. 4 S' 2 » ye tned i} 1 ak at . ee i les A Re , ree tttat : ; geegeeteees ‘ Wetnistereess of ete! poset trates eg: = ” int of y a gh hh es Ax ye ¢ oat. opis Nerd 4 REPORT FORTY-SIXTH MEETING oa BRITISH ASSOCIATION ADVANCEMENT OF SCIENCE; HELD AT GLASGOW IN SEPTEMBER 1876. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1877. [Office of the Association: 22 AtpemaRtE Srreet, Lonpon, W. | PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STRERFT, CONTENTS. ARRAN Oxssecrs and Rules of the Association «...........csevnceesecs Places of Meeting and Officers from commencement ........... Presidents and Secretaries of the Sections of the Association from SaESERIALAE STEROL HU, Ab. sch nits ig vce ts oo Guat eke Sie) ale auc witli cg aheReehe ede re eraaN EMR CLIT ON ress fakale 2 feb eh teensy keine" oie. Cageags eco ste. ce + sie « Memmres to the Operative’Classes 26 )..8 2.22 ee ede ees Table showing the Attendance and Receipts at Annual Meetings .. BRITA RA GOO LLU ailz oS) sancseialerss Sasgels aiaaty eis, ve epee s sue vis ss Eeacersot Sectional Committees: / siete eee eee ues enema MTC, 137 Oi fever ls 3 a bc ain ots) 5.6 in! vin vd de a nee _ Report of the Council to the General Committee ................ Recommendations of the General Committee for Additional Reports BMImepEALCNeS 1 BUICNCO se Sele W fs sod et ale we dee vide 6 EG BUGTISY, EXT EIU, . wutwisi isl: Bieket msi Aapord ee (5 Wine Bleep «ens rote in TS78 1. Paes, Tadeo a). tye Lehi oo ees General Statement of Sums paid on account of Grants for Scientific RMD clei ee av cis. fae we ee eben ae thm aan oth Arrangement of the General Meetings ................ ce eeeeee Address by the President, Professor Thomas Andrews, M.D., LL.D., PrP OE risks OUGe o's Se laic'e » 0 ow SS knee Kass REPORTS OF RESEARCHES IN SCIENCE. Twelfth Report of the Committee for Exploring Kent’s Cavern, Devon- shire, the Committee consisting of Joun Evans, F.R.S., Sir Jonn Lussocx, Bart., F.R.S., Epwarp Vivian, M.A., Gzorce Busk, F.R.S., Witti1am Boyp Dawxrns, F.R.S., Wint1am Aysurorp Sanrorp, F.G..5, Joun Epwarp Lez, F.G.8.,and Witu1am Peneetty, F.R.S. (Reporter) 1 a2 iv CONTENTS. Report of the Committee, consisting of Prof. Syrvester, Prof. Caytry, Prof. Hirst, Rev. Prof. Barrnotomew Price, Prof. H. J. 8. Suiza, Dr. Srorriswoopr, Mr. R. B. Haywarv, Dr. Sarmon, Rev. Prof. R. Townsrnp, Prof. Fuiter, Prof. Krnzanp, Mr. J. M. Writson, Prof. Heyricr, Mr. J. W. L. Guarsuer, and Prof. Crrrrorp, appointed for the purpose of considering the possibility of Improving the Methods of Instruction in Elementary Geometry, and reappointed to consider the Syllabus drawn up by the Association for the Improvement of Geometrical Teaching, and to report thereon. Drawn up by Mr. DEVAS oc ore cee, dia cveys «eh he EE, SE CED, Code ne ss ooo Results of a Comparison of the British-Association Units. of Electrical Resistance. By G. Curystan and 8. A. SAUNDER..............-- Third Report of a Committee, consisting of Prof. A. 8. Herscuen, B.A., F.R.A.S., and G. A. Lezour, F.G.S8., on Experiments to determine the Thermal Conductivities of certain Rocks, showing especially the Geo- logical Aspects. of the Investigation... . 2.24)... spies f+ Small ale Report of a Committee, consisting of the Right Hon. J. G. Hunparp, M.P., Mr. Coapwick, M.P., Mr. Morrzy, M.P., Dr. Farr, Mr. Hat- tert, Professor Jnvons, Mr. Newmarcu, Professor Leone Luyi1, Mr. Herywoop, and Mr. Suann (with power to add to their number), appointed for the purpose of considering and reporting on the practi- cability of adopting a Common Measure of Value in the Assessment of Direct Taxation, local and imperial. By Mr. Hatrerz, Secretary Report of the Committee, consisting of Professor Crrrx Maxwett, Pro- fessor J, D. Eynrerr, and Dr. A. ScuusrEr, for testing experimentally Occ bl Ee) ae rs ss ean At eee Ey cater, oe Report of the Committee, consisting of the Rev. H. F. Barnes, H. E. Drzussrr (Secretary), T. Hartanp, J. E. Harrie, T. J. Monx, Pro- fessor Nnwron, and the Rey. Canon Trisrram, appointed for the pur- pose of inquiring into the possibility of establishing a “ Close Time ” for the protection of indigenous animals, and for watching Bills intro- duced into Parhament affecting this subject ...............000. Report of the Committee, consisting of Jamus R. Naprer, F.R.S., Sir W. Tuomson, F'.R.S., W. Froupn, F.R.S., and Ossorns Reynotps (Secre- tary), appointed to investigate the effect of Propellers on the Steering of Vessels, (Plate Pye... cu. cee eh ces kat oes oe On the Investigation of the Steering Qualities of Ships. By Professor OssonnE REynorpe 580. 220 OES. DI oe ee Seventh Report on Earthquakes in Scotland, drawn up by Dr. Bryce, F.G.8., F.R.S.E. The Committee consists of Dr. Brycr, F.G.S., Sir W. Tuomson, F.R.S., J. Broven, G. Forsus, F.R.S.E., D. Minnz-Home, BVRS.By end P.DRuaa0onn «..s....4 .s oie ey ene hha Byoyat 8 "ey eel coo Ao nw seam Fourth Report of the Committee, consisting of Sir Jonn Lussocr, Bart., Prof. Presrwicu, Prof. Busx, Prof. T. M‘K. Hueuns, Prof. W. Boyp Daweins, Prof. Mratt, Rev. H. W. Crossxkzy, and Mr. R. H. Trppz- MAN, appointed for the purpose of assisting in the Exploration of the Settle Caves (Victoria Cave). Drawn up by R. H. Tippeman, Reporter Report on Observations of Luminous Meteors during the year 1875-76, by a Committee, consisting of James Grarsuer, F.R.S., R. P. Gree, F.G:S., F.R.A.S., C. Brooxz, F.R.S., Prof. G. Forsus, F.R.S.E., Wat- TER Frieut, D.Sc., F.G.S., and Prof. A. S. Hurscrut, M.A., F.R.A.S. oy LA) GEES SARI I iOS OAPI ARI ERR St 2 5A ei da ita hehe Report on the Rainfall of the British Isles for the years 1875-76, by a Committee, consisting of C. Brooxn, F.R.S. (Chairman), J. F. Bateman, C.E., F.R.S., Rogers Frevp, C.E., J. Guatsurr, F.R.S., T. Hawxstey, C.E., The Earl of Rossz, F.R.S., J. Suyrn, Jun., C.E., C. Tomurson, F.B.S., G. J. Symons (Secretary).............0008. Ninth Report of the Committee, consisting of Professor Everzrr, Sir W. Tuomson, F.R.S., Professor J. Cierxk Maxwett, F.R.S., G. J. Symons, F.M.S., Professor Ramsay, F.R.S., Professor A. Gurxre, F.R.S., Jams GuatsuEerR, F.R.S., Georer Maw, F.G.S., W. Pencetty, F.R.S., Pro- fessor Hurt, F.R.S., Professor Anstep, F.R.S., Professor Prestwicu, F.R.S., Dr. C. Lz Nrve Fosrmr, Professor A. §. Herscurt, G. A. Lz- sour, F.G.S., and A. B. Wrynn, appointed for the purpose of investi- gating the Rate of Increase of Underground Temperature downwards in various Localities of Dry Land and under Water. Drawn up by Rene PNERMIT, SECIELATY o>... 2 le see ea esie epoca eee es Nitrous Oxide in the Gaseous and Liquid States. By W. J. Janssen sc Vv Page 110 115 119 172 211 vi CONTENTS. Page Eighth Report of the Committee on the Treatment and Utilization of Sewage, reappointed at Bristol, 1875, and consisting of Ricwarp B. Grantuam (Chairman), C.E., F.G.S., Professor A. W. WiILLraMson, F.R.S., Dr. Grrzert, F.R.S., Professor Corrretp, M.A., M.D., Writ1am Hoprx, V.C., F. J. Bramwett, C.E., F.R.S., and J. Wotre Barry, C.E. 225 Improved Investigations on the Flow of Water through Orifices, with Objections to the modes of treatment commonly adopted. By Prof. James Tomson, LL.D., SBOE otod aisles eae Sys dh ccnp eeee 243 Report of the Anthropometric Committee, consisting of Dr. Beppor, Lord ABERDARE, Dr. Farr, Mr. Francis Gauron, Sir Henry Rawtiryson, Colonel Lanz Fox, Sir Rawson Rawson, Mr. James Heywoop, Dr. Movart, Professor Rotteston, Mr. Harzrerr, Mr. Fettows, and Pro- Pee ere neve Na URINE, ose oo coos sre iie"d)s 6, + vee s £2 tut we eect ee 266 On Cyclone and Rainfall Periodicities in connexion with the Sun-spot Periodicity. By Cutz Mirmeve |... 2... Eee 267 First Report of the Committee, consisting of Dr. Journ, Prof. Sir W. Txomson, Prof. Tarr, Prof. Batrour Srewart, and Prof. Maxwett, appointed for the purpose of determining the Mechanical Equivalent GEERT Ee Poe tee ea MME hI: Or SUR) ike ait er 275 Report of the Committee appointed for the purpose of promoting the extension, improvement, and harmonic analysis of Tidal Observations. Consisting of Sir Wirt1am Tuomson, LL.D., F.R.S., Prof. J. 0. Apams, F.RS., J. Orpnam, Witr1am Parxes, M.Inst.C.E., and Admiral Ricuarps, R.N., F.R.S. Drawn up by Sir Wit11am THomson...... 275 Third Report of the Committee, consisting of Dr. Brunton, F.R.S., and Dr. Pyz-Suirn, appointed to investigate the Conditions of Intestinal Secretion and: Movement) i. .2 0.00.3. c5. once th oot oe eee 308 Report of the Committee, consisting of A. Vernon Harcourt, Professor Gxapsrone, and Dr. Arxryson, appointed for the purpose of collecting and suggesting subjects for Chemical Research .................. 314 CONTENTS. NOTICES AND ABSTRACTS OF MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS. MATHEMATICS AND PHYSICS. vil Address by Professor Sir WILLIAM Tomson, LL.D., M.A., F.R.S., President = SALE AE SIPLDHT TRL 2 ee RP Tae ee ee ele er aes MatTHEMATICS. M. Vatentino Cerruti sur les Mouyements apériodiques des Systémes de eA ALOLIONS, 6 «ics x nisient ys, 00a sclclolS\aaferelelaialy © sisi sly 0 nip 4,< eine sais o a iansa 5 Lan Luret Cremona sur les Systémes de Sphéres et les Systémes de DITTGE donaece Qoob ORBE RSE POSE nO en Ten OU Se nm rnnvEr carchaotocne Mr. GeorcE H. Darwin on Graphical Interpolation and Integration ...... Mr. J. W. L. GuatsHER on certain Determinants ...........0. cere e eee nee —_—_—_____—_—_——_ on a Series Summation leading to an Expression for the Theta Function as a Definite Integral ......... ccc eee eee e ee eee Mr. W? Havpen on Parallel Motion 2.00. ccc. co.cc eee ete teeta e ce eenes Mr. Henry M. Jerrery on Plane Cubics of the Third Class with a Double eis Sancle Focus 5... AEG 6) PRT Ghats Selle oe ad Hale TENG satel eres Geta Cyclich AKC. 45:5). syetd el siae raya lee S wes Speed ea ls fs s1¥9 siereraiore sinisievesiwere Professor GrusEPPE June on the Inverse Problems of Moments of Inertia and GIAMOMENLA OL RESISLATICO: § Se cries cfeje cha aroieiore b -fore olay cies aiWiele wa oPal sie on the Graphical Representation of the Moments Gi Resistance of Plane igure)? . (hs). ce tle ile d ols olelele eile. cre-e-erereseteierneimnenne —$___—___—_—__—_ 0 a new Construction for the Central Nucleus of BRPAMeRSCCHION. mj wie lstausielvisley clare Siv\eleis apale ctersytie o)-taiel> o(o% sieleiwielJele ok Professor A. B. W. KenNEpDy on Centroids, and their Application to some Pepehanical ETO bleHIS 312.1 PIGS F.2d oF/> Professor P. G. Tarr on General Theorems relating to Closed Curves ...... Professor James THOMSON on a Theorem in the Mensuration of certain Solids Mr. W. H. WateEnn on Division-remainders in Arithmetic................ Mr. M. M. U. Wizxinson on Many-valued Functions ................+365 GENERAL Puysics, &e. Dr. James Croxt on the Transformation of Gravity...........eseee eee es My. Writ1am Crooxes on the Influence of the Residual Gas on the Move- MEE MCML CMF ACAGIOLOD sxiceack grike tis stain evs wav 8s FS") weep ele bs Ge 0 a + ogorcy 12 19 vill CONTENTS. Mr. W. Frovupr's Mechanical Theory of the Soaring of Birds ............ Professor F, Gururiz and Dr. F. Gururie on the Passage of Fluids through iCanllany and other Taber nts site h cts «sist hele aveeietel eet tg ets Mela ole is kee ta Professor J. PursER on the Modification of the Motion of Waves produced by Inlet LI tiie Saas os OGado aeRO one a. CUoremeMIOR oir KGeo Sanco Lord Rayxereu on the Forces experienced by a Lamina immersed obliquely TH ELA Lisi aeer ie Ao OGBOrn Sec C OU USOOOOENGON OOSRN TO Toes occ occ ad Professor OSBORNE REYNOLDS on the Resistance encountered by Vortex es and the Relation between the Vortex Ring and Stream-lines of a Disk Ce Dr. C. W. Strmens’s Description of the Bathometer ............+++eeeee Mr. G. Jonnstonr Sroney on the Amplitude of Waves of Light and Heat . on Acoustic Analogues to Motions in the Mole- GILES Old GLDRCN seetene ciavpninsolele ove n'< soso 7e(ahela\a eis\e7s 6. esos slats oforcie ere, ots aammenaneae Professor JamEs THomson on the Origin of Windings of Rivers in Alluvial Plains ee —_—_—__———_——_———_ on Metric Units of Force, Energy, and Power, larger than those on the Centimetre-Gram-Second System . Sir W. Taomson on the Precessional Motion of a Liquid................5: on the Laws of the Diffusion of Liquids ................ ——__-—————_ on a new case of Instability of Steady Motion............ on the Nutation of a Solid Shell containing Liquid Cc ) Lieut anp Hear, Captain ABNEY’s Photometric Measurements of the Magneto-electrie Light . Mr. J. T. Borromiery on the Conductivity of Heat by Water Mr. Howarp Gruss on the Testings of Large Objectives ..............4. on Recent Improvements in Equatorial Telescopes siete ——_—_—____—_—_——_ on a Method of Photographing the Defects in Optical Glass arising from want of Homogeneity Professor HENNEssy on the Decrease of Temperature with Height on the Barth's: Srtrfinee 4c ia..teis = a6 kteyie & ae aie bl afaik «lal le REP wwe Ss daranepnet er ee —_—_—_—_—__——— on the Distribution of Temperature over the British 1 Cuil ee ae AOA MOR hints 05 SAO acre Oo. So Soe Dr. J. JANSSEN sur les Usages du Revolver Photographique en Astronomie et en Biologie Pa a es ere | | Beem eee ew re ew em ere eee eee eee ee eeee eee eee ee eee evneeeree , Photographies du Passage de Vénus a Kobé sut le Mirageen: Mer 17 Mimic’ ciate Wil tald Osteen on Solar Photography, with reference to the History of the er 2d on the Eclipse of the Sun observed at Siam in April 1875 Mr. Jonn Kerr on Rotation of the Plane of Polarization by Reflection from a Magnetic Pole. istics. fet aes ei Pe hs ES DUR dee ae ek Mr. W. Lavp’s Description of Spottiswoode’s Pocket Polarizing Apparatus . . Professor G. G, SroxEs on a Phenomenon of Metallic Reflection ee | Solar Surface ELECTRICITY. Professors AyRTON and Perry on the Contact Theory of Voltaic Action.... Professor J. Dewan on a new Form of Electrometer .........eeeeeeeeees Mr. Oxtvrr J. LopcE on a Mechanical Ilustration of Electric Induction and Conduction ..... 4 Cees en eweneesee nes ete a ee es 6 8 5 8 8 is « 0 lw 8 wim me ey eee mena Oe ia ee ae ee eM a CT CNT ICN et Yer ose Wert ee ee tee ec CONTENTS. Professor J. Clerk MAxwELt on the Protection of Buildings from Lightning Sir W. THomson on Compass Correction in Iron Ships .........0++00005+ —_—— on Effects of Stress on the Magnetization of Iron ........ on Contact Electricity ........ cc eset cece eee e ener eens Acoustics. Mr. R. H. M. Bosanquet on the Conditions of the Transformation of Pendu- lum-Vibrations; with an experimental illustration .....-...+.seeeeeees Mr. Cotrn Brown on true Intonation, illustrated by the Voice-Harmonium SAG GITAL PINGOT-DOATO o..0.5 2 oe sees oo eye nels ote ob 00 08 009 050 feline oases Sir W. Tomson on a Practical Method of Tuning a Major Third.......... InstrRUMENTS, &e. Professor BARRETT on a Form of Gasholder giving a uniform Flow of Gas .. —________——_ on the new Lecture-Table for Physical Demonstration in the Royal College of Science for Ireland........... cess eee ee eee eeees —_—_—_— on two new Forms of Apparatus for the Experimental Illustration of the Expansion of Solids by Heat ............ceeeeeeeeees Mr. C. H. Gowrneuam on a Modification of the Sprengel Pump, and a new PBNep ra L AV CMU LAT evs lan, afeh ain o1ta\ pele 0 =: 610id, 01% 9ps)ere, viele as vials vices ns «06 Professor HENNESSY on new Standards of Measure and Weight............ Mr. G. J. Symons on a new Form of Thermometer for observing Earth Tem- PCTAGUTC. 00 cece rear e eee tetie cscs een eeeneneseteseseresssneses == on an Unmistakable True North Compass ,............. Sir W. THomson on a new Form of Astronomical Clock with Free Pendulum and Independently Governed Uniform Motion for Escapement-wheel .... we W. H. Wateyn on Mr, Sabine’s Method of Measuring small Intervals of TAS nc me pipe Gol, MACON IRIS BOR. CIIDIEI Ino REDO RCIrOM a cantar Kostner Captain A. W. Barrp on Tidal Operations in the Gulf of Cutch by the Great Trigonometrical Survey of India ......... ce esse cece eee e eee e ne en tenes Sir W. Tuomson on the Physical Explanation of the Mackerel Sky ........ — on Navigational Deep-sea Soundings in a Ship moving at REECE fahsnars ss Cesena k vic LOSE Fee seins PPM le ee tieteta SA Hele CHEMISTRY. Address by Mr. Witt1am Henry Perky, F.R.S., President of the Section . Mr. F. H. T. Atuan on a Safe and Rapid Evaporating-pan..............+- Mr. J. Banxs on Sewage Purification and Utilization ...........-eeeee eee Mr. H. W. Biaes on a new Voltaic Battery ........ 0. cece eee eee eens Professor Crum Brown on the Action of Pentachlotiile of Phosphorus on MEINEM re ec sei ete Seca set Se ttcaeee nx: Seven nett sees Mr. James T. Brown on Anthracene-testing ....... 2... eee ee eee teers Mr. J. Y. Bucuanan on some Instruments used in the ‘Challenger’........ Dr. Cameron on Ammonic Seleniocyanide.............+++ She Hoetbe Bae Mr. J. J. Conreman on a Gas-condensing Machine for the Liquefaction of Gases by combined cold and pressure, recently employed in the manufacture of Volatile Liquid Hydrocarbons ........ sce c cece eee ene een ee eeees on the Chemical Treatment of Town Excretion........ Professor Dewar on the Transformation of Chinoline into Aniline........-- Mr. W. Ditrmar on the Proximate Analysis of Coal-Gas.—Remarks on Reboul’s Paper on Pyro-Tartaric Acid ..... 6... esse eee eee e enn e entree ix Page 45 xX CONTENTS. Mr. E. M. Drxon on an Apparatus for the Analysis of Impurities in the Atmo- BPD ele oc os ee os ome oie wimps mld ginyei di ey4)e 010 e/xinpe aes mis. ye) mien’ vies aimsinaianatal ace Mii em oNINA CHIE (On Bire- Tielke. BF 5s «sare eisleya tela tewitheid om avannelenemnaee Mr. A. Fencusson on White-Lead.. «. . . 0.0 sin. oleic e sale e200 ne masnie sieninn Professor GAMGEE on the Physiological Action of Pyro-, Meta-, and Ortho- phosphoric ACiHIs .... iia. oe ons scien seco nec on sos ais malsin en od euemininpieiet: Professor GLADSTONE on the Influence of the Condition and Quantity of the Negative Element on the Action of the Copper-Zine Couple Proiessor COME ON SOL! WaleL. sisc:.> <> o,+ +o vajr oc sie'* »'s-eiblerie ene Mr. W. N. Hartrey on the Critical Point of Liquid Carbonic Acid in Minerals Mr. Witt1aM Henverson on the History of Copper-extraction by the Wet Way Colonel Horr on the Purification of the Clyde ...........0. 0. ceeeeeeeeee Mr. Cuartes T. Kiyezerr on the Limited Oxidation of Terpenes.—Part IV. Mr. A.C. Lerrs on two new Hydrocarbons from Turpentine Mr, J-Marrean‘on Soda Manufacture 0. OD Se os atv eon steele sim Dr. Macvicar on the possible Genesis of the Chemical Elements out of a Homogeneous Cosmic Gas or Common Vapour of Matter...........+.... Mr. M. M. Partison Murr on Essential Oil of Sage.—Part I]. ..........-. ———— on the action of Dilute Saline Solutions upon on certain Compounds of Bismuth............ Mr. J. A. R. Newxanps on Relations among the Atomic Weights of the Elements Pe ee ee COC eC et CC eC Te aT A ee Te er Ya a er et wD yee re ea Mr. T. L. Parrerson on Sugar Mr. W. H. Perxrn on some new Anthracene Compounds Dr. Witt1aM Ramsay on Picoline and its Derivatives ...............00005 Dr. J. Emerson Reynoups on Glucinum, its Atomic Weight and Specific FEL Bib cogereisiete & cd aNe nays. 0075 ote ake palo me nnTeMe MEN Te aeetelots acacia ia (ale sn Mr. W. C. S1tixar on the Utilization of Sewage ............cce cee eeeee Mr. R. D. Sizva on the Action of Hydriodic Acid on mixed Ethers of the General Formula Cy,H2,+1+0.CH3 Ma. ANDERSON SMITH On) SOG! 2% b avelebocmehetatme nee iat le wlbie\ ai el etuip a 163 Mr. J. A. WanKLYN on the Effects of the Mineral Substances in Drinking- Water on the Health of the Community ........... ccc cece eee eee 163 ANTHROPOLOGY. Mr. ALFRED RusseL WALLACE’S Address ..... 0.00 cece cece cee eens 100 General Sir J. ALEXANDER on the Oldest Woman in Scotland ............ 164 Professor BARRETT on some Phenomena associated with Abnormal Conditions VLG sch FOROS D6 OCEREG BE MOLISE CCG ERENCE oc oi ci RORRBEEOg OCIS ET oat 164 Mr, A. W. Buckxanp on Primitive Agriculture ..........ceeeenecnneees 164 Rey. Mr. CamEron on the Relation of Gaelic and English........ anowoebe 164 _ My. Hype Crarxke on the Prehistoric Names for Man, Monkey, Lizard, &c. . 165 -———— on Hittite, Khita, Hamath, Canaanite, Lydian, Etruscan, Sees ae ri READ VER MAC ATTN Os ec oli akal ak oh nigh o sy =, #14 [68 VS) cuainy Sele exohs ny 9js) ta) aya,si ola. aiat» 165 Professor CLELAND on a Sooloo Skull ....... cee cece ce eee eee teen eet 165 Mr. C. O. Groom Napier on the Pheenicians...........00e eee se ee eeeeees 165 Mr. W. Harper on the Natives of British Guiana ......... RETR Bt gicdew 165 Mr. J. Park Harrison on the Eastern Picture-writing .......6...0ee0 ees 165 X1V CONTENTS. Page Mr. Bertram F, HarrsHorne on the Rodiyas of Ceylon .......-...-s00s 165 Gopi J. 8. Hay and Commander Cameron on Horned Men of Akkem, in 711 St) hie GRIGIO ROL EOE OIRO MRO OI 200 5.0.0 62> Oc Mr. H. v. Humpotnr v. p. Horcx on the Laplanders and People of the North ae Mimrope ss. PPE eae eee bein dade cise ee es 06 vee els eng a nee 166 Mr. W. J. Know tes on the Classification of Arrow-heads .............+4. 166 on the Find of Prehistoric Objects at Portstewart...... 166 Dr. Kwox on Bosjes Skulls. 0.1.0.0... eee eee ee een ee cee ene e ees , 166 Rey. J. M‘Cawnn on the Origin of Instinct ......... cscs e enters ence 166 Mr. Hector MacLean on the Gaelic Inhabitants of Scotland ............ 166 —. on the Anglicizing and Gaelicizing of Surnames .... 167 Mr. Kerry Nicuots on Explorations in the Islands of the Coral Sea........ 167 Mr. W. PENGELLY on an Urn from Chudleigh, Devon..............00000- 169 My. J. S. Poené on Relics of Totemism in Scotland in Historic Times ...... 169 ——_____———— on the Arthurian Apple and the Serpent of the Ancients .. 169 Mr. James SHaw on Right-handedness ........0..cseccesccvercesereers 169 —— on the Mental Progress of Animals during the Human 12H) GONE Ge aROp HO Src Gee RT occlu oaciomao oon sonvor 169 Dr. ALLEN THoMSoN on two Skulls from the Andaman Islands............ 169 GEOGRAPHY. Address by F. J. Evans, C.B., F.R.8., Captain R.N., President of the Section 169 Mr. A. BowpEn on a new Route to the Sources of the Niger.............. 181 Mr. J. Y. Bucuanan on the Specific Gravity of the Surface-water of the Ocean, as observed during the Cruise of H.M.S. ‘Challenger’ .................. ———_—_—_—— on a new Deep-sea Thermometer...............s000- 181 Commander VY. L. Cameron on his Journey through Equatorial Africa .... 181 Signor G, E. Cerruti on his Recent Explorations in N.W. New Guinea.... 182 Lieutenant W. H. Curprenpauu on the White Nile between Gondokoro and BA DPUGGO. soe oie cois,2.0.0,0soveayeueqtste oan (ove i0aejcyeteue peeve eae It aELapy eee eee 182 Mr. W. Barrineton D’Atmerpa on Perak and Salangore..............+. 182 Mr. SanpFoRD FLEMING on the Conventional Division of Time now in use, and its Disadvantages in connexion with Steam Communications in different ae of the World ; with Remarks on the desirability of adopting Common ime over the Globe for Railways and Steam-Ships..........++eesseees 182 Professor ForBEs on the Site of the Grave of Genghiz Khan .............. 182 Dr. Lirron Forsss on the Samoan Archipelago ............eceeeeeeeeee 183 Captain J. S. Hay on Akem and its People, West Africa ............006- 183 Mr. J. Murray on the Geological Distribution of Oceanic Deposits ........ 183 Mr. Kerry Nicuots on the Islands of the Coral Sea .........+.seeeee eee 183 Rey. J. Paterson on a Journey across Finland, from Ellenborg to Archangel VME TROMT She is oe od dadae ven ¢ ouiegls «> «oe Ee eae ee Colonel R. L. Prayrarr on Travels in Tunis in the Footsteps of Bruce...... 183 Professor PorTER on some Points of Interest in the Physical Conformation and Antiquities of the Jordan Valley ./i.\ 00... adiee aus cae oe Mr. A. Stuson on the River Putumayo or Ica, South America ..........+5 184 Mr. Octavius Stone on his Recent Journeys in New Guinea...........++- 184 Staff-Commander Tizarp on the Temperature obtained in the Atlantic Ocean during the Cruise of H.M.S. ‘Challenger’ ........0.scseceueeuceeeues . 185 CONTENTS. XV ECONOMIC SCIENCE ann STATISTICS. Page Address by Sir Grorgr CamPpBeELt, K.C.S.1., M.P., D.C.L., President of the # ERNMENT cs ogc cP-r as cd acl cior els ger ees] saa ok 1a «400 sce Sle eyolni ates « « 186 Mr. Wii11am Borty on Agricultural Statistics...........0.cceeeeereeees 194 Rey. JoHn 8. Burt on the Economy of Penalties.............00eeee eee 195 Rey. Aaron Busacorr on the present extent of Slavery and the Slave Trade, with a reference to the Progress of Abolition since the close of the American Mr. ALEXANDER M‘NeEEx Carrp on some Special Evils of the Scottish Poor + ne ding eet RRS ge Slat ABP UE BIS Sieg testers Seemann e 197 Mr. Hypr Cxiarxke on the part in the Operation of Capital due to Fixed or iimmited Atniounts invested In Trade. oo. ec ews cee s eee awn wie we we vem Mr. St. Joun V. Day on recent attempts at Patent Legislation............ 198 Dr. W. Nertxson Hancock on the Importance of extending the British Gold Standard, with subordinate Silver Coins, to India as a remedy for the incon- venience in India of a rapid Depreciation of Silver ..............200005 198 on Savings’ Banks as a State Function developed by Charity Organization ee Mr. J. Heywoop on the Memorial of Eminent Scientific Gentlemen in favour of a Permanent Scientific Museum .............ccce cece eeceees 199 Dr. Wri11Am Jack on the Results of Five Years of Compulsory Education . 200 Mr. Henry JEPHSON on the Valuation of Property in Ireland Mr. W, Jotiy on Physical Education and Hygiene in Schools ............ 207 Rey. Dr. M‘Cann on the Organization of Original Research Don ArtuRO DE MARcoartu on Spanish Mining Mr, StepHEN Mason on the Depreciation of Silver and a Gold Standard for eT era 8 cro ons. So WRU AAS MALE ELM tL, AOA ok oot 207 Mr. J. MarHxson, Junr., on the Silver Dilemma ............. 0. cece eee ee 207 Mr. R. W. PircHer on Overcrowding in Liverpool ..............0e eee eee 208 Rey. W. Ross on the Educational Value of their Native Language to the Gaelic-speaking Population of Scotland ............. 0. cece eee eee eee 208 Mr. F. RusseExu on Sheriff Courts and Relative Judicial Statistics ........ 208 _ Mr. JAmus StEPHENSON on the Civilization of South-Eastern Africa ...... 208 “ig ta Tarr on the Theory and Practice of Accident Insurance by Sea and MEN ec xtc ordioy 9 Se vin ne POON POA Sr Ot) 2 A EIT OES, Mr. W. Tutxack on the Boarding-out of Pauper Children in England...... 209 Rey. R, THomson on the Prevention of the Pollution of Rivers............ 210 MECHANICAL SCIENCE. Address by CHarLtes W. MrerrirFiecp, F.R.S., President of the Section .... 211 Major BEAumont on the Removal of Subaqueous Rocks by the Diamond PHS DOTCE. Caw he ath crepsdeadts ary oniil Chibeds oboe ate tld obs oa le ates 219 _ Mr. M. Bereeron on the Removal of Sand-bars from Harbour-mouths .... 219 Mr. J. B. Beynon on a Hand-machine for Shaping and I"inishing Metal Sur- at. Jenyeovec neice clei DOR ESTES UENO EPR = ce ee i wt 219 Mr. A. B. Brown on a Flanging-iron and Steel Plates for Boiler purposes .. 219 -———_—— on an Engine for Starting and Reversing large Marine Teen ith hie rele cuelaieis atels eneinnete nents 220 Mr. Tuomas Doxsson on Improved Safety-Apparatus for Mine-Hoists and AVVO HO UBS = WIPES Tacers ie ack vdieiei a's Sw TEMA AN *M SAO “CEB OL ysn3ny ‘nITEOAG “ay ‘puepiy jo tesoy “uOIgsy ‘MORLEY “YW AA a wee e eee ceeees BODO RD OMDOODCOS SN tah “oar ‘umozueuxg pytilery CSP eae ICOGO GO SIO Ca (1 ‘qAO1T LSOAOUd ‘AAU UL Ae ree a DADEISE QBbS san onensen eh p's ‘ dag ‘HounaNiag TSU ‘99g ‘uosurqoy uyor xg oipieais sleinleiemiaie 7 tees eCrE uOsMIqoY “yy “I, “AO ee ee ‘O39 OO BTS U'a ‘seqiog sossayo.. ieee i aiacoieiWiesais’ are aaipia/eie piuisYafars/e''e/a no PS em Soe Case mie ‘aA BT saa Qz0 1oBEaFOIg OF SUA MT PEC NS | or-o-g “g'O'M ‘ANVESIU@ TIVONOGOVN “L UIS ie hase. ‘ ‘SW TaMoT At TM TAD (ttt tot etee ce ceee een eens teens ees egary forts oa ‘aoyeq uyor *SESl ‘es aune ‘a9 aIuaNvgo Ss 5 a S'l'd ‘wh AO[SUa JOssajorg *AQY we enee eee eee eee eee eee a ‘oy ‘tefoxy rawW0UOIsY Cyse Wa ‘Kary * a‘) } ‘SDAA “oma WH ‘SIOIMDACAS WVYayV "ADU auL IR “sud “wit ‘WeMod JOSSIJOIg "ANG “tte Se eanecucceussanne "00g *[094) ‘sarg og Wa Tomer AA "MA ‘AT "ZEST ‘6 aune ‘aqu0axo Oy “Saad “aw ‘Auoqneq sossajoig Urtstettt tt: slain sisla\a’s\ais piale/= Sum Sexy Rory y 1 ‘Sud ‘lajsmoig piaeg ag JS *‘o2p “soa “sud “a'd ‘ANVINONG ‘AM “AGH WL SDA SU WW “SUM TOSsOJOI | oo... eee e eee seen ee eee rena tans "Les ‘2g tequioydag “Huo ‘sp’ “unt ‘Avi mAh S'O'a “SU “VI GmooseH vou, “Ay “soy { 28 “S'D a “SW eee GAYVTTEM Zhe TUVA UL “SAlINWLAUDAS TVWSOT “SLNAGISSUd-35IA “SLN3dISAdd *JUIWIIMIUIULOY) SHI WOT ‘SOLIVJO1IIG [eo0ry pue ‘sqUapIsalg-ad1 A. ‘syuapIsad 7 (ata ‘MolyelI0ssVy Ystylig 9} Jo SUI} TN jo sowiy, pue svov[q 9} SUIMOYS IqRL DODOEIOCIDGORNTY ia fay *£T]94995 IOSSIJOLT ‘S'U'a *sd901S *x) '4) IOSSaJOIg wee ee eee “SW Wd OWI ‘Sad “a'd ‘uosurqoy ‘se | A *UOsTTAL “d ‘A\ TOSSazoIg pie COMO h SUH L ‘gZaT[0D s,usent ALGER “ag ‘hiuay *S *g “Ad "Zest ‘1 soquiajdasg ‘isvaTag "GW “SSDs OUI 4 ene eee es ewen scans WT CO' ‘SHOU prepay aay borers tres esters esse trereses faara0g [ekoy U3 JO “d'A ‘bsq ‘ually "0 “f “AN : sreseeeresees -Qureg ayoag vl aq ‘1, Arey stg | 7B ‘svar ‘Aroq ury [AOU ‘ANIAVS CUVMGG TANOTOO, seeee WEI Ata “SW ‘sold “Whew ‘assoy jo peg aL nO i i i icy aT ae | “To” ‘ual[Tystuug jo eq ou, ) dee i trencreceseesceeeees beg ‘mr9989 MA a “DL My W “bsq ‘ Ploqqop "1 rd . shag i ee a ain “qaeg “UOJ@TPPLA “A AMET TS SU “g1eg “neapiog ‘a uyor 1s *rsst ‘g Amp SHOIMSAT aU bag ea ioe a(ane eferuceieiate7einietexeierel tieraleisie scary “S°T'al SWI ‘MOpSUIHT LOSsOJOIg tag Lot ert teers tect cece cere ereeeseencseeeers Tefoay JOTIOU Sywa “bsa Kepy sopty ea ER ease “Sard OWA “yoraspag Jossajorg “Aa | -ONSV “Saad “T'O'd “bsa ‘AUIV ITAACGIA ADUOAD . 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Belfast 1858. Hull seen eneee 'G. B. Greenou ‘Prof. Jameson ete eees ch, F.RS. . eens ; PRESIDENTS AND SECRETARIES OF THE SECTIONS, XXX1il Date and Place. Presidents. | Secretaries. GEOLOGICAL (ann, untiz 1851, GEOGRAPHICAL) SCIENCE, COMMITTEH OF SCIENCES, III.—GEOLOGY AND GEOGRAPHY. 1832. Oxford ....../R. I. Murchison, F.R.S. .......4. John Taylor. W. Lonsdale, John Phillips. , Prof. Phillips, T. Jameson Torrie, Rey. J. Yates. SECTION C.—GEOLOGY AND GEOGRAPHY, graphy. R. 1. Murehison,F.R.8. graphy. G.B.Greenough,F.R.S. iC. Lyell, F.R.S., V.P.G.S.— Geo- graphy. Lord Prudhope. ‘Rev. Dr. Buckland, F.R.S.—Geo- Charles Lyell, F.R.S.— Geogra- phy. G. B, Greenough, F.R.S. H. T. De la Beche, F.R.S.......... R. I. Murchison, F.R.S. ........ Richard HE. Griffith, F.R.S., M.R.L.A. Henry Warburton, M.P., Pres. Geol. Soe. Rey. Prof. Sedgwick, M.A., F.R.S. Leonard Horner, F.R.S.— Geogra- phy. G. B. Greenough, F.R.S. Very Rey. Dr. Buckland, F.R.S. ... Sir H. T. De la Beche, C.B., F.R.S ‘Sir Charles Lyell, F-R.S., F.G.8. Sir Roderick I. Murchison, F.R.8. graphy. G.B.Greenough,F.R:S.| Torrie. Liverpool... Rev.Prof. Sedgwick, F.R.S.— Geo- Captain Portlock, R. Hunter.—Geo- graphy. Captain H.M. Denham,R.N. \W. C. Trevelyan, Capt. Portlock.— Geography. Capt. Washington. 'George Lloyd, M.D., H. EH. Strickland, 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. JE. W. Binney, R. Hutton, Dr. R. Lloyd, H. BH. Strickland. (Francis M. Jennings, H. E. Strick- land. \Prof. Ansted, E, H. Bunbury. Rey. J. C. Cumming, A. C. Ramsay Rey. W. Thorp. Robert A. Austen, J. H. Norten, M.D., Prof. Oldham.— Geography. Dr. C. T. Beke. Prof. Ansted, Prof. Oldham, A. C. Ramsay, J. Ruskin. Starling Benson, Prof. Oldham, Prof. Ramsay. J. Beete Jukes, Prof. Oldham, Prof. A. C. Ramsay. A. Keith Johnston, Hugh Miller, Prof. Nicol. SECTION ¢ (continued).—GEOLOGY. 1851. Ipswich .../ William Hopkins, M.A., F.RB.S... Lieut.-Col. Portlock, R.E., F.R.S. Prof. Sedgwick, F.R.S. .......0.6+- 1854, Liverpool . ./Prof. Edward Forbes, F.R.S. ....John Cunningham, Prof. Harkness, C. J. F. Bunbury, G. W. Ormerod, | Searles Wood. James Bryce, James MacAdam, Prof. M‘Coy, Prof. Nicol. Prof. Harkness, William Lawton. G. W. Ormerod, J. W. Woodall. i 7: * At a Meeting of the General Committee held in 1850, it was resolyed “That the subject of Geography be separated from Geology and combined with Ethnology, to consti- tute a separate Section, under the title of the * Geographical and Ethnological Section,” for Presidents and Seeretaries of which see page xxxvii. 876. c REPORT—1876. 1832. Oxford . Hxeter . Belfast . Glasgow ... . Cheltenham sence . Manchester 2, Cambridge . Newcastle . Su otter Obe 5, Birmingham . Nottingham . Dundee . Norwich . . Liverpool... . Edinburgh... . Brighton ... . Bradford .. . Glasgow ... Presidents. Sir R. E, Murchison, F.RS. . Prof. A. C. Ramsay, F.R.S. .... The Lord Talbot de Malahide . William Hopkins, M.A., LL.D., E.R.8. Bs eo ee Lyell, LL.D., D.C.L. Bee Biot Sedgwick, LL.D., E.RBS., S. Sir R. aa “Murchison, LL.D., F.RB.S., &e. J. Beete Jukes, M.A., ERS eee ..|Prof. Warington W. Smyth, E.RS., F.G.S8. Prof. J. Phillips, LL.D., F.B.S., F.G:8. Sir R. I. Murchison, Bart.,K.C.B. Prof.A.C, Ramsay, LL.D., F.R.S. Archibald Geikie, F.R.S., F.G.S. D.C.L., ..|R. A. C. Godwin-Austen, F.R.S., E.G.S Prof. R. ‘Harknéss, E.R.S., F.G.S. Sir Philip de M. Grey Egerton, Bart., M.P., F.R.S. Prof. A: Geikie, E.R.S., F.G.S8.. R. A. C. Godwin-Austen, F.R.S. .|Prof. J. Phillips, D.C.L., F.RB.S., F.G.8 Prof. Hull, M.A., F.R.S., Dr. Thomas Wright, F.R.8.E., G F.G.S. Prof. John Young, M.D. ......... E.G.S8. Secretaries. —————— ..|James Bryce, Prof. Harkness, Prof. Nicol. ..|Rey. P. B. Brodie, Rev. R. Hepworth, Edward Hull, J. Scougall, T. Wright. ..|Prof. Harkness, Gilbert Sanders, Ro- bert H. Scott. Prof. Nicol, H. ©. Sorby, E. W. Shaw. ,/Prof. Harkness, C. Sorby. Prof. Harkness, Edward Hull, Capt. Woodall. Prof. Harkness, Edward Hull, T. Ru- pert Jones, G. W. Ormerod. Lucas oat Prof. T. Rupert Jones, H.C.8 E. F. Boyd, Fob Daglish, H. C. Sor- by, Thomas Sopwith. W. B. Dawkins, J. Johnston, H. C. Sorby, W. Pengelly. Rey. P. B. Brodie, J. Jones, Rev. E. Myers, H. C. Sorby, W. Pengelly. R. Etheridge, W. Pengelly, T. Wil- son, G. H. Wright. Edwar d Hull, W. Pengelly, Henry Woodward. Rey. O. Fisher, Rev. J. Gunn, W. Pengelly, Rev. H. H. Winwood. W. Pengelly, W. Boyd Dawkins, Rev. H. H. Winwood. W. Pengelly, Rev. H. H. Winwood, W. Boyd Dawkins, G. H. Morton. .|R. Etheridge, J. Geikie, J. McKenny Hughes, L. C. Miall. L. C. Miall, George Scott, William Topley, Henry Woodward. 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. Topley. Rey. J. Longmuir, FH. I. J. Armstrong, F. W. Rudler, W, Topley. BIOLOGICAL SCIENCES. COMMITTEE OF SCIENCES, IV.—-ZOOLOGY, BOTANY, PHYSIOLOGY, ANATOMY, Rey. P. B. Duncan, F.G.S. 1833. Cambridge */Rev. W. L. P. Garnons, ELS... ..(Rev. Prof. J. 8. Henslow. .|C. C. Babington, D. Don. 1834. Edinburgh |Prof. Graham W. Yarrell, Prof. Burnett. eer rrr * At this Meeting Physiology and Anatomy were made a separate Committee, for : Presidents and Secretaries of which see p. xxxvi. PRESIDENTS AND SECRETARIES OF THE SECTIONS. XXXV Date and Place: Presidents. Secretaries. SECTION D.—ZOOLOGY AND BOTANY. 1835. Dublin «..... Die Alltiianis: (iiectscdsidesdeccdeves J. Curtis, Dr. Litton. ; 1836. Bristol ...... Rey. Prof. Henslow ............065 J. Curtis, Prof. Don, Dr. Riley, 8. Rootsey. 1837. Liverpool ...|W. S. MacLeay ..csissssc.ssesceseee C. C. Babington, Rey. L. Jenyns, W. Swainson. 1838. Newcastle.../Sir W. Jardine, Bart:........ we... /J.E. Gray, Prof. Jones, R. Owen, Dr. Richardson. 1839. Brimingham|Prof. Owen, F.R.S. .......0....05. HB. Forbes, W. Ick, R. Patterson. 1840. Glasgow ...|Sir W. J. Hooker, LL.D .....:.... Prof. W. Couper; H. Forbes, R. Pat- terson. 1841. Plymouth...|John Richardson, M.D., F.R.S.../J. Couch, Dr. Lankester, R. Patterson. 1842. Manchester |Hon. and Very Rev. W. Herbert, Dr. Lankester, R. Patterson, J. A. LL.D., F.1.8. Turner. 1848. Cork .......:. William Thompson, F.L.S. ...,..|G. J. Allman, Dr. Lankester, R. Pat- terson. 1844. York......... Very Rey. The Dean of Manches-|Prof. Allman, H. Goodsir, Dr. King, ter. Dr. Lankester. 1845: Cambridge |Rey. Prof. Henslow, F.L.S. ....../Dr. Lankester, T. V. Wollaston. 1846. Southampton|Sir J. Richardson, M.D., F.R.S. |Dr. Lankester, T. V. Wollaston, H. Wooldridge. 1847. Oxford....... H. E. Strickland, M.A., F.R.S..../Dr. Lankester, Dr. Melville, T. VY. Wollaston. SECTION D (continued).—ZOOLOGY AND BOTANY, INCLUDING PHYSIOLOGY. [For the Presidents and Secretaries of the Anatomical and Physiological Subsections and the temporary Section E of Anatomy and Medicine, see p. xxxvii.] 1848. Swansea ;../L. W. Dillwyn, F\R.S. ............ Dr. R. Wilbraham Falconer, A. Hen- frey, Dr. Lankester. 1849. Birmingham) William Spence, F-.R.S............. Dr. Lankester, Dr. Russell. Prof. J. H. Bennett, M.D., Dr. Lan- kester, Dr. Douglas Maclagan. Prof. Allman, F. W. Johnston, Dr. E. 1850. Edinburgh. .|Prof. Goodsir, F.R.S. L. & E. ... 1851. Ipswich......{Rev. Prof. Henslow, M.A., F.R.S. Lankester. 1852: Belfast ..:... Wisc QBalboy” scessttistsrs cosetbareetdse Dr. Dickie, George C. Hyndman, Dr. ’ t Edwin Lankester. 1853. Hull ......... C. C. Babington, M.A., F.R.S..../Robert Harrison, Dr. E. Lankester. 1854. Liverpool ... Prof. Balfour, M.D., F.R.S....... Isaac Byerley, Dr. I. Lankester. William Keddie, Dr. Lankester. 1855. Glasgow .../Rev. Dr. Fleeming, F.R.8.E. ... 1856. Cheltenham ./Thomas Bell, F.R.S., Pres.L.8..../Dr. J. Abercrombie, Prof. Buckman, Dr. Lankester. 1857. Dublin ...... Prof. W.H. Harvey, M.D., F.R.8./Prof. J. R. Kinahan, Dr. E. Lankester, Robert Patterson, Dr. W. E. Steele. 1858. Leeds......:.: C. C. Babington, M.A., F.R.S.....Henry Denny, Dr. Heaton, Dr. E Lankester, Dr. E. Perceval Wright. 1859. Aberdeen .../Sir W. Jardine, Bart., F.R.S.E../Prof. Dickie, M.D., Dr. E. Lankester, Dr. Ogilvy. 1860. Oxford ...... Rey. Prof. Henslow, F.L.S. ...... W. 8. Church, Dr. E. Lankester, P. | L. Selater, Dr. B. Perceval Wright. 1861. Manchester..' Prof. C. C. Babington, F.R.S. ...|Dr. T. Aleock, Dr. E. Lankester, Dr. P. L. Sclater, Dr. BE. P. Wright. 1862. Cambridge.../Prof. Huxley, FR.S. 0... Alfred Newton, Dr. E. P. Wright. 1863. Newcastle ...|Prof. Balfour, M.D., F.R.S. ....../Dr. E. Charlton, A. Newton, Rev. H. B. Tristram, Dr. E. P. Wright. 1864. Bath ......... Dr. John HE. Gray, F.R.S. ...... H. B. Brady, C. EB. Broom, H. T. Stainton, Dr. E. P. Wright. ..|Dr. J. Anthony, Rev. C. Clarke, Rev, ) H. B, Tristram, Dr. E. P. Wright. c2 = 1865. Birmingham /T. Thomson, M.D., F.R.S, . XXXV1 REPORT—1876. Date and Place. | Presidents. Secretaries. SECTION D (continued).—BIOLOGY *. 1866, Nottingham .|Prof. Huxley, LL.D., F.R.S.— Dr. J. Beddard, W. Felkin, Rev. H. 1867. Dundee 1868. Norwich 1869. Exeter 1870. Liverpool ... 1872. Brighton ... 1873. Bradford ... 1874. Belfast ...... 1875. Bristol...... 1876. Glasgow .. Physiological Dep. Prof. Hum- phry, M.D., F.R.S.—Anthropo- logical Dep, Alfred R. Wallace,| F.R.G:S. Prof. Sharpey, M.D., Sec. R.S.—, Dep. of Zool. and Bot. George Busk, M.D., F.R.S. ...,Rev. M. J. Berkeley, F.L.S.— Dep. of Physiology. W. H. Flower, F.R.S8. George Busk, F.R.S., F.L.S.— Dep. of Bot. and Zool. C. Spence Bate, F.R.8.—Dep. of Ethno. EH. B. Tylor. Prof. G. Rolleston, M.A., M.D., ¥.R.S., F.L.8.—Dep. Anat. and Physiol. Prof. M. Foster, M.D., F.L.S.—Dep. of Ethno. J. Evans, F.R.S. 1871, Edinburgh |Prof.Allen Thomson,M.D.F.R.S. —Dep. of Bot. and Zool. Prof. Wyville Thomson, F.R.S.— Dep. of Anthropol. Prof. W.| Turner, M.D. Sir John Lubbock, Bart., F.R.S. —Dep. of Anat. and Physiol. Dr. Burdon Sanderson, F.R.S. —Dep of Anthropol. Col. A. Lane Fox, F.G.S. Prof. Allman, F.R.S.—Dep. of | Anat. and Physiol. Prof. Ru-| therford, M.D.—Dep. of An-| thropol. Dy. Beddoe, F.R.S. | Prof. Redfern, M.D.—Dep. of | Zool. and Bot. Dy. Hooker, C.B., Pres. R.S..—Dep. of An- thropol. Sir W. R.Wilde,M.D. P.L.Sclater, .R.S.—Dep. of Anat. and Physiol. Prof.Cleland,M.D., F.R.S.—Dep. of Anthropol. Prof. Rolieston, M.D., F.R.S. |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. McKendrick,F.R.8.E.) B. Tristram, W. Turner, E. B. Tylor, Dr. E. P. Wright. C. Spence Bate, Dr. 8. Cobbold, Dr. M. Foster, H. T. Stainton, Rey. H. B. Tristram, Prof. W. Turner. Dr. T. 8. Cobbold, G. W. Firth, Dr. M. Foster, Prof. Lawson, H. T. Stainton, Rey. Dr. H. B. Tristram, Dr. E. P. Wright. Dr. T. 8. Cobbold, Prof. M. Foster, M.D., E. Ray Lankester, Professor Lawson, H. 1’. Stainton, Rey. H. B. Tristram. Dr. T. 8. Cobbold, Sebastian Evans, Prof. Lawson, Thos. J. Moore, H, T. Stainton, Rev. H. B. Tristram, C. Staniland Wake, E. Ray Lan- kester. Dr. T. R. Fraser, Dr. Arthur Gamgee, E. Ray Lankester, Prof. Lawson, H. T. Stainton, C. Staniland Wake, Dr. W. Rutherford, Dr. Kelburne King. Prof. Thiselton-Dyer, H. T. Stainton, Prof. Lawson, I’. W. Rudler, J. H. Lamprey, Dr. Gamgee, H. Ray Lan- kester, Dr. Pye-Sinith. 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. MceKendrick, Prof. W. R. MNab, Dr. Martyn, F. W. Rudler, Dr. P. H. Pye-Smith, Dr. W. Spencer. HK. R. Alston, Hyde Clarke, Dr. Knox, Prof. W. R. M‘Nab, Dr. Muirhead, Prof. Morrison Watson. ANATOMICAL AND PHYSIOLOGICAL SCIENCES. COMMITTEE OF SCIENCES, V.—ANATOMY AND PHYSIOLOGY. Dr. Bond, Mr, Paget. Dr. Roget, Dr. William Thomson. * 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. - 1846.Southampton|Dr. Pritchard 1851. Ipswich .../Sir R. I. Murchison, F.R.S., Pres. R.GS8 PRESIDENTS AND SECRETARIES OF THE SECTIONS, Date and Place. | Presidents. ei a a a XXXVli Secretaries. SECTION E. (UNTIL 1847.)—ANATOMY AND MEDICINE. 1835. Dublin ...... 1D Yad Berkel cts lial a eee - 1836. Bristol ...... Dr. Roget, F.R.S. ........scessseeee 1837. Liverpool ...|Prof. W. Clark, M.D. ............ 1838. Newcastle ...'T. E. Headlam, M.D. ............ 1839. Birmingham|John Yelloly, M.D., F.R.S. ...... 1840. Glasgow .../James Watson, M.D................ 1841. Plymouth .../P. M. Roget, M.D., Sec.R.S, 1842. Manchester ..Edward Holme, M.D., F.L.S. ... ..|Dr. J. Butter, J. Fuge, Dr. Dr. Harrison, Dr. Hart. Dr. Symonds. Dr. J. Carson, jun., James Long, Dr. J. BR. W. Vose. T. M. Greenhow, Dr. J. R. W. Vose, Dr. G. O. Rees, F. Ryland. |Dr. J. Brown, Prof.Couper, Prof. Reid. R. 8. Sargent. Dr. Chaytor, Dr. R. 8. Sargent. 1843. Cork ......... ‘Sir James Pitcairn, M.D.......... Dr. John Popham, Dr. R. 8. Sargent. 1844. York.........|\J. C. Pritchard, M.D. ............ I. Erichsen, Dr. R. 8. Sargent. SECTION E.—PHYSIOLOGY. 1845, Cambridge .|Prof. J. Haviland, M.D. ......... Dr. R. 8. Sargent, Dr. Webster. 1846. Southampton Prof. Owen, M.D., F.R.S.......... C. P. Keele, Dr. Laycock, Dr. Sargent. 1847. Oxford* ...|Prof. Ogle, M.D., F.R.S........... Dr. Thomas K. Chambers, W.. P. | Ormerod. PHYSIOLOGICAL SUBSECTIONS 1850. Edinburgh Prof. Bennett, M.D., F.R.S.E. 1855. Glasgow ...|/Prof. Allen Thomson, F.R.8. ... 1857. Dublin .....: 'Prof. R. Harrison, M.D. ......... 1858. Leeds ...... ‘Sir Benjamin Brodie, Bart.,F.R.S. 1859. Aberdeen .../ Prof. Sharpey, M.D., Sec.R.8. ... 1860. Oxford |Prof. G. Rolleston, M.D., F.L.S. 1861. Manchester. Dr. John Davy, F.R.S.L. & E.... 1862. Cambridge ..C. E. Paget, M.D. .............0664. 1863. Newcastle... Prof. Rolleston, M.D., F.R.S. ... 1864. Bath........ |Dr. Edward Smith, LL.D., F.R.S. 1865. Birminghmt. Prof. Acland, M.D., LL.D., F.RB.S. { OF SECTION D. Prof. J. H. Corbett, Dr. J. Struthers. Dr. R. D. Lyons, Prof. Redfern. C. G. Wheelhouse. Prof. Bennett, Prof. Redfern. Dr. R. M‘Donnell, Dr. Edward Smith, Dr. W. Roberts, Dr. Edward Smith. G. F. Helm, Dr. Edward Smith. Dr. D. Embleton, Dr. W. Turner. J. 8. Bartrum, Dr. W. Turner. Dr. A. Fleming, Dr. P. Heslop, Oliver Pembleton, Dr. W. Turner. GEOGRAPHICAL AND ETHNOLOGICAL SCIENCES. [For Presidents and Secretaries for Geography previous to 1851, see Section C, p. xxxiii.] ELHNOLOGICAL SUBSECTIONS 1847. Oxford...... Prof. H. H. Wilson, M.A. 1848. Swansea 1849. Birmingham 1850, Edinburgh.. eeeeee Vice-Admiral Sir A, Malcolm .. SECLION E.—GEOGRAPHY AN OF SECTION D, Dr. King. Prof. Buckley. G. Grant Francis. Dr. R. G. Latham. .(Daniel Wilson. D ETHNOLOGY. R. Cull, Rev. J. W. Donaldson, Dr. Norton Shaw. 1852. Belfast sewees Col. Chesney, R.A., D.C.L., E.R.S. R. Cull, R. MacAdam, Dr, Norton Shaw. Bs * By direction of the General Committee at Oxford, Sections D and E were incorporated under the name of “ Section D—Zoology and Botany, including Physiology” (see p. xxxv). ho Section being then vacant was assigned in 1851 to Geography. + Vide note on page xxxvi. XXvlli REPORT—1876. Date and Place. Presidents. Secretaries. UsiRe 18 hill lp spsaares R. G, Latham, M.D., F.R.8. ...|R. oo Rey. H. W. Kemp, Dr. Nor- ton Shaw. 1854, Liverpool.../Sir R. I. Murchison, D.C.L.,/Richard Cull, Rev. H. Higgins, Dr, FE.R.S. Ihne, Dr. Norton Shaw. 1855. Glasgow ...\Sir J. Richardson, M.D., F.R.S. |Dr. We G. Blackie, R. Cull, Dr. Nor- ‘ ton Shaw. 1856. Cheltenham |Col. Sir H. C. Rawlinson, K.C.B./R. Cull, F. D. Hartland, W. H. Rum- ; sey, Dr. Norton Shaw. 1857. Dublin ...... Rey. Dr. J. Henthawn Todd, Pres./R. Cull, 8. Ferguson, Dr. R. R. Mad- R.T.A. den, Dr. Norton Shaw. 1858. Leeds ...... Sir R. I. Murchison, G.C.S8t.S.,/R.Cull, Francis Galton, P.O’ Callaghan, FE.R.S. Dr. Norton Shaw, Thomas Wright. 1859. Aberdeen .,./Rear-Admiral Sir James Clerk|Richard Cull, Professor Geddes, Dr. . Ross, D.C.L., F.R.S. Norton Shaw. 1860. Oxford ...... Sir R. I. Murchison, D.C.L.,|\Capt. Burrows, Dr. J. Hunt, Dr. C. E.R.S. Lempriere, Dr. Norton Shaw. 1861. Manchester .|John Crawfurd, F.R.S............. Dr. J. Hunt, J. Kingsley, Dr. Norton Shaw, W. Spottiswoode. 1862. Cambridge ./Francis Galton, F.R.S. ............ J. W. Clarke, Rev. J. Glover, Dr. E Hunt, Dr. Norton Shaw, T. Wright. 1863. Newcastle...|Sir R. I. Murchison, K.C.B.,'C. Carter Blake, Hume Greenfield, E.R.S. C. R. Markham, R. 8. Watson. 1864. Bath......... Sir R. I. Murchison, K.C.B.,/H. W. Bates, C. R. Markham, Capt. F.R.S. R. M. Murchison, T. Wright. 1865. Birmingham|Major-General Sir H. Rawlinson,/H. W. Bates, S. Evans, G. Jabet, C. M.P., K.C.B., F.R.S. R. Markham, Thomas Wright. 1866. Nottingham |Sir Charles Nicholson, Bart.,,H. W. Bates, Rey. E. T. Cusins, R. ' LL.D. H. Major, Clements R. Markham, | D. W. Nash, T. Wright. 1867. Dundee...... Sir Samuel] Baker, F.R.G.S. .......H. W. Bates, Cyril Graham, C. R. Markham, 8. J. Mackie, R. Sturrock. 1868. Norwich ... Capt.G.H. Richards, R.N., F.R.S.|T. Baines, H. W. Bates, C. R. Mark- : ham, T. Wright, SECTION E (continwed).—GEOGRAPHY. 1869. Exeter ...... Sir Bartle Frere, K.C.B., LL.D.,,H. W. Bates, Clements R. Markham, F.R.GS. J. H. Thomas. 1870. Liverpool ...\Sir R. I. Murchison, Bt., K.C.B.,|H. W. Bates, David Buxton, Albert LL.D., D.C.L., F.R.S., F.G.8.| J. Mott, Clements R. Markham. 1871. Edinburgh. |Colonel Yule, C.B., F.R.G.S. ...|\Clements R. Markham, A. Buchan, | J. H. Thomas, A. Keith Johnston. 1872. Brighton .../Francis Galton, F.R.S. ............ H. W. Bates, A. Keith Johnston, Rev. J. Newton, J. H. Thomas. 18738. Bradford ...\Sir Rutherford Alcock, K.C.B....|H. W. Bates, A. Keith Johnston, Cle- ments R. Markham. 1874. Belfast ....... Major Wilson, R.E., F.R.S.,/E. G. Ravenstein, E. C. Rye, J. H. F.R.G.S. Thomas. 1875, Bristol ......|Lieut.-General Strachey, R.H.,{H. W. Bates, E. C. Rye, F. F. Tuckett. C.S.1., F.R.S., F.R.G.S., F.L.8., | E.GS. 1876. Glasgow ...\Capt. Evans, C.B., F.B.S.......... H. W. Bates, EH. C. Rye, R. Oliphant : : Wood, STATISTICAL SCIENCE. COMMITTEE OF SCIENCES, VI.—STATISLICS, 1833. Cambridge .|Prof. Babbage, F.R.S. ............\J. EH. Drinkwater. 1834, Edinburgh ./Sir Charles Lemon, Bart. ......... Dr. Cleland, C. Hope Maclean. ee = Date and Place. 1845. 1846. Southampton 1847. 1848. 1849. 1850. 1851. 1852. 1853. 1854. 1855. 1856. 1857. 1858. 1859. 1860. 1861. 1862. 1863. 1864. . Liverpool... . Newcastle... . Birmingham | . Glasgow .. . Plymouth... . Manchester . PRESIDENTS AND SECRETARIES OF THE SECTIONS. Dublin 5... | . Bristol Cambridge . Oxford Swansea Birmingham Edinburgh .. Ipswich...... Belfast Hull Liverpool ... Glasgow ..... .|.Rt. Hon. Lord Sandon, M.P., E.R.S. _ {Travers Twiss, D.C.L., F.R.S. ... ../J. H. Vivian, M.P., F.R.S. ...... Presidents. XX¥1X Secretaries. SECTION F.—STATISTICS. ‘Charles Babbage, F.R.S. ... Sir Charles Lemon, Bart., F. R. Ss. Rt. Hon. Lord Sandon Colonel Sykes, F.R.S. ....ssseeee Henry Hallam, F.RS. ............ Lieut.-Col. Sykes, F.R.S. | G. W. Wood, M.P., F.LS. Sir C. Lemon, Bart., M.P. ...... Lieut.-Col. Sykes, F.R.S., F.L.S. Rt. Hon. The Earl Fitzwilliam... G. RB, Porter, HRS. c.ccscseccsoes Rt. Hon. Lord Lyttelton Very Rev. Dr. John Lee, V.P.R.S.E. Sir John P. Boileau, Bart. His Grace the Archbishop of Dublin. James Heywood, M.P., F.R.S.... Thomas Tooke, F.R.S. ‘Dr. Finch, ....W. Greg, Prof. Longfield. Rev. J. E. Bromby, C. B. Fripp, James Heywood. W. R. Greg, W. Langton, Dr. W. C, Tayler. W. Cargill, J. Heywood, W. R. Wood. F. Clarke, R. W. Rawson, Dr. W. C. Tayler. iC. R. Baird, Prof. Ramsay, R. W. Rawson. ..|Rev. Dr. Byrth, Rey. R. Luney, R W. Rawson. Rey. R. Luney, G. W. Ormerod, Dr. W. C. Tayler. Dr. D. Bullen, Dr. W. Cooke Tayler. J. Fletcher, J. "Heywood, Dr. Laycock. J. Fletcher, W. Cooke Tayler, LL.D. J. Fletcher, F. G. P. Neison, Dr. W. C. Tayler, Rey. T. L. Shapcott. Rey. W. H. Cox, J. J. Danson, F. G. P. Neison. J. Fletcher, Capt. R. Shortrede. Prof. Hancock, F. G. P. Neison. Prof. Hancock, J. Fletcher, Dr. J. Stark. J. Fletcher, Prof. Hancock. Prof. Hancock, Prof. Ingram, James MacAdam, Jun. Edward Cheshire, William Newmarch. 'E. Cheshire, J. T. Danson, Dr. W. H. R. Monckton Milnes, M.P. ...... Duncan, W. Newmarch. ‘J. A. Campbell, HE. Cheshire, W. New- | march, Prof. R. H. Walsh. SECTION F (continwed).—ECONOMIC SCIENCE AND STATISTICS, Cheltenham tenes Manchester Cambridge. . Newcastle ... Bath os sise ves (Rt. Hon. Lord Stanley, M.P. .. ‘Edward Baines ...Col. Sykes, M.P., F.R.S. ......... His Grace the Archbishop of, Dublin, M.B.1.A. Peete e eet ene nen enees Nassau W. Senior, M.A. William Newmarch, F.R.S. ...... Edwin Chadwick, C.B. ............ William Tite, M.P., F.R.S. .... Willen Farr, M.D., D.C.L., F.RB.S. 1865. Birmingham Rt, Hon. Lord Stanley, LL.D., iP | .|Rey. C. H. Bromby,E. Cheshire, Dr. W. N. Hancock, W. Newmarch, W. M. Tartt. Prof. Cairns, Dr. H. D. Hutton, w. Newmarch. iT. B. Baines, Prof. Cairns, 8. Brown, Capt. Fishbourne, Dr. Fil Strang. Prof. Cairns, Edmund Macrory, A. M. Smith, Dr. John Strang. Edmund Macrory, W. * Newmarch, Rev. Prof. J. EB. T. Rogers. David Chadwick, Prof. R. C. Christie, EH. Macrory, Rey. Prof. J. E. T. Rogers. H.D. Macleod, Edmund Macrory. paltes Doubleday, Edmund Macrory, Frederick Purdy, James Potts. E. Macrory, E. T. Payne, F. Purdy. G. J. D. Goodman, G. J. Johnston, E. Macrory. xl REPORT—1876. | Date and Place. Presidents. Sceretaries. 1866. Nottingham |Prof. J. E. T. Rogers............... R. Birkin, Jun., Prof. Leone Levi, E. Macrory. 1867. Dundee...... M. i, Grant wie SMe.” coves. s0: Prof. Leone Levi, E. Macrory, A. J. | Warden. 1868. Norwich ....SSamuel Brown, Pres. Instit. Ac-/Rev. W. C. Davie, Prof. Leone Levi. | tuaries. 1869. Exeter ...... (Rt. Hon. Sir Stafford H. North-/Edmund Macrory, Frederick Purdy, | cote, Bart., C.B., M.P. Charles T. D. Acland. 1870. Liverpool...|Prof. W. Stanley Jevons, M.A. ..|Chas. R. Dudley Baxter, E. Macrory, J. Miles Moss. 1871. Edinburgh |Rt. Hon. Lord Neaves............. J. G. Fitch, James Meikle. 1872. Brighton .../Prof. Henry Fawcett, M.P. .......J. G@. Fitch, Barclay Phillips. 1873. Bradford ....Rt. Hon. W. E. Forster, M. P.... J. G. Fitch, Swire Smith. 1874. Belfast ...... (ord! O Wagram. Videcsstcexs.csecene: Prof. Donnell, Frank P. Fellows, Hans MacMordie. 1875. Bristol ...... ‘James Heywood, M.A., F.R.S.,/F. P. Fellows, T. G. P. Hallett, E. Pres.8.8S. Macrory. 1876. Glasgow ...'Sir George Campbell, K.C.8.1.,/A. M‘Neel Caird, T. G. P. Hallett, M.P, Dr. W. Neilson Hancock, Dr. W. Jack. MECHANICAL SCIENCE. SECTION G,—MECHANICAL SCIENCE. 1836. Bristol ...... ‘Davies Gilbert, D.C.L., F.R.S..../T. G. Bunt, G. T. Clark, W. West. 1837. Liverpool ...|Rey. Dr. Robinson .................. Charles Vignoles, Thomas Webster. 1838. Newcastle . ‘Charles Babbage, F.R.S. .. .|R. Hawthorn, C. Vignoles, T. Webster. 1839. Birmingham Prof. Willis, FR. 8., and Robert|W. Carpmael, William Hawkes, Tho- Stephenson. mas Webster. 1840. Glasgow ...\Sir John Robinson...............42. J. Scott oe a J. Thomson, J. Tod, C. Vignoles. 1841. Plymouth... John Taylor, F.R.S. ............... Henry Chatfield, Thomas Webster. 1842. Manchester .'Rev. Prof. Willis, F.R.S. ........./J. F. Bateman, J. Scott Russell, J. Thomson, Charles Vignoles. 1848. Cork ......... Prof. J. Macneill, M.R.1.A.......;James Thomson, Robert Mallet. 1844. York ......... John Vaylor vB RSs asc. .cercsee ose Charles Vignoles, Thomas Webster. 1845. Cambridge ..|George Rennie, F.R.S. ....|Rev. W. T. Kingsley. 1846, Southampton|Rey. Prof. W illis, M. re “FR. 8. .|William Betts, jun., Charles Manby. 1847. Oxford ...... Rey. Prof. Walker, M. J , B.R.S.|J. Glynn, R. A Le Mesurier. 1848. Swansea .....|Rev. Prof. Walker, M.A., F.R.S./R. A. Le Mesurier, W. P. Struvé. 1849. Birmingham )Robert Stephenson, M.P., F.R.S.|Charles Manby, Ww. P. Marshall. 1850. Edinburgh ..|Rev. Dr. Robinson. ............... Dr. Lees, David Stephenson. 1851. Ipswich...... William Cubitt, F-R.S............. John Head, Charles Manby. 1852. Belfast ...... John Walker,C.E., LL.D., F.R.S.|\John F. Bateman, C. B. Hancock, Charles Manby, James Thomson. 1853. Hull ...... .»..|William Fairbairn, C.E., F.R.S. ;famesOldsam, J.Thomson, W. Sykes War 1854, Liverpool .../John Scott Russell, F.R.S. ....../John pacliee J. Oldham, J. Thom- son. 1855. Glasgow ...|W. J. Macquorn Rankine, C.E.,'L. Hill, Jun., William Ramsay, J, : E.R.S. Thomson. 1856. Cheltenham |George Rennie, F.R.S. ............ \C. Atherton, B. Jones, jun, H. M. Jeffery. 1857. Dublin ...... The Right Hon. The Earl of|Prof. Downing, W.'T. Doyne, A. Tate, Rosse, F.R.S. James Thomson, Henry Wright. 1858. Leeds......... William Fairbairn, F.R.S. ......\J. C. Dennis, J. Dixon, H. Wright. 1859. Aberdeen ,,.)Rev. Prof. Willis, M.A., F.R.S. .|R. Abernethy, P. Le Neve Foster, H. Wright. 1860. Oxford ...... Prof. W. J. es Rankine, 'P. Le Neve Foster, Rey. F. Harrison , LL.D., F.R | Henry Wright. —_——— 2 Date and Place. ) 1861. Manchester . 1862. Cambridge .. 1863. Newcastle... 1864. Bath 1865. Birmingham 1866. Nottingham 1867. Dundee 1868. Norwich 1859. Exeter 1871. Edinburgh 1872. Brighton 1874. Belfast...... 1875. Bristol 1876. Glasgow Date and Place. | 1842. Manchester . nen eeenee 1844. York teneeeees 1845. Cambridge .. 1846.Southampton 1846. Southampton 1847, Oxford ..|@. P. Bidder, C.E., F.R.G.S. ... 1870. Liverpool... .../E. J. Bramwell, C.H.........0000 1873. Bradford ... ...|C. W. Merrifield, F.R.S. ......... LIST OF EVENING LE CTURES. xli Presidents. J. F. Bateman, C.E., F.B.S....... William Fairbairn, LL.D., F.B.S., Rev. Prof. Willis, M.A., F.R.S. .! J. Hawkshaw, F\R.S. ...........- | Sir W. G. Armstrong, LL.D., F.R.S. Thomas Hawksley, V.P.Inst. C.F, F.G.S. Prof. W. J. Macquorn Rankine,| LL.D., F.RB.S. C. W. Siemens, F.R.S. ............ Chas. B. Vignoles, C.H., F.R.S. . Prof. Fleeming Jenkin, F.R.S....| W. H. Barlow, F.R.S. ... wee ea eeee Prof. James Thomson, LL.D.,| C.E., F.R.S.E. W. Froude, C.E., M.A., F.R.S.... Secretaries. P. Le Neve Foster, John Robinson, H. Wright. W. M. Fawcett, P. Le Neve Foster. P. Le Neve Foster, P. Westmacott, J. F. Spencer. P. Le Neve Foster, Robert Pitt. P. Le Neve Foster, Henry Lea, W. P. Marshall, Walter May. P. Le Neve Foster, J. F. Iselin, M. A. Tarbottom. P. Le Neve Foster, John P. Smith, ‘W. W. Urquhart. P. Le Neve Foster, J. F. Iselin, C. Manby, W. Smith. P. Le Neve Foster, H. Bauerman. H. Bauerman, P. Le Neve Foster, T. King, J. N. Shoolbred. H. Bauerman, Alexander Leslie, J. P, Smith. ...\H. M. Brunel, P. Le Neve Foster, J. G. Gamble, J. N. Shoolbred. Crawford Barlow, H. Bauerman, E. H. Carbutt, J. C. Hawkshaw, J. N. Shoolbred. A. T. Atchison, J. N. Shoolbred, John Smyth, jun. W. R. Browne, H. M. Brunel, J. G. Gamble, J. N. Shoolbred. W. Bottomley, jun., W. J. Millar, J. N. Shoolbred, J. P. Smith. List of Evening Lectures. | Lecturer. | Subject of Discourse. "Charles Vignoles, F.R.S........4. | (Stevie iesranell 0 asyen canis «. R. I. Murchison. ...........:....2- Prof. Owen, M.D., F.R.S. ...... Prof. E. Forbes, F.R.S. ......... Drs Robinson eo.) .5. sisiscsteeont Charles Lyell, F.R.S. ............ Dr. Falconer, F.R.S8. G. B. Airy, F.R.S., Astron. Royal R. I. Murchison, F.R.S8......... Prof. Owen, M.D., F.R.S. ......' Charles Lyell, F.R.S. ............ W. R. Grove, F.R.S. ............ Rey. Prof. B. Powell, F.R.S. ... Prof. M. Faraday, F.R.S. wees Hugh E. Strickland, F.G.8. The Principles and Construction of Atmospheric Railways. The Thames Tunnel. The Geology of Russia. The Dinornis of New Zealand. The Distribution of Animal Life in the AXgean Sea. The Earl of Rosse’s Telescope. Geology of North America. The Gigantic Tortoise of the Siwalik Hills in India. Progress of Terrestrial Magnetism. Geology of Russia. Fossil Mammalia of the British Isles. Valley and Delta of the Mississippi. Properties of the Explosive substance discovered by Dr. Schonbein ; also some Researches of his own on the Decomposition of Water by Heat. Shooting-stars. Magnetic and Diamagnetic Pheno- mena. .| The Dodo (Didus ineptus). xhi REPORT—1876, Date and Place. 1848. Swansea 1849. Birmingham 1850. Edinburgh. 1853. 1854. 1855. 1856. . Aberdeen ... 1860. Oxford 1861 1862 1863 - Manchester . . Cambridge . . Newcastle- on-Tyne. 1863 1864 1865 . Neweastle- on-Tyne. . Bath . Birmingham 1866 .| John Percy, M.D., F.R.S. ...... . Nottingham! Lecturer. W. Carpenter, M.D., F.R.S. Dr. Faraday, ELS AE eds, be Rey. Prof. Willis, M.A., F.R.S. Prof. J. H. Bennett, M.D., E.R.S.H. DrMantell, BIBS. cc,0csccseo06. 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., FE.G.S. Robert Hunt, F.R.S. Prof. R. Owen, M.D., F.R.S.... Col. E. Sabine, V.P.R.S. ....:.... Dr, W. B. Carpenter, F.R.S. ... Lieut.-Col. H. Rawlinson Col. Sir H. Rawlinson WirthiiGroverwHekt Ss. cccsescesans 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.NS. ... Sir R.I. Murchison, D.C.L. ...... Rey. Dr. Robinson, F.R.S. ...... Rey. Prof. Walker, F.R.S. ......| Captain Sherard Osborn, R:N. .| Prof. W. A. Miller, M.A., F.R.S. G, B. Airy, F.R.8., Astron. Roy. . Prof. Tyndall, LL.D., F.RB.S. ... Prof. Odling, WARS. <....-s0.+.-00- Prof. Williamson, F.R.S. James Glaisher, F.R.S. Prof. Roscoe; BVR.S:.....00de+sss 0 Dr. Livingstone, F.R.S. ......... J. Beete Jukes, F.R.S. ............ William Huggins, F.R.S..........) Subject of Discourse. 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 Ani- mals, and their changes of Form. Total Solar Eclipse of July 28, 1851. Recent discoveries in the propreties of Light. Recent discovery of Rock-salt at Car- rickfergus, and geological and prac- tical considerations connected with it. Some peculiar phenomena in the Geo- logy 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 Cunei- form 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 rare- fied 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 Dy- namics. The Balloon Ascents made for the British Association. The Chemical Action of Light. Recent Travels in Africa. Probabilities as to the position and extent of the Coal-measures beneath the red rocks of the Midland Coun- ties. The results of Spectrum Analysis Dr, J. D: Hooker, F-R.S.........-| ‘Insular Floras. applied to Heayenly Bodies. Date and Place. 1867. 1868. 1869. . Bristol Dundee Norwich .... . Liverpool ... . Edinburgh 2. Brighton ... . Bradford ... . Belfast serene seeeee . Glasgow ... . Liverpool ... . Brighton ... . Bradford ... LIST OF EVENING LECTURES, Lecturer. xliii Subject of Discourse, Archibald Geikie, F.R.S.......... Alexander Herschel, F.R.A.S.... teeta eee ees Dr. W. Odling, F.R.S. ........... Prof. J. Phillips, LL.D., F.R.S. J. Norman Lockyer, F.R.S....... J. Fergusson, F.R.8. Prof. J. Tyndall, LL.D., F.R.S. Prof. W. J. Macquorn Rankine, LL.D., F.R.S. PAS Alba) TR ARAB. ace cit vss nero ei ES Os eID 9. scanssng es se Prof. P. Martin Duncan, M.D., F.R.S. Prof. W. K. Clifford .............. Prof. W. C. Williamson, F.R.S8. Prof. Clerk Maxwell, F.R.S.. Sir John Lubbock, Bart., MP., E.R.S. Prof. Huxley, F.R.8. 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 ef the Stars and Nebulz. The Scientific Use of the Imagination. Stream-lines and Waves, in connexion with Naval Architecture. Some recent investigations and appli- cations 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. William Spottiswoode, LL.D.,) The Colours of Polarized Light. E.RB.S. F. J. Bramwell, F.R.S. Perot. Patt, HAS, 2. .s..re ye sem | F .-| Prof. Huxley Railway Safety Appliances. orce Sir Wyville Thomson, F.R.S. .. -| The ‘ Challenger’ Expedition. Lectures to the Operative Classes. Prof. J. Tyndall, LL.D., F.R.S. , LL.D., F.BS. ... Prof. Miller, M.D., F.R.S. ...... 7 dau Lubbock, Bart., M.P., Willie Spottiswoode, LL.D., FE.BS. C. W. Siemens, D.C.L., F.R.S... Professor Odling, F.R.S.......... ... Commander Cameron, C.B.RB.N. Dr. W. B. Carpenter, F.RB.S. .. Matter and Force. A piece of Chalk. Experimental illustrations of the modes of detecting the Composi- tion of the Sun and other Heavenly Bodies by the se anes Savages. Sunshine, Sea, and Sky. Fuel. The Discovery of Oxygen. A piece of Limestone. A Journey through Africa. xliv | Date of Meeting. / 1831, Sept. 27 ... 1832, June Ig ... 1333, June 25 ... 1834, Sept.3 .. 1835, Aug. 10 ... 1836, Aug. 22 ... 1837, Sept. 11 ... 1838, Aug. 10 ... 1839, Aug. 26 .. 1840, Sept. 17 ... 1841, July 20 .. 1842, June 23 ... TOARS CATE, L7 loss | 1844, Sept. 26 ... | 1845, June Ig ... | 1846, Sept. 10 ... | 1847, June 23 ... | 1848, Aug. 9 1849, Sept. 12 | 1850, July 21 1851, July 2... 1852, Sept. 1 1853, sept. 3. 1854, Sept. zo ... 1855, Sept. 12 ... 1856, Aug. 6 1857, Aug, 26 ... 1858, Sept. 22 -.. | 1859, Sept. 14 ... 1860, June 27 ... 1861, Sept. 4 | 1862, Oct. x 1863, Aug. 26 ... 1864, Sept. 13 . 1865, Sept. 6 1866, Aug. 22 1867, Sept. 4 1868, Aug. 19 ...| Birmingham .| Plymouth ...| Birmingham ..| Edinburgh ...| [Ipswich ..| Belfast ...| Manchester ..| Bath ...| Birmingham ...| Nottingham .-.| Dundee ...| Norwich REPORT—1876, Where held. Oxford oo. sccesesees. See ene ee eeee Table showing the Attendance and Receipis Presidents. The Earl Fitzwilliam, DICE. The Rey. W. Buckland, F.R.S. .. | The Rey. A. Sedgwick, F.R.S.... ' Sir T. M. Brisbane, D.C.L. ...... The Rey. Provost Lloyd, LL.D. Liverpool Newcastle-on-Tyne.. Glasgow wees Manchester Cork MVOUK ws tees. seer sve cones Cambridge Southampton Oxford Swansea de [vt epee ey See eee Liverpool Glasgow .:.... Cheltenham Dublin 17-5 eee eae Pee Aberdeen ,........504! Oxtord © 2.600 Se ee Cambridge Newcastle-on-Tyne .. 1860, Aug. 18 ...| Eixeter.................- 1870, Sept. 14 ...| Liverpool ............ 1871, Aug. 2......, Edinburgh ......... 1872, Aug. 14 ...| Brighton ....,....... | 1873, Sept.17 ...| Bradford ............ |1874, Aug.19 ...| Belfast ............. [1875, Aug. 25 ...| Bristol ..,....0....... 1876, Sept. 6...... | GlasZow....ccrsssceseee 1$77,"Aug. 15 ...| Plymouth ............ | The Lord Francis Egerton The Marquis of Lansdowne |The Earl of Burlington, F.R.S.. The Duke of Northumberland... The Rey. W. Vernon Harcourt. The Marquis of Breadalbane ... The Rev. W. Whewell, F.R.S.... The Earl of Rosse, F.R.S. .... The Rey. G. Peacock, D.D....... Sir John F. W. Herschel, Bart. . Sir Roderick I. Murchison, Bart. Sir Robert H. Inglis, Bart. ...... The Marquis of Northampton... The Rey. T. R. Robinson, D.D.. Sir David Brewster, K.H. G. B. Airy, Esq., Astron. Royal . | Lieut.-General Sabine, F.R.S. ... William Hopkins, Esq., F.R.S. . The Earl of Harrowby, F.R.S. .. .| The Duke of Argyll, F-R.S. ...... Prof. C. G. B. Daubeny, M.D.... The Rev. Humphrey Lloyd, D.D. Richard Owen, M.D., D.C.L. . | H.R.H. The Prince Consort The Lord Wrottesley, M.A....... William Fairbairn, LL.D.,F.R.S. _The Rev. Prof. Willis, M.A. ... | Sir William G. Armstrong, C.B. Sir Charles Lyell, Bart., M.A.... | Prof. J. Phillips, M.A., LL.D.... | William R. Grove, Q.C., F.R.S. |The Duke of Bucclench, K.C.B. Dr. Joseph D. Hooker, F.R.S. . Prof. G. G. Stokes, D.C.L. ...... Prof. T. H. Huxley, LL.D....... | Prof. Sir W. Thomson, LL.D.... Dr. W. B. Carpenter, F.R.S. ... Prof. A. W. Williamson, F.R.S. Prof. J. Tyndall, LL.D., E.R. Sir John Hawkshaw, C. EK. sE.R.S Prof. T. Andrews, M.D., o R.S. Prof. A. Thomson, M.D., F.R.S Old Life Members. 393 226 313 241 314 235 172 194 182 236 222 286 321 237 292 204. 314 245 212 162 239 221 Members. New Life | Annual Associates. 33t gt 407 270 495 376 447 510 244 - 510 367 755 1094 412 goo 7190 1206 636 1589 433 1704, IIIg 766 g60 1163 720 678 1103 976 937 796 817 884. 1265 ATTENDANCE AND RECEIPTS AT ANNUAL MEETINGS, xlv Ladies. 1100* 60* gar" 160 260 172 196 203 197 237 273 141 292 236 524 543 346 569 BoD 821 463 791 242 1004, 1058 5c8 77% 771 682 600 gio 754 gI2 6o1 630 672 712 Foreigners. Total. 353 goo 1298 1350 1840 2400 1438 1353 891 1315 1079 857 1260 929 1071 1241 710 1108 876 1802 2133 1115 2022 1698 2564. 1689 3139 1161 3335 2802 1997 2303 2444. | 2004. 1856 2878 24.63 2533 1983 1951 2248 - 2774 * Ladies were not admitted by purchased Tickets until 1843. t Tickets for admission to Sections only, Amount received. during the Meeting. bee eeeene ten eeeeee sent eneee Sere eenes see eeenee eee eenee O*O"'O O00 07050 0 SC Olay Ol0 701 © O10 10 6-0 .6:0 0.0650 Cc0O0000 00000000000 A0A0O0OAAaa A000 0”0 Sums paid on! Account of Grants for Scientific Purposes. eee eeee eee Coe ery cI m4 Dds a fe) Cal ) -) WB An ro] nl NX o rs] -_ nn ro) m4 FPODO0IAROOF ¢ Including Ladies. PODDAONDAODAOBROMODOORRWOBNONNO DOP OW OP DOHRON DOO O L al plex 6 S PF 2601 © aoe 8 +96 G FOL 0 OLF &@ 802 ol FOP *s $ G 0 ooo oceoceoonoeocoseoosooosooscsesg "981 ‘9 taquiaydag ‘NOSINVITTIM ‘A ‘V eer rere rrr) 6 6 0 00g ~ JaInsvar], [e1aUey JO spuey UT YseD Hee eee me eee rete eeeeeee (qunoo0e8 41sodap) 0341p ‘oud 61 LO Fee ae Re Rainn ecieic ne sieiatinis sineie''e'esivisinins (qunoo0e qUaIINd) UR IaysuranysaA\ pue uopuory ye aouryeg 0 ¢ ~~ sdryg ureeyg Jo Suyumy, wo zayjodoarg Jo yoo OL Unveevasesseessares puLyjoog ui seyenbyjaegy GL &L * sa}IUIULOD oLyemModo1yUy Cl 6 toes seeecvecsouss “wer 8 myQ Suse, SVU snouespuy Jo uoyIe}0r1g aOy aT, as0TO “ spmbry jo soumyo, oytoody * wotyeto[dxy uLeAeyD 84ue yy “TOT BIOTUxG aaRy o[430g ‘ouTpRY SUyBMoeH epry, eusduspewvantnen Teyurey, ysrgntge ‘soTde NT 9B UORIG [BoIs0[007 ouoIspuBY PayT MENT UI S194BA\ Punoasdopuy—) ite ee et sdiqg jo peedg SuLMsve fT (sorquy, eoyRMeyQe yy Suyuid) suoyoung oydrysy ve : plodayy Teo1s0[007 SYOOY JO saytAyonpuoy [eursayy, ** S[O8aID OToUIOST * SUOTJAAOVg [BUT}SAqUT a 048j908-03 -aoepog [AYIA UO oyvrd4gngomorg [AyIy Jo UOYOY Pree cere errr p.loaary [eerdojoan ““pumog jo uoloy peodoyorséy T “ploy onoydsoyg pus ysejog Jo uoyeMyssy “9L8T — "214 ‘Buyaapy [OIslIg 91} 98 apeul szuBIH “ “+ (qaaa}g aplvaieq)y) sasuadxy voyO pue quey “ Peet een men eeeeetene (reak 1) sarieyes ‘ sree (qgurtag) a ‘TIITX 109A ‘Suyooq ysFF Jo yxodey ‘op ‘SuravsSugq ‘Suyuug “ srereeeeeereeeeeee sosuadxg [equapiouy pue ‘Sursyteapy ‘Sur -pulg ‘Sunuizg Aipung osje Suneayy [ojsiig Jo sosuedxg preg “SUNGNAVd L Gl €FLE 6 It 9L sy Lt) re lit ef ol Likes | LEZ oL9 88 899 61P F369 ¥ maeocescon ir) be) mooocoen aol o cy L BL erLer if ‘XGHOVULS “W ii | “AQOOMSILLOdS ‘WM ‘UGLSOd “0 “9 *709L100 pUNOF pue sayoNoA yy YILM poulMEXg stash neriGaa naninnicnieisen«naivannte oasitat Asie sn Gnade et arraey JoISUIMIYSAA, PUB UOpuOT 4e yIsodaq uo yseIezUT See eee ee nee eeeeene Buryadqy jowug Surmp siaquiayy 0} siadvq Jo uoisstmsuesy, «07 Rabseoson ae FB p nse enaae Be eu -oopaude reeseetetes goqarar “MoD TTyULKY ysyig 55's Sh Oey qse wody qysnoiq aour[eg OL “SLdIGO aa ‘SuysaY MOSsepH Jo yunod0v uo sydrevay Surpnour jon *( MODSVTYD) 9Z81 ‘9 raquiajgdag 0} (Suna TOLSTUA Jo yuoweousmmos) ¢zgy ‘cz ysnSny woy LNQOOOV SUAYNSVAUL TVYUANAS GAL “HONAIOS FO LNANAONVAGV FHL YOdA NOLLVIOOSSV HSILIYA AHL 4“ a “cc a OFFICERS OF SECTIONAL COMMITTEES. xlvii OFFICERS OF SECTIONAL COMMITTEES PRESENT AT THE GLASGOW MEETING. SECTION A.— MATHEMATICS AND PHYSICS. President.—Professor Sir William Thomson, M.A., LL.D., D.C.L., F.R.S., F.R.S.E. Vice-Presidents:—Professor Blackburn, M.A:; Professor Cremona; Professor Grant, M.A., LL.D., F.R.S., F.R.A.S.; Rey. Professor Haughton; M.A., F.R.S. ; Professor A. S. Herschel, B.A., F.R.A.S.; Dr. J. Janssen; Rev. Dr. Lloyd, F.R.S.; Professor Clerk Maxwell, F.R.S.; Professor G. G. Stokes, See.R.8. ; Professor P. G. Tait, F.R.S.E. ; Professor Willner. Secretaries.—Professor W. F. Barrett, F.R.S.E., M.R.LA., F.C.S.; J. T. Bottom- ley, M.A., F.R.S:E., F.C.S.; Professor G. Forbes, B:A., F.R.S.E.; J. W. L. Glaisher, M.A., F.R.S., F.R.A.S. ; Thomas Muir, M.A., F.R.S.E. SECTION B.—CHEMISTRY AND MINERALOGY, INCLUDING THEIR APPLICATIONS TO AGRICULTURE AND THE ARTS. President.—W. H. Perkin, F.R.S., Secretary of the Chemical Society. Vice-Presidents.—Professor T. Andrews, M.D., F.R.S.; Professor Crum Brown, M.D., F.R.S.E.; W. Crookes, F.R.S.; Professor J. Ferguson, M.A. ; Professor G. C. Foster, F.R.S.; Dr. Gilbert, F.R.S.; Professor J. H. Gladstone, F.R.S. ; Professor Edmund J. Mills, D.Sc., F.R.S.; Professor A. W. Williamson, F.B.S. ; James Young, F.R.S. Secretaries.—W. Dittmar; W. Chandler Roberts, F.R.S.; John M. Thomson, F.C.S.; W. A. Tilden, D.Sc. SECTION C.—GEOLOGY. President.—Professor John Young, M.D. Vice-Presidents—His Grace the Duke of Argyll, K.T., LL.D., F.R.S. ; Professor A. Geikie, LL.D., F.R.S.; Professor E. Hull, F.R.S.; J. Gwyn Jeffreys, LL.D., F.R.S.; W. Pengelly, F.R.S.; Rev. T. Wiltshire, M.A., F.G.S. Secretaries.—Jas. Armstrong; F. W. Rudler, F.G.S.; W. Topley, F.G.S. SECTION D.—BIOLOGY. President.—A. Russel Wallace, F.L.S., F.R.G.S. Vice-Presidents.—Professor Balfour, M.D., F.R.S8.; G. Bentham, F.R.S,; Professor A. Buchanan, M.D.; Professor Cleland, M.D., F.R.S.; Dr. Ferdinand Cohn; ' Professor Dickson, M.D., F.L.S.; Professor Grube; Professor Haeckel; Dr. Hooker, P.R.S.; Dr. M‘Kendrick, I’.R.S.E.; Professor Morren; Professor Newton, F.R.S.; Dr. Redfern ; Dr. Allen Thomson, F.R.S. ; Sir Wyville Thom- son, F.R.S. ; Rev. Canon Tristram, F.R.S.; Professor W. C. Williamson, F.R.S. Secretaries.—K. R. Alston, F.Z.S.; Hyde Clarke; Dr. Knox, M.A ; Professor W. R. M‘Nab, M.D.; Dr. Muirhead; Professor Morrison Watson, SECTION E.—GEOGRAPHY AND ETHNOLOGY. President.—Captain Evans, C.B., F.R.S., Hydrographer to the Admiralty. Vice-Presidents—General Sir James E. Alexander, K.C.B., F.R.G.S.; Sir T. E. Colebrooke, Bart., M.P.; Captain Douglas Galton, C.B., F.R.S.; A. Kinnaird, M.P.; Chevalier Cristoforo Negri; Col. R. L. Playfair; Commander E, H. Verney, R.N. Secretaries.—H. W. Bates, F.L.S., Assist. Sec. R.G.S.; E. C. Rye, F.Z.S., Librarian R.G.8.; R. Oliphant Wood. , SECTION F.—ECONOMIC SCIENCE AND STATISTICS, President.—Sir George Campbell, K.C.8.I., D.C.L., M.P., F.R.G.S. Vice-Presidents—G. Anderson, M.P.; Principal Caird, D.D.; Charles Cameron, LL.D., M.P.; J. G. Fitch, M.A.; J. Grieve, M-P.; G. W. Hastings; J. Hey- wood, F.R.S.; Judge Longfield; Lord O'Hagan ; The Lord Provost of Glasgow ; Sir James Watson. Secretaries.—A. M‘Neel Caird; T. G. P.. Hallett, M.A.; W. Neilson Hancock, LL.D., M.R.L.A.; W. Jack, M.A., LL.D. SECTION G.—MECHANICAL SCIENCE. President.—C. W. Merrifield, F.R.8, Vice- Presidents —C. Bergeron; F. J. Bramwell, F.R.S.; W. Froude, M.A., C.L., F.R.S.; Sir John Hawkshaw, F.R.S.; C. W. Siemens, D.C.L., F.R.S.; Thomas Stevenson; Professor James Thomson, M.A., LL.D., F.R.S.E. Secretaries W. Bottomley, jun.; W. J. Millar; J. N. Shoolbred, C.E., F.G.S. ; J.P. Smith, C.E. OFFICERS AND COUNCIL, 1876-77. PRESIDENT. PROFESSOR THOMAS ANDREWS, M.D., LL.D., F.B.S., Hon. F.R.S.E. VICE-PRESIDENTS. His Grace the Dore oF ARGYLL, K.T., LL.D., | Pagtesser Sir Witt1AM TuHomson, M.A., LL.D., E.R.S.L. & E., 8. F.R.S.L. & E. The LorpD edavbees or GLASGOW. | Professor ALLEN THomson, M.D., LL.D., F.R.8.L. Sir WiLLIAM STIRLING MAXWELL, & E. M.A,, M.P. | ”| Professor A. C. Ramsay, LL.D., F.R.S., F.G.S. | JAMES YOuNG, Esq., F.R.S., F.C.8, PRESIDENT ELECT. PROFESSOR ALLEN THOMSON, M.D., LL.D., F.R.S.L, & E. VICE-PRESIDENTS ELECT. The Right Hon. the Eart or MountT-EDGCUMBE. | WinLIAM FrRouDE, Esq., M.A., C.E., F.R.S. The Right Hon. Lorp BLACHForD, K.C.M.G. CHARLES SPENCE BATE, Esq., BR. 8, ELS. Witti1am Sporriswoopk, Esq., M.A., LL.D., | E.R.S., F.R.A.S,, F.R.G.S. LOCAL SECRETARIES FOR THE MEETING AT PLYMOUTH. WILLIAM ADAMS, Esq. HAMILTON WuITEFORD, Esq. WILLIAM SQuaARE, Esq. | LOCAL TREASURER FOR THE MEETING AT PLYMOUTH. Francis Hicks, Esq. ORDINARY MEMBERS OF THE COUNCIL. ABEL, F. A., Esq., F.R.S. JEFFREYS, J. Gwyn, Esq., a i ee AxLcock, Sir Rururerrorp, K.C.B. | MASKELYNF, Prof. N. S., F.R.S. BRAMWELL, F. J., Esq., C.E., F.R.S. | MAXWELL, Professor J. Cum, B RS, CAYLEY, Professor, F.R.S. MERRIFIELD, C. W., Esq., F.R.S. Der La Run, WARREN, Eaq., D.C.L., F.R.S. Newton, Professor ee ¥. R. 8. Evans, J., Usq., F.R.S. H OMMANNEY, Admiral B., C.B., E.R.8. Farr, Dr. W., F.R.S. PENGELLY, W., Esa., F. "B.S. FLOWER, Professor W. H., F.R.S. | PRESTWICH, Professor J., F.R.S. Frovupr, W., Esq., F.R.S. | RoLueEstToN, Professor G., M.A., F.R.8. Gasstor, J. P., Esq., D.C.L., LL.D., F.R.S Roscok, Professor H. E., Ph.D. F-R.S. Hrywoop, J., Esq., F.R.S | RUSSELL, Dr. W. J., F.R.S. HouGurTon, Rt. Hon. Lord, F.R.S. | SMITH, Professor H. J. 8., F.R.8. Hueains, W., Esq., ERS. | GENERAL SECRETARIES. Capt. DoUGLAS GALTON, C.B., D.C.L., F.R.S., F.G.S., 12 Chester Street, Grosyenor Place, London, 8.W. Puitie LUTLEY SCLATER, Esq., M. Ae Ph. D., E.R. 8, P.L.8., 11 Hanover Square, London, W. ASSISTANT GENERAL SECRETARY. GEORGE GRIFFITH, Esq., M.A., F.C.8., Harrow-on-the-hill, Middlesex, GENERAL TREASURER. Professor A. W. WILLIAMSON, Ph.D., F.R.8., 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 General Treasurers for the present and former years, and the Local Treasurer and Secretaries for the - ensuing Meeting. TRUSTEES (PERMANENT). General Sir EpwAnrD SABIne, K.C.B.. R.A., D.C.L., F.R.S, Sir PuILip DE M. GREY DPGERTON, Bart., M. P., F.R.8., F.G.S. Sir Joiux Luspock, Bart., M.P., F.R.S., BLS. PRESIDENTS OF FORMER YEARS. The Duke of Devonshire. | Richard Owen, M.D., D.C.L. | Prof. Huxley, LL.D., Sec. B.S. The Rey. T. R. Robinson, D.D. | Sir W. G. Armstrong, C.B., LL.D, | Prof. Sir W. ‘Thomson, D.C.L. sir G. B, Airy, Astronomer Royal. | Sir William R. Grove, I’. RS. | Dr, Carpenter, I'.R.S. General Sir E. Sabine, K.C.B. The Duke of Buccleuch, K.G. Prof. Williamson, Ph.D., F.R.S. The Harl of Harrowby. Dr. Joseph D. Hooker, D.C.L, Prof. Tyndall, D.C.L., F.R.S8. The Duke of Argyll. Professor Stokes, M.A., D.C.L. Sir John Hawkshaw, 0. E., F.R.8 The Rey. H. Lloyd, D.D. GENERAL OFFICERS OF TORMER YDARS. F. Galton, Esq., F.R.S. Gen. Sir E. Sabine, K.C.B., F.R.S. | Dr. T. Thomson, F.R.8. Dr. T. A, Hirst, F.R.S. W. Spottiswoode, Esq., F.R.8. Dr. Michael Foster, F.R.8. AWUDITORS. Professor G. C, Foster, I'.R,8. W. Spottiswoode, Esq., F.R.S. Major-General Strachey, F.R.S. REPORT OF THE COUNCIL. xlix Report of the Council for the Year 1875-76, presented to the General Commuttee at Glasgow on Wednesday, September 6th, 1876. The Council have much regret in announcing that Sir Robert Christison, who was elected President for the Glasgow Meeting, informed the Council in the course of last winter that he felt himself unable to preside, in conse- quence of the state of his health. Under these circumstances the Council selected Dr. Andrews, of Belfast, for nomination for the office of President ; and the first business of the General Committee of the Association will be to confirm this nomination, The Council also recommend that Mr. J. Young, F.R.S., be elected a Vice-President of the Association. The Council have received Reports during the past year from the General Treasurer, and his Accounts for the year will be laid before the General Com- mittee this day. The General Committee at Bristol referred the following four Resolutions to the Council for their consideration, and they beg to report their action thereon in each case :— First Resolution.—“ That the Council be requested to consider the re- commendations of the Reports of the Royal Commission on Scientific Instruction and the Advancement of Science, and to take such action thereupon as may seem to them best calculated to advance the inte- rests of Natural Science.” The Council having considered this Resolution, waited as a deputation upon the Lord President of the Council and upon the Secretary of State for the Home Department, and urged upon the Government the opinion of the Association that it is of the highest importance to the welfare of this country that the Government should without delay give systematic material aid to the development of the higher Scientific Education, in the spirit of the Fifth and Kighth Reports of the Royal Commission on Scientific Instruction and the Advancement of Science; and the Council further urged upon the Govern- ‘ment that, in the selection of Members of the proposed University Commis- sion, Science should be duly represented. The Government promised to give due consideration to the representations of the British Association ; and they have increased the amount of the Grant to the Royal Society for aiding Scientific Investigation. Second Resolution.—* That the Council be requested to take such steps as they think suitable for renewing their representations to the Secretary of State for India, as to the importance of establishing an Observatory for Solar Physics in India, in conformity with the recom- mendations of the Royal Commissioners on Scientific Instruction and the Advancement of Science.” The Council haying learned that steps were being taken in India in refer- ence to this matter, deemed it advisable to defer any action for the present. 1876. : d dike ~~ REPoRT—1876. : Third Resolution.“ That the Council be requested to consider and report upon the manner in which the Members of Committees and other Officers of the Association shall be selected, and whether Ladies shall be admitted to such offices, and if so, to what offices, and under what conditions.” : Upon this Resolution the Council have come to the following conclusion, Vi1Zz. :— That it does not appear to have been the practice of the British Association to elect Ladies as Officers of the Association, or to place them upon the General.or Sectional Committees ; and they are of opinion that no-case has been made out for altering the practice hitherto in force. Fourth Resolution —*“ That the Council be requested to take into con- sideration the expediency of appointing Representatives to attend the International Statistical Congress to be held at Buda-Pesth in 1876.” The Council have not taken any action on this Resolution. ‘ __ The Council regret to have to announce that Dr. Michael Foster, M.A., F.R.S., is unable to continue to act as one of the General Secretaries of the Association. They cannot refrain from expressing their regret at the loss of his valuable services. ; The Council have agreed to recommend that Mr. Philip Lutley Sclater, F.R.8., be appointed one of the General Secretaries in his place. Mr. Sclater’s name will be proposed to the General Committee at the Meeting for the Election of the Council and Officers on Monday next. __ The Council have added to the List of the Corresponding Members of the Association the names of the following gentlemen present at the last Meeting of the Association, viz. :— Dr. Nachtigal. Dr. Oppenheim. Dr. E. L. Youmans. The Council have been informed that invitations for the Meeting to be held in 1878, or following years, will be presented from Leeds and Dublin. The following are the names of Members of Council for the past year who, in accordance with the regulations, are not eligible for re-election this year, viz. :— Mr. Bateman. Right Hon. Lyon Playfair. Professor G. C. Foster. Dr. C. W. Siemens. Mr. Lockyer. The Council recommend the re-election of the other ordinary Members of Council, with the addition of the gentlemen whose names are distinguished by an asterisk in the following list ;— Abel, F. A., Esq., F.R.8. — - | *Froude, W., Esq., F.B.S. *Alcock, Sir Rutherford, K.C.B. Gassiot, J. P., Esq., D.C.L., LL.D., Bramwell, F. J., Esq., C.E., F.R.8. | F.R.S. *Cayley, Professor, F.R.S. Heywood, J., Esq., F.R.S. De La Rue, Warren, Esq., D.C.L., *Houghton, Lord, F.R.S. F.RS. | *Huggins, W., Esq., F.R.S. Evans, J., Esq., F.B.S. Jeffreys, J. Gwyn, Esq., F.R.S. Farr, Dr. W., F.RiS. Maskelyne, Prof. N. S., M.A., F.R.S, Flower, Professor W. H., F.R.S. | Maxwell Professor J. Clerk, F.R.S: Merrifield, C. W., Esq., F.R.S. Rolleston, Professor G., M.A., F.R.S. Newton, Professor A., F.R.S. Roscoe, Professor H. E., Ph.D., Ommanney, Admiral E., C.B., F.R.8.| F.R.S. _ Pengelly, W., Esq., F.R.S. / Russell, Dr. W. J., F.R.S. Prestwich, Professor J., F.R.S. ' Smith, Professor H. J. §., F.RB.S. _ RECOMMENDATIONS ADOPTED BY THE GENERAL CoMMITTEE AT THE GLASGOW ' Merrine in SEPTEMBER 1876. [When Committees are appointed, the Member first named is regarded as the Secretary, - a RECOMMENDATIONS OF THE GENERAL COMMITTEE. li except there is a specific nomination. ] : : Involving Grants of Money. That the Committee on Underground Temperature, consisting of Professor Everett, Professor Sir W. Thomson, Professor J. Clerk Maxwell, Mr. G. J. Symons, Professor Ramsay, Professor Geikie, Mr. J. Glaisher, Mr. Pengelly, Professor Edward Hull, Professor Ansted, Dr. Clement Le Neve Foster, Professor A. S. Herschel, Mr. G, A. Lebour, Mr. A. B. Wynne, Mr. Galloway, and Mr. Joseph Dickinson, be reappointed; that Professor Everett be the Secretary, and that the sum of £50 be placed at their disposal. That the Committee, consisting of Professor Stokes, Dr. De La Rue, Pro- fessor Clerk Maxwell, Professor W. F. Barrett, Mr. Howard Grubb, Mr. G. Johnstone Stoney, and Professor R. 8. Ball, for examining and reporting upon the reflective powers of silver, gold, and platinum, whether in mass or chemically deposited on glass, and of speculum metal, be reappointed ; _ and that the grant of £20 which has lapsed be renewed. That Professor Sir William Thomson, Professor Tait, Professor Grant, Dr. Siemens, and Professor Purser be appointed a Committee to undertake experiments for the Measurement of the Lunar Disturbance of Gravity ; and that the sum of £50 be placed at their disposal for the purpose. That the Committee on Thermo-Electricity, consisting of Professor Tait, Professor Tyndall, and Professor Balfour Stewart, be reappointed; and that the grant of £50 which has lapsed be renewed. _ That the Committee, consisting of Professor Cayley, Professor G. G. Stokes, Professor H. J. S. Smith, Professor Sir W. Thomson, and Mr. J. W. L. Glaisher (Secretary), be reappointed; that the tables of the Elliptic Functions be completed and published ; that the sum of £250 be placed at the disposal of the Committee for the purpose; and that it be referred to the Council to settle the details of publication. _ That the Committee, consisting of Dr. Joule, Professor Sir W. Thomson, Professor Tait, Professor Balfour Stewart, and Professor J. Clerk Maxwell, for effecting the determination of the Mechanical Equivalent of Heat, be eappointed ; and that the sum of £100 be placed at their disposal for the purpose. That the Committee on Luminous Meteors, consisting of Mr. James Glaisher, r. R. P. Greg, Mr. Charles Brooke, Dr. Flight, Professor G. Forbes, and Professor A. S. Herschel, be reappointed; that Professor Herschel be tho Sceretary, and that the sum of £30 be placed at their disposal. ¢ -~ lu REPORT—1876. That Professor G. Forbes and Professor Sir W. Thomson be a Committee for the purpose of endeavouring to make arrangements for the taking of certain observations of Atmospheric Electricity in India; that Professor G. Forbes be the Secretary, and that the sum of £15 be placed at their disposal for the purpose. ‘ That the Committee for investigating the methods employed in the esti- mation of Potash and Phosphoric Acid in commercial products be reappointed ; also that Mr. E. W. Parnell and Mr. Ogilvie be added to the Committee ; that Mr. Allen be the Secretary, and that the sum of £20 be placed at their disposal for the purpose. That Dr. William Wallace, Professor Dittmar, and Mr. Thomas Wills be a Committee for the purpose of reporting on the best means for the develop- ment of Light from Coal-gas of different qualities ; that Dr. Wallace be the Secretary, and that the sum of £20 be placed at their disposal for the purpose. That the Committee, consisting of Dr. F. Clowes and Dr. W. A. Tilden, for the purpose of examining the Action of Ethylbromo-butyrate on Ethyl Sod-aceto-acetate, be reappointed ; that Dr. Clowes be the Secretary, and that the sum of £10 be placed at their disposal for the purpose. That the Committee, consisting of Dr. Armstrong, Professor Thorpe, and Mr. W. W. Fisher, for the purpose of investigating the Isomeric Cresols and the Law of Substitution in the Phenol Series, be reappointed; that Dr. Armstrong be the Secretary, and that the sum of £10 be placed at their dis- posal for the purpose. That Mr. W. N. Hartley, Mr. J. M. Thomson, and Mr. W. Chandler Roberts be a Committee for the purpose of investigating the Constitution of Double Compounds of Cobalt and Nickel; that Mr. J. M. Thomson be the Secretary, and that the sum of £10 be placed at their disposal for the purpose. That Dr. Crum-Brown, and Messrs. Dewar, Dittmar, and Dixon be a Com- mittee for the purpose of investigating some methods that have been recently proposed for the Quantitative Estimation of Atmospheric Ozone; that Mr. EK. M. Dixon be the Secretary, and that the sum of £15 be placed at their disposal for the purpose. That Mr. W. N. Hartley, Dr. E. J. Mills, and Mr. W. Chandler Roberts be a Committee for the purpose of investigating the conditions under which liquid Carbonic Acid occurs in Minerals; that Mr. W. N. Hartley be the Secretary, and that the sum of £20 be placed at their disposal for the purpose. That Mr. J. Evans, Sir J. Lubbock, Bart., Mr. E. Vivian, Mr. W. Pen- gelly, Mr. G. Busk, Professor W. Boyd Dawkins, Mr. W. Ayshford Sandford, and Mr. J. E. Lee be a Committee for the purpose of continuing the ex- ploration of Kent’s Cavern, Torquay ; that Mr. Pengelly be the Secretary, and that the sum of £100 be placed at their disposal for the purpose. That Sir John Lubbock, Bart., Professor Prestwich, Professor Busk, Pro- fessor Hughes, Professor W. Boyd Dawkins, Rev. H. W. Crosskey, Messrs. L. C. Miall and R. H. Tiddeman be reappointed a Committee for the pur- pose of assisting in the exploration of the Victoria Cave ; that Mr. Tiddeman be the Secretary, and that the sum of £100 be placed at their disposal for the purpose. That Mr. J. Evans, Rev. T. G. Bonney, Professors A. H. Green and H. A. Nicholson, Messsrs. W. Carruthers, F. Drew, R. Etheridge, Jun., G. A. Lebour, L. C. Miall, F. W. Rudler, E. B. Tawney, W. Topley, and W. Whitaker be a Committee for the purpose of carrying on the Geological RECOMMENDATIONS OF THE GENERAL COMMITTEE. ln Record; that Mr. Whitaker be the Secretary, and that the sum of £100 be placed at their disposal for the purpose. That Professor Hull, Mr. E. W. Binney, Mr. H. Howell, Mr. M. Reade, Rey. H. W. Crosskey, Professor A. H. Green, Professor Harkness, Mr. W. Molyneux, Mr. G. H. Morton, Mr. Pengelly, Professor Prestwich, Mr. J. Plant, Mr. W. Whitaker, Captain D. Galton, and Mr. De Rance be a a Committee for the purpose of investigating) the circulation of the under- ground waters in the New Red Sandstone and Permian formations of England, and the quantity and character of the water supplied to various towns and districts from those formations ; that Mr. C. E. De Rance be the Secretary, and that the sum of £10 be placed at their disposal for the pur- pose. That Professor A. S. Herschel and Mr. G. A. Lebour be a Committee for the purpose of making experiments on the Thermal Conductivities of certain rocks ; that Professor Herschel be the Secretary, and that the sum of £10 be placed at their disposal for the purpose. That Dr. Bryce, Mr. J. Brough, Mr. G. Forbes, Mr. D. Milne-Home, Mr, J. Thomson, Professor Sir W. Thomson, and Mr. Peter Drummond be a Committee for the purpose of continuing the Observations and Records of Earthquakes in Scotland ; that Dr. Bryce be the Secretary, and that the sum of £10 be placed at their disposal for the purpose. That Mr. W. Topley, Mr. H. Willett, Mr. R. A. C. Godwin-Austen, Mr. Davidson, Prof. Prestwich, Prof. W. Boyd Dawkins, Mr. H. Woodward, and Prof. Hull be a Committee for the purpose of promoting the Sub-Wealden Exploration ; that Mr. Willett and Mr. Topley be the Secretaries, and that the sum of £100 be placed at their disposal for the purpose. That Professor Arthur Gamgee, Professor Roscoe, and Mr. Priestley be a Committee for the purpose of investigating the Physiological Action of Ortho-, Pyro-, and Metaphosphoric Acids and of allied compounds; that Professor Gamgee be the Secretary, and that the sum of £15 be placed at their disposal for the purpose. That Dr. Hooker, Professor Oliver, and Mr. Dyer be a Committee for the purpose of preparing a Report on the Family of the Dipterocarpex ; that Mr. Dyer be the Secretary, and that the sum of £20 be placed at their disposal for the purpose. That Mr. Stainton, Sir John Lubbock, and Mr. Sclater be a Committee for the purpose of continuing a Record of Zoological Literature; that Mr. Stainton be the Secretary, and that the sum of £100 be placed at their dis- posal for the purpose. That Professor Huxley, Dr. Carpenter, Mr. Sclater, Mr. F. M. Balfour, Dr. M. Foster, Professor Ray Lankester, and Mr. Dew-Smith be reappointed a Committee for the purpose of arranging with Dr. Dohrn for the occupation of a Table at the Zoological Station at Naples during the ensuing year ; that Mr. Dew-Smith be the Secretary, and that the sum of £75 be placed at their disposal for the purpose. That Colonel Lane Fox, Dr. Beddoe, Mr. Franks, Mr. F. Galton, Mr. E. W. Brabrook, Sir J. Lubbock, Sir W. Elliot, Mr. C, R. Markham, Mr. E. B. Tylor, Mr. J. Evans, and Mr. F. W. Rudler be reappointed a Committee for the purpose of preparing and publishing brief forms of instruction for tra- yellers, ethnologists, and other anthropological observers ; that Colonel Lane Fox be the Secretary, and that the sum of £25 be placed at their disposal for the purpose. : That Colonel Lane Fox, Professor Rolleston, Mr. Park Harrison, Mr. T. liv : REPORT—1876. H. Price, and Mr. J. R. Mortimer be a Committee for the purpose of the Exploration of Ancient Earthworks and other Prehistoric Remains ; that Colonel Lane Fox be the Secretary, and that the unexpended balance of £25 be placed at their disposal for the purpose. That Dr. Farr, Dr. Beddoe, Mr. Brabrook, Sir George Campbell, the Earl of Ducie, Mr. F. P. Fellows, Colonel Lane Fox, Mr. F. Galton, Mr. Park Harri- son, Mr. J. Heywood, Mr. P. Hallett, Professor Leone Levi, Sir Rawson Raw- son, and Professor Rolleston be a Committee for the purpose of continuing the collection of observations on the Systematic Examination of Heights, Weights, &c. of Human beings in the British Empire, and the publication of Photographs of the typical races of the Empire; that Colonel Lane Fox be the Secretary, and that the sum of £100 be placed at their disposal for the purpose. That the Right Hon. J. G. Hubbard, M.P., Mr, Chadwick, M.P., Mr. Morley, M.P., Dr. Farr, Sir George Campbell, M.P., Mr, Hallett, Professor Jevons, Mr. Newmarch, Mr, Shaen, and Mr. Macneel Caird (with power to add to their number) be continued as a Committee for the purpose of further developing the investigations into a Common Measure of Value in Direct Taxation; that Mr. Hallett be the Secretary, and that the sum of £10 be placed at their disposal for the purpose of defraying expenses incurred and to be incurred in the inquiry. That the Committee on instruments for measuring the speed of ships be reappointed ; that it consist of the following Members :——-Mr. W. Froude, Mr. F. J. Bramwell, Mr. A. E. Fletcher, Rev. E. L. Berthon, Mr. James R. Napier, Mr. C. W. Merrifield, Dr. C. W. Siemens, Mr. H. M. Brunel, Mr. W. Smith, Sir William Thomson, Mr. J. N. Shoolbred, and Professor James Thomson ; that Mr. J. N. Shoolbred be the Secretary, and that the sum of £50 be placed at their disposal for the purpose. That Professor Sir W. Thomson, Professor Clerk Maxwell, Professor Tait, Dr. C. W. Siemens, Mr. F. J. Bramwell, Mr. W. Froude, and Mr. J. T. Bottomley be a Committee for the purpose of commencing secular experi- ments on the Elasticity of Wires; that Mr. Bottomley be the Secretary, and that the sum of £100 be placed at their disposal for the purpose. Applications for Reports and Researches not involving Grants of Money. That the Committee, consisting of Professor Cayley, Mr. J. W. L. Glaisher, Dr. W. Pole, Mr. C. W. Merrifield, Professor Fuller, Mr. H. M. Brunel, and Professor W. K. Clifford, be reappointed to estimate the cost of constructing Mr. Babbage’s Analytical Engine, and to consider the advisability of printing tables by its means; and that Professor W. K. Clifford be the Secretary. That Dr. W. Huggins, Mr. J. N. Lockyer, Professor J. Emerson Reynolds, Mr. G. J. Stoney, Mr. Spottiswoode, Dr. De La Rue, and Dr. W. M. Watts be a Committee for the purpose of preparing and printing Tables of Wave- frequency (Inverse Wave-lengths); and that Mr. G. J. Stoney be the Secretary. That the Committee, consisting of Professor Sylvester, Professor Cayley, Professor Hirst, Professor Bartholomew Price, Professor H. J. S. Smith, Dr, Spottiswoode, Mr, R. B, Hayward, Dr. Salmon, Professor R. Townsend, Professor Fuller, Professor Kelland, Mr. J. M. Wilson, Professor Henrici, Mr. J. W. L, Glaisher, and Professor Clifford, for considering the possibility RECOMMENDATIONS OF THE GENERAL COMMITTEE. ly of improving the methods of instruction in elementary geometry, be reap- pointed. , That Mr. Spottiswoode, Professor G. G. Stokes, Professor Cayley, Professor H. J. S. Smith, Professor Sir W. Thomson, Professor Henrici, Lord Rayleigh, Mr, CG. Brooke, and Mr. J. W. L. Glaisher be appointed a Committee to report upon Mathematical Notation and Printing. That the Committee on the Magnetization of Iron, Nickel, and Cobalt, consisting of Professor Balfour Stewart, Professor Clerk Maxwell, Mr. H. A. Rowland, and Professor W. F. Barrett, be reappointed. That Professor Prestwich, Professor Harkness, Professor Hughes, Professor W. Boyd Dawkins, Rev. H. W. Crosskey, Messrs. L. C, Miall, G. H. Morton, D. Mackintosh, R. H. Tiddeman, J. E. Lee, T. Plant, W. Pengelly, and Dr. Deane be 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 Ireland, reporting other matters of interest con- nected with the same, and taking measures for their preservation; that the Rev. H. W. Crosskey be the Secretary. That the Rev. H. F. Barnes, Mr. C. Spence Bate, Mr, H. E. Dresser, Dr. Giinther, Mr. J. E. Harting, Dr. J. Gwyn Jeffreys, Professor Newton, and Rey. Canon Tristram be a Committee for the purpose of inquiring into the possibility of establishing a “close time” for the protection of indige- nous animals. ; That Mr. Spence Bate be requested to continue his Report “On the present state of our knowledge of the Crustacea.” - That Mr. R. Bruce Bell, Mr. J. Wolfe Barry, Mr. James Brownlee, Mr. Henry Brunel, Mr. St. John V. Day, Mr. Edward Easton, Mr. William Froude, Sir John Hawkshaw, Professor A. B. W. Kennedy, Dr. W, Pole, Mr. Hazelton Robson, Mr. David Rowan, and Mr. William Smith be a Committee for the purpose of reporting on the different kinds of Safety- valves used or designed for marine and other engines, That the Committee for the purpose of making experiments and of re- porting on the effect of the Propeller on the turning of Steam-yessels be re- appointed (with power to communicate with the Government), consisting of Mr. James R. Napier, Sir William Thomson, Mr, Wiliam -Froude, and. Professor Osborne Reynolds; that Mr. J. T. Bottomley be added to the Committee, and that Professor Osborne Reynolds be the Secretary. That the Committee, consisting of Professor Sir William Thomson, Major- General Strachey, Captain Douglas Galton, Mr. G. F. Deacon, Mr. Rogers Field, Mr. E. Roberts, and Mr. James N. Shoolbred, for the purpose of consider- ing the Datum-level of the Ordnance Survey of Great Britain, with a view to its establishment on a surer foundation than hitherto, with power to communicate with the Government if necessary, be reappointed; that Mr, James N. Shoolbred be the Secretary. That the Committee, consisting of Mr. W. H. Barlow, Mr. H. Bessemer, Mr. F. J. Bramwell, Captain Douglas Galton, Sir John Hawkshaw, Dr. C. W. Siemens, Professor Abel, and Mr. E. H. Carbutt, for the purpose of considering the use of steel for structural purposes, be reappointed ; that Mr. E. H. Carbutt be the Secretary. That Dr. A. W. Williamson, Professor Sir W. Thomson, Mr. Vincent Day,’ Dr. Siemens, Mr. Merrifield, Mr. Nelson Hancock, Professor Abel, Mr. R. Napier, Captain Galton, Mr. Newmarch, Mr. Carbutt, and Mr. Macrory be a Committee for the purpose of watching and reporting to the Council on Patent Legislation ; that Mr. Bramwell be the Secretary. lyi REPORT—1876. Resolution referred to the Council for consideration and action vf tt seem desirable. That the Council be requested to consider, and to take steps if they think it desirable, to urge upon H.M. Government the advisability of forming a. Museum of Scientific Instruments and Chemical Products, as suggested in the Memorial presented in June last to the Lord President of H.M. Council. That the arrangement of the Journal of Sectional Proceedings be altered, and that the list of the papers to be read on the day of issue be placed before the list of papers read on the previous day. That in future the Presidents-clect of the various Sections be invited to confer with the General Secretary, preparatory to the issuing of the first number of the Journal, to arrange the order in which the Sectional Addresses should be delivered, so as to afford opportunity to the Members of the Asso- ciation to attend the several Addresses in those subjects in which they may be interested, and that the order in which the Addresses are to be read be announced in the first number of the Journal. Communications ordered to be printed in extenso in the Annual Report of the Association. That Professor James Thomson’s paper, “‘ Improved Investigations on the Flow of Water through Orifices, with objections to the Modes of Treatment commonly adopted,’’ be printed in extenso in the Reports of the Association. That Mr. W. J. Janssen’s paper, “Nitrous Oxide in the Gaseous and Liquid States,” be printed in eatenso in the Reports of the Association. That the paper by Mr. G. Chrystal and Mr. 8. A. Saunder, “On a Com- parison of the B.A. Standards of Electrical Resistance,” be printed i extenso among the Reports. That the paper by Professor Osborne Reynolds, “On the Investigation of the Steering-qualities of Ships,” be printed in ewtenso in the Reports of the Association together with the necessary Plates. SYNOPSIS OF GRANTS OF MONEY. lvii Synopsis of Grants of Money appropriated to Scientific Purposes by the General Committee at the Bristol Meeting in September 1876. The names of the Members who would be entitled to call on the General Treasurer for the respective Grants are prefixed. Mathematics and Physics. *Kyerett, Professor.—--Underground Temperature............ £50 *Stokes, Professor.—Reflective Power of Silver and other BameEROR (FEC WED): Wier cc ens cet e tee en sane Thomson, Sir William.—Measurement of the Lunar Disturb- BICEIOL GRAVILY. |. see dracima nh. Bay Hee: Pe arinneayy 50 *Tait, Professor.—Thermo-Electricity (renewed) .......... 50 *Cayley, Professor.—Publication of Tables of Elliptic Functions 250 *Joule, Dr.—Dctermination of the Mechanical Equivalent of EURO cgi eo. 0's. srsaesesl iO. O10 Magnetical Observations eocsseoee 185 13 9 ‘£1546 1 16 4 1841. Observations on Waves........... - 380 0 0 Meteorology and Subterranean Temperature ......... Saeceseosene 8 8 0 Actinometers........+... cssssreereee 10 0 0 Earthquake Shocks ...... isssevess 17 7. 0 Acrid Poisons,...........04. Reeubuans 6 0 0 Veins and Absorbents ............ 3 0 0 Mud in Rivers ............... we 5 0 O Marine Zoology......ssseeseceeewee 15 12 8 Skeleton Maps ....scsscssseseees .. 20 0 6 Mountain Barometers ............ 618 O Stars (Histoire Céleste)........... 185 0 0 REPORT—1876. Ix & 3, a. Stars (Lacaille) ..s.ccccceeee 79 5 0 Stars (Nomenclature oy scvsassterein Lo & 6 Stars (Catalogue Of) ....c00e00000. 40 0 0 Water on [ron ....cceeeeeeeeeeeeeee 50 0 0 Meteorological Observations at IMVErNeSs ...isecccoeesesceee ose 20 0 0 Meteorological Observations (re- duction Of) sseccccsssecereeeeree 25 0 0 Fossil Reptiles .2..sesescseseeeeeeee 50 0 0 Foreign Memoirs ......+++-.000e oe 62" (OLO Railway Sections ......++.+. Suaeee das io hettd) Wael Forms of Vessels ...+++ Weise 19ST12Z* 0 Meteorological Observations at Plymouth ......+ ceraeeene peeaes Seis 0 Magnetical Observations ......... 61 18 8 Fishes of the Old Red Sandstone 100 0 0 Tides at Leith ......+00.. aye PSO ORD Anemometer at Edinburgh ...... 69 1 10 Tabulating Observations ......... 9 6 38 Races of Men esscecesseseeee eeees 5 FOO Radiate Animals ws... 2 0 0 £1235 10 11 1842. Dynamometric Instruments ..... = Si Anoplura Britannia ......+++.+0+. . 5212 0 Tides at Bristol........eeeseeee sears eo) oO Gases on Light ......sesseeeeseees as 0. Ma Ey, Chronometers .....++5 S500 ee Wad Marine Zoology.......s.+++ sepaeiee Geel? toa British Fossil Mammalia .....,... 100 0 0 Statistics of Education ........... eee2G* hONTD Maxine Steam-vessels’ Engines... 28 0 0 Stars (Histoire Céleste).........06 59 0 0 Stars (Brit. Assoc. Cat. of ) ...+.. 110 0 0 Railway Sections ......... wetsee eee LO Ole 10 British Belemnites....... qeecnsitseit 50 0 0 Fossil Reptiles (publication of Report) ......eeeeeee “fuounccat enc 210 0 0 Forms of Vessels ese.sesseseeeeeees 180 0 0 Galvanic Experiments on Rocks 5 8 6 Meteorological Experiments at Plymouth .......secseeeeeeeeeeees 68 0 0 Constant Indicator and Dynamo- metric Instruments .......++ coor STO RO Force of Wind «.......00s. vescccess aeOeOn. 0 Light on Growth of Seeds .... 8 0 0 Vital Statistics ......... Sicesotssecs “tO N0)- (0 Vegetative Power of Seda’ saci) lesa alt Questions on Human Race ..... ED! 0: £1449 17. 8 1843. Revision of the Nomenclature of Stars’. .csesees peckusseteseniaesseee 2 0 0 Reduction of Stars, British Asso- ciation Catalogue ...-++..+-.s00e 25 0 0 Anomalous Tides, Frith of Forth 120 0 0 Hourly Meteorological Observa- tionsat KingussieandInverness 77 12 8 Meteorological, Observations at Plymouth .......000es ccscesceee OD 0 OD Whewell’s Meteorological Ane- mometer at Plymouth ..... 10 0 0 pe Pa Meteorological Observations, Os- ler’s Anemometerat Plymouth 20 0 0 Reduction of Meteorological Ob- SEVVALIONS .....ccecceeeee Sanvecasi JOOS ODEO Meteorological Tnstruments and Gratuities ecsvccceccssces Nccssesse ODD eU Construction of Anemometer at INVernesS .,.cscccccccccesssesenes 00 12) 2 Magnetic Cooperation scnsecsedes 10 8 10 Meteorological Recorder for Kew Observatory seeeeeseene secvessnseeO Owe Action of Gases on Light ........ 18 16 1 Establishment at Kew Observa- tory, Wages, Repairs, Furni- ture and Sundries .......+0+. sone 1834.08 Experiments by Captive Balloons 81 8 0 Oxidation ofthe Rails of Railways 20 0 0 Publication of Report on Fossil Reptiles......+ Seessiep Suuskueeuae «| 40,0 0 Coloured Drawings of Railway SECEIOMS’...scnscs erscotcasnep ones 147 18 3 Registration of Earthquake Shocks ...,0cevs.seees Rorepdcne =) 0) 050 Report on Zoological Nomencla- TUTE | owerssronsersccosccscese ceosee, 1050 0 Uncovering Lower. Red Sand- stone near Manchester ....+.++ ‘ney pe Vegetative Power of Seeds ..... 5 3 8 Marine Testacea (Habits of) ... 10 0 0 Marine Zoology..-..sssseeeee Sones sey MLOERO ED Marine Zoology....eersseeseeesereee 2 14 11 Preparation of Report on British Fossil Mammalia ...sescceserees 100 0 0 Physiological Operations of Me- dicinal Agents ...cseccssscereeee 20 0 0 Vital Statistics ......+06. spelawivivsites aancG matey me Additional Experiments on the Forms of Vessels ...secssseeeeee 70.0 0 Additional Experiments on the Forms of Vessels ... .....0000+ - 100 0 0 Reduction of Experiments on the Forms of Vessels ..-..+0++ Savaste 100 0 0 Morin’s Instrument and Constant Indicator pisesnmasstusdsadsbatwareee 69 14 10 Experiments on the Strength of Materials ...cccssseceesceoves 60 0 0 £1565 10 2 1844, Meteorological Observations at Kingussie and Inverness ...... 12 0 0 Completing Observations at Ply- mouth ....... woacdbencceserpners Prt oh ilies Magnetic and Meteorological Co- OPEFAatlON - wewsnscrteusconses eooee 2D § 4 Publication of the British Asso- ciation Catalogue of Stars...... 35 0 0 Observations on Tides on the East coast of Scotland ........ Fe OU NU Revision of the Nomenclature of Stars ...cscvccsccscccecees 1842 2 9 6 Maintaining the Establishmentin Kew Observatory ....sseeeeeeeee 117 17 3 Instruments for KewObservatory 56 7 38 Sa bah. teE Influence of Light on Plants...... 10 0 0 Subterraneous Temperature in IPCIBMG Vaassesteucesasessdstceseese tsi pO" 'O Coloured Drawings of Railway SECLIONS ..ccccccssceceaccors sesrecs OLE Investigation of Fossil Fishes of the Lower Tertiary Strata ... 100 0 0 Registering the Shocks of Earth- TAMER aeccccccscconscacceeslSAa 29 11 10 Structure of Fossil Shells ......... 20 0 0 Radiata and Mollusca of the /Bgean and Red Seas......1842 100 0 0. Geographical Distributions of Marine Zoology .........1842 10 0 0 Marine Zoology of Devon and OMG WAll” scv.cunedesesscesccesere op lU, 0, 0 Marine Zoology of Corfu ..... w 10 0 0 Experiments on the Vitality of Seeds ....... veveee santteeceanecany pine) ts Uario Experiments on the Vitality of MECOSiUsssessarcscisivessas eel O4D oy Suan Exotic Anoplura ......sc0000084 15 0 0 Strength of Materials .......0... 100 0 0 Completing Experiments on the Forms of Ships .......seseeeeeeee 100 0 0 Inquiries into Asphyxia ......... 10 0 0 Investigations on the Internal Constitution of Metals ..... wapopeco Ulmer Uae O Constant Indicator and Morin’s Instrument ...seesseeeeeee1842 10 38 6 ‘ £981 12 8 1845. Publication of the British Associa- tion Catalogue of Stars ........ . 851 14 6 Meteorological Observations at Inverness .....+. eddagssaseenselce 30 18 11 Magnetic and Meteorological ‘Co- OPEFatiONn ceeccescececscsceoes seco 161698 Meteorological Instruments at Edinburgh ........scsecsesosesees Meelhe 9 Reduction of Anemometrical Ob- servations at Plymouth ...... .. 25 0 0 Electrical Experiments at Kew Observatory vccesececsesereees viata ula 21S Maintaining the Establishment in Kew Observatory .....+00+....6. 149 15 0 For Kreil’s Barometrograph...... 25 0 0 Gases from Iron Furnaces ...... 50 0 0 The Actinograph .......0c0.00 15 0 0 Microscopic Structure cf Shells 20 0 0 Exotic Anoplura .......00... 1843 10 0 0 Vitality of Seeds ............1843 2 0 7 Vitality of Seeds ............ 1844 7 0 0 Marine Zoology of Cornwall ... 10 0 0 Physiological Actionof Medicines 20 0 0 Statistics of Sickness and Mor- BEBE Ve NOLIC 'cccancnenennches <4 20 0 0 Earthquake Shocks ,,....... 1.1843 15 14 8 £330 9 9 GENERAL STATEMENT. lxi 1846. British Association Catalogue of Stars ccccsoccsssevecsvsesee.1044 21115 0 Fossil Fishes of the London Clay 100 0 0, Computation of the Gaussian Constants for 1829 ......0... 50 0 0 Maintaining the Establishment at Kew Observatory ......+++ beet ee 146 16 7 Strength of Materials .........+. »- 60 0 0 Researches in Asphyxia ........ 616 2 Examination of Fossil Shells...... 10 0 0 Vitality of Seeds ....0+......1844 2 15 10 Vitality of Seeds ........ 1845 7:12 8 Marine Zoology of Cornwall...... 10 0 0 Marine Zoology of Britain ..... @ POC Ore0 Exotic Anoplura .....+..000. 1844 25 0 0 Expenses attending Anemometers 11 7 6 Anemometers’ Repairs ....... Manes Lara cue O Atmospheric Waves ......0.. 38 38 3 Captive Balloons .......00... 1844 819 3 Varieties of the Human Race 1844 7 6 3 Statistics of Sickness and Mor- talibyein), VOLK. ta 0 ooh ad Trish Taviedts ope aenes causpon op ber 5.0 0 a 1855. Manure Experiments ....... oosnaly we) Maintaining the Establishment at British Meduside wc. 5 0 0 Kew Observatory ...... secssese, 425 0 0 Dredging Committee......... Rall rig o Earthquake Movements ...... +» 10 0 01 Steam-vessels’ Performance ...... 5 0 0 Physical Aspect of the Moon....... 11 8 5 Marine Fauna of South and West Vitality of Seeds ........cesccoeeee 10 7 11 of Ireland ...ccccccceccee i Min teen ety Map of the World... 15 0 0 Photographic Chemistry wbupbecaet) meni Ethnological Queries. wee 5 0 0 Lanarkshire Fossils ............ sacl ee Dredging near Belfast ............ 4 0 0 Balloon’ ASeents: ...cscccncseoan siete 39 11 0 bo a le £684 11 1 1856. 1860. ; Maintaining the Establishment at Maintaining the Establishment Kew Observatory :-— | of Kew Observatory............. 500 0 0 AS54, ne lo. 7 0 575 00 | Dredging near Belfast............. 16 6 O 1855......£500 0 0 Ay | Dredging in Dublin Bay..cccssoscs 15, 90 tO GENERAL STATEMENT, fi 5 S 8. ad Inquiry into the Performance of Steam-vessels...csscssscseeseseee 124 0 0 Explorations in the Yellow Sand- stone of Dura Den............... 20 0 0 Chemico-mechanical Analysis of Rocks and Minerals... 25 0 0 Researches on the Growth of PIBDEGiisccssesescsccssesessssssaiss 10), 0..,0 Researches on the Solubility of RAILS Va dsnavesssdneanes cars ceetsaseric GO) OvyO Researches on the Constituents Of Manures..ccccssscereserereeese 25 0 0 Balance of Captive Balloon Ac- COUNES,.,sreccccevecscesccesnsssess 1 13 6 £1241 7 0 1861. Maintaining the Establishment of Kew Observatory ............ 500 0 0 Earthquake Experiments......... 25 0 0 Dredging North and East Coasts of Scotland....... AMRRESES 0c scasee 23 0 O Dredging Committee :-— 1860 .....°£50 0 0) . thet 0. ee ee ee Excavations at Dura Den......... 20 0 0 Solubility of Salts ...........ceeeees 20 0 0 Steam-vessel Performance ...... 150 0 0 Fossils of Lesmahago .......+... 15 0 0 Explorations at Uriconium ..... . 20 0 0 Chemical Alloys .........ssseeeeee 20 0 0 Classified Index to the Transac- TUBHS Van dete cess ceccsacvevecesesans - 100 0 0 Dredging in the Mersey and Dee 5 0 0 Dip Circle w......seesssvevssssssees 30 0 0 Photoheliographic Observations 50 0 0 Prigon Diet wtcccccsscesseessseseese 20 0 0 Gauging of Water..............0... 10 0 0 Alpine Ascents ..... svabastetrasnee 0 5 Constituents of Manures ....,.... 25 0 0 £1111 5 10 1862. Maintaining the Establishment of Kew Observatory ............ 500 0 0 Patent Laws .........+ ebissaks setae BGO Mollusca of N.-W. America...... 10 0 0 Natural History by Mercantile Marine ....... Sisveccvacdeasessses O10 @ Tidal Observations ...... sosarse 20" O18 Photoheliometer at Kew ......... 40 0 0 Photographic Pictures of the Sun 150 0 0 Rocks of Donegal ...........s.008 25 0 0 Dredging Durham and North- umberland.....secessesesssveessss 25 0 0 Connexion of Storms......... as 20 0 0 Dredging North-east Coast of DCOUlAN .c.issisaasesaia 6 9 6 Ravages of Teredo «.............. 38 11 0 Standards of Electrical Resistance 50 0 0 Railway Accidents .........45.. » 10 0 0 Balloon Committee ............45. 200 0 0 Dredging Dublin Bay ............ 10 0 0 Dredging the Mersey ...........5 5 0 0 Prison Diet ....:.......ccceeeees wo BOO 4 Gauging of Water.............005 1210 0 & 8. a, Steaniships’ Performance......... 150 0 0 Thermo-Electric Currents ...... 5 0 0 £1293 16 6 1863. Maintaining. the Establishment of Kew Observatory............ 600 0 0 Balloon Committee deficiency... 70 0 0 Balloon Ascents (other expenses) 25 0 0 ENtOZO@isi scp .sscirnpssecosbasetuans 25 0 0 Coal Fossils ......... desdesserewsd's oy 20) .O..0 BLOTPING Ss state veh cs save sssssimenie 20 0 0 Granites of Donegal... auaeieas . 5 0 0 Prison Diet............ sastessassrcds)) 20, '0,. 0 Vertical Atmospheric Movements 13 0 0 Dredging Shetland .....,.......4. 50 0 0 Dredging North-east coast of Scotland: .....csdsssivisisesseas’ 25). 0...0 Dredging Northumberland and Durham.....cs.ssseceeseeeeees we 17-3 10 Dredging Committee superin- GENMENCE Ss Spee evens: sssssisss 10 0 0 Steamship Performance ........ . 100 0 0 Balloon Committee ............... 200 0 0 Carbon under pressure..... ...... 10 0 0 Volcanic Temperature .;...... «.. 100 0 0 Bromide of Ammonium ......... 8 0 0 Electrical Standards............... 100 0 0 Construction and distribu- HDT sea Kees cn epaaatceideenn 40 0 0 Luminous Meteors ............065 17 0 0 Kew Additional Buildings for Photoheliograph ...... isesbabes 100 0 0 Thermo-Electricity ...... obsbbenes 15 0 0 Analysis of Rocks ....... eweseduy 8,.0,.0 Hydroida .....:.ssseessvvoevere wo. 10 0 0 £1608 3 10 1864. Maintaining the Establishment of Kew Observatory............ 600 0 0 Coal Fossils .....:......... sossennse 20 0 0 Vertical Atmospheric Move- THOME wes acnesiecvass sue sressereeee 20 0 0 Dredging Shetland ............ -- 79 0 0 Dredging Northumberland ..,..,, 25 0-0 Balloon Committee ............... 200 0 0 Carbon under pressure............ 10 0 0 Standards of Electric Resistance 100 0 O Analysis of Rocks.............00... 10 0 0 FU VGEOUGR ~..csseerevnceetescees tes LUDO Askham’s Gift .............., coeee 590 0 O Nitrite of Amyle ...........,...00 10 0 0 Nomenclature Committee ...... 5 0 0 Rain-Gauges ......... tecosessssocenee 1915 8 Cast-Iron Investigation aasex sph) eat) JO Tidal Observationsinthe Humber 50 0 0 Spectral RAYS. oo. is...sceceesensee 45 0 0 Luminous Meteors ............... 20 0 0 i £1289 15 8 1865. Tae Maintaining the Establishment of Kew Observatory............ 600 0 @ Balloon Committee ............... 100 0 0 Ixiv & 48.98. Rain-Gauges ...05 sssesseseneseeeeee 30 0 0 Tidal Observationsinthe Humber 6 8 0 Hexylic Compounds...........++++ 20 0 0 Amy] Compounds..........++++++ an2z0 20 40 Trish Flora ...cesseeseeeeeees see neo 20 20 American Mollusca ....... Re ZI QO Organic ACidS .........ssseeseeeeee 20 0 0 Lingula Flags Excavation ...... 10 0 0 Eurypterus .........0+. Saas ites 50 0 0 Electrical Standards......:....0+++ 100 0 O Malta Caves Researches ......... 30 0 0 Oyster Breeding .......s0..sseeeee 25 0 0 Gibraltar Caves Researches...... 150 0 0 Kent’s Hole Excavations...... .. 100 0 0 Moon’s Surface Observations... 35 0 0 Marine Fauna ........ceseeseeeeees 25 0 0 Dredging Aberdeenshire .......-. 25 0 0 Dredging Channel Islands ...... 50 0 0 Zoological Nomenclature......... 5 0 0 Resistance of Floating Bodies in Water ...... Bie eececeoe 100 0 0 Bath Waters Analysis ............ 810 0 Luminous Meteors .........s.000 40 0 0 £1591 7 10) 1866. Maintaining the Establishment of Kew Observatory............ 600 0 0 Lunar Committee...........00008 64 13 4 Balloon Committee ..........seeee 50 0 0 Metrical Committee.........0... 50 0 0 British Rainfall....... deieockeanve 50 0 0 Kilkenny Coal Fields ............ 146 0 0 Alum Bay Fossil Leaf-Bed ...... 15 0 0 Luminous Meteors ...........006 50 0 0 Lingula Flags Excavation ...... 20 0 0 Chemical Constitution of Cast MOMMIES. ss 5 os cicsisnisseseisislnes 50 0 0 Amy] Compounds...........-00s04+ 25 0 0 Electrical Standards..,..........+ 100 0 0 Malta Caves Exploration......... 30 0 0 Kent’s Hole Exploration ......... 200 0 0 Marine Fauna, &c., Devon and Cornwall’ ......... Reseevere eben 25 0 0 Dredging Aberdeenshire Coast... 25 0 0 Dredging Hebrides Coast......... 50 0 0 Dredging the Mersey ............ 5 0 0 Resistance of Floating Bodies in IWALCLp eceenssscssrersscnsacecnsus 50 0 0 Polycyanides of Organic Radi- GAS jappeemotacoade usehonuesac io 20 Ow RAP OU MOTIS soisessesshoar espater 10 0 0 (nis PATINEIGR )..secspesssonedip ess 15 0 0 Catalogue of Crania ...........-4++ 50 0 0 Didine Birds of Mascarene Islands 50 0 0 Typical Crania Researches ...... 30 0 0 Palestine Exploration Fund...... 100 0 0 £1750 13 4 1867. Maintaining the Establishment of Kew Observatory............ 600 0 0 Meteorological Instruments, Pa- Testime seercssse sence 50 0 0 Lunar Committee........+. Serosener Lao aenOen LC REPORT—1876. £1940 mlocoornoocoocoecocococes — a) oo oooococoeco eocoooocoececoeo ole oo oooococoecoo cooocoocoeocococo eclococoocoocoocooscoooocoecoN £ Metrical Committee..........:..6. 30 Kent’s Hole Explorations ...... 100 Palestine Explorations.......«.... 50 Insect Fauna, Palestine ...:..... 30 British Rainfall...........++6+ Witieniod Kilkenny Coal Fields .......0... 25 Alum Bay Fossil Leaf-Bed ..... . 25 Luminous Meteors .......... ee) Bournemouth, &c. Leaf-Beds... 30 Dredging Shetland ............00 75 Steamship Reports Condensation 100 Electrical Standards.............-. 100 Ethyle and Methyle series ...... 25 Fossil Crustacea ..... chbeneeee Svar 25 Sound under Water ...........4+. . 24 North Greenland Fauna ........ al 40 Do. Plant Beds ... 100 Iron and Steel Manufacture 25 Patent Laws \v..\.cserseresresmneee aU £1739 1868. Maintaining the Establishment of Kew Observatory............ 600 Lunar Committee....... seces 120 Metrical Committee......... sinsa ee Zoological Record ............-.- 100 Kent’s Hole Explorations ...... 150 Steamship Performances......... 100 British Rainfall .......... tosses Luminous Meteors .... 50 Organic Acids ....... 60 Fossil Crustacea ...sessesccessssee 20 Methyl series ......... AaRCAMSsEC Seieeed) Mercury and Bile..........00..00++ 25 Organic remains in Limestone ROCKS puacercccses ces eeradke en ua nee Scottish Earthquakes ............ 20 Fauna, Devon and Cornwall ... 30 British Fossil Corals..............- 50 Bagshot Leaf-beds ..........46+ « 50 Greenland Explorations ......... 100 Fossil Flora; ccavsseatspeocrsaccwess ed Tidal Observations ............... 100 Underground Temperature ...... 50 Spectroscopic investigations of Animal Substances ....... eee ub Secondary Reptiles, &c. ......... 30 British Marine Invertebrate Paina ssersecsseseqneene deastmseOe 1869. Maintaining the Establishment of Kew Observatory......... ... 600 Lunar Committee .....ssseeeeseeee 50 Metrical Committee............++. 25 Zoological Record........-s0+0++0+ 100 Committee on Gases in Deep- well Water is .cgcsssessemmqneese 25 British Rainfall... 7:.....-» oo and 36. a G AD ee ne crarcret cata ai « 5, 6, 43, and 29. Of the first six, all except 57, which we have not measured, are mentioned at p. 146 of the Reports, but none of them have proper labels. All, however, were marked in some way or other so as to be identifiable. Of the last three all have labels, which are complete in 6 and 43. Nos. 6 and 29 do not appear in the Reports. The temperature on 43, which does appear, agrees, with that given on p. 146. We used 29 as a companion middle coil to 43, because its variation-coefficient was small and nearly equal to that of 43; but otherwise we have not bestowed much care on it. a Coils measured.—The coils which we have measured are, therefore, 2, 3, 58, 35, 36, 29, 43. These we call for convenience A, B, ©, D, H, F, G. The normal coil is the flat coil at 10° Centigrade. This temperature is chosen because it was the lower limit of the temperature of the tap-water, which varied on different days from 10° to 12°, though if was very constant during a good part of any one day. As far as our experience went, the use of a stream of tap-water was the best as well as most convenient way of reducing the coils to a known temperature *. Results of comparison: the first statement.—The following Table exhibits our results in the way which lies nearest the method by which they were ob- tained :— R stands for resistance of flat coil at 10° C. x . Ai of the respective coils A, B, &e. at 10°C. r a variation-coeificients. \Greatest devi-| Geentest ps Coil. r. No: of results |" ation from || R—X. No. of results|" stion from of whichmean. of which mean. mean. mean, Flat coil. | 34 A 197 5 4 867 5 19 B 200 3 2 811 3 3 Cc 95 6 6 159 2 2 D 401 10 5 2071 5 24 BR 393 3 4 1954 3 8 F 28 1 ae —82 1 oe G 35 4 2 —57 2 0 Second statement.—The above is the most convenient form of representing our results; but for the sake of comparison we give also the following (Y now stands for the resistance of the coils A, B, C, &c., at the temperatures, or at some one of them, given at p. 483, B.A. Report, 1867 T) :— * One of us, in endeavouring to find the conductivity of paraffin, has since found that the temperature of a wire imbedded in a much greater thickness of paraffin than there is in the B.A. coils, reaches the temperature of the tap-water in considerably less than an hour, the paraffin-jacket having been at a temperature of about 30° throughout to start i : + Reprint, p. 146. 3 with. 1876. c 18 REPORT—1876. Coil. | Lemp. in Report. R-Y. A 16:0 —315 B 158 —349 Cc 15:5 —344 D 15:7 —215 E 157 — 286 G 15-2 — 239 It will thus be seen that Band C are practically equal at the temperatures given, while A does not differ very much from these. D and K are not very different inter se, but differ somewhat from the first three; while G, con- sidering its small coefficient, is considerably out. Statement of standard temperatures.—If we cousider B and C to be right at the temperatures given above and reduce the others so as to be equal to them, we should get the following Table of standard temperatures :— Coil. Standard temp. ° A 161 B 158 C 15:3 D 16:0 E 158 F 19-4 G 18:2 Results of control eaperiments——In the next place we give the results of our control experiments, in which the several coils were nursed to tempera- tures very near those given in the Report, and then compared with each other. The small deviations from the temperatures in the Report arise from thermometer corrections. The differences thus found are given side by side with those calculated from the data given above ; the differences are given in the next column, and in the last the greatest possible difference, owing to an error of 0° 1 C. in temperature determination. Coils. | Temp. Calculated.|Observed.) Difference. eee ° | A 1589 || B—A 34 20 +14 40 B 1569 | C—A 42 19 +23 29 C 15:20 | B—C —8 +2 —10 29 D 1559 || C—D 163 180 —-17 49 E 1549 || C—E 132 119 +13 48 F 13:45 || E—D 31 70 —39 79 G 15-11 C—@G 100 102 — 2 13 | G—D 63 43 +20 44 | C-G 100 108 — 3 18 C—F 156 150 + 6 12 G—F 56 50 + 6 on It appears, therefore, that the differences between the observed and calcu- lated values are always less than what would arise in the most unfavourable case, owing to an error of 0°1 C. in the temperature determinations. ON THE THERMAL CONDUCTIVITIES OF CERTAIN ROCKS. 19 Rough comparison of coefficients with Matthiessen’s—It is perhaps worth while to give the following rough comparison between the results for the variation-coeflicients which we have obtained in the neighbourhood of 10° C. with the mean results of Matthiessen. Per cent. increase per 1° C, | Matth. 215d bade ne) Eee are 150 | 059 Ad amen hapa “Og 4-s| 065 Bi ENT 300 || +295 Leet } Bie { Toes, Wes, tet There is no striking difference except in the case of Pt Ir, where the alloy of which the coil is made must approach much nearer a pure metal than Matthiessen’s alloy (33°4 per cent. iridium) did. Discrepancy in Coil G with former measwrements——The only other point to which we have to call attention is the discrepancy between former and present measurements in the coil G, whose resistance seems to have gone down since it was last tested. In conclusion we venture to suggest two alterations in the construction of standard coils, which, as far as our experience goes, would be improvements. First, to make them flat instead of cylindrical. This would facilitate stirring when the coils are immersed in any liquid. Secondly, to insert as near the wire as possible a properly insulated junction of a thermoelectric couple, the other junction of which should be fastened on the outer case of the coil. Several of these fitted to each coil would do away with a great deal of the trouble and uncertainty attending the temperature determinations required in comparing and copying standards. Third Report of a Committee, consisiing of Prof. A. S. Hurscuet, B.A., F.R.A.S., and _G. A. Lesour, F.G.8., on Experiments to determine the Thermal Conductivities of certain Rocks, showing especially the Geological Aspects of the Investigation. Tux object originally proposed by the Committee was to arrange and classify the most commonly occurring rocks experimentally according to their powers of conducting heat; and it has hitherto been so far successfully attained that the thermal conductivities of an extensive series of ordinarily occurring rocks have been shown to differ from each other on a very strongly marked scale of gradation, which it was endeavoured to represent graphically in the Com- mittee’s last Report by a series of ascending steps of absolute thermal resist- ance, or resistance to the passage of heat offered by the different rocks. To every 200 units of this ascending scale a new letter of the alphabet, starting with A for the interval 0-200 of absolute resistance, was assigned ; the values of the resistances were shown graphically, and the various rocks that arrange themselves under the several classes so formed could be readily discerned. By adopting this graphical mode of representation the values of certain eZ 90 REPORT—1876. thermal resistances observed during the past year and communicated in this Report may be exhibited with equal clearness, and an easy comparison may by this means be made of the values found in this and last year’s series of experiments where the same rock-specimens, or specimens of very closely allied kinds of rock, were submitted in the former and in this year’s series to examination. A slight change, however, is here introduced in briefly describing the results obtained numerically, by employing, instead of the sig- nificant figures of those results (as was done in the last Report), the tenth part of them as a brief expression for the absolute thermal conductivity. Thus the absolute thermal conductivity of galena in the present list being 0-00705 in centimetre-gramme-second units, hitherto described for brevity by its significant figures 705, will be spoken of in this Report as 70-5, to which the meaning may conveniently be attached that 70°5 gramme-degree units of heat per second pass through a plate of galena one centimetre thick, having an area of one square metre, for a temperature-difference of one degree be- tween its faces. The method of investigation without the use of a thermopile has hitherto proved unsuccessful, no soft material capable of effecting a close junction with the rocks having yet been found of sufficiently constant resistance to afford a useful standard of comparison with them when the rocks are intro- duced between its layers; but the progress of the investigation has shown that a simple water-film (if it could be preserved from drying off with porous rocks) effects a complete junction between them and any impervious surface, as that of caoutchouc, against which they are pressed. A similar film of oil, it appears from some experiments recorded in the present list, is less effective for the purpose ; and to ensure a constant water-film in which the thin wires of the thermopile could be placed, pieces of well-soaked bladder kept soft in water rendered antiseptic with carbolic acid were laid on the india-rubber faces of the boiler and cooler, so as to press the thermopile-wires against the rock with a constantly moist and uniformly wet surface. The duration of an experiment and the temperature to which they were exposed (usually be- tween 100° and 120° F.) were never so great as to cause the bladders to approach dryness before the termination of the experiment. The proportion of moisture absorbed by the rocks (when sensibly porous) was ascertained, and it was always such a small fraction of that imbibed by the same rocks thoroughly soaked in vacuo that it probably exercised a scarcely sensible influence on the results. Its amount, and that of the full quantity of water absorbable by the porous rocks tested, is stated in the list; and from the corresponding alteration of the observed conductivity some idea of the pro- bable correction necessary to be applied for the presence of moisture in some of the porous rocks during the process of the experiment may be obtained. The two chief defects of the thermopiles used hitherto had been their thickness (making them intrude too far from the rock-surface into the badly conducting strata with which it is in contact), and the false thermoelectric currents proceeding from irregularities of material and internal condition of the wires subjected to great varieties of temperature along their length. To diminish the former source of error, wires less than half a millimetre (0:40 millim., or , inch) in _diameter were used and neatly soldered at the junctions ; and to counteract as far as possible the remaining evil, they were chosen of the most dissimilar metals (iron and German silver), and twelve junctions above and twelve below the rock-plate formed a continuous circuit giving a very strong thermoelectric current. The whole resistance of the circuit (including the 20 ohms usually added to bring its indications con- veniently within the scale of a Thomson’s reflecting galvanometer) was 40 ON THE THERMAL CONDUCTIVITIES OF CERTAIN ROCKS. 21 ohms when the wires were coupled for observing a difference of temperature ; and it was assumed that, with this resistance and with the probable tendency of twelve wires similarly circumstanced to neutralize each other’s false effects, no sensible errors from local disturbances would arise. The instrument was submitted to some careful tests, with a result that, at the highest temperatures of the experiments, errors in the temperature-difference amounting to about 1° F. may have been committed. At the ordinary temperatures of the wires between 100° and 120° F. it was found, by substituting a heated iron disk (coated on the faces with thin paper) in the place of a rock-plate, so as to heat both sets of wires equally, that the only permanent deviations produced as the plate sunk very slowly in temperature also sunk gradually with it from an equivalent value of about 7° to about 3° upon the scale. As the correct- ness of the small temperature- -differences (of 6° and upwards) lying usually between the above two temperatures was thus fairly checked, and for exception- ally higher differences and temperatures the conditions could not easily be more exactly assimilated to those of the actual experiments so as to control and estimate them, the effects of these small errors have not been further regarded in the calculations ; but in order to avoid changes of value in the divisions of the scale, and to enable the actual temperature of each set of wire-junctions to be directly observed, an arrangement of the thermopile was made by which each set of junctions could be separately combined with a similar set in con- tinuous circuit with the galvanometer placed in a small rectangular water- bath. The latter is made of tin, and, as well as its lid, is well jacketed with cork, and provided with an agitator; so that by adding hot or cold water, which can be withdrawn below, any temperature of the water in the bath can be obtained. A simple commutator enables the circuit with the galvano- meter to be closed, either through the two principal sets of junctions or through one of them and through a set corresponding to it in the bath ; that by changing the temperature of the latter until no current passes pinnae the circuit the actual temperature of each rock-face could be observed. This mode of observation is free from all objections, excepting those of false currents arising in long wires and plates of the same metal maintained at very various temperatures ; but with the exception of the twelve loops of German-silver wire projecting on one side from the rock-plate, the corre- sponding loops on the other side, and all the rest of the circuits made to the galyanometer, were formed from the same piece of iron wire freshly annealed. The comb-like teeth of the commutator are pieces of narrow hoop-iron about 3 inches long, closely set together in wood, and also thoroughly annealed, to which the proper terminals of iron wire are soldered at their feet, while the upper ends are filed to chisel-edges ; and a small hand-rack of iron wedges set on wood at proper distances apart, thrust between them in different positions, completes the connexion in the three different orders that are required. The additional branch wires used in the arrangement are few, and, as will be seen from the following description, add very little to the total lengths of iron wire which conduct the currents. The twelve-turn coil of wire in which the rock is pressed consists of twelve half-turns or loops of German silver and the same number of iron loops. The twelfth loop of German silver (see figure, p. 22) completes the circuit or connexion from the beginning to the end of the coil through the medium of the galvanometer. There are thus twelve junctions of dissimilar metals above, and twelve below the rock- plate in a closed circuit with the galvanometer. To produce a new set of twelve junctions corresponding to each of these, the loops of German-silver wire are all cut through in the middle, and the free ends soldered to twenty- four short pieces of iron wire, the junctions being laid side by side across a 22 REPORT-—— 1876. narrow water-tight trough formed of three or four rectangular washers of caoutchouc laid on a sheet-caoutchouc floor, upon which the sides of the rectan- gular tin bath, open at the top and bottom, are pressed down. The tin bath is 5 inches long (the same as the width of the rock-sections), nearly the same height, and 2 inches wide; and it is provided with a false bottom, through the perforations of which the water reaches the wires, and is kept agitated above by a thermometer passing through a longitudinal slit in the lid and attached to a small tin blade, without injuring them. The twenty-four extremities of iron wire projecting 1 or 2 inches beyond the bottom of the bath are there soldered to the feet of twenty-four teeth of the commutator, and the twelve iron wedges of the hand-rack being inserted between the points of these teeth, completes the circuit-connexion in the ordinary way for observing a difference of temperature between the two principal sets of junctions of the thermopile. As a proof of the trustworthy action of the instrument, it may be mentioned that when, in the course of an experiment, the reading of the galvanometer with the thermopile thus joined up was being noted, and water of various temperatures from 60° F. to 160° F. was poured into the bath where the twenty-four supplementary junctions are placed and are all included in the circuit, not the smallest effect was pro- duced upon the reading as soon as the water in the bath had by gentle agitation become uniform throughout in temperature. Not only are the two opposing sets of twelve junctions heated in the bath on the average all of exactly equal force, so as to balance each other, but the false currents, which in such ranges of temperature must be evoked with sensible intensity if any of them should prevail, either neutralize each other exactly or are entirely absent, as it appears equally probable to conjecture, in this portion of the apparatus. As regards formation of the circuit through one of the principal sets of junctions only, accompanied by a corresponding set of junctions in the bath, this is accomplished as is represented in the annexed outline sketch, where two pairs of junctions only (a b, a’ b'), above and below the rock- plate, are shown, thin lines represent- ing iron and thick lines German-silver wire. B is the bath in which the supplementary junctions, s'sss’, ob- tained by severing the loops of German- silver wire, as at ss, are immersed. The two extreme half-loops and cor- responding teeth of the commutator serve to complete the circuit with the galyanometer; and the arrangement for every additional severed loop of German-silver wire introduced be- tween them will easily be apprehended from the single intermediate one, ss, here shown. The iron wedges, ww w, of the rack-piece pushed downwards between.the yielding iron blades of the commutator are shown by black dots, forming a circuit in the usual manner for obtaining a reading of difference of temperature between the junctions aa',bb'. Kach loop or half-turn (4 fa, b'f'a') of iron wire is continued past ON THE THERMAL CONDUCTIVITIES OF CERTAIN ROCKS, 23 the upper junctions (a, a’) and carried through the, bath to a separate tooth of the commutator; and by moving the wedges of the rack-piece together one tooth-space to the right or left (as shown in new positions by a x in the figure), combinations of junctions in the bath with junctions (@a’) above or (bb') below the rock-plate are put into connexion with the galvanometer. By the same mode of trial as before, a heated iron plate coated with thin paper being substituted in the place of an experimental plate, the tempe- ratures of its two faces, as exhibited by the thermometer in the bath when the commutator was shifted from one of its two supplementary positions to the other, were sensibly the same as the heated plate slowly cooled, and no false difference of temperature arising from false currents differently excited in the two circuits thus joined up were found to be indicated as a result of several such determinations of the really equal temperatures of the two faces of the plate. This mode of observing the actual temperatures and the temperature-differences of the rock-faces in the present series of experiments was therefore constantly employed, and the values of the scale-divisions in degrees for the other more usual method of employing the thermopile were “not determined with special care, although this adjustment of the commutator was also used to check and follow the gradual variations of temperature- difference that were less speedily, although more certainly, measured by the absolute method of determination. The only case of failure to observe a sensible difference of temperature between the two sides of an experimental plate occurred with iron-pyrites, which (as well as galena), being a good conductor of electricity, it was found necessary to coat with two thicknesses of the thinnest tissue-paper on each face; and the apparent difference of temperature recorded (which was decidedly less than 1°) may have arisen from the resistance offered by the slight obstructions of these thin paper sheets (soaked with water) to the passage of the heat : although certainly very great, no definite value of the thermal conductivity of ordinary iron-pyrites can therefore be assigned. It was also necessary to use oil junctions instead of wet bladders, from the galvanic effects produced by the saturated salt solution, when rock-salt was tested; and it appears probable from some measurements of quartz with the same kind of luting that the conductivity of rock-salt thus found is somewhat less than, rather than likely to be in excess of, the real thermal conductivity of that substance. As a good assurance that when membranes wetted with water were used to press the thermopile against the rocks the true temperatures of their faces were very nearly marked, the experiment with iron-pyrites may be instanced, as the small temperature-difference of less than 1° could not have been observed if the wires were not very nearly indeed at the same temperature as the two paper- covered faces of the pyrites against which they were pressed; and as the circumstances of their adjustment in other cases were exactly the same as in this instance, it may be assumed that the method of pressing the thermopile against the rocks with wet bladders adopted in the present series of experi- ments exhibited the true temperature-difference of the faces, and afforded correct values of the thermal conductivities. The pressure was applied by means of strong spiral springs (instead of the weights described in the last Report), whose extensions in a graduated tube indicated the pressures which they were made to exert. The pressure thus applied was usually 80 lbs. upon a surface of nearly 20 square inches of the rock-plates, or about 4 lbs. . per square inch. The general agreement of the results with those formerly obtained also serves to verify the correctness both of the thermal conduc- tivities now assigned and of those previously cbserved. The principal differences in the two methods of determination consist in the use of an im- Rock specimen tested, 1876. (Water-satura- tion 7 vacuo.) Rock-salt (observed)...... Do. allowing for radiation Fluorspar Opaque white quartz...... Do. a new specimen Galena (interspersed with a little quartz). Pennant sandstone (near Bristol), thoroughly wet. LD oR Sif Rees CREE One Hard grit (Lee Abbey quarry, Linton, N. De- yon), thoroughly wet. Do. moistened by Ist ex- periment. Festiniog slate (specimen A, cut across the cleay- age). Festiniog slate (specimen A, cut parallel to the cleavage). Calcite (soft crystalline vein-stuff in red sand- stone, Clifton). Trap-rock, Pokham quar- ry, near Hxeter. Firebrick (fine ground Neweastle, thoroughly wet). Do. moist by Ist experi- ment. Cornish elyan (Christow Lead-mines, near Hxe- ter). Clay-slate from same lo- cality cut across the cleavage. Do. a specimen cut paral- lel to the cleayage. Another do, do............. English plate-glass ...... Heavy spar, opaque crys- tallized (Christow, Exe- ter): two experiments. Pumicestone thoroughly wet. Do. dry (or moist by Ist experiment). Newcastle house-coal...... REPORT—1876. Grains and per cent. (on rock- weight) of water absorbed. 308 grns. =6°3 per cent. 98 grns.= 1°75 per ct. see eerees seeeecece 432 grms.= 86 per ct. sete eeeee | 000738 Absolute conducti- vity observed. Wet- bladder junction. Luting of Oil and Red-lead. 001154 001180 0:00753 Bi { about | 0:00850 000705 0-00608 000550 0:00607 ee eeee 0:00565 0:00542 000315 000467 060868 0003849 000174 0:00294 0:00285 0:00268 0:00262 0-00186 to 000169 0:00103 0:00055 0:00057 proved thermopile, and in the substitution of wet membranes for the pre- viously employed moist luting of wet linseed-meal in the present series. Resis- tance. 87 88 108 to 133 135 142 Absolute about 117 164 \ es Absolute Conducti- vity (1875). \ 000880 0-00594 0-00549 0:00660 0:00325 0-00462 to 0-00488 | 000882 | 0-00866 000247 000147 00863 00325 00234 0-00065 Comparisons with former observations, 1875. Rock-specimen tested (1875). The same specimen. Kenton sandstone, thoroughly wet (5-7 per cent.). Do. dry (or moist by Ist experi- ment). The same speci- men. ; The same speci- men. Various marbles. Calton Hill Trap- rock. Whinstone. Fine red _ brick thoroughly wet (15°6 per cent.). Do. dry (or moist by Ist experi- ment). Welsh slates cut parallel to the cleavage. English alabaster (or gypsum). Cannel-coal. Where considerable discrepancies still exist, the discordance is rather to be ON THE THERMAL CONDUCTIVITIES OF CERTAIN ROCKS, 25 ascribed to the numberless small precautions required to ensure perfect accuracy, than to any constant errors of the methods with which either of the two series of determinations is now believed to be affected. In concluding this description, some remarks on the results of the new experiments that have been carried out will serve to show what new data have been obtained, and how far the observations made last year are corro- borated and confirmed by the slightly modified apparatus and method of procedure that has been adopted to extend the series. Among the points of principal importance noticed last year the following facts of great interest already ascertained have now been verified and con- firmed. Quartz is still found to have about the same high thermal conduc- tivity (85-88 concisely expressed, as explained at the beginning of this Report) compared to the other rocks which had been previously observed. The direction in which heat is transmitted through slate is a very important condition in regard to its conducting-power—the conductivity of good Welsh (Festiniog) slate cut across the cleavage being, however, to that of a plate of the same stone cut parallel to the cleavage-planes, as 5:3 from this year’s experiments, instead of 6:3 very nearly, as observed in the same slate specimens last year. The notable part of this difference of the two years’ observations is in the better-conducting cross-cut plate (54 instead of 66), although the other less-conducting plate (31°5 and 32:5) has nearly the same conductivity as it appeared to have last year. Cleavage-fractures which the cross-cut plate has suffered, and their repairs, rendering its surfaces uneven and the water-junction contacts consequently somewhat imperfect, have probably caused this apparent loss of conductivity in the transversely cut specimen of slate. But this latter still exhibits a much higher thermal con- ductivity than that shown by the plate from the same piece of slate cut parallel to its cleavage-planes. A less distinct difference was found this year in similarly sawn and tested plates of clay-slate cut across and parallel to the planes of cleavage or of foliation; but the stronger kinds of the stone which supplied a transverse section (as well as the less fragile plates cut parallel to the planes of cleavage) presented the appearance of cleavage and foliation only very imperfectly, and much less remarkably than the specimens of ordinary slate from Wales. The thermal conductivity of the soft clay-, slate is also less in all directions (26-28-5) than the least observed conduc- tivity (31-5) of Welsh slate cut parallel to its cleavage-planes. The observations of the effect of moisture in increasing the conductivity of the porous rocks, when thoroughly saturated with water, entirely corro- borate the similar observations made last year. When the great pressure required. to force a sensible quantity of water through such rocks as sandstone and others which were tested is compared with the very feeble currents which differences of temperature and of density of the water in their cavities can produce, it appears evident that the very marked increase of conductivity observed in such cases cannot be owing to convection- or gravitation- currents in the water which the saturated rocks contain, although the mobility of the liquid by diffusion and consequent intermixture of its mole- cules probably assists the direct conducting-power of water in the transmission of the heat ; and the resulting conductivity of water, free from the action of conyection-currents, appears to be at least equal to that of some rock-species whose thermal conductivities are either the last or nearly the lowest in the present list. The thermal conductivities of certain new species of rocks are now also assigned, the values of which, although they are few in number, appear to possess considerable interest from a mineralogical as well as from a geological 26 REPORT—1876. aspect. Some crystalline rocks and minerals of simple composition (and of the cubic system of crystallization) were selected, and, like quartz, they proved to have heat-conducting properties in a high degree. The thermal con- ductivity of iron-pyrites, resembling apparently that of the metals, could not, from its high value, be accurately determined by the method of experiment pursued ; and it is accordingly omitted (as undetermined) from the list. The diathermancy of rock-salt for the heat radiated and absorbed by the oiled surfaces between which the trial plate of it was placed will not account for more than J, part of the heat which the plate actually transmitted; and the high position of this substance in the list is consequently due to a really high conductivity which rock-salt possesses (about 113), greater than that of quartz (85-88), and even of fluorspar (923), the substance found to rank next to it in high conducting-power. A specimen of galena nearly pure, but enclosing a few fragments of quartz, presented the highest thermal conduc- tivity (704) next to that of quartz. A plate of soft, white, opaque calcite, perfectly but irregularly crystallized (forming vein-stuff in Clifton sandstone), agrees exactly in its thermal conductivity (46°7) with various kinds of marble (46-49) which were tried last year. On the other hand, a similar specimen of heavy spar (barium sulphate) from a mine of that substance near Exeter presents, in spite of its great density, a remarkably low thermal conductivity (17-18 in two experiments), not very far removed from that of Inglish alabaster (gypsum, or calcium sulphate, 23-4). English plate-glass (20-4), it may also be remarked, has a low thermal conductivity, differing not very greatly from those of the two substances last named. Finally, the lightest species of rocks examined in the course of these experiments, pumicestone and Neweastle house-coal, have also the lowest conductivities (5°5 and 5:7) hitherto presenting themselves in these investigations. As, with the exception of rock-salt, clay-slate and elvan, house-coal and pumicestone, no new thermal resistances of great importance, in a geological point of view, are added in the present list to those already exhibited in the diagram of these Reports (vol. for 1875, p. 59), a new graphic representation of the resistances now found is here deemed unnecessary—the values of the absolute resistances furnished in this Table enabling them to be added without ‘difficulty in that diagram, where they may thus be exhibited in the same normal scale with the earlier determinations. The applications to questions of underground temperatures which these observations suggest have not yet engaged the Committee’s attention suffi- ciently to enable them to arrive at definite conclusions certain enough to ~ entitle them to be noticed in this Report. Examples of very reliable mea- surements of underground temperatures, such as have recently been obtained in the tunnels of Mont Cenis and of St. Gothard, and in the deep vertical boring at Sperenberg, near Berlin (the last of which, although extremely deep, passes almost entirely through rock-salt), are ill-adapted to test distinctly the relative values of the thermal conductivities of different species of rocks— the former two from the irregular surface-configurations, and the last from the absence of any change of the strata through which these borings pass. In view also of the many disturbing conditions that affect both the lecal rate of change and the actual observations and measurements of underground temperatures in other borings more suitably adapted to exhibit clearly the differences of thermal resistance in geological formations, which the Com- mittee is endeavouring to distinguish and to recognize in actual cases, it would be premature, in the present stage of the investigation, to deal more particularly with results derived immediately from these and from similar comparisons, the degree of dependence to be placed on which cannot very ON THE ASSESSMENT OF DIRECT TAXATION. Pi, easily be defined. The agreement which they trust eventually to trace between the observed temperatures and the experimentally determined thermal properties of the locally predominating rocks is liable to be masked and concealed by causes of disturbance of so many unknown and unsuspected kinds, that plain and obvious corroborations are not frequently to be expected ; and the nature of those causes which principally tend to disturb the results will probably become better known by the progress of further comparisons such as the Committee is now endeavouring to pursue. While it was thus anticipated by Prof. Everett*, from the slow rate of temperature-variation from the surface observed in the rocky excavations of the Mont-Cenis tunnel, that quartz (which is a principal ingredient of the rock) would prove to have a high thermal conductivity, this property is now also found to belong to rock-salt, through which the Sperenberg boring passes with an average rate of temperature-variation (1° F. in 51 English feet) scarcely differing sensibly from the mean rate obtained from a mass of similar observations taken in other places and recorded by the Underground Temperature Committee. The apparent contradiction presented by these two cases may possibly proceed from a more rapid local rate of variation of temperature in the neighbourhood of Sperenberg than around Mont Cenis; and the fact that in the first 60 fathoms of ordinary strata overlying the rock-salt the observed rate of variation was slower than below (contrary to what would be expected from the relative conductivities of the superincumbent strata and the underlying masses of rock-salt), is said, in Herr Dunker’s description of the obser- vations, to be probably accounted for by the intrusion into the boring near its mouth of the waste warm water of the engines on the surface. The effect, it may be observed, of a highly conducting mass, like that of the deep bed of rock-salt here penetrated, by diminishing the local resistance and increasing the flow of internal heat outwards through the Sperenberg strata, would be to cause the local rate of variation of temperature in this locality to be abnormally rapid; and perhaps this may explain why a slow rate of variation is not observed in this instance, from the great depth of the ex- cellently conducting rock-salt formation, which considerably exceeds 3000 feet. The Sperenberg boring thus presents examples of secondary conditions which will perhaps prove to be in good agreement (instead of, as they at first appear to be, somewhat at variance) with the results of the Committee’s observations. Report of a Committee, consisting of the Right Hon. J.G. Huszarp, M.P., Mr. Cuavwick, M.P., Mr. Moruny, M.P., Dr. Farr, Mr. Hatiertr, Professor Jevons, Mr. Newmarcu, Professor Lronr Levi, Mr. Hexwoop, and Mr. SuaEn (with power to add to their number), appointed for the purpose of considering and reporting on the practicability of adopting a Common Measure of Value in the Assessment of Direct Taxation, local and imperial. By Mr. Hatuerr, Secretary. Your Committee, appointed to inquire into the subject of a Common Measure of Value in Direct Taxation, have proceeded in this inquiry, have considered the matters to them referred, and have agreed to the following Report :— * See these Reports, vol. for 1875, p. 16, note at bottom of the page. - 28 REPORT— 1876. 1. Measure of value wanted.—The question of a common measure of value is one of a class that may be literally called standard questions, and its solution is at the basis of equality in taxation both general and particular. Values are the object matters of taxation, their measurement and comparison are the necessary condition of its equal incidence; and measurements with unequal measures are like weighings with unjust balances. Taxation, how- ever pure its intention, without a common measure of value, is what navigation would be without sextant and chronometer, or architecture without compass and level. And this perhaps is not an unfair description of what it actually is, though not, it may be hoped, of what it must be. One of the chief marks of advancing science has been a progress towards better measures and better measurements, a substitution of the uniformities of rules of reason for the unrestricted vagaries of rules of thumb; and such is the aim of the present inquiry. This question of a common measure of value is the question of the common measure of taxation; or if there be several such measures, what is their common ratio? what are they in terms of one another? 2. Two Methods of General Valuation: Capital-Value and Usable Value-— Measurements of the value of things (employing this word “things” as inclusive of land, labour, stock, &c.) may have reference to their absolute worth or to their temporary uses. They may have reference to their pro- perty, capital, or absolute values, or to their products, profits, or annual values. The one measure is exemplified in contracts of sale and purchase, the other in contracts of letting and hiring. Each has its special advantages and special applications. Capital or absolute value is applied in the assess- ment of probate and legacy duty; usable value in the assessment of local taxation and in those of the imperial income-tax. Moreover, as the capital- value of the thing must be equivalent to the present value of the sum of its future uses, the two measures, if consistently defined, though differing it may be year by year, must be in the long run equivalent. But such consistency of definition is an essential. The idea of capital-value is tolerably well fixed, but that of usable or lettable value is indefinite. Usable value is, or is equivalent to, the consideration paid for, the income received from, the use of things. This consideration, however, may be paid under such totally different conditions of contract that, unless these conditions are first assimi- lated, the payments regarded as measures, either of the values of the things or of the abilities of their owners, are worse than useless: they are mis- leading. 3. Usable Value unrestricted and indeterminate and hence unfit as a com- mon measure.—To illustrate this: things having a use, and hence capable of becoming sources of income, are all, by the very nature of the process, liable to outgoings ; some more, some less. Production involves productive con- sumption. Efficiency implies cost—cost, for the most part of insurance against natural risk ; of repairs; of necessary depreciation. But the user of a thing, be it land, labour, or stock, may engage for its use with or without liability to these outgoings; their costs may be borne by the user or by the owner, or they may be divided between the two in any proportion that con- venience may direct. The user may bear repairs and the owner natural risk and depreciation, or the user may bear natural risk and repairs and the owner natural depreciation, or the user may bear all and the owner none, or the user none and the owner all, the consideration given (the income received) of course varying accordingly. Were the things valued by absolute sale or capitalization, all the incidents, whether of efficiency or cost, plus or minus, would be wholly and uniformly included, and the test would fix the things’ relative positions. In valuation by uses, however, it is evident that these ON THE ASSESSMENT OF DIRECT TAXATION. 29 incidents are not as a matter of practice uniformly included, and the valuation, founded upon unfixed conditions, can fix nothing ; its possibilities of variation are coextensive with those of free contract itself, and hence, being absolutely unrestricted, as a measure it must be inherently unfit. 4. Exemplified in incomes of Income-tav.—Such valuations, some tempering effect of deductions notwithstanding, have been those of local taxation ; and hence the local chaos which Mr. Sclater-Booth’s bill was the last attempt to reduce to order. Such also, without any tempering influence, are the valuations of income under the present income-tax. In this latter the returnable and taxable incomes of interest, land-rent, house-rent, royalties, wages, including professional fees and salaries, are the considerations that are paid for the uses of principal monies, land, houses, mines, and labour respectively. Interest, however, is the consideration paid for the use of the principal, neither user nor owner being subject to any outgoings. Land-rent is the consideration paid for the use of land, the user bearing almost all outgoings. House-rent is the consideration paid for the use of houses, the owner and user sharing the outgoings in various proportions. The owner also largely bears outgoings in the contract of mines and royalties ; he wholly bears them, as a rule, in that of labour and wages. Moreover these out- goings vary according to the nature of the thing; they may vary from zero up to 40 or 50 per cent., or even more, of the gross production. It is these differences that give rise to the various characteristics of incomes, as gross, net, certain, precarious, terminable, permanent, nominal, real. All, indeed, are in the catalogue of considerations paid; all are so-called incomes received, but only “As hounds and greyhounds, mongrels, spaniels, curs, Shoughs, a ag and demi-wolves are cleped All by the name of dogs.” The true account “ distinguishes” we are told, and gives to each “ particular addition:” the measure of incomes, too, that lays claim to scientific truth must do the same, and to the “ bill that writes them all alike” and taxes them all alike, must add natural differences and just discrimination. 5. Usable value specialized and determined as Interest-value. By consis- tent deduction of outgoings. Interest-value as the common measure required.— And if the cause of these inequalities of valuation be rightly stated, the dis- covery of such measure ought not to be difficult. As the inequalities arise from the different conditions in respect to outgoings under which the various incomes are calculated, the remedy must be the assimilation of these condi- tions ; and the case of principal and interest, which in one aspect may be regarded as a common expression of sources and uses generally, may be employed as a precedent. Interest, as before said, is the income received from a thing free of outgoings. It leaves the thing or its capital value unimpaired. The extension of this idea to revenues or incomes in general is simply the universal deduction from them of their productive outgoings— equivalent to the general restoration of the capital-values of their respective sources. Under such a regime, returnable and taxable income would not be land-rent, house-rent, mine-royalties, labour-wages; but land-rent minus land-outgoings, house-rent minus house-outgoings, mine-royalties minus mine-outgoings, labour-wages minus labour-outgoings ; and similarly with terminable annuities and the profits of business, the outgoings, however, being in all cases only the necessary ones of the production. The result thus obtained would be what by analogy we may call the interest-value of the various sources; and such interest-value of land, of labour, of houses, of 30 REPORT—1876. economic agencies generally, would be the common measure required. And the measure is a perfectly scientific one, and, indeed, admits of mathematical expression. As the exact difference, comprehensively considered, between the total receipts and total outgoings of a source, it is the pure annual increment of its capital-value, and hence is identical with absolute profit. It would represent the pure annual growth of national wealth taken in its widest sense, and the returnable income of national taxation. 6. Precedents for its practicability.—But .are such deductions of outgoings on the sources of income and the determination of the interest-value practi- cable? In many cases this question has been already solved by actual legislation. ‘That such deductions are practicable for lands, houses, and mines may be proved by reference to the Metropolis Valuation Act of 1869, and to the Local Valuation Bill before referred to, both of which are grounded on them, and have schedules of deduction for different cases attached. That they are practicable for machines, ships, trade fixtures, horses, and stock generally, the Income-tax Act, with its special clauses for repairs and re- supply, itself recognizes ; and though no schedules or deductions are attached for these cases, the deductions are well known in the estimates of business and recognized in the Surveyor’s office. But if such deductions of outgoings are practicable for the labour of horses, are they not practicable for the labour of men? Economically considered, the two labours are analogous; both are productive agents, both have productive powers subject to consumption. Natural risk, maintenance, and terminability belong to the labour of men just as they belong to the labour of horses, just as risk, repairs, and termina- bility belong to machines, ships, or implements. All these outgoings are facts equally ascertained by experience, and it is difficult to see why their valuations are not equally practicable. They are as much an item ina source’s general account as the receipts themselves, forming its debit as these form its credit column. Nor can any account, be it individual or national, be said to be complete unless both sides are considered. 7. Effect on Income-taw Act.—The application of this interest-value measure to the Income-tax Act would give these results :—Incomes from lands, houses, and mines would be charged much the same as under the proposed new local valuation system. Dividends and profits of capital, purely considered, would be charged as at present. Government and other terminable annuities would not be taxed on the amount representing the restoration of capital. On the same principle the incomes from labour, whether pure, as in the case of salaried officers and some professors, or mixed with the proceeds of capital, as in other professions and as in businesses, would be entitled to material deductions varying with the relative proportions of skill and capital engaged. In all cases the tax would be collected at the source and levied on the net value of the produce ; and the deductions would be made without reference, as such, either to the position or fortune of the owner. 8. Practicability exemplified in composite incomes.— Questions may be raised on the practicability of applyimg an outgoings deduction to incomes from businesses and professions which are the mixed results of labour and capital. It may be objected either, first, that as labour and capital enter into these mixed incomes in varying proportions, and as the percentage of labour- outgoings is very different from that of capital-outgoings, a deduction common to these mixed incomes and to unmixed labour-incomes would be unjust ; or, secondly, that if the labour-income and capital-income be assessed separately a separate return of capital will be necessary, and that this must entail an objectionable exposure of affairs. ‘l'o meet the first objection, a classification ON THE ASSESSMENT OF DIRECT TAXATION, 81 of business and professional incomes, with a varying percentage deduction according to the average proportion of capital in each class, has been pro- posed; but it may be doubted if the second objection has any just foundation. That the assessment of an income from conjoint sources does not necessarily involve an official return of these sources, may be seen by looking to the return of the income of capital or stock itself, as exemplified in all large trading companies. This income, regarded in the concrete, consists of the conjoint incomes from houses, ships, machinery, stock, trade fixtures, all of which incomes having different outgoings, are singly and differently assessed by the owner, but all of which are united, without statement of particulars, in one common official return. What is practicable, however, with the incomes (derived, say, from horse labour plus machinery) is also practicable with those derived from human labour plus capital generally. Doubtless, in order to value the labour-income separately from the capital-income, the two must be separately known to the yaluer, but not, therefore, separately returned to the Government unless Government undertakes the work of accountant. ‘The distinction between the two (the one technically known as profits, the other as interest) is a primary distinction in book-keeping usually given in eyery profit and loss account. Capital being{known (and this knowledge is as necessary to the preparation of an accurate return under the present system as to that under the proposed one), its interest subtracted from the mixed income will give the technical profits, gross labour-income, or gross wages of the capitalist. The deduction of labour-outgoings from the labour-income will give the labour’s interest-value, which, plus the interest of the capital, will be the interest-value or returnable income of’ the business or profession. Example 1.—A (a barrister, physician, or salaried officer) has £1000 a year, an unmixed gross labour-income. Assuming, ¢.g., 40 per cent. to be the average labour-outgoings for risk, maintenance, and “ depreciation,” the deduction will be £400 and the interest-value £600. A’s returnable and taxakle income will be £600. Example 2.—B (a solicitor or general medical practitioner) has £2000 capital in his practice, and a gross income as now returnable of £1000 a year, the joint result of his personal labour and his capital. Interest being reckoned at 5 per cent., £100 will be the interest-value of his capital, and £900 the gross income, wages, or so-called profits of his labour. - The deduction of 40 per cent. from this for labour-outgoings leaves £540 as the labour’s interest-value, which, plus £100 as the interest of capital, gives £640 as the interest-value of his practice. B’s returnable and taxable income will be thus £640. Example 3.—C (a merchant, manufacturer, or shopkeeper), having a capital of £10,000 in his business, has a gross income of £1000 a year, the joint result of his capital and personal labour. Here, under the former suppositions, the interest of his capital will be £500, and the gross income of his labour will be £500. Deducting 40 per cent. for labour- outgoings, as before, we obtain £300 as the labour’s interest-value, which, plus the interest of the capital, equals £800, the interest-value of the business. C’s returnable and taxable income will be £800. Zero-point of Direct Taxation——In the remuneration of labour, as we descend in the scale, there must be a point at which income and outgoings balance, and at which, therefore, interest-value or real profit is zero. This Important point in labour, analogous in land to the commencing point of oz REPORT—1876. rent, is the scientific division in labour between exemption and taxation that a common measure of value determines. Wherever the point may be, below it there is no interest-valne, and hence ought to be no taxation; and it is above this point that in strictness the percentage deduction for outgoings ought in every case to begin. Example 1.—A, a labourer, earns 30s. per week, an unmixed gross labour- income. Assuming this sum to be-only sufficient to meet the necessary labour-outgoings, then the interest-value of the income will be nil. A’s income will be wholly untaxable. Example 2.—B, a clerk or artisan, earns £150 per year. Assuming, as before, 30s. per week or £78 per year, as the necessary labour-outgoings, then the subtraction of this sum will mark the zero-point of the labour’s taxable income, and £72 will be the margin to which alone the per- centage deduction for outgoings ought to be applied. Assuming this deduction at 40 per cent. as before, we have £22 as such deduction, and £44 as the labour’s interest-value. B’s returnable and taxable income will be £44. A similar preliminary process of correction applies to all higher labour- incomes, the zero-point being determined by the amount fixed on as the labour’s necessary outgoings. 9: Proposed new Valuation System intermediate to the Self-assessment and Official Systems.—The practical working of a measure of value, like other measures, has necessarily a relation to the persons by whom it is applied. A just measure, through careless or wrong application, may act unjustly ; but unjust application is no argument for an unjust measure; an unjust measure even when rightly applied must act unjustly. In the income-tax, as now arranged, with its five or six inconsistent measures of value, the valuation for some of the chief schedules ranges between the loose liberties of self- assessment and the inquisitorial stringency of official: the one system con- scious of a radical injustice in the law, which it is itself called on to apply, the other in total ignorance of the facts which the law covers, and both working in antagonism to each other. In the valuation for probate duty we have a third system, applied not by the interested individual nor by the official, but by a third and independent party, authoritatively licensed, indeed, by the Government, but selected by the individual, and hence whilst neutral himself, haying responsibilities to each. Under an equitable measure of value, self-assessment might in the first instance exist as at present; but in cases of doubt Government might require the guarantee of such an independent authority (licensed valuer, accountant, lawyer, acting as a semiofiicial com- missioner in income-tax) for a second evidence to the truth of the return, reserving its own power of official examination as a last resort. At the present time many firms do actually call im professional accountants to make up their returns; and with a growing sense of justice in the tax, such an independent guarantee to the truth of the return might not improbably become general, and might even acquire the force of a custom. CoMPARISON BETWEEN CAPITAL-VALUE AND InrEREST- VALUE. 10. Capital-value and Interest-value equivalent on a series of years, but not for each year.—The two measures, capital-value and interest-value, are, as before observed, on a series of years equivalent. Interest-value is capital- value for a year. Capital-value is the present worth of interest-value for all ON THE ASSESSMENT OF DIRECT TAXATION, 33 years. But though the two measures are thus equivalent on an average of years, they are not equivalent for each specific year. Interest-value measures the gains of capital for one year, and capital-value measures its gains for that year, with the expectant or probable gain of future years added. As, however, national gain for any year has, as a rule, the closest relation to the national expenses for that year, the interest-value is a more specific measure for annual taxation than the capital-value; and this is probably the reason that has unconsciously led to the adoption of an annual-value measure, both eee and imperial taxation, in preference to one of capital or perpetual value. Capital-value in comparative relation to things and to tenwres generally.— Measures practically equivalent may, however, through differences of appli- cation, give contrary results ; and of this the two measures in question afford illustrations. Taxation, according to capital-value, may look either to the sources, things, or objects owned, or to the rights and tenures of their owners—to the land, labour, or stock possessed, or to the freehold, leasehold, life-tenancy, or jointure, as the case may be, of the possessors. Prima facie it would appear that as the value of the tenures of a thing, however manifold, can be neither more nor less than the value of the thing itself, the results of the scientific capitalization of the two should be identical. As a matter of fact, however, this has not been admitted to be the case; and itis on the question of tenures that the deepest controversies of the income-tax have arisen. Capital-value in relation to terminable tenwres.—As the capital-value of a limited tenure in an estate, for example, is less than that of a permanent one, its taxation, it is argued, ought to be less, and therefore it ought to pay at a lower rate. Putting aside for a moment the question of the truth of this inference, it is evident that its enforcement would make an estate’s taxation ‘vary with the character of its tenure, thus giving power to the subject to alter taxation by altering tenure, and that to almost any extent. To avoid this it has been proposed to derive the whole tax from the estate as at present, but to levy on the limited tenure according to its capital-value, and to make the reversion liable for the balance. Terminability of tenure does not influence the Annual Tax.—Without dis- cussing the administrative difficulties of this view, it may be questioncd whether such a view be a logical deduction from the principle of taxing tenures according to their capital-value. Assuming that a limited tenure in an estate ought to pay less than a permanent one, with reference to its capitalized value, it would not therefore follow that it ought to pay at a lower annual rate. Be the tenure long or short, the estate for any given year is the same, the value for that one year’s tenure is the same, the government protection afforded to it for that year is the same, and hence it would appear that the payment for each year ought to be the same also. But if each year’s payments be the same in both cases, the total payments are not therefore equal; the limited tenure pays only for a limited time, whilst the perpetual tenure pays for all time; and if these payments be aggregated it will be found that their amounts are in exact proportion to the capital-yalues of the respective tenures. Should it be said that the reyersioner, haying interests in the good government of the present, ought therefore to contribute according to the value of these interests, the reply is that the present possessor has been ihe reversioner of the past, and has had similar interests in the good govern- ment of the past. If, therefore, present possession has a claim on the future, it owes a debt to the past; and it may be mathematically shown, what 1876, D 34 REPORT—1876. perhaps a sense of the fitness of things indicates, that for any given year the claim and debt will cancel each other, and leave every year’s possession to ‘pay the whole year’s tax on the estate possessed. Difference between incomes from terminable tenures and those from termi- nable things.—That a terminable income by paying at the same annual rate as a perpetual income is equally paying according to its capital-value, is a pro- position insisted on by Mr. Warburton and by Mr. Mill in the two Commissions on the Income-tax; and as far as the above class of terminable income is concerned, the proposition is true. But these gentlemen unfortunately carried it into a region where it had no status, and in virtue of it denied the applicability of capital-value, if not of arithmetical proportion generally, as a reforming measure of the income-tax. As there are incomes and incomes, so there are terminable incomes and terminable incomes. If the terminable income be the terminable tenure of a pure interest-value, such, practically speaking, as a life-interest in land or in consols, to tax it at the same rate as a permanent income is to tax each according to its capital-value. It, however, the terminable income be an income that is made up partly of interest-value and partly of capital that terminates, not simply as a legal right, but by gradually exhausting its source, then to charge such income at the same annual rate as a permanent one of similar amount is not to tax it according to its capital-value—a truth repeatedly demonstrated by the actuaries before Mr. Hume’s committee, and evident from the reflection that the capital-value of the source is, by the very nature of the income, continu- ally passing away, whilst the tax remains the same. Under the conditions stated, the tax on the one terminable income would be a tax on pure interest-value, the tax on the other would be a tax on a mixture of interest- value plus capital. By combining the propositions of the actuaries and of Mr. Warburton, each true in its own sphere, but each erroneous when applied to the other, we may conclude that the results obtained from the capitalization of tenures are identical with those obtained from the absolute valuation of sources; and both may be quoted in confirmation of those obtained from the principle of interest-value. Capital-value in relation to personal riches and property. Common measure of value as needful for equal exemption as for equal taxation.—Another appli- cation of capital-value as a measure, however, cannot be so quoted. The taxation of a particular property according to capital-value may be inter- preted as taxation, not according to the worth of that particular property, but according to the absolute worth or financial position of the person who owns it; and such a method of levy has been erroneously defended as taxation according to ability. In this view a rich man ought (considerations of practicability apart) to pay a heavier duty upon his dog, his bottle of wine or whiskey, than a poor man; and, the estates being equal, the owner of a permanent tenure would pay more for each year’s possession than would the owner of a limited one. Such a theory of capital-value may not be general, but it has a certain degree of popularity, and seems to be constantly getting itself mixed up not only with discussions but even with legislation on the incidence of the income-tax. It may be questioned whether the operation of this theory is not visible, for example, in the exemption from imperial direct taxation (recently so largely extended) of large masses of property in the country including many thousands of acres of land, in consequence of the ‘accident of their ownership. Property thus exempted becomes property taxable by mere change of possession, irrespective of the intrinsic nature or value of the property itself. To exempt in an income-tax the necessary ‘ ON THE ASSESSMENT OF DIRECT TAXATION. 35 outgoings of the source of income, be it labour or land, is merely to confine the tax to its own stated objects, viz. to income proper; but to exempt or lower the rate on this income proper, merely in consideration of the personal status of its owner, is to travel into quite a different region—it may be into the region of national charity, or into that of some other principle, but assuredly far away from that of equality in taxation. It may be added that such exemptions, even when admitted, need a common measure of value for their rational application. There are small incomes and small incomes— incomes that are pure interest-values, incomes that are pure drafts on capital, and incomes that are mixtures of interest-value and draft on capital ; and the equal exemption of these kinds, as in the present income-tax, is as un- equal as would be their equal taxation. As before said, the interest-value measure itself would exempt all small labour-incomes to the extent of their necessities without further special rule. Bearines or Common Muasvre oF VALUE ON GENERAL TAXATION AND Narronan Income. 11. Common measure of value necessary to the adjustment of general tax- ation: fallacies from its absence.—“ Your Committee also feel that it would be unjust to make any alteration in the present incidence of the income-tax, without at the same time taking into consideration the pressure of other taxation upon thevarious interests of the country, some of it imposed by recent legislation, and in one case especially, that of the succession duty, to some extent by way of compensation.” This, written in 1861, is the last sentence of the Report of the Select Committee appointed in that year on the equa- lization of the Income-tax ; and perhaps no paragraph could be quoted as a stronger argument for the necessity of determining a common measure of value. It may, indeed, be thought by some that for the purpose of internally equalizing a tax over its own area, be that area sugar, coffee, or incomes, a preliminary inquiry into the pressure of taxation in general is somewhat of a work of supererogation ; and it may not be mathematically obvious to others what possible sort of compensation can exist between the inequalities of a tax, or a set of taxes, that are almost stationary, and those of one that changes with every national emergency—that in twenty years has actually compassed the extremes of sixteenpence and twopence in the pound, with every variety of intermediate oscillation. But assuming it to be advisable for the purpose in question, as it must doubtless be always generally useful, to know the comparative pressure of taxation as a whole upon the interests of the country, it is clear that such a knowledge implies their valuation through a common measure, and is, indeed, as impossible without it as would be the knowledge of the weights of different things without weighing them by a true balance. Eminent statists have, indeed, attacked this problem, using income itself as the means of the comparison, though oftentimes without a sufficient preliminary examination of the accuracy of their instrument. Comparing the statistics of different classes of income, as collected from the government returns and from inquiries specially made, with the statistics of the corresponding classes of taxation, they have sometimes concluded that general taxation is, as a whole, tolerably equal. The truth of this conclusion evidently depends upon the uniformity of the standard employed. As, however, this uniformity has no existence (the government returns alone presenting at least five or six different modes of estimate), the argument can prove nothing as regards general equality, except its.absence ; but does prove 2s taxation D2 36 . REPORT—1876. ‘ in general, regarded as a larger income-tax, is equally in want of a common measure with the income-tax proper. So far from the measurement of the income-tax proper being dependent on the measurement of general taxation, the measure that underlies them both is one and the same; and, indeed, the true view of an income-tax is that it should be a perfectly just and equal tax in itself, rather than an imperfect tax compensating the imperfections of other taxes. Conmon measure of value necessary for finding national income wnd wealth : fallacies from its absence.—The evil consequences of a want of a common measure of value, seen in the comparison of incomes for purposes of taxation, is also seen when they are added together for the exhibition of the amount of national income and wealth. To find this national income, the government returns of the income-tax have been taken, and to this miscellaneous aggre- gate the exempted incomes of the country, including manual-labour wages, ‘have been added, as if all were of one equal and uniform denomination. Much of such income, however, as has been repeatedly pointed out, is only the consumption of capital. Within the period of a generation, say thirty years, all the value of human labour, plus the cost of maintaining it, passes into the category of labour-income. Within longer but varying periods the value of all houses, plus the cost of repairing them, passes into the category of house-income. Within still more varying periods all the mining wealth of the country must pass into the category of mining-income and disappear ; and all capital of terminable annuities passes into terminable income. By some writers this medley of so-called income (but no more income than the payments for exports are income, or drafts on bankers are income) has ever been capitalized at one (and that an extreme) rate, to get the national wealth, the result of the whole process being an exaggerated and practically mis- chievous estimate of national income, of national wealth, and of the nation’s capacity to bear taxation. Probably no better example than this could be given of the necessity of a common measure of value. Common measures (common units) are the souls of statistics, as, indeed, they are of knowledge generally. Without them statistics are a mere incoherent mass of facts, usurping the semblance and function of exact science. A common measure of income, discovering the amount of the element common to rent, wages, profits, and interest, determines the true increment of wealth considered in its widest sense, and expresses both the extent and the ratio of economic progress. This common measure may be briefly described as interest-value ; it is an essential, if not the fundamental, basis of taxation, Report of the Committee, consisting of Professor Cirrk Maxwett, Professor J. D. Evernrr, and Dr. A. Scuusrer, for testing experi- mentally Ohi’s Law. Tne statement of Ohm’s law is that, fora conductor in a given state, the electromotive force is proportional to the current produced. The quotient of the numerical value of the electromotive force divided by the numerical value of the current is defined as the resistance of the con- ductor; and Ohm’s law asserts that the resistance, as thus defined, docs not vary with the strength of the current, ON OHM’S LAW. 37 The difficulty of testing this law arises from the fact that the current generates heat and alters the temperature of the conductor, so that it is ex- tremely difficult to ensure that the conductor is at the same temperature when currents of different strengths are passed through it. Since the resistance of a conductor is the same in whichever direction the current passes through it, the resistance, if it is not constant, must depend upon even powers of the intensity of the current through each element of the conductor. Hence if we can cause a current to pass in succession through two conductors of different sections, the deviations from Ohm’s law will be greater in the conductor of smaller section; and if the resistances of the conductors are equal for small currents, they will be no longer equal for large currents. The first method which occurred to the Committee was to prepare a set of five resistance-coils of such a kind that their resistance could be very accu- rately measured. Mr. Hockin, who has had great experience in measuring resistance, suggested 30 ohms as a convenient magnitude of the resistance to be measured. The five coils and two others to complete the bridge were therefore constructed, each of 30 ohms, by Messrs. Warden, Muirhead, and Clark, and it was found that a difference of one in four millions in the ratio of the resistance of two such coils could be detected. According to Ohm’s law, the resistance of a system consisting of four equal resistance-coils joined in two series of two should be equal to that of any one of the coils. The current in the single coil is, however, of double the intensity of that in any one of the four coils. Hence if Ohm’s law is not true, and if the five coils when compared in pairs with the same current are found to have equal resistances, the resistance of the four coils combined would no longer be equal to that of a single coil. A system of mercury-cups was arranged so that when the system of five coils was placed with its electrodes in the cups, any one of the coils might be compared with the other four combined two and two. After this comparison had been made, the system of five coils was moyed forward a fifth of a revolu- tion, so as to compare the second coil with a combination of the other four, and so on. The experiments were conducted in the Cavendish Laboratory by Mr. G. Chrystal, B.A., Fellow of Corpus Christi College, who has prepared a report on the experiments and their results. A very small apparent deviation from Ohm’s law was observed ; but as this result was not confirmed by the much more searching method of experiment afterwards adopted, it must be regarded as the result of some irregularity in the conducting-power of the connexions, The defect of this method of experiment is that it is impossible to pass a eurrent of great intensity through a conductor without heating it so rapidly that there is no time to make an observation before its resistance has been considerably increased by the rise of temperature. A second method was therefore adopted, in which the resistances were com- pared by means of strong and weak currents, which were passed alternately through the wires many times in a second. The resistances to be compared were those of a very fine and short wire enclosed in a glass tube, and a long thick wire of nearly the same resistance. When the same current was passed through both wires, its intensity was many times greater in the thin wire than in the thick wire, so that the deviation, if any, from Ohm’s law would be much greater in the thin wire than in the thick one. Hence, if these two wires are combined with two equal large resistances in 38 REPORT—1876. Wheatstone’s bridge, the condition of equilibrium for the galvanometer will be different for weak currents and for strong ones. But since a strong current heats the fine wire much more than the thick wire, the law of Ohm could not be tested by any ordinary observation, first with a weak current and then with a strong one, for before the galvanometer could give an indication the thin wire would be heated to an unknown extent. In the experiment, therefore, the weak and the strong current were made to alternate 30 and sometimes 60 times in a second, so that the temperature of the wire could not sensibly alter during the interval between one current and the next. If the galyanometer was observed to be in equilibrium, then, if Ohm’s law is true, this must be because no current passes through the galyanometer, derived either from the strong current or the weak one. But if Ohm’s law is not true, the apparent equilibrium of the galyanometer-needle must arise from a succession of alternate currents through its coil, these being in one direction when the strong current is flowing, and in the opposite direction when the weak current is flowing. To ascertain whether this is the case, we have only to reverse the direction of the weak current. This will cause the alternate currents through the gal- vanometer-coil to flow both in the same direction, and the galvanometer will be deflected if Ohm’s law-is not true. Mr. Chrystal has drawn up a report of this second experiment, giving an account of the mode in which the various difficulties were surmounted. Currents were employed which were sometimes so powerful as to heat the fine wire to redness ; but though the difficulty of obtaining a steady action of the apparatus was much greater with these intense currents, no evidence of a deviation from Ohm’s law was obtained ; for in every experiment in which the action was steady, the reversal of the weaker current gave no result. The methods of estimating the absolute values of the currents are described in the Report. A third form of experiment, in which an induction-coil was employed, is also described ; but though this experiment led to some very interesting re- sults, the second experiment gives the most searching test of the accuracy of Ohm’s law. Mr. Chrystal has put his result in the following form. If a conductor of iron, platinum, or German silver of one square centimetre in section has a resistance of one ohm for infinitely small currents, its re- sistance when acted on by an electromotive force of one volt (provided its temperature is kept the same) is not altered by so much as ae part. It is seldom, if ever, that so searching a test has been applied to a law which was originally established by experiment, and which must still be considered a purely empirical law, as it has not hitherto been deduced from the funda- mental principles of dynamics. But the mode in which it has borne this test not only warrants our entire reliance on its accuracy within the limit of ordinary experimental work, but encourages us to believe that the simplicity of an empirical law may be an argument for its exactness, even when we are not able to show that the law is a consequence of elementary dynamical principles. First Experiment. Christmas 1875. By G. Curysrat, Cavendish Laboratory, Cambridge. Communicated by J. Crmrk Maxwett. If the electromotive force between two points of a uniform linear con- ductor measured in appropriate units by means of an electrometer be E, and ON OHM’S LAW. 39 the quantity of electricity that passes through any section of the conductor in unit time, measured either by a galvanometer or by a voltameter, be Cythen, according to Ohm’s law oP is directly proportional to the length of the con- ductor, and inversely proportional to the area of its section. "The coefficient of proportionality for a definite substance depends merely on the temperature of the substance; for unit length and unit section of a given substance the value of the ratio a for a given temperature is called tho specific resistance of the substance for that temperature, and is one of the most important of its physical constants. This law has been directly verified by its discoverer, and by Becquerel, Davy, Fechner, Kohlrausch, and others; and indirectly it has been verified for a great variety of substances with a degree of accuracy approached in few physical measurements. Lately, in discussing some experiments of his own, Dr. Schuster has raised the question whether after all Ohm’s law is only an approximation, the limit of whose accuracy lies within the region of experiment. We might suppose that the ratio ci was some function of C*, say FHR-8, where R is a constant very nearly equal to what has hitherto been called the specific resistance, and § is a small constant which, according to Dr. Schuster’s suggestion, would be positive. It is clear that = ceaif only be an even function of C, unless we admit wnilateral conductivity, for which there is no experi- mental evidence in a purely metallic circuit. A Committee of the British Association, appointed to consider the subject, were of opinion that it was of importance to attempt a further experimental verification of Ohm’s law. At the suggestion of Professor Maxwell, the experimental details of two methods of verification proposed by him were undertaken by the writer of this Report. Of the two experiments representing these methods the second is by far the most conclusive. It not only avoids the difficulty of eliminating temperature effects, which to a certain extent interfere with the first experi-. ment, but it pushes the verification of Ohm’s law very near the natural limit of all such verifications, viz. the limit of the solid continuity of the conductor. It has thus been rendered probable that experiment cannot detect any deviation from Ohm’s law, either in the direction indicated by Dr. Schuster, or in the opposite direction as suggested by Weber, eyen in wires that have been brought by the electric current to a temperature beyond red heat. A third experiment was also tried by the writer of this Report ; its result agreed with the others, but, owing to certain peculiarities, it is less conclusive than they are. It led, however, to interesting results of another kind, which * The current is supposed to be steady. + By definite is meant in a given physical condition, except as regards B.M.F. and flow of B, and temperature. The last is excepted because we are brought face to face with possible temperature variations ih the first experiment. + We suppose the conductor to be of unit length and unit section. It is of course the specific resistance which is in question ; and this, if variable, will depend on the current per unit of section. 40 REPORT—1876, seem to show, among other things, that conclusions respecting the accuracy of Ohm’s law cannot safely be drawn from experiments of the nature of those made by Dr. Schuster. First EXPERIMENT. Suppose that we had five resistance-coils, which, when compared with each other by means of the same current, were equal, say each =R. That is to say, if any two of the resistance-coils were inserted in the branches A B and BD of a Wheatstone’s bridge, the other two arms, AC and C D, being two other equal resistances, then the galyanometer G inserted between B and CG would indicate no current. Fig. 1. Suppose now that we replace the coil R in BD by four of the equal coils arranged in multiple arc, as in fig. 2, Then, if Ohm’s law be true (i.e. if resistance be independent of current), if p be the resistance between B and D, 1 ise we eae aaebi() 12M. By i.e. p=R, and there will still be no deflection in the galvanometer. But if Ohm’s law be not true, and the resistance be a function of the current, then, since the current through A B is nearly the same as in the first experiment, while that through BED and BF 'D is half, the resistances in BE, ED, BF, F D will be no longer equal to R, but either greater or less, and the galyano- meter will be deflected. Under the direction of Professor Maxwell, part of the funds at the disposal of the Committee were devoted to providing two sets of coils specially adapted fer the above experiment. One set consisted of five coils of silk- covered German silver wire (diameter ‘6 millim.), each of resistance as nearly as possible equal to 30 B.A. units. These were all wound together in the usual way round one bobbin ; the terminals consisted of ten pieces of stout copper wire, insulated from each other by a ring-shaped piece of ebonite, through which all of them passed. These stout wires were bent over, and ON OHM’S LAW. 4). cut as nearly as possible of the same length, so that their amalgamated ends might go in pairs into mercury-cups. The wire and bobbin were enclosed between two coaxial cylinders of sheet brass, which were fastened to the ebonite piece above, and connected by a ring of sheet brass below. The whole had a rough resemblance to a large spider. The other set consisted of two coils made of the same wire, and having each as nearly as possible the same resistance. They were arranged in the same way, except that the ter- minals of the same coil were adjacent. As the adjustment of the coils was necessarily not perfect, the experiment could not be tried exactly as described in the above scheme. I decided, therefore, to operate as follows :—First, to compare each coil of the five with the coil next in order; the differences between any two coils could then be found in terms of an arbitrary unit (the resistance of a tenth of a millimetre of the platinum-iridium bridge wire at the temperature of the room during the experiment); second, to compare each coil with the four others arranged in multiple arc, as before described. The results thus obtained were com- pared, as will be described further on. To facilitate these comparisons, the following arrangement of mercury-cup connexions was made for me by Mr. Garnett, of St. John’s College, the Demonstrator at the Cavendish Laboratory :— ~~ i i To a massive board are glued five large mercury-cups, made of boxwood, with a piece of amalgamated sheet copper at the bottom. Into these go the ten terminals of the five coils, so that there would be metallic connexion round all the five coils in series were it not that the cup A is divided by a piece of vulcanite, which insulates the two terminals in that cup. J is a stout copper bow connecting B and the lower division of A; to this bow is soldered one of the galvanometer terminals. Into the cups w and v dip the two terminals of one of the two coils. m is astout bow of copper connecting the upper half of A with uw. Another bow goes from v to F, one end of the bridge, which is the instrument used by the British-Association Committee of 1863, and will be found described at p. 353 of the Report (1864) of the Com- 42 - REPORT—1876. mittee on Electrical Standards. To mis soldered one of the battery terminals. The connexions on the right are similar to those on the left, and may be un- derstood from the diagram. The other galvanometer terminal goes to the contact-block L. The battery used consisted of twelve Leclanché’s cells, the whole internal resistance of which was about 13 B.A. units, its E.M.F. being about 16 times that of a Daniell. The whole resistance of the bridge from F to G was about ‘075. The galvanometer is an instrument made by Elliott Brothers, belonging to the British Association ; its resistance is about half a B.A. unit. Good contact between the feet of the copper terminals of the quintuple coil and the bottom of the mercury-cups was secured by placing a weight on the top of the coil; the spring in the terminals was then sufficient to ensure contact everywhere. In the arrangement figured in the diagram the coil p is balanced against a multiple arc, containing g and r in one branch, and s and ¢ in the other. To compare one single coil with the next single coil, / is removed, and one end of the galvanometer wire connected instead with the cup E, while m is made to connect the lower instead of the upper half of A with uw; with this arrangement the coil ¢ is balanced against the coil s. The coils in the quintuple coil are numbered 1, 2, 3, 4, 5; and in experi- ments with multiple are the coil between A and B is referred to as the “single coil;’’ in experiments with single coils those between D and E and E and A are called right coil (R.C.) and left coil (L.C.); the coils between w and « and w and v are called right and left middle coils (R.M.C. and L.M.C.), and are numbered 1 and 2. The bridge is read from left to right. Some preliminary experiments were made with the apparatus, which showed that the coils had been very well adjusted by the makers, Messrs. Warden, Muirhead, and Clark. It was found that with the arrangement described (the best at our command in the Cavendish Laboratory), the bridge could be read to a quarter, if not to an eighth of a millimetre. A small correction was found necessary for the magnetic field, due to the current in the bridge connexions; this was allowed for by adjusting a loop of the battery-wire till the galvanometer showed no effect when the battery was turned on. Thermoelectric currents in the galvanometer circuit, owing to heating from the hand at the contact-block, were avoided almost entirely by using two pieces of wood, which were interposed between the fingers and the block, and were continually changed so as not to get hot. The order of experiment was generally as follows :—The weight was ad- justed on the quintuple coil, the battery was thrown in for a moment by means of a treadle which closed the battery circuit ; if there was no direct effect on the galvanometer, the battery was thrown out, and contact made at the block ; the spot of light on the scale was watched through a reading- telescope, and if it was at rest* the battery was thrown in: the deviation indicated which way the block had to be moved to get a balance. Two or three trials in general sufficed to get the balance. The bridge was then read ; the middle coils were then reversed, the balance found, and the bridge read again. The difference of the readings gives the difference of the resist- ances of the middle coils, as may easily be shown (see ‘ Journal of Society of Telegraph Engineers,’ Oct. 1872). The middle coils being replaced as before, the quintuple coil was moved round one step, and the same process repeated. * On the avoidance of small thermoelectric effects, see below in the discussion of the second experiment. ON OHM’S LAW. 43 Formula of Reduction. Let the right-hand middle coil (No. 1) be taken to be 30 ohms, the bridge- wire being -075 of the same units. Let 7 denote the resistance of this coil, the unit being the resistance of a tenth of a millimetre of the bridge-wire, therefore __ 30x 10000 a oe Let the resistances of 1, 2, 3, 4,5 of the quintuple coil, measured in the same units, be tT+a, 7 t+h,7+y, es, mr Hence, comparing middle coil 1 with 2, 1 being on the-right, tha — are re (1) atG r+10000ta—¢) fe where 7+ D=resistance of middle coil 2, x the bridge-reading, a and b the resistances of the connexions at its two ends. This gives — 10000 —a& a—Bp={D—a—b+2(a—5000)} {1 utc to weet |x a7 all other terms being negligible. Now the greatest possible value of 10000—w is 6000, since the readings never went below 4000, and ee was never greater than 400. Hence the term involving 1000 —. = 4000000. ” ig less than A * 400x 6000 6 4000000 ~ 10 and is therefore negligible, since we do not read beyond tenths of a milli- metre. Hence we may use the formula a—B=D—a—b42(~—5000). . . . beats) Similarly, in comparing one coil against four, we get the formula a—](8+y+b+e)=D—a—b42(@—5000). . . (4) To find a—b, the “ bridge correction,” a reading is taken with the coils Fig. 4. arranged as usual either for a single experiment or for a multiple-arc ex- ‘periment: let this reading be x. Then the connexions are crossed, as in the 44 REPORT—1876. figure, by introducing two new pieces of copper and two more mercury-cups, the arrangement independently of the bridge being very nearly symmetrical : let the reading now be 2’. Assuming that the resistances of the movable cups and bows at the two ends are equal, =/ in one case, =k’ in the other, then P+k+a+l—2 Bs A GIELite eo P+k-+a+l—2 ate A PYO 2 oreo «(eA ASBB Similarly, al eae the e c v PQ a ao 7, AEB’ gi cae A ee P l P+Q+/ J babe at tay ot FGETS y oe eae {1+ P : P+Q+4l J’ ik ktatl—w k+i(a+b) satire Sisk Org h4+6+2° k’'4+3(a+6) =—1 A 2 +5 oS *,a—b=xe+2'—10000. A variety of experiments were made with the coils arranged sometimes in one way, sometimes in the other, and closely agreeing values of a—b6 were found varying from 52 to 58. Correction for want of Symmetry. Referring back to fig. 4, we see that in the arrangement for multiple- are experiments the connexions are not quite symmetrical. The copper bows were all nearly of the same length and thickness: let the resistance of one of them be 2b. Let also the average resistance of a mereury-cup be 2r. Then we get for the addition to 1(6+y+6+e), 7(2b4+10r)+6+7, for the addition to a 2b4+4r. Hence a—i(8+y +6+.€) is too great owing b , to the connexions by 3t5 Various experiments were made to find the value of +47, and all gave very nearly the same result. The following is a specimen :—A copper bow very slightly longer than those in the connexions was inserted by means of an additional mercury-cup, first on the right then on the left of the bridge ; the readings were 5032 and 4982, the difference being 50 ; .°. 2(b4+7)=50, 5% 12 We a” a ae The correction was actually taken to be 10. Limits of Temperature Effects. The coils were arranged for a multiple-arc experiment; the balance was ON OHM’S LAW. 45 taken at 3.25; the battery was then thrown in and kept in for about a quarter of an hour with the following results :— hm ae 38 25 5007 3 35 5020 3 42 5022 The reading therefore increased by 15, the greater part of increase taking place in the first 10 minutes. Another series of experiments were made with single coils against single, as follows :— Time of Obs. RM. R.C. T0| Aee De | 1 3 | 2 | 4914 These experiments were done as quickly 2 x , | 5187 | 223] as possible ; the balance, already approxi- 9 2 1 | 5226 mately known, was found by three or four 1 , | 5008 | 218} instantaneous contacts, so that the coils were as little heated as possible. The battery was thrown in at 12.36 and kept in, the coils being as in last experiment. At 12.36...| 1 2 | 1 | 5008 |218} The idea was to get 2 heated and then 12.41 1 eet | 501s compare it again with 3, which had been to i244 2 »» | 9 | 5224 | 211] very little if at all heated. 12.56/| 1 Slee aioOls to1.00|] 2 ecules 223 | 205 13. 1 é 2 | 4929 2 ye ie ales! (209 EB? ss 1 5 | 4 | 5036 |209| Two fresh coils were taken, the middle 1.25.. rf a » | 5036 coils being as before at difference 209, 1.30...) 2 al tameleo2ee 198 Crossed connexions ......++ 4818 | ... | Bridge correction 52. ¥ Reducing these experiments by the formula given above we get D—52 : D OF 2(a—5000). Time, 223 | 4914 =n B-y 12.30 218 | 5008 +182 a—p 12.386 211 5013 +185 BAe 12.41 205 | 5018 4-189 sich 12.56 209 | 4929 + 15 B-y 1.8 | 209 | 5036 +229 (—eé 1.8 198 | 5036 +218 o—e€ 1.80 Several important inferences may be drawn from these experiments. 1. The difference of resistance between the middle coils decreases as the temperature increases, and that so regularly, that the value of D may be used _as a sort of thermometer, indicating how nearly these coils are kept at the ‘same temperature during any series of experiments. This fact shows the -propriety of using the appropriate value of D for each case in our reducing formula instead of the average value. 2. The coils 4 and 5 possess the same property, though in a less degree, 3, The coils 1 and 2 possess this property to a very slight extent. _ 4, The greatest effect that could be produced in a reasonable time on the 46 REPORT—1876., difference between 2 and 3, by heating 2 and comparing it with 3 scarcely heated, if at all, was 16. The above peculiarities suggested to me to make a set of experiments on the plan of keeping the current going as much as possible. It was hoped that thus a certain limiting state, as regards temperature, would be arrived at, which from the construction of the coils would in a great measure be independent of small variations of temperature in the experimenting-room *. This method of proceeding would not introduce any error in the com- parison of single coil with single, and the error introduced into multiple-are experiments would be regular and could be allowed for. The last of the sets of experiments given below was conducted on this plan with satisfactory results. Tabular Scheme of best Experiments. Single Coil;with Single. Multiple Are. RMORC|LO| 2 | D. |RMolSle) | p. 2 2 | 1 | 52384 Starting fresh and work- 1 » | 9 | 5022 | 212 ing quickly. 1 : 2 | 4921 2 » | » | 5135 | 214 2 3 | 5074 1 ” ” 4862 212 1 4 | 5046 2 11) 99 1) 025d) 209 2 5 | 4973 il » | » | 4760 | 218 2 2 7 1 | 5228 1 5000 The multiple-are experi- 1 Sell Airspeed bes (M7 2 * 5223 | 223 | ments were started fresh ; 1 | Gam ats 768 2 5 | 5035 battery reversed, but no dif- 2 » | o» | 4982 | 214 1 Pr 4810 | 225 | ference found, The single- 2 5 | 4 | 5250 1 4960 coil experiments followed 1 Fe so} pdeen) 2 2 3 5180 | 220 | some little time after, some 1 4 | 3 | 4861 2 5106 experiments with cups and 2 Me Nie sai. UTS eerie 1 FP 4891 | 215 | bows haying been made in 2 8 | 2 | 5140 1 4892 the interval. 1 39 | 99 | BORD LS 2 bs 5110 | 218 2 2 | 1 | 5228 1 1 5024 These experiments were 1 a ltcs,: | OLS e A200: 2 4 5227 | 203 | worked slowly, the current il 1 4771 2 5032 being kept on as much as 2 . » | 4972 | 201 1 +E 4825 | 207 | possible. The single-coil ex- 2 5 | 4 | 5238 iL 4963 periments came first. The 1 - » | 5038 | 200 2 25 5170 | 207 | last line gives a control ex- 1 4 | 3 | 4861 2 5089 periment. The correction 2 | o -| 5067 | 206 if 55 4884 | 205 | for magnetic field was for- 4 3 | 2 | 5143 1 2 4905 gotten in the multiple-arc 1 » | | 4935 | 208 2 Pe 5108 | 203 | experiments, and in conse- aes) ——— quence 4 must beadded tox 1 2 | 1 | 5024 2 1 5228 throughoutin the second set. * No special means of keeping the double and quintuple coils at a constant temperature was resorted to. The object was not to find the resistances of the coils at any definite temperature, but to compare them under the same circumstances as regards temperature. It was therefore thought that any attempt to surround the coils with water, &e. would introduce greater errors than would arise from small variations of temperature in the room during the experiment. : ON OHM’S LAW. 47 Reduction and Comparison of the foregoing Experiments. D—58 Diff. D. | «. Fs D.| 2. sl F00y)| Cale. | Obs. 2(a— 5000). + "| ale, | 212/5022} +198 {198 The third column gives 2144921; — 2 /196 the values of a—A, | 14 212/4862) —112 84) B—y,y—6,0—¢,e—a; 209|5046) +243 |327) the fourth the values 2138/4760) —3825 | of a—B, a—y, a—d, = —-|| a—e, caleulated from + 2 these. (217/5011) +181 181)|223)5000 +165 +184;— 29)/The seventh and eighth | 215|4925} + 7 |188)218\4892) — 66 |— 42/— 24| columns give the values 24 217/4861; —119 69)/215|4891 — 69 — 51/— 18} of a—3(B+y+6+¢6), | 211/5039} +231 |300)/220\4960) + 72 |+4 98\— 26) B—i(a+y+6+e), ke. \ 214/4768) —308 225/4810 — 223 —191)— 32| observed in multiple- ——— | —_|—- || |__| ----———_|--|-_| are experiments, and - 8 —131 —129) calculated from the values of a—B, a—y, &e. before found. 200/5028) +204 |204)/203)5028} +197 |+4217;— 20)/The last column gives (Sos 4935, + 26 |230/|203/4909 — 41 — 388/— 3] the excess of the ob- 34 206|4861) —124 106}|205/4888 — 81 — 70\— 11) served over the caleu- 200/5038! +224 |330)|207/4967 G9 + 85)— 6) lated values of 2001/4771; —809 209|4829 —197 —195|\— 2) a-4F(B+y+6+6), ke. + 21 — 43 — 42 | N.B.—In the last set of experiments 52 was used instead of 58 as the bridge correction. The first thing to remark is the smallness of the sums of a—/, B—y, y—6, 6—e, e—a, as found from single-coil experiments ; the sum is theoreti- cally zero, and the largest deviation is about 20, which divided by 5 gives only 4 tor the average error of a determination. Here no error from want of symmetry comes in, and errors from irregular temperature effects very nearly balance each other. In the next place, taking the multiple-arc experiments of series No. 2, we see that there is a deviation of the observed from the calculated values of a—7(B+y+é+e) which averages 26; and here, from the way the experi- ments were conducted, the temperature disturbances are probably very small. Again, take the multiple-arc experiments of series No. 3. Here, from the’ manner of experimenting, the temperature effects will appear. We found that the greatest effect we could produce on one of the coils in a reasonable time was about 15; supposing that the whole of this was manifested in the single coil, we should get a quarter as much in each of the coils in the multiple are (because the current is halved), that is, we have 3 of 15 alto- gether in a—i(B+y+é+e); this necessitates a correction of about 10 to be subtracted from the observed values. This is clearly the maximum correction, for after the first experithent we turn into the multiple-arc coils that have already been fully heated. Supposing, however, that we apply the fuil correction in each case, we get for the average difference —18. This deviation is in the direction indicated by Schuster’s experiments, but 48 REPORT—1876. it is excessively small: suppose we call it —20 for convenience of calculation ; . Be Re ee rel this corresponds to the fraction -y55595=200,000 of 30 ohms. But the whole deviation is probably introduced by some slight defect in the apparatus, and part at least can be accounted for ; for it occurred to me, in looking over the results quoted above, that a defect in the insulation at the divided cup would partly account for such a deviation. Suppose that the divided cup offered a very large, but not infinite, resistance f to the passage of the current, then the single coil in multiple-are experiments would : ; ly eed be replaced by a multiple arc of resistance R', where Ri=30t 7 Hence R= 30— 30? Now let us find what 7 must be to give a decrease of 20 in cur observed value of a—7(B+yté+e): Orv e2p * f 10000 f=6,000,000 that is, f=6 megohms. Curiously enough, when I proceeded to measure the insulation resistance of the divided cup it came out very nearly 6 megohms ; but the insulation resistance between any two of the remaining cups was found to be about 12 megohms, which reduces the correction somewhat. The complete solution of the problem would be complicated ; but we may approxi- mate by considering each of the coils in the multiple are replaced by a multiple arc whose arms are 30 ohms and 12 meghoms respectively ; this requires that /3, y, d, e should each be reduced by 10, Hence the whole reduc- tion in a—2(8+y+é6+e) would be on this supposition 10, It would really be somewhat less; however, this would almost bring the deviation between observation and calculation within the limits of experimental error, Any remaining difference is probably due to a defect in some mercury-cup in the multiple arc, for there being more there than on the other side of the balance the chance of a defect is greater. It ought ‘to be mentioned that the insulation of the quintuple coil was tested, and found in every case to be of a higher order of magnitude than a megohm. Some time after the series of experiments just described, I dismounted the mercury-cups from the stand, which had meantime been carefully dried on the hot-water pipes in the laboratory. Each cup was remounted with a piece of gutta percha between it and the board ; and the divided cup, which was found radically defective, was replaced by two mercury-cups on separate ‘pieces of insulating material. The insulation between every pair of cups was then tested afresh and found in every case of a higher order than a megohm. The experiments were then repeated with the altered stand. The sensi- bility of the arrangement was about the same as before, although a less electromotive force was used (10 cells). The results were much the same as before, except that the sum of the values of a—j7(3+y+o+e), &e. was now much smaller, two experiments giving —31 and —34. Dividing this by 5, we get —6 for the average deviation, which is very small. The fact that we still get a result in the same direction shows that this is not an accidental error; but it might very well be accounted for by some of the suppositions mentioned already. It might also arise from over-correction for symmetry.) ON OHM’S LAW. 49 On the whole, therefore, we cannot conclude that there was any deviation from Ohm’s law under the circumstances of this experiment. It is hardly worth while to estimate the value of this experiment quantitatively, as the second experiment now to be described is so far superior in this respect. Srconp EXPERIMENT. Introduction, by Prof. Maxwett, The service rendered to electrical science by Dr. G. 8. Ohm can only be rightly estimated when we compare the language of those writers on electri- city who were ignorant of Ohm’s law with that of those who have understood and adopted it. By the former, electric currents are said to vary as regards both their ‘quantity ” and their “intensity,” two qualities the nature of which was very imperfecly explained by tedious and yague expositions. In the writings of the latter, after the elementary terms ‘“ Electromotive Force,” “Strength of Current,” and “ Electric Resistance ” have been defined, the whole doctrine of currents becomes distinct and plain. Ohm’s law may be stated thus :— The electromotive force which must act on a homogeneous conductor in order to maintain a given steady current through it, is numerically equal to the product of the resistance of the conductor into the strength of the current through it. If, therefore, we define the resistance of a conductor as the ratio of the numerical value of the electromotive force to the numerical value of the strength of the current, Ohm’s law asserts that this ratio is constant—that is, that its value does not depend on that of the electro- motive force or of the current. The resistance, as thus defined, depends on the nature and form of the conductor, and on its physical condition as regards temperature, strain, &c. ; but if Ohm’s law is true, it does not depend on the strength of the current. Ohm’s law must, at least at present, be considered a purely empirical one, No attempt to deduce it from pure dynamical principles has as yet been successful ; indeed Weber's latest theoretical investigations* on this subject have led him to suspect that Ohm’s law is not true, but that, as the clectromotive force increases without limit, the current increases slower and slower, so that the “resistance,” as defined by Ohm’s law, would increase with the electromotive force. On the other hand, Schuster t has described experiments which lead him to suspect a deviation from Ohm’s law, but in the opposite direction, the resistance being smaller for great currents than for small ones. ' Lorentz+, of Leyden, has also proposed a theory according to which Ohm’s law would cease to be true for rapidly varying currents. The rapidity of variation, however, which, as he supposes, would cause a perceptible deviation from Ohm’s law, must be comparable with the rate of vibration of light, so that it would be impossible by any experiments other than optical ones to test this theory. The conduction of electricity through a resisting medium is a process in which part of the energy of an electric current, flowing in a definite direc- tion, is spent in imparting to the molecules of the medium that irregular agitation which we call heat. To calculate from any hypothesis as to the molecular constitution of the medium at what rate the energy of a given * Pogg. Ann. 1875. t+ Report of British Association, 1874, { Over de Terugkaatsing en Breking van het Licht, Leiden, 1875. 76, E 50 REPORT—1876. current would be spent in this way, would require a far more perfect know- ledge of the dynamical theory of bodies than we at present possess. It is -only by experiment that we can ascertain the laws of processes of which we do not understand the dynamical theory, We therefore define, as the resistance of a conductor, the ratio of the numerical value of the electromotive force to that of the strength of the current, and we have to determine by experiment the conditions which affect the value of this ratio, ; Thus if E denotes the electromotive force acting from one electrode of the conductor to the other, C the strength of the current flowing through the conductor, and R the resistance of the current, we have by definition and if H is the heat generated in the time ¢, and if J is the dynamical equi- valent of heat, we have by the principle of conservation of energy 2 E — — 2+ —— JH=ECt=RO%=—H t. The quantity R, which we have defined as the resistance of the conductor, can be determined only by experiment. Its value may therefore, for any thing we know, be affected by each and all of the physical conditions to which the conductor may be subjected. Thus we know that the resistance is altered by a change of the temperature of the conductor, and also by mechanical strain and by magnetization. The question which is now before us is whether the current itself is or is not one of the physical conditions which may affect the value of the resist- ance ; and this question we cannot decide except by experiment. Let us therefore assume that the resistance of a given conductor at a given temperature is a function of the strength of the current. Since the resistance of a conductor is the same for the same current in whichever direction the current flows, the expression for the resistance can contain only even powers of the current. Let us suppose, therefore, that the resistance of a conductor of unit length and unit section is — ¢ (1+sc?+s'c+ &e.), where v is the resistance corresponding to an infinitely small current, and c is the current through unit of section, and s,s’ &c. are small coefficients to be determined by experiment. The coefficients s, s’ &c. represent the devia- tions from Ohm’s law. If Ohm’s law is accurate, these coefficients are zero ; also if ¢ is the electromotive force acting on this conductor, e=re(1+sc?+s'c'+ &e.). Now let us consider another conductor of the same substance whose length is L and whose section is A; then if E is the electromotive force on this con- ductor, and ¢ that on unit of length, E=TLe. Also if C be the current through the conductor and ¢ that through unit of area, — C=Ae¢, ON OHM’S LAW,. 61 Hence the resistance of this conductor will be Hes aan (+55 ca tke.) Now let us suppose two conductors of the same material but of different dimensions arranged in series and the same current passed through both : ati (4a +&e.); sC2 ae +8.) where the suffixes indicate to which conductor the quantities belong. The ratio of the resistances is R, DL, A, i 2 RTA, ie (1450 (m ? oa) i &e.), Hence if Ohm's law is not true, and if, therefore, any of the quantities s, s’, &e. have sensible values, the ratio of the resistances will depend on the strength of the current. Now the ratio of two resistances may be measured with great accuracy by means of Wheatstone’s bridge. We therefore arrange the bridge so that one branch of the current passes first through a very fine wire a few centimetres long, and then through a much longer and thicker wire of about the same resistance. The other branch of the current passes through two resistances, equal to each other, but much greater than the other two, so that very little of the heating-effect of the current is produced in these auxiliary resistances. The bridge is formed by connecting the electrodes of a galvanometer, one to the junction of the fine wire and the thick one, and the other to a point between the other two resistances. We have thus a method of testing the ratio of the resistances of the fine wire to that of the thick one; and by passing through the bridge sometimes a feeble current and sometimes a powerful one, we might ascertain if the ratio differed in the two cases. But this direct method is rendered useless by the fact that the current generates heat, which raises the temperature of both wires, but that of the thin wire most rapidly ; and this makes it impossible to compare the effects of strong and weak currents through a conductor at one and the same temperature. It is also useless to work with weak currents, as the effect depends on the square of the current, and is so small as to have escaped observation in all ordinary experiments. Again, if we were to use a single very strong current acting for a very short time, we should not be able to observe the galvanometer ‘in a satisfactory manner. In fact it was found in the experiment that currents which lasted for a sixtieth part of a second produced a heating-effect which interfered with the measurements. The experiment was therefore arranged. so that a strong current and a weak one were passed through the bridge alternately ; and when the bridge was so arranged that the galvanometer was in equili- brium, the direction of the weaker current was reversed. If Ohm’s law were not true, the cogation of equilibrium for strong currents would be different EQ R= 52 REPORT—1876. from that for weaker ones, so that when the weak currents were reversed there would be no longer equilibrium. Since, in point of fact, the reversal of the weaker currents did not affect the equilibrium, it follows that the bridge was in equilibrium for the weaker currents as well as for the stronger ones, and therefore the conditions were the same for both, and Ohm’s law is true to within the limits of error of the experiment. The mode in which the actual strength of the currents was measured and the limits of error ascertained, are described in the following Report by Mr. Chrystal. Report on the Second Experiment. By G. Curysrat. As has been pointed out by Professor Maxwell, the change in the specific resistance of a linear conductor, if there be any such change owing to increase or decrease of the current, will depend on the amount of current that. passes through unit of area of its section; so that if C be the whole current passing, r the specific resistance for infinitely small current, 7 the length, w the section, and h a constant depending on the nature of the conductor, then the resis- tances of the conductor will be “(1 — in) 5 w w 2 or if R be the resistance for infinitely small currents, R( 1 -n=) *, It is clear, therefore, that by making up a resistance of very fine wire, say s4y of an inch in diameter, any such effect as that we have been looking for would be greatly multiplied. Accordingly the following experiment, the principle of which is due to Professor Maxwell, was undertaken by the writer of this Report. The figure represents a Wheatstone’s bridge, in which the resistances AB and BD are each equal to a (in the actual experiment 30 ohms), AC aresistance made up of a thin wire whose resistance for in- finitely small currents is R (this we suppose to be duly corrected for temperature, as will be explained by-and-by), and partly of a length of the thick platinum-iridium wire of the B.A. bridge, whose resistance is a. CD consists of a resistance composed of thick wire equal to R, and of the rest of the bridge-wire, whose resistance is J — a. With a current C, w being the section of fine wire, its resistance is = R(1—,C*), where aoe By 2Ra : : If as carers be the approximate resistance of the whole bridge (we suppose that there is nearly a balance), B that of the battery circuit; then E being the electromotive force of the battery, > & ee ap—Pe. * The sign of 4 is chosen according to Schuster’s suggestion. ON OHM’S LAW. 53 Then A denoting the determinant of the system of resistances (see Max- well’s ‘ Electricity,’ vol. i. p. 399), we have g denoting the current in the galvanometer, alt en g= it —2e4+ RuPE’}. Se tal eee eco Fs (1) From (1) it follows at once that the greater E, the further to the right the balance will be, provided p is >0. Let us now, instead of keeping up an electromotive force E. constantly, make an alternation some hundred times a second between an electromotive force E and an electromotive force yE*; then supposing each to operate for an equal time, the whole current through the galvanometer is given by g= 5x {(U—20)(1+y)E+R pRB +y)} Bc ener ee gay if the electromotive force has in both cases the same direction, and by 9=5x{U—20)(1—yE+RpPEL—y} « sh tases a he?) if the directions are opposite. It appears, therefore, as was obvious without calculation, that the values of w which give a balance are neither the same in the two cases (2) and (3), nor equal to that in the case of either electromotive force acting continuously. _In fact the balance is an apparent one if # be >0, due to the fact that we are in case (2) as much under the balance for the larger electromotive force (qua effect on the galyanometer) as we are over that for the smaller, so that the needle is kicked equally this way and that so rapidly that it remains still. Similar reasoning would show that the balance for case (3) lies most to the right of all. In fact the values of a are :— Smaller electromotive force alone « = 3{1+ RuP*y?E*}, BBs) 5 teers: «405 os 0e Peden: we = 2114+ RuP(1—-y+y)h’}, Larger electromotive force alone w = 3{1+RyuP?E"}, BERR Gren we Saielne welch nx = v= Z{l4+ReP1+y4+y7/)E}, which are evidently in ascending order if y be <1. Suppose now we find the balance for case (2) and then reverse our smaller electromotive force ; the balance being thus disturbed, there will be a current through the galvanometer ; and in order toexpcriment at the greatest advan- tage this must be made a maximum. Substituting the second of the above values of w in formula (3), we get 9=SRpPEY—y) ee which is a maximum as far as y is concerned when y=}, the value of g being then aRP?E° i De a AR . . . . ° ° . . . . (5) The advantage of this method of experimenting is that it eliminates to a great extent the temperature effect, which is similar to the effect we are looking for, except that it depends on the time, which the other probably would not * N.B. In what follows y is supposed < 1. 5d REPORT—1876. do; and it is of course opposite in direction. If we make our alternations quick enough the wire will not cool sensibly during the smaller current, nor heat sensibly during the larger, but will settle down to a mean temperature between that due to the larger and smaller currents. In the above calculation we have supposed the resistance of the fine wire for infinitely small currents to be that corresponding to this mean tempera- ture, which will be constant throughout the experiment provided the electro- motive forces do not vary. If, however, the alternations are not quick enough to ensure temperature- equilibrium, then the thin wire will be hotter during the passage of the larger current than it is during that of the smaller; and there will be an effect opposite to that we are looking for, a result which appeared-in many of the experiments. The experimént proved very difficult in practice, chiefly owing to the diffi- culty experienced in getting a good alternator; and it was only after a great many total or partial failures that any thing like success was attained. A sketch of the progress of the experiment, with an account of the more im- portant difficulties, and how they were finally avoided or overcome, may be of some interest. In the first place the galvanometer indications in a Wheatstone’s bridge, arranged as above described, are somewhat peculiar. Suppose we are somewhere near a balance for some temperature of the thin wire above that of the room; then on turning on the current there is a sharp kick in one direction, say to the right, then a slower but still tolerably quick swing over to the left, and then a gradual subsidence back to zero or thereabouts, which may last for half an hour or longer. If this were due solely to variation in the resistance of the thin wire the curve of time-resis- tance would be of this nature— Fig. 6. It had been found that the thin wire was very sensitive to air-currents, merely blowing towards.it from a considerable distance sending the spot off the galvanometer-scale ; in fact to get any approach to steadiness the wire had to be enclosed in a box, and latterly it was enclosed in a narrow tube, and that again loosely rolled in a silk pocket-handkerchief, and the whole enclosed in a box, It was therefore at first suspected that the peculiarity in question was due to air-currents ; but some experiments with the wire in an exhausted tube showed that it was due to some other cause. This cause was found in the slow heating of the thick wire against which the thin wire was balanced; and some obvious experiments were made confirming this con- clusion*, * The behaviour of the galvanometer is therefore explained in this way :—The first sharp short kick is due to the fact that before the thin wire is heated its resistance is much smaller ON OHM’S LAW. 55 This slow variation of the balance was sometimes avoided by letting the batteries work until it had died away, and sometimes it was allowed for by suitably arranging the order of experiment. As it was of considerable importance to have a battery which could be relied on for constancy for some time, six large Daniells were charged for the purpose. They were cells intended for a Thomson’s battery, but were fitted up for convenience with copper plates 18 inches square, upon which was strewed sulphate of copper, which again was covered with a thin layer of sawdust moistened with zinc sulphate, and on the top of this was placed a heavy grating of zinc. ‘Two piles were made consisting respectively of four and two of these elements, and were used in most of the experiments. The internal resistance of these piles ran to about 4 and 3 ohms respectively. The electromotive force was repeatedly tested during the experiments. At first a “‘ Morse key ” worked rapidly by the hand was tried for an alter- nator; this method, though leading to no definite results, seemed to show the possibility of success. Then a rotating alternator driven by hand was tried; but it was found that the results though much better were still very much disturbed by the irregularities of the driving. Next a rotating alter- nator was made by Mr, Garnett and fitted to a Jenkins: governor; this also after repeated trials was given up, the main difficulty being that of getting up sufficient speed without introducing so much resistance as to go beyond the range of the governor. Some of the results got with this arrangement were fairly good, however, and will be given below. In the arrangement adopted in the final experiments the alternation was managed by means of a pair of electric tuning-forks, For the use of these during the Lent term I am in- debted to the kindness of Dr. Michael Foster. Final Arrangement. Fig. 7, p. 56, gives a scheme of the final arrangement. AB is the bridge already mentioned in the Report. EGC is the galvanometer circuit. Between D and E and E and F are inserted two resistances of 30 ohms each; W is the fine wire, H a coil of thick German-silver wire of resistance nearly equal to that of the fine wire, K a small resistance-box from which twentieths could be got, the final adjustment being of course made by moving the block C. Dis connected with the stem of the tuning-fork PQ, whose prongs are each provided with a dipper, and corresponding to the dippers are two mercury-cups whose heights are adjustable. M and N are the piles of four and two Daniells. O isa commutator, by means of which the smaller battery can be thrown in either way, or thrown out altogether as desired. One terminal of the commutator goes to the cup T, the other to F. The other cup, S, is connected with one pole of the larger battery, the other pole of which is connected with F through a key, L, by opening or closing which the battery M may be thrown out or in at pleasure. The rest of the figure re- presents an auxiliary battery, U, whose circuit goes through another fork, V W, working a break at W, and through the electromagnets of the forks VW and PQ. This latter battery and fork therefore simply drive the fork PQ. than that corresponding to a balance ; the quick swing in the opposite direction is due to the sudden rise of temperature causing a corresponding increase of resistance; the slow yeturn movement is due to the increase of the balancing resistance owing to the gradual development of heat in the thick wire. 56 REPORT—1876. . Fig. 7. ier he iia saps a \ The action of PQ is obvious. When the prongs approach cach other the upper dipper is depressed into the mercury in S, while the lower dipper is raised out of the mercury in T, so that the current of the larger battery passes, and vice versé when the prongs separate; and it is easy enough by throwing a galvanometer in instead of one of the batteries, and then setting the fork going with the other on, to adjust the break in such a way that there is perfect independence between the two currents. This test was in fact ac- tually applied either at the beginning or end of each set of experiments. We have thus alternately sent through the bridge certain definite fractions of the whole current due to the large and small batteries. What fractions these are will depend on the nicety with which the break is adjusted (with perfect adjustment it would be one half of cach), and also on the state of the mercury surfaces and of the dippers. As may be imagined, the main difficulty of the experiment lay in getting the dippers to work properly. Several sorts were tried; plain copper amalgamated was found to act fairly well, but broad spade-shaped pieces of platinum-foil answered on the whole best. The sur- face of the mercury was covered with spirit, which is effectual so far in pre- venting the spoiling of the surface; but ultimately the cups get clogged with finely divided mercury, and then all regular action is at an end. It was ON OHM’S LAW. 57 found, however, that with some care the break could be got to work long cnough to allow of good results being obtained. On account of this gradual alteration of the break, and for other reasons as well, it was of vital importance to be able during the experiment to obtain some measure of the amount of current that passed as representative of the large and small current respectively ; for the experiment would obviously be nugatory if, instead of the smaller current being nearly half the larger, it became, owing to deterioration of contact in the cup 8, equal to what ought to be the larger current. To provide for this the experiments were conducted as follows :—The balance was found, whether for larger currents alone or smaller alone (acting directly or with the fork going), or for both together in the same or in opposite directions; then the block was moved as quickly as possible 6 centims. from the position of balance, and the deflection which then appeared was read off; this deflection is approximately proportional to the current. Knowing then the electromotive force of either battery and its internal resistance, one could not only tell whether the currents were passing - nearly in the right proportion, but also estimate roughly how much current absolutely passed in each case. In some of the best experiments a more ac- curate method was adopted :—The point D was “put to earth,” and the point E connected by means of a long insulated wire with one pair oi the quadrants of a Thomson’s electrometer in the flat of the laboratory below the room where the experiment was carried on; the other pair of quadrants being “put to earth,” the deflection observed on the electrometer-scale was a direct measure of the electromotive force between D and E—that is, of the quantity denoted Pp above by B eae Before giving the quantitative results obtained from the most satisfactory experiments, it may be well to explain the principle on which these have been selected from the others. In all the experiments quoted there was either something remarkable, such as a high battery power, &c., or else the balances were obtained under very fayourable circumstances, the spot of light being very steady, and the proportions of current passing, as indicated by the sensibilities * or electrometer measurements, being near the theoretically best - amounts. Often where the breaks were not working satisfactorily, by work- ing quickly a qualitative experiment could be made, the behaviour of the galvanometer indicating to an observer practised in the experiment that the proportions of current passing were not far wrong; and often part of an experiment could be made perfectly satisfactorily, and then the apparatus would go out of order. But in all the experiments, whenever the results wero at all intelligible (regular), the conclusion pointed to never differed from that given by the best experiments, viz. either the balance for the currents in opposite direction lay more to the left than that for the currents in the same direction, or the two coincided. Of this the observer spared no trouble in stag himself even in experiments that were quantitatively utterly valuc- oss. The first set of experiments quoted, which are not of much value quan- titatively, may serve to illustrate what has just been said. In this set the time is given because the experiments were made during the slow heating- effect already alluded to. The spot of light was not perfectly steady, though much steadier for the + — balances than for the others; the bridge-reading is given to tenths of a millimetre, though of course in the present case for * The deflection due to six centimetres deviation from balance is called the sensibility. 58 REPORT—1876. the + + balances accuracy to less than a millimetre was not attained. The alternator was the rotating piece made by Mr. Garnett, driven by the governor, which, judging by the regularity and smallness of the oscillations of its brake-wheel, went very uniformly during the whole experiment. The rate of revolution was about three turns (causing as many alternations) per second. The sensibilities for + + and + — were respectively about 150 and 45 during the experiment, so that the large and small currents would be proportional to about 97 and 52 respectively. The fine wire was a small length of German-silver wire =, in. in diameter, whose resistance was about 7:3 ohms; and the counter-balancing resistance was 7-3 ohms, taken entirely from the small resistance-box. The governor being started, the batteries were set on at 4.6. Time. | Large Battery. | Small Battery. | Bridge. 4.15 + _ 5880 AT 5 + 5980 18 “5 = 5805 23 4 ot 5770 .25 i = 5518 AT oF = 6612 49 aie ae 6785 51 + ++ 7032 52 + - 6478 5D a0 sf 6820 DT se = 6418 5.00 + + 6605 5.10 De = 6308 Tt will be seen that with some little irregularity the balance on the whole went steadily to the right during some three quarters of an hour. In one point all the observations agree, viz. that the + — balance is more to the left by 1 to 3 centimetres than the + + for the corresponding time, If AR be the amount by which the average resistance is less for the smaller than for the larger current, then taking 250 as the difference between the balances, we get easily, from the formule given above (our unit of resistance being the resistance of +}, millim. of the bridge-wire, 7. e. +}$j> ohm), 250 : AR = 7 = 500 (taking y =3). Now the variation in resistance of German silver being about -044 per cent. per deg. Cent., we get for 1°C. on 7-3 ohms a variation of about 430 in our present units. Hence the average temperature of the thin wire was some- thing over 1° C. less during the smaller than during the larger current. Neither the magnitude of the cooling effect nor the irregularities in the progression of the balance in this experiment is to be wondered at, since we know that air-currents have a very powerful effect in cooling the thin wire; and here the wire was merely enclosed in a box to protect it from air- gusts, but was otherwise unprotected. We ought therefore to expect very little of this effect in most of the following experiments, where the alterna- tions were 20 times as fast, and where the wire was enclosed in a narrow tube protected from temperature variations. In the experiment next quoted, the alternations were made by means of ON OHM’S LAW. 59 the tuning-forks, and were at the rate of 60 per second. The resistance of the thin wire was very nearly the same, and it was enclosed in a narrow tube. The four Daniells had run down a good deal, being not quite equivalent to three, and the two had varied in proportion. The resistance which balanced the wire was, exclusive of the bridge-wire, 7-25 ohms. Large Battery. | Small Battery. Bridge. Sensibility. + + 5140 + - A little to left. =f ap ; + - No difference. as =e aie 95 ot = 45 IF 70 sce te 20 It will be seen that the effect that was so conspicuous in the first experi- ment scarcely appears here at all. It was in factso small that its appearance might be due to progress of the balance in the interval between the five observations. : In the next experiment the wire had a resistance of about 4-4 ohms; the material was German silver, and the diameter the same as before. The resistance against which it was balanced was a German-silver wire of about -12 centim. diameter, wound on a..bobbin, the resistance of which was 4-45 ohms. The Daniells had been fresh charged, and were arranged in piles of four and two as usual, the respective internal resistances being about 5 and 3. The small resistance-box was on the left with the thin wire. L. B. | 8. B. Box. | Bridge. | Sensibility. + + 0-00 2165 165 + _ 0:00 2165 42 Here the dippers were slightly adjusted. = = 0:00 2330 53 + =F 0-00 2330 170 vad 0-00 4310 105 + 0-05 5940 51 The experiment is marked in the laboratory book as very steady. It will be remarked that the sensibilities are large and well proportioned; for if we had theoretically perfect adjustment, the sum would have been 156 and the difference 54, as against 170 and 53. The + + balance is of course much more delicate than the + —; but even for the latter (6 centimetres giving, say, 54) we have 8 scale-divisions to a centimetre, so that we may rely on our + — balances to about a millimetre. This experiment therefore indicates a coincidence of the two balances within -0016 per cent. A good many experiments were tried with higher electromotive forces ; but though qualitative results of some interest were got, sufficient steadiness could not be obtained to make the results of use quantitatively. In most of these the thin wire was over a red heat; in fact in many of them the experiment ended with the melting of the wire, In general there appeared to be a good 60 rErort—1876, deal of the effect due to temperature oscillations already referred to. In one experiment in particular in which a Grove’s battery was used, with alterna- tions at the rate of only thirty per second, this effect came out very strong, the spot swinging off the scale when the smaller battery was reversed. Without dwelling on these, I proceed to give the results of the final set of experiments, which were in every way by far the most satisfactory. In the three following experiments the Daniells were used as before ; the alternations were made by means of the tuning-forks at the rate of 60 per second. Three wires were experimented on, a platinum, a German-silver, and an iron wire. The balancing resistance was the German-silyer bobbin with small resistance-box, which was on the left, except in the second experi- ment, where it was on the right. The electromotive force between D and F was now found directly by the electrometer; as a control the sensibilities are given as well. New spade-pointed platinum dippers were used, and answered admirably during the whole time the experiments were going on. . =. |e Sensi- | Hlectro- L. B. | 8. B. | Box. |Bridge. bilities!| bmnekex ®. ipeeeen Piltetidl eo ah 906i) ali0l) Bb alone wee | sal Oe] 409 176; 1) BBs (gos im. diameter, Ns ° 20 Very steady. ‘042 millim.). gfaton Sat gaia nits sh , ee sane) oor 2 Ys) z09 im. diameter, 43 ose Ee ee 257 Very steady. ‘051 millim.). | spews ue aac fe 118 + + 4:25 | 2090 | 170 368 i (3) Fe wire + |.— | 425 | 2090| 62 | 189 || Perfectly »|(14millim. diam). + ee 535 bine S00 255 steady. dis: + 1i4 In the last set of experiments a higher electromotive foree was used, viz. four cells of Grove and two, every thing else being as before. The same three wires were experimented upon, but with perfect success in the case of the iron wire only. In the experiments on the other two, although the electrometer readings were very steady and satisfactory, yet a steady balance could not be obtained; still it could be seen that the + + and + — balances did not differ by much; it seemed that there was, in the case of the German-silyer wire, a tending towards the effect so often alluded to. The following is the experiment with the iron wire :— Box “de Sensi- Electro- | LB. | 8. B. on left. Bridge. bilities. meter. ay te - 4:25 | 690 150 307 | eee aE ah 4:25 | 690 | Off scale 895 Perfectly pera « aero. eels “ale Merete, all eG SEO) as Ol steady. - (sl) apse + ooh 271 Using the additional data that the resistance of the metre of platinum- iridium wire on the bridge is ‘075 ohm, and that Latimer Clark’s Standard Cell (1-457 volt) produces a deflection on the electrometer used of about 320 divisions, we get roughly the following results (e denotes the electromotive * Hlectrometer deflection for Latimer Clark’s Standard = 320. ON OHM’S LAW. 61 force in yolts between D and F, 7. e. the wa FE of the formula above; s de- notes the radius in centimetres of the fine wire; the other letters have the same meanings as before) :— R. é. PE. y. s. h<= (1) ...) 244] 114] 023} -44 | -O021 = C 2) ..., 475 | 117] 012] -46 |-dozs | 28 ie y ‘ 320 (3) ...) 027 | 116] 214] 45 |-0070 | 3 668 (4) ...] 081 | 269] 432] -46 |-0070 | js The formula by which the limit to / is calculated is Awr’s' yRD?EE * where Av is the difference between + + and + — balances (see above). In the four experiments discussed, the arrangement was abundantly sufficient to indicate a difference of a millimetre, so that Aw is 75 _* ohm: io Ua ciats 752s! 10%R (PE) A= ene Assuming, then, that the heating- and cooling-effect discussed above may be neglected, the result of the experiments is that h is certainly less than ie In other words, if we have a conductor whose section is a square centimetre, and whose resistance for infinitely small currents is an ohm, its resistance (provided the temperature is kept the same) is not-diminished by so much as the Ti With regard to the heating- and cooling-effect, it must evidently be very small, since it takes place, if at all, in something like the +4, part of a second. It is of course possible that these alternations were at that particular rate for which the two effects would balance each other; but when we consider that the temperatures of the thin wire were very different in the different ex- periments (notably so in (3) and (4) with the iron wire, where the current passing was in one case more than double that in the other), and that the heating- and cooling-effect must depend on the temperature of the wire, while the other is independent of that as well as of the rate of alternation, the pro- bability that any such balancing of the two effects existed at all is reduced to almost nothing. We may therefore look on this experiment as a verification of Ohm’s law to the degree of accuracy indicated above. part when a current of a farad per second passes through it, APPENDIX. While thinking how to repeat Dr. Schuster’s experiments as nearly as was possible without the command of a sine-inductor, the writer of the Report 62 REPORT—1876. was led to try a third experiment in verification of Ohm’s law. If there be a periodic variation of the primary of an induction-coil, the time integral of the electromotive force in the secondary through one complete oscillation will be zero; but if the variation consist of a sharp break, although this law holds, yet the oscillation in the secondary may be divided into two parts, in one of which the maximum intensity is very much greater than in the other. If it be true, then, that a more intense current encounters less resistance than a less intense current, clearly the law above stated can no longer hold; the law has, in fact, been deduced on the supposition that the resistance is independent of the strength of the current. It follows, therefore, that if we send the induction-currents from the secondary of an induction-coil, whose primary is made and broken by a tuning- fork, through a helix of fine wire to make sure of bringing out the effects we are looking for, then the needle of a galvanometer introduced into the secondary will be deflected so as to indicate a current in the direction of the current due to breaking the primary. Certain anomalous, and at first sight contradictory, results led the writer to study the behaviour of a galvanometer under these circumstances. The result was the suggestion of a theory which explained the anomalies com- pletely, and indicated the existence of certain other phenomena which were afterwards observed. é The results are, so far as the writer has been able to learn, ‘ontte new. Although not of sufficient importance in connexion with the present subject to require detailed mention here, yet it was thought best to state the results so far as they bear on the question, reserving a detailed account for publica- tion elsewhere *. It was found that, under the circumstances indicated above, the indication of a galyanometer is a function of the ratio of the strengths of the magnetic field when there is no current and when the currents are passing, and also of the position of equilibrium of the needle when there is no current. _ Theory and observation give alike, among others, the following peculiari- ties :— 1. If the ratio of the magnetic forces due to the currents to that acting on the needle when there is no current does not exceed a certain quantity, then if the position of rest of axis of the needle is inclined at an angle a (< 90°) to the plane of the coil-windings, the effect of the alternating currents is to increase that angle, so that, according as the needle is deflected one way or the other by means of the deflecting magnet, we get opposite effects, The effect is zero when a is zero. 2. If the above-mentioned ratio exceeds a certain value, the position of the needle parallel to the windings (i. e. for a=0) becomes unstable, and there now appear two positions of equilibrium of equal inclination either way to the coil-windings. Either of these the needle will take up and keep if brought there with sufficiently small velocity. The greater the ratio, the more nearly these two positions approach to parallelism with the plane of the coil-windings. The last-mentioned phenomenon was described long ago by Poggendorff, under the name of *‘ doppelsinnige Ablenkung,” and was and has been regarded apparently as an unstable phenomenon. The first-mentioned form of the phenomenon has not, so far as the © or a M=I oD Prare ITI, . Mandible from Nebalia. . Mandible from Pontza. 21. Mandible from Palemon. . Labium, posterior, from Palinurus. I Deutognathe from Cancer, adult. . Deutognathe from Cancer, young.’ . Tritognathe from Cancer, adult. . Tritognathe from Cancer, young. . Tetartognathe, or maxilliped of authors, ee 28. Tetartognathe, or maxilliped, of Amphipod. . Gnathopoda from Cancer, young. . Gnathopoda from Cancer, adult, . Gnathopoda from-Macrura. . Gnathopoda from Squilla. . Gnathopoda from Amphipoda, be ow bO bD NO HO bY HD bo bo $3 GOT Co OT HS COND G9 G9 G2 Go =) Plate IT. 46% Report Brit.Assoc. 1876. Engraved hy WFaithorn 46% Report Brit. Assoc. 1876. Plate I. Engraved by WFuttheoriv. ere oe mes, y ae r] a ON THE CIRCULATION OF UNDERGROUND WATERS, 95 Second Report of the Committee for investigating the circulation of the Underground Waters in the New Red Sandstone and Permian Forma- tions of England, and the quantity and character of the water supplied to various towns and districts from these formations. The Committee consisting of Professor Hutt, Mr. Binney, Rev. H. W. Crosskey, Captain D. Gatton, Professor A. H. Grenn, Professor Harkness, Mr. H. Howeit, Mr. W. Monynevx, Mr. G. H. Morron, Mr. Peneetty, Professor Prestwicn, Mr. J. Puant, Mr. Metiarp Reape, Mr. C. Fox-Srraneways, Mr. W. Wur- TAKER, and Mr. C, E. Br Rance. Drawn up by Mr. Dr Rance (Secretary). Srvc the last Meeting of the Association your Committee have continued to distribute largely the circular forms of inquiry, and a large amount of valu- able information has been obtained, especially as to the deep wells of Liver- pool, Birkenhead, Nottingham, and Birmingham. But in several districts, as in Staffordshire, important information is promised so soon as works now in progress are completed ; and the members of your Committee taking charge of those districts have considered it best to defer making a report until they present you with a final one on their particular areas. . Your Committee, should they be reappointed, have every hope, from promises already received, of completing the trust which you haye given them by the next Meeting of the Association. In the present Report the details of wells in the New Red Sandstone are collected, which yield at Liverpool no less than 7,197,330 gallons daily; at Birkenhead more than 7 millions ; at Coventry, Birmingham, and Leaming- ton 43 millions; at Nottingham nearly 4 million gallons; at Warrington 572,360 gallons; at Stockport 1,073,820 gallons, The largest yield of one individual well is that at Green Lane, Old Swan, near Liverpool, the average daily yield of which in 1875 amounted to 2,533,050 gallons, and the present maximum of which amounts to no less than 3,243,549 gallons pumped up by three engines, one at least of which is always at work, from a depth of 136 feet. In regard to the Liverpool wells, it appears to be established by the obser- vation of Mr. Deacon, the Borough Engineer, to quote the words of his Report, ‘That the water in the public wells is regularly sinking to a lower level, or that if it be maintained at a constant level, the water capable of being pumped is a continually diminishing quantity.” But there is not yet sufficient evi- dence to prove what balance of absolute quantity of water still remains in the sandstones of the area capable of being drawn on by additional wells. Amongst the borings, of which the details will be found in the present Report, is one at Rampside, near Barrow-in-Furness, which reached a depth of no less than 2210 feet from the surface, in a fruitless search for coal. At a depth of 250 feet a spring of water was cut in the Permian Red Sandstone, which yields 13,500 gallons of water daily, flowing out at the top of a one- inch pipe, and rising to a height of 12 feet above the surface of the ground. The rocks beneath the Permian have been proved by this boring to be of Yoredale age, the Coal-measures being absent, as stated would probably be the case by Mr. Aveline and other geologists before the boring was carried out. An interesting feature in this boring is the presence of petroleum-oil in the Yoredale rock near the bottom, which caused the water cut in penetra- ting this sandstone to be much charged with oil. 96 - REPORT—1876, Your Committee would wish to cali attention to the publication, since the last Meeting, of the sixth and final Report of Her Majesty’s Commissioners appointed to inquire into the best means of preventing the pollution of rivers. The volume treats of the Domestic Water Supply of Great Britain, and in it the Commissioners state that the New Red Sandstone Rock constitutes one of the most effective filtering media known ; and being at the same time a powerful destroyer of organic matter, the evidence of previous pollution, in water drawn from deep wells in this rock, may be safely ignored, “ for being a porous and ferruginous rock, it exerts a powerful oxidizing influence upon the dissolved organic matter which percolates through it. To such an extent is this oxidation carried, that in some cases, as in those of the deep-well waters supplying St. Helen’s and Tranmere, every trace of organic matter is converted into innocuous mineral compounds.” The Commissioners further add that, though the quartz sand constituting the bulk of the New Red Sandstone is usually cemented together by carbonate or sulphate of lime, the hardness of the water is generally moderate, and of a nature that can be softened by lime, according to Dr. Clark’s method, and that the ‘“‘ unpolluted waters drawn from deep wells in the New Red Sandstone are almost invariably clear, sparkling, and palatable, and are amongst the best and most wholesome waters for domestic supply in Great Britain. They. con- tain, as a rule, but a moderate amount of saline impurity, and either none or but the merest traces of organic impurity. There is every reason to believe that a vast quantity of hitherto unutilized water of most excellent quality is to be had at moderate expense from this very extensive geological for- mation.” This area is certainly not less than ten thousand square miles in extent in England and Wales, with an average rainfall of 30 inches, of which certainly never less than 10 inches per annum percolates into the ground, which would give an absorption of water amounting to no less than one hundred and forty- three millions three hundred and thirty-six thousand gallons per square mile per annum, which, on an available area of ten thousand square miles, gives an annual absorption of nearly a billion and a half of gallons in England and Wales. How small a proportion the enormous quantities pumped at various stations (as exemplified in this and the previous Report) bear to the available resources, will be at once apparent. The abundant balance left will, we trust, ere long be made available for those towns and country populations in the Midland Counties now suffering all the ills so prolifically springing from a polluted water supply. Mipianp Counrres. Name of Member of Committee asking for information, Rev. Henry W. Crosskey. Name of Individual or Company applied to :— Waterworks, Coventry. 1. One 196 ft. deep, one 75 ft. deep, and one 300 feet from surface. 2. 256 ft. 3. 10 ft., 4 ft. diameter; 290 feet, from 2 ft.to6 in. 4. 14 feet; difference 12 hours. 5, 800,000. 6. Yes, diminished slightly. 7. Yes,ina few hours. 8. No. 9. Red Sandstone and clay. 13. No. 14. Not aware of any except at Leamine- ton, 15. No. Birmingham Corporation. 1. Aston, juzta Birmingham. 2. 295 ft. 3. 120 ft., diameter 10 ft.; 407 ft., 18 in. bore-hole, 4. Overflows 10 ft. above surface, 100 ft.; pump night and day. 5. 3 million gallons. 6. Not observed to have altered. 7. Not observed. ON THE CIRCULATION OF UNDERGROUND WATERS. 97 Grains per gallon. yi Wa LO VAM SOG SE cctbx surveys & Sistem Glaeonals: Ge oleaa eile 12:88 Volatile combustible matter ...........005 0°84 ° MlOLMAGOMsHON 5) deere tod ete eee ee eal 0°91 INUIT OE CGT Uv ath Cie ace putamen ee Berar 0-00 Hardness before boiling ...... 9°°3 9. 28 ft.; iron tube through top soil and drift-gravel, the rest all sandstone with marl and partings and some fine conglomerate ; finish of bere-hole in 25 ft. thick of marl. 10. Yes. ii. Yes. 12. No. 13, No. 14. None nearer than Cannock. 15. No. . Name of Member of Committee asking for information, T. Mellard Reade. Name of Individual or Company applied to :— Leamington Local Board, per Mr. Bright. 1. North-east portion of Leamington. 2. 205ft. 3. 80 ft. deep, 8 ft. diameter ; 234 ft. deep, 18 in. diameter. 4. Normal level 20 ft. below surface. 5. 750,000 galls. ‘ie day. 6. Works not yet completed.. 7. Top of water is 26 ft. above river Leam. 8. Analysis attached; water remarkably pure and soft, whereas sur- face-wells contain very hard water. Analysis of water from the new bore-hole, by Dr. Horace Swete, taken from a depth of 200 ft. from surface. Water very clear, almost as clear as distilled water —the smallest point being easily read at a depth of 2 ft. Temperature at well, 50° Fahrenheit ; requires no filtration. : Grains per gallon. Motel solids: *¥iahess see 3. < Joop ceo aoe Asomadt : 20:0 (SYSLOTIG CII Seis 7.1 ORION g ere oe REARS Recs 13 Sulphates—very sparingly. Nitrate—a.trace. Faint trace of iron. Temporary hardness .......... 55 Permanent SARUM GS Sib a oiele 6-5 12:0 : oy Parts per million, Free ammonia .......... ce 8: + SI yale ee ec Allbumenoidal- ammonia . .,:,.,<,.,6,s0.0.8 se hee «c's «ye “020 This water is an extremely pure specimen, even for a deep well, and requires no filtration. It contains less than one tenth of. the amount of organic matter than the present town supply, and is not only.a softer water for domestic purposes, but the deposition of carbonates causing. incrustation in boilers is considerably less in quantity. : 7 February 2nd, 1875.’ Horace Swetr, M.D., Analyst. 9. Map of strata previously sent, consisting of sandstone of various thickness divided by marls. 10. Yes. 11. Yes. 12. Not within a mile, where one is known south of Borough, and another two miles west. 13. No. 14. Yes, in the valley half a mile south. 15. Yes ; the first experimental boring was discontinued in consequence of finding, under the saliferous marls, very salt water, one layer of this marl being more than 100 ft. thick. ae _ Name of Member of Committee asking for information, C. Tylden Wright. _ Name of Individual or Company applied to :— The Manager, Nottingham Waterworks. ; 1. Bestwood pumping Station, near Nottingham. 3. Depth of shaft 64 yards; size 16 ft.x 10. ft.; two tunnels are driven out from the bottom about 50 yards, 5. Maximum quantity pumped for 24 hours 3,772,800 galls. ; minimum quantity 8,456,000 galls. 9. Pebble beds of the New Red Sandstone. 1. Worksop. 3. Bore-hole 4 inches in diameter, depth 360 ft. 5. Pumping in 1875, 40 gallons per minute. rf 1876. i 98 . -REPoRT—13876. Shire Oaks Colliery, Worksop. 1, Shire Oaks Colliery, Worksop. 3. 3 shafts, 12 ft, diameter. Galls. Depth. Yellow limestone .........000 . 400 17 yds. 5. Water per hour.. 4 White Fie crane OS Got . 3890 25 5 Dark a Sokoogdeaoarne 50 «38 «SC» 9. Permian marls and magnesian limestones; the principal feeder of water occurs in a soft coarse sandstone lying on the bottom of the magnesian limestone. Papplewick Colliery, through Mr. W. F. Webb, of Newstead Abbey. 1. Papplewick, near Annesley. 3. 335 yards shaft. 5. At 3 yds. a little water, at 44 yds. 7 in. 18 galls. per minute tubbed out, at 60 yds. 50 galls.; below this only an increase of 5 or 6 galls, 9. Drift. yds. ft. Magnesian limestone ....... es eee renee erenerenes a 69 1 Black shale (coal-measures).........+0005 Scoot dg 30 22 MEV tic ODM rete iapstalatist iarens cfaletetnietcvelal sjevel'g,sleleke ‘ahaa yy 4a 0 Plant impressions .....+.0-.++e0 ie chalet ama cads » 330 O 13. At 126 yds. 2 ft. a small salt spring, 5 galls. per minute. Mr. Robert Stevenson, through Mr. W. F. Webb, of Newstead Abbey. 1. Newstead Colliery. 3. Bore-hole at Colliery gives off 25-44 galls, of water per minute. New Red Sandstone, near outcrop of the formation. Mr. W. F. Webb, Newstead Abbey. 1, Blidworth. yds. 3. Depth of well at the Hut.......... 42) i 4 Gurnall’s .......- 3 es “th i i sy. NGBEN ANIA. 5 on aie s 6 [ 2 Cae Besstor’s. 3 ¢ Stone fragments D TPES ea Ole ea | and gravel. or Town-pump well ........ Gar eel 8 rs School well......-..+.04- he) f Well at C. Clarkes’ ...... 507 65 5 Waters’..... +0 .. 40 is "9 Hutchinson’s .... 40 * 49 Wilson’s ......0s 3 - = Herbert's ois... G ak aS LOWE Olli tise disidelat asic 3 f ‘In Sandstone, ” Well atPlaiis.. cc... ek 3 - + G. Johnson’s...... 27 x Fy IOUS Eis sebelets ste 26 5. » Mount Pleasant .. 31 J - ~ Cresswell’s,,..... 28 py) New ane stoma. 3 Lucas Cross Lane., 384 Blidworth Bottom... 8 oh Long Dale........ 26 + Wells at Fishpool ........ 6-25 9. Drift-gravel and clay; red sandstone; the water occurs immediately after passing through a seam of conglomerate 3 inches thick. At Fishpool is a spring, which, after 20 years’ cessation, commenced running during the dry summer of 1868, and then stopped, but recommenced in the summer of 1874, 10, Yes, which supply the shallower of the above wells. Name of Member of Committee asking for information, W. Whitaker. Name of Individual or Company applied to :— Staffordshire Potteries Waterworks, Hanley. 1, North Staffordshire, 4 miles S.E. from railway-station, Stoke-upon-Trent (1 in ” 9) ” 9 ON THE CIRCULATION OF UNDERGROUND WATERS. 99 Ordnance sheet, 72N.W.). 2. 615ft. 3. Shaft 145 ft. deep, 12 ft. diameter; bore-hole 500 ft. deep, 24 in. diameter. 4. The level of water in this case is kept down nearly to bottom of shaft, but the water has been found to fill 900 cub. yards of standage drift and rise about 20 ft. up shaft in 24 hours. 5. 900,000 galls. 6. The seasons affect this shaft very little ; the feeders have been permanent during the past 5 years, but Jess than when the shaft was put down (bore-hole in hand at present). 7. No. 8. Water of good quality; about 9° hardness. 9. New Red Sandstone (with band of marl of considerable thickness), cover about 20 ft. Ifa section of the shaft and bore-hole would be of service I should be glad to supply the same. 10. About 1 mile N.E. there are several copious springs, and apparently quite unaffected by the above sinking. 11. No surface-spring near well. 12. There are several faults in the im- mediate locality. A large fault running about V.Z., and about 1 mile north of this shaft, supposed to be the southern limuts of the N.-Staffordshire coal-field ; but borings just completed to the south have proved coal at a depth of 265 yards, 13. None. 14. None to my knowledge. 15. The above well is the only one in the neighbourhood sunk for the purposes of water supply. Messrs. Mather and Platt. 1. Messrs. Lonsdale and Adshead, Macclesfield. 3. 12-inch bore, 94 ft, deep. 5. 66,240 galls. LANCASHIRE AND CHESHIRE, Name of Member of Committee asking for information, G. H. Morton, Name of Individual or Company applied to :— Mr. George F. Deacon, C.E., Municipal Offices, Dale Street. 1. Litherland Road, Bootle, near Liverpool. 2. 60 feet. 3. Depth of shaft 108 ft.; oval, 12’0"x9 0"*, 4, Pumping continuously, except when stopped for repairs. During a stoppage from 80th Jan. to Feb. 18, 1876, the water rose 11 ft. above Ord. datum, or 56 ft. above the bottom of the well. 5. Average for 1875, 1,399,791 galls.; present maximum 1,433,720 galls. 6. See reports herewith. 7. See No. 4. Effect of local rains not traced. 8. Copy of Analyst’s last report. Pela : Nitrogen Tet soli : - as ota. Organic | Organic : Htnite F F Total Suspended ied Carbon. | Nitrogen. oe Rees et PEELS Hardness. | Matter. Solution. Nitrates. er. er. er. er. er. er. er. Clear 366 181 055 002 345 401 36 234 and bright. 9. F 2; drift about 12 ft. (pebble beds and “Lower soft Bunter Sandstone”). 10. No. 11. The well is lined with brickwork in cement down to the hard rock. 12. Yes. 13. No. 14. No. 1. Green Lane, Old Swan, near Liverpool. 2, 156 ft, 3. Shaft 10 ft. diam., depth 185 ft. ; 1 bore-hole 9 in. diam. for 173 ft.9 in., and 6 in. diam. for 25 ft. 10 in. from bottom of shaft ; 1 bore-hole 24 in. diam. for 12 ft., and 18 in. diam, for 298 ft. 4. There are 3 engines, and the whole are never stopped at one time. . Average for 1875, 2,533,050 galls, ; present maximum 3,243,549 galls. 6. It has diminished (see reports herewith), 7. Effect of local rains has never been directly traced. * There are altogether about 16 bore-holes in the lodges connected with this well. They were sunk many years ago, and records have not been preserved of the details, The cae bore-hole is 6 in. diameter at the top, and its depth from the surface is about OU Tt, uw 2 100 REPORT—1876. 8. Copy of Analyst’s last report. an Nitrogen ripe, soli : . as ota! Organic Organic : Phas : . Total Suspended MiBHPE Carbon. | Nitrogen. ae Mireniies mere Chlorine. Hardness. Matter. Solution. Nitrates. r. is er. er. er. er. er, 5 Clear 28 085 06 003 “345 408 2°72 20 and bright i) 9. Rock F 2 (“ Bunter Pebble-beds”) ; cover of drift and clay 15 to 20 ft. 10. No. 11. There are none. 12, Yes. 13. No. 14. No. 15. No. 1. Dudlow Lane, Wavertree, near Liverpool. 2. 200 ft. 3. Depth of well 247 ft.; shaft oval, 12’ 0" x9' 0"; depth from surface to bottom of bore-hole 489 ft.; diameter of bore-hole 18 in. 4. Pumping continuously except when stopped for repairs. Stoppage from 5th to 30th Nov. 1875, water rose to 95 ft. from bottom of well. 5, Average for 1875, 1,103,307 galls.; present maximum 1,329,107 galls. 6. See printed reports herewith. 7. See No. 4; effect of local rains not directly traced. 8. Copy of Analyst’s last report. Pan Nitrogen f : son Organic | Organic - {88 Total + Total Suspended Matter 4° Ammonia.| Nitrites | combined | Chlorine. P aa Carbon. | Nitrogen. Sl Nitrogen. Hardness. | Matter. Solution. Nitrates. er. gr. er. er. er. é er. 6 ‘Clear 18 “C91 031 003 368 402 2°87 8 and bright. 9. F 2 (“Bunter Pebble-beds”): rock nearly to the surface, only thin cover of drift. 10. No. 11. There are none. 12. No. 13. No. 14. No. 1, Lodge Lane, Toxteth Park, Liverpool. 2. 186 feet. 3. Depth of shaft 210 ft.; oval, 12'0"x10' 0"; depth from surface to bottom of bore-hole 454 ft.; diameter of bore-hole 6” for 189 ft., 4" for 55 ft. ; 4. Pumping continuously, except when stopped for repairs. In a stoppage from the 3rd to the 13th April the water rose to 50 ft. 6 in. from bottom of well. 5. Average for 1875, 821,182 galls. ; present maximum 876,428 galls. 6, See printed reports herewith. 7. See No. 4; effect of local rains not traced. 8. Copy of Analyst’s last report. teat Nitrogen BO Organic Organic . Hiss Total . Total Suspended a ee Carbon. | Nitrogen. Ammonia. | N: apes Nae Chlorine. Hardness. Mabey. Solution. Nitrates. er. r. e: or. gr. er. er. a Clear 35 051 ‘O11 003 ‘276 29 2°72 233 and | | bright. 9, F 2 (“ Bunter Pebble-beds”). C over of drift about 20 ft. 10. No. 11. There arenone, 12. No. 13. No. 14: No. Messrs. Mather and Platt. 1. Messrs. Roberts and Robinson, Liverpool. 3. 18-in. bore, 463 ft. d ‘ 5. 1,440,000 galls. 9. New Red Sandstone he, rep ON THE CIRGULATION OF UNDERGROUND WATERS, 101 _ Name of Member of Committee asking for information, T. Mellard Reade, _ Name of Individual or Company applied to :— Ormskirk Local Board. j : 1. The wellis situate within a short distance from-the town of Ormskirk, on the N.E. side, and near to Bath Wood. 2. 129-1 ft. above Ordnance datum. 3. From ‘surface to bottom of well 60 ft. deep, 7 ft. diameter. There is no bore-hole in the well. 4. Before pumping the water rises to the surface of well; after pumping the water stands 2 ft. deep at bottom of well. Ordinary level restored in 2 hours after pumping. 5. 232,000 galls. 6. The water-level varies slightly in summer and winter, but has not diminished during the last 10 years, 7. The ordinary level is affected by local rains within 24 hours afterwards. 8. Analysis of the Ormskirk water by Dr. Brett, of Liverpool. This water, when left to stand, is perfectly colour- less, devoid of odour, and pleasant to the taste; its composition is as follows, the amount of ingredients being calculated to the imperial gallon :— rains, Chloride of sodium, or common salt.............. 73-90 Sulphate of lime, or gypsum ........sseeeeeeeaes 1:92 Carbonate of lime..............085 Brea cekarsLasatets «ake 1:04 @arbonate of maonesia i/.55 ce ols @ a0 c8e sis aateres 0:40 Oxide of iron with a little silica...............005 Q-12 Total .... 6-68 9, The strata are, first marl 11 ft., sand 7 ft., the remainder is New Red Sandstone. 10. Yes. 11. No. 12. Yes, especially a very large fault on the west side of well. 13. No. 14. No. 15. No. Name of Member of Committee asking for information, George H. Morton. Name of Individual or Company applied to :— St. Helen’s Waterworks. 1. Eccleston Hill, adjoining turnpike, and at the sandstone-quarry, marked 260 ft. above Ordnance datum (see Ordnance sheets). 2. 260 ft. 3. Depth 70 yards, diameter 10 ft.; depth from surface to bottom of bore-hole 388 ft. 4. As the umps never cease puoning it is difficult to say, meanwhile the water is practically ept down to one level. 5. 640,000 galls. per day of 24 hours. 6. The yield varies at different seasons, but to what extent it is difficult to say : the water has diminished during the past 10 years. 7. Yes; but after a dry summer it takes 8 or 10 weeks before the 1 or 2 extra hours out of the 24 can be resumed by the extra engine. The water-level in wells stands below adjoining streams, 8. We have no analysis; the water is of very excellent quality. 9. No drift. The wells or shafts are sunk in the New Red Sandstone formation, through the middle or pebble-beds division of the Bunter, and to a depth from the surface of about 18 ft. into the lower division, 70 yards in all. Thus, “WTI After boring 60 ft. deep, no water-yielding strata found — that is, 60 ft. below bottom of well, and in lower formation. 10. No drift. 11. No. 12. Cannot speak of these (if any) with certainty; none proved, 13. No. 14, No. 15. No, 102 REPORT—1876. Name of Member of Committee asking for information, Mr. T. Mellard Reade. Name of Individual or Company applied to :— Messrs. Mather and Platt. 1. Seedley, near Manchester. 3. 102’87"; 382’x18", 354’x 18", 167’x 18", 5. 750,000 galls. from the three holes*. 9, Red Sandstone with bands of raddle. 1, Chester Street, Oxford Street, Manchester, 3. 70'x4'; 536'x15". 5. 570,000 galls, 1. Messrs. Bayley and Craven, Manchester. 3. 18 in. diameter, 454 ft. in depth. 5, 648,000 galls, 9. New Red Sandstone. 1. Messrs. Aitken Brothers, Manchester. 3. 18-in. bore, depth 378 ft. 5. 800,000 galls. 9. New Red Sandstone. 1. Messrs. William Sumner, Manchester. 3. Bore 12 in. diameter, 189 ft. in depth. 5, 46,080 galls, 9. New Red Sandstone. 1. Messrs. Rylands and Sons, Manchester. 3. 12-in. bore, 312 ft. in depth. 5. 90,720 galls. 9. New Red Sandstone. 1. Messrs. B, D. Brookes, Manchester. 3. 12-inch bore, 259 ft. in depth. 5, 86,400 galls. 9. New Red Sandstone. 1. London and Manchester Plate Glass Company, St. Helen’s. 3. 9-inch bore, depth 348 ft. 5. 48,000 galls. 9. New Red Sandstone. 1. Messrs. A. and J. Stott, Flixton, Manchester. 3, 12-inch bore, 284 ft. in depth. 5, 317,520 galis,” 9. New Red Sandstone. 1. Messrs. Chadwick and Taylor, Higher Broughton, Manchester. 3. 75'x 10’; 671'x 15", 5. 800,000. 9, See Section. 1. The Convalescent Hospital, Cheadle. 3. 12 in. diameter, 146 ft. in depth. 5. 55,200 galls. 9. New Red Sandstone. 1. Messrs. Ermen and Roby, Patricroft. 3. 18 in. diameter, 315 ft. deep. 5, 100,800 galls. 9, New Red Sandstone. 1, Salford Ironworks, Manchester. 3. 18 in. diameter, 212 ft. deep. 5. 50,000 galls. 9. New Red Sandstone. 1. Messrs. Thoms, Chadwick, Salford. 3. 12-inch bore, 432 ft. deep. 5. 50,000 galls. 9, New Red Sandstone. 1. Messrs. J. J. M. Worrall, Salford. 3, 18 in. diameter, depth 400 ft. 5. 480,000 galls. 9, New Red Sandstone. 1. Messrs. Roberts, Dale & Co., Cornbrook. 3. 9-inch bore, 178 ft. deep, 5, 30,000 galls, 9. New Red Sandstone. Name of Member of Committee asking for information, George H. Morton, Name of Individual or Company applied to :— Birkenhead Commissioners, per Mr. W. T. Callow, Water Engineer. 1. Flaybrick well, Birkenhead. 2. 176 ft. 3. Shaft 205 ft., 16 ft.x8 ft.; the bore-hole $22 ft., 18 in. wide; the bore-hole 773 ft.,18 in., Aug. 11, 1876t. 4. 156 ft. from the surface. 5. Usually 13 million galls. in 13 hours; 2 or 3 mil- lions have sometimes been obtained by continuous pumping for 24 hours. 6. No. 7. A little additional in wet seasons, 8. Result of analysis expressed in parts per 100,000 :— * The three bore-holes are all in the same well, and the water rises into well, and is pumped up to the surface. t In progress and will probably be 800 ft.; the deepest in the neighbourhood of Liverpoul. ON THE CIRCULATION OF UNDERGROUND WATERS. 103 Total solid matter in solution........cseeeeeeee 1 Organic carbon. .....seereereeeeeeene Bes eheeze . 074 Organic nitrogen ....... sees eee ee bi veeeee's .. 066 PATIOS 4), siefe) «! oiovelesd is 8) shy altel aad sYotedeleiei sal aie 002 Nitrogen as nitrites and nitrates ....seseeseeee 340 Total combined nitrogen..... Sic aiegee aiakaimleleiegsisin © 413 Ghiorine. Vkjswen aes Eats cieaett ion debe east e bie, Od Hetardnessy,totalatrsre.: shows slooisseio ets wake 43° Suspended matter clear and bright. 9. No drift; base of Keuper Sandstone, upper soft Bunter Sandstone, Pebble-beds. 10. No drift. 11. There are none. 12. There is a fault close to the well, with a throw of about 70 ft. 13. No. 14. No. 15, No. George H. Morton, Birkenhead Commissioners, per Mr. W. T. Callow. 1. Spring Hill, Claughton, Birkenhead. 2. 125 ft. 3. Shaft 95 ft. deep (2 shafts 7 ft. diameter); bore-hole 395 ft. from surface. 4. 115 ft. from the surface. 5. 5 million galls. per week are obtained by pumping night and day. 6. Does not vary ; has diminished 20 ft. since 1858, 7. No. 8. Result of analysis expressed in parts per 100,000:— Fs Total solid matter in solution........ 21 Organic carbon.......++ eee ee eeene ‘110 Organic nitrogen ....isssseeveveees 062 AMMONIG 2424 25i 352 eka ee see es 002 Nitrogen as nitrites and nitrates .... 253 Total combined nitrogen.,........5. 317 CHT Orie We) aie sw clererabr te rhb oinist ante . dl Total hardness.........+.. 104° Suspended matter clear and bright. 9. No drift; base of Keuper Sandstone; Upper soft Bunter Sandstone. 10. No drift. 11. There are none. 12. No, not very near. 13. No. 14. No. 15. No. Wirrell Waterworks Company, Prenton, Birkenhead. 1. Prenton valley, 3 miles S.W. of Birkenhead. 2. 80 ft. 3. 90 ft., diameter about 12 ft., bore 295 ft., diameter 18 in. 4. 68 ft., fills rapidly pumping. 5. About 2,000,000 galls. 6. No. 7. No. 8. Very pure and AE 9. Boulder- clay about 10 ft., the rest Upper Bunter, but the bore-hole chiefly in the pebble- beds. 10. No. 12. Only of the ordinary kind. 13. No. 14. No. No 1. Wirrell Waterworks, Oxton, near Birkenhead. 3. 22' 6"x4', 369’x 15". 5. 750,000 galls. 9. White and Red Sandstone, chiefly red. ” Tranmere’ Local Board, per Mr. W. A. Richardson, C.E. 1, Happy Valley, western side of the township of Tranmere. 2. 89 ft. 15 in., 3. 128 te 9 ft. diameter of shaft; bore-hole 250 ft., 9, 6, 4 in., and 1380 ft. 15 in. from bottom of well ; 378 and 318 ft. from surface. 4, 78 ft.8 in. below surface. 5. 720,000 galls. 6. No; it has diminished 9 ft. 6in, in 10 years, but only 2 ft. 1 in. during the last 8 years. 7. No; 28 ft. 2 in. above sea-level. 8, Clear, pure, and tasteless ; about 8°75 degrees of hardness; analysis :— Grains per gall. Free @MMONIA. ..... cee eee eee eee wnfaitee nl O:0085 Ammonia derived from organic matter.......... 00018 Organic matter, exclusive of nitrogen .......... 0:0180 Carbonate of lime and magnesia......... ConA Mae 5:8770 Carbonate of SOda. ice ee. ele ewe ds eee neces 1:6960 Sulphate of lime ....cssseesee cece seen serene 3'5720 NItMaLS TOR MAGN OSTA ccansyeiEh anhleidlasvole @ bieinjeseal esa 0:9640 Chloride of sodium ..... said A Grevetaperelatbs diel rayast . 938440 Silicie acid, a mere trace. 159763 9. 15 ft. of drift; no clay: Upper soft Bunter Sandstone, 10. No, 11. There 104 : REPORT—1876. ‘are none. 12. One about 150 yards to the east of well. 13. No. 14. No. 15. No. ; ; Wallasey Local Board. 1. Township of Seacombe, ‘parish of Wallasey, county of Chester, between the Great Float, Birkenhead, and River Mersey. 2. About 20 ft. 3. 90 ft.; 246 ft., 12in. and 8 in. diameters. 4. If atrest many hours, about 16 ft. before, and after pumping about’50 ft. from surface. 5. Present machinery has pumped about q million galls. per diem; it is estimated that at least twice can be by addi- tional boring, &c. (in hand). 6. Does not vary much; diminution, during time named, due to increased pumping. Cannot say otherwise, as engine cannot be stopped long enough to test the question. 7. Not perceptibly. Level when at rest would stand a few feet above mean high-water level. 8. Have not an analysis at hand ; water about 6° of hardness (Clark’s test); water very good and clear.’ 9. Section sent herewith :— ft. Redtmatlam nei tedster neces ae to 78 ANG tarid atiarl {see ytebetets aie ete oe emer Mar luttess | SEA Socom tes seem tek oe ee » 93 Claycandisanda sw. cts. crciseecise cei fies )) (W hike role cee ii sifion sti ont haces bite », 108 EGE MOCKED Mosse cicioacie @ oie fl. ieee doeras », 164 Gepgeraele |... > ss bv se ici 53 op comme eee A dled} lian dhre drach (Neri. yc. cicccvets. debe is) Sole rod. rock pa5.ccwes Gauss otiasiow ee oe » 246 Bottom of bore-hole..........0+++05 at 500 11. Yes. 12. It is believed. so. 13. No. 14. Not aware of any. 15. Not aware of any deep ones. Mr. William Inman, J.P. 1. Upton, 4 miles W. of Birkenhead. 2. About 100 ft. 3. 173 ft., diameter about 8 ft.; bore 278 ft. diameter, and 6 in. wide. 4. About 100 ft. above Ord- nance datum. 5. Not known. 6. Not known. 7. Not known. 8. Very good. 9. Allred marl of Keuper. 10.No, 12. One about a mile E. of the well, which brings the Upper Bunter and red marl in contact. 14. No. Name of Member of Committee asking for information, T. Mellard Reade. Name of Individual or Company applied to:— Messrs. N. Mathieson & Co., Widnes. . 1. Our own, No. 1 well, at N.E. end of works, Widnes. 2. 10 ft. 3. 4 ft. 6 in, diameter x 30 ft. deep ; bore-hole 366 ft. from surface, 6 in. diameter. Before, about 6 ft. from surface; after 5 hours, about 25 ft. from surface. 5. About 2000 galls. per day of 12 hours. 6. Not being used. No means of testing. 7. No. 8. No analysis taken ; moderately good. fitaeeame Or Marshicl by. eect haan dene alee 7 0 Quicksand arena: Ohl ey. Bee 23.20 Browatelay coadecaink Sh Se cae aes 10 0 Quicksand: skereenectsknpre. in sei 6 0 SOIL CLOT=Cl aye cets srcva'e sie sipie's, e's ce Siese's 90 10 RedmroCk mewn ent Ae neve smart 275 2 10. Little, from quicksands. 11. Not entirely. 12. Boring inthe fault. 13. No. 14. No. 15. None. Messrs. Sullivan & Co., British Alkali Works, Widnes. 1. We have two wells, Nos. 1 and 2, at these works; they are about 500 yards apart, and each about 300 yards from the River Mersey. 2. No. 1 well is about 25 ft., and No. 2 ‘well about 15 ft. above the mean sea-level. 3. No. 1 well, fora depth of 27 ft. from the surface is 6 ft. diameter, for a further depth of 31 ft. is 5 ft. diameter, equal 58 ft. total depth of well from surface; the bore-hole is 396 ft. deep from surface x 4 in. diameter. No. 2 well, fora depth of 88 ft. from the sur- ON THE CIRCULATION OF UNDERGROUND WATERS. 105 face is 10 ft. diameter, for a further depth of 22 ft. is 8 ft. diameter, equal to 60 ft. total depth from surface; the bore-hole is 409 ft. deep from surface x 14 in. dia- meter. 4. No. 1 well: water stands 10 ft. from surface before pumping, and takes 4 to 5 hours to rise to the same level again after pumping. No. 2 well: water stands 6 it. from surface before pumping and takes 1 to 2 hours to rise to the same level again after pumping. 5. No. 1 well about 70,000 galls. per 12 hours: No. 2 well about 300,000 galls. per 12 hours. 6. At No. 1 well the yield is less during the summer months than the winter months, and the yield is much less all the year round than it was when the well was first sunk some 7 years ago. No 2 well has only been finished some six months; no variation in the yield has yet been perceived. 7. Not when the water from the quicksand is kept out of the well. In No. 1 well the water-level is about 15 ft., and in No. 2 well about 9 ft. above the mean water-level of the River Mersey, which is the nearest stream. 8. The waters from both wells yield about 24 grains of solid matter per gallon when evaporated down; chiefly salts of calcium. 9. No, 1 well: 2 ft. of soil, 36 ft. of strong brown clay, 17 ft. of quicksand, 2 ft. 9 in. of sand and pebbles, 61 ft. of strong brown clay, 5 ft. of quicksand and pebbles; remainder Red Sand- stone. No. 2 well: 2 ft. of soil, 28 ft. of strong brown clay, 21 ft. of quicksand, 61 ft. of soft clay; remainder Red Sandstone. 10. No; the quicksands passed through of course yield water. 11. Yes; the water from quicksands is kept out, but can be turned in at pleasure. 12. No. 13. No. 14. No. 15. We are not aware of any. The Sankey White Lead Company. 1. On the works of the Sankey White Lead Company Limited, Sankey Bridge, near Warrington. 2, About 25 ft.? 3, 33 ft. 4 in. from surface to bottom of well, 5 ft. 6 in. diameter; 100 ft. from surface to bottom of bore, 8 in. diameter. 4. 3 ft. 6 in. from surface, height to which the water rises ; rose 23 ft. 4 in. in 4 hours. 5. 40 galls. per minute. 6. No perceptible variation; only at work from 5 to 6 years. 7. No observations. 8. No accurate analysis. 9. No rock was met with. Sec- tion as follows :— ft. in ‘Still ig SE GoGo aC re reo eG Sand and gravel .............. 6 6} Wet. Clay with boulders..... veeeees 45 O Absolutely dry. Sand and gravel ............., 2 0 Spring of 15 galls, per minute. Olnyias Above: to. .6k os lees on 25 0 Sand and gravel ............. » 6 O A little increase of water; drift coal. Bore ends in a bed of clean gravel, ; : : ; about 3 ft. thick; the last 15 ft. Clay with thin bands of gravel., 15 0 increased supply to 40 gails. per minute. 100 0 11. All surface-springs kept out. 12. We know of none. 13. No. 14. Not very near. 15. In Warrington bores have been abandoned from this cause. Messrs. Mather and Platt. _ 1, Warrington Wire Company, Warrington. 3. 18-inch bore, 212 ft, deep. 5. 63,360 galls. 9. New Red Sandstone. 1, Messrs. Roberts, Dale and Co., Warrington, 3. 9-inch bore, 225 ft. in depth. 5. 28,000 galls. 9. New Red Sandstone. 1. Messrs. Jas. Owen and Co., Winwick, Warrington. 3, 18 in. diameter, 212 ft. deep. 5, 461,000 galls. 9. New Red Sandstone. Wm. Wood-Blake, Esq., Warrington House, Northwich, Cheshire. 1. Alsager boring, within 300 yards of Alsager Railway Station. 2. 310 ft. 3. Tapped water at a depth of 553 ft. in a 3-inch bore-hole. 4. The water rises to the surface, supplying first a 4-inch bore, then a 5-inch bore at the top; when a 38-inch iron tube is screwed on the 5-inch tube, the water rises to 10 or 12 ft. above the surface. 8. Has been analyzed, and is very pure and soft, and suitable for brew- 106 REPORT—1876. ing purposes. 9. Passed through red marl and grey rock, with thin bed of gypsum, to the red sandstone rock, when the water was met with; continued the boring in the red sandstone toa depth of nearly 1000 ft., but the water was not increased thereby. 10. No. 11. This is a report of boring operations. 12. Within 1 mile. 13, No. 14. Within 2 miles. 15. No. Within 4 a mile of the above boring there is a large mere, called “ Alsager Mere,” 11 acres in extent, with neither an inlet or outlet on the surface, the water of which is very clear and pure. This lake ebbs and flows, rising sometimes even in very dry seasons. Messrs. Mather and Platt. 1. Stockport Waterworks, Wilmston. 3. 12-inch bore, 170 ft. deep. 5. 54,700 galls. 9. New Red Sandstone. 1. Messrs. Charles Marsland, Stockport. 3. 12-inch bore, 182 ft. deep. 5. 30,560 galls. 9. New Red Sandstone. 1. Messrs. R. Sykes and Co., Stockport. "3, 18 in. diameter, 42 4ft. in depth. 5. 806,400 galls. 1. Messrs. J. E. & W. Christy, Stockport. 3. Diameter 12 in., depth 228 ft, 5, 8,200 galls. 9. New Red Sandstone. 1. Messrs. 8S. & T. Carrington, Stockport, 3. Diameter of bore 12 in., depth 190 ft. 5. 50,000. 8. New Red Sandstone. 1. Messrs. Robert Orme, Stockport. 3. 12 inches diameter of bore, depth 192 ft. 5. 24,960 galls. 1. Messrs. Bayley & Co., Stockport. 3. 18-inch hore, 274 ft. deep. 5. 30,000 galls. 9, New Red Sandstone. Name of Member of Committee asking for information, C. E. De Rance, through Mr. W. 8. Aveline. Name of Individual or Company applied to :— John Vivian, C.E., for the Diamond Boring Company, Furness District. 1. Rampside, near Barrow-in-Furness. 2. 25 ft. 3. 8 in. hole at surface and 3 in. at bottom; 2,210ft.deep. 4. Water cut at 250 ft. from surface, and will rise about 12 ft. above surface in an inch pipe. 5. 13,500 galls. flowing out of hole daily. 6. Always running about the same. quantity for the past 4 years. 7. A beck runs within 5 ft. of hole, but at 5 ft. lower level than top of hole. 8. Peculiar water was cut in the petroleum-bearing sandstone, but it only flowed from that place for a short time. 9. Water was cut in the New Red Sandstone; drift about 100 ft. thick, consisting of gravel, sand, boulder-clay and cobbles. 10. No; but a little water was found on top of rock. 11. Tubed out ofhole, 13. Brackish water impregnated with petroleum-oil. 14. None. YORKSHIRE. Messrs. Mather and Platt. 1. Messrs, Boleckow Vaughan, Middlesboro’. 3. 18 in. diameter, 1152 ft. deep. 5. 806,400 galls. 9. New ‘Red Sandstone. See section of upper portion, previ- ously published in last report. Name of Member of Committee asking for information, C. Fox-Strangways. Name of Individual or Company applied to :— Messrs. Steward and Sons.* 1. Messrs. Steward & Sons, Comb Works, Walmgate Bar, York. 2. About 50 ft. 3. 8 yards to bottom of shaft, 46 yards to bottom of first bore-hole, 129 yards to bottom of second. 4. Water stands at about 22 to 23 ft. from surface. 5. 500 galls. per minute from 3 bore-holes. * The present owners of these wells do not appear to know much about them; there- fore I have filled in the form from information previously obtained, and from my own personal knowledge of the locality.—C. F.-8. ON THE CIRCULATION OF UNDERGROUND WATERS, 107 yards. 9. Clay and stones” .i....:.a-. © San A i itaois lca the mhiacineotten 20 Fine sandstone .....+eeeeeees 18 46 The other bore-hole went to a depth of 129 yards, 10, Probably. 12. The geology of the solid strata around York is too much obscured by drift to be sure on this point, 13. No. 14. No, 15. No. Rey. R. D. Owen. 1. In the centre of St. James’s Square, Borobridge. 2. I believe about 30 ft. 3. 256 ft., diameter 4 in. bore-hole. 4. Before 17 ft; after 36 hours pumping a reduction of 2 inches in the bore-pipe. 5. Number of gallons would depend on the kind of pump used. Supply of water is supposed to be unlimited. 6. The pump above is not yet in full work; wells in this neighbourhood vary very little at different seasons of year. 7. Surface-water cut off todepth of 158 ft. from top by iron (30 ft. 6 in.) and copper (158 ft.) pipes. 8. Vide analysis already sent to you. 9. Soft red sand with boulders in it 28 ft. thick ; remainder New Red Sandstone, with about 4 layers of red marl 3 to 4 in. thick. 10. Yes. 11. Yes. 12. No. 13. No. 14. No. 15. No. Messrs. Brett, Sparringate, York. 1.Myown. 2. 18ft.* 3. 80 ft. 4. 6 ft. from surface. 5. Constant flow 14-inch pipe. 6. Not more than 2 ft. at any time. 7. Not at all; not any communica- tion. 8. Much peculiarity; analysis enclosed. 9. Clay, sand, white sand, at 70 ft., at which depth a piece of oak was pulled up in good preservation; 100 ft. iron- stone and sand; sand continued more or less to 130 ft.; gravel, sand, and water, came up pipe out of ironstone at 180 ft. 10. No. 11. Yes. 12. No. 13, No. 14. Do not know. 15. Not to my knowledge. Dr. Gill, Bootham Asylum, late of the North Riding Asylum, York. 1. North Riding Asylum, Clifton, York (north side of Asylum). 2. 40 ft. 3. There is no well; bore-hole begins at surface; depth of bore-hole 252 ft. 9 in. ; diameter 12 in. at surface, narrows to 6 in. 4. 8 ft. from surface before pumping ; after pumping 24 hours, at 7000 galls. an hour, water lowered 9 ft. from water-level. 5. 70,000 galls. have been pumped a day without altering the level of 17 ft. from surface. 6. I do not know. 7. Ido not know. No surface-water can get into the bore-hole, as it is tubed with an iron pipe nearly to the bottom. 8. The water is an ordinary hard water; contains only a small percentage of sulphate of lime, but quite an appreciable quantity of iron; it is very drinkable.’ 9. Ist, 7 ft. of sand; 1 ft. of peat moss; 18 ft. dense blue clay; 23 ft. dense blue clay, containing boulders, many of which are ice-worn; 10 ft. red sand; 16 ft. soft red sandstone (with layers of slate?) ; 23 ft. white sandstone; 25 ft. red sandstone, with layers of red clay and soft slate; 10 ft. white sandstone; 6 in, red clay; 20 ft. red sand- stone ; 8 ft. white sandstone; 1 ft. red clay; 15 ft. white sandstone ; 8 ft. red sand- stone; 2 ft. white sandstone, containing large quantities of water; 11 ft, white sandstone ; 42 ft. red sandstone to well-bottom. 10. Yes. 11. Yes. 12. Not that I know of. 13. No. 14. Not salt springs, but some iron springs much stronger than this water has been found in boring in York. 15. Not that I know of; the bore-hole, I hear, was discontinued on account of the large quantity of iron the water contained. APPENDIX. Abstract of Analysis of Waters from the New Red Sandstone given in the 6th Report of the Royal Commission of Inquiry into the Pollution of Rivers. (Table, p. 108.) The numbers in the Table can be converted into grains per imperial gallon by multiplying them by 7, and then moving the decimal point one place to the left. The same operation transforms the hardness in the Tables into degrees of hardness on Clark’s scale. * This must probably mean 18 ft. above level of River Ouse. The well is about 30 ft. ove sea-level. ‘aTquyered pur «weo[p ‘eTqryeyed pur «rato ‘orqeyereg “prqiny ApysiIg ‘eiquyeyed pur rvo[p ‘oqeyeled = “‘prqany, ‘eqaeyered “prqany Ayysig ‘eiqeyeleq ‘“piqany Aro 4 ‘q1quyered pus «voto | 1876. . ‘erqereped “prq.ing Apysyg -oqquyeed pur «vp REPORT rere ‘Prgms “pysqg ce ‘atqeyeyed pus Bea “Sy IBuloy 108 08-26 88-2 jOSr'S | 842 | FLZ- | F00- 0 O | F1-62| F-0L | Sar 6-9 | F6-T [OFOF | OSF- | OEF- 0 0 On 09216) a 016 9-86 F-01 | 081 086°! 682 | OLL- O | 610. | 920. | 08-Fe| °° Oz P : 8ST | 26-8 |0800| 220-G| 980-6} G00. | Geo. | 680. | ZBcF] °" 00G 6-96 5 IL | GFT | OG-T OL82 | 968. | L418: | ZOO- | 400. | 420. | F0-9%] ~ 0GT 96 | 09G |O9L FE) 8c-E| 809-6} O | 020. | OG0. | #8-c9] °* 10G GET | 9IL | 9-1 | ¥6-2 |GFF'6L| 686-1] 246-1] 100. | S10. | 819. | Zee] - 6-7 | 8éL | 3 | 18% 06L'6 FFF. | TIF. O | &&0- | 910. | 00-28} ZIT OL | 49 | 19-6 |0099 | 189- | 6L49- | E00. O | 09. | F9-61} °* 961 | 96 | OF | 89.6 |OFS'E | OSF- | OTF. 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FF. 0 0 ZE0- 96-16 eee eee eee eee ee easter ereseeee 48a10 7 utr saadg “WYHONIDLO NT 020% | 19B- | FES: 0 | 220- | FOL. | 9B8E) “| Tt fet u0ySurmOg ur Sundg smypIaH “ayy : “AUINSUALSAOINT ‘ALOOSaTODA FT OFL‘'S | OTS: | 908: 0 | 400: | STO | 88-92] BOT | 008 |**** e1o4-e10q toss SuTdg Surmopy 090° | 998: | SEs 0 | 810. | 490: | 99-28) SOL |“ -| {we} Sarteyue Surads ‘peoy AoysoI1y *XUINTAOOD oe | Fea. | FOS. | TO. | GTO. | SCO: | FEET] L6 |. “* jAtoamosagzU0}4T AA Mojoq Surtdgs saute ¢ . “NVHONINUIGD orz | ¥80- | FG0- | GOO. | 8Z0- | 890. | OT-9T) ~~ | ** | Aiddng soy posodoad Surads soy sry “AUIHSMOIMAY MA ‘ANOLSUTHLY G68°9 | Fel | LIT. | G00 | FIO. | 960. | €9-08 seeveees (gorduues 9g Jo) odvioAy 0 GC0- 0 | G0. | LO0- | 8F0: | 68-68 sesseeceeseressscgarT Apu 4B a[oy-otog, u TOO ee eee eee EIST “90 “09 0 | 600: 0 | 800- | 900- | 920- | 80-08 Lromoag. ‘110.4 xoULy Jo 010q deog *AOSHUO MA cwrseeton *SYLOMTOTE AA ‘TIM Heytwi49.T O&e'T | S8T- | SOT. | ZOO. | 20. | 790. | 89-TE : stereeeeees SH IOMIOTE AA ‘TIO AA UUISA}LY 0g 8F0- | LE0- O- | TIO. | GEO. | 9F-GG @28'9 | 864: FIL O- | FIO. | T¥O-. | OF-OF * syLOMTOIE AA ‘TOA TI-ULOUIPIOD 110 REPORT—1876. Fourth Report of the Committee, consisting of Professor Harxnzss, Prof. Prestwicn, Prof. Hucuers, Rev. H. W. Crossxkey, Prof. W. Boyp Dawkins, Dr. Dreanz, Messrs. C. J. Woopwarp, L. C. Mraz, G. H. Morton, and J. E. Luz, appointed for the purpose of recording the position, height above the sea, lithological characters, size, and origin of the more important of the Erratic Blocks of England and Wales, reporting other maiters of interest connecied with the same, and taking measures for their preservation. Drawn up by the Rev. H. W. Crossxezy, Secretary. Tur Committee has pursued the same course as during former years. The time for generalization has not yet arrived. There are many erratic blocks scattered over the country as yet unrecorded, and their character and distri- bution will largely affect any conclusions that may ultimately be reached. The Committee has for its present duty the collection of facts; when its labours haye resulted in a complete account of the isolated boulders and groups of boulders of England, Wales, and Ireland, material now unavailable will exist for theoretical discussion, and many important incidents in the history of the glacial epoch will be more accurately determinable. The importance of the work undertaken by the Committee continues to be emphasized by the destruction which is constantly going on. War is waged upon the boulders (which in many cases are our only source of information respecting the epoch to which they belong) by agriculturists, and builders, and road-makers with unceasing energy. They are built into walls, buried in the earth, used as foundation-stones, and often blasted to pieces; their preservation is difficult to secure, on account of their interference with the culture of the land. In a few years it is not too much to say that the eyi- dence of glacial phenomena will in many districts be almost effaced. The Committee directs attention to (1) the distribution of erratic boulders from different centres of ice action; (2) the agencies by which they have been transported ; (3) the different periods in the glacial epoch to which they belong; (4) the heights above the sea at which they are found, indicating large changes in physical geology. The schedule of inquiry, indicating the various points of the information required, printed in a former Report, has been issued, and copies may always be had on application to the Secretary of the Committee. DxvoNsHire, A very remarkable group ‘of boulders has been reported upon by Mr. George Doe, of Great Torrington. It is found in the estate of Rivalton, in the parish of Langtree, Devon, about four miles from Great Torrington. The dimensions of the largest boulder of the group are 13 ft. x 6 ft. x 3 ft. It is subangular in form; but there are no groovings or striations. It rests on clay, close to a small brook, and is about 500 feet above the sea-level. The only legend connected with it is the old story of its having been thrown by the Devil. At the distance of about 25 ft. N.E. is another boulder 3 ft. x 34 ft. x 22 ft. At a distance of 35 yards are six small boulders, cropping out from the ground. ON THE BRRATIC BLOCKS OF ENGLAND AND WALES. iil At a distance of nearly half a mile are three more, similar to the last men- tioned. Near them is a deposit of flints in clay and a gravel-pit. All these blocks except the first are south of the large boulder. These boulders consist of felsite, resembling that in many of the “ Elvans.” A felsitic Elvan, at Tresayaen, Gwen-nap, Cornwall, cannot be discriminated from them. Possibly, however, a nearer locality may be found. OXFORDSHIRE. Professor Prestwich describes a boulder found last summer, near Oxford, in a bed of subangular flint-gravel (high-level river-grayel), at Wolvercote brick-pit, on the high road from Oxford to Woodstock, at an altitude of about 40 feet above the level of the river Isis. It consisted of a mass of hard saccharoid sandstone of concretionary origin, some portion of it broken away, and the broken edges quite angular; it weighed about three tons. It bore no trace of ice-scratches, There were no fossils to identify the sandstone ; but from general characteristics, Professor Prestwich thinks that it is of Tertiary origin. Several smaller boulders, of from 3 to 2 or 3 ft. cube, more or less worn, were dispersed irregularly through the gravel, which is scarcely at all stratified, and contains no fossils. Mrptanp CovnttEs. Dr. Deane and your Secretary have examined numerous boulders in the neighbourhood of Harborne, to W. and S.W. of Birmingham, between the Hagley and Bristol roads, One hundred and sixty rounded and subangular masses of stone have been examined in this district. Fifty-five of these are clearly traceable to local rocks—Carboniferous, Permian, or Triassic; the remainder are of distant origin. ery few of these travelled boulders are im situ. They have been rolled or dragged off the land into ditches and by roadsides. Some, when the size has been convenient, have been used by the “nailers” of the district for hammering (or rather anvil) purposes. Ninety are of the varieties of felstone so abundant in the Bromsgrove district. About half of these are of small size. Five are of considerable magnitude— ft. 6 in. x 5 ft. x from 2 to 3ft.; the rest are from 2 to 4 ft. in length and breadth, with variable thickness. One of these felstone boulders (near Hole Farm, Moor Street, about two miles east of Hales Owen) is worthy of special notice. Its dimensions are 3ft. 6 in. x 2 ft. 6 in. x 2 ft.; and it contains in one specimen the three characteristics named in a previous report as occurring separately in the boulders of Bromsgrove. A compact, almost hornstone-like matrix contains distinct included fragments and por- phyritic felspar crystals. This specimen, therefore, confirms the view that these felstone boulders, which are so numerous to the west and south of Bir- mingham, as far as and beyond Bromsgrove, are portions of highly indurated ash-beds. At Flavell’s Farm, California, is one boulder of grey granite 2 ft. by 1 ft. 8 in. by 1 ft. Vein-quartz and quartzite constitute nine small and three large boulders; and one of these, found near Harborne station, contains included brecciated fragments of rock. The size of these quartzite boulders, 112 REPFORT—1876. the largest of which measures 3 ft. x 2 ft. 6 in. x 2 ft., negatives the idea that they have come from the Bunter pebble-beds. The general character of the boulders of this district is similar to that of the Bromsgrove district; but in the presence of granite, quartz, and meta- morphic rock resembles the district north and west of Wolverhampton. North and west and south-west of Wolverhampton, however, granite is very much more abundant than in the district west and south-west of Bir- mingham. The large boulders north and west and south-west of Wolver- hampton are, it is probable, chiefly Criffell, or (more sparingly) Wigtonshire granite*; but there is Eskdale granite in the neighbourhood, especially about Bridgnorth. The Welsh felspathic drift covers abundantly the west and south-west of the Midland tableland, while felspathic rocks from the Lake-district accom- pany the Eskdale granite, and are often mixed with the Criffell granite. The boulders occur in two distinct positions—(1) in the older glacial beds, (2) in the upper clay. LANCASHIRE. Large striated boulders have recently been exposed in the extensive exca- vations which have been made in the boulder-clay at Bootle, a northern suburb of Liverpool. The site excavated is intended for new docks, and extends along the river Mersey, being reclaimed from shore within the tidal range. Mr. G. H. Morton describes for your Committee the position of these boulders, and gives the following section of the drift deposits which have been exposed continuously over many acres. The thickness of the various beds varies considerably according to position, and the middle sands and gravels often thin out and leave the upper boulder-clay reposing on the lower. Section. 1. Sand and silt, old Bootle shore .......... 17 feet. 2. Upper Boulder=elay «

b6.1 17.991 £LEt.0 60.,98 gfft1.0 £v.,g1£ $662.0 9f..9vE $Lo9.0 6£.,2L£z 109£.0 6+.,£12 £260,0 $3.,b9z gIzt.o 09..¢Lz T1Zg,0 99.0%: L¥g1.0 $1.,b6z gzlg.t 0$.,191 gtSf.o $S.,to1 6L£1.0 1b.,078 ZSSE.0 Lo.ogvf 088.0 ZZ..0L7 ; tbLt.o 26, SE L¥ZI1,0 00.,%9% obLz.0 £7.,g07% gILf.o EL. bli $$$z.0 gb. v6z LESg.r SGIgLL 6£97.0 $7,098 Ligt.o 26. bz ZIgt.0 L¥..9£€ £216,0 $8.089% 988.0 9£. 81% IL71.0 EL. blz 1g$7,0 61.,$2z 7079.0 S¥.,0L1 %007.0 69.5262 3598.1 $6.,g51 616£.0 $0.,16 o1f1.0 LL. guzt 10tt.o Zt. VE 7566.0 87-69% g61t.0 £9.,60z oSzI.0 29..9% Sgof.o Oz. (hfe I9IZ.0 1€,,z61 14S0,0 £z.,6g2 LosL.t g$.,0S1 £12z.0 1b,,001 Sof1.0 BI. oze b£ot.o gl.,6£€ 1£g0.1 VL.099% Szot.o 3 eh 4 9611.0 Lg.,697 097.0 26.,zLz 1Z1f.0 O%.o1II 0g61.0 91.162 Lotg.1 1b,¢S1 0195.0 9%.,06 69¢1.0 ZZ. LIE Stzt.o Sg. bbe too1.1 £9.otLz vzit.o z. 512 LL11,0 65. £97 0007.0 20.,L9z O7gI.0 ZL..gb1 z6£1.0 61.,$6z vr16L.1 Lt.bS1 obLt.o LE.%6 ‘OtLI.0 $1. bit o1ft.o £S,,25€ O1o7,.I gv.,6£2 1624.0 £2.,L1z 8971.0 $z..$Lz g¥9z.0 "(ug+-2— 09-2) & d By *‘(ug—m+0--lz) ar poedg X 2 | (a-boe—Aa) ponds a ‘N ® \ ‘(a—o0—Az) poodg “a is ‘8 \ *(ug—A) poodg ty ‘I ‘3 eae oat) poadg ly ‘oO a) i ‘Ag pue 4 spaedg lg I ‘a 2 | (ig—9+4)z paadg “a ‘WS i | Cee peodg ‘a ‘Su ae ee REPORT-—1876. 280 Tee —vrAe “suOTBATasqo svat ()T JO Wrout Oy paonpep s}[nsey -ooSta0g SOOT 10}FV ; “MOOT [NY 10 Moy akon Tm om nS on -2 a ni ep 698.0 sdep GG8-T sfep oge.g dup cre. “WA. pur Ty "NI pue TL OQ pue J “‘W pur g joesegd yo uorytsoddg jooseyd jo soueptowtoy jo oseyd jo voueproutog 9£.,9S8 oF, $2 $0..$8 $Y1.,08 ®y *(ue—Az) pasdy gLS1.0 $627.0 SSob.o gIzz.0 Say ‘L f1.,b91 Z1.0$8 PS 45 80.6811 ®3 *(4—Az) paadg 8Sz0.0 10$0,0 L101.0 $1z0:0 “ar Di if a — See oN “LOST PUP 998T “COBT PUB FOBT ‘TO8T PUP OO8T “6E8T PUB Bast £g.,08% $z.,6b7 bE. 1Lz *(m@-+0¢—A) poodg 0$.,161 09.,69 Lo, ,zbz Siigges aaa *(m@—o+A) paadg $460.0 oFIt.o LZI.0 75) tL£o.0 LY10.0 I1Z0,0 Stzo.0 ‘ay “f ‘998T ‘6981 “SEST “LOST “9981 “6S8T “SgsT §z,,0be ot.o1¥ 08.04 of.,69 TI. Ive 1Z.o87 gh.ogz 16.,04 Seo. 8 *(u+05—A)z poodg gzI0.0 $z01.0 otgo.o0 060.0 6Sz0.0 Ezt1.0 gzLo.o 6Sg1.0 tifo.0 | ay W “Wy “W W “WS “Wy “Ww “Ws “"W “W ‘998T “COST ‘POST *698T E981 “1981 ‘O98T “6S8T “8981 ‘(ponunuos) purysy o1q]9F TIDAL OBSERVATIONS. 281 Fort Clinch, Fernandina Har., Florida (Lat. 30° 42’ N., Long. 81° 27' W.). Year 1860-61. A,=6-4451ft. I=26°°6. S M K O ie J Q Speed 2(y—7) -2(y—) (2y) (y-20) (y—2n) (y+o-—@) (y—30+a) ft. ft. ft. ft. ft. ft. ft. R, 0'0724 00282 0°3606 02753 O'l170 0'0375 » 0'0627 € 91°90 25°73, 2049384242 25°10 23935 471 R, 04745 2°8338 OMATAL mare \etseg Cet bP E OMEN 4 eet € 252°°09 221°°11 SOMOTOMNM OR css ok | aekaed | Sees Oe Me ee apias ClOSATEAEE Mies Peete ie acca a eee a 72 Gndate BE) tod. Seine MMP ia stirs Mh aan Oe logs Fico, R, 070234 CIOS7OMMMEMINS cs. Saeco AL ssccee OSA a ess. (Sm EOE COSY) Ta em cere tne Cre aa RMR 8 eon dt nee iia igeente O;O302 eee memes. 6 ANS, WE nc yf ee BEB Es Tee tn, SO ae ci Si cinta mailto i Meek wat Caen Mee See yal aR 8 Dy) Bea 00103 Ritasce | BNaeaise p 1) Mapatanle Wiemeeertt-is Gs Béetoc GS GeO iets Ses See cave Me Vans Nacembemetasciseke ie of, ona N r v pe (2y-o—w). (2y—30+m). (2y—0+w—2n). (2y—30—w—2n) (2y—80—-—w+2n). 2 070969 0°6843 0°1073 O°1474. 0"0992 6, 36°24. 206° 19 316°°86 215°02 241° 25 Coincidence of phase of Sand M. P and O. 1-271 days —0°710 of a day 11 — ~ After New or Full Moon, San Diego, California (Lat. 32° 42 Coincidence of phase of M and N. Opposition of phase of L and M, —0°373 of a day — 42 days ce aca After Moon’s Perigee. 'N., Long. 117° 13' W.). S. Speed 2(y—7). M. Speed 2(y—o). MS. Speed (4y—20—2n). ae ae gs = aaa EN at phe 1860. 1861. 1860. 1861. A, 5°9089 57864. T= 26°°6 packed ft. ft. R, 00303 070249 0°1026 COOLS, © Ge Gren teak Prk cee. €, 228°'90 246°°32 25°°8r S440 96k Sais) SeesPar ese) so R, 0°6969 0°6934 1°6827 EE ie AER OE abe ey eee Be 273°°33 275°°42 272°°75 De Goi. RR ene a St = uidpedeeh. 2 dane 0°0074. OCO7 Le ety eel ee Shad 22) RRC ee 2 ane 14°°69 TSE OZ, | MRS Beg 5) tS R, 0'0066 0°0052 0°0268 0°0267 0°0061 O°O124 €, 18691 221°08 201° 62 195°°99 186° 12 188°90 [hi S iiede-a aR 0°0092 CLOTZG srg Bo aiescet sal gh ee Jo QRGRETES #9 tpeteata 82°28 FRO A Om ee Nera MIL K. Speed (2y). O. Speed (y—2c). P. Speed (y—2y). ——~—_——_-.. X —~ ek =i = 1860. 1861. 1860. 1861. 1860. 1861. R, 1'1760 1°1386 °°7749 0°7426 0°3515 03612 €& —-176°"69 176°°45 354°°74 358°'03 o°"70 359°°8r R, 0'2469 re EO @ocnda. Se es ee Cy 246°°06 IGE LM SA es ame i ee a 282 - REPORT—1876. J. Speed (y+v—a). am A ——_——_—_ 1860. 1861. R, 0°0752 0'1067 €; 176°°40 180°°80 L. Speed (2y —o—w). N. Speed (2y—30+a). Q. Speed (y—30—a). Cane ems 1860. 1861. o°1440 01698 35°09 356°°33 > rae < — aN 1860. 1861. 1860. 1861. 1860. 1861. R, oO'oIgI 00052 04060 04363 0°0678 00486 € 174°°64 163°°62 255°°99 259°14 357765 85°64 vy. Speed (2y—30—ma+2n). p. Speed (2y—20+7). co SS SS ee 1860. 1861. 1860. 1861. 0°1309 0°0687 0'0373 o°O150 258°°76 230°'96 240°°68 230°°74. R. Speed (2y—n). SSS 1860 and 1861. R, o'o104. €, 253°°14 Coincidence of phase of S and M. Pand O. 0:030 of aday 0:159 of a day After New or Full Moon. — T. Speed (2y—38n). Fe 1860 and 1861. 070408 38°12 Coincidence of Opposition of phase of Mand N. phase of L and M. 1-230 days 5711 days —. — ate After Moon’s Perigee. —— X. Speed (2y—0+m+2n), ae es ee pea EE Deduced from mean values for 2 years. A series of tide-observations extending through five years, com- mencing 1868, May 1, taken by the Manora self-registering tide-gauge at Kurrachee, were also kindly lent by Mr. Parkes for the purpose of reduction. The following series have been analyzed for each year separately, with the exception of the solar semidiurnal tide-components R and T, for which it is necessary to combine the observations extending through two entire years. The datum-line is 2 feet below the datum-line of the diagram-sheets. Kurrachee (Lat. 24° 53’ N., Long. 4" 28™ E. of Greenwich). Year ... 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. ft. ft. ft. ft. - ft. Ay eas 72908 7°2644 771068 7°0510 5 er92-6 212 2.3°0 24°°6 262%, 8. Speed of semidiurnal 2(y—7). a — AL, lL ae << > | 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. R, 00718 o°0712 070750 070829 "1082 oa 176°°57 187°"50 162°°29 158°°20 147°°41 R, 0°9323 0°9425 op235 019522 O195TS €, 322972, 323°°68 323°°68 321°°94 321°°56 R, very small. _yery small. oO'OI4I 070126 070083 G5o Behe eee 355°°95 4°°54 0°00 Ri i SES ee eee Ue dre _ 0°0036 O°O117 he: ")EReat Matai eet oe Lamar. ohn 292°°99 295°°25 ape TIDAL OBSERVATIONS. M. Speed of semidiurnal 2(y—<). 288 fa = 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. OOLS) SP cy eccs O'0510 0'0712 00565 271°'60 Senos 329°18 229°°28 131925 2°5859 2°4974 24717 2°4822 24374 295°°78 297° 24 2.96°°62 295°°66 295°°66 0°0439 0°0382 0°04.92 0°0477 0°0355 335°°18 336°°09 325°°46 335°°54 319°°15 o'0169 070284 0°0242 0°0294 o'olgt 47°°04 30°41 31°°70 27°11 32°19 0°0444. 0°04.94, 0°0445 0704.45 0°04.44. 225°°91 215°°16 224.°°55 209°°56 219°°89 SARC Ee ee wi Goce Gaile Be 8) Le Secor 0°0062 00058 ct 0tig py ee acco ee coe PEC) 273°°49 K. Speed of semidiurnal (2y). ete Se Se ee 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. 1°1669 1°1907 12392 1°3128 1°3523 142°°87 144°°73 146°°87 14504 143°°43 0°2389 0'2355 ogaGy oae7a "3339 340°°25 330°°57 330°°94 338°°16 336°°57 O. Speed (y—2c). —_— OO TO - I TOM ———_ —_—_—. 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. 05688 075905 06164 _0°6633 0°6g27 308°'87 309°°94 306°°97 307°°07 307012 P. Speed (y—2n). sa eS ee Os a, 6 Rs aa Se 1868-69. 1869-70. 1870-71. 1871-72. 1872-75. 0°3755 0°3850 0°3746 0°3598 0°3678 316°°35 320°°27 314°°97 317° 91 317°°44 J. Speed (y+o—qam). (== oo Be SSS Se 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. 0'0800 0°0434. 0°0686 O'1123 071138 178°°58 165°°88 141°°37 163°°56 182°°81 Q. Speed (y—38e+a). Ee ——-~ 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. O'I110 o"1100 0°1354 O1515 O'I4II 308923 320°°34 313°°O5 309°°98 313°°54 L. Speed (2y—0—@). a a eS a 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. 00804 0°0365 0°0824 o'0519 o'r561 108°-67 14.0°°69 129°°68 184°°24 72°°06 N. Speed (2y—30+qa). am — eee FF 1868-69. 1869-70. 1870-71. 1871-72. 1872-73, 0°6221 0°5987 0°5756 0°6473 0°5947 280°°31 282°°83 281°°35 ~ 281°°96 276979 284 REPORT—1876. rX. Speed (2y—c+w—2n). i a a SS 868-69, 1869-70. 1870-71. 1871-72. 1872-73. R, 0'0613 0°0381 0°0432 0'0839 0'0750 6, 156°°46 91°56 30°°71 29°40 194°°00 vy. Speed (2y—30—mw+2n). 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. R, O'1955 070832 0°08 14. O'1415 o1881 Ey 255°°63 224°°40 34.5°°20 285°°98 302°03 pe. Speed (2y—40+42). ETE oa ae a ae a a 1868-69. 1869-70. 1870-71. 1871-72. 1872-73. R, 00703 0'0333 0°0714 0°0617 0°05 34. €, 269°"99 2279-72) 304°°53 2.58°°49 273°°84 MS. Speed (4y—20—2y). oo 1868-69. 1869-70. 1870-71. 1871-72. R, 00173 070236 0'0311 00195 € 216°°79 181°30 326°°55 0°05 R. Speed (2y—y). ee —SS 1868-69 and 1869-70. 1870-71 and 1871-72. R, 0°0353 0°0272 6, 12°04. A2ro28. T. Speed (2y—3n). a aoe eee ee ———“ —<—S>— 1868-69 and 1869-70. 1870-71 and 1871-72. R, o'r108 0'0576 €, 38°96 101°70 Long-period Tides. 1868-69. 1869-70. 1870-71. ft. ft. ft. . : "16 $ Bore ns x nee ; enone : Bee a | Solar annual (elliptic) tide. Speed (m), R 0'198 0'059 0°062 | Solar semiannual (declinational) tide. Be uy 116°°93 69°69 Speed (27). R 0076 0°043 coat Lunar monthly (elliptic) tide. € 247°°73 175727 115°90 Speed (o—w). R 0'038 0°064 0°035 | Lunar fortnightly (declinational) tide. € 335°°40 338001 283°°22 Speed (20). R 0009 0°075 0058 | Lunisolar synodic fortnightly (shallow-water) 6 32619 16°98 156°°62 tide. Speed 2(o—n). Three years’ tidal observations, taken at Fort Point (lat. 37° 40’ N., long. 8" 9™ W. of Greenwich), San Francisco Bay, California, were received and analyzed, with the following results :— Year ... 1858-59, 1859-60. 1860-61. ft. ft. ft. A, =8'7103 $2651 81608 T= 28%0 26°'9 25°°4 TIDAL OBSERVATIONS. 285 S. Speed of semidiurnal 2(7—7). M. Speed of semidiurnal 2(y—c) A. ———_—_— $$$ __—. as SS aa 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. R, 00146 ~=very small. very small. 0'0539 0°0808 0'0863 e BETOO 6 cscasve J). serve c 46°°30 189°°37 32°°71 R, 0°4067 0°3802 0°3824. 1°6694. 1°6215 1°6645 6 334°"24 —335°B0 3 36°45 330°°RE = 33130 328972 Eee ices | tances very small, very small. very small, Caters OO See cee, SU IE MD et oD TR AO: De R, verysmall. very small, yery small °° 06 16 o°0712 070698 DEMME oS) ) oT Laseee ditt [)scvene 23092, 26°°73 TITS MS. Speed (4y—2c0—2n). 1858-59. 1859-60. 1860-61. R, 0'0248 00325 0°0315 € cule) 12°25 22°°81 pe. Speed 2(y—2e+7). a ew 1858-59. 1859-60. 1860-61. R, 00257 O'O3II 00252 & -254°°34 206° 14 209°°53 K. Speed of semidiurnal (2y). a= —— a 1858-59. 1859-60. 1860-61. R, 1°3370 1°3036 1°2925 €) 192°°17 190°°88 188° 55 R, O°1759 0'1716 O'1351 €, — 326°°65 314°°53 308°°75 O. Speed (y—2ce). P. Speed od (7 _ eee 1858-59. 1859-60. 1860-61. “1858- 59. 1850. 60. 1860- 61. R, 0°8917 o'8511 0°8784 0°3672 0°3659 0°3869 By y.3°:39 6°25 4eror BGS Ge nS Od) maa L. Sheed igs o—@). N. Speed (2y—3c+a). ——— A FT — ee eee 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61, R, 00591 0°0370 070506 0°3931 0°3494 0°3545 6 102°°63 183°'00 170°°16 303°°46 305°°53 302°°51 R. Speed (2y— ” T. Speed d (2y— pete 1858-59 Ga 1859- 60. 1858-59 = 1859-60. R, 00076 R, O'0142 €, 164°00 €, 277°°90 dh. Speed (2y—c0+m—2n). v. Speed (2y—30—w+2n). ae (a TF 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. R, 0'0372 0°0275 O'OI21 orlo44 0'03387 0°0437 6, 188° 30 156°39 144°'18 28723 272°°46 349°°59 J. Speed (yt+o—qa). Q. Speed (y—30+7). ee Ss 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. R, o'0819 0°0376 0°0565 0°1706 o°1056 0°1332 € 213°%98 = 208°"2g 83°40 353; OSe0 Baro aa 8°93 Coincidence of phase of Coincidence of Opposition of S and M. P and O. phase of Mand N. phase of L and M. 0:214 ofaday 0-441 of a day 2-024 ESE 0-126 of a day — ~\~-—— ——— cers => ees After New cad Full Moon. “After Moon's 8 perigees, 286 REPORT—1876. Remark an abrupt diminution in the height of mean level after the first two years, which the following extract from a letter received from Prof. J. E. Hilgard fully explains :— “ The change in the mean-level reading at Fort Point is a matter of much “ annoyance to us. The tide-gauge was put up in a small building near the “end of a wharf, and the tide-staff used for comparison was close to it. ‘“< Now it was observed after the observations had continued some time that ‘‘the wharf was settling, at least the part where the gauge stood. Then “the gauge was moved to a point a little nearer to the shore believed to be ‘“¢ firm ; but we think the whole wharf settled and continued to do so for years. “There seems to be a bog-formation underlying the surface deposit at that ‘‘ place. There is probably no way of ascertaining the amount of settling “ except from the observations themselves. We are now having frequent « levellings made, referring the tide-staff to a rocky ledge further inland.” Cat Island, Gulf of Mexico (Lat. 30° 23' N., Long. 5" 56" W. of Greenwich). The following results represent the tide-components as far as they have at present been evaluated. Datum 10 feet below datum of United-States Coast Survey :— Year 1848. A,=4°8574 ft. I=18°45. Ss M L N Speed Ayn) Ay—9) Ay—do— Iw) Ay—4o+ ba) ' 070442 Solem FE ge e ee | 10°04. Gaerne ste > g® Sone R, 0°0677 O1IQS oo118 0'0269 €5 23°°80 10°75 222°°40 Zee oO iP Speed ...... 2(y) (y—20) (y-2n) (y+to-—w) (y-30+7) 1 0°4627 0°3855 O°1559 0°0292 * 0°0733 e; 55°20 224°°29 230°°65 28°22 215°°32 R, OUZOR yy shaven |e eee ee ll seasear sal On cera et QSBeNma NM tre |e iiesen DOU) lh essere ges wulaweee It is extremely interesting to find that, although the lunar and solar semidiurnal tides are very small in value, the series of means from which they were obtained being extremely regular and good, the consequent de- termination of the phase of spring-tides from their respective epochs is probably correct within a few minutes. The proportion between the ampli- tudes of the lunar and solar semidiurnal tides is the nearest approach to equality yet obtained, being in the ratio of 11 to 6. The comparatively large value of R, of Series S is undoubtedly a genuine tide; but the smallness of the corresponding value of Series M must forbid the conclusion of its being purely astronomical. It is perhaps produced by temperature or wind, its time of maximum being about 40 minutes after noon. There are also indications ot a similar and large annual tide of 0-274 foot amplitude, and maximum about Aug. 16, which is also probably meteorological in its origin. The proportion between the lunar and solar diurnal (Declinational) tides (R, of Series O and P) will be, on the assumption of the variation of R, of Series O being as the square of the sine of the declination, about 4 to 1. The following are the values of the long-period tides :— TIDAL OBSERVATIONS, 287 R. €. ft. F Solar annual tide (elliptic and meteorological) ........ 0'274. 14450 Solar semiannual tide (declinational and meteor ‘ological) ... o°128 35°02 Lunar monthly tide (elliptic) ...........cseeeseseeeeeeesees Sher 07106 304/17 Lunar fortnightly tide (declinational) ...............cseseceeeeee 0°043 136°69 Lunisolar fortnightly tide (synodic) ..............:seceeeeeeeeeeee 0°099 33626 The results of three years’ tide-observations taken at West Hartlepool, England (Lat. 54° 41’ N., Long. 1° 12’ W.), by a self-registering tide-gauge, from 1858, July 1, to 1861, July 5 :— Year ... Inclination of Lunar orbit to Earth’ °| I equator PeeeeeOeeeeeee ere ere eee eee Mean sea-level above datum 12 st Ay = 12°1518 below mean level of diagrams...... S. Speed of semidiurnal 2(y—7). Nee —~ —~ 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. R o°'0192 00542 070248 0'0376 0°0635 00397 1 131°°33 156° 75 168°°'83 hay 47°57 46°°87 R, 1°7543 I°7107 1°7492 50062 50181 5°O9Or G& 40%5O 138°%09 = 137987 97°°59 97°17 94°'58 Ula. 2 apse zcsies Saar octet iimweconen 0°0358 0°0217 0°0453 €, Sac, MVR OER uke diiedadc 120°°01 103°°12 124°15 R, 00253 070212 o"0190 0°0746 "1006 00958 & 190° 24. 173078 TO 53 100°'63 113°°91 102°°64. Ly UR Gaodse ener Arm arccey ee 00643 00716 0°0704, Sn SBoaday! IF octe eae 47°10 50°11 40°08 K. Speed of semidiurnal (2y). a —— $$ ——_—_——. 1858-59, 1859-60. 1860-61. R, 0°42.98 0°3961 0°4065 Gj . 343° "63 331°°54 330°°61 R, 0°6218 0°6225 075298 €5 131°°36 123°21 116° 02 O. Speed (y—2c). P. Speed (y—2n). eae as Sig 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. Ry 0°5054. 04829 0°48 54 O'I211 0*°1202 0°0946 €1 357°°96 29°36 4°29 142°42 142°°44 142° 24 J. Ppeed (1 (yto—7@). Q. Speed GF anys Ja 1858- 59. 1850-60. 1860-61. 1858-59. 1850-60. 1860-61, R, 00364 0'0291 o*0291 01632 0°1630 O'I751 € -353°°360 arSSr 183965 315954 = 30745 303°°77 L. Speed (2y—c—@). N. Speed (2y—5c0+7). See 1858-59. 1859-60. 1860-61. 1858-59, 1859-60. 1860-61. R, 0°2040 0°1308 O'1721 o'9195 09480 L'0251 65 274°'47 298°°70 286° 19 76°19 68°:90 70°10 rX. Speed (2y—c+w—2n). vy. Speed (2y—30—w+2n). Sagar Raa =. 1858-59. 1859-60. 1860-61. 1858-59. 1859-60, 1860-61. R, 0°05 54. 0°1068 O1153 o'r110 0°3170 o 3639 Ga. 7.926280 262°°93 293°°03 74°42 114912 71°27 1858-59. 1859-60. 1860-61. 2820 2791 25°9 ft. ft. ft. 11°9706 12'0056 M. Speed of semidiurnal 2(y—c). 288 REPORT—1876. p. Speed 2(y—20+7). aaa a SERS 1858-59. 1859-60. 1860-61. R, 0°0907 o'0951 0'0549 65 6°°57 342°°40 20°°10 MS. Speed (4y—20—27). 28M. Speed (2y+2o0—4n). CE ae TT OS ITE EN SS eee 1858-59. 1859-60. 1860-61. 1858-59. 1859-60. 1860-61. R, 0°04.54. 0'0388 00447 R, 0°0326 070332 0'0087 & 121°°48 140°°42 112°°73 5 315°°68 30°" 19 227°°66 R. Speed (2y—7). T. Speed (2y—3n). —— ————. eS Se ss 1859-60 and 1860-61. 1859-60 and 1860-61. R, 070082 0°1403 & 258°°78 279°°83 Long-period Tides, Speed ......... o. 2c. 2(6—»). 2. 2n. ft. ft. ft. ft. ft. i R 0'075 0°052 O'131 O'217 0°004 ate { € 23°°53 190°°34 70°°88 257°°63 275°°40 nO. R 0°135 0°053 o'131 0°366 0°138 eee { é 175°75 22.2°°34 57°°35 200°'02 105°°65 a R 0°139 0°073 O'r4I 0'213 o'149 Saal { € 79°'19 158°°62 54°55 199°°69 286°°62 (From mean of 3 years.) days. Coincidence of phase of S and M...........-..00.000 = 57301 : : Coincidence of phase of P and O....00...:..seeeeeees == aT Og } After New or Full Moon. Coincidence of phase of M and N,..........:sceeeeeee = 1°8898 Opposition of phase of Ti and M.....sseseeces eee eee = Sere After moon's perigee. The results of the three years’ reductions agree, on the whole, well together. The following small components, however, are somewhat discordant, viz. the elliptic diurnal tide J, the smaller component of the evection semi- diurnal tide A, and the lunisolar compound semidiurnal tide 28M. The good agreement between the separate determinations of the mean sea- level renders Hartlepool a favourable place for the purposes of trigonometrical survey, the annual tide also being much less in amount than at Liverpool, to the mean sea-level of which the present survey of the United Kingdom is referred. The values of the diurnal components are as large as those for Liverpool, where the mean solar and lunar semidiurnal tides aré nearly double the values of those for Hartlepool, and are the largest yct evaluated for English ports. The value of the smaller elliptic semidiurnal tide (L) agrees very nearly with the equilibrium-theory value of the values of this component for other English ports, being considerably in excess of the theoretically assigned value. The larger component (N) agrees exactly with that deduced from theory. A remarkable point in the deductions is the smallness of the overtides of the chief semidiurnal tides, and also of the compound lunisolar quarter- diurnal tide (MS), which have been well marked in the other English ports of which the observations have been analyzed. There is scarcely sufficient agreement between the results deduced from TIDAL OBSERVATIONS. 289 the long-period tides to be satisfactory, although the quantities of some are within reasonable limits. The values for y, as usual, show an undoubtedly genuine annual tide of about three inches with its maximum about the end of October or beginning of November, which agrees with the time given for other English ports. Of the other long-period tides, the synodic fortnightly [2(¢—n)] gives a fair agreement between the values deduced from the separate years. : Results of Hourly Tide-observations taken at Port Leopold, Arctic Archi- pelago, by Sir James Clark Ross, from 1848, Noy. 1, to 1849, July 31. (Lat. 74° N., Long. 91° W.) I, or inclination of moon’s orbit to earth’s equator, = 1897. s M L N K Speed... 2(y—7n) 2(y—0) (2y-—o0—w) (2y—30+a) (2y) ft. ft. ft. ft. ft. Ri 070308 CGFA! M MAAelg so Hao - 0°7997 €, 26°°55 269%19N samacrs Gia ond aerines 309°°62 R, 064.32 20736 00513 0°4345 0°1325 6, 28°°78 338°°88 189°°18 306°°36 34°°99 R, 0'0065 OOLGOT wey afachner romain neate dygenda leageks €4 256°°84 PSS IEN SY: ama ay BPP RY Rg! cRNA a ROPE Pia) FP Pe O P Speed ... (y—2c) (y—2n) F 0°3632 o'2161 €| 69°64 T27 cues days. Coincidence of phase of S and M...... = 2°0467 Coincidence of phase of P and O...... See viggs } After New or Full Moon. Coincidence of phase of M and N...... = 274891 ; : Opposition of phase of L and M ...... pat After moon's perigees. Results of Hourly Tide-observations taken at Beechey Island, Erebus Bay, Arctic Archipelago, by Captain Pullen, for 119 days, commencing 1858, Noy. 2. (Lat. 74° 43' N., Long. 91° 54’ W.) I, or inclination of moon’s orbit to earth’s equator, = 28° o. s M L N Speed... 2(y—n) 2(y—-0) (2y-—0-—w) (2y—30+a) ft. ft. ft. ft. R, 0636 1°930 0°0867 0°4.149 & 33°71 345°°92 209°'or 313°°51 R, very small TZ CANT BL TNT SN AYR Egf? lo pod Lee 265988) eiyouehl watdas Pose K O P Speed ... 2(y) (y—2e) (y—2n) R, 0"9930 0°570 O'2150 €) 329°°15 75°°84. Da2een ne is CRIGAA I Ms .cscs gaate €y ADOC GP re a amescate oa days. Coincidence of phase of S and M...... = 1'9601 Coincidence of phase of P and O...... = at After New or Full Moon. Coincidence of phase of Mand N....... = 2°4807 After : : Opposition of phase of Land M...... = 3'2981 Se es Poona Lod 1876. U 290 REPORT—1876. The tides at Port Leopold and at Beechey Island, as seen from the above analyzed constituents (due allowance being given to the different values for I), are almost identical in character, the agreements of the components when compared being remarkably close. The diurnal components are large, and in the years of maximum declination of moon nearly sufficient at certain parts of the lunation to reduce the period of the tide to that of one tide only in the twenty-four hours. The narrrowness of Behring’s Straits precludes the supposition that the tides in the Arctic Ocean and among the channels of the Arctic Archipelago are sensibly influenced by communication through it with the Pacific. The largeness of the values for the retardation of spring-tides renders it probable that for these places the tidal influence is derived chiefly from the Atlantic Ocean, and not by direct action of Sun and Moon on the waters of the Arctic Ocean. The shortness of the series of these observations, especially those for Beechey Island, has rendered some departure from the usual mode of reduction desirable. The following explanation is therefore necessary :—The observa- tions were first grouped according to mean solar hours, and the summations and means obtained and the means analyzed. The values of the mean solar amplitudes thus obtained were then used for the calculation of the height of the tide at each integral mean solar hour due to these constituents. The heights were then copied for the previous values grouped according to mean solar hours, subtracting from each quantity the effect of the height due to the mean sun, computed as above explained. These numbers were grouped according to mean lunar hours, and the series of mean values analyzed as before. The value of the tide at each mean lunar hour was then computed and subtracted from the previously copied series, and grouped according to sidereal hours and the reduction continued as before ; and so on throughout the seven evaluated series, The values obtained for the smaller components found by these means are no doubt trustworthy. Notes on the Reductions of the Tidal Observations of Brest and Toulon. By Mr. Rozerrs. ‘‘ With the kind assistance of M. Janssen the tracings from the original “ registered tidal observations at Toulon for the whole of the year 1853 were ‘“‘ obtained from the Department of the Marine at Paris, and also a copy of “the heights at Brest for the year 1875. These two years’ observations have “‘ been treated and reduced in a similar manner to the many years’ tidal obser- ‘‘ vations fully described in the Reports of the Tidal Committee of the British *“‘ Association for the years 1868 to 1872. It will therefore be only necessary “in this place to give a general summary of the results obtained. The ob- ‘“‘ servations being given in metres, the results have been similarly expressed ‘in decimetres and centimetres, and not in English feet. * Brest. ‘“‘ The proportion between the solar and lunar semidiurnal tides at Brest is “ (allowing for the value of the Moon’s declination) about as 1 to 3, and TIDAL OBSERVATIONS. 291 “agrees fairly with the proportion found at most British ports. The elliptic *‘semidiurnal tides agree within narrow limits with the values assigned by “theory, as also those of the Hvection and Variation semidiurnal. The “‘oyertides here, as at Toulon, are small, the mean lunar quarter-diurnal “components amounting to 4°38 centimetres only, the main lunar semi- “diurnal tide being 1:9887 metre. The terdiurnal component is about ,1, “ of the chief tide, which accords with the proportion found at British ports. “The diurnal components at Brest are very small, and are only about double “the amounts found for Toulon, although the range of tide is about thirty “* times greater. * Toulon. «The proportion between the solar and lunar semidiurnal tides at Toulon, “having regard to the faet that the inclination of the Moon’s maximum “orbit to the earth’s equator for the year reduced was nearly at its greatest, “agrees very nearly with that assigned to it by the Equilibrium theory, and ** was found to be about as 1 to 2:2. The overtides of the main semidiurnal “components were found to be very small, the largest, that of the first over- “tide of the lunar semidiurnal, scarcely exceeding 3 millimetres. The ter- “diurnal lunar tide amounts to about ;4, of the main lunar semidiurnal, the “* proportion generally found for this component from many years’ reductions “at different ports being about z!) of the chief component. The proportion “between the longer elliptic and the lunar semidiurnal is somewhat larger “than the deduced value according to the equilibrium theory, although that “between the larger and smaller components agrees almost exactly. The “‘semidiurnal tides depending on the lunar perturbations of Evection and “ Variation agree within reasonable limits with the equilibrium theoretical “proportions. ‘The evaluated diurnal components are very large, the luni- “ solar exceeding in value the mean solar semidiurnal. These large diurnal “components give to the Mediterranean tides a totally different character “from those of the North Atlantic, in which the diurnal tides are very small. “The coincidence of phase of the main lunar and solar semidiurnal ‘tides “happening some 4 or 5 hours before the time of New or Full Moon would “ point to the conclusion that the tides at Toulon were wholly generated in the “ Mediterranean, and were scarcely if at all influenced by any action of the * North Atlantic through the Straits of Gibraltar, the amount of reterdation * of coincidence of phase for these components amounting on the western coast *‘ of Europe to between 30 and 40 hours. The evaluation of the long-period * tides places the maximum of the solar annual tide at Dec. 80. The value “of the junar declinational fortnightly tide is about 14 centimetres, or . 6. inch.” 10 v2 1876. 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SMOT[OF sv oq WOYY JoT *s1v4s [eapT 10 ,‘s}IOy solyse ,, 800B[deT Osn 0} FUSTUOAUOD SI 4I S}[NseI Jo se[quy, Surpooord oyy ut UoALs 2 Jo sonTea oy} Jo Suruvow oy} ureydxo oJ, 9 fo uoynusfog 294 REPORT—1876. To facilitate comparisons between the various results of the harmonic ana- lysis contained in this and the preceding Reports, and to promote a complete theoretical appreciation of them all, the following harmonic analysis of the equilibrium tide will be found useful. A portion of it, that, namely, per- taining to the mean semidiurnal, the declinational semidiurnal and the elliptic semidiurnal constituents, was given in the Report for 1872 ($$ 48, 50). For the sake of clearness, an investigation of the equilibrium tide, consisting chiefly of extracts from Thomson and Tait’s ‘ Natural Philosophy,’ vol. i., is premised, as the first edition of that work is out of print, and the second edition can scarcely appear until after the publication of this Report. Let E denote the earth’s mass, M the mass of the moon or sun, D the dis- tance between the centres of the two bodies, a the earth’s radius. If we neglect tides depending on the fourth and higher powers of ‘ (of which only one, Laplace’s terdiurnal lunar tide, referred to in § 3 of the Committee’s Report for 1868, and again in § 5, 1872, can probably be sensible), the equi- librium tide will not be altered by the following arbitrary but conveniently symmetrical assumption. Imagine M to be divided into two halves, and let these be fixed at distances each equal to D on opposite sides of the earth in a line through its centre. Then if 7, @ be polar coordinates of any point referred to the earth’s centre as origin, and the line joining the two disturbing bodies as axis, the equation of an equipotential surface is [Thomson and Tait, §$ 804-811] E al 7 1 0 Te! ETD BrDeosb+r) =const. . (11), 7 + 2M Lp a Deosd +) FF 7 (D¥ + 2rDeosd-+75)" const (11) , and as the first approximation for D is very small, we have oe DLLTEE (800s"9—1)]=const. : eae whence finally, if r=a+w«, w being infinitely small, s=-i S@oo¥—le #. aa. ED* This is a spherical surface harmonic of the second order, and as is ove quarter of the ratio that the difference between the moon’s attraction on the nearest and furthest parts of the earth bears to terrestrial gravity. Hence “The fluid. will be disturbed into a prolate ellipsoidal figure, with its long axis in the line joining the two disturbing bodies, and with ellipticity: equal to ? of the ratio which the difference of attractions of one of the dis- turbing bodies on the nearest and furthest points of the fluid surface bears to the surface value of the attraction of the nucleus. If, for instance, we sup- pose the moon to be divided into two halves, and these to be fixed on opposite sides of the earth at distances each equal to the true moon’s mean distance, hes : : 3 the ellipticit: eee e bis icity of the disturbed terrestrial level would be 3x60 x 300000" 73,000,000" and the whole difference of levels from highest to lowest would be about 14 feet. We shall have much occasion to use this hypothesis in vol, ii. in investigating the kinetic theory of the tides. TIDAL OBSERVATIONS. 295 “805. The rise and fall of water at any point of the earth’s surface we may now imagine to be produced by making these two disturbing bodies (moon and anti-moon, as we may call them for brevity) revolve round the earth’s axis once in the lunar twenty-four hours, with the line joiniig them always in- clined to the earth’s equator at an angle equal to the moon’s declination. If we assume that at each moment the condition of hydrostatic equilibrium is fulfilled, that is, that the free liquid surface is perpendicular to the resultant force, we have what is called the ‘ equilibrium theory of the tides.’ «806. But even on this equilibrium theory, the rise and fall at any place would be most falsely estimated if we were to take it, as we believe it is generally taken, as the rise and fall of the spheroidal surface that would bound the water were there no dry land (uncovered solid). To illustrate this state- ment, let us imagine the ocean to consist of two circular lakes A and B, with their centres 90° asunder, on the equator, communicating with one another by a narrow channel. In the course of the lunar twelve hours the level of lake A would rise and fall, and that of lake B would simultaneously fall and rise to maximum deviations from the mean level. Ifthe areas of the two lakes were equal, their tides would be equal, and would amount in each to about ¢ of a foot above and below the mean level; but not so if the areas were unequal. Thus, if the diameter of the greater be but a small part of the earth’s qua- drant, not more, let us say, than 20°, the amounts of the rise and fall in the two lakes will be inversely as their areas to a close degree of approximation. For instance, if the diameter of B be only ;}, of the diameter of A, the rise and fall in A will be scarcely sensible ; while the level of B will rise and fall by about 12 feet above and below its mean; just as the rise and fall of level in the open cistern of an ordinary barometer is but small in comparison with fall and rise in the tube. Or, if there be two large lakes, A, A’, at opposite extremities of an equatorial diameter, two small ones, B, B’, at two ends of the equatorial diameter perpendicular to that one, and two small lakes, C, C’, at two ends of the polar axis, the largest of these being, however, still supposed to extend over only a small portion of the earth’s curvature, and all the six lakes communicate with one another freely by canals or underground tunnels : there will be no sensible tides in the lakes A and A’; in B and B’ there will be high water of 12 feet above mean level when the moon or anti-moon is in the zenith, and low water of 12 feet below mean when the moon is rising or setting; and at C and C’ there will be tides rising and falling ¢ of a foot above and below the mean, the time of low water being when the moon or anti-moon is in the meridian of A, and of high water when they are on the horizon of A. The simplest way of viewing the case for the extreme circum- stances we have now supposed is, first, to consider the spheroidal surface that would bound the water at any moment if there were no dry land, and then to imagine this whole surface lowered or elevated all round by the amount required to keep the height at A and A’ invariable. Or, if there be a large lake A in any part of the earth, communicating by canals with small lakes over various parts of the surface, having in all but a small area of water in comparison with that of A, the tides in any of these will be found by drawing a spheroidal surface of 12 feet difference between greatest and least radius, and, without disturbing its centre, adding or subtracting from each radius such a length, the same for all, as shall do away with rise or fall at A. ** 807. It is, however, only on the extreme supposition we have made, cf one water area much larger than all the others taken together, but yet itself covering only a small part of the earth’s curvature, that the rise and fall can be done away with nearly altogether in one place, and doubled in another 296 REPORT—1876. place. Taking the actual figure of the earth’s sea-surface, we must subtract a certain positive or negative quantity a from the radius of the spheroid that would bound the water were there no land, a being determined, according to the moon’s position, to fulfil the condition that the volume of the water remains unchanged, and being the same for all points of the sea at the same time. Many writers on the tides have overlooked this obvious and essential principle ; indeed we know of only one sentence* hitherto published in which any consciousness of it has been indicated. “The quantity « is a spherical harmonic function of the second order of the moon’s declination and hour-angle from the meridian of Greenwich, of which the five constant coefficients depend merely on the configuration of land and water, and may be easily estimated approximately by not very laborious qua- dratures, with data derived from the inspection of good maps. *€ 808. Let as above ree) eunsultculs Joma be the spheroidal level that would bound the water were the whole solid covered ; u being given by (13) of § 804. Thus, if f/do denote surface in- tegration over the whole surface of the sea, affude expresses the addition (positive or negative as the case may be) to the volume required to let the water stand to this level everywhere. To do away with this change of volume we must suppose the whole surface lowered equally all over by such an amount «(positive or negative) as shall equalize it. Hence if © be the whole area of sea, we have poate ik fudo Q And rar—anafl+u— Lee, joinlls SarRsaeHe od VERE is the corrected equation of the level spheroidal surface of the sea. Hence haa{u— eles shit ole inaoa.autt «et aan OC where h denotes the height of the surface of the sea at any place above the level which it would take if the moon were removed. “To work out (15), put first, for brevity, Ma’ : r=3 a . (18): and (13) becomes U=2 (CON Gr= 2) «>= vaententey eae mg Fs Now let J and \ be the geographical latitude and west longitude of the place to which wu corresponds ; and y and é the moon’s hour-angle from the meri- dian of Greenwich, and her declination. As @ is the moon’s zenith distance at the place (corrected for parallax), we have by spherical trigonometry cos 6=cos/ cos 6 cos(A—w)+sin /sin 8; which gives 3.cos*9—1= $cos"l cos*dcos2( — ) + 6sin Zcos7sin 8 cosé cos(A — W) + 2(3sin*6—1)(3sin7— 1)(20). “Rigidity of the Earth,” §17, Phil. Trans. 1862. TIDAL OBSERVATIONS. 297 Hence if we take A, %, €, DB, E to denote five integrals depending solely on the distribution of land and water, expressed as follows :— = Jf cos*l cos 2ddo, p= : Sf cos*l sin 2)do, C= + ffsin Leoslcos\do, D= 2 ff sindcos?sinddo, >. . (21). = {f Bsinl—1)do, where of course do=cos ldldy, we have a =5 /fude= 3ar{3cos*s(Acos2) + 8 sin2y) + 6 sing cosd(Ccosp + Bsin) + FE(3sin*s — 1)}(22). This, used with (19) and (20) in (17), gives for the full conclusion of the equilibrium theory, A= 2ar(3 sin?2—1— €) (8 sin? 6—1) 3) + 2ar[(sin 1 cos 7 cos \A— €) cos + (sin/ cos Zsin \ —39) sin W] sind cos 6 . (23) * ? | J in which the value of + may be taken from (18) for either the moon or the sun; and 6 and y denote the declination and Greenwich hour-angle of one body or the other, as the case may be. In this expression we may of course reduce the semidiurnal terms to the form A cos(2—e), and the diurnal terms to A’ cos(W—e’). Interpreting it we have the following conclusions :— ** 809. In the equilibrium theory, the whole deviation of level at any point of the sea, due to sun and moon acting jointly, is expressed by the sum of six terms, three for each body. (1) The lunar or solar semidiurnal tide rises and falls n proportion to a simple harmonic function of the hour-angle from the meridian of Greenwich, having for period 180° of this angle (or in time, half the period of revolution relatively to the earth), with amplitude varying in simple proportion to the square of the cosine of the declination of the sun or moon, as the case may be, and therefore varying but slowly, and through but a small entire range. *«(2) The lunar or solar diurnal tide varies as a simple harmonic function of the hour-angle of period 360°, or twenty-four hours, with an amplitude varying always in simple proportion to the sine of twice the declination of the disturbing body, and therefore changing from positive maximum to negative, and back to positive maximum again, in the tropical* period of either body in its orbit. + 5 [(cos*7 cos 2\ — @) cos 2) + (cos* 7 sin 2\ — 38) sin 2)] cos* d * The tropical period differs from the sidereal period in being reckoned from the first point of Aries instead of from a line fixed in space, the difference for the case of the sun being only one in 26,000 years, and for the case of the moon one in 13 x 18°6. 298 REPORT—1876. “«(3) The lunar fortnightly or solar semiannual tide is a variation on the average height of water for the twenty-four lunar or the twenty-four solar hours, according to which there is on the whole higher water all round the equator and lower water at the poles, when the declination of the disturbing body is zero, than when it has any other value, whether north or south ; and maximum height of water at the poles and lowest at the equator, when the declination has a maximum, whether north or south. Gauss’s way of stating the circumstances on which ‘secular’ variations in the elements of the solar system depend is convenient for explaining this component of the tides. Let the two parallel circles of the north and south declination of the moon and anti-moon at any time be drawn on a geocentric spherical surface of radius equal to the moon’s distance, and let the moon’s mass be divided into two halves and distributed over them. As these circles of matter gradually vary each fortnight from the equator to maximum declination and back, the tide produced will be solely and exactly the ‘ fortnightly tide.’ “810. In the equilibrium theory as ordinarily stated, there is at any place high water of the semidiurnal tide precisely when the disturbing body, or its opposite, crosses the meridian of the place; and its amount is the same for all places in the same latitude; being as the square of the cosine of the latitude, and therefore, for instance, zero at each pole. In the corrected equilibrium theory, high water of the semidiurnal tides may be either before or after the disturbing body crosses the meridian, and its amount is very different at different places in the same latitude, and is certainly not zero at the poles. In the ordinarily stated equilibrium theory, there is, precisely at the time of transit, high water or low water of diurnal tides in the northern hemisphere according as the declination of the body is north or south; and the amount of the rise and fall is in simple proportion to the sine of twice the latitude, and therefore vanishes both at the equator and at the poles. In the corrected equilibrium theory, the time of high water may be considerably either before or after the time of transit; and its amount is very different for different places in the same latitude, and certainly not zero at either equator or poles. In the ordinary statement there is no lunar fort- nightly or semiannual tide in the latitude 35° 16’ (being sin), and its amount in other latitudes is in proportion to the deviations of the squares of their sines from the value 3. In the corrected equilibrium theory each of these tides is still the same in the same latitude, and vanishes in a certain latitude, and in any other latitudesis insimple proportion to the deviation of the squares of their sines from the square of the sine of that latitude. But the latitude where there is no tide of this class is not sin-! yi, but sin-!( 2 te), where € is V3 the mean value of 3sin*J/—1 for the whole covered portion of the earth’s surface, a quantity easily estimated by a not very laborious quadrature, from sufficiently complete geographical data of the coast lines for the whole earth. “As the fortnightly and semiannual tides most probably follow in reality very nearly the equilibrium law, it becomes a matter of great importance to evaluate this quantity; but we regret that hitherto we have not been able to undertake the work. Conversely, it is possible that careful determination of the fortnightly tides at various places, by proper reduction of tidal observa- tions, may contribute to geographical knowledge as to the amount of water surface in the hitherto unexplored districts of the arctic and antarctic regions. TIDAL OBSERVATIONS. 299 “811. The superposition of the solar semidiurnal on the lunar semidiurnal tide has been investigated above (§ 60) as an example of the composition of simple harmonic motions ; and the well-known phenomena of the ‘spring- tides’ and ‘neap-tides’ and of the ‘priming’ and ‘lagging’ have been explained. We have now only to add that observation proves for almost all places, whether oceanic islands or other open coast-stations, or in deep bays, estuaries, or tidal rivers, the proportionate difference between the heights of spring-tides and neap-tides, and the amount of the priming and lagging to be much less than estimated in § 60 on the equilibrium hypothesis; and to be very different in different places, as we shall see in vol. ii. is to be expected from the kinetic theory.” The four lunar and solar diurnal and semidiurnal tides spoken of in § 809 of the preceding extract are, in the harmonic analysis of this Com- mittee, resolved into harmonic constituents with constant amplitudes and epochs instead of the varying amplitudes and epochs which that statement implies in virtue of the varying distances of the sun and moon from the earth, and of the differences of their right ascensions from those of ideal bodies moving uniformly in the plane of the earth’s equator with constant angular velocities equal to the mean angular velocities of the sun and moon round the earth. To investigate, for either moon or sun alone, the equilibrium values of these simple harmonic constituents, and to exhibit the simple harmonic ex- pression for the long-period declinational tide represented by the first line of (238) § 80, call L the value of this line, D the value of the second line (or the whole complex diurnal equilibrium tide), and S the value of the third line (or semidiurnal equilibrium tide). Put 3sin‘/—1—E€=K; sin? cos7cosA\—C=Fecosf, sind coslsinX—D=Fsinf; cos’l cos2\—A=Geos2g, costsin2A—-B =Gsin2g. Then L=; aK BNO), ait ge telicséy fora iowi-nel mY ele) D=2ar sind cosé6.Fcos(~—f), . . . . . (IL) S=Fcos's.GeosQy—g),. . . . . . . (IL) where F, f, G, g are constants for each place, having different values for different places. Let ¢ be the angle between the body’s radius vector and the ascending node of its orbit relatively to the earth’s equator (which for the case of the sun will be his longitude); let » be the right ascension of this node (which for the case of the sun is of course zero); let a denote the right ascension of the body reckoned from this node (which for the sun will be his right ascension measured from the first point of Aries); let I denote the inclination of the body’s orbit to the plane of the earth’s equator (which for the case of the sun is nearly enough constant for our purposes and equal to 23° 27' 19"); lastly, let x denote the sidereal time reduced to angle, that is to say, the Greenwich hour-angle of the first point of Aries. We have ~=x-a-». 300 REPORT—1876. Hence by (I.) and (II.), D=2arF {cos (y¥—v—f) cosa+sin(y—v—f)sina}sindcosd, . . (IV.) 8 =FG {cos 2(x—v—g) cos 2a+sin 2(y-—v—g)sin2a}cos’e. . . . (V.) Now 6 and a are the two legs of a right-angled triangle of which ¢ is the hypotenuse and I the angle opposite to 6. Hence, by spherical trigonometry, sin 6=sin I sin 4, COs a COS O=COS ¢, sin a cos O=sin ¢ cos I. Hence sin*d= 43 sin*I(1—cos 2g), and so L=jarK(—2+sin*I—sin’*I cos29), . . . . . (VI) Next for the diurnal tide : sin 6 cos d6cos a=sin I sin ¢ cos ¢=} sin I sin 2¢, and sin 6 cos 6 sin a=sin Isin*p cos I=} sin I(1—cos 24) cos I; and using these in (IV.) we find (VII.), page 301. Similarly, towards reducing for the semidiurnal, cos 2a cos*d=(2 cos*a—1) cos*d = 2 cos*@ —(1 —sin’I sin’¢) =cos 24(1— sin*I)+ 3 sin*I=cos 29(3 +4 cos*I) + sin’l, and sin 2a cos*d=2 sin a Cos 6 cos a cos §=cos I sin 29. Using these in (V.) we find (VIII.), page 301. The sum of these three expressions (VI.), (VII.), and (VIII.), hi LDS os ot a ee would be the required complete simple harmonic expansion, if r were constant, and if ¢ increased simply in proportion to the time. To complete the process we must, by aid of physical astronomy, express 7 and @ in terms of x. For the case of the sun, the only deviation from uniform circular motion which produces sensible influence on the tides is the elliptic inequality ; for the case of the moon we must take into account also the perturbations called evection and variation. For the case of the sun we have rapes Teorrn0s 2... if E denote the earth’s mass, S the sun’s mass, p his parallax at any time, and w the obliquity of the ecliptic. Let P denote the mean parallax, w the longitude of the perihelion, and e the eccentricity of the orbit. As 9 now denotes the sun’s longitude, we have by the polar equation of the ellipse with one focus as pole, p=P{1+e cos (¢—@)} ; 1 do and by Kepler’s first law a is constant. iti \ Ra ae Mia 2 eae - {[@+0-Ca)e- Gq at De] agg + [C+ Oe-KG— 1s] wn 78 3 es ‘oat [te 9-004 C0 Get) | sexe } 29, Froori hat Gi eee tS Fae FRR ee cee { (6—X)g s00 agus #4+(4- oe x(G—1) Je #0 (8 —) 4 [(2- bg-O - X(G—a) sooo -(2+0¢— Og—X (Se— 2) )sooet+(4— O-X(Z-1))e s09 | ‘eae ne+ 2 { [(e+4-©-XG-1) meet +(2-F- KC +1) ms f+ Lu] 800+ (f— 3+* (Fe+1) us fans + : [(2-4- O-x (—1))mset+ (2+/-oe-* (j--1) sot —(f- Os—X(Fe- 1) a ]o7,s00 } urs T+ : { (o +X" )g soomuis — (2 - o+%7) 809 9g — UIs + — } ey md EH a “ (C2 De mires x 37) woh (v4 Os— Xe ~) us |.a= ~{@z O+%7) wo(v¥+Os-Xe —) ws 9g+(2- ©+X-) a (y¥+O¢- XE —) 800 94 — (vy+Oz¢- pe =—) us f= (yt+¢zg—) us .d (MITA) © 8 ttt [ B-4= Xe sors f+ (6—«—$—X)g 900 (B=) + (6-4-4 Ng 500 (= 8) | nZ =s a is eam aE ST A Gas asada sesh ae 302 REPORT—-1876. Hence if » denote the mean angular velocity of the sun’s radius vector, y the angular velocity of the earth’s rotation, and © the mean sun’s right ascension (or, which is the same, the sun’s “‘ mean longitude”) at the instant of the first transit of Y after the vernal equinox of the year, we have 7. = +e cos (¢—a)}? a 1+2¢ cos (g—@)} approximately =” { 1+42¢ cos (2 x+O -2) \ approximately, Vv Henceforward y must denote the whole angle turned through by the earth’ from the instant of the first transit of Y across the meridian of Greenwich © after a time when the sun’s longitude was zero. Hence, integrating, o=Ot xt sin (2x+0-#). Now, if A denote any angle, sin (—2¢+ = = sin( — —20 —-— “ly +A.) —de cos (-20-— ——x +A) sin (2x+ O- =) approximately : and therefore as p=? E + de cos (2 —— “)| approximately. . . . (XI) we have (XII.) (see page 301). Going back now to (VI.), (VII.), and (VIII.), and attending to (X.), use (XI.) in the first term of (VI.) and the last term of (VII.); neglect the variation of parallax and put =] x+© in the small terms of (VJ.), (VII.), and (VIII.); use (XI1.) in the first terms of (VII.) and (VIIL.), giving to A the q 7 respective values y—f and 5+2(x— g); and collect as in (IX.): we find (XITT.), (page 301). To obtain the corresponding expression for the moon’s equilibrium tide, substitute in the preceding, h’ for h, M for S, P’ for P, I for w, é' for e, o for n, )—v for ©, wo —v for w, f+v for f, and g+y for g: M denoting the moon’s mass, y the right ascension of the ascending node of the moon’s orbit on the earth’s equator, ) the mean moon’s right ascension at the time of that transit of Y across the meridian of Greenwich from which x (as stated above) is reckoned, a’ the longitude of the moon’s perigee, ¢ the mean angular TIDAL OBSERVATIONS. 803 velocity of the moon’s radius vector, and e’ the eccentricity of her orbit. With these explanations, it is better not to write out the formula, but rather to refer to (XIII.). But to complete the harmonic expression of the lunar equilibrium tide, so far as practically useful, we must include terms resulting from evection and variation, Mr. Roberts haying, in working out the harmonic analysis of the Liverpool tides for the Committee, discovered very sensible effects of these perturbations of the moon’s motion, and haying thenceforward analyzed for them regularly in every case in which the data were sufficiently complete. The only term of (VI.), (VII.), or (VIII.) having evectional and variational constituents which can be sensible in North-Atlantic ports is the chief semidiurnal tide represented by the first term of (VIII.). For other seas than the North Atlantic, the evectional and variational constituents of the two chief lunar diurnal tides represented by the first and last terms of (VII.) may be quite sensible; but it is not worth while at present to work out the equilibrium-values of these constituents ; it is enough to give the equilibrium- values of the evectional and variational perturbations of the chief semidiurnal tide, as it is only for these effects of evection and variation that the reductions hitherto performed give the data for comparison with observation. The theoretical expressions for the effects of evection and variation on the moon’s coordinates are :— Eyvection. Variation. On longitude. 18" ¢' sin[2(¢'+1—9)—(¢' +»—a’)]; 2 1) sin 2(9'+v—¢). Cc On parallax . P15 ¢' cos[2(p'+v—¢)—(¢' +) ]5 »(") cos 2(9'+ v—@). o o In these expressions substitute for g'+y and ¢ their approximate values, eytyp and "x+O Y Pe use the results in the first term of (VIII.) modified to suit the moon; and work out according to (XI.) and (XII.). Thus we find, for the evectional and variational semidiurnal tides, the equation (XIV.), page 301,] In I. and II. of the following Tables, the coefficient (R), speed (n), and epoch (e) of each of the simple harmonic terms of (XIII.) are given separately for convenience of reference. Table I. contains the values of these quantities for the case of the sun’s equilibrium tide; Table II. those for the moon’s equilibrium tide, with the addition of the evectional and variational consti- tuents of the semidiurnal tides. 304 REPORT—1876. TasreE I. T=3 = Pia =24-6746 (a being taken in centimetres). a8 | ss oh R+T. N. é. 22 term. 1 =aK 0 0 2. 1K sin? w 0 0 3. 1Ke n 180°-@+a 4, 1K sin? w 2Qn 180°—2© Fol F sin w cos? 3 y—2n f+270°+20 6. t¥Fe sin w cos? 3w y—3n f+270°+36 -—a@ ‘i 3¥e sin w cos? 4 y- n f+ 90°+O+a 8. F sin w sin? Jw y+2n f+ 90°—20 Klis F sin w cos w y f+ 90° 10. 3¥Fe sin w cos w y+ n f+90°-O+a i 3¥e sin w cos w y-— 7 f+90°+O-a@ 8.) 12. 20(- see = aaa 29 +20 T.| 13.) 4Ge = “) 2y —3n 2943Q—m R.|14.| 3Ge (=> “) Q2y—» | 29+180°+O+e 16.| 46(——S"") Ay+ n) | 29-20 K.|16.| 3G@sin?w Qy 29 TIDAL OBSERVATIONS. 305 Taste IT. T’=3™ py 53-6045. 2E 22 No. 7 a ores ree of R+T’ n. €. a * lca I. —iK 0 2. 3K sin? I 0 3. 4Ke' a 180°— p+’ 4. 3K sin? I 20 180°—2) +2y 5. F sin I cos? 31 y—20 F+270° 42) -y 6. £F¥e’ sin I cos* 31 y—30e f4+270°+3) —v—a' hs 4Fe' sin I cos? 31 y- 0 f+ 90°+ )-—v4a' 8. F sin I sin? 31 y+2e f+ 90°—2)y +2r 9. F sin Lcos I y F+ 90° +7 10. 3¥e' sin I cos I ae & f+ 90°—p+y+a' ile 3¥e' sin I cos I y- a f+ 90°+ )+yv-—a7 2 12. 16 *) Ay— 0) 2g+2y 1 1Ge' (+3) y—3e 29+3)—' 14). 4G (+3 =i Qy— a 29+180°+ p +a! a} ae(=S2) bot | oper 16. qG sin? I 2y 29+ 2r fl Ty 17.| 22Ge CS) 4 Qy— ¢—2Qn |2g94+180°+ ) +20—e' 1 if 18. | “39 Ge ( ae iE: - 2y—30+2n | 29+3)—20+4+7' bil I 19.| 4G (=3 ee ae? ;' Xy—n) 29 +20 fl FE 20, a a Ee y(2 2)" Ay—2e+n) | 29+2(2)—O) 1876. 306 REPORT—1876. In the following Tables (I’) and (II') the numerical values of R, so far as they can be calculated, and of n are given. Table (I') corresponds to Table (1.); (II') to (III.) In Table (II’) two values of R bracketed together are given for each term—one for the mean maximum value of I, and the other for the mean minimum value of I. These values of I are taken as 28° 36’ 7” and 18° 18’ 31"' respectively. TaBLE (I'). T=! : P'a= 24-6746. Distin- | No. n. ae eee ae vcr nanos 1. aK 0 Ba 0396 K 0 “heal 008385 K 0410686 ‘| -0396 K | 0821372 ea ae ae 3816 F | 14-9589314 6. 0224 F 14-9178628 i, 0082 F 15 8. 01644 F 151232058 K. 9. 3651 F 150410686 ; 10. 009185 F 15-0821372 i 009185 F 15 S. 12. 4595 G 30 T 13. 02697 G 29:9589314 R. 14. 003853 G 30:0410686 15. 0008534 G 30°1642744 K. 16. 0396 G 30-0821372 TIDAL OBSERVATIONS. 307 Taste (II’). T’=3 : P'q= 53-6045. Distin- | _ n. Be | tern, a is Me epg tes "he a ae oa ae 0 Lo | (gue ; 3. { Nae 0-5490165 4. { petites 1-0980330 0. 5 { Saee 13-9430358 Q. 6 { pe 13:3940191 7. { levee 144920521 8, { Ca anit 161391016 K. 9 { Bee 15-0410686 J 10. { Neti 155900851 11. { bese 14-4920521 M. 12, { vate 28-9841042 13. { Steete 28-4350877 if 14, { ete 29-5331207 ie { peta 31-1801702 K 16. { ee 30-0821372 r 17. { ogeias Gi 29-4509835 . 18. { aoeeiee 285172249 S. 19. { ee 30-0000000 ” 20. 1 ERE Ce 27-9682084 ns x2 308 REPORT—1876. Third Report of the Committee, consisting of Dr. Brunton, F.R.S., and Dr. Pyr-Smita, appointed to investigate the Conditions of Intestinal Secretion and Movement. Tux first part of the task of your Committee respected the comparative effect on intestinal secretion of various salts locally applied, and the action of other drugs, either mingled with these or injected into the blood, in modify- ing their action. This was completed in our first Report, in which we gave an account of our experiments on the local action of purgative salts, and stated that atropia has not the same inhibitory effect on intestinal secretion which it has on that of the submaxillary gland. Secondly, we ascertained last year that the same “ paralytic” secretion which Moreau observed in dogs and rabbits occurs under similar conditions in cats ; and, further, that this effect is not produced by division of the pneumogastric nerves and cervical sympathetic cord, nor by section of the splanchnics and spinal cord, and that all these sources of nervous supply may be cut off, and both semilunar ganglia extirpated, without paralytic secretion following. We ventured to anticipate that the inhibitory centre sought would be found in the smaller ganglia of the solar plexus. We had also noticed that hyperemia or hemorrhage of the intestinal mucous membrane does not follow either upon division of the splanchnics or upon extirpation of the lumbar portion of the spinal cord, but frequently occurs when both these operations have been performed together. This year your Committee have succeeded in proving positively that the conclusion they had reached by the method of exclusion is correct, namely, that the paralytic secretion of Moreau may be produced by extirpation of the smaller ganglia of the solar plexus, including those which are found in the superior mesenteric plexus. We have also ascertained that removal of these ganglia is rarely followed by hyperemia or hemorrhage of the intestinal mucous membrane, Thirdly, turning to the last section of our investigation, the movements of the intestine, we have obtained fairly conclusive evidence that its peristaltic movement (in the cat) is unaffected by irritation of the distal end of the divided splanchnies, but is called forth by stimulation of their proximal part. The conclusions, then, to which your Committee have been led may be thus summed up :-— 1. Application of various soda and potash salts to the intestinal mucous membrane produces a more or less profuse secretion, that caused by sulphate of magnesia, acetate of potash, sulphate of soda, and tartrate of potash and soda being most abundant. 2. The presence (in the intestine or in the blood) of atropia, morphia, chloral, &¢. does not prevent the above action of sulphate of magnesia. 3. The secretory nerves of the intestines have the small ganglia of the solar and superior mesenteric plexuses for their centres ; hence secretion is unaffected by section of the splanchnics, the vagi, or the dorso-lumbar part of the cord. 4. Destruction of the lumbar part of the cord, after extirpation of the solar plexus, produces hemorrhage or hyperemia of the intestinal mucous mem- brane, which is absent after division of the splanchnics, destruction of the ee ee Ol i i ae ON INTESTINAL SECRETION. 309 semilunar ganglia and solar plexus, or division of the mesenteric nerves themselves. 5. The splanchnic nerves are, as usually admitted, the vasomotor nerves of the intestines, but have no centrifugal fibres to their muscular coats, and can only indirectly affect them by diminishing their supply of blood. 6. The splanchnics are the afferent nerves which regulate peristalsis of the intestine, the efferent stimulus probably reaching its intraparietal ganglia through the lumbar cord and abdominal sympathetic. The following are the details of the experiments made this year. With those described in our two preceding Reports, they make up a total of more than a hundred, as the basis of the above conclusions. In the first series we continued and completed the experiments in our last Report, undertaken to ascertain the nervous centre, separation from which produces the “ paralytic” secretion of Moreau. Starting from the negative results with which we concluded our research last year, it will be seen that, of the thirteen cases in which we removed the solar or the superior mesenteric plexus, paralytic secretion resulted abundantly in Nos. 1, 2, 3, and 18, where both were removed. The same effect was produced in Nos. 7, 8, and 10, where the splanchnics and semilunar ganglia were left intact, and only the smaller (inferior) ganglia of the solar plexus, with the superior mesenteric offset from it, were excised. In No. 5, and also in No. 14, the paralytic secretion was likewise present, though less abundant. In four cases (Nos. 4, 6, 9, and 11) there was little or none; but in three of these cases the dissection, by which we verified in each case the completeness of the lesion produced, showed that the plexus had only been torn away from the artery without complete excision of its ganglia ; and in No. 11 the superior mesenteric plexus was simply cut across, so as to separate it from the semi- lunar ganglia and splanchnics, with the superior part of the solar plexus. Thus the negative results here, like those of last year’s experiments, confirm our present conclusions. In No. 12 there was enough fluid found to fill the loop moderately, but the rest of the intestine was empty: dis- section did not show any defect in the previous operation, nor had there been hemorrhage, diarrhoea, or sickness. It will, however, be noted that in this experiment less time had elapsed than in any of the others (2 instead of 32, 4, 5, or 6 hours); and this fact, taken with the observation of the most abundant secretion having followed the longest period between the excision of the plexus and the animal being killed (see No. 7), may perhaps explain the scanty secretion in this instance. The concluding series of experiments are on a difficult subject, which has already engaged the attention of Ludwig and his pupils, of Lister, Piluger, Wundt, Von Basch, and other distinguished physiologists. Whether we are justified in the conclusions which we have drawn we must wait for time to determine, and will only add that we are well aware of the many possible fallacies which attend the inquiry, as well as of the conflicting results of previous investigators. P.S.—Since this Report was presented (Glasgow, 1876), one of us, who was fortunate in securing the requisite Certificate from the Home Office, has obtained fresh results confirming those of the second series of these experi- ments.—July 1877. 310 REPORT—1876. SUMMARY OF EXPERIMENTS *. First Series. No. Lesicn. 1. | Excision of both semilunar gan- glia and of the superior mesen- teric plexus. Two 4-inch loops ligatured at beginning of je- junum and at end of ileum. 2. |Sameasl. Superior mesenteric artery accidentally wounded and ligatured. Diarrhoea before end of operation. Loops empty before ligature. 3t. | Same as 1 Result. Decreerare Upper loop empty ; mucous mem- brane dry. Between the loops 20 c.c. of mucus and serum without bile or blood ; mucous membrane moist. Lower loop contained a little of the same. Serous coat congested. CS ee Cat vomited shortly before it was killed. Peritoneal congestion of intestines. Duodenum, mucous membrane congested, hsmor- rhage into the gut. Upper loop, 5 ¢. ¢. of pale opalescent fluidt. Between the loops 40 c.c. of similar but rather thicker fluid, with a few streaks of blood which was accidentally mixed with it. Lower loop, 8 ¢. ec. of thin glairy fluid. Mucous mem- brane congested throughout. 4,........| Upper loop, 8 ¢. ¢. of bile-stained fluid. Between loops, 45 ¢. c. of turbid fluid. Lower loop, & c. ¢. of clear glairy fluid. Mucous membrane normal. 4. | Mesenteric plexus alone excised. | 3-4...... All the loops empty, except a tape- in jejunum ; middle and lower ileum tied. worm in the ileum. Mucous membrane pale. [On dissection, it was found that the operation had been very imperfectly per- formed, so that the greater part of the plexus was intact. | D: Same as 4. Three 4-inch loops} 4......... Duodenum partly contracted, with some fluid contents. Upper loop, Tc. ¢. of fluid. Middle, 5 e.c., with small tapeworm. Lower, 4 c.c. (darker) and a tapeworm. Intestine injected _ outside throughout ; mucous membrane in upper loop injected, in the others normal. * The animals used throughout were cats, and the anxsthetic employed was chloroform. t The laboratory assistant, who had been a soldier in India, remarked that this fluid was just like the rice-water stools he had seen in cholera epidemics, { This cat was white, with grey eyes, and was deaf. a ree Tg ON INTESTINAL SECRETION. 311 TABLE (continued). Sameas4. ‘Two loops tied; one in upper jejunum 8 in., the other in lower ileum 6 in. Same as 4, | Same as+. One loop tied in lower ileum 18 in, Lacteal full. Superior mesenteric divided from the solar plexus, but no ganglia removed. | Superior mesenterie plexus di- vided, and both semilunar ganglia excised. Solar plexus excised. Superior mesenteric artery isolated by excision of its plexus. Three loops as in No. 5. | Result. Upper loop, tapeworm and round worms. Middle empty. Lower, tapeworms. Mucous membrane pale and bile-stained. [The superior mesenteric plexus was found to have been only de- tached without excision. | Upper loop, a little clear fluid. Between loops, 52 c. c. of yel- lowish, rather turbid and tena- cious fluid. Lower empty. Mu- cous membrane pale. No worms. Serous coat injected. Upper loop, 21 ¢. ¢. of turbid and blood-stained fluid; tapeworm and round worms. Between loops, 28 ¢. ¢. of similar fluid ; no worms. Lower loop, 22 ¢. c. of serous fluid ; no worms. Mu- cous membrane pale throughout, and viscera anzmic. The whole intestine empty. Mu- cous membrane dry. One small tapeworm. Clot in peritoneum from oozing of a small vessel. [Some of the plexus was found only separated from the artery, but not destroyed. | Jejunum and upper ileum (25 in.), 27 ¢. ce. yellow turbid fluid. Loop 45 c. c. same fluid. Mu- cous membrane rather pale. No worms. Congested exter- nally, and serous effusion in peritoneum. Negative result. |. | | | ' | Only a few ec. c. of glairy fluid in the loop. The cat was sick during the night, and passed mucous stools. After it was killed next morning there was no peritonitis found, but ef- fusion of chyle from puncture of a lacteal during the operation. Upper loop filled with dark brown fluid. Middle the same, but not so abundant. Lower, as upper. Mucous membrane pale, cedema- tous, and covered with thin te- nacious mucus. ‘Two round worms and a tapeworm. 312 REPORT—1876. Srconp SERrEs. 14.—Cat under chloroform. Abdomen opened, and intestines exposed for 5 or 6 minutes to the air. No movement, The interrupted current from DuBois Reymond’s induction-coil was used in this and the succeeding ex- periments. Electrodes placed under left splanchnic. Secondary coil at 25, no effect; at 15, doubtful; at 10, rapid aneemia of stomach and small intes- tines and of a large mesenteric gland. No movement. Coil at 7: con- tinued anemia, which now extended to the kidneys; no movement; after removal of the irritation, the anemia continued and even increased for a short time in the intestines, the kidneys recovering their normal vascularity more quickly. After the intestines had regained their normal vascularity, the coil was put at 5, and the left splanchnic again irritated for 5 minutes. The etfect was the same, but much less decided than before. After the current was stopped, the intestines became rapidly hyperemic. The irritation once more applied, with the coil at 0, anemia only ensued after 30 seconds. No movement of the intestines. Ten minutes later the current was applied to the right splanchnic with the secondary coil at 25: no effect. Coil moved to 15: anemia of stomach and intestines ; slight movement, which had begun before the first irritation, now ceased. Current stopped: normal vascularity recovered ; peristalsis began again, and became rather active; ecchymosis apparent under the tunic of the right kidney. Intestines at rest: vascularity normal. Right splanchnic irritated with coil at 10: after two minutes, anemia of stomach and some coils of intestine. Moved to 5, the large arteries became evidently smaller, though the vascularity of the viscera was still only partially affected. After two minutes more no movement. The solar plevus, including the semilunar ganglia, was now eacised, and the superior mesenteric artery isolated. The intestines were somewhat hyper- eemic, the kidneys normal, peristalsis rather active. An upper and lower loop of 8 in. each ligatured as before. Coil at 15: electrodes applied to both splanchnics so as to irritate them at the same time: no anemia; movement slightly increased. Coil at 10: no anemia; movement considerably increased. Coil at 5: active peristalsis of stomach and intestines, doubtful decrease of vascularity. The left splanchnic was next divided, and the electrodes applied to its proximal end, with the coil at 25. The movements which were going on before continued active, while the coil was moved to 15, 10, and 5. Slight anemia appeared with the coil at 15, and did not increase. After the current was stopped, the intestines continued their movements, and quickly recovered a normal or perhaps slightly excessive vascularity. Fresh irrita- tion a few minutes later (of the proximal end of the left splanchnic) produced no change in vascularity or in movement of the intestine. The cat died several hours later without having vomited. ‘The greater part of the small intestine contained only a moderate quantity of fluid, but the lower loop was filled with serum and thick white mucus. No worms. On dissection the right semilunar ganglion and solar plexus adjacent were found to be imperfectly removed: otherwise the operation had succeeded. 15.—Cat under chloroform. Abdomen opened and electrodes put on the left splanchnic, with coil at 25: no peristalsis, moderate injection. Current on: at first apparent slight increase of vascularity, but when the coil was moved to 15, pallor, with contraction of the branches of the superior mesen- ON INTESTINAL SECRETION. 313 teric artery, became marked. No movement of stomach or intestines took lace. j 16.—Cat chloroformed and put into a bath of -75 per cent. salt solution at 90° to 100° F., with the trachea opened so as to allow of complete immer- sion*. After electrodes had been put on both splanchnics, with the intestines at rest and moderately injected, the current was put on with a commutator, so as to pass through both nerves at once with the coil at 25, shifted after two minutes to 15, and then to 5 and to 0, but without visible effect. 17.—Cat chloroformed and abdomen opened. Intestines pale. Pregnant uterus. No peristalsis. Both splanchnies divided. Proximal end of right irritated, with the coil at 25. After two minutes the uterus began moving: on breaking the circuit this ceased gradually. The same occurred on applying the electrodes in the same way to the left splunchnic, the intestines still re- maining motionless and their injection not varying. The narcosis was kept only moderately deep, the tail constantly moving. At every third or fourth expiration there was a strong contraction of the abdominal walls with relaxed diaphragm (effort at vomiting). Electrodes were then applied to (the proximal end of) both splanchnics, and the current passed through both at once. Coil at 25: nochange: intes- tines drawn out from abdomen so as to bring the greater part into view; they were motionless and moderately vascular. Coil at 15, current on: active peristalsis began, and soon spread to all the small intestines ; the uterus also moved as before ; vascularity of the viscera not altered. After three minutes the current was stopped, and the movements quickly ceased. Repeated with the coil at 5 and at 10 no effect was produced, but general movements of the voluntary muscles ensued from escape of the current. The animal was then placed in a bath of -75 per cent. of salt solution at about 90° F., arranged so as to cover the abdomen but allow of respiration, and both splanchnies were irritated with the coil at 10: no effect. Removed from bath: no movement. Left splanchnic (proximal end as before) irritated with coil at 15. After 30 seconds active peristalsis began in the colon, the uterus, and some folds of the small intestine. Moved to 10, peristalsis appeared in fresh folds, which ceased on stopping the current. Electrodes on right splanchnic: coil at 15: no movement. Current on: after a few seconds active peristalsis began in the stomach, spread to the intestines,'and by the end of the first minute all the small intestines were in movement, as well as the uterus, the colon not participating. Moved up to 10, increased activity of motion, the colon continuing quiet, and the vascu- larity of the viscera not affected, except as the tight contraction of the gut produced transient pallor. On stopping the current, peristalsis ceased within two minutes. The electrodes were then applied to the superior mesenteric plecus, which was isolated for the purpose. Coil at 15, current on: slight movement occurred, but not constantly; the vascularity of the small intestine was distinctly, though only moderately diminished. Applied to the renal plewus no change was visible, but after removal the kidney increased in vascularity. Applied lastly to the nerves going to the spleen, that viscus shrunk from 53 to 5 inches in length. 18.—Cat under chloroform. Both splanchnics divided, and distal end of left placed on electrodes, the intestines being anemic and at rest. Coil at 25, current on: after 90 seconds there was very slight and limited peri- * This precaution (in which we followed Sanders Ezn and Houckgeest) we found to be useless for the object in view, and do not recommend it to future investigators. 314 REFORT—1876. stalsis, but no other change. With the coil at 15 there was no movement, but the intestines were more vascular than before, which may, however, have been due to sponging with warm water to remove some blood. Experiment repeated with the animal in the bath. There was then no change in vascularity, and no movement, except very slight peristalsis in a single coil. (This cat had suffered from hemorrhage, owing to the liver being bruised in restoring it by artificial respiration. The fact was discovered after the animal was killed, and explained its feeble state during the experiments.) 19.—Cat chloroformed. Both splanchnics divided. Electrodes placed on proximal end of left, and the animal immersed in the bath at 100° F. There was at first active peristalsis, and after this had ceased, stimulation, with the coil at 25, produced no effect on the vascularity or movement of the intes- tines. Repeated out of the water there was still no movement, but the in- testines became less vascular while the current passed, and then somewhat hyperemic. Stimulation of the proximal end of the right splanchnic out of the bath produced active peristalsis. The vascularity varied irregularly, and probably independently, with moderate injection after the current was stopped. On the left splanchnic being again irritated after an interval (with the coil still at 25), peristalsis, which had become very languid, was distinctly in- creased. The intestines became pale during the strong contraction of each coil, but otherwise their vascularity was unaffected. Stimulation of the splenic plewus reduced the length of the spleen from 3} to 33 inches. Report of the Commitiee, consisting of A. Vernon Harcourt, Professor Guapstonr, and Dr. ArKinson, appointed for the purpose of collect- ing and suggesting subjects for Chemical Research. Brrore entering upon the task of forming a list of subjects, the members of the Committee took opportunities of discussing the question privately with other chemists, and found in many cases considerable doubts as to the advisability of such a proceeding. Instead, therefore, of at once inviting suggestions for research, the Committee considered it desirable to ascertain the opinion of English chemists generally as to the feasibility of the proposed scheme. The following Circular was accordingly sent to about fifty chemists, who were either those of the highest official standing, or who were known to be engaged in research :— “‘ British AssocIaTION FOR THE ADVANCEMENT OF SCIENCE. “ April 24, 1876. “Dear Str,—At the last Meeting of the British Association a Committee was appointed, consisting of Mr. Vernon Harcourt, Dr. Gladstone, and Dr. E. Atkinson, with power to add to their number, to collect and suggest subjects for chemical research. “When the matter was discussed by the Committee of the Chemical Section, at whose instance the above-named Committee was appointed, it was thought that a step might be taken towards the organization of chemical inquiry by the for- aan ON CHEMICAL RESEARCH. 315 mation and publication of a list of subjects to be suggested by the leading chemists of our own country, and, if possible, of other countries also, from which younger chemists wishing to derek a research might select a subject with the assurance that it was considered new and important. “Tt was thought also that such a list, however meagre and inadequate it might be at the outset, would tend to increase as soon as the plan became more widely lmown, and might ultimately, if chemists of other countries were willing to take part, become an important feature in a general organization of chemical research. “A chemist undertaking the investigation of any one of the suggested subjects would send word to the editors of the list, and might be placed in communi- cation with the chemist by whom the subject was suggested. Each issue of the list, which might be republished at frequent intervals in some of the chemical journals, would state which subjects had been already undertaken and by whom, and thus the waste of labour which sometimes occurs through simultaneous work on the same subject would be prevented. “Tt has, however, been objected that chemists are not likely to be so prodigal of their ideas as such a scheme supposes, and may prefer keeping the subjects of research which have suggested themselves to their minds for their own or their pupils’ investigation. The answer to this would seem to depend upon the answer to the general question, whether the supply of ideas or suggestions for research existing in the minds of the leading chemists at the present day does or does not largely exceed the number of skilled hands at their disposal. “Before, therefore, proceeding to invite you and others to suggest subjects to be placed upon the proposed list, the Committee are desirous of learning whether in your judgment the scheme is likely to succeed, and whether, if the attempt to form such a list is made, you would be willing to contribute to it; they would also be glad of any opinions in reference to the matter with which you may favour them. “ We are, dear Sir, “ Yours faithfully, “A, G. Vernon Harcourt, “J. H. GuapsTong, “i, ATKINSON.” “PS. Please address your answer, Dr. Atkinson, York Town, Surrey.” To this Circular only eight written replies were received, of which four may be classed as favourable, namely, those from Mr. Abel, President of the Chemical Society, Prof. Mills, Mr. Bolas, and Mr. R. Warington; three as adverse to the scheme, viz. from Dr. Joule, Mr. Hartley, and Mr. Groves, the latter embodying the views of Dr. Stenhouse; and one as doubtful from Mr. Buckton. Among the objections raised to the proposed scheme perhaps the following have been the most general :— That suggestions for subjects of research would only be needed by, or be useful to, students and beginners, and that such men would generally be under the guidance of Professors, who would provide them with subjects; that the suggestion of a subject is generally its least part; that what students really want is guidance and instruction in the art of investigation ; that any one who had originality and power to make a satisfactory research would also be able to find subjects for himself; that facilities and material appliances for research, together with the means of living for those thus engaged, were more pressing wants; that any one contributing suggestions for research would reserve for his own use the best of them, that is to say, those most likely to give im- portant and satisfactory results. Of the letters received, the Committee may perhaps give the following from Mr. Buckton and from Dr. Joule :— 316 REPORT—1876. ‘“Wycombe, Haslemere. “‘T believe that the result of chemical inquiry would be greater and more important in nature if the suggestions made by your Committee could be efficiently carried out. I must confess, however, that my fears shape them- selves very much after the fashion expressed by paragraph 5 of your Circular. “ Original workers, I believe, always are under the hope that eventually time and opportunity will present themselves, so that they will allow them personally to work out their brightest and most promising ideas. If this be so, but few of such will find a place in the contemplated list. Again, hesita- tion might be felt amongst some lest the most promising subjects should be negatived by the results of an inexperienced hand. “The number of skilled hands in our laboratories is certainly larger than formerly, yet probably in this country latterly the harvest of original work has not been in due proportion to this number. “Tf so, the steps proposed towards the organization of chemical inquiry by way of a list will, I think, be beneficial. “G. B. Bucxron.” “Manchester, May 4, 1876. “We know that the scientific faculty is of slow growth in the case of any individual student. He becomes interested in a particular line of inquiry, and in pursuing it becomes further interested by the acquisition of new facts. The original inquiry will naturally ramify, and there will be a completeness about his work and also an accuracy which could not be expected from that done as it were to order. I think, too, that the mere suggestions of a research may tend to make it unpalatable to many minds. We know that mere sug- gestions have in some instances been claimed as discoveries. On this account many would feel some delicacy in even suggesting an inquiry, necessarily accompanied by the suggestion of the expected result, simply because it looks like a forestalling to some extent of the merit of the actual labourer. ‘*Then, in order to be in a position to suggest, a scientific man must have mentally worked out the methods and anticipated the results of the proposed train of investigation, and would doubtless prefer to work it out himself, or, at any rate, to have the work done by his pupils under his immediate super- intendence—first, because he naturally wishes that full justice should be done to the subject from his own point of view; and second, because he considers himself to a certain extent in the light of a proprietor. “‘T do not think it desirable to use any extra stimulus to induce students to work. If their own tastes and abilities and information do not lead them to find a vein of knowledge and work it, the application of such stimulus would probably result in the accumulation of incomplete and erroneous results to the hindrance of real scientific advancement. “ James P. JOULE.” In order that the proposed scheme should be successful it ought to meet with very general support. This has been far from being the case, and there- fore the Committee have not thought it advisable to proceed further in the matter. NOTICES AND ABSTRACTS OF MISCELLANEOUS COMMUNICATIONS TO THE SECTIONS. MATHEMATICS AND PHYSICS. ° Address by Professor Sir Witt1am Tuomson, LL.D., M.A., F.R.S., President of the Section. A CONVERSATION which I had with Professor Newcomb one evening last June, in Professor Henry’s drawing-room in the Smithsonian Institution, Washington, has forced me to give all my spare thoughts ever since to Hopkins’s problem of Preces- sion and Nutation, assuming the earth a rigid spheroidal shell filled with liquid. Six weeks ago, when I landed in England after a most interesting trip to America and back, and became painfully conscious that I must have the honour to address you here today, I wished to write an Address of which science in America should be the subject. I came home, indeed, vividly impressed with much that I had seen both in the Great Exhibition of Philadelphia and out of it, showing the truest scientific spirit and devotion, the originality, the inventiveness, the patient perseve- ring thoroughness of work, the appreciativeness, and the generous open-mindedness and sympathy, from which the great things of science come. * O6\w héyery ’Arpeioas OédrAw bE Kadpoy ade.” I wish I could speak to you of the veteran Henry, generous rival of Faraday in electromagnetic discovery; of Peirce, the founder of high mathematics in America ; of Bache, and of the splendid heritage he has left to America and to the world in the United-States Coast Survey ; of the great school of astronomers which followed —Gould, Newton, Newcomb, Watson, Young, Alvan Clarke, Rutherford, Draper (father and son) ; of Commander Belknap and his great exploration of the Pacific depths by pianoforte-wire with imperfect apparatus supplied from Glasgow, out of which he forced a success in his own way; of Captain Sigsbee, who followed with like fervour and resolution, and made further improvements in the apparatus by which he has done marvels of easy, quick, and sure deep-sea sounding in his little surveying-ship ‘ Blake ;’ and of the admirable official spirit which makes such men and such doings possible in the United-States Naval Service. I would like to tell you, too, of my reasons for confidently expecting that American hydrography will soon supply the data from tidal observations, long ago asked of our Govern- ment in vain by a Committee of the British Association, by which the amount of the earth’s elastic yielding to the distorting influence of sun and moon will be measured ; and of my strong hope that the Compass Department of the American Navy will repay the debt to France, England, and Germany, so appreciatively acknowledged in their reprint of the works of Poisson, Airy, Archibald Smith, 1876. aS 2 REPORT—1876. Evans, and the Liverpool Compass Committee, by giving in return a fresh marine survey of terrestrial magnetism, to supply the navigator with data for correcting his compass without sights of sun or stars. Can I go on to Precession and Nutation without a word of what I saw in the Great Exhibition of Philadelphia? In the U.S. Government part of it, Professor Hilgard showed me the measuring-rods of the U.S. Coast Survey, with their beau- tiful mechanical appliances for end measurement, by which the three great base- lines of Maine, Long Island, and Georgia were measured with about the same accuracy as the most accurate scientific measurers, whether of Europe or America, have attained in comparing two metre or yard measures. In the United-States telegraphic department I saw and heard Elisha Gray’s splendidly worked-out Electric Telephone actually sounding four messages simul- taneously on the Morse code, and clearly capable of doing yet four times as many with very moderate improvements of detail; and I saw Kdison’s Automatic Tele- graph delivering 1015 words in 57 seconds—this done by the long-neglected electro-chemical method of Bain, long ago condemned in England to the helot work of recording from a relay, and then turned adrift as needlessly delicate for that. In the Canadian Department I heard “To be or not to be...... there's the rub,” through an electric telegraph wire; but, scorning monosyllables, the electric articulation rose to higher flights, and gaye me passages taken at random from the New-York newspapers :—“ 8.5. ‘Cox’ has arrived ” (I failed to make out the 8.8. ‘Cox’); ‘the City of New York ;” “Senator Morton ;” “The Senate has resolved to print a thousand extra copies;” ‘The Americans in London have resolved to celebrate the coming fourth of July.” All this my own ears heard, spoken to me with unmistakable distinctness by the thin circular disk armature of just such another little eee as this which I hold in my hand. The words were shouted with a clear and loud voice by my colleague-judge, Professor Watson, at the far end of the telegraph-wire, holding his mouth close to a stretched membrane, such as you see before you here, carrying a little piece of soft iron, which was thus made to perform in the neighbourhood of an electromagnet in circuit with the line motions proportional to the sonorific motions of the air. This, the greatest by far of all the marvels of the electric telegraph, is due to a young countryman of our own, Mr. Graham Bell, of Edinburgh and Montreal and Boston, now becoming a naturalized citizen of the United States. Who can but admire the hardihood of invention which devised such very slight means to realize the mathematical con- ception that, if electricity is to convey all the delicacies of quality which di- stinguish articulate speech, the strength of its current must vary continuously and as nearly as may be in simple proportion to the velocity of a particle of air engaged in constituting the sound ? The Patent Museum of Washington (an institution of which the nation is justly proud) and the beneficent working of the United-States patent laws deserve notice in the Section of the British Association concerned with branches of science to which nine tenths of all the useful patents of the world owe their foundations. I was much struck with the prevalence of patented inventions in the Exhibition: it seemed to me that every good thing deserving a patent was patented. I asked one inventor of a very good invention, “* Why don’t you patent it in England? ” He answered, “The conditions in England are too onerous.” We certainly are far behind America’s wisdom in this respect. If Europe does not amend its patent laws (England in the opposite direction to that proposed in the Bills before the last two sessions of Parliament) America will speedily become the nursery of useful inventions for the world. I should tell you also of “ Old Prob’s” weather-warnings, which cost the nation 250,000 dollars a year: money well spent say the western farmers; and not they alone; in this the whole people of the United States are agreed ; and though Demo- crats or Republicans playing the “economical ticket ” may for half a session stop the appropriations for even the United-States Coast Survey, no one would for a moment think of proposing to starve “ Old Prob ;” and now that 80 per cent. of his probabilities have proved true, and General Myers has for a month back ceased to call his daily forecasts “ probabilities” and has begun to call theni indications, what will the western farmers call him this time next year? TRANSACTIONS OF THE SECTIONS. 3 And the United-States Naval Observatory, full of the very highest science, under the command of Admiral Davis! If, to get on to Precession and Nutation, I had resolved to omit telling you that I had there, in an instrument for measuring pho- tographs of the Transit of Venus shown me by Professor Harkness (a young Scots- man attracted into the United-States Naval Service), seen, for the first time in an astronomical observatory, a geometrical slide, the verdict on the disaster on board the ‘Thunderer,’ published while I am writing this address, forbids me to keep any such resolution, and compels me to put the question—Is there in the British Navy, or in a British steamer, or in a British land-boiler another safety-valve so con- structed that by any possibility, at any temperature or under any stress, it can jam ? and to say that if there is, it must be instantly corrected or removed. I ought to speak to you, too, of the already venerable Harvard University, the Cambridge of America, and of the Technological Institute of Boston, created by William Rogers, brother of my late colleague in this University (Glasgow), Henry Rogers, and of the Johns Hopkins University of Baltimore, which with its youthful vigour has torn Sylvester from us, has utilized the genius and working-power of Roland for experimental research, and three days after my arrival in America sent for the young Porter Poinier to make him a Fellow; but he was on his deathbed, in New York, “ begging his physicians to keep him alive just to finish his book, and then he would be willing to go.” Of his book, ‘Thermodynamics,’ we may hope to see at least a part, for much of the manuscript and good and_able friends to edit it are left; but the appointment to a Fellowship in the Johns Hopkins University came a day too late to gratify his noble ambition. But the stimulus of intercourse with American scientific men left no place in my mind for framing or attempting to frame a report on American science. Dis- turbed by Newcomb’s suspicions of the earth’s irregularities as a time-keeper, I could think of nothing but precession and nutation, and tides and monsoons, and settlements of the equatorial regions, and meltings of the polar ice. Week after week passed before I could put down two words which I could read to you here today; and so I have nothing to offer you for my Address but Review of Evidence regarding the Physical Condition of the Earth: its internal Temperature; the Fluidity or Solidity of its interior Substance ; the Rigidity, Elasticity, Plasticity, of its External Figure; and the Per- manence or Variability of its Period and Awis of Rotation. The evidence of a high internal temperature is too well known to need any quo- tation of particulars at present. Sutfice it to say that below the uppermost ten metres stratum of rock or soil sensibly affected by diurnal and annual variations of temperature there is generally found a gradual increase of temperature downwards, approximating roughly in ordinary localities to an average rate of 1° Centigrade per thirty metres of descent, but much greater in the neighbourhood of active vol- canoes and certain other special localities, of comparatively small area, where hot springs and perhaps also sulphurous vapours prove an intimate relationship to vol- canic quality. It is worthy of remark in passing that, so far as we know at present, there are no localities of exceptionally small rate of augmentation of underground temperature, and none where temperature diminishes at any time through any con- siderable depth downwards below the stratum sensibly influenced by summer heat and winter cold. Any considerable area of the earth of, say, not less than a kilo- metre in any horizontal diameter, which for several thousand years had been covered by snow or ice, and from which the ice had melted away and left an average surface temperature of 13° Cent., would, during 900 years, show a decreasing temperature for some depth down from the surface; and 3600 years after the clearing away of the ice would still show residual effect of the ancient cold, in a half rate of aug- mentation of temperature downwards in the upper strata, gradually increasing to the whole normal rate, which would be sensibly reached at a depth of G00 metres. By a simple effort of geological calculus it has been estimated that 1° yer 30 metres gives 1000° per 30,000 metres, and 3333° per 100 kilometres. This aith- metical result is irrefragable; but what of the physical conclusion drawn from it A REPORT—1876. with marvellous frequency and pertinacity, that at depths of from 30 to 100 kilo- metres the temperatures are so high as to melt all substances composing the earth’s upper crust? It has been remarked, indeed, that if observation showed any dimi- nution or augmentation of the rate of increase of underground temperature in great depths, it would not be right to reckon on the uniform rate of 1° per 30 metres or thereabouts down to 30 or 60 or 100 kilometres. “ But observation has shown nothing of the kind ; and therefore surely itis most consonant with inductive philo- sophy to admit no great deviation in any part of the earth’s solid crust from the rate of increase proved by observation as far as the greatest depths to which we have reached!” Now I have to remark upon this argument that the greatest depth to which we have reached in observations of underground temperature is scarcely one kilometre; and that if a 10-per-cent. diminution of the rate of augmentation of underground temperature downwards were found at a depth of one kilometre, this would demonstrate * that within the last 100,000 years the upper surface of the earth must have been at a higher temperature than that now found at the depth of one kilometre. Such a result is no doubt to be found by observation in places which have been overflown by lava in the memory of man or a few thousand years further back; but if, without going deeper than a Kilometre, a 10-per-cent. diminution of the rate of increase of temperature downwards were found for the whole earth, it would limit the whole of geological history to within 100,000 years, or, at all events, would interpose an absolute barrier against the continuous descent of life on the earth from earlier periods than 100,000 years ago. There- fore, although search in particular localities for a diminution of the rate of aug- mentation of underground temperature in depths of less than a kilometre may be of intense interest, as helping us to fix the dates of extinct volcanic actions which have taken place within 100,000 years or so, we know enough from thoroughly sure geological evidence not to expect to find it, except in particular localities, and to feel quite sure that we shall not find it under any considerable portion of the earth’s surface. If we admit as possible any such discontinuity within 900,000 years, we might be prepared to find a sensible diminution of the rate at three knlometres depth; but not at any thing less than 30 kilometres if geologists validly claim as much as 90,000,000 of years for the length of the time with which their science is concerned. Now this implies a temperature of 1000° Cent. at the depth of 30 kilo- metres, allows something less than 2000° for the temperature at 60 kilometres, and does not require much more than 4000° Cent. at any depth however great, but does require at the great depths a temperature of, at all events, not less than about 4000° Cent. It would not take much “ hurrying up ” of the actions with which they are concerned to satisfy geologists with the more moderate estimate of 50,000,000 of years. This would imply at least about 3000° Cent. for the limiting temperature at great depths. If the actual substance of the earth, whatever it may be, rocky or metallic, at depths of from 60 to 100 kilometres, under the pressure actually there experienced by it, can be solid at temperatures of from 3000° to 4000°, then we may hold the former estimate (90,000,000) to be as probable as the latter (50,000,000), so far as evidence from underground temperature can guide us. If 4000° would melt the earth’s substance ata depth of 100 kilometres, we must reject the former estimate though we might still admit the latter; if 3000° would melt the substance at a depth of 60 kilometres, we should be compelled to conclude that 50,000,000 of years is an over-estimate. Whatever may be its age, we may be quite sure the earth is solid in its interior; not, [ admit, throughout its whole volume, for there certainly are spaces in volcanic regions occupied by liquid lava ; but whatever portion of the whole mass is liquid, whether the waters of the ocean or melted matter in the interior, these portions are small in comparison with the ~ whole; and we must utterly reject any geological hypothesis which, whether for explaining underground heat or ancient upheavals and subsidences of the solid crust, or earthquakes, or existing volcanoes, assumes the solid earth to be a shell of 80, or 100, or 500, or 1000 kilometres thickness, resting on an interior liquid mass. * For proof of this and following statements regarding underground heat, I refer to “ Secular Cooling of the Earth,” Transactions of the Royal Society of Edinburgh, 1862; and Thomson and Tait’s ‘ Natural Philosophy,’ Appendix D, TRANSACTIONS OF THE SECTIONS. 5 This conclusion was first arrived at by Hopkins, who may therefore properly be called the discoverer of the earth’s solidity. He was led to it by a consideration of the phenomena of precession and nutation, and gave it as shown to be highly probable, if not absolutely demonstrated, by his confessedly imperfect and tentative investigation. Buta rigorous application of the perfect hydrodynamical equations leads still more decidedly to the same conclusion. I am able to say this to you now in consequence of the conversation with Pro- fessor Newcomb, to which I have already alluded. Admitting fully my evidence for the rigidity of the earth from the tides, he doubted the argument from preces- sion and nutation. Trying to recollect what I had written on it fourteen years ago in a paper on the “ Rigidity of the Karth,” published in the Transactions of the Royal Society, my conscience smote me, and I could only stammer out that I had convinced myself that so-and-so and so-and-so, at which I had arrived by a non- mathematical short cut, were true. He hinted that viscosity might suffice to render precession and nutation the same as if the earth were rigid, and so vitiate the argument for rigidity. This I could not for a moment admit, any more than when it was first put forward by Delaunay. But doubt entered my mind regarding the so-and-so and so-and-so; and I had not completed the night journey to Phila- delphia which hurried me away from our unfinished discussion before I had con- vinced myself that they were grievously wrong. So now I must request as a favour that each one of you on going home will instantly turn up his or her copies of the ‘Transactions of the Royal Society’ for 1862 and of Thomson and Tait’s ‘ Natural Philosophy,’ vol. i., and draw the pen through §§ 23-31 of my paper on the “ Rigidity of the Earth” in the former, and through every thing in §§ 847, 848, 849 of the latter which refers to the effect on precession and nutation of an elastic yielding of the earth’s surface. When those passages were written I knew little or nothing of vortex motion ; and until my attention was revalled to them by Professor Newcomb I had never once thought of this subject in the light thrown upon it by the theory of the quasi- rigidity induced in a liquid by vortex motion, which has of late occupied me so much. With this fresh light a little consideration sufficed to show me that (although the old obvious conclusion is of course true, that, if the inner boundary of the imagined rigid shell of the earth were rigorously spherical, the interior liquid could experience no precessional or nutational influence from the pressure on its bounding surface, and therefore if homogeneous could have no precession or nuta- tion at all, or if heterogeneous only as much precession and nutation as would be produced by attraction from without in virtue of non-sphericity of its surfaces of equal density, and therefore the shell would have enormously more rapid precession and nutation than it actually has—forty times as much, for instance, if the thickness of the shell is 60 kilometres) a very slight deviation of the inner surface of the shell from perfect sphericity would suffice, in virtue of the quasi-rigidity due to vortex motion, to hold back the shell from taking sensibly more precession than it would give to the liquid, and to cause the liquid (homogeneous or heterogeneous) and the shell to have sensibly the same precessional motion as if the whole constituted one rigid body. But it is only because of the very long period (26,000 years) of pre- cession, in comparison with the period of rotation (one day), that a very slight deviation from sphericity would suffice to cause the whole to move as if it were a rigid body. A little further consideration showed me :— (1) That an ellipticity of inner surface equal to oii but that an ellipticity of one or two hundred times this amount would not be too small to compel approximate equality of precession throughout liquid and shell. would be too small, (2) That with an ellipticity of interior surface equal to ano» if the precessional motion were 26,000 times as great as it is, the motion of the liquid would be very different from that of a rigid mass rigidly connected with the shell. (3) That with the actual forces and the supposed interior ellipticity of an the lunar nineteen-yearly nutation might be affected to about five per cent. of its amount by interior liquidity, 6 REPORT—1876. (4) Lastly, that the lunar semiannual nutation must be largely, and the lunar fortnightly nutation enormously affected by interior liquidity. But although so much could be foreseen readily enough, I found it impossible to discover without thorough mathematical investigation what might be the cha- racters and amounts of the deviations from a rigid body’s motion which the several cases of precession and nutation contemplated would present. The investigation, limited to the case of a homogeneous liquid enclosed in an ellipsoidal shell, has brought out results which I confess have greatly surprised me. When the interior ellipticity of the shell is just too small, or the periodic speed of the disturbance just too great to allow the motion of the whole to be sensibly that of a rigid body, the deviation first sensible renders the precessional or nutational motion of the shell smaller than if the whole were rigid, instead of greater, as I expected. The amount of this difference bears the same proportion to the actual precession or nutation as the fraction measuring the periodic-speed of the disturbance (in terms of the period of rotation as unity) bears to the fraction measuring the interior ellipticity of the shell; and it is remarkable that this result is independent of the thickness of the shell, assumed, however, to be small in proportion to the earth’s radius. Thus in the case of precession the effect of interior liquidity would be to diminish the periodic speed of the precession in the proportion stated ; in other words, it would add to the precessional period a number of days equal to the multiple of the rotational period equal to the number whose reciprocal measures the ellipticity. Thus, in the actual case of the earth, if we still take a as the ellipticity of the inner boundary of the supposed rigid shell, the effect would be to augment by 300 days the pre- cessional period of 2600 years, or to diminish by about a the annual precession of about 51", an effect which I need not say would be wholly insensible. But on the lunar nutation of 18-6 years period, the effect of interior liquidity would be quite sensible; 18-6 years being twenty-three times 500 days, the effect would be to diminish the axes of the ellipse which the earth’s pole describes in this period each by a of its own amount. The semiaxes of this ellipse, calculated on the theory of perfect rigidity from the very accurately known amount of precession, and the fairly accurate knowledge which we have of the ratio of the lunar to the solar part of the precessional motion, are 9'-22 and 6''86, with an uncertainty not amounting to one half per cent. on account of want of perfect accuracy in the latter part of data. If the true values were less each by x of its own amount, the dis- crepance might have escaped detection, or might not have escaped detection; but certainly could be found if looked for. So far nothing can be considered as abso- lutely proved with reference to the interior solidity of the earth from precession and nutation; but now think of the solar semiannual and the lunar fortnightly nutations. The period of each of these is less than 800 days. Now the hydro- dynamical theory shows that, irrespectively of the thickness of the shell, the nuta- tion of the crust would be zero if the period of the nutational disturbance were 300 times the period of rotation (the ellipticity being aa) if the nutational period were any thing between this and a certain smaller critical value depending on the thickness of the crust, the nutation would be negative; if the period were equal to this second critical value, the nutation would be infinite; and if the period were still less, the nutation would be again positive. Further, the 183 days period of the solar nutation falls so little short of the critical 5CO days that the amount of the nutation is not sensibly influenced by the thickness of the crust, is negative and equal in absolute value to ss (being the reciprocal of el) times what the amount would be were the earth solid throughout. Now this amount, as calculated in the ‘ Nautical Almanac,’ makes 0'°55 and 0'"51 the semiaxes of the ellipse traced by the earth’s axis round its mean position; and if the true nutation placed the earth’s axis on the oa side of an ellipse, having 0-86 and O'-81 for _ its semiaxes, the discrepance could not possibly have escaped detection. But, lastly, think of the lunar fortnightly nutation. Its period is Pa of 300 days, and its amount, calculated in the ‘ Nautical Almanac’ on the thecry of complete solidity, is TRANSACTIONS OF THE SECTIONS. vi such that the greater semiaxis of the approximately circular ellipse described by the pole is 00325. Were the crust infinitely thin this nutation would be negative, but its amount nineteen times that corresponding to solidity. This would make the greater semiaxis of the approximately circular ellipse described by the pole amount to 19 0'"0885, which is 1"*7._ It would be negative and of some amount between 17 and infinity, if the thickness of the crust were any thing from zero to 120 kilo- metres, This conclusion is absolutely decisive against the geological hypothesis of a thin rigid shell full of liquid. But interesting in-a dynamical point of view as Hopkins’s problem is, it can- not afford a decisive argument against the earth’s interior liquidity. It assumes the crust to be perfectly stiff and unyielding in its figure. This, of course, it cannot be, because no material is infinitely rigid ; but, composed of rock and possibly of continuous metal in the great depths, may the crust not, as a whole, be stiff enough to practically fulfil the condition of unyieldingness? No, decidedly it could not: on the contrary, were it of continuous steel and 500 kilometres thick, it would yield very nearly as muchas if it were india-rubber to the deforming influences of centrifugal force and of the sun’s and moon’s attractions. Now although the full problem of precession and nutation, and, what is now necessarily included in it, tides, in a continuous revolving liquid spheroid, whether homogeneous or hetero- geneous, has not yet been coherently worked out, I think I see far enough towards « complete solution to say that precession and nutations will be practically the same in it as in a solid globe, and that the tides. will be practically the same as those of the equilibrium theory. From this it follows that precession and nuta- tions of the solid crust, with the practically perfect flexibility which it wouid have even though it were 100 kilometres thick and as stiff as steel, would be sensibly the same as if the whole earth from surface to centre were solid and perfectly stitt, Hence precession and nutations yield nothing to be said against such hypotheses as that of Darwin*, that the earth as a whole takes approximately the figure due to gravity and centrifugal force, because of the fluidity of the interior and the flexi- bility of the crust. But, alas for this “attractive sensational idea that a molten interior to the globe underlies a superficial crust, its surface agitated by tidal waves, and flowing freely towards any issue that may here and there be opened for its outward escape” (as Poulett Scrope called it)! the solid crust would yield so freely to the deforming influence of sun and moon that it would simply carry the waters of the ocean up and down with it, and there would be no sensible tidal rise and fall of water relatively to land. The state of the case is shortly this:—The hypothesis of a perfectly rigid crust containing liquid violates physics by assuming preternaturally rigid matter, and violates dynamical astronomy in the solar semiannual and lunar fortnightly nuta- tions ; but tidal theory has nothing to say against it. On the other hand, the tides decide against any crust flexible enough to perform the nutations correctly with a liquid interior, or as flexible as the crust must be unless of preternaturally rigid matter. But now thrice to slay the slain: suppose the earth this moment to be a thin crust of rock or metal resting on liquid matter ; its equilibrium would be unstable ! And what of the upheavals and subsidences ? They would be strikingly analogous to those ofa ship which has been rammed—one portion of crust up and another down, and then all down. I may say, with almost perfect certainty, that whatever may be the relative densities of rock, solid and melted, at or about the temperature of liquefaction, it is, I think, quite certain that cold solid rock is denser than hot melted rock; and no possible degree of rigidity in the crust could prevent it from breaking in pieces and sinking wholly below the liquid lava. Something like this may have gone on, and probably did go on, for thousands of years after solidifica- tion commenced—surface-portions of the melted material losing heat, freezing, sinking immediately, or growing to thicknesses of a few metres, when the surface would be cool and the whole solid dense enough to sink. ‘This process must go * «Observations on the Parallel Roads of Glen Roy and other parts of Lochaber in ‘Scotland, with an attempt to prove that they are of marine origin,” Transactions of the Royal Society for Feb. 1839, p. 81. 8 REPORT—1876. on until the sunk portions of crust build up from the bottom a sufficiently close- ribbed skeleton or frame to allow fresh incrustations to remain, bridging across the now small areas of lava pools or lakes. “Tn the honeycombed solid and liquid mass thus formed there must be a con- tinual tendency for the liquid, in consequence of its less specitic gravity, to work its way up; whether by masses of solid falling from the roofs of vesicles or tunnels and causing earthquake-shocks, or by the roof breaking quite through when very thin, so as to cause two such hollows to unite or the liquid of any of them to flow out freely over the outer surface of the earth, or by gradual subsidence of the solid owing to the thermodynamic melting which portions of it under intense stress must experience, according to my brother’s theory. The results which must follow from this tendency seem sufficiently great and various to account for all that we learn from geological evidence of earthquakes, of upheavals and subsidences of solid, and of eruptions of melted rock.”* Leaving altogether now the hypothesis of a hollow shell filled with liquid, we must still face the question, how much does the earth, solid throughout, except small cavities or vesicles filled with liquid, yield to the deforming (or tide-gene- rating) influences of sun and moon? This question can only be answered by obser- vation. A single infinitely. accurate spirit-level or plummet far enough away from the sea to be not sensibly affected by the attraction of the rising and falling water would enable us to find the answer. Observe by level or plummet the changes of direction of apparent gravity relatively to an object rigidly connected with the earth, and compare these changes with what they would be were the earth perfectly rigid, according to the known masses and distances of sun and moon. The dis- crepance, if any is found, would show distortion of the earth, and would afford data for determining the dimensions of the elliptic spheroid into which a non-rotating globular mass of the same dimensions and elasticity as the earth would be distorted by centrifugal force if set in rotation, or by tide-generating influences of sun or moon. The effect on the plumb-line of the lunar tide-generating influence is to deflect it towards or from the point of the horizon nearest to the moon, according as the moon is above or below the horizon. The effect is zero when the moon is on the horizon or overhead, and is greatest in either direction when the moon is 45° above or below the horizon. When this greatest value is reached, the plummet is drawn from its mean position through a space equal to iZanam of the length of the thread. No ordinary plummet or spirit-level could give any perceptible indication whatever of this effect; and to measure its amount it would be necessary to be able 1 p : : to observe angles as small as j55500,900 Of the radian, or about ;3;". Siemens’s beautiful hydrostatical multiplying level may probably supply the means for doing this, Otherwise at present no apparatus exists within small compass by which it could be done. A submerged water-pipe of considerable length, say 12 kilometres, with its two ends turned up and open, might answer. Suppose, for example, the tube to lie north and south, and its two ends to open into two small cisterns, one of them, the southern for example, of half a decimetre diameter (to escape disturb- ance from capillary attraction), and the other of two or three decimetres diameter (so as to throw nearly the whole rise and fall into the smaller cistern). or sim- plicity, suppose the time of observation to be when the moon’s declination is zero. The water in the smaller or southern cistern will rise from its lowest position to its highest position while the moon is rising to maximum altitude, and fall again after the moon crosses the meridian till she sets; and it will rise and fall again through the same range from moonset to moonrise. Ifthe earth were perfectly rigid, and if the locality is in latitude 45°, the rise and fall would be half a milli- metre on each side of the mean level, or a little short of half a millimetre if the place is within 10° north or south of latitude 45°. If the air were so absolutely quiescent during the observations as to give no varying differential pressure on the two water-surfaces to the amount of ;4, millimetre of water or 5 ;4, of mer- cury, the observation would be satisfactorily practicable, as it would not be difficult * “Secular Cooling of the Earth,” Transactions of the Royal Society of Edinburgh, 1862 (W. Thomson), and Thomson and Tait’s ‘ Natural Philosophy,’ §§ (ee), (ff). TRANSACTIONS OF THE SECTIONS. 9 by aid of a microscope to observe the rise and fall of the water in the smaller cistern to 42, of a millimetre; but no such quiescence of the atmosphere could be expected atany time; and it is probable that the variations of the water-level due to difference of the barometric pressure at the two ends would, in all ordinary weather, quite overpower the small effect of the lunar tide-generating motive. If, however, the two cisterns, instead of being open to the atmosphere, were connected air-tightly by a return-pipe with no water in it, it is probable that the observation might be successfully made: but Siemens’s level or some other apparatus on a similarly small scale would probably be preferable to any elaborate method of obtaining the result by aid of very long pipes laid in the ground; and I have only called your attention to such an ideal method as leading up to the natural phenomenon of tides. Tides in an open canal or lake of 12 kilometres length would be of just the amount which we have estimated for the cisterns connected by submerged pipe: but would be enormously more disturbed by wind and variations of atmospheric pressure. A canal or lake of 240 kilometres length in a proper direction and in a suitable locality would give but 10 millimetres rise and fall at each end, an effect which might probably be analyzed out of the much greater disturbance produced by wind and differences of barometric pressure; but no open liquid level short of the ingens equor, the ocean, will probably be found so well adapted as it for measuring the absolute value of the disturbance produced on terrestrial gravity by the lunar and solar tide-generating motive. But observations of the diurnal and semidiurnal tides in the ocean do not (as they would on smaller and quicker levels) suffice for this purpose, because their amounts differ enor- mously from the equilibrium-values on account of the smallness of their periods in comparison with the periods of any of the grave enough modes of free vibration of the ocean as a whole. On the other hand, the lunar fort- nightly declinational and the lunar monthly elliptic and the solar semiannual and annual elliptic tides have their periods so long that their amounts must certainly be very approximately equal to the equilibrium-values. But there are large annual and semiannual changes of sea-level, probably both differential (on account of wind and differences of barometric pressure and differences of temperature of the water) and absolute, depending on rainfall and the melting away of snow and return evaporation, which altogether swamp the small semi- annual and annual tides due to the sun’s attraction. Happily, however, for our object there is no meteorological or other disturbing cause which produces periodic changes of sea-level in either the fortnightly declinational or the monthly elliptic period ; and the lunar gravitational tides in these periods are therefore to be care- fully investigated in order that we may obtain the answer to the interesting ques- tion, how much does the earth as an elastic spheroid yield to the tide-generating influence of sun or moon? Hitherto in the British-Association Committee’s reductions of Tidal Observations we have not succeeded in obtaining any trust- worthy indications of either of these tides. The St.-George’s pier landing-stage pontoon, unhappily chosen for the Liverpool tide-gauge, cannot be trusted for such a delicate investigation: the available funds for calculation were expended before the long-period tides for Hilbre Island could be attacked, and three years of Kur- rachee gave our only approach to a result. Comparisons of this with an indication of a result of calculations on West Hartlepool tides, conducted with the assist- ance of a grant from the Royal Society, seem to show possibly no sensible yield- ing, or perhaps more probably some degree of yielding, of the earth’s figure. The absence from all the results of any indication of a 18°6 yearly tide (according to the same law as the other long-period tides) is not easily explained without assuming or admitting a considerable degree of yielding. Closely connected with the question of the earth’s rigidity, and of as great scien- tific interest and of even greater practical moment, is the question, How nearly accurate is the earth as a timekeeper? and another of, at all events, equal scientific interest, How about the permanence of the earth’s axis of rotation ? Peters and Maxwell, about 35 and 25 years ago, separately raised the question, How much does the earth’s axis of rotation deviate from being a principal *axis of inertia? and pointed out that an answer to this question is to be obtained by looking for a yariation in latitude of any or every place on the earth’s surface in a 1876, 2 10 REPORT—1876. period of 306 days. The model before you illustrates the travelling round of the instantaneous axis relatively to the earth in an approximately circular cone whose axis is the principal axis of inertia, and relatively to space in a cone round a fixed axis. In the model the former of these cones, fixed relatively to the earth, rolls internally on the latter, supposed to be fixed in space. Peters gave a minute investiga- tion of observations at Pulkovain the years 1841-42, which seem to indicate at that time a deviation amounting to about 3," of the axis of rotation from the principal axis. Maxwell, from Greenwich observations of the years 1851-54, found seeming indications of a very slight deviation, something less than half a second, but differ- ing altogether in phase from that which the deviation indicated by Peters, if real and permanent, would have produced at Maxwell’s later time. On my begging’ Professor Newcomb to take up the subject, he kindly did so at once, and undertook to analyze a series of observations suitable for the purpose which had been made in the United-States Naval Observatory, Washingtou. A few weeks later I received from him a letter referring me to a paper by Dr. Nysen, of Pulkova Observatory, in which a similar negative conclusion as to constancy of magnitude or direction in the deviation sought for is arrived at from several series of the Pulkova obser- vations between the years 1842 and 1872, and containing the following statement of his conclusions : — “The investigation of the ten-month period of latitude from the Washington prime vertical observations from 1862 to 1867 is completed, indicating a coefficient too small to be measured with certainty. ‘The declinations with this instrument are subject to an annual period which made it necessary to discuss those of each month separately. As the series extended through a full five years, each month thus fell on five nearly equidistant points of the period. If « and y represent the coordinates of the axis of instantaneous rotation on June 30, 1864, then the obser- vations of the separate months give the following values of w and y:— ; vie Weight. y- Weight. January i... —0:35 10 +032 February ...... —0:03 14 +009 Mareh:::......5.: +017 10 +0°16 April i.cscciesces 40-44 5 40:05 Maretsreai..ais: +0:08 16 +002 TUNG, -acgeassnisk —001 14 —0-01 Duly. seenacstt oa —0:05 1 0:00 pRUPUBE «05 <0 e840 —0°-24 14 +0°29 September ...... +0°18 14 +0°21 October ...;..... +0:13 14 —0-01 November ...... +0:08 17 —0-20 December ...... —0:08 16 —0:08 Mean...... 0:01-0:03 +0°05-+0:03 ** Accepting these results as real, they would indicate a radius of rotation of the instantaneous axis amounting, at the earth’s surface, to 5 feet and a longitude of the point in which this axis intersects the earth’s surface near the North Pole, such that on July 11, 1864, it was 180° from Washington, or 103° east of Greenwich. ‘The excess of the coefficient over its probable error is so slight that this result cannot be accepted as any thing more than a consequence of the unavoidable errors of observation.” From the discordant character of these results we must not, however, infer that the deviations indicated by Peters, Maxwell, and Newcomb are unreal. On the contrary, any that fall within the limits of probable error of the observations ought properly to be regarded as real. There is, in fact, a vera causa in the temporary changes of sea-level due to meteorological causes, chiefly winds, and to meltings of ice in the polar regions and return evaporations, which seems amply sufficient to- account for irregular deviations of from 3” to 3," of the earth’s instantaneous axis from the axis of maximum inertia, or, as I ought rather to say, of the axis of maximum inertia from the instantaneous axis, As for geological upheavals and subsidences, if on a very large scale of area, 2: TRANSACTIONS OF THE SECTIONS. Bi they must produce, on the period and axis of the earth’s rotation, effects comparable with those produced by changes of sea-level equal to them in vertical amount. For simplicity, calculating as if the earth were of equal density throughout, I find that an upheaval of all the earth’s surface in north latitude and east longitude and south latitude and west longitude with equal depression in the other two quarters, amounting at greatest to ten centimetres, and graduating regularly from the points of maximum elevation to the points of maximum depression in the middles of the four quarters, would shift the earth’s axis of maximum moment of inertia through 1" on the north side towards the meridian of 90° W. longitude, and on the south side towards the meridian of 90° E. longitude. If such a change were to take lace suddenly, the earth’s instantaneous axis would experience a sudden shifting of ut gt5” (which we may neglect), and then, relatively to the earth, would com- mence travelling, in a period of 306 days, round the fresh axis of maximum moment of inertia. The sea would be set into vibration, one ocean up and another down through a few centimetres, like water in a bath set aswing. ‘The period of these vibrations would be from 12 to 24 hours, or at most a day or two; their subsidence would probably be so rapid that after at most a few months they would become insensible. Then a regular 306-days period tide of 11 centimetres from lowest to highest would be to be observed, with gradually diminishing amount from century to century, as through the dissipation of energy produced by this tide the instantaneous axis of the earth is gradually brought into coincidence with the fresh axis of maximum moment of inertia. If we multiply these figures by 3600, we find what would be the result of a similar sudden upheaval and sub- sidence of the earth to the extent of 360 metres above and below previous levels. It is not impossible that in the very early ages of geological history such an action as this, and the consequent 400-metres tide producing a succession of deluges eyery 306 days for many years, may have taken place; but it seems more pro- bable that even in the most ancient times of geological history the great world- wide changes, such as the upheavals of the continents and subsidences of the ocean- beds from the general level of their supposed molten origin, took place gradually through the thermodynamic melting of solids and the squeezing out of liquid lava from the interior, to which I have already referred. A slow distortion of the earth as a whole would never produce any great angular separation between the instantaneous axis and axis of maximum moment of inertia for the time being. Considering, then, the great facts of the Himalayas and Andes, and Africa and the depths of the Atlantic, and America and the depths of the Pacific, and Australia, and considering further the ellipticity of the equatorial section of the sea-level esti- mated by Capt. Clarke at about =} of the mean ellipticity of meridional sections of the sea-level, we need no brush from the comet’s tail (a wholly chimerical cause which can never have been put forward seriously except in ignorance of elementary dynamical principles) to account for a change in the earth’s axis ; we need no violent convulsion producing a sudden distortion on a great scale, with change of the axis of maximum moment of inertia followed by gigantic deluges; and we may not merely admit, but assert as highly probable, that the axis of maximum inertia and axis of rotation, always very near one another, may have been in ancient times very far from their present geographical position, and may have gradually shifted through 10, 20, 30, 40, or more degrees without at any time any perceptible sudden disturbance of either land or water. Lastly, as to variations in the earth’s rotational period. You all no doubt know how, in 1853, Adams discovered a correction to be needed in the theoretical calcu- lation with which Laplace followed up his brilliant discovery of the dynamical explanation of an apparent acceleration of the moon’s mean motion shown by yecords of ancient eclipses, and how he found that when his correction was applied the dynamical theory of the moon’s motion accounted for only about half of the observed apparent acceleration, and how Delaunay in 1866 verified Adams’s result and suggested that the explanation may be a retardation of the earth’s rota- tion by tidal friction, The conclusion is that, since the 19th of March, 721 B.c., a day on which an eclipse of the moon was seen in Babylon, commencing “when one a 1 hour after her rising was fully passed,” the earth has lost rather more than = Djg09 O*% 12 REPORT—1876, of her rotational velocity, or, as a timekeeper, is going slower by 114 seconds per aunum now than then. According to this rate of retardation, if uniform, the earth at the end of a century would, as a timekeeper, be found 22 seconds behind a perfect clock, rated and set to agree with her at the beginning of the century. Newcomb’s subsequent investigations in the lunar theory have on the whole tended to confirm this result; but they have also brought to light some remarkable ap- parent irregularities in the moon’s motion, which, if real, refuse to be accounted for by the gravitational theory without the influence of some unseen body or bodies es near enough to the moon to influence her mean motion. This hypothesis Newcomb considers not so probable as that the apparent irregularities of the moon are not real, and are to be accounted for by irregularities in the earth’s rotational velocity. If this is the true explanation, it seems that the earth was going slow from 1850 to 1862, so much as to have got behind by seven seconds in these twelve years, and then to have begun going faster again so as to gain eight seconds from 1862 to 1872. So great an irregularity as this would require somewhat greater changes of sea-level, but not many times greater than the British Association Committee’s reductions of tidal observations for several places in different parts of the world allow us to admit to have possibly taken place. The assumption of a fluid interior, which Newcomb suggests, and the flow of a large mass of the fluid “from equatorial regions to a position nearer the axis,” is not, from what I have said to you, admissible as a probable explanation of the remarkable acceleration of rotational velocity which seems to have taken place about 1862 ; but happily it is not necessary. A settlement of 14 centimetres in the equatorial regions, with cor- responding rise of 28 centimetres at the poles (which is so slight as to be absolutely undiscoverable in astronomical observatories, and which would involve no change of sea-level absolutely disproved by reductions of tidal observations hitherto made), would suffice. Such settlements must occur from time to time; and a settlement of the amount suggested might result from the diminution of centrifugal force due to 150 or 200 centuries’ tidal retardation of the earth’s rotational speed. MarHeMarics. Sur les Mowements apériodiques des Systemes de Points Matériels. By M. Vatnyrino Crerrvtt. A short communication referring to a system of points subject to their mutual action and to that of fixed exterior points. Sur les Systémes de Spheres et les Systemes de Droites. By Professor Lurct Cremona. Cette communication avait pour objet d’exposer une méthode pour transformer les congruences (systémes doublement infinis) de droites, contenues dans un com- plexe linéaire donné, de maniére qu’a chaque droite de la congruence corresponde un point dune surface, et vice-versa. La méthode résulte de la combinaison des transformations de l’espace & trois dimensions, exposées par J’auteur dans les ‘Annali di Matematica’ (série 2°, tome 5°), avec la transformation, donnée par MM. Noether et Lie, d’un complexe linéaire en l’espace ordinaire (point-espace). Suivant cette transformation, les plans de l’espace correspondent aux congruences linéaires du complexe donné qui contiennent une droite fixe; et aux autres congru- ences linéaires du méme complexe correspondent les sphéres de espace ordinaire. La méthode exposée dans la communication donne toutes les transformations d’un complexe linéaire en l’espace ordinaire, telles qu’aux congruences linéaires con- tenant une droite fixe correspondent des surfaces d'un ordre donné. En particulier, on obtient toutes les congruences (non-linéaires, contenues dans le complexe donné) qui sont susceptibles d’étre représentées sur un plan, de maniére que chaque droite de la congruence ait pour image un point déterminé du plan et que, vice-versa, TRANSACTIONS OF THE SECTIONS. 13 chaque point du plan corresponde a’ une droite unique de la congruence. i l'on transforme le plan par les polaires réciproques de Poncelet, les images des droites de la congruence seront les droites du plan représentatif. On Graphical Interpolation and Integration. By Grores H. Darwin, M.A., Fellow of Trin. Coll., Cambridge. Suppose a number of points A, B, C, &e. are given on equidistant ordinates of a curve, and that it is desired to draw a curve through them. This may be best done by interpolating intermediate points. Let a, b,c, &c. bs ordinates halfway between A and B, Band C,&c. Join AB, BC, &c. along the whole curve, and let the ordinates a, 6, c, &e. intersect AB, BO, CD, &e. in f, g, h, &e. Join AC, BD, CH, &e., and so on along the whole curve, and let the ordinates B, C, D, &c. inter- sect AC, BD, CE, &c. in F, G, H, &e. Then the rule for interpolating on the ordinates a, b,c, &c. is:—produce af to J, and make f/ = } BF; produce bg to m, and make gm = 4 CG, and so on. In carrying this out practically, several of the above lines need not actually be drawn. This rule may be proved from the properties of the circle of curvature, which passes through three consecutive points, such as A, B,C. It gives results correct as far as second differences. A slightly different result will be obtained by working along the curve in the opposite direction : to obtain a better result work both ways along the curve, and choose the points which lie halfway between the discrepant readings. The result so given is correct as far as third differences. In determining the approximate value of a definite integral it is cften convenient to find a geometrical construction for giving a line proportional to the function to be integrated, and then to determine half a dozen values of the function. But the question then arises as to how these terms are to be combined, so as to give the required integral—whether by the rules given by the calculus of finite differences, or by the simpler rule of taking the mean of the extremes and adding it together with all the rest, and multiplying by the common difference. Each ordinate or term is affected by an error, and it may be that the theoretically best rule may give a higher probable error to the result than the more imperfect rule. If, for example, we have seven ordinates, each subject to a probable error ec, Weddle’s rule (see Boole’s Cale. Fin. Diff.) would give a result subject to a probable error 2°846 he, whilst the worse rule only gives a probable error 2°345 he, where h is the common difference. It must therefore remain indeterminate whether more is gained by a diminished probable error or by a better rule of quadratures. The question could only be determined by some knowledge of the amount of probable error of each ordinate, and of the abruptness of the curvature of the curve*. On certain Determinants. By J. W. L. Guaisuer, M/.A., FBS, The author gave the following results :— I. If P, denote the number of partitions of into the elements 1, 2, 3,4, ...., repetitions not excluded, then P= foley ——ild Mig umral wes) oS. +1, +1, —1, ©; os bs ee +1, +1, —1, Ci herd a +1, +1, —l, -1, ry ors +1, +1, —l, as 2 pte ; a -l, _ where the first column is * Tho paper is printed 7 extenso in the ‘ Messenger of Mathematics,’ vol. vi. (January - 1877). 14 REPORT —1876. +1,+1,0,0, — 1,0, —1,0, 0,0, 0, + 1,0, 0, + 1, 0, 0, 0, 0, 0, 0, — 1,0, 0, 0, 9,0, 6,'0,.0)'0; 0700, du, 84 viz. between two unities of the same sign the numbers of zeros follow the law 0,1, 2,3,4...., while the numbers of zeros between two unities of opposite sign follow the law 2, 4, 6,8 ....; the second column is the same as the first column, but lowered one line, and with —1 as the top constituent; the third column is the same as the second line, but lowered one line, and with zero as the top constituent ; the fourth column is the same as the third column, but lowered one line, and with zero as the top constituent; and so on. For example :— P,=|+1, —1, e |=3 +1, tals = ©, +1, 41 which is right, since 3=14+1+1=1+42. II. If (x) be the sum of the divisors of x, then V(n)= +1, -1, ase) ee) ets +2, +1, -1, Sus 2» » vee |(” rows) where all the constituents remain as before, except those in the first column, in which the rth constituent appears multiplied by 7. Thus the non-zero constituents in the first column are the pentagonal numbers, of the form 3n(3n+1). For example :— W(3)=|+1, —-1, + |=4 ds abs veod Ce +1, +1 which is right, since (3) =1+5=4. Ill. Consider the determinant Vol 2.) Bbe 45501 B> eee 1 Gere] rome) 1, Ry Dr ri8ig 3, e- a its 2; ay is Ps os Pees 8, 2.5 Ps eran Rpts ic, a Ps aia Lae he ee | wherein the top line contains the natural numbers beginning with 2 and ending with n; the second line is obtained by dividing the constituents of the top line by 2, and entering the quotient or zero according as each constituent is or is not diyi- sible by 2; the third line is obtained by dividing the constituents of the top line by 3, and entering the quotient or zero according as each constituent is or is not divisible by 3; and so on. Then V=0Oif x is divisible by any square factor, and V=(—)"*n if nis asimple product of prime factors; viz. eBy.... € where a, 8, y....é are different primes, and N denotes the number of prime divisors of x, unity included. For example :— =(—)°*%6 ee@oe Rb eo e@ero CD re e WWD which is easily verified, — or TRANSACTIONS OF THE SECTIONS, On a Series Summation leading to an. Expression for the Theta Function as a Definite Integral. By J. W. L. Guatsure, M.A., PRS. By means of the formula giving the resolution of 1-+-x” into its linear factors, and if the equation eae 1) earl (ae it can be shown that a” av dag See Al eile Alida ee few {1+ | cae { taf 1+ (a+26)2 eis Ey ° Be P,P, ...+ Pr-s if m be even, and cosec 7a)" (co sh ae —cos om \P, P,P,....P,-2ifmbe uneven, where 2Qn 2Qn Ine. On x { cost ‘es sin a3 cos Fate cos =) } : ; 2. a ae (“Ei sin 5) — cos = (a —2 cos") , 2n and cosh .v, sinh a are written as usual for the hyperbolic cosine and sine of 2, viz. cosh r=3(e*+e—*), sinh z=3(e*—e-*). Taking the logarithm and differentiating, we have 1 i 1 1 2 2n—1 ee . t a +a" a 2+ (a— BE x" +(a+b)” + an (q—2Qb)™ + &e. } ; 1 + (ad aie Qi FQ TG, one. +Q., } if n be even, ley wa \ = +Q,+Q5-+-- +Qn—2 > if m be uneyen; ve Qe. =) z( Feces (= sin 55 +cos 7 7 sin = plate cos 5) Qnx . 118 20 rr cosh ae sin ony e08 F(a+zc0s =) Using the integral, i) 2n—1 nn n e sin (¢ & —," anf seas 0 r 16 REPORT—1876, we haye ea" 4 eeu b)" 4 e—e"(atb)" 4 p—C"(a 28)" 4 p= OM a20)" 4 &e. = ‘{ { OOF Ooi psin(e'e" jar, if n be even, bo of ., Qe 9 sinh Fi | aes =e tre ra FU +OQ5.- ++ F Quo - sin(c"a") da, if n he cosh ee | uneyen. The exponents on the left-hand side are always to be numerically negative, viz. they should be written — / {c?"a?"}, Vv {e"(a—b)™*}, &e. The quantity ¢ is redun- dant, and may be put equal to unity without loss of generality. Putting n=2 and c=1, we find that sity 20° 2. Cye\ en ee e-a?-+f —(a—b)? 4. e~ (at bY 4. &e, =v? ( {f (= >) +f ie =S) }sin ada, where : _ sinh pf 2+s8in (pr/2+2¢) I (Ps 1) = cosh px/2—cos (py 9-£99)" Now 2 a. Ire 7? + e—(r~a)? + e—(«+a)? + &a= vn | 1+ Qe *" cos eas a 4n? a Sr eer: a +2e cose" 4. &e, |; a whence, the notation being that of the ‘Fundamenta N ova,’ it can be shown that orev Ck): a {162+ tm) +4 (— 2-40) ) sin ae, nd therefore o(a)=a/ (2) : ( \f (at, u)+ f (cet, —w) }sin dt, Jo a aK 7 - a= xk’ w= aK (@+K). where Also it can be shown that @(«) Bay") 3 {. { plat, u)+p(at, —w) \ cos tde, _ sinh p¥2—sin (py¥2+42y) PD cosh py/2—cos (p24) where On Parallel Motion. By W. Haypen. Tm this paper the author noticed several cases of approximate three-bar parallel motion, founded upon certain numerical coincidences, __— ——S TRANSACTIONS OF THE SECTIONS, 17 On Plane Cubies of the Third Class with a Double and a Single Foeus. By Henry M. Jerrery, M.A. 1. The classification of class-cubics is simpler than of plane order-cubics, because ‘there are three real foci in each of the former, whereas two of the asymptotes of order-cubics may be imaginary. The three groups, arranged by the coincidence of the foci, have been stated in the Transactions for 1875, and the third group of spherical curves there sketched. This group (kp*=g) has been also fully considered in the ‘ Quarterly Journal of Mathematics’ for 1876, both for plane aad spherical class-cubics, with illustrative diagrams. These two memoirs contain complete classification of circular cubics by interpreting Boothian as Cartesian coordinates. 2. In the classification of the second group (xp-g=r) the two foci will be con- sidered fixed, while the satellite-point varies. There is a certain quartic curve, the locus of the satellite-point, when there is a point of inflexion in the curve; if the satellite-point is within this curve, there will be three critic lines or bitangents ; if it be on the curve, there will be one bitangent and two others coinciding in a sta- tionary tangent; if it fall beyond the bounding curve, only one bitangent is possible. The critic lines or bitangents are the common tangents of three parabola, whose foci are severally the satellite-point and the two foci of the cubic. When these parabole are drawn, the bitangents are obtained oraphically. The several cases of cubics of this group will be next considered, according to the position of the satellite with reference to the bounding curve while all three points are finite; and subsequently, when the satellite-point and the foci are, one or more, at infinity; also when the three points are collinear. 3, The group may be thus represented :— kp’g+4A°7=0, where 4A°=apP-+gQ+crR; p, g,7 are the current line coordinates, and P=ap— bq cos C—er cos B: Q, R have like values for points at infinity, as the quadrantal poles of the sides of ABC. There are usually three critic lines, whose equations are obtained by partial differentiation :— apP =4A?(1) : bgQ=2A°(2) : rR=—2A°(8). Since the condition p=g=r satisfies all these equations, the critic lines must touch three parabole, whose foci are the vertices and whose axes are the perpen- diculars drawn on the sides of the triangle of reference, and, latera recta, are four times, twice, and six times its corresponding altitudes. There are three of these critic lines, one of which is always real. 4, The Cartesian equation to the bounding curve (§ 2), or locus of the satellite- point, when there are stationary points in this group of class-cubics, is Q7yo+9y'(24+4e+52°)+y?(1+2)(—1—102+92*)—2°(1492)(1+2)?=0, or {27y'+18y%(a+1)?— (9e- +1) (e$1)} (y2-+2") =0. The double focus is the origin, and the focal distance on the 2 axis is taken as unity ; a pair of asymptotes is inclined to the diameter at angles +30°. ‘The envelop of the stationary tangent is a hyperbola, and of the single (one- with-twofold) bitangent is a cubic of division V., whose double focus is at in- - finity. 5. Classification of the figures of class-cubics with double foci*. ua eran the satellite-point lies beyond the bounding quartic, there is one bitan- gent only. The triangle of reference formed by the foci and the satellite-point is taken to be equilateral. _* The diagrams illustrating the critical and the companion-curyes, according to these pe capital divisions, were exhibited at the Glasgow Meeting, and are ready for publi- cation. 18 REPORT—1876. Let the cubic be thus denoted :— pq=kr. The critical value (k=5:1458) determines the bitangential cubic. The cubic is bipartite or unipartite, according as x><6'1458 ; equiharmonic if «= 1°67 or —'17; harmonie if k= —‘15. There may be two real asymptotes, since there is one bitangent in this division. II. When the satellite-point is on the bounding sextic. In this case there are two- critical values of the parameter, corresponding to the bitangential and inflexional cubics, viz. 11:09 and ‘08. The curve is bipartite if «k>11-09. III. When the satellite is inside the quartic, and is (1) not collinear, and (2) is collinear with the foci. (1) There are three bitangents when c=47, ‘07,06. For higher values of x, the curve is bipartite; between 47 and ‘07, unipartite; then bipartite and below the bitangential curve unipartite. There may be four asymptotes. (2) Let the cubic be thus denoted :— d(1-++b8)-+(1+c8)(2+n")=0. There are two bitangents with real and imaginary contact, as is thus shown :— 4+} (27¢?—18be—b?) + 4n*b*e=0. For the inflexional genus, the discriminant gives the condition 64b°c = (27c° —18be —b?)’. This may he resolyed into two factors :— (b—c) (b—9e)?, The first factor resolyes the cubic into a point and a circle ; the second factor indi- cates the cissoid : (S+bE)? +b°(9+b€)n? =0. The satellite-point in this case is the apse in the quartic bounding curve. IV. If the satellite-point be at infinity (1) not collinear, (2) collinear, with the two foci. (1) There are two bitangential or a single inflexional, or no bitangential form, according as the satellite lies within, upon, or beyond the quartic curve. One asymptote connects the double focus with the satellite; the other three concur in the point (= 43); the polar conic of the line at infinity degenerates into these oints. y (2) There may be two asymptotes, which unite in a bitangent, for a special value of the parameter. Y. If the double focus is at infinity, (1) not collinear, (2) collinear with the single focus and satellite-point. The cubic has in all cases a bitangent; and for a particular value of the para- meter two bitangents coincide in a stationary tangent at a point of inflexion. The inflexional cubic in (2) is the semicubical parabola. VI. If the single focus is at infinity (1) not collinear, (2) collinear with the double focus and satellite. There are two bitangential forms, but no inflexional case. The reciprocals in (2) are Newton’s defective hyperbole, with diameters and double foci. VII. If the single focus and satellite-point are both at infinity. The curve is central and parabolic, with a cusp at infinity, but cannot have a bitangent. Its single asymptote connects the double focus with the satellite. All cubics are equiharmonic of the form NE+(W 3E+n)(L+7°). {t is thus denoted in Boothian coordinates :— AE+ (aG+ by) (E +77) =0, The reciprocal is Newton's central species (38). TRANSACTIONS OF THE SECTIONS. 19 VIII. If the double focus and satellite-point are both at infinity. There is an inflexional form in all cases, as appears from the equation to the system :— AEH (aE+bn (Er) =9. The reciprocal is a cusped cubic. IX. If the double and single focus are both at infinity. The line at infinity is an acu-bitangent in all cases, as is shown by the equation to the system :— AE*(aE+by) + (E+7°) =0. 6. To find the asymptotes of this group of class-cubics. Since the polar-point of an asymptote (p, q, 7) lies on it, and also is at an infinite distance, the coordinates of an asymptote must satisfy two equations :— PA pepe aaer— OIA ee. 6. 8 A) and that to the polar conic of the line at infinity dp ap db _y {Atm ¢ Et wertp) tao, one of whose foci, as we should anticipate, is the double focus. The four asymptotes touch a conic, whose foci are p=0, 2g+-p=0. Hence also Mee bint a) shy he, 8 aw, ely tba) ee Gee) The elimination of » from (2) and (3) is a quartic equation. Hence there cannot be more than four asymptotes. Its discriminant is a factor of the discriminant of the ternary cubic (1). Two imaginary asymptotes always connect the double focus with the circular points at infinity. If the satellite (which is always on the curve) be at infinity, its connector with the double focus is an asymptote. The extremities of two asymptotes may coincide in a bitangent. : 7. The centre or polar point of the line at infinity is on AB, the connector of the foci, at the distance } AB from A, the double focus. AC touches the cubic in C; BC touches it where it meets the line (8B—«cy=0). On Spherical Class-cubics with Double Foci and Double Cyclic Ares. By Henry M. Jerrery, M.A. 1, This group may be denoted by line coordinates, as i plano :— kp>g +(6V)?r=0, (6V)?=3(a°p?—2begr cos A), where and the coordinates p, g, * denote the sines of the perpendiculars from the vertices ABC on a tangent are; and generally the symbols may denote the sines of arcs. There are four critic values of the parameter and four bitangential values. By partial differentiation, for a critic value, Qkpq+2raP =0: Kp?+27dQ=0: (GV)?+2rcR =0, where P =ap—bq cos C —cr cos B; and similar expressions denote Q, R; the line- coordinates of a tangent are referred to the polar triangle as one of reference. These conditions for a bitangent may be thus written :— apP =(6V)? : 2bgQ= (GV)? : 2erR=—(6V)*. These equations denote three spherical ellipses, whose foci are in the several cases the points of reference A, B, ©, and the corresponding points of reference of the polar triangle of ABC. 20 report—1876. 2, There is a sextic bounding curve, the locus of the satellite-point, when there is a point of inflexion; this curve is bipartite with an oval. If the satellite is within the oval, four critical values of the parameter yield bitangential forms of the cubic; if the satellite is on the oval, one intlexional and two bitangential eubics ; if the satellite is outside the oval, two bitangential cubics. Its equation, in Gtider- mann’s coordinates, is {(4B?-43)y° + (40) 0430) P= 27 V4 De +y) {ody 49°F If the two foci are a quadrant apart, b=, and the bounding sextic becomes 4y?41=3(e+y")* 8. All cubics with double foci have double cyclic ares. Let the line-equation to these cubics be written Ska bp*g+scrs(ap* —2berg cos A) =0. Its equivalent point-equation may be thus arranged :— (82+ 2By cos A + y?) { —12By°k? + 3x°(88?y7?—a°y? + 2782+ 18e2By cos A —20aBy?cos C-+56a8" cos B)+12«{ —6*y — aB* cos B-+-atcos A —a®y cos C —3af’y cos C+ (— cos B+2 cos A cos C)a*é + (cos A—2 cos B cos C) a?6* —(142 cos? C)a’By]} +12(6V)? (= *) ° { B?y?x? +2 (—B?y — 4s" cos B a +4a?B? cos A+3a7By +2a8*y cos C) + (a?+2a8 cos C+ 2")? ; But, if V denote the volume of the tetrahedron constituted by the centre of the sphere and the angular points of the triangle of reference, (GV)?=3(a’a? + 2beBy cos a) =(aatbB cose+cy cos b)?+b7c?(B?+28y cosA+y’). Hence if p=0 be a double focus, its quadrantal polar (aa+08 cos e—cy cos b=0) is a double cyclic are. (See §7.) The proposition seems to be susceptible of simple proof and of generalization. 4, If a spherical curve have a multiple cyclic arc, 1t has at least a double focus. Let the triangle of reference be trirectangular (which assumption does not aftect the generality of the proof), and let the quartic exhibit AB as a multiple cyclic are :— pret (a EY +2") Xn =0. The terms may be thus grouped :— (x Ty’) Xm+27(2" hr +Xm)- In this form the imaginary lines (7+yi=0) are seen to meet AB in two coincident . points I,J ; the tangents at these points are these ares CI, CJ: their point of con- currence is therefore a double focus. This proof seems applicable only to the case where the focus is the quadrantal pole of the cyclic erc, the points I, J being in this case the shadows of the circular points at infinity. The argument may be also thus stated. The two lines (w +yi=0) are common tangents to the curve, and to the imaginary sphere (a+y*+ ped =, ....3 and in regard to them he says :—“ So that we may be assured that the fraction : approaches nearer the truth than any other fraction whose denominator is less than 7; also the fraction 2 approaches nearer the truth than any other fraction whose denominator is less than 106; and so of others.” ‘ 34 ‘ ‘ The statement here made in reference to ; is easily seen to be incorrect by com- paring the difference of > from 7 with that of 2 ¢ oa or 5 , the former being, of course, ‘14159... , and the three latter *10840..., ‘05840..., ‘02507... ; and the incorrectness extends to what is said of the other convergents. The true solu- tion lies in the fact that not only is 5 +7 one of the required fractions, but so also Qe 28° REPORT—1876. are +i, 8+5, 8+5 where the denominator we begin with is the first integer greater than the half of 7: similarly, that before we come to 1 gai BL 347 415 we have ily il ST 74H na ST 749) 3 1 1 +7+i0 and soon. When an even partial denominator occurs, we take as the partial deno- minator to begin with, either its half or the first integer greater than its half, accor- ding as the partial denominator following is greater or less than that preceding, or, these being equal, according as the next following is less or greater than the next preceding, and so on. ai Another improvement, though verbal, is important, viz. in regard to the term convergent, the present definition of which seems arbitrary and unreasonable. With great convenience it may be defined a3 follows :—A convergent of a fractional number is a fraction which is a closer approximation to the given number than any other fraction with a smaller denominator; so that Lagrange’s problem is simply to Jind all the convergents of any fraction. On the Relation between two continued Fraction Expansions for Series. By Tuomas Mum, M.A., FLRS.E. On the Use of Legendre’s Seale for Calculating the First Elliptic Integral. By Professor F. W. Newman. Denoting the first elliptic integral by F(c,), and taking x such that 2:3 9 =F (e, ): F(e, 4); then, in Lagrange’s scale, from we deduce successively ,, ®,,@,.... by agiven law, with the aid of ¢,,¢,,¢,.... previously determined from ¢. Then v is the limit to which o,2-1'o,,2-*0,,2-°@,.... converge. If ¢ is mode- rately small, the convergence is rapid. But if c* is very near to 1, it may be ex- pedient to reverse the direction of the new amplitudes and moduli, viz. to calculate e backwards c’, ce’, c’”, so as to make e’", c", c', ¢, ¢,, Coy»... & Series continued by a single law; and similarly from calculate backwards o',0",o"’..... Then o’, o",o'’,..,, are proved to converge to a fixed limit o and F(e, o) : F(b, 3r)=Nap log tan (t7+30'):3a. The function Nap log tan (+ 7-+3 o') involves but a single element o’, and was calculated by Legendre. Gudermann has since published a far ampler table. In practice the limit is quickly reached: often it suffices to make o =o’, at worst wo =o". Thus for very large values of c? Lagrange’s scale prac- tically suffices, presuming that we have at hand tables of F(c, 37) and F(}, 37). But Legendre, who discovered a new scale after completing his principal caleu- lations, regarded his new scale as having much advantage in finding F(e, @) at once rapidly and accurately. In it 2 is the limit of @,3-10,,3-70,,3-%@, ...., and the convergence, generally excellent in Lagrange’s scale, is far more rapid in Legendre’s. In Lagrange’s scale the relation of , to w is tan (o,—o)=5 tan o. The relation in Legendre’s scale is to the eye as simple, viz. tan 3(@,—o)=A tan w; but in the constant A, = / (1—ce* sin °8), the value of 8 is determined by the equa- tion F(c, 8)=2F (ec, 47). A practical difficulty arose in the very considerable trouble needed to obtain A (or its logarithm) numerically when ¢ was given. Legendre showed how B was obtainable from ¢: the cubic equation arising can be solved by a mere extraction of the cube-root; but there are also two quadratics involving two extractions of the square-root, Then from 8 we have to calculate /(1—¢* sin °8) TRANSACTIONS OF THE SECTIONS, 29 and find its logarithm before we can proceed to deduce , from o. All these operations have to be repeated to find , from @;; nay, we must first find ¢, from e, and that is still more arduous. __ , But when we assume p, = Ine 2, as argument, all is greatly simplified. 72 The relation of ¢, cy, ¢,, ¢, .... in Lagrange’s scale corresponds with p, 2p, 2*p, 2°, ..., and in Legendre’s scale with p, 3p, 3’p, 3°p ...., which inyolve no trouble 1 calculating. No doubt we need tables (of single entry and easily compiled) to yield c, b when p is given, and p when c is given. Presuming these, we may treat « and F(c, ) as functions of p and w; after which the difficulties of the constant multi- plier A vanish, and Legendre’s scale becomes practical to us. Denote — log A, #7. e. — log /(1—ce’ sin *8), for the moment, by ®(p) (here the common log is intended) ; then, among the numerous series which express functions of the amplitude in terms of « and p, the author selects (with A for Napier’s log) 1l—eos2x , 1l—cos6r , 11— cos 10x sin2p 13 sin@p 15 «in 10p where sin p is written for 3(e?—e~?°). By hypothesis, F(e, 8)=3?1(c, 37); hence when o=f, z=47, and we get, writing cosec p for the reciprocal of sin p, }®(p) =M{cosec 2p +1 cosec 10p ++ cosec 14p+71; cosec 22p+&e.}, M being the mo- dulus of the common logarithms. Assuming that we have a table of #(p), then given p and w we have the equation log tan }(#,—o)= log tan # — ®(p) to finde, ; log tan 3(#,—,)=log tan w,—®(8p) to find w,; log tan }(#,—o,)=log tan o,—(37p) to find w,, and so on. The approximation is sufficient when ®(3"p) is negligible; and this result is obtained so rapidly, that in the extreme case of p=3, = 37a, is correct to ten decimals. To bring the method to a practical trial, the author has calculated to twelve decimals a skeleton table of &(p) for p=0'5, 0°6, 0:7, 0°8, 0-9, and from p=1 to p=14'3 at intervals of 0-1. ‘The table is given in the paper, and also exam- ples of the method. The process also by which the table was constructed, with +d = of tables of cosec p and e?, previously calculated by the author, is ex- plained. —ir. 7 d—e’ sin ?0)= + &e., General Theorems relating to Closed Curves. By Professor P. G. Tarr. The closed curves contemplated are supposed to have nothing higher than double points. By infinitesimal changes of position of the branches intersecting in it, a triple point is decomposed into three double points, a quadruple point into six, and generally an zple point into oe double points. (1) A closed curve cuts any infinite unknotted line in an even number of points [infinite here implies merely that both ends are outside the closed curve]. 6) The same is true if the line be knotted. (8) If any two closed curves cut one another, there is an even number of points of intersection, (4) In going continuously along a closed curve from a point of intersection to the same point again an even number of intersections is pessed. (5) Hence in going round such a closed curve we may go alternately above and below the branches as we meet them. (6) By (8) the same proposition is true of a complex arrangement of any number of separate closed curves super- posed in any manner. (7) In passing from the interior of any one cell to that of any other—in any system of superposed closed curves—the number of crossings is always even or always odd, whatever path we take. (8) Hence the cells may be coloured black and white in such a way that from white to white there is always an even number of crossitgs, and from white to black an odd number. Such closed curves therefore divide the plane as nodal lines do a vibrating plate. The above are the enunciations of the propositions proved in the paper, which, with the necessary figures &c., will be found printed iz evtenso in the ‘ Messenger of Mathematics,’ vol. vi., January 1877. 30 REPORT—1876, On a Theorem in the Mensuration of certain Solids. By Professor Jamms THomson. On Division-remainders in Arithmetic. By W.H. Wateny. The author referred to a series of papers of his on unitation recently published in the ‘ Philosophical Magazine,’ and to some remarks published in the Brit. Assoc. volume for 1870, If x divided by 6 leave remainder y, then the author calls y the unitate of « to the base 6, and writes Usz=y. The results of “unitation” may be conveniently applied to the verification of many numerical operations. The method of unitation is practically equivalent to the theory of congruencies, viz. the equa- tion U,;w=y would be written e=y (mod 6); and many of the results are iden- tical with those given by Gauss, On Many-valued Functions. By M,M.U. Witxiyson, M.A, GENERAL Puystcs, &c. On the Transformation of Gravity. By Tames Crom, F.RS.* On the Influence of the Residual Gas on the Movement of the Radiometer. By Witu1am Crooxns, FBS. The author's recent experiments show that the movement of this instrument is not due to a direct repulsion exerted by light on the vanes, but to a mutual action called out between these vanes and the very attenuated gas remaining in the instru- ment. . It is welllmown that, with a moderately good vacuum, the motion becomes more rapid as the exhaustion proceeds ; but he has recently succeeded in producing such a complete exhaustion that he not only reaches the point of maximum effect, but goes so far beyond it that the effect nearly ceases. The vacuum is measured by means of a special apparatus, in which 2 moving plate, instead of continuously rota- ting in one direction, as in the ordinary radiometer, is suspended by a glass fibre, which it twists in opposite directions alternately. The movement is started by rotating the whole apparatus through a small angle, and the observation consists ip noting the successive amplitudes of vibration when the instrument is left to itself, a mirror and spot of light being employed for this purpose. The amplitudes form a decreasing series, with a regular logarithmic decrement. The logarithmic decre- ment is nearly constant up to the point at which the vacuum is apparently equal to a Torricellian vacuum, the mercury in the gauge standing at the same height as a barometric column beside it; but as the exhaustion proceeds beyond this point, the logarithmic decrement becomes smaller—in other words, the amplitude diminishes less rapidly. By plotting the observations and supposing the curve continued, it is indicated that, if a perfect vacuum were attained, and the glass fibre had no visco- sity, the logarithmic decrement would be zero, we should have perpetual motion with constant amplitude, whilst, at the same time, the radiometer would cease to act. Other gases as well as air have been tried. Aqueous vapour is very unfavour- able to the action of the radiometer; hydrogen, on the contrary, gives the best result of all. Several experiments have been already described, which seem to oint to the true explanation of the action of the radiometer ; but the author thinks Mr, Stoney’s explanation the clearest. According to this, the repulsion is due to the internal movements of the molecules of the residual gas. When the mean length of path between successive collisions of the molecules is small compared with the dimensions of the vessel, the molecules, rebounding from the heated sur- face, and therefore moving with an extra Velocity, help to keep back the more * Printed én extenso in the Phil. Mag. 1876, ii p. 241, TRANSACTIONS OF THE SECTIONS. 81 slowly moving molecules which are advancing towards the heated surface; it thus happens that though the individual kicks against the heated surface are increased in strength in consequence of the heating, yet the number of molecules struck is diminished in the same proportion, so that there is equilibrium on the two sides of the disk, even though the temperatures of the faces are unequal. But when the exhaustion is carried to so high a point that the molecules are sufficiently few, and the mean length of path between their successive collisions is comparable with the dimensions of the vessel, the swiftly moving, rebounding molecules spend their force, in part or in whole, on the sides of the vessel, and the onward crowding, more slowly moving molecules are not kept back as before, so that the number which strike the warmer face approaches to, and in the limit equals, the number which strike the back, cooler face, and as the individual impacts are stronger on the warmer than on the cooler face, pressure is produced, causing the warmer face to retreat *. Mechanical Theory of the Soaring of Birds. By W. Frovpn, /.R.S. On the Passage of Fluids through Capillary and other Tubes. By Professor F. Gururim and Dr. F. Gurriz. On the Modification of the Motion of Waves produced by Fluid Friction. By Prof. J. Purser. On the Forces experienced by a Lamina immersed obliquely ina Fluid Stream. By Lord Rarreren, RS. On the Resistanez encountered by Vortex Rings, and the Relation between the Vortex Ring and Stream-lines of a Disk. By Prof, Osnorne Reynoxps. Description of the Bathometer. By Dr. C. W. Srumuns, FR. On the Amplitude of Waves of Light and Heat. By G. Jounstone Stoney, PRS. On Acoustic Analogues to Motions in the Molecules of Gases. By G. Jouystonz Srongy, PLS, Experimental IUustration of the Origin of Windings of Rivers in Alluwial Plains. By Professor James Tuomson, LL.D., D.Sc. The author referred to a communication which he had made to the Royal Society in the month of May last {, in which he had given a new theory of the flow of water round bends in rivers and round bends in pipes, and had explained the reason why, in alluvial plains, the bends of rivers go on increasing by the wearing away of the outer bank, and the deposition of mud, sand, and gravel on the inner * For further researches on this subject, see papers read before the Royal Society, November 16, 1876, and on April 26, 1877. + Printed im extenso in the Phil. Mag. 1876, ii. p. 480. t Proc, Roy, Soc, vol. xxv, p. 5. 32 REPORT—1876. bank, The theoretical view which he had then offered, he now, for the first time, had verified by practical experiment; and this experiment he showed in the meeting.. The chicf point of the new view now experimentally proved was that the water in turning the bend exerts centrifugal force, but that a thin lamina of the water at bottom, or in close proximity to the bed of the river, is retarded by friction with the river-bed, and so exerts less centrifugal force than do like portions of the oreat body of the water flowing over it in less close proximity to the river-bed. Consequently the bottom layer flows inward obliquely across the channel towards the inner bank, and rises up in its retarded condition between tke inner bank and the rapidly flowing water, and protects the inner bank from the scour, and brings with it sand and other detritus from the bottom, which it deposits along the inner bank. The apparatus showed a small river, about 8 inches wide and an inch or two deep, flowing round a bend, and exhibiting very completely the phenomena which had heen anticipated. On Metric Units of Force, Energy, and Power, larger than those on the Centi- metre-Gramn-Second System. By James Toomson, LL.D., D.Sc., PRSE., Professor of Civil Engineering and Mechanics in the University of Glasgow. The author premises that under the excellent method of Gauss for establishing units of force, a unit of force is taken as being the force which, if applied to a unit of mass for a unit of time, will impart to it a unit of velocity. In the system already adopted by the British Association Committee on Dynamical and Electrical Units (Brit. Assoc. Report, part i. 1873, page 222), the Centimetre, the Gram *, and the Second were taken as the units of length, of mass, and of time; and the unit of force thence derived under the method of Gauss was called the Dyne. That force is very small, quite too small for convenient use in all ordinary mechanical or engineering investigations. It is about equal to the gravity of a milligram mass, and that force is so small that it cannot be felt when applied to the hand. That system, designated as the Centimetre-Gram-Second System, recommended by the Committee of the British Association, and described fully, with many applications, in a book since published by Dr. Everett, who was Secretary to the Committee, is well suited for many dynamical and electrical pposes ; and it ought certainly to be maintained for use in all cases in which it is convenient. But the object of the present paper is to recommend the employ- ment also of two other systems which are in perfect harmony with it, and to propose names for the units of force under these two systems. In one of these systems, the Decimetre, the Kilogram, and the Second are the units adopted for length, mass, and time; and thus the system comes to be called the Decimetre-Kilogram-Second System. In the other, the Metre, the Tonne ft, and the Second are adopted as the units of length, mass, and time; and thus the system comes to be called the Metre-Toune- Second System. It is to be particularly observed that all the three systems here referred to are framed so as to attain the condition, very important for convenience, that the unit of mass adopted is the mass of a unit volume of water, and that, therefore, for every substance the specific gravity and the density, or mass per unit of volume, are made to be numerically the same. In the Decimetre-Kilogram-Second System, the unit of force derived by the method of Gauss is 10,000 Dynes, or is about equal to the gravity of 10 Grams, It is impossible, or almost so, to work practically with any such system without having a name for the unit of force. The unit of force in this system is such that a human hair is well suited for bearing it as a pull, with ample allowance of extra * The spelling Gram, instead of Gramme, for the English word is adopted in the present paper in accordance with the spelling put forward in the Metric Weights and Sener Act, 1864, which legalizes the use of the Metric System in Great Britain and reland. t+ The Tonne is the mass or quantity of matter contained in a cubie metre of water, and is very nearly the same as the British Ton. Ol —— Go TRANSACTIONS OF THE SECTIONS. DO strength for safety against breakage ; and the author proposes to call it the Crinal, from the Latin erinis and erinalis. d In the Metre-Tonne-Second System the unit of force, likewise derived by the Gaussian method, is 10,000 Crinals, or 100,000,000 Dynes, or is about equal to the gravity of 2 ewt., or of 7 ofa ton. This force would be properly borne as a pull by a moderately-sized rope; and the author proposes to call it the Puma, from the Latin fenis and funalis. Then we haye One Horse-Power, of 33,000 foot-pounds per minute, about equal to 75,000 Decimetre-Crinals per second; and the Horse-Power is also about equal to ‘75 of a Metre-Funal per second. Also 1 Metre-Funal = 100,000 Decimetre-Crinals, = 10,000,000,000 Centimetre-Dynes, or Irgs, = 101° Evgs. Also 1 Horse-Power is about = 7,500,000,000 Centimetre-Dynes per second, or as the same may be written 75 X 108 Centimetre-Dynes per second. The number 7,500,000,000, for expressing a Horse-Power under the Centimetre- Gram-Second System, is an exceedingly unmanageable one ; and it gives a very decisive indication that the Centimetre and Gram are too small to be suitable as fundamental units of length and of mass for ordinary engineering purposes ; and that there is great need for the establishment of systems having larger units, such as those which have been recommended in the present paper, and for which a con- yenient nomenclature has been offered. It is to be observed that the provision made’ by the British Association Com- mittee, in the Report already referred to, of a multiple of the Dyne, such as the Megadyne, or million of Dynes, as a larger unit of force, does not accomplish all that is to be desired, because various important formulas, or convenient methods of statement, will not hold good when any of the units are so derived. Thus, for instance, if the Megadyne be the unit of force, while the Gram and Second are the units of mass and time, the ordinary formulas for giving the so-called “ centrifugal force ’’ of a revolving mass, mv" s F=-- and F=mw*r, will not hold good; and, as another instance, we may notice that the proposition that, in respect to a jet of water, the reaction force on the vessel is equal numeri- cally to the momentum generated per second, will not hold good ; and numberless other instances might readily be cited, but those given may suffice, On the Precessional Motion of a Liquid. By Sir W. Tuomson, D.C.L., PRS, The formulas expressing this motion were briefly explained, but the analytical treatment of them was reserved for a paper ‘‘On the Nutation of a Solid Shell containing Liquid.” The chief object of the present communication was to illus- trate experimentally a conclusion from this theory which has been announced by the author in his opening address to the Section, to the effect that, if the period of the precession of an oblate spheroidal rigid shell full of liquid is a much greater multiple of the rotational period of the liquid than any diameter of the spheroid is of the difference between the greatest and least diameters, the precessional effect of a given couple acting on the shell is approximately the same as if the whole were a solid rotating with the same rotational velocity. The experiment consisted in showing a liquid gyrostat, in which an oblate spheroid of thin sheet-copper filled with water was substituted for the solid fly-wheel of the ordinary gyrostat. In the instrument actually exhibited the equatorial diameter of the liquid shell exceeded the polar axis by about one tenth of either. Supposing the rotational speed to be thirty turns per second, the effect of any motive which, if acting on a rotating solid of the same mass and dimensions, would produce a precession having its period a considerable multiple of 3 of a second, must, according to theory, produce very approximately the same precession in the thin shell filled with nad as in the rotating solid. Accordingly the main pre- 84 REPORT—1876. cessional phenomena of the liquid gyrostat were not noticeably different from those of ordinary solid gyrostats, which were shown in action for the sake of comparison. It is probable that careful observation without measurement might show very sen- sible differences between the performances of the liquid and the solid gyrostat in the way of nutational tremors produced by striking the case of the instrument with the fist. No attempt at measurement either of speeds or forces was included in the com- munication, and the author merely showed the liquid gyrostat as a rough general illustration, which he hoped might be regarded as an interesting illustration of that very interesting result of mathematical hydrokinetics, the quasi-rigidity produced in a frictionless liquid by rotation. P.S.—Since the communication of this paper to the Association, and the de- livery of my opening address which preceded it on the same day, I have received from Prof. Henry No. 240 of the ‘Smithsonian Contributions to Knowledge,’ of date October 1871, entitled “ Problems of Rotatory Motion presented by the Gyro- scope, the Precession of the Equinoxes, and the Pendulum,” by Brevet-Major Gen. J. G. Barnard, College of Engineers, U.S.A., in which I find a dissent from the portion of my previously published statements which I had taken the occasion of my address to correct, expressed in the following terms :— “T do not concur with Sir William Thomson in the opinions quoted in note, p. 38, from Thomson and Tait, and expressed in his letter to Mr. G. Poulett Scrope (‘ Nature,’ Feb. 1, 1872); so far as regards fluidity or imperfect rigidity, within an infinitely rigid envelope, I do not think the rate of precession would be affected.’ Elsewhere in the same paper Gen. Barnard speaks of “ the practical rigidity con- ferred by rotation.” Thus he has anticipated my correction of the statements con- tained in my paper on the rigidity of the earth, so far as regards the effect of inte- rior fluidity on the precessional motion of a perfectly rigid ellipsoidal shell filled with fluid. I regret to see that the other error of that paper which I corrected in my opening address had not been corrected by Gen. Barnard, and that the plausible reasoning which had led me to it had also seemed to him convincing. Tor myself I can only say that I took the very earliest opportunity to correct the errors after I found them to be errors, and that I deeply regret any mischief they may have done in the mean time. Addendum. Solid and Liquid Gyrostats.—The solid gyrostat has been regularly shown for many years in the natural philosophy class of the University of Glasgow as a me- chanical illustration of the dynamics of rotating solids, and it has also been exhibi- ted in London and Edinburgh at conversaziones of the Royal Societies and of the Society of Telegraph Engineers, but no account of it has yet been published. The following is a brief description of it. The solid gyrostat consists essentially of a massive fly-wheel, possessing great moment of inertia, pivoted on the two ends of its axis in bearings attached to an outer case which completely encloses it. Fig. 1 represents a section by a plane through the axis of the fly-wheel, and fig. 2 a section by a plane at right angles to the axis and cutting through the case just above the fly-wheel. The containing- case is fitted with a thin projecting edge in the plane of the fly-wheel, which is called the bearing-edge. Its boundary forms a regular curvilinear polygon of six- teen sides with its centre at the ceatre of the fly-wheel. Each side of the polygon is a small are of a circle of radius greater than the distance of the corners from the centre. The friction of the fly-wheel would, if the bearing-edge were circular, cause the case to roll along it like a hoop; and it is to prevent this effect that the curved polygonal form described above and represented in the drawing is given to the bearing-edee. To spin the solid gyrostat a piece of stout cord about forty feet long and a place where a clear run of about 60 feet can be obtained are convenient. The gyrostat having been placed with the axis of its fly-wheel vertical, the cord is passed in through an aperture in the case two and a half times round the bobbin-shaped part of the shaft and out again at an aperture on the opposite side. Haying taken | To face p. 34. Brit. Assoc. Rep., Trans. Sect. | FUG. a elon F, JIVCHES-———— =~ TRANSACTIONS OF THE SECTIONS. 35 care that the slack cord is placed clear of all obstacles, and that it is free from kinks, the operator holds the gyrostat steady, so that its case is prevented from turning, while an assistant pulls the cord through by running, at a gradually increasing pace, away from the instrument, while holding the end of the cord in his hand. Suffi- cient tension is applied to the entering cord to prevent it from slipping round on the shaft. In this way a very great angular velocity is communicated to the fly- wheel, sufficient, indeed, to keep it spinning for upwards of twenty minutes. Tf, when the gyrostat has been spun, it be set on its bearing-edge with the centre of gravity exactly over the bearing point, on a smooth horizontal plane such as a piece of plate-glass lying on a table, it will continue apparently stationary and in stable equilibrium. If while it is in this position a couple round a horizontal axis in the plane of the fly-wheel be applied to the wheel, no deflection of this plane from the vertical is produced, but it rotates slowly round a vertical axis. If a heavy blow with the fist be given to the side of the case, it is met by what seems to the senses the resistance of a very stiff elastic body, and, for a few seconds after the blow, the gyrostat is in a state of violent tremor, which, however, subsides rapidly. As the rotational velocity gradually diminishes, the rapidity of the tremors produced by the blow also diminishes. It is very curious to notice the tottering condition, and slow, seemingly palsied tremulousness of the gyrostat when the fly- wheel bas nearly ceased to spin. In the liquid gyrostat the fly-wheel is replaced by an oblate spheroid, made of thin sheet-copper and filled with water. The ellipticity of this shell in the in- strument exhibited is ;,—that is to say, the equatorial diameter exceeds the polar by that fraction of either. It is pivoted on the two ends of its polar axis in bear- ings fixed in a circular ring of brass surrounding the spheroid. This circle of brass is rigidly connected with the curved polygonal bearing-edge which lies in the equatorial plane of the instrument, thus forming a framework for the support of the spheroidal shell. In fig. 3 a section is represented through the polar axis to show the ellipticity, and fig. 4 gives a view of the gyrostat as seen from a point.in the prolongation of the axis. To prevent accident to the shell, when the gyrostat falls down at the end of its spin, cage-bars are fitted round it in such a way that no plane can touch the shell. The method of spinning the liquid gyrostat is similar to that described for the solid gyrostat, differing only in the use of a very much longer cord and of a large wheel for the purpose of pulling it. The cord is first wound on a bobbin free to rotate round a fixed pin. The end of it is then passed two and a half times round a little pulley, and thence to a point in the circumference of a large wheel to which it is fixed. An assistant then turns the wheel with gradually increasing velocity, while the frame of the gyrostat is firmly held, and the requisite tension applied to the entering cord to prevent it from slipping round the pulley. Secular Illustration of the Laws of the Diffusion of Liquids. By Sir W. Tuomson, D.C.L., FBS. On a new case of Instability of Steady Motion. By Sir W. Tuomson, D.C.L., F.RS. On the Nutation of a Solid Shell containing Liquid. By Sir W. Tomson, D.C.L., FBS. 36 REPORT—1876. Ligut AND Heat. Photometric Measurements of the Magneto-electric Light. By Captain Anney, F.B.S., Determination of the Conductivity of Heat by Water. By J. 'T. Borromnry. On the Testings of Large Objectives. By Howaxrp Gruss, Master of Engineering, Trinity College, Dublin. In the testing of large objectives, when the corrections haye been made to be very nearly perfect, a difficulty is sometimes felt in determining what, if any, corrections remain desirable, and also of determining in a simple way the amount of the desired alteration. For the chromatic aberration one plan often pursued by the optician is to slightly overcorrect the objective in the first instance, and then to separate the crown and flint (thus reducing the correction) until the best result is attained, when the amount of separation required becomes by a simple calculation a measure of the necessary alteration in the curves, This is an extremely useful practical arrangement; but unfortunately it is appli- cable to only one of the four possible errors, besides being troublesome and some- what dangerous in the case of large objectives. The desirability of some simple Ce of introducing, pro tempore, a small + or — effect of chromatic or spherical aberration, and of being able to accurately esti- mate the quantity of such, has been very apparent to me on several occasions; for I have frequently found the best judges of such matters differ in their estimate of final correction, and unable to agree thereon; and I have also often found a diffi- culty in satisfyg myself that the best balance of corrections had been attained ; whereas if it were possible to introduce a small amount, pyo tempore, of + or — correction, I could at once have perceived when I had overshot the mark. In fact the perfection of any correction in an objective means the best balance be- fween two opposing aberrations, and (just as in all cases of ascertaining balances) it is difficult to determine the neutral point unless there be the power of trying on both sides. To effect this, in preparing for the trial of the great objective for the new Obser- vatory at Vienna (of 27 inches aperture), I am constructing four lenses or combina~ tion of lenses capable of being mounted between the objective and ocular, and with a considerable range of motion in the axis of the telescope :— A, While it effects no other correction introduces a small amount of + chromatic aberration. JB. Similarly introduces a small amount of — chromatic aberration, C. S fp -+ spherical aberration. D. ff + — spherical aberration. The amount of any aberration introduced can be regulated by the position of the correcting lens in the pencil of rays. Now, knowing the construction of these combinations and their position in the encil of rays from objective to ocular, the corresponding correction in the objective is an easily calculable quantity. Quite apart from the use to the optician I believe the comfort of these appliances will be much appreciated by those appointed as judges, particularly where, as in the case of the Vienna telescope, the testing of the objective forms part of the work of a Committee composed ofa considerable number of Members. I have already experimented in this direction sufficiently to convince myself of the great value of this system so far as the correction for chromatic aberration is TRANSACTIONS OF THE SECTIONS. 37 concerned; but I have not as yet experimented on the spherical aberration, nor am I so sanguine of its success. There seems another direction in which a possible advantage might be gained by use of these correcting combinations, viz. in the case of minute stars whose light is made up for a great part of rays from either end of the spectrum, more particularly the blue end. It seems highly probable that better definition of these stars could be obtained if a slight temporary adjustment could be made in the chromatic correction suitable for that particular part of the spectrum from which the predominant light of the stars proceeds. OF course it is to be understood that the corrections here spoken of and proposed to be dealt with by their correcting lenses are only the very final ones—in fact, when the objective arrives at that degree of perfection in which it is almost impossible to say whether any improvement can be effected or not. On Recent Improvements in Equatorial Telescopes. By Howarp Gruss, Master of Engineering, Trinity College, Dublin. The author referred to former papers read by him at the Brighton and Belfast Meetings of the Association on the same subject, and proceeded to describe— Ist. A method of conveniently reading the R.A. circle from the eye-end of the telescope. 2nd. A new simple but effective arrangement for slow motion in R.A. ord. A new and very much improved form of clamping arrangement for both polar and declination axes. 4th. And a new method of controlling the uniform motion driving-clock of the telescopes from an ordinary sidereal clock by an electric current transmitted once a second from the sidereal clock; by which arrangement the driving-clock can be kept going continuously without the possibility of accumulation of errors beyond a small fraction of a second. On a Method of Photographing the Defects in Optical Glass arising from want of Homogeneity. By Howsarn Gruss, Master of Engineering, Trinity College, Dublin. The best practical method used for detecting in disks of optical glass defects arising from want of homogeneity is probably well known to many amateurs as well as to professional opticians. < The disk of glass to be examined should be either itself polished to a convex form, or, if that be not convenient, it should be placed in juxtaposition with a piece of glass which is known to be perfect and of such form as will render the combination of the two of convex power. A small light (say gas- or candle-flame, or any suf- ficiently brilliant light with a small diaphragm in front, see fig. 1) is placed at some Fig. 1. little distance, and the eye is placed in the conjugate focus formed by the lens of this light. The disk of glass should then appear brilliantly illuminated; but if the pupil of the eye is drawn slightly to one side, so that the pencil of light falls upon only one half of the pupil, immediately and most distinctly almost any want of homogencity is easily seen, ; : 88 REPORT—1876. 1 say “almost any want of homogeneity,” because, with one exception, I believe any kind can be detected; but I have met, very rarely, instances of one peculiar class of this defect which it is not possible to detect till the disk is actually worked into an objective: this happens when a slight gradual change of density occurs be- tween two portions of the disk with no abrupt line of separation between. Now this process, though a very simple one to a practised eye, is by no means so to an uneducated one ; and I have often desired a method by which I could graphi- cally represent those faults so that I might be able to communicate to others my ideas as to their exact forms and appearance, position in the disk, and so forth, and also to forma record of them. This, by a very simple contrivance, I have succeeded. in doing, and I am now able to photograph these defects in optical glass with per- fect certainty. : A glance at the diagram will suffice to show the principle by which this is effected. The eye in the first instance (that of eye observation, fig. 1) is replaced in the second case (fig. 2) by a photo-camera; and, with a little care in adjusting the image of diaphragm illuminated by a lamp on the diaphragm of photo-lens, very excellent photographs can be obtained. In fact the stop of the lens replaces the pupil of the eye, the photo-lens the crystalline lens, and the sensitized plate the retina. The defects arising from want of homogeneity in optical glass may be divided into three classes :— 1. Threads, or fine seams of some different quality of glass passing through the otherwise homogeneous disk, sometimes insignificant, sometimes long, but very rarely of any width. These are of but little importance. 2. Veins, or syrupy bands. These are portions of glass of differing and various densities not properly amalgamated together. Their appearance is that produced by adding a strong syrup solution to water. The forms of these veins are sometimes very fantastic. : This form of defect is very detrimental to the proper performances of the glass. drd, Sometimes, but very rarely (only four times in my experience), have I met with disks of glass having a density slightly different in different parts, without any well-defined line of demarcation between the different parts. This is most destruc- tive to its performance as an objective, and a most dangerous fault; for whereas in the two former cases the defects can be easily detected and even photographed, this third defect defies detection until the disks be formed into an objective. It is fortunate for opticians that this last defect is of such rare occurrence. The extreme usefulness of this simple device for photographing the defects in optical glass is self-evident. In the first place, faults can be detected by those whose eyes have not been suf- ficiently educated to perceive them by the old method; a record can be made of any remarkable defects; their appearance and form can be graphically repre- sented and described ; and, lastly, it can be ascertained by this process whether the veins are closer to one or other surfaces and are capable of being removed by grind- ing, a point which is very difficult indeed to ascertain otherwise. This last infor- mation is obtained by photographing the faults and then grinding off a small quan- tity, and rephotographing and comparing the photographs to see if any parts have disappeared. Many other useful purposes seem to be too self-evident to require mentioning. ——————<<— as ee TRANSACTIONS OF THE SECTIONS. 39 On the Decrease of Temperature with Height on the Earth’s Surface. ; By Professor Hunnessy, 1.5. If the air were perfectly still, the temperature at any point in the atmosphere would depend on its density, the heat absorbed from the solar rays, the heat ob- tained by convection from the earth, and the losses of heat by radiation. Of these the first has been almost exclusively considered. This is especially so in all investigations for the ascertainment of heights by the barometer. The exclu- sion of the other causes of variation of temperature with height may be admissible in considering the condition of a vertical column of air resting on a horizontal plane ; but the problem assumes a very different character when the decrease of tempera- ture with height along a very gradually sloping surface is considered. Such a surface is constantly communicating its temperature by convection currents to the overlying air, and the temperature of this air will depend on the extent, form, and pal roperties of the underlying surface. If we suppose a fat plain on the evel of the sea, an observer ina balloon at a height of 1000 feet would find the temperature almost unaffected by convection and dependent upon density. If, now, a steep mountain is superimposed on the plain and reaching to the observer, the conditions become altered. Ifa mountain of a gradual slope be superimposed, the alteration will be still greater; and if the entire plain were elevated up to 1000 feet so as to form an extensive tableland, the change of conditions would be very remarkable. It follows that the law of variation of temperature with height above the level of the sea cannot be considered as uniform. ‘The decrease is most rapid in going up through a vertical column of air, as in balloon ascents. It is slower along mountain sides, and slowest along gradually sloping plains or tablelands. From an examination of the records of many observations, it appears that the decrease of temperature in balloon ascents is nearly one degree Fahrenheit for 300 feet, while for tablelands it is so slow as from 590 to 800 feet for one degree. The author referred to a number of observations made in different countries con- firming the general conclusions to which he has been led. On the Distribution of Temperature over the British Islands. By Professor Hunnussy, /.2.S. The author referred to his former researches on the distribution of temperature oyer islands surrounded by heat-bearing currents and his demonstration that many of the isothermal lines in such islands must necessarily be closed curves*. He had originally illustrated his conclusions by the results of observations taken in the British Islands, and the isothermal lines laid down from such observations were found to be in perfect harmony with the law he had proved. In order to render this manifest he tabulated together the temperature of each, stating its latitude, longitude, height above the sea, and horizontal distance from the nearest sea coast. The actual temperature of any place is affected by all of these elements. In laying down the isothermal lines the actual temperatures unaltered by any so-called cor- rection for height were always employed. The stations were arranged according to temperature, and thus isothermal groups were immediately discovered, If the more recent collection of temperature results for the British Isles compiled by Mr. Buchan in the Journal of the Scottish Meteorological Society be treated in this way and the arbitrary and erroneous addition of 1° per every 300 feet in height be omitted, his results will conform to the law enunciated by the author. * See Brit. Assoc. Rep. 1857, pt. 2, p. 80; Atlantis, i. 1858, pp. 396-413; Phil. Mag. xvi. 1858, p. 241; Royal Society Proc. ix. p. 824; “On the Laws which regulate the Distribution of Isothermal Lines,” Atlantis, ii, p. 201; American Journal of Science, xxvii. p. 328. Copies of the temperature-maps are also partly reproduced in Report of Horti- cultural Congress at London in 1866; Journal of the R. Dublin Society, vol. for 1870-71 Report of the Commission on Oyster Fisheries, 1871. 40 REPORT—1876. Sur les Usages du Revolver Photographique en Astronomie et en Biologie. By Dr. J. Janssen. Photographies du Passage de Vénus &@ Kobé, By Dr. J. Janssen. Sur le Mirage en Mer. By Dr. J. Janssen. On Solar Photography, with reference to the History of the Solar Surface. By Dr. J. JANssen. On the Eclipse of the Sun observed at Siam in April 1875. By Dr. J. Janssen. On Rotation of the Plane of Polarization by Reflection from a Magnetic Pole. By Joun Kurr, LL.D., Mathematical Lecturer of the Free Church Training College, Glasgow*. In these experiments a beam of light is polarized by a first Nicol, reflected regu- larly from the end of an electromagnetic core of soft iron, and analyzed by a second Nicol. The magnetic force is concentrated intensely upon the mirror by means of a massive wedge of soft iron, which is separated from it by a narrow chink. The light is incident upon the polar mirror at an angle of 60° to 80°; the plane of polarization coincides with the plane of incidence; and the two Nicols are exactly crossed, so that the reflected light is extinguished by the second Nicol. First Experiment.—When the iron mirror is intensely magnetized as N. pole or S. pole, the light is distinctly restored from pure extinction, to disappear at once when the circuit of the magnetizing current is broken. ’ Second Experiment.—The first Nicol is turned from its initial position through an extremely small angle—(1) to the right, (2) to the left (from the point of inci- dence on the iron mirror as point of view), so that the reflected light is restored very faintly through the second Nicol. When the mirror becomes an intense S, pole, the effects of rotations (1) and (2) are strenethened and weakened respectively ; on the contrary, when the mirror becomes an intense N. pole, the effects of rota- tions (1) and (2) are weakened and strengthened respectively. In the two remaining experiments the optical effects of the preceding rotations (1) and (2) and of magnetizations 8. and N. of the mirror ave compensated sepa- rately. The compensator is a slip of plate-glass, held in a standard position between the mirror and the second Nicol and strained by the hands. The angle of incidence is about 75°. Third Experiment.—The first Nicol is turned from its initial position through an extremely small angle—(1) to the right, (2) to the left, so that the light is faintly restored from extinction by the second Nicol. The effects of displacement (1) and (2) are compensated, down to pure extinction, by tension and compression respectively. Fourth Experiment.—A repetition of the first, with addition of the compensator. The effects of magnetizations S. and N. of the mirror are compensated, down to pure extinction, by tension and compression respectively. The case of perpendicular incidence was tried carefully, but gave no good effect, the arrangements being comparatively imperfect. From the facts observed, it fol- lows evidently that when a beam of plane polarized light is reflected from a mag- netic pole, the plane of polarization is turned in the process of reflexion—to the left by a south-seeking pole, to the right by a north-seeking pole; so that in this * A full account of this investigation is given in the Phil. Mag., May 1877. TRANSACTIONS OF THE SECTIONS, 41 case of reflection from iron, as in most cases of transmission through salts of iron, the plane of polarization is turned in a direction contrary to that of the magne- tizing current. A Deseription of Spottiswoode’s Pocket Polarizing Apparatus. By W. Lapp. On a Phenomenon of Metallic Reflection. By Professor G,G.Sroxes, IRS. The phenomenon which I am about to describe was observed by me many years ago, and may not improbably have been seen by others; but as 1 have never seen any notice of it, and it is in some respects very remarkable, I think that a descrip- tion of it will not be unacceptable. When Newton’s rings are formed between a lens and a plate of metal, and are viewed by light polarized perpendicularly to the plane of incidence, we know that, as the angle of incidence is increased, the rings, which are at first dark- centred, disappear on passing the polarizing angle of the glass, and then reappear white-centred, in which state they remain up to a grazing incidence, when they can no longer be followed. At a high incidence the first dark ring is much the most conspicuous of the series. To follow the rings beyond the limit of total internal reflection we must employ a prism. When the rings formed between glass and glass are viewed in this way, we know that as the angle of incidence is increased the rings one by one open out, uniting with bands of the same respective orders which are seen beneath the limit of total internal reflection ; the limit or boundary between total and partial reflection passes down beneath the point of contact, and the central dark spot is left isolated in a bright field. Now when the rings are formed between a prism with a slightly convex base and a plate of silver, and the angle of incidence is increased so as to pass the cri- tical angle, if common light be used, in lieu of a simple spot we have a ring, which becomes more conspicuous at a certain angle of ineitlones well beyond the critical angle, after which it rapidly contracts ard passes into a spot. As thus viewed the ring is, however, somewhat confused. To study the pheno- menon in its purity we must employ polarized light, or, which is more convenient, analyze the reflected light by means of a Nicol’s prism. When viewed by light polarized in the plane of incidence, the rings show nothing remarkable. They are naturally weaker than with glass, as the interfering streams are so unequal in intensity. They are black-centred throughout, and, as with glass, they open out one after another on approaching the limit of total reflection and disappear, leaving the central spot isolated in the bright field beyond the limit, The spot appears to be notably smaller than with glass under like conditions, With light polarized perpendicularly to the plane of incidence, the rings pass from dark-centred to bright-centred on passing the polarizing angle of the glass, and open out as they approach the limit of total reflection. ‘The last dark ring to disappear is not, however, the first, but the second. The first, corresponding in order to the first bright ring within the polarizing angle of the glass, remains 1s0- lated in the bright field, enclosing a relatively, though not absolutely, bright spot. At the centre of the spot the glass and metal are in optical contact, and the reflection takes place accordingly and is not total. The dark ring, too, is not absolutely black. As the angle of internal incidence increases by a few degrees, the dark ring undergoes a rapid and remarkable change. Its intensity increases till (in the case of silver) the ring becomes sensibly black; then it rapidly contracts, squeezing out, as it were, the bright central spot, and forming itself a dark spot, larger than with glass, isolated in the bright field. When at its best it is distinctly seen to be fringed with colour, blue outside, red inside (especially the former), showing that the seale of the ring depends on the wave-length, being greater for the less refran- gible colours. This rapid alteration taking place well beyond the critical angle is very remarkable. Clearly there is a rapid change in the reflective properties of the metal, which takes place, so to speak, in passing through a certain angle determined by a sine greater than unity. 1876, L 42 REPORT—1876. I have described the phenomenon with silver, which shows it best ; but speculum- metal, gold, and copper show it very well, while with steel it is far less conspicuous. When the coloured metals geld and copper are examined by the light of a pure spectrum, the ring is seen to be better formed in the less than in the more refran- gible colours, being more intense when at its best ; while with silver and speculum- metal there is little difference, except as to size, in the different colours, Hzematite and iron pyrites, which approach the metals in opacity and in the change of phase which they produce by reflection of light polarized parallelrelatively to light polarized perpendicularly to the plane of incidence, do not exactly form a ring isolated in a bright field ; but the spot seen with light polarized perpendicularly to the plane of incidence is abnormally broad just about the limit of total reflection, and rapidly contracts on increasing the angle of incidence. It seemed to me that a sequence may be traced from the rapidly contracting rings of diamond seen in passing the polarizing angle of that substance, through the abnormally broad and rapidly contracting spot seen with iron pyrites just about the limit of total reflection, and the somewhat inconspicuous ring of steel seen a little beyond the limit, to the intense rapidly contracting ring of silver seen consi- derably beyond the limit. If so, the full theory of the ring will not be contained in the usually accepted formule for metallic reflection, modified, as in the case of transparent substances, in accordance with the circumstance that the incidence on the first surface of the plate of air is beyond that of total reflection. MacCullagh was the first to obtain the formule for metallic reflection, showing that they were to be deduced from Fresnel’s formule by making the refractive index a mixed imaginary, though they are usually attributed to Cauchy, who has given formule differing from those of MacCullagh merely in algebraic detail. As regards theory, Cauchy made an important advance on what MacCullagh had done in connecting the peculiar optical properties of metals with their intense ab- sorbing power*. Now Fresnel’s formule do not include the phenomena discovered by Sir eens Airy, which are seen in passing the polarizing angle of diamond, and which have been more recently extended by M. Jamin to the generality of transparent substances; and if these pass by regular sequence to those I have de- scribed as seen with metals beyond the limit of total internal reflection, it follows that the latter would not be completely embraced in the application of Fresnel’s formule, modified to suit an intensely absorbing substance and an angle of inci- dence given by a sine greater than unity T. ELECTRICITY. On the Contact Theory of Voltaic Action. By Professors Ayrton and Perry. On a new Form of Electrometer. By Prof. J. Dewar, F.R.S.L. On a Mechanical Illustration of Electric Induction and Conduction. By Oxrver J. Loner, B.Sc. The paper describes the construction of a model which illustrates Prof. Clerk Maxwell’s theory of electric action on the hypothesis of stress in a dielectric me- * The apparent difference between MacCullagh and Cauchy as to the values of the refractive indices of metals is merely a question of arbitrary nomenclature. t It was long ago observed, both by Professor MacCullagh and Dr. Lloyd, that when Newton’s rings are formed between a glass lens and a metallic plate, the first dark ring sur- rounding the central spot, which is comparatively bright, remains constantly of the same size at high incidences, although the other rings, like Newton’s rings formed between two glass lenses, dilate greatly as the incidence becomes more oblique. See ‘ Proceedings of the Royal Irish Academy,’ yol. i. p. 6. TRANSACTIONS OF THE SECTIONS. 43 dium, and which consists essentially of an endless cord passing with friction through buttons supported on elastic strings. By altering the relation between the friction and the camel of different parts, it can be made to exhibit very com- letely the phenomena observed when an electromotive force is made to act :—(1) ieiwenn the ends of a metal wire; (2) through an electrolytic liquid, when it illustrates the convection of electricity by the cathion and the polarization of the electrode; (3) in an accumulator with perfectly insulating dielectric, when it shows the polarization of the dielectric, the displacement of electricity in the direction of the force, the tension along the lines of force, occasional possible disruptive dis- charge, and consequent possible internal charge; (4) across a dielectric which is homogeneous, but has a slight conducting power, showing in this case a continuous ordinary conduction-current, in addition to the variations of electric displacement ; (5) across a non-homogeneous or stratified dielectric, in which a “ residual charge,” is possible. If made of proper materials, the model would exhibit this residual charge quantitatively as well as qualitatively ; and, in fact, the investigation “ On the Theory of a Composite Dielectric” (in arts. 328-330 of Maxwell’s ‘ Electricity’) would apply to it with little modification. It further illustrates incidentally the action of a voltaic cell and of a submarine cable. On a Mechanical Illustration of Thermoelectric Phenomena. By Outvrr J. Loven, B.Se. The model which illustrates metallic conduction in the preceding communica- tion is supposed to be modified, so that all the buttons execute very rapid isochro- nous simple harmonic motions, sliding to and fro on the cord. The rate of cooling of a body placed in an enclosure at absolute zero is then seen to be proportional to the absolute temperature of the body, and to depend on its specific electrical resist- ance, The electric condition of tourmaline is explained by an hypothesis as to the nature of its internal structure ; and the amount of heat generated by an electric current passing through a metallic conductor is deduced in accordance with Joule’s law. An hypothesis is then started as to the nature of the internal actions at a junction either of two different metals at the same temperature or of two parts of the same metal at different temperatures ; and, on the strength of this hypothesis, electromotive force produced by contact, the Peltier effect, and Thomson’s electric convection of heat are all illustrated. The exact laws which have been experi- mentally established for these effects may possibly be deducible from considerations founded on the model ; but this has not yet been properly done*, On the Protection of Buildings from Lightning. By Professor J. Currx Maxwett, /.2.S. Most of those who have given directions for the construction of lightning- conductors have paid great attention to the upper and lower extremities of the conductor. They recommend that the upper extremity of the conductor should extend somewhat above the highest part of the building to be protected, and that it should terminate in a sharp point, and that the lower extremity should be car- ried as far as possible into the conducting strata of the ground, so as to “ make” what telegraph engineers call “a good earth.” The electrical effect of such an arrangement is to tap, as it were, the gathering charge, by facilitating a quiet discharge between the atmospheric accumulation and the earth. The erection of the conductor will cause a somewhat greater number of discharges to occur at the place than would have occurred if it had not been erected, but each of these raahanees will be smaller than those which would have occurred without the conductor. It is probable, also, that fewer discharges will occur in the region surrounding the conductor. It appears to me that these arrange- ments are calculated rather for the benefit of the surrounding country, and for the * These two papers are published, with some additions, in the Phil. Mag. ser. 5, vol. ii. pp. 353 and 524. 4* AA, REPORT—1876. relief of clouds labouring under an accumulation of electricity, than for the pro- tection of the building on which the conductor is erected. What we really wish is to prevent the possibility of an electric discharge taking place within a certain region, say, the inside of a gunpowder manufactory. If this is clearly laid down as our object, the method of securing it is equally clear. An electric discharge cannot occur between two bodies unless the difference of their potentials is sufficiently great compared with the distance between them. If, therefore, we can keep the potentials of all bodies within a certain region equal or nearly equal, no discharge will take place between them. We may secure this by connecting all these bodies by means of good conductors, such as copper-wire ropes ; but it is not necessary to do so; for it may be shown by experiment that if every part of the surface surrounding a certain region is at the same potential, every oint within that region must be at the same potential, provided no charged body is placed within the region. It would therefore be sufficient to surround our powder-mill with a conductin material (to sheathe its roof, walls, and ground-floor with thick sheet-copper), an then a electrical effect could eccur within it on account of any thunder-storm outside. There would be no need of any earth-connexion. We might even place a layer of asphalt between the copper floor and the ground, so as to insulate the building. If the mill were then struck with lightning, it would remain charged for some time, and a person standing on the ground outside and touching the wall might receive a shock ; but no electrical effect would be perceived inside, even on the most delicate electrometer. The potential of every thing inside, with respect to the earth, would be suddenly raised or lowered, as the case might be; but electric potential is not a physical condition, but only a mathematical conception, so that no physical effect could be perceived. It is therefore not necessary to connect large masses of metal, such as engines, tanks, &c., to the walls, if they are entirely within the building. If, however, any conductor, such as a telegraph-wire or a metallic supply-pipe for water or gas, comes into the building from without, the potential of this conductor may be different from that of the building, unless it is connected with the conducting shell of the building. Hence the water or gas supply-pipes, if any enter the building, must be connected to the system of lightning-conductors ; and since to connect a telegraph-wire with the conductor would render the telegraph useless, no telegraph from without should be allowed to enter a powder-mill, though there may be elec- tric bells and other telegraphic apparatus entirely within the building. I have supposed the powder-mill to be entirely shéathed in thick sheet-copper. This, however, is by no means necessary in order to prevent any sensible electric effect taking place within it, supposing it struck by lightning. It is quite sufficient to enclose the building with a network of a good conducting substance. For in- stance, if a copper wire, say No. 4, B.W.G. (0-238 inch in diameter), were carried round the foundation of a house, up each of the corners and gables, and along the ridges, this would probably be a sufficient protection for an ordinary building against any thunder-storm in this climate. The copper wire may be built into the wall to prevent theft, but it should be connected to any outside metal, such as lead or zine on the rovf, and to metal rain-water pipes. In the case of a powder-mill, it might be advisable to make the network closer by carrying one or two additional wires over the roof and down the walls to the wire at the foundation. If there are water- or gas-pipes which enter the building from without, these must be connected with the system of conducting-wires ; but if there are no such metallic connexions with distant points, it is not necessary to take any pains to facilitate the escape of the electricity into the earth. It is desirable, however, to provide for the safety not only of the building itself, but of the system of conductors which protects it. The only parts of this system which are in any danger are the points where the electricity enters and leaves it. If, therefore, the system terminates above in a tall rod with a sharp point, and downwards in an “earth wire,” the external discharge will be almost certain to occur at the ends of these electrodes, and the only possible damage will be the loss TRANSACTIONS OF THE SECTIONS. 45 of a few particles from their extremities; but even if the rod and wire were de- stroyed altogether, the building would still he safe, On Compass Correction in Ivon Ships. By Sir W. Tuomsoy, D.C.L., PRS, Effects of Stress on the Magnetization of Iron. By Sir W. Tuomson, D.C.L., PRS, On Contact Electricity. By Sir W. Tuomsoy, D.C.L., PRS, ACOUSTICS, On the Conditions of the Transformation of Pendulum-Vibrations ; with an experimental illustration. By R. H. M. Bosangver, Fellow of St. John's College, Oxford. Under certain circumstances, a pendulum-vibration of given period can give rise to impulses which support vibrations whose periods are 3, 3) 4) ++ +++ of the period of the original vibration. The conditions under which this takes place are of interest. Wheatstone enunciated the following as an experimental law :—A periodic im~- pulse can sustain vibrations whose frequencies are multiples of that of the impulse. This was supported by an experiment in which the harmonics of a Jew’s harp are obtained from it by an adjustable resonator. But a general law cannot be proved by a particular ae An experiment was adduced in contradiction of the generality of the above law. Tt can be shown that the stopped pipes of the organ are incapable of supporting the vibration of resonators tuned to their octave and double octave, while open pipes are capable of doing so. As the result of mechanical theory, the law may be enunciated that no pendulum- vibration can be maintained in a vibrating system, unless the acting forces contain pues of the same period as the vibration maintained. he experiments commonly shown, in which a simple pendulum-vibration is made to support its harmonics, generally depend on a transformation of the vibra- tion in the-transmission of the impulse. The apparatus exhibited forms a type of the general process of transformation by transmission. A metronome vibrating seconds furnishes the fundamental vibration: a number of smal] pendulums vibrate 2, 3, 4, 5, 6, 7, and 8 times in a second. By making connexions between the metronome and the pendulums with elastic cord in diffe~ rent ways, the different kinds of transmission (with and without transformation) can be illustrated. When the cord is tight, the impulses are transmitted without transformation ; when the cord goes slack during the vibration, the impulses are transformed into a series of pulls. In the first case the small pendulums are not affected ; in the second they are generally set in vibration. The following points are illustrated by the experiment with the partly slack cord, where the impulses constitute a series of pulls :— The common exposition of the theory of musical sounds, in which the impulses are compared to the blows of a hammer, really makes a very complex effect the basis of operations. The notes thus constructed differ from simple musical tones in having the power of supporting the vibrations of their harmonics. The cases of the notes of the siren and the harmonium, in which the sound is produced by a series of jets of air, are illustrated by the same experiment. An experiment of Prof. Mayer's, for the analysis of the sound of a reed pipe, by 46 REPORT—1876. attaching a vibrating portion of it to tuning-forks, was discussed. It was shown that the mode of transmission is such as to lead to transformation, whereby the analysis is vitiated. Mr. J. Baillie Hamilton’s experiment, in which an harmonium-reed is made to support the vibrations of a wire sounding its harmonics without actual attachment, was shown to be a case of transformation. The production of harmonics by resonance from the Jew’s harp or harmonium- reeds without wind was discussed ; and it was shown that they may be regarded as giving rise to discontinuous impulses at the moment when they close the open- ings in which they fit. It was then shown how a series of discontinuous impulses may be expressed mathematically; and from the fact that the expressions involve pendulum-yibrations corresponding to the harmonics, it was shown to follow that harmonic vibrations may be excited by such a series of impulses. The nature of the modification the expressions require for application to the siren was pointed out, and it was thus explained how the siren tone comes to involve harmonics of considerable intensity. We now come to the problem of transformation of simple-sound vibrations by transmission through air. An experiment was described in which a large tuning-fork was presented to a series of resonators (organ-pipes) tuned to its harmonics; the result was that, with the fork alone, they were audible up to the tierce inclusive (harmonic of fifth order), and with a disk of wood fastened on to the prong they were audible up to the harmonic seventh inclusive. A mathematical investigation of the transformation of simple vibrations in air was then carried out, and applied to the above experiment. It results that for the fifth harmonic of the fork, which was clearly heard, the flow of energy should be approximately j 2x 1018 This seeming extraordinarily minute, an experiment was made with a small tuning- fork of about the same pitch as the fifth harmonic above mentioned. The time of diminution of the amplitude to ;, was observed and the initial amplitude. From this the amplitude was calculated at the subsequent time when the sound just ceased to be audible. The flow of energy per second at this point was estimated approximately at ; 4x 1018 which agrees pretty well with the above number deduced from theory, It was then pointed out that the intensity due to a given flow of energy is diffe- rent in different parts of the scale. Helmholtz has remarked this (p. 264 of Ellis’s Helmholtz); and, in a paper in the ‘Philosophical Magazine’ (Nov. 1872), the writer showed that, if we admit that in similar organ-pipes similar proportions of the energy of the wind supplied are converted into sound, the mechanical energy of notes of given intensity varies inversely as the vibration number, a law in accordance with the indications given by Helmholtz. The theory was then applied to ascertain the extent of the development of har- monics in a tubular resonator tuned to the fundamental. Such development turns out to be very considerable. In consequence of this we cannot generally assume that the notes produced by resonators are simple tones. The bearing of this on a recent important paper of Kcenig’s was alluded to. foot pounds per second. foot pounds, True Intonation, illustrated by the Voice-Harmonium with Natural Finger- board. By Corin Brown. A series of harmonics forms an arithmetical progression, the number of the vibrations between any consecutive members of the series being equal. The vibra- tions rapidly increase in velocity in the higher harmonics, while the musical inter- TRANSACTIONS OF THE SECTIONS. 4.7 vals as rapidly decrease: the same number of vibrations which between the 1st and 2nd steps of the harmonic series produce an octaye, between 2nd and 3rd step a fifth, between the 4th and 5th steps a major third, between the 15th and 16th steps produce only a diatonic semitone, and so onwards beyond the range of musical computation. In contrast with this harmonic series of sounds, which is simple, arithmetical, and perfectly regular, we have the series of the musical scale, which is compound, geometrical, and so irregular that two tones or steps of equal vibrations cannot musically succeed each other. Of the 48 sounds in the harmonic series, 22 are coincident with the musical series, and 26 are not coincident. Of these 22 coincidences, the root, or lowest sound of the harmonic series, occurs as— The 4th sound of the musical scale........ 6 times. The Ist sound, or Tonic, occurs ........+- 5 yy The Gth ,, ofthe scale ,, .....ssseeee AL ss The 5th ,, + aie Beiten sresisiaie We Bie The 3rd__,, - ian PAS beopa siete £3 ae] ori The 2nd _,, is By MTD WaxieRereOEhe eae The 7th ,, *; wa ey ate aoa Mh st She ers Ancall es ere a Dah Of these 22 coincidences between the harmonic series and the musical series, the last are the numbers 24, 27, 30, 32, 36, 40, 45, and 48, which form the relations of the musical scale. This full harmonic series can only be built upon Fa, or the 4th of the musical scale, as its root ; and the first power of Fa, 102 (as it appears in the lowest series of the musical scale 8, 9, 10, 102, 12, 133, 15, 16), is the common multiplier and divisor of the vibrations of all the sounds of the musical scale. Thus in the octave from tenor C upwards the vibrations are :— Cc D E F G A B Cc 256, 288, 920, 3412, 884, 4963, 480, 412. These, divided by the first power of Fa, or the 4th of the musical scale (say 103), give 24, 27, 30, 32, 36, 40, 45, 48, being the figures of the musical scale with which the harmonic series closes. In this harmonic series the 8th, 9th, and 10th tones or steps following in diatonic succession are the Ist, 2nd, and 3rd tones of the musical scale, and the 15th and 16th _are the 7th and 8th of the musical scale. These figures give us the first or lowest relations of the musical scale, 8:9, 9: 10, and 15:16 :— The large step or tone of 8: 9 occurs 3 times. The less Fr of SAO ce aes. The small _,, or LS GR re cams Within the octave, inall,..... 7 steps or tones. These relations of the tones or steps of the scale are always the same in every key. C, =512 vibrations, is common to the keys of Bp, F, C, and G; and the 7th or diatonic semitone below, =480 vibrations, is common to the keys of C, G, and D; so with every musical tone. Each of these is represented. by a digital upon the natural finger-board of the author’s voice-harmonium. For distinction the digitals representing tones common to 4 keys are white, those to 3 keys are coloured; the Ist, 2nd, 4th, and 5th tones of the scale in every key are white, and the 3rd, 6th, and 7th are coloured. In every key, looking along the fingerboard, the progression of the scale is the same :—8:9, 9:10, 15:16, 8:9, 9:10, 8:9, 15:16. From white digital to white, or from coloured to coloured, there is always the large step or tone of the scale 8:9; from white to coloured always the less tone of the scale 9:10; and from coloured to white always the small step or tone 15 : 16, the diatonic semitone, Looking across the finger-hoard at the digitals endwise, from the end of each white 48 REPORT—1876, digital to the end of the coloured immediately above it in direct line there is always the chromatic semitone of 128:135, and from the end of each coloured digital to the end of the white immediately above the comma of 80: 81 always appears. eaiean each white or flat note, as Ep, and each coloured or sharp note, as Dz, at the distance of six removes looking across the diagram or finger-board, the schisma of the scale is always found, 32,768: 32,805. The only other relation of the scale is represented by a round digital on the finger-board and by 7 minor on the diagram ; it is tuned as 15: 16, to the 6th of the major scale, and supplies the sharpened 7th and 6th tones of the modern minor scale ; it also gives the imperfect chromatic semitone of 24:25 in relation to the 5th of the major scale, This finger-board is termed “ natural ” because no extra digitals like the five black digitals of the ordinary keyboard are required to produce the chromatic tones. Every coloured digital is sharp in relation to the white below it; and every white digital is flat in relation to the coloured above it, the relation being always 128: 135. On this finger-board only 4 musical relations, viz. 8:9, 9:10, 15:6, and 128: 135, are found, and 3 musical differences, viz. 24: 25, 80:81, and 32,768 : 32,805. All the larger intervals of the scale are formed by adding 8:9, 9:10, and 15:16 together, and all the smaller intervals are produced by subtracting or dividing these, thus :— &: 9 less 15:16 128: 135, the chromatic semitone ; O1100.)) Abid 24:25, the imperfect chromatic semitone ; Seamer LO 80:81, the comma; and Sik Olean. LO 128: 185, which being squared and divided by 9:10, gives the schisma 32,768 : 382,805. Thus all the in- tervals and relations of the musical scale proceed from these three simple elements, 8:9, 9:10, and 15: 16. By adding a comma and aschisma together, the comma of Pythagoras is produced. This is always found between keys changed enharmonically, as from C h to B. The three series of digitals upon this finger-board, white, coloured, and round, are very easily tuned by perfect fifths throughout, and connected together by major thirds, The tuning is diagonal, producing every interval perfectly in its proper place. Tuned in this way, this instrument (within its range or compass) is mathemati- cally and musically perfect, without compromise or approximation of any kind, and requiring neither equations, decimals, nor logarithms to explain it. It is very easily played upon*, On a Practical Method of Tuning a Major Third. By Sir W. Tuomson, D.C.L., FBS. InstRruMeEnts, &c. On a Form of Gasholder giving a uniform Flow of Gas. By Prof. Barrzrr. Diagrams and Description of the new Lecture-Table for Physical Demonstration in the Royal College of Science for Ireland, By Prof. Barrurr. Two new Forins of Apparatus for the Experimental Illustration of the Expan- sion of Solids by Heat. By Prof. Barxerr. * The principles of construction, tuning, &c. of the voice-harmonium will be found fully explained in ‘ Music in Common Things,’ part ii. Collins and Co,: London, Hdin- burgh, and Glasgow, TRANSACTIONS OF THE SECTIONS. 49 -On a Modification of the Sprengel Pump, and a new Form of Vaouum-Tap. By C,H. Grarnenam, On new Standards of Measure and Weight. By Prof. Hennussy, PRS. On a new Form of Thermometer for observing Earth Temperature. By G. J. Symons, On an Unmistakable True North Compass. By G. J. Symons. The author said that it was not generally known, except to nautical and to scientific men, that the compasses usually sold did not point to the true North or South Pole of the earth. The magnetic Pole, to which all compass-needles pointed, was not identical with the geographical pole, which was the north point of maps. The variation of the needle was considerable, and was no doubt often the cause of tourists losing their way. The difference between true and magnetic north was not the same in all parts of the United Kingdom, and 4 fortioré in all parts of the globe, nor was it absolutely the same from year to year. One of the advantages of these instruments was their pointing to the true north, the other was their “unmistakableness.” These compasses were corrected for use in the United Kingdom, but could be adapted to any specified locality in any part of the world. On a new Form of Astronomical Clock with Free Pendulum and Indepen- dently Governed Uniform Motion for Escapement-wheel. By Sir W. Tuomson, D.C.L., PRS. The object of this communication was to explain to members of the Association and give them an opportunity of seeing in the author's house in the University a clock which had been described in a communication to the Royal Society, in 1869, entitled “Ona New Astronomical Clock and a Pendulum Governor for Uniform Motion.” The following description is taken from the ‘ Proceedings of the Royal Society’ for 1869, except a few alterations and additions and the drawings, which have not been hitherto published :— It seems strange that the dead-beat escapement should still hold its place in the astronomical clock, when its geometrical transformation, the cylinder escapement of the same inventor, Graham, only survives in Geneva watches of the cheaper class. For better portable time-keepers it has been altered through the vicious rack-and- pinion movement into the superlatively good detached lever. If it is possible to make astronomical clocks go better than at present by merely giving them a better escapement, it is quite certain that one on the same principle as the detached lever, or as Earnshaw’s ship-chronometer escapement, would improve their time-keeping. But the irregularities hitherto tolerated in astronomical clocks may be due more to the faultiness of the steel and mercury compensation pendulum, with its loosely attached glass jar, and of the mode in which it is hung, and of the instability of the supporting clock-case or framework, than to imperfection of the escapement and the greatness of the are of vibration which it requires; therefore it would be wrong to expect confidently much improvement in the time-keeping merely from improvement of the escapement. I have therefore endeavoured to improve both the compensation for change of temperature in the pendulum, and the mode of its support, in a clock which I haye recently made with an escapement on a new prin- ciple, in which the simplicity of the dead-beat escapement of Graham is retained, while its great defect, the stopping of the whole train of wheels by pressure of a tooth upon a surface moving with the pendulum, is remedied. Imagine the escapement-wheel of a common dead-beat clock to be mounted on a collar fitting easily upon a shaft, instead of being rigidly attached to it. Let friction be properly applied between the shaft and the collar, so that the wheel shall be earried round by the shaft unless resisted by a force exceeding some small definite 50 REPORT—1876. amount, and let a governor giving uniform motion be applied to the train of wheel- work connected with this shaft, and so adjusted that, when the escapement-wheel is unresisted, it will move faster by a small eee than it must move to keep time properly. Now let the escapement-wheel, thus mounted and carried round, act upon the escapement, just as it does in the ordinary clock. It will keep the pendulum vibrating, and will, just as in the ordinary clock, be held back every time it touches the escapement during the interval required to set it right again from haying gone too fast during the preceding interval of motion. But in the ordinary clock the interval of rest is considerable, generally greater than the inter- val of motion. In the new clock it is equal to a small fraction of the interval of motion—,;}, in the clock as now working, but to be reduced probably to something much smaller yet. The simplest appliance to count the turns of this escapement- wheel (a worm, for instance, working upon a wheel with thirty teeth, carrying a hand round, which will correspond to the seconds hand of the clock) completes the instrument; for minute-and hour-hands are a superfluity in an astronomical clock. In various trials which I have made since the year 1865, when this plan of es- capement first occurred to me, I have used several different forms, all answering to the preceding description, although differing widely in their geometrical and me- chanical characters. In all of them the escapement-wheel is reduced to a single tooth or arm, to diminish as much as possible the moment of inertia of the mass stopped by the pendulum. This arm revolves in the period of the pendulum (two seconds for a seconds pendulum), or some multiple of it. ‘Thus the pendu- lum may execute many complete periods of vibration without being touched by the escapement. In all my trials the pallets have been attached to the bottom of the pendulum, projecting below it, in order-that satisfactory action with a very small are of vibration (not more on each side than 3, of the radius, or 1 centi- metre for the seconds pendulum) may be secured. In the clock in my house the seconds pendulum of the fine movement vibrates with great constancy through half a millimetre, that is to say, through an are of 1, of the radian on each side of the vertical. This, I believe, is the smallest range that has hitherto been realized in any seconds pendulum of an astronomical or other clock. In the drawing s represents the vertical escapement-shaft, round which is fitted loosely B the collar c, carrying the worm v. The small wheel, d, is worked by v, and carries round the seconds hand of the clock. a repre- sents a piece of fine steel wire, being the single arm to which the teeth of the escapement- wheel are reduced in the clock described in this paper; pp the pallets attached to bars projecting downwards from the bob, B, of the pendulum ; 7, a foot bearing the weight of the collar-worm and escapement-tooth. The bar connecting f with the collar is of such a length as to give a proper moment to the frictional force by which the collar is carried round. The shaft s carries a wheel, represented in section by ww, which is driven by a train of wheel-work (not shown in the drawing) from the governor. This wheel is made to go 1 per cent. faster than once round in two seconds, while the peaduluea prevents the collar from going round more than once in two seconds. My trials were rendered practically abortive from 1865 until a few months ago by the difficulty of obtaining a satisfactory governor for the uniform motion of the escapement- shaft; this difficulty is quite overcome in the pendulum governor, which I now proceed to describe. - TRANSACTIONS OF THE SECTIONS. 51 Imagine a pendulum with single tooth escapement mounted on a collar loose on the escapement-shaft just as described above, the shaft being vertical in this case also, A square-threaded screw is cut on the upper quarter of the length of the shaft, this being the part of it on which the escapement-collar works; and a pin fixed to the collar projects inwards to the furrow of the screw, so that, if the collar is turned relatively to the shaft, it will be carried along as the nut of a screw, but with less friction than an ordinary nut. Below the screw and long nut-collar three-quarters of the length of the escapement-shaft is surrounded by a tube which by wheel-work is carried round about 5 per cent. faster than the central shaft. This outer shaft, by means of friction produced by the pressure of proper springs, carries the nut-collar round along with it, except when the escapement-tooth is stopped by either of the pallets attached to the pendulum. A stiff cross-piece (like the head of a T), projecting each way from the top of the tubular shaft, carries, hanging down from it, the governing masses of a centrifugal friction governor. These masses are drawn towards the axis by springs, the inner ends of which are acted on by the nut-collar, so that the higher or the lower the latter is in its range the springs pull the masses inwards with less or more force. A fixed metal ring coaxial with the main shaft holds the governing masses in when their centrifugal forces exceed the forces of the springs, and resists the motion by forces of friction increasing approximately in simple proportion to the excess of the speed above that which just balances the forces of the springs. As long as the escapement-tooth is unresisted the nut-collar is carried round with the quicker motion of the outer tubular shaft, and so it screws upwards, diminishing the force of the springs. Once every semiperiod of the pendulum it is held back by either pallet, and the nut-col- lar screws down as much as it rose during the preceding interval of freedom, when the action is regular; and the central or main escapement-shaft turns in the same period as the tooth, being the period of the pendulum. If through increase or diminution of the driving-power, or diminution or increase of the coefficient of friction between the governing masses and the ring on which they press, the shaft tends to turn faster or slower, the nut-collar works its way down or up the screw, until the governor is again regulated, and gives the same speed in the altered cir- cumstances. It is easy to arrange that a large amount of regulating power shall be implied in a single turn of the nut-collar relatively to the central shaft, and yet that the periodic application and removal of about ;\, of this amount in the half- period of the pendulum shall cause but a very small periodic variation in the speed. The latter important condition is secured by the great moment of inertia of the governing masses themselyes round the main shaft. My communication to the Royal Society ended as follows :— “T hope after a few months trial to be able to present a satisfactory report of the performance of the clock now completed according to the principles explained above. As many of the details of execution may become modified after practical trial, it is unnecessary that I should describe them minutely at present. Its general appearance, and the arrangement of its characteristic parts, may be understood from the photograph now laid before the Society.” T am sorry to say that the hope here expressed has not hitherto been realized. Year after year passed producing only more or less of radical reform in various me- chanical details of the governor and of the fine movement, until about six months ago, when, for the first time, I had all except the pendulums in approximately satisfactory condition. By that time I had discovered that my choice of zinc and platinum for the temperature compensation and lead for the weight of the pendu- lums was a mistake. I had fallen into it about ten years ago through being in- formed that in Russia the gridiron pendulum had been reverted to because of the difficulty of getting equality of temperature throughout the length of the pendu- lum; and without stopping to perceive that the right way to deal with this diffi- culty was to face it and take means of securing practical equality of temperature throughout the length of the pendulum (which it is obvious may be done by simple enough appliances), I devised a pendulum in which the compensation is produced by a stiff tube of zinc and a platinum wire placed nearly parallel each to the other throughout the length of the pendulum; and the two pendulums of the clock shown to the British Association were constructed on this plan. Now it is clear 52 REPORT—1876. that the materials chosen for compensation should, of all those not otherwise ob- jectionable, be those of greatest and of least expansibility. Therefore, certainly, glass or platinum ought to be one of the materials; and the steel of the ordinary astronomical mercury pendulum is a mistake. Mercury ought to be the other (its cubic expansion being six times the linear expansion of zinc), unless the capillary uncertainty of the mercury surface lead to irregular changes in the rate of the pen- dulum. The weight of the pendulum ought to be of material of the greatest spe- cific gravity attainable, at all events unless the whole is to be mounted in an air- tight case, because one of the chief errors of the best existing pendulums is that depending on the variations of barometric pressure. The expense of platinum puts it out of the question for the weight of the pendulum, even although the use of mercury for the temperature compensation did not also give mercury for the weight. Thus even though as good compensation could be got by zinc and platinum as by any other means, mercury ought, on account of its superior specific gravity, to be preferred to lead for the weight of the pendulum. I have accordingly now made several pendulums (for tide-gauges) with no other material in the moving part than glass and mercury, with rounded Imife-edges of agate for the fixed support; and I am on the point of making four more for two new clocks which I am haying made on the plan which forms the subject of this communication. I have had no opportunity hitherto of testing the performance of any of these pendulums; but their action seems very promising of good results, and the only untoward circumstance which has hitherto appeared in connexion with them has been breakages of the glass in two attempts to have one carried safely to Genoa for a tide-gauge made by Mr. White to an order for the Italia Government. . As to the accuracy of my new clock, it is enough to look at the pendulum vi- brating with perfect steadiness, from month to month, through a range of half a centimetre on each side of its middle position, with its pallets only touched during 3} Of the time by the escapement-tooth, to feel certain that, if the best ordinary astronomical clock owes any of its irregularities to variations of range of its pen- dulum, or to impulses and friction of its escapement-wheel, the new clock must, when tried with an equally good pendulum, prove more regular. I hope soon to have it tried with a better pendulum than that of any astronomical clock hitherto made; and if it then shows irregularities amounting to =; of those of the best as- tronomical clocks, the next step must be to inclose it in an air-tight case kept at constant temperature, day and night, summer and winter. On Mr, Sabine’s Method of Measuring small Intervals of Time. By W. H, Watenn, On Tidal Operations in the Gulf of Cutch by the Great Trigonometrical Survey of India. By Capt. A. W. Barro, 2.2. The primary object of the operations was to determine whether secular changes in the level of the land at the head of the Gulf, ze. the “Runn of Cutch,” are taking place. Col. Walker, the Superintendent of the Great Trigonometrical Survey of India, at first intended to restrict the observations to a few weeks duration; but he found that by extending them to a period of a little over a year, scientific re- sults of the highest value would be obtained, and also that this course would be necessary in order to obtain data sufficient to detect minute changes in the relative level of land and sea, Iwas deputed when in England in 1871 to study the details of tidal observations and harmonic analysis as recommended by the British Asso- ciation; at the same time I tested a new self-registering tide-gauge, the per- formances of which were very satisfactory. The self-registering tide-gauges were then described at length, the most remarkable feature in them being the unusually a TRANSACTIONS OF THE SECTIONS. 53 long barrels (length 5 feet), which were provided in order to give the tidal curves on the diagram on a very large scale. Six of these instruments had been sent out to India some years before; they were modified in Bombay, so as to be similar to the new one which was tested at Chatham, and had scales of wheels put on for adaptation to particular tides, friction-rollers for the barrel, zero-lines for time and height cut, &c. As the rise and fall of the tide is materially infiuenced by direction and force of the wind, and also by changes in the barometer, self-registering anemo- meters and barometers were procured for each tidal station. On my return to India I was ordered to make a reconnaissance of the Gulf of Cutch, to select sites for tidal stations. I cruised about for a month in a common native sailing-boat, and after long searching along the muddy foreshores of the Gulf I found three places well adapted for tidal observations—one right at the head of the Gulf, just in the Runn of Cutch, called Haustal Tidal Station; another midway up the Gulf of the Cutch coast, called Nowanar; and the third, Okha, just at the mouth of the Gulf, opposite the island of Beyt. They were well situated for the purposes required, as far as their geographical position; but as one was ata point twenty miles from the nearest village (from which drinking-water had to be trout by boat as well as food for the men in charge), another station nine miles, and the third two miles from the villages, the arrangements for the continuous working of the stations for about a year and a half had to be most carefully made. I returned to Bombay and got all the apparatus ready, such as iron cylinders in length (so as to be portable), iron piping, suction-piping, anchors, and buoys, &c. for the deep-sea connexion, temporary tide-gauges for comparison, portable observatories—in fact every thing, even to bricks and lime for sinking the masonry well for holding the cylinders, for nothing could be procured in the places selected for the stations. While in Bom- bay I tested the working of the whole apparatus for each observatory, and made many modifications from time to time. I found that air would collect in the pipes, which were in the shape of a long siphon, and thus cause differences of level in the cylinder and the sea. I overcame this difficulty by inserting stopcocks at the top bends, which were to be always below the lowest high-water; and in this way I was able to get the same level of the water inside the cylinder as in the open sea. By frequent comparison with the temporary tide-gauges, the identity of level was determined ; the size of the pipe connecting the cylinder had been calculated, so that practically there would be no retardation in the flow of the water. The native sub-suryeyors, who were to be in charge of the stations, were also trained in Bombay. The observations and apparatus were then described at length, and several illus- trations and diagrams showed the method of their working. In addition to the self-registering anemometer and self-registering aneroid barometer, each observatory was fitted out with a standard mercurial barometer (for comparisons) and a rain- gauge. Three bench mark-stones in masonry platforms, at different distances from the observatory, were built as standard points for the levels, and each carefully connected with the zero of the self-registering tide-gauge. The whole of the appa- ratus and instruments were sent off in a large native sailing-vessel direct to Okha, the natives who were to be employed also going. I marched across Kattyanon to Okha, having made some arrangements with the Political Agent at Rajkot as to the help we should get from the native states. The construction of Okha tidal station was then described, and many of the difficulties which were successfully overcome ; also the different methods of comparing position of pencil on diagram with the height of water ; checks on the working of the instruments for insertion in the daily reports submitted by the sub-surveyors. I detected a serious fault in the self- registering tide-gauge, viz. that the instrument was by no means correct in the time registration. 1 eventually devised a simple, plan which I called “back-lash weight,” which completely removed this cause of error: I am of opinion this plan ‘ought to be carried out in its entirety, and the barrel made to drive the clock in- stead of the clock the barrel. Just after all was ready, and the instruments being started at Okha, a great dis- aster happened early one morning. A boat drifted down past the station, her anchor dragged across the flexible pipe, smashed it, and carried off a large portion of it, as well as buoys, anchor, &e, Mere we had to land and to haye the repairs quickly 54 REPORT—1876. executed; then the final measurements for determination of zero, rating of clocks, &c. were made, and the instrments started on their eighteen months’ work. Leaving Okha, the vessel in which I and my men and all the apparatus were in ran straight on to a sandbank and nearly capsized. After many troubles, the other two stations were eventually constructed. Huts had to be made for the men in charge and the guard from the native state to live in, a regular service for sending food and water established, and post-runners started to carry the daily reports to the nearest post-office, and many other details arranged. I or my European as- sistant had to make frequent tours of inspection of the stations while work was going on, which entailed much hard marching and exposure. One journey (in May 1874) was described in which I and my assistant had to ride on camels over about fourteen miles of the Runn, covered with water from 6 inches to a foot deep, in order to reach Haustal Tidal Station. The working of the stations was then de- scribed, Okha and Haustal giving perfect and continuous registration; but at Nowanar, where there was 20 feet of water at the end of the pipe at low-water in April 1874, in the following July it silted up and buried the pipe, and the whole configuration of the foreshore altered. New pipes had to be got up, and two lunations (from March to May 1875) were secured, in addition to the one and half lunation got before the shore had altered, in 1874. The registrations of the ane- mograph and barograph were continuous also. The levelling operations (750 miles of double levelling were done in connexion with the work) were next noticed ; the rigid method of procedure which obtains in the Great Trigonometrical Survey of India, and which give such wonderfully accurate results, was referred to (vide Col. Walker’s paper in vol. xxxiii. of the Memoirs of the Astron. Society). The reductions of the tidal observations are in progress, some idea of the magni- tude of which may be imagined when 30,000 points have been corrected to true mean local time on the diagram-sheets, corrections made for zero error, and then the 30,000 final measurements made and tabulated for reduction. The determina- tion of the mean level of the sea at each station and some of the results already deduced are stated: one is important, and that is, that the mean level deduced from the two months (March 7 to May 7) is nearly identical with the mean of the whole ear; and this Col. Walker had predicted would be the case in a letter on the subject about eight years before. The meteorological reductions are in progress. The movement of the wind for each hour for the whole period has been tabulated and reduced to its N. and E. components, the mean hourly value determined ; and, by combining the differences of this mean from the value of each particular hour, and similarly the barometric differences with the differences of the theoretical and actual values of the tide, I hope to determine far more accurately than has yet been done the effect of the wind and barometer on the tide. Several tracings of the actual diagrams were exhibited. The tidal curves are most regular and con-. tinuous, and show the perfect working of the whole apparatus ; and when the tidal and meteorological reductions are complete, I hope to obtain some very valuable results. Physical Explanation of the Mackerel Sky. By Sir W. Tuomson, D.C.L., F.BS. On Navigational Deep-sea Soundings in a Ship moving at High Speed. By Sir W. Tuomson, D.C.L., F.R.S. CO Ee a ST TRANSACTIONS OF THE SECTIONS. 55 CHEMISTRY. Address by Wiit1am Henry Perrin, F.R.S., President of the Section. THERE can be no doubt that chemistry and the allied sciences are now being re- cognized to a much greater extent in this country than in former years; and not only so, the workers at research, though still small in number, are more numerous than they were. In 1868 Dr. Frankland, in his Address to this Section at the Meeting at Norwich, commented upon the small amount of original research then being carried on in the United Kingdom ; but, judging from the statistics of the Chemical Society, this state of things became even worse; for in 1868 there were forty-eight papers read before the Society, but in 1872 only twenty-two. Since then, however, there has been a considerable increase in the number; and at the Anniversary Meeting in March last it was shown that the number of communications for the session had risen to sixty-six, or three times as many as in 1872. Of course these figures only refer to the Chemical Society; but I think they may be taken as a very safe criterion of the improved state of things, though it would be very gratifying to see much greater activity. It is also very pleasing to find that the aids to and opportunities for research are increasing, because it must be remembered that, in a pecuniary sense, science is far from being its own rewarder at the time its truths are being studied, although the results very often become eventually of the greatest practical value ; hence the wisdom of a country encouraging scientific research. But little, however, has been done in this direction in past years—the grants made for general science by this Association, and that of the Government of one thousand pounds annually to the Royal Society, being the most important. The Chemical Society has also been in the habit of giving small grants for the purpose of assisting those engaged in chemical research. In the future, however, it will be able to do much more than hitherto. One of the original members of the Society, Dr. Longstaff, offered inthe early part of the year to give one thousand pounds rovided a similar sum could be raised, the united amount to be invested and the interest applied for the encouragement of research. Iam happy to say that rather more than the required sum has been raised, and it is tanec that it may be still further supplemented. In addition to the Royal-Society grant, the Government have given this year a further annual sum of four thousand pounds. Of course this is for science gene- rally. Mr. T. J. Phillips Jodrell has also placed at the disposal of the Royal Society the munificent sum of six thousand pounds to be applied in any manner that they may consider for the time being most conducive to the encouragement of research in Physical sciences. When we consider how much of our science is of a physical nature, we must be grateful for this bequest; and it is to be hoped that these helps will more and more stimulate research in the United Kingdom ; and if we have any hope of keeping pace with the large amount of work now being carried on in other countries, we must indeed be energetic. The employment of well-trained chemists in chemical works is now becoming much more general than heretofore, especially on the continent, where in some cases a considerable staff is employed and provided with suitable appliances, &c., for the purpose not only of attending to and perfecting the ordinary operations which are in use, but to make investigations in relation to the class of manufacture they are engaged in. A conviction of the necessity of this is gaining strength in this country, though not so quickly as might be desired ; nevertheless these things are encouraging. With reference to the progress of chemistry and what have been the fruits of re- search of late years, it will be impossible for me to give eyen a general outline, the amount of work being so large ; in fact, to recount the list of investigations made during the past year would take up most of the time at my disposal. 56 REPORT—1876. Amongst the most interesting, perhaps, are those relating to isomerism, especially in the aromatic series of organic bodies; and it is probable that a more intimate knowledge of this subject will be found of really practical value. As I am unable to give an account of the work done during the past year on account of its quantity and diversity, I propose to refer to some of the practical results which have already accrued from Organic Chemistry, as a plea for the encourage- ment of research; and those I intend to speak of are of special interest also on account of their close connexion with the textile manufactures of Great Britain. I need scarcely say I refer to the colouring-matters which have been obtained from the products found in tar. It was in 1856, now twenty years since, that this industry was commenced by the discovery of the “mauve” or ‘aniline purple ;” and it may be of interest to state that it was in Scotland, in the autumn of the same Year, that the first experi- ments upon the application of this dye to the arts of dyeing and calico-printing were made, at Perth and Maryhill. I need scarcely remind you of the wonderful development of this industry since then, seeing we now have from the same source colouring-matters capable of pro- ducing not only all the colours of the rainbow, but their combinations. I wish, however, to briefly refer to the date and origin of the products which haye served to build up this great industry. It was in 1825 that Faraday published in the ‘ Philosophical Transactions’ his research on the oily products separated in compressing oil-gas, and described a substance he obtained from it—a volatile colourless oil, which he called Bicar- buretted Hydrogen. Mitscherlich some years afterwards obtained the same sub- stance from benzoic acid, and gave it the name it bears, viz. “ Benzol.” This same chemist further obtained from benzol nitrobenzol, by acting upon it with nitric acid. Zinin afterwards studied the action of reducing agents upon nitrobenzol, and obtained “aniline,” which he at that time called Benzidam. Again, Pelletier and Walter discovered the hydrocarbon toluol in 1837. Deyille produced its nitro-compound in 1841 ; and Hofmann and Muspratt obtained from this ‘‘toluidine,” by the process used by Zinin to reduce nitrobenzol. I might mention other namesin connexion with these substances, such as Runge and Unyerdorben ; but I would now ask, did any of these chemists make these investigations with the hope of gain? was it not rather from the love of research, and that alone? and now these products, which were then practically useless, are the basis of the aniline colours. But to go further: Doebereiner a long while ago obtained from alcohol a substance which he called “light oxygen ether,” now Imown as aldehyd. Gay-Lussac produced iodide of ethyl in 1815. Dumas and Peligot discovered the corresponding substance iodide of methyl in 1835; but, as in the cases I have previously referred to, these bodies had no practical value and were never prepared but in the laboratory. Hofmann, in his researches on the molecular constitution of the volatile organic bases, discovered in 1850 the replacement compounds of aniline containing alcohol radicals. All these compounds have now been manufactured on the large scale and used in the further development of the industry of these artificial colouring-matters. Other substances might be mentioned ; but I think these are sufficient to show how the products of research which, when first discovered and for a long period afterwards, were of only scientific interest, at last became of great practical value; and it is evident that, had not the investigations and discoveries I sie referred to been made as they were solely from a love of science, no aniline colours would now be known. The colouring-matters I have hitherto spoken of are nitrogenous, and derived from benzol and its homologues. There are a few others, however, of the same origin which contain no nitrogen; but they are of secondary importance. I now pass on to another class of colouring-matter, which is obtained from anthracene, a coal-tar product differing from benzol and toluol in physical cha- racters, inasmuch as it is a magnificent crystalline solid. The first colouring-matter derived from anthracene which I wish to draw your attention to is alizarin, the principal dyeing agent found in madder-root. This substance was for a long time supposed to be related to naphthaline, inasmuch as TRANSACTIONS OF THE SECTIONS, 57 phthalic acid can be produced from both of them ; and many were the experiments made by chemists in this direction ; it was not, however, until 1868 that this was proved to bea mistake, and its relationship to anthracene was discovered by Graebe and Liebermann, who succeeded in preparing this coal-tar product from the natural alizarin itself. Having obtained this important result, they turned their attention further to the subject, hoping to find some process by which alizarin could be produced from anthracene ; in this they were soon successful. The discovery of the artificial formation of alizarin was of great interest, inas- much as it was another of those instances which have of late years become so numerous, namely the formation of a vegetable product artificially ; but the process used by Graebe and Liebermann was of little practical value, because too expensive for practical purposes. aving previcusly worked on anthracene derivatives, it occurred to me to make some experiments on this subject, which resulted in the discovery of a process by which the colouring-matter could be economically produced on the large scale: Messrs. Caro, Graebe, and Liebermann about the same time obtained similar results in Germany; this was in 1869, Further investigation during that year yielded me a new process, by which “ dichloranthracene” could be used in place of the more costly product anthraquinone, which was required by the original processes. I mention this, as most of the artificial alizarin used in this country up to the end of 1873, and a good deal since, has been prepared by this new process, It was observed that when commercial artificial alizarin prepared from anthra- quinone, but more especially from dichloranthracene, was used for dyeing, the colours produced differed from those dyed with madder or pure alizarin ; and many ersons therefore concluded that the artificial colouring-matter was not alizarin at all. his question, however, was setat rest by separating out the pure artificial alizarin from the commercial product and comparing it with the natural alizarin, when it was found to produce exactly the same colours on mordanted fabrics, to have the same composition, to give the same reactions with reagents, and to yield the same products on oxidation. But whilst examining into this subject it was found thata second colouring-matter was present in the commercial product, and in somewhat large quantities, especially when dichloranthracene had been employed in its preparation; and to this was due the difference in shade of colour referred to. This substance, when investigated, was found to have the same composition as “surpurin,”’ also a colouring-matter found in madder, but of very little value on account of the looseness and dulness of some of the colours it produces. This new substance, being derived from anthracene, was named anthrapurpurin; unlike its isomer purpurin, however, it is of great value as a colouring-maiter. Ido not think I shall be going beyond the results of experience if I say it is of as great importance as alizarin itself; with alumina mordants it produces reds of a more scarlet or fiery red than those from alizarin. In fact so fine are the colours produced that, with ordinary alumina-mordants on unoiled cotton, it gives results nearly equal in brilliancy to Turkey-red produced with madder or garancine; and I believe the rapid success of artificial alizarin was greatly due to its presence. Most of that consumed at first was for ‘Turkey-red dyeing ; and the colours were so clear that it was mostly used in combination with madder or garancine, to brighten up the colours produced by these natural products. The purple colours anthrapurpurin produces with iron mordants are bluer in shade than those of alizarin, and the blacks are very intense. Its application is practically the same as alizarin, so that they can be used in combination. As already noticed, the commercial product called “artificial alizarin”’ first supplied to the consumer was always a mixture of alizarin and anthrapurpurin ; and various mixtures of these two colouring-matters are still sent into the market ; but, owing io the investigations that have been made and the study and attention that has been given to it by manufacturers, nearly pure alizarin and anthrapurpurin ave also sent into the market—the first being known as “ blue-shade alizarin,” and the second as red or “ scarlet alizarin.” 1876. 5 58 REPORT—1876. The formation of anthrapurpurin in the manufacture of alizarin may to some extent be said to have arisen from a want of knowledge of the true conditions required for the production of the latter. It is now well known that alizarin is a dioxyanthraquinone, or, in other words, anthraquinone in which two atoms of hydrogen are replaced by hydroxyl. C,, H, 0, C,, H, (HO), 0, Cy-- ——,,-— Anthraquinone. Alizarin. If we want to introduce hydroxyl into a compound, there are several processes which can be used; but I will only refer to those connected with the history of this colouring-matter. The first process which I will refer to has been used by chemists for a long period. It consists in first replacing the hydrogen by bromine, and then treating the resulting body with potassic or other metallic hydrate ; and according as one, two, or more atums of hydrogen have been replaced by the bromine, so on its removal by the metal of the metallic hydrate, a compound containing a corre- sponding number of atoms of hydrogen replaced by hydroxyl is obtained. Graebe and Liebermann acted upon this principle in their experiments on the artificial formation of alizarin; and as it was necessary to replace two atoms of hydrogen in anthraquinone, they first of all prepared a dibrominated derivative, called dibromanthraquinone, OF Ebr Os By decomposing this with potassic hydrate at a high temperature, they obtained a violet-coloured product, which, when acidified to remove the alkali, gave a yellow precipitate of alizarin, C,, H; (HO), O,. The second process I wish to speak of for the replacement of hydrogen by hydroxyl in a compound is by converting it into a sulpho-acid (usually by means of sulphuric acid), and subsequently decomposing this with potassic or other hydrate; and according as a mono- or disulpho-acid is employed, it yields on decomposition a compound with one or two atoms of hydrogen replaced by hydroxyl. The discovery of sulpho-acids of anthraquinone, and their use in place of the brominated derivative originally employed by Graebe and Liebermann, constituted the great improvement in the manufacture of alizarin already referred to. From what has just been stated, it was naturally supposed that a disulpho- acid of anthraquinone would be required to produce alizarin; and this was believed to be the case for some time; but further experiments have proved it to be a mistake, and shown that the monosulpho-acid is required to produce alizarin, the - disulpho-acid yielding anthrapurpurin. But how are we to explain this apparent anomaly ? It would take up too much time to enter into a discussion respecting the constitution of the sulpho-acids of anthraquinone in reference to the position of the HSO, groups. I will therefore confine my remarks to their decomposition. Monosulphoanthraquinonic acid, C,, H, (HS80,) O,, when heated strongly with caustic alkali, as potassic or sodie hydrate, decomposes in the ordinary way, and we get ‘ monoxyanthraquinone,”’ C,, IZ, (HO) 0,, which is a yellow body possessing no dyeing properties, On further treating this, however, with caustic alkali it changes, being oxidized, and yields alizarin, Cy H, (HO), O.. Disulphoanthraquinonic acid, C,H, (HS0,) 0, when subjected to the influence of caustic alkali, at first changes into an intermediate acid, C,,H, (HO) (HSO,) 0,, TRANSACTIONS OF THE SECTIONS. 59 and then into a dioxyanthraquinone, C7, ty, 10}, G, now known as “ isoanthraflavic acid’””—a substance having the same composition as alizarin, but being only an isomer of that body and possessing no affinity for mordants; like monoxyanthraquinone, however, when further heated with alkali it becomes oxidized and yields a colouring-matter, which is “ anthrapurpurin,”’ C,, H; G10), O,. Looking at these reactions, it appears rather remarkable that Graebe and Liebermann should have succeeded in preparing alizarin from dibromanthraquinone, It can only be explained on the assumption that the hydrogen atoms replaced in the disulpho-acidare different in position from those replaced in the dibromanthraquinone; and of course it is possible that a disulpho-acid isomeric with that now known may be discovered that will yield alizarin as a first product on treatment with alkali. In the reaction which takes place when monoxyanthraquinone or isoanthraflavic acid become oxidized and change into alizarin and anthrapurpurin nascent hydrogen is formed ; and this causes a reverse action to take place—ordinary anthraquinone, or its hydrogen derivative, being formed, and a loss of colouring-matter resulting. A small amount of potassic chlorate is now used with the caustic alkali, just suffi- cient to overcome the reducing action, which has resulted in an increased yield of colouring-matter, the percentage obtained being now not very much below the theoretical quantity. When the process for making commercial artificial alizarin by treating anthra- quinone with sulphuric acid was first adopted, the product from that treatment was a mixture of the mono- and disulpho-acids of anthraquinone. Consequently the colouring-matter prepared in this manner was a mixture of alizarin and anthrapur- purin; and the reason why dichloranthracene, when used in place of anthraquinone, yields a product very rich in anthrapurpurin, is on account of the readiness with which it forms a disulpho-acid of dichloranthracene, which afterwards changes into the disulpho-acid of anthraquinone. At first it was supposed by many that the quantity of coal-tar produced would not yield a sutticient supply of anthracene for the manufacture of artificial alizarin. Experience has, however, proved that this supposition was groundless, as now the supply is greater than the demand. oreover some very interesting experiments have lately been made, by which anthraquinoue and its derivatives have been obtained without the use of anthracene. The most interesting are those in which phthalic anhydride is employed with benzolic derivatives; for example, this anhydride gives with hydroquinone a colouring-matter having the same composition, as well as most of the other Beperties of alizarin. It iscalled quinizarin. Baeyer and Caro have also obtained rom phthalic anhydride and phenol oxyanthraquinone; and by using pyrocatechin in place of phenol they got alizarin itself. Although these products have not been obtained in sufficient quantities by these processes to be of any practical value, we do not know what further research may do. Already one of the substances used is being prepared on the large scale for the manufacture of that beautiful colouring-matter “ eosine ;” I refer to phthalic anhydride. Now, with reference to the origin of the products which are used for the manu- facture of artificial alizarin, we find the first researches made in reference to anthracene were by Dumas and Laurent in 1832; subsequently Laurent further worked upon this subject, and obtained, by the oxidation of this hydrocarbon, a substance which he called anthracenuse; he also obtained dichloranthracene. Dr. Anderson also made an investigation on anthracene and its compounds in 1863, and assigned to it its correct formula; he reexamined its oxidation-product, which Laurent called anthracenuse, and named it oxyanthracene, the substance we now know as anthraquinone. All these substances were without any practical value until 1868; but we now find them of the greatest importance, and used daily in immense quantities. But to bring out more clearly the practical importance of these fruits of scientific 60 REPORT—1876. research, it will be well perhaps to see what has been their influence on the colour- ing-matters which were in use before them, and also the extent of their present consumption. The influence of the so-called aniline colours on dye woods, &c. has been remarkably small. It is true that at first magenta had a depreciating infiuence upon cochineal ; but this has passed away, and now the consumption of that dye is as great as ever; certainly its price is much lower than it used to be; but this is due to a variety of causes, especially the great increase in the cultivation of the insect at Teneriffe. And perhaps this want of influence is not so very remarkable, when we consider the aniline colours are entirely new products, differing in com- position and properties from the old colouring-matters, and therefore could only displace them to a certain extent. But whilst this is the case, the aniline colours have been more and more used, until at present it is computed that their annual sale in the United Kingdom and on the Continent exceeds £2,000,000. This is probably due to new applications and increase of trade. When, however, we come to consider the influence of the anthracene colours alizarin and anthrapurpurin, more generally known as “ artificial alizarin,” we find we have a very different tale to tell. Here, in the case of alizarin, we have a competition not between two colouring- matters, but the same from different sources—the old source being the madder- root, the new one coal-tar. And when we introduce the consideration of anthra- purpurin, which produces such magnificent reds, much brighter than alizarin or ordinary purpurin, we see we have not only a replacement but an improvement, so that these new colouring-matters throw the old ones into the shade. The pro- ducts being purer, the clearing processes for goods dyed with them are also necessarily easier and simpler. It will be interesting to examine into the statistics of the madder and garancin trade in a brief manner, to see what has been the influence of artificial alizarin on their consumption. The following figures are mostly calculated from the Board-of- Trade returns. During the ten years immediately preceding the introduction of artificial alizarin the average annual imports of madder into the United Kingdom were 15,292 tons, and of garancin 2278 tons. Estimating the value of the former at £2 2s. 6d., and the latter at £8 per ewt., which were about the average prices during that period, the annual value in round numbers was about one million sterling. The introduction of artificial alizarin, however, has so influenced the value of madder that its price is now less than one half; and thus a saving of over half a million sterling per annum has been effected to the manufacturers of the United Kingdom, one half of which may be put down to Glasgow. So much for its effect in reducing prices; but what has been its influence on the consumption of these dye*stufis ? Ihave already stated the average quantity of these substances imported per annum prior to the discovery of the artificial product, and will now compare it with the imports of last year and this. That for the present year of course will be an estimated quantity, and calculated from the returns for the first seven months. Average annual imports. 1859-1868, 1875. 1876. tons. tons. tons. MAG den octets 15,292 5014 3653 Garancin ...... 2,278 1293 813 These figures speak for themselves. The money value, which was formerly £1,000,000 per annum, is now, cal- culating from the estimated quantity for the year, only £138,105, say £140,000, taking garancin at £4 per cwt. and madder at £1 per cwt., prices slightly in excess of their present value. At the present prices the cultivation of madder-roots is unremunerative; and itis to be expected that madder-growing will soon be a thing of the past, thousands of acres of land being at the same time liberated for the growth of those products eas.» TRANSACTIONS OF THE SECTIONS. 61 we cannot produce artificially, and without which we cannot exist. The quantity of madder grown in all the madder-growing countries of the world prior to 1868 was estimated te be 70,000 tons per annum; and at the present time the artificial colour is manufactured to an extent equivalent to 50,000 tons, or more than two thirds of the quantity grown when its cultivation had reached its highest point. I might have referred to other subjects besides the coal-tar colours which have resulted from scientific research; but I know of no other of such interest and magnitude. From the brief history I have given, we see that the origin of these colouring-matters is entirely the fruit of many researches made quite independently by different chemists, who worked at them without any knowledge of their future importance; and on looking at the researches which have thus culminated in this industry, it is interesting to notice that many, if not most of them, were conducted for the purpose of elucidating some theoretical point. These facts certainly ought to be a great encouragement to chemists, and stimu- late them to greater activity. It would be very pleasing to see more work ema- nating from the chemical schools of the United Kingdom; and I think no student should consider his chemical curricalum finished until he has conducted an original research. The knowledge obtained by a general course of instruction is of course of very great value; but a good deal of it is carried on by rule. In research, how- ever, we have to depend upon the exercise of our judgment, and, in fact, of all our faculties ; and a student having conducted even one, under the guidance of an efficient director, will find that he has acquired an amount of experience and knowledge which will be of the greatest value to him afterwards. It is hoped these remarks will encourage young chemists to patiently and earnestly work at whatever subject they may alortabs knowing that their results, although sometimes apparently only of small interest, may contain the germ of something of great scientific or practical importance, or may, like a keystone in an arch, complete some subject which before was fragmentary and useless. On a Safe and Rapid Evaporating-pan. By ¥. H. 'T. Auta. In the course of various chemical manufactures there is sometimes met the diffi- culty of products and apparatus being injured or destroyed in the process of rapid evaporation by the salts settling to the bottom of the pan, and there becoming a solid mass. This pan is intended as an effort to overcome that difficulty. Besides attempting to compass the evaporation of the leys or other fluids safe from the danger of deposition upon the heating-surface, it also provides for the rapid evaporation of the fluids, with continuous action in the pan, and the ready removal of the solids when formed. ‘Io attain these several ends, the form to be de- scribed has been found necessary. The pan may be made of boiler-plate, and about 30 feet long, by 10 feet broad, and 9 feet high. The heating-surface is supplied by two flues of a V-shape carried through the fluid from one end of the pan to the other. The acutest angle of the V is downward, and within 2 feet of the bottom of the pan. This form of heat-source whilst raising the temperature to boiling- point and efiectually keeping it there, offers no ere for descending particles ; and consequently the salts on separating fall to the bottom of the pan and there accumulate. Now the apparatus is so arranged that the bottom slopes in one or more directions; the salts gather in the deepest parts, and suitable outlets that may be closed at pleasure being provided in the sides, they gravitate outwards into proper receptacles. Care must be taken that sufficient solids are left in to occupy the outlets, and the passage of fluids thereby prevented. The upper part of the V-sha ae flue is covered in its whole length and breadth by an air-chamber of iron fitted with pipes or other arrangement passing into the liquid, whereby the air heated from the waste heat of the flue is forced into the boiling liquid, and there materially increases the rapidity of the evaporation. _ For the purpose of utilizing any heat that may escape from the air-chamber a small pan occupies its upper surface. On this subsidiary pan the liquid may be boiled to nearly salting-point, and then allowed to flow into the salting-down pan, 1876, 6 62 REPORT—1876. the smaller one being replenished with weak liquor. A limited supply of air may be introduced into the second pan, and evaporation proceeds very rapidly. The liquor in the pans need never lose its level, because, as salts pass from below and steam from above continuously, it is continuously replaced by liquor flowing in ; the air-pipes may therefore be only two or three inches below the surface of the fluid. The pressure thus being not great, an ordinary fan will be sufficient to force the air through for evaporation. On Sewage Purification and Utilization. By J. Banks. On a new Voltaic Battery. By H. W. Brees. On the Action of Pentachloride of Phosphorus on Turpentine. By Prof. Crum Brown. Note on Anthracene-testing. By Jas. T. Brown. In the earlier days of anthracene manufacture, when it was obtained solely from the last runnings of oil, and when the distillation was stopped comparatively early for the double reason of saving the bottoms of the stills and producing a good marketable pitch, the principal solid impurities were naphthalene, phenanthrene, and paraffin, With samples of this description the method of testing by agitation, after washing with petroleum spirit, with a limited quantity of bisulphide of carbon gives approximate and practically useful results. When, however, the demand for anthracene increased, the tar-distillers found it more advantageous to carry on the distillation as far as possible, only stopping just before the point at which coking commenced. This method of working gives an entirely different variety of crude anthracene, viz. one in which the principal solid impurities haye higher boiling- points than anthracene. These bisulphide of carbon fails to remove; that test therefore, with these samples, ceases to give true indications of their commercial value. To correct this the anthrakinone test was introduced, and was, judging from the terms in which it was propesed, looked upon as applicable to a// commercial anthracenes. The appendix to the paper soon followed, and showed that experience had not confirmed those anticipations ; and now the kinone produced requires to be tested as to its purity, as the result is by no means definite. In applying the kinone test to commercial samples various minor difficulties occur, one of which is that damp samples of anthracene are apt to lose moisture during the time that is occu- pied in reducing them to a sufficient degree of fineness to allow the small quantity of 1 gramme to be a correct sample of the bulk; and another and more serious one is the uncertainty caused by the occasional occurrence of accidental impurities in the quantity weighed out. To remedy these defects and facilitate the testing, the author proposes the following modification :— Weigh out 50 grammes of the crude anthracene, and measure out 250 cubic centims. of petroleum spirit; triturate the anthracene in a mortar with a sufficient quantity of the spirit to form a thin cream, and pour it on a weighed filter (taking’ care at the same time to leave in the mortar any grit or sand which may be present) ; rinse on to the filter any anthracene which may be round the sides of the mortar, and employ the remainder of the spirit in washing the filter and its contents. Allow it to drain, then fold it carefully, press between bibulous paper, dry at about 60°-80° C., and weigh. Crush to a fine powder the contents of the filter, and from that quantity weigh out the gramme required for the kinone test; then proceed in the usual manner. In calculating the result allowance must of course be made for the diminution in weight caused by washing the crude sample with petroleum spirit. Pithe method proposed in the foregoing short note does not claim for itself theo- relica accuracy, but it claims the following advantages :—, TRANSAOTIONS OF THE SECTIONS. 63 Ist. It affords a ready method of detecting and separating extraneous matter, such as grit, sand, shreds of canvas, or splinters of wood, all of which are liable to oceur even in good anthracene. 2nd. The preliminary washing produces a dry powder of perfect uniformity, from which it is easy to weigh out a small quantity. 3rd. The preliminary washing removes, beside others, the greater part of two important impurities, one of which, viz. paraftin, defies the kinone test, and the other, viz. phenanthrene, is not, if present in large quantities, completely oxidized under a considerable time. 4th. By removing a large proportion of the impurity beforehand the oxidation proceeds more quietly, and the kinone obtained is more crystalline and freer from chromium compounds. On some Instruments used in the ‘ Challenger” By J. Y. BucHanan. On Ammonic Seleniocyanide, By Dr. Cameron. On a Gas-condensing Machine for the Liquefaction of Gases by combined cold and pressure, recently employed in the manufacture of Volatile Liquid Hy- drocarbons. By J. 8. Coreman, FCS. This paper gives a résumé of the author’s paper on the effects of pressure and cold upon the gaseous products of the distillation of shales, read to the Chemical Society, September 1875. It then enters into certain thermodynamical questions relating to the best method of obtaining cold from a compressed gas, so as to utilize the cold produced in ex- pansion, to supplement the effect produced by simple pressure. It then describes the engineering arrangements finally adopted for dealing with 250,000 feet of gas daily at the works of Messrs. Young & Co., on the principle of the drawing exhibited. The diagrams used were enlargements of the actual draw- ings of the machine as erected, and showed all the precautions found necessary in actual construction. The working of the machine, which gives, as a maximum, 2000 gallons per week, during the last three months was described, and samples of the product exhibited burning in Laidlaw’s air-gas apparatus. Experimental Researches on the Chemical Treatment of Town Excretion. By J. 8. Corzman, F.CS. On the Transformation of Chinoline into Aniline. By Prof. Duwar, F.R.S.E, On the Proximate Analysis of Coal-Gas—Remarks on Reboul’s Paper on Pyro-Tartaric Acid. By W. Dirrar. On an Apparatus for the Analysis of Impurities in the Atmosphere. By EK. M. Drxon. On Fire-Brick. By J. Dunnacute. On White-Lead. By A, Frreusson. 6* 64 REPORT—1876. On the Physiological Action of Pyro-, Meta-, and Ortho-phosphorie Acids. By Prof. Gamensr, F.R.S,. On the Influence of the Condition and Quantity of the Negative Element on the Action of the Copper-Zine Couple. By Professor Grapsronz, F.R.S, On Solid Water. By Prof. Gururir, F.R.S. On the Critical Point of Liquid Carbonic Acid in Minerals. By W. N. Harter. The History of Copper-extraction by the Wet Way. By Wit1am Henperson. In this paper the author related the history of the introduction of these processes and their establishment in this country and abroad; he described the various stages of the manufacture of Spanish cupreous pyrites by his processes ; he also described and illustrated by specimens the recent modifications introduced for improving the quality of the copper, and at the same time separating the small quantity of lead, silver, and gold always present in Spanish pyrites. On the Purification of the Clyde. By Col. Horr, V.C. On the Limited Oxidation of Terpenes.—Part IV.* By Cuaruus T. Kineznrr, FCS, In this part of his researches the author has more particularly inquired into the phenomena attendant upon the atmospheric oxidation of turpentine in the pre- sence of water.*: These phenomena may be stated as:— (a) Increase of the specific gravity of the oil as the oxidation proceeds. (6) Gradual increase in the amount of peroxide of hydrogen produced, or the rate at which it forms. (c) Gradual heightening of the boiling-point of the oil as it oxidizes. The oxidation, which takes place slowly at first, proceeds very actively aiter- wards, and the oil thus under treatment is capable of inducing fresh turpentine, which may be added to undergo oxidation at the same rate from the moment of contact. The oxidized oil evolves large quantities of oxygen on heating to near 160° C., and this oxygen is doubtless derived from camphoric peroxide. To the same sub- stance the author assumes to be due the camphoric acid and peroxide of hydrogen found in the aqueous solution that results from its decomposition with water. There are contained also in the watery solution obtained when turpentine is atmospherically oxidized in the presence of water, acetic acid, camphor, &e. Thus a solution obtained in one experiment upon several gallons of turpentine contained 323 grains of Pe of hydrogen and 3867 grains of camphoric and acetic acids. The amount of peroxide of hydrogen produced is simply limited by the amount of turpentine oxidized, and can be regulated at will. his aqueous solution the author has proved to possess most powerful characters as an antiseptic and disinfectant, and continued investigations have shown these characters to be possessed by the individual constituents of the solution, viz. cam- * Printed 7 extenso in Chem. News, vol. xxxiv. pp. 127 & 135, and in Pharm, Journ, Sept. 23, 1876. ~ TRANSACTIONS OF THE SECTIONS. 65 horic acid, peroxide of hydrogen, &c. In the last part of his research the author as resumed the thread of his researches previously published, and found that menthene (C,, H,,), whether derived from solid or liquid Japan camphor (by the action of ZnCl,), produces, on atmospheric oxidation, among other bodies peroxide of hydrogen, acetic and formic acids, &c. Now Wright (Journ. Chem. Soe. ser. 2, vol. xiy. p. 2) has obtained from menthene, by the action of bromine, cymene; and so the conclusion stated in the author’s previous papers that all hydrocarbons con- taining cymene as a proximate nucleus give peroxide of hydrogen on oxidation is confirmed. Wright has also failed to obtain eymene (C,, H,,) from clove terpene (C,; H.,), a eo in accordance with the author’s observations previously made to the same effect. The author has submitted the ethers also to atmospheric oxidation, and in this way results haye been obtained which are of the greatest interest and importance. Ethylic ether Ce i O absorbs oxygen even in the cold, but more readily in sun- 2 . . shine, and gives rise in the presence of water to peroxide of hydrogen, which may result from reactions represented by the following equations :— (1) CH 0+0 aye 0+H,0, 2 By C,H, 2-6 H C,H, 0 C,H, 0 @ oH 04+0,= 6H oF 0,-+H, 0, (3) CHO 0,42H, 0509977 0+ Ht O+H, 0, ; or (3) may be written thus :— CH,COO 4H HO _ CH, COOH HO CH,CO O HHO( ~ CH, COOH HO That is to say, the ether may, in the first place, become acetic ether and eliminate water ; secondly, the acetic ether may become anhydride, and the latter may be finally converted into peroxide. This peroxide, being unstable in the presence of water, splits up into acetic acid and peroxide of hydrogen. These results are confirmed by the fact that Brodie discovered acetic peroxide by acting on acetic anhydride with baric dioxide. These equations are, moreover, exactly parallel with those indicated by the author as representing the production of hydric peroxide from turpentine, and it is to their substantiation that his efforts in the future will be directed. Meanwhile he claims that they experimentally demonstrate clearly for the first time the existence of the radical hydroxyl in combination ; and, in short, the production of peroxide of hydrogen + the way described amounts to the isolation of hydroxyl in combination with itself. On two new Hydrocarbons from Turpentine. By A, C. Lerrs. On Soda Manufacture. By J. Macrear. On the possible Genesis of the Chemical Elements out of a Homogeneous Cosmic Gas or Common Vapour of Matter. By Dr. Macvicar, F.R.S.E. On Essential Oil of Sage-—Part I.* By M. M. Parrison Murr, .R.S.E. This oil has a yellow-brown colour, without any shade of green, a strong sage-like odour, and a hot burning taste, Its reaction is neutral. Sage-oil does not deposit * Published in the Year-book of Pharmacy, 1876, p. 560. 66 ‘ REPORT—1876. any solid matter nor resin after standing for some months exposed to air; neither does its reaction alter. The oil rapidly absorbs oxygen from air. It is most ener- getically acted upon by strong nitric acid, also by sulphuric acid, which appears to polymerize some of the constituents of the oi]. Hydrochloric acid gas produces one or perhaps two liquids, but no solid chlorhydrates ; these are scarcely, if at all, de- composed by prolonged agitatation with warm water. The specific gravity of sage- oil is 0-9339 at 14° C. After prolonged fractionation the oil splits up into ae main portions—two liquids, almost certainly terpenes, boiling respectively at 157° and at 167° C.; a liquid, probably containing oxygen, boiling at 198°-203°; and a solid camphor melting at 187° C. The terpenes both appear to contain cymene, as by treatment with sulphuric acid, the liquid being caretully kept cold, and distillation in steam, cymene is obtained. These terpenes yield brominated compounds, which split up, on distillation, intohydrobromic acid and cymene ; the brominated compound from the lower boiling terpene is much more stable, however, than that from the terpene of higher boiling-point. For the oxygenized liquid constituent of the oil the name of salviol is proposed. The terpenes both yield terephthalic acid on oxida- tion with weak chromic liquor. On the action of Dilute Saline Solutions upon Lead *. By M. M. Parrison Murr, /.RS.E, After generalizing former results the author describes experiments carried out under varying conditions, which seem to prove :— (1) That increase of surface of lead exposed is generally associated with increase of lead dissolved. This conclusion does not, however, invariably hold good ; the nature of the salt in solution, the time of action, &c. influence the action. (2) That exposure of large surfaces of liquid to the surrounding air very gene- rally causes an increase in the quantity of lead dissolved, this increase being most marked in the case of those salts (nitrates &c.) which enable water to exercise a notable solvent action upon lead, and after the expiry of lengthened periods of time. (3) That the solvent action of dilute saline solutions upon lead increases in an ever-increasing ratio with increase of time of action (longest period tried = 505 hours), except in the case of potassium carbonate solutions, where a point of maximum action appears to be reached after the expiry of about 340 hours. On certain Compounds of Bismutht. By M. M. Parrison Murr, F.R.S.E. In this paper the following salts of bismuth are described :— Bismuthous trichloride and tribromide: the action of hydrogen upon these salts is detailed. Attempts to prepare a chloride higher than Bi Cl,, which led to no ositive results, are described. -Ammonio-bismuthous tribromides, Bi Br, .3NH,, Bi Br, .2NH,, and 2Bi Br,.5NH, ; bismuthyl oxybromides, Bi, Br, O,, and Bi,, Br, O,,3; bismuthie bromo-nitride, BiN, Br; hypobismuthie hydrate, Bi,O,.H,0; and a number of chromates of bismuth, the principal of which are :—bismuthyl chromate, (Bi O), Cr O, ; bismuthyl dichromate, (BiO), Cr, O,; monohydrated bismuthyl dichro- mate, (BiO), Cr,O,.H,O; and monohydrated bismuthyl tetrachromate, (Bi O), Cry 13° a 3 On Relations among the Atomic Weights of the Elements. By J. A. R. Newranps. On the Alum Process in Sugar-refining. By J. A. R. Newranns. * Vide Proc. Manch. Lit. and Phil. Soc. 1876-77, pp. 1 & 142. t Journ. Chem. Soe. vol. i, 1876, p. 144, vol. ii. p. 12, and vol, i, 1877, p. 24. - ———— LS ee eee eee TRANSACTIONS OF THE SECTIONS. 67 On Sugar. By T. L. Parrerson. Note on some new Anthracene Compounds. By W. H. Perkin, F.R.S. A very dilute solution of anthracene in carbon disulphide, when cooled to 0° C. and treated with bromine, yields an addition product, a“ dibromide of anthracene,” C,,H,, Br, It is a very unstable body, rapidly decomposing at the ordinary tem- perature of the air, with evolution of hydrobromic acid ; when heated it also gives off this acid, and is converted into monobromanthracene, C,, H, Br. If chlorine be used in place of bromine, a “dichloride of anthracene,” C,, H,, Cl, is produced, which is even less stable than the corresponding dibromide; when heated it decomposes and yields monochloranthracene, C,, H, Cl. On Picoline and its Derwatives*. By Witttam Ramsay, PA.D. i] ’ The following salts of picoline were prepared :— The hydrochloride, deliquescent, melting at 160° C. The hydrobromide, melting at 187°. These two salts may be crystallized from impure picoline. he dibromide of picoline hydrobromide.—Prepared by treating the hydrobromide with bromine. It forms golden-yellow scales, and melts at 85°. It is sparingly soluble in water. The ditodide of picoline hydriodide—Formed when picoline hydriodide is distilled. Reddish-brown crystals, which melt when brought in contact with water; soluble in alcohol and in ether. Melting-point 79°. The formula of Anderson’s trichloropicoline hydrochloride is disputed, both from the results of analysis, from its method of preparation, and from its properties. It appears to be a hypochlorite, and to-contain the group (O Cl). The white powder to which Anderson ascribes the formula C, H, Cl, N . Hic] is a product of the action of water on an oil obtained by projecting picoline into chlorine gas. Picoline dibromide, C,H, N. Br, formed by the action of a solution of bromine in chloroform on picoline, and Picoline iodochloride, C,H, N .CI1I, prepared in a similar manner, are crystalline solids. The halogens, therefore, act on picoline to form at least four distinct sub- stances :—1,a direct addition compound containing picoline plus two atoms of halo- gen; 2, a substitution compound which undergoes alteration when brought in con- tact with water; 3, a salt of the halogen acid; and 4, an addition-product con- taining two atoms of the halogen combined with the haloid salt. The ferrocyanide forms white crystals. The platinocyanide consists of barge pale yellow rhomboids. It crystallizes with 4H, O The tartrate forms long white needles. The citrate is uncrystallizable. The phosphate is a white deliquescent crystalline mass. The chlorate forms very thin diamond-shaped crystals. The following compounds with alcohol radicals were prepared :— The methyl iodide, by mixing equivalent quantities of methyl iodide and pico- line. Long white needles, which melt at 226°-5-227°. The methyl chloride is an extremely deliquescent salt, and crystallizes from alcohol in needles. The methyl nitrate forms large transparent prisms. The methyl hydrate, prepared by means of moist silver oxide, rapidly becomes discoloured in the air, and when acted on, first with bromine, then with ammonia, assumes a red colour. No methylamine was evolved on boiling its aqueous solu tion. The ditodide of the methyl iodide, C, H,N (CH,I) I,, erystallizes from alcohol in _ * Vide Phil. Mag. 1876, vol. ii. p. 269. 68 REPORT—1876. feathery bluish-black crystals. It is prepared by dissolving iodine in an alcoholic solution of the methyl iodide. The ethyl iodide is analogous to the methyl iodide ; and the ethyl hydrate gives a similar reaction with bromine and ammonia. The ethene bromide forms small hard prisms, which melt at about 276°. The ethene chloride crystallizes from alcohol in needles. Picoline allyl compounds are all sirups, with exception of the platino-chloride. The hydrate is more stable than the methyl, ethyl, or ethene hydrates, and after evaporation at 100° dissolves in aleohol with a brilliant purple colour, which may be communicated to silk. As picoline is not Pca by potash in any form, it cannot be a nitrile or a carbonine. It is not altered by being passed through a red-hot tube filled with lime or lead peroxide. Boiling sulphuric acid and nitric acid, or a mixture of both, have no action on picoline; but when the nitrate is heated it undergoes complete decomposition into carbonic acid and probably water. Picoline probably does not contain a methyl group; for on oxidation it yields Dewar’s pyridene dicarbonic acid. This acid is not derived from lutidine, as was supposed by Wright. Experiments to prepare the aldehyde and alcohol from dicarbo-pyridenic acid lead to a prospect of success ; and from the alcohol true methyl pyridine may possibly be obtained. On Glucinum, its Atomic Weight and Specific Heat. By J, Emerson Reynorps, M.D. On the Utilization of Sewage. By W. C. Star. On the Action of Hydriodic Acid on mixed Ethers of the General Formula CrHony1+0.CH;*. By R. D. Sirva. On Sodium. By AnpERsoN SMITH. On the Manufacture of Iodinet. By Enwarp C, C. Stanrorp, 7.0.8, The author gives an interesting account of this manufacture, which in Great Britain is confined to Glasgow and its neighbourhood. He gives a réswmé of the remarkable fluctuations in the price of iodine, and also of the changes in the uses of kelp, or sea-weed ash, from its first manufacture about a hundred years ago to the present time. He traces its use from the beginning of the present century, when it was the principal source of alkali, and when Scotland alone produced 20,000 tons annually, worth £20 to £22 per ton. During the following 22 years the importation of barilla reduced the price of kelp to £10 per ton. Then the rerio of the duty on barilla, followed by that on salt, reduced it further to £3 per ton, and in 1831 to even £2 per ton. In 1845 the manufacture of iodine com- menced, and kelp was again in demand. The imports and prices are shown in the following table (p. 69). It was impossible to give the imports of kelp earlier than 1845, as this table was obtained with difficulty from indirect sources, the Clyde trust having disposed of their books previous to 1859, thus rendering the early history of this interesting subject at present inaccessible for statistics. It is shown that a large number of makers of iodine in Glasgow at that time had been now reduced to three. * Vide Compt. Rend. lxxxi. pp. 323-325. t+ Published zn extenso in the ‘ Chemical News,’ 1877. ———————L—————— <= rl leer le wt TRANSACTIONS OF THE SECTIONS. 69 Kelp imports into Clyde, years ending June 30. Year......| 1866.| 1867. 1868.) 1869.) 1870. 1871. 1872. 1873. 1874. 1875. Tons of Kelp............ 8858)\8174'8116,8178| 9257 | 9384 | 10049} 9449 | 10923} 8643 Price of Iodine per lb.| 10/ | 12/ |12/8) 13/| 12/8 | 14/4 | 34/ | 24/8 | 15/8 | 10/8 Alverage |Kelp...| 9187 Pr. of \Iodine | 15/114 Y 1856.| 1857.) 1858,| 1859.) 1860. 1861. 1862, 1863. 1864, 1865. Tons of Kelp............ 6349/8641'8123'8190) 7754 | 9722 | 9414 | 14018 | 11349 | 13741 Price of Iodine per 1b.| 13/8) 12/4 10/6) 9/8 | 8/6 7/ 5/8 5/ 8/4 | 7/8 Average |Kelp...| 9730 Pr. of Iodine} 8/10 Year...... | 1846.) 1847.) 1848.) 1849.) 1850. 1851. 1852. 1853. 1854, 1855. Tons of Kelp............ '3627|4000/4400/4731| 11421 | 7320 | 5418 | 6491 | 4679 | 5826 Price of Iodine per lb.) 21/3, 11/| 11/|11/| 10/8 | 8/8 | 15/ | 15/4 | 12/ | 18/4 Alverage |Kelp...| 5811 Pr. of Iodine | 12/11 PYGAM en cea| ncsent||(sacnen| |ieerntasltaasesel Wanesccens 1841. 1842, 1843, 1844, 1845. Tons of Kelp............ ae acc|ssesae|nesesielveirnae|emareee. 2565 | 1887 | 1965 | 3268 | 6086 Price of Iodine per Ib,|...+06]......|...0..[.2..0+[oscoeeeee 5/ 4/8 6/ 12/ | 31/1 Average |Kelp...| 3133 Pr. of \Iodine | 11/9 The working of kelp for iodine is minutely described, with the remark that all the text-books on the subject describe only processes and apparatus abandoned by manufacturers many years ago. The large production of iodine which may be expected from the Chilian caliche is fully investigated and it is shown that the possible production far exceeds the utmost output of Great Britain and France ; but there are difficulties in the manufacture which have hitherto prevented very large imports from this source. he quantities of iodine in several species of sea-weed, and from a large num- ber of analyses of specimens from all parts of the coast, are tabulated. The author shows that all sea-weeds contain iodine; but few contain itin the quantity worth working. Thess are the deep-sea alge exclusively. His own researches are alluded to (Society of Arts, Silver Medal, Feb. 14, 1862) in reference to the great loss of iodine in the present wasteful method of burning kelp ; and his suggested improvement of collecting the winter tangle, now generally wasted, and distilling it in closed retorts, is described. The sea-weed is thus con- yerted into charcoal (which remains in the retorts), and ammoniacal liquor, and tar. condensed in suitable condensers, and gas, which is used to light the works, The gas liquor yields ammonia and acetic acid. From the charcoal, the salts of potassium and sodium, with iodides and bromides, are easily washed out, and a residual charcoal is obtained which resembles that:from bones. This charcoal is fully equal to animal charcoal as a decolorizer and deodorizer, and can be very cheaply obtained. The manufacture affords winter employment to a large and indigent population in the winter, when they most need it. It has been carried out on a large scale in some of the outward Hebrides, and has quadrupled the produce of iodine and greatly benefited the people. On Lead Desilverizing by the Zine Process. By J. KE. Sropparr. On the Atomicity of Oxygen and on the Constitution of Basic Salts. By J. JounstoneE Stoney, FBS, On Zine. By D. Swan, 1876. “I 70 REPORT—1876, On the Prevention of the Pollution of Rivers. By Rey. R. THomson. On the Growth of Mildew in Grey Cloth. By Wi1tt1am Tuomson, F.R.S.L. The author described the size used by Lancashire manufacturers, which is nearly always more or less strongly acid. Two series of experiments on the relative actions of salts, often added by manu- facturers to their size, in aiding or retarding the development of mildew, showed that the free acid present, together with dampness, is the most fruitful cause of mildew; and if the acid be neutralized with soda ash, mildew develops with much difficulty, and only after a very considerable lapse of time. On the Nitroso Derivatives of the Terpenes. By W. A. Trtpen, D.Sc. Preliminary Note on « new Iso-purpurine. By W. A. Titpen, D.Se. On the Prevention of Fraudulent Alterations in Cheques fe. By F. Waro. On the Means of Suppressing Alkali Waste: By WauteR Warton. New Cotarnine Derivatives. By C. R. Atper Wricuat, D.Sc. When dilute bromine water is added to a solution of cotarnine hydrobromide combination takes place, and a crystalline orange precipitate is thrown down con- sisting principally of dibrom-hydrocotarnine hydrobromide ; if excess of bromine be used, the precipitate chiefly consists of tribrom-hydrocotarnine hydrobromide, these two brominated bodies being formed thus :— Cotarnine. Dibrom-hydrocotarnine. C,, H,, NO,, H Br+Br,=C,, H,, Br, NO,, HBr. Tribrom-hydrocotarnine, C,, H,,Br, NO,, HBr+Br,=H Br+C,, H,, Br, NO,, HBr. If hydrocotarnine hydrobromide be used instead of cotarnine hydrobromide, and excess of bromine be added, the same tribrom-hydrocotarnine hydrobromide is formed, thus :— Hydrozotarnine. Tribrom-hydrocotarnine. C,,H,, NO,, HBr+3Br,=3H Br+C,, H,,Br,, NO,, HBr. Dibrom-hydrocotarnine hydrobromide loses the elements of hydrobromie acid, forming bromocotarnine hydrobromide on boiling with water, aqueous caustic potash, or alcoholic silver hydrate, thus :— C,, H,, Br, NO,, HBr=HBr+C,, H,, BrNO,, HBr. The bromocotarnine thus formed resembles cotarnine in many respects; its salts are crystallizable and very soluble ; the base when crystallized from ether is repre- sented by C,,H,Br NO., H,0, the associated water being lost at 100° with partial decomposition just as with cotarnine, When heated to about 180°, hydrobromic acid is evolved; the residue contains a blue product insoluble in boiling alcohol, ben- zene, chloroform, petroleum, turpentine, carbon disulphide, and ether, but sparingly soluble with a brilliant blue colour in boiling glacial acetic acid, glycerine, or amline, and readily soluble in cold concentrated sulphuric acid to a most intensely coloured magenta liquid: the colorific power of this body is most remarkable, a ~ minute speck scarcely visible giving a deep coloration to a considerable bulk of i i le cll TRANSACTIONS OF THE SECTIONS. 71 acid. As yet this body has not been obtained in sufficient quantity and sufficiently ae for analysis; the fact that concentrated warm sulphuric acid does not char it, ut only dissolves it, suggests some constitutional similarity to indigo. Tribrom-hydrocotarnine hydrobromide breaks up, on heating to 180-200°, in accordance with the reaction, C,,H,, Br, NO,, HBr=CH, Br+ HBr+C,, H, Br NO,, HBr, methyl bromide and hydrobromic acid being evolved and the hydrobromide of a new base being left. After due purification the free base is obtained from 80 per cent. alcohol in bright oange crystals containing C,, H, Br NO,, 2H,O, the water of crystallization being lost at 100° and a brilliant evimson anhydrous base being left. This crimson mass is a delicate test for the presence of moisture in nearly absolute alcohol; when crystallized from such containing only a minute trace of moisture, orange hydrated crystals are thrown down on cooling, whilst crimson anhydrous crystals are formed when very carefully dehydrated alcohol is employed: it may benoted that long standing over and distillation from a large bulk of quicklime does not sufficiently dehydrate ordinary 90 per cent. spirit to give crimson crystals " by this test. The salts of this base readily crystallize; the hydrochloride and hydrobromide are of a straw-yellow colour and sparingly soluble in cold water; on adding sodium carbonate to the warm only slightly yellow aqueous solution, bright orange crystals of the free base separate rapidly on stirring. The bromine in this base is apparently incapable of elimination by nascent hydro- gen; it is Popes to designate it bromotarconine, “ tarconine” (anagram of nar- cotine and of cotarnine) being the (as yet hypothetical) non-brominated base C,, H, NO,, differing from cotarnine (C,, H,, NO,) by the elements of marsh-gas, On the Alkaloids of the Aconites. By C. R. ArpER Wrieut, D.Sc. The results communicated to the Association last year, together with those obtained by Duquesnel, seem to point to the inference that when a mineral acid is used to acidify the alcohol used in the extraction of alkaloids from aconite roots, alteration of the base or bases originally present takes place to a greater or less extent, owing to the influence of the heat employed to evaporate the alcoholic extract ; whereas if tartaric acid be used, and the extract be evaporated at as low a temperature as possible, as in the experiments of Duquesne], much less alteration takes place and a considerable amount of a base crystallizable from ether is obtained. Two cwt. of Aconitum napellus were worked up by this latter process for the purpose of examining more closely the character of the crystals thus obtained ; the extract, evaporated gently to a small bulk, was treated with water and filtered from precipitated resin; the aqueous filtrate then yielded a semicrystalline precipitate when treated with potassium carbonate in slight excess. This precipitate was fractionally crystallized from ether and other solvents, and finally split up into a large number of fractions ; no evidence, however, could be obtained of the presence of more than one crystalline base ; all the fractions, when sufficiently purified from a small quantity of an obstinately adherent non-crystalline base of lower molecular weight, gave identical numbers agreeing with the formula C,, H,, NO,,, the gold salt being indicated by C,, H,, NO,, HCl, AuCl,. This crystallized base, to which it is proposed in future to restrict the term aconitine, is eminently active physiologically, and agrees closely in all its properties with the “ crystallized aconitine ” of Duquesnel obtained by the same process, the different formula arrived at by Duquesnel (viz. C,,H,,NO,,) being apparently due either to impurity in the substance examined or to analytical imperfections. The base, crystallizable from ether, obtained in small quantities from A. napellus _ by extraction with alcoholic hydrochloric acid, as described in the Brit. Assoc. Rep. 1875, p. 38, gave last year numbers from which the C,,H,;NO,,, or one closely similar, was deduced ; after further purification, however, this substance was found to be perfectly identical with the aconitine above described, giving numbers repre~ Sisied by C,, H,, NO,. 72 ; REPORT—1876. In order to purify aconitine completely from another base which does not crystal- lize from ether, but which obstinately adheres to aconitine when crystallized from that and other menstrua, it is sufficient to dissolve the approximately pure snow- white crystals already crystallized several times from ether in warm dilute hydro- bromic acid; on cooling and standing, well-defined crystals of the hydrobromide of aconitine separate, the other base being completely retained in the mother liquors ; the drained and washed crystals yield perfectly pure aconitine on dissolving in water, precipitating by sodium carbonate, and crystallizing the precipitate from ether. This non-crystalline base does not appear to form crystallizable salts; it has a considerably lower molecular weight than aconitine. Whether it is originally present in the roots, or is formed by alteration of the crystallizable aconitine during the extraction process, is not yet made out. These results, and those obtained last year, clearly point to the desirability of sub- stituting for medicinal purposes the uniform homogeneous crystallized base (or a salt thereof) for the more or less amorphous mixtures of aconitine and other sub- stances and alteration products usually found in pharmacy, inasmuch as some at least of these admixtures are considerably less physiologically potent than aconitine, CAEL NO: ‘ urther experiments on the constitution of aconitine and the amorphous base. or bases are in progress, GEOLOGY. Address by Professor J. Youne, M.D., F.G.S., President of the Section. WueEn the British Association met in Glasgow twenty-one years ago, Sir Roderick Murchison presided over Section C, and was surrounded by a brilliant company, whose names, now historical, were even then familiar for their accuracy of observa- tion, for philosophic generalization, and for the eloquence with which their science was clothed in words that charmed while they instructed—Lyell, Hugh Miller, Sedgwick, Jukes, Smith of Jordan Hill, Thomas Graham, Agassiz, Salter, Leonard Horner, John Phillips, Robert Chambers, H. D. Rogers, Charles Maclaren, Sir W. Logan: the list is a heavy one even for twenty-one years; and the changed cir- cumstances will be fully realized by Nicol, Harkness, Egerton, Darwin, Ramsay, and others when they find Murchison’s place occupied by one who holds it rather by the courtesy of the Council to the Institution in which we are assembled than by any claim he has to the honour. It would be out of place for me to do more than refer to the Geological advantages which have given to Glecasi its commercial greatness. In the Handbook prepared at the instance of the Local Committee will be found gathered together all the positive knowledge we possess regarding the mineralogy, stratigraphy, and palzon- tology of the west of Scotland. ‘The specimens themselves are exhibited in the Hunterian Museum and in the Corporation Galleries ; and I take it upon me to say the Glasgow geologists are as ready as ever to assist the investigations of students in special departments with all the material which richly fossiliferous strata yield and the careful skill of assiduous collectors can secure. Thus relieved from entering into local details, 1 would ask your attention for a short while to some of the difficulties which a teacher experiences in summarizing the principles of Geology for his students. I may be pardoned for reminding you that as yet there are in Scotland only two specially endowed teachers of Geology. In the Universities, that science for which Scotsmen had done so much received only the odd hours spared from Zoology. In 1867 the two courses were separated in Glasgow; in 1870 Sir R. I. Murchison founded the Chair of Geology in Edinburgh; in 1876 Mr. Honyman Gillespie endowed a Lectureship on Geology in Glasgow, not separating it from Zoology, but rather desiring the two to remain associated, while means were provided for tutorial instruction in the elementary work of the class. When next the Association meets mb) TRANSACTIONS OF THE SECTIONS. 73 in Glasgow, I hope that the services which science has rendered to mining and metallurgy may have been recognized by those who have reaped the benefit. During the efforts of years to obtain provision for systematic teaching in Mining and Metallurgy, practical and scientific have always been set in opposition by those whom I addressed. In another twenty years it may have become apparent that it is possible for a man to be both practical and scientific, and that the combination is most conducive to economy. Geology occupies the anomalous position of being a science without a special ter- minology, a position largely the result of its history, but to some extent inherent in its subject-matter. Treated of by Hutton and Playfair and their opponents in the ordinary language of conversation, current phrases Were adopted into science, not so much acquiring special meanings as adding new ambiguities to those already existing. Every one seemed to understand them at once; and thus, as no one was obliged to attach very precise meanings to them, the instruments of research became its impediments, and the phrases in common use at the beginning of the century have transmitted to the present day the erroneous ideas of those by whom they were first employed. When Lyell, in 1852, methodized the knowledge accumulated prior to that date, he had, in organizing the science, to choose between inventing an appropriate terminology and adopting that in common use. By doing the latter he promoted the popularity of the science, though at the cost of some subsequent confusion ; by attempting the former he would have set in arms against him those who would, according to the pedantry of the time, have denounced his neologisms and found in them a decorous veil for the objections which they entertained on other grounds to his views. Lyell was not the man to face the latter difficulty ; nor can it be charged against him that he was wittingly neglectful of the interests of science. But to the use of conversational language are traceable certain assump- tions to which I desire to draw your attention. In venturing criticism of this kind Tam not unmindful of the Nemesis which has overtaken my colleague, Sir W. Thomson for his comments on Lyell’s language. Thomson took exception to lan- guage which implied a kind of perpetual motion, a circulation of energy at variance with the teaching of physics: and, behold, two or three years after, Lockyer has published, as a physical astronomer, and Prestwich has approved, asa geologist, the opinion that the temperature of the sun may have fluctuated, that, in fact, changes of chemical combination may from time to time have refreshed the heat of the planet, whose uniform rate of cooling Sir William had assumed. - When stratigraphical geology first received due attention, the notion was pre- valent that each formation terminated suddenly by cataclysm ; it was therefore natural that the British succession, the earliest to be tabulated in detail, should be taken as a standard for other countries, and that the enumeration of the series should be a generalized section in which were incorporated those strata not pre- sent in Britain. The “ intercalation ” of beds thus practised to make an “incom- plete ” series “com lete,” still survives, as do the terms, though the notions which underlie them are formally denied by those who use them. A patriotic fellow- countryman once surprised us by his vehement denunciation of a treacherous Scot who called the Lanarkshire Limestones meagre and incomplete as compared with the English. With knowledge he might have made his criticism useful; as it was, he only gave a fresh example of the national peculiarity which, if it cannot prove Scotland to be better off than its neighbours, is content if it can make it out to beno worse. The abundant fossils of the Mesozoic strata of England and France ren- dered comparison easy, and created the impression that conchology was the A BC of geology, physical being subordinated to paleontological evidence. The balance has been somewhat restored by the Geological Survey, the precision of whose hysical observations enables them to guide the paleontologist as often as they ate to be guided by him. But one legacy from our predecessors we have not got rid of; nor, indeed, has its value been much called in question. The process of intercalation had at first to do only with observed gaps, into which obyious equivalents couid be received. But as the needs of speculative Biology rapidly increased, in the same ratio did belief in the imperfection of the geological yecord increase, till now we have that record described as a most fragmentary. yolume, nay, as the remains of the last volume, whose predecessors are lost to us, 1876. 74 REPORT—1876. Sir W. Thomson did good service by calling in question, on physical grounds, the indefinite extension backwards of geological time. The firstfruits of his crusade were the definitions of Uniformitarianism and Evolution which Prof. Huxley gave. Henceforth no one will maintain the onesided notions regarding these two opposing views of the earth’s history which were adopted in ignorant misconception or dic- tated by conceit and bigotry. But the service done was even greater; for while it became clear that a knowledge of physics was indispensable to him who would promulgate sound notions, it was further apparent that both biological and geolo- gical evolution had a limit in time, that in fact, on the assumption of the primitive incandescence of our globe, the date might be at least approximately fixed when the mechanical processes now at work commenced and when the surface of the earth became habitable. Nothing more has yet been done than to point out the way; for, though Prof. Guthrie Tait indicates a limit of from 15 to 10 millions of years, that statement can only be regarded as in effect, though not perhaps in in- tention, a protest against the liberality and vagueness of Sir W. Thomson’s allow- ance, which gave geologists a range of from one to two hundred millions of years. : The reconciliation of physicists and geologists is not likely to come through Mr. Lockyer’s researches, even if the earth’s history be shown to have been identical, unless the renewal of the earth’s heat be shown to be compatible with continued life on the surface. Ifthe reconciliation is looked for through the prolonged duration of the sun’s life, that being the gauge of the earth's duration, the expectation is still based on the supposed need of very great time for geological processes, or rather on the supposed need of very great time for biological evolution, to which geological evolution has been squared. There is another direction in which these results may help us to meet the limitation assigned by the physicists : the intervals of variation of temperature may be shorter than those which separate the maxima of eccentricity of the earth’s orbit; and thus the repeated cold periods of which we have suggestions in the stratified rocks, may have recurred within a shorter total period than is at present claimed. It is scarcely within the compass of this address to enter into the questions in- volved; but it is permissible to indicate the reason for delaying meanwhile accep- tance of any precise limit of time. There is as yet too much diversity of opinion as to the elements of the problem. Physicists are by no means at one as to the conditions which permit or prohibit shifting of the earth’s axis, Calculations are based on the assumption of the regularity of the earth’s form, under a certain con- stant relation of the masses, albeit of diverse specific gravity, which compose it. It is moreover assumed that the ratio of land and water have been uniform, though the formation of the grand features of the land by contraction of the cooling mass has not yet been considered as affecting this assumption by altering the disposition of the water. On the one hand it has been shown that the existence of uniform temperatures over the earth’s surface is a gratuitous hypothesis; on the other hand it is clear that the existing distribution of light and heat is incompatible with the flourishing of an abundant Carboniferous and Miocene flora within a short distance of the north pole. One expects that astronomers will look to the shifting of the axis of rotation as the possible explanation of the difficulty, taking into account likewise the shifting of the centre of gravity necessarily following those displacements of matter which, on the contraction theory, have determined the positions of the main continents and oceans. Mr. Evans, in his address to the Geological Society, referred to the deviation of the magnetic axis as perhaps due to such shifting of the materials composing the inner mass of our globe. May not the conjectures of M. Elie de Beaumont he after all in the right direction? May not the change of trend which led him to classify the mountain-chains by reference to the age at which they had been ele- vated, be associated with movements which did not in all cases result in shiftings of the earth’s axis so pronounced as those which permitted the Carboniferous and Miocene floras to invade successfully the arctic regions, or the phenomena of the glacial epoch, or epochs, to manifest themselves in the low latitudes where their traces have been recognized ? Waiving, for the present, inquiry into the influence which the admission of a eS ———— << es, Cr, ee ™~ TRANSACTIONS OF THE SECTIONS, 79 pe shifting of the earth’s axis might have on our estimate of geological time, shall return to the phraseology whose amendment seems advisable. The confusion which exists is well illustrated in a remark by an eminent writer to the effect that the ari of geological research tends to prove the “ continuity of geological time.” ‘The phrase in itself involvesan absurdity ; but what is meant is, that the successive so-called formations pass into each other by imperceptible gradation, and that, as time goes on, we shall be more and more able to intercalate strata so as to present a continuous scale of animal and vegetable forms. This is one out of many samples of the extreme length to which the thirst for strict correlation may go. We find in Murchison’s writings and elsewhere pointed pro- tests against the succession of strata in one district being held to rule that in other districts ; but these are rather concessions wrung from their author by the pressure of particular instances than acknowledgments of a rule applicable to contiguous and to distinct localities alike. I could not perhaps take a better example than the strata which contain the remains of the fossil Zguide. If we arrange the fossils in any series representing the modification of particular structures, or averaging the modifications of all the structures, we shall find that the terms of the series are met with, now in Europe, now in America; yet no one would venture to intercalate the European in the American Tertiary series so as to square the geological record with an assumed zoological standard. The notion of gradations, the extreme view of correlations, has led to results which are, to put it mildly, of doubtful value. Yet it was a natural result of the work of Cuvier and other paleontologists among the Mesozoic and Eocene fossiliferous deposits. The statistical method invented hy Lyell is simply a mode of gradations. Intercalation of strata is therefore a survival from an earlier stage of the science, and carries with it a distinct echo of the catastrophic notion that strata were formed simultaneously and generally over the earth’s surface, if not universally. The geological record has been compared to a volume of which pages have here and there disappeared; and the incompleteness of the record has been in- ferred from the frequency of pronounced gaps in the succession of strata. Of these gaps, these unconformities, Prof. Ramsay has shown the importance by demon- strating that they represent the lapse of unknown, but varying, and in all cases considerable periods of time. The intercalation of strata, assumed to fill up the gap, and hereby to give symmetry to systematic classifications, can only be done by an appeal to the statistical method, a fauna containing forms characteristic of higher and lower beds being assumed to represent an intermediate point in time, whereas it might be equally well claimed as representing an mlermetiots area in space, and as being possibly representative of the whole gap and of some of the strata above and below it. The definition of a formation as representing a certain period of time, still re- peated with various modifications, is to blame for this and several other curiosities of procedure, But the climax of symmetrical adjustments is reached when we find “natural groups ” established—when, in otier words, an attempt is made to show a regular periodicity of phenomena in Geology. Dawson proposed a quaternary, Hull a ternary classification—to neither of which should I now refer, but that the deserved estimation of these writers is apt to perpetuate what seems to be an unsafe view of geological succession. Hull’s arrangement has the merit, by force of its simplicity, of bringing the yainness of the attempt into prominence. Dawson has complicated his classification so as to render it impracticable. A natural group of strata, one in which elevation, deep depression, elevation, record themselves in rocks so as to establish geological cycles, implies several things for which we have no evidence. Most important of all, it implies that the events above noted should recur in every area in the same order, that they should recur at equal intervals of time, and therefore yield equal masses of strata, and, above all, that the superior and inferior limits of each natural and conterminous group should consist of a mass of similar strata, one portion of which shall belong to the earlier, the other to the later group. Here then we have implied, not catastrophic simplicity as regards the strata, but something very like it as regards the subterranean forces. é, My. Hull has not, however, been able to surrender himself wholly to his specula- 8 76 : REPORT—1876. tion. He hasadmitted “ Gaps”—breaks, that is to say, for which he finds no equi- valents in the British series—the strata that should occupy these gaps having been either removed by denudation or never deposited, the British area Deane at these times above water. The concession is fatal to the scheme. But the very use of the word gap recalls the phrases ‘‘ complete” and “incomplete,” and their nearest of kin, ‘‘ base of a formation.” Prof. Ramsay used the word “ break” to mark his unconformities ; but no term has been proposed for “the base of a formation.” The term was in constant use when such base was always claimed to be a conglo- merate. That notion is now exploded; but no distinction is drawn between the lowest bed of a group of conformable strata, and the bed or beds which repose unconformably on those below them. Thus the London Basin has the Thanet beds, the Reading beds, and the London Clay successively resting on the Chalk; and each of these is the base for its proper locality, unless it be asserted that in this and similar cases the lowest beds once covered a wider area and were then removed. But a more important case is presented by the great calcareous accumulations of . the Carboniferous and Chalk series. The Lower Greensand is to the latter series in England what the lowest stratum of the chalk would be if we could get at it. The Carboniferous Limestone rests directly on the Red Sandstone in Central England ; further north it rests on the Calciferous Sandstones. Thus the base of the forma- tion varies according to locality, or rather according to the circumstances of depo- sition; and we need a term which would indicate a difference between the conform- able and unconformable succession. Mr. Judd has lamented the equivocal use, by English writers, of the term formation, which etymologically is as well applied to the Chalk without flints as to the whole Cretaceous series. He advocates “ system” as applicable to the larger groups—the Cretaceous system for example, But it seems as if the time were come for still further restrictions of either or both terms. The analogy of the geological record to an incomplete volume is, like most analogies, at once imperfect and misleading. Rather might the record be compared to the fragments of two volumes which have come to be bound together, so that it is not possible to recognize the sequence. Or perhaps it might be better compared to a universal history in which, by omission of dates, the chronology is thoroughly obscured, and the necessary treatment of each nation by itself conceals the con- temporaneity of events. We have the aquatic record and the terrestrial record; and these two are going on simultaneously. It is as yet, and probably always will be impossible to recognize the marine deposits which correspond to the terrestrial remains, save perhaps in the most recent geological times. We now know that the life of the Cretaceous seas is not wholly extinct in the existing Atlantic Ocean, but exists there to an extent which would entitle the deposits of that area to rank by the statistical method as intermediate between the Cretaceous and the Tertiary. It is obviously impossible to include under one term deposits which are associated with geographical changes so important as those commonly accepted as having prevailed during the Tertiary epoch. The Mesozoic forms pass gradually into the Tertiary ; how gradually we cannot say, since the deep-sea equivalents of the European Tertiaries are not certainly known tous. But as a portion survives to the present day, and as, presumably, the extinction was not rapid (for it is only in the case of land-animals that sudden disappearances are as yet probable), it is obvious that the successor, the heir, of the Chalk was not the Eocene, nor necessarily the Miocene known to us, but probably deposits still buried under the Atlantic. My object is to show that even the limitation of time which Prof. Tait pre- scribes for us may not after all be too narrow for the processes which haye resulted in ovr known stratigraphy. My. Darwin speaks of the geologic record being the imperfect record of the last series of changes, the indefinite extension of time anterior to the earliest fossiliferous rocks being necessary for the full evolution of organic forms. But is there any ground for the assumption? True that the Laurentians contain fragments of antecedent rock; but were these fossiliferous ? Are they the remains of land surfaces on which living beings flourished? or are they only the débris of the first consolidated portion of the Earth’s crust, on which if organisms existed they may have been the most primitive of our organic series? Mr. Jukes refers to the possibility of such earlier strata having existed; but he wrote when geologists were dominated by the belief in the indefiniteness of geological ,, TRANSACTIONS OF THE SECTIONS. The time. Now we are brought by physicists like Sir W. Thomson and Captain Dutton to face the question, Is there evidence of such earlier masses of stratified de- posits? If we allow to the physical argument all the weight to which its advo- cates deem it entitled, if we accept 15 millions of years, nay, even if we admit 100 millions of years as our limit, it follows that we may still regard the earth as in its first stage of cooling. But when we turn to the geological evidence, all that can be advanced is that the Laurentian strata contain fragments presumably derived from earlier strata ; but metamorphosed fragments among metamorphic rocks are not the most reliable guides, and there is the positive evidence that the Laurentian area has not been covered to any extent, if at all, by later deposits. So far as direct proof goes, therefore, we have none that the earliest known stratified rocks are not also the earliest deposited after cooling. Even if we disregard the limits imposed by the philosophers, liberal though they are in Sir W. Thomson’s hands, the absence of proof that later deposits covered Laurentian areas seems entitled to greater weight than is usually allowed to negative evidence. At best the asser- tion of antecedent strata is an arbitrary one, which any of us is at liberty to con- tradict, and in favour of which no physical evidence, and only zoological prejudices ean be adduced. ‘The earliest stratified deposits known are the Laurentian; and they are, so far as we know, the earliest to have been deposited. But apart from these possible though improbable earlier deposits, geological time is said to be lengthened by the missing strata of later periods. Mr. Croll has given great prominence to this, which is another of the things taken for granted in geology. Commenting on Mr. Huxley’s remark that if deposit went on at the rate of 1 foot for 1000 years, the 100,000 feet of strata.assumed by him to form the earth’s crust would be laid down in the 100 millions of years which Sir W. Thom- son had given as the limit, ‘ But,” says Mr. Croll, “what of the missing strata?” It is commonly said that we have only a part of the deposits of any period, that the last have been denuded away, and that thus the time needed for their deposit and for their subsequent removal are out of our knowledge. This is based on what we see on the shore when the tide rises and falls and washes off at each turn a part of the sand and mud laid down in the interval. But the older deposits were laid down in deeper water than that between tide-marks, and were for the most part laid down during subsidence. Even admitting removal of part of the strata to have taken place during re-emergence, the quantity so withdrawn cannot be proved to represent more than a small fraction of the total. To provide the needed elon- gation of geological time by an appeal to arbitrary speculations is not admissible. Belief on belief is, as Butler says, bad heraldry. The denudation to which im- portance is justly ascribed is that represented by an unconformity. Re-elevation has been accompanied by disturbance of the area from a different centre than that around which subsidence took place. The strata are worn obliquely; and thus thickness of the mass at one place is greatly diminished, though it does not follow in all cases that the maximum thickness of the strata has been affected. The importance—as I deem it, the excessive importance which is attached to the missing strata is asserted by biologists, who apparently unconsciously seek to gain, by prolonging the interval between successive groups, the time which ought rather to be sought for in tracing, were that possible, the migrations of the species which seem to have suddenly died out. In other words, there is a reversion to the older ideas regarding the succession of strata which are embodied in such phrases as the Age of Fishes, the Age of Reptiles, and the like. But the inequality of surface which unconformity involves, entails that other consequence, that the maximum thicknesses of the two masses of deposits do not coincide in position. Hence the thickness of the strata in the area will be exag- gerated, the time spent in deposit also exaggerated, if the two thicknesses ¢re put together. This has been done by Mr. Darwin in drawing inferences from the mea- surements given him by Prof. Ramsay, measurements which, on the face of them, do not represent a continuous pile of rock. Mr, Darwin assumes either that the Welsh hills (not to speak of the Hebrides) were covered by all the later strata now denuded—or that if we sunk a bore, say on the erst coast, we should go through the whole series as tabulated. When Prof. Huxley took 100,000 feet as the thickness of the sedimentary series, the same notion was unconsciously present, 78 REPORT—1876. the same survival of catastrophism—the onion-coat theory, as Herbert Spencer named it. i The Geological Survey has corrected its tables in one important direction: it has shown the contemporaneity of unlike groups in different parts of Britain, the distinct types of the Old Red Sandstone, Carboniferous, Permian, and Purbecks being placed in parallel columns. To some extent this is a curtailment of the thickness of the rock series, the dissimilar strata are not piled on each other. But the curtailment might be carried still further. The marine and terrestrial con- ditions are simultaneous: if we could identify the dry land for each deep sea, we should have possibly the overlap of periods producing extraordinary combinations, though not perhaps Mesozoic and Paleozoic faunas contemporaneous, But the British series may be tabulated as follows :— Land Surfaces. Lacustrine § Fluviatile. Marine, Laurentian ? Cambrian. Silurian. Old Red Sandstone. Coal Measures, Calciferous Sandstones. Carboniferous Limestone, Permian. Trias. Jurassic, Purbeck. Wealden. Neocomian, Miocene. Pleistocene. Cretaceous, In the case of the Cretaceous series, Mr. Ramsay has given illustration of the ingenious views of De La Beche regarding the contemporaneity of deposits super- posed one on the other. The Lower Greensand is contemporaneous with part of the Chalk; so were parts of the Wealden: nay, even of the Purbecks a portion must have been forming while the Cretaceous sea was gradually deepening southward and eastward. It may be said that the recognition of the parallelism would not make very much difference after all—that it would not one whit lessen the time spent in forming 500 feet of rock to know that there was elsewhere another 500 feet formed at the same time. But the shortening of the geological list by striking out the overlaps of the formations, and thus counting them only once, is of itself a matter of some conse- quence, since, the maximum thiclmess of the Cretaceous being nearly 3000 feet and that of the Weald 1500 feet, even the partial coincidence in time of these masses would, on Mr. Croll’s calculation of 1 foot of deposit per thousand years, make a considerable difference in the chronology, still more if the Carboniferous Lime- stone be set against its probable contemporaries the Upper Old Red Sandstone and Coal-Measures. Mr. Jukes’s bold erasure of the Devonians was of itself a very im- portant change in the chronological table ; and I doubt not others may yet be achieved. But, it may be said, the Cretaceous still rests on the Wealden; the ver- tical thickness still remains. But is the ordinary method of estimating the thick- ness quite reliable? In some cases, as in the productive Coal-Measures, there is tolerable uniformity ; but among the lower Coals and the Mesozoic strata, where the strata or groups of strata are not regular, the maximum thicknesses of all are, as has been already shown, apt to be taken ; and thus an aggregate more or less in excess of the real thickness results. But, recurring to an objection already referred to, arrange it as you like, you get, say in Wales, a known thickness of 50,000 feet. But the rocks there are tilted; and the absolute depth which they attain in this position isunknown. In North Ame- rica the Laurentians are estimated at 30,000 feet ; but though there is every reason to believe that they have not been covered to any extent with later deposits, the total thickness of the sedimentary crust is, for the same reason as in Wales, unknown. Bigsby has shown how varied are the surfaces on which the later deposits are laid down; how great therefore must be the deductions from the sum total of maxi- mum or even.average thickness of all formations before we approximate to the actual thickness of sedimentary deposits at any one point. But take the actual TRANSACTIONS OF THE SECTIONS. 79 thickness in Wales as given in Jukes’s Manual from the Survey data: for the Cam- brians we have from 23000-28000 feet ; Silurians, Upper and Lower, not counting breaks by unconformities, 20000, If denudation takes place at the rate of 1 foot in 6000 years, and deposit at the same rate, we should have for the Silurians alone 120 millions of years needed. If, however, deposit takes place at the rate of 1 foot in 14,400 years, 288 millions of years would be needed for the accumulation of the surviving strata. It is obvious that the rate of deposit or denudation or both are misunderstood. The stratified rocks equal in amount the material denuded; if we Imew the total amount of denudation we should know, not merely the residuum of rock open to our inspection, but the total amount of stratified deposits which had been formed—or at least approximately ; for the deposit of ‘materials removed is not synchronous with their removal. Obviously these elements are not known, and cannot be known, to us. Mr. Croll, who has investigated the question theoretically, assumes that deposit and denudation take place in eyual times, and assumes further a uniform distribution over the whole or over a part of the sea-bottom. But Prof. Geikie’s table shows that, if we are to take averages as a’ safe guide, the land is lowered at the rate of 2 feet in 6000 years. Moreover, if, as Mr. Croll points out, deposit was less during the Glacial epoch, the process must have been more rapid since; and thus an irregularity is introduced which impairs the value of the calculations. Prof. Hughes, in the brief abstract of his Royal-Institution address which alone I have had the opportunity of seeing, contests the validity of any esti- mates of time on the basis of our existing knowledge. 1 do not mean to enter into this question; but I may be allowed to remark that any conclusions founded on mean thickness of sedimentary formations are of no value. It is not the time necessary for the building-up of a mean thickness, but that necessary for the formation of the maximum thickness in particular regions, which we have to consider. If the Laurentian rocks and their equivalents are to be regarded as the earliest stratified deposits, or, rather, if there is no reason for believing that they were pre- ceded by other stratified rocks, the relation of Huxley’s homotaxis to any classifi- cation of strata having the Laurentians as a fixed point is worth investigating. The universal diffusion of species in the earlier strata was first the accepted creed of geologists. Then it was denied, though the language of the earlier faith con- tinued current. Again we return towards the doctrine of extensive simultaneous diffusion, but under a very much modified form. The ‘Challenger’ reports bear testimony to the wide distribution of forms in the deepest oceans; and when we turn from these and compare the lists of fossil species so found widely distributed, it appears that here again we have oceanic forms, or at any rate those found in such limestones as are safely assigned to a deep-water origin. Ramsay has shown that the continental epochs in Western Europe overlasted considerable periods of time. The antiquity of the Atlantic and Pacific is certain; even their primitive character is possible. Thus there are two conditions, land and deep-sea, reasoning regarding which must be quite different from that applicable to the intermediate conditions. It is exactly these intermediate states which present practical and speculative difficulty. Theories which account for mountains and oceans fail to explain the “ oscillations” which were wont to be appealed to when terrestrial and marine sur- faces succeeded each other. But the assumed movement of the land is by no means a certainty ; and, as in the kindred case of faults, we need terms which shall be neu- tral, whether the land has moved upwards or the sea shrunk downwards. The terms Palzeozoic, Mesozoic, and Cainozoic have long held their places from the re- luctance to disturb established nomenclature, as well as from the difficulty of in- venting appropriate substitutes; but if retained at all, we know now that the rela- tions they represent are not the same for the terrestrial, the deep oceanic, and the _ intermediate areas, any more than the life is the same under those three conditions. I have once before called attention toa grave difficulty in the physical geography of Scotland ; and as Mr. Seeley has since then raised the same question without ob- taining an answer, I would again state the case, as one which seems to involve the revisal of some definitions. The Silurian hills of South Scotland are commonly said to have been covered by Old Red Sandstone and even by Carboniferous strata—patches of these rocks being met with on the south side of the fault which defines these hills, with their abrupt, 80 REPORT—1876. coast-like margin seen from Edinburgh or from Symington station on the Caledo- nian line. But the surface of these Silurians was denuded before the Old Red times, as Mr. Geikie has showed. Nay, valleys existed as now, and in the same positions as now. At the present time the rivers flow in identically the same valleys, in at least the cases of the Nith, the Annan, the Lauder, and the Liddell; and the boundaries of the areas are so well known that we can safely assert no buried channel to exist such as we find on the tributaries of the Clyde. That the channels were occluded in glacial times we may take for certain; that the obstruc- tion has been washed away and the courses cleared is equally certain. The surface- contours were not materially altered; so that the retreating ice left hollows in the position of the old valleys. But the case is quite different when we deal with the older rocks, Their succession is marked by unconformities and overlaps, which it is impossible to picture as associated with full preservation of the surface-features on which they were laid down; and when the thickness comes to be as much as 1000 feet or more, and of that thickness a part at least made up of marine strata, the relapse of all the streams to their old courses is an event of the highest impro- bability. Mr. Topley has pointed out how the dip of strtta may under certain cir- cumstances coincide with their thinning out to the margins of their area of deposit, changes of angle in highly inclined strata pointing in the same direction, The ordinary rule, of protracting strata and thus restoring their thickness over the adja- cent high ground, is (in the case at least of South Scotland) a method which imposes on atmospheric denudation, even if aided by the sea, a most complicated task. Had time permitted, it might have been interesting to note the changing phrase- ology regarding faults, and the pertinacity with which phrases involving the most unsatisfactory and improbable causation continues to be used. Upcast and down- cast, upthrow and downthrow, displacement upwards or downwards—these it may be said are of small importance; they are only symbols. But, in the first place, they are mischievous so far as they give students confused ideas with which to contend ; and, in the second place, the continued acceptance of loose phraseology is peculiar to geology. Even in metaphysics, where the subject-matter is much more conveniently discussed in ordinary language, new terms are employed to a great extent. But, important as I therefore regard these terms from the teacher’s poiut of view, the greater importance attaches to the accuracy of the notions which underlie our language regarding the processes and rates of deposit and denudation, So far as our present knowledge goes, we must accept it as certain that there is some limit to the duration of the earth in the past. Neither philosophers nor as- tronomers are agreed on the essential points of the problem; nor have they consi- dered all the possible changes in the position of the earth’s axis, and in the rate at which the earth loses heat. The limits hitherto prescribed are so discrepant that we cannot as yet accept any as fixed. Neither have geologists so accurate a know- ledge of geological processes that they can speak with confidence either of the ab- solute or relative rates at which rock-formation has advanced. The geologist has hitherto asked for more time, not because he himself was aware of his need, but from a generous regard for the difficulties in which his zoological brother found himself when he attempted to explain the diversity of the animal series as the result of slowly operating causes. The geologist asked for more time simply because he could form no just estimate of what was needed for the physical processes with whose results he was familiar. But paleontological domination is now at an end; and the increasing number of geologists who are also competent physicists and mathematicians seems to mark a new school, which will strive to interpret more precisely the accumulated facts. Such at least seems the history of the past fifteen or twenty years. Such seems the direction in which speculation now tends ; and in the foregoing remarks I have endeavoured faithfully to represent the drift of ourscience. To many here present much of what I have said is already familiar ; I therefore give place to the more legitimate business of the Section, looking to receive elsewhere “such censures as may be my lot.” _—— ey eo TRANSACTIONS OF THE SECTIONS. 81 On the Physical Structure of the Highlands in connexion with their Geological History. By His Grace The Duxe or Areyit, A.T., P.RS., F.GS.* The questions dealt with by Geological Science have now become so vast and various, that no one district of country can be expected to furnish illustrations of mire than a very few of them. The West of Scotland, in the capital of which we are now assembled, is not rich in deposits which illustrate the passage of animal life from the types that have become extinct to those which are of more modern origin and which still survive, No bone-caverns of importance have been discovered, and, with one exception, eyen our river-gravels and estuarine deposits have not been especially productive. That exception is, indeed, a great one. It was in this valley of the Clyde that the late Mr. Smith, of Jordan Hill, first discovered those indications of an Arctic climate recently prevailing which have ever since constituted a large and important branch of geological inquiry, and the full interpretation of which still presents some of the most curious and difficult problems with which we have to deal. But our Paleozoic areas, except the Coal Measures, are to a large extent singularly unfossiliferous. Neither the Scottish Oolite nor Lias has yielded any remarkable additions to the curious fauna of which in England and elsewhere they have yielded abundant specimens. But, on the other hand, perhaps no area of country of equal extent in any quarter of the world presents more remarkable phenomena than the West of Scotland, in connexion with those causes of geological change which have determined the form of the earth’s surface, and have given to its physical geography those features of variety and beauty which are the increasing delight of civilized and instructed men. We cannot descend the course of this river Clyde to the noble estuary in which it ends without having presented to us mountain outlines and an intricate distribution of sea and land which raise questions of the highest interest and of the greatest difficulty. From the northern shores of that estuary to Cape Wrath, in Sutherland, the country is occupied mainly by rocks of Silurian age, but so highly crystalline as to be almost wholly destitute of fossils, and so upheaved, twisted, contorted, and folded into a thousand different positions, that, except in one great section, it is most difficult to trace any persistent succession of beds. It is one great series of billowy undulations traversed by glens and valleys, some of which are high above the level of the sea, but many of which are now so deeply submerged that through them the ocean is admitted far into the bosom of the hills. These glens and valleys lie in many different directions; but there are so many with one prevalent direction as to give a general character to the map, a direction from N.E. to 8.W., or parallel to the prevalent strike of the Silurian rocks. The shapes of the hills and mountains are not by any means wholly without relation to geological structure—because in a thousand cases the sloping outlines will be found to be determined by the inclination of the beds, and the precipitous or steeper out- lines to be determined by the upturned or broken edges. In hke manner there are cases where a crumpled or knotted outline is the index of beds deeply folded and contorted along anticlinal axes. But nevertheless there are also innumerable cases where no such relation can be traced ; where the mountains seem to have been cut out of some solid mass, all the rest of which has been removed by some agency which left these great fragments standing by themselves, and of which the con- tours cut across the lines of structure at every variety of angle. Along the whole western face of this country it is guarded from the open ocean by an archipelago of islands, some of which are separated from the mainland by submerged valleys no broader than those which separate one hill from another in the inland glens. Many of these islands are wholly occupied by the débris and the outbursts of extinct voleanoes. The mountains which are thus composed bear, in many cases, the characteristic forms of lava-streams; but many others are not readily distinguish- able in outline from the mountains of wholly ditterent material which are near them. They reach the same general average level of height, here and there rising into peaks very similar to others of a widely different age and of a widely * Printed in full by order of the Council. 1876, 9 82 REPORT—1876. different material. Moreover all the islands partake largely of the general character of the mainland in having their deeper valleys submerged, and in being thus deeply indented by arms of the cea similar to those which give their peculiar out- line to the adjacent coasts. It may serve to bring more vividly before you the facts of the physical geography” of this country (for which it is one of the duties of geologists to account if they can) if I give you some statistical facts affecting the single county of Argyll, which begins on the northern shore of the Firth of Clyde. Following the coast- line of that county from the head of Loch Long, which is its southern and eastern boundary, to Loch Aylort, which is its northern and western boundary, and including its islands, we find it measures no less than 2289 miles in length, of which about 840 represent the sinuosities of the mainland, and 1449 represent the coast-line of its larger islands. There are, besides, yalleys which are now inland, and are occupied by freshwater lakes which evidently, at a recent period, were arms of the sea; and these represent a further line of coast, measuring 276 miles. ‘There are 1] principal arms of the sea, each of them measuring from one to six and thirty miles in length. Two of these arms of the sea exceed the 100- fathom line in depth—Loch Fyne and the Linnhe Loch ; and it is very remarkable that these deep soundings do not occur near the points where these locks join the more open ea nt on the contrary, far up their course or bed among the mountains. The ridges dividing these and other valleys vary in elevation from hills of very moderate height to the range of Cruachan, which immediately beyond the boundary of the county culminates in Ben Nevis, which rears its head almost on a level with Ben MacDhui, now ascertaimed to be the highest summit in the British Isles. But no statistics can give an idea of the intricacy with which sea and land are interfolded on our western coasts comparable with that which is gained by some of the many beautiful views which abound on the heights in the vicinity of Oban, whence the visitor can command the entrance of Loch Istive, with the course for many miles of the Linnhe Loch, of the Sound of Mull, the Sound of Kerrera, and the Firth of Lorne. Now the question naturally arises—to what geological ages and to what geological causes do we owe, in its main features, this curious distribution of land and sea? I say in its main features, because, of course, the more superficial sculpturing of every mountainous country is undergoing incessant modification ; and this modification may have been, and probably has been, very considerable indeed within times which, geologically speaking, belong to the existing age. But the question I put has reference to the epoch of past time, when the main outlines of hill and valley were determined ; when the great mass cf the country (which has been, I believe correctly, identified as composed of metamorphosed Silurian beds) was elevated into the various mountain-chains which now constitute its charac- teristic features. If the question had been asked some five and twenty years ago, I should have said that the evidence pointed to an age of great geological antiquity for the central group of Highland mountains, in some shape very like that in which we see them. AJ] round the edges of the country there are the remains of the Old Red Sandstone, which often fit into the contour of the valleys and have left fragments in nooks and recesses of the hills. It would almost seem as if they had been the shores of the seas or great lakes in which that great system of deposits was laid down, and that they lifted their heads above those waters in forms not wholly unlike those in which we now see them. The total absence over almost the whole country of any other or later rocks, the absence among the débris of any material other than that of which the hills are themselves composed, would seem to confirm the same general conclusion. Some doubt, however, may seem to have been thrown on this conclusion, since it has become certain that it cannot be true of at least one: district of our western mountains, which is neyertheless closely related to all the rest, having the same general elevation, partaking of the same generel bend of coast-lines, cut up by similar valleys, and fitting into the same contours of denudation. ‘The district to which I refer is that of the volcanic islands which stretch from the south end of Mull to the north end of Skye, Since the discovery, which I was fortunate enough to make in 1851, of the leaf-beds of Ardtun, it has become clearly ascertained that these islands are the remains of volcanoes of that geological age to which an ever- increasing interest seems to attach—that middle age of the great Tertiary division of. geological time to which Lyell gave the name of Miocene. The mountains of Mull, and of Higg, and of Rona, and of Skye, with all their valleys and intricate lines of coast, have unquestionably an origin later than the Miocene—how much later, is the question of physical geography which geologists are called upon to solve. It is possible, indeed, to suppose that the hills of the mainland might be of a very different age from those of the adjacent islands; and against this, until some two years ago, there would have been nothing to advance except the suspicious similarity and adjustment between the two groups, the coincidence of their out- lines, and of the way in which they have been cut and carried. But the admirable researches of Mr. Judd, in 1874, have brought one little fact to light which speaks volumes for the enormous changes which must have taken place since the volcanoes of the Miocene over a portion at least of the Highland area, and which may, therefore, have taken place over the whole of it. The land upon which the Miocene vegetation flourished, and upon which the lava-streams of its volcanoes were poured out, seems to have been for the most part a land consisting of Cre- taceous and Secondary rocks. The fragments of that country which remain are generally consistent with the supposition that they were deposited in a sea which washed round the bases of the Highland mountains, but which never covered them. Like the fragments of the Old Red Sandstone, the remains of the Secondary rocks lie along the margins and fringes of the Silurian hills. But Mr. Judd has made the startling discovery of an outlier of the whole series of the Secondary rocks, including representative beds of the Trias, Lias, Greensand, and Chalk, to- gether with deposits, probably Lacustrine, all lying on the top of one of the moun- tains of metamorphic gneiss which constitute the district of Morven. This fragment has been preserved by having been covered by a sheet of lava from some great neigh- bouring volcanic centre, the position of which is probably indicated by Ben More in Mull. But the mass of volcanic trap which has covered up and preserved this relic of the Cretaceous land is itself a fragment occupying the top of a mountain of gneiss, separated from the remainder of the sheet of lava to which it belongs by deep valleys, precisely similar to those which divide the hills from each other _ throughout the whole area of the Highlands. This position of an outlier of the _ Cretaceous rocks on the summit of a mountain of gneiss is rendered still more curious by the circumstance that in that position the beds are not tilted or in any _ way apparently disturbed. They are arranged horizontally, as if the ocean floor in _ which they were deposited had occupied that level, or as if its deposits had been _ lifted up over so large an area that any small section of that area could retain its original horizontality. The Lower Silurian gneiss beds on which these Secondary deposits have been laid are violently twisted and contorted; and this structure must have belonged to them when they constituted the floor of the Cretaceous sea. The position of the Miocene basalts capping the Secondary deposits proves _ that the whole mountain, as a mountain, is of later date than the Miocene age— how much later we cannot tell; and thus that the causes of geological change which have cut up the country into its present form, though they doubtless began in yery remote epochs, have at least been prolonged into a comparatively late age in the history of the globe. It would, I think, be affectation to pretend that our science enables us to follow, with any thing like distinctness of conception, the exact nature and sequence of _ operations which through such a vast lapse of time have brought about the final result. But I believe in something like the following general outline of events. First. That subsequent not only to the consolidation, but probably also to the metamorphism of the Lower Silurian deposits, the whole area of the Western- - Central Highlands became an area of that kind of disturbance which arose from - lateral pressure due to secular cooling and consequent contraction and subsidence _ of the crust of the earth. _ Second. That the crumpling, contortion, and tilting of the Silurian beds which "we now see arose from that disturbance. Third. That then were determined those great general lines of strike running o* TRANSACTIONS OF THE SECTIONS. 83 84. REPORT—1876. from N.E. to S.W. which are to this day a prominent feature in the physical geography of the country. Fourth. That during that period of disturbance, and as part of the movements which then took place, the disturbed rocks fell inwards upon materials at a great heat, which rose in a pasty state along the lines of least resistance, and thus came to occupy various positions, sometimes intercalated among the sedimentary beds. Fifth. That to this period, and to this method of protrusion we owe some at least of the masses of granitic material which are abundant in the Highlands. In particular, that to this period belong the porphyritic granites on the northern shores of Loch Fyne. Sixth. That during the later ages of the Palzeozoic period, volcanic action broke out at various points, accompanied by great displacement and dislocation of strata, and that to this, with the denudation which followed, we owe much of the very peculiar scenery of the south-western coasts, especially in the district of Lorne in Argyllshire. Seventh. That we have no proof that the Central Highlands were ever under the seas which laid down the deposits of the later Paleozoic age. Eighth. That such evidence as we have points rather to the conclusion that they were not under those seas, since such fragments as remain of the Old Red and of the Carboniferous rocks appear to have been deposited round the bases and in the marginal hollows of the Silurian hills. Ninth. That in like manner we have no evidence that the great mass of the Western or Central Highlands was ever under the seas of the Secondary ages, which on the contrary, appear to have deposited their sediment upon an area outside of, but probably surrounding, the area of those Central Highlands, and certainly upon their north-eastern and western flanks. Tenth. That the whole area of the Inner Hebrides and of the waters dividing them, together with some portion of the mainland, as in Morven, was an area occupied by Secondary rocks. Eleventh. That in the Tertiary ages, probably in the Kocene, and certainly in the Miocene, these rocks formed the basis of a great land of unknown extent, very probably extending for a great distance both to the east and west of the present coasts of Scotland, and embracing the north of Ireland. Twelfth. That this country became in the Miocene age, and possibly earlier, the scene of great volcanic outbursts, which covered it with vast sheets of lava and broke up its sedimentary rocks with every form of intrusive plutonic matter. Thirteenth. That later in the Tertiary periods, and perhaps as late as the Pliocene, this voleanic country was itself broken up by immense subsidences and upheavals, giving both occasion and direction to the agencies of denudation and to enormous removals of material. Fourteenth. That this Tertiary country had been thus broken up and nothing but its fragments left when the Glacial epoch began, and that the main outlines of the country, as we now see it, had been already determined when glacial conditions were established. Fifteenth. That thus the work of the Glacial period has been simply to degrade and denude preexisting hills and to deepen preexisting valleys. . Sixteenth. That during the Glacial epoch there was a subsidence of land to the depth of at least 2000 feet below the level of the present sea, and again a reelevation of the land to its present level. Seventeenth. That this reelevation has not restored the land to the level it stood at before the subsidence began, but has stopped greatly short of it; and that the deep arms of the sea or lochs which intersect the country, and some of the deeper freshwater lakes, such as Loch Lomond, are the valleys still submerged which at the beginning of the Glacial epoch where high above the sea and furrowed the flanks of loftier mountains. Eighteenth. That during the Glacial period the working of denudation and degradation was done, and done only by ice, in the three well-known forms :—1st, of true glaciers descending mountain-slopes; 2nd, of icebergs detached from the termination of these glaciers where they reached the sea; and 38rd, by floe or — JOE TRANSACTIONS OF THE SECTIONS. ‘85 surface ice, driven by currents which were determined in direction by the changing contours of the land during the processes of submersion and reelevation. It would be impossible on this occasion to illustrate or support these various propositions by going into the evidences on which they rest. Butas those of them which relate to the operations of the Glacial epoch express a decided opinion upon uestions now involving much dispute, I must say a few words in explanation and defence of that opinion. It will be seen that I disbelieve altogether in the theory of what is called an Ice-cap ; or, in other words, I hold that there isno evidence that there ever existed any universal mantle of ice higher or deeper than all the existing mountains, cover- ing them and moving over them from distant northern regions. In the first place, this theory presupposes conditions of climate which must have prevailed universally over the whole northern hemisphere; whereas over a creat portion of that hemisphere west ofa certain meridian on the American continent, all traces of general glaciation and of any general distribution of erratics disappear. In the second place, the theory assumes that masses of ice lying upon the surface of the earth, more than mountain-deep, would have a proper motion of their own, capable of overcoming the friction not only of rough level surfaces, but even of the steepest gradients, for which motion no adequate cause has been assigned, and which has never been proved to be the natural consequence of any known force, or to be consistent with the physical properties of the material on which it is ew to have acted. n the third place, as a matter of fact there do not now exist anywhere on the globe masses of ice which can be proved to have any motion of this kind, or to be subject to forces capable of driving and propelling it in this manner and with the effects which the theory assumes. The case of Greenland, which is often referred to as an example, does not present phenomena at all similar to those attributed to the ice-sheet. i In the fourth place, all the phenoména of glaciation which are exhibited on the -mmountain-ranges, including the distribution of erratics, can be adequately accounted for by the three conditions or forms of moving. ice which have been above enumerated, and all of which are now in actual operation on the globe, namely :— -ice moving, not up, but down mountain-slopes by the force of gravitation, and ice floated by water and driven by currents as icebergs or as floes. In the tifth place, these phenomena of glaciation are essentially different from those which would result from the motion of a universal ice-sheet, even supposing it to have existed and supposing it to have had the (improbable) motion which has been ascribed to it. In the sixth place, and in particular, the mode in which erratics are distributed and the peculiar position of perched blocks are demonstrative of the action not of solid but of floating ice ; whilst the surfaces of rock, which have escaped glaciation on one side and retain the deepest marks of it upon another, are equally demonstrative of exposure to moving ice under conditions which did not enable it to fit into the irregularities of surfaces over which it passed. In the seventh place, the phenomena seem to me to prove that some of the very heaviest work done by ice has been done towards the close of the Glacial epoch—when the land was emerging again from out of a glacial sea, and when all the currents of that sea, loaded with bergs and floes, were determined entirely by the outlines of the rising land. In regard to the much disputed question of the glacial origin of Lake-basins, the conclusion to which I have come is one which, to some extent, reconciles antagonistic views. I do not, indeed, believe that glaciers can ever dig holes deep under the average slope of the surface down which they move; but, on the other hand, they are the most powerful of all abrading agents in deepening their own bed and cutting away the rocky surfaces which lie beneath them. If valleys thus deepened by the long work of glaciers and glacier-streams are afterwards submerged along with the whole country in which they lay, and if that submergence is accompanied by partial and unequal rates of subsidence, they would inevitably become hollows into which the sea would enter, or in which fresh waters would accumulate. In this sense, and in this way, it can hardly 86 REPORT—1876. admit of a doubt that those lakes, which are nothing but submerged valleys, are due in part to glacier action, although the other half of the causation on which they depend is to be sought in the subterranean action of subsidence. n conclusion, I would observe that although the fact of a great subsidence and a reelevation of the land during the Glacial epoch has been generally admitted to be one of the facts of which there is the clearest evidence, it is nevertheless a fact of which all the conditions and all the consequences haye been most imperfectly recognized. Without venturing to go so far back as to imagine the process of subsidence and submergence, let us only think for a moment of that movement of reelevation which has certainly been one of the very latest of the great movements of geological change. Ifit took place very gradually or very slowly, it necessitates the supposi- tion that every inch of our mountain-surfaces, up to at least 2000 feet, has been in succession exposed to the conditions of a sea-beach. Yet where are the marks upon them of such conditions? We may suppose such marks to have been generally obliterated by later subaerial denudation. But against this is to be set the fact that the position and distribution of perched blocks and other erratics deposited by floating ice demonstrate, in my opinion, that very little indeed of such denudation has taken place since they were placed where we now see them. I could take any of you who are interested in this question to a precipitous hill near Inverary, some 1200 feet above the level of the sea, from the top of which you can look down on the masses of transported rock stranded upon its sides and base, ‘precisely as one might look down dons the top of some dangerous reef in the or ocean upon the débris of a whole navy of ships shattered upon it in some hurricane of yesterday. There they lie—some more or less scattered, some heaped upon and jammed against each other, with sharp angles and outlines wholly unworn, and, moreover, 80 distributed that you see at a glance their strict relation to the existing heights and hollows of the land, which must here have been the shoals and channels of the sea. These contours cannot have been materially changed since that sea was there. It seems that it must have been there, ceologically speak- ing, only a very few days ago. And this conclusion would seem to be confirmed when we observe the phenomena which are present in certain cases where the land has clearly rested for a consider- able time and the ocean has left in raised beaches the evidence of its work at certain levels. Such raised beaches are to be found at many points all round our western coasts; but incomparably the finest and most instructive example of them is to be seen on the west coast of the island of Jura, near the mouth of Loch Tarbert, Jura, and extending for several miles to the north. These beaches are visible from a great distance, because their rolled pebbles are composed entirely of the hard white quartzite of the Jura mountains, which resists disintegration and is very unfavourable to the successful establishment of vegetation. I visited these beaches a few weeks ago, and, measuring the elevation roughly with a graduated aneroid, I found that they represent three more or less distinct stages of subsidence, one beach being about the level of 50 feet above the present sea, another about 75 feet, and a third at about 125 feet. Some others, which I saw only from a distance, appeared to be higher; and I believe, but am not quite sure, that further to the north they have been traced to the level of 160 feet. But the feature connected with these sea-beaches, and especially with the lowest or the 50-feet beach, is the evidence it affords, first, of the length of time during which the ocean stood at that level, and secondly, and particularly, of the very recent date at which it must have stood there. As regards the length of time during which the ocean must have stood. there, it is sufficient to observe the beautiful smoothness and roundness of the pebbles; they have been more thoroughly rolled and polished than the corresponding pebbles on the existing shores, equalling in this respect the famous péebble-beds of the Chesil Beach at Portland. Then, as regards the very recent date at which the ocean must have stood there, it is difficult to give in words an adequate idea of the impression which must be left on the mind of every one who looks atthem. You sce the curves left by the sweep of the surf, the summit level of its force, and the hollow behind that summit which is due to the exhausted crest—all as perfect as if it had been the TRANSACTLONS OF THE SECTIONS, 87 work of yesterday. Is is difficult to conceive how ordinary atmospheric agencies, and even the tread of sheep and cattle, should not have broken such an arrangement of loose material. . But there are exceptionably favourable circumstances for the preservation of these beds. from absence of considerable streams and the protec- tion of surrounding rocks. There is little or no evidence of glaciation anywhere around; and although it is certain that the sea which stood at those beaches so recently was a sea subject to glacial conditions, it is equally certain either that it continued to work there after those conditions had passed away, or, what is more robable, that that particular line of coast was protected from the drift of surround- ing ice-floes, If, now, we compare the evidence of recent action in these sea-beaches with the similar evidence connected with the position of erratics at far higher levels, which can only haye been placed there by floating ice, I cannot help coming to the con- clusion that the submergence and reelevation of the land to the extent of more than 2000 feet above the level of the present ocean has been one of the very latest changes in the history of this portion of the globe ; and, moreover, that the reeleva- tion has been comparatively rapid, probably by lifts or hitches of considerable extent, and that there were few, ifany, pauses or rests comparable in duration with those recorded in the Jura beaches and in the cutting of the existing coasts. Finally, let me repeat that whether this conclusion is correct or not (and I am well aware of the many difficulties which surround it), the general fact of sub- mergence and reelevation is, perhaps, as certain as any conclusion of geological scieace, and that the consequences of it in accounting for the distribution of gravels and the most recent changes of denudation have never as yet been worked out with any thing approachiag to consistency or completeness, On the Sub- Wealden Exploration, By Major Beaumont, MP. On the Granite of Strath-Errick, Lough Ness. By Janes Brycx, LL.D. The author described a granite tract a little distance from the shores of Loch Ness, and near the Fallof Foyers. This fall took place originally over a cliff of Old Red Sandstone, and this stone being of a soft character gradually wore away until it formed a magnificent basin almost inaccessible at the bottom, and the action of the water had also worn the rock back to the slate which came between it and the eranite. His attention had been called to the Loch-Ness granite tract by hearing that gold had been found in the lower valley of the Nairn, which passes through this granite district, and he supposed it probable that the gold might have its source in this granite tract in the same way as he had found the granite of Suther- land to be the true source of gold. After describing the limits of the granite tract, he pointed out a most remarkable circumstance connected with its history, which was illustrated by a section in a glen above Innerfaricaig. Tere this triple granite rises from the valley in a direction sloping eastward, at first leaning against the Old Red Sandstone, and ultimately, further east, reeularly overlying it, the metamorphism being very remarkable through about 2 foot of depth, and portions of granite being embedded in the Old Red. On the east side of the hill the Old Red Sandstone was regularly overlapped by granite, the strata of the Old Red dipping under it at an angle of 82 degrees. The well-known vitrified fort on the top of the hill contains both rocks highly vitrified. To the west of this another hill rises composed at the base of OldRed,andits upper part consisting of conglomerate granite. He called the attention of the Section specially to this conglomerate granite, and to the evidence which the whole district afforded that the granite here was truly inruptive, and not of that hydrothermal origin to which the granites further east have been ascribed. The only conglomerate granite similar to this with which he was acquainted was one that he had visited some years ago at Forkhill, county Armagh ; and he called attention, especially of Professor Hull, to the connexions of these beds to the probable origin of a great irruption of granite. — 88 ; REPORT— 1876. On the Earthquake Districts of Scotland. By James Bryce, LL.D. On the Tidal-Retardation Argument for the Age of the Earth. By Jamus Croxt, LL.D., #.RS., of the Geological Survey of Scotland. Many years ago Sir William Thomson demonstrated from physical considerations that the views which then prevailed in regard to geological time and the age of our globe were perfectly erroneous. His two main arguments, as are well known, were, first, that based on the limit to the sun’s possible age, and, secondly, that based on the secular cooling of the earth. More recently he has advanced a third argument*, based on tidal retardation. It is well known that, owing to tidal retardation, the rate of the earth’s rotation is slowly diminishing, and it is therefore evident that if we go back for many millions of years we reach a period when the earth must have been rotating much faster than now. Sir William’s argument is, that had the earth solidified several hundred millions of years ago, the flattening at the poles and the bulging at the equator would have been much greater than we find them to be. Therefore, because the earth is so little flattened, it must have been rotating when it became solid at very nearly the same rate as at present. And as the rate of rotation is becoming slower aud slower, it cannot have been so many millions of years back since solidification took place. A few years ago I ventured to point outt what appeared to be a very obvious objection to the argument, viz. that the influence of subaérial denudation in alter- ing the form of the earth had been entirely overlooked ; and as the validity of the objection, as far as I am aware, has never been questioned, I had been induced to believe that the argument referred to-had_been abandoned. But I find that Pro- fessor Tait, in his work on ‘Recent Advances in Physical Science,’ restates the argument as perfectly conclusive, and makes no reference whatever to my objection. As the subject is one of very considerable importance, I may be permitted again to direct attention to the objection in question, which briefly is as follows :-— It has been proved by a method pointed out a few years ago}, and which is now generally admitted to be reliable, that the rocky surface of our globeis being lowered on an average, by subaérial denudation, at the rate of about 1 foot in 6000 years. It follows as a consequence from the loss of centrifugal force resulting from the retardation of the earth’s rotation, occasioned by the friction of the tidal wavs, that the sea-level must be slowly sinking at the equator and rising at the poles. This of course tends to protect the polar regions and expose equatorial regions to subaérial denudation. Now it is perfectly obvious that unless the sea-level at the equator has, in consequence of tidal retardation, been sinking during past ages at a greater rate than 1 foot in 6000 years, it is physically impossible that the form of our globe could have been very much different from what it is at present, whatever may have been its form when it consolidated, because subaérial denudation would have lowered the equator as rapidly as the sea sank. But in equatorial regions the rate of denudation is no doubt much greater than 1 foot in 6000 years, because the rainfall is greater there than in the temperate regions. It has been shown in the papers above referred to that the rate at which a country is being lowered by subaérial denudation is mainly determined, not so much by the character of its rocks as by the sedimentary carrying-power of its river-systems. Consequently, other things being equal, the greater the rainfall the greater will be the rate of denudation. We know that the basin of the Ganges, for example, is being lowered by denu- dation at the rate of about 1 foot in 2300 years, and this is probably not very far from the average rate at which the equatorial regions are being denuded. It is therefore evident that subaérial denudation is lowering the equator as rapidly as the sea-level is sinking from loss of rotation, and that, consequently, we cannot infer * Trans. Glasgow Geol. Soe, vol. iii. p. 1. i t ‘Nature,’ August 21, 1871; ‘Climate and Time,’ p. 335. t ‘Philosophical Magazine,’ May 1868, pp. 378-384, February 1867, p. 130; ‘Climate and Time,’ chap. xx.; Trans. Glasgow Geol, Soe, yol. iii. p. 153. TRANSACTIONS OF THE SECTIONS, 89 from the present form of our globe what was its form when it solidified. In so far as tidal retardation can show to the contrary, its form, when solidification took place, may have been as oblate as that of the planet Jupiter. There is another circumstance which must be taken into account. The lowering of the equator by the transference of the materials from the equator to higher lati- tudes must tend to increase the rate of rotation, or, more properly, it must tend to lessen the rate of tidal retardation. On the Variation in Thickness of the Middle Coal Measures of the Wigan Coal-field. By C. E. Dr Rance, F.GS., of H.M. Geological Survey. From the Arley Mine, the lowest coal-seam of this series, to the Ince-Yard Coal, at Worthington, north of Wigan, the measures are 2200 feet in thickness, thinning 50 feet per mile to the 8.W. to Prescot, where the measures are only 1445 feet in thickness, and 57 feet per mile to the N.E. towards Burnley, where the measures between the equivalents of these coals are only 1000 feet in thickness—proving the Wigan coal-basin to be not merely a synclinal of subsidence, but one of deposition, the axis of which was shown to have gradually travelled northwards in time from the district of St. Helens to a point north of Wigan. The importance of arranging colliery sections in a definite geographical direction, and the importance of noting the occurrence of very thin coal-seams and horizons of fire-clay and of seams full of Anthracosia, were insisted on as means of identifying equivalent coal-seams across a district. Great lateral shifts were shown to have occurred between many of the great N.N.W, faults which traverse the Wigan district and divide it up into a series of belts. On Labyrinthodont Remains from the Upper Carboniferous (Gas- Coal) of Bohemia. By Dr. Anton FRitscu, The beds of gas-coal which are now being worked at so many localities, both in Europe and America, serve not only to illuminate our chambers, but to throw fresh light upon many branches of paleontological science; for these beds of gas-coal have been found to yield a remarkably fine-fauna, especially rich in the remains of Labyrinthodonts, fishes, and insects. During the last five years, I have been so fortunate as to discover in Bohemia two localities which afford us beautifully preserved relics of ancient life thus en- tombed in the gas-coals. One of these localities is Nyran, near Pilsen, in the western part of Bohemia; the other is Kounova, near Kakonitz, in the north-west of the country. In both of these places the gas-coals are found to be situated on the top of the Coal-measures proper, but beneath the true Permian deposits. The plants of these beds are closely allied in character to those of the Coal-measures; but the animals ~ ser to be of Permian types. do not intend upon the present occasion to enter into a full enumeration and description of these interesting fossils ; but I take the liberty of submitting to this Section of the British Association series of specimens of casts and of plates of some of these fossils which I have brought to this country for the purpose of comparing them with the similar remains found in the British Coal-fields. The first three plates exhibited contain enlarged drawings of very small Laby- rinthodonts of the group called by Prof. Huxley Microsauria. One of these, not -more than one inch (?) long, has the skeleton completely ossified. The fourth and fifth plates are devoted to a large species. of Labyrinthodon of about 5 feet in length. Among the specimens, the author drew attention to the teeth of a Ctenodus, of which species the bony parts of the skull were found preserved. Of the remarkable genus Diplodus a lower jaw with teeth served to show that these latter are not, as was formerly supposed, the dermal spines of a Ray. Among the insect-remains was observed a new species of Garmsonychus, speci- mens of which cover the whole surface of some slabs of the rock. The restored - 90 ‘ REPORT—1876. drawing illustrated the enlargement of the seventh pair of appendages in this species into swimming-feet. The species of Julus, called by the author J. constens, shows how little the forms of this genus have changed in the interval between Palzozoic and recent times. The rich materials which are now accumulated in the Museum of Prague will require for their illustration about 50 or 40 plates in the monograph which the author is now preparing on this very interesting vertebrate fauna. On the Physical Geology and Geological Structure of Foula. By Guorce A. Gisson, M.B., B.Sc. Edinb. Taking up, in the first place, the physiographical geology of the island, in con- nexion with the agencies involved, the paper describes the coast scenery, and dwells upon the contrast between the low and rugged eastern side and the stupendous cliffs which overhang the western sea. This striking difference is shown to be due partly to the superior powers of resistance to weathering evinced by the materials of the sandstone rocks as contrasted with the crumbling schistose masses, and also to the fact that in the former the strata dip away from the cliffs. The inland features are next taken up in detail. The five hills are found to be on the west side, three of them (Liorafield, the Sneug, and the Kame, which, taken by aneroid, reach 1000, 1250, and 1150 feet over sea-level) forming an axial chain, whilst the other two (Soberly, 650, and the Noup, 700 feet high) are distinct. The last three are noticed as forming precipices from their summits sheer into the sea, and all, except the Noup, which is dome-shaped, as having a conoid outline, the steepest sides of which face the north and east. As the dip is 8.8. W., these hills are therefore held to have a contour in accordance with the empirical law, noted above, that the strata dip away from the side which has the steepest slope, The drainage is of course seen to be easterly. The lithological character of the rock masses is then detailed, along with their architectural features and stratigraphical relations. The eastern side is described as composed of eneiss, very similar to that of Loch Maree, and of mica-schist with intruded veins of granite, having a strike from N.W. to 8.E., agreeing therefore with the presumably Laurentian of Scotland ; this, however, isnot to be regarded as of great significance, on account of the variable strike of similar rocks in Shetland. The sandstone series is shown to be separated by a fault from the metamorphic rocks, running from N.N.W. byN. to §.S.E. by S., and along which dislocation the rocks are changed into hard quartzrock. ‘There is described an unbroken succession of sandstones and flags for two miles, at an average dip of more than 25°, whosoa thickness cannot be estimated at less than 4400 feet. No fossils having been discovered in these rocks, they are then compared in litho- logical character and position with the other sandstones of Shetland. Differences in composition and texture are pointed out to be due to altered conditions of depo- sition, the Bressay and Lerwick flags and sandstones belonging, with the Fouta beds, to the Old Red Sandstone of the Caithness series. On the Red Soil of India. By Dr. Grncuntst. On the Strata and Fossils between the Borrowdaile Series of the Coniston Flags of the North of England. By Prof. Harkness, J2.S., and Prof. A. H. Nicnorson, M.D. On the Upper LInimit of the essentially Marine Beds of the Curboniferous System of the British Isles, and the necessity for the establishment of a Middle Carboniferous Group. By Prof. Enpwarp Horr, .R.S., &., Director of the Geological Survey of Ireland. In this paper the author endeavours to show the equivalent stages throughout TRANSACTIONS OF THE SECTIONS, 91 the British Isles of the members of the Carboniferous system, and divides the whole into successive stages from A to G, thus :— Stages. Name. _ Localities. G. Upper Coal-measures. - Lancashire, N. Wales. F. Middle MY England, Scotland, Ireland. E. Lower ditto, or Gannister Beds. Tngland, Wales, Ireland. D. Millstone Grit. England, Scotland, Ireland. C. Yoredale beds. England, Lower Coalfield of Scot- land, Tveland. B. Carboniferous Limestone. England, Ireland, Calciferous A. Lower Carboniferous Slate, Sandstone of Scotland. grits and conglomerates ; Lower Limestone Shale, These beds are then identified, both by position and paleontological remains, over the whole area, and lead to some important results. Rejecting the evidence ‘of fish- and plant-remains, which are inconclusive, the author finds that there is a strong paleontological distinction between stages E and F—the fauna of the one (E) being essentially marine, that of the other (F) essentially estuarine or fresh- water. The lists of species have been extracted from the memoirs of the Geological Survey, the determination being those of the late Professor E. Forbes, Mr. Salter, and Mr. Baily. The author of this paper is responsible for the determination of the stratigraphical position of the beds from which the species have been obtained. He finds that there are about 53 species of marine genera in stage E (Gannister beds, or Lower Coal-measures)*, of which 33 come up from the Carboniferous limestone, but only 4 or 5 pass up into the overlying stage F (Middle Coal- measures), indicating a strong paleontological break. Again, of 8 marine species found at rare intervals in stage F (Middle Coal- measures), 4 are peculiar to this zone, and the remainder are common to it and stage KE. The remaining species belong to the genera Anthracosia, Anthracomya, &c., which some authorities regard as of freshwater origin, others estuarine; they are probably either: these genera pass into stage G. These differences, together with some of a stratigraphical nature, between stages ¥ and G on the one hand, and E, D, C on the other, are so striking that the author submitted that they should be recognized in the classification of the beds; and he proposed to establish a “ Middle Carboniferous” division, to include all the stages from the Yoredale (C) to the Gannister (1) inclusive. This stage would be essentially marine; while the term “ Upper Carboniferous ” would be restricted to the stages I* and G, which are shown to be estuarine or freshwater. The term Lower Carboniferous would remain as at present, to designate the Carboniferous - Limestone and basal beds of the system, stages A and B. The author has reason to believe, from information supplied by Professor Roemer, of Breslau, that the marine stage E can be identified on the continent, both in Belgium and Germany a band with Goniatites and Aviculopecten occurring about 109 feet above the base of the Coal Measures, while, as we learn from Geinitz, the mollusks of the Coal-formation generally belong to the genus Unio (Anthracosia), so that this remarkable division, with its marine fauna, has had a range as wide as the British Isles and Western Europe, and marks the upward limit of the essen- tially marine conditions of the Carboniferous system. On a Deep Boring for Coal at Scarle, near Lincoln. Communicated by Professor Epwarp Hutt, F.R.S. This boring was undertaken about two years ago by a small company of Lincoln- shire gentlemen under the advice of Mr. J. T. Boot, mining engineer, of Mansfield, from whom I have received information and specimens constantly during the ope- rations, besides having visited the locality in June 1875. he works have been earried out by the Diamond Rock-boring Company, and specimens of the cores were laid on the table. * They have since been considerably added to.—February 1877. 92 hs /-REPORT—1876. The total depth attained up to this time is 2035 feet. The boring commences n the Lower Lias at a spot about 6 miles south-west- of the city of Lincoln, and after traversing the Lias, Rheetic, Keuper, and Bunter beds, the Upper Permian and Lower Permian, it entered the Carboniferous formation at a depth of 1901 feet, the remainder of the section being in Carboniferous strata. The general succession is as follows :— Depth. Thickness. ft. ft. ANIMA Uina pave steal ath wet feted Fine toe Ritevavshahatialerts aOR Melts 10 ‘10 Mowenluiagy Clay oi tiaches «cfyiahe apes 0+ © San paige® urate 60 50 theater eds ae casio a radeaceteoicl ss, 6 aispline a area iar ae 145? 85? K IM etl B ea eles tee oie ee se hanree terra ann pie 706 = 661 Le eo Lower Sandstone .\ nis ene ye yee 958 252 BAM ber SANG SLOME) qadseslciesedere Medes Oks 21 Heke ee (oreeltcl oats oh ueeleyeiokays 1500 542 pais Upper Marls and Magnesian Limestone 1884 384 Soir wating p Lower Sandstone v.00... eee een, 1900 16 (Grey grits with plants; shales with - | small bivalves (Anthracosia) ...... 1955 55 Carboniferous Bluish calcareous shales and earthy Beds ..... 0465 VScc]imestone LOU. AGS OY REARS 2020 65 [rikine breccia. 28s .46 O20. Bad mous . 2024 4 | Chocolate-coloured hard clays ........ 2030 6 The temperature at 2000 feet was 79° F., taken with one of Negretti’s thermo- meters supplied by Professor Everett, of Belfast. At a depth of 917 feet a strong” feeder of water was encountered in the Lower Keuper Sandstone, and a still stronger at 1250 in the Bunter Sandstone, when the water rose 4 feet above the ground. This water unquestionably percolates underground from a distance of 10 or 12 miles, where the beds crop out. This boring is exceedingly interesting as giving the depth of the Carboniferous rocks so far from the borders of the Nottinghamshire coal-field, and as giving the thickness of the overlying formations; but it has (unfortunately for the spirited gentlemen who have undertaken it) not as yet produced any satisfactory results, The Carboniferous beds are of so peculiar a character that I hesitate to attempt to identify them with any particular division of the Carboniferous system. Mean- while, as the boring is still being prosecuted, it is hoped that specimens of a more definite nature may be brought up. On Tertiary Basalt-rock Dykes in Scotland. By R. L, Jack, F.GLS. On some New Minerals, and on Doubly-refracting Gainets. u y J By Dr. Von Lasatx. The writer exhibited specimens of the new wineral which he terms melanophla- gite, in consequence of its peculiarity of becoming black when heated before the blowpipe. It occurs in very small cubic crystals, of pale brown colour, seated on little scalenohedra of calcite, which are associated with the’ sulphur and celestine of Girgenti, in Sicily. According to analyses, melanophlagite contains 86:29 per cent. of silica, 7-2 of sulphuric acid, or some acid of the thionic series not yet de- termined, 2:8 of strontia, 2°86 of water, and small quantities of alumina and ferric oxide. Dr. Von Lasaulx also exhibited specimens of his new species aerinite, and several microscopic sections of garnets which exhibited double refraction. He entered into an explanation of the causes of such optical irregularities in monometric crystals, and referred them partly to the effects of tension, partly to chemical altera- tion, and partly to complexity of structure, due to alternations of isotropic and anisotropic minerals. Thus the variety of garnet called colophonite appears to be a mixture of true garnet and idocrase; hence, whilst one part exhibits single refrac- tion, another part shows double refraction. “oem oO TRANSACTIONS OF THE SECTIONS. 93 On the Changes affecting the Southern Extension of the Lowest Carboniferous Rocks. By G. A. Lesour, /.G.S. In Scotland the lowest division of the Carboniferous series consists of the rocks called “the Calciferous Sandstones” by Maclaren, and usually known in the north of England as “Tuedian.” Prof. Geikie has shown that the lower limit of these rocks merges insensibly into the upper portion of the Old Red Sandstone series. In England their upper limit seems to be equally indefinite, and runs in a kind of lateral dovetailing into the lower beds of the Carboniferous Limestone series or «Bernician.” It is this merging of Tuedian into Bernician which forms the subject of the paper. Some remarks as to the terminology of the series followed, and also a short account of the higher divisions of the Carboniferous as represented in the north of England, pointing out especially that the mode of deposition there was nearly of the same character from the base of the Millstone Grit to the Old Red series, a slight and very gradual change from brackish to purely marine conditions being the only one of a sufficiently marked and important character to be taken into account. The author admits but two Carboniferous divisions—the Upper, con- sisting of Coal-measures, Gannister beds, and Millstone-grit; and the Lower, inclu- ding the Bernician or Carboniferous Limestone and the Tuedian or Calciferous Sandstones. On the Parallel Roads of Glen Roy. By J. MAcFADZEAN. On the Parallel Roads of Glen Roy. By Davip Mitnz-Howr, LL.D. The object of the author in this paper was to notice the views of Dr. Tyndall given in a Lecture on Glen Roy, delivered in the Royal Institution, London, on 2lst June, 1876. The author thought that Dr. Tyndall had allowed to himself too short a time, viz. only two days, for an examination of the Lochaber district, as in that space it was impossible to see more.than a tenth part of the things which should be exa- mined for a solution of the Parallel Roads problem. Dr. Tyndall had apparently gone to the district with preconceived opinions in favour of the glacier theory to explain how the lakes had been confined. His know- ledge of the Swiss glaciers eminently qualified him to see on the spot whatever could be urged in support of that view. But, after all, the result of Dr. Tyndall’s inspection had only satisfied him that there was a “probability” of the correctness of the glacier theory, though a probability so great as in Dr, Tyndall’s opinion to “amount to a practical demonstration of its truth.” To pave the way for the adoption of the glacier theory of lake-barriers, Dr. Tyn- dall began his lecture by attempting to annihilate what seemed to him the only other explanation worthy of notice, viz. that first suggested by Sir Thos. Dick Lander, and defended by Mr. Milne-Home, that the lakes were dammed by detrital blockage. He states that this explanation may with safety be “dismissed as incompetent to account for the present condition of Glens Gluoy and Roy.” Dr. Tyndall, however, seems to have supposed that no better support could be given to the detrital theory except what was stated in Sir Thomas Lauder’s paper, published about sixty years ago, ignoring altogether what had been advanced in support of the theory by later writes, He, for example, states that the detrital barriers were supposed by Sir Thomas Lauder to have been heaped up by “ some unknown convulsion,” a view which no one now suggests, and which Sir Thomas himself never entertained. What is stated in support of the detrital theory is, that a blockage existed at the mouths of the glens, created by the detritus, which then filled the valleys, and which reached even to the mountain tops at heights of nearly 2500 feet above the sea. Dr. Tyndall admits the abundance of detritus at these heights, and even allows ‘that the Parallel Roads were formed on the detritus. Glen Collarig shows that the barrier there must have been only 700 or 800 yards 94 REPORT—1876. in length and about 300 feet in height, as the lakes in that Glen must have been separated by a blockage of these dimensions. Dr. Tyndall alleges that all the glens on the south side of Glen Spean were filled with ice, whilst those on the north side were filled with water. But so far from there being evidence of these valleys being filled with ice, it appears that they also were occupied by lakes, the traces of which are still visible in old beach lines, Even if there had been glaciers in Gleus Treig and N’Eoin, as suggested by Mr. Jameson, it would have been impossible for these glaciers to have protruded tongues long enough to have reached the places in Glens Roy and Collarig where barriers are required to have been. On High-level Terraces in Carron Valley, County of Linlithgow. By Davip Mityz-Home, LL.D. The river Carron runs into the Frith of Forth near Grangemouth. The princi- pal tributary is the Bonny. The whole of that district situated to the east of the Kilsyth and Gargunnoch hills is covered with deep beds of gravel and sand. The sand occurs in beds, mostly stratified and generally erizetta No marine fossils have been found in these drift-beds; but the great probability is that they are marine. The first set of terraces occur at a height of about 140 to 150 feet above the sea. Flats at that height occur on both sides of the valley some miles west of Falkirk; these flats slope towards the eastward, 7. e. towards the sea, so that near Grange- mouth they very little exceed 50 or 60 feet above the sea. Terraces at a height of from 140 to 150 feet occur also in the-upper parts of the Carse of Stirling. The second set of terraces occurs only along the banks of the rivers, and is at a height in the Carron of about 35 feet, and in the Bonny of about 29 feet above the present course of these rivers. It is presumable that these haughs were formed when the Carron ran in a channel about 27 feet above its present level, and when the Bonny ran about 25 feet above its present level. The formation of these haughs indicates that the rivers had run permanently in channels at that height. The sea therefore, in sinking, had paused in the process, and had stood at a height of about 24 or 25 feet above the present level. This inference is confirmed by the fact of there being traces of an old sea-beach at about that height visible along the coast of the Frith of Forth. The pebbles in the gravel-beds of the district are generally fragments of the hard porphyry rocks of the Gargunnoch and Kilsyth hills, situated to the westward, They could haye come from no other quarter. On the Bagshot Peat-Beds. By W.8. Mrrcnett, LL.B. On Cureinnate Vernation of Sphenopteris affinis from the Earliest Stage to Completion ; and on the Discovery of Staphylopteris, a Genus new to British Rocks. By C. W. Pxacn, A.L.S. The author stated that he had met with Sphenopteris affints in the Carboniferous “‘blaes” (shales) of an oil-shale pit at West Calder, near Edinburgh, in circinnate vernation, and with it a curious form, apparently a Staphylopteris (?), new to British rocks. Several species of this new genus have been found in Carboniferous rocks by the officers of the Geological Survey of [linois and Arkansas, in America; these are figured and described by Leo Lesquereux in the Geological Transactions of those States. The author stated that his differed from all these, and thus, until more is known about the British one, he had provisionally given it their generic name, a 4 - , t = YRANSACTIONS OF THE SECTIONS. 95 On the Mountain Limestone of the West Coast of Sumatra. By Dr. ¥. Rimmr. On the Raised Beach on the Cumberland Coast, between Whitehaven and Bow- ness. By KR. Russert, C.L., F.GS., and J. V. Hormes, .G.S., HAL Geological Survey, England and Wales. On the coast of Cumberland, between Workington and Bowness, the remains of an old sea-beach can be most distinctly followed, and south from the former place there is abundant evidence to show that the elevation of the land marked by this raised beach affected the whole of this portion of the west coast of Cumberland. The characteristic appearance which the raised beach presents is a flat of greater or less width stretching inland—in some cases terminating at the base of a cliff, and in other instances bounded by a flat from 4 to 5 feet below the level of the surface- gravel of this old beach. North of Workington we haye an example of the former case, and at Silloth an instance of the latter. The surface of this flat is covered with a number of ridges approximately parallel to the coast-line and to each other, and these ridges consist of sand and gravel par- tially covered at various places along the coast with blown sand. This ridgy ap- pearance is seen to be exactly like that portion of the present beach lying be- tween the levels of the highest spring- and the highest neap-tides, where small ridges of gravel are observed to be thrown up at the various ditterent levels to which the tide flows in the interval between the two periods above referred to. Typical examples characteristic of littoral"deposits are seen at Workington, Harrington, St. Bees, and at numerous places along the coast. The general resemblance between this upper terrace and the present beach, even in the absence of marine shells in the former, shows that the process of formation in both cases must have been the same. On the coast between Workington and Whitehaven it exists in small isolated patches, as at the north end of the ridge at Chapel Hill, at Harrington, at Parton, and at Whitehaven. From Workington northwards through Maryport to Brown Rigg the line of an old sea-cliffis for the most part very distinctly marked, at the base of which occurs a flat of from 40 chains to 2 chains in breadth ; at Allonby this flat is bounded by a gravel or shingle ridge; while from Silloth north to Grune _ Point, and across Morecambe Bay, from Anthorn to the Solway Viaduct, the country on the east of the old beach consists of a loamy plain, several feet below the level of this beach, from 3 to 4 miles broad, and dotted here and there with a few patches of sand and gravel. The height of the raised beach is from 20 to 26 feet, rarely exceeding 30 feet above the present sea-level. However the base of the old sea-cliff from Oyster Bank to Totter Gill, north of Workington, is about 40 feet above mean sea-level, and there is no distinctive cliff marking a 25-feet beach; it would therefore seem that after the first upheaval the elevation continued to take place very gradually until 40 feet was attained, the beginning of the period of elevation being indicated by the level of the land at the base of this cliff, and its close by the present sea-level. A consideration of the evidence to be obtained from Roman camps and other remains along the coast seems to confirm the conclusion arrived at by Mr. Milne- Home in regard to the latest elevation of the land on the Scotch coasts, viz. that it was prior to the Roman occupation of this country. Notes on the Drifts and Boulders of the upper pari of the Valley of the Wharfe, Yorkshire. By Rev. E. Stwett, M.A., F.GS., PRGA. It is evident that the Wharfe valley in many places must once haye been filled up to a certain height with gravelly drift and boulder-clays, containing a very large quantity of Millstone-grit blocks, and that since then the river has exca- yated a channel in the drift to the depth, im many places, of at least 150 feet, 96 REPORT—1876. Now if we suppose the pravelly drift to have been deposited by the river Wharfe, this must have taken place after the Glacial period, as it is clearly of newer date than the two boulder-clays. It would follow that the longitudinal slope of the river-course and other conditions must first have been favourable to deposition, and that afterwards the conditions changed, so as to enable the river to commence that process of denudation, or carrying away, which is still going on. While, however, it is somewhat difficult to conceive of postglacial changes so great as these, necessitated by this theory of the fluviatile origin of the gravels, we have no clear evidences of such changes having occurred since the final emer- gence of the land above the glacial sea. The rival theory that the grayels were deposited by the sea during the gradual rise in the land accounts for their pell-mell and varied character, and for the exis- tence of boulders lying at all angles. The latter may have been dropped from floating ice which may still have lingered on the surface of the sea. At a considerable elevation above the channels of the Aire and Wharfe, and where there is little or no clay or gravel, many angular and subangular boulders of limestone may be seen resting on Millstone-grit. They have chiefly been trans- ported from between the north and west, and in many instances they would appear to have crossed the intervening valleys and ridges. Mr. Mackintosh mentions two limestone erratics near the south-west corner of Embsay Moor, at an altitude of about 1100 feet above the sea. They may likewise be seen on Barden Moor, and a large number have been found at Barden Reservoir, about one mile south-west of Barden Tower. A few small fragments of limestone may be found resting on the Millstone-grit of Rombolds Moor, south of Ikley, at a height of at least 1100 feet above the sea. On the east side of the Wharfe valley, near “‘ Appletreewick,” there is a hill, consisting of Millstone-grit, called Symonds Seat (marked in the Ordnance Map Earls Seat). On the side of this hill limestone fragments, which must have come from the west or north-west, may be traced up to a height of 1200 feet above the sea, but not to a greater height, as I lately ascertained. At High Skyreholme, or Trollas Ghyll, about a mile to the north of this hill, are found a most interesting series of limestone-ravines, ranging east, north-east, and south-east, whose almost perpendicular sides rise 300 feet, their summits being not less than 150 yards distance from each other, 1200 feet above the level of the sea. On their rugged bottoms are scattered vast numbers of huge blocks of Mill- stone-grit in all directions. The whole of this district is, geologically, exceedingly interesting. The author believes it may now be regarded as a fact there are no erratics on the eastern slope of the north Pennine Hills in the district under notice at 4 greater height above the sea than 1200 feet. On the western slope it is well known that they haye reached a considerably greater altitude. On the Upper Silurian Rocks of Lesmahagow. By Dr. R. Simon. On the Age, Fauna, and Mode of Occurrence of the Phosphorite Deposits of the South of France. By J. H. Taytor, F.G.S. On Ridgy Structure in Coal, with Suggestions for accounting for its Origin. By Prof. Jamus Toomson, /.2.S.E. Further Illustrations of the Jointed Prismatic Structure in Basalts and other Igneous Rocks. By Prof. Jamus Toomsoy, F.R.S.Z. wishes TRANSACTIONS OF THE SECTIONS. 97 On certain pre-Carboniferous and Metamorphosed Trap-dykes and the Asso- ciated Rocks of North Mayo, Ireland. By Wiitram A. Trarry, M.A.L., E.RGSL., HM. Geological Survey of Ireland. The author first described the locality in North Mayo lying between Downpatrick os and Broad Haven, and referred to the geological map of Sir Richard riffith. The physical features presented precipitous coast sections at Keady Point 352 feet high, and at Benwee Head 829 feet high, in bold and perpendicular headlands. The geological formations comprising the older or metamorphicrocks lying to the westward consist of flaggy quartzites and micaceous schists, often much contorted and overlapped. The newer or Carboniferous rocks extending from the Glenglassera river eqstward, with a primary dip H.N.E. at low angles, comprise white, yellow, and red sandstones, with green and red shales, and limestone bands and beds further eastward. These Lower Carboniferous sandstones rest unconformably on the metamorphic rocks, which is best seen along one side of a fault at Fohernadeevaun, at the mouth of the Glenglassera river. The basal bed of the Carboniferous strata is a con- glomerate of from 1 to 4 feet in thickness, merging into the overlying sand- stone beds. With all due deference to the author of the geological map referred to, the presence of the band of Devonian rocks, as there represented, intermediate between the meta- morphic and Carboniferous rocks, was called in question and regarded as not existing in that locality. The intrusive igneous rocks of the district, though much resembling each other, and both belonging to the basaltic type, were shown to belong to two distinct epochs with regard to their time of formation, and also to possess characteristic distinctions. The older set are undoubtedly of pre-Carboniferous age, as unmistakable frag- ments are found in the basal congiomerate of the Carboniferous rocks, and they seem to have existed before and to have been metamorphosed with those beds among which they had been intruded. They largely penetrate the metamorphic rocks, but are not found within the area of the Carboniferous strata. They occur chiefly in sheet-like dykes up to 150 feet in thickness, and are often contorted with the beds they penetrate, though apparently the cause of some of the minor crump- lings. They are seldom hexagonal, spheroidal, or amygdaloidal in structure. As examples of these, specimens were exhibited and detailed descriptions given of dykes on Benmore and Glencalry, at Belderg Harbour, and Laghtmurragha, showing the effects of the metamorphic action upon them, viz. the change from a hard splintery microcrystalline basalt towards the centre, to a fibrous hornblendic schistose rock, with soft green chlorite and nests of green chloritic mica, the ex- terior becoming very schistose, platy, and micaceous, resembling a mica-schist; in part, these might be considered diabases. The felspar is plagioclastic and has a cha- racteristic white weathering in crystalline mottlings through the greenish base. The adventitious minerals frequently present are mica, chlorite, epidote, garnets, hornblende, quartz, calcite, varieties of felspar, and iron pyrites. The newer set, or post-Carboniferous dykes, are probably of Tertiary age, and seem to fill cracks or fissures or lines of faults. They are basalts mostly in vertical dykes, and always cut the sheet-like dykes, and are frequently hexagonal, sphe- roidal, or amygdaloidal in structure, and usually bear W.N.W. and H.S.E., and seldom exceed 25 feet in width. By their decomposing they separate many of the small islands from their respective headlands by narrow precipitous gullies, or form chasms into the cliffs: one of these clefts has vertical walls over 450 feet “high, and in part does not exceed some 10 feet in width; this same fissure also cuts off some four islands from their adjacent headlands, the view down which is almost unique. On the Sub- Wealden Exploration. By H. Writterr, F.G.S. 1876. 10 98 REPORT—1876. Recent Researches into the Organization of some of the Plants of the Coal- measures. By Professor W. C. Witttamson, F.RS. In bringing the subject before the Geological Section the author chiefly aimed at demonstrating the structural identity of Calamites and Calamodendron and of Lepidodendron and Sigillaria. The stems of Calamites described in his first memoir published in the ‘Philosophical Transactions’ were very young ones, in which the highly distinctive Calamitean organization was well preserved, and in one of which the vascular cylinder, composed of a ring of detached woody wedges, was enclosed in a thin parenchymatous undifferentiated bark. He now exhibited a series of specimens, beginning with one less than +; inch in diameter, in which the vas- cular cylinder was represented by little more than a circle of the canals, one of which is located at the inner angle of each vascular wedge, and in which the bark was thin undifferentiated parenchyma. From this starting point, the author passed through a series of intermediate examples up to one in which a large pith was sur- rounded by a cylinder of vessels having a circumference of 15 inches, and which in turn was enclosed within a bark 2 inches in thickness. The outer portions of the vascular cylinder had lost most of the special arrangements of its tissues so charac- teristic of young stems, which were now modified into a mass of thin radiating vas- cular wedges, separated by equally thin medullary rays, the condition being almost identical at the nodes and at the internodes. The bark also is now differentiated into two layers, an inner parenchyma and a thick outer prosenchyma, the cells of the latter assuming the prismatic type. There is little or no doubt that externally to this the living plant possessed at least a third layer of parenchyma not preserved in the author’s specimen. A series of sections was then exhibited, demonstrating the erroneousness of Brongniart’s distinction between Lepidodendron and Sigillaria. The author had previously pointed this out in the case of the Lepidodexdra chavacteristic of the lowermost Carboniferous rocks obtained from the Burntisland deposit.. He now showed that it was equally true of the common ZL. selaginoides of the Upper Coal- measures, whilst Z. harcourtw has only the structure long ago described by Brong- niart, viz. an inner vascular cylinder not developed exogenously. All the other Lepidodendra referred to possess an outer exogeuous cylinder such as Brongniart believed to be characteristic of Styillaria, and which exists in the Anubathra of Witham and the Diploxylon of Corda. The author thus concludes that the Lepi- dodendron harcourtu represents the lowest degree of development seen amongst the Lepidodendra, as Sigillaria exhibited the highest, whilst the Lepidodendren selagi- nodes of the Middle Coal-measures occupies an intermediate position, On the Junction of Granite and Old Red Sandstone at Corrie and Glen Sannox, Arran. By HK. A. Wtnscu, F.GS. The object of this paper is to show by specimens and diagrams that the rock intervening between the granite and the stratified rocks on the north-east coast of Arran is not, as held by Professor Ramsay and Dr. Bryce, a band of slate. There s no slate in all Glen Sannox, nor as far south as Brodick Castle. The sedimentary rocks, Old Red and Carboniferous, cropping upon the shore, retain in a remarkable manner the same general dip, the initial direction of which is given to them by the great anticlinal axis of mid Sannox, and abut right against the granitic nucleus of the island. As we approach the junction, at a height of about 800 feet from the sea-level, the angle of inclination becomes more highly inclined, and the hitherto clearly stratified beds assume a granitoid structure. At the point of contact the Old Red Sandstone is so altered as to resemble slate, and was mistaken for such and circumstantially mapped down as an extensive band of slate-by Dr. Bryce; but no one can mistake the real character of the rock if he begin his examination in the bed of the burn, about 60 yards below the junction, where the Old Red Sandstone is seen exposed in its unaltered state, fine- ——_. TRANSACTIONS OF THE SECTIONS. 99 grained and of the usual deep red colour, dipping S.E. at an angle of about 45°; and starting from this point the gradually altered character of the rock becomes ee every few yards as we proceed towards the junction. ‘The first appearance of change is shown in a series of chocolate-coloured rocks with greenish veins and streaks traversing them; and as these become more indu- rated they turn lighter in colour, and take on a beautifully mottled appearance, closely resembling variegated marble, and finally, within a few yards of the junc- tion, the rock turns dark grey or almost black. The actual contact is beautifully seen on the almost perpendicular face of the rock, under a waterfall formed by the small burn flowing over the lip of the Corrie south of the grand peak of Ciod-na- oigh, ‘identically the same appearances are observed when ascending up to the granite in the bed of the “ White Water,” the falls of which form a conspicuous landmark on the hillside above Corrie. The author made these two points typical, and his specimens and diagrams re- ferred to them; but numerous other sections are laid bare in the small burns and rayines intersecting the hillside, and bear out the same conclusions. The author showed a diagram from Corrie to the White Water, showing that if it were nut for the extensive denudation that has taken place we should probably see the Carboniferous rocks abutting against the granite, as they must originally have done. He also gave an enlarged copy of Dr. Bryce’s map of the localities referred to, accompanied by a duplicate map of the same localities and on the same scale, with the supposed slate replaced by the Old Red Sandstone. In Glen Sannox burn the junction appears to take place by contact of the granite with the massive Old Red conglomerate, and he was able to exhibit specimens quarried out of the bed of the burn showing large rounded quartz pebbles in a state of semifusion and the matrix of the rock traversed by alternate black bands and streaks and white semigranitic veins and patches; but though the actual junction must be within a few yards of the spot where he quarried, he was unable to lay it bare, owing to the deep water and the mass of gravel and sand in the bed of the burn. He also mentioned that everywhere at the point of contact with the Old Red Sandstone the granite is delicately mottled or clouded (as shown by his polished specimens), as if the black film of the absorbed mass had remained floating and become fixed in the white pasty mass. And this appearance he holds is in itself suflicient to point to a junction of granite with rock other than slate; for though innumerable instances may be seen in other parts of the island of junctions of granite with true slate, in not a single instance is the adjoining granite affected in this particular manner. On Siliceous Sponges from the Carboniferous Limestone near Glasgow. By Joun Youne, F.G.S. The author exhibited a series of mounted specimens of sponge-spicula re- cently obtained from a deposit of rotted limestone filling fissures in the Carbo- niferous Limestone series at Cunningham Bedland, near Dalry, Ayrshire. He stated that the discovery of the spicules was due to the investigation of the deposit by Mr. John Smith, of the Geological Society of Glasgow. He was not aware of similar sponge-spicules having been found in any other Carboniferous Limestone district within the British Isles, and their abundant occurrence in this deposit testified to the existence of sponges with large siliceous spicula over this tract of the Scottish Carboniferous sea-bottom. 100 REPORT—1876. BIOLOGY, Address by AuFrep Russex Watrace, F.R.G.S., P.L.S., President of the Section. Tuer range of subjects comprehended within this Section is so wide, and my own acquaintance with them so imperfect, that it is not in my power to lay before you any general outline of the recent progress of the biological sciences. Neither do I feel competent to ne you a summary of the present status of any one of the great divisions of our science, such as Anatomy, Physiology, Embryology, Histology, Classification, or Evolution—Philology, Ethnology, or Prehistoric Archzology ; but there are fortunately several outlying and more or less neglected subjects to which I have for some time had my attention directed, and which I hope will furnish matter for a few observations of some interest to biologists, and be at the same time not unintelligible to the less scientific members of the Association who may honour us with their presence, The subjects I first propose to consider have no general name, and are not easily grouped undera single descriptive heading; but they may be compared with that recent development of a sister science which has been termed Surface- geology or Earth-sculpture. In the older geological works we learnt much about strata, and rocks, and fossils, their superposition, contortions, chemical constitution, and affinities, with some general notions of how they were formed in the remote past; but we often came to the end of the volume no whit the wiser as to how and why the surface of the earth came to be so wonderfully and beauti- fully diversified; we were not told why some mountains are rounded and others precipitous ; why some valleys are wide and open, others narrow and rocky; why rivers so often pierce through mountain-chains; why mountain lakes are often so enormously deep; whence came the gravel, and drift, and erratic blocks so strangely spread over wide areas while totally absent from other areas equally extensive. So long as these questions were almost ignored, geology could hardly claim to be a complete science, because, while professing to explain how the crust of the earth came to be what it is, it gave no intelligible account of the varied phencmena presented by its surface. But of late years these surface-phenomena have been assiduously studied; the marvellous effects of denu- dation and glacial action in giving the final touches to the actual contour of the earth’s surface, and their relation to climatic changes and the antiquity of man, have been clearly traced, thus investing geology with a new aud popular interest, and at the same time elucidating many of the phenomena presented in the older formations. Now just as a surface-geology was required to complete that science, so a surface- biology was wanted to make the science of living things more complete and more generally interesting, by applying the results arrived at by special workers to the in- terpretation of those external and prominent features whose endless variety and beauty constitute the charm which attracts us to the contemplation or to the study of nature, The descriptive zoologist, for example, gives us the external characters of ani- mals; the anatomist studies their internal structure; the histolog:st makes known to us the nature of their component tissues; the embryologist patiently watches the progress of their development; the systematist groups them into classes and orders, families, genera, and species; while the field-naturalist studies for us their food and habits and general economy, But till quite recently none of these earnest students, nor all of them combined, could answer satisfactorily, or even attempted to answer, many of the simplest questions concerning the external characters and general relations of animals and plants. Why are flowers so wonderfully varied in form and colour? what causes the Arctic fox and the ptarmigan to turn white in winter ? why are there no elephants in America and no deer in Australia? why are closely allied species rarely found together? why are male animals so frequently bright-coloured ? why are extinct animals so often larger than those which are now living? what has led to the production of the gorgeous train of the peacock and of the two kinds of flower in the primrose? The solution of TRANSACTIONS OF THE SECTIONS. 101 these and a hundred other problems of like nature was rarely approached by the old method of study, or if approached was only the subject of vague speculation. It is to the illustrious author of the ‘Origin of Species’ that we are indebted for teaching us how to study nature as one great, compact, and beautifully adjusted system. Under the touch of his magic wand the countless isolated facts of internal and external structure of living things—their habits, their colours, their develop- ment, their distribution, their geological history,—all fell into their approximate laces; and although, from the intricacy of the subject and our very imperfect Paueladge of the facts themselves, much still remains uncertain, yet we can no longer doubt that even the minutest and most superficial peculiarities of animals and plants either, on the one hand, are or have been useful to them, or, on the other hand, have been developed under the influence of general laws, which we may one day understand to a much greater extent than we do at present. So great is the alteration effected in our comprehension of nature by the study of variation, inheritance, cross-breeding, competition, distribution, protection, and selection—showing, as they often do, the meaning of the most obscure phenomena and the mutual dependence of the most widely-separated organisms—that it can only be fitly compared with the analogous alteration produced in our conception of the universe by Newton’s grand discovery of the law of gravitation. 1 kmow it will be said (and is said) that Darwin is too highly rated, that some of his theories are wholly and others partially erroneous, and that he often builds a vast superstructure on a very uncertain basis of doubtfully interpreted facts. Now, even admitting this criticism to be well founded—and I myself believe that to a limited extent it is so—I nevertheless maintain that Darwin is not and cannot be too highly rated ; for his greatness does not at all depend upon his being infallible, but on his having developed, with rare patience and judgment, a new system of observation and study, guided by certain general principles which are almost as simple as gravitation and as wide-reaching in their effects. Andif other principles should hereafter be discovered, or if it be proved that some of his subsidiary theories are wholly or partially erroneous, this very discovery can only be made by following in Darwin’s steps, by adopting the method of research which he has taught us, and by largely using the rich stores of material which he has collected. The ‘Origin of Species, ’ and the grand series of works which have succeeded it, have revolu- tionized the study of biology: they have given us new ideas and fertile principles; they have infused life and vigour into our science, and have opened up hitherto unthought-of lines of research on which hundreds of eager students are now la- bouring. Whatever modifications some of his theories may require, Darwin must none the less be looked up to as the founder of philosophical biology. As a small contribution to this great subject, I propose now to call your atten- tion to some curious relations of organisms to their environment, which seem to me worthy of more systematic study than has hitherto been given them. ‘The points I shall more especialy deal with are—the influence of locality, or of some unknown local causes, in determining the colours of insects, and, to a less extent, of birds; and the way in which certain peculiarities in the distribution of plants may have been brought about by their dependence on insects. The latter part of my address will deal with the present state of our knowledge as to the antiquity and early his- tory of mankind. On some Relations of Living Things to their Environment. Of all the external characters of animals, the most beautiful, the most varied, and the most generally attractive are the brilliant colours and strange yet often elegant markings with which so many of them are adorned. Yet of all characters this is the most difficult to bring under the laws of utility or of physical connexion, Mr. Darwin—as you are well aware—has shown how wide is the influence of sex on the intensity of coloration; and he has been led to the conclusion that active or voluntary sexual selection is one of the chief causes, if not the chief cause, of all the variety and beauty of colour we see among the higher animals. This is one of the points on which there is much divergence of opinion even among the sup- porters of Mr. Darwin, and one as to which I myself differ from him. I have argued, and still believe, that the need of protection is a far more efficient cause of 13876. “102 REPORT—1876. variation of colour than is generally suspected ; but there are evidently other causes at work, and one of these seems to be an influence depending strictly on locality, whose nature we cannot yet understand, but whose effects are everywhere to be seen when carefully searched for. Although the careful experiments of Sir John Lubbock have shown that insects can distinguish colours—as might have been inferred from the brilliant colours of the flowers which are such an attraction to them—yet we can hardly believe that their appreciation and love of distinctive colours is so refined as to guide and regu- Jate their most powerful instinct—that of reproduction. We are therefore led to seek some other cause for the varied colours that prevail among insects; and as this variety is most conspicuous among butterflies—a group perhaps better known than any other—it offers the best means of studying the subject. The variety of colour and marking among these insects is something marvellous. There are probably about ten thousand different kinds of butterflies now known, and about half of these are so distinct in colour and marking that they can be readily distinguished by this means alone. Almost every conceivable tint and pattern is represented, and the hues are often of such intense brilliance and purity as can be equalled by neither birds nor flowers. Any help to a comprehension of the causes which may have conewred in bring- ing about so much diversity and beauty must be of value; and this is my excuse for laying before you the more important cases I have met with of a connexion between colour and locality. Our first example is from tropical Africa, where we find two unrelated groups of butterflies belonging to two very distinct families (Nymphalide and Papilionide) characterized by a prevailing blue-green colour not found in any other continent *, Again, we have a group of African Pieridae which are white or pale yellow with a marginal row of bead-hke black spots ; and in the same country one of the Lyczenide (Leptena erastus) is coloured so exactly like these that it was at first described as a species of Pieris. None of these four groups are known to be in any way speci- ally protected, so that the resemblance cannot be due to protective mimicry. In South America we have far more striking cases; for in the three subfamilies Danaine, Acreine, and Heliconiine, all of which are specially protected, we find identical tints and patterns reproduced, often in the greatest detail, each peculiar type of coloration being characteristic of distinct geographical subdivisions of the continent. Nine very distinct genera are implicated in these parallel changes— Lycorea, Ceratinia, Mechanitis, Ithomia, Melinea, Tithorea, Acrea, Heliconius, and Lueides, groups of three or four (or even five) of them appearing together in the same livery in one district, while in an adjoining district most or all of them undergo a simultaneous change of coloration or of marking. Thus in the genera Ithomia, Mechanitis, and Heliconius we have species with yellow apical spots in Guiana, all represented by allied species with white apical spots in South Brazil. In Mecha- nitis, Melinea, and Heliconius, and sometimes in Tithorea, the species of the Southern Andes (Bolivia and Peru) are characterized by an orange and black livery, while those of the Northern Andes (New Granada) are almost always orange-yellow and black. Other changes of a like nature, which it would be tedious to enumerate, but which are very. striking when specimens are examined, occur in species of the same groups inhabiting these same localities, as well as Central America and the Antilles. The resemblance thus produced between widely different insects is some- times general, but often so close and minute that only a critical examination of structure can detect the difference between them. Yet this can hardly be true mimicry, because all are alike protected by the nauseous secretion which renders them unpalatable to birds. In another series of genera (Catagramma, Callithea, and Agrias), all belonging to the Nymphalidx, we have the most vivid blue ground, with broad bands of orange- crimson or a different tint of blue or purple, exactly reproduced in corresponding, yet unrelated species, occurring in the same locality; yet, as none of these groups are protected, this can hardly be true mimicry. A few species of two other genera * Romaleosoma and Euryphene (Nymphalide), Papilio zalmoxis and several species of the Nireus-group (Papilionide), SERN = TRANSACTIONS OF THE SECTIONS. 103 in the same country (Zunica and Siderone) also reproduce the same colours, but with only a general resemblance in the marking. Yet, again, in Tropical America we have species of Apatura which, sometimes in both sexes, sometimes in the female only, exactly imitate the peculiar markings of another genus (Jeterochroa) confined to America : here, again, neither genus is protected, and the similarity must be due to unknown local causes. But it is among islands that we find some of the most striking examples of the influence of locality on colour, generally in the direction of paler, but sometimes of darker and more brilliant hues, and often accompanied by an unusual increase of size. Thus in the Moluccas and New Guinea we have several Papilios (P. euchenor, P. ormenus, and P. tydeus) distinguished from their allies by a much paler colour, especially in the females, which are almost white. Many species of Danais (forming the subgenus Ideopsis) are also very pale. But the most curious are the Huploeas, which in the larger islands are usually of rich dark colours, while in the small islands of Banda, Ké, and Matabello at least three species not nearly related to each other (L£. hoppfert, E. euripon, and £. assimilata) are all broadly banded or suffused with white, their allies in the larger islands being all very much darker. Again, in the genus Diadema, belonging to a distinct family, three species from the small Aru and Ké islands (D. deots, D. hewitsonti, and D. polymena) are all more conspicuously white-marked than their representatives in the larger islands. In the beautiful genus Cethosia, a species from the small island of Waigiou (C. eyrene) is the whitest of the genus. Prothoé is represented by a blue species in the continental island of Java, while those inhabiting the ancient insular groups of the Moluccas and New Guinea are all pale yellow or white. The genus Drusilla, almost confined to these islands, comprises many species which are all very pale; while in the small island of Waigiou is found a very distinct genus, Hyantis, which, though differing completely in the neuration of the wings, has exactly the same pale colours and large ocellated spots as Drusilla. Equally remarkable is the fact that the small island of Amboina produces larger-sized butterflies than any of the larger islands which surround it. This is the case with at least a dozen butterflies belonging to many distinct genera*, so that it is impossible to attribute it to other than some local influence. In Celebes, as I have elsewhere pointed out +, we have a peculiar form of wing and much larger size running through a whole series of distinct butterflies; and this seems to take the place of any speciality in colour. From the Fiji Islands we have comparatively few butterflies; but there are several species of Diadema of unusually pale colours, some almost white. The Philippine Islands seem to have the peculiarity of developing metallic colours. We find there at least three species of Zupleat not closely related, and all of more intense metallic lustre than their allies in other islands. Here also we have one of the large yellow Ornithoptere (O. magellanus), whose hind wings glow with an intense opaline lustre not found in any other species of the entire group; and an Adohias§ is larger and of more brilliant metallic colouring than any other species in the archipelago. In these islands also we find the extensive and wonderful genus of weevils (Pachyrhynchus), which in their brilliant metallic colouring eg any thing found in the whole eastern hemisphere, if not in the whole world. In the Andaman Islands in the Bay of Bengal there are a considerable number of peculiar species of butterflies differing slightly from those on the continent, and generally in the direction of paler or more conspicuous colouring. 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