, as I am but slightly acquainted with the work of previous writers on similar subjects, nor am I at all confident how far the hypotheses made by the author are perfectly legitimate. So far as I am able to judge, however, and making allowance for possible inade- quacy of data and somewhat hasty generalisation, the paper seems to me to be a distinct step towards a mathematical theory of chemistry. The title affixed to it is ‘The Chemical Theory of Electrolytes,’ but it is a bigger thing than this: it really is an attempt at an electrolytic theory of chemistry. PART Il.—Théorie Chimique des Electrolytes. Par SvANrE ARRHENIUS. (89 Pages). Abstract and translation by Oliver Lodge. [Remarks by the abstracter are enclosed in square brackets. | § 1. Ammonia considered as an electrolyte. Kohlrausch has shown that a solution of ammonia, as regards conductivity, behaves differently from all other bases. It is a much worse conductor than potash, 1 See § 6 of letter on p. 386. ? By hydrates the author always{means hydrogen compounds like acids and bases. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 363 and its exponent of dilution is not much bigger than 1 [?.e., its conductivity, instead of increasing anything like so fast as concentration, scarcely increases at all]. Kohlrausch guesses that the cause of this is the prevalence of NH, in solution instead of NH,HO. Probably dilution increases the supply of NH,HO, and therefore assists conduction almost as much as it for other reasons weakens it. This would explain the peculiarly small exponent of dilution. (14) The conductivity of ammoniacal solution is caused by a small quantity of NH,HO, which is increased by dilution. [Surely it is rash to make definite statements like this on such a slender basis of fact.]? § 2. Case of acids ; activity. Acetic acid has the same properties as ammonia; so has boracicacid. Tartaric and oxalic have small exponents of dilution. Probably the behaviour of these acids, as well as of ammonia, is analogous to that of HCl, which only conducts in presence of water. Sulphuric, nitric, phosphoric, behave in the same way. Hence— (15) The aqueous solution of any hydrate * is composed of two parts, besides the water, viz., an active (electrolytic) part and an inactive (non-electrolytic) part. The three constituent parts of the solution form a system in chemical equilibrium, such that dilution increases the active and diminishes the inactive portion. How the inactive and active portions differ is not certain, perhaps only physically ; perhaps the active part is a compound of hydrate and solvent. To fix ideas we can introduce the notion of a coefficient of activity, defined thus :— The coefficient of activity of an electrolyte is a number expressing the ratio of the number of ions which are really in the electrolyte to the number of ions which it would enclose if the electrolyte were totally transformed into simple electrolytic molecules. [This ‘ coefficient of activity ’ is evidently the same thing as what, in accordance with dissociation ideas of electrolytic conduction, I called * the ‘ dissociation ratio,’ z.e., the relation between the number of atoms taking part in conduction to the whole number present. It may turn out that this ratio is unity, but it is in any case well to determine it; and the idea of Arrhenius that it is upon this that chemical activity and rapidity of interchange depends seems to me important. | § 3. Hypothesis of Williamson and Clausius, and consequence thereof. [The continual interchanges of atoms supposed to occur among the molecules on this view of conduction are here regarded as circular electric currents. References to the original statements of the hypothesis are given as follows: Williamson, Geen ‘Ann.’, vol. 77, p. 87 (1851); and Clausius ‘ Pogg. Ann.’, vol. 101, p. 347 )]- § 4. Deduction of some electro-chemical laws (16)-(20). [£.g., Faraday’s laws. I omit this section because it is not much use deducing laws like these from an hypothesis. The Williamson-Clausius hypothesis is of course in harmony with the fundamental laws of the subject, otherwise it would have been pretty soon abandoned. Probably the object of the author is to show how readily the known laws can be built up from one simple foundation.* One ' See § 7 of letter on p. 386. ® For ‘ hydrate’ always read hydrogen compound, either base or acid. % On page 756 of last year’s B. A. Report, Aberdeen. 4 See § 8 of letter on p. 387. 364 REPORT— 1886. statement deduced from this hypothesis is worth quoting (see also Wiedemann, ‘Elek.’, vol. ii. p. 924).] (20) Every body which acts chemically by double decomposition on an electro- lyte is ttself an electrolyte, as well as the products of the decomposition. Therefore water, alcohol, aldehydes, Se. §c., are electrolytes, and therefore conductor's. [The a priort manner in which this statement is made is striking; so is the note immediately following. | ‘On this subject people have disputed for some time. They often attribute the feeble conduction observed in these bodies to traces of saline impurity,’ ! § 5. Relation between conductivity and chemical power of acids and bases. (21) The molecular conductinty of the active part of an acid (in dilute solution) ts constant, and independent of the nature of the acid. For if the chemical formula of an acid is HR, its molecular conductivity, accord- ing to Kohlrausch, ish+7. Now the molecular conductivity of dilute salts with the same metal, MR, MR’, &c., is the same; hence »=7’=&c, And therefore it follows that for. acids also the molecular conductivity of HR, HR’, &c., is the same. A corollary is— (22) The more a dilute acid solution conducts, the greater is tts active part. Similar propositions may be stated for bases. [The author then goes on to consider the idea of coefficients of activity more particularly in the light of the Williamson-Clausius view, and he gives reasons for supposing molecular conductivity and coefficient of activity to be closely related, and indeed proportional, to one another. He then says, let them be defined to be equal. ai K mn are destroyed (v, being the same for all electrolytes, is included in the constant K). In reality the B ions are also moving, but since v is the same for all, the only effect will be to change the constant K in such a way as to leave it nevertheless the same for all salts. In the same way we can show that if » is the number of A ions, and q the number of B ions in unit vol., the number of molecules A B formed in unit time is— Kpq. . Hence the number of A B molecules at the end of unit time in excess of those at the beginning—that is to say, the velocity of the reaction by which A B is being formed—is— K(pq-mn). If the hypotheses supposed in the foregoing are only approximately true, the above deductions are no more so. The effect would be to multiply the numbers pqm and n by different factors, so that the general aspect of the above-deduced expressions will be only slightly modified. The same thing can be said for the equations we deduce in the sequel. However, as in the actual state of science it is impossible to judge of the validity of these hypotheses, and as they have a certain degree of probability. and of all hypotheses are the simplest we can imagine, it is - my intention to prove that the deductions which it is possible to draw from what has just been said are compatible with experimental facts—facts of which we thus give a certain explanation. With the progress of science it is possible that one may see the necessity of modifying these hypotheses; the general reasonings will persist nevertheless, as well as the conclusions drawn from them. Now, suppose we have four electrolytes, A B, A D, C B, and C D, intermingled; let the number of equivalents of each, existing at a given moment, be m, J; Dy 2, respectively ; and the corresponding coefficients of activity a, 8, y, and 6: the velocity of reaction will be, according to the foregoing,— K{(ma+qB)(ma+py)—ma(mat+qB+pyt+nd)}, an expression which transforms itself into the following :— TGS Wa UU 10.0) ee bey (1) 366 REPORT—1886. A state of equilibrium will be attained when the velocity of reaction is nothing. If then m originally equalled 1, and a quantity « of the body A Bhas been transformed, the final state will contain 1—w, n—w, +2, p+, equivalents of the bodies AB, CD, AD, CB, respectively. The equation expressing equilibrium will thus be— Q=ayi@—=ayia or Cp 2) (gr) By ee ee (2) or, if p and q are zero, a case often realised in practice— Qe ai@i— tad ia? By o-) sca) acy a tee) Now introduce the following definition:— . . . Two electrolytes like AB and CD, which have no common ion, are to be called conjugate; and two like ABand AD, or A Band OB, are to be called opposite. Equation (2) expresses the fact that an equilibrium occurs between the system of two conjugates, AB and CD, and the system of their two opposites, AD and CB, which are conjugate to each other. From that system is formed this system, and vice versd; wherefore equilibrium occurs, because the number of circular currents in which both systems are engaged is the same in the two cases. This is precisely the signification of equation (2). This equation immediately shows that, (23) As soon as the relative quantities of the ions, A B C D, are given, the Jinal result is independent of their original form of combination, whether A B and CD, or A D and CB, or any other form. This proposition is sufficiently natural to need no proof. Moreover, it has been yerified by the work of MM. Guldberg and Waage and Ostwald. Solving equation (2) we get pe atin Da Bog y)), /((2Me2) +By(e+ a). at Bye) ig 2(By—ad) in 2(By—ad) By-aéd or for the special case when g and p are zero— _ ad(n+1) | ad(n+1)\*, ad.n a(ay 8) ee ce * petsa) The sign of the radical is always the same as that of By—aéd. If it should happen that 8 y=a6 the above solution fails, but, returning to (2), we see that in this case— =) nest a eal CRM aM) te. ils so « is always unambiguously known. Differentiating equation (2), we get— dn ,a(ad)_d(By)_ dg _ dp n—xX ad B +X pre dx = T 1 1 il . ° ° . . ° (4) ——+ + qtx p+tx 1l-x n-2x If, now, a, B, y, 6, are the coefficients of activity of four bodies, AB, AD, _ CB, CD, and if the product, a5, for two conjugate bodies is much greater than that, By, for the two opposite bodies, one finds realised a case of very great im- portance—namely, the equilibrium of four bodies, acid, base, salt, and water. According to equation (2), if the original quantities mixed, of acid, base, and water, are 1, n, and p equivalents, there are formed 2 equivalents of salt and of water, where— (p+a)e = 59-2) (n—2), ete ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 367 ' For strong acids and bases ad/@8y is a number of several millions, while 2 is necessarily always less than 1 and z: hence to satisfy the equation it is neces- sary that (1—.) (n—~) shall be very small (unless p is enormous) ; that is to say, x must be almost equal to 1 (if n is greater than 1), or to m (if 7 is less than 1). (24) If one mixes a strong acid with a strong base, they unite for the most part to a salt, in such a way that there is formed a quantity of salt always a little less than that of the hydrate of which one has added the smallest eyuivalent portion. [This is rather an anticlimax. ] The clearest way to see this is to work some numerical examples. We have therefore made calculations on mixtures of a strong base (caustic soda) with a strong acid (nitric acid) on the one hand, and of a weak base (ammonia) with a feeble acid (boracic acid, supposed monobasic) on the other. The figures employed are taken from a previous section,' with the supposition that the molecular conductivity of ammonic borate is equal to that of ammonic carbonate (an hypothesis which ought to be approximately correct). We have thus calculated that if one mixes 1 equivalent of acid with m equivalents of base in 100 equivalents of water, the amount of salt formed («) is given in the table below for several values of n. 1 Mitric Acid and n Caustic Soda. 1 Boracie Acid and n Ammonia. n xz | n Zz 4 4999981 4 ‘245 1 “998659 1 “404 2 -999998 2 “634 3 “T41 (The molecular conductivities used in this calculation are probably— For HNO, a= 3x1075 For boracic acid. a=4:4x10-9 _ For NaHO 6=1°5 x 10-5 For ammonia . 6=8-4x 10-8 For NaNO, . B= 6x10-§ For ammonic borate8= 4x 10-5 mor HO. . y= 10-2 Forwater. . y= i aé so that —— in the first case equals 10 , and in the second case equals 100, or Eipiabouts ] What we have just said applies specially to the formation of salts of strong acid and base when the quantity of water is very considerable. From the above example (the formation of NaNO,), as well as from proposition 24, we proceed to de- duce the following observation, true for salts of strong acid and bases :— (25) The quantity of salt formed when one adds a strong base to a strong acid as sensibly proportional to the quantity of base added, until the acid is saturated, after which the formation of salt sensibly ceases. An entirely different aspect is presented by the figures calculated for the for- mation of a salt from feeble constituents, such as borate of ammonium. In this case a6/Sy is not excessively great, so that for considerable quantities of water (p) it is not necessary for either 1—2 or n—w to nearly vanish. That is to say, although the acid is in excess, the free portion of base is nevertheless sensible, and vice versd. In this case we may apply equation (4), regarding all quantities con- tained in it except x and m as constant, and q (the original amount of salt) as zero. We thus find that— dn 1 1 I a teense) dx Mie) l-a pra a * [§ 5, t.¢., from Kohlrausch’s tables of molecular conductivity, as then published. ] 368 REPORT—1886. [which may be written more symmetrically, though less usefully for present pur- poses— dn _ n_n-1l n+p dx az @£=1 £+p Differentiating again, we get \— — Pn _ 2(p+1)(m—-2) dx* 2(p+x)(1—2)?’ which is always positive, since « cannot be greater than z. This we can render into words thus :— (26) If one adds a feeble base to a feeble acid, or vice versa, there is necessary for the formation of a given quantity of salt (dx) a quantity of base (dn) so much the greater as the formation of salt has proceeded further. Moreover, equation (4) shows that if m is greater than 1, the denominator is not very great, because 1—. differs sensibly from zero; so a will have a sensible n positive value even for n>1, which means— (27) If one adds a feeble base to a feeble acid, or vice versa, the formation of salt continues sensibly, even after the number of equivalents of the body added has surpassed that of the other body. The figures calculated for boracic acid and ammonia exhibit this property clearly. Between the two examples cited are a crowd of transitions which are realised by mixing a strong acid with a feeble base, or vice versd. Everything depends on the magnitude of the factor ad/8y, and on p, the amount of water present. The laws deduced above have been long known by chemists. They are fundamental, and occur in most reactions—that is to say, in all reactions of electrolytes. If in equation (5) the factor ad/8y is a small number, as is probably the case for alcoholates,? the quantity of salt formed is almost zero. So if one mixes alcohol with any base, it only forms a very little alcoholate. But, according to law (23), final equilibrium only depends on relative quantities of the ions present, so if one adds water to an alcoholate it is destroyed, and turns into alcohol and hydrates. Here the réles are changed ; water is anacid stronger than alcohol, so it is necessary that water shall displace most of the alcohol, as nitric acid displaces water from a hydrate, and this is in full agreement with fact. What is common to every case is the necessity of regarding water as an acid (or, if one likes it better, as a base), which concurs with other acids (or bases) in the equilibria. As, according to equation (4), i is always negative, one perceives that the presence of salt (¢) has always an opposing influence on its formation, just as water has. However, the quantity of salt present in the reactions is generally small enough for this influence not to be noticeable. § 7. Important case of double decomposition. From the simplified formula indicated above by an ‘ A,’ one can at once deduce some important propositions. From (2A), viz.— ad(1—2x)(m—x) = 2?By one finds, by a discussion like that preceding prop. 24, that if one mixes two bodies AB and CD, the bodies AD and CB will also form ; and that the more as aé/8y is greater. 1 [Dr. Arrhenius’s mathematical expressions are sometimes unnecessarily long, so I rearrange them whenever convenient without compunction. | 2 According to all authors, alcohol is a conductor very inferior to water. On the other hand, the conductivity of an alcoholate is comparable to that of a hydrate. (See my work on the conductivity of alcoholic solutions.) [Author's note. ] ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 369 According to (4A) [that is, (4) with p = 0, ¢ = 0], = is always positive, so— (28) The more one adds a body to a system in equilibrium, the more will the opposite bodies be formed. Then if the body is water, and one adds it toa salt, one has immediately the following consequence :— (29) Every salt dissolved in water partially splits up into acid and base. The quantity of these products of decomposition is so much the more con- siderable as acid and base are feebler and quantity of water greater. Let a and 6 be the coefficients of activity of salt and water, 8 and y the same for acid and base; then in the majority of cases ad is enormously smaller than By; consequently for small values of m1 (in the case of strong acids and strong bases n can without inconvenience rise as high as 10,000) we can neglect the term ad (n +1)/(@y—ad) in comparison with the radical, and so— adn a are; . . . . . NS Aor ae aa (6) If, on the contrary, 7 is excessively great, one gets— Ae) ae be mee Pr These two formulz indicate that— 30) The amount of salt decomposed by moderate dilution ts approximatel “pp Yy 2 ippr y proportional to the square root of the quantity of water used to dissolve tt (81) A salt is completely split up if the water used to dissolve it is infinite. What is here said about water is evidently applicable to every other dissolving electrolyte. On this subject (the decomposition of salts by water) one reads in the work of M. Berthelot (p. 199), ‘The process of decomposition by water of the salts of feeble acids is not always the same. Sometimes it increases little by little, either inde- finitely with each addition of water, or tending towards a certain limit. . . . . Sometimes, on the contrary, the decomposition of a neutral salt is accomplished almost wholly by the first dose of water.’ Thus, Ist. The salts of strong acids with strong bases are not decomposed. According to prop. 30 they ought to be. At the same time the example of the previous section shows that the salt NaNO, is only decomposed ‘13 per cent. by 100 equivalents of water. Such quantities cannot be observed by any thermic means (at least, not by any that M. Berthelot employed). This is the reason for supposing that these salts are not decomposed at all. . . . On the other hand, the salts of strong acids with feeble bases are notably decomposed by water. Ammoniacal salts behave in thismanner. In M. Berthelot’s work there are a crowd of examples. 2nd. Salts of feeble acids are notably decomposed. For example, ammonic borate is decomposed 59°6 per cent. by 100 equivalents of water. Such quantities are well marked by thermal actions. Nevertheless, from what we have just said, the decomposition ought to be illimitable. The reason why M. Berthelot has in certain cases only found a limited decomposition is probably because his thermal ex- periments did not permit the employment of more than 1,000 equivalents of water, and because the decomposition is at first proportional to the square root of the quantity of water added (later still less); whence the first dose of water has an effect equal to that of the three following doses, &c. 3rd. As for salts which are almost wholly decomposed by the first addition of water, they are those for which By is less than ad (alcoholates, for example). ' » means the number of equivalents of added substance—for instance, water— for each equivalent of original substance—e.g., salt. 1886. BB 370 REPORT—1886, § 8. Systems more complex. Concerning these salts we have already said enough. [Then follows a physiological application of law 29, and a reply to some feeble objections to the Williamson- Clausius hypothesis. | Tn general the case in which four electrolytes alone establish a chemical equili- brium is rather rare. The most frequent case is that of six or nine electrolytes acting on one another. However, it is not difficult to establish general equations for a system of nv electrolytes, composed of v cations and anions. Let them be the following :— 1 AE BOM, hdr’. op: (ce! Bg oN BAS PR amememanmyraine tens £5" Pye Sr « avbih'ac* bce cena Pe cedir) hhe\s, 3; Lael 3 with the respective coefficients of activity— Gi; Fightatiy day Cie Oa Od +) stot Fondeue: eonelael Gane eat Moreover, let the original number of equivalents in the solution be similarly— Tce 3. oe so UCC Oe Cat eam eC 057 and the extra number formed at the end of the process— Pee poetigs) ss eGo hohe Meee Further, let us call the quantity— ay (my + vj) = 15 the active mass of the electrolyte I, J; . Then, in the same manner as in § 6 above, we find a set of equations analogous to (1) and (2), and they take this form : ae ticle =" ry. 2 SM = Bry. 2 Ty ee i | te my | 7 These equations may be written— (©) _ 20) & constant as regards 4; Sqr) wl") that is, pay GE Ba = Si 211; 212; ; Sry - A To; vr, 4 "ji = ="13 — const.; 22 = const.; . . ; =” =const. ? ’ Yj; 2025 EN Mej Fa a! I Min T= "99°23 Non Mines Uae oie ‘le Ten 131 132 "33 T3n “To-y1 _ "o-?2 — : Mo-1)n Ty Tye Ton which are (x —1) (v—1) independent equations. But there are ny unknown quantities (2:;) to be determined. So it is neces- sary to have n+v—1 fresh equations. These are not difficult to get. We notice ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 371 that the quantity present of each ion, I; or J;, is not altered by the reactions ; hence it follows that— Sty = 0, and 2p Viz = 0, These are 2+» fresh equations, one more than is required, but one of them is not independent. Thus we have all the equations necessary for the solution of the problem. The general equation of the system (A) is— "So. TH ced or— ij Py = Py yy. This equation contains the following proposition :— (32) When equilibrium is established among any number of electrolytes, the product of the active masses of two conjugate electrolytes ts equal to the product of the active masses of their two opposites, just as tf no other electrolytes were present. This extremely simple proposition contains the solution of the general problem —if one mixes a number of electrolytes together in any proportion, what reactions will occur? By a discussion similar to that preceding prop. 24, one recognises easily that— (83) Bodies possessing the smallest coefficients of activity are most likely to be formed at the expense of opposite bodies. § 9. Applications of the foregoing paragraph. In practice the case which most often presents itself is that of two electrolytes, whose four ions are different, put to react on each other in a slightly active solvent {most commonly water). We will consider some important special cases, Casz 1. The two electrolytes are a very active acid, and the salt of a less active acid. Let the initial quantities be m and 1. If no water were present, the equation of equilibrium would be— @—t) =f) ab = 2 By ame 8 wt enn i B28 But, by reason of the presence of water, the salts, of which the quantities will be 1-2 and z, get into equilibrium with the water and their respective acids and bases. So minute quantities are decomposed by the water, and the quantities 1—x and x will be a little diminished—especially 1—., the salt of the less active acid. Let us write these so reduced quantities— Piel rgnal = vy. Similarly the quantity of reacting acids n—x and a will be a little increased, especially the latter. Call the actual quantities— A (n—2) and pax. - Calculation indicates that the greatest of the quantities y and W, A and p, does not differ appreciably from 1 unless a6 is excessively great in comparison with By. So, writing yA/py =r, we have proved that +1 if By is comparable to ad. If, on the other hand, ad/8y is very big, r will differ from unity, but still r* ad/8y will be enormously great, and hence in the equation— (n— 2x) (-a)e r= x . it is still necessary to suppose x almost equal to n or to 1, whichever is least. The role of the water consists in delaying the process a little, and can, from a broad BB2 372 REPORT—1886. point of view, be neglected. The same can be said of any other solvent of very’ small ‘active mass.” We are, then, in a position to assert the following pro- position :— (84) More active acids displace less active acids from solution of their salts. This is the proposition which, valid for bases also, is found in § 5 to agree so well with reality. [To avoid the appearance of verbal obviousness in this statement, we can remember that by ‘more active’ the author means ‘having a higher molecular conductivity.’ ] Case 2. Both electrolytes are salts very little decomposable by water. In this case the water may of course be neglected, and a8 nearly equals By; so from equation (24) one perceives that x has a magnitude comparable to »—2 or 1-2. Thus a sensible partition of the bases among the acids will be effected. (35) If two salts, of which the four ions are different, are dissolved in water (or any other solvent), the two other salts possible will form to such degree that their amounts will be comparable to the amounts of the primitive salts, when the four salts are not notably decomposed by the solvent. This proposition, very often verified, expresses a general opinion accepted by chemists. (See Berthelot.) Casz 3. If, on the other hand, one of the four possible salts—say that with the coefficient B—is to a high degree decomposable by the solvent (which is the case if it be composed of a feeble acid and a feeble base), but none of the others, an equilibrium will establish itself between this salt, its acid, its base, and the solyent, in such a way that only a certain fraction, *, remains as a salt in the Pp system, of the quantity which would be found if the salt were not decomposed. (2a) takes the form— (n—2)(1—z) ad = = By. So x will increase with p, that is to say— (86) In solutions of two salts, of which one is composed of strong acid and feeble base, the other of feeble acid and strong base, the strong acid unites by preference with the strong base, leaving the feeble base to the feeble acid. This latter salt ts naturally in great part decomposed by the solvent. This proposition has been experimentally proved by M. Berthelot (p. 712). Casz 4. If two feeble acids have the same base, M. Berthelot believes he has proved that a sensible partition is effected. According to what has just been said, this ought to be a special case of 1, so that if the acids are almost equally strong a partition occurs ; if, on the other hand, one of them is much the stronger, it seizes: on a portion of base incomparably the larger. The work of M. Berthelot gives examples of both cases. Thus a partition occurs between hydrocyanic and boracic acids; while the phenol of the phenate of potassium is displaced by boracic acid. § 10. Influence of acid salts. Salts called ‘acid’ are in general completely decomposed by water in sufficient quantity. According to M. Hittorf, acid phosphates are exceptions. Nevertheless, we have proved that NaH,PO, is partly decomposed by great dilution (see Part I. § 19). : The ions of acid salts are on the one hand a metal, and on the other the rest of the molecule. If, then, one mixes sulphuric acid with, say, sulphate of soda, a portion of NaHSO, is formed. But NaHSO, behaves as any other salt, ze.,, ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 373 its Hisnot anion. So that the part of H,SO, contained in NaHSO, has no effect, z.e., is totally inactive. Thus equilibrating systems are set up which do not agree with calculations based upon the coefficient of activity of H,SO, above given. And an equivalent of an acid-salt-forming acid (such as sulphuric, oxalic, &c.) cannot completely displace an equivalent of a more feeble acid from its salt, as prop. 33 asserts. [References to Berthelot. ] The calculation of the relative quantities of electrolytes contained in a system where acid salts occur goes on in the manner indicated above. Only it is necessary to observe that if the acid is r-basic, and if an acid salt is found in which o hydro- gen atoms of the acid are replaced by a metal radical, it loses, for each equivalent of acid salt formed, r/o equivalents of acid. So equation (2) becomes— (1-2) n=") a3)= (+2) (p +2) By, where n is the number of equivalents of acid added since the commencement, and 1, p, g are the corresponding quantities for base, water, and salt. If several salts (acid and neutral) form simultaneously, the calculation will be more complicated, as is seen most clearly by an example. Suppose one has at the beginning x. H,SO, and 1.KCl1; let there be formed «.K,SO,, y.KHSO,, and some HC]; the equation (2a) will take the form— (l-a-y) (n—x-2y) ad = (@B+y8’) (ex+y)y, where a, 8, 8’, y, 6 are the coefficients of activity of KCl, 4K,SO,, KHSO,, HCl, and 3H,SO, respectively. Between x and y there is a relation which is also a function of the quantities present in the equilibrium of free acids, neutral salt, and solvent, a relation of which the form still remains to be determined by experimental methods. § 11. Equilibrium of heterogeneous systems. [By ‘heterogeneous,’ Arrhenius means systems out of which one constituent is separated from solution in either the solid or gaseous form, and so removed from action to whatever extent it is insoluble. He quotes from Berthelot and Williamson about the formation of precipitates by double decomposition, and the continual postponement of equilibrium by the dropping out of one consti- tuent. He then considers a system of four bodies, I,J,, I,J,, 1,J,, 1,J,, of which one (say the last) is but slightly soluble. A constant quantity, ¢, of this remains in solution, however much of it is formed-or destroyed (time being allowed for pre- cipitate to re-dissolve ad lib.). Then, a, 8, y, 5 being the respective coefficients of activity, and x the amount of I,J,, and of I,J,, formed from an original one equivalent of I,J, and any amount ‘of I,J,, the equation (2A) is— a(1—2) cd3= 2° By. So x has a magnitude depending on ¢, and if ¢ happen to be zero, x vanishes. ] We have thus given an analytic proof of the law of Berthelot, (87) Zf of four bodies, (1,1), (1,2), (2,1), (2,2), one of them (2,2) has such physical properties that it separates wholly or nearly so from the system, this body (2,2) and its conjugate (1,1) are formed, to the exclusion more or less entire of the, opposite bodies, (1,2) and (2,1). If more than one substance is insoluble the equation may be, either a’By = cc’ad, e’xBy = c(1—2)ad. 374 REPORT—-1886. § 12. Consequence of the variation of the activity-coefficient im homogeneous systems. [Since provisionally Arrhenius supposed the coefficient of activity to be identical with molecular conductivity, he goes on to consider the effect of its varying with pressure and temperature as conductivity does. Pressure-variation he considers nil, or unknown, Temperature-variation he considers linear, 1 + dt. So he writes (24)— (1-2) a(1+8,t) (n—2) 8(1+,t) = 28 (14+4,t) y(1 + bt), but then says that the 6 are about equal for all salts and for all bases, and fairly equal for all monobasic acids; so the temperature terms cancel each other in pairs nearly ; and he states the laws. | (88) The equilibrium of a homogeneous system is independent of pressure. (89) The relative quantities of four bodies, ike two acids’ and two salts, or two bases and two salts, or four salts, in a system in equilibrium, only vary very slightly with temperature. The first is in accord with Bunsen and Berthelot; the second with Ostwald, who has verified it between 20° and 100° for HCl, HNO, and two salts of these acids with a single base. He has further shown that these two acids have the same activity between these temperatures by letting them act on calcic oxalate.” M. Ostwald has also determined the relative coefficients of affinity of different acids with regard to the same base. He let two acids act simultaneously on a given base—as, for example, KHO, MgO, &c. The acids employed were HC], HNO,, and H,SO,. The term ‘relative coefficient of affinity’ expresses the ratio between the fractions of the base which the two acids seize. If one mixes KNO, with HCl, one equivalent of each, there will be formed x equivalent of KCl and 2 of HNO,, and there will remain (1—wx) equivalents of KNO, and of HCl. The coefficients of activity being B, y, a, 6, respectively, x is given by the equation— (1—2)?ad = 2” By, and so the relative coefficient of affinity of HCl : HNO, is— x ad ® l—« WAG »): If instead of potassium one uses sodium, y and 6 remain, but a and # change. Q, however, need not change unless a’/8’ is different from a/8. (If acid salts are formed, a modification is necessary.) Molecular conductivities given above (§ 5) make one suspect that changing a base from KHO to ZnO or MgO will diminish the value of Q for HNO, : H,SO, and for HCl : H,S0,. For the rest: because the activity-coefficients of HNO, and HCl are about equal, and the same for salts formed from these acids, their relative coefficient of affinity ought to be nearly 1, whatever the base on which they are allowed to act. Here are Ostwald’s numbers :— Table of Relative Affinities. Base 2HNO; : H.SO, 2HCl : H,SO, HCl : HNO; K 2-00 1:94 ‘97 Na 2:00 1-92 96 NH, 1:88 1:81 ‘96 Mg 1:76 1-74 ‘99 Zn 1-61 1:53 95 Cu 1-44 1:40 ‘97 1 Except H,SO, and H,PO,. 2 Ostwald, Journal fiir praktische Chemie (1877), T. 16, p. 385. —— ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. Bic In a word, we believe experiment has verified the following rule deduced from the present theory :— (40) If an acid HR acts ona salt MR’, and tf a and B are the activity- coefficients of the salts MR’ and MR, the coefficients of relative affinity between the acids HR and HR’ vary almost proportionally to the square root of the quotient al. In § 13 of the first part we remarked that the molecular conductivities of different salts-approach each other, in such a way that they would seem for extreme attenu- ation to advance towards a common limit. It follows that the quotient a/8 approaches more and more to unity, and that the different values of a/8 become equal. This is why the relative affinity Q becomes more and more constant as dilution increases—a relation Ostwald thinks he has already perceived with dilutions less extreme. The activity-coefficients of acids and bases also approach equality as dilution increases. (41) Consequently the coefficients of relative affinity of acids, approach more and more to unity as dilution increases. M. Ostwald has also on this subject made some measurements which confirm the justness of the above proposition. His researches on the magnitude of the coeflicient of relative affinity of H,SO, indicate that at extreme dilutions this coefficient is ‘almost equal to that of HNO,, at least it rises to ‘9’ (that of HNO, being 1), while at moderate dilutions it is ‘5 or less, To the invariability of Q for acids and bases M. Ostwald adds a fact of great importance. The molecular conductivities of feeble acids and bases increase rapidly with dilution, z.e., the value of 6’ in weak solution is much greater than that of 6 in strong; so Q increases also, if we compare either of them with a strong acid or base, which is nearly unaffected by addition of water, for— Q= RE 28 for small dilution, By Q’= J a for large dilution. iy, Hence— (42) The relative affinities of feeble acids and bases (compared with a strong acid or a strong base) increase considerably as dilution goes on increasing. This is the reason for not attributing to these ‘coefficients of relative affinity,’ or ‘ avidities, as M. Thomsen calls them, a too great importance. By believing them constant one may seem to incline strongly towards regarding them as funda- mental numbers. Besides, the determinations of them by different workers do not agree well with each other. (48) As the activity coefficients of different acids change a little unequally with temperature, the relative affinity of two acids ought also to vary with temperature. Thus the activity-coefficient of H,SO, increases more slowly than that of monobasic acids (HCl or HNO,), whence it evidently results that its affinity, relative to either of these acids, diminishes as the temperature rises. We can give only a rough calculation. The temperature-coeflicient of conductivity for HCl or HNO, exceeds by 4 per cent. that of H,SO, at 20°C. ; so Q, which is proportional to square root of conductivity, will vary by about 2 per cent. per degree at this temperature. The temperature-coeflicient for H,SO, is still less at higher temperatures, so its relative affinity ought to diminish faster at these temperatures. Experience agrees with this as well as one can expect. * an Ostwald has found the following figures for the relative affinity of HCl to EN At 0° C. Q 1:90 At 40° C. Q = 2:02 sp ee BELA 2:00 yy OOP Cr Qa) Wak Between 0° and 40° Q varies about °15 per cent. per degree, while rough calculation indicated ‘2 per cent.; at higher temperatures the variation is greater, as expected. 376° REPORT— 1886. On the other hand, for HCl: HNO,, Q is almost constant, only varying from 1:00 to 1:02 between 0° and 60°. A great part of the cited observations (those on H,SO,) have been explained by Ostwald as due to the formation of acid salts at moderate dilution. We do not wish to deny this as a vera causa. We have already, in § 10, shown that the coefficient of activity diminishes for this reason. So naturally Q diminishes too. Nevertheless, it is difficult to explain thus the variation of Q with tempera- ture. It seems much more reasonable to admit the explanation given above. Finally, we will consider what ought to happen to a salt solution if its tempera- ture rise. For this it is necessary to observe-that the temperature coefficient of a concentrated hydrate is much greater than that of a weak solution. Thus, accord- ing to M. Kohlrausch— For sulphuric acid, at 99:4 per cent. concentration, 6 = ‘0426 Aoi ” ” ” ”? 6=-0121 For phosphoric acid, ,, 87:1 5 s 6=:0874 Ay ES ES b=-0099 For tartaric acid, ,, 49°53 ,, b=:0268 > SD) oy i 6=:0186 For caustic potash, ,, 41:7 5, i 6 = 0282 a PUM AO LS «.,, ie b=:0188 For soda, SZ 35 i} 6=:0710 ” » 261 ” ” b= "0195 For ammonia, GHG L,, 3 6=:0303 ” » Ol ” ” b= 0247 As this rule is without known exception, it seems permissible to attribute to water, which is also a hydrate, a coefficient much surpassing the coefficients of dilute compounds (which latter coefficients are almost equal among themselves). Some figures of Ayrton and Perry (Proc. Phys. Soc., II. 178[1877]) tend to confirm this. Similarly, the coefficient of a salt solution is sensibly greater than that of a hydrate. Looking, then, at the equation of equilibrium of a saline solution— (p+2)x2a6 (1+06,t) 1+0,4) = A-2) By 1+86,t) (1+8,2), we see that 6, and 0, are bigger than 4, and 6,,and therefore that the value of 1 —« obtained from it will increase with ¢. But 1—w signifies the amount of salt decomposed, so— (44) The quantity of salt decomposed in a solution ts increased if the tempera- ture of the solution rises. This will be true also for other electrolytic solvents, according to the law of Hittorf (see § 4). One may imagine that this important law can be otherwise deduced from the idea of a dissociation of salt molecules. True, physics show that at high temperatures the movements of molecules are more vigorous. But this does not point out why water then attacks salts more strongly. One often slurs over these difficulties by saying that heating (as well as dilution) brings to the solution a foreign energy opposed to chemical action. But what then is the import of chemical laws if they can be annulled by causes which never disappear completely, and of which one does not know how to calculate the effect ? The above lawis so generally adopted, and verified by a crowd of cases so enormous, that it is not necessary to cite any of them. § 13. Consequences of the variation of the coefficient of activity and of solubility in heterogeneous systems. The influence of the variation of the coefficient of activity is much greater for heterogeneous systems in equilibrium than for homogeneous ones. The equation (2a) has the form— (l—z)a.ci =2°By, where c is the quantity dissolved of a slightly soluble or gaseous body, (1 — x) the 1 Pogg. Ann., T. 159, p. 233; and Wied, Ann., T. 6, p. 1 (1876 and 1879). ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 377 quantity of its conjugate body, and x the dissolved quantity of its opposite. The coefficients of activity are 5, a, 8, and y, respectively. Let us first examine the influence of pressure. If the body whose mass is cis a solid, one may reckon that pressure affects nothing, and so— (45) A system heterogeneous with regard to a solid is independent of pressure. This proposition is in full agreement with fact, according to the researches of M. Bunsen (Liebig’s Ann., T. 65, p. 81, 1848). If, on the other hand, the ¢ body is a gas, c will be approximately proportional to the pressure of the gas in question on the surface of the solvent. Soif this pres- sure is zero,2=0. This case is realised if one lets the gas escape from the solvent as fast as it is produced. If the pressure increases, ¢ increases also, For this reason the opposite bodies (whose masses are z 8 and wx y) will increase, and the con- jJugate bodies will diminish. Such a phenomenon has been observed in a lot of cases. If, for instance, one of the opposite bodies is also a gas, as (for instance) when HS acts on an alkaline carbonate, one has the equation— (l-2z)a.cd8=€cB. xy. By giving to the pressure of H,S a sensible value, and by separating the carbonic acid which is liberated [e.g., by means of a continuous stream of H,S], one finally arrives at the result that c’, and therefore also 1—.z, are zero, z.e., that all the carbonate will be transformed into sulphide. Vice versd, by leaving to c’ a sensible value, and decreasing ¢, one could displace the H,S of an alkaline sulphide by CO,. Nevertheless, in the majority of cases the mass of gas dissolved is small in comparison with other matter dissolved. In this case x, that is the quantity of opposite bodies formed, will be insignificant, so that the influence of the gas on the ‘system is not notable. Thus, we cannot in general observe changes of equilibrium produced by the presence of gas, unless the dissolved quantity of the opposite body is very small. This case is realised if the body is either gaseous or but slightly soluble, and it has been considered. But in the second case, one could perceive the influence of the gas, for the products due to its presence would precipitate them- selves and disappear from the system. The precipitations of metallic salts by H,S is a well-known example. An influence, analogous to this of pressure, is exerted by temperature if the body with regard to which the system is heterogeneous is solid. The solubility of solids increases with heating. So e and 2 increase, while 1—z, the quantity of conjugate body, diminishes. This conclusion has been verified by numerous experiments. One finds many in the works of M. Ostwald, who has studied the phenomena accompanying the solution of some oxalates (CaCO, or ZnC0,0,) by an acid. M. Ostwald expresses the said conclusion thus :— (46) The effect of a rise of temperature on the quantities dissolved by a given acid at constant dilution is always to increase them. Another way of increasing the dissolved quantity, c, of a slightly soluble body is to increase the volume of the solution (¢.e., to add solvent). In this case one increases 8 and y also, as well as a. At the same time solubility can be diminished by diminution of concentration, as we shall soon see. But in most cases these Se obing influences cannot compensate the increase of c by augment of volume. o— (47) An increase of solvent encreases the body opposite to, and diminishes the body conjugate to, the solid with regard to which the system ts heterogeneous (if the perturbing influences are not too great).— Ostwald, J. fiir pract. Chemie (1881), T. 23, p. 517, and T. 24, p. 486. [The author then goes on to consider these ‘ perturbing causes.’ He quotes examples where the solubility of one substance in water has been shown to be increased by the addition of some other salt. He explains this phenomenon on his theory, and holds that the theory of Guldberg and Waage is insufficient to account for it, and, moreover, that it is not in agreement with the numerical results of Ostwald. ] 378 REPORT—1 886. § 14. Action between liquids and solids. [The author claims even for solids a certain electrolytic conductivity, and hence a certain, though very small, coefficient of activity. It is thus necessary for completeness to consider the action between liquids and insoluble solids. But inasmuch as the activity of even a trace in solution is much greater, because spread all through a liquid, than the action of a limited area of surface can be, he says the latter may be safely neglected, and states the law ]— (48) Ifa system is heterogeneous with respect to a solid body, of which, never- theless, a very small part is dissolved in the surrounding liquid, one can neglect the reactions which occur at the surfaces of contact between liquid and solid. § 15. Velocity of the reactions. [In accordance with a previous section the velocity with which I, J, and I, J, are formed (or with which I, J, and I, J, are destroyed), z.e., the velocity of the reaction, is— K(q@B.py—ma.nso). The author applies this to etherifications, where the water, alcohol, and ether have insignificant coefficients, the acid being the only active body. In this case the velocity is proportional to By, and so simply to the activity of the acid used, being quicker with nitric than with acetic. | § 16. Calculation of numerical examples. The coefficients of activity being not quite constant, according to the first part, slightly different numbers must be used for higher concentrations. § 17. Conservation of the type, and predisposing affinities. [Remarks on reactions among non-electrolytes, and on the behaviour of K,FeCy, with reference to Berthelot’s hypotheses on ‘conservation of type’ and ‘ predis- posing affinities.’] § 18. Molten electrolytes should behave just like others. § 19. Cases to which Berthollet’s laws are not applicable. M. Berthelot cites some of these cases. They can be put under two general heads. Hither a feeble hydrate is unable to displace a stronger hydrate, although one of the products of displacement is but slightly soluble, or a volatile acid (HCl and HNO.) partially displaces another acid (H,SO,), although this acid is not volatile. The first case is represented by the formula— (l—2)?ad = x*By < &By,4 where the feeble hydrate and the salt of the strong hydrate are present in equiva- lent quantities (originally 1), and where cis the soluble quantity of the slightly soluble substance. wz is the quantity of this substance formed, but as 2 is less than ¢ none is precipitated. One may write the inequality, a fortiori,— (l—c)? ai < By, or— Cc ad. To > By’ so if this inequality is satisfied there is no precipitate. a belongs to the feeble hydrate, 8 to the strong, 6 to the salt of the latter, y to the salt of the former (the slightly soluble substance). a6/y is in general pretty small, so c may be very small and yet no precipitation occur. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 379 As to the second case, no HCl escapes, and so the system is really homogeneous, and a straightforward partition occurs. We believe we have proved that objections made to the theory of Berthollet are avoided by the theory here presented. § 20. Production of heat in chemical reactions. As we know, M. Thomsen considers that all bases, if they exist in the form of dissolved hydrates, generate the same quantity of heat when dissolved in the same quantity of an acid. This he calls ‘saline thermo-neutrality.’ On the other hand, all acids do not generate the same heat when united to a given base—a circumstance which has appeared very odd to thermo-chemists. After what we have just said, however, it appears to me possible to explain it. It is evident that the thermo-chemical parity between two hydrates cannot obtain unless both are in the active state. In the inactive state analogous compounds do not play the réle of hydrates (acids or bases), since they cannot unite to a hydrate of any other nature (of contrary sign) and form water and salt. So instead of supposing, as M. Thomsen does, that the hydrates are in a ‘forme dissoute,’ we suppose them to be in the active state. After that we put forth the following very natural hypothesis :— The chemical process, by reason of which a system of one equivalent of actd (active) and one equivalent of base (also active), transforms itself into a new system, consist- ing of a salt (not complex) and water, is accompanied by the same heat-production independent of the nature of the acid or base. The different processes which go on during the neutralisation of an acid or a base (both supposed partially inactive) are the following :— 1. Neutralisation of the active parts. 2. Transformation of inactive parts into active ones. 3. Neutralisation of these new active parts. 4, Formation of molecular complexes of the salt produced. 5. Possible solidification of the salt. Between these five processes it is the sum of the heats produced in 1 and 3 per equivalent of salt formed which ought to be constant, according to the above hypothesis. The existence of the processes 2, 4, and 5 explains how it happens that the actual heat-production can be different in different cases. {Omitting 5, and considering 4 as small, the author points out that No. 2 pro- cess is of least importance for strong acids and bases, and accordingly that for these the heat-production may really be nearly constant. But for weak acids and bases a good deal of heat is consumed in the No. 2 process. For remember that ‘strong’ means, in his view, ‘having a high percentage of active molecules,’ and ‘weak’ means ‘ having very few active molecules.’ Moreover, since a molecule’s activity is allied with, or equivalent to, its dissociation, it is very natural that its production should be a heat-consuming process. Slight residual differences he explains by No. 4 process, considering sulphates and acetates as more complex than chlorides, nitrates, &c., and makes the following statement :—] (51) Increase of complexity is accompanied by production of heat. (52) Transformation from the inactive to the active state is accompanied by absorption of heat. (53) During neutralisation a feeble acid or base generates in general less heat on the whole than a strong one. Since now for salts it happens that the activity is smaller as the complexity is greater (see § 2), and the formation of molecular complexes is (by 50) followed by a generation of heat, it is necessary that for salts also the travsformation from inactive to active state shall be accompanied by heat-absorption. But, by prop. 33, bodies endowed with the smallest activity have the greatest chance of being formed. Thus it follows that— 380 REPORT—1886. 54) In chemical reactions among electrolytes those bodies are in general : ee ve Sera ge formed in greatest quantity, the formation of which is accompanied by the greatest heat-production. This is the ‘ principle of maximum work,’ modified. It is valid im general, not always. [Neglecting now the above process 4, the author points out that process 2 has two parts, one concerned with the acid only, the other with the base only. Call these 2, and 2,. Processes 1 and 3 he considers all along as giving a constant thermal effect ; and so he splits up the total heat-production H, by all the processes, thus— H—-h, = (A, + hs) + hoa + hy, and states—] (55) The heat produced by the neutralisation of an acid A by a base B (less heat of possible solidification) is equal to a constant, plus a term de- pending on the nature of the acid only, plus another depending only on the nature of the base. This has been verified by the experiments of M. Thomsen. p is calculable from the following data : the decomposition products of 4 milligramme of water on two platinum plates, each one metre square, give an H.M.F. of one Daniell; consequently, knowing L, p, E, and measuring C? with a dynamometer, it is possible to calculate the true value of R. Or, by arranging that the polarisation coefficient p is equal to mL, all disturbance vanishes, and the resistance can be measured quite simply by a bridge method. Unless the question of electro-chemical capacity be thus considered, and either eliminated by calculation or proved to be negligible by experiment, the presumed advantage of alternating currents in deal- ing with electrolytic resistance is illusory. O. L. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 385 cases ; on the other hand, he had six times as many alternations of currents per second, so the self-induction of his rheostat must be greater than that of mine (§ 3). On quite other grounds, Kohlrausch’s method is preferable. I may also say that Kohlrausch used a galvanometer for measuring higher resistances. *2. Secondly, concerning your remark on subtracting the conductivity of the water in order to find that of the dissolved salt. This mode of calculation I use, not only because it corresponds with later established “laws,” but also on true @ posterior2 grounds (which indeed the reader of your critique cannot guess; cf. Pt. I. § 9). It would, however, to my mind, be little logical not to show that the rule corresponds also with the general laws, according to my apprehension of them. So I cannot understand your objection to this paragraph. The law of divided circuit is, so far as I know, really true when two electrolytes are mixed. According to my hypothesis, the conductivity of a solution is equal to the sum of the number of ions, each divided by the friction it experiences against the fluid. This view leads necessarily to the law in question, and it is also a necessary consequence of the Williamson-Clausius hypothesis. I regret I cannot enter fully into this here. I have, moreover, applied this rule throughout my memoir on conductivity of mixed solution with, so far as I see, complete success. You say quite simply, “ which is untrue.” I wish you would tell me of any well-established fact against it. I am of opinion that there exists no basis for the opinion that the law of divided circuits does not apply to dilute solutions.' ‘3, Thirdly, “that the conductivity of water itself remains unaffected by the presence of a foreign body ; which is improbable.” ‘It appears as if you meant that the conductivity which Kohlrausch and I have proved to exist in our distilled water is really the conductivity of water. That my experiments contradict this is indubitable, and Kohlrausch also attributes it to traces of saline impurity. Reaction-velocities give a pretty safe judgment on this subject. I have thus pretty clearly shown that there are salts which cause the greatest part of this conductivity (Part I. § 11). The probable effect of the foreign body is to take much of the water from the said salts (cf. my memoir on conductivity of mixtures), The salts, however, change their molecular conductivity very little with great dilution; and so the apparent conductivity of water does remain very nearly unaffected by the presence of a foreign body in very dilute solu- tion. I could say much more on this if time permitted. ‘4, Fourth, “ The first approximation to the relation between & and m is that made by Kohlrausch, viz., that the two are proportional. This is roughly true for very dilute salt-solutions.” ‘For example, copper acetate (see Part I. p. 40) has the following :— smey pal, Ses BEY 276’ 200’ 1254’ 6586' -8 & =320, 512, 671, 740,times10 m ‘ Again, copper sulphate has, according to Kohlrausch (p. 196 of his last memoir), the following:— — m= ‘1 05 ‘01 :001 0001 00001; % 988 424 479 675 950 1062 1086. ‘You can find still better examples among mercury salts! ‘These numbers, according to Kohlrausch’s formula, should be the same; so the correspondence between formula and fact seems to me not “ roughly true,” but altogether futile. (The dilution-exponent is in every case much more constant ; though I build nothing upon the fact.) ‘That for extremest dilutions, under ;;3;,, the molecular conductivity is fairly constant, although even then probably not for mercury salts, I also have shown ; since in these cases the dilution exponent rises to 2. 1 See footnote on pp. 358, 359. If Dr. Arrhenius did not mean that the law was deductively proved by him (in § 15) for all cases, my criticism does not apply; ex- cept, indeed, to his mode of statement. O. L. 886. co 386 REPORT— 1886. ‘I set myself the problem to find out how much the resistance actually increased when a dilute electrolyte had its volume doubled by addition of water. (If Kohl- rausch’s formula were true, it would be simply doubled.) Thus I started free from hypothesis. The observed ratio of increase of the resistance I called “the dilution- exponent.” Since it changes very slowly with concentration, one need not ascertain it by making every dilution from | to 2, but can quite well obtain a mean value of it for a greater range (say 1 : 6:08) ; and the calculation of the mean number then proceeds on purely arithmetic grounds without any special hypothesis. I hold strongly, therefore, that my method of calculation is absolutely correct for mean values; and that I have always meant mean values is quite clear from page 34 et seg. ‘The number is by no means a constant. I speak continually of its variation, and have tabulated the variations in Table B. I could not make its variability clearer than I have done. I have taken conductivity as the fundamental quantity instead of concentration, because one is always much safer in determining its abso- lute value by ordinary means. You think it would have been better to tabulate r instead of 2”; this is a matter of taste. The dilution-exponent is easy to define physically ; 7 is not. Besides, one can more easily form a mental image of its meaning. Not only Bouty, but Lenz also, and Ostwald, have discussed the change of resistance on doubling dilution. «5. “Kohlrausch and most authors suppose that k/m is constant for extreme dilution.” This he does without reservation for solutions of no extraordinary wealk- ness, and he thence calculates &/m for extremest dilution, whereby he several times gets incorrect values (too small).1 The hypothesis is, however, quite natural, and I have always regarded this idea of Kohlrausch as most valuable; and I sought consequently to apply this idea, and to show how to explain apparent ex- ceptions to it. I never sought to “label” the statements (1), (2) and (8) as laws of nature, but say definitely: ‘The above conclusions are deduced from ideas which are in full accord with all known facts, and consequently they have the same degree of exactitude as those ideas accepted by all the world” (Part I. § 15). It is quite certain that the conductivity of water is very feeble, and there is no reason for denying that molecules may be independent of one another in very weak solutions, since they collide so seldom, I have sought to explain why in practice the mole- cular conductivity is not constant even in utterly weak solutions. I have given two explanations :—Ist, that the water used contains traces of ammonium salts (especially Am,CO,, not dissolved glass as you write ; a fact more lately proved by Ostwald), which explains the decrease of molecular conductivity of hydrates; and 2nd, that molecular complexes are formed ; a hypothesis which is introduced into so many other subjects that one need feel no difficulty in employing it. (This view a reader of your exposition will hardly attain.) ‘6. That the last work of Kohlrausch contains as you say incomparably better experimental data (especially more accurate) is true enough. But without my data I could not have formed a coherent picture of the whole. Besides, Kohlrausch’s work has in no way caused me to alter any theoretical views, but has fully con- firmed me in them. ‘It is the highest problem of the natural philosopher to link together facts into a connected chain. I had expected a criticism from you to take this view. I concluded that you were of this opinion from your essay on the seat of voltaic E.M.F.; yet you abandon it in your criticism of the first part of my memoir. ‘ As to the second part, I am very glad that you have everywhere appreciated my views, and represented them in a more complete manner than I could have hoped. _ Just a few notes. ‘7, With regard to your remark on (14), I may say, in explanation, that almost all chemists attribute the reactions of ammonia to a small portion of NH,HO in it, which so soon as consumed is generated anew by equilibrium between H,O NH, and NH,HO, so that ammonia behaves chemically just as if it consisted of nothing but NH,HO. In Thomsen’s and Kohlrausch’s experiments, on the other hand, the properties of the chief quantity, which consists of NH,, play the greatest part. 1 These remarks refer to my 1879 essay.—F. K. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 387 £8. To § 4 you say that the Williamson-Clausius hypothesis would have been soon abandoned if it had not corresponded with the fundamental laws of Faraday, Richter, &c. So far as I know, no one has hitherto raised the question; besides it is of very great importance to deduce various laws from a single point of view. ‘9, As to law (20), which is still very discussable, I have had no opportunity of going off into digressions in the treatise, but refer to Hittorf and Bleekrode. I treat the whole question as open, and share also the view that the conductivity of these bodies has been proved to be mainly, though not exclusively, due to the presence of saline impurities, One is only able at present to decide matters like this on a chemical basis. ‘With compliments, &c., ‘Svante ARRHENIUS. * Wiirzburg, November 1886.’ Viscosity and Conductivity. [The following letter from Dr. ARRHENIUS, though of late date, so directly bears on subjects referred to by Prof. Kohlrausch (p. 343) that tt is best inserted OL Om: WURZBURG: January 4, 1887, Some time ago I thought of publishing the numbers given below, which may have a certain amount of interest in elucidating the question as to the connection between conductivity and internal resistance. In discussing the question with Prof. Kohlrausch I have been confirmed in my hypothesis, and, in accordance as much with his desire as with my own, I send the following communication. In the subjoined table the names of the solutions examined (all of normal . strength) are set forth in the first column ; in the second column the conductivity (A) of these solutions (from Kohlrausch’s last memoir) ; and in the third column the viscosities (p) determined by myself. The fluids I investigated are identical with the solutions employed by Kohlrausch in his conductivity determinations. The numbers for the internal friction are given for 17:6° C., reduced to the internal friction of distilled water at 17°6° as unit. I cannot here describe the method of investigation, but may refer to the paper which I have communicated to Wiedemann’s ‘Annalen.’. The errors of observation probably do not amount to 0°5 per cent. _— A (Kohlrausch) (Arrhenius) p (Kreichgauer) KI 968 10-7 912 93 | KNO, 752 "956 “97 NH, Cl 907 ‘977 98 K Cl 919 ‘978 — Na NO, 617 1-051 1:06 Na Cl 695 1:093 1:08 2 K, 80, 672 1101 1:09 4 Ba Cl, 658 1/107 sila 3 K, CO, 660 2 1:142 1:15 Li Cl 591 1:147 115 2 Zu Cl, 514 1/189 1:18 4 Na, SO, 475 1-230 1:23 KC, H, O, 594 (1:258) —_ 2 Li, SO, 386 1:299 1:28 2 Zu SO, 249 1:362 1:35 = Cu SO, 241 1:368 — 3 Mg SO, 270 1:379 1:37 The numbers entered in the fourth column are some further experiments by Kreichgauer, assistant to Prof. Kohlrausch ; they may be in error to the extent of one or two per cent. The number for potassium acetate was not observed directly, cc2 388 REPORT—1886. but was calculated from that for a half normal solution on grounds which I cannot here set forth; it may be affected by a somewhat greater error than the other numbers, though not so great as to make the succession irregular or to account for the irregularity of the succession. As may be seen from these numbers, there appears to exist a certain relation between the internal friction and the conductivity of normal solutions, so that toa great extent the higher the conductivity the smaller is the internal friction. A detailed carrying out of this law is, however, impossible, since marked excep- tions occur. Of the seventeen salts examined five are exceptions, viz., KNO,, NaNO,, K,CO,, KO,H,O,, and MgSO,. The exceptional behaviour of NH,Cl as: compared with KCl may be only apparent. (It is not unlikely that when salts of lower conductivity are examined the exceptions may become more numerous and more strongly marked.) In the hope that my note, though inconclusive, may add a little to the material. . for discussion of a difficult subject, I subscribe myself Yours, &c., SvanTE ARRHENIUS. Electrochemical Thermodynamics. [Since submitting proof sheets I have been favoured with the following most interesting letter from Professor J. WILLARD Gisps.—O, L. | NEW HAVEN: January 8, 1887. Drar Srr,—Please accept my thanks for the proof copy of your Report om Electrolysis in its Physical and Chemical Bearings, which Ireceived a few days ago with the invitation, as I understand it, to comment thereon. I do not know that I have anything to say on the subjects more specifically discussed in this report, but I hope I shall not do violence to the spirit of your kind invitation or too much presume on your patience if I shall say a few words. on that part of the general subject which you discussed with great clearness in your last report on pages 745, ff. (Aberdeen). To be more readily understood, I shall use your notation and terminology, and consider the most simple case ossible. , Suppose that two radicles unite in a galvanic cell during the passage of a unit of electricity, and suppose that the same quantities of the radicles would give 6c units of heat in uniting directly, that is, without production of current; will the union of the radicles in the galvanic cell give Je units of electrical work? Certainly not, unless the radicles can produce the heat at an infinitely high temperature, which is not, so far as we know, the usual case. Suppose the highest temperature at which the heat can be produced is ¢”, so that at this tem- perature the union of the radicles with evolution of heat is a reversible process ; and let ¢’ be the temperature of the cell, both temperatures being measured on the absolute scale. Now Oe units of heat at the temperature 7” are equivalent to , f= Fy be units of heat at the temperature ¢’, together with Je tet units of mecha- t’’ nical or electrical work. (I use the term equivalent strtet/y to denote reciprocal con- yertibility, and not in the loose and often misleading sense in which we speak of heat and work as equivalent when there is only a one-sided convertibility.) Therefore the rendement of a perfect or reversible galvanic cell would be /} / / JGe on Es units of electical work, with Oe a units of (reversible) heat, for each unit of electricity which passes. You will observe that we have thus solved a very different problem from that which finds its answer in the Joule-Helmholtz-Thomson equation with term for reversible heat. That equation gives a relation between the E. M. F. and the reversible heat and certain other quantities, so that if we set up the cell and measure the reversible heat, we may determine the E. M. F. without direct measurement, or vice versd. But the considerations just adduced enable us to predict both the electro-motive force and the reversible heat without setting up ON BLECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 389 the cell at all. Only in the case that the reversible heat is zero does this dis- tinction vanish, and not then unless we have some way of knowing @ priori that this is the case. From this point of view it will appear, I think, that the production of rever- sible heat is by no means anything accidental, or superposed, or separable, but ‘that it belongs to the very essence of the operation. The thermochemical data on which such a prediction of E. M. F. and rever- sible heat is based must be something more than the heat of union of the radicles. ‘They must give information on the more delicate question of the temperature at which that heat can be obtained. In the terminology of Clausius they must relate to entropy as well as to energy—a field of inquiry which has been far too much neglected. Essentially the same view of the subject I have given in a form more general and more analytical, and, I fear, less easily intelligible, in the closing pages of a somewhat lengthy paper on the Equilibrium of Heterogeneous Substances (Conn. Acad. Trans.,’ Vol. III., 1878), of which I send you the Second Part, which contains the passage in question. My separate edition of the First Part has long been exhausted. The question whether the ‘reversible heat’ is a negligible quantity is discussed somewhat at length on pp. 510-519. On page 503 is shown the connection between the electromotive force of a cell and the difference in the walue of (what I call) the potential for one of the tons at the electrodes. The definition of the potential for a material substance, in the sense in which I use the term, will be found on page 443 of the synopsis from the ‘ Am. Jour, Sci.,’ vol. xvi., which I enclose. I cannot say that the term has been adopted by physicists. It has, however, received the unqualified commendation of Professor Maxwell {although not with reference to this particular application—See his lecture on the Equilibrium of Heterogeneous Substances, in the science conferences at South Kensington, 1876); and I do not see how we can do very well without the idea in certain kinds of investigations. Hoping that the importance of the subject will excuse the length of this letter, I remain Yours faithfully, J. Witiarp Gisss. Nove BY THE EDITOR.—It is perhaps hardly wise to comment on the letter of so great an authority without further consideration, but it naturally occurs to one to ask provisionally whether he is not regarding a galvanic cell as too simply a heat engine? Surely ifthe union of certain elements can generate ¢ units of heat when heat-production is all that is allowed, they can, under favourable circumstances, do Je units of (say) electrical work instead, quite independently of any considerations of entropy or of the temperature at which the heat might have been generated? In other words, is Professor Gibbs not assuming that in a cell the union of elements primarily produces heat, and secondarily propels a current, instead of (as may well be the case) primarily generating a current, and secondarily producing heat when that current is given nothing better to do? To this Professor Gibbs will doubtless reply : No, the highest temperature at which the heat could reversibly be produced, viz., the temperature of complete dissociation of the compound formed, is of the essence of the question, whatever be the mode of exciting the current. It is needless to point out the extreme interest and importance of such a view. oO. L. On the Migration of Ions and an Experimental Determination of Absolute Ionic Velocity. By Dr. OLIVER LODGE. What may be considered as the greatest step in advance since the time of Faraday in the subject of electrolysis is due to Professor F’. Kohlrausch. His idea of specific ionic velocity is obviously most im- 390 REPORT—1886. portant. The bases of it are his own experiments on conductivity, and those of Hittorf on ‘ migration’ or unequal concentration. Up to the present time the numbers given by Kohlrausch for the absolute velocity of different ions in centimetres per second have been deduced from theoretical grounds only, and the sole verification to which they have been subjected has been by showing that from them the observed conductivities and migration coefficients of a considerable number of solutions can be calculated (see, for instance, page 337 above). In a paper published last year! I indicated reasons for doubting the complete truth of the Kohlrausch theory as it stood, 7.e., for supposing it deficient in generality, and also initially suggested an experimental method suitable for examining the question, and for giving a direct determination of the absolute velocity of various ions, in a form apparently free from any hypothesis. | The method consisted in passing a current through an electrolyte con- tained in a uniform glass tube, and arranging some form of test substance to detect the position to which the ions had at any instant attained in their journey along the tube. The speed of any ion which lent itself to this mode of chemical detection could thus obviously be measured, provided disturbing causes could be excluded. The experiments I have made on this plan hitherto, though numerous, can hardly be regarded as more than preliminary—a good many diffi- culties, some expected, some unexpected, having turned up in the course of the investigation, as usual. Nevertheless, a fair approach to a satis- factory and accurate result has been in some of the later instances obtained, and, besides the experience, some of the results themselves are worth having. Let me first rapidly obtain the theoretical values of ionic velocity, in a complete manner, in order to distinguish the parts of the theory which are manifestly true from the parts which may require modification and development. Consider a unit cube of electrolyte, containing n* active molecules, v.e., 2° molecules actually engaged in conveying a current, and ignoring any inert molecules such as those of the solvent have (perhaps without reason) usually been supposed to be. Let q be the total charge of each kind of electricity possessed by the constituent ions of each active mole- cule, and let U be the velocity with which the two oppositely charged ions are being sheared past one another by the applied slope of potential — Then, if & is the conductivity of the unit cube, we have the follow- da ing couple of expressions for the intensity of current (7.e., quantity of electricity conveyed per second through unit area normal to the flow) :— First n?q* ”U, from simple notions of convection ; second i , from Ohm’s law. x Writing N for the number of monad gramme-equivalents of the active substance present in the unit cube, and 7 for the H.C.E. of hydrogen (that is, 1/y for the quantity of electricity corresponding to any monad gramme- equivalent), it is plain that Let, .-SN'”¢d. aa 1 Aberdeen Report, p. 754. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 391 So, equating together the above two expressions for intensity of current, we get eed nigu NU : ad n or, k dv n SS 7p a — Ca a i Sete (1) y being the intensity of current. Whence the arithmetic sum of the opposite velocities of anion and cation (w and v), when urged by a slope of potential of one volt per centi- metre, through a solution containing N monad gramme-equivalents of active substance per cubic centimetre and of specific conductivity k seconds per square centimeter, is U=utont x 00010352 x 108 ; w+v= 10352 centimetres per second .. . (2). So far the ground seems to me to be perfectly firm. We now proceed to apply this to special cases. To do this we assume, with Kohlrausch, first, that N=m, the quantity of salt in unit volume of the solution; second, that the ratios of the anion and cation velocities, w/v, are known for a number of substances from Hittorf’s classical migration experiments. On these two assumptions a table of velocities can be constructed. They vary, it is true, with k/m, but this number is fairly constant for very dilute solutions of many substances ; if it is not, the concentration must be specified. The latest determinations of Kohlrausch! give the following numbers for specific ionic velocities (in centimetres per second) in an aqueous solution containing one-tenth of a gramme-equivalent of salt per litre, the applied E.M.F. being 1 volt per centimetre. Cation... H KvOe NH, Na Li Ag@ 4Ba 4Mg 4 $2Zn v= -00300 00057 -00055 -00035 -00026 -00046 -00033 -00029 -00026 Anion ... OH Cl I NO, ClO, C,H30, w= 00272 -00059 -00060 -00053 -00046 -00029 Radicles omitted from this table, like SO,, PO,, &c., are intractable or anomalous. Now in the above calculation what is there hypothetical? Accepting for the present the direct Hittorfian view of migration, the assumption that N=m involves two hypotheses, viz. :— (1) That the added salt alone is the active substance, the solvent conducting none of the current. (2) That the whole of the added salt is equally active. On any dissociation view of electrolysis it could hardly be expected that when two substances are mixed one should be wholly inert, the other wholly active. It would seem much more probable, without evidence to the contrary, that the two substances should dissociate each other in some ratio or other, and that the conduction should be shared between them. If this be so, equations (1) and (2) still remain perfectly true, but it is not so easy to determine N, the amount of active substance per cc. It 1 See. memoir abstracted above, p. 337. 392 REPORT—1886. may indeed turn out to be proportional to m, the amount of salt added, but it is hardly likely to be exactly equal to it. Moreover, if two substances are active, we shall have to split up w into w, and ws, v into v, and v2, as well as N into N, and No. If m is the mass of salt contained in every gramme of solution, “ is the ‘ dissociation-ratio’ or ‘ activity-coefficient’ ! of the salt, and i er the dissociation-ratio of the water. And equation (1), written out fally, becomes— d N, (uw, +%)+N, (11+) =hn ee (3). The value of & to be used here is the simple straightforward conductivity of the whole solution. There is to be no subtracting of hypothetical water- conductivity in order to get at an inaccessible salt-conductivity ; the dis- tinction between known and unknown quantities is perfectly definite. By a complete quantitative electrolytic experiment, such as Hittorf first made, and Wiedemann and others have followed up, the four quantities Nu, N,v, Nous, N,v, can all be obtained ; but it is not possible thus to obtain the values 2, v1, Uo, Vo, separately, unless the dissociation-ratios N,/m and N,/1—m are known too. The mode in which I have begun to make complete determinations of electrolysis may be stated for the case of copper sulphate. The cathode vessel is in the form of a specific gravity flask with a long horizontal tube Fic. 1. neck, which has a con- striction at one place, to which it can be accu- rately filled, and an open mouth above the con- striction for the anode vessel to dip its beak into. The cathode can is be a piece of platinum 2 Full Size fused through the glass, or, more conveniently, passed through a stop- per. The anode vessel may be like a tobacco-pipe with the anode immersed in its bowl, and its stem recurved so as to dip into the mouth of the cathode vessel. Only one of the two vessels is to have measurements made upon it, and the cathode vessel is perhaps generally the more convenient. It can be kept immersed up to its neck in a bath of water at constant temperature, as in fig. 10. The course of the experiment is as follows :—Fill the cathode vessel with a standard solution, adjusting its level exactly to the mark at a known temperature; then weigh it. Pour a little more solution into its mouth, Fill the anode vessel also with the same solution ; arrange as suggested in figure 1, and pass a measured current for a known time, with a silver voltameter in circuit. Then remove the anode vessel, re- adjust the level in the other, and weighagain. Finally analyse the contents of the solution in the cathode vessel, and weigh the cathode deposit or voltameter plate. The necessary and sufficient data are these :— 1 See memoir of Arrhenius below, p. 364. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 393 1. Proportion of ingredients in original solution. 2. Initial weight of cathode vessel. 3. Final weight of ditto. 4 and 5. Any two of the following three things: the amount of Cn, or of SO,, or of free H,SO,, in the final solution. The object of the long tube is to be sure that the current shall have to travel through the unaltered original solution in some part of its course ; also to preserve uniform some liquid near the constriction. I was under the impression that this scheme of experiment was more complete than any that had been previously attempted, but I have since looked up Hittorf’s papers,! and found them very admirable. I do not say that nothing better can be done, but I have done nothing better yet, and therefore shall not at present rehearse the mode of treating the above data in order to extract from them their meaning, especially as it is long enough for a separate paper. Direct EXPERIMENTAL DETERMINATION OF ABSOLUTE IONIC VELOCITIES. Let us pass now from this rather laborious method of determining N,u,, N,v, &c., to a simple and direct mode of experimenting on the velocities u,v;, &c., themselves. It is manifest that if one can determinefor any substance, Nu by one method of experiment, and w by another, its dis- sociation-ratio N/m, which must be a very important chemical constant, is known instantly. One of the early forms of experiment for observing « and v was arranged thus :-— Two vessels, containing fairly strong sulphate of soda and baric chloride, respectively, adjusted to equal density, were joined by a longish tube full of dilute hydrochloric acid of small specific gravity (fig. 2). Acurrent from some twenty stor- age batteries was then applied, and the tube examined from time to time for the first appearance of a precipi- tate of baric sulphate. When everything went well the precipitate appeared as a fine ring Inside the tube, which rapidly filled up into a beautifully sharp thin disc or complete partition, and then grew in thickness, spreading out slowly both ways till it formed a solid plug and rather obstructed the current. The locality of the disc and the time of its appearance after starting the current were noted; but I do not here record these first results, be- cause they were very variable, owing to disturbing causes. One obvious disturbing cause is that of slight differences of level, produced either by earth-warpings and local pressures, or by evaporation. To diminish mechanical changes of level the two vessels were next arranged side by side, and the tube was bent double so as to have its ends close together and yet to afford a good length for observation. The level of the vessels was accurately adjusted, and the tube intro- duced with as little disturbance as possible,various devices, such as super- Fig. 2. 1 Pogg. Ann., vols. 1xxxix., xcvili., cili., cvi. 394 REPORT—1886. numerary tubes and stopcocks, being sometimes employed to assist this (fig. 3). : ; To diminish evaporation a layer of paraffin was sometimes put on each Fic. 3 vessel, and my assistant, has Mr. Robinson, hit on the happy device of connecting the two layers of paraffin by another and a much shorter and stouter siphon tube full of paraffin, so as to equalise the levels and, if possible, to keep them equal, and yet not to tap off any of the current by this supernumerary but almost. infinitely resisting path (fig. 4). We now got much more consistent results, and for a long time thought things were pretty satisfactory, so we proceeded to make numerous obser- nies vations, varying the character and Pea length of the tubes, the number of volts applied, the strength of the solution, &c. The difficulty of electric endos- mose is an obvious one, and it may be owing to this that the results of these experiments are not very concordant. Omitting minor corrections, however, and taking the measured ratio of the distances of the ring precipitate, from the BaCl, vessel eni, and from the Na,SO, vessel end of the tube, for all those experiments where a paraflin levelling tube was used, we get the average result that the ring forms 3'2 times as far from the BaCl, end as from the Na,SO, end (see p. 400). This may be recorded by saying that the Ba travels three times the distance that the SO, travels in the same time, or that Ba travels three times as quickly as SO,; a result which, though simple and definite, is probably incorrect. But it is possible to argue that what we are measuring is not this simple ratio of speeds but a more complex ratio depending on all the substances. Thus, consider the substances in action, Na, SO, | HCl HCl HCl | Ba Cl,, and pass the current from right to left. On Hittorfian principles, H travels to meet the SO,, and journeys the greater part of the distance between them; Cl also travels to meet the Ba. Call the true velocities of these four ions, h, s, c, b respectively ; then the position of the precipitate of the meeting Ba and SO, may be thought to really measure, not } : s, but be Cant Now, on Kohlrausch’s calculation, h=29,b=3°'3, c=5:3, s is not certain, but from Hittorf we may take it as roughly equal to the velocity of K, viz., 5'1; in which case bh_ 33x29 _ iar wao mm ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 395: I by no means press this probably accidental agreement ; and the true meaning of any results obtained by such methods as I have described I leave for the present open. On my cursorily mentioning these very preliminary results in a circular to the committee on Electrolysis, Professor 8. P. Thompson suggested using a jelly, and we at once tried it. One cannot use any strong acid with gelatine, for it seems to spoil it, but acetic acid serves; and the siphon tube was accordingly filled with an acetic acid gelatine jelly, which went stiff when cold. Agar-Agar jelly, suggested, I think, by Prof. Clowes, can be used with stronger acids. The use of jelly makes the experiment much less troublesome, be- cause there is now no difficulty in the manipulation, no special need for adjustment of the solution densities, nor danger from changes of level. One objection to it is, that, supposing the ionic velocities were deter- mined in jelly, they could not easily be compared with Kohlrausch’s numbers, which apply to weak aqueous solutions. There is of course no difficulty in determining the conductivity of the jelly and the slope of potential, as required in formula (1) ; but it is difficult to assign a value to N. The hypothesis that the solvent does none of the conduction, even though it be true for water, can hardly be pressed to include the case of a jelly of unknown and complicated constitution; especially as we found that the conductivity of plain jelly was actually considerably greater than that of dilute acetic acid ' (see p. 406). The endosmose difficulty is not got over by the use of jelly—in fact, it may perhaps be accentuated; and another and unexpected difficulty pre- sents itself. Gelatine swells under the action of the current and exudes from the tube ; but always in one direction only, viz., against the current. A cylinder of jelly an inch or two in length was ultimately protruded from the anode end of the tube; and cracks appeared in the substance of the jelly, of curious serpentine form, which underwent noteworthy metamorphoses. The position of the precipitate in these jelly tubes was not far from the middle of the tube, indicating that Ba and SO, travelled at nearly equal rates (see pp. 401 and 411). Second Series of Experiments. I next proceeded to another form of the experiment, where a detecting substance was placed in the tube so as to be able to follow the motion of the ions along their journey, instead of only noting their time and place of meeting. Various detectors were tried, but a simple and obvious one, able to show both anion and cation, is sulphate of silver. A jelly tube containing, besides acetic acid, a solution of sulphate of silver, was arranged to join two vessels, each full of baric chloride solution. When the current passes, the barium travels with it and causes a preci- pitate of BaSO,, which may be watched creeping on from point to point ; the Cl at the same time travels against the current and causes a precipi- tate of AgCl, which may be likewise watched. The poor solubility of Ag SO, is of no consequence, because it is only wanted to detect the ions, not to absorb them and stop their motion; hence, however soluble a _ ..’ In this connection see Dr. Arrhenius’ previous experiments on conductivity of jelly as detailed above, p. 344. 396 REPORT—1 886. detector is used, the amount of it put into the tube ought to be almost infinitesimal, or it will cause disturbance and prevent the full velocity of the ion being observed. There is some slight difficulty with a solid precipitate, as detector, when free liquid instead of jelly is employed: for its settling causes currents and convective disturbances—especially in the vertical ends of the tube. Fluid detectors, whose colour the ions change, are therefore in some respects better. Roughly examining the results obtained by the methods just described, one may say that they give the velocity of Ba through jelly, fora fall . of 1 volt per centimetre, as about ‘00012 centimetre per second; the | velocity of Sr is about ‘00015. The speeds of Cl, Br, and I are not very different from each other, and about ‘00024. This rough statement is merely to give a notion of the order of magnitude of the velocities obtained, and by no means represents the full deduction from the tabulated numbers. Experiments on Speed of Hydrogen. To detect the motion of Hydrogen Mr. Robinson devised the following arrangement :—We happened to have been using phenol-phthallein as a detector of alkali in some other quite distinct experiment, and so it was a _ handy substance. The jelly tube contains a little phenol-phthallein and a trace of common salt, just made alkaline enough with soda to bring out the colour. The solution in the anode vessel is H,SO,; in the cathode vessel the same, or sometimes CuSO,. (For details see below, under date August 17, p. 407.) The result is that SO, travels one way, and H, the other. As the H travels, it liberates HCl, and decolorises the solution. As the SO, travels, it also decolorises the solution by forming neutral Na,SO,. The velocity of hydrogen, for 40 volts applied to a 40-centimetre tube, came out from the very first observation thus made 0029 centimetre per second. Kohlrausch’s theoretical number, deduced from conductivity and migration data, is 003. Later experiments gave respectively ‘0026 and 0024. SO, seems to travel at about one-third this speed. — Another experiment was made with NaHO in the cathode vessel, and CuSO, in the anode, and with NaCl and phenol-phthallein in the tube, as before, but colourless (p.409). HO now travels against the current and pro- duces colour as it goes. It seems to travel nearly as quickly as hydrogen. The following abbreviated excerpts from Laboratory Note-books will sufficiently alustrate the results so far attained. Specific Gravity Data.—11°‘73 grammes of crystallised baric chloride added to 88:27 grammes of water give a solution of sp. gr. 1095, containing about 10 per cent. of the salt itself. One-thirtieth of its bulk of water added reduces it to 1-093. 22°68 grammes of crystallised sodic sulphate added to 77-32 erammes of water give a solution of specific gravity 1-093, likewise containing about 10 per cent. of the salt itself. 19°98 grammes of hydrochloric acid added to 80:02 of water make sp. gr. 1098, and is a 25 per cent. solution. This also was reduced to 1:093. Experiment made of inverting a test-tube containing one of these liquors into a pneumatic trough containing another. In each case pretty rapid mixture resulted. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 397 The hydrochloric acid solution was then diluted with an equal volume of water, making its sp. gr. 1030. A test-tube was filled with this and inverted over the baric chloride solution. There was no visible mixture; the place where the two liquids met remained quite sharp. October 30, 1885.—A tube of uniform cross section and °41 centimetre internal diameter was taken and bent as shown in fig. 3. Its total length was 84:2 centi- metres. This tube was marked No. I. It was filled with hydrochloric acid solution, of specific gravity 1-030, slightly tinged with litmus. Two vessels containing the 1:093 solution of Na,SO, and BaCl, respectively were arranged with vertical sticks of electric-light carbon as electrodes, and their levels as carefully adjusted as possible. The final adjustment was performed by a _ short siphon tube with a pinch-cock in the middle, and full of hydrochloric acid of sp. gr. 1:093 (see fig. 3). The experimental tube No, I. was then introduced very carefully at xiv. hrs. 58min. At xy. hrs. 2 min. the pinch-cock of the levelling tube was closed, and the current started, flowing from BaCl, vessel to Na,SO, vessel. Current strength ‘01 ampére. October 31.—Noon: ring beginning to form 22 centims, from Na,SO, end, and ° G2 mess » BaCl, end. November 2, 1885.—Another similar experiment with same tube. Levelling tube started at xi. hrs.49 min. Experimental tube put in xi. hrs, 55min. Levelling tube closed at xii. hrs. 2 min., and current started of strength ‘01 ampére. By November 3, at ix, hrs. 47 min., ring formed ; and at xiv. hrs, the current was stopped. Strength, ‘007 ampére. Solutions then tested and found all right ; apparently a satisfactory experiment. Distance of ring from Na,SO, end 24°6 ; » BaCl, .s 59°6. November 3.—Another experiment started with the same tube; fresh liquids still with density 1-093 for BaCl, and Na,SO,, the HCl (coloured with litmus) of density 1:030, Levelling tube put in at xiv. hrs. 30 min. ; experimental tube at xiv. hrs, 34min, Levelling tube closed and current started at xiv. 36 min. Strength of current, 009. On November 4 at x o’clock the ring was formed. Distance from Na,SO, end 31:8 centims. a el, s, eae November 4.—Similar experiment, except that the tube is filled with an un- coloured solution of HCl of ordinary testing strength, that is, one centigramme molecule in 5cc. Average current strength, ‘009. . Distance of ring from Na,SO, end 168 centims. ” ” BaCl, ” 67°6 ” November 6.—Another experiment with the 01 HClis 5cc. Current strength “009. Distance of ring from Na,SO, end 16°4 ; ” » BaCl, ,, 680. November 7.—A blank experiment arranged purposely with no current. Tube put in and levelling tube closed at xiii. hrs. 35 min. By November 16 there was no ring formed and no deposit anywhere in the tube. November 24.—Two other similar tubes prepared, each of the same internal diameter—41 centims.—but of lengths, No. II. 87 centims., No. III., 88-4 centims. The three tubes were then filled with the HCl solution (-01 in 5 cc.), and arranged with three pairs of vessels in multiple arc. The result was that, while the precipitate occurred in tube I. in about its usual position, in tubes IJ. and III. it occurred quite atend of the tube where it dipped into the Na,SO, vessel, and accordingly most of it fell out of the tube. 398 REPORT— 1886. December 1.—Another experiment started ; tubes I. and II. as before, but a layer of paraffin over the vessels of tube III., and a siphon levelling-tube full of paraffin dipping into it and left open, as shown in fig. 4, The current strength decreased steadily from ‘01 to ‘005. In tube II, the chief precipitate occurred again close to the Na,SO, end. In tube I. the distances were 16°5 centims. from Na,SO, end. 67°8 5 Ba,Cl end. In tube III. they were 20:2 is Na,SO, end. 68'3 i Ba,Cl end. Precipitates appeared on Dee. 3. December 3.—Paraffin levelling-tubes now provided for both tubes II. and III. ‘The ring formed well in all three now, and quite blocked the tube. ‘The distances ‘were— 15 centims. from Na,SO, end. In tube I. 69 : BaCl,. 4 {21 Na,SO, end. So es, A cud. . 21°5 Na,SO, end. Hs tube III. 66-7 # BaCl,, 2 Current strength in each tube’ about ‘01 ampére. December 5.—Same experiment repeated with 22 cells, tube I. being the only one without paraffin. The distances were— I. i, 6 From Na,80,end 161 22:2 29-9 From Bal, end 676 «648 66" Current strength about ‘015. December 5.—The same experiment repeated, but with only 3 cells. By December 9 a ring had formed in II. and III., but not in I, Distances of ring— Tube 1 259 from Na,SO, end. * } 60:9 from BaCl, end. 27'1 from Na,SO, end. In tube TIL. } 66.9 from BaOl, end. Current strength in each tube about ‘002 ampére. Experiments with tubes of different bore. Two fresh tubes were prepared, Nos. IV. and V., of about the same length, but smaller in bore than the first Fie. 5. three, No. IV. being about ‘3 Ba Soi centim. diameter and No. V. = 29 , j Na, SO. about 22. : Lee DEH J ?""* (For more accurate gauging of \Ba Clz ll the tubes see below.) W a December 9.—Two tubes, Nos. “ . and V., arranged in series; eo two other tubes, Nos. Ill. and { ( Tube IZ Dect. \\ “250% TV, also arranged in series, and ——————— the current from 16 secondary Ballz cells allowed to divide between the two pairs, starting at 4 p.m. on December 9. Fae aa, Na S04, Current streneth in tubes III. Ba sox TubeY Dec 14 * and IV. decreasing from ‘0075 to \Ba Zz *0035; in tubes II. and V. from ‘005 to ‘0012. By December 11, 10 a.m., a ring was almost completely formed in tube IV., fairly so in V., an indication in III., and nothing in II. By December 12 a ring formed in tube III., and by December 14 it was beginning also in tube II. On December 14 the state of the tubes was as sketched in fic. 5. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 399 On the 15th the state of tube II. was this :— Fig. 6. BaSO4, ( a Tube IT Dec.is. \y Wag 50s ; Ballz A small arrow marks the place of first appearance of the ring in fig, 5, The distances are as follows :— II. Il, TY, Ve Distance from Na,SO, end 19:0 175 30°5 45°8 = BaCl, end 667 695 547 407 December 15, 7 p.m.—Vessels_ same as in last experiment, but tubes arranged II. and IV. in series, one pair, and III. and V. in series, the other pair. Current strength in II. and IV. from ‘0095 to ‘0044; and in III. and V. from “0062 to :0022. By December 16, 4 P.M., deposit showed itself in tube IV. December 17, 10 a. M., ring formed in tube IV., and almost complete in II. An indication in V. By 3 PM, the ring in V. was complete, and a slight deposit in tube III. On December 20 ring complete in III., and current stopped. Fig. 7. |Ba50, Na,SOz Ba Cz Basodz ———$—___—__—_> Tube ai X 35 Dec 17 Naz504 . ) Ba Cle Bal$0z TubeV atXV. 45 Dec.17 Distances of ring when first formed— in tube i. TIL. IV. Vv. from Na,SO, end Pailtsy 9 FAIL 286 24:3 » BaCl, end 645 698 564 622 Gauging of the tubes, January 6, 1886.—Determined bore of tube by filling them with mercury at 2° 0. I II Ill. IV Vv. Length in centims. . 825 85°7 87'3 85:4 86:3 Pepe mercury Alling 1570 | 1615 | 157-92 | 1194 56°65 ube, in grammes . Calculated volume . : 116 12:0 11:7 84 4:2 Sectioalarea. . . | ‘14 14 134} 0983 | 0487) Diameter of bore | 423 ‘428 ‘404 355 "25 400 REPORT—1886. January 7.—Experiment with all four tubes in multiple arc, two of them dip- ping into the same pair of vessels; the solutions of BaCl, and Na,SO, weaker than before, viz., sp. gr. 1-050, because in the cold weather the sulphate of soda was apt to crystallise out of the old solutions. Current started at 5 p.m., 20 cells. By January 9, 9 A.M., rings were formed in tubes IT., III.,and IV. No ring in V., but some air-bubbles had collected in it, and apparently stopped its current. The rings in Lf. and IV. were beautifully sharp. Il. bbe IV. Distance of ring from Na,SO, end 17:0 65 16:9 68:7 808 685 January 9.—Another similar experiment but with 16 cells. By the morning of January 11 rings were formed in 3 tubes, and one was forming in tube V. Il. iit. DV, Vv. Distance from Na,SO,end 26° 10-4 21:0 33°7 7 BaCl, end 59:2 76:9 64-4 52°6 January 22.—A precisely similar experiment, except that 20 cells were applied. By January 23 (evening) rings were forming in three of the tubes, but there was an air-bubble again in V. II. TI, :¥ EN, Distance of ring from Na,SO, end 34:3 22:3 24-4 i y» BaCl, end 514 65:0 61:0 February 1.—Similar experiment. II. III. Ly V. Distance from Na,SO,end 382 30°6 26.2 23°1 A » BaCi, end 475 567 59:2 63°2 So far the data are not satisfactory. There is a decided consensus in favour of the more rapid travelling of Ba than of SO,, but no estimate of the ratio of the velocities can be relied on. The average makes Ba travel 3:2 times as fast as SO, (see p. 394). Experiments on jelly-jilled tubes. Four new tubes were made of dimensions and numbers here specified :— Number VI. VII. Vul. DX Length 866 88°53 84:8 103°8 centims. Diameter 327 “460 ‘476 "625% A gelatine solution was made by dissolving 20 grammes of gelatine in 150 cc. of dilute acetic acid of ordinary testing strength, viz., 1 centigramme molecule per 5 ce., the tubes filled and allowed to go solid. The tubes were arranged in multiple arc with a galyanometer able to be switched at pleasure into the circuit of each. The solutions in the vessels were BaCl, and Na,SO,, as before. February 13.—The E.M.F. of 24 cells was applied to these four new tubes at noon, and readings of the current (which was very weak) taken at intervals. It was found that something in travelling from the anode vessel (presumably the Ba) rendered the jelly turbid, and that the turbidity, being sharply defined, served as an indication of the distance to which this ion had reached. Marks were accordingly made on the tube to fix its position at different times, the distances of these marks from the end of the tube being afterwards measured. After a time the SO,, travelling from the other end, met the Ba and precipitated a sharp ring of BaSO,, whose position was noted. The current was not stopped, however; it was left on to see at what rate the precipitation advanced, and whether it advanced in both directions or in only one. In the free liquid HCl tubes it had seemed only to advance in the direction opposed to the current, viz., towards the BaCl, vessel. It was now observed in these jelly tubes to widen out both ways, but faster towards the BaCl, vessel than towards the Na,SO,. It was specially noticeable that in these jelly tubes the disc of BaSO,, indicating the meeting of the ions, formed near the middle of the tube, instead of much nearer the Na,SO, end, as it had done in free liquid. Thus while Ba travelled 41'1cm. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 401 to the meeting-place, SO, travelled 45:5, in tube No. VI. In tube No. IX. Ba travels 47-8, while SO, travels 56°6, and so on ; see following table. SUMMARY OF EXPERIMENTS ON TRAVELLING OF BA THROUGH 4 JELLY TUBES. Date Tube VI. Tube VII. Tube VIII. Tube IX. saijece | 2é.\ 2 | ga) | 8 | Ba) ok + Peps) aa = 2. ae P| a SS Se = 2. Day. | Hr. min. ge 22 ge Ea a Ee ie ze $3 | 8s | 22 | o8| 88 | 68 | #8 | 68 AS €/] as e/a A | AS A Feb.13| x1r 0 |started| -12 |started| -18 {started ‘22 | started “54 mle) XIV 10 = 12 — “21 — 25 = 56 SLB! | > KIT |B 6-9 12 65 "24 el 28 59 “76 er Lb) VEG 788 | 14 741 | °32 81 39 67 83 ay Le 2.0.9 Fs 8:75 | °12 8:25 | “21 8°95 25 73 “61 & LG x 10] 11:12] -12 10°12 | :21 11°33 "25 8:92 ‘61 ay AGH axe BON h a Vor | S14: 12°95 | °24 12°95 28 10:2 64 ae xr 10} 15°45 | -11 14:55 | -21 15°65 23 1271 “46 » 18 x 10| 19°15} -16 18:02 | °-26 19°32 30 14°8 75 » 18/xvir 10} 21:08 | -17 19°9 26 21°25 “33 16°12 “82 oo x 10 | 23°98 | :10 22°7 chi 24:2 “21 18°3 “49 ». 19] xxr 28 | 25°6 ‘09 24:25 | -16 25°93 akg 195 — » 20 x 10| 27-2 “09 25°85 | 16 27-6 *20 20°8 _— » 20) xx 16 = 16 27°45 | -20 29°32 23 22:0 —_— » 21 Ix 45 | 30°55 | 11 29°2 18 31:2 “20 23°43 — » 22 xX 15 | 33°68 | -12 32°55 | :18 34:5 “24 25°8 —_ » 23 x 10} 37°05 | -10 35°72 | +16 38°15 18 28°45 — » , 24 x 10 | 39°72] -09 38°5 16 40°6 18 30°5 — » 25 x LONI ‘ll 40°85 | *16 41°22 18 32°6 = Ba SO, disc Ba SO, disc forming formed Ba SO, disc forming s ob)| &xXE 15 = 09 41:3 14 — 16 33°7 —_ » 26 Bde CU) | pe ‘09 = 15 41-5 1 34:8 — ia Cid gbeee 1 ial = ‘08 — oO — 18 375 —_— current stopped 429921). f ae se Sede cmttlbin shel ahve l 13 don Te eee 'March4| x - 10 anes sabbady Gaara becca boa Lift SEU n yaies current stopped - 43°] : Btn gl iessertay) Selita wsrop w 277 y jos ab fore f 17 | 4782| — BaSO, disc just forming. < x 10 _— — — —- — ‘13. 'Disc2mms, wide current stopped. Experiments on travel of both Ba and Cl through jelly tubes. _ Four fresh tubes, numbered XII.—XV., each 40 centims. long, and more simply bent, were filled with the following jelly, containing sulphate of silver as a test for the presence both of Ba and of Cl. The jelly was made by taking 40 cc. of the previous acetic acid gelatine and adding to it 10 ce. of the following solution, viz., 20 ce. of nitrate of silver sol. (AgNO, in 50 cc.) +2 ec. sulphuric acid (H,SO, in 1 The 3 pairs of bracketed numbers about this date relate to the two ends of the plug of precipitated BaSO,, and show the rate at which this plug grew in thickness. 1886. DD 402 : REPORT—1886. 10 ce.) +78 cc. of water. Tube XIV. was ‘562 centims. in diameter; the others were not measured. The tubes were arranged thus :— Fie, 8. so that the current through any one of them could be measured, with short interrup- tion to the others. The anode vessels contained BaCl,, the cathode vessels NaCl. The E.M.F. of the applied battery was measured by an Ayrton and Perry volt- meter as 29 volts. TABLE OF RESULTS. Tube XII. Tube XIII, Tube XIV. Tube XV. Date I » ~ Poe ~» Distance FI q Distance a = Distanee ad Distance 8 5 travelled by |#.8] travelled by |5.=| travelled by |.S| travelledby |S Day Hour Ba Cl S| Ba Ol eo] Ba Cl BH] Ba jPCl iss O8 Og A es Feb. 22 |xvu130 started 52 0 0 |°36 0 0 | -68 0 0 | -50 » 23 x10 41 8:3 | °41 39 78 | 29 4:4 38 54 3°93 80 “41 » 23] Xxi110 6°85 13°9 | *41 6°63 13°3 | °29 65 14°5 56 70 13°82 | °41 3 ot x10 9°4 18°8 | *41 90 180 | °2 9°0 196 | °53 96 18°9 41 » 24] XxI45 121 241 | 44 115 23'1 | °32 116 25°0 | °57}| 122 24°42 | -44 » 24| xx1r50| current stopped | 0 _— — 0 — — 0 7 _ 0 Three faint extra precipitations were observed later, besides those caused by the recent current. They are here referred to as a, b, c. (a) 48 0 | (a) | os = = | = fs Feb. 27 — | (0)12-26 |(c)2568| ~ | v4 Sees A XII (a) 4:75 * (b)12°85 = 0 (c) 26°5 | 0 Late on February 24 the curreuu was stopped because the advancing ions had nearly met, and it was desired to observe whatever phenomenon might accompany their meeting. The tubes were left in position for a day or two, and by February 27 it was found that, while the precipitation boundaries due to the current still remained, three other fainter outlines had made their appearance, one, a fresh one, crawling along from the BaCl, end, the other two advancing beyond the current- formed precipitate. The three are labelled in the table a, }, c respectively, and their positions are indicated ; but no meaning is yet attached to them. The result of these experiments is to give a rough absolute determination of the rates of travel of Ba and of Cl through the jelly, and to show that the speed of Cl is pretty exactly twice that of Ba. Now can this be assumed to be probably due to the fact that barium is a dyad, while chlorine is a monad? or is it due to the fact that the atomic weight of Ba, 137, is almost twice that of Cl,, viz.,71? The simplest mode of examining this question is to replace the chlorine by bromine or iodine, whose atomic weight is quite different, while its valency is the same. Similar experiments with iodine instead of chlorine. The cathode vessels were filled with a solution of potassic iodide instead of with sodic chloride solution. An E.M.F. of 29 volts was again applied to the same four tubes, filled with the same jelly as before, and the results are subjoined. The precipitation on the advancing iodine side was, however, double; one faint outline in advance, which it was suspected might be due to a trace of chlorine impurity in the KI, and the main precipitation, which was considered to be real Agl. Successive positions of the faint advance cloudiness are recorded in the following table in parentheses below the numbers giving the corresponding main advance :— 403 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. poT[PAvay oouezsicy “AX 940.1 ‘pesuvire yuomitedxe 1eyjoue pue paddoys yuermo Bq (ZL) 09- F9-86 h (1-T8)_ g¢. g.61 (4.1) Zo. 9-21 (¢-8) SF. PL CF. 18:2 99. 0 16: _ (9-83) 9. 6-06 (¢9-F1) ep GL-T (9-01) ¢9. £6-6 (46-8) 29: 8 gg. 6% cg. 0 5 : 5 5 poypeavay eae “AIX °qUL OF -AT[ByUEptooe uexorg “TIIX equy (80-12) 19-61 (Z-F1) (1e'e1) (¥-01) (91-6 (ZL-8) ZL-8 00-€ 0 I 4q te q peTfeavay souvystq “TITX °(.L (9.06) 62-61 (Z0-F1) 91-1 (¢-0T) 96 (¢.8) 80-8 oL-F 0 I 4q aq PeT[oAvry 2oUB4STG, “TTX P40, 9¢ ITAX | OT QT x OL eG IIIAX} 6 CF XI 6 Tg IxX¥ |8 oF AX 8 06 X 8 QT IIx }L 9¢ Xx. 19 g& IIIx | 9 OT X 9 €P? Ixx | 9 GZ IAX |g MOF, ou8q « oe “ “IBN he I €-66 2 0:62 |R F1-62 F1-62 F1-66 9:86 404 REPORT—1886. Semilar experiments with bromine. The cathode vessel was filled with a solution of potassic bromide containing 30 grammes of salt to 300 grammes of water. Tubes filled with same Ay,SO, gelatine as before, each 40 centimetres long. Tube XII. Tube XIII. Tube XIV. Date E.M.F. Distance = a Distance a= & Distance = = travelled by z a travelled by 2 3 travelled by BE Day Hour Volts Ba Br 5 g Ba Br 5 q Ba Br 5 =I I March 30] xv 50 26'8 0 0 +39 0 0 57 0 0 39 3 «On 1x 50 27:0 |46 9°2 85 | 4:4 96 52 | 46 9°0 *34 (9°7) (10:05) ( 9°4) » 31] xvr155 286 | 7-15 13°6 44 | 66 1421 63 | 71 13:4) “42 (14:37) (150 ) (14*1) April 1 x17 27:0 | 121 23°0 *39 |11'8 23°8 *56 |11°9 22°6) *38 (23°9) (24°72) (23°6) As in the iodine experiments there was an advance cloudiness, faint but well defined, in advance of the main precipitate. The readings of the position of this are specified in the above table in parentheses. The meaning of it was not cer- tainly made out, but it was provisionally set down as due to impurity. Combined experiments on several substances. It thus appears that Cl, Br, and I all go at about the same rate and about twice as quick as Ba. It remained to see what strontium and calcium do. Calcium is not an easy substance to experiment on; its sulphate is too soluble. But strontium is sufficiently easy, though not so sharp and well-defined as barium. To make a better comparison six tubes were taken, each 40 centimetres long, filled with the same Ag,SO, gelatine solution as before, and arranged in multiple arc with the same E.M.F. (about 40 volts) applied to all of them. This is the E.M.F. between the electrodes, and since gas is given off at the carbon electrodes some- thing like three volts must be deducted for polarisation and for resistance of liquid in vessel. But it was not thought probable that absolute results could be of much use when the composition of jelly is so vaguely known. The diameter of tube XIX. was ‘370 centim. Fig. 9. The six tubes were arranged as in figure 9; the two anode vessels being filled, one with BaCl,, the other with SrCl,, and the three anode vessels with NaCl, KBr, and KI, respectively; in each case 10 grammes of salt and 100 ce. of water, 405 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. Pd GHL| 98: (98.28) ( g.9T) BST 81-6 G9 8 ft) 0 (¢-86) 9:88 OFT (9.91) 0-9T 0-01 Lg Le i) 0 86:26 0-91 90-91 £01 9-9 £-€ 0 0 rj = 9.88 rn — £07 a. = 8.07 a a 9-07 ['soqwqidoord oouva pe 4trey oY] JO WoryIsod oy 07 toyor UTUse sosoyyuored Ut stoquinu oyy) *paqreys UOUITIedxe Lot JOUR LP TIAX Stx 09 IXX eT AX gt eunr PUB *[O8 9UT}B[Ad Iq} JO *09 OF 09 “(OT ATMO Jo peogsut) ‘TOs "OS°SV oY} JO ‘00 cy “zlA “Tos *OG’SY AasUOAys ITA pPoy[yor ot9M soqny oo1t7 os ‘paxreut Aptespo AeA YOU SBA AS OTT, » 9 — ae ( 0:02) FL. G81 6-01 6:9 ) TL: 0-9 62 GL. 0 0 Bo | =F] I ag Eg Aq paT[eavay Et aowe4ystq ‘IXX 9401 a * (8.61) 9-81 §-11 (9.9 ) ¥-9 €-€ 0 0 Ba ae Ig qwW S| fq popjoavay 3 5B aoueysi “XX equy, 10 wg Aq peaT[aaery ooueysiq “XIX 940, ‘ag ‘T ‘10 ‘ag ‘vg NO LNEWIUdadXY AAILVAVAWON I eg _ Aq porteavr, aoueqsiqg ‘IMAX 990 $3 9-E1 (F-61) 9-81 £6 (¥.9 ) L9 £8 0 0 Ig eq Aq payjaavty aoueysiq “ITAX 9qnL £02 L6 8-18 1:9 0-€ -88 0 0 6-8 10 Bg HOA Aq pay[aavay a0uvysiq TW ‘TAX 990 og ITIAX st x 88 XIX OF TIX ImoH . IT aune Avg oye 406 REPORT—1886. Determination of the resistance of a jelly-filled tube. July 1.—One of the 40 centimetre tubes filled with plain gelatine gave 67,720 ohms resistance. The same tube had the jelly melted out, the tube cleared and filled with dilute acetic acid (centigramme molecule in 5cc.), and its resistance was now 160,000. : Another determination, by Mance’s method, gave for the acetic acid filled tube 142,000 ohms, at 21°C.; for the jelly-filled tube at 19:5, 78,000 ohms; and for the same tube filled with dilute sulphuric acid (H,SO, in 10 cc.) 730 ohms. This jelly tube was then left to stand all night with its feet in dilute acetic acid. By the morning its resistance had increased, as the acid soaked up into it, to 84,000 ohms, Improved experiments on the velocity of tons in free liquid. Any siphon tube arrangement joining two open vessels cannot be free from difficulties caused by electric endosmose, whatever precautions be adopted. Hence a series of experiments were plan- Fie. 10. ned with one of the vessels closed and completely full, so that no more or less could be driven into or out of it, either by the action of the current or by changes of level, except such calculable changes as result from alteration of volume of electrode or solution near it, or from changes of temperature. To this end the cathode vessel was made of the shape shown in figure 10, and the experimental tube fitted to it by a ground joint. It was necessary to avoid evolution of gas, so the cathode vessel was filled with saturated sulphate of copper solution, and it was immersed in a constant-temperature water-bath. The tube was 40°7 centimetres long, and was filled with dilute HC] (1 centigrarhme molecule in 5 ec.). The anode vessel contained a solution of baric chloride (10 grammes salt to 100 of water) and a carbon electrode. The internal diameter of the tube was ‘393 centim. August 7.—The cathode vessel having been in the bath all night, and the tem- perature being 16-2°, the tube was put in at x. hrs, 20 min. , and the current started at x. hrs. 48 min. with a difference of potential of 51-3 volts between the electrodes. A silver voltameter was included in the circuit, By xxii. o’clock there was no ring formed in the tube, but in the bend near the cathode end of the tube there was a slight deposit. The temperature of the bath was still 16:2°. It was afterwards found that the silver plate of the voltameter had dissolved, and thereby broken contact. August 9.—Another precisely similar experiment ; except that a galvanometer: was used instead of a voltameter. Current started at xii. hrs. 15 min. with E.M.F. 50°6 volts. The galvano- gi isle meter readings fell” oradu- ally from 6:7° to 3°8°. At ts Wat Size Ground Joint fF xvi. hrs. 40 min. a dise of sla precipitate was found in the Vt tube, the volts being now : ire : 49-7. The thickness of the disc was *17, and the positions of its two faces were 3°79 and 3-96 centims, from the cathode end of the tube. Result sketched here, fig. 11. Summary of the experiment. Time taken for ring to first form, estimated at 4 hours. Distance travelled by Ba, 36-9 centims. =6 +2, i SO,, 3°96 centims. = a—.. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 407 Average difference of potential between electrodes, 50°15 volts. Length of tube, 40'7 cm. Diameter, 0'395 cm. Current from 5 to 2-7 milliampéres. ‘ The z in the above relates to a possible contraction of the contents of cathode vessel, to be determined later. August 10.—Another simi- Fig. 12. lar experiment with same a tube. Result sketched in lee fie. 12. SY os Time taken for ring to form, SR 2 | Ft 8 hours. Distance travelled by Ba 37-3. Distance travelled by SO, 3:55. Difference of potential, 48-4, Current from 4 to 1°5 milliampéres. Blank experiment with no current on, to see the effect of diffusion. August 12.—Tube connected at x.30. No ring formed, but by August 17,xiv.30, a slight precipitate was forming in the centre of the tube, #.e., after 5 days 4 hours. Experiment on the travelling of hydrogen. August 17.—The same apparatus as in fig. 10 was again used, but the solutions arranged as follows :—In cathode vessel, sat. solution of CuSO, as before ; in anode Te, 13. (S04) (current) <—— i) HORIZONTAL LENGTHS ARE DRAWN TO SCALE VIZ-z REAL SIZE vessel, dilute sulphuric acid; in tube, the following: 49 cc. of sodic chloride sol. 408 REPORT— 1886. (5 grammes salt in 100 of water) with 1 cc. of baric chloride sol. (BaCl,, 2A¢ in liche elled Cre LILO Fie. 1 shay Atig. 17 15 centim. 7T'ime wu minutes 4, SS 3 ae = S S$ a Current Plotting of these numbers. centigrammes, or 2°44 of the crys- tallised salt, in 100 cc. water); add to this a little phenol-phthal- lein, and just enough NaHO to make it red. The destroying of the colour is the thing observed. No measurements made till the liquid is discoloured round the bends of the tube. At xvii. 43 the current was started, with an H.M.F. of 45 volts between ter- minals. The galvanometer deflec- tion increased from 41:1° to 442° in the first half-hour, and then increased further to 46° in the next hour. By xvii. 51 the de- colorisation had got round the bends, and the first or starting mark was made. The progress of the whole experiment was rapid, and is represented pictorially in figs. 13 and 14. In the following summary the column headed, ‘ Progress of SO,’ gives the position of the marks made near cathode end of the tube. The column headed ‘ Pro- gress of H’ gives the position of the marks made near anode end. By these headings it is not in- tended to insist that the full theoretical meaning of the obser- vations is the same as the ob- vious and apparent meaning. All distances are specified in centi- metres. 2 Current in Progress of Time milliamperes SO, Progress of Hi XVII 51 7'8 0 0 Aes, 216) — 05 1°45 XVIIL 6 — 115 3°65 » 16 —_ 1°65 5°33 = 786 8:7 2:2 | 69 OG 88 2°6 8:5 » 46 9-0 3:15 10°05 » 56 91 38 11°6 XIX 6 9:2 4:4 13°21 ws LG 9°3 4:9 | 14:79 Current | stopped. 626 0 4-98 15:13 3. oO 0 4:98 | 15°35 » 46 0 4-98 15°51 xXx 66 0) 4:98 15°59 4 6 | 0) 4-98 15°61 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 409 August 18.-—Another similar experiment, but with a little more NaHO added to liquid in tube to make colour more distinct. No good observation could be ob- tained of the SO, progress this time, as it did not get up to the bend, but the H progress was read. The tube was graduated in millimetres for this experiment. 45 volts applied. Time et eoteeae hom ac 4 a mney paear Galvanometer readings Centimetres xv 0 = 40°5 3, 55 28:2 41°3 Xvi 5 26°35 42:3 an Lb 24:93 42°8 OD 22:07 43°5 +, 0D ily 44-0 Xvit 15 16°32 44-7 » 40 12°71 459 » 50 Current stopped XVIII 0 10°9 and 10:1 0 aslo 108 , 98 0 » 20 106 , 93 0 Current started in reverse direction a oe 103 , 88 = y AS 35) 5.. (78 — 3 O83 about 9°5and 7°8 —_— Boundary getting indistinct The double number in the middle column represents the two ends of a slope into which the boundary threw itself as soon as the current was stopped : indicating convection. A galvanometer deflection of 45° means a current of ‘009 ampére. In the last experiment the tube was not perfectly horizontal, and this may have caused some disturbance. In future experiments the tube was carefully levelled to begin with. Experiment on velocity of copper. August 24.—Started an experiment with CuSO, in both vessels, and in tube some NaCl with a little K,FeCy,. But the indicator did not form a sharp boundary across the tube, and the experiment was not very satisfactory. 65 volts applied. Current in milliampéres At x1 15 Current started 10:0 we XLV OG, F- ; : Reading on tube was 29°3 —_— oy le Gid e Come : F , a os 21°8 — APXVID OF ore , : : 5 = 18°7 8-9 99 XVIIL37 . : C : cD + 173 8:7 Experiment on the velocity of hydroxyl. August 25.—Made an experiment on the rate of travel of the hydroxyl radicle of NaHO, by using the closed CuSO, vessel with copper electrode as anode vessel, and putting a solution of soda in the open (now) cathode vessel, fig. 10. The tube contained NaCl (5 grammes in 100 ce.) with a little phenol-phthallein not coloured as yet with alkali. The appearance of colour was the thing to be observed as the HO travelled against the current and attacked the NaCl. 65 volts applied to electrodes. Tube 40:7 cm. long. For diagram of results see fig. 16. * It would seem probable that there was some unknown misreading here ; probably 7 for 9. 410 REPORT— 1886. { i Progress of HO).) Current in 2 Progressof HO).| Current in ve ae on tale milliamperes tine ates on ay milliamperes x 50 Tube inserted. 10) XIII 39 12°4 11-2 mE Ly Current started 9-4 = OD 9°58 11°4 ey EY 29-0 10°3 Rove 9°30 Current stopped esate 9 27:0 — ag 88 0 | are |) 25°18 | 10°4 et oe 8-49 0 yy ae 21-7 10°6 ok 8:26 0 ay) 18°3 10'8 AL 8:0 0 | xiir 19 151 11:0 3. UD 172 0 Another experiment on the velocity of hydrogen. August 25.—Closed vessel (fig. 10), containing CuSO, used as cathode vessel again open vessel, containing dilute H,SO,. Tube containing NaCl (5 to 100) with a little phenol-phthallein and a touch of NaHO as before. . Reading on Current in : Reading on Current in cams abe milliampeéres Tame tube | milliamperes XV 47 Current started 9:4 XVII 36 10°80 12:0 » 56 29°19 — >» 56 6°83 12:3 XVI 6 27-00 10°4 relies 6:43 Current stopped » 16 25°15 10-6 XVIII 10 6:00 0 7. BO 21°65 1r0 Eee) 5°85 0 soe 18:06 et ei!) 5°65 to 5:3 0 Xvi 16 14:50 11-4 This experiment seemed to go well. The numbers are plotted in fig. 16. Successive appearances of the tube are shown in fig. 15. Fie. 15. xx: aT es ess pe LE se Current Stopped xvuss Som a ns Experiment on the velocity of ammonium. August 26.—Made several attempts to get the speed of NH,, using Nessler solu- tion. The indicator is not very distinct: no precipitates seem to work well as indicators ; they introduce disturbances. Fluid detectors answer better. Ammonic sulphate was put in anode open vessel. The tube contained NaCl + Nessler solution. 65 volts applied. ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 411 Time Reading on tube Current XIII 29 — Current started Pepecis 28°05 10:2 » 46 26°10 — | 93 06 24:25 10-4 XIV 6 22-70 as » 16 21°30 105 | » 26 20°20 10°4 Current stopped | Sy GENE 2071 0 Current stopped because boundary was getting indistinct. This did not seema very good experiment, but it is better than some here unrecorded which preceded it. August 26.—A similar experiment with a drop of phenol-phthallein added to liquid in tube, because its indication is sharper. and therefore unsatisfactory to read. PLOTTINGS IN FIG. Boundary, however, still sloping, Current stopped Time Reading on tube Current XIv 48 Current started 10-1 ” 54 27°55 2s xv 4 24-4 —_ 5b ot: 22°3 10°6 »» 24 20°55 ds » o4 19-1 10°6 Fra, 16, Further experiments on the meeting of Ba and SO, ix gelly tubes. It may be remembered ; that, whereas in free liquid Re ry oe ser? OD Ba appeared to travel about three times as fast as SO,, the precipitated plug of BaSO, nearly always ap- pearing much nearer the Na,SO, or cathode end of the tube than near the BaCl, end, yet in jelly tubes they appeared to travel at about the same rate, the plug of precipitate forming near the middle of the tube. To make sure that there was no error of observation here, and to see if constitution of jelly affected the matter, a few experiments with jelly tubes were repeated, and different strengths of jelly Plotting of the last four tables. gs pie 24.—T wo tubes, each 40 centimetres long, were filled with jelly made by dissolving 40 grammes T ! ----------------------- | t ! 1 ! | ' ' ! current stopped 412 REPORT—1886. of gelatine in 150 ce. of dilute acetic acid, of strength one centigramme molecule in 6 cc. Another pair of similar tubes were filled with jelly made with 40 grammes of gelatine dissolved in 150 cc. of four times weaker acetic acid, viz., a centigramme molecule in 20 ce. 58 volts were applied to the carbon electrodes of all four tubes. The anode and cathode vessels contained BaCl, and CuSO, respectively. In the tubes with weak acid, BaSO, began to form in 284 hours after starting the current, and its position was 19°3 in one tube, and 19:2 in the other, from the BaCl, end, and therefore 197 and 19°8 from the Na,SO, end. In the tubes with stronger acid the precipitate took some hours longer to form, and its position was 19-2 in one tube, and 18°3 in the other, from the barium end. The relative speed of travel of Ba in the two pairs of tubes was taken by making simultaneous marks on each tube as the Ba proceeded ; and the ratio of these rates was in the weak acid tube 1-21 times that in the stronger acid tube. Thus, although the absolute speed is less in the stronger acetic acid jelly (as is quite right, because its conductivity is less ; see above), the ratio of the speeds of Ba and SO, remains practically unity in both. August 27.—To confirm, the four tubes were started again in just the same way, except that, while one pair contained jelly with C,H,O, centigramme mole- cules in 5 cc. as before, the other pair contained jelly with C,H,0, centigramme molecules in 40 cc. The distance travelled by Ba in the weak acid jelly tubes was 15°3 cm., and in the strong acid jelly tubes was 12-4 in the same time; giving a ratio 1-20 as before. So far as it is wise to draw a moral from unfinished experiments it may be said, that while there are some divergencies, yet they are in the main confirmatory of the theory of Professor F. Kohlrausch, especially in the case of the velocity of hydrogen; and I think it may be regarded as a noteworthy instance of scientific prediction if numbers calculated theoretically from conductivity data be found to agree at all closely with the results of direct experiment. 5 In conclusion, I wish to record my best thanks to my assistant, Mr. Edward Robinson, for the care and assiduity he has bestowed upon these experiments. As I have had occasion to remark in the course of the paper, he has not only carried out my proposals with ingenuity and skill, but he has in several cases modified details and devised fresh combinations. CONTENTS. PAGE 1. Mr. THomAs GRay, On Silver and Copper Voltameters. Communicated by Sir William Thomson (reference only) ‘ : = c . 308 2. Professor ARMSTRONG, On Electrolytic Conduction and Residual Affinity (reference only), : is : 4 : : : : - - 308 3. Professor McLEOD, On Ozone formed in Electrolysis (reference only). - 308 4, Professor J. J. Tomson, On Ohm's Law in bad Conductors (mote) . - 308 5. Dr. JoHN Hopxinson, On Continuity of Electric Conduction (letter and abstract) . : . - ‘ 2 5 2 = - - . 309 6. Mr. SHELFORD BIDWELL, On Diathermancy and Electrolytic Conductivity . 309 7. Dr. ARRHENIUS, Letters on Electrolysis. Communicated by the Editor . 310 8. Professor FitZzGERALD and Mr. TROUTON, On Ohm’s Law in Electrolytes . 312 9. Professor S. P. THOMPSON, On the Electric Resistance of Magnetite . . 314 10. Dr. ARRHENIUS, On Conductivity of Acid Mixtures. : é = - 315 li. Mr. W. N. SHAw, On Verification of Faraday’s Law for Silver and Copper . 318 12. Mr. T. C. FrtzpaTrick, On the application of Alternate Currents to Con- ductivity Determination. Communicated by Mr. W. N. Shaw 4 - 328 13. Professor F. KOHLRAUSCH, On the Conductivity of Electrolytes (abstract by Mr. Love) - ° . Br 7 . : - . 334 14. Dr. Lop@x, Appendix to the same : : : : : : 4 - 337 15. M. E. Boury, Criticism on Professor Kohlrausch’s Memoir . ; . 3839 16. Professor F. KOHLRAUSCH, Letter on the above criticism, e¢ ceteris . . 341 17. Dr. ARRHENIUS, On Viscosity and Conduction : Conductivity of Jelly - 344 ON ELECTROLYSIS IN ITS PHYSICAL AND CHEMICAL BEARINGS. 413 18. M. Boury, On Polarisation and Conductivity (abstract by the Editor) . - 348 19. M. Bouty, On the Conductivity of very dilute Salt Solutions (abstract by the Editor) ‘ 350 20. MM. Bouty and FOUSSEREAU, ‘On the use of Alternating Currents in Measuring Conductivity . 356 21. M. Bouty, On Mechanical and Thermal Effects accompanying Electrolysis (abstract by the Editor) . 357 22. Dr. ARRHENIUS (first part), On the Conductivity of Electrolytes (analysis by the Editor) . 357 23. Dr. ARRHENIUS (second part), A Chemical Theory of Hlectrolytes (abstract and translation by the Editor) . ; 362 24. Dr. ARRHENIUS, Letter respecting the above criticism. Communicated by the Editor, with afoot-note . 384 25. Dr. ARRHENIUS, Letter on the Relations between Conductivity and Vis- cosity. Communicated by the Editor. 387 26. Professor WILLARD GiBBs, Letter on Electro- chemical Thermo- -dynamies. Communicated by the Editor, with a note ; 388 27. Dr. OLIVER LODGE, On the Migration of Ions and an ‘Absolute Measure of Tonic Velocity . : : ; , . : : : : . 389 Siath Report of the Committee, consisting of Mr. R. Erurrinas, Mr. Txomas Gray, and Professor Jonn Mite (Secretary), appointed for the purpose of imvestigating the Voleanic Phenomena of Japan. (Drawn up by the Secretary.) [PLATE VIII.] I. The Gray-Milne Seismograph. In 1883, partially at the expense of the British Association, Mr. James White, of Glasgow, constructed a seismograph to be used in Japan. I am pleased to say that for some time past this instrument has been in good working order, and examples of the records which it has furnished are given in the following table. The time records are expressed as Tokio mean time. The particular wave at which time was noted can only be seen by reference to the original diagrams. It is usually very near the commencement of a disturbance. The period which is expressed in seconds is the time taken to describe one of the principal vibrations (or shocks) in a disturbance. The longest period, it will be observed, is three seconds. The amplitude, which is expressed in millimeters, is half a semi-oscillation, the vibration which is measured being the one from which the period was recorded. It will be observed that the larger the amplitude the longer is the period. I am writing more fully on the relationship of amplitude to period in a special paper. With period and amplitude before us, on the assump- tion of simple harmonic motion we may easily calculate the maximum velocity of motion which represents the projecting power of an earth- quake, and the maximum acceleration which measures the overturning and shattering power of an earthquake. The direction which is given is that of the most prominent vibration in the disturbance. One disturbance, it will be noticed, had a duration of ten minutes. Without the aid of an instrument this disturbance might have been felt for a period of perhaps three minutes. It will be noticed that vertical motion has only been recorded twice. The records given in the following table are in the same form as the records published in the Japanese daily papers imme- diately after the occurrence of an earthquake. The original publications followed Palmiere’s method, where a set of arbitrary degrees took the place of the present absolute measures. 414 Catalogue of Earthquahes felt at the Meteorological Department in Tokio, between 7 REPORT—1886. May 1885 and May 1886, as recorded by the Gray-Milne Seismograph. No. Bil Ampli-| Months | Day Time ‘5 3 | tude Principal Direction | Duration Age a iwi. H.M. § M. 8. V. 1 2 47 27 AM — — = = i. 7 8 58 8 aM -— — 2 49 i 19 | about 2 50™ A.M — — — a VI. 7 11 34 18 P.M — _— — = - 11 9 19 40 A.M 2:2'| 1:6 W. 11° N. 6 38 A; 15 1 41 41am 23 | 59 E.9°S 6 0 Pe és § 40 OPM — — — = - 18 1 36 45 P.M 18 | O08 W. 10°N 2 30 ra 28 2 24 18 AM — — = VIII. | 26 5 2 30 AM — — = = + 28 9 37 28 A.M —- = E. or W. 32 ee Mea Geena.) | — | — N.orS 10 IX. 2 8 31 42 aM O-4 | O-4 IN Tag) 25 38 10 819 6P.M — -= = i 11 1 24 30 A.M — == — 10 IX. | 20 113 50AaM 0-4 | O-4 | W.S.W. or E.N.E 24 - 22 2 29 43 A.M 16} 08 E. 27°S 1 20 om 26 0 2 45 P.M 3:0 | 13°7 UN Geen He 9 0 55 28 5 27 43 AM 2°2)| 11-1 Haplvciss 4 0 a 29 8 39 9AM — N. or 8. -~ X. 1 ideas) sayr(eiyai it 05 | 08 8. 42° E. 1 14 + 7 7 34 45 AM -- — E. or W. 41 ) 9 7 53 5 P.M. —- — KE. or W. 1 12 rf 11 | about 5" 30™ A.M. -= — N.orS 1 30 x 15 9 2 29 AM. — — N. or 8 doy ces = 5 8 43 18 P.M. eM ae Ore E. 29° S 110 a 21 1 19 35 A.M. 0-9 | O02 E. 29° 8 1 20 ut 5 12 58 A.M. 0-9 | O02 E. 28° N 1 39 5 “K 10 41 11 P.M. 2:9 | 1:9 N. 45° W, 4 48 . 30 8 31 16 P.M. 15 | 02 E. 17° 30'S 2 5 XI. 11 8 51 24 P.M. — — E. or W = : 16 1 50 36 P.M. O07 | O02 E. 27° §. 30 Fy) 20 7 41 35 P.M. -— — 8.E. or N.W. — XII. 3 6 1 42 AM. 05 | 02 5.W. or N.E. 50 ir 6 813 0PM. -- — E. or W. = ee 7 1 2 23 P.M. 0} 40 E. 12° 8. 5 0 is = 7 56 57 P.M. -- — E. or W. = 4 18 3 0 38 A.M. — — — a f 19 6 26 40 P.M. 10; 1:8 W. 29° N. 2 43 33 28 10 6 30 P.M. 18 | 3:3 N. 3 40 I. 5 4 23 42 PM, 08 | O-4 N. 26° E. , 23 ” 22 10 58 OAM. very|slight SNe 15 BS 31 7 22 46 A.M. very|slight S.-N. = II. 19 2 54 11 A.M. very|sligh E.-W. = 4 24 7 34 OAM. 06 | O05 N. 40° E 1 24 # 3 3 36 25 P.M. — 0-2 E.-W. 1 20 III. 2 5 13 49 A.M. 14] O-4 N. 25° 30’ W. 1 55 <3 13 6 25 OPM. 14 | 03 W. 33° N. 33 2 26 6 6 OAM. very|slight S.-N. 10 Ve eats 5 45 OAM. 14 | O7 8. 33° E. 3 10 x 23 4 22 22 aM, 1:8} 03 SN. 33 Vv. 3 noon _- 0-2 E.-W. 1 30 “3 8 10 14 OPM. 04) 28 W. 39° 30’ N. 1 40 vertical 03 | Ob | ON THE VOLGANIC PHENOMENA OF JAPAN. 415 ie Ampli- No. | Months | Day Time 5 © | tude | Principal Direction | Duration AY m.m. H. M. S. M.S. 660 Age 9 | about 35 10™ P.M. 22) 03 W. 37° 50’ N. 1 40 661 (5 11 2 31 58 P.M. very|slight S.E.N.W. 30 662 55 12 11 43 49 A.M. = 0:04 N.E.-S.W. 30 663 is 16 9 3 OAM. OF) a Ace E. 27° S. 3.0 vertical 04) O09 2 664 as 18 8 12 51 P.M. 17 | 0-4 E. 16° S. 2 25 665 as 30 8 38 18 P.M. very|slight — abt. 10 The successful working of the seismograph giving the above records has led the Meteorological Department of this country to have a number of somewhat similar, but less expensive, instruments constructed. These are gradually being distributed throughout the empire. One feature peculiar to the new instruments is that the drum on which the records are written instead of being in continuous motion is only set in motion at the time of an earthquake. When a drum or record-receiving surface is in continuous motion beneath the pointers of a seismograph, these latter, even with the best of instruments, will in time often describe a line the breadth of which may be greater than the range of the preliminary tremors of a disturbance. These tremors are therefore not visible on the record. We find by experience that a record-receiving surface which is only started at the time of a disturbance may be set in motion to receive the preliminary movements, and is therefore, in the opinion of observers in this country, better than an instrument where the record-receiving surface is in continuous motion. In conclusion to this portion of the subject, I may remark that observa- tions made with instruments at a distance of about half a mile from where the Gray-Milne seismograph is situated give for the same earthquakes amplitudes which are about twenty-five per cent. greater than those given in the preceding table. These instruments are on low flat ground, while the Gray-Milne seismograph is on ground which is relatively high and hard. Another point worthy of record is that very small earthquakes are sometimes felt upon the low ground which are altogether unnoticed by the instruments upon the high ground. IL. Frequency and General Character of recent Earthquakes. From the preceding list of earthquakes it will be seen that between the end of May 1885 and May 1886 fifty-six earthquakes were recorded at the Meteorological Observatory in Tokio. Many of these were very slight. During the previous year (May 1884—May 1885) seventy-three shocks were recorded. As I did not return from the Australian colonies until last November, I was unable to make observations on earthquakes which occurred during the previous autumn and summer. In consequence of this, I regret to state that the most important shocks of the season (Nos. 624 and 625) were not recorded by the instruments which are employed for special investigations. The special investigations now going on are observations in a pit and ona piece of ground which I have the intention of endeavour- ing to partially isolate from earthquake movement by trenching. If these experiments are ever completed they will remain to be described in a 416 REPORT— 1886. future report. In the report written last year some reference was made to the experiments in a pit. For a strong earthquake I showed that the motion at the bottom of the pit (which is ten feet in depth) was very much smaller than the motion on the surface. For very small earthquakes this distinction is not so marked ; the only difference between the move- ment below and that above is that the former has a longer period. Among the earthquakes which have occurred during the last few months several have been felt as short sharp bumps. On these occasions I have repeatedly noticed that a lamp hanging in the centre of my room acquires a rapid vibratory vertical movement, and there has been no per- ceptible swing. My impression with regard to these shocks, which are usually very short, is that they have an origin immediately beneath Tokio. The vertical motion of the disturbances we feel in Tokio is relatively to the horizontal motion extremely small, seldom exceeding the fraction of a millimeter. So far as Iam aware, it has never exceeded two or three millimeters, and the general rule is that vertical movement is but rarely recorded. In addition to the short sudden vertical movements, we have had others which have been characterised by their length and the slowness of their period. Such a disturbance occurred a few days before I left Tokio. At the time I was sitting at a table upstairs, when I fancied that I felt a movement. On looking up I saw that my lamp was swinging back and forth through a considerable arc. A disturbance of this kind would hardly be recognised as an earthquake by a person who had not been in the habit of recording such phenomena. III. The Earthquakes of 1885-1886. In my fourth report to the British Association I gave, in an epito- mised form, the results obtained by the observation of 387 earthquakes which had occurred between October 1881 and October 1883 in North Japan. A complete account of this work has now been published by the Seismological Society as Vol. VII. Part II. of their Transactions. Similar work, but extended to embrace the whole of the empire, has been under- taken by the Meteorological Department of this country, and results of a valuable nature have already been obtained. As this work is a continua- tion of that which has already been brought to the notice of the British Association, and as I have from time to time been consulted as to how it should be carried out, a brief account of the more important results which have been obtained may not be out of place. Professor K. Sekiya, who now holds the chair of seismology in the Imperial University of Japan, and who has had the immediate superintendence of these observations, will give a translation and fuller account of this work to the Transactions of the Seismological Society. The observations were made with the assistance of bundles of post- cards distributed with observers at 600 stations situated in various parts of the empire. During the year 1885 records were received at the Meteorological Department which formed the foundation for a series of maps showing the areas shaken by 482 distinct disturbances. On the average there were, therefore, 40 earthquakes per month, or 1°3 per day. The distribution of these disturbances according to months and seasons is shown in the following tables :— ON THE VOLCANIC PHENOMENA OF JAPAN. 417 January . . 32 July. ‘ . 82 February . . 44/Spring 113. August . . 29)Autumn 106. March ; SES September . 45 April : Jn WOU } October . 41 May - . 51}Summer 131. November . 51; Winter 132 June - = 43 December . 40 Cold Months , : ; , ; . 245 Warm Months . : : - : . 237 Total . : : - 5 . 482 The total area of ground disturbed each month is shown in the following table, which may therefore be regarded as an approximate measure of the intensity of seismic action each month : Square miles Square miles January . 60,000 July . . 55,000 February . 101000 Spring 205,000. August ; sso Autumn 178,000, March . 44,000 September. 87,000 April . . 28,000 October . 13,000 May . Z 62000 Samames 184,000. | November . 25,000 | Wists 107,000. June . . 94,000 December . 69,000 Cold Months x : ‘ é 312,000 Warm Months . : ‘ 2 362,000 Total . ; ; : 674,000 Disturbances shaking more than 30,000 square miles ‘ ap Saeed ” ” ” ” 000 ” ” . 6 ” ” ” ” 12,000 ” ” 13 ” ” ” ” 5,955 ” ” 9 ” ” ” ” 4,500 ” ” 12 ” ” ” ” 3,000 ” »” 17 ” ” »” ” 1,800 ” ” 24 ” ”? ” 1,260 ” ” 27 ” ” ” 600 ” ” . 63 a =“ less than 100 7 _ 319 Total , 492 The largest shock disturbed a land area of 34,700 square miles, Out of the 492 shocks 279 originated beneath the sea or near the sea- shore. The district most shaken is the alluvial plain near Yedo (Tokio). The eastern and southern part of Japan, or that portion of the country facing the Pacific Ocean, is shaken very much more than the western side facing the Japan Sea. The northern half of the empire, that is to say the country north of Tokio, is shaken very much more than the southern half. In Kiushiu, where volcanoes are numerous, earthquakes have not been so frequent as near the province of Kii, where there are no volcanoes, In two instances volcanoes and earthquakes appear to be related. Thus the earthquakes at the southern end of Satsuma occur at or near the volcanoes of that district, while the shocks at the north-east extremity of Honshiu occur at or near Osori-san. In the former district there were 9, and in the latter 24 local shocks recorded. In the centre of Honshiu, near to Tokio, volcanoes are very numerous, and it is in this part of the empire that there is the greatest seismic “eee and it may also be added, abundant evidence of recent elevation. . EE 418 REPORT—1886. The earthquakes, however, do not originate at the volcanoes. They origi- nate near the coast, where evidences of elevation are to be seen. On the opposite side of the island, where earthquakes are scarce, there are said to be evidences of depression. The Volcanoes of Japan. During the last year I have spent considerable time in arranging for publication the various notes which I have from time to time collected during the last ten years, relating to the volcanoes of Japan. Many of these I have personally visited and ascended. In the account which I am giving of these mountains, I am intercalating notes obtained from friends, together with the more important portions of some thirty or forty Japanese works specially describing volcanoes in this country. The chief results obtainable from this work are given in the follow- ing notes: 1. Map of Volcanoes. Among the more important results which have been arrived at has been the compilation of the accompanying map. For assistance other than that mentioned in the preceding pages I have to thank Mr. Tsunashiro Wada, Director of the Geological Survey, who has already drawn up a map of the volcanoes in Japan; Mr. N. Fukushi, Director of the Survey Department in Yezo; and my own private assistant, Mr. Matoba Naka. The following tables form a key to the map: Korite Isnanps. NovtTre.—There are therefore at least 23 well-formed volcanic mountains, and 16 mountains yet steaming in the Kurile Islands. Kurile is derived from the Russian hooreet, to smoke. The Aino name for the Kuriles also means The Smokers. Name Remarks Somewhat flat island. A well-formed cone. Erupted in 1770 and 1793. Height about 7,000 feet. Contains two well-formed cones and three or four less prominent peaks. Erupted 1737, 1742, and 1793. One cone steaming. 1. Shumshu . 2. Alaid 3. Paramushir 4, Shirinki A dilapidated cone and ridge. 5. Makanrushi Contains five or six rugged peaks rising from the mass. 6. Onekotan . Contains two well-formed cones. 7. Kharimkotan Contains one well-formed cone. Erupted 1883. 8. Shaiskotan Contains five or six peaks. Erupted 1855. Two cones steaming. 9, Ekarma Contains one fairly good cone and a ridge. 10. Chirimkotan Contains one fairly good cone. It steams, and lava occasionally flows. 11. Musisir — 12. Raikoke . Dilapidated cone. Erupted 1778 and 1780. 13. Matau ° A very well formed cone. Erupted 1878. Lava flows occasionally. Steaming. 14, Rashau Several rugged peaks. One peak steaming. 15. Ushishir One peak steaming. 16. Ketoy Several irregular peaks. Two are steaming. 16" Report £ wo a 0 Ss Fe VOLCANOES or JAPAN. Scale of English Miles | Nrike lines eee Tolcarnc Rocks =a i Active Volcanoes Gethioneids & CLD Landen, Mlustrating the 6% Report of the Committee appointed. to investigate the Volcanic Earthquake Phenomena of Tagua ON THE VOLCANIC PHENOMENA OF JAPAN. 419 Name Remarks 17. Simshir . 5 ; Three well-formed cones, Prevost peak being very noticeable. Violent eruption at the south end in September 1881. One peak steaming. 18. Makanruru : : = 19. North Brother . . | Two good cones. One dilapidated. Violent eruption May and June 1879, Two peaks steaming. 20. South Brother . . | One dilapidated peak. (The active peaks shown on the map refer to the North Brother, No. 19.) 21. Urup. : - . | Three good cones, with very many more or less conical peaks rising from the interior. Two peaks steaming. 22. Iturup - : . | Five good cones, with many imperfectly formed cones. Violent eruption in 1883. Two peaks steaming. 23. Kunashir . : . | One good peak. VOLCANOES OF YEZO. Height aa dent Remarks Name ‘1, Iwo-san . : = Active. There is here a cauldron of boiling mud and sulphur. The mountain is irre- gular in outline. 2. Kusuri . ; -| o> — 3. Oakan . : : — Regular:form. 4, Meakan . ; = Active. _ Regular. 5. Nisuikawoshipe .j} 7,000 | Betweén Nisuikawoshipe and Tourawoshi there ’ is a range of unnamed volcanic peaks, 6. Obutatishike . | 7,500. — 7 Zs 8 . Kushambitz . : Active. . Tourawoshi . é _— — a Gini é . | 3,450 a 10. Shokambitz . 5) ti — 11. Yubari . x : — Here there is a group of volcanic peaks, 12. Shakotan : = 13. Raiden . . . | 3,250 — | 14. Iwo-san - . | 3,600 | Active. 15. Shiribitz 5 : -- Active. Regular. 16. Iniwa . - : — Active. 17. Tarumai : : — Active. Volcanic cone eruption in the spring 1874, October 7, 1883, January 4, 1885, April 28, 1886. 18. Shiraoi . —_ #19. Usu. . f —_ Active. Well-formed crater. | 20. Noboribitz — Active. 21. Obira . F ee 22. Yurap . - . | 4,100 — | 23. Nigorikawa. . - | 2,700 — : | 24. Komaga-take - | 3,380 | Active. Volcanic cone regular.on north side; well-formed crater; eruption on June 27, 1710, September 26, 1856. 25. Hsan . . - | 1,920 | Active. Irregular. Sulphur deposits. 26. Rishiri . : : — 8 Se | 27. Oshima X F _ — 28. Koshima - — — Nore.—tThere are therefore in Yezo at least 28 volcanoes. Of these three or four are regularly formed and eleven are still steaming. RE2 SOT 26. 27. . Osori-san . REPORT—1886. VoLcanoes OF Honsuivu anp KivsuHiv. Name . Twaki-san . . Hakko-san . Herai-dake : . Nakui-dake “ . A mountain be- tweenNanashi- zure and Anhi- dake . A mountain west of Biobudake . Ganju-san . . Komaga-take . Moriyosh-zan . Mikoma-dake . Sukawa-dake . Chokai-zan Gas-san_ . : Arakami-yama . . A mountain to the N.W. of Arakami-yama . Neshiroishi - ya- ma Zoo-san .. A Kokuzo-san C Adzuma-san Adachitaro Bandai-san . . . Nasu-dake E . Shiowara - dake (Takahara) Nekko-san. P Hiuchi-dake Sumon-dake , yeel Nature of rocks . | 3,200 | Augite andesite with a little hornblende and quartz 5,260 aS 7,000 — 5,800 | Basalt and augite tra- chyte 7,100 | Basalt, augite ande- site with a little hornblende 5,800 | Augite andesite with a little quartz 6,300 aa 8,500 | Augite andesite and basalt / Remarks On Osore-san there is a sol- fatara. Yake-yama has a well-defined form ; a third crater is broken. There is a crater lake here. Last eruption 1848. Regular form. Crater somewhat worn. Three craters. One crater. Volcanic nucleus... Volcanic nucleus. * be, .. Volcanic nucleus. Last eruption 1824. Regular cone, with crater slightly steaming Regular cone. Well formed, with crater. Well formed, with crater. Well formed, with crater. Regular cone, with three craters. Volcanic nucleus. Two peaks (Arakami and Funagamine), and two craters. Volcanic nucleus. Crater and cone. Crater and cone, Volcanic nucleus. Four craters. One crater. Last eruption 807. Irregular mountain with old lava streams and broken crater. Covered with vegetation. A solfatara and boiling stream. In eruption about 1880. Crater and cone. Five craters. Nantai-san, Shirane-san(8,500),in erup- tion in June, 1872. Irre- gular crater. Komanako, Nyobo, Yu-dake,asolfatara. Cone and crater. Cone and crater. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. | 45. 46. 47. 48. 49, 50. 51. 52. ON THE VOLCANIC PHENOMENA OF JAPAN. 421 VOLCANOES OF HONSHIU AND KIUSHIU—continued. Name Komaga-take . Nayebaga-take . A mountainN.W. of Kusatsu Mioko-san . Yake-yama . Kurohime-yama Renge-san . Akagisan . Haruna-san Kusatsu-yama , Adzuma-san Asama-yama Miogi-san . Yatsuga-dake Raya-dake Tate-yama ‘ Iyakushi-dake . Yake-dake Norikurayama . Mitake Haku-san . ° Fuji-san . Ashidaka-yama. Hakone-yama , Amagi-san “ Height in feet 7,953 10,447 10,000 8,947 12,400 4,474 4,700 Nature of rocks Andesite . Augite andesite hornblende, (dacite) ande- Quartz, andesite hornblende, site Augite andesite, with a little olvine Augite andesite Basalt with augite an- desite with a little hornblende Granite near base. Augite andesite, with hornblende, also with quartz Andesite . . P Augite andesite, with hornblende Obsidian, perlite, au- gite andesite, with hornblende Half-way up sand- stone. Augite ande- site with quartz Anorthite, basalt Basalt and augite andesite Obsidian, augite an- desite, basalt Remarks Cone and crater. Cone and crater. Cone and crater. Two craters, one a solfatara. Cone and crater; near the top a solfatara. No lava, well formed. Cone and crater. Two craters; Renge and Nosi-kusa. Two craters, one broken. A crater lake. A crater lake. five craters, Altogether A solfatara. Three craters with walls to form lakes. Sulphur de- posits. Cone and crater. Wellformed. Three craters; one, which is very deep, is steaming violently. Last eruption about 1870. Volcanic nucleus (7). Two cones and craters (Yat- sugadake ard Tate-shima). Volcanic nucleus. Two craters broken. Solfa- tara, irregular form. Last eruption 704. A complete crater. Three cones and craters (Yake-dake, Kasa-dake, Iwo-dake). Near top a sol- fatara, well shaped, no lava. Three craters with lakes on top. Black scoria and lava flows. Five craters. Weathered and rugged on the top. Two craters and solfatara. Craters with water, sul- phur deposits. Last eruption 1707. Regular form, with a crater 600 feet deep. A little steam escapes. Two craters. Three craters (Kamuriga- dake, Komaga-dake, Fu- tago-yama) crater lakes. 422 REPORT—1886. VOLCANOES OF HONSHIU AND KiusHIuU—continued. Height Name oe Nature of rocks Remarks in feet 53. O-shima . - | 2,500 | Augite andesite . | Last eruption 1876. Crater gives off steam. 54, Nii-shima . - | 1,400 —_— —_ 55. To-shima . S| eA) —_ == 56. Miake-shima. . — _— Last eruption 1876. Black flattish cone. 57. Mikura-shima — —_— — 58. Hachijo . - | 2,840 ; —_— Last eruption 1789-1801. 59. Aoga-shima .|] 1,500 — Distinct crater. Vegetation on the cone and in the crater. 60. Daisen . ; — Augite andesite . | Cone and crater. 61. Mikame-yama . — — Cone and crater. 62. Futago-yama . — — Cone and crater. 63. Tsumuri-san. . — — Last eruption 867. Five cra- ters and peaks, one solfa- tara. 64. Hiko-san . < — — Volcanic nucleus. 65. Kiucho-san ‘ — — Four cones and craters (Ku- rodake, Kiuchosan, Waiita- yama, a solfatara). 66. Aso-san . . | 5,000 | Augite andesite, ba- | Large crater 10 miles diame- salt ter. Central cone steaming. 67. Tar-dake . : _- — Broken crater. 68. Onsen-dake : — Hornblende andesite | Broken crater and solfatara. with a little quartz | Last eruption 1791. Irre- gular form. 69. Kirishima-yama | 4,816 | Augite andesite . | Last eruption 1772. Well formed, Eleven complete craters. 70. Sakura-jima .| 3,060 | Augite andesite glass | Three craters. 71. Ikeda-yama . | 3,069 | Augite andesite . | Four craters (Kaimon-dake, two solfataras). 72. Hirakiki-yama . — _— Last eruption 1615. 73. Twoga-shima. . | 2,331 — These islands are yet active. Yerabu-shima .| 2,297 ° . There: are other islands in Naka-shima . | 3,400 the chain stretching to- Kaminone. , 972 wards Formosa, of volcanic Yoko-shima .]| 1,700 origin. Iwo-shima : 541 In Honshiu, Kiushiu, and the southern islands there are at least seventy-eight volcanoes. Out of these about twelve have wéll-formed cones and twenty-four are still steaming. 2. Number of Volcanoes. Because Japan has not yet been completely explored, and because there is considerable difficulty in defining the kind of mountain to be considered as a volcano, it is impossible to give an absolute statement as to the number of volcanoes in this country. If under the term volcano we include all mountains which have erupted within the historical period, those which have a true volcanic form, together with those which still exhibit materials on their flanks, which have been ejected from a crater, traces of which can still be seen, we may conclude that there are at least ON THE VOLCANIC PHENOMENA OF JAPAN. 423. 100 such mountains in the Japanese empire. These mountains are distributed as follows: Northern Region rae MOI Ee Cale is RR a CoS Ng Northern Honshiu Central Region {entra Honshiu Oshima Group ‘Southern Honshiu . - : : - « A Southern Region ; Kiushiu ) 13 Southern Islands J : . 35 Total . : : 100 If we add to our list the ruins and basal wrecks of volcanic cones, this number is considerably increased. The number of mountains which are easily recognisable as being of volcanic origin as given in the map is 129. Of this number about 51 are still active, that is to say, are now giving off steam. These active volcanoes are distributed as follows : Northern Region egg ; 4 : - : : - 27 Central and Southern Region . : - : : . : . 24 Total . : : 2 . 51 Ont of the 129 volcanoes, 39 are symmetrically formed cones. The greatest proportion of regularly formed mountains and of mountains yet giving off steam are in the Kuriles. From this it may be argued that the mountains in the north are younger than those in the middle and south. 3. Number of Eruptions. Altogether in the preceding pages about 233 eruptions have been recorded. The distribution of these in the different districts, and with regard to time, is shown in the accompanying table. The greater num- ber of records in the southern districts, as compared with the northern districts, may be accounted for by the fact that Japanese civilisation advanced from the south. In consequence of this, records were made of yarious phenomena in the south, while the northern districts were un- known and unexplored regions. The greater number of eruptions have taken place in the months of February and April. Comparing the fre- quency of eruptions in the different seasons, the volcanoes of. Japan appear to have followed the same law as the earthquakes; a greater num- ber of eruptions having taken place during the cold months. This winter frequency may possibly be accounted for in the same manner that Dr. Knott accounted for the winter frequency of earthquakes. During the winter months the average barometric gradient across Japan is steeper than in summer. This, coupled with the piling up of snow in the northern regions, gives rise to long-continued stresses, in consequence of which certain lines of weakness of the earth’s crust are more prepared to give way during the winter months than they are in summer. 424 REPORT—1886. Eruptions in Relation to Months and Seasons. Aso-san Sakurajima. Kirishima . “ Tsumuri-zan j Onsen-dake Islands near Satsuma. Hirakiki-yama Kiushiu District . Vries Island Group Fuji-san . Asama-yama Tate-yama . Natsu-yama Ganju-san . Iwaki-zan Central District YEZO :— Komaga-take Tarumai KURILE ISLANDS :— Alaid . : A Paramushir. : akanrushi haiskotan . Ikarma F Chirimkotan Matau. : A Raikoke . : Rashau ; Ushishir Ketoy. Simushir Brat Chirnoi Urup . Iturup Kunashiri Northern District Total Sourvern District. rey ey a3. |e F, ls glalelelelelele lelelelelslg BASSE 15/5] 2)2/0/4 18) le 2112/2/5/3/2/4/8|/4/2)619] 8167 Sy Le 4) 1 | hoe la? | ea eoe Rom en ite | \ia7 meee ee | EE | =e pee oe ena = = me ey ee ees — | — | — | —) — | —} — | — J —] —} 1 J—|—) 1 (| eS a | iat alee"! at | 83 lat ey ||) | ela oe ee i Saale | LO) ee lu sislerraa ile 10] 5 12] 13 | 36 138 CENTRAL DISTRICT. 1{/1/2/—|1|—]2/1]—{—|1]2]7]18 |b Fr Nast See Pi el as fe Sr ov TTL em] At De aa ig | et) | | | 5 a ss eS ee 1-4 —} 3 |—|—)}— | — | — |} —J— J — 1 |—j—| 2 iL |] Thee — = =) || il 5)5 |) 4/10; 2/2) 4/3 )—) 1) 4] 4 119/63 NortrHern District. aie era ea Sy eo Le Dean este — || | 4 Ne i | | ee eS 2 a Nal | eal en a es || 4 S|) a A Yee || a 1 SSE 4s ] Se Se. 2 pene a Ye fp | eb) pe es | or | 1 me ED Le) |S | ae a | Oe eS Sa | a | 2 Petr | eee | | fee || Seg) Women| (EE | Pee od POE eee 1 eH FS ES || | FE BU ES I 2 ee a =| | | 1 =| eee | | | es) 1 ee | ene | ee | ees) en eee et 1 ES ee) | a ey) Se ee }4 fe seg Se eae | Se) set ee ee ee | 2 ee fe es eg (ma ee (oe eer pre fg) 2 ee [S| PR PP | I |e i) et fees ema pa A lite hs |e a = 1 1) 8) =] El |e | hee 10 21; 9 |21| 9 6 11 16/11| 7 |16 233 Winter Months, 80; Summer Months, 73; Unknown, 80: Total, 233. ON THE VOLCANIC PHENOMENA OF JAPAN. 425 4, Position and Relative Age of Japanese Volcanoes. The youngest of the Japanese volcanoes appear to be those which exist as or on small islands. On the islands in the Kuriles, in the ‘Oshima Group, and in the Satsuma Sea, many of the volcanoes are yet young and vigorous. Further, many of these islands have been formed during the historical period. The island-forming period in the Satsuma Sea occurred about the year 1780. Looked at generally, the volcanoes of Japan form a long chain running from the N.E. towards the S.W. A closer examination of the distribu- tion of the volcanic vents shows that there are probably four lines. 1. The N.E.S.W. line running from Kamtschatka through the Kuriles and Northern Yezo. 2. The curved line following the backbone of Honshiu and terminating on the western side of the Yezo anticlinal. 3. The N.N.W. S.S.E. line of the Oshima Group. This line, coming from the Ladrones, passes through Oshima and Fujisan parallel to and near to the line of a supposed fault. Here it intersects the main line running through Honshiu. Volcanic vents are here very numerous. As the Honshiu line is intersected, while the Oshima line is the intersector, it may be argued that the Oshima-Fujisan line of volcanoes are younger than many of those on the Honshiu line. 4. The Satsuma line, coming from the Philippines through Sakurajima and culminating in the famous Mount Aso, which is the nucleus of Kiushin. 5. Lithological and Chemical Character of Lavas. Although I have made an extensive collection of the voleanic rocks of this country, opportunity has not hitherto presented itself for their examination. I can therefore only speak of them in general terms. They are now, I believe, being carefully studied by the officers of the geological survey of Japan. The rocks in my possession are chiefly andesites. Those containing augite, like the rocks of Fujisan, as pointed out by Mr. Wada, the director of the geological survey, closely approximate to basalts. True basalt is, however, rare. Another common rock is horn- blende andesite, some of which contains free quartz. Quartz trachytes occur in the north of Japan. The following table, which is chiefly drawn up from material kindly placed at my disposal by Mr. Wada, shows the percentages of silica, ferrous and ferric oxide contained in the rocks of ten volcanoes : PERCENTAGE OF SI0., FEO AND FE., O, IN THE VOLCANIC ROCKS OF JAPAN. Locality Sio.2 FeO Fe.. O; 1. Norikura . E : : : : : 61.72 1.35 3.50 2. Mitake : : 5 59.97 3.27 3.86 3. Kusatsu (near Zi goedo Amiguehi) 3 - 61.49 3.30 4.35 4. Amagi(Hakone) ~ . . : 65.34 2.45 3.09 5. Komagadake ., : ; , : - 56.27 2.19 6.69 6. Moriyoshisan . s : - 4 ay hyp OGaLa 2.65 4.15 =e | (60.64 3.81 3.14 ee noses Pee 2H -| Lea ns 5.19 4.49 8. Hakone (Tonosawa) . 2 * ; : 48.97 4.02 4.81 9. Fujisan. ; : ; : : 49.00 5.1 6.06 10. Oshima . : ; . 3 : Wee e2 0) 13.70 (?) — 426 REPORT—1 886. One feature exhibited by the table is, that the rocks of Oshima, Fuji- san, and Tonosawa are basic, while those like Chokaisan and Moriyoshi- yama, belonging to the Honshiu line of volcanoes, are relatively acidic. More extended observations of this description may show that different lines of volcanoes have erupted different lavas, or that the lavas of different constitution are of different ages. 6. Magnetic Character of Rocks. Mr. E. Kinch, when speaking of the soils in the neighbourhood of Téky6, makes special reference to the magnetite they contain. A great portion of this comes from the disintegration of volcanic rocks. Many of the Japanese lavas have a distinct effect upon a compass needle. The black lavas from the crater of Fujisan will deflect the needle of an ordi- nary compass through 180 degrees. Many of the pieces of lava are not only magnetic, but they are polar. Dr. EK. Naumann found a block of augite-trachyte on the top of Moriyoshisan which would deflect the needle of a compass through 155°. The most curious observation made by this investigator was that the magnetic declination near to Ganju-san has during the last 80 years (when it was about 14.30 EH.) decreased 19°, it now being about 5° W. As we recede from this mountain the amount of change has been less- Assuming this result to be correct, it would seem justifiable to look towards Ganju-san as connected with these local changes. Some of the volcanoes in the Kuriles are said to exert a marked influence upon the compasses of ships. When a vessel is lying near certain mountains, as for instance in Bear Bay, at the north end of Iturup, a distant mountain has a very different bearing to that which is indicated by the same com- pass when the vessel is a short distance outside Bear Bay. In both cases the ship may be lying in the same direction, and the direction of observation is practically along the same line. This leads me to repeat a suggestion that I have several times made during the last few years, namely, that a magnetic observatory bé esta- blished on or near one of the more active volcanoes of this country. Many of these volcanoes, like that of Oshima (Vries Island), lie in the track of so many vessels that to determine whether local and rapid changes in magnetic declination are taking place in these localities appears to be a legitimate investigation. Changes in volcanic activity are pro- bably accompanied by local changes in the magnetic effects produced by subterranean volcanic magmas. These changes may be due to alterations in position, alterations in chemical constitution, and changes due to the acquisition or loss of heat. If such is the case, the records of a magnetic observatory would lead us to a knowledge of changes taking place beneath the ground. When we remember that volcanoes like Oshima (Vries Island) lie in the track of so many vessels where it seems probable that there may be local and rapid changes in magnetic variation taking place, it seems that the suggested investigations have a practical as well as scientific aspect. An investigation of earth-currents at and near volca- noes might be added to the magnetic investigations. 7. Intensity of Eruptions. Judging from the accounts of eruptions which have been given in the preceding pages, it would appear that the intensity of volcanic action in ON THE VOLCANIC PHENOMENA OF JAPAN. 427 Japan has been as great as in any other portions of the world. One period of unusual activity was between the years 1780 and 1800, a time when there was great activity exhibited in other portions of the world. It was during this period that a portion of Mount Unsen was destroyed and from 27,000 to 53,000 persons perished; that many islands were formed in the Satsuma Sea; that Sakurajima threw out so much pumiceous material that it was possible to walk a distance of 23 miles upon the floating débris in the sea, and that Asama ejected so many blocks of stone, some of which are said to have been from 40 to over 100 feet in diameter, and a lava stream 68 kilometers in length. 8. The Form of Voicanoes. The form I particularly refer to is the regular so-called conical form, which is very noticeable in many of the Japanese mountains, especially perhaps in those of recent origin. Outlines of these volcanoes, as exhibited either by sketches or photographs, show curvatures which are similar to each other. In the Kurile IslandsI have had opportunities of comparing two volcanoes by so altering my position until one of the mountains partially eclipsed another standing at no great distance in the background. One of these mountains was Otosoyama (Mount Fuss). The other mountain, like many of the peaks in the Kurile Islands, is without a name. From a collection of photographs, I traced the profiles of a number of important mountains in this country. These profiles are repeated in this paper. From an examination of these figures I found that the curvature of a typical volcano was logarithmic, or in other words the form of such a mountain was such as might be produced by the revolution of a logarith- mic curve round its asymptote. In my original paper on this subject I said that the form agreed with that which would be produced by the piling up of loose material. As pointed out by Mr. George F. Becker, in a paper on the form of volcanic cones, &c. (‘ American Journal of Science,’ October 1885), I ought to have said it was the form due to a self- supporting mass of coherent material. Mr. Becker continues my observa- tions by an analytical investigation of the conditions of such equilibrium. If the height of a column is a, its radius y, the distance of any horizontal plane from the base 2, the specific gravity of the material 7, and the co- efficient of resistance to crushing at the elastic limit £, then the equation of the curve which, by its revolution about the a axis, will generate the finite unloaded column of ‘ least variable resistance ’ is Qk r Where c = This latter quantity is of course different for different materials. It can be expressed in terms of z and y 2h y r (tan’d—1)4 d being the angle which the tangent at any point makes with the « axis. A428 REPORT— 1886. The value ¢ can be obtained from photographs or drawings of a mountain, while + may be obtained from pendulum experiments or from specimens of volcanic material. With these data we can determine the modulus of resistance for the elastic limit of the materials which com- pose a mountain on a large scale, for many constituents of the earth’s crust. Mr. Becker concludes his observations by remarking that a peg of the form and dimensions of lunar volcanoes would lead to values of = whence we might approximately determine whether the lunar lava is similar to that of terrestrial origin. In the following table I have followed out Mr. Becker’s “iw and calculated ‘ the modulus of resistance to crushing at the elastic limit in lbs. per square foot for a number of Japanese mountains.”! The different values for ** for the same mountain are in great measure due to my not being able to obtain an accurate scale for the various photographs which had to be investigated. Another difficulty was obtaining a value for r or the density of the mountain. Professor T. C. Mendenhall, who made a number of experiments with pendulums on the summit of Fujiyama, says the rocks of that mountain have a density of 1.75. This is when they have air in their pores. As powder, the density becomes 2.5. Wada gives the specific gravity of the rock on Fujisan as 2.6. Assuming the density of the earth at 5.67 (Bailey) then the density of Fujisan, as de- termined by Professor Mendenhall’s experiments, is 2.08. In my calcu- lations for the following table I have assumed a density of 2.5 for the materials of all the mountains mentioned. oe Height 2 a pee eater Kind of profile in feet a > pe ae: examined Fujisan. . . . .| 12,441 4,200 oe ~~ | Photograph. — 5,000 — a= Photograph. — 4,240 -- _- Photograph. —- 3,500 — — Photograph. — 5,420 on 5,450 } = Photograph. — 5,440 — —— Photograph. — 3,945 Ry 4.133 } — Photograph. — 4,430 — — Surveyed section. — 3,640 — — Surveyed section. Average for Fujisan — 4,490 2,245 350,220 — Iwaki-can . . . .| 5,260 2,360 1,180 174,080 | Photograph. Nantai-san. ... 3,800? | 2,000 1,000 156,000 | Photograph. : 7,773 | 2,195 : ENG ie Sted Seopa = 2199} | 3,078 | 163,168 | Photograph. Krakatoa (Java). .| 2,745 | 1310) | 655 | 102,180 | Surveyed section. Comparing the results given in the above table with the numbers in the following table, which are based on experiments referred to in Ran- 1 It will be noticed that there is difficulty in defining the quantity = , as caleu- Tr Jated from the shape of a mountain. It isassumed that the materials are not crushed. 3 This is the height above Lake Chuzenji. ON THE VOLCANIC PHENOMENA OF JAPAN. 429 kine’s ‘ Civil Engineering,’ we may say that the average strength of Fuji- san lies between that of rubble work and sandstone. Iwaki-san, Nantai- san, and Alaid are like good rubble masonry, while the strength of the ill-fated Krakatoa is not much above that of ordinary brickwork. In making the above calculations I have used: 1. The profiles of voleanoes traced from photographs which I used in my original communication on the forms of volcanoes published in the * Geological Magazine.’ . 2. A series of tracings from photographs of Fujisan and other moun- tains not hitherto published. For most of these a scale can be obtained. The best scale for Fujisan is probably the difference in height of Hoyei- san and the summit. - Hoyei-san is a parasitic crater on the southern side of Fuji and in the profiles is marked H. This difference in height is about 4,137 feet. A scale may also be obtained from the line of sea-level or from the diameter of the crater, which is about 750 metres. Two profiles of Fujisan from the surveys of Mr. O. Schiitt are also given. Causes modifying the natural curvature of a mountain and therefore interfering with the above calculations are: 1. The tendency, during the building up of the mountain, of the larger particles to roll farther down the mountain than the smaller particles. 2. The effects of atmospheric denudation which carries materials ‘from the top of the mountain down towards the base. 3. The position of the crater and the direction in which materials are ejected. ‘ 4, The existence of parasitic craters on the flanks of a mountain. 5. The direction of the wind during an eruption. 6. The sinking of a mountain in consequence of evisceration beneath its base. 7. The expansions and contractions at the base of a mountain due to the acquisition or loss of heat before and after eruptions. 9. Theoretical Mountains. As it might be interesting to compare actual mountains with theo- retical mountains constructed from the equation y=‘ ie _ such mountains have been drawn. The values of ¢ are given in the following table : Instantaneous : Crumblin, Weight, Material breaking strength S k Cubie c= 2h strength in Ibs, ibs foot Ibs r per sq. foot ae : Granite co : i hi 1,584,000 1,580,000 170 18,500 Sandstone . . j ; 790,000 590,000 144 8,200 Rubble masonry . ‘ - 316,000 150,000 120 2,500 Brickwork . 3 4 ; 144,000 72,000 112 1,300 a Ee Sah ee ee eee eT ee In drawing up the table, I have taken the instantaneous breaking strength of granite and its crumbling strength, which is the largest 430 REPORT —1886. possible value for k, as being equal. For sandstone I have assumed the crumbling strength as being three-quarters of the breaking strength, while for rubble work and brickwork it has been taken as one-half. (See Rankine’s ‘ Civil Engineering,’ p. 361, &c.) The diameter of the base of each of these mountains is 48,000 feet, and the height to which mountains of the following different materials could be built upon such a base without crushing would approximately be: Brickwork . s 5 ‘ 3 f J : . 4,600 feet. Rubble masonry . . " 5 . 3 3 = 91,800) +.3, Sandstone . 7 ; : 3 F : A . 14,500 ,, Granite - 4 4 ; A F . : - 20,000 ,, 10. Effect of Volcanic Eruptions on the People. From the translations of Japanese works relating to voleanoes which I have given, it is seen that the eruptions of these mountains have from time to time exerted a very marked influence upon the minds of the Japanese people. Divine interference has been sought to prevent erup- tions, priests have been ordered to pray, taxes have been repealed, charities have been instituted, special prayers against volcanic disturb- ances have been formulated and have remained in use for the period of one hundred years, while special days for the annual offering up of these prayers have been appointed. At the present day there is a form of worship to mountain deities not uncommon, which may have had its origin through the fear created by volcanic outbursts. Displays of volcanic activity have certainly intensified this form of worship. Conclusion. In conclusion to this report, it gives me pleasure and satisfaction to testify to the great work which has been accomplished, and the great interest which is still being displayed in connection with seismological investigation in this country. Professor Forrel, of Switzerland, speaking at the Institution of Civil Engineers, testified to the great merit of the work which has been accomplished in Japan, and remarked that the observers of seismographs in that country had in two years accomplished more than twenty centuries of Kuropean science had been able to show (‘ Minutes of Proceedings of the Institution of Civil Engineers,’ vol. lxxxvi., session 1885-6, part 1, p. 40). Inasmuch as the grants of the British Association have in no little measure assisted towards whatever may have been done in Japan, it cannot fail to be of interest to the members of that Asso- ciation to know the extent to which they have rendered assistance in advancing seismological science in Japan. With the assistance of the British Association, an extensive series of experiments lasting over several years were made upon artificially pro- duced disturbances, which led to an insight into the nature and method of propagation of earth-vibrations. It was with the assistance uf the British Association that a general seismic survey was made of North Japan. One result of this work has been that the Imperial Government of Japan has extended similar observations over the whole empire, and now there are about 600 stations at which earthquakes are recorded. The first complete seismograph made under the auspices of the British Asso- ciation has been reproduced in this country, and is now being gradually distributed throughout the empire. ON THE VOLCANIC PHENOMENA OF JAPAN. 431 The Imperial University has endowed a chair of seismology, which is held by Mr. K. Sekiya, an indefatigable worker at earthquake phenomena, and has established a well-equipped earthquake observatory. The Imperial Meteorological Department has also established an observatory, at which, in addition to the ordinary work of observing, they make and test instru- ments to be used in the country. In these and other ways is Japan working at a study which for many years has made but little progress. One valuable work towards which the Government of this country is at present directing its attention is, how and where to construct buildings which either partially or wholly may escape the effects of earthquake movement. With these few general remarks on what is being accomplished in Japan, the members of the British Association will recognise that their endeavour to give an impetus to scientific investigation in the far Hast has not been unsuccessful. The Modern Development of Thomas Young’s Theory of Colour-vision. By Dr. Arruur K6nie. [A communication ordered by the General Committee to be printed in extenso among the Reports. ] § 1. In the third book of his ‘ Optics’ Isaac Newton puts the question, whether the sensation of colour is brought about by some sort of vibrations which the light produces in the constituents of the retina. In a paper read before the Royal Society of London in 1801 Thomas Young makes an observation bearing upon this statement of Newton, in which he points ont that the number of those vibrations depends on the nature of the above-mentioned constituents. The infinite number of perceptible colours requires an infinite number of various constituents in each surface element of the retina. This is an impossible supposition. But we can explain all phenomena of colour-per- ception by supposing that each surface element of the retina consists of three constituents, each of which, when affected, causes a different colour- sensation. On this supposition all the various shades of colour areresultants of three fundamental sensations originating in those constituents. Later on Thomas Young proposes red, green, and violet as these fundamental sen- sations. It is true that he does not explicitly say that the sensation of white is the resultant of the simultaneous action of all the three consti- tuents, but this is a self-evident conclusion if his supposition is to explain the famous experiment of Newton. The principle which he intuitively laid down for the more limited field of the theory of colour-vision was, a quarter of a century later, brought out again by Johannes Miiller under the name ‘ the law of specific energy of the organs of sensation’ (‘ Gesetz der specifischen Energie der Sinnes- organe ’), and proved to hold good for the whole field of physiology. It is little known that the msight of Thomas Young had evena greater depth. He had already explained that the confusion of colours, which his contemporary Dalton made, was a consequence of the absence or paralysis 432 REPORT— 1886. of those fibres of the retina—as he calls them—which are calculated to perceive red. Thus the theory of colour-vision, accepted up to the present date, was already established in principle. The knowledge of facts was too meagre as yet to prove the ideas of Thomas Young, and, therefore, they were gradually more and more dis- regarded, It was not until thirty years ago that Maxwell and Helmholtz saved them from utter oblivion. The former even attempted an experi- mental quantitative demonstration of the truth of these ideas. The methods and the results of Maxwell’s investigations are too well known to be specially dwelt upon here. But we must specially dwell upon this point, that at the same time Helmholtz most emphatically de- clared that colour-blindness (which in the meantime was better studied) was the result of the absence of one fundamental sensation, although he did not know Thomas Young’s ideas on this point. The results of Maxwell’s investigation must be greatly valued, because they contained the first measurements with spectral light; but for the very same reason, that they were the first, they could not be such that. final conclusions could be drawn from them. During the last ten years—that is, twenty years after Maxwell’s in- vestigations—the well-known scientists Kries, Frey, Donders, and Lord Rayleigh, supplied with greatly improved instruments, carried out more exact measurements, which, however, extend only over certain parts of the spectrum. These facts, and the circumstance that great facilities were offered at the physical laboratory of the University in Berlin for investi- gations of this kind, induced me to take up these measurements and to extend them over the whole spectrum, and they were finally carried out by me and my colleague Dr. Dieterici. § 2. The investigation must begin with the reduction of the infinitely large number of colour-sensations to the smallest possible number of elementary sensations, which by their intensity and mutual relation produce every possible kind of colonr-sensation. This is a purely experimental problem, whose solution can and will be made independent of every theo- retical hypothesis. This is the reason why we choose the expression ‘ ele- mentary sensation’ and not ‘fundamental sensation,’ because the latter expression usually refers to a simple process going on at the terminal of the optical nerve. This distinction is necessary, as will appear later on. The first important simplification of our problem is afforded by the fact that in the case of every individual we can produce every sensation of colour by spectral light and their mixture. It seems expedient here to lay down the following definition: given that the distribution of light in our spectrum is such as we have it in a diffraction-spectrum, then we shall call ‘ curves of elementary sensation’ those curves which determine the intensity of elementary sensation for any given wave-length. Having premised this definition we can at once proceed to a brief description of the apparatus. It is an apparatus constructed by Prof. Helmholtz for mixture of colours, and on this occasion improved by us in many details. Itis a spectroscope with an equilateral prism P (fig. 1), and two collimators CC; the telescope T having instead of the eye-piece a slit S, at the focus of its object-glass. Each collimator contains an achromatical iceland-spar J, and in front of the slit a Nicol N ; but for the present we shall disregard these additions to the collimators. The slits S, and S; being illuminated ON THOMAS YOUNG’S THEORY OF COLOUR-VISION. 433 we shall evidently have two spectra at the slit S,; superposed one over the other. An eye placed close before the slit S, sees a Fie. 1. picture like fig.2. A little consideration will make it plain to us that the colour- ed parts in the figure are the two faces of the prism shining with that light, which coming from them passes through the slit S, to our eye. Let us consider the effect of placing the ice- T Si land-spar between the slit and the object-glass of the collimator. This effect will be that in general we shall have two pairs of spectra at S,, one pair due to slit S,, the other due to S3, and that the lights of one pair belonging to the same slit will be polarised perpendicularly to each other, It is evident that an eye placed close before the slit S, will see the same picture as Fie, 2. before, but now we do not see in each half monochromatic light, but a light which is the resultant of two component lights, and now the object of interposing the Nicol between the slit and the source of light is simply to vary the ratio of these two components to each other. When the iceland-spar is quite close to the slit we have monochromatic light in the corresponding half of the picture. In this manner we can compare mono- chromatic light with monochromatic, a mixture (The two parts of this figure, of two components with monochromatic and which are differently hatch- two such mixtures. This comparison consists in uy cleat} to be, diffar- producing the same shade of colour and the same " ' intensity in each half of our picture, which gives us a colour-equation. A great number of such colour-equations was made by those persons whom we examined. The coefficients and variables of the equation are given by the position of the collimators, the distances between the iceland-spars and the slits, the positions of the Nicols, and the micrometrically measured width of the two bilateral slits. The source of light was a specially constructed gas- lamp, so that our direct results had, of course, reference to the prismatic spectrum of a certain kind of gaslight. But in order that they should have a general character we calculated what they would have been if we had employed a diffraction spectrum of sunlight. Of course I cannot think of entering upon the description of a great many and very interest- ing details of our proceeding. I shall therefore pass over directly to the results of our investigation. § 3. (a) There are persons who can distinguish no different shades of ae and therefore the world, as far as colour is concerned, appears to 1886. FF 434 REPORT— 1886. them like an engraving or a photograph to us. Such persons, whose number is very small, have one elementary sensation only. I have met one such a person, and the curve of elementary sensation which we obtained from him is the curve H in fig. 3. Professor Donders has made Wels the same curve for aon’ another similar in- dividual and has ob- tained almost iden- H tical results. So that we may regard this [ as a typical form for monochromatic co- lour-systems. / \ (6) There is an- other very numerous class of persons, generally called co- J es : A Ss \ lour-blind, in whose Siiior sR os Lon Heh G H case we can divide the whole spectrum into three parts. The parts near the ends we shall call “boundary regions’ and the parts between them the ‘intervak’ For these persons each boundary region has its own light, varying in intensity only but not in colour, and the colour of any part of the interval they can produce by the mixture of the light of two parts, one from each boundary region. Here we must assume two elementary sensations, and the simplest way to analyse the colour-system of such persons is to take the sensations of the boundary regions as elementary sensations. On these assumptions we have determined the curves of elementary sensations for this class of ersons. ; We have obtained three different curves. The curve K in fig. 3 was obtained from every person but the other curve was different with dif- ferent persons. Some had the curve W,, others had the curve W,. So that as far as our own observations go we must distinguish all the colour- blind into two classes, and two classes only. A third very different class of the colour-blind was found by Professors Holmgren and Donders. But their analysis was a qualitative one only. For the purpose of simplifying calculations, which I shall mention later on, the curves were drawn in such a manner that the area bounded by them and the axis of absciss should be the same for each curve. So far we have two large classes of persons, and we have seen that the small number of persons belonging to the first class possess one elemen- tary sensation only, whereas the large number of persons belonging to the second class possess two elementary sensations, and we have also seen that this class must be subdivided into two divisions or types. (c) Now we pass over to the third very large class, which includes all persons not belonging to any of the two preceding classes. We shall presently see that if in the case of these persons we assume three elemen- tary sensations, we shall be able to explain all colour-equations made by them. It has been found by Lord Rayleigh and Professor Donders that the persons of this class differ from each other considerably, and that this class, too, must be divided into two subdivisions at least; the persons belonging to the first subdivision forming the great majority of this ON THOMAS YOUNG’S THEORY OF COLOUR-VISION. 435 third class, whereas the persons of the second subdivision are not more numerously represented than the persons of the preceding class. A person of this third class on examining the spectrum finds two boundary regions situated similarly as in the preceding class, and we assume, as we did before, that the colour-sensations of these regions are elementary sensations. The parts from the boundary regions to a certain distance towards the middle of the spectrum we shall call the ‘boundary intervals,’ and the remaining part between them we shall call the ‘ central interval.’ The colour-equations have shown that in each boundary in- terval we must assume two elementary sensations, one which is the same for both, whereas the other is the elementary sensation of the adjoining boundary region, and similar equations have also shown that any colour of the central interval is the result of the three elementary sensations already found, that is, the sensations R, G, and V. I would like to mention here that only such colour-equations could be used, in the case of which the colours as to their hue and saturation could be easily matched, and in whose combination the errors of observation had no great influence upon the results of calculation. To obtain the first object whitish colours had to be avoided, and only neighbouring parts of the spectrum had to be mixed; whereas to obtain the second object the component parts of the spectrum had to be at a considerable distance from each other. This, of course, places the experi- menter in a sort of dilemma, and many thousands of colour-equations had to be produced before the proper ones were obtained. The continuous curves R, G, and V (fig. 4) belong to the first sub- division of this third class, and the two dotted curves together with the curve V belong to the ag second subdivision. I Or shall henceforth de- note the colour-sensa- tions of the first sub- division as the normal, and those of the second as the abnormal. § 4. Having accom- plished the analysis of colour-sensations with- out the assistance of any hypothesis let us consider whether we can draw any inferences as to the physiological process which produces the sensations of colours. Following the above-mentioned usual definition, we shall call that sensation, which is caused by a simple process at the terminal _ of the optical nerve, a ‘ fundamental sensation.’ It is evident that for every person the number of fundamental sensations is equal to the number of elementary sensations, and that we can speak of ‘curves of fandamental sen- sation’ just the same as we did before of curves of elementary sensation. We shall employ the following symbols for fundamental sensations :— For the first class second ,, wigs 1 oo Eb F GiB H first type 8), &, second ,, 2) be ’ normal K, G, B ” ” third ie } tiers a ’, B! PP) 2? FF2 436 REPORT—1 886. All colour equations are known to be linear and homogeneous, and since both the elementary and the fundamental sensations are the solutions of these equations it follows that the fundamental sensations of every person must be homogeneous linear functions of his elementary sensations, and vice versé.. We know the elementary sensations, and hence we can write the following relations : — Ibs § =H IL. (1) @,=a,;' W, +8,’ K, where a,’ +,' =1 RK, =a," W, +8," Ky ty By (2) W =a,’ Wetfho K, 5, ao! +P’ =1 Ko=a5" Wetfho"” Ky 4 a’ +8,’ =1 Ill. (1) R=a,'.R +b,'.G +¢,'.V wherea,’ + 0,’ +e) = @ =a," RK +6,".6+¢,/V 4, ay” + by” +6," =1 5) cee +6,/"G +¢,/"V sf ail + fii tN — | (2) BS'=a! B eb G +e! V'*,, a! +o! te = G’ Oe R/ +6," G’ +c," Vv’ i ae + [ya +c,!' =I] Ht’ =a Ry +6," Giecliiy' a all + (ose +¢,/"=1 By means of these equations we can construct curves having the same relation to fundamental sensations as the others had to elementary sen- sations. The object of this superposition is to examine whether among the infinite number of possible curves of fundamental sensations we can find three such curves that a person of the first class will have some one of them, a person of the second class will have some two of them, and a person of the third class will have all three of them. This of course would be the simplest relation between the three classes. Such a relation was found to exist, but only after we disregarded the first class and the second (abnormal) division of the third class. But it is a remarkable circumstance that all persons of the first class so far known were found to have pathologically defective eyes. The case of the first (normal) subdivision of the third class we shall presently discuss. The result of those superpositions were the curve ®, G, and % in fig. 5. They all belong to the normal (the numerous) division of the ee thirdclass. The curves R and B are identical with the curves 8, and §, of the first, and the curves & and § with the curves YW, and &, of the second type of the second class, A much deeper in- sight into the nature of colour-sensations is obtained by examining cgi th a D Eb F G@ H more closely the case of the abnormal division of the third class. By the above-mentioned pro- cess of superposition we can get the two curves St and ¥, but instead of the middle curve G we get a transition form between #t and 6. Could we suppose that the first type of the second class is only a ON THOMAS YOUNG'S THEORY OF COLOUR-VISION. 437 special case of the third class, namely, a case in which the curve @ has so far altered its form as to coincide with St, then the abnormal division would be atransition form. Are there any facts in our experience that could lead us on to make such an assumption? Before answering this question I must call your kind attention to the following circumstance :— If we construct Newton’s colour-diagram (fig. 6), we find that the colours of the three fundamental sensations are :— For ¥, red (somewhat more purple than the colour of the long- waved end of the spectrum). For &, green (about the wave-length 505 py). For 8, blue (about the wave-length 470 py). Assuming now that the colour of the fundamental sensation of & remains the same, whereas the form of the curve is altered in such a manner as to coin- cide with Sf, it is Fig. 6. evident that the Green sensation belonging to this curve would be a resultant of the sensations belong- ing to ® and G,, that is, a yellow of about the wave- length 575 pp. I need hardly mention that co- lour-sensations are entirely subjective, and that in general the __colour-sensa- tions of two classes cannot be compared to each other. For- tunately Professors pa von Hippel and Holmgren have met with a young man who with respect to his right eye belonged to the first type of the second class, and with respect to his left eye belonged to the normal division of the third class. And this is the only person who can assist us in answering our question. His fundamental sensations for the first-mentioned eye were yellow and blue as compared to the sensations of the other, that is, the normal eye. This circumstance, therefore, justifies us in assuming that the first type of the second class is a special case of the third class. But whether the second type is also a special case of the third class future experience only will show. § 5. The following experiments will serve as an additional evidence that our results are correct. These experiments were made at my insti- gation by Mr. Brodhun, a student in our laboratory. Before entering upon the details of these experiments I must premise a few observations. According to our theory the colour at any part of the spectrum is determined by the ratio between the fundamental sensa- tions, whose resultant produces that colour. The change of this ratio White G, pq Blue 438 REPORT—1886. determines the rate at which the colour changes. A slight inspection of our fundamental curves shows that in the normal division of the third class there are two places in the spectrum at which the ratio of the fundamental sensations changes most rapidly, the one near the line D, the other near the line F, Now what is the simplest experimental method for determining the places in the spectrum at which the change of colour is the most rapid P If we take a light of known wave-length, and match it to a part of Fig. 7. a RG D Eb 6F G H another spectrum, simply by subjectively judging the colour, the difference in wave-length will give us the error of our judgment. Repeating this process with the same light at the same place a great number of times we shall obtain a mean error, which our judgment is apt to make in regard to this colour. It is evident that the smaller the change of colour at a given place of the spectrum the larger will be that mean error. This is the way in which Mr. Brodhun has determined experimentally the places in the spectrum at which the colour changes most rapidly. The curve A A A is the result of this sort of experimental investigation on a person of the third class. We see that the places of most rapid change of colour are about the lines D and F, and this agrees perfectly with what we have predicted from the inspection of our curves of fundamental sensation. The curve B BB, which was obtained in the same way from a person belonging to the second type of the second class, shows that there is one place of most rapid variation of colour, and this agrees perfectly with the inferences which we can draw from the inspection of the two curves of fundamental sensation for this type. P These are the principal features of our investigation on this subject. Its result seems to prove that the views of Thomas Young, slightly modified by modern experimental research, are perfectly correct. Thomas Young’s theory of colour-vision, one of the most beautiful twigs in his laurel crown, after lying as it were buried in the darkness of oblivion for more than half of a century, was brought to light again by Maxwell and Helmholtz, and, as we have seen, modern science seems ' EXPLICIT FORM OF THE COMPLETE CUBIC DIFFERENTIAL RESOLVENT. 439 to have breathed into it a life of such vigour that it will flourish for ever. On the Explicit Form of the Complete Cubic Differential Resolvent. By the Rev. Ropert Harey, F.R.S. [A communication ordered by the General Committee to be printed zm extenso among the Reports. } Tus paper is intended as supplementary to others relating to the theory of differential resolvents which I have had the honour to sub- mit to the Section at former meetings of the Association (see ‘ Reports,’ Transactions of Sections, 1862, pp. 4, 5; 1865, p. 6; 1866, pp. 2, 3; 1873, pp. 17-21; 1878, pp. 466-8). About four years ago Mr. Robert Rawson and myself calculated by independent methods the complete cubic differential resolvent ; in other words, we determined the explicit form of the linear differential equation of the second order which is satisfied by any root of the general algebraical equation (with unmodified coefficients) of the third degree. The result at which, after much labour, we both arrived has not hitherto been published ; and I desire now to place it on record, indicating at the same time some of the details of my own calculation. The process employed by Mr. Rawson may be elsewhere explained. Write the cubic equation in the form ay*® + 3by? + 3cy +d=0, and consider the coefficients a, b, c, d as functions of a single parameter, say «. Differentiate with respect to x, and denote the differentiations by accents ; then a slight reduction gives (a'b—al’) y?+ (a’c—ac') y+4(a'd—ad’) . a(ay?+2by +c) Integralise the function of y by any of the known methods, the result takes the form y= Ay/={(a'b—ab!)y?+ (al'e—ae!)y +4(a'd—ad')} (By?+Cy+D), A=a(a?d?—6abed + 4ac* + 4b3d—3b?c?) ; B=2a(ac—b?) ; C= —a?d+ 7abe—6b? ;sx D=—abd + 4ac? —3b?c. Develop the right-hand member and eliminate all powers of y higher than the second by means of the original cubic. We thus find oy’ =Ey?+Fy4+G. : : ; ; : . (1) where in which 0 =a?d?—6abed + 4ac? + 4b7d —3b7c?, the cubic discriminant; E=—acd | ia'—2abd | b'+ad | c' —2a%e | 4d’; + 462d + 2ac? —abe +2ab? —3bc? 440 REPORT—1886. F=—ad? | 4a'—acd b'+abd | c’+a?d | id’; + bed —22b7d +2ac? | —TZabe — 6c? +3be? —3b?c | +60 G= 2bd? | 4a’—ad? | b'+2acd| c'+abd | id’. —2c?7d + bed —2b2d —4Aac? | +30? Differentiate (1) and reduce. Then Dy" =Hy?+Iy4+Jd 3 ; : ‘ : : (2) in which H=o F/— o/b oR + SEF; a _ 6¢ I=o0 F/—o/F— —E’?+2HG+F?; a J=aG'—_'G— 24m + FG. a The elimination of y? between (1) and (2) gives 0 * Hy’ — o Hy’=(EI—FH)y,+EJ—GH P oi) (3) a result which admits of reduction, since both members contain the dis- criminant as a factor. For, EI—FH= 0 (EF —E’F) —=E (H(BcH—30F — a) +aF% ; EJ—GH= - (EG’—B’G) —=* (E(dE—30G) + FG}. Now E(8cH—3bF—aG)+aF?= - x ad? | ta'?—2abd | b!? + acc? + a® id’? —9bed +3ac? +93 +acd | 4a'b'—abd | 4a’e’—2a7d | ia/d'+a2d | d’e’ + 667d —6ac? +18abe —3abe —9bc? + 9b2¢ —18b3 —A4a’c | db'd'—2a7b(2c'd’). + 6ab? And E(dE—3bG)+aFG=0 x —2bd? ta’? + acd b/2+4- a@d | c+ a2b | We +3¢7d +ad? | 40/b'—4acd | a’ +abd ta'd' —2abd | b'c' —ted |! + 6b7d + 6ac? —9b?c | —a*d | 4b'd'—2a%e | ze'd’. +dabe i EXPLICIT FORM OF THE COMPLETE CUBIC DIFFERENTIAL RESOLVENT. 441 We have, therefore, the differential equation aa Hy!’—aHy'’+ [oE/F+E {(a?d?— + (a*ed + 2ab?d—3abe*)b" — — (a8d—7a*be+ bab?) 3d" a8 (5ad?— —a3(1d!) (4abd—6b?e)a’c! +3ac?b’?— (2a7c— Sab?) e!? — (2acd—1267d + 18be?)4a/b' — —(4a*d—36abe4+ 36b*)1a'd' + +2a7c(4b'd')} |y +al/G+E {—(2abd? + 2ac*d)3a” —(a?d®?—abedyb” + (2a?ed— + (a?bd—4a*c? + 3ab?c)3d"" + acdb'?—a*b(4d’") + (ad?—2bed) a! b’ = (10aed — 12b7d)4a'c' — Zabed + 6ac?)3a"' (a 2bd + 2a7c? — “Babee 18bcd + 18c?)ha + (2a7d—6abe)b'c! 2abd)c"’ — (4bd?—6e?d) 4a 12 (18abd—30ac? + 18b7c)h ad! —abdb'e' 4 (a2d—abe)b’ d' —(2a?c—3ab?)dc'd’} = =) the full development of which is an equation containing no fewer than 423 terms; namely, 4a'x b'x ex 3d’ -—aicd3 —2a‘bd* +ard3 —2a'cd* + 4a3b?d3 + 2a'c*d? —Ta'bed? + 2a'b?d? + 3a3be*d? +12a%h?cd? | +4a'c3d +12a'be*d 3 —4asetd —20a3bei'd + 4a3b3d? —8a'e* —28a*b3cd* | +8asc5 + 3a3b?e*d —20a3b%ed y+ +37a*b*e8d | —8a*bid? —4a%bc! + 14a3b7c8 —12a7bc° +14a*bc*d | —4a*b'cd + 8a°b'd + 16ab°d? — 6a7b*e* + 3a7b%c3 — 6a7b'c? —24ab'e7d + 9ab%c* 5 b"x ex 1d” x ia”? b? x ec? x +aicd* + 2a'bd$ —ards + 2a5ced* —2a°cd + 2a'd® —2a'bd? —4a3b*d3 =| —2a'‘c?d? +Ta'bed? \—2a'b?d? |+12a°b*d* |\—6a*bed? | + 6a'c*d —3a%be*d? |—12a%b?cd? |—4ate3d —12a'be*d |—6a*ctd + 2a%e8d — 6a3b*cd + 4a3e'd +20a3be?d |—4a3d3d* | +8a'c —64ab%cd? |—4a2b3d* | —2a%bc* + 28a*b8ed?| — 8a%c> —8a3bce7d | +20a%b3ed | + S8ab2e3d | + 12a7b?c?d| - 4a*b'd —37a*b*c8d | + 8a7b*d2 +4a%be —144a3b?c3 |—30abe> |—6a7be' +12a*be® |—14a7b3c?d |4+4a*b'ed |—8a7bd + 320d? —16ah>d? | + 6a?b*ec4 —3a7b3c3 | + 6a%b'c? |—48b1c?d + 24ab%e7d +180%c! —9ab c* 3d?x 4a'b! x da'c'x 4a'd'x bie’ x 1'd' x e'd’ x —2a*cd —20a%bd? | + 4a'd3 —2a'cd? |—6a'ed? |—4a'bd? | +2a°d? +2a'b’d = |+18a8e?d? |—12a*%bed? |+4a3b°d? | +12a%b?d? |+12a'ce*d |—16a'c* + 6a'be* + 84a°b*ed? |+4a%e8d = |—4a*b8ed |—12a7b3ed |—120%b*cd |— 4a°b8d —10a%b8e |—128a2be'd |—8a2b3d? | +2a7b%e? |4+6a2b%c? |—4a3de3 + 30a°b7c? + 4a?b> + 48a7e> + 24a7b*e%d +8a2b'd = |—12a7bte —32ab*d? —12a*be* + 48ab%c7d —18ab?c# 442 ; REPORT— 1886. 3a"b’ x Za"c! x tad’ x 1b"a' x b’e’ x 4b"d' tea! x — 2a%bd* +a'd3 — la'ed* + 2a5bd + acd? —2a'bd? |—a‘ds +3a%e7d* |—9a%bed? | + 2a3h?d? —3a%ed? |—6a%be*d | +12a%b*cd | + 9a%bed? + 1247b7cd*| + 4a3e3d + 6a%be*d —12a7b*cd*| + 4a3c* — 8a%be8 —4a3c%d —26a*be*'d | +4a*b3d? | —4a3e4 + 26a*be%d |\+4a7b8cd |—8a*b'd |—4a*b3d? + 12a? + 15a7b*e*d| —16a7b%cd —12a7c5 —3a7bc3 =| + 6a7b8c? | —15a*b?c*d —S8ab'd? |—12a7be* | + 114a7b%e3 + 8ab'd? +12a7be* +18ab%c*d |—12ab'cd | + 8abd —18ab%e7d + 12ab'ed —9abc3 + 9ab c3 —6ab'c? + 9ab*c4 —9ab3c3 cb! ke"d' x id’a' x id"b' x 3a"c' x g7t> x b5x — ated? + ard? +a%cd" + 2a'*hd? —ad* —2a*ed? + 2a3ced? +6a3bce*d = |—6a'bed | ~2a3p2d?2 —12a%b*cd \+6a'bed |+20ab7d? | + 4a*b2d —4asc* + 4a'e3 —6a%be7d + 8a%be3 —4a'c8 —18abe7d? |—12a*he*d —4a*bicd | + 4a3h3d + 4a! +8a7b'd |—4a3%i?d = |—72b8ed? | + 6a +3a°b?c? |—3a%b?c?_ | + 16a2b3ed —6a7b8e? | + 3a%b*c? | + 12667c8d —11a*h*c3 — 54dc° —8abed + 6ab'c? cS x ad? x 1a?b’ x 4a’c' x 3a?d' x 3b°a' x be! x —2a'ed + 2a°¢ —4a7bd3 +10a*bed? | + 2a°cd* + 2a8d3 —ba®bd? +2a567d = |—2a'b? + 40767d* —6a*e8d =|—8a*b?d? |—12a°bed? | + 12a7b*ed +12ab°ced? —l6ab3d? |—24a7be*d | + 2a*c8d —6a*be8 —l16abe*d —6abce*?d | +18a7ct — 28ab3d? + 6ac° +12abe* |+84ab ed | +72ab%e2d +166'd? +24b'cd = |—60ab7c? |—36abe' — 36)%e7d — 180%? —48b9d +18b%e' + 36b%c? 2d’ x ca’ x cb! x c?d'x 1d! x 4d’7b' x 4d¢' x —2a‘d* — 2a%bd* + 2a'd? + 2a'c? —2ated —2a'c? —2a‘be +12a%bcd |}+4a%c*d | + 2a3¢3 — 2a3b*c + 2a8h* + 6a%b*c + 2a%b3 —2a%c® —4a*b*ed |—4a73d +12a%be? |—4a7b' —8a*b8d — |—2a*be* —24a7b3¢ +4ab'd +12ab> a'b'e' x 3a'b'd' x da'c'd’ x U'e'd x —4Aa%cd* + 4a%bd? + 4a bed — 4a%be* +12a°b*d* | + 4a3c*d —12a%c* + 4a7b8¢ +4a*be*?d |—36a*b*cd |—4a7b*d —4a?c' +16a7bc3 | + 24a7b?c? —20ab%cd |+24ab'd |—12abte +12a6°c? |—12ab%c? Yr DP son FORM OF THE COMPLETE CUBIC DIFFERENTIAL RESOLVENT. 443 4a"b’ x 4a’’c' x 4al'd’ x 3b"a' x bc’ x 3b"d'x 40"a' x + aed? —2a®bd* + abcd” —a®cd* +a'd* —2a'‘ed? + 2a%bd —6a*be*d? | +12a*b*ced*| —6a*b*c*d | + 6a7be*d? |\—6abed? |+12a%be*d |—12a2bed? + 4a7etd —S8a*be'd | +4a7be —4a7c'd + 4aAed —8ar%ct + 8a7*beed +4ab%cd? |—8ab'd* +4abicd |—4ab%cd? |\+4a7b3d* |—8a*b3ed | + 8abtd? —3abed |\+6ab%c*d |—3ab 3 +3ab"e8d = |—3a*b?c?d |+6a2b2c3 |—6ab?e2d ex 4c"d' x 4da'x 3d"b'x zd%c' x aa’? x bx —a'd + abd? —a@bed? +2a'cd? |—a'bd? —2abed* | +2a%ds +6a%bed? |\—6a%b?ed | + 6a7b2c2d |—12a%be*d |+6a*b*ed |—16b3d3 — 4a*bed* —4a3c3d + 4a3bc8 —4a*be* + 8a%c* —4a%be% +360°c7d? | + 2a°e8d —4a*b3d2 |+4a°b'd |—4ab'ed |+8a*b8cd |—4a7b'd |—18bdc!d +3a7b°ce?d |—3a*b8c? | + 3ab%c3 —6a*b?c2 | +3a*b3c? cS x p,d®x 4a’b! 4a’c' x 1a?d' x ba’ x bc! x —2a@3bed = |+2a'be +8ab7d? |+2a°bd? |—4a*%bed? |—4a*bd? |—6aicd? +2a7b3d = |—2a3)3 —S8abe*d? |\—20ab*ed? |—8ab3d2 | +2a%e7d? | + 6a2b?d? + 2a0c'd +l4abe*d |+48ab2c7d | + 6ab*cd? =o —8b%ed? + 16b'd? —B0abce* |—4abe3d + 6b°e8d —120%e?d |—24b'ed + 186%? b'2d’ x ca! x 2b’ x cd’ x 1da' x 1b! x 4d’c! x —2a%bd? —2a°be*d | + 6a%c7d + 2a3be? +4a3bed |—2ated — 2a%b7e + 4a30*d +2abed |—6a*b*ed |—2a7b?c —4a*bd + 2a%h?*d + 2a*b* — 2a*be* —6a*b*c? | + 4a% be? + 6ab'e —4a76%e 3a'b'e’ x 4a'b'd’ x 4a'e'd’ x 4b'c'd' x — 2a3d* + 2a%cd* —2a3bd* + 2a‘d? + 36a*bed? | + 8a*b?d2 |+4a*b*ed |—16a%c? —20a*e8d =| —32a7be*d | + 4a*bc® —4a°bd —32ab3d? | +16a%c — 6ab%c? + 18a7b7c? + 18ab7c7d | + 12ab3ed —6ab?c* 444 REPORT—1886. On the Phenomena and Theories of Solution. By Professor W. A. TILDEN, F’.R.S. [A communication ordered by the General Committee to be printed in extenso among the Reports. ] In what follows I propose to review the principal phenomena ob- served in the act of solution of solids, and especially of metallic salts and other comparatively simple compounds in liquids, with the object of arriving, if possible, at some conclusion as to the physical explanation of the facts. For want of time and space an exhaustive statement of all that is known cannot be attempted. The most important parts of the subject omitted are the following :—LHlectrolysis, formule relating to expansion and density of solutions, their absorption-spectra, and other optical properties, and magnetic rotatory power. One question which must arise in the course of the discussion is whether the phenomena are to be accounted as chemical or physical, and this necessarily involves another question, namely, what is chemical combination, and by what criterion can it be distinguished from adhesion or cohesion, or other manifestation of molecular or molar attraction ? Postponing this enquiry for the present, we may assume that chemical combination has generally been supposed to be distinguished by definite proportions in weight and volume of the acting masses, by definite thermal changes, and by marked differences between the properties of the compound and those of its components. The various theories which have been proposed to explain the nature of solution are roughly divisible into two classes, namely, those which represent solution as a kind of chemical combination, and those which explain the phenomena by reference to the mechanical intermixture of molecules, or by the influence of the rival attractions of cohesion in the solid and liquid, and of adhesion of the solid to the liquid. The older writers seem universally to have regarded the act of solu- tion as a manifestation of chemical attraction. Thus Henry (‘ Elements of Chemistry,’ 11th ed., 1829, vol. i. Chap. II.) refers to the solution of common salt in water as ‘one of the simplest cases that can be adduced of the efficiency of chemical affinity, for solution is always the result of an affinity between the fluid and the solid which is acted upon, often feeble it is true, yet sufficient in force to overcome the cohesion of the solid. This affinity continues to act until at length a certain point is attained where the affinity of the solid and fluid for each other is balanced by the cohesion of the solid, and the solution cannot be carried further. This point is called saturation, and the fluid obtained is termed a saturated solution.’ Turner, in his ‘ Elements of Chemistry’ (1842), also attributes solution to ‘ the exercise of chemical attraction.’ Gay-Lussac (‘ Ann. Chim. Phys.’ xi. 297) states that ‘the solubility of a body in water depends on two causes, affinity and heat; or more exactly the affinity of salt for water varies with the temperature.’ Berthollet, in his ‘ Statique Chimique,’ gives an elaborate statement of his view, which is too long to quote in full, but the substance of which is to set forth the influence of affinity in bringing about solution ON THE PHENOMENA AND THEORIES OF SOLUTION. 445 and the resistance offered by gases in virtue of their elasticity and by solids in virtue of their cohesion. But Berthollet seems to have regarded chemical affinity as very closely connected with the cause of cohesion, if not identical with it. In the English translation by B. Lambert, 1804, to which alone I have had access, the following passages occur in the introduction, pp. xviii et seq. : ‘The first effect of affinity to which I call attention is that produced by the cohesion of the particles which enter into the composition of a body ; it is the effect of the reciprocal affinity of these particles which I dis- tinguish by the name of the force of cohesion, and ‘which becomes a force opposed to all those tending to cause them to enter into another combination, while it, on the contrary, tends to reunite them. ‘Every affinity which tends by its action to diminish the effect of cohesion ought to be regarded as a force opposed to it, and of which the result is solution. When, therefore, a liquid acts on a solid, the force of solution can produce the liquefaction of the solid if it is superior to that of cohesion; but this effect sometimes takes place immediately and sometimes it requires that the cohesion should be first weakened by a commencement of combination; there are circumstances in which the liquid can only act on the surface of the solid and wet it; finally the solid cannot even be wetted when its affinity with the liquid does not produce an effect greater than that of the mutual affinity of the parts of this latter. ‘These two forces, therefore, according to their relations produce different results, which must be distinguished, but which are not to be attributed, in conformity with the opinion of some philosophers, to two affinities, one of which they have considered as chemical and the other as derived from the laws of physics,’ &c. The same views with illustrative examples are expressed in Berthollet’s work on the ‘ Laws of Chemical Affinity.’ On page 63 of the English translation, by M. Farrell, 1804, we find this passage : ‘Solvents act on bodies which they dissolve by their affinity and quantity like all sub- stances which tend to combine ; and whatever has been said of combina- tion in general is applicable to them.’ ' It seems pretty clear, therefore, that Berthollet regarded solution as an act of chemical combination. He seems to have got some of his ideas from Guyton de Morveau, who some years before had published experi- ments on the adhesion of solids to liquids with the object of proving that ‘the adhesion of solids to liquids is in proportion to their affinity of solution.’! L. Gmelin (‘Handbook,’ vol. i. p. 112) summarises very clearly the _views prevailing up to his time: ‘Cohesion appears to exert a much more decided influence (than gravitation) on the decomposition of chemical compounds—at least of the less intimate kind. The hitherto received theory on this matter is as follows :—When a solid body dissolves in a liquid, the cohesion of the solid acts in opposition to the dissoiving power of the fluid; the two forces tend to equilibrate each other; and in pro- portion as the fluid takes up more and more of the solid, its tendency to dissolve a further quantity—or in other words, its affinity for the solid— diminishes, and ultimately becomes no greater than the cohesion of the 1 Footnote in Berthollet’s Chemical Affinity, English ed. p. 43; and Ann. Chim. Vii. p. 32. 446 REPORT—1886. solid and the tendency of its particles to remain united amongst them- selves, and then the process of solution stops. But the cohesion of a solid body is generally diminished by elevation of temperature; con- sequently when the fluid is heated up to a certain point a further solution usually takes place, till by this new addition of the solid body the affinity of the fiuid for it is so far diminished that equilibrium between that force, and the cohesion of the solid is again established. If now a solution thus saturated while warm be cooled down to its former temperature the solid body regains its original cohesive power, and a portion of it separates from the fluid in order to unite in larger and usually crystalline masses, the quantity remaining in solution,-being only just so much as the fluid would directly have taken up at this lower temperature.’ Among modern chemists we find Professor Josiah P. Cooke stating in his ‘ Chemical Philosophy’ (ed. 1882, p. 151) ‘ that the facts seem to justify the opinion that solution is in every case a chemical combination of the substances dissolved with the solvent, and that it differs from other examples of chemical change only in the weakness of the combining force.’ But the most consistent and powerful supporter of the hypothesis that in solutions the dissolved substance and the solvent are chemically combined together is M. Berthelot, whose views are expressed very clearly in his ‘Mécanique Chimique,’ from which the following is extracted (vol. ii. p. 160 et seq.) :-— ‘Les phénoménes de la dissolution normale sont en quelque sorte inter- médiaires entre le simple mélange et la combinaison véritable. En effet, d’une part l’aptitude 4 s’unir pour former un systeme homogéne indique une affinité réelle entre le solide et le dissolvant ; mais, d’autre part, cette union cesse sous l’influence d’une simple évaporation, et elle se produit, en apparence du moins, suivant des proportions qui varient d’une maniére continue avec la température. ‘Cependant il me parait probable que le point de départ de la dissolu- tion proprement dite réside dans la formation de certaines combinaisons définies entre le dissolvant et le corps dissous. Tels seraient les hydrates définis formés au sein de la liqueur méme, entre les sels et l’eau existant dans cette liqueur ; hydrates analogues ou identiques aux hydrates définis des mémes composants, connus sous | état cristallisé. ‘On est done conduit tout naturellement 4 se demander si ces hydrates ne subsisteraient pas jusque dans les dissolutions, et s'il ne s’en formerait pas d’analogues, dans les cas mémes ow l’on ne saurait pas les isoler par cristallisation. ‘Je pense en effet qu’il en est ainsi, et que chaque dissolution est réellement formée par le mélange d’une partie du dissolvant libre avec une partie du corps dissous, combinée au dissolvant suivant la loi des proportions définies. Tantdt cette combinaison se formerait intégrale- ment et d’une fagon exclusive, ce qui me parait étre sensiblement le cas pour les premiéres limites d’équilibre entre l’ean et les acides forts. Tantot, au contraire, cette combinaison ne se formerait qu’en partie, le tout constituant un systéme dissocié dans lequel le corps anhydre coexiste avec l’eau et son hydrate, ce qui me parait étre le cas pour les dissolutions formées par l’acétate de soude, le sulfate de soude et la plupart des sels alcalins. Plusieurs hydrates définis d’un méme corps dissous, les uns stables, les autres dissociés, peuvent exister 4 la fois au ON THE PHENOMENA AND THEORIES OF SOLUTION. 447 sein d’une dissolution. Is constituent alors un systéme en équilibre, dans lequel les proportions relatives de chaque hydrate varient avec la quantité d’eau, la température, ainsi qu’avec la présence des autres corps, acides, bases ou sels, capables de s’unir pour leur propre compte, soit 4 l’eau, soit au corps primitivement dissous. Ce serait le degré inégal de cette dissociation des hydrates, variable avec la tempéra- ture, qui ferait varier le coefficient de solubilité du corps dissous 1lui- méme.’ We may now turn to those writers who, whilst referring the phenomena of solution to a molecular attraction of some kind, do not attribute solubility to the formation of chemical compounds of definite composition. Graham is one writer who distinctly ranges himself on this side. He says :—‘ The attraction between salt and water which occasions the solution of the former, differs in several circumstances from the affinity which leads to the production of definite chemical compounds. In solution combination takes place in indefinite proportions, a certain quantity of common salt dissolving in or combining with any quantity of water, however large. . . . But the maximum proportion of salt dissolved or the saturating quantity has no relation to the atomic weight of the salt, and indeed varies exceedingly with the temperature of the solvent. The limit to the solubility of a salt seems to be immediately occasioned by its cohesion.’ And again: “The force which produces solution differs essentially from chemical affinity in being exerted be- tween analogous particles, in preference to particles which are very unlike and resembles more in this respect the attraction of cohesion.’ Brande, also, appears to have taken a similar view, for, although he makes no formal statement of his opinion, the following passage occurs in his ‘ Manual’ (5th edition, 1841), p. 110:—‘ When common salt is dissolved in water its particles may be regarded as disposed at regular distances throughout the fluid ; and if the quantity of water be consider- able, the particles will be too far asunder to exert reciprocal attraction ; in other words, they will be more powerfully attracted by the water than by each other.’ Daniell, in his ‘ Chemical Philosophy’ (1842), ascribes the phenomena of solution to the conflict between the ‘ heterogeneous adhesion ’ of liquid to solid and the ‘ homogeneous attraction’ of cohesion. In Miller’s ‘Chemistry,’ vol. i. (2nd edit. 1860), p. 67, we find the following passages, which show more in detail the application of ' the same idea :—‘ Adhesion is frequently manifested between solids and liquids with sufficient force to overcome the power of cohesion, and the substance is then said to become dissolved, or to undergo solution. . Anything that weakens the force of cohesion in the solid favours solution. Thus if the substance be powdered it becomes dissolved more quickly, both from the large extent of surface which it exposes and from the partial destruction of cohesion. In the same way heat, by increasing the distance between the particles of the solid, lessens its cohesion, and probably thus contributes so powerfully to assist in producing solution. If a solid body be introduced in successive portions into a quantity of a liquid capable of dissolving it, the first portions disappear rapidly, and as each succeeding quantity is added it is dissolved more slowly, until at length a point is reached at which it is no longer dissolved. When this occurs the force of cohesion balances that of adhesion, and the liquid is 448 REPORT—1886. said to be saturated. . . . Although in the majority of instances the solubility of a substance is increased by heat, it is not uniformly so. (Exceptions quoted: lime, sulphate and sucrate of lime, sulphate and seleniate of soda, &c.). These anomalous results may be partly explained by the consideration that heat diminishes the force of adhesion as well as that of cohesion ; generally speaking cohesion is the more rapidly diminished of the two, although not uniformly so, and in the cases of which we are now speaking it would appear that the adhesive force decreases in a greater ratio than the cohesion of the saline particles.’ The same idea forms the basis of the theory which has been supported so actively by the writings and experimental researches of Dr. W. W. J. Nicol (‘ Phil. Mag.’ Feb. 1883, &c.). Dr. Nicol’s view is stated in the following passage :-—‘ The solution of a salt in water is a consequence of the attraction of the molecules of water for a molecule of salt exceeding the attraction of the molecules of salt for one another. It follows, then, that as the number of dissolved salt molecules increases, the attraction of the dissimilar molecules is more and more balanced by the attraction of the similar molecules ; when these two forces are in equilibrium saturation takes place’ (Feb. 1883). L. Dossios has made use of the kinetic theory of Clausius relating to the constitution of bodies and the process of evaporation as the basis of a theory of solution. If we assume the kinetic energy of two neighbouring molecules to be less than their attraction, such molecules remain at a determinate distance from each other. Thisis the solid state. The gaseous condition is assumed when the kinetic energy of a molecule overcomes the combined attractions of the other molecules present. In a liquid the energy of two neighbouring molecules is sufficient to enable them to overcome each other’s attraction, but is not equal to the united attractions of the surrounding molecules. Relations of the same kind may be supposed to exist in an aggregation of dissimilar molecules such as compose a solution. Two liquids are miscible in all proportions when the attraction of dissimilar molecules is capable of overcoming the attraction of similar molecules, &c. The solution of solid bodies in liquids may be reduced to the same principles. As, however, the attraction of the molecules of solids to one another is large, and the kinetic energy destroyed, a solution of a solid cannot be formed in all proportions, but a point of saturation is attained, whilst the solubility of solid bodies increases generally with the tempera- ture, since the action of heat is always opposed to molecular attraction (‘ Jahresbericht,’ 1867, p. 92). A physical theory, which differs from those referred to above in not requiring the assumption of an attraction of either chemical or mechanical nature between the molecules of the solvent and those of the solvend, was briefly enunciated in a paper communicated to the Royal Society by Tilden and Shenstone in 1883. In discussing the connection between fusibility and solubility of salts, the authors point out that the facts tend to ‘support a kinetic theory of solution based on the mechanical theory of heat. The solution of a solid in a liquid would accordingly be analogous to the sublimation of such a solid into a gas, and proceeds from the intermixture of molecules detached from the solid with those of the surrounding liquid. Such a process is promoted by rise of tempera- ture, partly because the molecules of the still solid substance make longer ON THE PHENOMENA AND THEORIES OF SOLUTION. 449 excursions from their normal centre, partly because they are subjected to more violent encounter with the moving molecules of liquid’ (‘ Phil. Trans,’ i. 1884, p. 30). Such a theory, however, serves to account only for the initial stage in the process of solution, and does not explain the selective power of solvents nor the limitation of solvent power of a given liquid, &c. THERMAL PHENOMENA, How far is it true that evolution of heat indicates chemical com- bination? Does the evolution of heat in dissolving a solid in water or in adding more water to its solution indicate the formation of hydrates, that is, of chemical compounds of the dissolved substance with water in definite proportions? Thomsen answers this question in the negative (‘ Thermochem, Untersuchungen,’ iii, p. 20). Take the case of sulphuric anhydride, SO3. SO;,H,O = + 21320 (Solid SO, into liquid H,SO,) (SO,;H,0),H,0 = _—_ 6379 (No change of state) For next 2H,O average = 985°5 per H,O For next 4H,O average = AG. vere For next 10H,O average = 130°4-5,.. 5, _Up to 1599 HO total = 17857 The total heat of solution of SO; in 1600H,0 is therefore 21320 + 17857 = 39177. The following diagram (1) shows graphically the successive thermal changes consequent upon adding this quantity of water gradually to sulphuric anhydride. Although more than half the total heat evolution occurs on addition of the first molecule of water, the succeeding mole- cules give a quite appreciable amount; the second gives, in fact, sorts or nearly 3 of the whole. At what point in such a curve should we be justified in setting up a distinction between the effect due to chemical combination and that due to other causes ? In the act of solution of solids, and especially of anhydrous salts in water, the volume of solution is always less than the sum of the volumes of the solid and its solvent, with the exception of some ammonium salts, in which expansion occurs, Similarly the addition of water to a solu- tion is followed by contraction, This contraction may be due to mere mechanical fitting of the molecules of the one liquid into the interspaces between the molecules of the other, just as when one pint of small shot is mixed with one pint of large shot the volume of the mixture is less than two pints. This, I apprehend, would not by itself be attended by loss of energy (See Mendelejeff, ‘J. Russ. Chem. Soc.’ xvi. 643, 644. Abs. in ‘J. Chem, Soc.’ Feb. 1885, p. 114). Or it may arise from the adjustment of the motion of the molecules of the constituents to the ‘conditions requisite for the formation of a uniform liquid (Thomsen, iii. p. 18). If we know the coefficient of expansion of the liquid and its specific heat we can calculate the amount of heat that would be evolved for a 1886. GG ‘ 450 REPORT—1886. given contraction.! The contraction which ensues when H,S0O, is diluted with H,O amounts to 5°814 unit volumes upon 53'203+18, or 71-203, which is the sum of the molecular volumes of these liquids. And Fig. 1, 24 221/000 ja // 20|000 | [| Las 20 robook | | | | cust? [ot enw 7 8 oool| | Lee? aN a Ss CALORIES 2lo00 | U So tt g MOLECULES OF WATER taking the coefficient of expansion of H,SO,H,0 to be *00056 Gas fea, Ge and its specific heat 442, we find that this would correspond to an evolu tion of heat amounting to 45889 calories. The evolution of heat actually observed being 6379 according to Thomsen, there is a difference of 1790 heat units, which is unaccounted for on the hypothesis that the change of volume is due to just such a change in the mean distances and motions of the molecules of the liquid as would be brought about by a change of temperature, and this may really indicate some kind or some amount of chemical combination. The majority of solids, and nearly all salts, expand on being melted. And as, whatever theory we adopt as to the constitution of solutions, we must admit that the dissolved substance is in the liquid state, it is obvious that in all cases where a solid is dissolved by a liquid the change of volume which is observed must be the resultant of the two distinct changes of volume consequent upon the (1) liquefaction of the solid, and (2) the intermixture of the resulting liquid with the solvent. The diagram (fig. 1) already given exhibits the amount of contraction observed in the case of sulphuric acid and water, and the following table shows the observed and calculated molecular volumes by which the amount of contraction is indicated. 1 Favre & Valson, Compt. Rend. 1xxvii. ; Jahresb. 1872. ON THE PHENOMENA AND THEORIES OF SOLUTION. 451 C SC | Molecular Volumes of SO;+nH,O Contraction = Difference | n between Cale. and Density Mol. Vo. = Mol. Wt. observed Mol. Vol. Density 0 1:940 (Solid. Weber) 41:23 mi 1-842 53°20 6:03 2 1774 65°39 11°84 3 1652 81-11 14:12 4 1547 98°25 14:98 5 1:475 115-25 15°98 10 1:286 202718 19°05 The contraction consequent on the first addition is greater than the second, and for each succeeding molecule is a diminishing quantity, becoming rather less than 1 after addition of 3H,0. A similar result ensues if we calculate the contraction following upon the dilution of liquid H,SO, with successive quantities of water. Take now another case, that of common salt (see diagram 2). The heat of solution of NaCl in 100H,O is—1180, a negative quan- tity. On adding more water to a solution of sodium chloride a further absorption of heat is observed. Thomsen gives the following values :— (NaCl 10H,0) + 40H,O=— 528; (NaC150H,O) + 50H,O=—127; (NaC1100H,O) +100H,O=— 50. So that heat of solution of NaCl in 10H,O = — (1180 — 655) = — 525; 50H,O = — (1180 —127)= — 1053 ; 200H,O = — (1180 + 50) = — 1280. Tracing now the changes of volume which attend the processes of solution and dilution we get the following results :— Taking 2°15 as the density of the solid salt we have its molecular volume = 27:1. Then the following are the molecular volumes of its solutions :— nH,0 Molecular Volume Contraction Calculated Observed ! n=10 20771 200°9 5:2 n=50 927-1 91871 9:0 n=100 1827°1 1817°5 9°6 Another way of stating these results would be to set down the thermal and volume changes resulting from the addition of successive molecular proportions of salt to the same amount of water. From the foregoing results we find— Difference per Molecule NaCl+100H,O = — 1180 C. — 2NaC1+100H,O = — 2106 C. 926 ; 10NaCl1+100H,O = — 5256 C. 18393. So that whilst the addition either of salt or of water to a solution of salt occasions an absorption of heat, the solution of a molecule of solid sodium chloride in a relatively large quantity of water is attended by the absorp- ’ Nicol, Phil. Mag. June 1884. GG 2 452 REPORT—1886. tion of a much greater amount of heat than the solution of the same quantity of the solid in a relatively small mass of water. In like manner it is observed that the addition of water or of salt to a solution already formed occasions contraction, but the amount of this Fie. 2. MOLECULES OF WATER 10. 20 30 40 50 n a) = > a r) S & 2 3 CALORIES contraction constantly diminishes with each successive dose of water or of solid salt. This has just been shown for the water. The following table, taken from Nicol’s paper (‘ Phil. Mag.,’ June 1884),! shows the effect of adding salt in successive molecules. The column headed A shows that the molecular volume of each successive molecule is greater than the preceding, the increase being from 17:08 up to 22°87 for the last molecule. nNaCl-+ 100H,0 t° n M.V. A oO 20 5 180854 17:08 1:0 1817°60 17°60 : 2-0 1836°42 18:82 7 30 | 185613 19-71 nt 4-0 1876-74 20°61 Ee 5-0 1897-79 | 21-05 a 6:0 | 191944 21°65 7-0 1941°54 | 22-10 - 8-0 1963-93 22-39 x 9-0 1986°72 22:79 K 10:0 2009-65 | 22-93 if 11:0 2032-52 | 22:87 1 The figures given in the table are the result of recent more accurate determina- tions, kindly communicated by the author. ON THE PHENOMENA AND THEORIES OF SOLUTION. 453 In this case, common salt, we find in accordance with the general rule (Thomsen, iii. p. 28 et seq.) that the heat of dissolution being negative the heat of dilution is also negative. Supposing we explain the heat- absorption which attends the act of solution by referring to the change of the solid salt to liquid it still remains to be considered to what cause we can ascribe the heat-absorption attending dilution when liquid is mixed with liquid and no change of state is involved. There is contraction upon adding water to a solution of common salt, but this, if it is connected with any thermal change at all, would probably lead to an evolution of heat. It has just been shown that the thermal change attending solution of salt in water cannot be due solely to the change of state from solid to liquid. If it were, the same amount of heat-absorption would be observed in dissolving salt in any proportion of water, and no change would be produced by adding more water. There is therefore apparently some agency which gives a positive thermal change on solution of the solid, and another which occasions a negative change on the dilution with more water, the observed amounts of heat absorbed being the difference be- tween these two. The positive thermal change probably corresponds to some kind of union between the salt molecules and the water. The negative thermal change is chiefly connected in the act of solution with the physical change from solid to liquid. The negative change consequent on dilution is not so easily accounted for. But it may be due to double decomposition with the water. The reaction NaHO + HCl = NaCl + H,O is attended with heat-evolution, and its reversal NaCl + H,O = NaHO + HCl must lead to heat-absorption. From Thomsen’s results NaHO + HCl + 200H,O = + 13745, and NaCl + 10H,O = — 525, and : (NaCil0H,O) + 190H,0 = — (1230 — 525) = — 705. So that for complete decomposition we should require — 13745 cal., whilst in diluting a solution almost saturated down to a very weak con- 705 ition, the h 1 i 13745 + 705 dition, the hypothesis does not require more than 13745 + 708 , or alittle more than five per cent. of the whole. My own experiments on heat of dissolution of salts at different temperatures (‘ Proc. R. 8.’ 1885) led me to the conclusion that decom- position of this kind did occur, and that it increases with rise of temperature. Thomsen, on the other hand (iii. p. 20), considers that his results do not point to a decomposition in such cases as common salt ; but he admits it in-the case of bisulphates of sodium and potassium. As a rule, a salt which on being dissolved in water gives out heat gives a further amount when its solution is diluted. On the other hand, a salt which in dissolving absorbs heat absorbs a further amount when its solution is diluted. Of thirty-five salts examined by Thomsen, twenty- 454. REPORT—1886. nine conform to this rule. The exceptions most difficult to explain are sodium sulphate and carbonate, both of which exhibit anomalies in their solubility. However we may ultimately explain the peculiarities of these two salts, the fact remains that heat evolved or absorbed during the admixture of any substance with water is in every case a continuous function of the quantity of water added, and a thermal change gradually diminishing in amount is observed on the addition of successive quantities of water, till an indefinitely large volume has been added, and the change becomes too small to be traced by the thermometer. | Similarly the contraction which ensues on diluting an aqueous solution proceeds continuously, and, as already shown, the molecular volume of a salt in solutions of different strengths is continuously greater the larger the amount of salt present, so that in none of these thermal or volumetric phenomena is any discontinuity observed nor any indications of the formation of compounds of definite composition dis- tinguishable by characteristic properties. If, however, we admit that no definite chemical compounds are formed in such a case as the admixture of sulphuric acid H,SO, with water, what are we to say to the parallel case of the neutralisation of some polybasic acids with alkali P Take orthophosphoric acid. Difference per Molecule of NaHO. H,PO,Aq+3NaHOAq=+ 7329 C. +1NaHOAq = + 14829 4+2NaHOAq = + 27078 12249 4+3NaHOAq = + 34029 6951 4+6NaHOAg = + 35280 1251417, The addition of The first mol. H,O to H,SO, gives + 6379 The second mol. H,O to the preceding mixture + 3039 The third mol. H,O to the preceding mixture + 1719 So the addition of The first mol. of NaHO to H;PO, gives + 14829 The second mol. of NaHO to the preceding mixture + 12249 The third mol. of NaHO to the preceding mixture + 6951 Arsenic acid gives similar results, the several values being in each case a little higher than those obtained with phosphoric acid (Thomsen, i. 204). The case of periodic acid (Thomsen, i. 244) is still more noteworthy. H,10,Aq+ KHOAq =+5150 ©. 4+2KHOAq = 26590 43KHOAq = 29740 45KHOAq = 32040 Here we have great inequality in the amount of heat evolved on addition of successive molecules of alkali and no sign of approaching a maximum. These values are indicated on the accompanying diagram (fig. 3) :— In the case of sulphuric acid, neutralisation by soda shows a more Pa ON THE PHENOMENA AND THEORIES OF SOLUTION. 455 nearly equal amount of heat evolved per molecule of NaHO added. Thomsen gives (i. p. 297)— NaHOAg + H.SO,Aq = + 14754 2NaHOAg + H, SO,Aq = + 31378 4NaHOAgq + H,SO, Aq = + 31368 Difference 16624: The second molecule of NaHO therefore seems to give more heat than the first. In the case of acids and alkalies we do not hesitate to accept such results as indicating the formation of definite chemical compounds, and that they do correspond with the known basicity of the majority of the acids there can be no doubt. But there are very few cases in which the thermal value of the action of the second or third molecule of alkali is exactly equal to that of the first. There can be little doubt that in every one of these cases of dilution and of neutralisation the observed thermal effect is due partly to chemi- cal combinations, partly to changes which are commonly distinguished as physical.! Fig. 3. Speciric Heats AND VAPOUR PRESSURES. The question we are now con- sidering as to whether in a solution the solvent and the substance dis- solved in it or any portion thereof exist independently of each other is in some degree answered by the facts known as to the specific heats and 5A 0,Aq + |nNaHO ag vapour pressures. In the case of Ms ray ie tn a salts dissolved in water the value of the molecular heat (that is, the pro- duct of the specific heat into mole- cular weight) in moderateiy dilute solutions differs very little from that h | | | |_| of the water alone contained in the P| | solution. In strong solutions of salts I (5 to 20 mols. of water to 1 mol. 1 MOL: ®ACID + NMOLS:ALKAL! salt) it is sometimes greater, some- —— [| times less than that of the water alone. In weaker solutions (50 to 200 molecules water) it is generally less than the water alone. For example :— » = s x = c = k 1 Vide Correlation of Physical Properties of Solution nith Concentration —Mende- lejeff, Ber. xix. 370 and 400, discusses the relations of contraction and thermal change. 456 REPORT— 1886. NaCl+nH,0 n Spec. Heat Mol. Weight Molec. Heat Difference from water alone’ 10 Cra 58°5 + 180 188°5 +85 20 863 58°5 + 360 361°9 +10 30 895 58°5 + 540 536°0 —40 50 931 58°5 + 900 892-0 —80 100 “962 58°5 + 1800 1788°0 —12:0 200 ‘978 58°5 + 3600 3578°0 — 22:0 (Thomsen, i. 48.) The specific heat of substances in the liquid state is always greater than that of the same in the solid, but the difference is in no case of those recorded so great as the difference between water and ice [except such things as chloral hydrate, in which water may be supposed to be formed during fusion, and the solitary case of iodine, solid ‘05412 (Regnault) and liquid ‘10822 (Favre and Silbermann)]. The specific heat of solid sodium nitrate is ‘278 (Regnault, ‘ Ann. Chim. Phys.’ 1841, i. 179), and in the liquid state it is ‘413 (Person, ‘ Ann. Chim. Phys.’ 1847, xxi. 332). Hence the molecular heats are— Solid 23°63 Liquid 35:10 If we assume the latter for the solution we have NaNO, 35°10 25H,0 450°00 485°10 The observed molecular heat of the solution NaNO,+25H,O is 465°5 (Marignac), or 461°7 (Thomsen). Now suppose 45H,0 more water to be added, the molecular heat is not 465°5+450=915'5, but 908 (Marignac), or 904 (Thomsen). And again when 50 more molecules of water are added the molecular heat is not 908+900=1808, but 180225 (Marignac), or 1791 (Thomsen), and so on. So that all the water added seems to be influenced, at least until a very large quantity is present. In this case one molecule of sodium nitrate can affect the movements of 100 molecules of water, and prob- ably more. This effect is doubtless connected with the changes of volume which the solution undergoes on dilution. Marignac has given the results of the determination of the specific heats of a number of salt solutions at different temperatures, but though it may be stated, as generally true, that the specific heat of a solution increases with rise of temperature, the differences observed are too small to afford much ground for speculation. They are generally much less than the increase in the specific heat of water for the same range of temperature, namely, from about 18° to 20° and from 20° to 50°, taking even the lowest value which has been assigned by different authorities to ON THE PHENOMENA AND THEORIES OF SOLUTION. A457 the increase in the specific heat of water at this higher temperature. (For numerical values see Naumann, ‘Thermochemie,’ pp. 269—271.) It is also well known that the vapour pressure of water holding in solution almost any dissolved solid is less than the vapour pressure of pure water, and that the boiling point of a liquid is raised by the addition to it of any soluble non-volatile substance. The well-known researches of Willner (Pogg. ‘ Ann.’ ciii. p. 529, and ex. p. 564) led him to the conclusion that the reduction in the tension of the vapour of water consequent upon the addition of soluble substances is proportional to the amount of dissolved substance (see, however, Nicol, ‘ Phil. Mag.’ Oct. 1885). The law connecting the amount of dissolved substance with the diminution of pressure, or the amount of diminution with the tempera- ture, is, however, a matter of small importance in connection with the present inquiry. The fact that there is reduction of pressure is the important point, and this can only be explained upon the hypothesis that there is no free water present at all; that is, that there is no water present which is not more or less under the influence of the dissolved substance. If any water were present in an uncombined state the rate of evaporation from the surface would doubtless be slower than the rate of evaporation of pure water at the same temperature, but the pressure of the evolved vapour must in time attain to the same maximum.. WATER OF CRYSTALLISATION. What becomes of water of crystallisation forms a part of the same question as to the relation of solvent to solvend. We know that when white copper sulphate is dissolved in water evolution of heat results, and a blue solution is formed of the same colour as the crystals of the hydrated salt and the solution formed by dissolving them in water. Similarly blue anhydrous cobalt chloride dissolves in water, forming a red solution of the same tint as the red crystals which contain the salt and water united together. We are, therefore, disposed to conclude that these salts, and by analogy those which are colourless, retain their hold upon the water of crystallisation when they are dissolved in water. Thomsen has also shown ! that of thethirty-five salts examined by him twenty-nine exhibit the peculiarity that when the anhydrous salt dissolves in water with evolution of heat, the addition of more water also causes evolution of heat, and that when, on the contrary, the heat of solution is negative, the heat of dilution is also negative, The former without exception unite with water to form crystallisable definite hydrates; the latter do not. Thomsen states his opinion on the point thus (iii. p. 31) :—‘ There is no doubt that the salts which dissolve in water with evolution of much heat, and form crystallised hydrates, are present also in the solution as hydrated compounds; but a determination of the number of water mole- cules contained in such compounds would be very difficult,’ &c. Thomsen considers the hypothesis very probable that a salt dissolved in water cannot retain chemically combined a larger number of water molecules than are 1 THOMSEN’S Two GroupPs.—I. Chlorides, Ca, Mg, Zn, Ni, Cu; nitrates, Mg, Mn, Zn, Cu; acetates, K, Na, Am, Zn; sulphates, Mg, Mn, Zn, Cu, and NaHSO,. Il. Chlorides, Na, Am; bromide, K; cyanide, K; sulphate, Am; nitrates, Na, Am, Sr, Pb; tartrate, Am; and bicarbonate, Am. Exceptions: KHSO,, AmHSO,, Nal, K,CO,, Na,CO,, Na,S0O,. 458 REPORT—1886. already combined in the acid and base from which the salt may be pro- duced. Thomsen also considers that the chemical constitution of the hydrates present in a solution is not altered by dilution of the liquid with more water. But against these facts above stated we find that salts which are very soluble, and which crystallise with a large amount of water, such as calcium chloride, do not, as a rule, reduce the pressure of vapour of water in which they are dissolved to a greater extent than salts which, like sodium chloride and potassium nitrate, crystallise habitually without water. There can be no doubt that every one of these and similar thermal effects are, like the corresponding volume changes, merely differential results, which represent the resultant of several simultaneous or im- mediately consecutive operations. A very important observation has been made by Dr. Nicol, which bears directly on this question. In his study of the molecular volumes of salt solutions (‘ Phil. Mag.’ Sept. 1884) he finds that when a salt containing water of crystallisation is dissolved this water is indistinguish- able by its volume from the rest of the water of the solution. In the Report! presented to the British Association last year the following passage occurs :—‘ These results point to the presence in solution of what may be termed the anhydrous salt, in contradistinction to the view that a hydrate, definite or indefinite, results from solution ; or in other words, no part of the water in solution is in a position, relatively to the salt, different from the remainder.’ These two statements are not strictly consequent upon each other. I feel inclined to take the view that, save perhaps in excessively dilute solutions, the dissolved substance is attached in some mysterious way (it Fie. 4. [MOLECULAR VOLUME OF n*MOL: OF Hi20 IN SOLID SULPHATES OF MAGNESIUM GROUP (THORPE w WATTS) | {MOLECULES _ | matters not whether it is supposed to be chemical or physical) to the whole of the water. We cannot otherwise get over the difficulties presented by the bydrated salts which give coloured solutions, by the control of mes vapour pressure by the dissolved salt, and by the altered specific eat. With regard to water of crystallisation, E. Wiedemann (‘ Wiedem. Ann.’ xvii. 1882, p. 561), has shown that hydrated salts in general expand 1 Report of Committee on Vapour Pressures, &c., of Salt Solutions, Dr. W. W. J- Nicol, secretary. Presented at Aberdeen Meeting. ON THE PHENOMENA AND THEORIES OF SOLUTION. 459 enormously at the melting point, and sometimes at lower temperatures, and the observations of Thorpe and Watts (‘Chem. Soc. Journ.’ 1880, p- 102) on the specific volume of water of crystallisation in the sulphates of the so-called magnesium group show that, whilst the constitutional water, or water of halhydration, as it was called by Graham, occupies less space than the remaining molecules, each successive additional molecule occupies a gradually increasing volume. The following are mean specific volumes of MSO,nH,0, where M is Cu, Mg, Zn, Ni, Co, Mn, or Fe. Value of Mean Specific Molecular Volume n Volume of nth mol. of H,O 0 448 1 555 10°7 2 68°8 13°3 3 83:3 14:5 4 98°7 15°4 5 1129 14:2 6 130-0 abyeal 7 146.1 16:1 These last figures approach the specific volume of ice, which is he =19°6, that of water being 18. v2 So that, when a salt with its water of crystallisation passes into the liquid state, either by melting or solution in water, it requires a very slight relaxation of the bonds which hold the water to the salt for it to acquire the full volume of liquid water, whilst the water of constitution is not so easily released. And this conclusion accords with Nicol’s observations on the molecular volumes of the salts when in solution. CuEmicaL ConstituTion.—F usibinity.—MoLEcuLtaR VOLUME IN RELATION to SOLUBILITY. And now comes the question as to what determines the solubility of a substance. Why, for example, is magnesium sulphate very soluble in water whilst barium sulphate is almost totally insoluble ? With regard to salts the following propositions seem to be true :— 1. Nearly all salts which contain water of crystallisation are soluble in water, and for the most part they are easily soluble, calcium sulphate: being one of the least soluble, magnesium phosphates and arsenates and some natural silicates (zeolites) being also exceptions. 2. Insoluble salts are almost always destitute of water of crystallisa- tion, and rarely contain the elements of water. 3. In a series of salts containing nearly allied metals the solubility and capacity for uniting with water of crystallisation generally diminish as the atomic weight increases, as in the following examples :— ear K,SO, (Na,CrO,10H,O (K,CrO, 460 REPORT— 1886. MgSO,7H,O CaSO,2H,O SrSO, BaSO, CaCl,6H,O Mg(NO3),6H,O SrCl,6H,O Ca(NO;).6H,O BaCl,2H,O Sr(NO;),4H,O PbCl, or anhydrous from hot solution. Ba(NO3)> Pb(NOs)s In the preceding examples disposition to combine with water seems to depend more on the nature of the basic radicle than on the acid radicle of the salt. On the other hand we have NaCl NaNO, ; but Na,00,10H,0 Na,SO,10H,O Na,HPO, 12H,0, &e. The fusibility of a substance has much to do with its solubility. This has been pointed out by Carnelley (‘ Phil, Mag.’ March 1882) in reference to carbon compounds, and by myself and Mr. Shenstone (‘ Phil. Trans.,’ 1884, and ‘ Jour. Chem. Soc.’ July 1884) in reference to salts. _ Neither fusibility alone nor chemical constitution alone seems to be sufficient to determine whether a solid shall be soluble or not; but it may be taken as a rule to which there are no exceptions that when there is close connection in chemical constitution between a liquid and solid, and the solid is at the same time easily fusible, it will also be easily soluble in that liquid.! I take it that a salt containing water of crystallisation may be con- sidered as closely resembling water itself. For example— MgSO,7H,0 may be considered as a congeries of eight molecules of water, H,O7H,O, in which one molecule of water is replaced by the elements of the salt. We know that exchange of a similar kind is possible in the case of water of halhydration, as long ago pointed out by Graham. MgSO,H,06H,0 (giving MgSO,K,S0,6H,0, &e. — So that MgSO,7H,O being like solid water in constitution, and also easily fusible by heat (it melts at 70°), it is easily soluble in water, and the solubility increases rapidly with rise of temperature. The effect of fusibility on increase of solubility with rise of tempera- ture is well shown by comparison of two such salts as Potassium chlorate. : . m.p. 359° Potassium chloride. : . map. 734° both of which are destitute of water, and are therefore comparable (see fig. 5, p. 46). ” There are many substances which contain much water—or the elements of water—which, nevertheless, do not dissolve in water, or dissolve with 1 This, of course, does not explain how it is that, although silver chloride is insoluble in water, the less fusible sodium chloride is easily soluble. ON THE PHENOMENA AND THEORIES OF SOLUTION. 461 difficulty. Such are the hydrated oxides or hydroxides of the metals; but these are generally infusible :— Al,03.3H,O Fe,03.3H,0 Cr,03.3H,0 } infusible, very slightly soluble. Mg0O.H,O Ca0.H,O Those which are easily fusible are also easily soluble, as the following :— BaO2H,08H,0 m.p. 100° Sr02H,08H,O0 mp. ? K,0H,O Na,OH,O I take such examples as these as affording an argument for the hypo- thesis that such compounds retain their water when they pass into solu- Fig. 5. y i=} 4 ft hal & ly E $ u 9 wy K c sv a b= 2 i= ~ >s Ga w io) 7) K c x a TEMP O° tion, else how can we account for the immense difference of solubility between baryta and strontia on the one hand, and lime and magnesia on the other ? Take the converse of easy fusibility associated with no connection of composition between solvent and solid, or in a series a diminishing con- nection. ; The lower terms of the various series of alcohols and acids show con- siderable similarity to water in their general behaviour, the higher terms 462 REPORT—1 886. much less. The lower terms may, in fact, be regarded fairly as formed on the same type as water :— CHa, cae alo, Usel ote. But when the hydrocarbon radicle becomes very large and complicated it is much nearer the truth to say that the resulting substances are formed on the type of hydrocarbons, in which H is replaced by the water residue, the latter forming so small a portion of the whole that it fails to impress on the compound its own characteristics. We have, then, among the alcohols— ed resembling water and miscible with water CH HO} in all proportions. C,H,HO C.H..HO, & not miscible in all proportions. oo 1h ’ . CO, -Uz00 ip. 50°) fusible, waxy solids, insoluble in water, but soluble Gj-H,,HO ~m.p. 97° in ether and hydrocarbons, resembling the hy- C3,H,,HO mp. 85°} drocarbon C,,H3,; m.p. 21°. Again— Solubility in Water. Benzene . . (©,H,H insoluble, though fusible. Phenol . . ©,H;OH slightly soluble. Catechol . | Quinol . . }C,H,(OH), easily soluble. Resorcinol . Pyrogallol . C,H,(OH), still more soluble. And— Order of Solubility in Water. Phenol . pA Ono. pial: ] All easily soluble in alcohol, Naphthols 2) 1G; HOH. - 2 - ether, and especially ben- Anthrols . « OC),H,OH . .s J zene, Dr. Carnelley has taken up the question of the relation between atomic constitution and solubility from a different point of view, and he has shown by reference to many examples, drawn chiefly, though not exclusively, from the aromatic division of carbon compounds, that of two isomeric compounds the one which has the less symmetrical constitution has the lower melting-point and the greater solubility (‘ Phil. Mag.’ February and March 1882). Kremers in 1854 and 1855 attempted a discussion of the relations between the constitution of salts and their solubility (‘ Pogg. Ann.’ xcii. 497, and xciv. 87 and 255). He seems to have arrived at no very definite conclusions. One thing which he attempted to do was to trace the con- nection between atomic (molecular) volume and solubility, and he would probably have been more successful if he had had the advantage of a uniform and consistent system of atomic weights. As it was, he arrived at the conclusion (‘ Pogg.’ xciv. p. 90) that ‘greater atomic volume is associated sometimes with greater solubility, sometimes with less.’ This part of the subject has been taken up more successfully by Dr. Nicol (‘ Phil. Mag* June 1884, January 1886), and he has shown that the molecular volume of certain salts is larger in strong solutions than in ON THE PHENOMENA AND THEORIES OF SOLUTION. 463 weak ones, and that in the cases examined the solubility is greater the more nearly the molecular volume in a saturated solution ap- proaches the molecular volume of the salt in the solid state. But it has not, so far as I know, been shown that the molecular volume in the solid state determines the degree of solubility of the salt. Thus the molecular volume of KCI solid is 37:4, and the molecular volume of NaCl solid is 27-1. But sodium chloride is more soluble at temperatures below about 25° than potassium chloride, and silver chloride, which is insoluble, has a molecular volume, 25°8, scarcely less than that of sodium chloride. Similarly, the molecular volume of KNO, (solid) is 48°7, and that of NaNO,, 37°9, but the latter is more soluble than the former. Molecular volume is dependent— (1) On the atomic weights of the elements present. (2) On the constitution of the substance, that is, on the manner in which the constituent atoms are united together. (3) On the density of the substance. It has been already shown that in many cases increase of molecular weight corresponds to diminished solubility. In the equation Mol. vol, = Mol. weight Density the value of molecular volume is greater in proportion as molecular weight is greater, but also in proportion as density is less It is the latter which seems to correspond to increased solubility. (4) Molecular volume is also probably connected with fusibility and perhaps with hardness as distinguished from density.! But neither molecular volume nor fusibility is sufficient to determine the degree of solubility of a solid. There must be another element in the question which may be, and probably is, attraction or affinity—what- ever that may mean—between the substance and the solvent. This is shown by such a case as the nitrates of potassium, sodium, and silver :— SoLuBILITY Melting Parts of Salt in Molecules in 100 Molecular Volume Paint 100 parts of Water} mols. of Water at 0° | at100°| ato? | at 100° KNO, 07 = 48-7 339° 13°3 265 2°36 | 47-3 85 NaNO, 204 = 379 316° 72-9 180 1543 | 38-1 1 AgNO, soins = 39°] 217° 121:9 830 12-9 | 87-9 * The mineralogists’ ordinary scale of hardness, with the exception of tale, re- presents a rough scale of solubility :—1, tale; 2, rock salt; 3, cale spar; 4, fluor; 5, apatite ; 6, felspar; 7, quartz; §, topaz; 9, sapphire; 10, diamond. 464 REPORT—1886. Surrace Acrion or Soups. The absorption and condensation of gases upon solid surfaces, and more especially in porous substances, is well known. The action of the same substances upon liquids has not been studied to the same extent, but some facts are known which bear upon the question under discussion. Graham, in 1830, published (‘Pogg.’ xix. 139) some experiments by which he showed that animal charcoal, purified by acids, and containing only a small quantity of silica, was capable of removing, from solution in water, not only colouring matters, a fact long previously known, but various metallic salts. Common salt was not precipitated, but solutions of nitrate of lead, acetate of lead, tartar emetic, ammonia-sulphate of copper, were completely deprived of their metal. In some cases the salt was taken up again when heat was applied. In some other cases, as solution of silver nitrate in ammonia and lead oxide in caustic potash, the metal was more or less reduced, being first precipitated as oxide. The quantity of lead oxide precipitated was so great as to be recognisable by its white colour in the charcoal. In 1845 Warrington (‘ Phil. Mag.,’ xxvii. 269) drew attention to the power possessed by charcoal of removing bitter substances and alkaloids from aqueous solutions. Many other solid substances, when in a state of fine subdivision, exert a similar action. Precipitated sulphide of lead, oxide of iron, alumina, clay, &c., possess this power as well as platinum in the state of sponge or deposited upon asbestos (Stenhouse). Cotton immersed in solution of alum was observed many years ago by Chevreul to be capable of withdrawing a liquid containing less alum than the original solution, and it has long been known to possess the power of abstracting oxide of lead, tannin, and various soluble colouring matters from their respective solutions (see Crum on the manner in which cotton combines with colouring matter, ‘Phil. Mag.’ April 1844; and ‘J. Chem. Soc.’ 1862). Other porous insoluble substances are said to possess similar powers. Thus sand is said to be capable of removing acetic acid from the first portions of vinegar filtered through it (Gmelin, i. 114), and similarly to remove salt from sea-water (‘ Ure’s Dict.’ 1878, Art. Water, Sea). I confess to have tried this experiment without success, Solutions of common salt, and of alum of different strengths, were filtered through about twelve feet of dry white sand. The first portions of liquid running through were collected separately, but the quantity of salt present was not appreciably less than in the original solution. However, it is probable that by varying the form of the experiment the result might have been somewhat different. J. Thoulet (‘ Compt. Rend.’ xcix. 1072, c. 1002) finds that the attraction between the surface of a solid and a dissolved salt can be observed when marble, kaolin, or quartz is immersed in solutions of sodium or barium chloride, and that the action is proportional to the surface of the dissolved solid. The action of filter paper upon saline solutions has been examined by Mr. Bayley (‘ Jour. Chem. Soc.’ 1878). When a drop of a solution of a metallic salt is placed upon filter paper, the water spreads away into the paper, leaving a more concentrated solution in the centre of the spot. A great difference is, however, observed in the behaviour of the salts of various metals. Silver, lead, and mercuric salts give a wide water ring, ON THE PHENOMENA AND THEORIES OF SOLUTION. 465 as also do solutions of copper, nickel, and cobalt when dilute. But cad- minum salts differ from all the rest in spreading to the edge of the blot. The water ring was widest when dilute solutions were used. Mr. Bayley’s results have been confirmed and extended by J. U. Lloyd (‘ Chem. News,’ li. 5]-54). Other porous substances, such as unglazed earthenware, behave in a similar manner, and are even capable of depriving salts of water of crystallisation, as observed by Potilitzin in the case of cobalt chloride (‘ Ber.’ xvii. 276). All these facts are undoubtedly connected, not only with the ascent of liquids in tubes, but with the property which very finely divided, though insoluble, powders generally possess of showing a rise of tempera- ture! when wetted, and of remaining suspended in a liquid in a state which is sometimes referred to as pseudo-solution, until small quantities of certain soluble matters are added ; that is to say, in every case there is adhesion or surface attraction manifested between the solid and the liquid, which is greater in proportion as the particles of the solid are smaller and expose a greater surface; and this adhesion is competent to separate substances which are so closely and intimately united that everyone would agree to say they were chemically combined. SUPERSATURATION. The fascinating character of the phenomena has attracted a host of experimenters, but no definite conclusion as to an explanation has been generally accepted. Mr. Tomlinson, who a few years ago published many papers on the subject, has given (‘ Proc. R.S.’ xvi. 403) a history of the chief researches up to his time. He has also arranged in five groups the salts he has investigated according as they do or do not yield supersaturated solu- tions, and according to the behaviour of those supersaturated solutions. The following definition of supersaturation is given by Mr. Tomlinson (loc. cit.) : ‘When water at a high temperature is saturated with a salt, and on being left to cool in a closed vessel retains in solution a larger quantity of the salt than it could take up at the reduced temperature, the solution is said to be supersaturated.’ Such solutions crystallise when brought into contact with a crystal of the same salt, or of a compound truly isomorphous with it (J. M. Thomson, ‘ Jour. Chem. Soc.’ 1879). Crystallisation, often in a modified form, is also im many cases brought about when the solution is cooled to a low temperature or evaporated, or when certain absorbent substances, such as paper or plaster, are introduced into the liquid under certain conditions (Jeannel, ‘ Compt. Rend.’ Ixii.; Grenfell, ‘ Proc. Bristol Nat. Soc.’ vol. ii. Part II. 130). It has been supposed by many chemists following the views expressed in the earlier of the well-known researches of Léwel (‘ Ann. Chim.’ [3] KXIX., XxXlii, xxxvii, xliii., xliv.) that supersaturation is due to the 1 Or, in the case of water, a fall in temperature, if below the temperature of maximum density. See V.d. Mensbrugghe, Phil. Mag., [5] 2, p. 450, referring to Jungk’s experiments. Since the above was written some interesting experiments have been published by F. Meissner ( Wiedemann’s Annalen, 1886, p. 114), upon the effect of moistening finely divided silica and other powders with water, benzene, and amylic alcohol. In every case above 0° a very notable rise of temperature was observed. 1886. HH 466 REPORT— 1886. formation of peculiar hydrates containing less water, and more soluble than the normal salt. On the other hand, Lowel, in his last memoir (‘ Ann. Chim.‘ [3] xlix.), recants his earlier belief, and definitely expresses himself in favour of the opinion that a supersaturated solution (referring specially to sulphate of sodium) contains the anhydrous salt, and that no solution can be properly called supersaturated. ‘Dans toutes les dissolutions, quelque riches qu’elles soient, qui ne sont pas en contact avec un excés de cristaux 4 10HO ou a 7HO, les molécules salines dissoutes restent a l’état de sel anhydre, malgré les variations de température, si elles sont préservées de cette action mystérieuse de contact que’ l’air atmosphérique et d’autres corps ont la propriété d’exercer sur elles en déterminant la formation de cristaux a 10HO, et si leur température ne tombe pas 4 un degré suffisamment bas pour déterminer la formation spontanée de cristaux 4 7HO” (‘ Ann. Chim.’ [3] xlix. p. 56). Tomlinson, de Coppet, and other writers have since adopted the same views. De Coppet showed (‘ Compt. Rend.’ lxxii. 1324) that a supersaturated solution of sodium sulphate may be formed by dissolving in cold water the anhydrous salt, provided the latter had been heated above 33°, and preserved from contact with the dust of the air. He also succeeded in preparing supersaturated solutions of sodium carbonate, and magnesium sulphate by dissolving the dehydrated or partly dehydrated salt in cold water. Nicol (‘ Phil. Mag.’ June and Sept. 1885) has made similar observa- tions, and has also shown from density determination of sodium sulphate and thiosulphate of various strengths that in passing the ordinary satu- ration point there is nothing to indicate any change in the constitution of the solution. He therefore concludes that a so-called supersaturated solution is merely a solution saturated or non-saturated of the anhy- drous salt, and that in this respect it differs in no way from an ordinary solution which is not capable of supersaturation. Nicol also considers, as Lowel seems to have done, that any solution of a hydrated salt con. tains no hydrate, but that combination between the salt and the water takes place at the moment of crystallisation. I thought at one time that supersaturation resulted from dissociation of the dissolved salt into water and the anhydrous salt, owing to the action of the higher temperature—above 33°—to which, by the ordinary process of making supersaturated solutions, the liquid is exposed. But before the experiments of De Coppet and Nicol had come to my know- ledge I had satisfied myself that this was not so; for on saturating a solution at the temperature of the air with crystals of sodium sulphate, and then filtering the solution into a stoppered bottle and cooling to about 0°, the cold solution exhibits all the phenomena of supersaturation so long as it is kept at that lower temperature. This is difficult to explain on any hypothesis of dissociation. Supersaturated solutions are at present only known to be formed by hydrated salts, or by anhydrous salts only at such low temperatures that hydrates are formed, e.g., common salt. JI am inclined to the belief that this is due to their much greater fusibility. If we compare the melt- ing-points of those salts which are known to give supersaturated solutions readily with the melting-points of those which, although easily soluble, do not give supersaturated solutions under any conditions that have yet been tried, we see this difference plainly. ON THE PHENOMENA AND THEORIES OF SOLUTION. 467 Salts which readily Melting Points Salts which do not Melti form Supersaturated Approxi- form Supersaturated Poi aes Solutions mate Solutions tance Na,S0,10H,O 34° KNO, 339° Na,CO,10H,O 34° K,Cr,0, 400° Na,HAsO,12H,O 28° NaNO, 316° Na,HPO,12H,O 35° KCl1O, 359° NaC,H,0,H,O 58°5° Ba(NO,), 593° KA1(S80,),12H,0 84:5° &e. Na,$,0,5H,O 485° Mg50,7H,0 70° A supersaturated solution may be regarded as a mixture of a saturated solution, with an extra quantity of the salt retaining a liquid state; in fact, in the condition which is commonly spoken of as superfusion. Now, when we examine cases of superfusion, such as water, melted phosphorus, melted sulphur, phenol, acetic acid, and so on, we find that the liquid state is preserved so long as the liquid is cooled only a moderate degree below its melting-point.' Water may be cooled to 10° or 12° below freezing ; phosphorus, which melts at 442°, can be cooled to the common temperature of the air, say 30° lower; but sulphur, which melts at 115°, cannot be cooled to the air temperature, which is 100° below its melting- point, save in very small drops (Faraday). Melted sulphur may, how- ever, be kept liquid at the temperature of boiling water, if protected from dust, &c. (Gernez, ‘Compt. Rend.’ Ixxxiii. 217), Similarly, super- saturated solutions remain liquid at the common temperature of the air, but crystallise at 20° or 30° lower when cooled by a freezing mixture. The fact is supersaturation is a case of superfusion. Gernez supposed (‘ Compt. Rend.’ 1866, p. 218) that he had discovered a difference between the two when he made the observation that superfused phosphorus and sulphur might be made to solidify by rubbing two hard bodies together under the surface of the liquid, as when the inside of the containing vessel is scratched with a wire or a glass rod. But Mr. J. G. Grenfell showed in 1876 (‘ Proc. R. Soc.’ xxv. 129) exactly the same phenomenon with a solution of sodinm sulphate in sulphuric acid, and it appears to differ in no respect from the well-known effect when solution of platinum per- chloride or of sodium hydrogen tartrate is mixed with a potassium salt and the liquid is vigorously stirred. My view of supersaturation, then, is that it is identical with superfusion. The explanation of the one phenomenon is the explanation of the other. The case of thiosulphate of sodium is a very interesting one. This salt melts at 48°5° without addition of any water whatever beyond what it contains in chemical combination. This salt may be kept in a liquid state in an ordinary flask exposed to the air for weeks. Advocates of the theory which considers supersaturated solutions (and other solutions) to contain molecules of the anhydrous salt in a free state must regard this liquid as a solution of one molecule of Na,S.O, in five molecules of water. I cannot help believing that this liquid is none other than the compound (Na,S,0;5H,0), in a liquid state, just as liquid water is the compound 2 x } There is a commonly recognised difference between melting and solidifying points, but this seldom amounts to more than a few degrees, HH 2 468 ' REPORT— 1886. Since contraction occurs when most solids are dissolved in water, it follows that if the dissolved substance could be withdrawn again without changing the temperature of the liquid expansion would occur. Now super- fused substances (and supersaturated solutions) contract as they solidify, with the single exception (so far as I know) of water, which expands when frozen. If it were not for the declaration of Professor Osborne Reynolds that ‘ dilatancy ’ is nota property that can be exhibited by ordinary matter, but only by such hypothetical stuff as consists of hard, inelastic particles. devoid of cohesion and friction, one would be tempted to try and explain superfusion and supersaturation by appeal to a hypothesis of that kind. Certain it is that in a superfused liquid there exists a condition of strain which is overcome by cohesion only when the latter has been considerably increased by lowering the temperature. And relief from this strain may often be obtained in more than one way, as in the crystallisation of dimorpkous substances like sulphur, and in the deposition of modified salts (such as Na,SO,7H,0O, &c.) from solutions, The fact that in some cases it is possible to reduce the temperature of small drops of a superfused liquid, such as sulphur, much below that at which larger masses can be preserved in the liquid state, seems to show that the surface tension in spheroidal masses operates against the ten- dency to change of state. Whether it is sufficient appreciably to retard the change is more than I can say, but Van der Mensbrugghe ! has shown ‘by mathematical analysis that the potential energy of afree liquid surface increases with the surface, and in this way he explains the very facts to which I have just referred. CONCLUSION. Such facts as these lead us to the consideration of what is meant by chemical combination. Take, for example, a common metallic salt, such as copper sulphate, CuSO,. Here the law of definite proportions being rigidly observed, and the compound being very different in external characters from its ingredients, chemists have no difficulty in agreeing that this is a case of true chemical combination. But when the salt combines with water of crystallisation great difference of opinion arises as to whether the elements thus superadded are chemically com- bined with those of the salt, or whether a new kind of chemical affinity is called into play. The difference is one of degree, not of kind. Blue vitriol is composed of copper sulphate and water united in definite and quite simple proportions, and the chief reason for supposing the water to be combined in a manner different from the other ingredients of the salt is that it can be detached by heat or otherwise more easily, and that it occupies a relatively larger volume. But, as already stated, the water combined with such a salt is attached in different degrees of intimacy, the first molecule occupying a smaller volume than the second, and so on, the act of union of the salt with these successive molecules being attended by the loss of successively smaller amounts of energy. Taking a step further, suppose this salt dissolved in water, the resulting liquid is produced with many of the attendant phenomena which usually accompany recognised chemical combinations—changes of 1¢On the Application of Thermodynamics to the Study of the Variations of Potential Energy of Liquid Surfaces,’ Phil. Mag., 1876 [5], ii. p. 450; and Phil. Mag. 1877 [5], lv. p. 40. ON THE PHENOMENA AND THEORIES OF SOLUTION, 469 volume, of specific heat, and thermal changes, positive or negative. The same may be said of the act of diluting this solution. More water (or more salt) being added, similar physical phenomena are exhibited ; and it is important to notice, as already stated more than once, these changes are all continuous one with another, the specific volume of the added water constantly tending towards that of water itself. The conclusion seems inevitable that chemical combination is not to be distinguished by any absolute criterion from mere physical or mechanical aggregation, and it seems not improbable that it may ultimately turn out that chemical combination differs from mechanical combination, called cohesion or adhe- sion, only in the fact that the atoms or molecules of the bodies concerned come relatively closer together, and the consequent loss of energy is greater. The researches of Miiller-Erzbach, published in a long series of papers (especially ‘ Ber.’ 1880, p. 1658, and 1881, p. 217), strongly support such a view. He has shown by numerous examples that in similarly constituted solid bodies those are the most stable in the formation of which the greatest contraction occurs. Thus when lead replaces silver, or potassium replaces sodium in the nitrate, or when chlorine replaces bromine or iodine in combination with another element, contraction occurs. And in general, contraction is observed when an element of reputed strong affinity (as indicated by the results of thermo-chemical experiment) takes the place of one of reputed smaller affinity. This is only an extension of what has already been observed in the combination of water with salts, and which in all probability applies generally in the comparison of atomic combination as distinguished from so-called molecular combination. We are in the habit of using the word ‘attraction’ in a somewhat indefinite and unsatisfactory manner in referring to the hypothetical cause of the union of atoms or molecules. Wedo not know what this thing is which is called chemical affinity or attraction. There can be little doubt, however, that it is connected intimately with atomic or molecular motion. It does not require a great stretch of imagination to conceive that combination occurs most readily and intimately between those atoms or molecules whose motions are nearly alike. And confining our attention to the phenomena now under discussion, it seems not improbable that this may be the explanation of the selective action of solvents, and the disposition so often shown for like to dissolve in like. It may also, perhaps, go some way towards explaining the great amount of heat evolved and the great contraction which ensues when many anhydrous salts are brought into contact with water, as compared with the effects of dissolving the same salts when in the hydrated state. On the Exploration of the Raygill Fissure in Lothersdale, Yorkshire. By James W. Davis, F.G.S. [A communication ordered by the General Committee to be printed in extenso among the Reports. ] Tue Raygill Fissure, in the mountain limestone in Lothersdale, about five miles south-east of Skipton, was investigated to some extent by a Committee of the Association, and a report was presented by 470 REPORT— 1886. the Committee and printed in the Annual Report for 1883. |The fissure descended in a slightly diagonal direction in the form of a pothole from the surface to a depth of about 120 feet, and of this depth the lower 90 feet has been dug out and thoroughly examined, resulting in the discovery of numerous bones of animals, particulars of which are re- corded in the report referred to above. The specimens are deposited in the Museum of the Philosophical and Literary Society at Leeds. Towards the close of 1883 it was found that the fissure assumed a more or less horizontal direction, and the work of excavation was rendered very diffi- cult and laborious by the position of a large mass of limestone in front of the fissure, constituting at that time the face of the quarry. ‘ This obstruc- tion the proprietor of the quarry very kindly engaged to remove, and operations were suspended to enable this to be done. Since 1883 the face of the limestone has been quarried and the ob- structing mass of limestone removed, and during the present summer operations have been renewed on the fissure. Its course has been traced to a distance of 114 feet, with a gradual declination in a south-easterly direc- tion. The present entrance to the fissure is 4 feet wide: it diminishes to 2 feet 6 inches, but at a distance of 60 feet expands and forms a lofty cave, thence forwards the diameter again diminishes. The termination of the fissure so far as it has been explored appears to receive a tributary extend- ing almost vertically in a north-westerly direction. The general direction of the fissure tends towards the hillside, forming the channel of a water- course at present running at no great distance; and it is probable that it formerly opened into it, although no direct evidence at present exists of the exit. Borings have shown the bottom of the fissure to be filled in with clay varying from 6 inches to several feet in thickness, with slight alternating layers of sand and gravel, and occasionally fragments of grit and limestone at the bottom. A few remains of mammals have been found near the entrance to the horizontal portion of the fissure similar to those already recorded. At the meeting at Montreal in 1884 a grant of 15]. was made for the further exploration of the cave. This sum has been expended in the operations described above. A very much larger grant would be required to investigate the remaining length of the fissure, because the work will be increasingly laborious, and the consequent expense proportionately heavy ; and as there is no probability indicated in the work so far that the already large series of animal remains will be greatly, if at all, increased, it is not thought advisable to ask for a renewal of the Committee or grant. In conclusion, it is desirable to render thanks to Mr. Spencer, and latterly to his son, the proprietors of the Raygill Quarries, for their permis- sion to carry on the work, and for the uniformly kind and courteous manner in which they have always placed themselves at the disposai of the Committee; and to Mr. J. Todd, the manager of the works, for the trustworthy and careful manner, combined with much skill, in which he has superintended the operations of the workmen employed. ON SILICA IN AN IGNEOUS ROCK. 471 An Accurate and Rapid Method of estimating the Silica in an Igneous Rock. By J. H. PLAYER. [A communication ordered by the General Committee to be printed in extenso among the Reports. | PREPARE a flux by intimately mixing together two parts of bicarbonate of soda, two parts of bicarbonate of potash, and one part of nitrate of potash, all finely ground. The mixture must be heated until dry and perfectly pulverulent. In a platinum crucible, six centimetres high, mix thoroughly half a gramme of the very finely powdered rock with one gramme of the flux, place a cover on the crucible, and heat the contents to fusion. With a Fletcher’s gas crucible furnace, the chimney being used, com- plete fusion can be effected in five minutes, with a small blowpipe gas furnace in three minutes. Working with rocks containing not less than 45 per cent. of silica [ have never found a crucible attacked. I have not used the process with less siliceous rocks. After fusion remove the cover from thecrucible and replace it by a small glass funnel cut off at the apex of the cone; then, without waiting for the fused mass to cool, pour in it through the funnel 3 cc. of strong nitric acid. Energetic action ensues, but there is no projection of the solid or fluid contents of the crucible. Place it at once on a water bath and keep it for ten minutes at a temperature of 100°C.; at the end of that time if all hard and dark particles have not disappeared add 2 ce. of nitric acid, stir with a platinum rod, and continue to heat. As soon as the disintegration of the glass is completed wash with as little water as possible the crucible cover, funnel, and rod, then evaporate the jelly and the washings to- gether. After having driven off the greater part of the water, when there is no longer any fear of projection, remove the crucible to a sand bath and heat just below 250° C. until all nitrous fumes shall have dis- appeared. The operation has up to this point been carried on in one vessel; now turn the mass into a small glass beaker, washing the crucible, first with 5 cc. of water, then with 3 cc. of hydrochloric acid; heat the beaker to 100° C., that the bases may be quickly dissolved by the acid, until the silica left be white and free from red specks ; add now more water and pour the contents of the beaker on to a 590 Schleicher and Schulls filter, placed over a filter-pump ; drain as dry as possible, and calcine at once in a small crucible. Weigh the crucible and its calcined contents, con- sisting of silica mixed, if these bodies be present in the rock, with minute quantities of iron oxide and alumina, and a much larger quantity of titanic acid. After weighing moisten very slightly with four or five drops of strong sulphuric acid, stir the moistened silica with one gramme of perfectly pure ammonium fluoride, put a cover on the crucible, and heat it, first of all gently, then more strongly, finally to a full red heat. If the few milligrammes left in the crucible are not perfectly soft repeat the process; but this it should not be necessary to do. The weight of the crucible and the calcined residuum haying been ascertained, it must be deducted from the previously recorded weight ; the ieee will give the weight of the silica present in half a gramme of the rock. 472 Ereal Hill Granulite—Red Rock. REPORT— 1886. Ereal Hill—Grey Rock. Sp. Gr. 2°575. Sp. Gr. 2°508. Water . A : * 5 Loss by calcination, ? water 15 Silica . ‘ . 4 . 68 Silica. 5 : : Sivoo Titanic acid . = 6 : 4 Titanic acid . : é 4 3 Alumina : . é Pie aie! Alumina 2 : J pi et Ht Peroxide of iron 6 Peroxide of iron . 3 a ee Protoxide of iron 1 Protoxide of iron 7 3 Lime ‘ 4 ; 3 . trace Lime . 3 4 A . trace Magnesia : A a . trace Magnesia + < 5 : 2 Potash . ; rf ‘: sO Potash . 3 4 3 5 M28 Soda 5 3 : 3 Say Lr Soda - é f en? 429 100°2 99°6 Lea Rock Rhyolite. Sp. Gr. 2°590, Quartz Felspar, Malvern—Red Rock, Coarse Granitic Texture. Water 5 5 > ‘7 Sp. Gr. 2°594. Silica. - . : . 54 Water ; : : i re Titanic acid Ha simudi 02 Silica. - +e 752 Alumina E BS BY Titanic acid . . 3 - 32 Peroxide of iron ; ; 8 Alumina. : ° : Es0 Protoxide ofiron . . . ‘6 Peroxide of iron 7 Lime 7 . ¢ “4 Protoxide of iron 3 “4 Magnesia : ; - 2 Lime. : . 4 r 4 Potash . ; ‘ i ay 7: Magnesia : é ‘ ay Soda { 2 2 NET Potash . . 5 3 eG! j Soda : . 19 Quartz Felspar, Malvern, North Hill. Quartz Felspar, Malvern—Red Rock Sp. Gr. 2°601. (fine-grained). Water . : 3 5 8 Sp. Gr. 2°604. Silica . , ; d . 746 Water . : ‘ i 9 Titanic acid . j ; . none Silica 2 75:2 Alumina F : . . 14:2 Titanic acid 2 Tron peroxide . , : idl? Alumina 13:7 Iron protoxide erly Reishane ae brace Peroxide of iron 1:3 Lime 4 , : - ‘ “4 Protoxide of iron 6 Magnesia 2 ee ee eS Lime — 4 Potash . : : : o Ag Magnesia 3 Soda 5 ; : : enS:7, Potash . " 4:0 —-- Soda . 5 . 2°6 100°1 99-2 On some points for the Consideration of English Engineers with reference to the Design of Girder Bridges. By W. SHELFORD, M.Inst.C.E., and A. H. Suretp, Assoc.M.Inst.C.£. [A communication ordered by the General Committee to be printed in eawtenso among the Reports. | ENGINEERS with an eye for bridge-building cannot fail to be struck by the difference in general appearance between English, German, and American bridges. The ordinary plate-girder unquestionably finds more favour in England than elsewhere, while in Germany it seems to have ON THE DESIGN OF GIRDER BRIDGES. 473 been more or less discarded in modern practice, and is replaced by lighter structures, designed with a more scientific disposition of the material, and constructed chiefly of angle and bar iron. Both in Germany and in America the modern practice appears to be to adopt large panels and great depth—a system of construction which has been greatly facilitated by the use of steel, owing to the greater length of the bars and plates procurable in that metal, and the consequent diminu- tion in the number of joints. In America, also, pin-jointed bridges are the rule, and riveted joints the exception—exactly the reverse, in fact, of the English practice—and the deep pin and link truss, with a straight top boom and long panels, there almost the universal method of construction for spans over 75 feet, differs in a striking manner from both English and German bridges. Its construction has been brought to considerable perfection, and appears to be eminently suitable for a country where distances are great, labour scarce and expensive, and rapid construction of the utmost importance. By this system the Americans are able to turn out a bridge with the greatest accuracy and expedition, and can erect it without previous erec- tion in the shops, and with little staging, in an incredibly short space of time. In England, on the other hand, a strong bias among engineers in favour of riveted joints has led to the absence of special appliances for the manufacture of pin and link bridges; and the practical advantages of the system are less esteemed, as English engineers do not push forward their railways so rapidly as the Americans. As most English railway engineers must now look chiefly to the development of new countries for future work these general facts should be sufficient ground for an examination of their practice; but if more definite reasons are sought, reference may be made to the case of Canada, where English engineers, who built the first bridges, have since been superseded by Americans. The design of a bridge of exceptional span is almost invariably the subject of special study, to an extent which is inadmissible in the case of bridges of ordinary size. These are usually constructed in accordance with a limited number of standard types, which experience has shown to be suitable; and it is to these only that such general considerations as have been suggested properly apply. The economic importance of smaller bridges is also greater, and it is to bridges of spans less than 200 feet, which, with reference to the American system, may be termed ‘merchantable’ sizes, that the scope of this paper is therefore limited. In order to ascertain the extent to which the weight of such bridges is affected by their design, seven designs were chosen for bridges of 140 feet span for a double line of railway. The designs were selected to represent leading English and American types; their strength was deter- mined by a rolling load of 12 ton per lineal foot for each track; and their weights were estimated, including flooring, rail bearers and cross girders, and the necessary stiffening or bracing for wind pressure and lateral oscillations. Particulars of the design and weight of each bridge are given in the following table :— 474 REPORT—1886. | _ Estimated weights No. Description Length of panel | Depth of girder | Main Plat girders fun ~ | Total (2) Tons | Tons | Tons 1 |‘N?’ or ‘Pratt’ (riveted) 8 ft. 12 ft. 104 86 190 2 | Bowstring (riveted) . 8 ft. Sin. 18 ft. (db) 95 86 181 3 |‘ Whipple’ (pin con- 8 ft. 18 ft. 89 86 175 nected) 4 | ‘Neville-Warren’ (partly 8 ft. 9 in. 18 ft. 83 86 169 riveted) 5 |*N’ (in connected), or- 17 ft. 6 in. 24 ft. 75 81 156 dinary American type 6 | Polygonal (riveted) : 20 ft. 26 ft. 3in. (bd) | (e) (c) 154 7 |1*N’ @inconnected . 24 ft. 24 ft. 68 84 152 (a) includes wind-bracing ; (J) at centre ; (¢) inseparable. Plate floors were adopted in all these bridges in order to enable a comparison to be made between their weights, although in America they would be replaced by heavy timber decks with diagonal bracing of iron rods. Nos. 1 and 2 derive lateral stiffness entirely from the plate floor, and owe their transverse stability to the connection of the verticals to the cross girders by knee pieces, aided in the case of the bowstring girder by light overhead stays at the centre. In Nos. 3 and 4 the depth (18 feet) admits of a complete system of lateral bracing between the top booms, so that the transverse stiffening is confined to the ends; their relative advantages are discussed at length by Mr. C. Bender in his recent book on the Economy of Metallic Bridges,! and preference is given by him to the Whipple truss. No. 5 is an ordinary type of American bridge ; the lateral stiffness of the bottom is derived from the plated floor, and it has top lateral bracing and transverse stiffening at the ends, as in Nos. 3 and 4. No. 6 represents an attempt to apply to the conditions of the problem the principles enunciated by Mr. Max am Ende in a paper recently read before the Institution of Civil Engineers.? The girders are polygonal; lateral stiffness is derived entirely from the floor; and trans- verse stiffness is obtained by combining each of the cross girders with the verticals and overhead stays into a rigid frame. No. 7 was suggested by the central span of the Niagara Cantilever bridge, and has a wind system similar to that of Nos. 3, 4, and 5. From these examples it will be seen that the difference in weight of good designs of the same depth is comparatively trifling, and is not greater than might be compensated by local considerations ; such as the relative cost of labour and material; facilities for erection; and the differ- ence in cost of various methods of construction ; while the fundamental principle that the weight of a girder decreases as the depth increases is generally applicable to an extent which, if recognised in theory by English engineers, has not hitherto found general expression in their practice. The extra depth required for the rail-bearers in bridges with long panels is, however, in England, where the headway is frequently very 1 The Principles of Economy in the Design of Metallic Bridges. By Charles B. Bender. New York, 1885. 2 Minutes of Proceedings Inst.C.H., \xiv. 243. ON THE DESIGN OF GIRDER BRIDGES. 475 limited, more often than elsewhere prohibitory of the adoption of the most economical form for the main girders; and although the question of design requires careful study, there is no evidence of the existence of inherent national errors or prejudices in design which would be likely to place English engineers at a disadvantage in dealing with colonial work, or to account for the fact that they have lost it in Canada, and recently in one case in Australia. It has been suggested that the position of the designer in America is more favourable to economy of construction. In America when a bridge is required the railroad company invite tenders for its construction and erection in accordance with their speci- fication, which generally states the class of bridge preferred, the load which it is to carry, and the quality of the material, and defines in con- siderable detail the stress to which its parts may be subjected. The design is left to the bridge company tendering for its construction, but it is required that sufficient information shall be supplied with each tender to enable the railroad engineer to examine the proposal and determine whether it fulfils the required conditions. The designer, who is consequently employed by the bridge company, has in the first place to produce the most economical structure, while the primary responsibility for its safety lies with the railroad engineer who has prepared the specification, and will be enabled to check the corre- spondence of the design with his requirements before the tender is ac- cepted, and to make the necessary modifications—a work of considerable difficulty unless the design is a good one to begin with. The English designer, on the other hand, has in the first place to design a safe structure, since he is seldom immediately subject to competition in respect to its economy, and is entirely responsible for its security. The English system has advantages with respect to security; while its economic disadvantages are that the engineer is seldom able to ascertain either the exact cost of his designs, or the relative economy of their details, nor has he any personal interest to serve, or any other in- ducement to reduce the cost to the lowest point. The system moreover entails a want of correspondence between the design and the appliances of the manufactory, where it is afterwards executed, especially if the work is let by open tender. These disadvantages are accidental rather than essential in their nature, and this should suggest their remedy in detail rather than the condemnation of the system under which they arise. Much could be effected by manufacturers to promote economy in design by the publication of particulars of the relative cost of different details of construction, in such a way as not to injure their commercial interests. It is also an open question whether standard sections could not be adopted for the usual sizes of angle, tee, and other rolled bars, so that no difficulty need arise—in this respect at least—in making the design in accordance with the scantling of the materials readily available for its manufacture. Both the design of bridges generally, and the personal position which the designer should occupy, are matters which may be left entirely to the discretion of those concerned ; but engineers are in England very properly subject to a certain degree of Government supervision in regard to struc- tures which directly affect the safety of the travelling public. A476 REPORT—1886. The Board of Trade have exercised since 1840 a statutory power of inspecting arid testing bridges on railways for passenger traffic, and have issued rules for the guidance of engineers in designing these struc- tures, which have been generally accepted as applicable to all bridges, and exercise a strong influence over English engineersin their use of iron and steel in all permanent engineering structures either at home or abroad. It is provided by these rules that the greatest strain produced by the combined moving and dead load on any part of a structure shall not exceed, for wrought iron five tons, and for steel six and a half tons, per square inch. No defined quality or strength is required in order that either material may be subjected to these stresses, but in the case of steel the engineer must certify that it is possessed of considerable toughness and ductility, and state the tests to which it has been subjected. : It is also provided that the heaviest engines, boiler trucks, and travel- ling cranes in use on railways shall be a measure of the load to which bridges may be subjected. For convenience the strength of bridges is usually measured by an assumed uniform load per foot run, intended to cover the weights of the heaviest engines and trucks. [The manner in which this equivalent— for the same actual load—varies with the span of the bridge, was shown by a diagram.!] This diagram showed how important the rolling load becomes in small girder bridges, and in the floors of large bridges—matters which have certainly not been properly considered in numerous existing examples in England. The determination of the greatest load to which a bridge may be subjected, also affords an excellent example of the insufficiency of any rules, however perfect, to relieve the engineer of a large amount of responsibility. The origin of the rules may be traced in the Parliamentary Reports of the Board of Trade, and of the Railway Commissioners who from 1846 to 1851 exercised the powers of the Board of Trade with respect to railways. From these reports it does not appear that previous to 1849 the inspecting officers had a defined rule for the strength of bridges either of wrought or cast iron. In 1847, however, a Royal Commission was appointed in the following ‘terms :— ‘To enquire into the conditions to be observed by engineers in the ap- plication of iron to structures subject to violent concussions and vibra- tions ’ and ‘ to endeavour to ascertain such principles, and to form such rules, as may enable the engineer and mechanic to apply the metal with confidence, and to illustrate by theory and experiment the action which takes place under varying circumstances in iron railway bridges which have been constructed.’ The terms of this Commission clearly indicate that the interest of the engineer was to be studied as well as the safety of the public. The Commissioners were Lord Wrottesley, then President of the Royal Society ; the Rev. Robert Willis, M.A., an eminent mathematician ; ' The results deduced from this diagram are given in the Appendix in Schedules A and B. ON THE DESIGN OF GIRDER BRIDGES. 477 Capt. Henry James, of the Portsmouth Dockyard; and three civil engi-- neers, Messrs. George Rennie, William Cubitt, and Haton Hodgkinson. After examining the leading engineers and ironfounders of the day as to their experience and practice, and making numerous and elaborate: experiments, the Commissioners reported that ‘ legislative enactments. which would fetter scientific men in the development of a subject as yet so novel and rapidly progressive would be highly inexpedient.’ They, however, made certain recommendations with respect to cast- iron bridges, which are substantially the same as the present rule for’ cast-iron structures—that the breaking weight should be six times the moving load added to three times the dead load. They also made a further recommendation, applicable to all elastic: horizontal bridges, that provision should be made for the increase of strain in bridges under 40 feet long when subject to a rapidly moving load, as: indicated by the increased deflection in such cases—a recommendation which until recent years was lost sight of. These recommendations were, immediately upon the publication of their report, embodied by the Railway Commissioners in a circular letter of instructions to their inspecting officers. On the day following the date of this letter Capt. Simmons inspected. the Torksey Bridge, a wrought iron box-girder bridge of two continuous. spans of 130 feet, designed by Mr. (now Sir) John Fowler, and objected to it as of insufficient strength. Its rejection was discussed by the Institution of Civil Engineers, and the Railway Commissioners were accused of applying to wrought iron the recently published recommendation of the Commission on Iron, requiring a factor of safety of six for cast iron bridges. At the same time a lengthy correspondence took place between Mr. Fowler and the Commissioners, and Captain Simmons decided—after the examination of such examples as were available—that the bridge should be strengthened so that the strain should not exceed five tons per square inch. In fixing this he admitted that there was no decided authority upon the subject, and that the variation in the circumstances of the construction of bridges prevented the application of an invariable law. He recognised as a principle the variation of the admissible strain in a bridge according to the proportion of live to dead load—a point which has been recently revived. In the end—after a special examination to test the continuity of the spans—the bridge was accepted with a strain under the most favourable estimate of slightly over six tons per square inch. Between 1850 and 1858 the rule for cast iron bridges appears to have found general acceptance, while there is conclusive evidence of the ab- sence of a defined limit for the strain in wrought iron structures. In 1858 a wrought iron tubular girder bridge over the Spey was brought before Captain (now Sir) Henry Tyler some time before its com- pletion, and a lengthy correspondence ensued between Captain Tyler and Mr. Fairbairn with reference to its strength. This correspondence Captain Tyler laid before the Board of Trade, who, on March 30, 1859, issued a circular letter of instructions fixing five tons per square inch as the proper limit of strain for wrought iron. Upon this Captain Tyler based his rejection of the bridge on April 30. It is very important to note that this rule was explained at the time by Captain Tyler to represent a factor of safety of four for combined 478 REPORT— 1886. moving and dead load. It has not since been altered, and in practice itis assumed to be applicable to all wrought iron, whether the quality be good or not. Among the numerous considerations suggested by the survey (after the lapse of over 25 years) of the period of which a brief sketch has been given, the most striking is the confirmation which experience has given to the conclusions of the Commission of 1847. Derived from the interpretation by skilled mathematicians of the results of experiments conducted by practical engineers, combined with the evidence of the ablest engineers of the time, their conclusions were based upon a solid foundation of fact and experience. Their recommendations, although jealously resented by civil engineers at first, notwithstanding the avoidance of legislative interference, by which freedom was secured for the development of engineering science, Jed, under the judicious interpretation of the inspecting officers, to the present rule for cast iron structures. This rule is good in principle because it derives the load—and consequently the stress—to which the structure may be subjected, from the actual strength of the material. The present rule for wrought iron has no such foundation, and it is indeed only due to the high professional attainments of the inspecting officers, and the sound judgment and great moderation with which they dealt with the difficulties which naturally arose when wrought iron first became generally used, that the present rule, introduced without special experimental research, has endured so long that it has obtained the sanction of what—to younger engineers at least—is an immemorial usage, taken for granted and stereotyped beyond reach of improvement. Its principal fault is in allowing a fixed limit of stress without regard to the quality of the material. This does not lead to serious results so long as the limit of five tons per square inch is understood to represent a factor of safety of four applied to iron having a breaking strength of not less than twenty tons, as explained by Captain Tyler in 1859; but it must not be forgotten that the rule itself is used by many who do not know its origin, and the absence of any stipulation as to the strength of the mate- rial leads naturally to the assumption that five tons represents the safe working stress for any quality of iron in the market; and many inex- perienced engineers do so interpret and use it. It is hardly necessary to state that there are many qualities of iron for which such an assumption would be attended with considerable danger, but it is not so apparent that a bridge made of utterly untrustworthy material might not, under the ordinary tests, afford any indication of its insecurity. Such is, however, the case, and the safety of the public depends, in this respect, very much more upon the choice of a suitable material by the engineer than upon the Board of Trade rule. A fixed limit of stress without regard to the quality of the material also restricts the engineer in the development of economic design in the direction of a greater use of better material, such as angle and bar iron of superior strength and ductility. Nor does a fixed stress offer any induce- ment to the manufacturer to improve the quality of plates. These considerations apply with much greater force to the present rule for steel. As a material, steel is much more variable in its strength than iron, which renders the application of an invariable coefficient more objectionable. It is true that the Board of Trade, in accordance with a recommenda- ON THE DESIGN OF GIRDER BRIDGES. 479 tion of the Committee of 1877 appointed at the instance of the British Association, allow in special cases the use of steel with a higher stress, but exceptions of this nature are naturally ill-adapted to the design of bridges of ordinary spans. The rules cannot be regarded as suited to the nature of the material, and there can be little doubt that they have operated to hinder the appli- cation of steel to uses for which it is admirably suited, and have thus exercised a prejudicial effect upon one of the leading industries of the present day. Unless the rules which determine limiting stresses or coefficients for iron and steel can be brought into conformity with modern knowledge of the properties of materials, and of the laws by which their application to construction should be regulated, their entire abolition would be prefer- able, because it would conduce to the advancement of engineering science, and the development of the bridge-building industries. The safety of the public need in no respect be compromised by the abolition of the limiting stresses, if the rules requiring the engineer to certify the quality of the material used were retained (and extended to apply to iron as well as steel) in order to provide the inspecting officer with all the information requisite to enable him to judge whether the stress to which a structure was subjected was within safe limits. Freed from the deadening influence of the fixed coefficients, private enterprise would establish standard rules for the determination of the stress to which different materials under varying conditions might safely be subjected; to the great advantage of the professions and trades in- terested in bridge-building, and having in future to compete with the Americans. ¢ On the other hand, there are many objections to such a course, which would practically amount to a reversion, after the experience of thirty years, to the conditions of 1850. It is also to be feared that during the time which must necessarily elapse before any rules obtained the sanction of a common assent, differences of opinion causing much inconvenience would probably arise between civil engineers and the inspecting officers of the Board of Trade—which is much to be deprecated. A course more worthy of the scientific attainments of English engineers would be the amendment of the rules; so that, while leaving to the engineer the greatest possible freedom in the choice of design and material, and leaving in his hands the responsibility for the correct determination of every effect of the loading of a structure which the most modern methods render calculable, they should determine for his guidance by coefficients based upon experience, or where practicable upon experimental research, the proper allowance to be made severally for each of all those effects which are usually understood to be covered by the present arbitrary factor of safety. Rules so designed could not fail to exercise an elevating effect on the professional knowledge and skill of engineers, by affording a more distinct _ conception of the effects for which the factors of safety provide; and by _ abolishing the use of coefficients, of which neither the origin, scope, nor intent is known to the user. The division of the factor of safety into many separate coefficients, some of which would vary with the quality of the material and character _of the workmanship, would encourage good workmanship and the use of materials of a high class, without restricting the use of materials of a 480 REPORT—1886. lower class and less perfect workmanship for purposes to which they are adapted ; and would thus be in the highest degree beneficial to the manu- facturers’ interest. These results can hardly be attained otherwise than by rules framed upon the recommendations of a Royal Commission, who could bring to their aid the experience of the inspecting officers and of the leading engineers and manufacturers, and institute special experimental research to elucidate any doubtful questions. Such a Commission would indeed. be but a revival of that of 1847, to complete the work which the former Commissioners were compelled to abandon in 1849, because the applica- tion of wrought iron to engineering structures was yet in its infancy, and steel in its modern form unknown; and the scope of their enquiry could hardly be better defined than in the terms of the former Commission. The draft rules appended have been prepared to show that the views above expressed are capable of taking a practical form, and to render more easily apparent the advantages claimed for them. Abstract of Suggested Rules for the Control by the Board of Trade of the Design of Structures of Wrought Iron and Steel. Note.—The formule and numerical values inserted are intended merely as suggestions of theories requiring further investigation for their establishment, or as estimates of the values which experimental research or experience would assign to the various coefficients. Rutz 1.—Structures of wrought iron or steel to be so proportioned that the calculated stress in any part due to the weight of the structure, together with the moving load set at rest upon the structure, shall not exceed that specified under Schedule D. Stresses due to wind alone not to exceed 14 times, and stresses due to the combined effect of wind and load 1} times the specified stresses. Rute 2.—Provision to be made for moving loads upon main girders, platforms, and bracing, according to Schedules A, B, and C. Rute 3.—All structures to be designed to resist lateral forces, in- cluding not less than 30 lbs. per square foot for wind pressure. In lofty or exposed situations greater allowance to be made for wind. Roe 4.—Engineer to certify, both for iron and steel, that the material used is, in his opinion, suitable for the purpose to which it is applied; and to supply a statement of all the tests to which it has been subjected, in- cluding in all cases those required for the determination of the working stress under Schedule D. ; Schedule A. Equivalent uniformly distributed load for designing girders of which the cross section is varied, based upon the formule 25 =160+— w + S in which S=span in feet, and w=load in tons per lineal foot for one track estimated to produce at any point in a beam a moment of flexure equal to or greater than that produced by any arrangement of the heaviest engines and boiler trucks. ON THE DESIGN OF GIRDER BRIDGES. 481 Spaninfeett . . 8 10 15 20 30 40 50 60 80 100 Load in tons per footrun . 4°72 4:10 3:27 2°85 2°43 2:23 2:10 2:02 1:91 1:85 Schedule B. Equivalent uniformly distributed load for designing bridges of uniform section and depth, based upon the formule For spans under 12 feet wesc S For spans of 12 feet and upwards w = 160+" in which w=Iload in tons per lineal foot for one track estimated to produce a maximum moment of flexure equal to or greater than that produced by any arrangement of the heaviest engines and boiler trucks. Ppan in. feeb co. ss 8 10 15 20 25 30 40 50 60 Load in tons per foot run . 4°50 3°60 2°85 2°60 2:43 2°31 2:16 2:05 1:99 Schedule C. Table of the greatest ‘panel’ or cross-girder loads derived from the formula For panels over 6 feet in length W=1°60 P4+—. oe +p in which W=panel load in tons for one track, and P=length of panel in feet. Length of panel in feet . 0 to 5 6 Bo po hOst SUA op! Ds. ) 425 Loadintons ... . 180 184 22:3 260 296 431 51:4 The above represent the maximum load ona single panel, but the greatest mean load on N consecutive panels might be taken as N4i+2 +145 Schedule D. Admissible stress in wrought iron and steel under varying circum- stances. 1. In cases where the material is subject to stress of one character only. (a) Limiting working stress under any conditions ONC in which a is the greatest stress to which the material may be subject under any conditions of loading; ¢ is the ultimate tensile strength of the material determined by experiment; C, product of all the tabular coefficients of safety (Table, p. 483) applicable to the particular case ; N, a coefficient intended to ensure that the greatest actual stress, in the extreme case of the coincidence of all the conditions detrimental to the resistance of the material represented by the tabular coefficients, shall not reach the limit of elasticity. 1886. II 482 REPORT— 1886. N For wrought iron . » 2°25 For steel, ‘tensile strength under 30 tons per square inch . 2°00 4, . 32 rs if . 2°04 ? 9 35 3? ted » 2-11 ” ” 40 9 ” # 2°22 ”? cr) 45 ” ” e 2°35 3) ” 50 Ped 3? ¥ 2°50 As itis of the utmost importance that steel should be uniform in strength, if the greatest tensile strength when tested exceed the least by more than 15 per cent., the limiting stress shall be reduced. Percentage of variation in tensile strength. . je 16, 20,., 30,40; .SOsanimore: Percentage by which the limiting working strength should be re- duced (arbitrary). . a+ a, 221, 374, 50. (6) Ductility required in : order that any be may safely be sub- jected to the limiting working stress (a), to vary with the proportion in which the stress is caused by a varying or live load ; and may be deter- mined from 6 = 50 (1-4) in which 6 = percentage of contraction of area of fracture under tensile test, and ¢ (as in the Launhardt-Weyrauch Formule) denotes ratio of constant to total load. Cy =1:00 0°80 0°60 0:50 040 030 0:20 010 0:00 1—¢ =0:00 020 040 050 060 0:70 0:80 0:90 1:00 6 te 1 Es 25 30035 Sa 50 Materials which do not exhibit the ductility required by the conditions under which they are strained are only to be subjected to a stress b=ak, in which b is the admissible stress in a material of which the actual eon. traction of area is A, used under conditions of loading for which the required ductility is 6, and k is a coefficient derived from the empirical formula 2 k hk Ratio of actual to | : “ie | = +, | Ratio of admissible to | Solgee: Fe limiting stress ; k é i 8 4 if | =|— 1:00 1:000 0°65 0°836 0°30 0'667 0°95 0-976 0°60 0°813 0:25 0:640 0:90 0-950 0°55 0-790 0°20 0°612 0°85 0:928 0°50 0766 0-15 0°578 0°80 0:905 0°45 0°743 0:10 0°537 0-75 0-882 0-40 0-719 0:05 0-483 0:70 0-859 0°35 0:694 0:00 0:000 2. In cases where the material is subject to tension and compression alternately. ON THE DESIGN OF GIRDER BRIDGES. 483 The admissible stress to be less than when subject to tension or com- pression alone, and may be determined from the formula ie , Max. B’ ca ( ” Max. B in which }’ is the admissible stress in a bar subject to alternate stresses of which Max. B’ is the numerically lesser, and Max. B the numerically greater, and by the admissible stress in the material for ¢=0. This expression is derived from that of Dr. Weyrauch by substituting for the coefficient derived from the primitive strength of the material by an arbitrary factor of safety, the value of bo, determined by the preceding formula with respect to the ductility of the material. Table of Coefficients of Safety. 1. For vibration, shock, and other dynamic effects. For wrought iron or steel ; minimum 1°33 for structures over 25 feet span, for 20 feet span 1:42, for 15 feet span 1:60, for 10 feet span 1°75. 2. For unequal distribution of stress and secondary stresses. Mini- mum for wrought iron 1°20, for steel 1:40. Additional for bracings generally :—In pin-jointed structures 1:05 ; in riveted structures where the breadth of bars is less than ;1,th length of bay or depth of girder, depth of girder is greater than 3th span, and bars are not joined at cross- ings 1:10; in riveted structures otherwise 1:15. Additional for steel plate girders 1:10. 3. For ambiguity of stress or failure of continuity. Minimum 1:00. ee ambiguous systems of bracing 1°33, for continuous girders generally 4. For errors in design and workmanship. Minimum, 1:03. Addi- tional for punched holes:—In iron plate girders 1:05, in iron framed structures 1°15, in steel plate girders 1°15, in steel framed structures 1°30. 5. For irregularities in section and rusting generally 1:03. (Product of minima coefficients for iron 1:70, for steel 1°98.) The specified coefficients of safety are not intended to include pro- vision for increase of stress due to an obvious want of symmetry in the attachments or section of members ; bending stress due to their weight, or liability of struts to buckling: these and other calculable additions to be made to the stresses estimated from external loading. In the case of solid beams or plate girders, the admissible stress to represent the extreme fibre stress; accepting the ordinary theory of bending. Experimental determination of resistance to flexure is recommended in the case of solid beams of unusual section. For solid round pins the extreme fibre stress may exceed the specified stress by 33 per cent. in iron and soft steel, and 20 per cent. in hard steel. Shearing stress in general to be taken as +ths the admissible tensile stress in the same material, but when of different materials the shearing strength of rivets and pins to be based upon the strength of the materials of which they are made. Coefficients applicable to members joined to be applied to joints. Pressure on bearing area not to exceed 1°5 times the admissible tensile strength of the weaker material, whether of rivet, or pin, or that in which the hole occurs. 112 484 REPORT—1886. The Sphere and Roller Mechanism for Transmitting Power. By Professor Hee Suaw and Epwarp Suaw. [A communication ordered by the General Committee to be printed im extenso among the Reports. | [PLATES VIII. and IX. ] A PAPER was read by Professor Hele Shaw before Section A at the Montreal meeting of the British Association, in which the principle of the ‘sphere and roller’ mechanism was explained, and certain applications of it suggested (see p. 631, Report for 1884). A subsequent paper on the: ‘sphere and roller’ friction gear was read last year before Section G@ at Aberdeen (see p. 1193, Report for 1885). The latter paper gave the results of actual trial of the mechanism, and described a machine for transmitting 2 H.P., but it specially dealt with the modes of obviating the various difficulties experienced in the course of bringing the mechan-. ism into practical operation. Since that time Mr. Edward Shaw has been engaged in the develop-- ment of the mechanism, and the present paper contains (1) a brief descrip-. tion of the various machines constructed since the reading of the previous. papers ; (2) an account of certain details of construction which have been introduced in these machines in order to meet novel difficulties; (3) cer- tain data derived from actual work and from special experiments by both the authors in connection with points concerning which little appears to- have been previously known. Although a complete account of the theory of the mechanism for mathematical purposes has been published in the ‘ Philosophical Trans- actions of the Royal Society’ (Part II. 1885), and a new machine exhibited: at the Inventions Exhibition has been described and illustrated (‘ Engi- neering,’ 1885), yet so much new work has been done in designing and testing the machines since made that the authors believe the following account of the results will prove of interest and value, especially as the question of friction gearing is one about which few facts are published, and much uncertainty exists as to proper proportions of surfaces in contact, dimensions of the various working parts, power transmitted, and. actual loss in its transmission. 1. Description or Macuines. In the first two machines made for the transmission of power, the weight. of the ball was utilised for obtaining pressure on the rolling surfaces. In one of these the driving and driven surfaces of the wheels were of cast iron; in the other oak was tried, which proved to be useless owing to its distortion, and secondly raw hide, which was found not sufficiently rigid for the pressures required. Neither machine was of any use, the efficiency being too small. Their failure was due both to the smallness of the pressures and the vibration set up, which latter kept tbe ball away from the wheels. The next machine! was designed so that any required pressure could be brought to bear on the rolling surfaces, and which, while trans- mitting considerable force, should not occupy much space. The diameter 1 For a full account with illustration see Engineering, Nov. 27,1885. This machine is now on loan at the South Kensington Museum. ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 485 of the hall was 6”. This machine was exhibited at the International Fies. 1 & 2. UID) JY | vos 1 H Tnventions Exhibition, where it successfully worked for several months, and gained a Gold Medal award. It was, however, fatally defective in 486 REPORT—1886. one respect, for there was no provision to prevent the ball from revolving whilst its axis of rotation passed through the point of contact made with the driven wheel. Figs. 1 and 2 show a hoist in which this defect was obviated, and which was designed so that the pressure on the driving and driven wheels. should vary with the load to be raised. This arrangement ensured a greater efficiency than could otherwise be obtained.' The framing of the hoist was made to bolt to a pair of vertical posts. A drum (m), which replaces the differential arrangement originally used, is carried on one end of a shaft (n), which by means of a wheel (A) placed at the centre of its. length receives the motion from the ball (0). The other end of the shaft is held in a bearing (p); and therefore, since there is no centre support for it except the ball, the pressure on the ball must be due to the con- stant weight (due to the shaft-wheel, &c.) plus the load multiplied by a constant quantity. The hoist is started, stopped, reversed, or has its speed changed by simply pulling one or other of two ropes which hang in a convenient position. This machine has worked most satisfactorily for more than half a year,. and has given no trouble. It works at present thoroughly well, and seems likely to last many years. Experimental data as to its efficiency are given hereafter. There is great difficulty in making the framing of these machines light and compact, and at the same time sufficiently rigid to withstand the- heavy pressures used. One chief source of difficulty is the part of the frame necessary to carry the pressure-wheel (fig. 1). Figs. 3 and 4 show a machine in which this wheel is dispensed with. Two balls are employed in contact with each other at the point (0). The driving-shaft (A) is of cast iron and is hollow, having two flanges, which at the points. (m ) press against the two balls. The drum (8) has also two correspond- ing flanges, which touch the balls at the points (17). The guide-wheels for each ball are moved simultaneously, so that the axes of the two balls move symmetrically ; hence for each ball there is always the same ratio between: the speeds of the surfaces at n, /, and 0; and since the speed at n is the same in each case, the other speeds must also respectively be equal, and therefore all the surfaces roll freely upon each other. This machine is extremely compact, and works well. It is now at the Liverpool Exhibition, and with two 6” balls transmits over 2 horse- power. 2. SpecraL DETaILs oF CONSTRUCTION. Mode of Preventing Injury to Sphere when its Axis of Rotation passes through a Point of Contact. The chief advantage of the sphere and roller mechanism is the power’ of varying the velocity ratio of the driving and driven wheels by the mere motion of a lever. As is fully set forth in the papers above referred to, this result is obtained by causing the axis of rotation of the sphere to assume different positions relatively to the driving and driven wheels. When, however, the latter is required to move at a very slow speed, or to actually come to rest, the axis of rotation passes so close to the driven wheel that the sphere spins upon the point of contact, and there is con- 1 This machine was briefly alluded to in the paper read before the British. Association, Aberdeen meeting, by Professor Hele Shaw. ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 487 siderable danger of flats being ground upon the surfaces in contact. This frequently occurred when the machine was running, and it there- Fie. 3. fore became absolutely necessary to devise some means to stop the machine when the axis was in the critical position. Fortunately it was found that Fic. 4. stopping the machine in that position had a great advantage, because it was impossible for the load to run down, the driven wheel being then 488 REPORT—1 886. unable to drive the sphere, and the only other way for the load to fall was by the wheel sliding over it. By arranging so that the machine should always stop at this point, and nowhere else, the danger to the ball was averted, a brake could be dispensed with, and starting and stopping easily arranged. The manner in which the difficulty was overcome is clearly shown in fig. 1. The rigid arm (a) connecting the two guide-wheel frames (q) has a lug cast on it. When the axis of the ball passes through the point c, the lug throws back the end (f) of the bell-crank lever (d), and thus, by means of a connecting rod and two other levers, throws up an arm (h), with a tooth on its freeend. This tooth engages in a thread of coarse pitch on the sliding part of the clutch (p). As the clutch revolves the screw draws out the sliding part, thus stopping the machine. When the machine is started the arm (a) is moved, the bell-crank lever returns to its former position, the tooth (h) falls away from the thread, and tbe spring (s) forces the clutch into gear, and the ball again revolves, but with its axis now in a safe position. There is the objection to this arrangement that only at one point of the reyolution of the clutch can the arm be moved so as to reverse the driven shaft, and this causes delay in working. In the hoist next made (figs. 3 and 4) a much better device is used, whereby it is only possible to stop the machine at one point of the revolu- tion of the driving-shaft, and thus there is little fear of stopping when it is desired to reverse the motion. If, however, the axes of the balls are left so as to pass through (11), not more than one or two revolutions can take place before they stop, and there is not sufficient time for any harm to be done. Referring to figs. 3 and 4, the handle (h) attached to the vertical shaft (k) controls the change of axes of the balls. When at the right position a nipple on the bell-crank lever (m) moves the lever (r), and lifts the end (z). Meanwhile the revolution of the driving-shaft brings the arm (s) against (z), (s) and the nut (d) thus cease to revolve, and the rod (q), being advanced through the nut, throws the clutch out of gear. On turn- ing the handle the arm is released, and the spring (s) moves the rod axially, and brings the clutch into gear. This arrangement answers per- fectly, allowing a free movement of the axes of the balls, with quick reversal of motion and change of speed. Bearings.—Great attention has necessarily been bestowed on the bearings, the following conditions being required :— (a) Diameter as small as possible, to reduce the loss in friction. (b) Such arrangements for lubrication as shall be as far as possible perfect. (c) Security from escape of lubricant on to the rolling surfaces. The conditions of working are unusually severe, and the bearings, which have been found to work satisfactorily, are therefore described in detail, and illustrated in figs. 5, 6, 7, 8, 9, and 10. Fig. 5 shows a bearing suitable for taking an oblique thrust. The part (f) is a portion of the framing of the machine. The bush (a) is of phosphor bronze, both the ends of the shaft (b) and set screw (c) have steel points, made as hard as possible, with a small hole drilled in the centre of each. Stauffer lubricant is introduced through the tube (h) into the inside space. ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 489 The bearing is first adjusted by means of the screw (d), which has a large flat head, forcing the busb (a) in, and taking up all the slack on the conical part of the bearing. The set screw (c) is next turned until it takes all the end thrust on the shaft (b). The bush is now locked by means of the set screw (p). This makes a very efficient though expensive bearing. Figs. 6 and 7 illustrate the manner in which an oil bath was applied to the bearings of the driving-shaft in fig. 8. The shaft in question works under a pressure of about 1,200 lbs., the size of the bearing being Fic. 6. Fic. 7. 3” diameter by 1}” wide, the surface speed of the journal being about 150 feet per minute. Referring to the figure, s is the shaft, a the cast- iron bearing, the surface of s is also cast iron. A light brass framing with leather lining is attached to the bearing (a) by the flanges (bb b), and makes a joint round the shaft at cece. The chamber e contains the oil. This bearing has worked continuously without heating, and gives most satisfactory results, the only defect being a slight leakage of oil round the flanges cc cc, fig. 7; the amount is, however, very small. It was designed from data given by Mr. Beauchamp Tower in his account 490 REPORT—1886. of experiments on oil-bath bearings, conducted for the Institution of Mechanical Engineers. Figs. 8 and 9 show the form of bearing used for the guide-wheels on the machine, fig. 3. They were adopted as the best of a number which were tried for the purpose. A fixed spindle (a) is secured to the frame (k) by the bolts (d). On (a) is a fixed collar (b), with a projecting rim (ee), and also a loose collar screwing on it witha similar rim (ee). These- Fie. 8. Fie. 9. rings fit into recesses turned in the wheel (hh); the bottoms of the- recesses are packed with leather rings (ff). It is obvious that on screwing up the collar (c), the rims on both sides of the wheel are forced into the leather, thus making a running joint, the oil having to escape past the leather before it can get out. This device answers fairly well, for the wheel (g) being hollow and filled with oil, perfect lubrication is ensured, although in this case also- a slight amount of oil escapes. Some experiments just made show that even the best of leathers are very porous and spongy, absorbing oil very readily, and when employed as a packing for bearings this material seems to act as a pumping appa- ratus, continually sending oil in the wrong direction. Leather is not therefore a safe material for packing a running joint against oil; and in spite of numerous tests, so far, no really suitable material has been found. Fig. 10 shows the arrangement of bearing adopted for the guide and pressure wheels on the machine at the Inventions Exhibition, 1885, and also on that shown in figs. 1 and 2. A steel spindle is keyed to the wheel b, and runs in bearings bored in the phosphor bronze, or cast-iron frame (/). Caps (cc) are screwed on (f), thus forcing the semi-lubricant. which fills (¢) and (d) into the bearing. Rings of packing (ee), made of strips of leather and cotton wick, are sufficient to prevent the escape of the lubricant at the running joint. These bearings run for months without requiring attention. ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 491 The Material and Construction of Spheres. The production of balls at a low cost, and yet suitable for standing the heavy pressures without excessive wear, has been one of the chief difficulties encountered. Fie. 10. p-==- MMM“ Se QGG WQUY ' 7 ‘ In first small models the balls were made of boxwood, lignum-vite, lvory, oak, gutta-percha, india-rubber, and brass, of which the last was most satisfactory. In the large machines, lead, mixtures of lead, zinc, and tin, cast iron, phosphor bronze, and hollow unhardened cast steel have been tried. Of these, hollow cast-iron balls have proved the best. With solid cast iron it seems almost impossible to get spheres quite free from flaws; as many as sixteen balls, cast by four different founders, only left, on turning up, two which were fairly good. But this material stands the wear and tear much better than was expected. In one case a hollow cast-iron ball 8’ diameter has been in frequent use in a 4-ton hoist (figs. 3 and 4) for eight months; careful callipering fails to show any loss in diameter. Unhardened cast steel is too soft. Hardened and ground cast steel and phosphor bronze are too expensive. . It might be mentioned here that, though with absolutely rigid material the surface of contact between the balls and the wheels would be reduced to a point, yet according to the pressure and material a considerable facet is formed. The amount by which the centre of the surface of contact is depressed is, however, extremely small. Thus in a 6” ball in contact with a plane surface this depression is only ‘0017” for a facet 1” diameter. 492 REPORT— 1886. Experience shows that the harder the material the less is the loss due to rolling friction, no greater normal pressure being required. Some ex- periments recently made show that two chilled iron spherical surfaces 6’ diameter rolling on each other give at about 1,500 lbs. normal pressure a coefficient of friction of over ‘25. For some time past experiments have been proceeding with the object of procuring perfectly sound chilled balls. So far not one has been obtained, though some twenty to thirty have been cast. 3. DATA DERIVED FROM EXPERIMENTS WITH SPHERE HOIST AND WITH SPECIAL APPARATUS, The hoist shown in figs. ] and 2 has been in daily use in the works of Mr. Edward Shaw at Bristol for more than six months. Two sets of experiments have recently been-made upon it, the results of which are given below (Tables I. and II.), and have also been plotted (Plate IX.). In both cases the driving-belt was replaced by a cord on which weights were hung, so that the force required to raise the load could be ascertained. The first set of experiments (Table I.) shows the forces required to overcome the friction of the machine, and raise the load from a position of rest. The second set of experiments shows the forces re- quired when the machine is in motion to lift the load at a constant speed. In both cases the efficiency of the machine has been worked out for every experiment in the following way :— Let W = load on hoist in lbs. P = weight hanging over the driving-pulley. distance moved through by P___ distance moved in same time by W V.R. = velocity ratio = ooo efficiency=y= )+V. R= TABLE I.—STATICAL RESISTANCE OF FRICTION. EXPERIMENTS ON SPHERE HOIST AT CANONS MARSH, BRISTOL, April 13, 1886. Weight of pan, 22 lbs. Diameter of small pulley, 83 in. Diameter of large pulley, 17 in. Fe driving ,, 133 in. | tag Position 1, V.R.=8 {Position 2, V.R.= 12} Position 3,V.R. = 24 [Position 4) | -%0.0f | Toad on oi Hoist W aes Weight=P Weight=P| 1» | Weight=P P 1 0 29 0 29 0 29 32 2 56 39 18 36 13 35 38 3 112 52 26 49 19 47 43 4 168 61 34 56 25 52 50 5 224 72 36 66 28 59 55 6 280 83 42 79 30 64 57 7 336 94 “44 85 33 vel 61 8 392 106 “45 95 34 77 64 7 448 119 AT 105 35 85 70 10 504 128 “49 112 37 89 74 11 560 140 5 122 39 98 78 12 616 153 “49 133 39 110 84 13 672 164 “BL 149 38 113 90 "Plate IX 2 CURVES PLOTTED FROM TABLE I. ‘SFAUND d “S3AUND YA 56" Report Brit. issn r 360 lbs. -EFFICIENCY Curves FROM Taat-e | Sra Ly Spoitiswoode kU? Lith, Lond —_ = ————7 56" Reporte Brit tesco 1886 "Plate IX a Fic | Curves PLOTTED FROM Taste | Bs Fic. 2Curves pLotrep From Taste Il 180 ali ] ] T TT 760) Cie T + oy Fe 40 a sy 2 + oO | baad 120) ey é | 3] 2 00! 100 > v c =) Oo wo mm a 2 @ 60) > yAl2t_-f---—| & i aber ae cA rs) a = ee = > a = 20 = SS o 500 550 600 660 00 lhs. wo 80320 © sea lbs. Fic le. ErFicieNcy Curves From Taste! Fic 2e Erriciency Curves FROM TAate | = He 10 + & 6 4 4 2 Oo 00 150 200 260 300 360 #00 460 600 660 600 660 700 lbs. 40 80 120 160 200 140 240 Tlastratony Profissor Hele Shaw and M’ Edward Shaws Paper on the Sphere and Roller Mechirasm tor Tunsrattony Power ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 493 TABLE II.— RESISTANCE OF FRICTION WHEN HOIST WAS RUNNING. EXPERIMENTS ON SPHERE HOIST MADE AT CANONS MARSH, May 10, 1886. Load lifted direct from barrel, 5} in. diameter. N Position 1, V.R.=4 | Position 2, V.R.=6-4 Position 3, V.R.=12 0. of | Load on Experi- Huis u = a aerit oist W Weight=P u] Weight=P 7 Weight=P v7) 1 0 14 0 14 0 14 0 2 56 42 385 30 293 24 2 3 112 50 566 38 467 30 317 4 168 66 641 52 “509 39 364 5 224 80 704 63 560 47 401 6 280 96 733 72 612 54 436 7 336 — — 88 “60 63 448 The different positions of the lever of the hoist in the above experi- ments, resulting in different velocity ratios, are easily understood from the tables, with the exception of the position 4 (Table 1.), which was the position when the velocity ratio was as great as it could be made, this being the limiting position in which the load could be raised. The above tables of results are plotted as curves on Plate IX., the loads raised being measured (in lbs.) as abscisse in all the four figures. The dotted lines in figs. 1 and 2 show the velocity-ratio curves, points on which are obtained by setting up as ordinates the forces theoretically required for various loads, supposing no loss in friction to take place. The three cases of velocity-ratio are respectively numbered 1, 2, and 3, and all the dotted lines representing them necessarily pass through the origin of co-ordinates. The centres of the small circles are points obtained by setting up as ordinates the forces actually required. The results are not perfectly regular, but the irregularity obviously arises from the difficulty of conducting such experiments with very great accuracy, although every care was taken to obtain trustworthy results. It is, however, not difficult to see that the curves which practically represent the results are straight lines drawn in full on figs. 1 and 2. Although in the first set of experiments these lines all pass through one point, showing that the friction of the machine when starting from rest is independent of the velocity-ratio, yet they do not in either set of experi- ments pass through the origin, since this could only occur for the case of a frictionless machine. Thus the equations representing the curves are— (1) For velocity-ratio, y=me. (2) For actual results of experiment, y=nz +c, where m, n, and c are constants which can easily be obtained. The curves in figs. 1H and 2K are those of efficiency obtained by plotting the corresponding results given in Tables I. and II., the equa- tions of the various efficiency curves being of:the form me. 1 ne te and since y=0 when #=0, they evidently all pass through the origin. 494 REPORT—1 886. Eaperiments with Special Apparatus. In designing the sphere and roller machines it was assumed that between the rolling surfaces the coefficient of friction was u=0'1, and consequently that the pressure required between the ball and the disc must be ten times as great as the force to be transmitted. During the experiments above recorded it was found that the coefficient of fric- tion was not constant, but increased with the pressures, the highest value being about The machine at the Liverpool Exhibition gave results even higher than this, and, generally speaking, it has been observed that the value of the coefficient at the high pressures used increases slightly with the pres- sure. It is evident that the circumstances of the case are peculiar, and that even the few published experiments upon rolling friction—such as those upon locomotive tyres—did not furnish satisfactory data for guid- ance. It was therefore determined to conduct a series of experiments with special apparatus, and for this purpose the machine shown in figs.11] and 12 Fies. 11 & 12. was designed. This apparatus consists of two discs (a) and (b), six inches in diameter, the edges of which are in contact, and which can be replaced by other similar dises of different material. One of these discs (a) is driven TRANSMITTED FORCE tyeet Brat Ans 1586 Fic.3 CURVES PLOTTED FROM [ABLE Ill Z ag Pee corp qenea ale ar ne IL | im JE 7 | LL ial | y 4 ON SPHERI directly from by friction at toa dynamo of a lever © the point of | {1 and Kk), end of the le acts by mean at the lower disc (b), and forces betwe just twenty- o 220|__| T j ee | + | | "The resis E 7 | | (a) The | wo +4 : { (n) The | | alt IL} | (c) The + eit | ial 4 7 | | | lel ‘The first 180) 1 / r 1 esd atten heme | ; - ia the belt was | \ y, / 1 t ee the wheels § | i tees | i | me s ate || ances Was SU | | } ye point. ‘Thu R a! | | {c) could be + +4 +—| _|80 Ths the forces tr 40 J| | OA of | Three se } (i) Cast el Gi.) Css 120 “Ve Git) Ob } | The resu | By { TABLE II1— 100 g | 9 a0 if ° ae 60 ° 4 nae se a | 400 500 i Jo 200 300 600 700 800 900 1000 00 J200 1300 1400 1500 1600 zoo s400 lbs 1 Hele Shaw and WM” Edwurd Shaws Paper on the Sphere anil Roller Mechurasm tor Gransmating Power —_— [_ er 5 ON SPHERE AND ROLLER MECHANISM FOR TRANSMITTING POWER. 495 -directly from a motor by means of a pulley (p), the other (b) being driven by friction at their point of contact. The latter disc is connected directly to a dynamometer brake (c), the resistance of which is shown by means of a lever (e) and arod(f). At the same time the normal pressure at the point of contact (d) is measured by means of a combination of levers ({u andk). These levers act thus. A weight (w) being hung upon the end of . the lever (1), which has its fulcrum at the top of the support (J), acts by means of a link (/) upon a second lever (#), which has its falerum at the lower end. The lever (k) carries the bearings of the shaft of the disc (6), and thus the weight (w) is an exact measure of the horizontal forces between the discs, the leverage being such as to make this latter just twenty-one times as great as the weight in question. The resistance overcome by the belt was threefold :— (A) The brake friction. (8) The bearing ,, (c) The rolling ,, The first only of these could be accurately determined, the sum of the others bemg estimated in the following way. Up to a certain point the belt was powerful enough to overcome all the friction and to make the wheels skid over each other, but beyond that the sum of the resist- ances was sufficient to make the belt slip, which it did at a fairly constant point. Thus for a definite increase of pressure the increase of (B) and (¢) could be determined by the diminished reading of (A). By this means the forces transmitted to the driven wheel were approximately estimated. Three sets of experiments were made :— (i.) Cast-iron discs with flat faces, 3, in. wide. (ii.) Cast-iron discs with flat faces, ;1; in. wide. (iii.) Chilled cast-iron dises with spherical faces ground true. The results of these experiments are given in the following Table III. TABLE III.—ReEsvuLts oF EXPERIMENTS WITH SPECIAL APPARATUS FOR TESTING THE FORCES TRANSMITTED BY ROLLING CONTACT. No. 1. No. 2. No. 3. Cast-iron wheels Cast-iron wheels Chilled iron wheels Flat faces ,3; in. wide Flat faces 3; in. wide Spherical faces ground true Se | A 4.3 & & as | ees) ee| ge we | 284 we | 22a 2 Fl aos IB g as 6 * | Remarks Jeu | = fs = | Remarks | ‘2 he S27 | Remarks mH | SoH AS | SES as | 8Be ae | ee oa | gga Ba) oge | Bee i = Bo id = lag aos Bo 15 315 10 45 Wheels skidf 12 51 Wheelsskidf 14 57 Wheels skid 20 420 | 13 59 ui 17 70 - 20 79 A 25 525 19 81 on 24 96 Ze 27 105 - 30 680 | 25 | 105 es 32 | 194 a 34 | 130 fe 35 735 30 125 a 38 146 - 42 158 os 40 840 37 149 a 44 161 5 56 186 A 45 945 | 43 172 Do. and 51 195 - 70 | 248 * Belt slipped Do. and 50 1050 45 rr 6 215 4 75 268 Belt slipped 55 | 1155 | 41 Belt slipped] 62 | 237 35 75 ee 60 1260 37 _ 67 258 fh 70 Belt slipped 65 1365 | 33 3 71 | 272 : 66 Ss 70 | 1470 | 30 re 68 Belt slipped} 65 pe 75 | 1575 | 28 ‘ 65 63 is 80 1680 26 = 62 60 ae 85 | 1785 | 24 i 60 60 3 496 REPORT— 1886. The above results are plotted in the form of curves (Plate X.), the pressures between the surfaces being taken as abscisse, the correspond- ing forces transmitted as ordinates. From these curves it is clearly seen that by reducing the area of the surface in contact a less pressure is required to transmit a given force; thus the curves 1, 2, and 3 rise above each other in regular order (3 being the curve corresponding to the chilled iron spherical surfaces); and, moreover, that while the two first are straight lines the last rises more rapidly as the pressure increases, and, in fact, gives at last a coefficient of friction Finally it may be remarked that, whereas at lower pressures and with larger surfaces in contact the presence of oil upon the latter causes con- siderable variations in frictional resistance, it was found that at the highest pressures used in the last set of experiments oi) poured continuously upon the rolling surfaces had no appreciable effect whatever. On Improvements in Electric Safety Lamps. By J. Wiuson Swan, M.A. [A communication ordered by the General Committee to be printed in extenso among the Reports. | I sHowep an Electric Safety Lamp in this Section last year. I have now improved the lamp in various ways, and I propose to describe and exhibit the improvements. The objects I had in view in altering the original design were :— 1st. To reduce the weight as much as possible consistently with the giving of sufficient light. 2nd. To simplify the construction, with a view to minimising the cost of manufacture and the cost of keeping in order. 3rd. To make the lamp better able to resist a blow. Ath. To seal in the liquid, so that the lamp could be held in any position. 5th. To add a fire-damp indicator. The lamps on the table embody these improvements, and are here for the inspection of members. , The details of construction and the record of experiments are given in the diagram. With regard to the first point—namely, the size and weight of the apparatus—that, of course, depends, in a great degree, on the amount and duration of the light. Guided by the fact that the best of the oil safety lamps scarcely gives the light of one standard candle, and that most of those in common use give only a quarter or half a candle, I have assumed that an average light of one candle, over 12 hours for datal men, and 11 candle over 9 hours for hewers, is sufficient, and I have fixed the size of the battery in the new lamps on this assumption. No alteration of the design is necessary when more or less light than this is required, but merely an increase or decrease of the size and weight of the battery contained within the lamp body. ON IMPROVEMENTS IN ELECTRIC SAFETY LAMPS. 497 In this respect the Hlectric Safety Lamp has a marked advantage over all safety lamps of the ordinary kind, which depend on the combus- tion of oil; they cannot be made to give a much larger light without radical alteration, if at all. If the Electric Safety Lamp is required to give 5 or even 10 candle-light, it is only necessary to proportionally in- crease the size and weight of the battery. Safety is not in the slightest degree impaired. There is nothing easier than to be deceived as to the amount of light that can be obtained from a certain size and kind of battery applied to an incandescent lamp. Ifthe lamp is constructed so as to allow such a large current to pass through the carbon filament as will heat it to the enormously high temperature at which disintegration rapidly takes place, ten times as much light is produced as when, by the use of a different lamp, the current is diminished, and the temperature of the filament thereby lowered to a degree which will prolong the life of the lamp to an economical point. In the case of a miner’s safety lamp, it is very desirable to get as much light as possible from a given weight of battery, and hence it is allowable to sabject the lamp filament to what may be termed a rather high pressure, but not such a high pressure as will prevent the lamp from lasting about 700 hours. Subject to this condition I find I can obtain an average light of one standard candle during 12 hours, and 14 candle during 9 hours, from a battery, which, with all the appurtenances of the lamp attached to it, weighs altogether 5} lbs. The same battery, with a different lamp filament, will, of course, give either more light for a shorter time, or less light for a longer time than that I have mentioned. The battery cells are slightly different in construction from those in last year’s lamp. They consist, as before, of a central solid cylinder of peroxide of lead, with a conducting core of lead wire, fixed concentrically, by means of guide rings of india-rubber, within a tube of lead, the in- ternal surface of which is in the spongy state. The annular space between the peroxide of lead cylinder and the lead tube is filled with dilute sulphuric acid. Four such elements are fitted into four ebonite lined holes in a block of wood saturated with paraffin. The lead wire connections between cell and cell are covered with india-rubber, and embedded in channels in the wood, and covered with Chatterton’s com- pound. Over the buried connecting wires is fixed a veneer of ebonite, which farther protects them, and also forms a level seat for the cushion of india-rubber, which, when pressed down by the cover-disc makes the cells liquid-tight, so that the whole block may be laid on its side, or in- verted, without leakage. In the form of lamp I showed last year the cover of the case which contained the battery had to be screwed off to get at the battery terminals, for the purpose of putting them in connection with the charg- ing circuit. In the new design the removal of the cover is avoided by bringing down the battery terminals to the bottom. Access is given to these through two small holes, within which fit two pins connected with the positive and negative charging wires. Charging is effected by simply placing the lamp on a bench fitted with charging pins, in connection with wires from a dynamo, so that the charging pins enter the two holes at the bottom of the lamp case. The lamps remain on the dynamo cir- cuit, receiving their charge during the time the men who have used the K K 498 REPORT—1886. lamps are resting, and they become fully charged by the time these men return to work. It is a point in favour of this kind of lamp that the operation of re- newing the charge is effected with little trouble and cost—far less than is involved in replenishing and cleaning ordinary safety lamps. For example: one horse power is sufficient to charge one hundred lamps at a time; that item of cost will, therefore, not exceed a farthing a lamp per week. The total cost will not exceed fivepence per week, where several hun- dred lamps are in constant use. That amount will, I estimate, cover the total weekly cost per lamp, including renewal of lamp-bulbs, the cost of fuel, wages for keeping the lamps charged and in repair, and interest at ten per cent. on the capital outlay for the whole plant, including the lamps themselves. In one of the modifications of the lamp the light is fixed upon the top of the case, with a view to the illumination of the roof and sides of the mine. This form of lamp is intended for the use of over-men while travelling in the workings. The bull’s-eye form, with the light on one side, is intended for the use of the hewer. While the hewer is at work the lamp will be hung up on a hook as usual. Where low workings have to be traversed the lamps can be fastened to the breast of the miner by a strap across the shoulder. The only other point requiring explanation is the fire-damp indicator. The want in the lamp I showed last year, of the means of showing the presence of fire-damp, was urged as an objection to it. I have met the objection by adding an indicator. This will not be required on every lamp, but only on lamps used by over-men. I have made the indicator in three forms; two of these act on the same principle as Liveing’s fire- damp indicator. A spiral coil of thin platinum wire is arranged so that it can be heated to a low red heat by switching through it the current generated by the lamp battery. If this takes place in an atmosphere in which fire-damp is present, the wire becomes hotter than when heated in pure atmospheric air, because combustion of the fire-damp with the oxygen of the air, brought about by the electrically heated wire, produces additional heat, and, consequently, increases the temperature of the wire, so that it is sensibly brighter whan heated in air containing fire-damp than when heated in air in which there is no fire-damp. In one form of the indicator I have followed Mr. Liveing’s idea of having a comparison wire, shut up, air-tight, in a glass tube containing pure air. In another I have deviated from Liveing’s construction in two ways ; namely, by having only one wire (the test wire), and instead of this being in a wire gauze cage, always exposed to the atmosphere in which the lamp is placed, it is in a tube which, when the current is turned on to heat the wire, is completely closed. Jt is not easily con- ceivable, even if the test were made in an atmosphere of air and fire-damp of maximum explosiveness, that flame would pass the fourfold lining of fine copper wire gauze of the Liveing indicator; still it is, perhaps, more consistent with the absolute safety of the lamp itself to make the test in a closed vessel. With the double wire arrangement, when fire-damp is present in the air, even in so small a proportion as half a per cent., the exposed wire glows with perceptibly greater brightness than the enclosed ON IMPROVEMENTS IN ELECTRIC SAFETY LAMPS. 499 comparison wire. With the single wire arrangement, under the same atmospheric conditions, the wire would glow for an instant with extra brightness, and then, after the small quantity of enclosed fire-damp is consumed, would die down to normal redness. The third form of indicator acts upon a different principle. In it there is a platinum wire within a small tube, and the means of turning on the current from the iamp battery to heat the wire, as before ; but here the hot wire is employed only to effect the combustion of any fire-damp that may be present, with a view to the production of a partial vacuum resulting from the condensation of the watery vapour of the burnt gases. The degree of vacuum or shrinkage is shown by the rise of liquid in an adjacent gauge-tube, and from this the exact percentage of fire-damp present in the air may be ascertained. This form of test is also, and necessarily, made in a closed vessel. The hot wire is completely cut off from contact with the outer air. I think it will appear to the Section that I have produced a miner’s lamp having the advantage of absolute safety, and which is, at once, more efficient and more economical than any other miner’s lamp yet con- structed. On the Birmingham, Tame, and Rea District Drainage. By Wiu1aM Tr. |A communication ordered by the General Committee to be printed in eatenso among the Reports. ] Tue author in submitting this paper begs to state that he has not entered into any discussion of the relative merits of the various systems of sewage purification now in operation, nor has he advanced any theory of his own in relation thereto, but has confined himself to a practical and historical account of the work of the Birmingham, Tame, and Rea District Drainage Board, merely adding from time to time such remarks as seemed needful for the proper explanation of the subject under consideration. In giving an account of the formation and work of the Drainage Board, the works of sewage purification previously undertaken by the Corporation of Birmingham form so important a part that any general description of the Drainage Board would be incomplete without some reference thereto; but inasmuch as the efforts of the Birmingham Cor- poration to deal with the sewage difficulty have been so prominently before the various bodies interested in sanitary work, both from the pro- ceedings in Parliament and from several published statements, it has not been thought necessary to make further allusion thereto than may be required for giving a complete history of the position and work of the Board. ' It may perhaps be desirable to glance briefly, in the first instance, at the sanitary condition of the district generally prior to the formation of the Board, with a view of setting forth more clearly the advantages the various authorities now comprising the Board were intended to derive from their union. The borough of Birmingham, together with the towns of Walsall, West KK2 500 REPORT—1 886. Bromwich, Wednesbury, Darlaston, Tipton, part of Wolverhampton, and a number of other urban or rural sanitary districts, forming the major part of what is known as the ‘ Black Country,’ is situated near the summit of one of the great watersheds of England—that of the Trent—being drained by the River Tame, which, with its various feeders, forms a small stream, discharging into the Trent about midway between Tamworth and Burton. Whatever may have been the benefits derived by the large pypulation of the Black Country from being situated high up in the watershed, one great disadvantage—that of sewage pollution—gsoon became apparent owing to the naturally diminutive character of the watercourses and the large amount of liquid refuse poured into them. The Corporation of Birmingham, as the principal local authority, was early made aware of the responsibility thus incurred, and was earnestly combating the sewage difficulty at a time when the authorities of many towns considered it, if not exactly the right thing to do, at any rate only a venial offence, to discharge their sewage into the rivers or streams that flowed in their vicinity. At the time the formation of the Drainage Board was suggested none of the authorities of the towns or districts draining into the Tame had made, so far as the author is aware, any really systematic attempt at sewage purification except those of Birmingham and Wolverhampton. The Corporation of Birmingham constructed, as far back as 1853, two main intercepting sewers whereby the sewage from those portions of the borough draining to the River Rea and Hockley Brook was conveyed to the general outlet at Saltley, where subsequently a system of tank purification had been adopted, and which was developed from time to time, until at the period when the Drainage Board was formed the Cor- poration possessed land and works thoroughly capable of purifying, so far as precipitation by lime could purify, the sewage of the borough. The Manor of Aston Local Board had caused plans to be prepared in 1874 for the intercepting sewers for diverting the sewage of its district from the River Tame and the Hockley Brook, and by agreement the Handsworth Local Board, whose district is situated on the same watersheds but higher up, became joint owners of such sewers. These sewers were con- structed in 1876, and although the sewage was thus diverted in detail it was only to cast it into the Tame again in one united volume, pending the decision of these boards as to the method of sewage treatment to be adopted; a problem that threatened to be very difficult of solution had not the Drainage Board about that time been formed, and so relieved those authorities of further trouble. The authorities of the district of Balsall Heath, a small but somewhat thickly inhabited area draining to the Rivers Rea and Cole immediately above the Borough of Birmingham, had esta- blished some precipitating ‘works of an elementary character at the outlet in the River Cole area, but owing to the great increase of population all around the use of these works had become objectionable, and as the only outlets for this district lay through the Borough of Birmingham, it became necessary, if great expense were to be avoided, that some arrangement should be made for the Corporation to provide the requisite outlets. The district of Harborne, likewise situated in the watershed of the Rea above the Borough of Birmingham, had also established a system of tank purifi- cation, but open to similar objections to those above named in Balsall Heath, this district also suffering from precisely the same difficulties as to outlet. These, then, were the only districts in the neighbourhood of ON THE BIRMINGHAM, TAME, AND REA DISTRICT DRAINAGE. SOL Birmingham of which the authorities had made any efforts to deal with their sewage, whilst on the other hand there were several districts urgently in need of sanitary reform that had been unable, owing to their positions in relation to other districts, to take independently the necessary step except at a prohibitive cost. Birmingham and its sewage farm holding by virtue of its position the key of the situation, and the Corporation anticipating that great ex- pense and inconvenience must ultimately arise if some united action were not taken, it was decided to apply to the Local Government Board, under the Public Health Act, 1875, for an order to form the following urban and rural sanitary districts or portions of them into a united district for the purpose of sewage disposal, viz., the Borough of Birmingham, the Local Government Districts of Aston Manor, Handsworth, Smethwick, Balsall Heath, Harborne, and Saltley ; the contributory places of Aston, King’s Norton and Northfield, and Perry Barr; and portions of the districts of the West Bromwich Improvement Commissioners, and of the Solihull Rural Sanitary Authority ; the principle of selection adopted being to choose only those districts lying round Birmingham which were restricted in their outlets, or which had no reasonable facilities for establishing purification works of their own. An inquiry lasting several days was held by J. T. Harrison, Esq., the Government Inspector, at the Public Offices, Birmingham, in which the West Bromwich Commissioners proved to the Inspector’s satisfaction that they were in a position to establish their own purification works, and the Rural Sanitary Authority of Solihull, having also recently prepared a scheme, was likewise omitted by the Inspector. All the other districts were formed into a united district, under the title of the Birminglium, Tame, and Rea Main Sewerage District, the Pro- visional Order coming into operation on September 29, 1877. The Joint Board consisted at first of twenty elective members, chosen from the members of the various constituent authorities, of which the Borough of Birmingham sent eleven and the others one each ; and two ex-officio members, viz., the Mayor of Birmingham and the Chairman of the Aston Manor Local Board. The district was enlarged in 1881 by the addition of the parish of Sutton Coldfield, but no alteration was made in the constitution of the Board until Sutton Coldfield was incorporated early in the present year, when the number of members was increased to 24, Sutton Coldfield sending one member and the representation of the borough being increased to the same extent. The first meeting of the Board was held December 6, 1877, when Mr. Alderman Avery, a gentleman well known in connection with the sanitary work of the Borough of Birmingham, was elected Chairman, a position he still occupies. The duties of the Board are the acquiring of such lands and the con- struction and maintenance of such outfall works as may be necessary for the purification of the sewage of the various constituent authorities, so that it may be discharged into any streams or watercourses without breach of the Rivers Pollution Act, 1876. It is incumbent on each of the con- stituent authorities either to construct such intercepting sewers as may be required for conveying the sewage of its district to the outfall works, or otherwise to arrange terms with one or other of the constituent authorities for the user of such sewers as may be necessary for that purpose. The Joint Board exercises supervision over the size, character, and direction 502 : REPORT—1886. of new intercepting sewers, so that they may be laid down with general! reference to the requirements of the united district at large, and in the case of its being desirable that one constituent authority should use the exist- ing intercepting sewers of another constituent authority, it devolves on the Joint Board to say whether such sewer can and ought to be so used to the extent of, but not exceeding, 40 gallons per head per day of the popula- tion of the district. The costs of the Joint Board are divided into the costs of management and the costs of outfall works (outfall works being the land, tanks, and works for purifying the sewage). All the constituent authorities, with the exception of Perry Barr, are liable to the costs of management, but no constituent authority is lable to the expenses of outfall works until some portion of such authority’s district has been placed in connection with ary of the said outfall works. The various districts contribute to the expenses of the Board in pro- portion to the number of rated tenements in each district or contributory place, such number being ascertained from the poor-rate made last before the times for issuing the Board’s precepts. The total area of the drainage district is 47,275 acres ; the population in 1885 was estimated at 619,693; and the ratable value 2,401,093/. Appendix A gives a detailed statement of the area, population, and ratable value. In accordance with the Provisional Order, the Drainage Board pur- chased as going concerns all existing lands and works for treatment of sewage owned by the various constituent authorities, such being Birming- ham, Aston Manor, Harborne, and Balsall Heath. Of these the works at Harborne and Balsall Heath were abandoned as soon as arrangements for outlets had been carried into effect, and the sites of such works were ultimately sold. From the Borough of Birmingham the Board acquired about 159 acres of freehold and 1034 acres of leasehold land, together with the extensive system of tanks, machinery, plant, farm implements, and stock situated at the general outlet at Saltley; and from Aston Manor about six acres of land, also situated at Saltley and surrounded by the Corporation farm. As the outlet at Saltley is the natural point of discharge for fully nine-tenths of the total population of the Drainage District, one of the first cares of the Drainage Board after its formation was to assist the various constituent authorities in their endeavours to put themselves in communication with the outfall works purchased from the Birmingham Corporation. Accordingly arrangements were speedily made for the Corporation to receive into their main sewers the sewage from the districts of Harborne and Balsall Heath, on payment of an annual sum for user ;. the Manor of Aston Local Board entered into a contract for the construc- tion of the sewer for conveying its sewage from the temporary outlet into the Tame to the Board’s tanks, the Aston Rural Sanitary Authority be- coming joint owner with Aston Manor and Handsworth, and thereby procuring an outlet for the Erdington and Witton portions of its district ; the Handsworth Local Board extended one of the Aston and Handsworth joint sewers, so as to accommodate the northern portion of its district, and has since, in conjunction with Smethwick, extended the other joint sewer, thereby completing for the present the intercepting sewers of its own district and providing for Smethwick an outlet for the larger portion of that district. The Saltley Local Board constructed the inter- ON THE BIRMINGHAM, TAME, AND REA DISTRICT DRAINAGE. 503 cepting sewers, and the Rural Sanitary Authority of King’s Norton, after arranging with the Corporation of Birmingham for an outlet through their main sewer, constructed the intercepting sewers for the drainage of portions of its district. For those portions of the Drainage District that could not conveniently be brought down to the common outlet at Saltley, the Corporation of Birmingham constructed the sewer for accommodating the area draining to the Cole comprised in the districts of Birmingham, Balsall Heath, King’s Norton, and Aston Rural, this sewer being tun- nelled across the ridge dividing the watersheds of the Tame and Cole, and discharging on to the new farm. The Aston Rural Sanitary Autho- rity constructed the sewer for the drainage of Sutton Coldfield, this sewer also discharging on to the new farm. As the result of the intercepting works just described, the whole of the populated areas of the Drainage District, with one exception, are now placed in communication with the outfall works. The one exception is the district of Smethwick, which, being situated at the summit of the watershed, has had to await the development of the intercepting system ; _ but it is believed that arrangements are contemplated whereby this diffi- culty will be shortly removed. j In the meantime, pending the completion of these intercepting arrangements, the Drainage Board had been proceeding with the very important duty of extending its outfall works so as to meet efficiently the additional strain that would in due course be brought uponthem. It had been generally understood at the time the Board was formed that an extension of the outfall works would be necessary, and after due consider- ation it was decided that the application of the sewage to land after partial treatment by lime, and in the tanks, would be the most satisfactory method of purification. The Board accordingly directed its attention to the acquisition of the required area of land. An opportunity that pre- sented itself in 1880 of obtaining the unexpired term of 102 years of a lease of 96 acres of suitable land at Tyburn, about 24 miles below the existing tanks, was embraced, and shortly after a lease for 99 years of 123 acres of adjoining land was obtained, while 250 acres of freehold from the Right Honourable the Earl of Bradford, 350 acres from the trustees of W. W. Bagot, Hsq., and 118 acres from various other owners were acquired by mutual arrangement, and more recently a further plot of 185 acres has been leased from the Right Honourable Lord Norton for 21 years, thus making a total of 9554 acres of additional land, or, including the land already occupied by the Board at Saltley, a total area of 1,227 acres available for works of sewage disposal. The rent of the leasehold land is at the rate of 4/. per acre, and the average cost of the freehold, including timber, buildings, mill rights, tenants’ compensation, law charges, &c., 1521. per acre. The nature of the land is very favourable for the purification of sewage, the natural surface of the ground being, as a rule, even and unbroken, and the level such as to admit of the irrigation of the whole by gravitation, with the exception of about 100 acres. The subsoil is gravel and sand, varying from 6 feet to 10 feet in thickness. To reduce the risk of flooding from the river the Board removed the mills and weir, and straightened the river at Minworth at the lower end of the farm lands, thereby lowering the water-level of the river several feet, and by the construction of outfall cuts, carried to suitable outlets into the river, the subsoil drains are placed beyond the influence of backwater, the result being that no inconvenience 504 REPORT— 1886. is experienced from the proximity of the river, except during unusual floods. For conveying the sewage to the land a conduit 8 feet in diameter and about 22 miles long has been constructed, capable of discharging 38 million gallons per day when running half-full, or double that quantity running full, the fall being 2 feet per mile. This conduit commences at the outlet end of the large tanks at Saltley and terminates at Tyburn, valves being placed at suitable intervals for discharging the sewage on to the land passed through. Below Tyburn the capacity of the conduit has been reduced, a conduit 3 feet 6 in. in diameter being sufficient for the remainder of the farm. The sewage is drawn from these conduits into open brick carriers, which again discharge into secondary carriers of earth, and thence into the flooding carriers. The brick carriers are con- structed with a slight fall, steps being provided in the inverts at suitable intervals for drawing down the water. The land is drained to a minimum depth of 4 feet 6 in., but in many cases, owing to the levelnature of some of the land, a greater depth has been found necessary at the lower ends of the drains. The subsoil drainage consists of 3-in. and 4-in. agricul- tural drain-pipes placed from 5 to # of a chain apart, and discharging into main drains of 9-in., 12-in., 15-in., and 18-inch stoneware socket pipes, which in turn discharge into the outfall channels. Roads generally 12 feet wide, with passing places at intervals, have been laid out with the view of meeting the requirements of the steam cultivating operations as well as for the conveyance of produce. In addition to the farm buildings at Saltley, purchased from the Corporation, farm buildings in a central position at Tyburn have been erected, together with entrance lodge, manager’s house, and six labourers’ cottages; also smaller buildings at Minworth and four labourers’ cottages. The various farmhouses and buildings originally existing have also been repaired and extended. The totai cost of the land and works to the present has been 403,6951., of which the purchase of original land and works is 170,544/., new land 110,8007., new works 113,299/., farming stock and implements for new land 9,052. The details of cost are given iu Appendix B. The method of treating the sewage as now carried on is as follows :— The sewage on arriving near the liming sheds at the upper end of the works is mixed with lime, both to neutralise the acids (present to an unusual extent in Birmingham sewage) and also to assist precipitation, which, however, is not now necessary to so great an extent as formerly ; the sewage then passes through the large or roughing tanks, where the grosser impurities are precipitated, and thence it is conveyed by the main conduit to the land and disposed of by ordinary irrigation. The sixteen small tanks required at one time for completing the precipitation process are still used under certain circumstances, and are a valuable auxiliary when rainfall has increased the normal quantity of sewage. The sludge from the tanks is elevated by bucket dredgers and pumps into movable wooden carriers, and flows into beds formed in the land at the Saltley or western end of the farm. The sludge contains about 90 per cent. of water as it comes from the tanks, but after lying on the ground for about fourteen days much of this water drains away or is evaporated, leaving the sludge in a layer about 10 inches thick and of a consistency that admits of its being trenched into the land. Crops are then planted, and after a time the sludge becomes pulverised and capable of being irrigated. About forty acres of land were required for the ON THE BIRMINGHAM, TAME, AND REA DISTRICT DRAINAGE. 4505 sludge last year, and the same land may receive a coating of sludge every two to three years. A few words may be said as to the difficulty at one time experienced in dealing with the mud from the tanks. After the construction of the first two large tanks in 1859 the mud therein deposited was dredged out and run on to the adjacent land, where it accumulated for some years, forming at one time a large mass of foul matter about seven acres in area and over four feet deep. In consequence of the nuisance arising therefrom proceedings were taken, about 1871, by the residents in the vicinity, and an injunction obtained restraining the Corporation from depositing the mud so as to cause a nuisance. Great efforts were made by the Corporation to reduce the amount of mud, large quantities being conveyed away in boats, but it was not until the experiment had been tried of trenching the mud into the land, and found perfectly satisfactory, that the present system was adopted, about the end of 1872, and the difficulty finally overcome. Practically the whole of the sewage of the Drainage District, amount- ing to sixteen million gallons per day, flows by gravitation to the outfall works. Only a very small area requires its sewage lifted by pumping, the -cost of such pumping being 104/. per annum. The Board farms the whole of the land, no portion of it being sub-let. Of the produce milk is a large and increasing item, 128,995 gallons, realising 4,406/., being sold last year. During the present year about 280 acres of land are devoted to mangolds, swedes, and kohl rabi; 250 acres to market garden produce, 100 acres to Italian rye grass, 130 acres to cereals, and about 340 acres are pasture. The total amount realised last year from the sale of stock and produce oe 20,0087. During the same time stock was purchased to the extent of , 7601. With regard to the financial aspect of the Board’s work it is perhaps needless to say that a considerable sum of money has annually to be obtained from the rates. The total amount raised by the Board’s precept last year was 33,089/., of which interest and repayment of loans absorbed 17,5161.; management expenses, rent, rates, taxes, &c., 5,5941.; the balance of 9,979/. representing the loss on the year’s working of the farm. Appendix C is a detailed statement of the actual income and expendi- ture of the farm and works during 1885. The great loss, as will be seen from the statement, is in the work at the outlet (which comprises the lime, wages, machinery expenses, and other charges connected with inter- cepting and dealing with the mud from the tanks). The amount ex- ended under this head (exclusive of rent) was 10,715/., for which sum 4,778 tons of lime were provided for precipitation, and 135,476 cube yards of mud were arrested in the tanks and dug into the land ; the corre- sponding income is practically mil. Since the opening out of the irriga- tion land the expenses at the outlet have undergone some reduction, and there is every prospect not only of a further reduction in the future, but also of a gradual increase in the receipts from the irrigation land as the demand for the farm produce is developed ; but bearing in mind the large initial outlay in purchase of land and the construction of works, and the -annual working expenses in disposing of so large a volume of sewage, it 506 REPORT—1886. is not to be expected that assistance from the rates can be dispensed with, until, in the somewhat distant future, the large annual sum now required for interest and repayment of loans shall cease. It should, however, be: remembered in dealing with sewage farm accounts that after all the great item on the credit side of the balance-sheet (although it is one that cannot be represented by a money value) is the satisfactory disposal of the sewage. In conclusion, it is only fair to observe, with reference to remarks. made in the first part of this paper as to the sanitary condition of the Tame Valley, that since the date then referred to considerable progress has been made in sewage purification, Walsall, West Bromwich, Wednes-- bury, Darlaston, and other towns and places having taken up the question. in a practical and energetic manner. APPENDIX A. Estimated Name of District Area in Acres | Population in Bei alg 1885 an £ Borough of Birmingham . 5 “ 8,420 427,769 1,621,701 Smethwick, Local Government District of : “1 1,882 26,000 113,667 Harborne ky 7 5 A 1,412 7,422 31,334 Balsall Heath ,, x “ 4 3 453 25,300 69,803 Saltley cn = 5 : : 1,039 7,100 47,514 Aston Manor ,, ES 5 3 : 943 62,510 171,875 Handsworth ,, ‘ F 3,638 27,300 (125,601 Aston Union, Contributory Place of Aston . 8,916 10,552 63,198 King’s Ni orton Union, Contributory Places of 3,500 15,275 84,476 King’s Norton and Northfield West Bromwich Union, Contributory Place of 4,042 1,655 19,208 Perry Barr Borough of Sutton Coldfield . : 4 5 " 15,030 8,810 52,716 Total a Tiewe « brtdotageet . lee ctyx 47,275 619,693 2,401,093 APPENDIX B. OLD FARM. & 8. d. By satis Land . . . 2 ~ 5 E A : . . . 5 56,337 0 0 Works, Tanks, &c. ; f : ; 2 4 3 ‘ 5 . 91,479 0 0 Stock and Plant . 2 : é ° . . é 4 i 22,728 0 0 —— 170,544 0 0: NEW FARM. Lanps.—Re Wiley’s Lease . i . e: . . - y ‘ 5 1,500 0 0 » Perkins’ . . = . . . . 164 0 0 5, Housman (Freehold) . . . 6,249 0 0 », Harlof Bradford (Freehold) . . * : 38,484 0 0 » Bagot (Freehold) . ‘ 3 a . . 5 49,498 0 0 » Newton (Freehoid) . ' é . 11,173 0 0 » Goldingay (Freehold) . e F . . 5 3,732 0 0 110,800 0 0» WorkKS.—Main Conduit . : : 2 . . . . 33.256 0 0 3 ft. 6 in. Conduit. * : 3 = . 3,544 0 0 Laying out and Draining . . A . 5 46,979 0 0 , New Buildings . ° : . 20,119 0 0 Repairs to Old Buildings . . 599 0 0 Permanent Carriers e e 8,802 0 0 113,299 0 0: Live Stock and Farm Implements . « 4 5 4 5 . . e * 9,052 0 0- 403,695 0 0: ON THE BIRMINGHAM, TAME, AND REA DISTRICT DRAINAGE. 507 APPENDIX C. INCOME AND EXPENDITURE FROM JANUARY 1st 10 DECEMBER 31st, 1885. INCOME. OUTLET FARM, Sale of Manure . ‘ . Fy 3 7 0 OJ] Sale of Rye Grass and other Crops and 4,960 15 10 Pumping Sewage . . . . 104 0 0 Cattle Ley Sundries . e ‘ : é 3 0 4 9] Sale of Milk . » ‘ 4 : - 4,406 18 7 ———_| Sale of Stock . & 3 . S . 10,641 0 3 £111 4 9 -—— £20,008 14 8 EXPEN DITURE. OUTLET. FARM. Wages, including Lime for Disinfecting 9,025 12 0 | Wages. - : 5,047 1 5 Horse Keep, Veterinary Attendance,Re- 35611 6 Seeds, Plants, &e. : 508 18 11 pairing Harness, Carts, &e. Horse Hire, Keep, and Cattle Keep . 4,768 14 5 Timber, Ironwork, Bricks, Tools, Coal, 1,064 14 7 | Stock Purchased * . 7,760 7 6 Coke, and Repairs to Machinery Miscellaneous, including Tools . 930 8 2 Horse Hire, Boat Hire, and Tonnage 174 9 5! Rent, Rates,and Taxes . 2 . 380618 5 Rent, Rates, Taxes, and Gas . ; x «dren 9 —_ — Miscellaneous 2 5 a : ‘ 94 2 9 £22,822 8 10 £11,502 11 0 TRANSACTIONS OF THE SECTIONS. TRANSACTIONS OF THE SECTIONS. Section A.—MATHEMATICAL AND PHYSICAL SCIENCE. ‘PRESIDENT OF THE SECTION—Professor G. H. DARWIN, M.A., LL.D., F.R.S., F.R.A.S. THURSDAY, SEPTEMBER 2. The PREsIDENT delivered the following Address :— _A MERE catalogue of facts, however well arranged, has never led to any important ‘scientific generalisation. For in any subject the facts are so numerous and many- sided that they only lead us to a conclusion when they are marshalled by the light of some leading idea. A theory is then a necessity for the advance of science, and ‘we may regard it asthe branch of a living tree, of which facts are the nourishment. In the struggle between competing branches to reach the light some perish, and others form vigorous limbs. And as in a tree the shape of the young shoot can -give us but little idea of the ultimate form of the branch, so theories become largely transformed in the course of their existence, and afford in their turn the parent -stem for others. The success of a theory may be measured by the extent to which it is capable of assimilating facts, and by the smallness of the change which it must undergo in the process. Every theory which is based on a true perception of facts is to some -extent fertile in affording a nucleus for the aggregation of new observations. And a theory, apparently abandoned, has often ultimately appeared to contain an element -of truth, which receives acknowledgment by the light of later views. It will, I think, be useful to avail myself of the present occasion to direct your attention to a certain group of theories, which are still in an undeveloped and -somewhat discordant condition, but which must form the nucleus round which many observations have yet to be collected before these theories and their descend- ants can make a definitely accepted body of truth. If I am disposed to criticise some of them in their actual form, I shall not be understood as denying the great ‘service which has been rendered to science by their formulation. Great as have been the advances of geology during the present century, we have no precise knowledge of one of its fundamental units. The scale of time on which we must suppose geological history to be drawn is important not only for geology itself, but it has an intimate relation with some of the profoundest questions of biology, physics, and cosmogony. We can hardly hope to obtain an accurate measure of time from pure geology, for the extent to which the events chronicled in strata were contemporaneous is not written in the strata themselves, and there are long intervals of time of which no record has been preserved. An important step has been taken by Alfred Tylor, Croll, and others, towards the determination of the rate of action of geological agents.1 From estimates of 1 Geikie, Textbook of Geology, 1882, p. 442. 512 REPORT—1886. the amount of sediment carried down by rivers, it appears that it takes from 1,000 to 6,000 years to remove one foot of rock from the general surface of a river basin. 2 From a consideration of the denuding power of rivers, and a measurement of the thickness of stratified rock, Phillips has made an estimate of the period of time comprised in geological history, and finds that, from stratigraphical evidence alone, we may regard the antiquity of life on the earth as being possibly between 38 and 96 millions of years.’ Now while we should perhaps be wrong to pay much attention to these figures, yet at least we gain some insight into the order of magnitude of the periods with which we have to deal, and we may feel confident that a million years is not an infinitesimal fraction of the whole of geological time. It ishardly to be hoped, however, that we shall ever attain to any very accurate Imowledge of the geological time scale from this kind of argument. But there is another theory which is precise in its estimate, and which, if acceptable from other points of view, will furnish exactly what is requisite. Mr. Croll claims to prove that great changes of climate must be brought about by astronomical events of which the dates are known or ascertainable.? The pertur- bation of the planets causes a secular variability in the eccentricity of the earth’s. orbit, and we are able confidently to compute the eccentricity for many thousands of years forward and backward from to-day, although it appears that, in the opinion of Newcomb and Adams, no great reliance can be placed on the values deduced from the formule at dates so remote as those of which Mr, Croll speaks. According to Mr. Croll, when the eccentricity of the earth’s orbit is at its maximum, that hemisphere which has its winter in aphelion would undergo a glacial period. Now, as the date of great eccentricity is ascertainable, this would explain the great ice-age and give us its date. The theory has met with a cordial acceptance on many sides, probably to a great extent from the charm of the complete answer it affords to one of the great riddles of geology. Adequate criticism of Mr. Croll’s views is a matter of great difficulty on account of the diversity of causes which are said to co-operate in the glaciation. In the case of an effect arising from a number of causes, each of which contributes its share, it is obvious that if the amount of each cause and of each effect is largely conjectural the uncertainty of the total result is by no means to be measured by the uncertainty of each item, but is enormously augmented. Without going far into details it may be said that these various concurrent causes result in one fundamental proposition with regard to climate, which must be regarded as the key- stone of the whole argument. That proposition amounts to this—that climate is unstable. : Mr. Croll holds that the various causes of change of climate operate enter se in such a way as to augment their several efficiencies. Thus the trade-winds are driven by the difference of temperature between the frigid and torrid zones, and if from the astronomical cause the N. hemisphere becomes cooler the trade-winds on that hemisphere encroach on those of the other, and the part of the warm oceanic current, which formerly flowed into the cold north zone, will be diverted into the S. hemisphere. Thus the cold of the N. hemisphere is augmented, and this in its turn displaces the trade-winds further, and this again acts on the ocean-currents, and so on; and this is neither more nor less than instability. But if climate be unstable, and if from some of those temporary causes, for which no reasons can as yet be assigned, there occurs a short period of cold, then surely some even infinitesimal portion of the second link in the chain of causation must exist; and this should proceed as in the first case to augment the departure from the original condition, and the climate must change. In a matter so complex as the weather, it is at least possible that there should be instability when the cause of disturbance is astronomical, whilst there is stability 1 Phillips, Life on the Harth. Rede Lecture, 1860, p. 119. 2 Climate and Time. TRANSACTIONS OF SECTION A. 513 in an ordinary sense. If this is so, it might be explained by the necessity for a prolonged alteration in the direction of prevailing winds in order to affect oceanic currents.? However this may be, so remarkable a doctrine as the instability of climate must certainly be regarded with great suspicion, and we should require abundant proof before accepting it. Now there is one result of Mr. Croll’s theory which should afford almost a crucial test of its acceptability. In consequence of the pre- cession of the equinoxes the conditions producing glaciation in one hemisphere must be transferred to the other every 10,000 years, If there is good geological evidence that this has actually been the case, we should allow very great weight to the astronomical theory, notwithstanding the difficulties in its way. Mr. Croll has urged that there is such evidence, and this view has been recently strongly supported by M. Blytt.? Other geologists do not, however, seem convinced of the conclusive- ness of the evidence. Thus Mr. Wallace,’ whilst admitting that there was some amelioration of climate from time to time during the last glacial period, cannot agree in the regular alternations of cold and warm demanded by Mr. Croll’s theory. To meet this difficulty he proposes a modification. According to his view large eccentricity in the earth’s orbit will only produce glaciation when accompanied by favourable geographical conditions. And when extreme glaciation has once been established in the hemisphere which has its winter in aphelion, the glaciation will persist, with some diminution of intensity, when precession has brought round the perihelion to the winter. In this case, according to Wallace, glaciation will be simultaneous on both hemispheres. Again he contends that, if the geographical conditions are not favourable, astronomical causes alone are not competent to produce glaciation. There is agreement between the two theories in admitting instability of climate at first, when glaciation is about to begin under the influence of great eccentricity of the orbit, but afterwards Wallace demands great stability of climate. Thus he maintains that there is great stability in extreme climates, either warm or cold, whilst there is instability in moderate climates. I cannot perceive that we have much reason from physical considerations for accepting these remarkable proposi- tions, and the acceptance or rejection of them demands an accurate knowledge of the most nicely balanced actions, of which we have as yet barely an outline. Ocean currents play a most important part in these theories, but at this moment our knowledge of the principal oceanic circulation, and of its annual variability, is very meagre. In the course of a few years we may expect a considerable accession to our knowledge, when the Meteorological Office shall have completed a work but just begun—viz., the analysis of ships’ logs for some sixty years, for the purpose of laying down in charts the oceanic currents. With regard to the great atmospheric currents even the general scheme is not yet known. Nearly thirty years ago Professor James Thomson gave before this Association at Dublin an important suggestion on this point. As it has been passed over in complete silence ever since, the present seems to be a good oppor- tunity of redirecting attention to it. According to Halley’s theory of atmospheric circulation, the hot air rises at the equator and floats north and south in two grand upper currents, and it then acquires a westward motion relatively to the earth’s surface, in consequence of the earth’s rotation. Also the cold air at the pole sinks and spreads out over the earth’s surface in a southerly current, at first with a westerly tendency, because the air comes from the higher regions of the atmosphere, and afterwards due south, and then easterly, when it is left behind by the earth in its rotation. Now Professor Thomson remarks that this theory disagrees with fact in as far as that in our latitudes, the winds, though westerly, have a poleward tendency, instead of the reverse. In the face of this discrepancy he maintains that ‘the great circulation already described does actually occur, but occurs subject to this modification, that a thin 1 Zoppritz, Phil. Mag. 1878. 2 Nature, July 8 and 15, 1886. : : 3 Island Life. 1886. LL 514 REPORT—1886. atratum of air on the surface of the earth in the latitudes higher than 30°—a stratum in which the inhabitants of those latitudes have their existence, and of which the movements constitute the observed winds of those latitudes—heing, by friction and impulses on the surface of the earth, retarded with reference to the rapid whirl or vortex motion from west to east of the great mass of air above it, tends to flow towards the pole, and actually does so flow to supply the partial void in the central parts of that vortex, due to the centrifugal force of its revolution. Thus it appears that in the temperate latitudes there are three currents at different heights—that the uppermost moves towards the pole, and is part of a grand primary circulation between the equatorial and polar regions; that the lower- most moves also towards the pole, but is only a thin stratum forming part of a secondary circulation; that the middle current moves from the pole, and constitutes the return current for both the preceding ; and that all these three currents have a prevailing motion from west to east.’? Such, then, appears to be our present state of ignorance of these great terrestrial actions, and any speculations as to the precise effect of changes in the annual dis- tribution of the sun’s heat must be very hazardous until we know more precisely the nature of the thing changed. When looking at the astronomical theory of geological climate as a whole, one cannot but admire the symmetry and beauty of the scheme, and nourish a hope that it may be true; but the mental satisfaction derived from our survey must not blind us to the doubts and difficulties with which it is surrounded. And now let us turn to some other theories bearing on this important point of geological time. Amongst the many transcendent services rendered to science by Sir William Thomson, it is not the least that he has turned the searching light of the theory of energy on to the science of geology. Geologists have thus been taught that the truth must lie between the cataclysms of the old geologists and the uniformi- tarianism of forty years ago. It is now generally believed that we must look for a greater intensity of geologic action in the remote past, and that the duration of the geologic ages, however little we may be able mentally to grasp their greatness, must bear about the same relation to the numbers which were written down in the older treatises on geology, as the life of an ordinary man does to the age of Methuselah. The arguments which Sir William Thomson has adduced in limitation of geo- logical time are of three kinds. I shall refer first to that which has been called the argument from tidal friction; but before stating the argument itself it will be convenient to speak of the data on which the numerical results are based. Since water is not frictionless, tidal oscillations must be subject to friction, and this is evidenced by the delay of twenty-four to thirty-six hours, which is found to occur between full and change of moon and spring-tide. An inevitable result of this friction is that the diurnal rotation of the earth must be slowly retarded, and that we who accept the earth as our timekeeper must accuse the moon of a secular acceleration of her motion round the earth, which cannot be otherwise explained. It is generally admitted by astronomers that there actually is such an unexplained secular acceleration of the moon’s mean motion. No passage in Thomson and Tait’s ‘Natural Philosophy’ has excited more general interest than that in which Adams is quoted as showing that, with a certain value for the secular acceleration, the earth must in a century fall behind a perfect chronometer, set and rated at the beginning of the century, by twenty-two seconds. Unfortunately this passage in the first edition gave an erroneous com- plexion to Adams's opinion, and being quoted, without a statement of the premisses, has been used in popular astronomy as an authority for establishing the statement that the earth is actually a false timekeeper to the precise amount specified. In the second edition (in the editing of which I took part) this passage has been rewritten, and it is shown that Newcomb’s estimate of the secular acceleration only gives about one-third of the retardation of the earth’s rotation, which resulted trom Adams’s value. The last sentence of the paragraph here runs as follows :— 1 Brit. Assoc. Report, Dublin, 1857, p, 38-9, TRANSACTIONS OF SECTION A. 515 «It is proper to add that Adams lays but little stress on the actual numerical values which have been used in this computation, and is of opinion that the amount of tidal retardation of the earth’s rotation is quite uncertain.’ Thus, in the opinion of our great physical astronomer, a datum is still wanting for the determination of a limit to geological time, according to Thomson’s argument. However, subject to this uncertainty, with the values used by Adams in his computation, and with the assumption that the rate of tidal friction has remained constant, then a thousand million years ago the earth was rotating twice as fast as at present. In the last edition of the ‘Natural Philosophy’ the argument from these data runs thus :— ‘Tf the consolidation of the earth took place then or earlier, the ellipticity of the upper layers (of the earth’s mass) must have been 54, instead of about 4,, as it is at present. It must necessarily remain uncertain whether the earth would from time to time adjust itself completely to a figure of equilibrium adapted to the rotation. But it is clear that a want of complete adjustment would leave traces in a preponderance of land in equatorial regions. The existence of large continents and the great effective rigidity of the earth’s mass render it improbable that the adjustment, if any, to the appropriate figure of equilibrium would be complete. The fact, then, that the continents are arranged along meridians, rather than in an equatorial belt, affords some degree of proof that the consolidation of the earth took place at a time when the diurnal rotation differed but little from its present value. It is probable, therefore, that the date of consolidation is considerably more recent than a thousand million years ago.’ I trust it may not be presumptuous in me to criticise the views of my great master, at whose intuitive perception of truth in physical questions I have often marvelled, but this passage does not even yet seem to me to allow a sufficiently jarge margin of uncertainty. It will be observed that the argument reposes on our certainty that the earth possesses rigidity of such a kind as to prevent its accommodation to the figure and arrangement of density appropriate to its rotation. In an interesting dis- cussion on subaérial denudation, Croll has concluded that nearly one mile may have been worn off the equator during the past 12,000,000 years, if the rate of denudation all along the equator be equal to that of the basin of the Ganges.! Now, since the equatorial protuberance of the earth when the ellipticity is ;1, is fourteen miles greater than when it is ;1;, it follows that 170,000,000 years would suffice to wear down the surface to the equilibrium figure. Now let these numbers be halved or largely reduced, and the conclusion remains that denudation would suffice to obliterate external evidence of some early excess of ellipticity. If such external evidence be gone,? we must rely on the incompatibility of the inown value of the precessional constant with an ellipticity of internal strata of equal density greater than that appropriate to the actual ellipticity of the surface. Might there not be a considerable excess of internal ellipticity without our being cognisant of the fact astronomically ? And, further, have we any right to feel so confident of the internal structure of the earth as to be able to allege that the earth would not through its whole mass adjust itself almost completely to the equilibrium figure ? Tresca has shown in his admirable memoirs on the flow of solids that when the stresses rise above a certain value the solid becomes plastic, and is brought into what he calls the state of fluidity. I do not know, however, that he determined at what stage the flow ceases when the stresses are gradually diminished. It seems probable, at least, that flow will continue with smaller stresses than were initially ? Croll, Climate and Time, 1885, p. 336. * I find by a rough calculation that >ths of the land in the N. hemisphere is in the equatorial half of that hemisphere, viz. between 0° and 30° N. lat.; and that 28ths of the land in the S. hemisphere is in the equatorial half of that hemisphere, viz. between 0° and 30° S. lat. Thus for the whole earth, 1% ths of all the land lies in the equatorial half of its surface, between 30° N.and §. lat. In this computation the Mediterranean, Caspian, and Black Seas are treated as land. Lu? 516 REPORT—1886. necessary to start it. But if this is so, then, when the earth has come to depart both internally and externally from the equilibrium condition a flow of solid will set in, and will continue until a near approach to the equilibrium condition is attained. When we consider the abundant geological evidence of the plasticity of rock, and of the repeated elevation and subsidence of large areas on the earth’s surface, this view appears to me more probable than Sir William Thomson’s. On the whole, then, I can neither feel the cogency of the argument from tidal friction itself, nor, accepting it, can I place any reliance on the limits which it assigns to geological history. The second argument concerning geological time is derived from the secular cooling of the earth, We know in round numbers the rate of increase of temperature, or temperature gradient, in borings and mines, and the conductivity of rock. These data enable us to compute how long ago the surface must have had the temperature of melting rock, and when it must have been too hot for vegetable and animal life. Sir William Thomson, in his celebrated essay on this subject,! concludes from this argument that ‘ for the last 96,000,000 years the rate of increase of tempera- ture underground has gradually diminished from about jth to about ith of a degree Fahrenheit per foot. . . . Is not this, on the whole, in harmony with geo- logical evidence, rightly interpreted ? Do not the vast masses of basalt, the general appearances of mountain ranges, the violent distortions and fractures of strata, the great prevalence of metamorphic action (which must have taken place at depths of not many miles, if so much), all agree in demonstrating that the rate of increase of temperature downwards must have been much more rapid, and in rendering it probable that volcanic energy, earthquake shocks, and every kind of so-called plutonic action, have been, on the whole, more abundantly and violently operative in geological antiquity than in the present age ? ’ Now, while I entirely agree with the general conclusion of Sir William Thom- _ son, it is not unimportant to indicate a possible flaw in the argument. This flaw will only be acknowledged as possible by those who agree with the previous criti- cism on the argument from tidal friction. The present argument as to the date of the consolidation of the earth reposes on the hypothesis that the earth is simply a cooling globe, and there are reasons why this may not be the case. The solidification of the earth probably began from the middle and spread to the surface. Now is it not possible, if not probable, that after a firm crust had been formed, the upper portion still retained some degree of viscosity ? If the interior be viscous, some tidal oscillations must take place in it, and, these being subject to friction, heat must be generated in the viscous portion ; moreover the diurnal rotation of the earth must be retarded. Some years ago, ina paper on the tides of a spheroid, viscous throughout the whole mass,” I estimated the amount and distribution of the heat generated, whilst the planet’s rotation is being retarded and the satellite’s distance is being increased. It then appeared that on that hypothesis the distribution of the heat must be such that it would only be possible to attribute a very small part of the observed temperature gradient to such a cause. Now, with a more probable internal constitution for the earth in early times, the result might be very different. Suppose, in fact, that it is only those strata which are within some hundreds of miles of the surface which are viscous, whilst the central portion is rigid. Then, when tidal friction does its work the same amount of heat is generated as on the hypothesis of the viscosity of the whole planet, but instead of being distributed throughout the whole mass, and principally towards the middle, it is now to be found in the more superficial layers. In my paper it is shown that with Thomson’s data for the conductivity of rock and the temperature gradient, the annual loss of heat by the earth is one 260 millionth part of the earth’s kinetic energy of rotation. Also, if by tidal friction the day is reduced from D, hours to D hours, and the ? Republished in Thomson and Tait’s Watural Philosophy, Appendix D. * Phil. Trans. Part II. 1879 TRANSACTIONS OF SECTION A. 517 moon’s distance augmented from I, to II earth’s radii, the energy which has been converted into heat in the process is gD \* Lge a) ) : Sete . —1— 884 (=-— ; ti ey of rot : (;,) 1-— 88 (~ tT, times the earth’s kinetic energy of rotation From these data it results that the heat generated in the lengthening of the day from twenty-three to twenty-four hours is equal to the amount of heat lost by the earth, at its present rate of loss, in 23,000,000 years. Now if this amount of heat, or any sensible fraction of it, was actually generated within a few hundred miles of the earth's surface, the temperature gradient in the earth must be largely due to it, instead of to the primitive heat of the mass. Such an hypothesis precludes the assumption that the earth is simply a cooling mass, and would greatly prolong the possible extension of geological time. It must be observed that this view is not acceptable unless we admit that the earth can adjust itself to the equilibrium figure adapted to its rotation. It seems also worthy of suggestion that our data for the average gradient of temperature may be somewhat fallacious. Recent observations? show that the lower stratum of the ocean is occupied by water at near the freezing temperature, whilst the mean annual temperature of the earth’s surface, where the borings have been made, must be at least 30° higher. It does not then seem impossible that the mean temperature gradient for the whole earth should differ sensibly from the mean gradient in the borings already made. The foregoing remarks have not been made with a view of showing Sir William Thomson's argument from the cooling of the earth to be erroneous, but rather to maintain the scientific justice of assigning’ limits of uncertainty at the very least as wide as those given by him. Professor Tait ® cuts the limit down to 10,000,000 years; he may be right, but the uncertainties of the case are far too great to justify us in accepting such a narrowing of the conclusion. The third line of argument by which a superior limit is sought for the age of the solar system appears by far the strongest. This argument depends on the amount of radiant energy which can have been given out by the sun. The amount of work done in the concentration of the sun from a condition of infinite dispersion may be computed with some accuracy, and we have at least a rough idea of the rate of the sun’s radiation. From these data Sir William ‘Thomson concludes :—* ‘It seems, therefore, on the whole most probable that the sun has not illu- minated the earth for 100,000,000 years, and almost certain that he has not done 80 for 500,000,000 years. As for the future, we may say, with equal certainty, that inhabitants of the earth cannot continue to enjoy the light and heat essential to their life for many million years longer unless sources now unknown to us are prepared in the great storehouse of creation.’ This result is based on the value assigned by Pouillet and Herschel to the sun’sradiation. Langley has recently made a fresh determination, which exceeds Pouillet’s in the proportion of eight to fives With Langley’s value Thomson’s estimate of time would have to be reduced by the factor five-eighths, In considering these three arguments I have adduced some reasons against ’ Since the meeting of the Association Sir William Thomson has expressed to me his absolute conviction that, with any reasonable hypothesis as to the degree of viscosity of the more superficial layers, and as to the activity of tidal friction, the disturbance of temperature gradient through internal generation of heat must be ‘quite infinitesimal. 7 «Challenger’ Expedition. * Recent Advances in Physical Science (1885). * Thomson and Tait, Nat. Phil. Appendix E. * Langley (Ann. Rep. R. A. S. 1885) estimates that 3 calories per minute are received by a square centimetre at distance unity. This gives for the total annual radiation of the sun 4°38 x 10% calories. Thomson gives as Pouillet’s estimate 6 x 10" times the heat required to raise 1 lb. of water 1° Cels., or 2°72 x 10®* calories. 518 REPORT—1 886. the validity of the first argument, and have endeavoured to show that there are | elements of uncertainty surrounding the second; nevertheless they undoubtedly constitute a contribution of the first importance to physical geology. Whilst, then, we may protest against the precision with which Professor Tait seeks to deduce results from them, we are fully justified in following Sir William Thomson, who says that ‘the existing state of things on the earth, life on the earth, all geological history showing continuity of life, must be limited within some such period of past time as 100,000,000 years,’ If I have carried you with me in this survey of theories bearing on geological time, you will agree that something has been acquired to our knowledge of the past, but that much more remains still to be determined. Although speculations as to the future course of science are usually of little avail, yet it seems as likely that meteorology and geology will pass the word of command to cosmical physics as the converse. At present our knowledge of a definite limit to geological time has so little precision that we should do wrong to summarily reject any theories which appear to demand longer periods of time than those which now appear allowable. In each branch of science hypothesis forms the nucleus for the aggregation of observation, and as long as facts are assimilated and co-ordinated we ought to follow our theory. Thus even if there be some inconsistencies with a neighbouring science we may be justified in still holding to a theory, in the hope that further knowledge may enable us to remove the difficulties. There is no criterion as to what degree of inconsistency should compel us to give up a theory, and it should be borne in mind that many views have been utterly condemned when later knowledge has only shown us that we were in them only seeing the truth from another side. The following Papers and Report were read :— 1. Communication from the Grenada Eclipse Expedition. By Doyatp MacAuistrr, M.A., M.D., B.Sc. 2. First Report on owr Experimental Knowledge of the Properties of Matter. By P. T. May, M.A.—See Reports, p. 100. 3. On the Critical Mean Curvature of Liquid Surfaces of Revolution. By Professor A. W. Ricker, M.A., F.R.S. Let a mass of liquid or a liquid film be attached to two equal circular rings, the planes of which are perpendicular to the line joining their centres. It will form a surface of revolution, the equation of which is, according to Beer, y’ =a’ cos* f + B* sin® g, wv =aEK+ BF, where F and E are elliptic integrals of the first and second kinds respectively, the amplitude being @, and the modulus « = V a? —8?/a=sin 6. If 6 be conceived as increasing from 0, when it is in the first quadrant the figure will be an unduloid lying between the cylinder and the sphere, in the second quadrant a nodoid, the limits of which are the sphere and a circle. In the third and fourth quadrants the figure wili be dice-box-shaped with a contraction in the middle, being a nodoid in the third and an unduloid in the fourth quadrant. The one passes into the other through the catenoid. If now we suppose the rings to be at a fixed distance apart and the volume of the surface to be altered, the curvature will change, and the direction of the change: will depend on the diameter and distance apart of the rings, and on the magnitude of the maximum or minimum vrdinate (the principal ordinate), which lies halfway TRANSACTIONS OF SECTION A. 519 between them. The object of the paper is to investigate the general relation be- tween these quantities when the mean curvature is a maximum or minimum, if the changes in the form of the film take place subject to the conditions that the diameter and distance of the rings are constant. It has been.recently shown by Professor Reinold and the author that, if these conditions hold, (PE —f°F +a7A, cot p,)da+a?(F—E+A, tan $,)58 =0, where ¢, is the upper limit of the integrals and A, = / 1 —sin? 6 sin? dy. Writing this in the form Ada + B38 =0, it is proved that the curvature has in general a critical value when A —B=0; so that 2E — F(1 + cos? 6) + 2A, cot 26, =0 is a condition which must be satisfied by @ and q,. To find values of ¢, corresponding to given values of 6 the equation must be solved by trial ; but it is proved that, if a pair of corresponding values is given when 6 lies (say) in the first quadrant, the values of , can be at once found which correspond to 7-6, +0, and 2n— 0. The values of ¢, corresponding to 6 and r—6 are equal, and, if ¢, be the value corresponding to 7 +6 and 27 —8@, it is given by the equation tan d, tan (r—¢,) = sec 0. By means of these equations a curve can be drawn, showing the relations between ¢, and 6,and thence are found the values of p/Y, X/p and X/Y, where 2Y, 2X, and 2p are the diameter and distance of the rings and the magnitude of the principal diameter. If we now conceive the two rings gradually to approach or recede from each other, and the principal diameter to be altered so that the condition of critical curvature is always fulfilled, it is proved that the changes in its form would be as follows :— Beginning with the cylinder the distance of the rings is (as has been shown by Maxwell, Art. Capillarity, ‘Enc. Brit.’) half their circumference. As the diameter increases the rings move apart, and the distance between them is a maximum when 6 = 64:2°, being 17 per cent, greater than in the case of the cylinder. When 6=90°, the figure is a sphere, and the distance between the rings is about 4 per cent. less than in the case of the cylinder. The sphere has a larger diameter than any other figure of critical curvature. The surface next becomes a nodoid, and the distance between the rings diminishes till when @=180° they touch, and thus the surface reduces to a circle. In the next quadrant the rings separate, but the figure is now dice-box-shaped, and the pressure exerted by the film is out- wards. When 6=270°, the figure is the catenoid. The principal ordinate is then less than that of any other figure of critical curvature, and the radius of the rings isa mean proportion between this minimum ordinate and the maximum which was attained in the case of the sphere. The same relation holds between the principal ordinates of any two figures which correspond to values of 6 which differ by 180°. In the fourth quadrant the figure becomes an unduloid, the pressure is inwards, the rings continue to separate, and the ratio of the distance between the rings to the principal ordinate is a maximum when 6 = 298°. In the paper tables and curves are given to illustrate the ‘march’ of these functions. To secure continuity the problem is discussed without reference to the question as to whether the surfaces are in stable equilibrium. Tn conclusion it is shown that by means of the curves we can solve a number of problems with sufficient accuracy for practical purposes. Thus, if any two of the three quantities, the diameter of the rings, the distance between them, and the diameter of the surface of critical curvature, are given, the third can be found. 4. A Mercurial Air-pump. By J. T. Borromury, M.A., F.R.S.E. The primary object of the pump described in this paper is the removal of the 520 REPORT— 1886. mercury which works the pump from contact with the external atmosphere. When the Sprengel pump is used for producing and maintaining a nearly complete vacuum during a course of experimenting which lasts over a good many days or weeks, it is found that the mercury running down through the pump and discharging into the open air takes up minute quantities of air, which it carries with it in a state of very intimate mixture. This intimately mixed air the mercury does not lose in passing through the air-traps, but the air is deposited along the walls of the pump head, and collects into bubbles which are at first exceedingly minute, and gradually in- crease to a sensible size. These bubbles ultimately escape from contact with the glass and deteriorate the vacuum. The pump described consists of a combination of a single fall Sprengel with a Geisler pump, and in addition the movable reservoir is furnished with an air-tight stopcock, by means of which the air is got rid of from that reservoir and prevented from re-entering. In using the pump it is first worked as an ordinary Geisler pump till nearly all the air of the enclosure to be exhausted has been removed. In this way advantage is taken of the comparatively great speed of the Geisler pump. When a good exhaustion has been obtained the stopeocks and the lift of the movable reservoir are so managed that the pump is thereafter used as a Sprengel—the small remain- ing traces of air being pumped by the Sprengel into the exhausted chamber of the Geisler ; and when a sufficient quantity of air has been collected in this chamber it can be removed by a single Geisler operation. 5. On the Cutting of Polarising Prisms. By Professor Sirvanus P. Txompson, D.Sc. The author described a method of cutting Nicol prisms analogous to that communicated in 1885, the end faces being inclined at 70° to a natural face of the crystal, and having a line of mutual intersection at right angles to the natural long edges, The author also described a new method devised by Mr. Ahrens of cutting the triple polarising prism described by the author at the Aberdeen meeting. The new method of cutting effects a great saving of spar, and depends upon finding a certain characteristic plane’in the crystal which defines the external longitudinal faces of the prisms, 6. On a Varying Cylindrical Lens. By Tempest Anprrson, M.D., B.Sc. A cylindrical lens of continuously varying power has long been a desideratum, and one was constructed and described by Professor Stokes, Pres. R.S., at page 10 of the Report of the British Association for 1849. He points out that— ‘If two plano-cylindrical lenses of equal radius, one concave and the other convex, be fixed one in the lid and the other in the body of a small round box with a hole in the top and bottom, so as to be as nearly as possible in contact, the lenses will neutralise one another when the axes of the surfaces are parallel, and by merely turning the lid round an astigmatic lens may be formed, of a power varying con- tinuously from zero to twice the astigmatic power of either lens.’ This very beautiful optical contrivance has the disadvantage that the refraction varies from zero in both directions at once, the refraction at any given position of the lenses being positive in one meridian, and negative or concave to an equal degree in a meridian at right angles to the first ; moreover, there is no fixed axis in which the refraction is either zero or any other constant amount. It has in consequence never come into extensive use in the determination of the degree of astigmatism. The author has planned a cylindrical lens in which the axis remains constant in direction and amount of refraction, while the refraction in the meridian at right angles to this varies continuously. A cone may be regarded as a succession of cylinders of different diameters graduating into one another by exceedingly small steps, so that if a short enough portion be considered, its curvature at any point may be regarded as cylindrical. A lens with one side plane and the other ground on a conical tool is therefore TRANSACTIONS OF SECTION A. 521 a concave cylindrical lens varying in concavity at different parts according to the diameter of the cone at the corresponding part. Two such lenses mounted with axes parallel and with curvatures varying in opposite directions produce a com- pound cylindrical lens whose refraction in the direction of the axes is zero, and whose refraction in the meridian at right angles to this is at any point the sum of the refractions of the two lenses. This sum is nearly constant for a considerable distance along the axis so long as the same position of the lenses is maintained. Tf the lenses be slid one over the other in the direction of their axes, this sum changes, and we have a varying cylindrical lens, The lens is graduated by marking on the frame the relative position of the lenses when cylindrical lenses of Inown power are neutralised. It was found by a practical optician to be impossible to work glasses on a cone of large diameter, consequently a conical tuol was constructed with an angle of 45° at the apex, and 8 inches diameter at the base. A glass about 4 inches long was ground on the sides of this near the base, and as the resulting lens if ground on plane glass would have been too concave for most purposes, the outer side of the glass was previously ground to a convex cylindrical curve, and its axis applied parallel to the generating line of the cone in the plane of the axis of the cone. The result was concavo-convex cylinders of varying power suitable for the practical measurement of astigmatism. Lenses were exhibited varying from 0 to —6DCy, and from 0 to +6DCy. 7. On the Law of the Propagation of Light. By Professor J. H. Poyntine, M.A., and H. F. J. Love, B.A. The authors describe a new method of proving that the intensity of illumina- tion of a screen varies inversely as the square of the distance from the source. The same experimental arrangement with slight modification allows us also to prove the law of absorption of light—a law which we believe has hitherto been assumed without verification by experiment. The arrangement is as follows :—Two illumi- nating surfaces at different distances are viewed through a narrow blackened tube, each surface occupying half the field of view. The illuminating powers of the two surfaces are adjusted till for a given distance of the tube they appear equally bright. They then appear equally bright for any other distance of the tube. This was verified both for air and for an absorbing medium consisting of a dilute alkaline solution of phenol-phthalein, which coloured the transmitted light violet. From this it can be shown that if I be the intensity of illumination of a screen eT ea 1) . When xv ¢=0 the medium is transparent. When ec differs from 0, e-¢ is the ‘coefficient of absorption.’ at distance 1 from the source, the illumination at a distance «x is 8. On a new form of Current-weigher for the Absolute Determination of the Strength of an Electric Current. By Professor James Biytu. The object of this paper is to describe a method of absolutely determining the strength of an electric current by measuring in grammes’ weight the electro-magnetic force between two parallel circular circuits, each carrying the same current. For convenience of calculation the circles have the same radius, and are placed with their planes horizontal. The construction of the instrument is as follows:—A delicate chemical balance is provided, and the scale-pans replaced by two suspended coils of wire. Each of these is made of a single turn of insulated copper wire (No. 16 about) fixed in a groove round the edge of an annular disc of glass or brass of suitable diameter. The disc is made as thin and light as possible consistent with perfect rigidity. By means of two vertical pillars of brass this annulus is attached to a rigid cross-bar of dry wood or vulcanite, in the middle of which is placed a hook for suspending 522 REPORT—1886. the whole from one end of the balance-beam. On each side of the hook, and equally distant from it, two slender rods of brass are screwed into the wooden bar,. which support two small platinum cups for holding mercury or dilute acid. The position of these cups is so adjusted that when the whole hangs freely the cups are in line with the terminal knife-edge of the balance-beam, and have their edges just slightly above its level. The free ends of the insulated wire surrounding the disc, after being firmly tied together for a considerable length and suitably bent, are soldered to the brass supports of the platinum cups, which thus serve as electrodes. by means of which a current may be sent through the suspended coil. A precisely similar coil is suspended from the other end of the balance-beam. We now come to the arrangement by means of which a current is led through the suspended coils, so as to interfere as little as possible with the sensibility of the balance. This constitutes the essential peculiarity of the instrument, and is effected in the following way :—An insulated copper wire, having its ends tipped with short lengths of platinum, is run along the lower edge of the beam, and is firmly lashed to it by well-rosined silk thread. The ends of this wire, bent twice at right angles, are so placed that their platinum tips dip vertically into one of each pair of the platinum cups which are attached to the vertical rods of the suspended coils. From the other cup of each pair proceed two similarly tipped copper wires, which run along the upper edge of the beam, and are also firmly tied to it. These wires, however, only proceed as far as the middle of the beam, where they are bent, first outwards, one on each side of the beam, at right angles to it, and then downwards, so that the platinum tips are vertical. The latter dip into two platinum cups attached to two vertical rods, which spring from the base-board of the balance. These rods are placed at equal distances on each side of the beam, and are of such length that the platinum cups are in line with the central kmife-edge of the beam, and have their edges just a little above its level. There are thus in all six cups and six dipping wires. Three of these are in line on one side of the beam, and three on the other. Also the line joining the points of each pair of dipping wires is made to coincide with the corresponding knife-edge ; and, further, the edges of the cups are all in the same plane when the balance is in equilibrium. From this it will be obvious that any motion of the beam in the act of weighing causes only a very slight motion of the platinum wires, which dip into the fluid contained ia the cups. The resistance, due to the viscosity of the fluid, is thus very small, even in the case of mercury, and much smaller when dilute acid is used. . In point of fact, the diminution of sensibility due to this cause is less than in the case of determining the specific gravity of solids by weighing in water in the ordinary way. With clean mercury it is quite easy to weigh accurately to a millizramme. The fixed coils, constituting two pairs, have the same diameter as the suspended coils, and, like them, are made of single turns of insulated wire wound round the edges of circular dises of glass or brass. The discs of each pair are fixed, at the requisite distance apart, to a cylindrical block of wood, so as to have their planes exactly parallel and their centres in the same straight line. To ensure this they are turned up and finished on the same cylindrical block on which they are finally to rest. When in position they are so placed that, when the balance is in equi- librium, each suspended coil hangs perfectly free to move with its plane horizontal and exactly midway between a pair of fixed coils. For this purpose, as will be seen, it is necessary that two large holes be drilled in the upper disc of each pair, so as to allow the brass pillars of the corresponding annular disc to pass freely through. When the connections are made, the current is led through the entire apparatus in such a way that, while the electro-magnetic force acting on the one suspended coil causes it to descend, the electro-magnetic force acting upon the other causes it to ascend. The total force tending to disturb the equilibrium of the balance is thus exactly four times that due to an equal current circulating in two parallel circles of the same diameter and with their planes at the same distance apart. The current- strength is estimated from the number of grammes required to restore the balance to equilibrium, the weights being placed in small scale-pans attached to the movable part of the apparatus. TRANSACTIONS OF SECTION A. 523. The electro-magnetic force between each fixed and the corresponding suspended coil is calculated from the formule given by Clerk Maxwell (vol. ii. p. 308), viz. :— a =e cosy | OF, — (1+ sec? y)E, where M =the potential energy between two parallel circles, each carrying unit current, 6=distance between their planes, a=radius of each coil, Bin yee Y Jda F, and E, = first and second complete elliptic integrals to modulus sin y. In one of the instruments constructed a=10°8 inches, 6= ‘566 inch, which give y = 87°, Fy =4:338653976, Ey = 1:005258587 ;s from which, if G denote the constant of the instrument and g=981, we have dM 1 G=4. re 4818. This gives for 1 ampére a force =-04818 gramme weight. Besides the one exhibited I have constructed several modifications of the in-- strument, only one of which, however, need be particularly mentioned. In it both the fixed and movable coils are replaced by flat spirals of wire, each of eleven turns. Here the practical construction is more difficult, and the calculation of the constant somewhat more laborious, unless one is content with merely integrating over the area of both the fixed and suspended spirals. This is, I think, however, hardly legitimate, at least with thickish wires, as we thereby suppose that electricity is circulating in the insulating spaces between the wiresas well as in the wires them- selves. To avoid this I have actually calculated the force exerted by each one of the coils of the fixed spiral upon each coil of the suspended spiral. This entails great labour, as the elliptic integrals have to be calculated for values of the modulus differing very slightly from each other. The labour, however, is worth the taking, as the attractive or repulsive force between two flat spirals is so much greater than that between two simple circles. 9. On the Proof by Cavendish’s Method that Electrical Action varies inversely’ as the Square of the Distance. By Professor J. H. Pornrine, M.A. The proof of the law of electrical action depending on the fact that. there is no electrification within a charged conductor was first given by Cavendish. His proof was made more general by Laplace, who has been followed by other writers, including Maxwell. Maxwell and MacAlister have also verified the experimental fact, repeating an investigation of Cavendish only recently published in Maxwell’s edition of the Cavendish papers. The proof may be analysed in the following way:—Take the case of a uniformly charged. sphere. The action at a point within it may be considered as the resultant of the actions of the pairs of sections of the surface by all the elementary cones, with the point as vertex. If, then, the resultant action is zero for all points and for all sizes of the sphere, it follows that the action of the pair of sections by each elementary cone is zero; and, since the sections of the surfaces are directly as the squares of the distances, the two sections neutralising each other, the force per unit area must be inversely as the squares of the distances. There appear to be two- objections to this proof. (1) That it takes no account of the always existing oppo- site charges. When the sphere, for instance, is positively charged, an equal and opposite negative charge is on the walls of the room, and the action of this should be considered. Probably this objection could be removed. (2) There isa solution 524 REPORT—1886. still simpler than the inverse square law—viz., that no element of the surface has any action within the closed conductor. If we suppose that a conductor is a com- plete screen to electrical action, then, whatever the law of the force exerted across an insulator, there will be no action within the conductor. In any null proof it is not sufficient merely to show that there is no action in the null arrangement, but it is also necessary to show that on disturbing the null arrangement some action is manifested. Now, in the case here considered it is impossible to obtain any action within the conductor in any statical arrangement ; it is only during changes of the system while charging or discharging that we can get a disturbance of the null arrangement. But here new phenomena come in, for we have currents, and there- fore electro-magnetic action. But, even disregarding the different kind of action occurring, the only experiment which I know of on this point was that of Faraday with his electrified cube. While the most violent charges and discharges were taking place on the outside of the cube, so that the null arrangement was probably disturbed, he found no action on his electroscope within. Possibly the actions were alternating, and so rapid that no electroscope of ordinary construction would reveal them. But he himself went into the cube, and he would probably be sensitive to rapidly alternating electromotive forces. It appears to me, then, that we cannot accept this proof, and must fall back upon the more direct proof of Coulomb. Ido not know whether Maxwell was aware of this objection; but it is worthy of note that in the remarkable fragment published since his death, as ‘An Elementary Treatise on Electricity,’ he returned to Coulomh’s proof, and was apparently building up the mathematical theory of electricity in a way quite different from that followed in his larger work. 10. On the Electrolysis of Silver and Copper, and its Application to the Standardising of Electric Current- and Potential-Meters. By Tomas Gray, B.Sc., F.L.S.E.} This paper contained an account of a large number of experiments on the electro- lysis of silver and copper, and its application to the standardising of electrical cur- rent- and potential-meters which have been made during the past year in the Physical Laboratory of Glasgow University. It forms a summary of the reports made from time to time to Sir William Thomson on this subject. In the earlier experiments pure silver sheet and solutions of pure silver nitrate were used for the electrolytic cells. The results obtained with these cells confirmed those obtained by Kohlrausch, Lord Rayleigh, and other observers as to the great accuracy obtainable with silver, and also as to the nature of the deposit and the care required in the manipulation of the experiment. The cathode plate consisted in almost all cases of a sheet of pure silver, placed, with its plane vertical, between two parallel sheets of the same metal. In a few experiments a platinum bowl was used very much in the same manner as that described by Lord Rayleigh in his paper to the Royal Society, but generally the plates of sheet silver were preferred. The mode of treating the plates both before and after the deposit was upon them is fully described, and it is pointed out that when the plate is made thoroughly clean, and its size properly proportioned to the strength of the current to be measured, the deposit is finely crystalline, and adheres very firmly to the plate. The best results were obtained when the current density at the cathode is between 3+; and ;3, of an ampére per square centimetre of the surface on which the deposit is taking place, the solution being supposed to contain five per cent. of silver nitrate. It is also pointed out that the loss of silver from the anode can be used satisfactorily as a check on the amount of silver deposited on the cathode, but that the current density at the anode must be considerably smaller than that which will give good deposits on the cathode. About 4, of an ampére per square centimetre is stated as the maximum current density at the anode which can be safely used if the loss of silver is to be weighed. A somewhat greater current density may be used at the cathode if the strength of the solution be increased, but the deposit is more roughly 1 Published in full in the Phil. Mag. for Nov. 1886. TRANSACTIONS OF SECTION A. 525: crystalline and less adherent. The current density cannot be increased in nearly the same proportion as the increase in the amount of silver nitrate in the solution, and hence when sheet silver cathodes are used the most economical and most satis— factory method is to use weak solutions and large plates. Rolled silver gives unsatisfactory results until the outside skin has been removed by use, polishing, or’ scraping. The later experiments described in the paper refer for the most part to copper, and include experiments on the uncertainty likely to arise from oxidation of the plate in drying, and while in the solution; the effect of the loss of weight due to direct chemical corrosion of the plate ; the effect of density of solution; of size of plate, or current density ; and of the addition of acid to the solution. It was found that there is no difficulty in washing and drying a plate without oxidising it sensibly, and methods are described for doing this. The loss of weight by corrosion in the liquid introduces an error which is nearly proportional to the surface of the plate exposed, and judging from Dr. Gore’s experiments it is also no doubt influ- enced by the temperature, if that be not constant ; but the effect of temperature was: not investigated. The amount of corrosion is also influenced to some extent by the density of the solution, and it appears to be least when the density is between 1:15: and 1:10. It is concluded that in the use of copper for standardising purposes the: current density and the density of the solution must be known, and the proper correction made on the electro-chemical equivalent to suit the particular circum- stances. If this be attended to, copper is capable of giving results within a tenth per cent. of accuracy, and is much more easily managed than silver. Silver is: preferable for the highest accuracy, but the accuracy which copper is capable of - giving is easily obtained, and it seems sufficient for most practical purposes. Experiments on the ratio of the electro-chemical equivalent of copper to that of silver were also made, and led to the conclusion that when the proper cor- rection for corrosion m the liquid is made the ratio is very nearly 0:2942, which, on the assumption of ‘001118 as the mass in grammes of the silver deposited by one coulomb of electricity, gives for the corresponding number for copper’ 0003290. When a nearly saturated solution of copper sulphate is used, and a current density of 4 of an ampére per square centimetre of the cathode, the amount of copper deposited by a coulomb of electricity is 0003287 gramme. It is pointed out that if the solution does not contain free acid there is a danger of obtaining too great an increase of weight, due apparently to the oxidation of the copper as it is being deposited. The same remark as that made above with regard to the silver anodes applies to the copper anodes if they are to be weighed. If the copper anodes are so small as to give a current density exceeding about the fortieth of an ampére per square centimetre the current is liable to stop almost completely, even when an electromotive force of as much as 25 volts is used to produce it: this is apparently due to excessive resistance at the surface of the anode. After a few minutes the current will again resume nearly its old strength, and gases will be given off freely at the anodes. These gases are readily dissolved by the liquid, and generally as the final result the gain and loss of copper do not differ very peeetly- although they always do differ—from those obtained when no gases are iven off. : Lastly, the arrangements of one of the standardising tables in Sir William Thomson’s laboratory are illustrated, and the different pieces of apparatus and the mode of using them described. 11. Description of a new Calorimeter for lecture purposes. By T. J. Baxer. The instrument consists of two exactly similar metallic air-thermometers mounted side by side with their U-shaped thermometer-tubes adjacent, so that their indications can be easily compared with each other. The air-vessel of each thermometer contains a cylindrical well, in which the substance to be experimented with is immersed. Each well is provided with a discharging tube furnished with a stopcock. The scale common to both ther- 526 REPORT—1886. mometers is of milk-glass, divided into 100 equal parts, both above and below zero, and let into the stand so as to constitute a translucent window which can be illu- minated from behind. By means of this instrument many thermal problems can be demonstrated before a large audience. FRIDAY, SEPTEMBER 3. The following Papers and Report were read :— 1. On the Physical and Physiological Theories of Colour-vision. By Lord Rayuzten, D.C.L., LL.D., Sec.R.8. 2. The Modern Development of Thomas Young’s Theory of Colour-vision. By Dr. Arruur Konta.—See Reports, p. 431. 3. On the Physical and Physiological Theories of Colowr-vision. By Professor Micuart Foster, M.D., Sec.R.8. A, On Hering’s and Young’s Theories of Colour-vision. By Joun TENNANT. The author briefly pointed out that, for the purposes of experiments in colour- mixture, Hering’s theory, like Young’s, has only three independent variables, and leads to the same general results. The author then considered the subject of simultaneous contrast, and showed that the only possibility of a deception of the judgment lies in the fallibility of the memory. Hence if two patches of the same grey (say) be seen simultaneously they ought, according to the psychological explanation, to appear the same what- ever their surroundings. This he showed, by an experiment with discs, is not the ease. Hence simultaneous contrast is a real and not an illusory effect, and demands a physiological explanation. The author, however, pointed out that there may be illusions of judgment in these cases owing to our habit of attributing permanence to local colour, and that this may account for some of the experiments which have been adduced in favour of the psychological explanation. The author then considered some of the difficulties of Hering’s theory, noticing— 1. That pure red and green are not complementary, as they should be. 2. A difficulty raised by Rood as to the relative intensity of a compound grey and its components. Lastly, the author considered the subject of changes of hue under varying intensity of light. He showed that if we assume that the functional processes of assimilation and dissimilation supposed by Hering draw their materials from, and contribute them to, a common source in the blood, it is natural to suppose that they are not wholly independent. He supposed yellow and green to correspond to the dissimilating blue, and red to the assimilating processes in their respective substances. He further supposed the red-green substance to be the most sensitive to drafts upon the common stock. These suppositions are found not only to explain the variations of hue with varying intensity of light, but also that tendency of colours when mixed with white light towards reddish violet, which has received no explanation from current theories. The author, without accepting Hering’s theory as established truth, thought it the best working hypothesis in the immediate future. TRANSACTIONS OF SECTION A. 527 5, Second Report of the Commuittee on Standards of Light.—See Reports, p.39. 6. Thermopile and Galvanometer combined. By Professor Grorce Forsss. 7, On the Intensity of Reflection from Glass and other Surfaces. By Lord Rayueien, D.C.L., LL.D., Sec. B.S. 8. A Note on some Observations of the Loss which Light suffers in passing through Glass. By Sir Jonn Conroy, Bart., M.A. The object of the experiments was to determine the percentage of light which passed through plates of glass of the same kind but of different thickness. The amount reflected from the first surface would be the same in all cases, and, assuming, as is usually done, that the same percentage of the incident light is reflected from both surfaces, the amount reflected from the second surface would be nearly the same—the difference in the amount of light which reached the second surface, owing to the increased absorption in the thicker plates, being but slight. It was therefore thought that this method would afford a means of determining not only the amount reflected, but also the amount absorbed, without assuming the truth of the formule for reflection. A photometer, similar to that described in Pickering’s ‘ Physical Manipulation ’ (pt. i. p. 182), was used for most of the observations ; but measurements were also made with a polarising photometer, and also with another arrangement, in which of +wo white surfaces illuminated by the same lamp, one was seen directly, and the other through the glass, If atmospheric absorption be neglected, which at such distances is of course insensible, the apparent brightness of an illuminated surface does not vary with the distance; no correction was therefore needed with this instrument for the optical shortening of the path of the ray, owing to the refrac- tive power of the glass, which had to be allowed for in the experiments made with the first-mentioned photometer. The experiments were made with plates of Messrs. Chance’s lighthouse glass, varying in thickness from 6°5 to 24 millimetres, and with Field’s ordinary dense flint, from 7 to 913mm. thick. With Messrs. Chance’s glass the transmitted light ranged from 91°50 to 87:16 per cent., and with the flint-glass from 88:83 to 80:74 per cent. The experiments are incomplete, and are being continued. 9. On an Experiment showing that a Divided Electric Current may be greater in both branches than in the mains. By Lord Rayueicu, D.C.L., LL.D., Sec. B.S. SATURDAY, SEPTEMBER 4. The Section did not meet. MONDAY, SEPTEMBER 6. The following Reports and Papers were read :— 1. Report of the Committee for preparing instructions for the practical work of Tidal Observation.—See Reports, p. 40. 528 REPORT—1886. 2. Fourth Report of the Committee for the Harmonic Analysis of Tidal Observations.—See Reports, p. 40. 3. Report of the Committee appointed to co-operate with the Scottish Meteoro- logical Society in making Meteorological Observations on Ben Nevis.— See Reports, p. 58. 4. Third Report of the Committee appointed to co-operate with Mr. E. J. Lowe in his project of establishing on a permanent and scientific basis a Meteorological Observatory near Chepstuw—See Reports, p. 139. 5. Second Report of the Committee for considering the best means of Com- paring and Reducing Magnetic Observations.—See Reports, p. 64. 6. Third Report of the Committee for considering the best methods of Record- ing the direct Intensity of Solar Radiation.—See Reports, p. 63. 7. The peculiar Sunrise-Shadows of Adam’s Peak in Ceylon. By the Hon. Ratpu Apercromsy, F'.R.Met.Soc. A great peculiarity has been noticed by many travellers about the shadow of Adam’s Peak at sunrise. The shadow, instead of lying flat on the ground, appears to rise up like a veil in front of the spectator, and then suddenly to fall down to its proper level. Various theories have been propounded to account for this, and it has usually been supposed to be due to a sort of mirage. The author, in the course of a meteorological tour round the world, spent a night on the top of the peak, 7,352 feet above the sea, and obtained unmistakable evidencé that the appearance is due to light wreaths of thin morning mist being driven past the western side of the mountain by the prevailing north-east monsoon up a neighbouring gorge. The shadow is caught by the mist at a higher level than the earth, and then falls to its own plane on the ground as the condensed vapour moves on. The appearance is peculiar to Adam’s Peak; for the proper combination of a high isolated pyramid, a prevailing wind, and a valley to direct suitable mist at a proper height on the western side of a mountain, is only rarely met with. Any idea that the appear- ance could be caused by mirage is completely disproved by the author’s thermo- metric observations. Another curious but totally distinct shadow effect is sometimes seen from Adam’s Peak just before and at the moment of sunrise. The shadow of the base of the peak stretches along the land to the horizon, and then the shadow of the summit appears to rise up and stand against the sky. The first part seems to be the natural shadow lying on the ground, and thesky part to be simply the ordinary earth shadow of twilight, so clearly projected against the sky as to show mountainous irregularities of the earth’s surface. As the sun rises the shadow of the summit against the sky gradually sinks to the horizon, and then the ordinary shadow steadily grows shorter as the sun gets higher in the usual manner. The author found a similar effect only at sunset on Pike’s Peak, Colorado. Towards sunset the shadow creeps along the prairie to the horizon, and then begins to rise in the sky till the sun has just gone down, and the anticrepuscular shadow rises too high to catch the outline of the Peak. 8. On the Distribution of Temperature in Loch Lomond and Loch Katrine during the past Winter and Spring. By J. T. Morrison, M.A. The author made observations on the temperature of these lakes on or about TRANSACTIONS OF SECTION A. 529 the term day of each month from December 1885 to June 1886, in continuation of Mr. J. Y. Buchanan’s researches. These included the whole length of Loch Katrine and the head and middle part of Loch Lomond, the deepest sounding, 99 fathoms, being got near Inversnaid in the latter lake. At Inversnaid, from December till March, the water was each month of uniform temperature from surface to bottom, the temperatures being— Dec. 22,1885 . . 42:8° Jan. 21,1886 . . 41-9° Feb. 23,1886 . . 40-05° March 23,1886. . 39:05° In the deepest sounding obtained on Loch Katrine, 79 fathoms, a similar distri- bution was met with up till February, the readings being— Dec. 23,1885 . . (42:3°)! Jan. 22,1886 . . 40-4° Feb. 24,1886 . . 39-0° And, though the maximum density point was thus attained in February, uniformity still prevailed in March down to a depth of 70 fathoms, the readings on March 24 being: surface, 38°1°; 70 fathoms, 38°1°; 79 fathoms, 38:7°. In April the temperature distribution usually found in spring had set in in both lakes, the surface being warmest, the bottom coldest, and the temperature falling more and more slowly with increase of depth. -The circumstance of most interest, however, is that the warmth of the bottom layer increased monthly over the deepest parts of both lakes, as follows :— Mar. April May June Loch Lomond (99 fathoms) . . 39:05° 39:4° 40:38° 40:6° Loch Katrine (79 fathoms) . - og dol 401° "40654 This rise is evidently due not to the conduction of heat nor to the penetration of solar radiation, but to some drainage or oozing causing mixture. This supposition seems necessary also to explain the behaviour of Loch Katrine in March. Drainage en masse appears to occur chiefly in winter and spring, not in summer when the river water and the lake surface water are much warmer than the deep water of the lake. The mean temperature of Loch Katrine probably has a greater range than that of Loch Lomond. The shallower parts of the lakes resemble the deep parts as to uniformity of temperature up till March. But their yearly range is greater. In both lakes the mean temperature becomes uniform along the whole length about April 4. 9. On the Distribution of Temperature in the Firth of Clyde in April and June 1886. By J.T. Morrison, M.A. In the latter parts of April and June of this year Mr. John Murray, Dr. Mill, and the author made serial temperature soundings throughout the Clyde district, chiefly with Negretti and Zambra’s reversing thermometer. It was found that in matter of temperature the waters of the district were divisible into fourgroups: I. North Channel and the plateau south of Arran; II. The Arran and Dunoon open basins; III. The deep sea lochs; IV. The shallow sea lochs. The average temperature in each group at every depth was calculated for April and June, and these averages form the basis of this paper. . In April in all groups there is a deep layer of uniform temperature overlaid by a layer of temperature rising steadily to the surface. In groups II., III., and IV. the uniform deep temperatures are almost the same, about 41:4° F.; in group I. it is 41:8° F, In June the superficial layer of varying temperature had thickened to about 20 fathoms. The deep temperatures in the groups were now very different:— ‘ No sounding made here in December. Above temperature is calculated from that of another part of the lake. 1886. MM 530 REPORT— 1886. 5 BS II. 11. Aig Deep temperature in April, . 41°8° 41°8° 41°5° 41:5° a 2 June. » 467° 48:°90° 43:6° 463° Rise of temperature . : 4 on (40°. 26) aoc To groups III. and IV. analogues are found in a deep and a shallow basin of Loch Lomond, in both of which the bottom temperature rose between April and June. From this it is inferred that land-influences, especially drainage en masse, produce most of the effect noticed in III. and IV. The great rise in the North Channel and southern plateau is evidently due to a warm oceanic current. The rise in temperature in group II. is due to the incoming of warm water from without. As the water between 30 and 765 fathoms in this group is very uni- form in temperature, and as the south plateau is 25 fathoms below the surface, it is supposed that the dense plateau water is carried into the open basins (group II.), and through convection mixes thoroughly the water below 30 fathoms there. Loch Goil is specially remarkable for its isolation and the small rise of bottom temperature—0°6° F. in two months. In Upper Loch Fyne a lenticular mass of water below 43:0° F. was found in June to float between two warmer layers. Its greatest thickness, 30 fathoms, was opposite Inverary. The bottom layer of 44:0° F. was not found to be in con- nection with any equally warm layer either inside or outside of the loch, 10. On the Temperature of the River Thurso. By Hues Roser Mitt, D.Sc., F.R.S.H., F.C.S8. Temperature has been observed since October 1885 twice daily at three points on this the earliest salmon river in the north of Scotland. A shallow feeding lake nine- teen miles from the sea, a point twelve miles from the sea, and one near the river mouth, were selected for observations. At any given time the different parts of the river preserved nearly the same temperature, varying slightly according to the amount of sunshine and direction of the wind. The water cooled down from October to January, and rose steadily in temperature as the season advanced. Diurnal variation was least in January, and increased during each subsequent month. The water, colder than the air at the time of observation during winter, became warmer than it in summer. Shallow water responds more rapidly than air to sun-heating and to chilling by radiation, a fact accountable for by its greater absorbing and conducting powers. The sea was warmer than the river during winter, and cooler than it during summer. Most of the observations discussed were made by Mr. John Gunn, Dale, and Mr. Dayid Gunn, Thurso. 11. On the Normal Forme of Clouds. By A. F. OstEr, F.B.S. The object of this paper is to explain a theory with regard to the principles that may have the greatest effect in producing the Jeading forms that clouds assume. There are doubtless many additional influences that produce or propagate further changes and variations in these forms, but which may be regarded as exceptional or occasional, through frequent disturbances of the regular action herein specially referred to. These remarks will therefore be confined to those influences and conditions that may be regarded as constant and uniform in their effects within certain limits. They are simple and recognised physical causes, varying only in amount and intensity. They may be classed under three heads :— 1st. The diminished specific gravity of the air when more or less charged with invisible vapour. 2nd. The differential horizontal motion of the atmosphere. 1 Average temperature of first few fathoms above bottom. TRANSACTIONS OF SECTION A. 531 8rd. The vertical motion in the atmosphere produced by the heat of the sun’s rays expanding the lower air. The first of these is universally recognised as the initial cause of all clouds, pro- ducing the cwmulus, the firstborn or primary cloud. Its origin is so well under- stood that it is unnecessary to enter on the subject further than is required to make the remarks that follow more intelligible or complete. Water, or moisture on the earth’s surface, is evaporated by the sun’s rays, and enters the adjoining atmosphere. Vapour being specifically much lighter than the air rises more or less rapidly, according to the rate of evaporation. In this climate it has not to ascend to any great elevation before the upper portion arrives in a colder and more attenuated condition of the atmosphere, where it becomes con- densed, but where the lower and flatter portion of the condensed vapour with the uncondensed invisible vapour immediately beneath terminates, it is not possible to say, as a certain amount of the invisible vapour often extends to the earth’s surface. All that can with certainty be asserted is that a large mass or bed of air charged with vapour must exist immediately beneath the newly formed cloud or it could not have risen, an amount of floating power being necessary to lift the condensed vapour or cumulus into a cold atmosphere, where it becomes visible. Yet when it has been so raised the friction of the surfaces of the minute globules of water of which it is composed render them unable to penetrate or force themselves down- wards through the air below, or but very slowly. Itis therefore only in first raising or lifting up the condensed vapour that the floating power of the uncondensed or invisible vapour beneath is required, and not in sustaining it when raised. The invisible vapour, however, that has raised the cumulus or crowning head of condensed vapour, will itself become visible should the atmosphere in which it is travelling become reduced in temperature by any of the cooling influences to which it may be exposed in its travels. The lower atmosphere being always charged with more or less vapour, the eumulus can only be formed when there is so much vapour gerierated as to float above condensation height. Thus far a calm is presumed to prevail. When, however, the atmosphere is in motion its differential horizontal movye- ment produces the first important modification in the form of the cumulus, the height or depth of the lower current varies, and in this climate will generally much more than include the cumulus or condensation height in these latitudes. The friction of the earth from the irregularities of its surface, and the denser state of the lower air, causing it to flow less rapidly than that which is higher and more attenuated, the upper portion of a cloud moves more rapidly than the lower, and the cumulus shears over into a slanting position, and finally assumes the form of the cumulo-stratus, and, however reduced in depth or thickness the cloud may be- come by this flattening and somewhat attenuating process, the cumulus character, though much diminished, is seldom if ever entirely obliterated.1 A young cloud is thus distinguishable from a long-travelled one ; indeed, one that has gone but a short distance is detectable. In this climate a large well-developed cumulus is seldom formed in the cold season, but they are frequent in the summer. The majority of the clouds of the first stage seen in this country are born in warmer latitudes, and come as travelled eumuli, and show more or less the condition of the cumulo-stratus. They may be enlarged or diminished from below, and also diminished or increased in number, according to the heat or dryness or dampness they meet with during their passage over the surface of the earth or sea, but my object is not to treat of cloud genera- tion but only to suggest reasons for certain leading forms they assume after birth. The invisible vapour, however, is subjected to the same changes of form due to 1 Those who have been much on the sea may probably remember occasionally seeing a large flat brown cloud of smoke in the not remote distance, that has been discharged by a previously passing steamer. This came forth from its funnel in great rounded masses far removed from a flat form. The differential action is thus most clearly and simply illustrated in the change that has taken place since its dis- charge, Mu 2 532 REPORT—1886. differential motion previous to its becoming visible, but in this climate it soon rises to the small height at which it is condensed. In summer, when the air is in sufficient motion, and especially in tropical climates, it may travel long distances in its invisible or gaseous state, so that it has time to become elongated by differential action, and when condensed it at once assumes the form of the true stratus, in which case it is not seen as a cumulus or cumulo-stratus at all, When it has risen to condensation height its lines more approach the horizontal, are clearly defined, and the irregularities that would be curves under more rapid decrease of temperature at an earlier stage are seen as elongated lines extending to points as the pure stratus. : We will now leave the lower and denser atmosphere which contains the cumulus, cumulo-stratus, and stratus, and proceed to examine the next stratum above. We here find that a rather rapid change takes place to a drier atmosphere, as was proved by Mr. Glaisher’s investigations regarding the dew-point in his balloon ascents. It is almost like starting from a new globe, and the vapour of this drier air does not become yisible until a higher altitude is attained, where this diminished quantity arrives at its level of visibility. Here the vapour is less dis~ turbed and carried for great distances, so that at the region of this attenuated vapour the cloud is generally level. The cumulus and cumulo-stratus have never reached this elevation, and we have instead the cirro-cumulus and cirro-stratus. The differential movement of the atmosphere, however, though much diminished, is still an important agent in its results, and effects are produced that are not possible in the more bulky and dense clouds of the lowest range. The clouds are, at this higher level, in a highly attenuated condition, and if the globules of vapour are too small in the lower clouds to break through the air that separates them, or even to descend, they are still less capable of doing so at a greater altitude, where they must be still more minute ; but though they can neither coalesce nor descend, they can be spread out gently by the differential action, or if rapidly expanded from beneath, broken up into groups, larger or smaller according to the depth and density of the stratum. Now, suppose the heat of the sun to have caused the lower atmosphere to expand considerably, the effect of it will be to lift up and spread the whole of the superincumbent air, and with it the thin upper stratum of cloud, further from the earth. The result of the vertical elevation or secondary action will be to rend it asunder—the uplifted air becomes more attenuated as it rises, and will spread out in all directions, and the flat cloud we are supposing to exist will of course do the same; but in so doing will be rent into fragments or small groups, and thus produce what is called a ‘mackerel sky,’ just as a similar result is produced, but by the reversed action, in mud that has dried up and shrunk into small patches, while the damp earth beneath remains expanded by the moisture it still contains. Should, however, the expansion in the lower atmosphere take place very slowly, it is possible that the stratum of cloud may remain intact, and not be actually ruptured ; the result would then be to spread out and attenuate the cloud as a whole; all these effects are supposed to take place in a still or very slowly moving atmosphere, but supposing the same conditions take place in an atmosphere in rapid motion or current of air, the tendency will be to elongate the cloud or group of clouds in the direction in which the current is moving, and for this reason: the air is of course going to where it is in demand, it is finding its equilibrium somewhere; that which is nearest the region requiring it will move forward fastest, that which is immediately behind will follow with diminishing velocity, as it is further from the demand, the result being to elongate the stream. Let it be supposed that a thin cloud is in a current, it will have the same elongating influence communicated to ¢—this, if accom- panied with expansion from below, will rupture the cloud into ribs or bars at right angles to the current ; if, however, it is continuous Jut without expansion from below, the reverse action will take place, and longitudinal bars will be formed in the direction of the current. When, however, the main portion of a cloud is in a 1 In tropical or semi-tropical climates where the invisible vaporised moisture travels furthest the stratus is a most striking and important cloud, and is often very conspicuous in the evenings towards sunset as the air becomes cooler, TRANSACTIONS OF SECTION A. 533 stationary state or moving but slowly,and a quicker current catches a portion of it, larger or smaller filaments that may be prominent are drawn out in what are popularly called ‘ mares-tails:’ but this applies more to lower and denser clouds; indeed, it will be observed that the upper stratum of clouds generally is modified by conditions which do not sensibly affect the lower and denser clouds ; their attenu- ated state shows the effects of vertical action as affecting their forms in a striking manner, as well as the influence of varying velocity in horizontal motion. The principal clouds in this latitude come from the 8. W., W., and N. W., and the air from these points moves most rapidly ; the 8. W. is much the fastest as well as the most prevalent. It isa particularly rough and gusty stream, derived from the heated tropical air which rises and is piled up as it were to a great elevation. This as it flows away has to push that which is in advance of it until it has established a stream; the supply of air being more rapid than the outflow or diffusion causes the elastic air to move in irregular gusts or masses, and hence the peculiar violence and lulls alternating in the manner so well known. This stream descends to the surface of the earth in the temperate zone, the latitude varying with the seasons. The more northerly and easterly currents are smooth, flowing to fill up the deficiencies caused by the upward movement of the heated air, or by condensation of vapour, by the fall of rain, or by eddies that carry the lower air into the higher regions of the atmosphere, and by cyclones of various dimensions. The principles here set forth are only applied to ¢wo stratifications of clouds, an upper and a lower one, but of course the same results are obtained in a larger number of strata; it is only for simplicity of description and illustration that no more than two are mentioned.’ 12. On a new Sunshine Recorder. By W. EK. Witson. The instrument consists of two parts, one of which, the indicator, is affected by the sunshine, and the other of which registers the indications. The former, or indicating apparatus, is a differential metallic thermometer, made of a spiral of two metals (zinc and steel) soldered together. Half of the spiral is a right-handed one, and the other half is left-handed. The complete spiral is fixed at its upper end. At its lower end a lever or pointer is attached. The upper half or right-handed portion of the spiral projects through the roof of a ventilated box, and is exposed to the sunshine. The lower or left-handed half is in the shade. Any change in the temperature of the air does not cause the lever or pointer to move, as the upper ’ half of the spiral tends to move it as much in one direction as the lower half tends to move it in the other. When the sun shines on the exposed upper half the lever moves over and completes an electric circuit, which passes through the recording part of the apparatus. The recorder consists of a drum driven by aclock. The drum revolves once in twenty-four hours, and is mounted on an axis with a screw of ten threads to an inch which turns in a nut. This gives the drum a longitudinal motion of 3/’ as well as its motion of rotation. The clock makes an electric contact once every minute, and the electric circuit is led through an electro-magnet which causes a pricker to strike the drum when the circuit is complete. The circuit, as previously mentioned, is led through the lever of the bimetallic indicator, and the circuit is only closed when the sunshine causes the lever to do so. When the circuit is complete the electro-magnet pricks off dots every minute, which represent so many minutes of sunshine. The drum is of such a length that it holds the daily record of sunshine for three months. The instrument also is made to give the total time during which the sun shone in the day. The hands of the clock are not driven by it, but by an electro-magnet which works a ratchet. The electric current is led through this magnet as well as the one that works the pricker, so that as the pricker records minutes of sunshine on the drum, the hands of the clock move forward in intervals of minutes. At the 1 The nimbus, or rain cloud, and all other varieties and combinations, or those under electrical agencies, also eddies or whirl-storms of all sizes, are outside the object of this paper. 534 REPORT—1886. end of the day the clock shows the number of hours and minutes of sunshine for the day. A note is then made of the recorded total, and the hands put back to zero again. The drum is covered with ‘ cyclostyle ’ paper, and after the three months’ record is complete it is removed and put in a frame, under which can be placed ordinary white paper. Printer’s ink is then rolled over it, and a great many copies of the original record can thus be printed for distribution. I think it might be of interest to print several yearly copies on the top of each other on the same paper. By the general resulting degrees of light and shade we should be able to see if there were any periods in the year which were liable to more sunshine than others. 13. Second Report of the Committee for promoting Tidal Observations in Canada.—See Reports, p. 150. 14. Report of the Committee for inviting designs for a good Differential Gravity Meter—See Reports, p. 141. 15. Description of a Differential Gravity Meter founded on the Fleaure of a Spring. By Sir W. Tuomson, LL.D., F.B.S. The design and construction of the instrument now to be described was under- taken on the suggestion of General Walker, of the East Indian Trigonometricai’ Survey. At the Aberdeen Meeting of the British Association in 1885, General. Walker obtained the appointment of a committee to examine into the whole question of the present methods and instruments for the measurement of gravi- tational force, and to promote investigation, having for its object the production of gravitation-measuring instruments of a more reliable and accurate character than. those now in use. The secretary of this committee, Professor Poynting, has already issued a circular note to the members of the committee (of whom the author is one), stating the conditions which must be fulfilled by any gravimeter laid before the committee for examination and report. An instrument, constructed according to the following description, promises to fulfil all the conditions mentioned in Professor Poynting’s circular. Its sensibility is amply up to the specified degree. It is, of necessity, largely influenced by temperature, and it is not certain that the allowance for temperature, or the means. which may be worked out for bringing the instrument always to one temperature, will prove satisfactory. It is almost certain, although not quite certain, that the constancy of the latent zero of the spring will be sufficient, after the instrument has been kept for several weeks or months under the approximately constant stress. under which it is to act in recular use. a ee 7 5 apis fy Eeents peace stares te XM Qo 7rd HHHiAD7 9)nMWdd Front elevation, with one-half of Tube removed. The instrument, which is represented in the accompanying sketch, consists of a thin flat plate of springy german silver of the kind known as ‘doctor,’ used TRANSACTIONS OF SECTION A. 535 for scraping the colouring matter off the copper rollers in calico printing. The piece used was 75 centimetres long, and was cut to a breadth of about 2 centi- metres. A brass weight of about 200 grammes was securely soldered to one end of it, and the spring was bent like the spring of a hanging bell, to such a shape that when held firmly by one end the spring stood out approximately in a straight line, having the weight at the other end. If the spring had no weight the curvature, when free from stress, must be in simple proportion to the distance along the curve from the end at which the weight is attached, in order that when held by one end it may be straightened by the weight fixed at the other end. The weight is about 2 per cent. heavier than that which would keep the spring straight when horizontal ; and the fixed end of it is so held that the spring stands, not horizontal, but inclined at a slope of about 1 in 5, with the weighted end above the level of the fixed end. In this position the equilibrium is very nearly unstable. A definite sighted position has been chosen for the weight, relatively to a mark rigidly connected to the fixed end of the spring, fulfilling the condition that in this position the equilibrium is stable at all the temperatures for which it has hitherto been tested; while the position of unstable equilibrium is only a few millimetres above it for the highest temperature for which the instrument has been tested, which is about 16° C. The fixed end is rigidly attached to one end of a brass tube, about 8 centi- metres diameter, surrounding the spring and weight, and closed at the upper end of the incline by a glass plate through which the weight is viewed. The tube is fixed to the hypotenuse of a right-angled triangle of sheet brass, of which one leg, inclined to it at an angle of about 1/5 radian, is approximately horizontal, and is aprotic’ by a transverse trunnion resting on fixed V’s under the lower end of the tube, with a micrometer screw under the short, approximately vertical, leg of the triangle. The observation consists in finding the number of turns and parts of a turn of the micrometer screw, required to bring the instrument from the position at which the bubble of the spirit-level is between its proper marks, to the position which ~ equilibrates the spring-borne weight, with a mark upon it exactly in line with a chosen divisional line on a little scale of 20 half-millimetres, fixed in this tube in the vertical plane perpendicular to its length. The instrument is, as is to be expected, exceedingly sensitive to changes of temperature, An elevation of temperature of 1° O. diminishes the Young’s modulus of the german silver so much that about a turn and a half of the micrometer screw (lowering the upper end of the tube at the rate of 2/3 millimetre per turn) pro- duces the requisite change of adjustment for the balanced position of the movable weight. About 14 turn of the screw corresponds to a difference of 1 /5000 in the force of gravity, and the sensibility of the instrument is amply valid for 1/40 of this amount ; that is to say, for 1/200,000 difference in the force of gravity. Hence it is not want of sensibility in the instrument that can prevent its measuring differences of gravity to the 1/100,000; but to attain this degree of minuteness it will be necessary to know the temperature of the spring to within 1/20°C. I do not see that there can, be any great difficulty in achieving the thermal adjustment by the aid of a water jacket and a delicate thermometer. To facilitate the requisite thermal adjustment I propose, in a new instrument of which I shall immediately commence the construction, to substitute for the brass tube a long double girder of copper (because of the high thermal conductivity of copper), by which sufficient uniformity of temperature along the spring throughout the mainly effective portion of its length, and up to near the sighted end, shall be secured. The water jacket will secure a slight enough variation of temperature to allow the absolute tem- perature to be indicated by the thermometer with, I believe, the required accuracy. 16. Comparison of the Harcourt and Methven Photometric Standards. By W. Stzpyey Rawsoy, M.A. The author of the paper explained the growing necessity for a reliable govern- 536 REPORT—1 886. mental standard of light, and showed two of the standards to which reference was made in the report of a committee appointed by the Board of Trade in 1881. These were the Harcourt air-gas lamp and the Methven screen. The improvements made in the former since the last meeting of the British Association consisted in an adjustable black background and screen for protecting the eye from the light of all but the upper point of the flame when regulating the height, and thereby enabling the exact height to be determined more accurately ; also in a rack and pinion movement with a scale engraved in millimetres for setting the height of the platinum wire; and besides these an entirely new method of preserving an accurately even rate of drop of pentane for feeding the lamp in the portable form exhibited. his device consists in producing a perfectly constant head by providing an overflow outlet from which the excess of pentane drops into a small bottle, which can be removed when necessary, and emptied into the main reservoir, which is on the top of the lamp, the bottle forming a stopper to the reservoir to prevent evaporation. The rate of drop into the Jamp is regulated with great delicacy by letting the pentane flow down a fine glass tube, in which there is a constricted passage, which can be more or less closed by a fine platinum wire which can be screwed in or out of it by means of a thread working in a cap at the top of the tube. This method is due to Mr. W. F. Donkin. In other respects the lamp remains exactly as described by Mr. Vernon Harcourt at previous meetings of the Association. The Methven screen was one of the form as now constructed, but differing from that upon which the committee on photometric standards reported in 1881. The author showed by a diagram the errors introduced by the alteration of form, amounting to fully 16 per cent. below its normal value. He gave the result of observations made by Mr. W. F. Donkin and himself, _ and showed that the errors may be determined theoretically, and were practically coincident with the result of observations. The value of the Methven varied from 1:687 at 65” to 2:149 at 11”. Observations also showed that the increased thickness of flame subtended by the disc as it approached the slot caused an increase in the value. Allusion was made to experiments for determining the absorption of light by cylindrical glass chimneys, and it was stated that whereas frosted glass absorbs 30-40 per cent. of the light a glass cylinder frosted on the outside only absorbs from 7-16 per cent. 17. Fuel Calorimetry.. By B. H. Tuwarts, F.C.S. Although instruments for the precise estimation of most of the agents of our industries have long ago been introduced, the heating value of coal—the great natural source of power—is rarely tested calorimetrically, even by the largest consumers. At present the different qualities of coals are known as bests, seconds, &c. whereas a calorific estimation might show that the seconds, or even inferior qualities, possessed a higher calorific efficiency than the firsts. By the utilisation of fuel calorimetry a user of coal would be able to ascertain exactly the financial value of different fuels, and to compare the heat energy pos- sessed by the fuel with that economically evolved. Fuel calorimetry would prove a strong inducement to the adoption of more perfect combustion arrangements, and thus aid the laudable objects of the Smoke Abatement Society. The disadvantage of Dulong’s calorimeter, in which the fuel is consumed in a current of oxygen, is that the combustion occupies a considerable time. and conse- quently requires correction for re-cooling ; moreover, unless the oxygen is applied by compression, the instability of carbon dioxide in the presence of carbon prevents 1 See Engineering, November 12, 1886, p. 507. TRANSACTIONS OF SECTION A. 537 the entire oxidation of the carbon, and part of the gases escape as carbon monoxide (CO), with a consequent loss of heat energy, and the measurements are incorrect. In the apparatus of Messrs. Favre and Silbermann the gases resulting from the combustion of fuel are deprived of the carbon dioxide and passed over cupric oxide, for the estimation of the weight of carbon monoxide, but even this modifi- cation does not enable an absolutely exact correction to be made. Mr. Lewis Thompson designed some time ago an ingenious apparatus, in which he obtained the oxygen for fuel combustion from potassium chlorate and potassium nitrate intimately mixed with the fuel in a finely divided condition: the mixture is ignited with a fuse. The dissociation of the potassium chlorate, however, generates heat, and heat is absorbed by the transition of the oxygen from a solid to a gaseous condition ; the dissolution of the residual potassium chloride also absorbs heat, so that con- siderable corrections have to be made. Berthelot mentions that in the hands of Stohmann the solid oxygen arrangement has been greatly improved and increased in accuracy. Berthelot and Vieille finally decided to confine themselves to the use of oxygen in a gaseous form as the oxidis- ing agent in their calorimeter. By the use of gaseous oxygen a single difficulty only has to be overcome—the complete oxidation of the fuel without producing a trace of carbon monoxide or of hydrocarbon. This difficulty is successfully met by com- Pressing oxygen to about seven atmospheres, and with a weight of combustible such that the proportion of oxygen consumed does not exceed 30 or 40 per cent. of its total quantity. The air is forced into the small and strongly formed mortar- shaped vessel by a force-pump. The advantages obtained by this new arrangement are that the calorimetric measurement can be performed in from three to four minutes, whilst the actual combustion occupies only afew seconds, A very small quantity of water is required, so that a high temperature is obtained, thereby increasing the precision, The pro- duct is not found to contain any residual gases, judging from critical analyses. The ignition is effected by passing an electric current through a platinum wire and cage (in which the fuel is placed), With this instrument Berthelot and Vieille have established the calorific value of the most important pyrogenic hydrocarbon compounds, ‘The results are given in the ‘Comptes Rendus’ for May 31, 1886. The only disadvantage of this excellent instrument is its cost; it can be obtained from M. Golas, of Rue St. Jacques, Paris, who makes Berthelot’s splendid instruments of precision. Mr, W. Thomson, of Manchester, has lately improved the Lewis Thompson calorimeter, employing gaseous in preference to solid oxygen, in a very simple manner, and, as far as the author can judge, the instrument appears the most satisfactory for popular use: the combustion is likely to be slightly incomplete owing to the use of oxygen at atmospheric pressure, but for practical purposes the instrument is all that could be desired. The author suggests that the standard marketable value of coal should be ex- pressed in the weight of fuel in decimals of a pound required to raise one pound of water to 212° Fahr. or 100° Centigrade from an initial temperature of (say) 77° Fahr. or 25° Centigrade. 18. On Secular Experiments in Glasgow on the Elasticity of Wires. By J. T. Borromtsry, M.A., F.R.S.E. The object of this paper is to put on record the state of the wires in the secular experiments on stretching of wires commenced under the British Association and with the aid of a money grant. A committee was appointed at the last Glasgow meeting for the purpose of inaugurating these experiments ; and preparations having been made in the interval, the wires were set up in 1879. Several reports have been already made to the British Association, and observations are carried on from time to time on the condition of the wires, which are hung up in the Tower of the University Buildings of Glasgow. 538 REPORT—1886. There are pairs of wires of each of the metals platinum, gold, palladium. These are hung side by side from the same top support, and one of the wires in each pair carries a light load (4, of the breaking weight), the other a heavy load, about 3 of the breaking weight. A comparison is made between the pulling out of the heavily loaded wire and the lightly loaded wire by means of apparatus described in. former Reports. The wires were set up on May 3, 1879. By May 6 they had all come to a fairly steady condition, though the heavily weighted wires were running down to an extent just perceptible from day to day. From May 6, 1879, till August 7, 1880, the running down of the heavily loaded wire in comparison with the lightly loaded wire was in the case of platinum 1:15 mm., on a length of 1553:33 centimetres; in the case of the gold wire 1:45 mm. on 1552°98 centimetres. From August 7, 1880, till March 3, 1886, a further running down has taken place, which amounts in the case of the platinum to 0:40 mm., and in the case of the gold to 0:80 mm. MarHematicaL Sus-SEcTION. 1. Report of the Committee for Calculating Tables of the Fundamental Invariants of Algebraic Forms. 2. On the Rule for Contracting the Process of Finding the Square Root of « - Number. By Professor M. J. M. Hitt. The rule is this: — See ‘ Todhunter’s Algebra,’ Art. 246. When n+ 1 figures of a square root have been obtained by the ordinary method, n ae may be obtained by division only, supposing 2n+1 to be the whole number. After giving the demonstration Todhunter says: ‘ The above demonstration im- plies that N (the number whose square is to be found) is an integer with an exact square root ; but we may easily extend the result to other cases.’ He does not, however, give a general proof of his statement. The object of this paper is to show that the result of the division may exceed by unity the remaining x figures of the square root, and then the rule fails. The proof given in text-books on algebra is applicable to the case when the square root can be exactly obtained as an integer, but not to all other cases. 3. On the Eaplicit Form of the Complete Cubic Differential Resolvent. By the Rey. R. Haruey, F’.R.S.—See Reports, p. 439. 4, On a Geometrical Transformation. By Professor R. W. Grnesz, M.A. Let SP, S’P’ be parallel radii of two circles in opposite directions, then PP’ Fie. 1. passes through a fixed point O on the line of centres SS’ (viz, O is the internal centre of similitude). Let PP’ meet the circles again at QQ’. Then the locus of the intersection of SQ, S’P’ is a conic of foci S, 8’. For in fig. 1 SP=SQ .. RP” =RQ .. S’R-—SR=S’/P’ + SQ =constant (if the circles cut, we find S’7R+SR constant), Now let the circle round S’ become & straight line, S’ passing to infinity. Then any point O on SL (the perpendicular to TRANSACTIONS OF SECTION A. 539 the straight line) may be regarded as the centre of similitude of the circle and Fie. 2. straight line. The changed construction is shown in fig. 2, where P’R is parallel to SO. We have RQ : RP’=SQ : SO=constant =SR : RP’-—SO. Thus R is on a conic, focus S, directrix parallel to LP’. The above suggests the following correspond- ence : Let S, O be two fixed points, XLy a plane per- pendicular to SO (though this restriction may easily be removed). Let P be any point in space, and let-OP meet the plane in X ; then a parallel XP’ to SO meets SP in a Fic. 3 point P’ corresponding to P. peer If P move over a plane, P’ lies on oy another (intersecting the first on the plane i XLy). Therefore if P describe a straight line, P’ describes another. If P lie on a surface, P’ lies on another % of the same degree. The following theorem determines the analysis, viz. :— 80, OL SP SP’ or, if SL beaxis of x; SO0=a;0L=b; 442 =1. xv x =Cos PSO; Hence if x, y, z be co-ordinates of P; x, y’, 2’, of P’ (S being origin), Be ee to A RN Ae te ae oe es ee Thus, the plane le + my +nz=ka is transformed into the plane la’ + my’ + nz’ =k(a’ —b), and so on. If we take SO=OL, the correspondence becomes invyolutional in character, 2.e., if P’ correspond to P, then P will correspond to P’. In that case the point S may be dropped, and we have the following construction :— O is a fixed point, LXX’ a fixed plane; P is any point in space, PX’ perpendicular to plane LX X’; OX’ meets a parallel through X to PX’ in P’. Then P” corresponds to P. Taking O as origin, and co-ordinates as before, we have Z; 8 sa epee ==> e . . - (2) Where d=OL Thus y= max + nd becomes y = nx + md ; Yte=e , yr+d=x?; Yt+e=x ” yt+e=d’; and so on. Since PP’ passes through a fixed point S in OL, we see that perspective projec- 540 REPORT—1886. ‘tion is a particular case of the correspondence, and the formule (2) are probably ‘the simplest obtainable for projection. 5. On the Sum of the nth Powers of the Terms of an Arithmetical Pro- gression. By Professor R. W. Grnesz, M.A. We Imow that n+ 114 2"4+3"+ 2. t= As + lower powers of t n+1 = (#) say. ‘Then (¢+1)"+ (¢+2)"+ ... @4+r)-=(¢+7r)—-(t). Now this statement is true for more than values of t (viz., for all integral values). Therefore it 1s an identity. Putting t= we obtain (a+d)"+(a+2d)"+... +(atrdpnd | o( S47 )-# (3)} A number of interesting results can be obtained from the identity, 6. On a Form of Quartic Surface with twelve Nodes. By Professor Caytey, LL.D., F.R.S. Using throughout capital letters to denote homogeneous quadric functions of the co-ordinates (2, y, z, w), we have as a form of quartic surface with eight nodes Q=(*U,V,W)*=0; viz., the nodes are here the octad of points, or eight points of intersection of the quadric surfaces U=0, V=0, W=0; the equation can be by a linear transformation on the functions U, V,W (that is, by substituting for the original functions re V, W linear functions of these variables) reduced to the form 0 =U? +V? 4+ W?= Suppose now ae the function © can be in a second manner expressed in the like form 2 =P? +Q?+R? (where P, Q, R are not linear functions of U,V,W); fe is, suppose that we have identically U?+ V?+ W*=P*?+Q?+R’, this gives —P?+V?-Q?4 W?-—R’*=0; or, writing U+P, V+Q, W+R=A,B,C, and oo P, V-Q, W—R=E,G,H, the identity becomes AF + BG +CH=0; and this id entity being satisfied, the equation © =0 of the quartic surface may be written in the two forms Q=(A+F)?+(B+G)?+(C+H)*=0, and Q=(A-—F)*+ (B—-G)*?+(C-—H)?=0; viz. the quartic surface has the nodes which are the intersections of the three quadric surfaces A + F=0, B+G=0, C+H=0, and also the nodes which are the intersections of the three quadric surfaces A—F = 0, B-G=0,C—H=0. We may .of course also write the equation of the surface in the form Q=A*+B?+C?+ F’+G?+H?=0. An easy way of satisfying the identity AF+BG+CH=0 is to oe A, B,C, F, G, H=ayz, bzx, cxy, frw, gyw, hzw, where the constants a, 6, ¢, f, g, h satisfy the condition af + bg +ch=0; this being so, the functions A, B, 0, BG, Fy and consequently the functions A + F, B+G,C+H and A—F, B- c 0-H ir of them vanish for the four points (y= 0,z=0, w=0), (¢=0, r=0, w=0), (x y=0,w=0), (v=0,y=0,2=0), or say the points (1,0,0,0), (0,1,0,0), t0.0.1,09, (0,0, 6 ,1) ; it hence appears that the quartic surface Q = ays? + 0272? + Cx?y? + f?2?w? + 9?y?w* + h?2?w* =0 is a quartic surface with twelve nodes; viz. it has as nodes the last-mentioned four TRANSACTIONS OF SECTION A. 541 points, the remaining four points of intersection of the surfaces ayz+frw=0,. bza + gyw =0, cry +hzw=0, and the remaining four points of intersection of the surfaces ayz—fuw =0, bzx —gyw =0, cry —haw =0. The above is the analytical theory of one of the two forms of quartic surface with twelve nodes recently established by Dr. K. Rohn in a paper in the ‘ Abhand- lungen der K. Sichsische Gesellschaft zu Leipzig.’ 7. On the Jacobian Ellipsoid of Equilibrium of a rotating Mass of Fluid. By Professor G. H. Darwin, F.R.S. 8. On the Dynamical Theory of the Tides of Long Period. By Professor’ G. H. Darwin, F.R.S. 9. Note on Sir William Thomson’s Correction of the Ordinary Equilibrium Theory of the Tides. By Professor J. C. Apams, LL.D., F.R.S. In Art. 806 of Thomson and Tait’s ‘Treatise on Natural Philosophy,’ it is pointed out that if the earth’s surface is supposed to be only partially covered by the ocean, the rise and fall of the water at any place, according to the equilibrium theory, would be falsely estimated if, as is usually done, it were taken to be the same as the rise and fall of the spheroidal surface that would bound the water were there no dry land. In the articles which immediately follow the above, it is shown that in order to satisfy the condition that the volume of the water remains unchanged, the expres- sion for the radius vector of the spheroid bounding the water must contain, in addition to the terms which would be sufficient if there were no land, a quantity (a) which depends on the positions of the sun and moon at the time considered, and which is the same for all points of the sea at the same time. This quantity (a) contains five constant coefficients which depend merely on the: configuration of land and water. The values of these coefficients in the case of the actual oceans of our globe have been carefully determined very recently by Mr. H. H. Turner, of Trinity College, in a joint paper by Professor G. H. Darwin and himself, which is published in vol. xl. of the ‘ Proceedings of the Royal Society.’ It should be remarked that every inland sea or detached sheet of water on the globe has in the same way a set of five constants, peculiar to itself, which enter into the expression of the height of the tide at any time in that sheet of water. By taking such constants into account the formulz which apply to the oceanic tides are rendered equally applicable to the tides of such a sea as the Caspian, which are thus theoretically shown to be very small, as they are known to be practically. In the work above cited reference is made to a passage in a memoir by Sir William Thomson on the Rigidity of the Earth, published in the ‘ Philosophical Transactions’ for 1862, as being the only one known to the writers in which any consciousness is shown that such a correction of the ordinary equilibrium theory as. that above mentioned is required. However just this remark may be in reference to modern writers on the equili- brium theory, it is only fair to Bernoulli, the originator of the equilibrium theory, to point out that in his prize essay on the tides he distinctly recognises the fact that when the sea is supposed to have only a limited extent the rise and fall of its surface cannot be the same as if the earth were entirely covered by it. In parti- cular, he shows that the tides are so much the smaller as the sea has less extent in longitude, and thus explains why they are altogether insensible in the Caspian and in the Black Sea and very small in the Mediterranean, of which the communica- tion with the ocean is almost entirely cut off at the Strait of Gibraltar (see Bernoulli, ‘Traité sur le Flux et Reflux de Ja Mer,’ Chapitre XI. section ii. It may be as well to mention that this treatise of Bernoulli, as well as the dis- sertations of Maclaurin and Euler on the same subject, is published in the 3rd volume of the Jesuits’ edition of Newton’s ‘Principia, and also appears in the Glasgow reprint of that edition. 542 REPORT—1 886. 10. On the Determination of the Radius Vector in the Absolute Orbit of the Planets. By Professor GYLDEN. 11. Note on the Orbits of Satellites. By Professor Asapn Haut, [PLATE XI.] The observations of the five inner satellites of Saturn made at Washington since the mounting of the 26-inch refractor in 1873 have been reduced and dis- ‘cussed, and new orbits of these satellites have been determined. It is true that our observations of these satellites are not very numerous, and that further observa- tion will be necessary in order to reach a definitive result. Itshould be stated also that the elliptical figure of this planet and the presence of its ring make it diffi- cult to determine the position of a satellite by means of a filar micrometer in a manner that shall be wholly free from the suspicion of systematic errors. The probable error of one of our measurements is + 0:27’; and I am inclined to think therefore that the Washington observations are as good as any that have been made. The result of our discussion is that the five inner satellites move in orbits whose planes very nearly coincide with the equator of the planet, and the plane of the ring; and also that these orbits are practically circles. The first result is what is generally assumed, but the fact that our observations can be satisfied within the limits of their probable errors by circular orbits seems to me a remarkable one. It would have been interesting of course to have found elliptical orbits, which would have given us the positions of the lines of apsides and their motions, and which would have led to a value of the mass of the ring ; but the circular orbits exclude such results. In the accompanying diagram the orbits of the satellites of Saturn are shown as they would be seen from the pole of the planet’s equator, with the exception of the orbit of Iapetus, which is not correctly drawn, since this orbit is inclined to the plane of projection about 14°, A glance at the diagram will show the relations of the orbits. Thus, beginning at the centre of the planet, the distances to the edges of the ring and to the satellites increase regularly until we reach Rhea. From Rhea to Titan there is a large interval. The orbit of Titan is on the inner edge of the coloured surface, and that of Hyperion is on the outer edge of this surface. This small satellite is so connected with Titan that it may be looked upon as almost a companion of the large satellite. From Hyperion to Iapetus we have a very long interval. It is in these two intervals that one would naturally look for new satellites. But what I wish now to call especial attention to is the fact of the circular orbits of the five inner satellites. In this connection we may notice that the orbit of the satellite of Neptune, those of the four satellites of Uranus, and also those of the three inner satellites of Jupiter are likewise all circular. The orbit of the outer satellite of Mars is very nearly circular. As for the orbit of the inner satellite of this planet, the discussion of my observations of 1877 gave an eccentricity 0:0321, which seemed real; but the recent discussion of my observations of 1879 has dimi- nished this eccentricity, and indicates that this orbit also must be nearly circular. The observations of 1879 are better, I think, than those of 1877, since although the satellite was fainter in 1879, the disc of the planet was so much smaller that the measurements were not so liable to systematic errors which might produce a spurious eccentricity. In the table on next page I have collected the distances and eccentricities of the satellites of our solar system. The distances are expressed in equatorial radii of the primary planets. This table shows that Hyperion has the largest eccentricity, but this satellite is connected with Titan in such a manner that it may be considered an exceptional case. Generally it appears that the satellites with small distances have also very small eccentricities. To this it may.be objected that such a result depends partly on the difficulty of determining for the small distances a good definite value of the eccentricity. ‘There is some ground for such an objection, since in this case small $6" Report Brit. Assoc. 1886 Plate X@ Orbit of Iapetas Spottiswoode &C° Lath. London . Mastrating Professor Asoph Halls Note on the Orbits of Satellites TRANSACTIONS OF SECTION A. 543 errors in the measurements would have a greater influence on the eccentricity ; but in nearly every case the observations are now so numerous, and have been made by so many observers, that the results given in the table must be nearly correct. Planet Satellite Distance Eccentricity Earth , : : . | Moon . : ‘ ; 60°253 0:0549 Mars . . : . | Phobos E ; ; 2-756 0:0066 > ae : ; . | Deimos : : : 6°885 0:0057 Jupiter . : ria pe . - ? : 6-046 0:0000 PAA... «gee finals sothot « 9-628 0:0000 » 8 ‘ : S| 00 ee - : : 15°372 0:0013 4 - : ey le ist hie : . : 27:023 0:0073 Saturn, ‘ ; . | Mimas : : || 3°348 0:0000 op : . . | Enceladus . ; : 4-312 0:0000 pre ta = 5 . | Tethys : : : 5°333 0:0000 ast ite 2 ; . | Dione . : ieeaeass 6837 0:0000 oe : : . | Rhea . - 4 ; 9°560 0:0000 Pay 5 : . | Titan . : : : 22°156 0:0284 ars : . | Hyperion . : , 26°837 01000 sss : E . | Iapetus : t | 64:681 0:0278 Uranus . : =f Atel: * : : é 7508 0-0000 ee 2 : .| Umbriel_ . : ; 10-473 0:0000 a - : . | Titania : : ; 17°161 0:0000 By ey 2 . - | Oberon A : : 22-902 0:0000 Neptune . : . | Satellite . 5 : 12°754 0:0000 It is my purpose to call attention to the relations between the distances of the satellites and the eccentricities of their orbits, because su¢h relations may throw some light on the generation of these systems. Although we may gain but little, yet the facts acquired will serve to test and control the: various hypotheses that are brought forward on this obscure but interesting question. I will venture but one suggestion. If we suppose the satellites with the smaller distances to have formerly moved in a resisting medium, and denote by ¢ the time, e the eccentricity, and k a constant, there will be a secular term in the motion of a satellite of the form — ket, Such a term would tend to destroy the eccentricity of the orbit. 12. Diagrammatic Representation of Moments of Inertia in a Plane Area. By Aurrep Lopes, VA.) The object of the paper is to give a simple construction for measuring the moments and products of inertia about any pair of rectangular axes through a point O of a plane section, and for finding the principal axes at the centre of area of the section, having been given the moments and product of inertia about any other pair of rectangular axes through the point O, +¥, and the position of the centre of area. Two alterna- tive methods are given, the first dealing with the radii of gyration and with the product of inertia divided by the area of the section, the second dealing with the moments and products of inertia directly, either containing the area of the section as a factor or not, as most convenient, I. Let OX, OY be the given axes about a point O in the section, PA the radius of gyration about OX, the area of the rectangle OAPC =the product of inertia (after division by the area of the section), and AQ the radius of gyration about OY. Bisect PQ in S, and with centre S and 1 See Phil, Mag. for November 1886. 544 REPORT—1886. radius SO describe the circle AKL, cutting in K, L any other pair of rectan- gular axes OK, OL which pass through O, Then PK, QK are the radii of gyration about OK, OL respectively, and twice the area of the triangle PKQ is the product of inertia about them. In particular, if PQ be produced to cut the circle in D and E, the principal axes at O are OD, OE. If I is the centre of inertia, draw OK passing through I, and 4x draw IM perpendicular to OI and parallel to OL. Then the product of inertia about IK, IM is equal to that about OK, OL, and is therefore Inown; the radius of gyration about OK is known, and that about IM is also mown, as its square is less than that of the radius about OL by the square of OI. Hence the principal axes at I can be found by a fresh application of the above con- struction or by the construction given below. : Il. OX, OY are the given axes, OA the product of inertia about them, AP the moment of inertia about OX, AQ that about OY, PAQ being in a line parallel to OY, and as drawn in the figure. Bisect PQ in S, with centre S and radius SO describe a circle. If OK, OL are an- other pair of rectangular axes, and K the point where OK cuts the circle, then if KM be drawn perpendicular to PQ, PM, QM are the moments of inertia about OK, OL respectively, and KM is the product of inertia about them. If PQ cuts the circle in D, E, the principal axes at O are OD, OE. TUESDAY, SEPTEMBER 7. The following Reports and Papers were read :— 1. Report of the Committee for reducing and tabulating Tidal Observations in the English Channel, made with the Dover Tide-gauge, and for connect- ing them with Observations made on the French Coast.—See Reports, p. 151. 2. Report of the Committee for constructing and issuing practical Standards for use in Electrical Measurements.—See Reports, p. 145. 3. Report of the Committee on Hlectrolysis—See Reports, p. 308. 4. On an Electric Motor Phenomenon.' By W. M. Morpey. When testing an electric motor in the works of the Anglo-American Brush Electric Light Corporation a phenomenon presented itself which the author at first found some difficulty in explaining. The motor was of the Schuckert-Mordey ‘ Victoria’ type, series-wound, constructed to give 36 horse-power with a current of 20 ampéres. It was supplied with power by a large Brush dynamo. On starting the generator on the occasion in question, the motor, being connected in the circuit, also started, but ran very slowly, and developed but little power. There being apparently some fault in the connections or elsewhere, the circuit was opened in order to stop the motor for the purpose of examination. On breaking the circuit the motor, which at the time was running slowly, stopped suddenly, and instantly started again, running backwards or oppositely to its usual direction, at a rate of 1 This paper was published in eatenso in the Llectrical Review, vol. xix. p. 259 (Sept. 10, 1886), and in other journals. TRANSACTIONS OF SECTION A. 545 speed considerably greater than when it was connected in the circuit, slowly ecreasing in speed until it stopped. An examination showed that its fields had been inadvertently connected as a shunt on the armature instead of in series with it. On joining it up as a series motor it ran without exhibiting any unusual action. The cause of the unexpected reversal under the above-described circumstances will be understood from the following explanation :— As the motor was series-wound, but improperly joined up as a shunt, it will be understood that a strong field was produced, the current through the field- magnet coils being large, the armature being traversed by only a small portion of the total current. It will also be understood that on breaking the external circuit the momentum of the armature converts a shunt motor into a generator, the motion of the arma- ture producing a strong current, circulating in the armature in the reverse direction to the previously received current, but in the fields in the same direction. In fact, a shunt motor under such conditions acts like a series generator with its terminals short-circuited. The intensity of this action in any motor depends to a great extent upon the form of the generating ‘ characteristic’ of the machine. Properly constructed shunt motors, having fields wound to a comparatively high resistance, do not exhibit this action to any marked degree unless a suitable external circuit is provided for them, while shunt motors which are incapable of acting as shunt generators do not exhibit it at all. In the casein question, as the fields were of low resistance, the generation of current was considerable, and instantly stopped the motor. A reference to the figures will show why, when it had stopped, the armature started again in the reverse direction. Fie. 1. Fig. 1 shows the connections and the course of the current when the motor was supplied with current from an external source, and when it was running in its proper ‘ forward’ direction. Fig. 2 shows the direction of current under the two conditions which successively occur when the external circuit is broken. In the first place the momentum of the armature causes a current to be generated which, it will be seen, is in the same direction in the field as before, but in the opposite direction in the armature. This at once stops the armature. Then the momentary induced (‘ extra’) current follows in the same direction at the moment when motion has ceased, and causes the arma- ture to start again in the reverse direction. This extra current is produced in both the armature and the field-magnet coils, but mainly in the latter, as in them the coefficient of self-induction is very considerable. ‘It may be added that the motor in question has for several months been working very suc- cessfully in New Zealand, where it is used to supply power to the machinery at the Phoenix Gold Mine. The current is transmitted to it from generators driven by water power at a con- siderable distance from the mine, the conductor consisting of three miles of copper wire, °165 inch in diameter, supported on telegraph poles. The effective return is over 65 per cent. Referring to the proposed utilisation of the braking power possessed by motors the author pointed out that sudden strains should be avoided, and that the power should rather be wasted in a brake-block, where it did no harm, than in heating the motor itself. The exceptions were those cases where accidents could be pre- vented, or the generated current could be actually used. 1886. NN Fie, 2. 546 REPORT—1886. The author then proceeded to show that the extra current at breaking-circuit was much less in motors than in generators, on account of the opposing E.M.F, in motor armatures. He thought that M. Marcel Deprez had in his recent experi- ments taken needless precautions to avoid the effects of extra currents in his motors, and said that he had frequently opened the circuits of Brush generators giving 2,000 to 3,000 volts and 10 ampéres without in any case doing any harm. 5. On Electric Induction between Wires and Wires. By W. H. Preece, F.R.S. Along the Gray’s Inn Road in London the Post Office has a line of iron pipes buried underground carrying many telegraph wires. The United Telephone Com- pany has a line of open wires along the same route over the housetops situated eighty feet from the underground wires. Considerable disturbances were experi- enced on the telephone circuits, and even Morse signals were read which were said to be caused by the continuous and parallel telegraph circuits. A very careful series of experiments, extending over some period, proved un- mistakably that it was so, and that the well-known pattering disturbances due to induction are experienced at a much greater distance than was anticipated. It became of importance to find out how far these effects could be detected. Experiments conducted on the Newcastle town moor extended the area of the disturbance to a distance of 3,000 feet, while the effects were detected on parallel lines of telegraph between Durham and Darlington at a distance of 10} miles. But the greatest distance experimented upon was between the east and west coast of the Border, where two lines of wire 40 miles apart were affected, the one by the other, sounds produced at Newcastle on the Jedburgh line being distinctly heard at Gretna on a parallel line, though no wires connected the two places. Very careful experiments have shown that these effects are independent of the earth, and are probably inductive effects through the air. Distinct conversation has been held by telephone through the air, without any wire, through a distance of one quarter of a mile ; and this distance can probably be much exceeded. , Effects are not confined to the air, for submarine cables, half a mile apart in the sea, disturb each other. 6. On a Magnetic Experiment. By W. H. Presce, FR. A broken bit of needle was discovered in a hand by a strongly magnetised and. delicately suspended needle when no indications were given by an induction~ balance. . 7. On a new Scale for Tangent Galvanometer. By W. H. Preece, F.R.S., and H. R. Kempe. The instrument is‘ slewed’ around, so that the piane of the coil makes an angle of 60° with the meridian, instead of coinciding with the meridian, and this point is taken as zero, whence a scale in tangent divisions is drawn, coincident with the old scale of tangent-divisions when the zero and the meridian agree. This renders the instrument far more sensitive to increments of current for high deflexions, while the divisions are still proportional to the current strength. 8. On Stationary Waves in Flowing Water.} By Sir Witu1am THomson, LL.D., F.B.S. The subject includes the beautiful wave-pattern produced by a steamer under way in smooth water. But the communication to the Section was limited to another interesting and well-known phenomenon, the rippling of the surface of a natural rivulet, or of the water flowing in a mill-stream, or through a conduit of any 1 For the full paper see the Phil. Mag. for October 1886 and the succeeding months. TRANSACTIONS OF SECTION A. 547 kind. The dynamical theory of the steady motion observed in all such cases was explained to the Section, 9. Artificial Production and Maintenance of a Standing Bore. By Sir Wititam Tuomson, LL.D., F.R.S. 10. Velocity of Advance of a Natural Bore. By Sir Wiu1Am Tuomsoy, LL.D., F.R.S. 11. Graphical Illustrations of Deep Sea Wave-groups. By Sir Wiiu1am Tuomson, LL.D., F.RS. 12. Sir William Thomson’s Improved Wheatstone’s Rheostat. By J.T. Bortomiry, M.A., F.R.S.E. ‘Wheatstone’s rheostat was invented over forty years ago; but, though admirable in conception, and commonly shown on the lecture-table in explaining the nature of and illustrating electric resistance, it is scarcely if at all used in the laboratory, This is altogether owing to practical defects in the instruments as commonly con- structed. The wire comes loose, the contacts are uncertain, and, the current being incessantly broken and made again, the galvanometer needle is perpetually swinging about, instead of showing, as it ought, a continuously increasing or diminishing deflection when the resistance is wound out of the circuit or wound into it. Modifications of the original instrument have been made from time to time, and a very important improvement was recently introduced by Mr. Jolin, of Bristol. In Jolin’s rheostat a toothed-wheel fixed on one of the two cylinders gears into a toothed wheel on a shaft carrying the other cylinder, and a spring fixed to this shaft acts on the last-named cylinder, which surrounds it, on the principle of the mainspring of a watch. By this arrangement the wire is kept tightly stretched, and the barrels can be turned both forwards and backwards by means of a handle attached to one of them. Thus the necessity of shifting the handle from one to the other when the motion is to be reversed is obviated. In Sir William Thomson's improved rheostat the spiral groove in the non- conducting cylinder of previous instruments is dispensed with, and the wire is guided between the cylinders so as to be laid on them spirally by means of a travel- ling nut on a long screw. The screw is turned by the handle and carries a toothed- wheel which gears into two toothed-wheels, one of which turns one of the cylinders, and the other the axial shaft of the other cylinder containing the watch-spring. The guiding nut is also arranged to stop the motion of the screw-shaft at each end NN 2 548 REPORT— 1886. of the range, and so prevent the possibility of overwinding. It also carries an index which moves along a graduated scale and counts the turns of the wire on the insulating cylinder. . In Jolin’s rheostat, as already described, the two cylinders are geared together directly, and turn in contrary directions, the wire passing from the upper side of one to the under side of the other. In Sir William Thomson’s instrument, as is seen in the diagram, the toothed-wheels of the two cylinders are turned in the same direction by the wheel on the screw shaft, and the wire passes horizontally from the top of one cylinder to the top of the other. The conducting cylinder and the wire are both of platinoid, a metallic alloy having properties which make it specially suitable for the purpose. It has very high electric resistance, very small temperature variation of resistance, and it remains with its surface almost or altogether untarnished in the air. On account of the last-named property the contact between the wire and the conducting cylinder is as perfect as can be desired ; and continuity of action, which was a great diffis culty in the old form of the instrument, is absolutely complete. 13. Description of Experiments for determining the Electric Ltesistance of Metals at High Temperatures. By J. T. Borromury, M.A., F.R.S.E. This paper gives an account of apparatus and experiments for the purpose of determining the electric resistance of certain platinum wires at temperatures varying from 0°C. up to the temperature of dull redness, or even a little higher. The wires experimented on were wires which have been used and are in use in an investiga- tion on heat radiation at different temperatures in vacuum, and in air and other gases. The necessity for knowing with accuracy the rate of variation of electric resistance with temperature of the wires was explained in previous communica- tions (1884 and 1885) to Section A of the British Association. The variation of electric resistance of platinum with temperature differs so much in different speci- mens that it is necessary to determine its value for each particular wire which is used in the investigation just referred to. The principal apparatus described are an air-thermometer and a copper heating jacket ; but a somewhat detailed account is also given of other heating apparatus employed, and of the electrical arrangements. The air thermometer used is formed from a piece of thin glass tube from 3 in, to } in. in internal diameter. This is allowed to fall in before the blowpipe and drawn out to a capillary tube at each end; and one of the ends (a) is conveniently turned up along the side of the bulb. The length of the bulb is from 2 in, to 23 in. The thermometer is filled with perfectly dry pure air with the help of an aspirator, and the capillary tube @ is closed by drawing off a small portion by means of a finely pointed blowpipe flame, care being taken that the blowpipe flame does not play on the open end, which might contaminate the air within. When a number of these bulbs are made and filled at one time, the end 0 is also closed, after the filling with pure air, and the thermometers are then ready for use. When the thermometer is to be used it is placed in position, and very soon after the heating commences the end 6 of the capillary tube is opened with a file. When the bulb has taken the temperature which is to be measured, a hand blowpipe is brought and 4 is closed again. The thermometer having been removed from the hot space, it is allowed to cool, is carefully cleaned, if need be, and is then weighed. The weighing so obtained (after a small correction for air contained which it is usually unnecessary to apply) gives the weight of the glass. The thermometer is then immersed under mercury or water which has been boiled and cooled (water is preferred by the author for reasons stated), and the extremity of the capillary tube a is cut off with a glass-knife. The water entering fills the space with the exception of that occupied by the air which was left in the thermometer at the high temperature. A second weighing is then taken. Lastly the end 6 is opened and the thermometer is filled with water, and a third weighing taken. The small portions of glass cut off are of course weighed with the thermometer, and care is taken as to drying the outside of the thermometer for weighings 2 and 3, The TRANSACTIONS OF SECTION a. 549 barometer is also read at the closing and at the opening of the thermometer, and the temperature of the water used is noted, Also the observed barometric pressure at opening is corrected for vapour pressure when water is used, care being taken to ensure, as faras may be done, that the air left in the thermometer is saturated with moisture, though the experiment is carried through with tolerable quickness to avoid loss of air by absorption in the water. Weighing No. 1 being subtracted from weighing No. 3, the whole volume of the thermometer (which must be corrected for expansion of the glass) is obtained. Weighing No. 2 being subtracted from weighing No. 3, the volume of the air at the high temperature is obtained. From the ratio of these two volumes the tempera- ture is calculated by well-known formulas. For temperatures below redness the thermometers are made of German or somewhat hard English glass; for higher temperatures, of combustion-tubing. A few words will suffice to describe the copper jacket.. It consists of a con- siderable number (eight in the jacket exhibited) of sheet copper cylinders, each having a bottom, put one inside the other. These concentric cylinders fit each other very closely, there being only space for a lapping with a few turns of the thinnest asbestos thread to hold them together and keep an air space of perhaps 2, of an inch. The internal diameter of the innermost cylinder is about an inch. A stopper of woven asbestos closes the open end of the innermost cyiinder and supports the air thermometer and the electrodes, of thick copper, to which the platinum wire to be tested is attached by silver soldering. The platinum wire is in the form of a spiral, with the turns well separated, wide enough in diameter to admit the bulb of the air thermometer. A very powerful Fletcher's ‘solid flame’ burner gives ample heat to raise the whole copper cylinder and its contents to redness. Experiments described have shown that the temperature within the copper cylinder may be kept for any length of time so constant that there is no variation of electric resistance perceptible with exceedingly sensitive electric measuring apparatus, Temperatures lower than 300° C. have generally been determined with the aid of the vapours of liquids of high boiling points. A very convenient series of organic liquids was proposed by Drs. Ramsay and Young two years ago. The determination of the electric resistance of the wire was made by the poten- tial method. An electric series is formed, consisting of a single gravity Daniell, the platinum coil to be tested, a known coil of platinoid on the outside of a large tin vessel filled with cold water (which contains a lump of slaked lime to prevent rusting of the tin vessel), and, lastly, a rheostat to regulate the series. The elec- trodes furnished with spring clips of a high resistance (10,000 ohms) galvanometer are clipped on alternately to the standard coil and the platinum wire under test. 14, On a new Standard Sine-Galvanometer.} By Tuomas Gray, B.Sc, F.R.S.E. The instrument proposed in this paper consists of a tube, the length of which is much greater than its diameter, covered with a single layer of wire, laid on uni- formly all along its length. In the instrument proposed the tube is ten centimetres in diameter and one metre long. The advantages claimed for this arrangement are: the ease with which the constants can be obtained with sufficient accuracy ; the great uniformity of the magnetic field produced at the centre of the coil by a current passing through it ; the ease with which the various details of manufacture work out, and hence its comparative cheapness. The coil is mounted on a vertical axis, the line of which passes through the centre of the axis of the tube, and turns above a horizontal table, to which is fixed a scale of degrees on which the angular position of the coil can be read. Arrange- ments are described by means of which the angular position of the suspended needle can be observed by means of a small telescope fixed in one end of the tube. ? Published in full in the Phil. Wag. for October 1886. 550 REPORT—1886. 15. On Magnetic Hysteresis. By Professor G. Fores, M.A. Professor Ewing’ has made a contribution to the science of magnetism, which has only lately come into the hands of scientific men, but which is certain to lead to an extension of our powers in dealing with applications as well as with the theory of magnetism. Lord Rayleigh has already drawn deductions from it in a paper communicated to the ‘ Philosophical Magazine’ for August 1886. The consequences which I wish to draw from it have reference partly to prac- tical applications, and specially to secondary generators or transformers, and partly to Weber’s molecular theory of magnetism. If a coil of wire carrying an electric current encloses an iron core whose length is at least 400 times its diameter, or which is of a ring shape, the magnetic induc- tion produced at the middle of the bar, or at any part of the ring, is due altogether to the direct action of the electric current, since there is no free magnetism, In this case the magnetic force is proportional to the electric current. A curye may be drawn in which abscisse denote electric current or magnetic force, and ordinates represent magnetic induction. As the magnetic force is increased a curve is traced; but this curve is not retraced as the magnetic force decreases. Ifthe magnetic force reach alternately a positive and a negative maxi- mum a closed curve is traced, the area of which indicates the work done upon the iron core in a cycle of these operations, just as the area of the curve traced by the steam engine indicator measures the work done by the engine in a complete cycle of the movements of the piston-rod. The nature of this curve shows that we cannot express the magnetic induction in terms of the magnetic force alone. It is also a function of the history of the iron in the immediate past. This phenomenon is called magnetic hysteresis. Fig. 1 (taken from Ewing) shows the increase of magnetic induction from zero to a maximum, with increase of magnetic force and the subsequent cycle produced. The arrows indicate the direction in which the curve is traced. If the iron be subjected, during the process of magnetisation, to mechanical shocks, these peculiarities disappear, and thé induction becomes a pure function of the magnetic force. It is generally supposed that the tremors of a dynamo machine prevent the effects of magnetic hysteresis from showing themselves. This may sometimes be the case. It is not always so, In the first model non-commutating dynamo constructed by me the electromotive force did not diminish ten per cent. after the exciting current was reduced to zero. That model consisted of a long cylindrical electromagnet, rotating about its axis, its poles being connected by a soft iron cylinder with closed ends. In secondary generators hysteresis must play an important part. In this case the magnetising force is due to the sum of the two currents in the primary and secondary coils. Now the maximum value of the current in the primary is reached earlier than the maximum of the sum of the two currents, and the maximum of the secondary current later. This fact introduces interesting modifications in the form of the magnetic indicator diagrams of the two circuits, to which I wish to draw attention. I will suppose that the maximum of magnetic induction is coincident in time with the maximum of the algebraical sum of the primary and secondary currents. The phase of the primary current may precede, and the phase of the secondary current may follow, that of the magnetic induction by a value varying from O to5 when T is the period of a complete cycle. The currents are taken as harmonic functions of the time. To transform Ewing's cyclic curve of hysteresis into the corresponding diagram for the primary or secondary circuit whose phase is +a or —a in advance of the phase of induction. Let the maximum abscissa represent the magnetic force due to the maximum current in that circuit, and describe a circle with this abscissa as radius, and the zero of co-ordinates O as centre. Take any point P on Ewing’s curve; draw its ordinate PM. Let this line, produced if necessary, cut the circle inQQ,. This line’ cuts Ewing’s curve in two points PP,. If P be the 1 Phil. Trans. 1885, Part II. TRANSACTIONS OF SECTION A. 551 higher of these points operate on Q, the highest of Q Q,, and contrariwise. Draw OQ’ inclined to OQ at an angle +aor—a. Draw the ordinate Q’ M’, and cut off P’M’=PM. P’ isa point on the new curve corresponding to P on Ewing’s curve, In this manner figures have been drawn for the primary and secondary circuits of a secondary generator for cases where the acceleration and retardation of phase T ares and Z' In all these curves work is done in a complete cycle by the electric circuit on the iron when the curve is traced in a direction contrary to the motion of the hands of a watch, and contrariwise. We can now notice several facts :— (1) In all diagrams for the primary circuit the curves are described in the same direction as Hwing’s curve, showing that it does work on the iron. (2) In both diagrams for the secondary circuit the curve is described in the opposite direction to Ewing’s curve, showing that work is done by the iron on the circuit. (3) When the acceleration of the primary is no work is done by the iron on the primary circuit at any part of the cycle. (4) When the retardation of the secondary is pno work is done by the circuit upon the iron at any part of the cycle. (5) In the diagram for the secondary circuit, if the retardation be the angle corresponding to the abscissa OA, the eurve passes through the origin, and the work done in a cycle is zero (A being the point where Ewing’s curve cuts the axis of abscissee). (6) If the retardation be less than this, work is done in the cycle by the secondary circuit on the iron core. (7) It follows from this that, owing to magnetic hysteresis, the retardation of the secondary current cannot be less than the angle corresponding to the abscissa OA except in so far as it derives energy by direct induction from the primary. In most early attempts to make secondary generators the mutual induction of the primary and secondary coils was very slight, and here the retardation must be at least equal to the angle indicated. These remarks hardly apply to the secondary generator of Gautard & Gibbs, who made it a commercial success mainly by causing the direct mutual induction of the circuits to be a maximum. Lord Rayleigh has pointed out that since the hysteresial dissipation of energy per unit volume of iron is the same whether the magnetic circuit be open or closed, while the total work done on or by the electric circuits is greater with an open magnetic circuit, therefore the most efficient secondary generator is one with an open magnetic circuit. This is true only when hysteresial dissipation is the only cause of the loss of efficiency. It has appeared, however, that in actual secondary generators hysteresial dissipation is but a portion of the cause of loss of efficiency. Resistance of the generator itself is a principal cause, and the loss from this cause varies as the square of the current, and would be much greater with the high currents proposed by Lord Rayleigh for his elongated elliptical iron core than in a secondary generator with a closed iron magnetic circuit. The efficiency which Lord Rayleigh proposes to gain in hysteresial dissipation is proportional to the current, The loss due to resistance is proportional to the square of the current. Throughout this investigation I haye assumed that magnetic induction does not lag behind the magnetic force. The second part of this paper has relation to the molecular hypothesis, This hypothesis as developed by Weber and Maxwell gives no account of hysteresis. Ewing has proposed a further assumption—that a molecule has a friction (not a viscous friction, but what Whewell called stiction) which prevents it from turning until the turning force exceeds a constant value ¢ It seems to me that the fewer assumptions we make the more near to the truth 552 REPORT—1886. are we likely to be. Weber has made the assumption that a constant force tends to restore the molecule to its original position. The simpler assumption seems to be that in ideally soft iron the molecules take up positions depending upon the influence of the others. I suppose that when there is no magnetisation the mole- cules naturally group themselves in pairs with poles of opposite name in juxta- position, and that the value of the resolved part of the magnetic force required to separate them must reach a certain value K before any deflection takes place, and then the deflected molecule sets itself in the direction of the magnetic force. This seems to be a very likely hypothesis for iron of ideal softness. If H be the magnetic force and @ the inclination of the axis of a pair of molecules to the magnetic force, the molecules acted upon and set with their axis parallel to the direction of the force are those for which sin @ is greater than = The number of these varies as the magnetisation. Calling the magnetisation I, we have Tv a 2 I=| a@ sin 6d0 = 5. / IE sin-1K H for magnetising forces less than H = K, I =O, for other values we have H=Kk I=0 = 12K ='55 = 15K ='74 = 50K = "98 =10-:0K = 995 The curve deduced from this has the characteristics of extremely soft annealed iron. The only want of resemblance is the suddenness in the rise of the curve after H has reached the value K. This would doubtless be smoothed by any want of perfect mobility of the molecules such as is involved in Maxwell’s addition to Weber’s hypothesis, which must be taken into account in explaining the behaviour of steel which has no connection with the cause of hysteresis. After a certain magnetisation is attained the magnetisation of theiron (if there be no demagnetising influence of ends) must retain each molecule in its axial direction, and the demagnetisation cannot commence until a reverse magnetic force is applied. The effects deduced from this hypothesis are the same in character as those deduced from Ewing’s friction hypothesis, but it seems to me that perfect mobility rather than friction is more likely to be the explanation of a property specially possessed by the softest kinds of iron, and I have thought that the hypothesis is at least worthy of consideration. 16. On a new System of Electrical Control for Uniform-motion Clocks. By Howarp Gruss, F.R.S. The two systems of electrically controlled clocks in use for driving astronomical telescopes possess in common some disadvantages. ; 1. At best they can only correct the rate of the clock itself, and have no power to correct any error in the train of wheels between the clock and the endless screw which drives the instrument. 2. The checking apparatus acts on the clock governor itself, altering its rate; and as that portion of the instrument has a considerable vis inertie there is a liability to a slight oscillation in rate after a correction is made. In the new system the author has endeavoured to avoid these disadvantages. The ‘detector’ portion of the apparatus is attached directly, or almost so, to the screw spindle itself, and the acceleration or retardation is effected by the temporary introduction of a differential gearing into the train of wheels between the clock and the screw spindle. TRANSACTIONS OF SECTION A. 553 17. Design for working the Equatorial and Dome of ‘ Lick’ Observatory, California, by Hydraulic Power. By Howarp Gruss, F.R.S. In the case of very large astronomical telescopes it is desirable to relieve the observer as much as possible from the great physical exertion required to work the instrument, dome, observing chair, &c. The author has worked out a system of hydraulic machinery which effects all the necessary operations and at the same time brings them under the complete control of one individual. This was illustrated by a working model in which the hydraulic apparatus was represented by clockwork governed, as in the case of the actual apparatus, by electricity. WEDNESDAY, SEPTEMBER 8. The following Papers were read :— 1. The Advantages to the Science of Terrestrial Magnetism to be obtained from an expedition to the region within the Antarctic Circle. By Staff Commander Errrick W. Creak, R.N., F.R.S.—See p. 98. 2. On Lithanode. By Desmonp G. Firz-GERa.p. It is claimed for this substance that it is the negative element par excellence for voltaic batteries, primary or secondary, and also a perfect anode for the electrolytic separation of the most electro-negative elements, e.g., chlorine. No other substance fulfils all the desiderata for a negative voltaic element, and no other substance that can be generally employed as an anode in electrolysis is unattackable by chlorine. Lithanode is peroxide of lead in a dense, coherent, and highly conductive form, It constitutes a step in the series of inventions, initiated by Planté and continued by Faure, Volekmar, and others, by which the secondary battery has been perfected. By this step local action in the negative element, a defect of all secondary batteries excepting those constructed with lithanode, is entirely precluded. Lithanode is obtained by moulding a plastic mass of oxide of lead with the solution of a salt, such as ammonic sulphate, which is gradually decomposed by the oxide of lead. The effect of the gradual chemical action is to cause the substance to ‘set,’ and to acquire a hich degree of cohesion and hardness. The mass is then electrolytically converted into a peroxide of lead differing from other forms of this substance, and withstands perfectly the processes of ‘ charging’ and ‘discharging,’ however rapidly these may be effected. The advantages attending the use of lithanode in secondary batteries are—l, a permanent negative element; 2, economy of power; and 3, diminished weight. The advantage in commercial processes of electrolysis is that lithanode constitutes a cheap electrode, and the only one not attackable by chlorine. 3. Draper Memorial Photographs of Stellar Spectra exhibiting Bright Lines. By Professor Epwarp C, Picksrina. The spectra of ordinary stars, whether examined directly by the eye or indirectly by means of photography, present little variety. The comparatively few cases of deviation from the usual type are therefore particularly interesting, and the occurrence of bright lines in a stellar spectrum constitutes perhaps the most singular exception to the general rule. The brightness of the F line in the spectra of yCassiopeiz and 8 Lyre was noticed by Secchi. Rayet afterwards found three rather faint stars in Cygnus, the light of which was largely concen- trated in bright lines or bands. The adoption at Harvard College Observatory of 554. REPORT— 1886. a system of sweeping, with a direct-vision prism attached to the eyepiece of the equatorial telescope, resulted in the discovery by the present writer of several additional objects of the same class. Still more recently Dr. Copeland, during a. journey to the Andes, has extended the list by the discovery of some similar stars in the southern heavens. Among the photographic observations which have been undertaken at Harvard College Observatory, as a memorial to the late Professor Henry Draper, is included a series of photographs of the spectra of all moderately bright stars visible in the latitude of the observatory. A recent photograph of the region in Cygnus previously known to contain four spectra exhibiting bright lines has served to bring to our knowledge four other spectra of the same kind. One of these is that of the comparatively bright star P. Cygni, in which bright lines, apparently due to hydrogen, are distinctly visible. This phenomenon recalls the circumstances of the outburst of light in the star T. Coronze, especially when the former history of P. Cygni is considered. According to Schénfeld it first attracted attention as an. apparently new star in 1600, and fluctuated greatly during the seventeenth century, finally becoming a star of the fifth magnitude, and so continuing to the present time. It has recently been repeatedly observed at Harvard College Ob- servatory with the meridian photometer, and does not appear to be undergoing any variation at present. Another of the stars shown by the photograph to have bright lines is D.M. + 37° 3821, where the lines are unmistakably evident, and can readily be seen by direct observation with the prism. The star has been overlooked, however, in several previous examinations of the region, which illustrates the value of photography in the detection of objects of this kind. The other two stars first shown by the photograph to have spectra containing bricht lines are relatively inconspicuous. The following list contains the desig- nations, according to the Durchmusterung, of all eight stars, the first four being” those previously Imown: 35° 4001, 35° 4013, 86° 3956, 36° 3987, 37° 3821, 88° 4010, 37° 3871, 35° 8952 or 3953. Of these 37° 3871 is P. Cygni, and 37° 3821 is the star in the spectrum of which the bright lines are most distinct. 4. An Apparatus for determining the Hardness of Metals. By Tuomas Turyer, 4.R.S.M. Hitherto there have been but few attempts to quantitatively determine the relative hardness of metals. The method adopted by the United States Govern- ment in 1856 consisted in the punching of a hole by a tool in the form of a pyramid and under a constant pressure. The indentation was carefully measured,. its capacity calculated, and in this way relative hardness was expressed. But it: has been shown that the results obtained really depended in part upon tenacity, and so were not accurate representations of hardness. In 1859 Calvert and John- son employed a modification of the same method, which was further improved by Bottone in 1873. The apparatus recommended by the author is an adoption of the method which has already been employed in determinations of the hardness of minerals, namely, by scratching the surface with a weighted diamond. The diamond is attached to. a gvaduated beam arranged so as to allow of motion in both a horizontal and a vertical plane. By means of a sliding weight, sufficient pressure is applied to cause a distinct scratch on drawing the diamond over a smooth surface of the metal to: be tested. The weight is then moved until the diamond just ceases to produce a visible scratch, when the position of the weight on the scale is observed. Some experience is necessary in observing the scratch, but when this has been obtained! the apparatus gives uniform results. The author's experiments with cast iron have shown the common idea that hardness and tenacity necessarily accompany each other to be erroneous. Very soft cast iron can be obtained with a high tensile strength, while hard cast-iron has. very often a low tensile strength. When metal has to be worked, unnecessary’ TRANSACTIONS OF SECTION A. 555 hardness leads to useless expenditure of power and tools, and in such circum- stances a soft metal is much to be desired. The apparatus is intended to be used in connection with tensile tests of the metal, and in this way affords valuable information as to the mechanical properties of the material. 5. On Star Photography. By Isaac Roverts, F.R.A.S., F.G.S. During the past eighteen months I have been at work taking photographic negatives with a twenty-inch silver on glass reflector for the purpose of mapping the stars in the northern hemisphere, between the pole and the equator, and up to the present time about four hundred plates, each covering four square degrees of sky, inclusive of overlap, have been secured between the pole and declination fifty- seven degrees. The extent of the work done would have been much greater if the weather had permitted. The negatives are exposed for fifteen minutes, which is sufficient time to show very faint stars, the magnitudes of which have not yet been determined. Stars of the ninth magnitude are photographed faintly in one second. Recently I received from Admiral Mouchez, the Director of the Paris Observa- tory, four magnificent enlarged photographs of stars in the constellation Cygnus taken with the 13-inch refractor made by MM. Henry. The negatives were taken one in June and three in August last year, and I deemed it desirable to direct my 20-inch reflector on to the same sky spaces, and take negatives at the corre- sponding time this year, with similar duration of exposures, namely, sixty minutes each, so as to enable comparisons to be made between the results obtained with two instruments constructed on different principles and with unequal apertures. The five photographs which were exhibited are the result. Those marked Nos. 1 and 2 have R 21" 2™, and Declination + 38° 12’, one being exposed for thirty-four minutes, and the other for sixty minutes. No. 3 has R 19> 45™, and Declination + 35°30’. No. 4 has R 19® 55", and Declination + 37° 45’.. No. 5 has R20" 4™, and Declination + 35° 30’. The enlargements have been made to correspond very nearly with MM. Henry’s photographs, and on comparing them with these it will at once be observed that the appearance of the star discs differs. In the Henry photographs the discs are round, with perfectly sharp circumferences, whilst the reflector shows them round,, but with circumferences somewhat undefined, and presenting more the diffraction appearances which always accompany telescopic eye-observations of stars. Another very striking difference is the equal brightness of the Henry star discs. Fifteenth or sixteenth magnitude stars seem as bright as those of first magni- tude, and differ from them only in the diameter of discs, whereas the reflector shows gradations between the brightest and faintest stars that will severely tax the powers of classification. They diminish till they are lost in the colour of the film on the paper, and on the negatives they can be traced to still fainter degrees, and the imagination finds no difficulty in following the diminution till space from our point of view appears to be filled with stars. The reflector also seems to have the advantage over the refractor in the number of stars photographed in a given time; for instance, it I select at random any square inch of surface upon one of the Henry’s plates, and count the stars in it, they number, say, fifty-nine ; but in the same space on my plate they number 109, being in the ratio of nearly two to one. Of course this is a rough mode of making the comparison, but it is the readiest method available at present. The plates which I now submit are not to be considered exceptional or picked, but as average samples of those I can produce on any moderately clear night with the mirror film in an average state of polish. If the photographs numbered 1 and 2 be compared with each other the relative number of the stars which were imprinted on the films with thirty-four and sixty minutes respective exposures may be counted. A photograph of my duplex telescope and observatory at Maghull was also: exhibited. 556 REPORT—1886. 6. Exhibition and Description of Miller’s portable Torsion Magnetic Meter. By Professor James Buiytu. The armature is formed of five small bars of soft iron, 5 mm. long, and weighing 1 gramme. The index wheel has its rim divided into ;+;ths, and carries the outer end of a flat spiral spring, the inner end of which is firmly fixed to the long axis which carries the small armature bars. A fixed pointer projects from the ends of the case across the edge of the disc, and another pointer is fixed to the armature axis. In the normal position the pointers both point to the zero of the scale. When the armatures are placed in a magnetic field they are turned round and are brought back to their zero position by coiling the spring through a definite angle depending upon the strength of the field. A constant is determined for the instrument by experiments in a field of Imown strength, or if necessary it can be empirically graduated. It is hoped that the instrument will be found of service to makers of dynamos for finding the strength of the field in various parts, and also for finding the best forms of pole pieces. There was also exhibited a form of small attraction magnetometer. 7. On the Protection of Life and Property from Lightning.! By W. McGrzcor. The paper proposes the formation of a committee with the following aims and objects :— (a) To travel, and by means of illustrated lectures or papers to awaken general interest in this vital subject. (6) Ina plain journal to publish details of any serious disasters, with pro- fessional opinion in language to be easily understood by the public. (ce) To provide scientific advice and co-operation. (d) To bring about esprit de corps amongst architects, engineers, builders, and manufacturers of lightning conductors. (e) To advise and encourage authorities whose duty it is to protect life and property to employ the means provided by science. (f) To encourage and support insurance companies to insist on employment of these means, and to frame a clause in the policy to enforce proper inspection and testing. (g) To insist upon architects showing the arrangements of metal in buildings, the nature and position of the means adopted for protection against lightning. (2) To investigate (if not already known) the cause why in a general assembly it occurs that men are more frequently killed or injured than women, and why certain localities are more specially selected by lightning. (z) Finally to enable the society, branch, or committee to illustrate to the public the practicability of securing perfect safety at a minimum cost, and +a have the lightning conductors or system of conductors as easily governed and tested as the gas-pipes, and the tests read off as simply and inexpensiyely as the reading of the meter, which can be accomplished by observing the following rules :— (1) Employ none but qualified persons. (2) Avoid extra expense and trouble by having testing-wires fixed at once. (3) Do not grudge an extra length of conductor if required by the nature of the soil near the building. When you are selecting land for cultivation, or soil for certain plants, some trouble is involved ; let the same interest be taken in the spot where the earth terminal is to be laid. ' See also pamphlets by same author on Protection of Life and Property from Lightning and Loss of Life and Property by Lightning, and paper contributed by him to the Bengal Asiatic Society. TRANSACTIONS OF SECTION A. 557 8. An improved Form of Clinometer. By Joun Hopxinson, F.L.S., F.G.S. A ‘day-and-night ’’ compass-card is set to true N. over the compass-needle which necessarily points to magnetic N. The diameter of the card is less than the length of the needle, the points of the needle therefore projecting beyond the card, so that the correction made is seen and can be adjusted when required. The same result would be attained by placing the card below the needle. The clinometer ‘dip’ is as usual below the magnetic needle, and can be easily seen outside the compass-card. The advantage of being able to take the amount and direction of the dip of strata with a single instrument without loss of time and liability to error in making the correction for magnetic deviation, and at the same time having the points of the compass exposed for more minute observation, must be obvious. 558 REPORT—1886. Section B.—CHEMICAL SCIENCE. PRESIDENT OF THE SECTION—WILLIAM Crooxss, F.R.S., V.P.C.S. THURSDAY, SEPTEMBER 2. The PresipEnT delivered the following Address :—- A GLANCE over the Presidential Addresses delivered before this Section on former occasions Will show that the occupiers of this chair have ranged over a fairly wide field. Some of my predecessors have given a general survey of the progress of chemical science during the past year; some, taking up a technological aspect of the subject, have discussed the bearings of chemistry upon our national industries ; others, again, have passed in review the various institutions in this country for teaching chemistry ; and in yet other cases the speaker has had the opportunity of bringing before the scientific world, for the first time, an account of some important original researches. On this occasion I venture to ask your attention to a few thoughts on the very foundations of chemistry as a science—on the nature and the probable, or at least possible, origin of the so-called elements. If the views to which I have been led may at first glance appear heretical, I must remind you that in some respects they are shared more or less, as I shall subsequently show, by not a few of the most eminent authorities, and notably by one of my predecessors in this chair, Dr. J. H. Gladstone, F.R.S., to whose brilliant address, delivered in 1883, I must beg to refer you. Should it not sometimes strike us, chemists of the present day, that after all we are in a position unpleasantly akin to that of our forerunners, the alchemists of the Middle Ages? These necromancers of a time long past did not, indeed, draw so sharp a line as do we between bodies simple and compound; yet. their life-task was devoted to the formation of new combinations, and to the attempt to transmute bodies which we commonly consider as simple and ultimate—that is, the metals. In the department of synthesis they achieved very considerable successes; in the transmutation of metals their failure is a matter of history. But what are we of this so-called Nineteenth Century doing in our laboratories and our libraries? Too many of us are content to acquire simply what others have already observed and discovered, with an eye directed mainly to medals, certifi- cates, diplomas, and other honours recognised as the fruits of ‘passing.’ Others are seeking to turn the determined facts of chemistry to useful purposes; whilst a third class, sometimes not easily distinguished from the second, are daily educing novel organic compounds, or are racking their ingenuity to prepare artificially some product which Nature has hitherto furnished us through the’ instrumentality of plants and animals. The practical importance of such investigations, and their bearing on the industrial arts and on the purposes and needs of daily life, have been signally manifested during the last half-century. Still a fourth class of inquirers, working at the very confines of our knowledge, find themselves occasionally at least face to face with a barrier which has hitherto proved impassable, but which must be overthrown, surmounted, or turned, if che- mical science is ever to develop into a definite, an organised unity. This barrier TRANSACTIONS OF SECTION B. 559 is nothing less than the chemical elements commonly so called, the bodies as yet undecomposed into anything simpler than themselves. There they extend before us, ‘as stretched the wide Atlantic before the gaze of Columbus, mocking, taunting, and murmuring strange riddles, which no man yet has been able to solve. The first riddle, then, which we encounter in chemistry is, ‘ What are the elements?’ Of the attempts hitherto made to define or explain an element none satisfy the demands of the human intellect. The text-books tell us that an element is ‘a body which has not been decomposed’; that it is ‘a something to which we can add, but from which we can take away nothing,’ or ‘a body which increases in weight with every chemical change.’ Such definitions are doubly unsatisfac- tory: they are provisional, and may cease to-morrow to be applicable in any given ‘case. They take their stand, not on any attribute of the things to be defined, but on the limitations of human power ; they are confessions of intellectual impotence. Just as to Columbus long philosophic meditation led him to the fixed belief of the existence of a yet untrodden world beyond that waste of Atlantic waters, so to our most keen-eyed chemists, physicists, and philosophers a variety of phenomena suggest the conviction that the elements of ordinary assumption are not the ultimate boundary in this direction of the knowledge which man may hope to attain. Well do I remember, soon after I had obtained evidence of the distinct nature of thallium, that Faraday said to me, ‘To discover a new element is a very fine thing, but if you could decompose an element and tell us what it is made of— that would be a discovery indeed worth making.’ And this was no new specula- tion of Faraday’s, for in one of his early Jectures he remarked, ‘At present we begin to feel impatient, and to wish for a new state of chemical elements. Fora time the desire was to add to the metals, now we wish to diminish their number. . . . To decompose the metals, then, to reform them, to change them from one to another, and to realise the once absurd notion of transmutation are the problems now given to the chemist for solution.’ Mr. Herbert Spencer, in his hypothesis of the constitution of matter, says :— * All material substances are divisible into so-called elementary substances composed of molecular particles of the same nature as themselves ; but these molecular particles are complicated structures consisting of congregations of truly elementary atoms, identical in nature and differing only in position, arrangement, motion, &c., and the molecules or chemical atoms are produced from the true or physical atoms by processes of evolution under conditions which chemistry has not yet been able to reproduce.’ Mr. Norman Lockyer has shown, I think on good evidence, that, in the heavenly bodies of the highest temperature, a large number of our reputed ele- ments are dissociated, or, as it would perhaps be better to say, have never been formed. Mr. Lockyer holds that ‘the temperature of the sun and the electric are is high enough to dissociate some of the so-called chemical elements, and give us a glimpse of the spectra of their bases’; and he likewise says that ‘a terrestrial element is an exceedingly complicated thing that is broken up into simpler things at the temperature of the sun, and some of these things exist in some sun-spots, while other constituents exist in others.’ The late Sir Benjamin Brodie, in a lecture on Ideal Chemistry delivered before the Chemical Society in 1867, goes even further than this. He says:—‘ We may conceive that, in remote time or in remote space, there did exist formerly, or possibly do exist now, certain simpler forms of matter than we find on the surface of our globe—a, x, &, v, and so on. . . . We may consider that in remote ages the temperature of matter was much higher than it is now, and that these other things existed then in the state of perfect gases—separate existences—uncombined. .. . We may then conceive that the temperature began to fall, and these things to com- bine with one another and to enter into new forms of existence, appropriate to the circumstances in which they were placed. . . . We may further consider that, as the temperature went on falling, certain forms of matter became more permanent . and more stable, to the exclusion of other forms. . . . We may conceive of this process of the lowering of the temperature going on, so that these substances, 560 REPORT— 1886. when once formed, could never be decomposed—in fact, that the resolution of these bodies into their component elements could never occur again. You would then have something of our present system of things. . . ‘Now this is not purely an imagination, for when we look upon the surface of our globe we have actual evidence of similar changes in Nature. .. . When we look at some of the facts which have been revealed to us by the extraordinary analyses which have been made of the matter of distant worlds and nebule, by means of the spectroscope, it does not seem incredible to me that there may even be evidence, some day, of the independent existence of such things as y and ».’ In his Burnett Lectures ‘On Light as a Means of Investigation,’ Professor Stokes, speaking of a line in the spectrum of the nebule, says:—‘ It may possibly indicate some form of matter more elementary than any we know onearth. There seems no @ priori improbability in such a supposition so great as to lead us at once to reject it. Chemists have long speculated on the so-called elements, or many of them, being merely very stable compounds of elements of a higher order, or even perhaps of a single kind of matter.’ In 1868 Graham wrote of Sir W. Thomson's vortex-ring theory, as enlivening ‘matter into an individual existence and constituting it a distinct substance or element.’ From these passages, which might easily be multiplied, it plainly appears that the notion—not necessarily of the decomposability, but at any rate of the com- plexity of our supposed elements—is, so to speak, in the air of science, waiting to take a further and more definite development. It is important to keep before men’s minds the idea of the genesis of the elements; this gives some form to our conceptions, and accustoms the mind to look for some physical production of atoms, It is still more important, too, to keep in view the great probability that there exist in Nature laboratories where atoms are formed and laboratories where atoms cease to be. We are on the track and are not daunted, and fain would we enter the mysterious region which ignorance tickets ‘Unknown.’ It is for us to strive to unravel the secret composition even of the so-called elements—to undauntedly persevere—and ‘still bear up right onward.’ If we adopt the easy-going assumption that the elements, whether self-existent or created, are absolutely and primordially distinct; that they existed as we now find them prior to the origin of stars and their attendant planets, constituting, in fact, the primal ‘ fire-mist, we are little, if any, the wiser. We look at their number and at their distinctive properties, and we ask, Are all these points acci- dental or determinate? In other words, might there as well have been only 7, or 700, or 7,000 absolutely distinct elements as the 70 (in round numbers) which we now commonly recognise? The number of the elements does not, indeed, com- mend itself to our reason from any @ priori or extraneous considerations. Might their properties have conceivably differed from those which we actually observe ? Are they formed bya ‘fortuitous concatenation,’ or do they constitute together a definite whole, in which each has its proper part to play, and from which none could be extruded without leaving a recognisable deficiency ? If their peculiarities were accidental it would scarcely be possible for the ele- ments to display those mutual relations which we find brought into such prominent light and order in the periodic classification of Newlands, Mendeleeff, and Meyer. Has not the relation between the atomic weights of the three halogens, chlorine, bromine, and iodine, and their serially varying properties, physical and chemical, heen worn nearly threadbare? And the same with the calcium and the sulphur groups? Surely the probability of such relations existing among some 70 bodies which had come into fortuitous existence would prove to be vanishingly small! We ask whether these elements may not have been evolved from some few antecedent forms of matter—or possibly from only one such—just as it is now held that all the innumerable variations of plants and arimals have been developed from fewer and earlier forms of organic life? As Dr. Gladstone well puts it, they ‘have been built up one from another, according to some general plan.’ This building up, or evolution, is above all things not fortuitous: the variation and TRANSACTIONS OF SECTION B. 561 development which we recognise in the universe run along certain fixed lines which have been preconceived and foreordained. To the careless and hasty eye design and evolution seem antagonistic; the more careful inquirer sees that evolution, steadily proceeding along an ascending scale of excellence, is the strongest argu- ment in favour of a preconceived plan. The array of the elements cannot fail to remind us of the general aspect of the organic world. In both cases we see certain groups well filled up, even crowded, with forms having among themselves but little specific difference. On the other hand, in both, other forms stand widely isolated. Both display species that are common and species that are rare; both have groups widely distributed—it might be said cosmopolitan—and other groups of very restricted occurrence. Among animals I may mention as instances the Monotremata of Australia and New Guinea, and among the elements the metals of the so-called rare earths. Now, as these facts in the distribution of organic forms are generally considered _ by biological experts to rank among the weightiest evidences in favour of the origin of species by a process of evolution, it seems natural, in this case as in the other, to view existing elements not as primordial but as the gradual outcome of a process of development, possibly even of a ‘struggle for existence.’ Bodies not in harmony with the present general conditions have disappeared, or perhaps have never existed. Others—the asteroids among the elements—have come.into being, and have survived, but only on a limited scale; whilst a third class are abundant because surrounding conditions have been favourable to their formation and preservation. The analogy here suggested between elements and.organisms is, indeed, not the closest, and must not be pushed too far. From the nature of the case there cannot occur in the elements a difference corresponding to the difference between living and fossil organic forms. The ‘great stone book’ can tell us nothing of extinct elements. Nor would I for a moment suggest that any one of our present elements, however rare, is like a rare animal or plant in process of extinction; that any new element is in the course of formation, or that the properties of existing elements are gradually undergoing modification. All such changes must have been confined to that period so remote as not to be grasped by the imagination, when our Earth, or rather the matter of which it consists, was in a state very different from its present condition. The epoch of elemental development is decidedly over, and I may observe that in the opinion of not a few biologists the epoch of organic development is verging upon its close. Making, however, every allowance for these distinctions, if evolution be a cosmic law, manifest in heavenly bodies, in organic individuals, and in organic species, we shall in all probability recognise it, though under especial aspects, in those elements of which stars and organisms are in the last resort composed. Is there, then, in the first place, any direct evidence of the trarsmutation of any supposed ‘element’ of our existing list into another, or of its resolution into anything simpler ? To this question I am obliged to reply in the negative. I doubt whether any chemist here present could suggest a process which would hold out a reasonable prospect of dissociating any or our accepted simple bodies. The highest temperatures and the most powerful electric currents at our disposal have been tried, and tried in vain. At one time there seemed a possibility at least that the interesting researches of Prof. Victor Meyer might show tne two higher members of the halogen group, bromine and iodine, as entering upon the path of dissociation. ‘These hopes have not been fulfilled. It may be said, in the general opinion of the most eminent and judicious chemists, that none of the phenomena thus elicited prove that even an approach has been made to the object in view. Even if we leave our artificial laboratories and seek an escape from the diffi- culty by observing the processes of the great laboratories of Nature, we feel no sufficiently firm ground. We find ourselves thus driven to indirect evidence—to that which we may glean from the mutual relations of the elementary bodies. Such evidence of great _— value is by no means lacking, and to this I now beg to direct attention. First, we Bs 1886. 00 “ 562 REPORT—1886. may consider the conclusion arrived at by Herschel, and pursued by Clerk-Maxwell, that atoms bear the impress of manufactured articles. Let us look a little more closely at this view. A manufactured article may well be supposed to involve a manufacturer. But it does something more: it implies certainly a raw material, and probably, though not certainly, the existence of by-products, residues, paralei- pomena. What or where is here the raw material? Can we detect any form of matter which bears to the chemical elements a relation like that of a raw material to the finished product—like that, say, of coal-tar to alizarin? Or can we recognise any elementary bodies which seem like waste or refuse? Or are all the elements, according to the common view coequals? ‘To these questions no direct answer is as yet forthcoming. And this leads us up to a hypothesis which, if capable of full demonstration, would show us that the accepted elements are not coequal, but have been formed by a process of expansion or evolution. I refer to the well-known hypothesis of Prout, which regards the atomic weights of the elements as multiples, by a series of whole numbers, of unity =the atomic weight of hydrogen. Everyone is aware that the recent more accurate determinations of the atomic weights of different elements do not by any means bring them into close harmony with the values which Prout’s law would require. Still in no small number of cases the actual atomic weights approach so closely to those which the hypothesis demands that we can scarcely regard the coincidence as accidental. Accordingly, not a few chemists of admitted eminence consider that we have here an expression of the truth, masked by some residual or collateral phenomena which we have not yet succeeded in eliminating. The original calculations on which the most accurate numbers for the atomic weights are founded have recently been recalculated by Mr. F. W. Clarke. In his concluding remarls, speaking of Prout’s law, Mr. Clarke says that ‘none of the seeming exceptions are inexplicable. In short, admitting halfmultiples as legitimate, it is more probable that the few apparent exceptions are due to un- detected constant errors than that the great number of close agreements should be merely accidental. I began this recalculation of the atomic weights with a strong prejudice against Prout’s hypothesis, but the facts as they came before me have forced me to give it a very respectful consideration.’ But if the evidence in favour of Prout’s hypothesis in its original guise is deemed insufficient, may not Mr. Clarke’s suggestion of half-multiples place it upon an entirely new basis? Suppose that the unit of the scale, the body whose atomic weight, if multiplied by a series of whole numbers, gives the atomic weights of the remaining elements, is not hydrogen, but some element of still lower atomic weight ? We are here at once reminded of helium—an element purely hypothetical as far as our Earth is concerned, but supposed by many authorities, on the faith of spectro- scopic observations, to exist in the sun and in other stellar bodies. Most solar eruptions present merely the characteristic lines of hydrogen C, F, and H, and along with them one particular line which at first was classed in the sodium group, but which is a little more refrangible, and is designated by the symbol D,. Ac- cording to Mr. Norman Lockyer and the late Father Secchi, this ray undergoes modifications not comparable to those affecting other rays of the chromosphere. In the corresponding region of the spectrum no dark ray has been observed. That the accompanying lines C, F, and H pertain to hydrogen is evident; and as D, has never been obtained in any other spectrum, it is supposed to belong to a body foreign to our Earth, though existing in abundance in the chromosphere of the sun. To this hypothetical body the name helium is assigned. 4 In an able memoir on this subject, read befure the Academy of Brussels, the Abbé E. Spée shows that, if helium exists, it enjoys two very remarkable properties. Its spectrum consists of a single ray, and its vapour possesses no absorbent power. The simple single ray, though I believe unexampled, is by no means an impossible ~ phenomenon, and indicates a remarkable simplicity of molecular constitution. The non-absorbent property of its vapour seems to be a serious objection to a general physical law. Professor Tyndall has demonstrated that the absorptive power TRANSACTIONS OF SECTION B. 563 increases with the complexity of molecular structure, and hence he draws the con- clusion that the simpler the molecule the feebler the absorption. This conclusion the Abbé Spée regards as perfectly legitimate; but it neither explains nor even necessitates the absence of all absorptive power. Granting that helium exists, all analogy points to its atomic weight being below that of hydrogen. Here, then, we may have the very element, with atomic weight half that of hydrogen, required by Mr. Clarke as the basis of Prout’s law.. But a more important piece of evidence for the compound nature of the chemi- cal elements has yet to be considered. Many chemists must have been struck with certain peculiarities in the occurrence of the elements in the Earth’s crust; it is a stale remark that we do not find them evenly distributed throughout the globe. Nor are they associated in accordance with their specific gravities; the lighter ele- ments placed on or near the surface, and the heavier ones following serially deeper and deeper. Neither can we trace any distinct relation between local climate and mineral distribution. And by no means can we say that elements are always or chiefly associated in nature in the order of their so-called chemical affinities; those which have a strong tendency to form with each other definite chemical combina- tions being found together, whilst those which have little or no such tendency exist apart. We certainly find calcium as carbonate and sulphate, sodium as chloride, silver and lead as sulphides; but why do we find certain groups of elements with little affinity for each other yet existing in juxtaposition or commixture? The members of some of these groups are far from plentiful, not generally or widely diffused, and certainly they are not easy to separate. As instances of such grouping we may mention— 1. Nickel and cobalt, of which it may be said that had their compounds been colourless they would have been long regarded as identical, and possibly even yet would not have been separated. 2. The two groups of platinum metals. 3. The so-called ‘rare earths,’ occurring in gadolinite, samarskite, &c. and evidently becoming more numerous the more closely they are examined. Certain questions here suggest themselves:—Is the series of these elements like a staircase or like an inclined plane? Will they, the more closely they are scrutinised, be found to fade away the more gradually the one into the other ? Further, will a mixture hitherto held to be simple, like (e.g.) didymium, be capable of being split up in one direction only, or in several? I have been led to ask this Jast question because I have separated from didymium bodies which seem to agree neither with the praseodymium and neodymium of Dr. Auer von Welsbach, nor with the components detected by M. de Boisbaudran and M. Demarcay. Why, then, are these respective elements so closely associated? What agency has brought them together ? An eminent physicist evades the difficulty by suggesting that their joint oceur- rence is simply an instance of the working of the familiar principle ‘ Birds of a feather flock together.’ In their chemical and physical attributes these rare earths are so closely similar that they may be regarded as substantially identical in all the circumstances of solution and precipitation to which they may have been exposed during geological ages. But do we, in point of fact, recognise any such agency at work in Nature? Is there any power which regularly and systematically sorts out the different kinds of matter from promiscuous heaps, conveying like to like and separating unlike from unlike? I must confess that I fail to trace any such distributive agency, nor, in- -deed, do I feel able to form any distinct conception of its nature. I must here remark that coral worms in some cases do effect a separation of certain kinds of matter. Thus a Gorgonia of the species Melithea, and Mussa -sinuosa, undoubtedly eliminate from sea-water not merely lime, but even yttria ; and other recent corals, Pocillopora damicornis, and a Symphyllia close to the yttria- secreting Mussa, separate samaria from sea-water. Sea-weeds and aquatic mollusks contain a larger proportion of iodine and bromine than the waters which they 00 2 564 REPORT—1886. inhabit, and may thus be said to separate out these elements from the chlorine with which they are mingled, But if we examine these cases of elimination we see that they are limited in their scope. They extend only to substances existing in solution, of which there is. a fresh supply always at hand, and which are capable of entering into the animal or vegetable economy. Again, the elimination of iodine and bromine, effected as just described, is of a very imperfect character, and, when such water-plants and animals die and decay, their constituents will be again distributed in the water. We cannot well consider that nickel and cobalt have been deposited in ad- mixture by organic agency, nor yet the groups iridium, osmium, and platinum —ruthenium, rhodium, and palladium. Since the earthy metals to which I have referred—such as yttrium, samarium, holmium, erbium, thulium, ytterbium, &c.—are very rare, the probability of their ever having been brought together in some few uncommmon minerals discovered only in a few localities must be regarded as trifling indeed, if we suppose that these metals had at any time been widely diffused in a state of great dilution with other matter. The features which we have just recognised in these earths seem to oint to their formation severally from some common material placed in conditions in each case nearly identical. The case is strengthened by a consideration of the other groups of elements, also similar in properties, having little affinity for each other and occurring in admixture; either all or at least some of the elements con- cerned being moreover decidedly rare. Thus we have nickel and cobalt not plentiful or widely distributed ; cobalt, perhaps, never found absolutely free from nickel, and vice versd. We have also the two platinum groups, where very similar features prevail. A weighty argument in favour of the compound nature of the elements is that drawn from a consideration of the compound radicles, or, as they might be called, pseudo-elements. Their similarity with the accepted elements is perfectly familiar to all chemists. If, for example, we suppose that in some age or in some country men of science were cognisant of the existence and of the behaviour of cyanogen, but had not succeeded in resolving it into its constituents, nothing, surely, would prevent their viewing it as an element, and assigning it a place with the halogens. It may fairly be held that if a body which we know to be compound can be found playing the part of an element, this fact lends a certain plausibility to the supposition that the elements also are not absolutely simple. This line of thought, or at least one closely approximating to it, was worked out by Dr, Carnelley in a paper read before this Association at its last meeting. From a comparison of the physical properties of inorganic with those of organic com- pounds, Dr. Carnelley concludes that.‘ the elements, as a whole, are analogous to the hydrocarbon radicles.’ This conclusion, if true, he adds, should lead to the further inference that the so-called elements are not truly elementary, being made up of at least two absolute elements, named provisionally A and B. Hence, he argues, it should be possible to build up a series of compounds of these two primary elements which would correspond to what we now call elements. Such an arrangement, to be admissible, would have to fulfil certain conditions :—The secondary elements thus generated from A and B must exhibit the phenomena of periodicity, and the series would have to form octaves; the entire system is bound to display some feature corresponding to the ‘odd and even series’ of Mendeleeff’s classification ; the atomic weights must increase across the system from the first to the seventh group; that is, from the positive to the negative end of each series ; the atomicity would have to increase from the first to the middle group, and then either increase or decrease to the seventh group; some feature should appear cor- responding to the eighth group; and, lastly, the atomic weights in such a system ought to agree with the atomic weights as experimentally determined. This last condition Dr. Carnelley rightly regards as the most crucial, and he finds his arrangement gives atomic weights which in a majority of instances coincide approximately with the actual atomic weights. Thus out of a total of sixty-one elements whose atomic weights have been determined with at TRANSACTIONS OF SECTION B. 565 least approximate accuracy, and whose places in the periodic system are not dis- puted, twenty-seven agree almost exactly with the actual numbers, whilst nineteen others are not more than one unit astray. For a detailed consideration of the conclusions which follow from Dr. Carnelley’s views I must refer to his paper as read at our last meeting. Two points bear more especially upon the subject now under consideration—that is, if this speculation on the genesis of the elements is well founded. First, the existence of elements of identical atomic weights, isomeric with each other, would be possible; as such Dr. Carnelley mentions respectively nickel and cobalt (now found to have slightly different atomic weights), rhodium and ruthenium, osmium and iridium, and the metals of some of the rare earths. Secondly, in Dr. Carnelley’s scheme all the chemical elements save hydrogen are supposed to be composed of two simpler elements, A=12 and B=—2. Of these he regards A as a tetrad identical with carbon, and B as a monad of negative weight—perhaps the ethereal fluid of space. Dr. Carnelley’s three primary elements therefore are carbon, hydrogen, and the ether. Starting from the supposition that pristine matter was once in an intensely heated condition, and that it has reached its present state by a process of free cooling, Dr. E. J. Mills suggests that the elements as we now have them are the result of successive polymerisations. Dr. Mills reminds us that chemical substances in the process of cooling naturally increase in density, and, if such increase be measured as a function of time or of temperature, we sometimes observe that there are critical points corresponding to the formation of new and well-defined sub- stances. In this manner, ordinary phosphorus is converted into the red variety, I is transformed into I,, 8, becomes S,, and NO, N,O,. Among organic bodies styrol, in like manner, according to Dr. Mills, is converted into metastyrol, aldehyd into paraldehyd, the cyanates into cyanurates, and turpentine into metatereben- thene. At the critical points above referred to heat is liberated in especial abun- dance, and the bodies thus formed are known as polymers. If we could gradually cooldown substances through a vast range of temperature, we should then pro- bably discover a much greater number of such critical points, or points of multiple proportion, than we have been able to discover experimentally. The heat given out in the act of polymerisation naturally reverses to some extent the polymerisation itself, and so causes a partial return to the previous con- dition of things. This forward and backward movement, several times repeated, constitutes ‘periodicity.’ Dr. Mills regards variable stars as instances, now in evidence, of the genesis of elementary bodies. From a study of the classification of the elements, Dr. Mills is of opinion that the only known polymers of the primitive matter are arsenic, antimony, and perhaps erbium and osmium; whilst zirconium, ruthenium, samarium, and platinum approxi- mate to the positions of other polymers. Hence, from this genetic view, these elements may be described as products of successive polymerisations. I must now call attention to a method of illustrating the periodic law, proposed by my friend Professor Emerson Reynolds, of the University of Dublin, which will here assist us. Professor Reynolds points out that in each period the general pro- perties of the elements vary from one to another with approximate regularity until we reach the seventh member, which is in more or less striking contrast with the first element of the same period, as well as with the first of the next. Thus chlorine, the seventh member of Mendeleeff’s third period, contrasts sharply both with sodium, the first member of the same series, and with potassium, the first member of the next series; whilst, on the other hand, sodium and potassium are closely analogous. The six elements whose atomic weights intervene between sodium and potassium vary in properties, step by step, until chlorine, the contrast to sodium, is reached. But from chlorine to potassium, the analogue of sodium, there is a change in properties per saltum. Further, such alternations of gradual and abrupt transitions are observed as the atomic weights increase. If we thus recognise a contrast in properties—more or less decided— 566 REPORT—1886. between the first and the last members of each series, we can scarcely help admitting the existence of a point of mean variation within each system. In general, the fourth element of each series possesses the properties we might expect a transition- ‘element to exhibit. If we examine a particular period—for instance, that one whose meso-element is silicon, we note:—vrst, that the three elements of lower atomic weight than silicon, viz. sodium, magnesium, and aluminium, are distinctly electro-positive in character, while those of higher atomic weight, viz., phosphorus, sulphur, and chlorine, are as distinctly elect o-negative. Throughout the best known periods this remarkable subdivision is observable, although, as might be anticipated, the differences become less strongly marked as the atomic weights increase. Secondly, that the members above and below the meso-element fall into pairs of elements, which, while exhibiting certain analogies, are generally in more or less direct chemical contrast. Thus, in the silicon period we have— Si” + AY” p77 — + Me” S”— + Na’ CY — This division also happens, in many cases, to coincide with some characteristic valence of the contrasted elements. It is noteworthy, however, that the members on the electro-negative side exhibit the most marked tendency to variation in atom- fixing power, so that valence alone is an untrustworthy guide to the probable posi- tion of an element in a period. Thus for the purpose of graphic translation Professor Reynolds considers that the fourth member of a period—silicon, for example—may he placed at the apex of a symmetrical curve, which shall represent, for that particular period, the direction in which the properties of the series of elements vary with rising atomic weights. _ In the drawing before you (fig. 1) I have modified Professor Reynolds's diagram in one or two points. J have turned it the reverse way, as it is more conyenient to start from the top and proceed downwards. I have represented the pendulous swing as gradually declining in amplitude according to a mathe- matical law, and I have introduced another half-swing of the pendulum between cerium and lead, which not only renders the oscillations more symmetrical, but brings gold, mercury, thallium, lead, and bismuth on the side where they are in complete harmony with members of ‘foregoing groups, instead of being out of har-. mony with them. This modification has another adv: antage, inasmuch as it leaves. many gaps to be hereafter filled in with new elements just when the development. of research is beginning to demand room for such expansion. I do not, however, wish to infer that the gaps in Mendeleeff’s table, and in this graphic representation of it, necessarily mean that there are elements actually existing to fill up the gaps; these gaps may only mean that at the birth of the elements there was an easy potentiality of the formation of an element which would fit into the place. Following the curve from hydrogen downwards we find that the elements forna- ing Mendeleeff’s eighth group are to be found near three of the ten nodal points. These bodies‘are ‘interperiodic,’ both because their atomic weights exclude them from the small periods into which the other elements fall, and because their chemical relations with certain members of the adjacent periods show that they are probably interperiodic in the sense of being transitional. This eighth group is divided into the “three triplets—iron, nickel, and cobalt ; rhodium, ruthenium, and palladium ; iridium, osmium, and platinum. "The members. of each triplet have often been regarded as modifications of one single form of matter. Notice how accurately the series of like bodies fits into this scheme. Beginning at the top, run the eye down analogous positions in each oscillation, taking either the electro-positive or electro-negative swings :— Ni. Bein hi Na so Belles Si Pi iicS oF Clemo V Ca K Cu Zn Ga Ge As Se Br Ti Nb Sr Rb Ag Cd In Sn Sb Te I Zr —) Baws si eS ees, Se ea Ta Au Hg Tl Pb Bi TRANSACTIONS OF SECTION B. 567 Notice, also, how orderly the metals discovered by spectrum analysis fit in their places—gallium, indium, and thallium. The symmetry of nearly all this series proclaims at once that we are working in > Si 2 g o S ~ R o S R = Liven. . . ULO7 17 4 J, ; SS Ba aete os ey eho: Q~7 the right direction. We can also learn much from the anomalies here visible. Look at the places marked with a circle; didymium, samarium, ho!mium, erbium, 568 REPORT—1886. ytterbium, and thulium. Didymium cannot follow in order after the triad nitrogen, vanadium, columbium ; nor erbium follow phosphorus, arsenic, antimony ; nor thulium follow chlorine, bromine, iodine; nor ytterbium follow potassium, rubidium, c#sium. The inference to be drawn is that these bodies are out of place, owing to their atomic weights not having been correctly determined—an inference which is strengthened by the knowledge that the elementary character of some of these bodies is more than doubtful, whilst the chemical attributes of most of them are unknown. 2 The more I study the arrangement of this zigzag curve the more I am convinced that he who grasps the key will be permitted to unlock some of the deepest mysteries of creation.. Let us imagine if it is possible to get a glimpse of a few of the secrets here hidden. Let us picture the very beginnings of time, before geological ages, before the earth was thrown off from the central nucleus of molten fluid, before even the sun himself had consolidated from the original protyle.1 Let us still imagine that at this primal stage all was in an ultragaseous state, at a temperature inconceivably hotter? than anything now existing in the visible universe; so high, indeed, that the chemical atoms could not yet have been formed, being still far above their dissociation-point. In so far as protyle is capable of radiating or reflecting light, this vast sea of incandescent mist, to an astronomer in a distant star, might have appeared as a nebula, showing in the spectroscope a few isolated lines, forecasts of hydrogen, carbon, and nitrogen spectra. P But in coursa of time some process akin to cooling, probably internal, reduces the temperature of the cosmic protyle to a point at which the first step in granula- tion takes place; matter, as we know it, comes into existence, and atoms are formed. As soon as an atom is formed out of protyle it is a store of energy, potential (from its tendency to coalesce with other atoms by gravitation or chemically) and kinetic (from its internal motions). To obtain this energy the neighbouring protyle must be refrigerated by it,> and thereby the subsequent formation of other atoms will be accelerated. But with atomic matter the various forms of energy which require matter to render them evident begin to act ; and, amongst others, that form of energy which has for one of its factors what we now call atomic weight. Let us assume that the elementary protyle contains within itself the potentiality of every possible combining proportion or atomic weight. Let it be granted that the whole of our known elements were not at this epoch simultaneously created. The easiest formed element, the one most nearly allied to the protyle in simplicity, is first born. Hydrogen—or shall we say helium P—of all the known elements the one of simplest structure and lowest atomic weight, is the first to come into being. For some time hydrogen would be the only form of matter (as we now know it) in existence, and between hydrogen and the next formed element there would be a considerable gap in time, during the latter part of which the element next in order of simplicity would be slowly approaching its birth- point: pending this period we may suppose that the evolutionary process which soon was to determine the birth of a new element would also determine its atomic weight, its affinities, and its chemical position. 1 We require a word, analogous to protoplasm, to express the idea of the original primal matter existing before the evolution of the chemical elements. The word I have ventured to use for this purpose is compounded of xpé (earlier than) and San (the stuff of which things are made). The word is scarcely a new coinage, for 600 years ago Roger Bacon wrote in his De Arte Chymie, ‘The elements are made out of #Ay, and every element is converted into the nature of another element.’ 2 I am constrained to use words expressive of high temperature; but I confess I am unable clearly to associate with protyle the idea of hot or cold. Zemperature, radiation, and free cooling seem t> require the periodic motions that take place in the chemical atoms; and the introduction of centres of periodic motion into protyle would constitute its being so far changed into chemical atoms. ’ Iam indebted to my friend G. Johnstone Stoney, F.R.S., for the idea here put forward, as well as for other valuable suggestions and criticisms on some of the theoretical questions here treated of. TRANSACTIONS OF SECTION B. 569 In the original genesis the longer the time occupied in that portion of the cooling down during which the hardening of the protyle into atoms took place, the more sharply defined would be the resulting elements; and, on the other hand, with more irregularity in the original cooling, we should have a nearer approach to the state of the elemental family such as we know it at present. In this way it is conceivable that the succession of events which gave us such groups as platinum, osmium, and iridium—palladium, ruthenium, and rhodium— iron, nickel, and cobalt, if the operation of genesis had been greatly more prolonged, would have resulted in the birth of only one element of these groups. It is also probable that by a much more rapid rate of cooling, elements would originate even more closely related than are nickel and cobalt, and thus we should have formed the nearly allied elements of the cerium, yttrium, and similar groups ; in fact the minerals of the class of samarskite and gadolinite may be regarded as the cosmical lumber-room where the elements in a state of arrested development—the uncon- nected missing links of inorganic Darwinism—are finally aggregated. I have said that the original protyle contained within itself the potentiality of all possible atomic weights. It may well be questioned whether there is an abso- lute uniformity in the mass of every ultimate atom of the same chemical element. Probably our atomic weights merely represent a mean value around which the actual atomic weights of the atoms vary within certain narrow limits. Each well-defined element represents a platform of stability connected by ladders of unstable bodies. In the first accreting together of the primitive stuff the smallest atoms would form, then these would join together to form larger groups, the gulf across from one stage to another would be gradually bridged over, and the stable element appropriate to that stage would absorb, as it were, the un- stable rungs of the ladder which led up to it. I conceive, therefore, that when we say the atomic weight of, for instance, calcium is 40, we really express the fact that, while the majority of calcium atoms have an actual atomic weight of 40, there are not a few which are represented by 39 or 41, a less number by 38 or 42, and soon. We are here reminded of Newton’s ‘ old worn particles.’ Is it not possible, or even feasible, that these heavier and lighter atoms may have been in some cases subsequently sorted out by a process resembling chemical fractionation? This sorting out may have taken place in part while atomic matter was condensing from the primal state of intense ignition, but also it may have been partly effected in geological ages by successive solutions and reprecipitations of the various earths. This may seem an audacious speculation, but I do not think it is beyond the power of chemistry to test its feasibility. An investigation on which I have been occupied for several years has yielded results which to me appear apposite to the question, and I therefore bez permission here to allude briefly to some of the results, reserving details to a subsequent communication to the Section. My work has been with the earths present in samarskite and gadolinite, separat- ing them by systematic fractionation. Chemical fractionation, on which I hope to say more on another occasion, is very similar to the formation of a spectrum with a wide slit and a succession of shallow prisms. The centre portion remains un- changed for a long time, and the only approach to purity at first is at the two ends, while a considerable series of operations is needed to produce an appreciable change in the centre. The groupsof didymium and yttrium earths are those which have chiefly occupied my attention. On comparing these rare earths we are at once struck with the close mutual similarity, verging almost into identity, of the mem- bers of the same group. The phosphorescent spectra of these earths when their anhydrous sulphates are submitted to the induction discharge in vacuo are extremely complicated, and change in their details in a puzzling manner. For many years I have been persistently groping on in almost hopeless endeavour to get a clue to the meaning I felt con- vinced was locked up in these systems of bands and lines. It was impossible to divest myself of the conviction that I was looking at a series of autograph inscrip- tions from the molecular world, evidently of intense interest, but written in a strange 570 REPORT—1886. and baffling tongue. All attempts to decipher the mysterious signs were, however, for a long time fruitless. I required a Rosetta stone. Down to a date comparatively recent nothing was more firmly fixed in my mind than the notion that yttria was the oxide of a simple body, and that its phosphores- cent spectrum gaye a definite system of coloured bands, such‘as you see in the drawing before you (fig. 2). Broadly speaking, there is a deep red band, a red band, a very luminous citron-coloured band, a pair of greenish-blue bands, and a blue band. It is true these bands varied slightly in relative intensities and in sharpness with almost ‘every sample of yttria I examined; but the general cha- racter of the spectrum remained unchanged, and I had got into the way of looking upon this spectrum as characteristic of yttria: all the bands being visible when the earth was present in quantity, whilst only the strongest band of all—the citron band—was visible when traces, such as millionths, were present. But that the whole system of bands spelled yttria, and nothing but yttria, I was firmly convinced. During the later fractionations of the yttria earths, and the continued observa— tions of their spectra, certain suspicions which had troubled me for some time dolinia) ; tutubiubok Ly fq. 4 VitrinGl Sumariad9. assumed consistent form. The bands which hitherto I had thought belonged to yttria began to vary in intensity among themselves, and continued fractionation increased the differences first observed. Whilst I was in this state of doubt and uncertainty, and only beginning to see my way towards arranging into a consis-: tent whole the facts daily coming to light, help came from an unexpected quarter. M. de Marignac, with whom I had been for some time in correspondence, kindly sent me a small specimen of the earth which he had discovered and provisionally named Ya (now Gadolinia). In the radiant-matter tube this earth gave a bright spectrum, like the one in the diagram before you (fig. 3). The spectrum above it (fig. 2) is that ascribed to yttria. Look at the two. Omitting minor details, Ya is yttria with the chief characteristic band—the citron band—left out, and with the double green band of samaria added to it. Now look at fig. 4, which represents the spectrum of a mixture of sixty-one parts of yttria and thirty-nine parts of samaria. It is identical almost to its minutest detail with the spectrum of Ya, ' TRANSACTIONS OF SECTION B. 571 with this not unimportant difference—the citron band is as prominent as any other line. Ya consists, therefore, of samaria with the greenish blue of yttria and some of the other yttria bands added to it. I may aptly call the Ya spectrum my Rosetta stone. It threw a flood of light on all the obscurities and contradictions I had found so plentiful, and showed me that a much wider law than the one I had been working upon was the true law governing the occurrence of these obscure phenomena. For what does the spectrum of Ya show? It proves that what I had hitherto thought was one of the chief bands in the yttria spectrum—the citron band—could be entirely removed, whilst another characteristic group—the double green of yttria—could also be separated from the citron. It would exceed legitimate limits were I to enter into details respecting the chemical and physical reasons which led me to these definite conclusions. To settle one single point more than 2,000 fractionations have been performed. The meaning of the strongly marked symbolic lines had first to be ascertained. For a long time I had to be content with roughly translating one group of coloured symbols as ‘ yttrium’ and another group as ‘samarium,’ disregarding the fainter lines, shadows, and wings frequently common to both. Constant practice in the decipherment has now given me fuller insight into what I may call the grammar of these hieroglyphic inscriptions. Every line and shadow of a line, each faint wing attached to a strong band, and every variation in intensity of the shadows and wings among themselves, now has a definite meaning which can be translated into the common symbolism of chemistry. In a mineral containing the rarer earths those most widely separated in chemi- cal properties are most easily obtained in a state of comparative purity by simple chemical means. For instance, in separating didymium from lanthanum, or sama- rium from yttrium, a few simple chemical reactions and a little waste will give these bodies in a state of purity ; but when it comes to splitting up yttrium into its components ordinary chemical separation is useless, and fractionation must be pushed to the utmost limit, many thousand operations and enormous waste of material being necessary to effect even a partial separation. Returning, therefore, after this explanatory digression, to the idea of heavy and light atoms, we see how well this hypothesis accords with the new facts here brought to light. From every chemical point of view the stable molecular group, yttrium, behaves as an element. Excessive and systematic fractionation has acted the part of a chemical ‘sorting Demon, distributing the atoms ofyttrium into several groups, with certainly different phosphorescent spectra, and presumably different atomic weights, though all these groups behave alike from the usual chemical point of view. Here, then, is one of the elements the spectrum of which does not emanate equally from all its atoms, but some atoms furnish some, other atoms others, of the lines and bands of the compound spectrum of the element. And as this is the case with one element, it is probably so in a greater or less degree with all. Hence the atoms of this element differ probably in weight, certainly in the internal motions they undergo. Another important inference which may be drawn from the facts is that the atoms of which yttrium consists, though differing, do not differ continuously, but per saltum. We have evidence of this in the fact that the spectroscopic bands characteristic of each group are distinct from those of the other groups, and do not pass gradually into them. We must accordingly expect, in the present state of science, that this is probably the case with the other elements. And the atoms of a chemical element being known to differ in one respect may differ in other respects, and presumably do somewhat differ in mass. Restricted by limited time and means, even a partial separation of these atomic groupings is possible to me only with enormous difficulty. Have we any evidence that Nature has effected such a separation? The following facts I think supply this evidence. The earth yttria occurs in several minerals, all extremely rare. These minerals, are of very diverse chemical composition, and occur in localities widely separated. geographically, Does the pure yttria (pure in respect to every other knowm Lappe} REPORT—1886. element) from these different sources behave differently to the radiant-matter test ? To the chemist hitherto the earth yttria has been the same thing and has possessed the same properties, whatever its source; but armed with this new power of seeing into the atomic groupings which go to make up yttrium, we find evidence of differentiation between one yttrium and another. Thus when the samarskite yttrium was formed all the constituent atoms—deep red, red, orange, citron, greenish-blue, and blue 1—condensed together in fair pro- yaar: the deep red being faintest. In gadolinite yttrium the citron and greenish- lue constituents are plentiful, the red is very deficient, the orange is absent, and the others occur in moderate quantities. In the yttrium from xenotime the citron is most plentiful, the greenish-blue occurs in smaller proportion, the red is all but absent, and the orange is quite absent. Yttrium from monazite contains the greenish-blue and citron, with a fair proportion of the other constituents; the greenish-blue is plentiful, and the red is good. Yttrium from fluocerite is very similar to that from monazite, but the blue is weaker. Yttrium from hielmite is very rich in citron, has a fair quantity of blue and greenish-blue, less of red, no orange, and only a very faint trace of deep red. Yttria from euxenite is almost identical with that from hielmite. Yttria from cerite contains most red and citron, a fair amount of orange, less greenish-blue and blue, and only a trace of deep red. This is unlikely to be an isolated case. The principle is very probably of general application to all the elements. In some, possibly in all elements, the whole spectrum does not emanate from all its atoms, but different spectral rays may come from different atoms, and in the spectrum as we see it all these partial spectra are present together. This being interpreted means that there are definite differences in the internal motions which go on in the several groups of which the atoms of a chemical element consist. For example, we must now be prepared for some such events as that the seven series of bands in the absorption-spectrum of iodine may prove not all to emanate from every molecule, but that some of these molecules emit some of these series, others others, and in the jumble of all these kinds of molecules, to which is given the name ‘iodine vapour,’ the whole Seven series are contributors. To me it appears the theory I have here ventured to formulate, taken in con- junction with the diagram in fig. 1, may aid the scientific imagination to proceed a step or two further in the order of elemental evolution. In the undulating curve may be seen the action of two forces, one acting in the direction of the vertical line, and the other pulsating backwards and forwards like a pendulum, Assume the vertical line to represent temperature slowly sinking through an unknown number of degrees, from the dissociation-point of the first-formed element down to the dissociation-point of those last shown on the scale. But what form of energy is represented by the oscillating line? Swinging to and fro like a mighty pendulum to points equidistant from a neutral centre ; the divergence from neutrality conferring atomicity of one, two, three, and four degrees as the distance from the centre is one, two, three, or four divisions; and the approach to, or retreat from, the neutral line deciding the electro-negative or electro-positive character of the element—all on the retreating half of the swing being positive and all on the approaching half negative—this oscillating force must be intimately connected with the imponderable matter, essence, or source of energy we call electricity. Let us examine this a little more closely. Let us start at the moment when the first element came into existence. Before this time matter, as we know it, was not. It is equally impossible to conceive of matter without energy, as of energy without matter; from one point of view the two are convertible terms. Before the birth of atoms all those forms of energy which become evident when matter acts upon matter could not have existed—they were locked up in the protyle as latent potentialities only. Coincident with the creation of atoms all those attributes and properties which form the means of discriminating one chemical element from another start into existence fully endowed with energy. } For brevity I call them by their dominant spectrum band. TRANSACTIONS OF SECTION B. 573 The pendulum begins its swing from the electro-positive side; lithium, next to hydrogen in simplicity of atomic weight, is now formed; then glucinum, boron, and carbon. Definite quantities of electricity are bestowed on each element at the moment of birth, on these quantities its atomicity depends,! and the types of monatomic, diatomic, triatomic, and tetratomic elements are fixed. The electro- negative part of the swing now commences; nitrogen appears, and notice how curiously position governs the mean dominant atomicity. Nitrogen occupies the position below boron, a triatomic element, therefore nitrogen is triatomic. But nitrogen also follows carbon, a tetratomic body, and occupies the fifth position counting from the place of origin. How beautifully these opposing tendencies are harmonised by the endowment of nitrogen with at least a double atomicity, and making its atom capable of acting as tri- and pentatomic. With oxygen (di- and hexatomic) and fluorine (mon- and heptatomic) the same law holds, and one- half oscillation of the pendulum is completed. Again passing the neutral line the electro-positive elements sodium (monatomic), magnesium (diatomic), aluminium (triatomic), and silicon (tetratomic) are successively formed, and the first com- plete oscillation of the pendulum is finished by the birth of the electro-negative elements, phosphorus, sulphur, and chlorine; these three—like the corresponding elements formed on the opposite homeward swing—having each at least a double atomicity depending on position. . Let us pause at the end of the first complete vibration and examine the result. We have already formed the elements of water, ammonia, carbonic acid, the atmo- sphere, plant and animal life, phosphorus for the brain, salt for the sea, clay for the solid earth, two alkalies, an alkaline earth, an earth, together with their carbonates, borates, nitrates, fluorides, chlorides, sulphates, phosphates, and silicates, sufficient for a world and inhabitants not so very different from what we enjoy at the present day. ‘True, the human inhabitants would have to live in a state of more than Arcadian simplicity, and the absence of calcic phosphate would be awkward as far as bone is concerned. But what a happy world it would be! No silver or gold coinage, no iron for machinery, no platinum for chemists, no copper wire for telegraphy, no zinc for batteries, no mercury for pumps, and, alas! no rare earths to be separated. The pendulum does not, however, stop at the end of the first complete vibration ; it crosses the neutral point, and now the forces at work are in the same position as they were at the beginning. Had everything been as it was at first, the next element again would have been lithium, and the original cycle would have recurred, repeating for ever the same elements. But the conditions are not quite the same ; the form of energy represented by the vertical line has declined a little—the temperature has sunk—and not lithium, but the one next allied to it in the series comes into existence—potassium, which may be regarded as the lineal descendant of lithium, with the same hereditary tendencies, but with less molecular mobility and higher atomic weight. Pass we rapidly along the to and fro curve, and in nearly every case the same law is seen to hold good. The last element of the first complete vibration is chlorine. In the corresponding place in the second vibration we do not have an exact repetition of chlorine, but the very similar body bromine; and when for a third time the position recurs we see iodine. I need not multiply examples. In this far-reaching evolutionary scheme it could not come to pass that the 1 ‘Nature presents us with a single definite quantity of electricity. . . . For each chemical bond which is ruptured within an electrolytea certain quantity of electricity traverses the electrolyte, which is the same in all cases..—G. Johnstone Stoney, ‘On the Physical Units of Nature.’ British Association Meeting, 1874, Section A. ° Phil. Mag., May 1881. ‘The same definite quantity of either positive or negative electricity moves always with each univalent ion, or with every unit of affinity of a multivalent ion.— Helmholtz, Faraday Lecture, 1881. ‘ Every monad atom has associated with it a certain definite quantity of electricity ; every dyad has twice this quantity associated with it ; every triad three times as much, and so on.'—O. Lodge, ‘Or Electrolysis,’ British Association Report, 1885. 574 REPORT— 1886. potential elements would all be equal to one another. Some would be unable to resist the slightest disturbance of the unstable equilibrium in which they took their rise; others would endure longer, but would ultimately break down as temperature and pressure varied. Many degrees of stability would be here repre- sented ; not all the chemical elements are equally stable, and if we look with scrutinising eyes we shall still see our old friend the missing link, coarse enough to be detected by ordinary chemical processes, associated in the groups containing such elements as iron, nickel, and cobalt; palladium, ruthenium, and rhodium ; iridium, osmium, and platinum. Whilst in their more subtile form these missing links present themselves as the representatives of the differences which I have detected and described between the atoms of the same chemical element. Dr. Carnelley has pointed out that ‘ those elements belonging to the even series of Mendeleeff’s classification are always paramagnetic, whereas the elements belong- ing to the odd series are always diamagnetic.’ On this curve the even series to the left, as far as can be ascertained, are paramagnetic, and, with a few exceptions, all to the right are diamagnetic. The very powerful magnetic metals, iron, nickel, cobalt, and manganese, occur close together on the proper side. The interperiodic groups of which palladium and platinum are examples are said to be feebly mag- netic, and if so they form the exceptions. Oxygen, which, weight for weight, is more magnetic than iron, comes near the beginning of the curve, while the power- fully diamagnetic metals, bismuth and thallium, are at the opposite end of the curve. On the odd, or diamagnetic half of the swing, the energy appears to have con- siderable regularity, whilst it is very irregular on the opposite side of the curve. Thus, between the extreme odd elements, silicon (28), germanium (73), tin (118), the missing element (168), and lead (208), there is a difference of exactly 45 units, conferring remarkable symmetry on one half of the curve. The differences on the even side are 36, 42, 51, 39, and 53 (giving the missing element between cerium and thorium an atomic weight of 180); these at first sight appear conformable to no law, but they become of great interest when it is seen that the mean difference of these figures is almost exactly the same as that on the other side of the curve —viz. 44°2. This uniformity of difference—actual on the one side and average on the other —brings out the important inference that, whilst on the odd side there has been little or no variation in the vertical force, minor irregularities have been the rule on the even side. That is to say, the fall of temperature has been very uniform on the odd side—where every element formed during this half of the vibration is the representative of a strongly marked group—sodium, magnesium, aluminium, silicium, phosphorus, sulphur, and chlorine ; whilst on the even side of the swing the temperature has sunk with considerable fluctuations, which have prevented the formation here of any well-marked groups of elements, with the exception of those of which lithium and glucinum are the types. If we can thus trace irregularities in the fall of temperature can we also detect: any variation in the force represented by the pendulous movement? I have assumed that this represents chemical energy. In the early formed elements we have those in which chemical energy is at its maximum intensity, while, as we descend, affinities for oxygen are getting less and the chemism is becoming more and more sluggish. Part may be due to the lower temperature of generation not permitting such molecular mobility in the elements, but there can be little doubt that the chemism-forming energy, like the fires of the cosmical furnace, is itself dying out. I have endeavoured to represent this gradual fading out by a diminution of amplitude, the curve being traced from a photographic record of the diminution of the are of vibration of a body swinging in a resisting medium. When we look on a curve of this kind there is a tendency to ask, what is there above and below the portion which is seen? At the lower end of our curve what is there to be noted? We see a great hiatus between barium (137) and iridium (192'5), which it seems likely will be filled up by the so-called rare elements. Judging from my own researches, it is probable that many of these earthy elements will be found included in one or more interperiodic groups, whilst the higher mem- TRANSACTIONS OF SECTION B. 575 bers of the calcium, the potassium, the chlorine, and the sulphur groups, together with the elements between silver and gold, cadmium and mercury, indium and thallium, and antimony and bismuth, are still waiting to be discovered. We now come to an oasis in the desert of blanks. Platinum, gold, mercury, thallium, lead, and bismuth, all familiar friends, form a close little group by themselves, and then after another desert space the list is closed with thorium (233) and uranium 240). : This oasis and the blanks which precede and follow it may be referred with much probability to the particular way in which our Earth developed into a mem- ber of our solar system. If this be so it may be that on our Earth only these blanks occur, and not generally throughout the universe. What comes after uranium? I should consider that there is little prospect of the existence of an element much lower than this. Look at the vertical line of temperature slowly sinking from the upper to the lower part of the curye; the figures representing the scale of atomic weights may be also supposed to represent, inversely, the scale of a gigantic pyrometer dipping into the cauldron where suns and worlds are in process of formation. Our thermometer shows us that the heat has been sinking gradually, and, part passu, the elements formed have increased in density and atomic weight. This cannot go on for an indefinite extent. Below the uranium point the temperature may be so reduced that some of the earlier formed elements which have the strongest affinities are able to enter into combination among themselves, and the result of the next fall in temperature will then be—instead of elements lower in the scale than uranium—the combination of oxygen with hydrogen, and the formation of those known compounds the dissocia- tion of which is not beyond the powers of our terrestrial sources of heat. Let us now turn to the upper portion of the scheme. With hydrogen of atomic weight = 1, there is little room for other elements, save perhaps for hypothetical helium, But what if we get ‘through the looking-glass, and cross the zero-line in search of new principles—what shall we find the other side of zero? Dr. Car- nelley asks for an element of negative atomic weight ; here is ample room and verge enough for a shadow series of such unsubstantialities. Helmholtz says that elec- tricity is probably as atomic as matter ;1 is electricity one of the negative elements ? and the luminiferous ether another? Matter, as we now know it, does not here exist ; the forms of energy which are apparent in the motions of matter are as yet only latent possibilities. A substance of negative weight is not inconceivable.? But can we form a clear conception of a body which combines with other bodies in proportions expressible by negative quantities ? A genesis of the elements such as is here sketched out would not be confined to our little solar system, but would probably follow the same general sequence of events in every centre of energy now visible as a star. Before the birth of atoms to gravitate towards one another, no pressuré could be exercised ; but at the outskirts of the fire-mist sphere, within which all is protyle— at the shell on which the tremendous forces involved in the birth of a chemical element exert full sway—the fierce heat would be accompanied by gravitation sufficient to keep the newly-born elements from flying off into space. As tempera- ture increases expansion and molecular motion increase, molecules tend to fly asunder, and their chemical affinities become deadened ; but the enormous pressure of the gravitation of the mass of atomic matter outside what I may for brevity call the birth-shell would counteract this action of heat. Beyond this birth-shell would be a space in which no chemical action could take place, owing to the temperature there being above what is called the dissocia- tion-point for compounds. In this space the lion and the lamb would lie down 1 “Tf we accept the hypothesis that the elementary substances are composed of atoms, we cannot avoid concluding that electricity also, positive as well as negative, is divided into definite elementary portions, which behave like atoms of electri- city. —Helmholtz, Faraday Lecture, 1881. ? “T can easily conceive that there are plenty of bodies about us not subject to this intermutual action, and therefore not subject to the law of gravitation.’—Sir George Airy. Faraday’s Life and Letters, vol. ii. p. 354. 576 REPORT— 1886. together; phosphorus and oxygen would mix without union; hydrogen and chlorine would show no tendency to closer bonds; and even fluorine, that energetic gas which chemists have only isolated within the last month or two, would float about free and uncombined. Outside this space of free atomic matter would be another shell, in which the formed chemical elements would have cooled down to the combination-point, and the sequence of events so graphically described by Mr. Mattieu Williams in ‘ The Fuel of the Sun ’ would now take place, culminating in the solid earth and the commencement of geological time. And now I must draw to a close, having exhausted not indeed my subject, but the time I may reasonably occupy. We have glanced at the difficulty of defining an element; we have noticed, too, the revolt of many leading physicists and chemists against the ordinary acceptation of the term element. We haye weighed the im- probability of their eternal self-existence or their origination by chance. As a re- maining alternative we have suggested their origin by a process of evolution like that of the heavenly bodies according to Laplace, and the plants and animals of our globe according to Lamarck, Darwin, and Wallace. In the general array of the elements, as known to us, we have seen a striking approximation to that of the organic world. In lack of direct evidence of the decomposition of any element, we have sought and found indirect evidence. We have taken into consideration the light thrown on this subject by Prout’s law, and by the researches of Mr. Lockyer in solar spectroscopy. We have reviewed the very important evidence drawn from the distribution and collocation of the elements in the crust of our earth. We have studied Dr. Carnelley’s weighty argument in favour of the com- pound nature of the so-called elements from their analogy to the compound radicles. We have next glanced at the view of the genesis of the elements; and, lastly, we have reviewed a scheme of their origin suggested by Professor Reynolds’s method of illustrating the periodic classification. Summing up all the above considerations we cannot, indeed, venture to assert positively that our so-called elements have been evolved from one primordial matter ; but we may contend that the balance of evidence, I think, fairly weighs in favour of this speculation. This, then, is the intricate question which I have striven to unfold before you, a question which I especially commend to the young generation of chemists, not only as the most interesting but the most profoundly important in the entire compass of our science. I say deliberately and advisedly the most interesting. The doctrine of evolu- tion, as you well know, has thrown a new light upon and given a new impetus to every department of biology, leading us, may we not hope, to anticipate a corresponding wakening light in the domain of chemistry ? I would ask investigators not necessarily either to accept or to reject the hypo- thesis of chemical evolution, but to treat it as a provisional hypothesis; to keep it in view in their researches, to inquire how far it lends itself to the interpretation of the phenomena observed. and to test experimentally every line of thought which points in this direction, Of the difficulties of this investigation none can be more fully aware‘than myself. I sincerely hope that this, my imperfect attempt, may lead some minds to enter upon the study of this fundamental chemical question, and to examine closely and in detail what I, as if amidst the clouds and mists of a far distance, have striven to point out. The following Papers were read :-— 1. On the Absorption Spectra of Uranium Salts. By W. J. Russert, F.R.S., and W. Larrark, F.C.S. Well-marked absorption bands are produced in the visible spectrum by the differ- ent salts of this metal. The salts are divided into two very distinct classes, uranous and uranic salts, and each class gives an entirely different absorption spectrum ; TRANSACTIONS OF SECTION B. 577 both consist of three distinct bands or groups of bands: those produced by the uranous salts are at the red end of the spectrum, and those produced by the uranic salts at the blue end, the one set of bands beginning where the other set ends, so that when both salts are together in solution there are a series of bands visible which are distributed with tolerable regularity over the whole visiblespectrum. Nine uranic salts, some organic some inorganic, have been examined, and it has been found that all give the same spectrum, that is, the spectrum is unaffected by the acid radicle. With other metals, such as cobalt for instance, this is not the case, different radicles producing different spectra. This spectrum, common apparently to all uranic salts, 1s however slightly altered by the addition of free acid, the acid causing a diminu- tion of intensity in the least refrangible hands, and causing an apparent slight shift in others. Crystals of the uranic nitrate give an absorption spectrum similar to that produced by an aqueous solution of this salt. The uranous salts give also in all cases examined a common spectrum, and one in which all the bands are less refrangible than those belonging to the uranic salts. The authors have also examined a few of the uranous salts in the solid state, and find that these salts have then a far more complicated spectrum than when in solution. 2. The Air of Dwellings and Schools, and its relation to Disease. By Professor T. Caryeniey, D.Sc. 3. On some probable new Elements. By ALEXANDER PRINGLE. 4. On the Action of Bromine on the Trichloride of Phosphorus.! By A. L. Stern. After a short historical introduction experiments were described in which phos- phorus trichloride and bromine were mixed in various proportions; in all cases a considerable quantity of heat was evolved, and when sufficient bromine was present crystals were dey osited on cooling; on analysing these it was found that the amount of bromine present at any given temperature was proportional to the amount of bromine present in the mixtures, also that those crystals which contained the most bromine were the least stable; at a temperature of 10°C. it was possible to obtain a compound containing ten atoms of halogen, while at 35°C. the compound PCl,Br, was decomposed (Michaelis). It was also found that bromine replaces part of the chlorine of the trichloride, but not much more than half even when such a large excess was present as twelve atoms of bromine to one of the trichloride ; Gladstone, however, found that in the presence of a small quantity of iodine all the chlorine of the trichloride may be replaced by bromine and the penta-bromide formed. The constitution of these compounds was then discussed and it was suggested that they are merely compounds of phosphorus with varying proportions of halo- gen, and not molecular compounds; the number of atoms of halogen with which one atom of phosphorus can combine being an inverse function of the temperature. 5. Dissociation and Contact-action.2 By the Rey. A. Irvine, B.Sc., B.A. The author refers to a letter of his which appeared in ‘ Nature’ on March 25 last, in which he suggested that the true explanation of the many instances known of contact-action of solid bodies in facilitating combination of gases, which under ordinary conditions and in the free state are chemically inert to one another, was to be found in the transformation of a portion of the energy of translation of the molecules into intramolecular work, producing (or tending to produce) dissociation as a preliminary to chemical change. Printed in full in Journ. Chem. Soc., 815, 1886. * Published in extenso, Chemical Nen:s, October 8, 1886. , , 1886. PP 578 REPORT—1886. In this paper such explanations as have been offered from time to time are criticised and rejected as inapplicable to ail the phenomena, and an attempt is made to reason out a general explanation on purely thermo-dynamical principles. The initial-temperature of dissociation is referred to the inequality of the atom-tempera- tures (absolute) of the molecules, there being (from a variety of causes) a number of molecules in every mass of gas in a state of greater thermal activity (both as regards translational and internal vibrational energy) than that which corresponds to the mean condition which is indicated by the thermometer. For such molecules a smaller addition of heat is required to bring about dissociation, while the enor- mous increase in the extent of solid surface presented by the introduction of a porous: or finely divided solid, increases proportionately the number of instances of impact in a given period of time, and a corresponding increase in the amount of intra- molecular work done in promoting the vibrational energy of the atoms. The term ‘quasi-nascent state’ is used to indicate such a degree of tension, thus brought about within some of the molecules, that atoms of opposite electro-chemical energies can, under the influence of their mutual attraction, escape from the mole- cules in which they were previously held, and enter into new combinations. Collateral evidence of the truth of the theoretical view here propounded is brought forward, (1) from a purely dynamical example given by Sir W. Thomson in a discussion in Section A last year; (2) from the action of Mr. Crookes’ radio- meter; (3) from a lecture on dissociation given by Mr. Frederick Siemens in May last at the Royal Institution. The general application of the theory is pointed out as claiming more considera- tion than the more empirical explanations hitherto offered, each of which only applies to a few instances of the kind. It also enables us to refer the contact influ- ence of chemically inert solid bodies, and the action of such purely physical agencies as heat, electricity, and light, in promoting combination, to the same general principles, while it seems to extend our idea of the action of atoms in the nascent state. FRIDAY, SEPTEMBER 3. The following Reports and Papers were read :— 1. Second Report of the Committee on Vapour Pressures and Refractive Indices of Salt Solutions—See Reports, p. 204. 2. Second Report of the Committee on certain Physical Constants of rae especially the Expansion of Saline Solutions.—See Reports, p- : 3. On the Phenomena and Theories of Solution. By Professor W. A. Titprn, F.R.S.—See Reports, p. 444. 4, Water of Orystallisation.! By Dr. Nico. The author examines the evidence for and against the existence of water of erystallisation in solution, derivable from thermo-chemical and other data. He shows that there is no relation between heat of hydration of the solid salt and the number of water molecules in the hydrated salt; that itis not sufficient to deduct the heat of change of state of the water to obtain the true heat of solution of a dehydrated salt; and that the heat of neutralisation of a dissolved base by a dissolved acid is conclusive against the existence of water of crystallisation in aqueous solution, for with the seven soluble bases this is a constant for H,SO,, and Since published in the Chemical News, p. 191, 1886. TRANSACTIONS OF SECTION B. 579 another constant for 2HCl and 2HNO,, while the sulphates and other salts formed possess in the solid state most varied amounts of water of crystallisation, and if this exists in solution it would be necessary to assume that the constancy of the neutralisation results is a coincidence, an assumption directly opposed to the probabilities of the case. 5. On the Magnetic Rotation of Mixtures of Water, and some of the Acids of the Fatty Series with Alcohol and with Sulphuric Acid, and Observations on Water of Orystallisation.' By W. H. Perkin, Ph.D., F.R.S. The author first pointed out that the magnetic rotation of water was higher than that of a sum of the value of H,+0O, as deduced from other compounds, and that therefore the magnetic rotation of a body containing these elements would show whether they existed as water or were otherwise combined. Formic, acetic, and propionic acid were then each mixed with water in the proportions of one mole- cule of acid to one of water, and examined as to their molecular rotation. This was of special interest because acids so diluted were believed to form trihydric alcohols, Alcohol diluted in a similar manner was aiso examined at the same time for the sake of comparison, because it could not form a compound with water. The result of the numbers obtained from the magnetic rotation showed that these diluted compounds consist simply of the acids + water, the diluted alcohol giving similar confirmatory numbers. Sulphuric acid was then examined in a similar manner, both concentrated and hydrated by the addition of water in the proportion of one, two, and three mole- cules to one of acid. From the results obtained the author concludes that sulphuric acid forms with water the compound (HO),SO only. The study of these hydrated compounds having caused the author to consider the subject of water of crystallisation, he first draws attention to the want of consistency as to the presence or absence of water of crystallisation in the simple salts of metals belonging to the same class, and to the same thing shown in the existence of hydrated methyl-bromide, &c., and concludes that its relation to a salt or other body has not any connection with chemical combination, but that it is purely physical, and is present as a necessity of the crystalline form, and that it is present only when it is conducive to the production of that form which is most readily produced under the circumstances existing at the time, in support of which he brings forward the case of the alums and other isomorphous compounds, and shows that if this be the function of water of crystallisation salts containing it when dissolved will no longer remain in union with it, which is now believed to be the case by so many who have studied the subject of the solution of salts. 6. On the Nature of Liquids. By WitttamM Ramsay, Ph.D., and Sypnuy Youne, D.Sc. The subject of this paper may well be included in a discussion on the nature of solution, for it is impossible to devise a completely satisfactory theory of solution without a knowledge of the molecular structure of the solvent. During the last few years we have made determinations of the vapour pressures, densities of the saturated and unsaturated vapour, specific gravities, and, in some cases, compressibilities of methyl and ethyl alcohol, ether, and acetic acid under various conditions of pressure and temperature. By means of the thermo-dynamical equation t J the heats of vaporisation have also been calculated. The data which bear most strongly on the subject under discussion are the d, L=(§,-8,) . 1 For full paper see Jour. Chem. Soc., vol. xlix. p. 777. PP2 580 REPORT—1 886. densities of the saturated vapour, that of hydrogen under similar conditions of tem- perature and pressure being taken as unity. At low temperatures the saturated vapours of the alcohols and ether follow Boyle’s and Gay Lussac’s laws; but if the temperature is raised the density of the saturated vapour is found to increase, slowly at first, but more and more rapidly, until the critical point is reached, when the specific gravity of the liquid is equal to that of its saturated vapour, and the devia- tion from Boyle’s law is very great. Thus with ethyl alcohol the density of the saturated vapour is normal at about 40°, and it remains normal at lower tempera- tures. With acetic acid very different results are obtained. The constants for this body have not been determined up to the critical point, the temperature being too high for the method adopted. From about 140° to 280°, however, the density of the saturated vapour is found to increase, and there can be no doubt that this increase would go on up to the critical point. When the temperature is reduced below 140° the density of the saturated vapour (which at this point is about 50, the normal density being 30) does not continue to decrease but becomes nearly constant, and at still lower temperatures rises again more and more rapidly until at 50° it is nearly 60. There is then a marked difference between such substances as ethyl alcohol, in which no dissociation of any kind is known to occur, and acetic acid, the vapour of which is believed by many chemists to consist, in part, of molecules of the formula n(C,H,O,), n being generally supposed equal to 2. It is very improbable that the increase of the density of the saturated vapour with rise of temperature, which appears to be common to all bodies, is due to the union of simple gaseous molecules to form complex groups, for dissociation is always in- creased by rise of temperature; on the other hand, owing to the high pressure, the ‘molecules are brought into close proximity, and the abnormality may be caused by a general attraction of the molecules for each other. At low temperatures, at which the pressure is small, the molecules are far apart, and such a general attrac- tion is out of the question. The deviation in the case of acetic acid at low temperatures is therefore probably due to the combination of the simple gaseous molecules to form complex groups of the formula n(O,H,0,). This is borne out by the fact that with nitric peroxide, the vapour of which is known to dissociate according to the equation N,O,=2NO,, a similar increase of the density of the saturated vapour takes place. The densities of the unsaturated vapour at various constant temperatures have been determined by the Natansons (‘ Wied. Ann,’ July 1886) and the vapour pressures by ourselves (‘ Phil. Trans,’ 1885). The junction of the isothermals showing the relation of pressure to vapour density with the horizontal lines indicating vapour pressures gives points on the curve representing the relation of the densities of the saturated vapour to pressure; and it is thus found that the density of the saturated vapour increases with fall of temperature and pressure. It is extremely improbable that the increase of the density of the saturated vapour of acetic acid at both high and low temperatures can be due to the same cause, the conditions being so totally different ; and it may fairly be concluded that at high temperatures the abnormality of this and of all other bodies is due to a physical rather than a chemical attraction. The existence of complex molecular groups in the vapours of normal substances, such as alcohol, is therefore very un- likely, and it can hardly be supposed that they are formed at the moment of con- densation ; hence, in all probability, the molecules of ordinary liquids are simple gaseous molecules in close proximity. Other facts observed in the course of this research lead to the same conclusion. We shall discuss their bearing on the question in the ‘ Philosophical Magazine.’ We have attempted to study the solubility of eosin in alcohol at temperatures above the critical point, but the experimental difficulties are so great that no very definite conclusions have been arrived at. It appears, however, most probable that at temperatures but slightly higher than the critical point, the eosin remains in solution for some time (as shown by its fluorescence), but that it is gradually deposited. , TRANSACTIONS OF SECTION B. 581 7. On the Nature of Solution! By Professor Spencer U. PICKERING. Although various special experiments seem to render it incontestable that hydrates of a salt do exist in solution in some cases, the strength of the hydrate theory should be derived from more general considerations as to the nature of the solyent and substance dissolved, and from the thermal results of dissolution. At the same time, however, equally general considerations render this theory-inade- quate to explain all the facts observed, though to such special lines of argument, such as those which Dr. Nicol derives from the specific volumes, no weight what- ever can be attached, for they would lead to the conclusion that the radicles com- posing the salt itself are no more united than is the salt with its water. The explanation of this conflicting evidence may be explained by the recognition of the real complexity of the units of matter; a great number of our so-called mole- cules unite to form aggregates which bear the stamp of true chemical compounds in most respects, but are so greatly influenced by physical conditions that their composition, to our imperfect means of investigation, appears indefinite. The existence of such compounds alone can explain the peculiarities of minerals, artificial crystals of isomorphous salts, alloys, basic salts, &c. Dissolution is a result not of the formation of definite hydrates only, but also of (apparently) indefinite hydrates. The formation of these hydrates would always be accompanied by an evolution of heat, but at the same time the aggregates of a solid being more complex than those of a liquid, an act of decomposition absorbing heat would also be a no lessinvariable accompaniment. The coexistence of two such counter- acting actions can alone explain all the thermal effects of dissolution. SATURDAY, SEPTEMBER 4. ' The following Papers were read :— 1. On the Fading of Water-colowrs. By Professor W. N. Hartuey, F.R.S. Referring to the article Light and Water-colours, written by Mr. J. C. Robinson, in the ‘ Nineteenth Century,’ Professor Hartley pointed out that colours consist of mineral substances, for the most part of a stable character and organic substances consisting of stable colours and unstable changeable colours. With the exception of ultramarine, bodies of the former class may be generally considered as unalterable unless they contain lead or mercury; those of the second class may be considered alterable under certain conditions. Theaction of light, according to the researches of Chastaing, on these two classes of substances when it is capable of affecting them is different : on mineral substances the red rays cause oxidation ; the oxidising power decreases as the rays tend more towards the yellow; the yellowish- green rays are without action and form a neutral region ; the blue rays reverse the action of the red—for they promote reduction—and this action increases in intensity in the violet and ultra-violet rays, On organic substances the action of light is an oxidising one throughout, con- tinuously increasing in power as the rays’extend through the red and yellow into the violet end of thespectrum. There is, however, a modification in the green, the rays having a diminished oxidising power. The action of light on organic sub- stances is not confined to oxidation, for bodies of a complex and unstable character may be changed in composition, and, being resolved into more stable compounds, changed in colour or rendered colourless. Experiment on colours showed that this was apparently the case with crimson lake, gamboge, bistre, and to a less extent with brown madder and sepia. Indigo is permament. Ultramarine is bleached by acids, but not by light. In order to preserve water-colour drawings in which yellow and delicate red tints 1 Chemical News, 54, p. 215. 582 REPORT—1886. are largely used, as, for instance, Turner's sun-light pictures, they should be kept in a very subdued light, preferably of a yellow tint, such as is obtained by blinds of un- bleached linen. For artificial illumination the arc-light is unsuitable, but incan- descence lamps are preferable to gas, as yielding no products of combustion, which in the case of gas are capable of causing injury. The action of the violet rays is two to three times as powerful as the red or yellow; and there is a great difference between the action of diffused daylight sufficiently strong to view pictures, and direct sunlight. Without exact measurements it is difficult to appreciate its magnitude, but the latter may be safely set down as on an average forty times, and in summer even probably four hundred times as great as the former ; hence a picture which would fade in ten years in sun-light might be preserved for several hundred years in a subdued yellow light. The author has not observed any destructive action of light on grey tints made from mixtures of indigo and light red, even in sketches painted as long as sixty years ago, by his father, and since exposed to subdued daylight. The acidity in drawing paper should be corrected by a wash of a dilute solution of borax, and in no case ought any paste or glue to be placed at the back of a drawing for the purpose of mounting it. 2. On the Distribution of the Nitrifying Organism in the Soil. By R. Warineton, F.B.S. Previous experiments, conducted at Rothamsted on this subject (‘ Trans, Chem. Soc.’ 1884, p. 645) had led to the conclusion that the nitrifying organism is always to be met with down to 9 inches from the surface, and that at 18 inches it is sometimes present ; but experiments with soil 2 to 8 feet from the surface failed to yield evidence of the presence of the organism. Further experiments have been made in 1885, and during the present year, both in the field with the stiff clay subsoil previously worked on, and in another field having a loamy subsoil ; in all sixty-nine new experiments have been made. ‘The soil in the previous experiments was removed, with suitable precautions, from a freshly cut surface, and placed in sterilised solutions consisting of diluted urine (0-4 per cent.) It having since been found that the facility with which urine nitrifies is greatly increased by the presence of gypsum (‘Trans. Chem. Soc.’ 1885, p. 758), an addition of a small quantity of gypsum was made to the solutions employed in all the recent experiments; rather larger quantities of soil were also employed. The results may be summarised as follows :— Number of Number of Solutions | Number Nitrifying Depth of Soil Experiments Nitrifying out of 10 Trials & Less than 2 feet ip NV% 10:0 2 feet 11 11 10:0 3S 11 10 oy As 11 7 6-4 50s 2 1 5:0 esr 9 4 an Te By 2 0 0:0 Body 6 0 0-0 Six of the above experiments were made with chalk, which underlies the Rothamsted subsoil; the chalk was from depths of 5, 6, 7, and 8 feet. None of the samples of chalk produced nitrification. The new results show a far deeper distribution of the nitrifying organism than was concluded from the earlier experiments. The power of producing nitrification is now found to exist generally down to 3 feet from the surface. Below this point the occurrence of the organism becomes less frequent, though at 5 and 6 feet about half the trials resulted in nitrification. With soil from 7 and 8 feet TRANSACTIONS OF SECTION B. 583 no nitrification was obtained. The considerable difference between the earlier and later results is to be attributed to the employment of gypsum in the later solutions. The nitrifying organism in the subsoil is deed less abundant, and probably much more feeble than in the surface soil, and is apparently unable to start nitrification in the decidedly alkaline solution which urine produces in the absence of gypsum. Although it appears that the nitrifying organism may exist at considerable depths, nitrification is practically confined to the surface soil. The quantity of nitrogen as nitric acid annually obtained in the drainage water from soils of different depths in the drain gauges at Rothamsted is on an average of nine years :— Soil 20 inches deep. : : . 40.2 lbs. per acre Soil 40s, > : 2 : wat 3b70 $s Soil 60a, ee 5 ! : PLESS CMs, 2 Ps; There is no evidence here of a greater production of nitrates when the subsoil is included in the experiment. Nitrates are always found most abundantly in the surface soil unless heavy rain has occurred to wash them downwards. Two fallow soils at Rothamsted were found to contain the following quantities of nitrogen as nitrates in lbs. per acre :— ist 9inches . ‘ F F s ioc 28:5 40-1 2nd » 5:2 14:3 3rd ef = 5 —~ 55 Total. Boek 59°9 3. On the Action of Drinking-water on Lead. By Dr. C, Mrrmorr Trvx. 4. Micro-Organisms in Drinking-water. By Professor Opune, F.B.S. MONDAY, SEPTEMBER 6. The following Report and Papers were read :— 1. Report of the Committee appointed to investigate the Influence of the Silent Discharge of Electricity on Oxygen and other Gases.—See Reports, p. 213. 2. On the Preservation of Gases over Mercury.’ By Haron B. Drxoy, V.A., FB.S. The author has found that different gases (hydrogen, electrolytic gas, cyanogen, and sulphurous acid) could be preserved over dry mercury for several years with- out any sensible alteration. This result is contrary to the conclusion arrived at by Faraday, that it was impossible to preserve gases over dry mercury, but agrees with the experiments of Sir Humphry Davy, recorded in the Laboratory Notebook of the Royal Institution. The author collected the gases in hot tubes over pure hot mercury. 3. On the Methods of Chemical Fractionation.” By Witu1am Croorss, F.R.S., V.P.C.S. Broadly speaking, the operation of chemical fractionation consists in fixing 1 Printed in extenso in the Chem. News, 54, p. 227. 2 The original paper was published in extenso in the Chemical News for September 410, 1886. 584 REPORT—1 886. upon some chemical reaction in which there is the most likelihood of a difference in the behaviour of the elements under treatment, and performing it in an incom- plete manner, so that only a certain fraction of the total bases present is separated, the object being to get part of the material in the insoluble, and the rest in the soluble, state. The operation must take place slowly, so as to allow the affinities —which, by the nature of the case, are almost equally balanced—time to have free play. Let us suppose that two earths are present, almost identical in chemical properties, but dittering by an almost imperceptible variation in basicity. Add to the very dilute solution dilute ammonia in such amount that it can only precipi- tate half the bases present. The dilution must be such that a considerable time elapses before the liquid begins to show turbidity, and several hours will haye to elapse before the full effect of the ammonia is complete. On filtering we have the earths divided into two parts, and we can easily imagine that now there is a slight difference in the basic value of the two portions of earth; that in solution being, by an almost imperceptible amount, more basic than that which the ammonia has precipitated, This minute difference is made to accumulate by a systematic process until it becomes perceptible by a chemical or physical test. In most methods of fractionation a rough sort of balance of affinities is arrived at before long, beyond which further separation by the same method is difficult. I have long noticed this action when fractionating with ammonia, with oxalic acid and nitric and with formic acid. One valuable point which renders this fact noteworthy is that the balance of affinities revealed by fractionation is not the same with each method. It was in consequence of the experience gained in these different methods of fractionation that in my paper read before the Royal Society, June 10 last (‘Chemical News,’ vol. liv. p. 13), after stating that I had not been able to separate didymium into Dr. Auer’s two earths, I said,‘ Probably didymium ’ will be found to split up in more than one direction according to the method adopted.’ The process adopted must vary according to the bodies under treatment. Frac- tional crystallisation has yielded new results with didymium in the hands of Dr. Auer von Welsbach; and precipitation with formic acid, with ammonia, with ammonium oxalate, crystallisation of the oxalates from strong nitric acid, and fusing the nitrates and chlorides have all given me good results. Working with the samarskite earths, fractional precipitation with oxalic acid separates first erbia, holmia, and thulia, then terbia, and lastly yttria. This is the only method which is applicable for the separation of small quantities of terbia from yttria. Fusing the nitrates separates ytterbia, erbia, holmia, and thulia from yttria. It is not so applicable when terbia is present, and is most useful in purifying the gadolinite earths. This process is the only one known for separating ytterbia from yttria. The formic acid process is best for separating terbia, as terbic formate is diffi- cultly soluble in water, the other formates being easily soluble. Selection must be made of these methods according to the mixture of earths under treatment, changing the method as one earth or the other becomes concen- trated on one side or thrown out on the other. Each operation must be repeated very many times before even approximate purity is attained. The operations are more analogous to the separation of members of homologous series of hydrocarbons by fractional distillation than to the separations in mineral chemistry as ordinarily adopted in the laboratory. ‘When the balance of affinities, of which I spoke above, seems to be established, the earths appear in the same proportion in the precipitate and the solution; they are thrown down by ammonia, and the precipitated earths are worked up by some other process so as to alter the ratio between them, when the previous operation can be again employed. Fractional precipitation by ammonia is the process generally adopted, for ea in some cases it is not so powerful as other processes it is more generally applicable. The best plan is to add half the equivalent amount of precipitant to the liquid, TRANSACTIONS OF SECTION B. 585 and, after complete settlement, filter. Starting with, say, 1000 grms. in the zero bottle, transfer the filtrate to bottle —1 and the precipitate to bottle +1. Then add another 1000 grms, to the 0 bottle, and repeat the operations as in the following table :— NuMBERS OF THE Borrres. -6 -5 -4 -3 -2 -l 0 at 2 3 4 5 6 1000 500 1000 500 250 500 500 500 2650 125 250 3875 600 375 250 125 638 125 250 875 375 375 260 125 63 81 63 156 250 312 3875 312 250 156 635 31 15 31 94 156 234 312 312 312 284 156 94 31 165 AES Ot After the sixth fractionation the 2000 grms. of earth are spread out amongst. 13 bottles in the proportions represented in the bottom line. : The separation of two earths by this plan is comparatively easy. The pre- cipitation by ammonia depends not directly on the affinities of the earths for the acid, but rather on the excess of affinity of the precipitating ammonia. For if the affinities of the two earths are represented by 100 and 101, and that of ammonia by 150, the affinities on which the precipitation depends would be represented by 150—100=50, and 150—101 =49, the difference of which is 2 per cent. of the larger. Now if a precipitant of which the affinity for the acid was only 110 were used, the affinities in question would be 110—100=10, and 110—101=9, and the difference, 10—9=1, is 10 per cent. of the larger instead of only 2 per cent. Therefore if an alkali of which the affinity of the acid was only a little greater than that of earths were used for precipitation, it is likely that the differences between the two earths would come out more strongly, and the labour of fractional precipitation might be much reduced. Professor Stokes has suggested that some of the compound ammonias might prove useful as precipitants instead of ammonia. — I have not, however, tested the suggestion. The amount of earths present has to be determined before each precipitation, so as to now how much ammonia is to be added to get half precipitated. This is. done by standard solutions, and when everything is in good order it does not occupy much time. Filtration is always the lion’s share of the trouble. The above calculations have been based on the assumption that only two earths are present, If more than two are present, the process fails in any reasonable time to yield practically pure specimens of more than two out of a group of closely allied earths. Thus, if there are as many as three earths, say A, B, and C, whose positions in reference to the chemical process employed are in the order of sequence in which they are written, we may get a specimen of A as nearly as we please free from B and C, and a specimen of C as nearly as we please free from A and B, but we cannot get a specimen of B practically free from A and C, The law seems to be that to obtain practically pure specimens of three closely alliel earths, tt is essential to have recourse to at least two different chemical processes. The mere continued repetition of the same process will not do, unless indeed the operations are repeated such a vast number of times as to make the approximate expressions no longer applicable, even though the substances are chemically very close. With a greater number of earths the same law holds good; thus with m earths. closely allied, to be separated we must have recourse to n—1 different chemical processes. The acid in which the earths are dissolved is nota matter of indifference. There is an objection to sulphuric acid on the ground of its disposition to form double salts, so that of the sulphates in solution a good portion might be double sulphates, in which the two molecules of base combined with one of acid consisted. 586 REPORT—1886. one of one base and one of the other; and the two molecules thus intimately associated might tend to remain together, whether as precipitate or as filtrate. On the whole, I prefer nitric acid, as having little tendency to form double salts, and being easily got rid of. It is occasionally necessary to completely precipitate the whole contents of the bottles with ammonium oxalate, and after ignition to redissolve the earths in acid and proceed as before. If this precaution is not adopted the accumulation of ammonium nitrate in the solution dissolves an appreciable amount of the earths. In the ordinary operations of separating distinct entities, such as the known gadolinite or samarskite earths, it is not difficult, as I have already pointed out, to find different chemical processes, which may be successively employed. When, however, the separations attempted are those of the constituents of yttrium, the ‘simple straightforward fractionation, continued steadily month after month and year after year, is the only plan I know of. The operation may be somewhat hastened by removing from the main series certain bottles in which one particular constituent is concentrated and sub- fractioning these by themselves. Also to avoid the spreading out sideways to too great an extent after a certain distance has been proceeded from the centre, say to bottles —20 and +20: the earths are allowed to accumulate in the last bottle at each end. They will after a time be in sufficient amount to subfractionate on their own account, and, being at the end of the series, they offer a good chance of getting the extreme constituents pretty pure. It will be seen from the above description that there is little hope of success in fractionation unless the supply of crude earths is very large. In my laboratory I have, either worked up or ready for working, over 50 kilos. of samarskite con- taining about 10 per cent. of yttria, and about 20 kilos. of gadolinite containing A8 per cent. of yttria, besides a considerable quantity of other rare yttria minerals, giving a total yield of about 15 kilos. of yttria. 4. On the Fractionation of Yitria.! By Wiuram Crookes, F.B.S., V.P.C.S. Having already explained the methods of chemical fractionation, it is necessary now to describe some of the results yielded by an extended perseverance in these -operations. I must, in the first place, explain that my work has been confined to a limited and very rare group of bodies—the earthy bases contained in such minerals as samarskite, gadolinite, &c. These have been repeatedly put through the fractiona- tion mill by other chemists, but the results have been most unsatisfactory and -contradictory, no sufficiently good test being known whereby the singleness of any earth got out by fractionation could be decided, except the somewhat untrust- worthy one of the atomic weight. I say untrustworthy because it is now known that fractionation, unless it is pushed far beyond the point to which some Conti- nental chemists have even carried it, is quite as liable to give mixtures which refuse to split up under further treatment of the same kind, as it is to yield a chemically simple body. It is well known that a limited group of these rare earths, when phosphoresced in vacuo, yield discontinuous spectra. The method adopted to bring out the spectra is to treat the substance under examination with strong sulphuric acid, drive off -excess of acid by heat, and finally to raise the temperature to dull redness. It is then put into a radiant-matter tube, of the form shown in fig. 1, and the induc- tion spark is passed through it after the exhaustion has been pushed to the required -degree. The phosphorescence occurs beneath the negative pole. Bodies like yttrium sulphate, &c., under the stimulus phosphoresce, emitting light whose waves tend to collect round definite centres of length. The phosphorescent light which the discharge evokes is best seen in a spectroscope of low dispersion, and with not too ’ The original paper was published zn extenso in the Chemical News for September 24, 1886. TRANSACTIONS OF SECTION B. 587 narrow a slit. In appearance the bands are more analogous to the absorption bands seen in solutions of didymium than to the lines given by spark spectra. Examined with a high magnifying power all appearance of sharpness generally disappears ; the scale measurements must therefore be looked upon as approximate only ; the centre of each band may be taken as accurately determined within the unavoidable errors of experiment, but it is impossible to define their edges with much precision. As a general rule, the purer the earth the sharper the band, and when impuri- ties are removed to the utmost extent, the sharpness is such as to deserve the name of a line. To this rule one exception occurs. The body which I have named S6, or 609, is remarkable for the great sharpness of its phosphorescent line, and I have noticed searcely any variation in its sharpness, however large the bulk of extraneous earth associated with it. This line, however, is sharper and brighter when the current is first turned on than it is after phosphorescing for a minute or so. In the Bakerian lecture on yttrium delivered before the Royal Society,’ I described the phosphorescent spectrum given by this element, and in the address which I have had the honour of delivering before this Section I gave a drawing of the spectrum of yttrium, together with a sketch of the train of reasoning by which I had been led to the opinion that excessive and systematic fractionation had split up this stable molecular group into its components, distributing its atoms into several groups, with different phosphorescent spectra. No longer than twelve months ago the name yttria conveyed a perfectly defi- nite meaning to all chemists. It meant the oxide of the elementary body yttrium. I have in my possession specimens of yttria from M. de Marignae (considered by him to be purer than any chemist had hitherto obtained), from M. Cléve (called by him ‘ purissimum ’), from M. de Boisbaudran (a sample of which is described by this eminent chemist as ‘ scarcely soiled by traces of other earths’), and also many specimens prepared by myself at different times, and purified up to the highest degree known at the time of preparation. Practically these earths are all the same thing, and up to a year ago every living chemist would have described them as identical, 7.e., as the oxide of the element yttrium. They are almost indis- tinguishable one from the other, both physically and chemically, and they give the phosphorescent spectra im vacuo with extraordinary brilliancy. This is what I formerly called yttria, and have more recently called old yttria. Now these constituents of old yttrium are not impurities in yttrium any more than praseody- mium and neodymium (assuming them really to be elementary) would be impurities in didymium. ‘hey constitute a veritable splitting up of the yttrium molecule into its constituents. The plan adopted in the fractionation of yttria does not differ in principle from the methods described in my paper ‘On the Methods of Chemical Fractionation.’ Dilute ammonia is added to a very dilute solution of the earth in only sufficient quantity to precipitate one half. After standing for several hours the precipitate » Phil. Trans., Part III. 1883, 588 REPORT— 1886. is filtered. After each fractionation the filtrate is passed to the left and the precipitate to the right, and the operations are continued many thousand times. The diagram (fig. 2) shows the scheme clearly, with the direction the precipi- tates and solutions travel. Limited space, even on a large diagram, prevents me from giving more than a few operations, but they will be sufficient to satisfy you that enormous patience, a large amount of material, and a not insignificant number of bottles, are requisites for successful fractionation. After a certain time, on examining the series of earths in the lowest line of bottles, their phosphorescent spectra are found to alter in the relative intensities of some of the lines, and ultimately different portions of the frac- tionated earths show spectra, such as I have endeavoured to illustrate at the foot of the diagram (fig. 2), in which I have given the spectra of five com- ponents of yttrium. @) & aa a os ate Q EK & &, 8. oS 6) ohel Se A XX ee ER EOI Ded oe < ee ee PrieX LAE zicvcl @. oe = eNcee O) es VC) BSL. BAB! QB SSC COTS ST SSIS SETS Qo it HTH MW OM Leetmds OF FIVE COMPONENTS YTTRIA Fie, 2 The final result to which I have come is that there are certainly five, and probably eight, constituents into which yttrium may be split. Taking the con- stituents in order of approximate basicity (the chemical analogue of refrangi- bility) the lowest earthy constituent gives a deep blue band Ga (A 482); then there is a strong citron band Gd (A 574), which has increased in sharpness till it deserves to be called a line; then come a close pair of greenish blue lines, GB (A 549 and \ 541, mean 545); then a red band, G¢ (A 619), then a deep red band, Gy (A 647), next a yellow band, Ge (A 597), then another green band, Gy (A 564); this (in samarskite and cerite yttria) is followed by the orange line Sé (A 609). The samarium bands remain at the highest part of the series. These, I am satisfied, are also separable, although for the present I have scarcely touched them, having my hands fully occupied ‘with the more easily resolvable earths. The yellow band, Ge, and green band, Gy, may in fact be due to a splitting up of samarium. Until we know more about these bodies I refrain from naming them, but will designate them provisionally by the mean wave-length of the dominant band. If, however, for the sake of easier discussion among chemists a definite name is thought TRANSACTIONS OF SECTION B. 589 to be more convenient, I will follow the plan frequently adopted in such cases, and provisionally name these bodies as shown in the following table :— Scale of | Bs g ies ate Rowe: Scale o: Rpeie rO- Position of pitas in the spectro- | 7S x al visional Probability EDeCorum scope g Ao ~ name Shs | Bright lines in— Deep blue 3 7 4 8931 482 4304 Ga New. Greenish blue (mean aa; 9:650 545 3367 Gp { New, or the Zp of M. de a close pair) . | Boisbaudran, Green - 2 . 5 9812 564 3144 Gy New. 7 4 . New, or the Za of M. de Giron... 9880 574 3035 Gs { lark ey Yellow 4 A «| 10:050 597 2806 Ge New. Orange . : 2 - | 10°129 609 2693 sé New. Red . . 5 . . 10°185 619 2611 G¢ New. | Deep red . - | 10338 647 2389 Gn New. The initial letters S and G recall the origin of the earths respectively from samarskite and gadolinite. Not only has yttrium been split up by subjection to fractionation, but samarium, as I have hinted above, is likely to prove equally unable to resist this operation. In the phosphorescent spectrum of samarium sulphate the line Sé (609) is one of the constituents. When yttria is added to samaria this line is developed in greater intensity, as yttria has the power of deadening the other bands of samarium, while it does not seem to affect the line Sd. Several circumstances, however, tend to show that although line Sd accompanies samarium with the utmost pertinacity it is not so integral a part of its spectrum as the other red, green, and orange lines. For instance, the chemical as well as physical behaviour of these line-forming bodies is different. On closely comparing the spectra of specimens of samaria from different sources, line 86 varies much in intensity, in some cases being strong and in others almost absent; the addition of yttria is found greatly to deaden the red, orange, and green lines of samarium, while yttria has little or no effect on the line $6; again, alittle lime entirely suppresses line Sd, while it brings out the samarium lines with increased vigour. Finally, attempts to separate line Sd from samarium and those portions of the samarskite earths in which it chiefly concentrates has resulted in sufficient success to show me that, given time enough and an almost in- exhaustible supply of material, a separation would not be difficult. These facts, together with the peculiar behaviour of the lines Ge and Gy, strengthen my sus- picion as to the resolvability of samarium. Samaria giving the line Sd has been prepared from cerite and samarskite. Many observations have led me to think that the proportion of band-forming con- stituents varies slightly in the same earth from different minerals. Amongst others, gadolinite showed indications of such a differentiation, and therefore I continued the work on this mineral. Very few fractionations were necessary to show that the body giving line Sé was not present in the gadolinite earths, no admixtures of yttria and samaria from this source giving a trace of it. It follows therefore that the body whose phosphorescent spectrum gives line SS occurs in samarskite and cerite, but not in gadolinite. It now became an interesting enquiry whether all these constituents of yttrium were united together in exactly the same proportion in every case. A glance at the diagram before you will show that yttrias from different sources, although they may be alike as far as our coarser chemical tests are concerned, are not built up exactly in the same manner. Thus, when the samarskite yttrium was forming, all the constituent molecules—which 1 have provisionally named Ga, GB, Gy, G6, Ge, Gg, Gn, and Sé—condensed together in fair proportion. In gadolinite yttrium the constituents G8 and Gé are plentiful, G¢ is very deficient, Sd is absent, and the others occur in moderate quantities. In the yttrium from xenotime G8 is most plentiful, G8 occurs in smaller proportion, G¢é is all but absent, and Sé is quite absent. Yttrium from monazite contains G@ and God, with a fair proportion _ 590 REPORT—1886. of the other constituents, G8 is plentiful and the red is good. Yttrium from fluocerite is very similar to that from monazite, but Ga is weaker. Yttrium from hielmite is very rich in G6, has a fair quantity of Ga and G8, less of Gy, no Sd, and only a very faint trace of Gy. Yttrium from euxenite is almost identical with that from hielmite. Yttrium from cerite contains most G¢ and G6, less Ga and GB, only a trace of Gy, and a fair proportion of S6é. Referring to the diagram it is seen that Ya (gadolinium) is composed of the following band-forming bodies :—Gf, 85, Gé, together with a little samarium. Calling the samarium an impurity, it is thus seen that gadolinium is composed of at least three simpler bodies. You have probably anticipated in your minds a question which is likely to occur at this point of the enquiry. If such results have been obtained by sub- mitting yttrium to this novel method of analysis, what will be the result of fractionating some other reputed element ? Yttrium, as I have explained, is an exceedingly stable molecular group, capable of acting as an element, just as calcium, for instance, acts as an element: to split up yttrium requires not only enormous time and material, but the existence of a test by means of which the constituents of yttrium are capable of recognition. Had we tests as delicate for the constituent molecular groups of calcium, this also might be resolved into simpler groupings. It is one thing, however, to find out means of separating bodies which we know to be distinct and have colour or spectrum reactions to guide at every step; it is quite another thing to separate colourless bodies which are almost identical both in chemical reaction and atomic weight, especially if we have no suspicion that the body we are dealing with isa mixture. One of the chief difficulties in the successful carrying out of an investigation in radiant-matter spectroscopy is the extraordinary delicacy of the test. This extreme sensitiveness is a drawback rather than a help. To the inexperienced eye one part of yttrium in ten thousand gives as good an indication as one part in ten, and by far the greater part of the chemical work undertaken in my hunt for spectrum- forming elements was performed upon material which later knowledge shows did not contain sufficient to respond to any known chemical test. It is as if the element sodium were to occur in ponderable quantity only in a few rare minerals seldom seen out of the collector’s cabinet. With only the yellow line to guide, and seeing the brilliancy with which an imponderable trace of sodium in a mineral declares its presence in the spectrum, I venture to think that a chemist would have- about as stiff a hunt before he caught his yellow line as I have had to bring my orange and citron bands to earth. Chemistry, except in a few instances, such as water-analysis and the detection of poisons, where necessity has stimulated minute research, takes little account of ‘traces,’ and when au analysis adds up to 99999, the odd 0-001 per cent, is conve- niently put down to ‘impurities,’ ‘loss,’ or ‘errors of analysis.’ When, however, the 99999 per cent. constitutes the impurity and this exiguous 0-001 is the precious material to be extracted, and when, moreover, its chemistry is absolutely unknown, the difficulties of the problem become enormously enhanced. Insolubility as ordinarily understood is a fiction, and separation by precipitants is nearly impos- sible. A new chemistry has to be slowly built up, taking for data uncertain and deceptive indications, marred by the interfering power of mass in withdrawing soluble salts from a solution, and the solubility of nearly all precipitates when present in traces in water or in ammoniacal salts. What is here meant by ‘ traces’ will be better understood if I give an instance. After fifteen months’ work I obtained the earth yttria in a state which most chemists would call absolutely pure, forit contained not more than one part of impurity (samaria) in two hundred and fifty thousand parts of yttria. But this one part in a quarter of a million pro- foundly altered the character of yttria from a radiant-matter-spectroscopie point of view, and the persistence of this very minute quantity of interfering impurity entailed another ten months’ extra labour to eliminate these final ‘traces’ and to ascertain the real reaction of the earth called yttria. TRANSACTIONS OF SECTION B. 591 5. On the Colour of the Oxides of Cerium and its Atomic Weight.! By H. Rostnson, M.A. This paper was principally a criticism of Wolf's paper on the atomic weight of cerium, published in the ‘American Journal of Science and Art,’ 1868. Great prominence is given to this work in Clarke’s ‘Constants of Nature.’ Wolf's ceric oxide was white, and the atomic weight of the metal was 137°, or, as recalculated by Clarke, 138°. The writer of the present paper contended that Wolf’s method. of separation was wrong—that it would not give ceric but lanthanum oxide, which is white, and which contains a metal with an atomic weight lower than that of cerium. Wolf's method of separation was repeated fractionation of impure cerous sulphate by gentle evaporation. Robinson made similar experiments and found the proportion of Ce,O, to La,O, decreased from 4 to 1 to 2 to 1 by making the same number of crystallisations Wolf had done. He also found that at the temperature of the evaporation, 65°, 100° cc. of water held in solution 10-296 grains of Ce,550,, while under the same conditions only 2:106 grains of La,3SO, remained in solution in the same quantity of water. He maintained the colour of ceric oxide is not white, as is sometimes supposed, but a pale sulphur yellow, and that the atomic weight of cerium is 140°2,as found by himself and also by Branner. 6. On the Determination of the Constitution of Carbon Compounds from Thermo-chemical Data. By Professor Armsrrone, F'.R.S, 7. On the relative Stability of the Camphene Hydrochlorides C,,H,,Cl ob- tained from Turpentine and Camphene respectively. By Ernest F. EHRHARDT.? Riban has shown that the former of these bodies is less easily decomposed by water ; the author shows that it is also more stable under the influence of heat. Tilden has shown that at a low red heat turpentine breaks up more completely than camphene; the author extends this observation to lower temperatures, by observing the vapour densities in a bath containing melted lead. The paradoxical result that the hydrochloride from the stable hydrocarbon is less stable than that from the unstable one is held to prove that this is a ‘ molecular’ compound, the chlorine in it remaining associated with the hydrogen of the acid, while at the same time being attached to the hydrocarbon. 8. On Derivatives of Tolidin and the Azotolidin Dyes. By R. F. Rurran, B.A., MD. Tolidin and its older homologue benzidin have only quite recently become prominent, owing to the discovery of the so-called azo-colours. Benzidin was first prepared by Zinin, in 1845,° and its mode of formation from hydrazobenzene described by Hafman* Schultz°* established the now accepted formula for this base, and investigated many of its reactions. Tolidin was prepared in an analogous way to benzidin, but its reactions were not studied. Petriew,® who was the first to obtain orthotolidin, only in small quantity, however, gives the melting-point 112°. This is too low; the proper melting-point is 127-128°. Generally this base resembles benzidin very closely in its behaviour, but differs considerably from toluidine. It forms with mineral acids two series of salts, the acid salts being the more in= soluble. It gives a play of colours from green to blue, finally scarlet, on dropping 1 Published in eaxtenso in the Chemical News, vol. liv. p. 229. 2 Chemical Nens, November 13, 1886. * Journal fiir practische Chemie, xxxvi. p.93. * Jahresberichte, 1863, p. 424. 5 Luby’s Annalen, p. 174. & Berichte, vi. p. 557. 592 REPORT—1886. a dilute aqueous solution of bromine in an alcoholic solution of the base. It forms a soluble monacetyl and an insoluble diacetyl derivative in form of silky needles. The hydrogen of the amidogen groups may be replaced by two or four methyl groups forming secondary bases resembling tolidin, and melting at 69° and 81° respectively. Further union with methyl iodide gives the ammonium salt, crystallising in red needles, from which the hydrate may be obtained by silver oxide. With chloroform by no experiment could even traces of an isocyanide be obtained. Carbon disulphide forms a thiourea but yields no isosulphocyanide. The base unites directly with cyanogen to form a dicyanogen compound of red colour and very insoluble. With urea it unites directly, evolving ammonia, forming a com- pound urea. The same substance can be obtained with phosgene gas, hydrochlorate of tolidin being simultaneously formed. The dinitrodiacetyl crystallises in yellow needles, soluble in hot nitrobenzol. Strong caustic potash forms from this the nitrotolidin in red plates soluble in alcohol. Nitrous acid gives a tetrazoditolyl from which all the azotolidin colours are derived. Their general formula may be represented by CH,-C,H,-N=N-R CH,-(,H,-N=N-R where R represents more or less complex aromatic acids or their sodium salts. Thus in Congo red, R is the sodium salt of naphthylaminesulphonie acid; in chrysarine yellow it is sodium salicylate; in azo blue B-naphtholsulphonic acid. These colours are peculiar, in that they alone of all the artificial dyes are capable of dyeing cotton and wood fibre directly, 7.e., without the intervention of a mordant. Cotton fibre boiled in tolidin hydrochlorate, washed, dried, and dipped first in dilute nitrous acid, and then in some of the above acids is permanently coloured of particular dye formed by that acid, thus showing that the tolidin probably unites with the oxycellulon of the cotton, and so acts asa mordant. This is rendered further probable, as when once dyed by one of these colours cotton fibre will form mixed colours directly with such basic dyes as fucsin, methyl blue, &e. TUESDAY, SEPTEMBER 7. The following Papers were read :— 1. On the Treatment of Phosphoric Crude Iron in Open-hearth Furnaces. By J. W. Waites. The great importance of a process dealing with phosphoric iron must be measured by the extent of the deposits of ore yielding phosphoric pig. These deposits in Europe exceed by ten or twelve to one the deposits of ore yielding purer The amount of phosphorus that can be allowed in finished steel may be taken at not more than one tenth per cent., though this is more by about half than manufacturers care to deal with. The softer and purer kinds of steel, where great ductility is required, should contain as little phosphorus as possible, the effect of this element being to render iron and steel brittle at ordinary temperatures. A description of puddling was then given (illustrated in the diagrams), showing the furnace and the reactions that take place during the process, and it was con- tended that the manual labour of puddling was rendered necessary by the limited range of heat obtainable in puddling furnaces, which is not sufficient to retain iron after it has parted with a large proportion of its alloys in a molten condition, so that the metal has to be removed from the furnace in a spongy state. A com- parison was then drawn between the process of purifying phosphoric iron by TRANSACTIONS OF SECTION B. 593 puddling and the results obtained in the ‘ Batho furnace,’ an improved form of the Siemens regenerative furnace. It was shown that the Batho furnace was reduced to a simple mechanical contrivance, and that the idea of a furnace as a building had been entirely abandoned. The means of applying the basic lining to the simplified furnace, which consists of detached regenerative stoves and a melting-vessel, connections between the two being made by means of tubes lined with heat-resisting material. The basic lining is mixed with short fine wire, which is used like hair in plaster on ordinary walls, simply to keep it from cracking and falling off. It was pointed out that the difficulty of applying a basic lining to a vessel of this kind is reduced to a minimum. The process of treating phosphoric crude iron in this vessel was then described, and reactions given similar to those obtained in the puddling furnace, but more erfect as a natural result of a more perfect heat, producing more perfect reactions. stead of the metal being drawn from the furnace in a spongy state, it is run out into moulds, fluid and in a more highly refined condition. Comparison was made with the Bessemer basic process, and it was shown that in this process the oxidising base necessary had, in a large measure, tc be obtained by the oxidation of part of the metallic charge, whereas in the open-hearth treat- ment the oxide is put in the furnace as oxide. It was pointed out that the purest homogeneous iron was not in one respect equal to the produce of the puddling furnace. If highly-wrought iron, like a patent faggoted axle, be subjected after it is superficially cut with a sharp tool to the shock of a falling weight, it will only open to the depth of the cut—the fibre of the metal opening at this point—whereas the purest steel under similar treatment, not having this fibre, would break. In conclusion, it was stated that the open-hearth process described did not so much supersede puddling as render the manual labour unnecessary, and by natural reaction, under more perfect heat, arrive at a more perfect result. 2. On the Basic Bessemer Process in South Staffordshire. By W. Horcuinsoy. On account of the great importance of the successful application of a dephos- phorising process to South Staffordshire iron, Mr. Hutchinson was requested to give an account of the procedure at the works of the South Staffordshire Steel and Ingot Tron Oo, The account included an analysis of the dolomite used in making the basic lining, and a description of the preparation of the lining, together with the basic bricks and converted bottoms. A short description of the process was given. On account of the siliceous character of the metal used it is first blown for a short time in a Bessemer vessel with acid lining, and after partially desiliconising it is transferred to the basic vessel, where the removal of the phosphorus is effected. Analyses were given of the iron before and after desiliconising, and also of the finished product. An account was given of the mechanical tests adopted and of the branches of manufacture for which the material is particularly adapted. The paper concluded with a reference to the basic slag produced during the process. 3. On the Production of Soft Steel in a new type of Fixed Converter. By Georce Harton. Large and costly plants hitherto generally employed for steel-making being beyond the reach of many iron manufacturers having existing works which they might wish to adapt for steel-making, some rapid and continuous method of steel- making involving only moderate expenditure on plant has long been desirable ; and the fixed converter offers many advantages in this direction. Referring to Sir Henry Bessemer’s use of a fixed converter, and the subsequent use of such converters in Sweden, the paper points out the great difficulty always attending the use of fixed converters of the old type, namely, the necessity for 1886. QQ 594 REPORT—1886. maintaining a current of blast through the tuyeres after the blow was finished and during the process of tapping, producing undesirable oxidation of the metal, and describes M. Wittndfftt’s suggestions for dealing with the difficulty, also the Clapp and Griffiths differential piston valve for closing up the backs of the tuyeres. The type of converter as constructed by the writer at Bilston is next described. It consists of a vessel, not unlike an ordinary Bessemer vessel in outward shape, supported and rigidly fixed on four cast-iron columns ; the lower section, containing the charge of metal, having tuyeres through the sides and a solid bottom of silica bricks, is removable, and can readily be replaced by means of a hydraulic ram, which raises it into position or lowers it for removal, as required. The blast boxes are fixed around the casing of the upper section in a position above the metal-line, connection from these to the tuyeres being through cast-iron down pipes, each fitted with a ‘baffler’ valve (one to each tuyere). ‘These valves are simultaneously closed at the termination of the blow, a small hole through each valve admitting enough blast to support the metal in the converter and keep it out of the tuyeres. It is claimed that softer and more reliable material is obtained in this vessel than in the ordinary Bessemer one. Owing to the action being less violent, there is less risk of oxidation, as the final changes take place less rapidly ; as, instead of the whole bath being constantly penetrated and oxidised—as in the bottom-blown vessel—only about a third of the charge is under treatment at once, a further indirect process of oxidation at the same time being carried on by circulation and admixture of the oxidised iron with the remaining portion of the bath. This converter has an advantage over small Siemens plants, inasmuch as soaking pits can be used. Some analyses are given both of soft steel produced and of steel castings, for the manufacture of which this converter is well adapted. 4, The Influence of Remelting on the Properties of Cast Iron. By Tuomas TURNER. In the ‘ Report of the British Association’ for 1853 (p. 87) an account is given of an elaborate series of experiments undertaken by Sir William Fairbairn to ascertain the effect of remelting on the mechanical value of cast iron. The metal used was Eglinton hot blast grey iron, which was melted 18 times in an air furnace, tests being performed at each remelting. It was found that the material gradually improved up to the 12th melting, then rapidly deteriorated, becoming white, hard, and weak at the 18th melting. The following analyses, given in the original paper, are due to Professor Calvert :— Percentage of No. of Meltings Si ) 1 O77 0°42 2°76 8 1:75 0°60 2°30 10 1:98 0:26 3°50 18 2°22 0-75 3-75 These experiments have been largely quoted in the principal works on engineer- ing, metallurgy, and technical chemistry, and various suggestions have been made to account for the effect observed, and the absence of any apparent connection between chemical composition and mechanical value. The author has examined specimens of the original bars, belonging to Professor Unwin, who assisted in these experiments. The identity of the specimens is fully assured, and the results obtained have been confirmed by separate analyses per- formed by Mr. J.P. Walton. In six cases also Professor Unwin retains sufficient for examination at any future time, if such should be necessary. The author’s results are as follows :—? 1 Journ. Chem. Soc, 1886, p. 493. TRANSACTIONS OF SECTION B. 595 of Meine Total Carbon Combined Silicon | Sulphur | Manganese| Phosphorus 1 2°67 0:25 4°22 0:03 17m pee 8074-7 8 2:97 0:08 3°21 0:05 0:58 0°53 12 2°94 0°85 2°52 011 0°33 0°55 14 2°98 1°31 2°18 0:13 0:23 0°56 15 2°87 1:75 1:95 0:16 O17 0°58 16 2°88 Varied in parts} 1°88 0:20 0:12 0-61 These numbers are entirely different from those given by Calvert, but they sup- port the suggestions of Snelus* relative to chemical changes during remelting. 5. Silicon in Cast Iron. By THomas Turner. The author has prepared samples of cast iron containing various amounts of silicon, and has examined the properties of the product.* Cast iron of exceptional purity was prepared by heating wrought iron with charcoal, and to this different ‘quantities of silicon pig were added. The chemical composition of the materials used was as follows :— Description Total Carbon Graphite Si P Mn s | Original Cast Iron . 1:98 0°38 0-19 | 0:32 | 0:14 | 0:05 Silicon Pig : : 1:81 1:12 9:80 | 0-21 | 1:95 | 0:04 The mixtures obtained were examined both chemically and mechanically, and ‘the results are given in the accompanying table. The tensile and crushing strength was determined by Professor A. B. W. Kennedy, while for assistance in the chemical analyses the author is indebted to Mr. J. P. Walton. It will be seen that the addition of silicon to white iron causes the separation of graphitic carbon, and produces a grey iron. The effect is therefore to soften the iron. By suitable addition of silicon an iron of any desired softness may be pre- pared without extra expense, and the author believes that with care in mixing the strength of cast iron could readily be doubled in many cases. A number of manu- facturers have already applied the conclusions deduced from these experiments with very beneficial results. As illustrating the practical value of these researches, the author referred ta the work of Mr. C. Wood, who has been using siliceous iron in the foundry with marked ‘success during the past twelve months. By this means Mr. Wood is able to prepare castings with a uniform tensile strength of 12 tons per square inch, using entirely Middlesborough iron. He is also able to make perfectly soft, smooth, sound castings, and to obtain grey iron even in sheets not exceeding one-eighth of an inch ‘in thiclmess. The author has recently had an opportunity of performing some experiments at the Rosebank Foundry, Edinburgh. Of these, and of other results obtained at this foundry, he hopes to give an account shortly. In the meantime he takes the oppor- tunity to say that his former conclusions are quite confirmed. Six-test pieces of ‘cast iron were exhibited with tensile strength varying from 15:8 to 18: tons per square inch, the average being nearly 17 tons; a result which, so far as the author is aware, has never before been obtained with British cast iron. These samples were not unusually hard to the tool, and the author believes that at such results as these the founders connected with our leading engineering works should aim. 1 Journal Tron and Steel Institute, vol. i. p. 37. 2 Jour. Chem Soc. 1885, pp. 577, 902; 1886, p. 130. Journ. Iron and Steel Insti- tute, 1886, Part I. TZvron, xxvii. p. 476. Jour. Soc. Chem. Industry, 1886, p. 289. aq2 ‘solIos oY4 Ut wortsod S}t Mory popedroryjue oq qq stu $0} 09 Hoge Jo qSues Surysnio vf ysiq Aqreuondeoxo ATquqoad st osvo sty} ULenTwA syy, z “A}NVI YBYMouIOs aq 0} padoid sprvasejje Uottoads o1} SB ‘MOT IOYYVI SI JOQuINU sIyy, 7 ee SS ee eS 1886. REPORT 596 40:0 | 96-1 | 12-0 | 08-6 | 69-0 | ZI-T | 18-T | 699-0] 693'T | OT-FE | O8e‘9L | O00‘OEEST | GL-F | Of90T| 2g F069 | 816-9 | OT €0-0 | 98-1 | 6-0 | e8-2 | 88-0 | 8F-1 | 98-1 | 229-0] 90S‘T| ¢9-6F | OOO'TIT | OOO‘OSL'FI | FE-9 | OGETT| ZF SET-L | 83T-L | 9-2 90:0 | 96-0 | 08-0 | FL-F 16-0 | 99-T | €0-6 | 9F0-1 | GPSS | 9T-9F | OOFGOT | OOOOSL*ST | 9T-OT| OSL°S| BE OLT-L | L9T-L | 9 60:0 | #80 | &&-0 | G6-E | 08-0 | 18-1 | 10-6 | get-1] ef9°S | FL-LF | 006‘90T | OOO‘OFO'ST | 8Z-IT | 08a'Es| 12 816-2 | §8.-L | F 0-0 | O10 | 48-0 | 96-6 | 08-0 | SFT | €-6 | G1z-1 | 098'S| SF-LE] OOL*BZT| OOO'OSTIS | 6-31 | O6E'LG| GE | GGL | B9GL] & 90-0 | 91:0 | 96-0 | 19-6 | 89-0 | 6I-T | 28-1 | .LL¢-1]2F89°E | 28T-LL|2006°SLT| O00‘OSF'GS | G9-FI | O9L‘SE| 3S 888-2 | GaF-L 9-4 £0-0 | 09-0 | 86-0 | 96:1 | 94-0 | G9-I | 81-8 | gee.1 | OFFS | 63-19 | OOE'LET | 000‘09GES | OL-ST | OST’SE| Bz ose-L | 819-2 | 2 20-0 — | 0&0 | 28-1 | TILT | 08-0 | 16-6 | T9g-1 | S6F‘E | 80-68 | OOG'EST | 000'00S'ES | FO-FT | OFFTE| — GLP-L | 999-2 |F-0 40:0 | 96-0 | &€0 | 96:0 | 98. | ¥Z-0 | 60-6 | 409-1 | OLE'S | F9-46 | 00E'L04 | OOOOST'IE | GL-GI | 0648) GF 069-2 | TOL | T 20-0 | 16-0 | &&0 | 24-0 | 06-T | OT-0 | 00-6 | FOF-1 | 084'E | BF-16 | 008‘FOS | 000'0L9'8S | TE-GI | 08926] 39 OL9-L | 1012-2 | 4.0 20-0 | FL-0 | GE-0 | 61-0 | O9T | 8E-0 | 86-T | 902-1 | ZOL‘S | O8-E2| OOL‘S9T | 000‘OGL'SS | FI-OT | OZL°SS| GL 6IL-2 | 099-2 | 0 suo} Sq] suo} “Sq suod "SqI inyd | asauvs) snaoyd uodTTTS earn ayiqd j|UoqIed aya 3 ssummainy, | tapurpAp pa -Ing |-uey | -sogg -woy | PD T810L | oy3 ur pepeoy = $8 ‘grenbs Tout T youy erenbg AOYSel youy srenbg 5 =e) ‘Buoy yy Tsavg| sod 1Suayg jo Jod = yysueryg B° |(Cq=o0¢qe 1078) | ES “yysuayg Surysnip sn[npoyw aqisuay, eet pus a YOM 3 5 SISLIVNY IVOINGH OSIOAUBLT, ) =) a : Vv fe) Pome, a qe AjIstiagy eAryv [0% at ‘NOUT ISVO JO SaIwuadoOug AHL NO NODITIG AO LOdday— Y Adv], TRANSACTIONS OF SECTION B. 597 In connection with Mr. A. E. Jordan, the author has also examined the condi- ‘tion of silicon in cast iron, and concludes, with Snelus and others, that in the vast majority of cases at least, silicon does not occur in the graphitic form. He believes it to be present in the form of silicide. Recently Dr. Sorby has observed by means of the microscope minute crystals in cast iron, which he believes to be silicon. The author does not consider the evidence in support of this opinion to be conclusive as yet, and contends that, even if these minute crystals should prove to be silicon, in their chemical behaviour they more closely resemble that element in the amor- phous than in the graphitic condition. 6. The Influence of Silicon on the Properties of Iron and Steel. By Tuomas TURNER. The following is a preliminary account of a series of experiments the completion of which will probably occupy several years. The object in view is to determine the influence of silicon on the mechanical properties of steel as used either for castings or tools, and also on the purest kind of iron met with in commerce. For the present experiments, which were conducted at the works of the South Staffordshire Steel and Ingot Iron Company, Bilston, iron was taken by means of a small ladle from the Bessemer converter just after the blow was finished, and before any addition of manganese had heen made. It was therefore very nearly pure iron, containing not more than one quarter of a per cent. of all substances other than iron. This material was poured into a red-hot crucible of Stourbridge fire- clay, and in which was placed a weighed quantity of silicon pig iron containing 10 per cent. of silicon. After being well mixed together the contents were allowed to solidify in the pot and afterwards examined. The material was originally rather redshort owing to the absence of manganese, but redshortness did not seem to be at all diminished by a small addition of silicon, and before 0:2 per cent. was reached the metal went to pieces on attempting to roll it red hot. The metal appears to weld equally well with all proportions of silicon which are capable of being rolled, andis very tough when cold. A few hundredths per cent. of silicon caused the metal to remain much quieter on pouring, while about half a per cent. conferred the property of hardening in a remarkable manner. A chisel prepared from this material was very tough cold, and retained its cutting edge very well indeed, and giving a fracture much resembling tool steel. It was how- ever very difficult to work while hot. The author hopes to be able to give fuller details in a few months. 7. On the Estimation of Carbon in Iron and Steel.! By THomas TURNER, The author dissolves from three to five grams of borings in ammonio-copper chloride for the determination of total carbon, or in hydrochloric acid for estima- tions of graphite. The carbon in the residue is estimated by combustion. The A. Potash Tube. C. Drying Tube. B. Combustion Furnace. D. Potash Bulbs. 1 Proceedings Birmingham Philosophical Society, vol. iv. Part II. p. 404. Chem. News, lii. p. 15. Tron, xxvi. p. 84. 598 REPORT— 1886. apparatus for this operation is extremely simple, while the operation itself is rapid, and avoids transference of the carbonaceous residue. Filtration is effected in a short: piece of combustion tubing, narrow at one end, and fitted with a filter of ignited sand and asbestos. After drying, combustion is performed in the same tube by Filter and Combustion Tube. means of a yery simple combustion furnace, the cost of which is trifling, and whick stands on an ordinary working bench. The furnace has also been found useful for a yariety of other uses in the laboratory. Sketches of the apparatus are annexed. WEDNESDAY, SEPTEMBER 8. The following Reports and Papers were read :— 1. Report of the Committee on Isomeric Naphthalene Derivatives.— See Reports, p. 216, 2. Report of the Comiuvittee for preparing a new series of Wave-length Tables of the Spectra of the Elements.—See Reports, p. 167. 3. On the Chemistry of Estuary Water. By Hues Rosert Mun, D.Sc., F.R.S.H., FCS. Although chemical problems connected with ocean water and oceanic deposits have been attacked by Forchhammer, Dittmar, and others, while recently Norwegian and German investigators have done much to elucidate the conditions obtaining in enclosed and partially enclosed seas, the chemistry of estuary water has been com- paratively neglected. In investigating an estuary the first essential is to ascertain the salinity (ratio of total dissolved matter to water), from point to point, and to trace its variations ; the second to perform accurate analyses of the saline and gaseous contents at various positions suggested by the previous salinity observations. The first of these has been done completely for the Firth of Forth, and partially for the Firth of Clyde and some other river entrances in Scotland; the second is in progress. By means of the hydrometer (form used by Mr. Buchanan on the Challenger Expedition) the distribution of salinity in the Firth of Forth has been proved to be nearly constant all the year round, while that of the Firth of Clyde is subject to periodical variations through the whole mass of water. The conclusion drawn from the form of the density (salinity) curve for the Forth river-entrance is that mixture of river and sea water takes place by a true process of diffusion which produces and maintains a constant (though not uniform) gradient of density from river to sea. Possibly the different diffusive powers of the various potential compounds, the constituents of which exist in solution, may determine the formation of certain salts, and lead to the preponderance of these in certain places. The truth of this hypothesis will be tested by the second part of the inquiry, which is now being commenced. Observations of alkalinity by the method of Tornoe showed a marked increase of the (potential) calcium carbonate in solution with decrease of salinity, ¢.e., the dissolved matter of fresher water was richer in calcium carbonate than that of sea- water, TRANSACTIONS OF SECTION B. 599 4, The Essential Oils: a Study in Optical Chemistry. By Dr. J. H. Guapstone, F.B.S. 5. An Apparatus for maintaining Constant Temperatures up to 500°. By G. H. Bamey, D.Sc., Ph.D. The apparatus consists of a tube of hard glass, 25 em. long and 4 cm. in diameter, placed horizontally over a furnace of 6 Bunsen burners, and enclosing a smaller tube in which substances may be heated. Alongside this is the bulb of an air-thermometer, which connects with a U-tube containing mercury. On heat- ing, the mercury column is of course depressed in the near limb of the U-tube, and rises in the further limb, the amount of the depression being indicated by a millimetre scale. The instrument is first graduated by placing a high boiling thermometer in the heating tube, and then constructing from the readings a curve, by reference to which the temperature may be ascertained when the reading on the scale is known. The gas supply passes through a tube fitting into the further limb of the U-tube arranged as a gas regulator, so that, as the mercury rises in this limb, it cuts down the supply. By raising or depressing this regulator the point at which the supply is cut off is determined, and any desired temperature can thus be maintained in the heating tube. The apparatus has been found reliable up to 500°, and it is possible to measure the temperature with great accuracy, and to keep it constant within at most 5° with the greatest ease. The author suggests its use for determining the temperature of decomposition of salts, melting-points, and for investigations in dynamical chemistry. 6. On a new Apparatus for readily determining the Calorimetric Value of Fuel or Organic Compounds by Direct Combustion in Oxygen. By Wiuiam Tomson, F.R.S.L. This consists of an arrangement by which the organic substance is burned in a small platinum crucible, set in a non-conducting cup or holder, the whole being enclosed by a thin glass inverted test-tube, and the combustion performed under water. The stream of oxygen is directed on to the burning material by a movable narrow brass tube, so that the combustion is absolutely under control. By this means plumbago or anthracite may be easily and perfectly burned, which cannot be done by the apparatus devised by Mr. Lewis Thompson, which consists in burning the material by means of a mixture of chlorate and nitrate of potash. This last arrangement gives inaccurate results and is unscientific, inasmuch as there are many things which modify the results which cannot be measured, and which vary in each experiment. The gases from the combustion in oxygen pass through water contained in a long thin glass beaker; the glass, platinum, mercury, and brass work used in the apparatus is weighed, and from their specific heat their equivalent in water is calculated—2,000 grammes of water are used for 1 gramme fuel. 7. On some Decompositions of Benzoic Acid. By Professor Opune, F.R.S. 8. The Crystalline Structure of Iron Meteorites. By Dr.O. W. Huntineton. The object of this paper was to show that the true iron meteorites have a common crystalline structure, varying only in details, and not in general character.. In the first place it is shown that the Widmanstittian figures and the Neumann lines are simply the effects of the segregation of impurities during the process of crystallisation parallel to the planes of crystalline growth, and are phenomena similar in all respects to those observed in the crystals of many minerals. It appears that the Widmanstiittian figures, though presenting additional 600 REPORT—1886. features which cannot be discovered in the Neumann lines, grade into the latter by such insensible steps that no natural division can be made between the two classes of phenomena. It is shown also that the plates, of which both the figures and the lines referred to are sections, are always parallel to faces of one of the three fundamental forms of the regular system, the octahedron, dodecahedron, and cube, and that the complications observed are only due to twinning. Figures were drawn illustrating these points, and representing Widmanstiittian plates in all the positions described. It is further shown that the planes of fracture frequently observed in the iron meteorites are also parallel to the faces of the same three fundamental forms. Such fractures have, in most cases, resulted from the concussion produced by the rapid passage of the meteorite through the air, but may also at times be obtained artificially, and differ in no respect from true cleavage planes, except in so far as the malleability of the metal prevents us from developing the cleavage in the usual way. This cleavage is distinguished from the jointed structure, sometimes result- ing from the segregation of impurities and corresponding to the Widmanstattian figures. It appears markedly in some of the most compact meteorites, and often crosses the Widmanstittian plates. Finally, the close agreement of these phenomena with what has been observed in the artificial crystallisation of iron and other materials is pointed out. This investigation throws no new light upon the origin of meteorites, except so far as it strengthens the opinion that the process of crystallisation must have been extremely slow. The occurrence of large masses of native iron occluding hydrogen gas, and containing nickel, cobalt, phosphorus, sulphur, &c., implies a combination of conditions which the spectroscope indicates as actually realised in our own sun and in other suns among the fixed stars, and the most probable theory seems to be that these masses were thrown off from such a sun, and that they very slowly cooled, while revolving in a zone of intense heat. 601 SECTION C.—GEOLOGY. PRESIDENT OF THE SEcTION—Professor T. G. Bonney, D.Sc., LL.D., F.R.S., F.S.A., F.G.S. THURSDAY, SEPTEMBER 2. The President delivered the following Address :— I nave felt it a great honour and an especial pleasure to be asked to preside at the meeting of Section C in Birmingham. A great honour, because of the repute of my predecessors; an especial pleasure because, as born in the Midlands, I am naturally proud of the Midland metropolis, its intellectual activity, and its com- mercial enterprise. Besides this there are few towns in England where I number more friends of kindred tastes than in Birmingham. Geology especially seems to thrive in this district, and little wonder when you reckon among your residents, in addition to a host of other workers, such leaders as Crosskey, malleus erraticorum, Allport, who taught me how to work with the microscope, and Lapworth, to whose genius my duller mind is under constant obligation. The addresses delivered at the annual meetings of the British Association afford a convenient opportunity for what may be termed stock-taking in some branch of science which has especially attracted the attention of the author; for a brief re- view of past progress; for a glance forward over the rich fields which still await exploration. We may compare ourselves to pioneers in a land as yet imperfectly known, the resources of which are only beginning to be developed. Taking our stand upon some vantage-ground at the border of the clearings, we glance forward over plains as yet untrodden, over forests as yet untracked, to consider in what directions and by what methods of investigation new lands can be won through peaceful conquest, new treasures added to the world’s intellectual wealth. I purpose, then, on the present occasion to offer to you a few remarks upon a branch of geological investigation which appears to me full of promise for future workers. The keynote of my address might be conveyed in the following sentence : “The application of microscopic analysis to discovering the physical geography of ‘bygone ages.’ The ultimate aim of geological researches is obtaining answers, in the widest and fullest sense, to these two problems in the history of our globe— the evolution of life upon it, and the evolution of its physical features. In the former a host of labourers, before and since the epoch of Darwin’s great book, have been employed in collecting and co-ordinating facts, and in framing hypotheses by scientific induction. In the latter the workers are fewer, but the results obtained are neither small nor unhopeful. In the past generation, men like Godwin-Austen pointed out the principles of work and gathered no small harvest, but in the present the application of the microscope to the investigation of rock structure has facilitated research by furnishing us with an instrument of precision; this, by disclosing to us the more minute mineral composition and structural peculiarities of rocks, -enables us to recognise fragments, and sometimes even to determine the source of the smaller constituents in a composite clastic rock. The microscope, in short, enables us to declare an identity where formerly only a likeness could be asserted, to augment largely in all cases the probabilities for or against a particular hypo- thesis, and to substitute in many a demonstration for a conjecture. 602 REPORT—1886. Once for all, I ask you to bear in mind that this address is mainly a recital of other men’s work, so that I shall not need to interrupt its continuity by remarks. as to the original observers. The subject is, indeed, one to which I have paid some attention, but I can only call myself a humble follower of such men as God- win-Austen, ‘the physical geographer of bygone periods,’ and Sorby, who was the first to apply the microscope to similar problems, and to whom in this class of in- vestigation we may apply the well-known saying, Nihil tetigit quod non ornavit. With the deepest gratitude also I acknowledge the loan or the gift of specimens from Drs. Hicks and Callaway, from Messrs. Howard Fox, Somervail, Shipman, Gresley, Houghton, Marr, Teall, and J. A. Phillips, from Professors Lapworth and Judd. Through their liberality I have had the opportunity of examining for my-- self the greater part of the materials which have already been described in the principal geological periodicals, and of adding many new slides to my own collection. The nature of the materials of grits and sandstones has been so admirably treated by Dr. Sorby in his presidential address to the Geological Society for 1881 that I may pass briefly over this part of the subject. I will, however, add a few details in the hope of placing more clearly before you the data of the problems which are presented to us. In order to exemplify the size of the fragments with which we have to deal, I have made rough estimates of the diameters of the con-- stituent grains in a series of quartzose rocks. Sometimes there is much variability,. but very commonly the majority of the grains are tolerably uniform, both in size and shape. Ina slide from the Lickey quartzite, exposed in the railway cutting at Frankley Beeches, grains, often well rolled, ranging from ‘02’ to ‘03’ are very common. Ina specimen of Hartshill quartzite, they range from ‘01’ to ‘03’, but the most common size is a little under '025’”. In a quartzite from west of Rush-- ton (Wrekin) a good many grains range from ‘03’ to ‘05’. In two specimens of quartzite (white and pale grey) from near Loch Maree, the grains commonly vary a little on either side of ‘02’, while in a specimen of the ‘fucoidal quartzite ” (mouth of Glen Logan) much greater variety is exhibited, a good deal of the material being about ‘01’ in diameter, but with many scattered grains up to ‘03’. The grains in a pale grey quartzite, from the Bunter beds at the north side of Can= nock Chase; range from about ‘01’ to 015”, and are very uniform. In a liver- coloured quartzite from the same locality they are about as long, but narrower and sharply angular in form. These will serve as examples of what we may call an average, moderately fine grit or sandstone. It is my impression that in a very large number of ordinary sandstones most of the grains range from about one to three hundredths of an inch. In rocks, however, to which most persons would apply the epithet ‘rather coarse-grained,’ fragments of a tenth of an inch or more in diameter are common. It is extremely difficult to give, in general terms, an estimate of the size of the: crystalline constituents of ordinary granites, and the more coarsely crystalline gneisses. But speaking of those which enter into the composition of the ground mass, I should say that the individual quartz grains do not often exceed ‘03’, and’ are very frequently between this and :02’. In the finer-grained granites and more- distinctly banded gneisses, and their associated quartziterous schists, about ‘01” is a common size, while in the finer schists (believed by many geologists to be later in: date than the aforesaid) they range from :002’7 downwards, and do not generally exceed ‘001’. Felspar crystals, where they occur, probably do not differ very materially in area from the quartz, though they are often, as might be expected,. rather longer and narrower; mica crystals, cut transversely, are often longer and' usually much narrower. Of other constituents, as being either rarer or more liable- to change, I will not speak in detail. The individual quartz grains, in the compact: and glassy varieties of. the more acid igneous rocks, are about the same size as- those in an ordinary granite. : Space does not permit me to enter upon the methods of distinguishing between: the materials furnished by the different varieties of crystalline schists, gneisses, and igneous rocks of similar chemical composition. For the most important of these I must refer you to Dr. Sorby’s address, but I may add that there are others which: TRANSACTIONS OF SECTION C. 603- it would be almost impossible to describe in words, as they can only be learnt by long-continued work and varied experience. I do not pretend to say that in the case of a grit composed of fragments of about °02” diameter we can succeed in identifying the parent rock of each individual, but I believe we can attain to a reasonable certainty as to whether any large number of its constituents have been furnished by granitoid rocks, by banded gneisses and schists, by fine-grained schists or certain phyllites, by older grits or argillites, or by lavas and scoria. There seem to be certain minute differences between the felspars from a granitoid rock and from a porphyritic lava, and more markedly between the quartz grains from the two rocks. The latter can generally be distinguished from the polysynthetic grains furnished by certain schists or veins, and these not seldom one from another. Obviously the larger the fragments the less, ceteris paribus, the difficulty in their identification. When they exceed one-tenth of an inch the risk of important error is, I believe, to a practised observer comparatively small. Obviously, also, the shape of the grains leads to certain inferences as to the dis- tance which they have travelled from their original source, and as to the means of transport, but into the details of this I must forbear to enter. I will merely remind you that small angular fragments of quartz are so slowly rounded, when trans- ported by running water, that, if well-rounded grains appear in large numbers in a sandstone, it seems reasonable to suppose that these are, in the main, wind- drifted materials. Thus every rock in which the constituent particles admit of recognition and of identification may be made to bear its part in the work of deciphering the past history of the globe. Where the constituents have been derived from other rocks we obtain some clue to the nature of the earth’s crust at that epoch; where the locality whence a fragment was broken can be discovered, the nature, strength, and direction of the agents of transport can be inferred. Some idea as to the structure and surface contour of the earth in that district, and at that time, can be formed, and thus the petrologist, by patient and cautious induction, may, in process of time, build up from these scattered fragments the long-vanished features of the pre- historic earth, with a certainty hardly less than that of the paleontologist, when he bids the dry bones live, and repeoples land and sea with long-vanished races. The latter study is in vigorous maturity, the former is still in its infancy ; so much wider then is the field, so much more fascinating, to many minds, is the investiga- tion. There are many districts which are without fruit for the paleeontologist— there are few indeed which, to the petrologist, do not offer some hope of reward. The field of research is so wide that not one nor few men can gather all its fruits. It needs many workers, and it is in the hope of enlisting more that I have ventured to bring the subject before you to-day. Materials of the coarser fragmental rocks of Great Britain.’ I proceed now to give a brief epitome of the constitution, so far as I know it, of our British grits, sandstones, breccias, and conglomerates. I shall exclude, as involving too many collateral issues, the Post-Pliocene beds, and dwell more on the earlier than on the later deposits, because the latter obviously may be derived from the former by denudation, so that it becomes the more difficult to conjecture the immediate source of the constituent particles. Further, in order to avoid con- troversy on certain questions of classification, or for brevity, I shall occasionally group together geological formations which I think separable. It may be convenient, however, to call your attention to the localities at which, at the present day, granitoid rocks (many of which may be of igneous origin, but are of very ancient date), gneisses, and crystalline schists are exposed in Great Britain, as well as those where considerable masses of igneous rock, of age not later than Mesozoic, occur. The former constitute a large part of the north-western and central highlands of Scotland and of the islands off its west coast; they are ex- 1 I have been obliged to exclude those of Ireland, asI have so little material from that country, and for want of space have not dealt fully with those of Scotland. 604 REPORT—1886. posed in Anglesey and in the west and the north of Carnarvonshire ; they form the greater part of the Malvern Chain, and crop out at the Wrekin; they occur on the south coast, at the Lizard, and in the district about Start Point and Bolt Head ; they rise above the sea at the Eddystone. It is probable that these last are the relics of a great mass of crystalline rock, which may have extended over the Channel Isles to Brittany ; also, that we may link with the massif of the Scotch highlands the crystalline rocks of Western Ireland on the one hand, and of Scan- dinavia on the other. Among the indubitably igneous rocks we have granite, or rocks nearly allied to it, in Scotland, in the Lake district, in Leicestershire, and in Devon and Cornwall. Felstones, old lavas, and tuffs of a more or less acid type oceur in Southern Scotland, to some amount also in the Highlands, in the Lake district, and in various localities of rather limited extent in West-central England, as well as in the south-west region just mentioned, while in Wales we have, in the northern half, distinct evidence of three great epochs of voleanic outburst, viz.,in the Bala, in the Arenig, and anterior to the Cambrian! grits and slates. In South Wales there were great eruptions at the last-named epoch and in Ordovician times. I have passed over sundry smaller outbreaks and all the more basic rocks as less immediately connected with my present purpose. It is, I suppose, needless to observe that a coarsely crystalline rock, whether igneous or of metamorphic origin, must be considerably older than one in which its fragments occur. Cambrian and later Pre-Cambrian.—That the majority at least of the gneisses and crystalline schists in Britain are much older than the Cambrian period will now, I think, hardly be disputed by any who have studied the subject seriously and without prejudice. There are, however, later than these, numerous deposits, frequently of volcanic origin, whose relation to strata indubitably of Cambrian age is still a matter of some dispute. Therefore, in order to avoid losing time over dis- cussions as to the precise position of certain of these deposits, or the particular bed which in some districts should be adopted as the base of the Cambrian, I will asso- ciate for my present purpose all the strata which, if not Cambrian, are somewhat older. The latter, however, exhibit only micro-mineralogical changes, and of their origin, voleanic or clastic of some kind, there can be no reasonable doubt ; so that the difference in age does not appear to be enormous; that is to say, I include with the Cambrian the Pebidian of some recent authors. The utility of microscopic research has nowhere been better exemplified than in the case of the oldest rocks of St. David’s. Some authors have supposed that the base of the Cambrian series in this district has been ‘ translated ’ beyond recognition, others that it has been thrust out of sight by the intrusion of granitic rock. But low down in the series, beneath the earliest beds that have as yet furnished fossils to British paleontologists, there is a weli-marked and widespread conglomerate; under- lying this, with apparent unconformity,comes a series of beds very different in aspect, chiefly volcanic, and beneath this a granitoid rock. The conglomerate, in places, even without microscopic examination, proves the existence, though probably at some distance, of more ancient rock, as it is full of pebbles of vein-quartz and quartzite ; but in other parts it is crowded with pebbles closely resembling the fel- stones in the underlying volcanic group, and in some parts becomes a regular arkose, made up almost wholly of quartz and felspar, closely resembling those minerals in the granitoid rock, of which also small rounded pebbles occasionally oceur. One or two fragments of a quartzose mica-schist, which is not known to occur 7m situ in the district, have also been found. It is therefore evident that not only is the volcanic series somewhat, and the granitoid rock considerably, older than the con- _glomerate, but also that an important series of rocks, some of which were thoroughiy metamorphic, was exposed in the district when the conglomerate was formed. I have very little doubt that a study of the finer-grained sedimentary Cambrian beds overlying the conglomerate will corroborate, were it needed, the conclusion which the latter justifies. Passing on to North Wales the coarser beds in the Harlech } IT take the base of the Arenig as the commencement of the next formation, the Ordovician, which thus represents one phase of the Lower Silurian in the variable nomenclature of the Geological Survey. TRANSACTIONS OF SECTION C. 605 axis, so far as they have been examined, are found to be full of fragmental quartz and felspar, which is undoubtedly derived from a granitoid rock ; some beds being made up of little else. No rock of this character, so far as I am aware, is exposed in this part of Wales, but a ridge of granitoid rock extends from the town of Car- narvon to the neighbourhood of Port Dinorwig. Through this, apparently, the reat felstone masses which occupy considerable tracts on the northern margin of the hills between Carnarvon Bay and the valley of the Ogwen have been erupted, and over this comes a series of grits, slates and conglomeratic or agzlomeratic beds, overlain ultimately by the basal conglomerate of the undoubted Cambrian series. It was formerly maintained that these felstones were only lower beds of the Cam- brian metamorphosed—practically fused by some ‘metapeptic’ process. This notion, however, was quickly dispelled by microscopic examination. The overlying conglomerate is often crowded with pebbles, identical in all important respects with the felstone itself, which also presents many characteristics of a lava flow as opposed to an intrusive mass, and is no doubt an ancient rhyolite now devitrified. There is some difference of opinion among the geologists who have worked in this district as to the exact correlation of various gritty, conglomeratic or agglomeratic beds which succeed the felstone, as is only natural where disturbances are many, and continuous outcrops generally few. But all agree on the existence of a series, into which volcanic materials enter largely, between the above-named basal Cam- brian conglomerate and the felstone. In this, then, and in the basal conglomerate we have again and again more or less rounded fragments of old rhyolitic lavas. We have numerous and varied Japilli, probably of like chemical composition. We have grits which are largely composed of quartz and felspar, resembling that in the granitoid rock, together with fine-grained quartzose schists and bits of rhyolite, all mingled together. We have also occasionally, as in the Cambrian conglomerate near Llyn-Padarn, pebbles of the granitoid rock. Further, the basal conglomerate, as near Moel Tryfaen, is sometimes crowded with fragments of gritty argillites. Fine-grained schists, as will be noted, seem to be rare in this district, but, as such rocks occur 7m situ in the Lleyn peninsula, they will probably be discovered more abundantly when the Cambrian conglomerate is examined further in that direction. Fine-grained micaceous, chloritic, and other schists occupy a considerable portion of Anglesey, and in the neighbourhood of Ty Croes there is an important outcro} of granitoid rock. The former were once regarded as metamorphosed Cambrian, the latter as granite which aided in the metamorphism at the end of the Ordovician period. In Anglesey the earlier Paleozoic rocks are not generally rich in fossils, so that it is sometimes difficult to settle their precise position. The oldest beds which have been thus identified have been placed in the Cambrian (Tremadoc), but some experts have doubted whether quite so low a position can be assigned to them. Hence the exact age of the oldest Paleozoic beds in this island is uncertain, and whether the basal conglomerates near Ty Croes are of the same age as those in Carnarvonshire. This, however, is certain, that some of the Anglesey grits above the basal conglomerate are largely made up of quartz and felspar derived from a granitoid rock. Others include numerous fragments of very fine-grained schists, like those so abundant in the island, and the conglomerate contains pebbles some- times full two inches in diameter, absolutely identical with the rocks in the adjacent granitoid ridge (the foliated structure distinctive of some parts of it having been even then assumed), together with various metamorphic rocks, some green schistose slaty rocks, and some reddish slates. The last two were, I doubt not, cleaved be- fore they became fragments ; probably these were derived from the hypometamor- phic series, which Dr. Callaway has described, and which also contains pebbles of the granitoid rocks. Fragments of the characteristic fine-grained schists are, so far as I at present Imow, less common among the Anglesey grits and conglo- merates than one would expect, perhaps owing to their comparative destructi- bility ; but I have found them occasionally and suspected their presence more often. Hence there can be no doubt that older crystalline rocks have very largely con- tributed to the formation of at least the coarser members of the lower Palzozoics of Anglesey. 606 REPORT—1886. Passing now to Central England we come to regions which may be regarded as almost the exclusive property of your local geologists. The Hollybush sandstone on the flanks of the Malvern is, no doubt, largely composed of the finer débris of the older rocks of that chain, but the Malvern hills are only an unburied fragment of a vastly larger area of crystalline Archzean rock. This is just indicated some seven miles farther north in the Abberley hills. It crops up at either end of the Wrekin, and for a little space near Rushton, but in the later fragmental rocks of the district we have abundant proofs of its existence. The central part of the Wrekin is composed of volcanic rocks, rhyolites of varied kinds, with agglomerates; these were once regarded by our highest authorities as greenstones intrusive in beds of Ordovician age, but Mr. 8. Allport has taught us their true nature, and Dr. Calla- way has proved their far greater antiquity. Similar rocks are to be found elsewhere in the neighbourhood of the Wrekin, and in the district farther west. We cannot affix a precise date to the volcanic outbursts of the Wrekin, but we can prove that they are not newer than the quartzite which fringes the hill, as it contains fragments of the perlitic and other glassy rocks of the apparently underlying series. This quartzite is certainly much older than the newer part of the Cambrian, and pebbles of rhyolites, resembling those of the Wrekin, occur in the indubitable Cambrian beds farther west. or instance, a grit at Haughmond Hill is quite full of frag- ments of voleanic rock, many of them scoriaceous ; another suggests the derivation of some of its materials from a mica-schist, while, according to Dr. Callaway, the con- glomerates and grits of the Longmynds (which form the main part of the mass) are largely derived from older rocks, the former being crowded with pebbles of purple rhyolite, quartz, felspar, mica, and occasional bits of mica-schist. A most interest- ing conglomerate, apparently older than the quartzite, occurs at Charlton Hill. This contains more or less rolled fragments of grits, quartzites, and argillites, look- ing in several cases as if they had undergone, before being broken off, the usual micro-mineralogical changes. It contains also fragments of rhyolite and many of coarse granitoid or gneissoid rocks of Malvernian type, besides numerous grains of quartz and felspar of a like character. Finer-grained gneissoid rocks and schists, micaceous, hornblendic or chloritic, are present in fair amount. The last bear some resemblance to the Rushton rocks, and remind me strongly of rocks which occur in the Highlands and in the Alps, apparently not in the lowest part of the Archean series. Some also resemble the Anglesey schists. The quartzite itself is largely made up of grains of quartz which appear to me to have been derived from old granitoid rocks. Occasional grains, however, suggest, by their composite struc- ture, derivation from a quartzose rock of finer texture, and, as already said, bits of the Wrekin rhyolite sometimes occur. The same is true of the Lickey quartzite, in regard to all three constituents, in which an occasional grain of microcline, very characteristic of old granitoid rocks, has been observed. ‘The quartz-crains in this and in the former rock are occasionally very much rounded. The Lickey quartzite has lately been shown by Professor Lapworth to overlie rhyolitic rocks, and it is much older than the lowest Silurian. Not improbably it is of the same age, and was once connected with that of the Wrekin district. The Hartshill quartzite, near Nuneaton, has a similar composition, is below Cambrian, and overlies some rhyolitic rocks, Thus these insulated areas prove the existence of an old fragmental series, which is largely composed of materials derived from pre-existing and much more ancient Archean rocks. It is difficult to assign a date to the unfossiliferous rocks forming the rugged hills of Charnwood Forest, but, as they have been affected by very ancient earth-movements, and there is nowhere any valid evidence of volcanic activity in the true Cambrians, they may be assigned with most pro- bability to the antecedent epoch, which seems to have been one of great disturbance. Microscopic examination has shown that materials of volcanic origin enter largely into the composition of these Charnwood rocks, even the most finely grained ; but besides occasional fragments of slaty rock in the breccias, for which a high antiquity cannot be asserted, we find some pebbles of vein-quartz and two or three beds of quartzite. The grains in these appear to have been derived from old granitoid rocks, and not from the porphyritic rhyolites of the district. In one case, at the Brande, they are most conspicuously rolled, and this has happened, though less TRANSACTIONS OF SECTION C. 607 uniformly, in a grit from near the ruins, Bradgate, which also contains grains of com- pound structure. In conclusion, 1 must briefly notice the so-called Torridon sand- stone of North-western Scotland, which is in many respects invaluable to the student. That it is not later than the base of the Ordovician is indisputable ; that it is under- lain by and derived from a mass of Archzean rocks, gneisses, more or less granitoid, with occasional schists, is universally admitted. Its coarser basement beds are crowded with fragments of the underlying gneisses and schists, and since the epoch of their formation no important change has taken place in either the one or the other. The finer beds, though other materials occasionally occur, are largely, sometimes almost exclusively, composed of grains of quartz and of felspar identical in every respect with those in the underlying series. It may be a fact of some significance, for it agrees with what I have elsewhere noticed in very old fragmental rocks, that the felspar appears to have been broken off from the parent rock while still unde- composed, and in many cases is even now remarkably well preserved. It would seem, therefore, as if the denudation of the granitoid rock had been accomplished without material decomposition of its felspar, but I must not allow myself to digress into speculations on this interesting and suggestive fact. While referring to this district I may mention the quartzites, though, strictly speaking, they are Ordovician in age. These in some cases consist all but exclusively of quartz grains derived from the Archzean series, which, however, are generally smaller than those in the Torridon ; it would seem as if the felspar of the parent rock had either decomposed em situ, or had been broken up in consequence of the longer distance from the source of supply. This quartzite is sometimes of singular purity, contain- ing little or no earthy material, and only rarely a flake of mica or a grain of felspar, tourmaline or epidote (?). Ordovician-Silurian.—In regard to the earlier of these formations I am better acquainted with the volcanic than with the non-volcanic fragmental beds. Still, so far as I have seen, we find among the latter frequent indications of a supply of materials from regions of crystalline as well as of ordinary sedimentary rocks. The quartzite of the Stiper Stones (possibly earlier than the Arenig) appears to have derived most of its grains from granitoid rocks, and probably the same is true of many of the coarser beds in the Caradoc group of Shropshire and Eastern Wales. The Garth grit of Portmadoc appears to have derived much of its quartz from a like source as the Stiper Stones, but it also contains bits of a fine grained quartzose schist and of older clastic rocks. A grit from the Borrowdale series of Chapel-le- dale contains, in addition, bits of old andesite and probably diabase, with fragments of arather granitoid gneiss and quartzose schists. Fragments of crystalline rock, both small and large, abound in the Upper Llandovery beds at Howler’s Heath, at Ankerdine Hill, in the Abberley district, on the west flank of the Malverns, and at May Hill, thus indicating that early in Silurian times far greater outcrops of crystalline rock existed than are now visible west of the Severn. Mr. W. Keeping? calls attention to the abundance of fragments of quartz, felspar, and mica in the * greywackes’ of the Aberystwith district, which give the rock sometimes quite a granitoid appearance, and adds that, in his‘opinion,? ‘the abundance of felspar crystals, so general in the Silurian rocks (Upper Silurian of North Wales, South Wales, and the Lake district), points to the neighbouring presence of a vast mass of early, perhaps primeval, igneous rocks as the great source of sediment supply in Silurian times.’ What I have seen of the Denbigh grit of North Wales and of the Coniston beds of the Lake district confirms this conclusion. It is true that some of the material may have been supplied by Ordovician volcanic rocks, and that the quartz grains in the specimens which I have examined are not large. But we must remember that the latter can hardly have been furnished by the lavas of the Lake district, and those of North Wales, though richer in silica, do not, so far as I know, generally contain large quartzes. These, indeed, may have been derived from the denudation of Cambrian rocks, but I should doubt the sufficiency of such an ex- planation. In one specimen, a Denbigh grit from Pen-y-glog, near Corwen, there occurs, besides one of smaller size, a fragment about ‘1’ in diameter, exhibiting a 1 Quar. Journ. Geol. Soe. vol, xxxvii. p. 149, &c.’ 2 Ibid. p. 150. 608 REPORT—1886. micrographic arrangement of quartz and felspar. In Cornwall, among beds which are almost certainly Ordovician or Silurian, we find similar evidence of derivation from much more ancient rocks. The conglomerates of the Meneage district con-. tain, in addition to quartzites, greywackes, and other old sedimentary beds, abundant fraoments of a moderately coarse-grained granitoid rock, and occasionally a horn- blendic rock similar to the well-known Lizard schist. A series of specimens which [ have examined microscopically shows, in addition to compact igneous rocks, apparently volcanic, quartz grains probably derived from granitoid rock, various fine-grained schists and schistose argillites or phyllites, quartzites, grits, and other older clastic rocks. One fragment of schist contains little eyes of felspar, and in general structure reminds me of some in the so-called ‘ Upper Gneiss’ series of N.W. Scotland. Another, a fine-grained mica-schist or a phyllite, exhibits a cleavage transverse to the rumpled foliation. A rich harvest probably awaits the explorer in the ‘ greywackes’ of the southern uplands of Scotland. A ‘Lower Silurian’ conglomerate from Kingside, Peeblesshire, contains numerous fragments of igneous rocks, probably of volcanic origin, and bits of granitoid rock, with some which are either very old quartzites or perhaps vein-quartz. These have been crushed and re-cemented before being detached from the parent rock. The basement conglomerate of the Craig Head limestone group (Llandeilo-Bala) is full of rounded fragments of volcanic rocks. These, as in the last-named case, exhibit considerable variation ; the majority, how- ever, are probably andesites, and perhaps in one or two cases even basalts. A Middle Llandovery conglomerate from near Girvan is largely made up of frag- ments which appear to have been derived from very ancient quartzose rocks. The greywacke of rather later age from near Heriot, Edinburghshire, contains, with numerous volcanic fragments, and a little argillite, a few bits of fine-grained quartz- schist, together with grains of quartz and felspar, suggestive of derivation from a more coarsely crystalline rock. Old Red Sandstone and Devonian.—It is, I believe, indisputable that when the Old Red Sandstone of Scotland was formed a great period of mountain-making had ended and one of mountain-sculpture was far advanced. The conglomerates are often full of fragments of the crystalline rocks of the Highlands, and no doubt the sandstones derived their quartz-grains from the same source. In the southern half of the country, however, as is well known, volcanic materials, more or less contemporaneous, play an important part. I have not been able to examine closely the Old Red Sandstones of England and Wales, but their frequent near resemblance to the sandstones of Scotland suggests a similar derivation. True, the materials may have been sifted from older clastic rocks, but there is nothing specially to suggest this, and the abundant pebbles of vein-quartz, which I have seen in one or two localities, seem rather more fayourable to the other hypothesis. I have only examined microscopically a very few specimens of Devonian grit, all from the south side of the county. These certainly seem to have derived their materials, in part at least, from crystalline rocks, both granitoid and schists of finer grain ; one specimen also apparently containing some bits of hypometamorphie rock. Carboniferous.—In Scotland some of the basement beds of this series so closely resemble the Old Red Sandstone that no further description is needed, and the same remark may be made of the very few overlying sandstones which I have carefully examined. In the North of England the basement conglomerates, so far as I have seen them, are made up of earlier Palzozoic rocks, but for many of the great masses of sandstone which occur in the series a source of supply is not so easily found. Dr. Sorby, who has made a special study of the Millstone grit of South Yorkshire, tells us that it is formed of grains of quartz and felspar, apparently derived from a granite, and contains pebbles, sometimes an inch or so in diameter, of vein-quartz, of hard grits, of an almost black quartz-rock or quartz-schist, and of a non-micaceous granite. He also notes one fragment of a greenstone, and another either of a fine-grained mica-schist or of a clay-slate. The granite, he states, more resembled those of Scandinavia than any one now visible in Britain, and the bedding indicated a supply of materials from the north-east. In the Millstone grit near Sheffield he says that the grains appear to be but little worn, as if they TRANSACTIONS OF SECTION C. 609 had not been drifted from far. A few also appear to have been derived from schists. From what I have myself seen I anticipate that Dr. Sorby’s conclusions may be extended to most of the other coarser Carboniferous clastic beds of Northern England, except that, perhaps, as was inferred by Professor Hull, another impor- tant, if not the principal, source of supply must be sought on the north-west. The materials of the basement conglomerates and grits in North Wales appear to be either Paleozoic rock or vein-quartz and an impure jasper; but a microscopic study of carefully selected specimens, especially from Anglesey, might produce interesting results, In Central England, as the Old Red Sandstone is commonly absent, and, if present, must have been speedily buried, we should naturally look farther afield for the materials of the Coal Measure sandstones and Millstone grit, where it occurs. But probably we shall be right in including this, as indicated by Professor Hull, with the northern district. He also points out that in the south- western part of England and in South Wales there is good evidence that the materials -have been brought by currents from the west. I have only examined one specimen from this region, but it has proved very interesting. Itis from a Carboniferous grit near Clevedon, in Somersetshire. About one-third of the rock consists of quartz erains which I should suppose derived from schists or gneisses of moderate coarse- ness; quite another third of fragments of a very fine-grained micaceous schist, about ‘03’ long. It is possible that these may be phyllites, but I think it far more probable that they are true schists. They are very like some of the more minutely crystalline schists of Anglesey, and it is evident in some cases that the rock had been corrugated subsequent to foliation. This grit also contains a few bits of felspar and flakes of mica. I must not forget to mention some curious boulders which have been discovered occasionally in actual coal-seams. Through the kindness of Mr. Radcliffe I have been able to examine some specimens found’ at Dukinfield Colliery. They are hard quartzose grits and quartzites, bearing a general resem- blance to sundry of the earlier Paleozoic rocks. One of the latter is as compact and clean-looking as the well-known quartzite of the north-western Highlands. Besides quartz, and perhaps a little felspar, it contains a small quantity of iron- oxide (?), two or three flakes of white mica, a grain or two of tourmaline, and of a mineral resembling an impure epidote. A similar quartzite has been found by Mr. W.S. Gresley in a coal-seam in Leicestershire, and I have described another from the ‘thirteenth coal’ at the Cannock Chase Colliery. In each of these quartzites the two minerals last named may also be detected. l Before quitting the Carboniferous series I must call attention to some interest- ing grits which during the last few years have been struck in deep borings. In the London district a red sandstone, in some places conglomeratic, has been found underlying sundry members of the Mesozoic series. Some have thought this of Triassic age, but inasmuch as it is very doubtful, as we shall presently see, whether the coarser beds of the Triassic formations extended so far to the east, and the dip of the red beds in the well at Richmond agrees better with that of the Paleozoic rocks in other parts of the buried ridge, I think these sandstones more probably older than any part of the Mesozoic series, perhaps not very far away from the base of the Carboniferous. In the boring at Gayton, in Northamptonshire, Lower Car- boniferous rocks were succeeded by reddish grits and sandstones. The finer beds much resembled the ordinary Old Red Sandstone, and, like it, sugzested a deriva- tion from fairly coarse-grained crystalline rocks. But of the origin of one rock, a quartz-felspar grit, there can be little doubt. I may briefly describe it as very like the Torridon sandstone of Scotland, except that the cement is calcareous. I do not, indeed, claim for it a like antiquity, for I think it far more probably about the age of the lowest part of the Carboniferous series; but it, too, must have been derived from granitoid rocks. While some of the grains are fairly well rounded, others, especially of felspar, as in the Millstone grit of South Yorkshire, do not seem to have travelled very far. Permian.—The sandstones of the northern area belonging to this formation do not, as far as I have been able to ascertain, afford us much information. Quartz grains, of course, abound, but as they are rather small, it is not possible to be sure whether they have been primarily derived from a granitoid rock or a schist. The 1886. RR 610 REPORT—1886. former, however, appears to me the more probable source. They also contain fragments of felspar still recognisable, flakes of mica, and possibly a little schorl. The frequent occurrence of crystalline quartz as a secondary formation in these sandstones is a point of much interest, but has no relation to my present inquiry. The breccias near Appleby, Kirkby Stephen, &c., which I have not seen, indicate that at this time, not distant, masses of Carboniferous limestone, and of earlier Paleozoic rocks, were undergoing denudation ; but it appears to me improbable that the finer materials of the sandstones were furnished by any rocks in the vicinity. The Permians of the central area offer a rich field for future work. For the materials of the sandy beds I should conjecture a distant source, but for the pebbles in the conglomerates, and the fragments in the breccias, we need not travel very far afield. The Lower Carboniferous Measures contributed limestone and chert, the former being especially abundant in the conglomerates, but the ‘ vein-quartz, jasper, slates, and hornstone,’ mentioned by some observers, indicate that yet earlier rocks furnished their contingent, while of the igneous materials I will speak directly. I shall pass very briefly over the breccias, so well displayed, for instance, on the Clent and Lickey hills, at no great distance from this town, because I trust we shall have presented to us, in the course of this meeting, a sample of the rich harvest which is awaiting explorers. Earlier investigators looked towards Wales for the origin of these fragments; we shall, I believe, learn that the majority are more probably derived from rocks which, though now almost hid from view, exist at no great distance. Some of the more compact traps may have come from the old rhyolites, which, by the labours of your geologists, have been detected zm stu beneath the Lickey quartzite, while we may venture to refer the ‘red syenite’ and ‘red granite’ to outcrops of crystalline rocks of Malvernian age. These breccias have been regarded as proving the exist- ence of glaciers in the Lower Permian age, It is, of course, possible that floating ice has been among the agents of transport, but after carefully examining the specimens in the museum of the Geological Survey, on which glacial striz are asserted to occur, J am of opinion that the marks are due to subsequent earth- movements. On only one specimen did I recognise glacial striation, and this pebble is so different from the rest that I think it must have come from drift, and not from the Permian beds. No less interesting are the Permian breccias of Leicestershire. These have attracted the attention of an indefatigable local geologist, Mr. W. 8S. Gresley, and to his kindness I am indebted for the opportunity of examining both rock specimens and slices. As might be expected, fragments, which I have no hesitation in referring to the Charnwood series, are not wanting, though hitherto they have not occurred in any abundance ; but perhaps the most interesting member is a tolerably hard conglomerate, containing rather abundantly pebbles of a speckled grit and of a compact ‘trap.’ Microscopic examination of this conglomerate, which varies from a fairly coarse puddingstone to a grit, shows that the above-named speckled grit is composed of small and rather angular fragments of quartz, associated with grains of brownish and greenish material, which may be in some cases decomposed bits of a rather basic lava, in others possibly a glauconite of uncertain origin. But the ‘trap’ pebbles are yet more interesting. These are.the more numerous, and are commonly well rolled. They probably belong, roughly speaking, to one species, but exhibit many varieties. In a single slide I have seen at least six, perfectly distinct. Some are indubitably scoriaceous, others full of microliths of a plagioclastic felspar, others almost black with opacite, others mottled brown devitrified glasses, more or less fluidal in structure. Probably they belong to the andesite group, with a silica percentage not very far away from sixty. In none have I observed any signs of crushing or cleavage, so that I cannot refer them to the Charnwood series, but conjecture that they are relics of volcanoes later in age than the great earth movements which affected that series, though I cannot connect them with the more basic post-carboniferous outbreaks of which we have indica- tions at Whitwick and elsewhere. Quartz grains also occur, and some of these exhibit a rather peculiar ‘network’ of cracks which is characteristic of this mineral TRANSACTIONS OF SECTION C. 611 in the rocks of Peldar Tor, Sharpley, &c., and one such grain is attached to a fragment of minutely devitrified rock. Hence, as shown by larger fragments, the ‘Charnwood series has contributed to the materials of this conglomerate, but the more abundant appear to have been derived from volcanic vents, the locality of which is at present undiscovered. Trias—The Bunter beds and the lower part of the Keuper consist of more or ‘less coarse materials, while in the remainder of the latter such deposits are rare and local. Hence it is evident that after the deposition of the Keuper sandstones a very different set of physical conditions prevailed. The lower series consists of sandstones and conglomerates; these beds occur in considerable force on the -eastern side of the Pennine chain, have a great development in Lancashire and ‘Cheshire, and thin away towards the south-east, almost disappearing in eastern Leicestershire and in Warwickshire. As the Trias is followed southwards, along the valley of the Severn, the Bunter in hke way dies out, while the Keuper marls may be traced on into Somersetshire and Devon. In that region also there is a grand development of the lower and coarser members. As might be expected, there are considerable differences between the lower Triassic deposits of the northern and southern areas, so that it will be convenient to speak of them separately. The northern group, as is well known, is separable in the Midland and north-western district into the Lower Bunter sandstone, the Pebble-beds, and the Upper Bunter sandstone, over which come, more or less unconformably, the Keuper sandstones. Pebbles are either absent from, or very rare in every part of the Bunter except the pebble-bed, and are generally small and scarce in the Keuper sandstones, except in the basement breccias. It will be conyenient to make a few remarks on them before dealing with the associated sands and sandstones. The pebbles in the Bunter conglomerate are most abundant, and generally attain the largest size in the Midland district. Towards the north-west, though the conglomerate attains a thickness of more than 500 feet, pebbles are rarer and smaller, and this, I believe, is also the case in Yorkshire, though the thickness of the deposit is not so great. I -ean, however, answer for the occurrence of pebbles of fair size and in considerable abundance for some distance to the north of Retford. In the Midland district they are very frequently from about 2” to 4” in diameter, though smaller are inter- mingled and occasionally some of larger size; these attain in certain localities to a diameter of 6”, or even more. The majority, so far as I know, are well rounded. In this district many different kinds of rock are found in the con- -glomerate; the most abundant are quartzose—vein-quartz, quartzites and hard grits or sandstones. Besides these we find chert and limestone from the Car- boniferous series, various fossiliferous rocks of Silurian, Ordovician, and possibly Cambrian age, with mudstones and argillites, more or less flinty, of uncertain date. Felstones, using the term in a wide sense, are not rare, and granites or granitoid rocks sometimes occur. These, however, together with the scarce frag- ments of gneiss and schist, are usually very decomposed. A hard quartz-felspar _grit, sometimes very like a binary granite, may be found, and I have noticed a peculiar black quartzose rock of rather schistose structure. As the lithology of the Bunter conglomerate has already attracted the notice of more than one author, I shall restrict myself to a brief mention of its more salient features. The most abundant rock is a quartzite, frequently so compact as to give a rather lustrous sub-conchoidal fracture, in which the individual grains can be with difficulty distinguished. In colour it varies mostly from white to some tint of grey, but is occasionally ‘liver-coloured.’ Rather obscurely marked annelid-tubes are the only organic indications which I have observed in these quartzites, and these are very rare. Under the microscope the rock consists chiefly of quartz fragments, -of various forms in different specimens, with an occasional fragment of felspar (sometimes, I think, silicified), a flake of white mica, a grain of tourmaline, and of -an impure epidote (?). Asa rule it is easy to distinguish this quartzite from the 1 I pass by the interesting pebbles of hematite, which have received special «attention from Mr. Gresley. RE 2 612 REPORT—1886. other indurated arenaceous rocks which occur in the conglomerate, especially from those containing fossils. The above-described quartzites differ in appearance both macroscopically and microscopically from those of Hartshill, the Lickey, and the Wrekin district, but they closely resemble the most compact variety, which I have already described as occurring in boulders in coal. They have also an extraordinary likeness to quartzite pebbles in Old Red Sandstone and Lower Carboniferous conglomerates of Southern Scotland and to the quartzites of the northern and western Highlands,. already described, a liver-coloured variety of which, as I have been informed, occurs in the island of Jura. These quartzite pebbles, to my knowledge, may be traced into Lancashire on the one side of the Pennine chain and to beyond Retford on the other. The quartz-felspar grit consists mainly of quartz and felspar, obviously the débris of granitoid rock. I have found it at various localities on the northern margin of Cannock Chase and have received specimens from the Bunter beds near the Lickey and near Nottingham. The rock, macroscopically and microscopically, presents an extraordinary resemblance to the Torridon sandstone of North-west Scotland, and differs from every other rock which I have seen zm situ in any other part of Britain. The nearest approach to it is the quartz-felspar grit, already mentioned as haying been struck in the Gayton boring, Northamptonshire, but this has a calcareous cement. The felstones vary from micro-crystalline to glassy rocks more or less devitrified, some being slightly scoriaceous. They may be classitied lithologically as quartz-felsites, rhyolites (more or less devitrified), quartz~porphy- rites, porphyrites, and old andesites. Some specimens contain a considerable amount of tourmaline, and I have seen this mineral in the vein-quartz pebbles. It also occurs rather abundantly in a very hard, black quartzose grit. I have received varieties of felstone, which I have found on Cannock Chase, from the Bunter beds of the Lickey and from Nottingham. In Staffordshire pebbles of granitoid rock, gneiss, and schist are not only rare, but also generally too rotten to admit of ex- amination ; but I found, a few months since, in the conglomerate at Style Cop, near Rugeley, two pebbles of a whitish gneiss, which appeared to me to indicate a secondary cleavage-foliation, such as may be observed in many parts of the Scotch highlands. The black quartz-schist already mentioned exhibits a peculiar ‘ squeezed-out ’ structure, which ordinarily indicates that the rock has undergone great pressure. The sandy matrix and associated sandstones of the conglomerate beds, together with those of the Upper and Lower Bunter, and of the Lower Keuper, consist mainly of quartz grains, most of which appear to have been derived originally from granitoid rocks. They are often more or less angular, but at certain horizons, as described by Dr. Sorby, Mr. Phillips, Mr. G. H. Morton,! and others, well-rounded grains are so abundant as to suggest an exposure to the action of the wind. They are often stained red with iron peroxide, and mixed with more or less earthy matter. In Cheshire and Lancashire recognisable grains of felspar have been noticed by Mr. Morton and others, and probably this mineral is, in most cases, the source of the argillaceous constituents which are often intermingled with the quartz grains. Flakes also of white mica are sometimes rather common. So far as I have been able to judge, distinct grains of rolled felspar are commoner in the north-western district than in Staffordshire, where, however, mica-flakes are sometimes rather abundant. The Keuper sandstones seem to me to differ from the above only in the general absence of the red colour, and in a more even bedding, especially towards the upper part (the waterstones), where they are interbedded with the marls. The appearance of these last suggests that the currents were gradually losing strength,. and only capable of transporting the finer felspathic detritus with occasional tiny plates of mica. The lithology of the lower part of the Trias in the southern area is as yet imperfectly worked out, and a rich harvest awaits the student. My own know-. ledge of it is but superficial, so that I must pass it by with a brief notice. The 1 In an excellent paper published in the Proceedings of the Liverpool Geological Society, vol. v. p. 52. TRANSACTIONS OF SECTION C. 613 great beds of breccia, so finely exposed on the South Devon coast, are crowded with fragments, sometimes of large size; these have clearly been derived from the older rocks which are still in part exposed to the west and south-west, and probably had once a much greater extension in the latter direction. Fragments of Devonian limestone, grits, and slate, together probably with other Paleozoic rocks, earlier and later, are mingled with granites, resembling those of Cornwall and Devon, and many varieties of more compact igneous rock. The fossiliferous quartzite pebbles which occur mingled with others in the Trias at Budleigh Salterton, have been discussed by the late Dr. Davidson in an exhaustive memoir.1_ He refers the majority of the fossils obtained from them to the Lower Devonian age, but a few are Caradoc, and four occur in France in beds which are either Llandeilo or perhaps a little older. As the first two formations are represented, lithologically and paleeontologically, on the opposite side of the Channel in France, and the third is at present only known to occur in the Grés Armoricain of that country, he thinks it probable that these pebbles have been derived from rocks which are now concealed beneath the waters of the Channel. It may then, I think, be taken for granted that land to the west and south-west has supplied the materials of the Lower Trias of the southern district of England, and I may add that there is every reason to believe that outliers of the formation itself still exist beneath the sea. The so-called dolomitic conglomerates, which occur chiefly in Somersetshire, have been so fully worked out by Mr. Etheridge and Mr. Ussher as to require but a passing notice. It is evident that they differ somewhat in date, though probably all may be referred to the age of the Keuper, and that they are local breccias or con- glomerates formed around the margin of islands or on a continental coast-line during a gradual subsidence and in comparatively quiet waters. Jurassic.—Coarse detrital material is not very common in the Jurassic series. The limited Rheetic beds indicate a transition from the peculiar physical conditions of the Keuper to the marine conditions of the Lias, and the sediment in them was probably derived from the same source as the Keuper marls. Great clay beds also occur, as is well known, throughout the Jurassic series; and the sandstones, so far as I have been able to examine them, do not enable me to offer any suggestions as to their origin. Probably some of the grains were originally derived from granitoid rocks, but they may have been directly obtained from other sandstones. A grit, however, in the estuarine series of the lower oolites of Yorkshire (Mr. Philipps’s collection) looks as if it might have been partly derived from a schist, but as this is the only rock from the northern area which I have had the opportunity of minutely examining, it would be imprudent to speculate. Neocomian-Cretaceous.—I have examined very few specimens from the fresh- water Neocomians of the South of England, but, so far as I have seen, I should think it probabie that the quartz had been derived from old crystalline rocks, though perhaps not immediately. The same remark applies to the sands of the upper and marine series, which, in one instance at least, exhibit exceptionally rounded contours.” Among these, however, conglomeratic beds occur which have already attracted some attention. It is obvious that no small part of the muterials, as at Farringdon, Potton, and Upware, has been derived from fossiliferous secondary rocks of earlier date. There are also pebbles of vein-quartz and quartzite which, however, may have been obtained by the denudation of Triassic rocks. The «Lydian stone,’ which is abundant in angular or subangular fragments at Potton and Upware, is for the most part chert from the Carboniferous Limestone, or in some cases from Jurassic rocks, but a few specimens may be flinty argillites, and thus of greater antiquity. One or two pebbles of older Paleozoic rock have been found, and a hard quartz grit has occurred, containing among its grains minute acicular erystals, probably of tourmaline. Potton has furnished one or two pebbles which appear to be a devitrified pitchstone, and a large pebble of porphyritie quartz- felsite has been sent to me by Mr. Willet from Henfield (Sussex), These conglo- 1 ¢ British Fossil Brachiopoda’ (Mem. Paleont. Soc. vol. iv. p. 317). ? Professor Rupert Jones has called attention to sand-worn pebbles in the Upper ‘Tunbridge Wells sandstone of the Weald (Geol. Mag. Dec. 2, vol. v. p. 287). 614 REPORT—1 886. merates, together with others in the Upper Neocomian of England, have been so» fully described by Mr. Walter Keeping? that I need not enter into further details, though I am well aware that the subject is by no means exhausted. For a like reason I may pass briefly over the remarkable erratics found in the Cambridge greensand.* They occasionally slightly exceed a cubic foot in volume, but are generally smaller. Among them are diverse sandstones and grits, probably Paleozoic, granite, gneiss, various schists, quartzites and slates, besides greenstone,, a very coarse gabbro or hypersthenite, and a compact felstone. I think it highly probable that many of these erratics came from the north, in some cases almost certainly from Scotland, and were transported by ice, though I am not satisfied that any exhibit true glacial strie. In the South of England a boulder of old quartzose rock, perhaps a piece of a coarse quartz-vein, crushed and recemented, has been found by Mr. J. 8. Gardner in the gault, and in the chalk we have the well-known cases of the granitic rock and other boulders at Penley, near Croydon, and of coal (Wealden or Jurassic) in Kent.? Mr. Godwin-Austen describes other instances of pebbles in chalk, and I have received two or three small specimens. from Mr. W. Hill, from about the horizon of the Melbourne rock, which, however, have not yet thrown any light on the subject. Eocene.—Preyious writers have called attention to the fact that the sand of the Thanet, Oldhaven, and Bagshot beds is mainly composed of quartz. This is abundantly confirmed by my own observations. So far as I have seen, in all these- the grains are not, as a rule, conspicuously rounded. It can hardly be doubted that older sandstones or granitoid rocks lying to the west have furnished the materials of the Bagshot series, which still has so wide an extension in that direction; their lithological similarity would lead us to look towards the same quarter for the materials of the more limited Oldhayen and Thanet beds. The well-rolled flint pebbles in the Oldhaven series, and in occasional layers in the Bagshot, suggest the proximity of a shore-line of Upper Cretaceous rocks. I have had no opportunity of adding to what has been written on the lithology of the limited Pliocene deposits in England, and, as stated at the outset, have: excluded from the scope of this address all beds of later date, which have been so ably discussed by Mr. Mackintosh, Dr. Crosskey, and many other geologists. Principles of Interpretation. In attempting to interpret the facts which I have enumerated we must bear in mind the following principles :— (1) Pebbles indicate the action either of waves of the sea,‘ or of strong currents, marine or fluviatile. (2) The zone in the sea over which the manufacture of pebbles can be carried on is generally a very narrow one. It extends from the high-tide line to the depth usually of a few feet below low-water mark. It is estimated that, as a rule, there is no disturbance of shingle at a greater depth than 20 feet below the latter. It is therefore probable that a thick and very widely extended pebble bed is not the result of wave action. (8) The movement of the deeper waters of the sea asa rule is so slight that only the very finest sediment can be affected by it. Now and then great currents like the Gulf Stream, or more locally ‘ races,’ may have sufficient power to transfer pebbles and sand, but instances of this will be exceptional, and confined to rather shallow water. The larger coast currents, however, may transport mud to con- siderable distances, but in directions parallel with the main trend of the shores. (4) Except where very large rivers discharge their water into the ocean, or iz * Geol. Mag. Dec. 2, vol. vii. p. 414. * Sollas and Jukes-Browne (Q. J. G. S. vol. xxix. p. 11). * Godwin-Austen (@. J. G. S. vol. xvi. p. 327). * The waves of lakes also have some rounding effect, but this—except in the case: of very large lakes, such as Lake Superior—is not important; and such eases are, of course, not of common occurrence. TRANSACTIONS OF SECTION C. 615 some special case of (3), sediment is deposited comparatively near the shores of continents. Even in the case of very large rivers only the finer sediment is carried far from land. The Challenger soundings have shown that 150 miles is about the maximum distance from land within which any important quantity of detrital materials is deposited.1_ As a rule (so far as I can ascertain), the coarser sediments are generally deposited within a few miles of the coast. Hence this is fringed by a zone of sediment, which, after passing a maximum thickness within a short distance from the shore, gradually thins away. I doubt whether this detrital fringe is often more than 70 or 80 miles wide: probably the coarser sands do not usually extend for so much as a quarter of this distance. The inertia of the mass of the ocean water quickly arrests the flow of even the mightiest river, or reduces it to a mere superficial current. Hence the great ocean basins are regions where rock-building is carried on slowly and chiefly by organic agency. Their borders bear the burden, and the load taken off the continent is laid down on the bed of the adjacent sea. (5) Thus rain and rivers are generally more important agents of denudation and transportation than the sea, because unless the land be rising or sinking the zone over which the latter can operate is limited both vertically and horizontally. (6) The coarser materials of rock are capable of being transported by streams to considerable distances, without serious diminution of volume. Professor Daubrée has proved experimentally that astream flowing at the rate of about two miles per hour would roll angular fragments of quartz or hard granite into perfectly smooth pebbles after a transit of 25 kilometres (153 miles). During this process the frag- ments lost about four-tenths of their weight. Further transport reduced the volume of the pebbles very slowly. The loss afterwards varied from ;4, to ;4,; per kilo- metre. To reduce a pebble of 2 inches diameter to 1 inch diameter—that is, to diminish its volume by seven-eighths—would require a journey of from about 219 to 875 kilometres (approximately from 137 to 548 miles). This approximation, rough as it is, becomes still less exact as the pebbles decrease in size; the rate of diminution in volume (ce@fer’s paribus) bearing a relation to the area of the surface. Thus the smaller the pebble, the further it will travel without material diminution of size. Sand grains are even rounded with extreme slowness. According to the same author a quartz grain 4 inch in diameter requires to be transported by water action some 3,000 miles before losing its angles. On this account the presence in a sand- stone of numerous well-rounded grains is taken to indicate the action of wind, for, as is well known, blown sands are much more quickly rounded.” (7) Thus deposits of gravel and coarse sand, of considerable vertical thickness and great extension, are more likely to indicate the immediate action of a river than of a marine current. If limited in extent they may have been formed at the embouchure of a river into a lake or sea. If, however, they can be traced for long distances, they are more probably in the main sub-aerial deposits from rivers. The following examples may convey sume idea of the kind of river which would be required to transport the more important deposits of grits and stones mentioned in the first section of this address :— The old river gravels of the Sierra Nevada are ‘in some places 300 or 400 feet thick and almost homogeneous from top to bottom,’ sometimes they even obtain a thickness of 600 feet. Mr. Whitney is of opinion that the fall in these old river channels was probably from 100 to 130 feet per mile. Apparently, however, we need not invoke so large a fall as this. The total fall of the Danube is 3,600 feet, and its length 1,750 miles. From Passau to Vienna the fall is 1 in 2,200, from Vienna to Old Moldova 1 in 10,000. Yet the velocity of the current from Vienna to Basias (15 miles above Old Moldova) is ‘from 2 to 3 knots an hour,’ depending on the amount of water. This would suffice to transport pebbles of the average size of the English Bunter. Below the Iron-gates the fall is still less rapid, but sand is carried down for a very considerable distance. If then the rivers of the old ? I except floating pumice, cosmic dust, &c., as comparatively unimportant. ? See, on the subject of this paragraph, Daubrée, Géol. Hxpériment., vol. i. sec. 2, Ch. I., and J. A. Phillips, Y. J. G. S. vol. xxxvii. p. 21, &c. 616 REPORT—1886. continental land resembled the larger streams of Europe they would suffice for the transport of the materials with which we have dealt, especially if aided by coast currents after the débris had reached the sea. (8) If boulders occur in a matrix consisting of fine mud, or mainly of organic material, they must (unless they are volcanic bombs) have floated thither either attached to large seaweeds or entangled in the roots of trees, or supported by ice. If they are rather numerous and a foot or more in diameter, in a marine deposit, the last is the most probable mode of transport. A cubic yard of ice will more than suffice to float a cubic foot of average rock. Conclusion. ' The facts already mentioned, regarded in the light of the above principles, justify, in my opinion, the following inferences as to the past physical geography of our country. At the commencement of the Cambrian period great masses of Archean rock, granites, gneisses, and schists must have existed, not only on the western side of britain, but also over a considerable tract of land now covered by the sea. Detritus from this continent became an important constituent in the Cam- brian rocks, and in many cases, as at St. David’s, in Anglesey, Carnarvonshire, &c., the shore-line must have been very near at hand. With the Cambrian period commences a long-continued subsidence, so that its basement beds at different places are very probably not all of quite the same age. The land surface was from the first irregular, and it is very probable that waves of the sea were fretting away some parts, while rain and river, heat and cold, were still sculpturing others. But among the materials of the ancient land were not only granitoid rocks, gneisses, and schists, but also newer strata more distinctly of clastie origin, memorials of past denudation—quartzites and grits, phyllites and slates, not to mention others—and these, by their intimate structure, sometimes indicate that great earth-movements must have already occurred.' In many localities, perhaps as a result of these disturbances, there occurred, towards the conclusion of the Archean period, great volcanic outbursts—by which, no doubt, numerous cones were built up, and many of the materials of the so-called Pebidian Group were supplied. It is, I think, at present hardly safe to attempt to trace the exact land boundaries of the Cambrian ocean, but the enormous masses of Archean material which are entombed in the earlier Paleozoic strata of Wales and of North-west Scotland can, I think, only be explained by the proximity of a great continental land—an extension of the present Scandinavian Peninsula —which not improbably had a general slope towards the south-east, the main watershed of which may have lain some distance to the west of the Outer Hebrides.” But even over the more central parts of Britain there cannot have been deep or open ocean. We are constantly coming upon the traces of pre- Cambrian and early Cambrian land ; some of our Mid-England Archean masses, like the Malverns, appear to have risen above the water, and to have undergone denudation after the great earth-movements which ushered in the Silurian period. Prior to this, after a time of repose in the Cambrian, at more than one epoch, and in more than one place, there were great volcanic outbursts, which appear to have studded the sea with volcanic islands, and to have added to the heterogeneous materials from which the sediments were now formed. It is evident that in Silurian times the coast-line had extended southward and eastward. The coarse deposits of this age, in Wales, the Lake district, and Southern Scotland, compared with the finer mudstones and limestones of the Welsh border and of England, seem fully to bear out this assumption, which is in accordance with a well-known law of mountain-making. The Old Red Sandstone of Scotland and of Wales indicates 1 Tt is evident, for instance, that the north-west strike, and other effects of folding, had been produced in the Hebridean series of N.W. Scotland before the Torridon sandstone was deposited. . ? Possibly the comparatively rapid deepening of the Atlantic beyond the 100- fathom line may have some relation to the western outline of this primeval Atlantis. TRANSACTIONS OF SECTION C. 617 a yet further continental extension towards the south-east. A great epoch of mountain-making in the Scotch Highlands, which had perhaps been going on at ° intervals from the beginning to the close of the Silurian period, had now come to an end; the southern uplands had risen up, like a Jura to the Alps. But probably their elevation did not terminate the earth-movements, for the post-Silurian cleavage of the Lake district, and the absence of Old Red Sandstone both here and in Central England, indicate that the Paleeozoic land mass continued to extend on its south-eastern flank. The Devonian period introduces us in the greater part of ‘Great Britain to an epoch of limited and exceptional deposits, and of widely preva- lent terrestrial conditions. It seems almost certain that the Old Red Sandstones of Scotland and Wales are of fresh-water origin—the deltas of rivers, formed either in lakes or possibly in part as sub-aerial deposits. Streams of considerable volume and of some strength are indicated by the materials. In one case, the Old Red Sandstone of North-east Scotland, we may perhaps discern in the Great Glen ‘some indication of the old river-course. It is easy to ascertain the source of the materials of the Scottish Old Red Sandstones. They are as obviously the detritus of the Highland mountains—then probably a far grander and loftier chain—as the nagelflue and the molasse of Switzerland are of the Alps. At this time marine conditions prevailed in the south of England. The sea appears to have deepened towards the south, but I suspect that a region of crystalline rocks still existed at no great distance in that direction and in the west. Probably the Brito-Scandinavian Peninsula curved round to the east so as to include some part of Brittany.1. Another great epoch of subsidence now com- menced, commemorated by the formation of the Carboniferous limestone. At this I need hardly glance, as it has been so fully discussed by Professor Hull and other writers. The land sank both in the north and in the south of England. There was deep sea over Derbyshire and Southern Wales, but the ground beneath our feet probably remained above water, forming either a continental promontory or a large island. There were other well-known interruptions to the sea, which also overflowed a considerable part of Ireland and districts far to the east of England. The Scotch Highlands, however, probably remained above water, for, as is well known, the ‘Carboniferous limestone of Central Scotland overlies afresh-water formation, and is itself not wholly marine, since it contains coal, and like conditions prevailed in Northumberland. 2 Gradually, however, the sea shallowed, and terrestrial conditions returned. In the later part of the Carboniferous series we have clear indications of two, or perhaps three, important currents, almost certainly those of rivers, bringing materials, in the southern district from the west ; in the northern, from the north- west and probably the north-east. These materials may have been in part derived from older Paleozoic rocks, but the facts when carefully considered seem to indicate that there was also an extensive denudation of crystalline and not improbably Archzan rocks, unless we suppose that great areas of eruptive Paleozoic granite have now disappeared beneath the waters. At any rate, we may perhaps regard the open water between Ireland and Scotland on the one hand, and to the east of the latter country on the other, as significant of a denudation earlier than that of the sea which has in later times divided the British Isles. Another epoch of earth- movements closed—as was to be expected—the Carboniferous subsidence and deposition. We trace one line of flexures and of intense compression along a broad zone, including the south of England, from Germany to Ireland ; another less intense over the northern part of our country; the axes of the former flexure striking a little N. of W., of the latter about W.S.W. The one appears to me to indicate a thrust from a great mass of hard, more or less crystalline rock in the S., which probably led to the formation of a mountain chain extending from North- central Europe over the Channel to the southern margin of England, The latter may be explained by the presence of the above-named north-western continent. ’ Compare, as an illustration, the curving round of the Alpine chain on the western side of Italy. 618 REPORT—1886. In the Permian time terrestrial conditions probably prevailed over a large part ‘ of Britain. It is extremely difficult to ascertain the exact circumstances under: which the Permian beds of Central England were deposited, but I should think they imply a return to physical conditions not unlike those of the Old Red Sandstone,. though perhaps the marine fossils which have been found in Warwickshire may indicate that the water there had some imperfect connection with the sea. EF must not discuss the vexed question of the age of the Pennine chain, but must content myself with expressing my opinion that, at most, it can only, as yet, have very partially interrupted the continuity of the water in Northern England. The beds there appear to indicate a supply of materials from the north and north-west, as if the old rivers had not been wholly diverted by the great earth-movements which closed the Carboniferous period. Sir A. Ramsay’s view, that the water in which the dolomitic limestone was deposited was more or less cut off from the open sea, seems to me by no means improbable; in any case, it is a rather excep- tional formation, and over the greater part of Britain, probably, land sculpture continued, and deposition was on the whole local. With the Trias a new era commences; physical features had been now pro- duced, which, in all probability, endured through a considerable part of Mesozoic times. The facts which I have laid before you, regarded in the light of the general principles indicated above, compel us to look away from the immediate vicinity for the bulk of the materials, coarse and fine, of which the northern Trias is com- posed,. though neighbouring hills may have furnished occasional contributions, especially to the earlier deposits. The analogy of the Old Red Sandstone, the Calciferous Sandstone of Scotland, and the Nagelflue and Molasse of Switzerland, together with other peculiarities too well known to need repetition, make it in the highest degree probable that the Bunter beds were not deposited in the ocean.” Hence they must be either deltas formed in an-inland sea or in a lake or true fluyiatile deposits. Neither lake nor inland sea appears likely to have been sufficiently large to admit of waves or currents capable of either rounding the pebbles or trans- porting the materials. We are therefore compelled to fall back upon the action ot rivers. The sandy beds of the Bunter indicate a stream flowing from one-third to half a mile an hour, the pebbles one from two to three miles;.that is to say, the Upper and Lower Bunter sandstones would require the former rate of movement, the Pebble Beds the latter. Now, we must remember thet, in the West Central district, the Lower Trias consists of three wedge-like masses, about 100 miles in length, of which the coarser is probably the more extensive. The comparative uniformity of the deposits in each case indicates a uniformity of flow, and suggests either a large and broad stream, not liable to much variation, or one which, when flooded, quickly made a channel of its valley and deposited mainly at such season. I have the greatest difficulty in understanding how a current of the requisite velocity could be maintained by the water of a river or rivers flowing into a lake or an inland sea, or in explaining the tripartite arrangement of the beds on the hypothesis that a basin was gradually filled up from the northward by a stream which, like the Rhone at the upper end of the Lake of Geneva, gradually advanced its delta by flowing over the materials which it had previously deposited in the- basin. Hence I believe that we must regard the Bunter beds as sub-aerial deltas, analogous to the conglomerates in the Siwalik deposits of India,” and to the sandstone and nagelflue on the outer zone of the Alps, deposits in all respects very similar to the English Bunter. We may suppose, then, that rivers emerging on each side of the Pennine chain from a mountain land first formed the Lower Bunter sandstones, then, owing to increasing upheaval in the mountain district, and corre- sponding depression in the lowlands, flowed more swiftly so as to cover this deposit with the Pebble Bed, and lastly, as its former conditions returned, laid upom this the Upper sandstones. I have spoken, for the sake of clearness, as if these 1 Compare also the Bunter and Keuper in the region traversed by the German Rhine. 2 The analogy of the Indian conglomerates was suggested to me by Dr. Blanford. See Geol. Mag. Dec. 2, vol. x. p. 514. TRANSACTIONS OF SECTION C. 619 were perfectly distinct formations, but it would by no means follow that some part of the finer beds to the south-east might not be contemporaneous with a portion of the coarser beds to the north-west, as the velocity first increased, and then diminished. As | have already said, the materials of the pebbles and of the sand make it impossible to refer the main constituents to local:sources. Many of the rocks do not exist in the Midland ; there is no reason to suppose that at that time there were in this region masses of land of sufficient area and height to feed important rivers.|_ From currents of any other kind we are precluded, so that I believe we may safely turn our eyes northward and look for the ultimate source of the Triassic sandstones and conglomerates among the older rocks of the Scotch Highlands, and their extension to east and to west, though very probably the materials may have been more directly supplied from Old Red Sandstone and early Carboniferous strata, in remnants of which identical fragments may still be seen. In like way we may regard the Trias of the south of England as the detritus of at least one great river, which flowed from the west or south-west. The materials of the Keuper came from the same directions in each case, but here, I think, we have indications of deposition in an inland sea.. Breccias formed on its coasts, and sands were at first deposited in it; but presently the area of water ipcreased, and the coarser materials must have been arrested in the uplands, while the fine sediment which forms the marls may have been carried out into the salt lake and slowly settled down in its calm waters.* Its shores may have been hardly more favourable to a vigorous development of life than were its salt- saturated waters; during this period and the preceding Bunter the lowland border of the mountains, like some of the northern districts of India, may have been arid and barren regions of shifting sands. The Trias of Northern Scotland very seebabily indicates a repetition on a more restricted scale of the physical conditions of the Old Red Sandstone, but after this we observe signs of an encroachment of the Atlantic on the above-named old area of continental land. The Jurassic series is represented in Northern Scotland on both the western and the eastern coasts by marine or estuarine beds. This probably indicates important modifications in the river channels, subsidence on the west altering the slopes, reducing the length, and cutting away some of the feeding ground. Traces may still be discerned in England of the two northern rivers, but that which in Triassic: times was the larger contributor, appears in Jurassic to have been gradually enfeebled ; the other one and the south-western stream seem to have still flowed with some strength. Sands, however, now become comparatively local. Probably the coarser materials, as a rule, did not reach the sea. This appears at all times to have been comparatively shallow and enclosed by land on every side but the south-east. The recent discovery of Oxford Clay beneath the Cretaceous beds at Chatham 1 Tt may be useful to give a rough idea of the quantity of rock which must have been denuded in order to obtain materials for the Bunter beds. Suppose, for purposes of calculation, we consider the Bunter beds, which cover the district from the Cheshire coast to the Midland counties, as forming the section of a cone con- tained by two planes drawn through the axis so as to include an angle of 30 degrees. If h be the height of this axis, and 7 the radius of the base, the volume of 2 this figure is oo . Take, for purposes of rough calculation, #=1} mile, 7=80 miles, m=3; the volume is about 133 cubic miles. Conceive this piled up to form a long mound, in section an isosceles triangle 1 mile high, with a base of 4 miles. The length would be over 65 miles. Thus the materials buried in the Bunter beds of the above-named district represent a chain of hills unfurrowed by valleys 5,000 feet high, 4 miles wide, and 65 miles long. Suppose the Pebble Bed, a like slice of a cone, axis one-tenth of a mile, base 70 miles ; the volume is more than 40 cubic miles. Suppose the quartz and quartzite pebbles one-tenth of its volume ; these represent. a mass of four cubic miles, or a line of hills like the above 1,000 feet high, 2 miles wide, and 20 long. ? The lake may have gradually become salt, or possibly the Muschelkalk sea may have for a short space invaded Britain, and then have been insulated like the Caspian. 620 REPORT—1886. suggests that a narrow strait running in a northerly direction may have insulated the Paleozoic rocks beneath the London district. The clays of the Lias, Oxfordian, and Kimmeridgian probably indicate a direct discharge of sediment into the sea,! the limestones, depression sufficing to convert valleys into fjords, in the upper parts of which sediment was deposited so that the waters of the sea were clear. The deposits of the Purbeck and Weald indicate that the western river still drained an extensive area, and a gradual rise of land in later Jurassic times, especially towards the south, appears to have advanced the river delta eastwards, and to have limited the area of the Jurassic sea on the north. Towards the end of the Neocomian, owing to a widespread subsidence, the sea once more returned to South-eastern England, and a communication appears to have been opened between it and the Speeton basin. This comparatively narrow strait was a region of considerable denudation and of strong and shifting coast currents.” The Cretaceous subsidence at first brought back physical conditions not very different from those prevalent in Oxfordian and Kimmeridgian times, but later on a very considerable depression must have so far submerged the northern continental land as either to break up the parts adjacent to Britain into groups of islands, or at least to flood the valleys so completely as to prevent any discharge of sediment into the sea. The erratics of the Cambridge Greensand suggest that a free communica- tion into the northern ocean was established, anterior to the formation of the Chalk marl, through some part of the present interval between Scotland and Scandinavia, so as to set up a coast current with a southerly drift of shore ice near the eastern part of England: to this also may be due the erosion of the Cambridgeshire Gault. The larger part of Britain was dry land during the Eocene, though the sea after retreating appears to have again encroached over the southern and eastern districts of England. The sands may indicate that the western river again resumed its course ;° the extension of the London Clay up our eastern coast suggests that the nurthern river still flowed. But with the important disturbances which closed the Eocene and ushered in the continental conditions of the Miocene—new flexures along the old east and west lines—the earlier physical features appear to have been finally obliterated, and the sculpture of the English lowlands began. The tale of the volcanic outbursts of Western Scotland has been so well told by my friend and predecessor Professor Judd that I need do no more than recall it to your minds, The Pliocene deposits of Eastern England indicate a new encroachment of the Franco-Belgian Tertiary sea. Thus ends my sketch—too lengthy, I fear, for your patience, yet too brief to allow of a complete treatment of the subject. It may, however, suffice to indicate that in geology the ‘task of the least’ is by no means despicable, and that great results may be hoped from apparently small means; that in this search for ‘Atlantis through the microscope’ we may find it very near at hand, and may discover analogies, as has been indicated in our President’s address, between the two borders of the ocean which severs Europe from America. An enlarged study of the materials of our Paleozoic and later detrital rocks may indicate that from very early times there has been a recurrence of similar physical conditions, and that 1 The considerable distance to which the clays extend in a southerly direction may possibly indicate that, to the east of Scotland, a communication had now been opened with the northern ocean, which had set up a current along the coast east of the Pennine chain. 2 As the Speeton beds continue to be clays one would infera drift from the south, but a current to the opposite direction would be more probable, and it is the opinion of Dr. Sorby that this was the case. His papers ‘On the Direction of the Currents indicated by the Coarse Sediments in our British Rocks’ are most valuable (Yorks. Geol. Pol. Soc. v. 220, &e.) A pebble bed sometimes occurs at the base of the Portland series, apparently resembling, though on a very small scale, those in the Neocomian. ’ The occasional beds of flint pebbles indicate a neighbouring shore line of Cre- taceous rocks rather than the denudation of beds of Cretaceous age, which had been deposited on parts of the western land during the period of depression. TRANSACTIONS OF SECTION C. 621 in geology also a recurrence of effects indicates a recurrence of the same causes. The facts which I have brought before you have justified, I trust, my opening remarks as to the rich harvest which yet awaits investigations into the structure of the fragmental rocks. To resume the simile then used, I see the land of promise, stretching far away from beneath my feet, till it seems to melt into the dim and as yet unknown distance. Not speedily will its riches be exhausted. Our hands will long have vanished, our voices will long have been still, before the work of discovery is ended and men have reached the shore of that circumfluent ocean which, at least in this life, limits their finite powers. The following Papers were read :— 1. On the Geology of the Birmingham District. By Professor C. Lapworiu, LL.D., F.G.S. The town of Birmingham lies exactly in the geographical centre of England, midway between sea and sea. This, too, is its geological position, for it is built upon and surrounded on all sides by strata belonging to the New Red Sandstone, the place of which is exactly in the middle of the accepted series of geological formations. To the east of the town lie the gently inclined Neozoic strata of the Jurassic and Cretaceous, &c., dipping in regular order, sheet below sheet, til] they become wholly horizontal in the neighbourhood of London. To the west of the town lie the bent, broken, and more or less altered Paleozoic formations, stretching onwards through Shropshire and North Wales, until they attain their greatest amount of wrinkling and metamorphism in the slaty districts of Snowdon and Anglesea. Within the limits of the Birmingham district itself we find almost every stage of transition between these extreme geological types. In some localities, as in the mid- Warwickshire plain, we find the strata as flat and almost as unaltered as in the day in which they were originally laid down. In others, as at the Lickey, they are folded into steep arches, shattered and faulted; and in others, as in Charnwood Forest, they are crushed into slates. Within a radius of thirty miles of Birming- ham we find representatives of all the geological formations, from the so-called Laurentian and Cambrian up to the base of the Cretaceous. The Carboniferous rocks of the Birmingham district have long formed the accepted model of those British rock formations which are remarkable from the economic point of view. Its ‘Black Country ’ is Dickens’ classical type of a land given over body and soul to mining and manufacture. The local Triassic formation is the British agricultural system par excellence, and the Midland plain of Warwick, Stratford, and Worcester is the heart of sylvan England—the Arden of Shakespeare, and the Loamshire immortalised in the works of George Eliot. Among those who studied the geology of the Birmingham district before the days of the Geological Survey, we find the names of many of those most famous in the annals of British geology:—Professor Playfair, William Smith, Dean Buckland, William Yates, and Sir Roderick Murchison. To Murchison, indeed, the neigh- bourhood was always a favourite one. Its strata afforded him some of the most striking types of the formations and fossils illustrated in his great work, the ‘Silurian System.’ The district was mapped about thirty years ago by the officers of the Geological Survey—by Professor J. B. Jukes (a native of Birmingham), Professor Hull (Director of the Geological Survey of Ireland), and Mr. Howell (Director of the Scottish Survey). Jukes’s ‘South Staffordshire Coalfield’ is one of our modern geological classics ; and Hull’s ‘ Permian and Triassic Rocks of the Midlands’ is the accepted authority upon the Red rocks of Britain. After the survey, until very lately, little geological work was done by Midland geologists. The members of the various local societies rested in the easy assurance that there was nothing more to be accomplished. Within the last few years, however, there has been a great revival of interest. Mr. Samuel Allport’s investigation of the microscopical characters of the Midland volcanic rocks inaugurated the recent revival and brilliant advancement of petrography in Britain. Dr. Holl worked out the detailed geology of the Malvern Hills; Dr. Charles Callaway discovered $22 REPORT—1886. the remarkable Oambrian and pre-Cambrian rocks of the Wrekin; Birmingham geologists themselves have quite recently made several startling discoveries of large areas of Cambrian rocks in much closer proximity to the town; and the interest thus aroused in local geology seems likely to continue. The most interesting geological strata in the Birmingham district are the sup- posed Archzean rocks of the Malverns, Charnwood, and the Wrekin, the Cambrian strata of Nuneaton and the Lickey, the highly fossiliferous Silurian of Dudley, the rich coal- and iron-bearing rocks of the South Staffordshire coalfield, the enigma- tical Permian breccias of the Clent Hills, and the remarkable ‘ Pebble Beds’ of the local Trias. To the north-west of Birmingham the area around Wolverhampton is crowded with innumerable boulders brought down from the Lake District and the south of Scotland. To the south-west of the town, erratics equally abundant are met with, which have travelled from the high ground of the Arenig in North Wales; while relics of the mammoth and other prehistoric animals have been ob- tained from the area east of the town in the excavations of Shustoke. 2. On the Discovery of Rocks of Cambrian Age at Dosthill in Warwickshire.’ By W. Jerome Harxison, F.G.S. The little eminence of Dosthill forms part of the western boundary of the Warwickshire Coalfield. It lies close to the Midland Railway (Birmingham and Burton branch), between the stations of Kingsbury and Wilnecote ; it is two miles south of Tamworth, and twelve miles north-east of Birmingham. On the Geological Survey Map Dosthill is coloured as a mass of greenstone intrusive in the Coal- measures, and bounded on its western side only by a line of fault. On May 29, 1882, the author visited the district for the first time. He found the fault on the west side of the hill very sharply defined, the Keuper Red Marls forming a level plain through which the Tame meanders, and from which the camel- backed ridge of Dosthill rises precipitously. The lowest rock seen near this west fault is a hard grit. Above this we find Cambrian grey shales traversed by innu- merable worm-borings and invaded by igneous rocks. The latter are of two kinds— a tough dioritic rock, and narrow dykes of a grey, much decomposed rock. One section at the south end of the ridge shows a dyke rising through grey Cambrian shales and spreading out above them. The eastern boundary of Dosthill is also a line of fault by which the Coal-measures have been thrown on end and shattered But there is no evidence that the coal-seams have been ‘ burnt,’ as alleged in the Survey Memoir (Geol. Warwickshire Coalfield,’ p. 49). The whole succession of the strata is very similar to that at Nuneaton and Hartshill, on the eastern side of the coalfield, eight miles to the south-east. 3. The Cambrian Rocks of the Midlands. By Professor C. Larpworru, LL.D., F.G.S. Upper Cambrian rocks occur in several localities within the limits of the Birmingham district—at the Malverns, the Lower Lickey Hills, Nuneaton, the neighbourhood of the Wrekin and Shineton, at Caer Caradoc, and Cardington. The core of the Lickey Hills, near Birmingham, is formed of quartzite, formerly believed to be of Llandovery age. This has been shown by the author and Mr. F. Houghton to be actually of pre-Silurian age, rising unconformably from below the basement beds of the local Silurian, and apparently underlain by volcanic rocks of unknown geological age. The sunposed Lower Carboniferous rocks of Nuneaton and Atherston have also been demonstrated by the author and Mr. Harrison to be of Upper Cambrian age, containing the characteristic Agnostids and Olenidz. Detailed descriptions, illustrated by maps, and sections and cha- racteristic fossils, were given of the Cambrian areas of the Lickey and Nuneaton, together with a detailed account of their underlying and intrusive volcanic ' Printed in full in Midland Naturalist, Dec. 1886. TRANSACTIONS OF SECTION C. 623 rocks. The recognisable sequence of the component strata in the several higher ‘Cambrian areas was shown, their physical relations to the underlying and overlying formations pointed out, and evidences adduced in proof of the conclusion that these rocks are fragments of what was originally a single continuous Upper Cambrian formation, composed of corresponding members, admitting of fairly satisfactory correlation with the Upper Cambrian rocks of other districts, and everywhere reposing upon a great volcanic formation, of much earlier date. 4. On the Petrography of the Volcanic and associated Rocks of Nuneaton. By T. H. Wauuzr, B.A., B.Sc. The coarse ashes of the more northern exposures near Hartshill are made up primarily of broken up quartz felsite, the minerals and fragments being cemented in many places by thin films of a green, apparently serpentinous, mineral. The finer-bedded ashes by the ‘Tunnel’ near Caldecote contain broken felspar crystals, in some cases plagioclase, in others orthoclase ; but here the dust seems to have been very fine, especially at times, as some beds appear almost perfectly compact, A little further south still, in a disused quarry, a rock exactly similar in external appearance, and differing microscopically mainly in the appearing ofirregular angular flakes of a green serpentinous mineral, is seen in intimate admixture with a rock having much of the appearance of a quartz felsite. This latter rock, however, has quite abnormal characters except in very few places. Elsewhere the crystals are broken and angular in the majority of cases, and are packed together with a very dirty-looking groundmass among them. The quartz grains are in many cases crowded with very minute fluid cavities, and are indented with the usual bays into which the groundmass runs, in many cases connecting with almost isolated masses within the crystal. The felspar is to a large extent plagioclase, but is much clouded with decom- position products. Some of the greenish flakes have the appearance of decomposed mica. The groundmass where well developed shows good flow structure. Careful examination, both in the field and microscopically, suggests that the andesitic rock mentioned in the next paragraph has flowed over a broken and * partly disintegrated surface of quartz felsite. With these rocks is associated a dark rock, which on examination proves to be composed of plagioclase felspar, and the decomposition products of apparently augite, since a few grains of the latter still remain unchanged. Some of these latter show the twinning that is usual, and also the cleavage parallel to the basal pinacoid which has been described by Mr. Teall in the augite of the Whin Sill close to the junction with the quartz felsite; the rock is distinctly porphyritic, the larger crystals of felspar being set in a mass of very minute felspar crystals, which frequently exhibit the flow of rock in a very marked manner. The porphyritic felspars give extinctions corresponding to Labradorite, or even incline to Anorthite, and have many inclusions which frequently are arranged in lines parallel to the length of the crystal, and are elongated in the same direction. At the base of the quartzite occur beds of conglomerate containin® masses of ashes somewhat coarser in texture than those from the ‘Tunnel’ above men- tioned, and of the quartz felsite. Passing upwards, the felspathic constituent gradually disappears except in one or two bands, and in the typical quartzite but few grains are visible except of quartz. These show by the similarity of the strings of cavities, and, in the lower beds, by the fact that the rounding to which they have been subjected has not been sufficient to entirely smooth away the finger-like indentations of outline, that they were derived from a quartz felsite very ‘similar to, if not actually a part of, the same mass as that previously described. The diorites which are associated with the quartzites are much decomposed, with the development locally of a good deal of calcite. 624 REPORT—1886. 5. On the Rocks surrounding the Warwickshire Coalfield, and on the Base of the Coal-measures.! By Ausrey Stranan, M.A., F.G.S. With an Appendix on the Igneous Rocks of the Neighbourhood, by F. Rur.ey, F.GS. (By permission of the Director-General of the Geological Survey.) The discovery by Professor Lapworth of fossils of Lower Silurian age (Cambrian, Sedg.) in some shales underlying the productive coal-measures of Warwickshire has proved that the determination by the Survey of these shales and of some underlying quartzite as Lower Coal-measures and Millstone Grit respectively was erroneous. The beds had been (previous to the Survey) described by the Rey. J. Yates (‘ Trans. Geol. Soc.’ Ser. 2, vol. ii. p. 237) as Silurian, but in consequence of their apparent con- formity to the productive measures, and in the absence of fossil evidence, were subsequently identified as above, in spite of a correct view as to their age being held by Professor Jukes. A re-examination of the district has proved that (1) the conformability of the Ceal-measures with the underlying shales is apparent only, and not real; (2) the Coal-measures are based by an impersistent sandstone con- taining pebbles, and resting on the denuded surface of the Lower Silurian rocks ; (3) the intrusion of certain igneous rocks (diorites, &c.) in the older series was entirely pre-Carboniferous. The oldest rocks seen are the Caldecote Ieneous Series, which rise from beneath the quartzite between Nuneaton and Hartshill. This series consists of a finely laminated rock, probably a tuff, with intrusions of diabase and quartz-porphyry. Upon this series rests the Hartshill quartzite, with a well-bedded conglomerate at its base, containing fragments of the Caldecote Series. Upwards this quartzite passes conformably into a thick mass of shales, red in the lower, and grey or black in the upper part. In these shales (the Stockingford Shales of Professor Lapworth) have been found fossils, proving them to be of Lingula Flag, and perhaps in part of Tremadoce age. The shales and quartzite are traversed by sheets of diorite, &c., which generally follow the bedding very closely, but are known to be intrusive by the alteration they have effected upon the shales above, as well as below them, and by their occasionally breaking across the beds. The base of the Coal-measures has been proved in a colliery at Hawkesbury, and is seen in the railway-cutting at Chilvers Coton, where a fire-clay, based by a few inches of sandstone, is seen resting on the Stockingford Shales. Further north the workable seams rest almost directly on these shales, but near Oldbury a thick pebbly sandstone, resting with a marked unconformity on shales and diorites, forms the base of the Coal-measures. Further on this sandstone thins out again, but reappears with its former character north of Merevale. A similar relation is found at Dosthill, where, however, the want of parallelism between the Carboni- ferous and Silurian strata is very conspicuous. The impersistent sandstone, forming the base of the Coal-measures here, is coarsely conglomeratic. The descriptions of the base of the Coal-measures of South Staffordshire (Jukes, ‘Geol. Survey Memoir’) is applicable almost word for word to the Warwickshire localities. Towards the east the Lower Silurian rocks are overlain by the New Red Marl and Waterstones, the actual boundary being formed for a large part of the distance by a fault, which has been proved in coal-workings at Polesworth, and is seen ia Merevale Park. This has been wrongly described (‘Coal Commission Report,’ 1879, vol, ii. p. 494) as ‘one of the grandest lines of fault that can be seen anywhere’; it is, on the contrary, a fault of very small importance, especially towards the south. The Trias is seen in four instances to rest naturally on the old rocks, while the same relation has been proved in several borings made in the plain of New Red Marl of West Leicestershire. The result of these observations is to show that it would be useless to search for Coal-measures beneath the Trias over the part of this plain lying south of Market Bosworth, the Carboniferous rocks having either never 1 Published in extenso in the Geol. Mag. Dec. 3, 1886, vol. iii. p. 540. TRANSACTIONS OF SECTION C. 625 extended over the area, or more probably having been deposited in an attenuated form, and subsequently removed in the widespread denudation that preceded the Trias. Appendiz. The Igneous Rocks are divided by Mr. Rutley into Syenitic rocks (Croft Series) ; Andesite and Andesitic Tuffs (Caldecote Series); Diorites, Andesites (or Diorites containing Augite), and Basalts (or Diorites containing Olivine), these three occurring as intrusions in the Lower Silurian rocks, and appearing to graduate into one another. The Croft series includes quartz-syenite and a rock intermediate between quartz-syenite and quartz-diorite. The Caldecote Series includes (1) a finely Jaminated greenish-brown rock, resembling a sandy mudstone, probably an altered andesitic tuff; (2) a rock composed of rounded or corroded crystals of triclinic felspar and quartz-grains in a dark felsitic matrix, and appearing to be a laya-flow or dyke, which has taken up fragments of other rocks in such quantity as to simulate a tuff (the quartz-porphyry previously referred to); (3) a compact purplish-grey rock (the diabase previously referred to), consisting of crystals of triclinic felspar and magnetite in a felsitic ground-mass, which contains minute crystals, believed to be hornblende, in which case the rock would probably be a hornblendic andesite. The rocks intrusive in the Lower Silurian Shales consist of diorite at Marston Jabet, Griff Farm, Chilvers Coton, Stockingford Cutting, Oldbury, and Dosthill. Others, as at Nuneaton Midland Station and in the Stockingford Cutting, are akin to basalt in their composition. The breccia at the base of the Hartshill Quartzite is composed of fragments of eruptive rocks and of slate in a purplish matrix. Quartz-srains constitute a large proportion of the rock. The Hartshill Quartzite consists of irregular crystalline grains of quartz with numerous fluid lacune, with a few grains of felspar. Rarely ' microcrystalline siliceous matter occupies small spaces between the quartz-grains. 6. On the Halesowen District of the South Staffordshire Coalfield. By Wm. Maruews, F.G.8. Details of seven hitherto unpublished sections of sinkings for coal in this dis- trict were given in the paper, and the section of the Old Hawne pits, as set forth in Beete Jukes’s ‘South Staffordshire Coalfield,’ was referred to, These sinkings may be divided into the following groups :— I Sinkings near the western edge of coalfield, Wassell, Oldnall Ridge, 540- G00 feet above sea-level. The figures give the position of the top of the thick coal, or the measures corresponding therewith :— Wassell .. : 4 A . 106 feet above seas Oldnall 3 94 Beeches . - - 1 Wet . 65 az II. - Sinkings in the Halesowen Valley :— Manor . : ; : . - 468 feet below sea. Witley . : : ‘ A . 450 . New Hawne . : : : . do7 A Old Hawne : : : : . 342 o III. Sinking on eastern edge of coalfield :— Rowley Station : ; : . 86 feet below sea. It was shown that the Halesowen Coal-measures lie in a trough, with a steep synclinal section from east to west; and that the various seams which, in their 1886. ss 626 REPORT—1886. ageregate, compose the thick coal show in that district a marked tendency to separate as they extend southwards, and at the same time to become thinner and to deteriorate in quality ; that the Coal-measures rest immediately on the Ludlow Passage beds at Halesowen Manor and Wassell and on the Cambrian quartzite at the Lower Lickey. The paper concluded by a reference to the bearing of these facts on the geological history of the district. 7. Notes on the Rocks between the Thick Coal and the Trias North of Bir- mingham and the Old South Staffordshire Coalfield. By FreprErick G, Meacuam, M.H#., and H. Instey. The most complete sections of these rocks can be seen only in deep sinkings for coal. All other sections in the district expose but little of the rocks overlying the Thick Coal Seams. Taking the rocks in order, we find the following :—Lying upon the Thick Coal is a set of black, greasy unfossiliferous shales, to 11 inches, followed first by grey shales with ironstone nodules and then by alternations of shales and thin flags coated with carbonaceous films and containing a few fossils of the usual Coal Measure types. These are succeeded by some thin seams of fireclay, and then by the Brooch Coal, which is in turn covered by grey earthy shales with ‘ Unios,’ and this, again, by the well-known Stigmaria beds. Grey and blue shales variegated with irregular brown bands overlie the last, and are succeeded by an earthy con- glomerate locally known as the Espley rock. At Hamstead a few seams of fireclay are followed by a representative of the Foot Seam, there only 4} inches thick. This is succeeded by nine feet of black earthy shale, very fissile, and containing a Lingula in abundance, as well as what we take to be casts of Orthoceras, Euom- phalus, Productus, and Spirifer. Casts of Productus occur also in the associated ironstone. Fireclays and black bituminous shales succeed, followed by purple and red sandstones. This is at 72 yards above the Thick Coal. Two feet of blue- grey shale containing Calamites, Lepidodendron, and impressions of sedge-like vege- tation succeed, and are followed by six feet of fireclay. Seven hundred and thirty- two feet of unfossiliferous, variegated marls, with occasional bands of conglomerate, succeed, and are followed by 9 feet of fireclay containing Asterophyllites, Calamites, Cyclopteris, and Neuropteris in abundance. About four hundred feet of variegated marls succeed, and are generally followed by a thin band of limestone containing Spirorbis. More marls, interstratified with hard calcareous bands, rain-pitted and ripple-marked, succeed. These yield TRANSACTIONS OF SECTION D. 689 Hunter, Meckel, Owen, and others have mentioned the occurrence of these extra- numerary teeth. Wedl (‘ Pathologie der Zahne ’) gives a good description of them, stating that whilst six incisors are very rare, five are of more common occurrence, the additional tooth, when of the supplemental group, being generally a lateral incisor. When supernumerary they are placed either amongst the permanent teeth or behind them within the alveolar arch. Their eruption takes place during the first or second dentition, or in the interval between the two; generally, however, they belong to the permanent series. Baume (‘Odontologische Forschungen’) states his belief that the archaic incisor dentition of man was In §, and that the missing teeth are the median In, in each case. This theory he bases upon the facts (1) that a separation may exist between the median incisors in man and the higher apes; and (2) that in this position superfluous teeth may exist. Dr. Edwards, of Madrid, shares his opinion for somewhat similar reasons. Professor Turner, from a study of a number of cases of alevolar cleft palate, believes the missing incisor to be the second, that is, In,. This view is shared by Albrecht and Andrew Wilson. The specimens upon which we base this communication may be arranged in eight groups. We have obtained most of the casts ourselves at the Birmingham Dental Hospital. Others we owe to the kindness of Messrs. Sims and Adams Parker, of this town; Dr. Crapper, of Hanley; Mr. Perey May, of London; and Mr. J. 8. Amoore, of Edinburgh. The groups which we describe are as follows :— (Series i.) Supplemental teeth.—In this group we have one case of six separate incisors (sup. max.), and one of six, the two central being geminous, and seven in which there were five teeth. Of these seven three were on the right, four on the left side. In all the cases save one they were situated behind the true lateral, generally occasioning some displacement. In one case, however, the intruder was placed between the lateral and central. One case only belonged to the milk denti- tion, and all but one were found in the upper jaw. (Series ii.) Supernumerary teeth—We have four casts in which there are two of these teeth: in two they were situated behind the median incisors; in another one was posterior to the left lateral, and a second between the right median and lateral ; and in the fourth one was posterior to the right central, and the second between the two median. In fifteen cases there was one supernumerary. These teeth were situated inside the alveolar arch posterior to the left median incisor in seven cases, the right in five, and in the middle line in three instances. They generally caused more or less displacement of the remaining teeth. All were found in the superior maxilla, and all belonged to the permanent series. (Series ili.) Coeristence of supplemental and supernumerary with the normal number of incisors.—Of this we have one specimen, in which a properly formed though small incisor is placed behind the right lateral, and in series with it, and a blunt tooth posterior to the left median, which it displaces forward. This was in superior maxilla and permanent series. (Series iv.) Substitution of a supernumerary tooth for a normal incisor, the number of teeth remaining fow.—Of this we have four specimens. The substitu- tion was once each for the right and left median, and twice for the left lateral. All the cases belonged to the superior maxilla and to the permanent series. (Series v.) Substitution of two supernumerary teeth for normal incisors, the number of teeth remaining four.—Of this we have six cases, the two lateral superior incisors of the permanent series being those always to suffer. (Series vi.) Adsence of one incisor, the number being three.—In two cases the right lateral (superior) incisor was wanting, and in one the same tooth in the in- ferior maxilla, All three were of the permanent series. (Series vii.) Absence of one incisor, diminution or malformation of another, the number being three.—Of this we have three cases. In two the right lateral was absent. The left lateral was conical in one of these, small but incisiform in the other. In the third case the left lateral was absent and the right lateral small though incisiform. All were of the superior maxilla and permanent series. (Series vill.) Absence of two mcisors, the number being reduced to two.—Of this we have seven cases, all belonging to the superior maxilla and permanent, series, 1886. YY 690 REPORT—1 886. In all the laterals are the missing teeth. The jaws are generally well formed, and there are often gaps between the teeth in the incisor region. The ages of four of these patients were 21, 22, 22, and 17 respectively; of the others we have no exact information, but they were adults. The points which these cases illustrate are as follows :— (i.) Man’s original dentition included six incisors.—This thesis is already fairly generally admitted by odontologists. If supplemental and supernumerary teeth are to be regarded as reversions to the primitive dentition, then in two cases we haye, so far as the superior maxilla is concerned, the complete series. Galton, Wilson, Flower, and Edwards also quote cases of six incisors in the upper jaw. Kirk de- scribes one which occurred in the inferior maxilla and in the milk series. As Wedl remarks, however, the occurrence of six incisors is rare. That of five is, on the contrary, fairly common. What has just been said relates to supplemental teeth, but, as will be seen by a reference to the digest of the series above, a supple- mental and supernumerary may coexist to increase the number of the dentition to six, or two or one supernumeraries may coexist with the normal four incisors. That a milk supplemental may be followed by a permanent successor is proved by a case for which we are indebted to Mr. Amoore. This is interesting as bearing on the development of these teeth. We may sum up by saying that man seldom attains to the archaic dentition of In ¢ in the upper jaw, still more rarely in the lower, never, so far as we are aware, in both simultaneously. On the other hand, in fairly numerous cases, he regains one of his lost teeth, either ill- or well-formed, or both, in an imperfectly formed condition. (ii.) Man’s lost incisor is the lateral or Ing.— Baume and Edwards consider the lost tooth to be In,, mainly on account of a supposed separation existing between the two median. This separation is, in our experience at least, by no means common. Again, in all our cases, whatever teeth are added or suppressed, the medians remain typical in shape. We have also casts showing that the ordinary laterals may take up a position behind the median. This shows that teeth found in this position need not necessarily be abortive medians. These facts, we be- lieve, dispose of the median theory. Two other arguments, shortly to be men- tioned, also make against it. Turner and Wilson’s theory, that the missing incisor is In,, is much more tenable. We are unable at present to explain the facts quoted bythe former authority, but would venture to put forward the following arguments in support of our position :— 1. Tomes bases his theory that, the dentition of man was In £ on the fact that Homalodontotherium possessed that number of teeth, and that the transition from incisors to canine was thus rendered more gradual. Upon these grounds he be- lieves that In, is the lost tooth. Now, if we suppose that In, or In, is missing the force of this argument falls to the ground, unless we believe that, pari passu with their suppression, the others became modified in shape, which there are not facts to prove. 2. It has long been held—and we have fresh facts to show its truth—that the present lateral incisor is now being suppressed. This being so, it seems more reason- able to suppose that the tooth already lost is that which lay behind the present lateral in the original series. 3. Finally—and this is the most important argument—wherever the dentition is increased by two or one incisors, the superadded teeth are behind the laterals, that is, are In,. This is shown in the case where six are present, and still better in one case of five, where the superadded tooth is obviously In,, has no fellow on the opposite side, and affords a perfect example of a tooth bridging over the gap between incisors and canine. (ili.) The loss of incisors ts due to the contraction of the anterior parts of the jaw. —It is well known that the jaws of civilised races are less well developed than those of uncivilised, and that amongst the former the lower have better shaped alveolar arches than the upper classes. These facts are dealt with by Darwin, Herbert Spencer, Oakley Coles, Cartwright, Coleman, Mummery, and Nicholls. We have not had an opportunity of working out the point satisfactorily, but believe this contraction to take place most markedly in the incisive region. Topinard states TRANSACTIONS OF SECTION D. 691 that of the various shapes of alveolar arch the elliptical is most commonly met with amongst inferior, the parabolic amongst superior races; and the former appears to us to afford a far more roomy incisive region than the latter. Callender, in a paper on the ‘ So-called Serpent Teeth,’ has shown how the contraction of the incisive region may occur by arrested growth of the incisive process of the superior maxilla. We suggest that the diminished necessity for the incisors when food is eaten after haying been cooked carefully may account for this suppression. (iv.) Suppression of the two present lateral incisors is taking place——Cope pre- dicts that in the future civilised man’s dentition will be— Inf Ci P2 M8, or Int C2 Pp? M3, and this view is shared by other authorities quoted above. Our series iv.—viii. inclusive bear out this theory very strikingly. In iv. there are cases in which three well- and one ill-formed incisors are present. In vy. two well- and two ill-formed coexist. In vi. one tooth has disappeared. In vii. one is missing, a second malformed, and finally, in viii., two are missing. It will be noticed that of twenty-three cases in these series two only affect the median incisors, Three of the cases are interesting as forming a family group: the eldest, F., zt. 22, has only the two medians; the second, F., et. 20, has lost the right lateral; and the third, I., set. 17, like the eldest, has no laterals. (v.) The conical teeth frequently observed are a reversion to the primitive type of tooth.—It is interesting to note that in the cases of reversion to the archetype or of gradual suppression, a tooth unable to reach full development may remain of the conical form characteristic of lower dentitions than the human. This reversion is not peculiar to man, as we have a skull of a Midas Rosalia in which an additional premolar of a conical shape exists on one side. To sum up, our conclusions are as follows :— 1. Man’s original dentition included six incisors. 2. Man’s lost incisor is the lateral or In,. 3. The loss of these incisors is due to the contraction of the incisive region of the alveolar arch. 4, Suppression of the two present lateral incisors, in the upper jaw at least, is at present taking place. 5. The conical teeth, supernumerary (Wedl, ‘ Dutten-oder Zapfenzihne’), fre- quently observed, may be looked upon as a reversion to the primitive type of tooth. 2. On the Nervous System. of Myzine and Petromyzon. By Professor D’Arcy THOMPSON. 3. On the Vestigial Structures of the Reproductive Apparatus in the Male of the Green Lizard. By Professor Howss, F.L.S. The author describes in detail a specimen in which the two oviducts were fully developed. He demonstrates for the species a series of stages in the development of the same identical with those recorded for the male toads and frogs by Van Wittich, Marshall, and others. He claims that the constant tendency towards the fuller development of the oviducts on the part of the male—so prevalent among the higher vertebrata—points not towards an ancestrally hermaphroditic condition, but rather towards one most nearly represented in the adult males of the living Ganoids and Dipnoi. 4. On the Development of the Skull in Cetacea. By Professor D’Arcy THompson. 1 Published in the Journal of Anatomy and Physiology, Jan. 1887. 2 or 692 REPORT—1886. 5. On some Abnormalities of the Frog’s Vertebral Column.} By Professor Howes, F.L.S. Two cases were described. In one a supernumerary (Xth) vertebra was de~ veloped, which had usurped the function of the true sacral one; the latter had established its customary connections on one side only, and the accessory processes to be accounted for were shown to be the resultants of an attempt to make good the loss by failure to do so on the other. In the second case the urostyle had ‘ slipped’ and was displaced dorsally. Instead of becoming buried in the adjacent soft tissues, or ankylosed to the neighbouring bony ones, it had entered into a new connection with the sacrum—the body of which was prolonged upwardly into two new articular facets. The process was held to be tantamount to that of reproduc- tion of a lost part so familiar among invertebrates. MONDAY, SEPTEMBER 6. The following Papers were read :— 1. On the Brain of an Aboriginal Australian. By Professor Macauistmr, F.R.S. 2. On Heredity in Cats with an Eutra Number of Toes.? By E. B. Poutron, M.A. Observations on this subject were brought before the notice of the British Association in 1883, the complete account being published in ‘Nature’ for November 1 in that year (p. 20). The abnormality had been then traced through six generations, and the stock in which it appeared through two earlier generations. The observations have been continued from 1883 until the present time, resulting in a large addition to the eighth generation, which now contains five families, and in the appearance of one family in a ninth generation. A very high proportion of abnormality continues in the recent families, and in the latest of all there are two kittens with seven toes on the forepaws and six on the hind; while in the last family of the eighth generation one kitten possessed seven toes on each forefoot and seven on one hind foot, with six on the other—the greatest abnormality which has come under my observation, although an even larger amount (seven on both hind feet) is on record in the same stock, 8. On the Artificial Production of a Gilded Appearance in certain Lepi- dopterous Pupe. By HK. B. Pounroy, M.A. A few years ago Mr. T. W. Wood brought before the notice of the Entomo- logical Society of London some proofs that certain pupz resemble the colour of the surface upon which pupation takes place. This conclusion was received with some incredulity by many leading entomologists, but without sufficient reason. For the last few years I have been working upon the colour of larve in relation to the colour of their surroundings, and I have shown that the colour may be modified in one generation (in certain species) by an appropriate alteration of the surround- ings. Itseemed very probable from these experiments that the larvee were affected by their surroundings through some sensory surface, and that by means of a nervous circle a corresponding colour effect was wrought. It appeared to be very likely that Mr. Wood’s observations were but a special case of those general methods of protection which I had been investigating. Mr. Wood explained his observations by supposing that the moist surface of a freshly exposed pupa was photographically 1 Published in the Anatomischer Anzeiger, vol. i. Part XI. 1886. 2 The complete account of ail the families, with figures of the abnormal paws, is published in Watwre for the week ending Noy. 13, 1886. TRANSACTIONS OF SECTION D. 693 sensitive to the colour of surrounding surfaces. Such an explanation appears to be merely a metaphor borrowed from photography, and it is furthermore unsupported by any proofs. There is, in fact, much @ priori exception to be taken to it, inasmuch as it implies that all those pupe which throw otf the larval skin on a dark night must lose the advantages of this form of protective resemblance. It is much more probable that the effect is produced by the action of surrounding colours upon the larva during the time (long enough to include many hours of daylight) in which the latter rests upon the surface where pupation will take place. In the first place, I made many experiments in order to test the accuracy of Mr. Wood’s observations, resulting, as I had anticipated, in the most complete confirmation. Among the pup experimented upon was that of the common tortoiseshell butterfly (Vanessa urtice). It was found that by causing pupation to take place upon a white or black screen very different results could be produced. The pupz upon the white screen were often brilliantly golden, and quite unlike all the ordinary forms assumed by this species, and well known to entomologists. Curiously enough, however, the pup of this and other species, which are full of parasitic larve of ichneumons, and which can never produce butterflies, are often as brightly gilded as those upon which I experimented. But my pups were perfectly healthy and produced normal butterflies. Considering the effects of my first experiments, it appeared probable that an artificially gilded surface would produce even stronger results than a white sereen, and experiment soon confirmed this prediction. Such a result seems to imply that the metallic lustre of many exposed pupz harmonised with equally brillant objects among the vegetal oy, more probably, the mineral surroundings. The next point was to ascertain the period during which the larva was sensitive, and incidentally to confirm in the mdst complete way my suggestion that these effects are due to the larva itself, and not to the freshly formed pupa. These objects were achieved by transplanting the larva at various periods before pupation from one surface to another, which was\known to produce an opposite effect. Tt was thus found that the larve are sensitilye for many hours—even more than a day—before pupation takes place. It was then necessary to ascertain if possible the nature of the larval sensory surface which is affected by surrounding colours ; and, first of all, the ocelli were eliminated by covering them with an opaque varnish (renewed if necessary), but this treatment did not affect the result. Hqually in- effectual was the result of snipping off the larval bristles, which it was thought might possibly contain the desired sense-organ. Then another method was adopted : as soon as the larve suspended themselves head downwards (many hours before the change takes place), they were surrounded by tubes so constructed that the head and anterior part of the larva were contained in a gilt chamber, while the rest of the body was surrounded by black walls, tending to produce an opposite effect, the two compartments being separated by a perforated disc which just allowed the larval body to pass through. The head in the lower chamber was always turned on one side, so that the colour of the upper compartment could not possibly affect it. In other cases the colours of the compartments were reversed. When I first looked at the pup in these tubes I fully believed that the colours followed those of the chamber in which tlie larval head had been, and I was much puzzled by this, inasmuch as the only likely sense-organ—the ocelli—had been already eliminated by previous experiments, But when the pups were taken out of the tubes, and placed side by side upon white paper, I found that the effects I have described were entirely misleading, being due to reflection from the walls of the lower chamber when gilt, and to a dark appearance due to the surrounding black surface in the other cases. The negative result obtained seems to indicate that the sense organ exists in the skin, or that possibly the light acts in a more direct way upon the larval skin without the intervention of the nervous system. The full results of the investigation will not, however, be obtained until an immense amount of work has been bestowed upon the notes made during these experiments, in which many hundreds of individuals have been employed." 1 See Proc. Roy. Soc. No. 237, 1885, and No. 243, 1886, and Trans. Ent. Soc. Lon- don, Pt. I. 1884, Pt. II. 1885, and Pt. If. 1886 for the experiments and observations upon larval colours alluded to above. 694 REPORT—1886. 4. Some Experiments upon the Protection of Insects from their Enemies by means of ai unpleasant taste or smell. By EH. B. Poutron, M.A. When working up the historical side of this question my attention was directed towards the necessity for further experiments. Wallace had predicted that bril- liantly coloured and conspicuous insects would be refused by the ordinary verte- brate enemies of their class—that, in fact, the gaudy colouring acts as a warning of the existence of something unpleasant about its possessor. Conversely, Wallace argued that insects which were protectively coloured, resembling their surround- ings, would be eaten when detected. It appeared that experiments (conducted by Mr. Jenner Weir and others) yielded the most complete proof of the existence of these sharp distinctions. But on thinking the whole subject over it seemed to me that the acquisition of an unpleasant taste or smell, together with a conspicuous appearance, was so simple a mode of protection and yet, ex hypothest, so absolutely complete, that it is remarkable that more species have not availed themselves of this means of defence. What could be the principle which worked in antagonism to this mode of protection? For in Wallace’s theory no suggestion of a true counterbalancing limit appeared, ¢.e., one which increased with the increasing application of this method of defence until the latter was checked, or for the time being rendered of no avail, or even turned into an absolute danger. But if a very common insect, constituting the chief food of one or more vertebrates, gained an unpleasant taste, the latter animals might be forced to devour the disagreeable objects in order to avoid starvation. And the same thing might readily happen if a scarce and hard-pressed form adopted the same line and so became dominant, after ousting many species which were much eaten by vertebrates. If once the vertebrate enemies were driven to eat such an insect in spite of the unpleasant taste, they would certainly soon acquire a relish for what was previously disagree- able, and then the insects would be in great danger of extermination if in the mean- time they had become conspicuous by gaining warning colours. If this reasoning be correct it follows that this mode of defence is not necessarily perfect, and that it depends for its apparently complete success upon the existence of relatively abundant palatable forms. In other words, its employment must he strictly limited. In order to test my argument I determined to experiment with a view to ascertain whether hunger would drive a vertebrate to eat an insect which was evidently unpleasant to it. T obtained a few different species of Italian lizards and some tree-frogs, and very soon found that I had reasoned correctly. The lizards would often refuse a conspicuous insect at first, with all the signs of repugnance, but would afterwards make the best of it, when they were not supplied with other food which they liked better. I sometimes found this to be the case with species (eg., larva P. Bucephalus) to which other observers have ascribed the most complete immunity. I should add that it has been always recognised that an insect may be distasteful to one vertebrate enemy but palatable to another, and to this extent Wallace admits a limit to the application of his principle of defence. But the limit which I have proved is of course entirely different, for I have shown that the vertebrate may be forced to eat the insect, although unpalatable to it. Although the latter limit is thus quite distinct, it would certainly in time become identical with the former, for, as I have argued above, the unpalatable forms when eaten would soon become palatable. I have, in fact, shown how the limit which Wallace himself admits has grown up, and how it may become a counterbalancing principle, working against and perhaps reversing the principle which he was the first to point out as of general application in insects. Some quite new modes of defence came out during the inquiry. Thus size alone seems to act asa protection: a large moth (S. ligustri), evidently palatable and quite harmless, was untouched by small lizards, but eaten by larger ones. Again, it is probable that a species may acquire protection by causing digestive troubles after being eaten, rather than by having an unpleasant taste, and it may be that the former effect would leave an even more indelible effect than the latter upon the memory of the captor. Some experiments with the frogs rendered this conclusion probable (£. Jacobee imago being used). Another result at first surprised me very much; it was a limitation to the TRANSACTIONS OF SECTION D. 695 universal application of Wallace’s second prediction. I found that certain species which are well protected by resembling their surroundings, were nevertheless also protected by an unpleasant taste (e.g., larva of M. Typica, imago of P. Bucephalus) and were only eaten with reluctance in the absence of other food. I have given a brief abstract of the results of my experiments, which on the whole confirm the general principles which Wallace laid down, but show that there are other principles which may work in antagonism and prevent the applica- tion of the former, or may even reverse their action. I have also shown that these two methods of protection are not always sharply demarcated or mutually exclusive, as was previously believed to be the case. 5. On the Nature and Causes of Variation in Plants.' By Parrick GuDDES. In this paper (a preliminary outline of a more extended analysis underlying the writer’s essay on ‘ Variation and Selection,’ in preparation for a forthcoming yolume of the ‘Encyclopedia Britannica’) it was first pointed out that while the fact of the origin of species by evolution was no longer disputed, nor the operation of natural selection upon organic forms any longer denied, the absence of any general theory or rationale of variation in either the animal or the vegetable world was not only generally admitted, but often regarded as inevitable or even hopeless : variation to some writers being simply ‘spontaneous’ or ‘ accidental ;’ to others, if id at least dependent upon causes lying beyond our present powers of analysis. A theory of variation must deal alike with the origin of specific distinctions or those vaster differences which characterise the larger groups. To commence, then, with the latter, we may propose such questions as, e.g.—(1) How comes an axis to be arrested to form a flower? (2) How is the evolution of the forms of inflorescence to be accounted for? (8) How does perigyny or epigyny arise from hypogyny ? (4) How is the reduction of the oophore and differentiation of the sporophore to be explained among cryptogams and phanerogams, and why should the moss type be so aberrant and so comparatively arrested? (5) How do angiosperms arise from gymnosperms? (6) How are the forms of fungi, algw, &c., to be accounted for? and soon. The explanation was shown to lie not in the operation of natural selection upon accidental variation, requiring separate explanation in every case, hut upon that general and familiar antagonism between reproduction and vegetative growth further analysed (in the writer's subsequent paper ‘On the Theory of Sex and Re- production,’ and ‘Encyclopedia Britannica’ article Srx) to its basis in the con- structive and destructive metabolism of protoplasm. It was shown by the aid of diagrams that in all such cases as those above mentioned, the reproductive axis, organ, tissue, &c., in every case tended to become more and more shortened, depressed, or hollowed in proportion to the vegetative. This conception was further developed, and shown to apply alike to the construction of the general genealogical tree, and in particular to the affinities of the flowering plants; and very frequently to the interpretation of minute details of floral structure usually regarded as the product of natural selection on spontaneous local variations, the common Geranium sylvaticum being selected as a case in point. 6. The Honey Bee versus Darwinism. By the Rev. T. Mirus. 7. On the Biological Relations of Bugio, an Atlantic Rock in the Madeira Group. By Dr. GRABHAM. Reasons for Writing.—Because seldom visited though possessing special interest, and because considered typical of insular flora distribution and variation by Lyall and others. 1 See writer’s paper bearing same title as the above in Trans. Bot. Soc. Edin. 1885-6 696 REPORT—1886. Author proposed to illustrate recent accumulation of facts and variations by reference to prominent instances of distribution, &c., from one of the smallest and most inaccessible rocks of the group. Physical Characters of Dezertas Origin—Foundation on a narrow ledge dimensions not much changed, no evidence of contact or union, not survivals of an ancient continent. Islands in a Miocene sea, deriving their colonists from Miocene Europe. Description of Bugio.—Dimensions, formation, central volcanic dike, difficulty of access, large proportion of tufas; no sections of old river-beds or surface obliterations, Summit showed deep clay-beds and surface deposits of calcareous earth and sands, with ‘ fossils,’ so called, of Madeira. Flora.—Relation to Madeiran, arbitrary distribution, absence of easily wafted forms. Senecio incrassatus, form of, how related to Madeira and Canary Islands. Echium fastuosum, maritime form of; relations to other Madeiran Echia. Hybrid with E. simplex, deriving perennial characters and change of colour and habit. Jasminum oderatissimum, Mesembrianthema, as instances of fitful distribution. Chrysanthemum hematominmata, a distinct and only species, description of, and remarks on cognate Madeira forms. Monizia edulis, Dezertan, Salvagic and Madeiran examples and varieties. Description of, Miocene origin of. Fauna.—Mischieyous presence of goat and rabbit. Feral character of rabbit, reference to Darwin’s description of, identical with that of Porto-santo, description of. Sea Bords.—Sternus hirundo. Thallassidroma Bulwerii and many other Petrels ; existing confusion of species in Loudon. Procellaria Anglorum dominant at Bugio, excluding P. major and P. obscura. Influence of, on migration of plant- species; size of ege and form. Testacea.—Helix crystallina, affinities ; H. leonina, distribution ; H. erubescens, distribution ; II. punctata, modification of; H. vulgata, dwarfed sub-fossil ; H. polymorpha, Bugian form; H. coronata, description of, and affinities to H. Grabhami and others. Coleopterous Deucalion, species of, how related to Salvagic form. Short Summary.—The above instances show the difficulties attending studies of the presence, origin, and variation of fauna and flora from a single point, to be equally great locally as between the archipelago itself and an ancient continent. Agency of Man, ancient and modern. Destruction of cover and food in vegeta- tion; contaminating introductions. Man obvious chiefly in extinction; instances from St. Helena as well as Madeira. Ravages of Eupatoria and Phylloxera in Madeira, and of other species. Surviving vigour of Miocene forms of plants. Author’s paper only meant to be indicative, and does not pursue any branch in cee though the history of any variety would profitably occupy the time of the ection. 8. On some new Points in the Physiology of the Tortoise. By Professor Haycrarr. 9. Preliminary Account of the Parasite Larva of Halcampa. By Professor Happon. 10. Notes on Dredging off South-West of Ireland. By Professor Happon. TRANSACTIONS OF SECTION D. 697 11. Points in the Development of the Pectoral Fin and Girdle in Teleosteans. By Epywarp E. Prince. Ata very early stage, and long before liberation from the ovum, the pectoral fins can be distinguished in Osseous Fishes as a pair of flattened pads projecting horizontally from the trunk, some distance behind the otocysts. Their position seems to vary in different species,’ but a considerable interval always separates the early fins from the auditory organs, or rather from the true pectoral region. They are differentiations of a continuous lateral expansion of epiblast passing along each side of the trunk, and are formed by the folding of this epiblastic layer upon itself at the point where the fins appear. Lach fin consists therefore of two epiblastic lamelle (separated by a fissure) lying flat upon the vitellus, and continuous with the extra-embryonic blastodermic membrane. The fins soon assume a denser appearance as mesoblastic cells push their way into the median fissure, separating the upper from the lower lamella of the fin. These mesoblastic cells are certainly not splanchnopleuric, but as no well-marked somatopleuric crest has been recognised in fishes comparable to the Wolffian ridge of higher forms, they seem to be derived from the intermediate cell-mass in close proximity to the Wolffian ducts. As the fin becomes stouter its position alters, its lengthy lateral attachment to the trunk diminishes, while it becomes pedunculate and stands erect, though not quite vertically. The distal portion of the fin is very thin and transparent, save at the periphery, where, at the junction of the upper and lower lamelle, the epiblast cells are approximated so as to form a marginal ridge probably connected with the subsequent development of dermal fin-rays. Meanwhile the fin progresses over the interval before mentioned to a point immediately behind the auditory organs, and the well-known rotation of the fin is accomplished, so that it now projects obliquely in a dorso-ventral direction almost parallel to the plane of the branchial arches in front. The gradual shifting of the fin from its original place brings it into close relation with a band of mesoblastic cells, which passes obliquely behind the otocysts, and is called by Ryder the ‘ oblique or vertical pectoral fold.” In this fold cartilage-cells appear, and extend dorsally and ventrally. To the cartilaginous pectoral bar, thus formed, the fin-plate becomes attached, and simultaneously a median stratum of mesoblast in the latter is converted into cartilage, which, by its basal portion, articulates with the girdle. It is noteworthy that each half of the pectoral arch originates independently, nor do they approach each other in the middle ventral line until a much later stage. A strong plate of translucent ectochondral bone, like a curved bar of chitin, develops and ‘becomes attached to the scapulo-coracoid rod, and the subsequent reduction of the latter (the primary cartilaginous girdle) produces much complication in the adult structure. Without desiring to lay undue stress upon the suggestions afforded by the development of the anterior limb and its girdle in forms so highly specialised as the Osseous Fishes, it is still of interest to note their bearing upon accepted theories as to the true nature of the fin and its related arch. ; Support is thus certainly given to the continuous lateral-fin theory of Balfour, for the fins arise in connection with longitudinal epiblastic ridges extending in a horizontal plane? from the trunk of the embryo, while their independent origin is adverse to Gegenbaur’s view that they spring from a branchial arch and are modified gill-arch elements. Owen, more than a quarter of a century ago, com- eo the branchiostegal rays springing from the hyoid arch to the ‘ pectoral fin iverging from the hzemal arch’ (2.e., the pectoral girdle); but Balfour’s view (which is also that of Dohrn and Mivart) receives more countenance from Teleostean embryology. Dohrn, however, not only regards the fins as aggregations of a long lateral fin ; but supposes that the coalesced fins became connected with underlying gill-arches which ancestrally extended beyond their present limits. Gegenbaur 1 The forms especially referred to by the writer are certain species of Gadus, Pleuronectes, Cottus, &c., studied at the Marine Laboratory, St. Andrews. _ #® This position is, according to Gegenbaur’s view, secondary, whereas in Teleo- steans it seems to be primary, and the vertical position is assumed secondarily. 698 REPORT—1886. also derives the pectoral girdle from a branchial arch, and, according to both authorities, this arch must have shifted to the surface from a deeper plane of origin, for the girdle is essentially a superficially placed structure. ‘The visceral cleft system arises more deeply, and is hypoblastic, the gill-arches being developed in the splanchnopleure, whereas the cartilaginous pectoral girdle is somatopleuric, if the cells, from which it originates, are to be distinguished from the adjacent intermediate-cell mass. There are many difficulties in deriving the fin from branchial arch appendages, even so primitive a girdle as that of Ceratodus having no directly articulating rays, comparable to branchiostegal elements, and there are difficulties no less in assigning a branchial origin to the shoulder-girdle itself. The girdle arises as two separate rods, external to the heart and the alimentary tube, and passing dorso-yentrally. Its two elements originate, indeed, precisely like a pair of strongly developed ribs, for the ribs begin as ossifications at independent centres in the intermuscular septa, and grow both ways, dorsally to unite with the vertebral bodies, and ventrally to meet or remain separate, as the case may be. In exactly the same way the scapular and coracoidal halves of the pectoral bars develop to subserve the same function—viz., that of providing a support in connec- tion with the movements of the body. The attachment of the pectoral girdle to the skull recalls the connection of un- doubted rib-elements with the skull in Carps and Siluroids. Can we not refer the two halves of the pectoral girdle to the axial skeleton as strengthened and modified costal rods,! possibly equivalent to many coalesced ribs, to which the fins, originating independently, become secondarily attached? It is significant that the Cyclostomes are destitute of ribs, and they possess no limbs; and this accords with the above suggestion, for if no ribs exist, no limb-girdle could be developed from them. In the Selachians it is noteworthy that the ribs seem to have suffered great degenera- tion. Whether a costal or branchial origin be attributed to the pectoral girdle, the appended limbs are wholly separate structures, and only become related to it after changes in shape, position, and function of the most remarkable character. 12. Some Remarks on the Egg-Membranes of Osseous Fishes. By Rosert Scuarrr, Ph.D., B.Sc. It is no doubt due to the transparence and the extreme smallness of the objects that so many different opinions prevail on the structure of the Teleostean ovum. All authors, however, agree that a membrane surrounds the ege, which in many if not in all cases, is pierced by minute canals or pores. The name most generally adopted by zoologists for this membrane is ‘ zona radiata,’ which I think is a much more suitable one than ‘ vitelline membrane,’ or ‘ yolk sac,’ for reasons which I shall give presently. In the ovum of the gurnard (Zrigla gwrnardus) I could distinctly see with a high power a very delicate homogeneous membrane internally to the ‘ zona radiata,’ In the ripe egg, or rather in the fully-grown intra-ovarian egg, it covers the proto- plasmic layer known as the ‘ Rindenschicht,’ or ‘ periblast,’ which is one of the later modifications of the yolk. Ransom was the first observer who not only saw a similar membrane in various Teleostean eggs, but also isolated it. Some of the later observers failed to make it out; others, again, confirm Ransom’s observations. As long as any doubts exist as to presence or absence of this inner ‘ yolk sac’ of Ransom, the ‘ zona radiata’ should not be called a vitelline membrane. The latter term, however, might very well be applied to the inner membrane which I have just mentioned. It corresponds to a cell-membrane, and is, therefore to be con- sidered as a vitelline membrane. In the gurnard as well as in the cat-fish (Anarrhichas lwpus) the zona radiata showed an external portion which stained darker, and through which the pores piercing the inner part were apparently continued. This outer part was sometimes 1 Prof. Humphry, of Cambridge, hinted at a connection of certain elements in the coalesced lateral fins (that is to say, the median longitudinal fins) and the ribs in the Jowrn. of Anat. and Phys. vol. x. p. 671. TRANSACTIONS OF SECTION D. 699 separated from the inner in cross-sections, and the pores were frequently obliterated by numerous very fine granules contained init. In the ripe egg of the cod (Gadus morrhua) only one thin membrane is visible, which, as far as I could ascertain, is not porous. I am not quite convinced that the pores are really absent in this case, as I only examined spirit specimens, but it occurred to me that what we see here is really only the outer denser part of the zona radiata, the inner portion haying become absorbed during development. That such a thing might happen has been fully demonstrated by Balfour in the egg of Scyllium. Balfour's vitelline membrane is equivalent to the outer part of the zona just mentioned. Both of these seem to become absorbed in some of the Elasmobranch eggs during later development. With regard to the Teleosteans I might mention that, in case the presence of a true vitelline membrane should be definitely established in all intra-ovarian eggs, the zona radiata is to be regarded as a cuticular formation of the ovum. Every intra-ovarian egg is surrounded by the follicle or granulosa, which is a cellular layer. In a paper which I propose to publish shortly, the formation of the yolk will be fully considered along with some remarkable changes which take place in the nucleus of the growing egg. TUESDAY, SEPTEMBER 7. The following Papers were read :— 1. On Humboldtia laurifolia as a Myrinekophilous Plant. By Professor F. O. Bowrr. It is already well known that the hollowed and swollen internodes of Hum- boldtia laurifolia are inhabited by small black ants. ‘The questions which present themselves with regard to this symbiosis are—Ist, How do the hollows originate ? 2nd, Is the presence of the ants of any advantage to the plant? An investigation of young shoots shows that the opening, through which the ants enter, is formed by rupture of the superficial tissues, owing apparently to pressure from within, and that the ants thus gain access to and hollow out the pith which had previously begun to decay. Thus the plants take the initiative, and the ants are not slow to avail themselves of the opportunity offered. Further, from the numerous glands on the leaves it is probable that they derive food, and are thus supplied with both nourishment and lodging. No evidence is forthcoming, however, that the symbiosis is of any advantage to the plant. The stipules in this plant are of a peculiar form ; a study of their development shows that a peculiar auricle-like outgrowth is formed at the base of the simple, young stipule, subsequently to the origin of the latter. Though this assumes a peculiar, almost sagittate form, still in its real nature it is similar to those auricles which are formed at the base of the stipules of Viola tricolor. 2. On Positively Geotropic Shoots in Cordyline australis. By Professor F. O. Bower. It was noticed in Peradeniya Gardens that when, by reason of the weight of the head of leaves, stems of Cordyline australis assumed an oblique or horizontal position, shoots were formed from the lower side pointing directly downwards. It was ascertained that these were in their origin axillary. By hanging pots of soil in such a position as to immerse the tips of these shoots, an elaborate root system was soon formed, the roots arising in the usual manner. In the cases observed the apex of the shoots remained covered with scale leaves, and the ultimate fate of it is uncertain. It is clear that here we have a special adaptation for mechanical and physiological support of a weakly axis, and in this respect we may compare 5 700 REPORT—1886. the cases of Ficus and Pandanus, and also of Rhizophora, though it is to be noted that in Cordyline shoots are the members employed, while roots are used in the other cases named. 3. Note on Apospores in Polystichum angulare, var. pulcherrimum. By Professor F. O. Bowrr. Specimens were shown illustrating the above peculiarity, which has been recently observed in a plant from a locality quite distinct from that where the original plant was taken some twenty years ago. 4, On the Formation and scape of the Zoospores in Saprolegnic. By Professor Hartoa. 5. On the Germination of the Spores of Phytophthora infestans. By Professor MarsHatt Warp, M.A. 6. Two Fungous Diseases of Plants. By W. B. Grove, B.A. The first was the ‘ Eucharis disease,’ which has been shown by the author to be due to the fungus, Saccharomyces glutinis. It attacks other bulbs besides Eucharis, and may be known by producing reddish spots. It can be killed by growing the bulbs in a considerable heat, or by sulphide of potassium. The second was a ‘ Viola disease,’ attacking cultivated species of Viola, It is due to an Qicidium and its accompanying Puccinia, known respectively as CEeidium depauperans and Puccinia eyra. It has only been observed in two or three districts, as yet; and does considerably more harm to its hosts than the similar disease which is common on Viola canina. 7. Preliminary Notes on the Autumnal Fall of Leaves. By Professor W. Hitiyousn, M.A., F.L.S. So far as these experimental investigations—commenced in the autumn of 1882 and still m progress—are concerned, the question of the autumnal fall of leaves has been approached from two standpoints. (1) The mechanism of leaf-fall. (2) The transfer of the cell-contents from the leaf. (1) The Mechanism of Leaf-fall—tt appears to be certain that the dissociation of leaf and branch takes place by the formation, by means of renewed cell-diyision in the basal plane of the leaf-stalk, of a layer of cells, which the author proposes to call the absciss-layer. The absciss-layer is produced by new dividing walls being formed across the cellular tissue of the base of the leaf-stalk. It is clearly recog- nisable, not merely by means of these walls, but also by its marked quantity of pro- toplasm, and the presence usually of numerous small grains of starch. The exact position of the absciss-layer slightly varies, always outside the periderm line of the branch, and usually sloping inwards and upwards. It is formed usually very shortly before the fall of the leaf. In some cases no absciss-layer is formed, and the leaf does not fall normally. The formation of the absciss-layer may be either preceded, sometimes by a fair interval of time, or succeeded by the formation, on the stem side of it, of a periderm; this likewise by new dividing cells being formed in a pre- existing cellular tissue. This periderm lies usually more or less in the line of that a ake, branch, and becomes continuous with it. The cells outside the periderm shrivel. The author's experiments tend to show that the fall of the leaf arises from the increased turgescence of the cells of the absciss-layer, owing to their osmotic activity. These become strongly rounded; their adhesion equally diminishes, TRANSACTIONS OF SECTION D. 701 This turgescence appears to arise from root-activity continuing, after the transpira- tion, or rather conducting, power of the leaf, for reasons hereafter noted, has been in the main lost. The presence of water in the living cells of the absciss-layer is so much the greater from their being bounded by cells which are practically dead ; and whereas the rounding of two living cells in contact need not destroy their power of cohesion, the rounding of a living cell in contact with one which is dead would probably cause complete separation. The soft elements of the vascular bundles are either pinched, or else cell-division takes place in them also. The lignified elements undergo changes, the nature of which I am not yet able to explain satisfactorily, and then rupture with the strain. (2) The transfer of the cell-contents from the leaf—In leaves about to fall, starch is always found in the sieve-tubes, mainly collected in cloudy, granular- looking masses in the neighbourhood of the sieve-plates. With iodine these grains do not stain violet, but brown or reddish-brown. The accumulation is commonly ‘greatest on the leaf side of the sieve-plate. To be devoid of starch is usually the first sign of a leaf being ready to fall. In all cases where tannin is present in the leaf, it is present, and with the same distribution, in the fallen leaf. Tannin and starch are especially abundant in what I will call the food-layer at the base of the leaf-stalk, in which the absciss-layer and cork-layer are formed. In naturally fallen leaves starch is rarely found, except right at the very base of the stalk, and then in very small grains. Taking in all cases precautions against prematurely fallen leayes, perfect nuclei are comparatively rare in fallen leaves, though in some cases (e.g., Salisburia adiantifolia, Acer platanoides, Catalpa bignoniotdes, Quercus pedun- culata, and Ficus Carica) perfect nuclei are general in blade and petiole. Cells containing no nuclei have, however, very commonly a number of larger or smaller irregular fragments of proteid matter, staining deeply with ammonia-carmine or methyl-green. In many cases, where the nuclei are apparently perfect, they show manifest granularity, and often irregularity of outline. The evidence tends thus to show that the nucleus, or at least the chromatin, is left behind in the empty cell, the nucleus tending to what we will call ‘disintegration,’ as distinguished from ‘fragmentation’ or direct division, this latter being by no means a sign of the death of the cell. Nor does disintegration bear any relation with the fragments of nuclear substance found in many pollen-tubeg which show no nucleus, nor with the scattered small grains, which perhaps replace the nucleus in many Chroococcacee, Nostocaceze, &c. Perhaps a strict classification would require to divide the terms ‘direct division ’ from ‘ fragmentation,’ both possible in living cells. It is interesting to note in this connection that from the leaves of the few ever- greens that I have thoroughly studied, starch is likewise usually absent in winter, being transferred to the stem, the tannin, on the other hand, remaining behind. 8. On an Apparatus for Determining the Rate of Transpiration. By Professor W. Hitiuovuse, M.A., F.L.S. 9. On the Cultivation of Beggiatoa alba. By Professor W. Hittuousr, M.A., F.L.S. This bacteriad is especially found on decaying alge, &c., in sulphur springs and waters receiving the refuse of factories. It is comparatively large, the threads varying in thickness from 0:001 to 0-005 mm., and hence is very suited for labora- tory purposes in teaching. Though normally in the form of segmented threads, attached to a substratum, it illustrates the most modern conceptions of bacteriolo- gists (Cohn, Zopf), showing, in various stages of its existence, coccus forms, rodlets, spirals, swarming movements, and even creeping movements, which much resemble those of the oscillarians. For laboratory work it can be kept growing continuously and with certainty upon fragments of india-rubber tubing in water, upon which it will usually appear spontaneously after the lapse of a few months. 702 REPORT—1886. 10. On Heterangium Tiliordes. By Professor W. C. Wituramson, LL.D., F.R.S. In part iv. of my series of memoirs in the ‘ Philosophical Transactions’ I pub- lished a description of a remarkable stem from Burntisland, to which I gave the name of Heterangium Grievii. More recently we have obtained a second and yet more interesting species of the same genus from Halifax. In many respects it agrees closely with H. Grievii, especially in the structure of its central axis and its exogenous zylem-zone. Its distinctive features are chiefly confined to the bark and phloem-zone. In H. Grievii I found no traces of a true phloem, but such a zone is fully developed in the new species, to which I propose to give the name of Heterangium Tilioides, The vascular zone is abundantly furnished with medul- lary rays of various sizes. The largest primary ones are not only prolonged into the bark as phloem-rays, but as they pass outwards their section assumes the trumpet shape seen in those of the common Lime, the large square, parenchyma- tous cells of which they are composed being arranged in irregularly parallel, arched lines, the concavities of which face the zylem. Between each pair of these primary phloem-rays is a mass of true phloem, through which the numerous narrow secondary medullary rays are also prolonged outwards to the cortex. Longitudinal sections show the phloem to consist of much parenchyma, through which numerous elongated, thin-walled, narrow tubes pass vertically. In tangential sections these tubes are seen to follow an irregular, wavy course, reminding us of the bands of hard bast in the lime. I detect no evidence of the presence of true sieve-tubes in this phloem, though some of the numerous thin-walled tubes may represent those tissues. External to the phloem-zone are two very distinct zones of cortical parenchyma, in which we discover twin pairs of large vascular bundles passing outwards to what I presume have been foliar organs; and in the outermost cortical zone we dis- cover large, defined masses of sclerous parenchyma. ‘The plant also exhibits proofs that it also gave off true branches of larger size than mere foliar appendages. The vessels vary, from small ones with reticulated semi-scalariform walls in the young foliar(?) bundles, to others of intermediate size in the exogenous zone; whilst the latter conduct to the very much larger ones, which, intermixed with the medullary parenchyma, constitute the medullary axis of the plant. Those of the exogenous medullary regions are unquestionably vessels exhibiting modified conditions of bordered pits. The zylem, phloem, and cortical zones of this plant unquestionably suggest Gymnospermous relationships; but the structure of the centre or medullary axis has nothing analogous to it among known Gymnospermous plants, recent or fossil. It approaches much more nearly to what we find in the corresponding axis of Lepidodendron selaginoides. —- 11. The Multiplication and Vitality of certain Micro-organisms, Pathogenic and otherwise. By Purcy F. Franxianp, Ph.D., B.Sc., F.C.S. In this paper the author records a number of experiments which he has carried out on the multiplication of the micro-organisms present in natural waters, and also on the vitality of certain pathogenic organisms when purposely introduced into similar media. These phenomena haye been studied by aid of the method of gelatine-plate cultivation, originally devised by Koch. The first part of the paper treats of the influence of storage in sterilised vessels, upon the number of micro-organisms present in the unfiltered water of the rivers Thames and Lea, in the waters of these rivers after sand-filtration by the companies supplying the metropolis, and in deep- well water obtained from the chalk. Of these three different kinds of water, at the time of collection the unfiltered river-waters are the richest in micro-organisms, containing, as they do, several thousand microbes, capable of being revealed by plate-cultivation, in one cubic centimetre of water, whilst the filtered river-water have this number generally reduced by about 95 per cent., and the number present in the deep-well water rarely exceeds 10 per cubic centimetre. TRANSACTIONS OF SECTION D. 703 On storage in sterilised vessels at 20° C., however, a great change in the rela- tionship of these numbers soon takes place, for whilst the number of organisms in the crude river-water undergoes but little change or even suffers diminution, that in the filtered river-water exhibits very rapid multiplication, and this increase is even still more marked in the case of the deep-well water. The author suggests that the differences in the rate of multiplication exhibited by these three kinds of water is dependent upon the number of different varieties of micro-organisms which they contain. Thus in the unfiltered river-waters the organisms belong to a number of different kinds; the filtered river-waters exhibit fewer varieties; whilst in the deep-well water the number of varieties is still more limited, the gelatine-plates having generally the appearance of almost pure cultivations. The microbes in the deep-well water will thus be less hampered in their multiplication by hostile com- petitors than those in the filtered river-waters, and these again less than those in the crude river-waters, in which an equilibrium must have already been established between the various competitors. When the waters were exposed to a temperature of 35° C. the multiplication was in all cases very much more rapid, but both at 20° C. as well as at 35° C. the multiplication was, on prolonged storage, followed by reduction. The pathogenic forms which have been studied by the author are (1) Koch’s “ Comma’ spirilum of Asiatic cholera, (2) Finkler-Prior’s ‘ Comma’ spirillum of European cholera, and (3) the Bacillus pyocyaneus, which produces the greenish- blue colouring-matter frequently present in abscesses. The vitality of these organisms has been studied by introducing minute quantities of their cultivations into sterilised distilled water, deep-well water, tiltered Thames water, and London sewage. In these media they present some very striking differences. Thus the Bacillus pyocyaneus was found to flourish in all; even in distilled water it was present in largely multiplied numbers after fifty-three days. Koch’s ‘Comma’ spirillum, on the other hand, when introduced into deep-well water was no longer demonstrable after the ninth day, whilst in sewage it was still found in enormously multiplied numbers after twenty-nine days. Finkler-Prior’s ‘Comma’ spirillum, although showing such far greater vital activity than Koch’s in gelatine cultures, possesses far less vitality than the latter when introduced into water. Thus in the above-mentioned media it was in no case demonstrable after the first day. A curious phenomenon was observed in the case of the Bacillus pyocyaneus and Koch’s ‘ Comma’ spirillum, viz. that when introduced into water a large propor- tion of these organisms at first perish, the numbers often becoming greatly reduced, the survivors subsequently, having apparently adapted themselves to the new medium, multiplying to a greater or less extent. The author points out how necessary it is that each pathogenic organism should be made the subject of separate investigation, and how fallacious must be any generalisations concerning the vitality of pathogenic microbes which are based upon the study of a single form. s al more important results referred to above are summarised in the following table :— BACILLUS PYOCYANEUS IN DISTILLED, DEEP WELL, FILTERED THAMES WATER, AND SEWAGE. Number of Colonies obtained from 1 ce. Day of 53rd _ Pre- 2nd 3rd 5th 8th 18th 20th da paration : y Distilled { 1 6,100 203 — — — — 276 | 100,000 Water 2 6,800 368 — — — _ 13,400 69,000 Sarin (Incub.) Incub. f 9 = _ 851 87 inal p | (Incub.) | (Incub.) 6 | 262,000 — — 195,000 227,000 704 REPORT—1886. BACILLUS PYOCYANEUS, &c.—continued. Number of Colonies obtained from 1 ce. Day of aoe Pre- | 2nd 3rd 5th 8th 18th 20th | 3rd paration y Filtered if 3,900 — Innum. Thames 2 3,900 _ Innum. Water (Incub.) 1 | 29,000 _ TInnum. — Innum, | 547,000 (Incub.) (Incub.) | (Incub.) Sewage 2 | 29,000 _ 90,500 —_ Innum. Innum. 3 | 29,000 _ 116,500 -- Innum. | Innum, Kocn’s ‘ComMMA’ SPIRILLUM IN DEEP-WELL WATER, SEWAGE, AND FILTERED THAMES WATER. Number of Colonies obtained from 1 ee. Day of — Pre- 2nd 5th 6th 9th llth 17th 29th paration : 1 5,750 0 0 0 _— 0 Deep Well | (Ineub.) 2 5,750 0 0 0 — 0 3 4,750 | Innum. | Innum. | Innum. — 96,000 Sewage (Incub.) f 4,750 60,000 Innum,. | Innum, _ Innum. (20°C.) 5 456 18 1,225 _ 147 — 0 0 Deep Well (Incub.) 6 456 57 38,834 _— 1,282 — 0 0 (20°C.) ( 7 300 Innum, | Innum. — Innum, _— 128,000 56,000 Sewage ~ (Incub.) (3 . 300 19,000 Innum, _ Innum. = Innum. |Innum, Filtered { 2 — 188 0 0 0 Thames (Incub.) Water (10) — 63 313 480 173 12. The Distribution of Micro-organisms in the Air of Town, Country, and Buildings. By Purcy F. Franxuanp, Ph.D., B.Sc., F.C.S. This paper contains the results of a number of experiments which the author has made on the relative abundance of micro-organisms in the air of different places, and of the same place at different times. In these experiments the number of microbes contained in a given volume of air has been supplemented by the deter- mination of the number falling upon a unit of horizontal surface (1 sq. foot) in a unit of time (1 minute). The determinations of the number of organisms in a given volume have been made by means of the apparatus originally devised by Hesse, which consists im slowly aspirating a known volume of air through a wide glass tube coated inter- nally with sterilised nutrient gelatine. The author confirms the observations of Hesse, that, when the current of airis not too rapid, practically the whole of the or- ganisms present in the air are deposited within the first half or two-thirds of the tube. That this deposition is due to gravity alone is shown by the fact that the organisms, or rather the visible colonies which result from them, are all found upon the bottom of the tube. The organisms which, in general, exhibit least tendency to subsidence, and which are sometimes carried nearer the further extre- mity of the tube, are moulds, TRANSACTIONS OF SECTION D. 705 The number of organisms falling on a given area has been determined by expos- ing for a definite time small glass dishes filled with sterile nutrient gelatine. The greater part of the experiments have been made on the roof of the Science Schools, South Kensington, whilst comparative determinations have been made in various places both in town and country. : A number of experiments were made with a view to determining the effect of altitude upon the abundance of microbes in the air. These experiments were carried out at various stages on the dome of St. Paul’s and on the spire of Norwich Cathedral. The air in buildings has also been submitted to examination, and the fact established that, whilst in enclosed spaces in which the air is at rest the num- ber of microbes in suspension may be very small, yet when aérial disturbance is occasioned, e.g., hy persons moving about, the number is enormously increased. Some ofthe more important results are summarised in the following table :— Number of . Organisms fall- ing per square foot per minute Number of Place Organisms in ten litres of air Roof of Science Schools, South Kensington (average) : F ; : ; 35 279 Country Places (average) . : 2 3 J 14 79 Open Places in London (Kensington Gardens, Hyde Park, Primrose Hill) (average) ? 2 24 85 Golden Gallery . : ‘ : 11 115 St. Paul’s -{Stone Gallery . - : : 34 125 Churchyard : : : ; 70 188 Spire (300 feet) : “ a 49 Norwich Cathedral .4{ Tower (180 feet - : 9 107 Close : , . 18 354 Kensington Museum (Friday) ; - r : 18 20 Ditto (Saturday) free day . : : C : 73 87 Natural History Museum (morning) . - * 50 136 Ditto (afternoon) (number of visitors more numerous) . . . : : : ; - 70 255 Railway Carriage, four passengers, window open . _— 395 Ditto, ten passengers, window almost closed F — 3,120 Ward in Brompton Hospital for Consumption (8 beds) morning: ‘ . ; ? ; : 43 11 Ditto, afternoon . 2 ; , : " F 130 130 Ditto, night . ; : ‘ : ; 4 : 42 44 — — SEE ee ee eae See | The figures given in the above table show that the air on the roof of the Science Schools is very considerably richer in micro-organisms than that collected in the London parks, and this again than that of the country. The gradual attenuation of the microbes in ascending St. Paul’s and the spire of Norwich Cathedral is also very striking. The figures obtained in the museums, railway carriage, and Hospital for Consumption speak for themselves, and show how in confined spaces the number of micro-organisms present in the air is influenced by the number of persons moving about. ; 1886. ZZ 706 REPORT—1886. 13. Note on the Floral Symmetry of the Genus Cypripedium. By Dr. Maxwrtt T. Masters, F.R.S. In this note the author adverted to so much of the normal structure of Orchids in general, and of Cypripedium in particular, as is necessary for the elucidation of his subject, and proceeded to describe a case of regular peloria in Cypripedium caudatum, which shows a reversion to the typical form of Orchids, and goes to prove that the so-called genus Uropedium was only a pelorian form of Cypripedium. The construction of the androecium in these plants is then alluded to, and illustrations given of all intermediate stages from monandry to hexandry, The frequently observed tendencies to a dimerous condition, and to the develop- ment of the inner row of stamens, was alluded to, and the significance of these changes pointed out. The morphological changes consequent upon hybridisation, and the inferences to be derived from them, were passed under review. The paper concluded with a general summary of the teratological changes observed in the tribe Cypripediez. 14. On the Culture of usually aerobic Bacteria under anaerobic conditions. By Professor Marcus M. Hartoe and Atuan P. Swan. Bacillus subtilis, regarded as a most typically aerobic bacterium, will germinate in appropriate nutritive solutions, form its ‘ Kahmhaut’ and spores, when oxygen is excluded from the space not occupied by the liquid and replaced by carbon dioxide. Under these circumstances pressure rises in the closed apparatus employed, and bubbles of CO, raise the Kahmhaut in parts, leading to the inference that the vital energy of B. subtilis is, under these conditions, derived from true fermentation, not oxidation, The lactic organismn of Pasteur, usually aerobic, will develope and grow in suitable solutions during or after alcoholic fermentation induced by Saccharomyces, as in Kephir and other forms of Koumiss, and after the oxygen must be used up and replaced by carbon dioxide. 15. On Cortical Fibrovascular Bundles in some species of Lecythidese and Barringtonies. By Professor Marcus M. Harroa. Accessory fibrovascular bundles are usually connected with abnormalities of vegetation ; and probably serve chiefly to assure continuity of the phloem under pressure ; hence it is interesting to note their occurrence where this explanation is inadmissible. In Gustavia and Lecythis, belonging to the sub-order Lecythidex of Myrtacex, there is a complete system of cortical bundles, external to the pericycle, anastomosing with the leaf-tracks at the nodes. These bundles have often a com- plete circle of exogenous wood, without pith, and a crescent of phloem on the outer side; they are all but concentric; in the petiole it is impossible to distinguish the bundles belonging to the common bundles from the cortical set, owing to the anas- tomoses in the nodes. The section of the petiole with its scattered bundles recalls that of a monocotyledonous stem, but there is no pericycle. In Stravadium racemosum, belonging to the closely allied Barringtoniee, there are similar bundles, but the orientation of the liber is reversed, and the common bundle retains its distinctness in the petiole. The explanation seems suggested by the following facts. The cataphyllary first leaves of the seedlings of Gustavia are decurrent to the node below, so that the stem is winged and the wings contain one or two pairs of accessory common bundles. Higher up the wings are lost, but their vascular bundles remain to give rise to this system of accessory bundles. Napoleona has a similar system of cortical bundles. TRANSACTIONS OF SECTION D. 707 16. On the Growing Point of Phanerogams.' By Percy Groom. These investigations were undertaken to test the accuracy of those of Dingler and Korschelt, who had found that phanerogams grow by means of a single apical cell. The author investigated many rapidly growing buds, and invariably found no apical cell, but an apical meristem. In Gymnosperms a companion type is a growing point in which there is no distinct dermatogen, periblem, or plerome. In Angiosperms there is invariably a distinct and regular dermatogen, which covers tissue the fate of which the author did not follow out, but which in some cases appeared to be only indistinctly, if at all, differentiated into periblem and plerome. ‘The author finally endeavoured to trace roughly the evolution of the growing point from the typical vascular Cryptogam, with one apical cell, to the Angiosperm, with a distinct dermatogen. He regards the Gymnosperms as intermediate types. 17. On the Cultivation of Fern prothallia for Laboratory purposes. By J. Morey. In botanical studies it is now the custom to examine fully the life-history of specially selected plants, and as far as possible to cultivate them under conditions in which they can be at all times available for examination. It may not be un- interesting to teaching botanists therefore to bring together the ways in which the spores.of ferns can be grown, or at least such ways as are applicable to the laboratory. Amongst British ferns spores of Osmunda and Lastrea Filix-mas are the most easy to grow, rather less easy Polystichums and Athyriums; the most difficult I have found to be Blechnum and Polypodium. If ferns are to be grown from spores, the spores must be obtained in a condition fit for growing. If the sori are examined by the aid of a magnifying-glass and the sporangia are found to be of a dark-brown colour, and some of them have already split, a frond or part of a frond should be wrapped in unglazed paper and kept in a dry place until required. If any one of the pinnz or the apex of any one of the fronds is forked or in any way abnormal, the spores obtained from those parts of the fronds will very likely reproduce the abnormality on every frond of some of the young plants. I generally grow them in a 12-inch fern-pan covered with a round, flat-topped glass (confectioner’s cake-glass). This pan will hold eight tree-pots, called sixties, seven round the edge and one in the centre: the pots are prepared for the reception of the spores in the following way: first a quantity of waste pots, bricks, or sand- stone are broken up into different sized pieces from three-quarters of an inch to a quarter ; with these the pots are filled to within one inch of the top, beginning with the largest pieces and finishing off with the smallest ; this ensures perfect drainage, and at the same time prevents the soil from being washed down amongst the crocks. The pots with the drainage should now be placed in a vessel and covered with boiling water; this will kill all germs of animal or vegetable life that may be adhering to them. Next pass some cocoa-fibre refuse through a riddle with a quarter-inch mesh, and add one-third silver sand. This also must be covered with boiling water, and after the water is poured off the sand and fibre must be well mixed. .For spores of the strong-growing ferns, such as the Lastreas, Polystichums, ‘Osmundas, &c., the pots must be nearly filled, rather firmly, with the mixture; but for wall or rock ferns, such as the Aspleniums, Woodsias, Cystopteris, &c., merely sprinkle on about a quarter of an inch thick, and for these it will be better to fill up the pots with drainage nearer to the top. They are now ready to receive the spores, which can be sown by first unwrapping the paper in which the fronds have been placed to dry, when it will be found to contain thousands of dark-brown dust-like ‘spores far too numerous for sowing. To obviate this the paper should be held at an angle of about 45° and gently shaken over another piece of paper, when all the super- 1 Berichte d. deutschen bot. Gesellschaft, Bd. III. zZZ2 708 rREPORT—1886. fluous spores will roll off, still leaving hundreds in the interstices of the first unglazed paper. This should now be turned over on to the top of a pot, and rapped two or three times with the end of a lead-pencil or the thumb-nail, when the spores will be shaken off on to the fibre. The pot is now ready to be placed in the pan, and when all the others have been prepared in the same way with the same or different kinds of spores, the pan can be placed on a level shelf in a window facing the south, and water that has been boiled poured in to the depth of half an inch; if the pots contain spores of rock ferns only a quarter of an inch will do, but if there are pots in the same pan some of which contain spores of the strong-growing kinds, and some of the rock-growing kinds, place the pots containing the latter on pieces of slate. This will prevent them from getting too wet. If the cover-glass is now put on, all that will be required for the next three weeks or a month will be to place a sheet of tissue paper before the glass during the midday sun, and if the bottom of the pan becomes dry by evaporation add more water; the water need not be boiled after the spores have germinated. After the spores have been sown from six to twelve days, if the weather should be warm and bright, each pot can be examined with a magnifying-glass, and in those containing spores of Osmunda, or Lastrea Filix-mas, hundreds of small green specks will probably be seen, which from day to day will increase in size until they meet and cover the surface with green leaf-like prothalli. If they come in contact before each one has attained at least a quarter of an inch in diameter the spores have been too thickly sewn and must be thinned out. Fronds will soon begin to appear, and will increase in number and size, each successive frond larger and perhaps more complex than its predecessor. Sometimes a fungus attacks the prothalli in a pot. It first appears as a dark spot, and gradually spreads until they are all destroyed. If seen in time it can be stopped by heating some sand in an iron spoon and pouring some on the part affected, but should the fungus pass through the soil and kill all the prothalli there may still be some spores left that were unable to germinate in the first instance on account of being too thickly sown; these will soon make their appearance, and the fungus will not attack the pot a second time. At any time in their development the prothalli can be lifted for examination, for this purpose preference being given to a fine ivory paper-knife. The necessary conditions for the growth of spores are light and heat without direct sunshine, moisture without stagnation, and the absence of competition from plants of a stronger growth; provided these conditions be present, ferns and other spores can be grown in various ways for laboratory purposes. They can be grown ona thin piece of sandstone, a piece of slate, a lump of peat, or a piece of glass. 18. Life Cycles of Organisms represented diagrammatically and comparatively. By D. McAtprne. 19. A Re-arrangement of the Divisions of Biology. By D. McAuprnt. Sus-Szction ANIMAL MORPHOLOGY. 1. On the Theory of Sex, Heredity, and Reproduction. By Patrick GEDDES. In dealing with a subject naturally so obscure and so confused by conflicting hypotheses as that of the nature and origin of sex, it is necessary to start with a clear understanding that the required explanation must be not only in terms of structure but of function, and must be satisfactory from the point of view of each school of morphologists and physiologists in turn. Thus in any organism we must not only note the general outward characters which may distinguish the sexes, and correlate these with their habits of life, but follow them into the structures and functions of the internal organs, and thence through the tissues to the egg-cells and sperm-cells which respectively characterise the male and female. Below this, however, a new problem arises; it does not suffice to observe these characteristic: TRANSACTIONS OF SECTION D. 709 forms; they need explanation in terms of the structural, and yet more of the functional, properties of protoplasm itself. Were this once done, it would actually be possible to retrace the progress of the science, and in the same way interpret, in terms of the functions of protoplasm, the forms and functions of tissues and organs—nay, even the facts of aspect, habit, and temperament themselves—thus reaching the rationale of what, had hitherto been matter of empirical observation only. The functions of protoplasm are essentially two: first that of constructive or synthetic change or metabolism (assimilation or anabolism), contrasted with that of destructive or analytic change (disassimilation or katabolism), and these two sets of changes never absolutely balance, as all the phenomena of rest and motion, growth and diminution, nutrition and reproduction clearly show. During life neither process can completely stop, but their algebraic sum varies within wide limits. Starting from the undifferentiated amoeboid cell, a surplus of anabolism over katabolism involves not only a growth in size, but a gain in potential energy, and a reduction of kinetic, t.e., a diminution of movement. Irregularities thus tend to disappear; surface-tension, too, may aid; and the cell acquires a spheroidal form. Again, starting from the amceboid cell, if the katabolic tendency be in excess, the increasing liberation of kinetic energy thus implied must be expressed in increased activity with diminished size. The form of the ovum and spermatozoon are thus explained as the outcome of protoplasmic activities of a respectively pre- ponderating constructive and destructive kind. This conception of sex at once leads to the hoped-for abundance of interpre- tation ; thus the gradual differentiation of the two sexes becomes intelligible, since necessitated by the accumulation of one or other of these two great tendencies with advancing age, and (passing over the endless application of the theory to such problems as those of the alternation of generations, hermaphroditism, partheno- genesis, &c.), it affords us an explanation of the differences and habits, and even of the determination of the sexes in plants and animals. Thus the degenerate male rotifer is no mere exceptional curiosity, but the extreme development of a tendency visible everywhere, for (save among those higher animals where the strain of reproduction on the female necessitates the doubled activity of the male), females tend on the average to show better growth or larger size. In plants or tadpoles alike the determination of sex has been shown to be effected by nutrition, and to be female when this is abundant, male when it is checked. The phenomena of sex, then, are no isolated ones, but express the highest outcome of the whole activities of the organism—the literal blossoming of the individual life. The preceding argument will also be found somewhat more fully in the writer's article on Sex in the ‘ Encyclopzedia Britannica,’ and in extended form in a paper of similar title to the present in the ‘Proceedings of the Royal Society of Edin- burgh,’ 1886. 2. Notes on Australian Celenterates. By Dr. R. Von LENDENFELD. The author describes the extraordinary mode of development of Phyllorhiza punctata,a rhizostomous Medusa discovered by him in Port Jackson. The Ephyra has eight, the next stage twenty-four, the next sixteen, and the adult again eight marginal bodies. If the umbrella margin is injured and newly formed, marginal ‘bodies appear between ail the newly formed flaps. Further, the migrations of Crambessa mosaica at the breeding time are described, ‘This and other species of that genus of rhizostomous Meduse migrate far up the rivers, like the salmon, to deposit their young. A remarkable change in the colour of Crambessa mosaica which has taken place in Port Jackson since the observations of Huxley about forty years ago, is ‘described. A new variety, which is brown, seems to have been produced or to have immigrated and superseded the blue form, which was observed by Huxley and others in that locality. In Port Phillip the blue variety is still exclusively found. The author has found, in examining the lower freshwater animals, that the freshwater Hydroids and Sponges, as also the freshwater Rhizopoda of Australia, 710 REPORT—1886. are very similar to the European, whilst the marine species of these groups differ very much in the two localities, He concludes that these freshwater forms are very old and conservative, and may be supposed to be the unchanged offspring of old. ancestral forms, as such possessing particular systematic importance. 3. On a Sponge possessing Tetragonal Symmetry, with Observations on the Minute Structure of the Tetractinellide. By Professor Sottas, LL.D. 4, The Anatomy of Newra. By Professor Happon. 5. The Nervous System of Sponges. By Dr. R. Von LENDENFELD. The author gives an account of his discoveries on this subject up to date. Sensitive and ganglia cells have been observed by him in a number of sponges. Their locality varies, their shape is constant. They are mesodermal, and appear to preside over the moyements of the membranes and pore-sieves, and so regulate the water-curent. The great difference between sponges and higher ccelenterates is, that in the former the most important organs are mesodermal, whilst in the latter they are ecto- or ento-dermal. He divides the type Ocelenterata accordingly into Coelenterata mesodermalia, or sponges, and Coelenterata epithelaria or Cnidaria, as: sub-types. 6. The Function of Nettle-cells. By Dr. R. Von LENDENFELD. The author gives a detailed account of the structure of the nettle-cells, or cnidoblasts, and discusses some biological facts regarding their function. He: comes to the conclusion that the nettle-cells are exploded by direct reflex action when the cnidocil is touched ; but that the animal can counteract this reflex action by a centrifugally acting nervous irritation, in the same way as reflex actions are. controlled by higher nervous centres in man. 7. Note on a peculiar Medusa from St. Andrew’s Bay. By Professor McIntosu, M.D., DL.D., £.R.S. When using the large net (with the fine mesh) attached to the triangle of wood,. as described in the Report of the Marine Laboratory, presented to the Association, one of the earliest sweeps (August 9), north of the pier at the depth of 3 fathoms,. in 5 fathoms’ water, brought in a Medusa hitherto unknown to me. It occurred amidst swarms of Thawmantias, Bougainvillea, Oceania, Turris, Cyanea, Aurelia, Pleurobrachia and Beroé, but was readily distinguished by the presence of a simple pale cross on the translucent hyaline disc. The same form was again met with about a fortnight later off the East Rocks. It is of considerable size, its dise measuring about five inches in diameter. It has the ordinary shape, viz., moderately convex dorsally, somewhat flattened ventrally, and presents no novelty in the microscopic structure of its hyaline tissue. The margin is surrounded by a closely arranged series of tentacles of considerable length. These taper from base to apex, each moreover having a single small black pigment-speck at the base. The latter shows no special differentiation, only a group of simple pigment-granules. Within the bases of the tentacles is a narrow frilled membrane, apparently the yelum, and this is especially distinct during the contractions of the disc. The reproductive bands begin a short distance within the margin, and extend along the representatives of the radiating tubes right across the disc in each case,. thus forming a conspicuous cross. These bands are somewhat regularly folded or lobulated at the margin, and have a pale grey or dull whitish colour. The elements do not seem to be much developed, the minute cells which distend the. irills being finely granular, TRANSACTIONS OF SECTION D. 711 The reproductive bands join each other in the middle of the disc, which presents no trace of a mouth or of a manubrium, and in this respect it differs from any ordinary form. It is premature to speak decisively as to the precise nature of the form, which has certain resemblances to an abnormal example of Forbes’s Thawmantias melanops, from Shetland. The latter, however, was only half an inch in diameter, and had the usual manubrium. 8. Note on Helopeltis Antonii, Sign., in Ceylon. By Henry Trimen, M.B., PLS. I have brought for exhibition some specimens of this species of plant-bug, in consequence of its having attracted a good deal of attention in the East, as a pest of tropical agriculture, and also because there has been some confusion as to its identification. Two or three years ago some of the growers of cacao (Theobroma Cacao) in Ceylon became alarmed at the prevalence of a ‘disease’ in their trees affecting especially the young twigs and young fruits; the former were spotted, then began to shrivel, and finally died off, and the latter became black and dry, and failed to arrive at maturity. At the request of the Government of the Colony I made an investigation of, and reported upon, this state of things, and satisfied myself that the main cause of the damage to the trees was due to the effects of the punctures and suction of the juices effected by the insect now shown. As I am, however, not enough of an entomologist to be acquainted with the insects of Ceylon specifically, I should have been unable to determine the present one further than to refer it to its group, had I not possessed specimens from Java of the bug there identified as Helopeltis Antoni, with which our insect apparently agreed. In Java this insect has been very destructive to the cinchona plantations, affecting the young shoots of the trees in a very similar way to that noticed in cacao in Ceylon; and it was always a matter of surprise to me that our cinchona was not attacked also. Since my visit to England I have had the advantage of submitting specimens of the Ceylon insect to Mr. Waterhouse, of the British Museum. The collection there, though it possessed specimens of the Java Helopeltis, had not any from Ceylon; and the result of comparison has convinced Mr, Waterhouse that the two are not identical. The Ceylon insect agrees completely with Signoret’s original description of H. Antonii, which was made (in 1858) from Ceylon specimens ; whilst the Java insect, which has hitherto passed under the same name, differs in seyeral particulars, and is, perhaps, undescribed.’ There remains another closely-allied Helopeltis which is most destructive to the tea-plantations in Assam, where it is known under the name of ‘ Mosquito-blight.’ This has been named Z. theivora, and has recently formed the subject of an illus- trated memoir by Mr. Wood-Mason, of Calcutta. I had hitherto supposed that this also was identical with the H. Antoni of Ceylon, but the tea-plants there have scarcely been touched (if at all) by that insect, and in view of the above facts with regard to the Java Helopeltis, it is quite possible that the Assam one may also be a distinct species and restricted to different plants. It is remarkable that species of one genus of Heteropterous insects should he serious pests to three of the most important products of planters in the East. 9. On Marsupial Bones. By Professor THompson. 10. On the Sense of Smell. By Professor Harorart, 11. On Young Cod, Sc. By Professor McInrosx, M.D., LL.D., F.R.S. 1 This has, since the above note was read, been ‘figured and described by Mr, Waterhouse as H. Bradyi (Trans. Ent. Soc. Lond. 1886, p. 458). 712 REPORT— 1886. Section E.—GEOGRAPHY. PRESIDENT OF THE SECTION—Major-General Sir F. J, Gotpsmip, K.C.S.L., C.B., F.R.G.S. THURSDAY, SEPTEMBER 2. The PrusitvEntT delivered the following Address :— However diffident I may feel] in undertaking the duties of President of the very im- portant Section of Geography at this anniversary, I have no right to take shelter under that diffidence for any shortcoming in the fulfilment of my task. All I would seek at your hands is indulgence for one whose training and antecedents have scarcely fitted him for appearing before you in a quasi-professorial capacity, and whose brief tenure of a Presidential chair at a meeting such as this must be regarded as rather an incidental passage in the annals of the British Association than a fair illustration of its modus operandi, or principle of selection in respect to its officers. As to the subject of my opening address, I know none more befitting the occa- sion than the means of popularising the branch of science to which the meetings in this Section will be devoted, and thus attracting towards it that attention which it merits—nay which, in this our country if anywhere, it demands and necessi- tates. The question is a wide one, but I will endeavour to narrow the field of its dis- cussion to suit our purpose of to-day, and keep within reasonable limits. A few words will suffice to lay before you the programme. It embraces: first, the uses of geography, an exposition of which should prove, and a due apprehension of which should admit, the necessity of its inclusion among the special studies of public schools ; secondly, the mode of imparting a knowledge of geography so as to render it at once practical and engaging; and finally, such illustrations of modern travel and research as may serve to demonstrate how urgent is the study of geography to all classes in this country, Before closing the subject, I shall endeavour to draw your attention directly, if somewhat cursorily, to the progress made by travellers and geographers in further- ing what I may for the nonce describe as the objects of their profession during the past year, or since the last Annual Meeting of the British Association at Aberdeen. ut I shall only dwell upon such instances of geographical progress as from their character and locality come within the range of my personal experience, and serve to illustrate the main argument of this address. To begin then with the uses of geography. There are doubtless many who will say demonstration here is superfluous, and that if its use was not admitted it would find no place in school studies, which is contrary to fact in many instances ; there would be no primers or elementary works on the subject, whereas they may be reckoned by the score ; books of travel would be rather entertaining than in- area a charge which many recently published volumes would disprove; and so forth. . _, Some again will argue that its uses, such as they are, must be restricted to the few specialists who aspire to be geographers, and that for the million it is enough TRANSACTIONS OF SECTION E. 713 to carry about a rough idea of the four quarters of the globe, the principal countries and capitals in them, and a sufficient amount of preliminary instruction to under- stand Bradshaw and Baedeker. A third, and perhaps the largest category among educated ‘people, consists of those who are indifferent to the whole question, and are content to find in geography either an honoured branch of science, or a mere nominal study, according to the views of the latest speaker, or most plausible reasoner. If it be allowable to apply things holy to things profane, no truer illus- tration of this class can be given than the Scriptural definition of men who receive seed ‘in stony places.’ To the first of the above I would say that the place which geography holds among school studies is not that which it ought to hold if its uses were understood and appreciated. Primers and elementary books already published are good enough in their way, but the instruction they contain is not seriously imparted ; and it may be that something fitter and more attractive to the beginner could be produced, At present all school-books on geography may be said, as a rule, to be consigned to the shelf of secondary subjects; and this is not the treatment which should be reserved for a study of such real magnitude. By-and-by it will be my endeavour to establish by argument and example the indisputable character of its importance, For those who look upon geography as a profession which needs rather separate training than general education, and would prefer to leave its acquirement to travellers aiming at distinction, specialists in Government employ, and the more zealous and scientific Fellows of the Royal or any other geographical society, I can only express my regret that the delusion under which they lie unfits them so thoroughly to understand and much less satisfy the wants of a rising generation. By denying the universal character of the study they clearly misapprehend its true scope, and are dwarfing it to within the narrow limits of a conventional school task, As a matter of State or public school education the science of geography should in truth be elevated, not degraded. In my humble opinion it should be placed on @ par with classics, mathematics, and history, with each and all of which it has affinity. Undoubtedly there are accomplishments which come, as it were, of them- selves, or are the outcome of lightly-sown seeds in the home. These for the most part are rather mechanical than mental, though some may have advocates to claim for them intellectual honour, Buta knowledge of geography is not to be so acquired : it will not come like handwriting with incidental practice, nor is it to be gained by mere travelling. To move from place to place, whether across seas or conti- nents, or both, to go round the globe itself and visit every important country and capital in the track chosen, even to prefer byways to railways and search into obscure and hidden spots rather than those which are more generally frequented— all this process affords admirable matter for the note-book of the man of the world and observer, but will not educate in geography, unless the student himself has a serious purpose to turn his wanderings to the account of science. The cursory description which would apply to men and women, cattle and conveyances, hotels and caravansaries, restaurants, coffee-houses, and the like, in a moving panorama, is not always suited to bring out in bold relief the physical aspects of a country. To the indifferent and wavering, to those who would wish to promote the study of geography if they could feel persuaded that it needs promotion, but who would leave to the better judgment atid experience of others the decision on the whole question ; to those who are content to accept the institution of a professorial chair in honour to the science, or to leave geographical study to the primitive teaching of their own childhood, whichever course be most in accordance with the temper or fashion of the times—I can perhaps do no better than appeal on the erounds of urgency—in other words, of the real importance of the cause for which, in common with abler and worthier advocates, I would now most earnestly plead. The open- ing verse of the Bible, in imparting to us the first great act of creation, at once establishes the high position, among the lessons to be taught mankind, of astronomy and geography ; and the description of the garden of Eden, and the river dividing into four heads—two of which, the Hiddekel and the Euphrates, still mingle their waters in one, after a long separate course from the highlands of Armenia—is an 714 REPORT—1886. illustration of pure geography conspicuous in the second chapter, immediately following the story of man’s formation. To say that there is a special fascination in Biblical research, whether geographical or archzeological, is to say what those alone know who haye made such studies a labour of love as well as a part of duty. But those who do know this truth from experience are ready to assert it without reservation. I have myself heard the assertion from the lips of one of the most zealous and industrious contributors to Smith’s ‘ Dictionary of the Bible ’—one whose versatile talent and comprehensive intelligence have now culled him to a different sphere of usefulness, but who is no less a sure and competent witness, And is there no fascination in contemplating the marvellous fact I have just cited ? For assuredly it 7s a marvel that for nearly 6,000 years, or, so far as we can tell, from the creation of the world itself in which we live, and the bestowal of names upon things animate and inanimate up to the present day, we find two ancient rivers retaining their names unchanged—Euphrates and Hiddekel. There is no need to speculate here on the Aryan origin attributed to the first, nor upon any broader meaning implied by the latter. I can myself answer for the local name “Farat’ or ‘Al-farat,) and ‘Digla’ or ‘Dagla’ (with the article, Al-dagla, Addagal, Addigal) in use between Baghdad and the Persian Gulf. In touching upon Biblical research, I may be told that—according to hard thinkers at the present hour—I am taking a sentimental view of an argument which should be mainly practical. But the geography of Mesopotamia, as of Palestine, is to all intents and purposes a practical study, especially in these days of possible railways and new lines of intercommunication east and west; now, too, that Cyprus is ours, and the immense advantages of its occupation have been demonstrated by time and experience. Moreover, if any geography can be con- sidered Biblical, it is that of Asiatic Turkey, both as regards the New Testament and the Old. I am not, however, going to dwell upon this highest view of the subject. The connection of geography with Holy Writ is self-evident, and the twenty-one years’ history of the Palestine Exploration Fund, only just written, affords an admirable instance how public interest may be aroused to support, and individual energy and. intelligence may be exercised to prosecute, a work hallowed by association. Those: who were present at this year’s meeting at the Royal Institution will not soon forget the cordial manner in which the names of the foremost labourers in this area. of usefulness were received by the crowded audience. And rightly so. They have been worthy labourers in a worthy cause, and merit the grateful honour of public recognition and approval. Turning to secular things, I almost seem to be treading upon the threshold of platitudes when seeking to explain why geography should be useful to young mem of ordinary culture, for whatever career they may be destined. In some cases it is naturally more urgent as a study than in others. The military man, for exam- ple, should be more or less a scientific geographer. His profession may require: him to survey and describe new regions; and a campaign over a beaten track should find him acquainted with the minute topography and physical aspect of places, at least the names of which are familiar household words. The sailor should in like manner bear in mind the configuration and character of sea-coasts and carry about the landmarks of his own observation as well as those to which he may refer in books. To both must geography be eminently a professional study. But, considering the enormous extent of our Indian Empire and Colonies, and the many foreign States with which we must have intimate relations, is any Englishman, I would ask, competent to discuss, much less to serve, the interests of his country who knows nothing of the physical features, resources, products, popu- lation, and statistics of these? It seems to me to be the duty of every loyal sub- ject and citizen, high or low, rich or poor, to seek information on these heads: wherever it may be obtained. But of all men who should realise geography in its broad, comprehensive sense —hboth as an aid to history, and as a science to which history may be subordinate— first in order is the statesman in whose province falls the disposal and partitioning of countries or regions, "What should we say of the judge—we may be thankful TRANSACTIONS OF SECTION E. 715- there are none such on the English bench—who not only gave his decision without mastering the merits of the case before him, but who was also ignorant of the law and precedents which should guide him in the treatment of those merits? The argument might apply with equal force to other callings from the members of° which professional opinions or decrees are required by their fellow-men. Why, the evil would be so great and so palpable that its existence would not be tole- rated for a single day: and the only reason why it zs allowed to prevail in matters - geographical is that, though equally great in respect of these, it is not equally palpable. The statesman may not know the situation of this or that particular place, nor its products and resources, but neither does the public. One is not. taught geography any more than the other; so that while ignorance and error are brought to bear on a spurious judgment, the critic is not in a position to point out the real flaw, and the blunderer escapes the scathing condemnation which would otherwise await him in the columns of the morning paper. Let us suppose a case by way of illustration—a case which conveys no exagge-- tated idea of what happens, or may happen in the course of a year—a case which without being an actual occurrence has in it the flavour of actual occurrences. There is a large tract of land in the far West or far East, it matters not which. All that is known about it is that it is called Laputa or Barataria, and that it is situated in the central part of a region or continent so vast that it might be reason- ably called the largest quarter of the globe. Well: it is encroached upon by a powerful neighbour, and England requires the preservation of that land’s integrity and independence. Her best instructors on the matter have told her that such is her interest, and she believes them. Intervention, therefore, becomes necessary ; negotiations ensue ; and the whole question resolves itself into a partition of terri-- tory and demarcation of boundary—in other words, the question becomes one of geography—what I should call, fur reasons to be explained hereafter—Political Geography. Who, if not the ruling statesman, should know the true principle on which to deal with a large settlement of this nature—one, it may be, involving ethnological, commercial, humanitarian quite as much as territorial considerations ? Who, if not the agent on the spot, should know the details to regulate the applica- tion of the principle ? But the statesman should be in full possession of his agent’s details, and be capable of appreciating them not only from the latest reports- supplied, but from a certain insight into the matter obtained from early study.. He should have been coached in that comprehensive kind of geography which would have embraced the particular information required. Under present arrange- ments it is not so. The geography taught at schools is too simple or too scientific —too complex or too superficial ; in any case it is not the geography which would benefit the cabinet minister in solving a territorial difficulty any more than would those ‘ingenuz artes’ which have so strong a civilising influence on the natural man. Experience in classics may forestall the faulty quotation and false quantity,. but fail to suspend the false move on the political board. And it need not be said that, while the first, in point of fact, affects the speaker only, the last concerns. the happiness of the million. We now reach the second consideration: the mode of imparting a knowledge of geography so as to render it at once practical and engaging; and I may be pardoned if I dwell upon this somewhat lengthily, for it involves the gist of the whole question before us. It is always easier to detect a flaw than to finda remedy, and in the present case the flaw is generally admitted by experts. There may be differences of opinion on its character and extent, but apparently there are none on its existence. [ shall have to recur to the first, but would ask leave to dismiss the last as established. We are told on excellent authority that in our own country the elements of success in geography are wanting, and the conclusion has been practically accepted by the representative Society for this branch of Imowledge. The remedy has been suggested, and in a certain sense partially applied, but a great deal more remains to be done, and the many views entertained. and expressed by competent men on the claims and requirements of geography in England render necessary a short review of what may be called the ‘ situation,” including notice of work achieved in the direction of reform. 716 | REPORT—1886. In the first place let us examine into the work done and doing by the Royal Geographical Society. What the objects of this Society are, and what have been its operations for half a century, may be gathered by a perusal of Mr. Clements Markham’s interesting record published on the occasion of its completing the fiftieth year of its existence on July 16, 1880. I quote two passages which bear upon our present lines of thought. One recites the propositions, ‘ unanimously accepted as sound and true,’ which are in truth the basis on which this now flourishing institution was originally formed. They are thus expressed : ‘That a Society was needed whose sole object should be the promotion and diffusion of that most important and entertaining branch of knowledge, geography ; and that a useful Society might therefore be formed under the name of the GEOGRAPHICAL Society or Lonpon; that the interest excited by this depart- ment of science is universally felt, that its advantages are of the first importance to mankind in general, and paramount to the welfare of a maritime nation like Great Britain, with its numerous and extensive foreign possessions; that its decided utility in conferring just and distinct notions of the physical and political relations of our globe must be obvious to everyone, and is the more enhanced by this species of knowledge being obtainable without much difficulty, while at the same time it affords a copious source of rational amusement, and finally that, although there is a vast store of geographical information existing in Great Britain, yet it is so scattered and dispersed, either in large books that are not generally accessible, or in the bureaus of public departments, or in the possession of private individuals, as to be nearly unavailable to the public.’ There is perhaps a quaint boldness discernible in coupling the adjectives ‘important and entertaining, and introducing the word ‘ amusement,’ but these verbal expressions are unquestionably appropriate, and may suggest an explanation of much of the Society’s popularity at the present time—a popularity exemplified in the large and increasing number of its fellows. The second passage from Mr. Markham’s report is the author’s own estimate of geographical work—an estimate supported by a wide and varied personal ex- perience :— ‘Geography is a progressive science. Every year, with its discoveries and novelties, also brings forth a large crop of corrections and of information which modifies preconceived theories and opinions. It is this freshness, this constant sup- ply of new material, which constitutes one of the many charms of geographical research,’ Let us add a hope that when its real scope becomes known and its uses more patent to our masters in education, efficient advocates will not be wanting to secure its acknowledgment in England as a study of absolute necessity. Of late years the Royal Geographical Society, in pursuance of its originally ex- pressed aims and objects, and strong in the experience of a long and prosperous career, has endeavoured to arouse the rising generation to a sense of their short— comings as regards the particular science in the promotion of which it has its own raison détre. It granted prizes to such public schools as chose to compete for them, and after sixteen years’ trial discontinued the grant, owing to unsatisfactory results. It opened correspondence with schools and colleges, and made other judicious and laudable attempts to evoke sympathy and support. But all its pro- ceedings have been as it were preliminary, and may be considered rather as foun- dation-stones of a temple of success than the outer walls or any visible part of the building itself. A more recent attempt to reach the masses was the Exhibition of Educational Appliances. Objects used in geographical instruction at home and abroad were collected and arranged in galleries hired for the occasion, and the public were invited to inspect them. At the same time appropriate lectures were periodically delivered, by competent and experienced men, to the visitors, many of whom were not merely interested amateurs, but persons actually engaged in school teaching. Attention was called to the fact that the exhibition was purely educa- tional; that there were in it specimens of German, Austrian, and Swiss maps, executed with a finish and detail unusual in ourschool maps at home; but that as the Society’s inquiry embraced universities as well as schools, part of the appliances TRANSACTIONS OF SECTION E. TLT exhibited were used in Continental universities, though in reality some of the finest maps shown were found also in the higher schools of Germany and Austria.’ Besides maps, there were in the collection globes, models, and text-books, the pre- sentations not being confined to countries visited by the inspector, to whom the task of collection had been entrusted, but from others also; and these were further supplemented by contributions from British publishers. The result of this new departure—if the term be allowable—was pronounced very satisfactory, and at the close of the exhibition, or in the spring of the present year, the council considered what would be the next best step to take in furtherance of their desire to raise the character of geographical study. At a later date, on the recommendation of their Educational Committee, they resolved on addressing the universities to the effect that chairs or readerships be instituted similar to those which were at that time filled in Germany by Carl Ritter at Berlin and Professor Peschel and Richthofen at Leipsic. In carrying out the resolution alternative schemes were submitted. The council would appoint, under approval of the uni- versity authorities, a lecturer or reader in geography, paid out of the Society’s funds, he being accorded a fitting local status; or each university might join with the council in the matter of payment, and a reader be appointed by a committee in which the Society should be represented. Thus far I have referred to the proceedings of the Royal Geographical Society, and I think you will allow to those responsible for them the credit of moving in the right direction, with a genuine desire to promote a good cause. But the new Geographical Societies have not been idle: Edinburgh and Manchester have shown an intelligent vigour in seeking to popularise the study of geography, and much has been done in both places within the past few months only, which is worthy of permanent record. Of Manchester I can speak with a certain amount of personal knowledge, having read two papers there, and had the advantage of making the acquaintance of the more prominent members of the Society. The movement in a great commercial city such as this may well aid in strengthening the hands of the London Society ; for nothing could more faithfully demonstrate the practical uses of the science under consideration than the fact that it had a centre in Manchester. As to the nature of the recent work there, I need refer only to the Exhibition of Geographical Appliances which followed that in London —arranged by the mayor at an art gallery lent for the purpose. We are told in the published reports that space could not be found for showing all the specimens sent, but that a selection was made, and that maps were the main feature. These were of many countries—English, German, Dutch, French, Italian, Norwegian, Swedish, Russian, American, and Canadian—among the Norwegian being a fine series presented to the Manchester Society by the Royal Institute of Christiania. During the exhibition, seventeen addresses were delivered in the building on subjects connected with geographical education. Every day lectures were given of about three-quarters of an hour each, on the contents of the rooms, to audiences ranging from ten to a hundred and fifty persons. The special Education Committee, appointed with reference to the Exhibition of Geographical Educational Appliances, were enabled, at the close of their work, to report to the Council that in their opinion the object of the Society had been accomplished, and expressed a hope that the impression produced might not be allowed to evaporate, but should rather be ‘fostered to more definite results in this extensive branch of human knowledge.’ From Manchester the London Society’s collection of Geographical Appliances was transferred to Edinburgh, where an address was delivered by Mr. Ravenstein at the opening meeting in the Museum on June 14. It will thus be seen that special efforts have been made and continue to be made to popularise a science which has never, so far as can be ascertained, held its proper place in the educational programme of our schools or universities. We must not, however, lose sight of one important consideration, More remains to be done than to institute a chair, a professorship, a readership. It must be clearly understood on what general lines of study we are about to proceed. Is geography 1 See Preface to Catalogue of Exhibition, 718 REPORT—1 886. to be taught in its full, comprehensive sense as something involving a knowledge, more or less, of mathematics and astronomy, of ancient and modern history, of ethnology, zoology, botany, geology, of men and manners, laws of nations, modes of government, statistics and politics, something requiring in the disciple a quick ear, a searching eye, an appreciation of scenery and outer subjects as well as physical aspects of country, a power of picturesque but an adherence to aecurate description? If so—and I believe I have only stated the qualifications of the travelled and finished geographer—would it not be well to inquire whether the ‘component parts of the science should not be reconsidered, and a subdivision effected which would make it easier to deal with than yeography as now under- ‘stood, under the terms physical, political, and perhaps commercial ? It must be borne in mind that our governments or geographical societies, our boards or our Universities—whicheyer distinguished body takes the matter in hand, separately, it may be, or in concert—will have to cater fora multitude of pupils, and that, whatever change eventitally takes place in programmes of study, the division of school teaching into two great representative branches, classics and mathematics, is a practice which has hitherto, at most public schools, resisted the shock of inno- vation. The maintenance of this time-honoured custom is not so much, to my mind, an illustration of conservative principle—that, we all know, is powerless. against national progress—as the assertion of a profound truth, similar to that which in the region of language separates the Semitic from the Aryan category of tongues. Itis arecognition of the distinction which exists in the human organi- sation between mind and mind—a distinction apparent in the boy as in the man, at school as at college—in the battle of life itself as in the period of preparation for battle. Ido not mean to imply that all school studies fall essentially under one or other of these divisions; but I do believe that the student’s progress will be ‘in accordance with his idiosynerasies; that the student’s taste should be considered in the master’s system; and that, in dealing with geography, we ought not to throw it wholesale into the hands of the professor or reader, but, as a primary measure, separate it to suit the capacity of the classical as of the mathematical intelligence, so that the one. part comes within the province of history and art, the other within the limits of unadulterated science. Attention to both sections should be imperative, so far as attention to classics and mathematics is imperative, but the standard of competence attained in either must depend on the mind and bent of the pupil, who might readily excel in one but fall short in the other, not being even distinguished if the subject of study were undivided. Not six months ago I wrote as follows:—‘ We are authoritatively told that, at one of our greatest public schools, which may be fairly taken as representative of its class, there is no systematic teaching of geography at all, but ‘ that in the history lessons, as well as in the classical lessons, a certain amount of geography is intro- duced incidentally.” Again, if we look at the Universities abroad, it has been found the custom, until quite lately, both in France and Germany, to combine the chairs of geography and history under one professor. Now the “incidental” cha- racter of geographical instruction is a tacit declaration of its unimportance, which every day’s experience shows to be without warrant; and its combination with history may be an expedient to render it less distasteful than it appears as a sepa- rate study. Buta useful hint may be taken from the Continental practice, and a partial fusion of two departments effected, which would commend itself to common sense, and, to judge from the recorded opinions of certain of our educational experts, might not be objected to by head-masters in England collectively. Jet us, then, endeavour to extract from the lessons of conventional geography that part which is inseparable from the study of nations and people, and place it under a new and more appropriate head. In this view, so-called “ political geography,” stripped of its purely scientific belongings, would be taught in connection with history, and made an essential ingredient in the early training of British statesmen, whose after- reputation should be more or less the outcome of a University career, the grounding -of a public or grammar school, or private tuition. It is difficult to reconcile the amalgamation of what may he considered “scientific” geography with history. ‘One is as thoroughly apart from the other as geology is from astronomy.’ TRANSACTIONS OF SECTION E. 719 The meaning of the verbal combination ‘ political geography ’ requires some kind of analysis. Conventionally, and in an educational sense, itis the description of the political or arbitrary divisions and limits of empires, kingdoms, and states ; their inhabitants, towns, natural productions, agriculture, manufactures, and commerce, as well as laws, modes of government and social organisation—eyerything being viewed with reference to the artificial divisions and works made by man. Accept- ing this interpretation of its objects, who can hesitate to admit its palpable and immediate relation to history? ‘The mathematical science which investigates the physical character of territory and territorial boundaries is in this case but a secon- ‘dary requirement and can be always fairly disposed of in the recognition of results. Otherwise, we have simply commercial geography with ethnography, and considera- tions which we may call political in the present but which are undoubtedly historical in the past. Surely, then, it would be wise and reasonable to combine the studies of history and political geography—putting a wider interpretation than ‘the conventional one upon the latter designation in such a manner that the two together should be just the sort of yabulwm dispensed to the rising generation of statesmen, diplomatists, and all who aspire to the name of politician, in its higher sense of capability to promote as well as to discuss the national welfare. An admirable lecture on ‘ Geography in its Relation to History’ was delivered by Mr. James Bryce—the late Under Secretary for Foreign A ffairs—in connection ‘with the recent London Exhibition of Geographical Appliances. Those who are ac- -quainted with it will readily understand why I pause to remark on its enlightened teaching ; to those who have not that advantage I would explain that it seems to embody the arguments of Modern Thought on the important question we are now considering, and that a brief allusion to it is therefore no irrelevant introduction here. The lecturer, seeking to demonstrate that history and geography touch one another in certain relations and interests, laid down the proposition that man is, in history, more or less ‘the creature of his environment ;’ that ‘on one side, at all events, he is largely determined and influenced by the environment of nature;’ and that ‘it is in discovering the different effects produced on the growth of man as a political and State-forming creature by the geographical surroundings in which he is placed’ that one point of contact is found. He, moreover, maintuined ‘that man, ‘although he may lift himself above his environment, cannot altogether escape from its power.’ Dividing the influences thus exercised into three classes, he showed that those arising from the configuration of the earth’s surface affected ‘movements of races, intercommunications, and barriers of separation; that those belonging to climate affected the occupation or abandonment of particular localities on the score of health, fertility, or non-fertility of soil, and consequently commerce -and cultivation ; and that those which owed their existence to natural products unmistakably directed the energies of peasantry and people into certain fixed channels of enterprise—a result which applies to the zoology as well as to the mineral and agricultural resources of a country. He made the very true observa- ‘tion that the ‘animals affect man in his early state in respect to the enemies he has to face, in respect to his power of living by the chase, in respect to the clothing which their furs and skins offer to him, and in respect to the use he is enabled to make of them as beasts of burden or of food’; and he, therefore, concluded that ‘zoology comes to form a very important part of the environment out of which ‘historical man springs.’ A volume might well be written on this suggestive theme ‘alone; and if, as I believe, the proposition of a human being’s dependence on environment be admissible in its entirety, what a field of speculation is open to ‘the inquirer! A condition held applicable to the unreckoned millions of to-day must have had a marvellous effect in giving character to original Man! This conception of man’s environment supposed heads or branches of geography, call bearing upon history, which might be distinguished by names such as ethno- logical, sanitary, commercial, linguistic, political and military, lezal—the last lead- ‘ing to the consideration of the Suez Canal and sea-channels in which several States have interests. As time, however, will not allow me to quote the lecturer's apt ‘and well-put illustrations which followed, I may mention that the express object with which they were introduced was to show how ‘the possession of geographical 7920 REPORT—1886. knowledge, and a full grasp of the geographical conditions’ with regard to some of the leading countries of the world, ‘ will enable a person studying their history to make the history more intelligible and real.’ In strict conformity with this opinion, and in the conviction that the want of geographical knowledge and ‘ full grasp’ of geographical conditions will betray men in power to commit dangerous mistakes, calculated to injure the national prestige and credit, and men out of power to become their upholders in error, I would express the hope that, in any future arrangements which may be perfected for the better education of our country- men, while physical and scientitic geography are invested with a degree of prominence and honour to which they have hitherto never attained, that branch of study which we have been accustomed to call political will be reconsidered and, if necessary, newly defined by competent men. The conclusion at which I have myself arrived -—one which I am quite ready to abandon before the arguments of sounder reason— is that we have here something which belongs mainly to history, and, in such light, its scientific should be separated from its non-scientific elements. A partition should be made which would equally suit the mind of the student whose tendencies are rather towards metaphysics than mathematics, as of him who is a votary of practical science only. Ido not presume to touch upon the action of Universities, except to say that I can conceive no better example could be afforded that the in- tellect of England had due regard for the material interests of England than by the creation of a chair for scientific geography and the relegation of that which is non-scientific to the chair of history. I now turn to the third, or illustrative portion of the subject under discussion. To illustrate, by instances of modern travel and research, the urgency of geo- graphical study to young Englishmen, especially those who from adventitious position, ambition, or ability are likely to hold the helm in any department of State, I see no fitter way than, by a retrospect of the work done, to come to the conclusion whether we, as a nation, would have participated more directly in that. work, or derived more legitimate benefit from it, had we been better instructed. Now this is a delicate question to put, if applied to particular cases, because it involves matters of policy, and belongs to the domain of pure politics rather than to any form of political geography ; but I shall not presume to ask whether we could, or could not, have acted more wisely in this or that diplomatic difficulty, only whether the solution of such a difficulty does not, in point of fact, depend upon a geogra- ’ phical experience which we do not always possess, and cannot always command from others. Having explained upon what particular instances of progress in the field of exploration or discovery I should dwell, at this stage of my address, I will now speak more definitely. Though my own personal experience of travel has been obtained, more or less, in the four quarters of the globe, I cannot but feel that Europe is more familiar to me in its chief cities and highways, and more popular social haunts, for the geography of which there is no demand—notwith- standing abundant and choice material—than as a subject for scientific description. So also with the United States. New York and Philadelphia, and the Hudson River, with all their recommendations, have certainly no gloss of novelty, and my personal knowledge is unfortunately restricted to these points. In Asia, 1 have a. wider field—from the Canton River to the Bosphorus—but for obvious reasons a corner of this will suffice for present purposes. In Africa I have made quite recent acquaintance with the Congo—that great river whose introduction into our maps in its entirety is one of the most notable of geographical feats of modern times. My ex- perience of it was brief and confined to its lower section, but the two months passed at Vivi and between Banana and Isanghila were not without instructive use. Plainly, then, after a retrospect of work lately achieved by travellers and ex- plorers, I will limit such comments as I may have to offer to the Congo for Africa,. and Eastern Persia for Asia. Of the out-door operations of the past year those specially mentioned by the: President of the Royal Geographical Society in London, in his address of May 24, are :—Prejevalsky’s journey from Lob Nor to the populated districts of Eastern Turkistan, and from Khotan back to Russian territory vid Aksu and the Tian-shan ; Mr. Needham’s expedition to the Za ul-chu; Colonel Woodthorpe’s examination of TRANSACTIONS OF SECTION E. 721 the country between Assam and the Upper Irrawadi; the Anglo-Russian survey of the northern frontier of Afghanistan and Indian topographical survey in Burmah, the Kangra Hills and Panjab Native Hill States, the Andaman Islands and Baluchistan ; and Colonel Tanner’s exploration of the Tibetan frontierregion. Al these are in Asia. In Africa the Portuguese and German expeditions—the latter proving the Lualaba to be the true head-stream of the Congo; the travels of the Baptist missionaries; and Lieutenant Weissman’s exploration of the Kasai were honourably referred to; and I may here mention that a highly interesting paper by Sir Francis De Winton has been since added to the reports of the officers of the Belgian International Association. The President further referred to work done in the east of Africa by Mr. Last, and Bishop Smythies of the Universities’ Mission, as also by Major Serpa Pinto and his representative Lieutenant Cordozo in carry- ing out the Portuguese expedition organised from the Mozambique ; to the pro- ceedings of agents of German commercial societies; to the sad fate which befell Bishop Harrington at the hands of the King of Uganda; and to Dr. Fischer's adventurous but unsuccessful journey, with intent to reach the Russian traveller, Dr. Junker, by moving along the eastern shores of Victoria Nyanza—an attempt supported by Dr. Lenz (then at Stanley Falls) from the south-west. He also touched on Mr. Thomson’s negotiations in the Central Sudan; Mr. Montagu Kerr's hazardous journey from the south across the Zambesi; Mr. Farini’s passage through the Kalahari desert, and Sir Charles Warren's surveys in Bechuanaland. Besides Asia and Africa, public attention was drawn to Mr. Forbes’ and other expeditions for the exploration of New Guinea ; to the report of Mr. Simons on the Goajira Peninsula, and that of Mr. Wyse on the Columbian Isthmus and Panama Canal. South America, moreover, came in for a share of honour with respect to the ascent of Mount Roraima. Among less known expeditions—of which something, however, has been heard in this country through the scientific periodicals—may be mentioned one undertaken by Dr. Bunge and Baron Toll for the Russian Imperial Geographical Society. These explorers have been oceupied during the past year in examining the northern shores of the frozen sea and islands of New Siberia. The Upper Yana and its sea- mouth were the points to which the chief attention of one or other of the travellers was mainly directed, and the Baron explored three other rivers in the same locality. A highly favourable report of the results obtained has been received, and this last spring has probably witnessed a renewal of work. From the ‘ Proceedings of the French Geographical Society ’ we learn that in Eastern Siberia also the explorations of M. Martin last autumn between the Lena and Amoor were so carefully conducted that his itinerary has been accepted for adoption and publication by the Russian staff. Much might be said, too, about a recent scientific mission of M. Aubry to Shoa and the country of the Gallas; a journey by one of the missionary fathers to the plateau of Amboella east of the Portuguese territory of Mossamedes,. and the active movement of the Government of the Argentine Republic and individual explorers on the Bolivian frontier and the Vennejo and Pilumayo Rivers: but time would fail me to repeat the nominal record only, With one exception I omit all reference to ‘ projected’ expeditions, of which the number is unusually great. The exception will be disposed of in very few words. It relates, perhaps, rather to a mooted subject than to a new project, the research of the Antarctic Polar Seas, on which a paper was read last year at the Aberdeen Meeting by Admiral Sir Erasmus Ommanuey. Men’s minds are so fully occupied at the present hour with the thousand and one practical interests which arise like sparks out of the fast- rolling wheel of Progress, that the theory of an unknown polar region may not _ possess the fascination which it exercised in days when steam power had been less developed, and electricity had not exhibited a tenth part of its now familiar uses and effects. Nevertheless, there is something to stir the imagination, even of this unimaginative age, in the theory of a South Polar Sea; and there is something practical in the proposition besides, for it tends to give substance and meaning to the unknown. If the object of exploring that comparatively neglected corner of the globe commend itself, as I know it does, to many; assuredly the project opens 3A 1886. 722 REPORT—1886. a worthy field of enterprise for this nation above all others. The perils may be, as stated on good authority, far greater than those of the Arctic Seas, but the conditions of the two poles greatly differ, and it is most desirable to find such a winter quarter within the Antarctic Circle as has never yet come within the experience of any human being. Those interested in this important question may remember that a Committee was appointed to report upon the advantages to be derived from further exploration of the immense region referred to—near which, some fifty years ago, James Ross made his famous discoveries. Hitherto, for reasons which might readily be explained, no report has been issued; and perhaps the wiser and the better preliminary step towards bringing matters to a successful issue would be to expand and’ strengthen the Committee by the accession of influential members. I now leave the subject in the hands of experts, who alone are qualified to deal with it in detail. To return from this brief digression. There are two regions in which geo- graphical activity has been evinced in a remarkable degree: both are in that large continent which one who knows it as well as any living man has qualified as ‘dark ’"—the east and west coasts of Africa. It is really astonishing to trace the changes in a map of Africa during the last quarter of a century. Large spaces that were quite blank have been filled up with conspicuous delineations of moun- tains—fine lines representing rivers, crossed by or connected with finer lines of affluents or feeders—with names, circles, and dots for towns or villages. Yet as I now contemplate that map in its latest form, it seems to me that hundreds of spots visited have yet to be indicated, and that the coast lines of the Indian Ocean on the one side and the Atlantic on the other, are teeming with life imported, as it were, from Europe. Singly or collectively, emissaries and missionaries—would-be settlers or mere explorers—the number of these now in movement foretells in the course of time a change in the political divisions of the country, whatever the re- sult for good or evil. For the sake of argument let us take the whole extent from 20° N. to 30° S., leaving out Morocco, Algeria, Tunis, Tripoli, and Egypt, as poli- tical considerations more or less understood in England. On the west, Germany has stepped in to hoist the flag of colonial power, and is to be recognised at the Cameroons. France has possessions and protectorates between Senegal and the mouths of the Niger, which promise development and consolidations such as it is now impossible to estimate. Below the Gold Coast she has just added to the Gaboon, by agreement with the Belgian-African International Association, an amount of territory which gives her, in place of a comparatively small settlement, a continuous coast line of more than 350 miles, touching inland a great portion of the right bank of the Congo. Those who would know how her agents work for her have only to read the narrative in the publications of her Government, her geographical society, or the records of her missionary fathers. They will there learn that if her soldiers find active service in Senegal, the Péres du Saint Esprit are not slack in peaceful attempts to educate and civilise the natives of the Gaboon. Spain and Portugal have also possessions which have been lately extended on the seaboard of West Africa; and the international partition effected at Berlin has confirmed to the latter her right to lands which had been denied on more than one distinct occasion during the last half-century. As to individual explorers of the west coast within the last year or two, I need only refer to the names mentioned in the address of the President of the Royal Geographical Society, and which I have just repeated. Others might be added were it necessary; but they would scarcely strengthen the case. For the east coast, again, Germany has annexed territory in the neighbourhood of the Sultan of Zanzibar; while the names of in- dividual explorers and settlers are legion. Of these I will simply recapitulate some, without further comment. These are Major Serpa Pinto and Lieutenant Cardozo ; Herr Colin and Captain Chaders; Messrs. Arnot and Giraud ; Mr, Last, Mr. H. H. Johnston, Consul O’Neill, and Mr. Richards (of the American East Central African Mission) ; Bishop Harrington and Bishop Smythies; Governor Vieira Braza of Tété and Padré Courtois; also Herr Reichard, who, by the death of his last remaining colleague, Dr. Bohm, has become the sole survivor of the German East African Expedition, The names are taken almest at random and TRANSACTIONS OF SECTION E. 723 include, besides our own countrymen, those of one or more representatives from France, Belgium, Germany, Portugal, and America, This drawing within the pale of civilisation of semi-barbarous States, this in- clusion among common things of the uncommon and strange by the independent or joint action of individual agents, is 2 matter which cannot fail to arouse a deep interest in those European Powers whose position is secured or prestige enhanced by the maintenance of empires, kingdoms, or colonies beyond the seas, over and above their home possessions. It has been seen that France and Germany have marked their sense of the situation by fresh annexations. The first, it is true, has made her West African gains a mere supplement to the more palpable advantages obtained under treaty with Madagascar and Annam; but M. de Brazza’s exertions on her behalf have won the important line of the Ogowi river—the additional terri- tory on the seaboard, to which we have referred, being a bargain of comparatively trivial cost. England, in the meanwhile, has refrained from active interference, fur- ther than reserving for herself certain rights connected with the Niger and Gold Coast, and entering into treaty with Portugal in respect to the LowerCongo. The reservation was a political fact to which we need not do more than allude; but the treaty calls for a word of remark. It was never ratified, and fell through in embryo. I do not say that a knowledge of Africa better and more comprehensive than that usually taught in English schools would have averted this result; but I do say that to treat so important a question a knowledge of geography, such as that which I would combine with history, would have been the best protective weapon. That low and uninyiting mouth of the Congo—that unhappy birthplace of man- groves and of malaria—that much desired and yet most undesirable site of a few European factories, with enterprising but fever-stricken tenants—has a story of its own; and only those who know that story, in its geographical, ethnological, commercial, and political bearings, can understand why it is coveted by this or that European Power, and consequently what view England, when appealed to, should have taken regarding its disposal. All is now over; the Congo has been divided out under the Congress of Berlin. From West Africa we turn to the East—to countries west of the northern frontier of India. Three of these merit our serious attention, 7.e., Afehanistan, Baluchistan, and Persia, more particularly their history and geography, and full information on them is available in books. Nowhere is this to be found in the comprehensive form that would necessarily be adopted were geography honoured with professional chairs ; but, in the absence of the appropriate manual, search must be made in encyclopedias, gazetteers, and volumes of history and travel. Afghanistan has been of late years so much the subject of official correspondence that the blue book is perhaps as useful a record as any other from which to draw the more im- portant details on the character of the country and people. Baluchistan has a divided history. Her eastern half, contiguous to, and immediately connected with British India, is to all intents and purposes under the protection of that em- pire; her western half, till within the last fifteen years, encroached upon by Persia, is equally amenable to our influence, and should profit from English advice and help. Persia is never in lack of European travellers who delight to place on record their experiences of a country which with all its drawbacks has the immense advantages of grand associations and a charming climate. Nor are its people the effete race that some would suppose. Many of them, whether in the higher, middle, or peasant class, are endowed with energy and activity which need but occasion to draw out; and if cruelty on the part of governors and extortion and peculation on the part of high officials are painfully recognised native qualities, there is great kindliness and hospitality shown to strangers by the same classes, and, let me add, the love of poetry is universal. The servant who corrects his master’s faulty poetical quotation from his humble post behind his master’s chair can hardly be lost in Vandalism. I regret there is no paper to be read in our Section on Persian geography, but may incidentally mention that one of our latest travellers in that country, Mr. Rees, who will favour us with his impressions of Northern China, has published a graphic account of his recent journey, by a direct and little known route, from Kazyin to Hamadan. « 3A 724 REPORT-—1886. It is a subject of much congratulation that Boundary Commissioners are now made the means of advancing the cause of Science as well as of political security. Their proceedings are no longer confined to the little-attractive blue book, nor doomed to the disguise and dilution essential to adapt them to the shelves of a cir- culating library. The progress of a mission may now be reported stage by stage for the public information, and fresh descriptions of fresh countries may be read in the daily prints, recorded with the minute accuracy of a photograph. Nor are the acts and words of the chief or members to be done and spoken in the interests of Government alone, registered in official foolscap, and marked confidential. Out- door diplomacy, especially in Eastern countries, may have its occasional solemn aspect, but it is,in the main plain-spoken and Bohemian, ‘The appearance of a Commissioner may be described, his official or general conduct discussed, his opi- nions and habits criticised, and his remarks, whether sober or facetious, given to the world—I might almost add the conferences in which he takes part, revealed — without let or hindrance of any kind. All this is a distinct gain to the public, and can be no cause of distress to the Commissioner, working in an honest and loyal spirit—though it may not always be politically expedient. In any case the in- formation so imparted may be rendered invaluable, both in a patriotic and educa- tional sense; for it is eminently calculated to elicit the’ views of competent men who have no other opportunity of acquiring the data on which to form them than that afforded by the Press. Whether these views would always be held acceptable is a separate question which need not here be considered. And now let me ask you to accompany me for a few moments to the camp of the Russo-Afghan Boun- dary Commission, of which we have telegraphic intelligence up to August 26, or only a week ago, and from which a letter in the ‘Indian Pioneer’ of July 18 brings full particulars under date Kham-i-Ab, June 15. For obvious reasons it would be out of place here to refer to the political knot which the Commissioners are seeking to untie. Had it been otherwise, I should have endeavoured to find a qualified exponent to admit us into the diplomatic secret, one which is so closely allied to geographical investigation. But the objection does not apply to the geography of the country traversed by the mission. ‘ Kham-i-Ab’—I have written it as printed in the ‘ Pioneer ’—is a point near the Oxus, north of Andkii. I shall not myself attempt to travel so far; but it affords me much pleasure to state that the actual scene of territorial demarcation and its immediate vicinity will be described by a gentleman who has made a professional study of this as well as of similar questions of political geography. In the meantime let us take a rapid glance at the tract between Quetta and the Helmand, a distance estimated at nearly 320 miles, of which Nushki is not quite third. I take my figures from Major Holdich’s notes, in the ‘Proceedings of the Geographical Society, which include the stages and distances to Galicha; and from a letter in the ‘ Pioneer’ of November 19, 1884, civing the distance from Galicha to Khwajah Ali on the Helmand at 53 miles— checked, moreover, by the above-named officer’s statement that a place called Shah Ismail is halfway between Nushki and Khwajah Ali. . The country traversed was for the most part dreary and waste. Within 40 miles from Quetta the soil seemed ‘ poor,’ and ‘ the cultivation scanty,’ while it was not easy to obtain ‘such necessary supplies as wood and chopped straw.’ In 40 miles further it was ‘difficult to describe the general appearance of poverty and desolation’; while for the next 31 miles water was only procurable at one place— “a narrow little oasis.’ Then came a trying night march ‘ of 25 miles over ground always rough and stony, and occasionally steep for laden camels.’ As for the climate, the sun was intensely hot in the daytime, the cold bitter at night, and a ‘fine white dry dust’ was blown about in constant clouds. The last 10 or 12 miles into Nushki was mainly along the bed of a stream. From Nushki to the Helmand there were three routes available, of which the Mission chose the most northerly, on account of its greater facilities for securing a suflicient supply of water. For nearly 80 miles of this distance—or to Gazchah—the characteristic of the ground was a flat, hard surface, commonly known in India and neighbouring countries as put, easy to cross, but monotonous to contemplate, and the writer’s description of ‘the same wide expanse of limitless plain, the same stunted undergrowth, and occa- TRANSACTIONS OF SECTION E. 725 sional sun-ridges (or drifts) of a few yards only in width, but deep and shifting, with an occasional hut or ziydrat (the dwelling of a desert fahzr), like an inverted bird’s nest of sticks adorned with quaint devices, leaves little wanting to complete an intel- ligible picture. From Gazchah onwards we are told that ‘a marked geographical change occurs,’ and that the line of march for about 90 miles further is ‘a mere track, winding and twisting over the successive waves of rolling stone-covered plateau hills, with the line of distant rugged peaks to the south; a few scattered isolated hills on the northern horizon, and one or two remarkable conical peaks rising straight up from the plain, forming a peculiarly definite line of landmarks for the marching force. The direction at night was indicated by fires kept up at intervals of a few miles.’ The last 50 miles or so to the river is ‘a troublesome strip of waterless desert.’ It should be noted that, with one exception, where it was reached at 25 or 30 feet below surface level, Major Holdich states that five to six feet is about the average depth at which water is found between Nushki and the Helmand. Few can deny that all this is very useful and interesting information. So far back as the spring of 1808, Capt. Christie had made an adventurous journey to the left bank of the Great Afghan River, also from Nushki, whither he had pro- ceeded from Kelat in company with Lieutenant Pottinger. He reckoned the dis- tance at 191 miles, or somewhat Jess than the Mission’s estimate. When Sir Charles MacGregor and Captain Lockwood passed through Western Baluchistan in 1877, they separated at a place called Lal Khan Chah, about 60 miles below the Helmand, to return, by different routes, to the Sind frontier post of Jacobabad, Captain Lockwood taking the upper route by Nushki and the Bolan, and Colonel MacGregor the lower by the Baila country; but they did not penetrate so far north as the Helmand itself. Nushki has, however, been more than once visited of late years by British officers from Kelat. ‘Khwajah Ali,” writes Major Holdich, ‘ where the Boundary Commission first struck the Helmand, exists only in name.’ Neither he nor the correspondents of the ‘ Pioneer’ mention its distance from Rudbar, but it may fairly be concluded that it is not many miles to the eastward of that place. The river appears to have been forded at Chahar Burjak, whence the party moved up the right bank to Kala‘i-Fath and Kohuk, passing on through Northern Sistan and its reed-beds to the Afghan territory of Lash Juwain. Having myself visited the locality at which we have here arrived, it might naturally be inferred that I should pause to say something regarding it, but I will not weary you by recurring to narratives and descriptions published many years ago, reserving all personal experiences to guide me in the general conclusion to be submitted. How the British Commissioners for delimitation of the Russo-Afghan frontier proceeded from Lash Juwain to the immediate vicinity of Herat, and on to the quasi-Mesopotamia of Badkhiz, I leave to be dealt with by the authority to whom I have already referred. Time, too, warns me that I have detained you long enough, and that if my illustrations apply to the argument entrusted to your consideration, the application should at once be made evident. To my own mind the bearing is clear. A Boundary Commission represents the three branches of Science, Research, and Diplomacy—in other words, all that comes under scientific geography and political geography. The first, you will understand, comprises the survey of country, map- ping, and determination of localities. The second has to do with the definition of territorial limits, and, in such sense, with history, ethnology, and laws of nations. That all this has been done, and well done, on the present occasion is not disputed, any more than that enlightened attention will be given to the due disposal of results. But are not these matters of sufficient importance to be taught as daily lessons in our schools, and presided over in university chairs? Even those barren and desolate lands of which we have now spoken—and I have myself traversed many miles of such, some, indeed, in the near vicinity of the Perso-Afghan frontier, between Herat and Farah—they may have a meaning which can only be understood by the ini- tiated, by those wlio have made them a long and seriously-undertaken study. To the many they are but miserable deserts displayed in incomplete maps; to the few they may have a value far beyond their outer show. Were I asked to sketch out the 726 REPORT—1886. kind of manual which might be useful in preparing officers for dealing with ques- tions such as these, I would solicit reference to a late paper which I contributed to a quarterly journal, and which I have once before quoted. In it, I stated :— ‘ Asia itself is a stupendous study, but the difficulties may be smoothed to the learner by the judicious employment of method, which, after disposing of essential generalities, would naturally tend to division and subdivision. The first would imply a region such as Turkestan; the second, a group of States or single States only, such as Bukhara and Khiva. Given, then, a particular area, the next con- sideration should be to explain its physical geography. ‘This should comprise the scientitic description of its mountains, rivers, and valleys. Its orography should be comprehensive in respect of direction, elevation, watersheds, and connection with plains and plateaux; its hydrography should treat of sources and mouths, basins, drainage, and connection with lake and swamp. Climate and the more im- portant forms of animal and vegetable life should succeed in due course; indeed, something of geology, zoology, and botany, and it may be more besides, might reasonably be added to satisfy the requirements of purely scientific teaching. After science, history would follow, and, joined to history, an account of the re- ligion, manners, and customs of the people, as affected by the historical narrative ; a statement of the artificial lines of separation which have replaced natural boun- daries in consequence of the wars, revolutions, or arbitrary changes which have characterised certain reigns or epochs; an exposition of the form or forms of government in vogue at different periods; and, finally, a chapter on trade and commerce, including a notice of indigenous products and manufactures. Maps, applicable to relations of territorial changes, would be of immense value ; and an historian’s criticism on these relations, if offered in that fair spirit which alone is justified in composing history, would be an indispensable complement.’ But it is not the preparation of a manual which I have come before you to advocate, This would be one of the many fruits of a system now sorely needed for establishing at home the true position of geography as apprehended to a great extent abroad. Iam one of those old-fashioned and perhaps obsolete persons who believe, not in the infallibility but in the ability of this country as a governing Power. If that ability is proved in the creation and growth of its colonies, it is no less distinguished by an unselfish tendency to lead those colonies to govern themselves. But the unselfishness would be selfish if confined to the action of Great Britain alone. It should be an example to other States and Powers to ‘go and do likewise.’ That example, rendered available in International arrangements by fitting action at fitting opportunities, can only be carried out by a knowledge of geography in its widest sense. As to questions of territorial boundary, in Asia or elsewhere, we may be fortunate in having able officers to decide, and wise Govern- ments to scrutinise decisions: but one generation may not keep pace with another generation in the character of its Governments or agents, and the doctrine of chances is not a safe one in a matter of State urgency. Plainly, let us not lose the immense advantage given to us by Providence owing to the want of systematic knowledge in a branch of science in which we are shown to have been outstripped by Continental nations, but which all historical precedent warns us that it is our duty to foster to the uttermost. The following Papers were read :— 1. Notes on the Extent, Topography, Climatic Peculiarities, Flora, and Agricultural Capabilities of the Canadian North-west. By Professor Joun Macoun, M.A. The author describes the geographical and topographical features of the North- west, and shows that its leading feature is that of a plane sloping to the north. From this results a nearly uniform climate. A uniform climate gives unity of natural productions, and cereals or other crops, if successful on one part, will therefore be equally so under the same conditions in another. TRANSACTIONS OF SECTION E. 727 2. The Canadian Pacific Railway. By ALBxANDER Brac. The author explains the circumstances under which the federation of the British North American provinces was brought about, and gives some account of the acquisition by Canada of the north-west territories and the admission of British Columbia into the Dominion. He points out that the Transcontinental Railway through British territory was the very essence of the agreement between the different parts of Canada to unite under one system of government, and shows as a result of this the building of the Intercolonial and Canadian Pacific Railways, connecting the Atlantic and Pacific Cceans. He then proceeds to recount how the construction of the Canadian Pacific Railway, as a Government work, proved a failure, and that therefore the contract was entered into with the present Canadian Pacific Railway Company for the construction of the road. He next gives an out- line of the progress of construction from the beginning of the work to its comple- tion, and following this a description of the country traversed by the railway, at the same time showing the various sources of traffic upon which the line depends, and is likely to depend in the future, for its revenue. The condition of the north- west territories of Canada before and since the year 1881 is then described, showing that to the railway is due the rapid development which has taken place in so short a time. The author then goes on to say that a large traffic in cattle and grain from the Western States of America is certain to flow through the channel of the Canadian Pacific Railway to the seaboard, and that it will thus be an outlet for the produce, not only of North-western Canada and British Columbia, but also for a large portion of the United States. Mr. Begg also demonstrates that the trade which has already commenced between Canada and Australia, China and Japan, vid British Columbia, is likely to assume considerable dimensions, and to prove a very important source of revenue to the railway, and that the commerce also between Canada and the Australian Colonies is certain to be largely augmented by the Canadian Pacific connection with the British Columbia coast. In this respect the author points out that Canada is likely to prove a powerful rival to the United States. The imperial aspect of the enterprise is then dealt with, and shows how great an advantage it is to Great Britain to have an independent route through British territory for the protection of her possessions in the Kast. From a commercial standpoint the author maintains that the mother country cannot but derive very material benefit from this route in her trade relations with the Australian Colonies, China, and Japan. The paper concludes with a number of tables showing the mileage of the Canadian Pacific Railway lines operated by the company, the equipment of the road on December 31, 1885, comparative statements of the earnings, and a com- parison of times and distances by the West to the East. 3. A new Trade Route between America and Europe. By Hucu SurHERLAND. The settlement and cultivation of the Canadian north-west have directed public attention in that country to the necessity of a new trade route to Europe. It has been found that a railway carriage of 1,800 miles before reaching a seaport is a serious drawback to the prosperity of that region, and places the settler at a great disadvantage in competing with the other wheat-producing countries of the world. With the object of getting on at least terms of equality with those rival countries an agitation was begun a few years ago to open up an outlet through Hudson Bay, and a railway has been projected from Winnipeg and Regina to Port Nelson, at the mouth of the Nelson River, which, when completed, will bring the north-west upwards of 1,000 miles nearer the seaboard than it is at present. The Canadian Government, anxious to encourage the enterprise, fitted out an expedition to explore the strait and bay, with the view primarily of determining the practicability of the route for commercial purposes, The first expedition was sent out in 1884, and observing stations were established along the strait, These 728 REPORT—1886. were relieved the following year, and the information thus obtained, together with the evidence of experienced navigators which was collected by a special committee of the Canadian Parliament, have satisfied the people of that country that the route is entirely feasible. It is confidently expected that this new trade route, already in process of development, will create a revolution in the commercial traffic of the vast interior of that continent on both sides of the international boundary. Minnesota, Dakota, Montana, and Wyoming, with their immense productions of wheat and cattle, are naturally tributary to that route, as well as the whole of the Canadian possessions west of Ontario. A reference to the map will show how far down into the heart of the continent Hudson Bay extends, and how favourably it is situated for commanding the entire trade of that vast territory. It would seem as if nature intended that it should be the outlet, offering as it does a seaboard within convenient reach of the districts named, and virtually placing them as near to European markets as Ontario, Western New York, and Ohio now are. The attention which has been given to the bay in consequence of this new project has resulted in increased knowledge of the resources of that great inland sea, Salmon, seal, whale, and walrus abound in great numbers, while the coast regions of the bay and strait are rich in minerals, The region of country draining into James’s Bay is covered with valuable timber. Besides offering a new and advantageous trade route between Europe and America, it is not improbable that the utilisation of those waters for such a purpose will soon be followed by the development of fish, timber, and mining industries of great and practicall inexhaustible richness, 4, Proposed new Route to the Great Prairie Lands of North-west Canada, vid Hudson's Strait and Bay. By Joun Ran, M.D., LL.D., F.R.S., F.R.G.S, The project of opening a new route through Hudson’s Strait and Bay by steamer, and from the west shore of the latter by railway to Manitoba, is being undertaken with the most praiseworthy motive of making a shorter and cheaper route for transmission of emigrants to, and for carrying grain and other produce from, the prairie lands of Canada than the present means of transport by lake and railway by the St. Lawrence river and Strait of Belle Isle to England. Earnestly desiring that, if practicable, this great work should be carried out successfully, I fear, however, that failure is more probable than success, and a failure would be an immense misfortune. There are a number of adverse circum- stances that have either been entirely overlooked or not taken sufficiently into consideration. These difficulties are wholly connected with the navigation of the Hudson’s Strait, and have nothing whatever to do with the navigation of the Bay nor with the construction of the railway from thence to Manitoba, both of which are easy enough. This route, if established, would shorten the distance by 400 or 500 miles—more or less, according to the position on the prairies from which the measurements began—and would give about two days quicker time to a loaded steamer of ordinary speed; an advantage more than counterbalanced by a probable average detention by ice of three or four days on each voyage through the strait. The disadvantages are— 1. The short time—three or three and a half months (?)—during which the strait is sufficiently open each season to allow a steamer to get through without much hindrance by ice, whilst on the other hand the great Canadian lakes are perfectly open for fully six months, and the Strait of Belle Isle navigated for at least five months by the Allan steamers. 2. The danger to a large heavily laden steamer, whether of wood or iron, if caught in an ice-nip; also the higher rate of insurance consequent on such danger. 3. The uncertainty and rapidity of ice movements, which bafile the skill and experience of the oldest whaling captains, and are so well described by Lieutenant Gordon, who commanded the Neptune in 1884 and the Alert in 1885, on TRANSACTIONS OF SECTION E. 729 voyages of inspection of the intended new route, whose opinion agrees closely with the far longer experience of the Hudson’s Bay Company’s captains in sailing ships, and of my own (much more limited) in the years 1833,! 1847, and 1854. Lieutenant Gordon says that in the first half of July a steamer would take ten days to pass through the strait—a distance of 500 miles—or fifty miles a day ! If this is correct the new route will occupy longer time, be more dangerous, and less favourable in every way than that by the St. Lawrence. Up to the middle of July the ice-pack driving down Davis Strait fills up more or less closely the eastern entrance of the strait, whilst at its western end the same thing happens during a part of August or of September by the driving to the south of the 40,000 square miles of ice-floe from Fox’s Channel. At one part of Hudson’s Strait the compasses used to be, and probably still are, useless, owing to some local attraction. FRIDAY, SEPTEMBER 3. The following Papers were read :— 1. On the Place of Geography in National Education. By Dovctas W. Fresuriztp, M.A., F.R.G.S. 2. Can Europeans become acclimatised in Tropical Africa ?? By Rozert W. Ferny, M.D., F.R.S.E. With the exception of Cape Colony and a small portion of the north-west, the whole of Africa is in the tropical and sub-tropical zones. This immense region is of great importance, and could it be colonised by Europeans it would be of great advantage to the civilised world. Acclimatisation is the process, oftentimes slow, by which persons become adapted to, and so retain health in countries having a different climate from those in which they were born. This acclimatisation may be in part effected by changes taking place in the individual or in the race, and in part by hereditary modification of constitution, In some places real acclimatisation is impossible, but in nearly all a person may accommodate himself for a certain time to almost any climate. Great changes have taken place in the location of different races, but these changes have taken place gradually. There is a marked difference in the possibility of withstanding climate in various races, and in each case we must examine the power of resistance possessed by any given national constitution, in order to decide whether it may successfully acclimatise itself in a tropical country when perma- nently colonised there. The difficulties with which Europeans have to contend in tropical Africa are heat, moisture, malaria, special diseases in special districts, &e. It is probable that southern European nations could withstand these obnoxious influences best. In tropical Africa there are great differences of climate. (These differences, especially between the coast line and the interior, were next explained.) The coast line and the banks of rivers for the first 200 miles are most injurious to Europeans, and the difficulty of reaching the interior is the greatest hindrance to acclimatisation. Next followed a description of the various comparatively healthy inland districts. 1 In this year both the ships to Hudson’s Bay were shut in for about three weeks in close-packed ice near the east end of the strait in July. The ships were one and a-half mile apart, yet lady passengers walked easily over the floe from one to the other. On-attempting to get home both ships were stopped by the Fox Channel ice early in October, and had to winter in the bay. Before giving up the attempt to force a passage through the pack two feet depth of ice was formed on the foredeck, and the ship was set down more than two feet by the head by the weight. * Printed in eatenso in the Scottish Geographical Magazine, Nov. 1886. 730 REPORT—1886. I think it is almost impossible for Europeans to do more than accommodate themselves to the coast climate for a short time (two or three years), but given some means of rapid transport, such as a railway, to carry them over the dangerous belt of malaria on the coast, it would be quite possible for them to thrive in the mountainous regions and high plateaux of Central Africa, with proper care and sanitary surroundings. The climate of Central Africa is not necessarily more fatal to life than that of India. We have now the advantage of greatly increased know- ledge of tropical climates, so that precautions can be taken which were not dreamed of when India was added to our empire. “ 3. Further Explorations in the Raian Basin and the Wadi Moileh. By Core WHITEHOUSE. The author exhibited maps, diagrams, and photographs showing the cartography of Middle Egypt and the Fayoum, from the papyrus map of Boulaq, completed by the fragments discovered by him, to the map of his expedition in February (1886), accompanied by a staff of engineers detailed by the Government, and in April with Col. Ardagh, C.B., R.E., and an admirable map of the Charaq basin, prepared expressly for this paper by Monsieur VY. Giardini, of the Egyptian Cadastre. Diagrams of the Nile floods, sections of the Bahr Jousof, and photographs of this canal and the adjacent desert showed that a large volume of water (circa, a milliard of cubic metres) could be annually conducted into the Wadi Raian. The line of levels run with the aid of Mr. Stadler proves that there is a depth of from 100 to 250 feet below high Nile throughout an area of at least 400 square miles. Photographs and ancient maps show that the ruins in Mdileh—neyer visited, with one possible exception, prior to the visits this year of Dr. Schweinforth and the author—are identical with Dionysias. Thus the Wadi Raian has been identified in position, shape, and depth with the Zacus Meridis of the Greeks and Romans. The project of its restoration is now actively occupying the attention of the proper authorities. 4. Recent Exploration in New Guinea. By Captain Henry Cuarites Everitt. The author of this paper commanded an expedition to New Guinea organised by the Geographical Society of Australasia. The expedition left Sydney in the steam launch Bonito in June 1885. The Hon. John Douglas and the Rey. 8. MacFarline accompanied it to the entrance of the Fly River. For a long time nothing was heard of the explorers, but towards the end of October it was rumoured that they had met with a disaster, and the Rey. S. MacFarline was giyen a circumstantial account of their massacres when he visited the Fly River to make inquiries. This alarming news naturally caused much anxiety.