A eA Oh et . . ry dete Ot bk rie 48 PE RE Us Bene a AD Sean Se HN BeOS +4 A Maiyah ar His Pete ane as Me ere A aE te lee tee ace lt Ede tm Ages Weeie i ee ea Vandsha sighs ook a Gent ott Hot ¢ ¢ We ete a “Hee el ett See ote hea Ce Ms Fees ker a tke heir ewe rl SR ee erin ale Mente Wee 4a gots ettrdt are gh 4 AU ACM He thet thet blip cg “ e ‘ Ly sane ok ama tsttew: nah Is pare mee arty rattan ey bids rena emis ite 9 are ‘ by he Wh Mh ty Went bg hath the tht ate ‘een tie 3 Miche tedees Bert ah (sth tan 9 Oe Carts Be of ! ute erate teas ane i beAchgh dharha it ws ioe Wee em the 4 esate? a sitecateron hcg as a7 se hate AR nis the AP tS ww Hs Mh A Seen Fe aE Aa Oh Wate EM 1 Oe A Ri Sa AY sitet tah ie fea eae Se gree eh HAL WoW COW i deth BR M ao HF ay whee aera doy dee, Fy baa Seay Wie a FAT Mon ed nme Hh OTN GRATE T-tiatoms ak WIE OF Wale teoe Mae, Ceaea " Ne ante GA A aot Geek OW we nim tle Ge Hath ¢ Lae Bi Setar tia aaa ri Maen « Med atk ek He ee ed ee NEN ST Me ; Ame tee PTI e ek oe ot heh 2 tee 4 Mek Hw ikey don eal are RM Sack Pcrtaeec Air ae fete ot ort Nate eie ie eked to ot 48 te bg 0 wt EM tedeh «here © Kas reas +4 sis Ltt ee he fi te Hy eee tb ati: Sotosiewoaatt: € Ant Matte Me 4am hese ey ie a on WT Ai eit err i te Ay cen 4det Hoth ted (ket de the ee ets. ch Oe Gee a hrtioke ah fla Ce ee sana eit te ee Lyte ks Pha Seni A aeA Gotta is hie a : ea he Ae & VG ei Oo eh 4 Use et AE, Geil wed ie bs He a er th AE hear tt tote AoW erik. 4 (beech toda o 24 eee tee ae ie lahat a a am ora a oR go a TRO I SCM Lie SLs a tat ed ATs anthems ede tM, n phanbuticsty MOM eee MCW Geet Ae Ee Be IE Ain Se a OE ABE OM chat Use a: ths hs Nitrate ais hi 4 : chp tin owed ato Hot, asenagh » ee Pe ee ae tye «he oats BOE . oa : tara-yed Wonca ara: 4 Eee ORLA He )4 ae eee Aaa? ‘oe Va ae hed ibaet Heg tee by ewer'y Caen eet mee en neh 1%, Hue 4h oy aA anat eae a Petes odie yA re Wah tet eee we ee ee ee eet eee Coe ee EB eg Pe EIS UC RCS SC Mache ALL Nab ath ee Pert yd aii aot Wt B48 Ke er eC ee ee ae BA Lee Sak ee aS Pisin ais oa ee it Ch Oe denn We rb Hd on Ae Meee eae Ty fe Ge Walk Gate ea Oe th Go nek ge ee Hage HN eth Ob he a he ad og ah deeds We HE held ee hy aired : As AE 8 MD EN A Meat ot Rese eae eae Watts eth wtoishy ke Feed host een dete ft s Ts: ie ths wih HA del Wits tact ret ea ipa th 4a ele CD a ee ge, ‘ FAM Oo Aen oh thet Littell? PA ee ee rade a dein ee 2 at ak ek et i, elke Het TUNA te ea A ete ee ee) ED ae endcd a o 1 a EE tet GE ite Oe do teetemete tales be nity, us eter ede i aceon ok Ur Ay « WN BAe ts Pres. ‘ A SERN MH Kt ne Pee it Ta gat. dete orks 4 p see tah A nea tn eee Beye a a ho : ‘ ; apie ihrnults a hee é wets . 4 eed Bot Rot aa Cae Yeh ba ake: AY Sot Nash aoek ran a sy ps) c ae > Tee avers Wa Aas Hea toaraY oe 0 ow ed ae dal Bru dete ale ‘i he as ek he Rote f= Ge LM WY UE Ra qett ete eA Bie Wee ae OS ae aoe ery a Pee she cha orate ded 13 % fast ye , a) rm * Pies Pah Sy earn Cabanon aa a et He ede ay i ow ae ed Sot Ree Ag edad = : idle ee ae a he AME ek Lite de Be ro Sedat ge aeteay eed ergn oe Ae te gg eae oeeganeaeie Fy Saath oH We lige i) " 4 a ind Anidonbik alae hia ah youn Saele asa #4 " o eaet gage Ly a eet ae Neues Hy) eo ‘i bas rtet Hs a ee hia we hh, Ba Vee 9 in q url Wty oN @ ASRS <0 Went Cae a Lg ft oe Ht eh ae a, a oie sak ae “ A Ath 4 " ye ee i‘ Se carder da wy La deme Acq iae ean re Cee AN ATA aM ES He de: q i bis Oy (ba it? one : il aa ba eas 3 aa whee de dod fC TAAL AS et! PM. Fi cha cas Mn, et 4-4 seu ith oe eet eg 8 A retedin that te oat eo 3 ee ee | (ine fe ae 3 “Ge ee le eae) 8 4 qe wes 4 Bye it Yea BS GB 0 hs dh Grit ii ihe i ee aie | Ral sged! ‘les et ge Ba he pty i renee eae oe Hehe AE AS ete ed Mei: See eee eb e I Eee re aCe ha Wh eA ike et ine Het kek a ete fae Uh me erp a ME EGY A ‘ a Vey uy 4 Tie ted ta moss Eki eit Ais irae mei Estee » Pe Atta vias UN ey hath SLES. ah Ne ee cee ae Bee ale 4 hy z pene te Bans ba “ay ait " eh we 18 Oo aE if at ea G8 ae: Grit Gane a estat vate ite +4 DRA ua fh so aces eae ice ced UT ab We PR a inp sd deta & ¢ se dedait Tea goed rie gaged aot gM ek Cee alate AOE EA ST NITE pet at AG EU A Wee ee wether (8 hs He oh ye teh tt viet Apatite SEE EVEN PMA HOC NS Cee B me AA Hae oY ‘* Pept Wa Met Bey Abe ew ae 4 Ee eg mi pe A at) Ra RAT AA it a a ee A LM Si ak ede WEE dete yall ety Et ME Ae a ee gE + antes bee » EkaiAL. Ys be 4 ire - “age 44 ew id heey Ae oe eet a to Rew e t Un et Re Ks + Caves dart Shah ns “ae Ce ee oe ted Gate a. eo AN ; he wie ho aia nee) Wolk a a thy yon fiw ie had! NM We eth We WE EAL het co % ; “i Vee We oni if Paley triers eens WEAN WS the ted hate Eatery See rate Ye “ee ¢ A ete epee © EEN EHEC Ha UH OA Dee He 9 Led ® Pye eek ee one dee Hee ed HOT Wash We es Ueda thet er ALG Tee a8 aidewe ane HH Ge 4 ACRE AA Ge WT MO ee RRO Ui eM nthe dete katte. ek Ao ew aie Wee We tate ge Aer are tira Rees het Me tacart, oh fee’ ee foe Pvemeeraeonn 7 Hah e0n. « a Ae AE A ey HOW Hat 4 eed A eed MEd 2 STAG AN HVA Nd Wd B Pali Pee Om + Wet 4 ih eet Rapti. Oe ee Rede a a tod ee ers heated PV Ged eb athe AP tte tv Met ek dead et THEE He CE ad rn anh Was tae Wt + GAPenihe HOM fi drtet aS Aon Ny Ye WW ie Lf al fee PEK Ha ot *teg he ey PES Ban her A Ait Raia Sk ott: heheh ety Perera er) mat eth ee a th fae me Aw Ae ae OCIA Kats ee Geb teers rN ts ee a es col see Hanne! “ang sip aon 1 et HOW EG TW Wracauase Mee) Gan MATE ant ep APA ea ty pie rere be tte te CeO CO ek ee a MW ASO RSA HoH etree 65 Mie ra ae Wat WORM tek He ee ie RT 5 ee ee Wyre ie We the yardage Sha dee Ook ea Wca: WoW a Sark ek WE hs eh eee eg i ar ean oC oe bangle Dh be enn R Tr WHT Ric OPIN BCE URE ive tat ath woagnat Rete PSH Mth eR « Ae RA ed eye Cie FOE AE HWS * uy Cea Cord a FH ee be at Ge geek a be Cty eee AE Od - Mey MH A BH ete de Het dette Gi by ded leet Wee . HWE A oN Ob ate wid eee eee eee ee H = Wat Het Re wud Ot aa a FEW Heda tea ales Howe y F aa ot eld Hatheig Aah Wee Wares tere Crk ew Awe W) eyo Ha tS HEHE HD CARMA HAM! cs HREOC R et re ek ce be ett Wa yfene ashe a Mn WAY: Saye wee wrws arb Aa 1A 9 dog a RR le ake Wry 8844 boa le i MT RW eRe ded He Heth! try Wet te HH Ear a cod fie ed TF meats i 248 Ro eH Od He a He Mele Oe TOF PAE Ste Ee Se PAPE MATa BP Dad) j : a en wes wh oe ae a ee ee re | pipette de he 4 a i RR woth uae te lie de earn Nate rh G cus Rae AAO Hee eh Oe Fe Oa He eed us sata i A re Ww ed Ceara “aan niga twee a Sivoo ag Mash area a MAG Mod we neOs HeR ‘ got iY ak ss ‘ ne voy Slee PEN Cette EN are het arden yy PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. From January 6, 1887, to June 16, 1887. Gl SLIE Boras ———— pera A 7 can ieee oe AIS OI VUlY GP pm ™~ VN WkoN / \ VoO\ a \ \ i \ DP / bn Ty 5 : rif ay : ON UA hs -pO?y ee SON IA N DEP on Dre A a LONDON: HARRISON AND SONS, ST. MARTIN’S LANE, Printers in Ordinary to Her Majesty. MDCCCLXXXVII. LONDON: HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE. CONTENTS. VOL. XLII. —-+8 263" — No. 251.—January 6, 1887. lage On the Occurrence of Silver in Volcanic Ash from the Eruption of Cotopaxi of July 22nd and 28rd, 1885. By J. W. Mallet, M.D., F.R.S., University of Virginia Preliminary Note on the Continuity of the Liquid and Gaseous States of Matter. By William Ramsay, Ph.D., and Sydney Young, D.Se............. 3 Note on Lepidodendron Harcourt and L. fuliginosum, Will. By W. C. Williamson, LL.D., F.R.S., Professor of Botany in the Owens College and in the Victoria University U Uivavadsncnsna Hocpsentranstrsuasener a ceatccumGeassae casein 6 On the Organisation of the Fossil Plants of the Coal-measures : Heteran- gium Tilieoides, Will, and Kaloxylon Hookeri. By Professor W. C. Williamson, i Dek: R. S., Professor of Botany in the Owens ne and in the Victeria University Rn aera ecto er tras wiccnseeemerest coger tenet sacdsMeeacemeens 8 MSG OE EVESCUIUS......1.r0nscesenersceoes eben Nien) een aa oe Alaa LO January 13, 18877. Supplementary Note on Polacanthus Foxit, describing the Dorsal and some parts of the Endoskeleton imperfectly known in 1881. By J. W. Beet MU lege Pe Ech y MMa e ode c 005, Rule 3a one olctinbds wifes elie see done uoudecena tan aomensdeisemetinisker eres 16 The Reputed Suicide of Scorpions. By Alfred G. Bourne, D.Sc., Fellow of University College, London, and Professor of Biology in the enesiemey, Colilemed Magia sel op. s cicero. \evintliasieecaats decderusdedl chedsde abate eensoos tebe Ly Supplementary Note on the Values of the Napierian Logarithms of 2, 3, 5, 7, and 10, and of the Modulus of Common Logarithms. By Pro- fessor J. C. ‘Adams, EVIE Se BMEUAS tae) satya dens aenioma ieee cge. eae C ge, Meum: 22, On the Crimson Line of Phosphorescent Alumina. By William Crookes, LIE SEN VT GLE cE SMM ieee nae oN eet 2am pe a eg Oye OR 25 List of Presents January 20, 1887. Some Anomalies in the Winds of Northern India, and their Relation to the Distribution of Barometric Pressure. By S. A. Hill, B.Sc, me Reporter to Government, North-Western Provinces and u Page Savtsueawaganadiausubees vevenedacuog ieopatp anu poeeparecceter adtetebery came at aalts et eee a 35 Evaporation and Dissociation. Part V. A Study of the Thermal Pre- perties of Methyl Alcohol. By William Ramsay, Ph.D., and Sydney Biaonnres MSG." 4 Se. roe eeene. Mencrn me eee na sidnounp aves soeecaceoecsnatant tse eee 37 Further Discussion of the Sun-Spot Observations made at South Kensing- ton, By J. Norman Lockyer, WAS. 3.63020... 37 PUISt OF WESC tS |.c.ceseeseenasses ace issasuper cal oavedpsonvdnedhensdeens phases se ee AT January 27, 1887. On a Perspective Microscope. By George J. Burch ..........:ccccscusecsssceseceveseve =) On the Thermodynamic Properties of Substances whose Intrinsic Equation is a Linear Function of the Pressure and Temperature. By Geo, Fras. Fitzgerald, M.A., FLR.S. «1.0... faiing siva dibantGi euseie>aasuadeaennet cine er 50 On the Morphology of Birds. By W: K. Parker, FURS, ....:..c.nscsae seo WMISt Of PHESENES ......-.¢ecsesseearesnecenrse: otuapnenpuaiece seth cape sue sane lebese eer 59 On the Computation of the Harmonic Components of a Series representing a Phenomenon recurring in Daily and Yearly Periods. By Lieut.- General R. Strachey, RW.) BRS 2 ccice vcenccoseespeseeceeteeeperaseseet stan ea 61 No. 252.—February 3, 1887. On the Waves produced by a Single Impulse in Water of any Depth, or in a Dispersive Medium. By Sir W. Thomson, Knt., LL.D., F.B.S..... 80 On the Formation of Coreless Vortices by the Motion of a Solid through an inviscid incompressible Fluid. By Sir W. Thomson, Knt., LL.D., On Protorosaurus Spenert (von Meyer). By H. G. Seeley, F.R.S., Pro- fessor of Geography in King’s College, luondom. ......,-....,..0:.2.:0:seeeeee 86 Mish ot Presents br). cph. covreeiel. Ud dibtroe alg mathntaeaseepeaeeiaenieel om wise 8B February 10, 1887. Contributions. to the Metallurgy of Bismuth. By Edward Matthey, RSA. F.C.S.,..Assoc. oy, ch. Manes! issc....:c2esscoyeres0ctonss ene 89 An Inquiry into the Cause and Extent of a special Colour-Relation between certain exposed Lepidopterous Pupz and the Surfaces which immediately surround them. By Edward B. Poulton, M.A., of Jesus and Keble Colleges, Oxford, Lecturer in Zoology and Comparative Anatomy at St. Mary’s Hospital, Paddington .........cscteetessesseessnesesececesens g4 MENS oiot E PESOS ¢o25 Fe ce ssideec pen vocsseessvdeunarinone iacudvea'les Ua tate delnestns rites cc' ies Core tte 109 February 17, 1887. Page A Record of Experiments upon the Functions of the Cerebral Cortex. By Victor Horsley, M.B., F.R.C.S., F.R.S., Professor Superintendent of the Brown Institution, and Edward Albert Schafer, F.R.S., Jodrell Professor of Physiology in University College, London. (From the Physiological Laboratory of University College).........ccccscescsseseeeeeseeeeecee 111 On Radiant Matter Spectroscopy :—Examination of the Residual Glow. Peace rookes, FURS FV B.C8 5 os cass liccdasccnssne dan oancevncdinnantendeases inne 111 ae BEERS SR Sh Be ye fae ea gat Was cen adc ncous cee Pusana sedtanadednase Wearere 131 February 24, 1887. Problems in Mechanism regarding Trains of Pulleys and Drums of Least Weight for a given Velocity Ratio. By Henry Hennessy, F.R.S., Professor of Applied Mathematics and Mechanism in the Royal College Pf Sotemp ne, JUS RO eae) Aer ere th seer Mn oe i ae nk ee unnDEe” URNA 134 On the Relation between Tropical and Extra-tropical Cyclones. By Hon. Serpe nee cron by.) BE. MEbS SOG. .ccgl ec cessscte seus tes ceucsensuseasvacenoe duvsenes 138 A Thermal Telephone Transmitter. By Professor George Forbes ........... 141 CLS EE LE LES ETSTTS oe cor er gg IR i EA nN ee ca Se aT a 142 ie SORIA PRTC E ND AOS se gc oe cine Leuas dcoxgstn dl sew eteo wi da sehasohton cal ace nas Rea Ren nee 145 Preliminary Note on a Balanoglossus Larva from the Bahamas. By W. F. R. Weldon, M.A., Fellow of St. John’s College, Cambridge................ 146 Studies of some New Micro-organisms obtained from Air. By G. C. Frankland, and Percy F. Frankland, Ph.D., B.Sc. (Lond.), F.C.S., SER Oe UE GEE oto L 120.5 dg ds aah Savona Seoeacbaebedtonnadilacdtathsseweydteenamecrrees 150 On the Limiting Distance of Speech by Telephone. By William Henry Piper Race ae soe, eee ee cece eee ke Ee ocean d Vans Seo Nata cebu tea cea a ekatess SM 152 The Etiology of Scarlet Fever. By E. Klein, M.D., F.R.S., Lecturer on General Anatomy and Physiology at the Medical School of St. Pee OMe SN EVOSpital, LOMO, ...0).c.c-c cee ce.sesdee~sencensossbsnadnsedentsesesesnceteoone 158 MT PTIMEESECCIN GRE ean eran Ae ER eR ed A ad eae Se ea a 161 March 10, 1887. Note on Induction Coils or “Transformers.” By John Hopkinson, M.A., Se. BAS: scsi MARA csM eden cs Veeec tones suntsauls sess lssvaatudenbneeelaniuesdeaasetcchim saepdes 164 Note on the Theory of the iterate Current pene: a John Hoplomsom EA... D.Sc. BRS.ik ces ate tear LOn Transmission of Sunlight ae the Earth’s Atmosphere. By Captain W. de W. Abney, R.E., F.R.S.. ........... Re ne Ae) Mist OF PTeESeNtS soi cieiciccsccsscce Wt ae sepa A ae ek ek abso, Peels sas ei Sd a eal bee YO 72 ‘al March 17, 1887. A Coal-dust Explosion. By W. Galloway ............ schananstesssces +240 147 ea 174 Second Note on the Geometrical Construction of the Cell of the Honey Bee (‘ Roy. Soc. Proce.,’ vol. 39, p. 253, and vol. 41, p. 442). By Prof. H.. Hennessy, FURS... iss UA 176 The Embryology of Monotremata and Marsupialia. Part I. By W. H. Caldwell, M.A., Fellow of Gonville and Caius College, Cam- HONE soso acca eke soesicedd cen cusch evnuibyjn sPadyate ved canta ees Seba cu cae ene ecco eer rr 177 On the Total Solar Eclipse of August 29, 1886 (Preliminary Account). By Arthur Schuster, WlBS......c..cccccesecessseon-saunceeece (cee easdas0 sented 180 Mist ot HPresemts, 6.6). acc BA APNG Sieh tials Ch aca ae, sescurseetdeue eae 182 Contributions to the ayy of Chlorophyll. No. II. By Edward Schunck,, PRS. (Plate 1) cic f i We okies rset cones ced toate er 184 March 24, 1887. _ Preliminary Note on the “Radio-micrometer,” a New Instrument for measuring the most Feeble Radiation. By CY. ae Demonstrator of Physics at the Science Schools, South Kensington.... ee 1 Oo N ote to a Memoir on the Theory of Mathematical Form a Phil. Trans.,’ 1886 (vol. 177), p. 1): By A. BYKempe,; MEA. E.R S_..c ee eee 193 On Ellipsoidal Current Sheets.- By Horace Lamb, M.A., F.R.S., Pro- fessor of Pure Mathematics in the Owens College, Victoria Uni- WELSIDY 0.05: agen Segripdonnadovouaanias Mead boastobalealee: Ae. meanness ae kkk 196 On the Magnetisation of Iron in Strong Fields. By Professor J. A. Ewing, B.Sc., F.R.S.E., University College, Dundee, and Mr. William WOW TALS 2). civesclics cass ceienseundec cuevaesrd ies cee evtgasoueuetenscsyeutae-se.. 12) tee earn 200 Wistiot Presents: 454.28 ae dadvehch wd teenie MAS 210 March 31, 1887. Note on the Development of Voltaic Electricity by Atmospheric Oxida- tion. By C. R. Alder Wright, D.Sc., F.R.S., Lecturer on Chemistry and Physics, and C. Thompson, F.C. S., Demonstrator of Chemistry, in St. Mary’s Hospital Medical S@hool .........c0.sci0.-.c000 10:++c00s0s0ss00 cee ee 212 Clausius’s Formula for the Change of State from Liquid to Gas applied to Messrs. Ramsay and Young's Observations on Alcohol. By Geo. Fras. Fitzgerald, M.A., F.T.C.D., F.R.S., Erasmus Smith’s Professor of Natural and Experimental ’ Philosophy in the University of Dublin +4... saree dsdasMicast dvd eireemenantreeeessats ces ager baitadah race Wn mentees een cr 216 The Influence of Stress and Strain on the Physical Properties of Matter. Part III. Magnetic Induction. By Herbert Tomlinson, B.A. ............ 224 Note on a New Constituent of Blood Serum. By L. C. Wooldridge, M.D., D.Sc., Research Scholar to the Grocers’ Company Vil Ee liuincery Note on the Fossil Remains of a Chelonian Reptile, Cerato- chelys sthenurus, from Lord Howe's Island, Australia. a ys Thomas H. Huxley, FBS. esis Sects vache pee nC Meee Action of Caffein and Theine upon Voluntary Muscle. Sai T. Lauder Brunton, M.D., F.R.S., and J. Theodore Cash, M.D.. Ne Contributions to our Knowledge of the Connexion between Chemical Constitution and Physiological Action. Preliminary Communication on the Action of certain Aromatic Bodies. T. Lauder Brunton, M.D., F.R.S., and J. Theodore Cash, M.D. . List of Presents... On the Effect of Polish on the Reflexion of Light from the Surface of Iceland Spar. By C. Spurge, B.A., St. Catherine’s College, Cambridge No. 254. Further Experiments on the Distribution of Micro-Organisms in Air (by Hesse’s method). By Percy F. Frankland, Ph.D., B.Sc, F.C.S., and rmbt nee OSE SM (PN AGE: Bh)! cc. nsses evenness aceveecdapste aceerdgacontnecystnazenscaagess April 21, 1887. On Phosphonium Chloride. By Sidney Skinner, B.A., Scholar of Christ’s Page eye” .. 238 .. 240 .. 240 242 267 Pp RO TELE EVO Cer eco cc sds Secu dedecan tte cnoanaahnvs avenceeeieh vous sonuteeseneseeat 28: On the Principal Electric Time-constant of a Circular Disk. By Horace Lamb, M.A., F.R.S., Professor of Pure Mathematics in the Owens eM Fee OM et WO IVIVCTSILY. si. ococadSteadeine. seede cud sine , Norman Evans... cet testessaticervan paiaih asupat 379 Note on the Electrodeposition of Alloys and on the Electromotive Forces of Metals in Cyanide Solutions. By Silvanus P. Thompson, DBC MEANY, Suis ke, cusaesvsceshotachyanestibbarterbsitastease douelics thos usousurytyrteneansny atuusysndei ste pusgs 387 On the true Fructification of the Carboniferous Calamites. By William Crawford Williamson, LL.D., F.R.S., Professor of Botany in the Owens Colleséetamd the Victoria University ii. horas Ale ed ie Aa Radi ve 389 On Fossil Remains of Lchidna Ramsayi (Ow.). Part II. By Sir Richard Owen, K.C.B., F.R.S., &c. x Page Description of anewly-excluded Young of the Ornithorhynchus paradozus. By Sir Richard Owen, K.C._B., URIS., G66. ....cc+..ccsaseossee onde 391 On the Nephridia and “ Liver” of Patella vulgata. By A. B. Griffiths, Ph.D., F.R.S. (Edin.), F.C.S. (Lond. and Paris), Principal and Lecturer on Chemistry and Biology, School of Science, Lincoln ............ ee ceseeeceeoee 392 The Air of Sewers. By Professor eae Nas, 3 D.Sc., and J. S. ee M.A., M.B., University College, Dundee .. sie . 394 On the ee of Water el. Volume. sees Alexander Scott, M.A., On Muscle Plasma. By W. D. Halliburton, M.D., B. go Assistant Professor of Physiology, University College, London... .. 400 Dispersion Equivalents. Part I. By J. H. Gladstone, — FELRS. .... 401 On the Rate at which Electricity leaks through Liquids which are Bad ' Conductors of Electricity. By J. J. Thomson, M.A., F.R.S., Fellow of Trinity College, and Cavendish Professor of Experimental Physics in the University of Cambridge, and H. F. Newall, M.A., Assistant Demonstrator in Physics, Camubpridtey oso... hace: .. 410 The Development of the Branchial Arterial Arches in Birds, with ee Reference to the Origin of the Subclavians and Carotids. By John Yule pee 2 M.D., Senior Demonstrator of seDeONys Universo of Glasgow ... ss SR emerge ae eee A g . 429 On Radiation from Dull and a Surfaces. ae J. T. Bottomley, Note to a a. on the Blood-vessels of Mustelus Antarcticus (‘ Phil. Trans..’ 1886). By T. Jeffery Parker, B.Sc. Lond., Professor of Biology in the University of Otago (cs. hisciic. Diacseeccstss icon eee epee 437 On Rigor Mortis in Fish, and its Relation to Putrefaction. By J. C. Ewart, M.D., Regius Professor of Natural History, University of MUI ULED ....2....c0- sees ssneosvessssvosnsods oossncceacentonacaetecevsuensh Setoyas1( een 438 Electrochemical Effects on a ces Iron. ey Thomas Andrews, Note on the Functions of the Sinuses of Valsalva and Auricular Appendices, with some Remarks on the Mechanism of the Heart and Pulse. By M. Gollier, .2.0..:ccs-npcssateeseisivonnstechop siheeewedseudpntnersse sat 469 On Hamilton’s Numbers. By J. J. Sylvester, F.R.S., Savilian Professor of Geometry in the University of Oxford, and James Hammond, INE A: Caithness ruweonsh’ vadtcnbpbesnnnssdeestnuyicns suevd destenthspsbvdvassvait’ estes er 470 On the Indiction of the Explosive Wave and an Altered Gaseous Condi- tion in an Explosive Gaseous Mixture by a Vibratory Movement. By Lewis 0s) Wright... Nn i ti caiies- steeds cscetadincsvete ahve er 472 Note on a Communication entitled “ Preliminary Note on a Balanoglossus Larva from the Bahamas” (‘ Roy. Soc. Proc., vol. 42, p. 146). By W. ei. Weldon, MAA) 27) batisnleebeecentat issn sssckere hides dovntne eens 473 Note on the Anatomy of Asiatic Cholera as exemplified in Cases occurring in Italy in 1886. By CharlesS. Sherrington, M.B., M.A. 0... cesses 474 On certain Definite Integrals. No. 15. By W. H. I. Russell, F.R.S. .... 477 X1 A Geometrical Interpretation of the first two Periods of Chemical Elements following Hydrogen, showing the Relations of the fourteen Elements to each other and to Hydrogen by means of a Right Line and Cubic Curve with one real Asymptote. By Rev. Samuel Haughton, NS Fnac coon sau gnedsohdl naean ope! acucteansue siomeeesanvuasalels On the Force with which the two Layers of the healthy Pleura cohere. eemeseememre HMMS or VED, ABE Cc. avcta caeemccadhetdevat=rdanceseideasustedseansandversesis ices Total Eclipse of the Sun observed at the Caroline Islands on ee 6, 1883. By W. de W. Abney, Captain R.E., PRS... Note on Mr. Davison’s Paper on the Straining of the Earth’s Crust in Cooling. By G. H. Darwin, M.A., F.R.S., Plumian Professor of Astronomy and Experimental Philosophy in the University of ee MRO eae Ao 8 dae spy ens scoidasv amore bse ctesesdced a Svaaadacpheirdnasaaeeceeens A further minute Analysis, by Electric Stimulation, of the so-called Motor Region of the Cortex Cerebri in the Monkey (Macacus sinicus). By Charles E. Beevor, M.D., and Professor Victor Horsley, F.R.S., MEN ese co chee cicchinn sides wnbaatsitaes aoe On the present Position of the Question of the Sources of the Nitrogen of Vegetation, with some new Results, and preliminary Notice of new Lines of Investigation. By Sir J. B. Lawes, Bart., F.R.S., and J. H. Gilbert, M.A., LL.D., F.R.S., Sibthorpian Pr ofessor of Rural Economy in the University mercies ee ee a ee On Diameters of Plane Cubics. By John J. Walker, M.A., F.R.S. .0..... List of Presents PROCES Teme Resa EH Hee ESOS IESS SESTTH PROFS HEE H ROHR EATS HEIL SESS TEFS TR Tae ee ese=TBBSSTEDESEEHES 828 Note on some Experiments on the Viscosity of Ice. a J. F. Main, MA. DSc. SERS eee eee eee ee HH TEE e EE TEETH PETES ESET REET TESS TESS HEED PODS SOPGRT HES ESESSSED HFEF OES DEBS EEEE OOD No. 257. Page 482 482 . 482 483 483 The Air of Sewers. By Professor Thomas Carnelley, D.Sc., and J. S._ Haldane, M.A., M.B., University College, Dundee Pees cere sere rere ress seesesea ser eeer® POPS T PEE OOOO RETEST TES HEHE Hee SHEET EES ETE HSER HEHEHE TET HESS SESE HOTT ETH SHS ATET ASHP HDOR SHES SSES ELSE SSSS THALES SETE SEED Obituary Notices :— : Sues Freep TNR Pestag RG DE ehrey Exe LG cA ED 2 occ yan te. s-akecoe tases saeed casa atnesnnsauve dese ibs ncsecaeeseeustdan ene Sir Walter Elliot, K.C.S.I , LL.D Sir Joseph Whitworth Dr. Allen Thomson Prove eree ras MBs sees a ees SeFS PSMA REGS DOSF PHOT seeeasEHEEST OBOE TERS POPS SPS ee ares THHH TSH H SHS FE ES Se FDOT TAFE HTTP SHOTS SOOO ESD SHHeHTFO HEHE SES SFOITSIOS DORR Here eee eee este FH SETHE AE SEES -BEE THRE TESS SESS POSH HEFT HSEEHESH SETS SEES HESS SOOO HEED PROCEEDINGS OF Pe AL, SOG EET ¥. LO NLNLWPDA WAAAY January 6, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On the Occurrence of Silver in Volcanic Ash from the Eruption of Cotopaxi of July 22nd and 28rd, 1885.” By JW. MAnietT, M.D., F.B.S:; University of Virginia. Received November 26, 1886. A few months ago I received from Seftor Julian R. Santos, of Ecuador, formerly a pupil of mine in the laboratory of this Univer- sity, a specimen of volcanic ash collected at his place of residence, Bahia de Caraguez, on the coast of the Pacific, about 120 miles nearly due west from Cotopaxi. This, the highest and among the most mighty of the active volcanoes of our globe, burst forth into eruption about 115 p.m. on the 22nd of July, 1885, and the ash began to fall at Bahia de Caraguez at 7 a.M. on the next day, the 23rd. It fell there to the depth of several inches, this fact alone indicating the discharge of an enormous amount of solid matter into the atmosphere, although Sefor Santos wrote to me that the unsettled condition of the country, disturbed by revolutionary movements, prevented his making extended enquiries which might have ascertained the area covered by the fall of ashes. The specimen sent me consisted of a very finely divided powder, mobile and soft to the touch, of light brownish-grey colour. Under the microscope it appeared to be made up of minute granules and spicules, in general with sharp, more or less splintery edges. These were for the most part colourless and transparent, or white and trans- lucent; some were reddish, some dark bottle-green, some brown, some black and opaque. Most of those clear enough to freely trans- mit light showed brilliant colours in a field of polarised light. Quartz, two felspars (one white, and one pink or reddish), augite, magnetite VOL. XLII. B 2 On the Occurrence of Silver in Volcanic Ash. [Jan. 6, (strongly attracted, and easily removed by the end of a magnetic needle), and thin scales of deep red specular iron oxide were easily distinguished. The ash on being strongly heated before the blowpipe, or even in considerable quantity in a small platinum crucible over the blast lamp, turned dark red-brown, and fused to a nearly black slag. On being boiled in its original state with water it gave up 0°21 per eent. of soluble matter. The solution gave very distinctly the reactions of chlorine, a sulphate, and sodium; in a less marked degree the reactions of potassium. On boiling with strong hydrochloric acid, 6°94 per cent. was dissolved, in addition to that already extracted by water; the acid solution was deeply coloured by iron. The specific gravity of the ash was found = 2°624 at 18° C. as compared with water at the same temperature. An analysis of the material taken as a whole, 7.e., without any previous mechanical separation of its consistent minerals, and without previous digestion with water or acid, but dried at 100° C., gave the following results :— Osis ce ai bla rk ae Sens le wins 56°89 DO on aio ns SOS MBE Mate oi ev olelpys trace AN Olga ote ca'e ei crepetal Vereretanana otek 19°72 Wes Oa aie cd . kee uaey iain ae 5 yi HOO esc Sis chr RLS ee 3°6 IVE as nate ES a is den ort be trace MeOL i. 600 2G Benes 1:91 CaO s heel. Bia ie eae icaere 5°87 Be Lah Sk a Rae : “a RO). Hise Hr ae cet aan Tass, So 0te Ria AND. cesta alee trace TNC ON, Ha Wa RSE B IR Pr f CT | cL SLO aks RE a i oO Ca AISI LS ce na POLIT ole NARA SRN DR, oh dete 4 ED OAT ity FR saat lls ene 0°62 99°82 Silver was first noticed after fusing as usual with mixed sodium and potassium carbonates, and dissolving in excess of hydrochloric acid, on the addition of sulphuretted hydrogen to the solution, which had been freed from silica; the sulphur thrown down by ferric chloride present was observed to be distinctly brown, and on being filtered out. and carefully burned off before the blowpipe it left a minute bead of metallic silver. All the reagents and vessels used were scrupulously examined, but the silver could not be traced to any of them. It was 1887.] On the Continuity of the Liquid and Gaseous States. 3 afterwards found that the metal could be obtained from the ash by furnace assay—fusion with pure lead carbonate, sodium carbonate, and a little cream of tartar, and cupellation of the lead button produced ; and a comparative experiment was made, with negative result, using larger quantities of the same reagents, but omitting the volcanic ash. It was ascertained that silver could be extracted from the ash by boiling it with a solution of ammonia, or of potassium cyanide, or of sodiam thiosulphate, but the metal was not dissolved out in appreci- able amount on boiling with nitric acid. Hence, as seems most probable, it was present in the ash as silver chloride. The fact of its being found in the solution in hydrochloric acid of the mass resulting from fusion with the alkaline carbonates, is of course easily explained by the solvent action upon silver chloride of the chlorides of sodium and potassium, and (when such minute quantities are concerned) of hydrochloric acid itself. The discovery of silver in the ash in question adds for the first time this metal to the list of elementary substances observed in the materials ejected from volcanoes, and the addition derives some special interest from the fact of the ash having come from the greatest of the volcanic vents of the great argentiferous chain of the Andes. Lead, which was found by Senor Santos himself, when a student here in 1879, in a specimen of ash from the eruption of Cotopaxi of August 23rd, 1878,* was sought for in the ash now reported upon, but neither it nor any other heavy metal beside silver was detectable. Several concordant experiments proved that the silver was present to the extent of about 1 part in 83,600 of the ash, or about two-fifths of a Troy ounce per ton of 2240 pounds. Small as is this proportion, it must represent a very large quantity of silver ejected during the eruption, in view of the vast masses of volcanic ash which must have been spread over such an area as is Re by the fall at so distant a point as Bahia de Caraguez. II, “ Preliminary Note on the Continuity of the Liquid and Gaseous States of Matter.” By WiuLiIAm Ramsay, Ph.D., and SYDNEY YounG, D.Sc. Communicated by Prof. G. G. STOKES, D.C.L., P.R.S. Received November 30, 1886. For several years past we have been engaged in an examination of the behaviour of liquids and gases through wide ranges of tempera- ture and pressure. The results of our experiments with ethyl alcohol have recently been published in the ‘ Philosophical Transac- tions ;’ those with acetic acid in the ‘ Journal (Transactions) of the Chemical Society’; and the Royal Society have in their hands a * ‘Chem. News,’ Oct. 17, 1879 (vol. 40, p. 186). B 2 4 Drs. W. Ramsay and 8. Young. [Jan. 6, similar investigation on ether. We have also finished a study of the thermal properties of methyl alcohol. In consequence of a recent publication by Wroblewski, of which we have seen only the abstract (‘ Deutsch. Chem. Ges. Berichte,’ 1886 (Referate), p. 728), we deem it advisable to communicate a short notice of an investigation in which we are at present engaged. We find that with the above-mentioned substances, acetic acid excepted, whether they are in the liquid or gaseous state, provided volume be kept constant,a simple relation holds between pressure and temperature. It is p = bT—a. This is evidently a simple modification of Boyle’s and Gay-Lussac’s laws; for at low pressures, where volume is large, the term a approaches and finally equals zero, while 6 diminishes and finally becomes equal to the value of c, calculated from the ordinary equation,. acl = We have as yet only had time to apply this formula with ethyl ether to the liquid state; and as we are not yet quite certain whether the relation holds when 1 gram of ether occupies volumes between 4 and 20 c.c., we are at present engaged in measurements of volumes and pressures at temperatures between 220° and 280°. Assuming the above relation to be true (and it is at all events a close approximation to truth), it is possible to calculate those portions of isothermals included within the liquid-gas area, and represented in Andrews’ diagram by horizontal straight lines. We have calculated a few of these isothermals for ether, and find that the areas above and below the horizontal lines (see woodcut) are equal, when measured by a planimeter. Reserving a full discussion of the subject until the completion of our experiments, we would here point out the similarity between the equation p = bT—a, and those proposed by Clausius and by van der Waals to represent these relations. Clausius’s formula is _ RE @ - Ue T(v +p)” and van der Waals’ p= eT Pe: v—hb ¥v? In these formule Clausius’s « and c are equivalent to van der Waals’ b and a respectively, but R has a different signification. We find that a somewhat similar formula agrees better with expe- riment than either of the above; it is On the Continuity of the Liquid and Gaseous States. 40000 HCV S where R, b, and a have the same meaning as in van der Waals’ formula. This formula expresses the results of experiments with great accuracy, where the volume of 1 gram of ether occupies not less than 25 ¢c.c.; but at smaller volumes it ceases to represent the facts. It is to be noticed that both Clausius’s equation and ours introduce 6 | Prof. W. C. Williamson. [Jan. 6, T into the denominator of the second term; they evidently differ from our first equation p = JT—a, in which a is independent of temperature. We shall soon be in a position to communicate the results of this investigation, giving full data. [January 18th, 1887.—We have alluded to Clausius’s formula, ae aS a his latest published formula is eateeee RT __© __. where 0=aT"—b. As the second term is here P ya O(v+fB)? also a function of temperature, it is evident that his last equation is also not in accordance with the simple relation p = bT—a]. III. “Note on Lepidodendron Harcourti and L. fuliginosum (Will.).” By W. C. Wiuutamson, LL.D., F.R.S., Professor of Botany in the Owens College and in the Victoria University. Received November 27, 1886. In March, 1832, the late Mr. Witham read to the Natural History Society of Newcastle-upon-Tyne the first public notice of the classic specimen of Lepidodendron known as Lepidodendron Harcourtw. Still later (1833) he published further figures and descriptions of the same specimen in his work on ‘ The Internal Structure of Fossil Vege- tables.’ Additional figures and descriptions of the same object appeared in the second volume of Lindley and Hutton’s ‘ Fossil Flora,’ and in Brongniart’s ‘ Végétaux Fossiles.’ But notwith- standing all these publications the exact plant to which they referred has long been doubtful. I hoped to have found either the original specimen] in the museum of the Yorkshire Philosophical Society or the sections described by Lindley and Hutton in that of the New- castle Society; but, though carefully sought for, I long failed to discover either one or the other. In 1871, I laid before the Royal Society my memoir, Part II, “On the Organisation of the Fossil Plants of the Coal-measures,” in which I figured (Plate 25, fig. 12), a plant that seemed to me to be identical with ZL. Harcourtii; and in Part XI (1880) of the same series of memoirs, I gave further representations of the same plant (Plate 51, fig. 10; Plate 49, fig. 11). Since the publication of the latter memoir I have obtained a fine series of specimens, which appeared to me to approach still more closely to the various representations of Lepidodendron Harcourtti, referred to above, and which inclined me to think that I had hitherto included two species under a common name. The two forms unmistakably belong to a common type, to which I 1887.] Lepidodendron Harcourtit and L. fuliginosum. 7 have frequently had occasion to refer as ‘‘ the type of L. Harcourtit,” characterised by the possession of a very distinct parenchymatous medulla, surrounded by a sharply-defined non-exogenous vascular zone—the Hiwi médullaire of Brongniart—and by the almost entire absence of any exogenous vascular zone; the chief exception to the last feature being represented in the Plate 49, fig. 11, referred to above. . One of the most characteristic features seen in my new specimens occurs in the structure of the foliar bundles. These have been large, and in transverse sections of a stem they are rendered increas- inely conspicuous, by the disappearance of a considerable amount of cellular tissue which originally belonged to them, but which is now only represented by a clear vacant space. What remains of these bundles is equally characteristic. In each case the bundle appears to be a double one; owing to the preservation not only of its vascular or zylem part, but also of a distinct and separate string of what has obviously been a modification of the hard bast of the phloem part of the bundle. on me bo or ON OVEN OV or on th tb to bw nO OU OU ON Ee OO oo tS COD COND nse SASS Ghee rh S be me bo Se me pw Hee ho H bo bo bo mI oo co 0 OO Or bo JT bo > Nn — bo bo OV bo ~I J S — imal (Je) oS a S IQ OPBH oo ©Om NwH 42 cee ee eevee eee@ees eoese eeecee eeercee eeese eeoee ceeee ees oe eee ee eeeeese Ist Mr. J. N. Lockyer. 2nd 3rd 4th hundred.| hundred.|hundred. 6 uf 1 1 1 l 1 1 1 il 21 52 37 1 1 6 1 6 6 1 1 1 17 26 29 21 48 ibs 9 rf 3 1 6 1 2 1 5 4, iL 3 1 1 1 1 1 1 3 1 On the 5th 2 pt Or 24 21 el [Jan. 20, 6th «th hundred.|hundred. | hundred.| hundred. 4, 3 ia. 45 i 65 18 bo 14, 2 ae 1887.] Sun-Spot Observations made at South Kensington. 43 1st 2nd 38rd 4th 5th 6th 7th hundred.| hundred.} hundred.| hundred.| hundred. |hundred. |hundred. a SCO SO OO ho On Ww bo me oo | 1 60 SLM re x oo bo ou Co i OU — bt oD ht OD bw bo om (op) iw) L2Yo OH de bho o> bo oa) (Jy) oa Co co bo Ww a IS ae a aR a ee ee a es eee ee) ae 44 Mr. J. N. Lockyer. On the FO Me is 15 55 3 SDS as) ai 18 6 1st 2nd 3rd Ath 5th in ee 13 Vo eat 25 26 a OWWOeH De eeoee bo wo SHE poe ~J seo ee eeoaee on - CO FOS *eeee —_ We Wee he. a —- Ld Se 6th 83" Oo mw FPO ss [Jan. 20, 7th 73 re bo 1887.] Sun-Spot Observations made at South Kensington. 45 Ist 2nd 3rd 4th 5th 6th 7th hundred.) hundred.|hnndred./hundred.|hundred.|hundred. |hundred. Or 2) for) co oe bt 10 5 50 On oo a or) fo) ~T bo 14 8 10 pol pel POorwWW 46 Sun-Spot Observations made at South Kensington. [Jan. 20, ~ Most Widened Lines. b-D Region. YEARS — 1879-80 1880-! . 1881-2 1882-3 1883-4 1884-5 1885 SiHundred eetHundred 3™4Hundied 4¢hHundred 5'hHundred 6°OHundred 7th Hundred ™ “Y *, = T = ie _— if = ie CIEE. — ee 7 1 Un krtows | Su hslUreces set a 2 Cs OE pe St ne ee | Se led ed ike kabel 1 k = H = = - eee eS as - Se ane ee 1887. ] Presents. 47 Presents, January 20, 1887. Transactions. Dresden :—Kaiserliche Leopoldino-Carolinische Deutsche Akad. der Naturforscher. Leopoldina. Jahrg. 1884-85. Heft XX-— XXI. 4to. Halle 1884-85; Nova Acta. Bande XLVII- XLVIII. 4to. Halle 1885-86. The Academy. Verein fiir Erdkunde. Verzeichnis von Forschern in wis- senschaftlichker Landes- und Volkskunde Mittel-Huropas. 8vo. Dresden 1886. The Association. Giessen :—Universitat. Thesen, &c. Forty-eight in all. 8vo. and 4to. Giessen, &c. 1884-86.. The University. Heidelberg :—Universitat. 10 Inaugural-Dissertationen with seven other pamphlets. 8vo. and 4to. Heidelberg, &c. 1884-85. The University. London :—Odontological Society. Transactions. Vol. XIX. No. 2. 8vo. London 1886. The Society. Photographic Society. Journal and Transactions. Vol. XI. No. 3. 8vo. London 1886. The Society. Montreal :—Royal Society of Canada. Proceedings and Trans- actions. 1885. 4to. Montreal 1886. The Society. Miinster :—Konigliche Akademie. Inaugural-Dissertationen, &c., 26 in all. 8vo. and 4to. 1885-86; Indices Lectionum. 4to. 1886-87. The Academy. Naples:—Accademia delle Scienze Fisiche e Matematiche. Rendi- conto. Anno XXV. Fasc. 1, 3. 4to. Napoli 1886. The Academy. Netherlands :—Nederlandsche Botanische Vereeniging. Verslagen en Mededeelingen. Deel 4. Stuk 4. 8vo. Nijmegen 1886. The Association. Palermo :—Reale Accademia. Bollettino. Anno III. Num. 1-3. Ato. Palermo 1886. The Academy. Paris :—Ecole Normale Supérieure. Annales. Année 1886. Sup- plément, & No. 11. 4t0. Paris 1886. The School. Philadelphia :—American Philosophical Society. Proceedings. Vol. XXIII. No. 123. 8vo. Philadelphia 1886. The Society. St. Petersburg :—Comité Géologique. Bulletin 1886. No. 7-8. 8vo. St. Pétersbourg 1886; Mémoires. Vol. III. No. 2. 4to. St. Pétersbourg 1886; Bibliotheque Géologique de la Russie. Rédigée par 8. Nikitin. 8vo. St. Pétersbourg 1886. The Committee. Vienna:—Anthropologische Gesellschaft. Mittheilungen. Band XVI, Heft lund 2. 4to. Wren 1886. The Society. 48 Presents. [Jan. 20, Transactions (continued). Yokohama :—Asiatic Society of Japan. Transactions. Vol. XIV. Part 2. 8vo. Yokohama 1886. | The Society. Observations and Reports. Bergen :—Bergens Museums Aarsberetning. 1885. 8vo. Bergen 1886. The Museum. Bombay :—Colaba Observatory. Report for the year ended 30th June, 1886. Folio. Bombay 1886. The Observatory. Calcutta :—Meteorological Observations recorded at six stations in | India, 1886. July and August. Folio. Meteorological Office, India. Chile :—Reconocimiento dei Rio Buta-Palena i del Canal Fallos. 8vo. Santiago de Chile 1886. Oficina Hidroerafica. Christchurch, N.Z.:—Hast and West Coast and Nelson Railway. History of the Efforts for its Construction. 8vo. Christchurch 1886. Mr. John T. Matson. Melbourne :—Australasian Statistics. 1885. Folio. Melbourne 1886. The Government Statist. Illustrated Handbook of Victoria, prepared in connection with the Colonial and Indian Exhibition, London, 1886. 8vo. Melbourne 1886. The Royal Commission for Victoria. Paris :—Bureau des Longitudes. Annuaire 1887. 12mo. Paris Wee ys The Burean. Pulkowa :—Observatoire. Positions Moyennes de 3542 Etoiles déterminées a l’aide du cercle méridien de Poulkova dans 1840-1869, et réduites a Pépoque 1855. Folio. St. Péters- bowrg 1886. The Director. Washington :—Department of Agriculture. Report, 1885. 8vo. Washington 1885. The Department. Daubrée (A.) Les Météorites et la Constitution du Globe Terrestre. 8vo. Paris 1886. The Author. Delauney. Explication des Taches du Soleil. 8vo. Paris 1886. The Author. Henderson (James) A Treatise on Metallurgy. 4to. New York 1857. The Author. Jones (Prof. T. R.) and J. W. Kirkby. Notes on the Distribution of the Fossil Ostracoda of the Carboniferous Formation of the British Isles. 8vo. [London] 1886. The Authors. Melnikow (M.) Geologische Erforschung des Verbreitungsgebietes der Phosphorite am Dnjester. 8vo. 1885. The Author. 1887. | On a Perspective Microscope. 49 Shelford (W.) and A. H. Shield. On some points for the considera- tion of English Engineers with reference to the Design of Girder Bridges. 8vo. London 1886. The Authors. Trois (Hnrico F.) Annotazione sopra un esemplare di Trygon Violacea. Svo. Venezia [1886]; Considerazioni sul Dentex Gibbosus. Svo. Venezia 1886. Prof. T. R. Jones, F.R.S. January 27, 1887. Professor G. G. STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On a Perspective Microscope.” By Grorce J. Burcu. Communicated by J. RusSsELL ReyNoups, M.D., F.R.S. Received January 7, 1887. (Abstract.) In 1874 the author discovered a form of microscope giving constant magnification along the optic axis, so that objects were shown by it in microscopic perspective. By writing (f;+f,+H) for the distance between two thin lenses, he obtained for the formula of the system folht+H)u—fAh(AthtH) _ Hu—f,(fi+ H) u being the distance from the object to the first lens, and v that from the second lens to the image. Putting H = 0 in this equation, three things result. 1. dv/du, which represents the longitudinal magnification, becomes constant, namely —(f,/f,)?; 2. The lateral or angular magnification, f,/f,, is also constant ; 3. A picture of an object so magnified, drawn with the camera lucida, when viewed from a distance f,/f, times less than that at which it was drawn has the perspective belonging to an object magnified (f,/f,)? times. The distance at which the eye must be placed is great, but may be reduced by employing three lenses, the distance between the first and VOL. XLII. E V5 50 Prof. G. F. Fitzgerald. On the [Jan. 27, second being (f,+fo+fo/m), and that between the second and third (fo ths + mfo)- If the lenses are nearly but not quite in the afocal position, greater power and a wider field may be obtained, but it is at the expense of the penetration, which may, however, with advantage be limited to the thickness of the object. The instrument cffers great advantages for artistic purposes, but lenses or mirrors of specially wide angle are needed for the farther development of the invention. The optical conditions of a system of two thin lenses at varying distance apart are shown by diagrams. In Diagram I the w and v of the formula employed are set off as abscissee and ordinates, and the curves (which are rectangular hyper- bolas) drawn for several values of H. In the afocal position of the lenses the curve degrades into a line which is a tangent to all the hyperbolas at the point (f;,/.). The locus of vertices and locus of centres of these curves being straight lines, and the hyperbolas ali touching the point (fj,/2), it is shown that the principal foci, principal points, and equivalent focal length for any given position of the lenses can be found by rule and compasses, without drawing the curve. In Diagram II the actual position of the lenses, their principal foci, separate and combined, and the principal points, positive and negative (answering to the vertices of the curves in Diagram I), are plotted down as abscisse, the values of H on an enlarged scale being taken as ordinates. Diagram III shows the same for two lenses of equal focal length. Comparison of these two diagrams suggests the employment of the term ‘‘ Pseudo-Principal Points” for those positions at which the magnitude of the image is in the constant ratio /,/f, to that of the object for every value of H, inasmuch as the distance from these to the principal points gives the measure of the “ penetration ”’ of the system. If. “ On the Thermodynamic Properties of Substances whose Intrinsic Equation is a Linear Function of the Pressure and Temperature.” By Professor GEORGE F. FITZGERALD, M.A., F.R.S. Received January 11, 1887. Professor Ramsay has communicated to me that he and Mr. Young have found that within wide limits several substances in the liquid and gaseous states have the following relation connecting their pres- sure (p), temperature (T), and specific volume (v), pA Ole a, where a and 0b are functions of v only. 1887.) Thermodynamic Properties of Substances. D1 Now in this case the following are the forms that the thermo- dynamic equations assume. ‘T is temperature, and @ is entropy, and ec and e are functions to be investigated, c being = dI/dT, where 1 is * the internal es and e = dI/dv. Then Tdé=cdT + (e + p)dv. From this, as de/dT = dc/dv, we have dp/dT = e+ p/T. But dp/dT =a by the intrinsic equation, and is a function of v only, .-.e=-—b, which is a function of v only, .-. defdl =O, . deldv = 0, .*. is ca function of T only, and dI = cdT +e dv gives— l=fcdT+fedv=y+2, where y is a function of temperature only, and \ a function of volume only. : Similarly, Td¢é=cdt+aT dv; oy OD == qi dttads, as | ted, o= P+a, where © is a function of temperature and « of volume only. Hence we see that c, the specific heat at a constant volume, is a function of the temperature only, and the internal energy and the entropy can be expressed as the sums of two functions, one a function of the temperature only, and the other of the volume only. For the specific heat at constant pressure we have— _ C= c+(o+p) 2 = Dia i dilien ea where a’ = da/dv and b'= db/du, Ta? aA Tu a ne apt In the case of the particular values of a and b that Professor Ramsay has suggested to me, when the intrinsic equation assumes the form— E 2 52 Prof. W. K. Parker. [Jan. 27, and when consequently m a= v—v,’ b = See? we have e= pu”, and es (n—1)p =y- - gut p=T+Rlog (v—%), — TR + n(o— Yy)20-2 1 It would be most important if by some method, Kcenig’s for in- stance, or by inserting a small microphone into a tube, the velocity of sound in substances in various states could be accurately determine, as that would enable us to determine C and ¢ Sepatatetie Ill. “On the Morphology of Birds.” By Professor W. K. PARKER, F.R.S. Received January 138, 1887. (Abstract.) Introductory Remarks. During the time that the special study of the development of the skull has occupied my attention, the rest of the skeleton has been neglected; it has, however, had its cultivators in no small number. In a limited degree the skeleton has been worked out by me;—for instance, the shoulder-girdle and sternum in the Vertebrata generally ; in birds, the whole skeleton did at one time—a quarter of a century ago-——take up much of my thought. The development of the skeleton, generally in this Class, is a subject of great interest, and I am anxious to catch up all the scattered results that lie before me, of the excellent but extremely limited labours of other biologists. I did begin the study of the development of the limbs, sternum, pelvis, and spine, in 1842, and some of the results will be brought forward in the present paper. This will be, I trust, but the. first-fruits of my most recent work ; for, during the long years that have elapsed since this research was fairly begun, I have lost no opportunity of laying up in store embryos and young of birds of many kinds. These stores, if well worked out, will yield a series of papers like the one now offered to the Society.* * Although I have for many years past kept a register of the presents of 1887. | On the Morphology of Birds. 53 The bibliography of my published papers on the Osteology of the Thorax partly, and of the Skull largely, is given in the general Bibliographical List. It has been necessary to do this, as every scrap and part of the older work is wanted, now that an attempt is made to build the old and the new into something like a structure having form and fulness. There are several things that go to increase the interest in the morphology of these culminating Sauropsida at the present time. First.—The discovery by Gegenbaur, Huxley, and others, of the close relationship of birds and reptiles, especially of the extraordinary fact that the hind limb and pelvis of even the most minute bird pass through a stage in which they correspond almost exactly with the hind limb and pelvis of the most gigantic kinds of extinct reptiles — the Dinosaurs or Ornithoscelida. Secondly.—The recent discoveries of biologists as to the composition of the Cheiropterygium in the various types of air-breathing Verte- brata. It is now well known that the five-fingered hand and the foot with five toes are the specialised modern representatives of hands and — feet that had at least seven rays in their composition. And, thirdly—the study of the development and general morphology of birds is, at the present time, of great interest,—now that we are looking to the study of metamorphosis for some initial elucidation of the mystery as to the origin of the various types of Vertebrata. The labour of each succeeding day at this culminating Class makes it more and more impossible for me to conceive of birds as arising direct from the Dinosaurians, or indeed from any other order or group of reptiles. Long attention to the metamorphosis of the Amphibia has intensified this difficulty to me; for the newly-transformed frog or newt appears to me to be the true counterpart of a newly-hatched reptile—snake, lizard, turtle, or crocodile. Hach of these young creatures, whether it has undergone a true metamorphosis, or has been the subject of pre-natal transformation, is evidently an wmago; although an imago that continues to grow. Now each amphibian has its own larva, for the larve of the various species have their specific differences. The thousand known species of existing Amphibia—Anurans, Urodeles, and Coecilians—and all the fishes that undergo metamor- phosis, are as truly, if not as remarkably, distinct from each other in their larval as in their imago form;—as much so as is the case in insects, or any other of those invertebrate types that are truly meta- morphic. materials for thisand other parts of my work, I cannot reproduce it here ; but must use this opportunity of thanking a host of kind friends for gifts which, in abundance and variety, are somewhat embarrassing. 5A Prof. W. K. Parker. (Jan, 24) If many of the existing Vertebrata are metamorphic now, is it not very probable that they were all metamorphic once ? The fact that we have, even now, such forms as the larval lamprey (or Ammocecete), the larvee of Ganoids and Dipnoi, and the tadpoles of newts and frogs, suggests to me the possibility of the existence of huge swarms of low Proto-Vertebrata in the early ages of the inhabited planet. If such proto-vertebrate forms existed, then it is quite supposable that a metamorphosis may, from time to time, have taken place, of this and that quasi-larval forra into archaic reptile, ancestral bird, or primitive mammal. IT am not afraid that anyone familiar with the development, structure, and habits of the existing Amphibia will see any difficulty in the passage of a metamorphic into a so-called non-metamorphic type, during time, and under the pressure of new outward conditions, —when the dilemma offered to the supposed low vertebrate was Transform or perish. To me it seems that the creature’s necessity was Nature’s oppor- tunity; and that, during long ages, the morphological force had accumulated in those low forms an enormous surplusage of unused energy which, in the ripeness of time, blossomed out into this and that new and noble type. Of all the types of Vertebrata, there is none like the bird of high degree for illustrating what Professor Huxley calls “the threefold law of evolution,”’* namely, overgrowth of some parts, starvation and even death of others, and fusion of parts originally distinct. No kind of vertebrate whatever presents to the osteologist so hope- less an enigma in the adult skeleton as that of the bird; in the overgrowth of certain parts, the abortion or suppresion of others, and the extensive fusion of large tracts of skeletal elements. Hence this Class has largely acted upon the morphological mind ; the “ Comparative Anatomist”’ has, of necessity, undergone evolution into the ‘‘ Morphologist,” and the latter has had to be refined and developed into the ‘* Hmbryologist.” _. In the bird class we meet with this remarkable phenomenon, namely, that the swiftest creatures by far that inhabit the earth have had, for the purposes of their most consummate mechanism, the greatest loss of freedom of the individual parts of the skeletal frame- work. Between the pigeon, on one hand, above, and the emeu, on the other, below, there are several families of related birds; but there is no direct superposition,—they are obliquely above or below each other. * See his paper “On the Application of the Laws of Evolution to the Arrange- ment of the Vertebrata, and more especially of the Mammalia” (‘ Zool. Soc. Proc.,’ December 14, 1884, pp. 649-662). 1887.] On the Morphology of Birds. Dd Amongst the Carinate, which lie in the intermediate space, there is none better for the purposes of study than the common fowl; to this type I have devoted most attention, and have now worked cat the limbs in as many stages as I formerly did the skull. I can now give an account of the vertebral column with the ribs and sternum, the limb-girdles and limbs, from the end of the seventh day of incubation; by which time the hyaline cartilage is perfect, and certain even of the bony tracts are begun. The fowl is an intermediate form between the emeu and the pigeon; but most akin to the latter. I shall now confine myself to what is seen in the development of the skeleton (excluding the skull) in this medium type. The vertebral column, at the end of a week’s incubation, is formed of hyaline cartilage; up to the end of the true sacrals, the notochord is completely invested with cartilage; but, behind those four segments, only at the sides. The notochord has its constrictions in the middle of each centrum, and is most dilated at the intercentra. The neural arches do not nearly meet above; the atlas is in four pieces—a superficial and an inner piece to the centrum, and a pair of arch-rudiments; the inner segment of the centrum becomes the odontoid process of the azis. Between the axis and the first true sacral, all the vertebre have separate ribs; in the cervical region, except near the dorsal region, there are small styloid cartilages lying horizontally, which have their head, or thick end, wedged in between the upper and lower transverse processes. Near the dorsals they are transversely placed, and then begin to develop a descending process. The first vertebra of this stage with complete ribs becomes, by absorption of the lower part of the arch, the last cervical in the adult. Behind the twenty pre-sacrals there are fifteen sacrals, and this series has its subdivisions. The first develops ribs (it is dorso-sacral), the next three develop minute but distinct ribs, ike those near the lower part of the neck; these are lumbo-sacral. Then come the four sacrals with no ribs, and then the seven uro-sacrals, the first two of which have rib-bars that ossify separately, below the upper transverse processes, which latter form a complete series from the third cervical to the last free caudal sezment. Of those there are five; then come five more paired imperfect rudi- ments, clinging to the terminal part of the notochord. At the end of the 8th day there are six of these, with the last elon- gated, and the notochord projecting behind far enough for three or four more rudiments. At the end of the 10th day the vertebral chain has undergone a great 56 Prof. W. K. Parker. [Jan. 27, change. The atlas is still composed of four distinct pieces of car- tilages, but the ribs have become fused above and below with the transverse processes, and the notochord is now most constricted at the entercentra. Besides this, in the pre-sacrals, it is constricted in two places within each centrum; so that each centrum in the modern bird corresponds to three subdivisions of this axial chord. For two or three days there is evidence of an archaic subdivision of the notochord into three times as many vertebral divisions as are made now in the modern bird. In the sacral the constrictions are fewer ; they are only at the inter- centra, and in the middle of the centrum. The only absolutely necessary part of the sternum is that where the sternal ribs are attached; that is a very small part, and the rest is for the attachment of the huge muscles that act upon the wings, and for the obliqui and recti abdominis. The limb-girdles are each in three pairs of distinct cartilages. In front, the scapula, the minute pre-coracoid, the coracoid; behind the ilium, pubis and ischium; the pre-pubis is part of the ilium, and that has two regions, the pre-ilium and the post-ilium. These parts in the bird are not continuous tracts of cartilages, ossified by several centres, but are distinct, first as cartilages, then as bony tracts; those of the shoulder keep distinct; those of the hip soon coalesce. The wings at the end of the 7th day are three-toed webbed paws, with all the digits turned inwards. The rods that compose the main part of it are composed of solid cartilage ; the humerus, radius, ulna, and lst and 2nd metacarpals have a bony sheath round their middle part ; the ends of the digits and the carpals are but partly chondrified. Fwe carpal nuclei, however, can be made out, and the two proximal nuclei are known to be further subdivided, each into two, in other types; hence we can already account for seven carpals in the bird, which has only two in the adult, in a free state. Moreover, the lst digit has two, and the 2nd three phalanges, the normal number, as in lizards; the 3rd, which should have four, but in birds has as a rule only one, has now two, as in the ostrich, and a few other birds; there is no sign at the end of the 7th or even of the 8th day of incubation of any more than three digits, but we have in the wrist an intermedio-radiale, a centralo-ulnare, and three distal carpals, answering to the three developed metacarpals. The digits up to the end of the 8th day are rounded and flattish, and are quite like those of a young newt or frog. But in two days more, at the end of the 10th day, the wing has almost acquired the adult form ; and one more bony centre, that of the lst metacarpal, has appeared. The overgrowth of the 2nd distal carpal and the 2nd metacarpal, 1887. ] On the Morphology of Birds. D7 with its large and dilated digit, has arrested the distal carpal of the Ist or short digit, the “ pollex.” This is the last nucleus to chondrify. Tt is still a very small, limpet-like disk of cartilage, and is now only to be seen on the flexor face of the manus, inside the top of the 2nd metacarpal ; the distal carpal of the 3rd ray is also small as compared with the large crescentic 2nd distal nucleus. It is thrown on to the ulnar or outer side of the manus, by the overgrowth of the middle rod and its carpal. The curve of the digits at their end is now, not inwards, or to the radial side, but outwards; and the two developed distal segments form now the core of two claws, that of the first, or pollex, being of considerable length. Thus, by the end of the 10th day, the reptilian type of fore-foot has been attained, and the amphibian type lost; whilst the limb as a whole is now a fore-leg no longer, but a wing, thoroughly specialised by evolutional transformation. The fore-limb has not simply become modified into a wing by the shortening of the pollex and 3rd ray, the enlargement of the 2nd, and the abortion of the 4th and 5th of a fore-paw, like that of the lizard; but we have now the Justorical representatives of three more rays which have cropped up since the end of the 8th day. I have repeatedly noticed that aborted parts, like overshadowed plants, are late to appear, and soon wither, or are arrested in their growth. This is the case here, for the new rays are late, small, and scarcely functional in the fullest development. They are not lost, however, but, like certain larval structures to be found in the skulls of the highest types of birds, they are built up into the finished wing, although they form an unimportant part of it as far as function goes. The first of these additional rays is the “ pre-pollex;” this is a lunate tract of fibro-cartilage attached to the inner face of the Ist metacarpal. The other two are composed of true hyaline cartilage, and appear, one on the ulnar side of the 2nd, and the other on the ulnar side of the 3rd developed metacarpal. I have described them as intercalary metacarpals, for they seem to be the starved twins of the 2nd and 3rd large rays: each distal carpal, very probably, in the archaic forms carried two rays. Thus there is supposed, for such a fore-limb, a digit inside the pollex of the modern bird, and then two pairs of rays, of which only the inner in each case has been retained. The paddle of Ichthyosaurus shows this kind of primitive cheiroptery- gium, admirably. Thus we can account for seven carpals and six digits in the wing of the modern bird; in the legs the specialisation is not so intense, but is very great; the study of the embryonic stages shows in it many parts that the adult bird gives no signs of whatever. Instead of there being even two tarsals, free and functional, there is 58 On the Morphology of Birds. [Jan. 27, only one, and that has merely the function of a ‘‘sesamoid,” and has been mistaken continually for a bone of that sort; that nucleus answers to our naviculare, morphologically termed the “centrale.” Notwithstanding the extreme diversity in the habits of existing birds, and the yreat difference seen in their shank bone, this part is always single, although composed of three metatarsals. As in reptiles, the joint at this part is not between the astragalus and tibia, as in mammals, but through the tarsal series; no sign of this structure is seen in the adult bird. That which appears to be the condyloid end of the tibia is a row of tarsal bones, the tibiale, fibulare, and inter- medium; these have long been known as separate bones in young birds, ae their distinctness in the early embr yo as cartilaginous nuclei has only lately been made out. I have been able, however, to demonstrate this repeal ok in different kinds of birds. The centrale also, although seen in the embryo as one of the tarsal series, was not properly identified ; it is a constant element, but becomes degraded. The distal series of tarsals exists asa single tract of cartilage, and then as a single plate of bone. But it is related to three metatarsals, and the middle or thick part is the first to chondrify in the embryo, and to ossify in the chicken or young bird; there are here three connate nuclei, with very slight signs of distinctness. The whole mass answers to our middle and external “ cuneiform bones,” and to the inner half of the “os magnum.” Thus five tarsals can be always made out clearly, and two more accounted for. The lst metatarsal, which has been known, for some time, through the valuable researches of Morse, to have occasionally a proximal as well as a distal rudiment, has, I find, always a proximal rudiment as well. Then, as Dr. G. Baur and Miss A. Johnson have shown, there is a 5th metatarsal; it is a small pisiform cartilage, which soon coalesces with the 4th, and with the great distal tarsal. I can only find a “‘nre-hallux” by turning to Teratology, and this is not the lawfal method. There may, however, be some “reversion” or “atavism”’ in the polydactyle foot of the Dorking fowl, which has a well developed ‘ pre-hallux ” and a double “hallux;” the twin digits of that part have a very ichthyosaurian appearance. 1887.] | Presents. o9 Presents, January 27, 1887. Transactions. Baltimore :—Johns Hopkins University. Circulars. Vol. VI. No. 54. 4to. Baltimore 1886. The University. Cambridge :—Philosophical Society. Proceedings. Vol. V. Part6. 8vo. Cambridge 1886. The Society. Florence:—R. Comitato Geologico d’Italia. JBollettino. Anno 1886. Nos. 9-10. 8vo. Roma 1886. The Committee. Geneva :—Institut National Genevois. Mémoires. Tome XVI. 1883-86. 4to. Genéve 1886. The Institute. Innsbruck :—Ferdinandeum fiir Tirol und Vorarlberg. Zeitschrift. Folge 3. Heft 30. 8vo. Innsbruck 1886; Fiihrer durch das Tiroler Landes-Museum. 12mo. Innsbruck 1886; Die Gemalde- Sammlung des Ferdinandeums. 12mo. Innsbruck 1886; Katalog der Germalde-Sammlung im Tiroler Landes- Museum. 12mo. Innsbruck 1886. The Ferdinandeum. London :—Quekett Microscopical Club. Journal. January, 1887. 8vo. London 1887. The Club. Royal Asiatic Society. Journal. Vol. XIX. Part 1. 8vo. London 1887. The Society. University of London. Accessions to the Library, 1876-86. 8vo. London 1886. The University. Vienna :—Zoologisch-Botanische Gesellschaft. | Verhandlungen. Bd. XXXVI. Heft 3-4. 8vo. Wien 1886. The Society. Zurich :—Naturforschende Gesellschaft. Vierteljahrschrift. Jahrg. XXX. Heft 1-4. 8vo. Zurich 1885; Jahrg. XXXI. Hett 1- 2. 8vo. Zurich 1886; Neujahrsblatt. LX XXVIII. 4to. Zurich 1885. The Society. Observations and Reports. International Polar Expeditions, 1882-83. Expédition Danoise. Observations faites 4 Godthaab. Tome II. Livr. 1. Ato. Copenhague 1886. The Meteorological Office. Kiel:—Commission zur Untersuchung der Deutschen Meere. Ergebnisse der Beobachtungsstationen. Jahrg. 1886. Heft 1-3, Obl. 4to. Berlin 1887. The Commission. Madras :—Meteorological Department, Government of India. Report. 1885-86. 8vo. Madras 1886. The Reporter. Paris :— Bureau International des Poids et Mesures. Travaux et Mémoires. Tome V. 4to. Paris 1886. The Bureau. Dépot des Cartes et Plans de la Marine. Annales Hydro- graphiques. 1886. Semestre 2. 8vo. Parts 1886. The Depot. 60 Presents. Observations, &c. (continued). Washington :—U. 8. Naval Observatory. Report, year ending June 1886. 8vo. Washington 1886. The Observatory. Journals. Astronomische Nachrichten. Band CXV. 4to. Kiel 1886. The Editor. Bullettino di Bibliografia e di Storia delle Scienze Matematiche e Fisiche. Hebei. 1886. 4to. Roma. The Prince Boncompaeni. Canadian Record of Science. Vol. II. No. 5. 8vo. Montreal 1887. Montreal Natural History Society. Horological Journal. Vol. XXIX. No. 341. 8vo. London 1887. The Horological Institute. | ileharols aisaha Zeitschrift. Jahrg. 3. Heft 12. Dezember, 1886. Small folio. Berlin. Meteorologische Centralanstalt, Vienna. Mittheilungen aus der Zoologischen Station zu Neapel. Band VII. Heft 1. 8vo. Berlin 1886. The Station. Naturalist (The) No. 138. 8vo. London 1887. ' The Editors. Revista de los Progressos de las Ciencias Exactas, Fisicas y Naturales. Tomo XXVII. Nos. 7-9; Tomo XXII. No.1. 8vo. Madrid 1886. Academia de Ciencias. Revista do Observatorio. Anno 1. Numero 12. 8vo. Rio de Janeiro 1886. The Imperial Observatory. Timehri. Journal of R. Agricultural and Commercial Society of British Guiana. Vol. IV. Parts 1-2; Vol. V. Partl. Svo. Demerara 1885-86. | Mr. E. F.im Thurn. Andrews (T.) Effect of Temperature on the Strength of Railway Axles. Part I. [In manuscript.] Folio. 1886; Volume of six excerpts on the Corrosion of Metals in Sea-water, &c. 8vo. 1875-85. The Author. Klein (Sydney T.) Hunting among the Lepidoptera and Hymen- optera of Middlesex. 8vo. Bath 1887. The Author. Mouchketow (J.) Turkestan: a Geological and Orographical Description from Data collected 1874-80 (Russ.). Vol. I. Part 1. Large 8vo. St. Petersburg 1886. Comité Géologique, St. Petersburg. Olsen (O. T.) The Fisherman’s Nautical Almanac. 1887. 8vo. Grimsby. The Author. Prince (C. L.) Observations upon the Climate of Uckfield, 1843-70. Second Hdition. 8vo. Lewes 1886. The Author. On the Computation of certain Harmonic Components. 61 “On the Computation of the Harmonic Components of a Series representing a Phenomenon recurring in Daily and Yearly Periods.” By Lieut.-General R. Stracuey, R.E., F.R.S. Received April 15,—Read May 13, 1886. Ie Following the notation commonly used, the general expression for the harmonic components of the successive terms of a series repre- senting a periodically recurring phenomenon, observed at equal intervals of time, is— An = Pot p; cos nz+q, sin nz+ py cos 2nz+ qo sin 2nz+ &e., where a, is the observed value of any term in question; zis the angular equivalent of the time interval between the observations ; , mis the number of intervals from the commencement of the period to the time when the term a, occurs; Po 18 the mean value of all the terms for the whole period. Then if A, represents the sum of the terms in the above series which involve nz, B, the sum of the terms involving 2nz, C, 35 Ms 3nz, XC., Computation fur a Daily Period. 9 For a daily period of 24 hourly intervals z = 15°, and consequently, An = Ae 5 Bn = Bayy = —Briys = —Baiis; C= Oe Eo —Cnis ee —Cnit2 = —Cri2; Di=Darss = Daye = Days = —Days =—Daso =—Dayis = Dyyar; whence, disregarding the terms involving multiples of z greater than 4nz, Ay = Gn—Onyiz = 2(An+Cn), and On = dn—An+at nag = 2(An—Antat Ansys) +2(Cu—Cuyat+ Cris) ; but 62 Lieut.-General Strachey. "On the An =P, on .15°) + 9, sin (n. 15°), Ansys = p cos (n.15°+ 60°) +4, sin (n. 15°+60°), Ansys = p, cos (n.15°+120°) +4, sin (vw. 15°+120°), and therefore An—AnptAnys = 0. Wherefore Oy = 2(Ca— Cua + Ongs) = 6Cn} and G.= 6, and An = 4dn—2On. In Jike manner, Sn = On+ Gnyiz = 2(o+ Br+D,), and Zn = Sn—Snis = 2(Br—Bnist Dr—Driys) = 4Bn; and B, =i%,, also on = Sat Snie = 2(po+Brt Brigt Dit Dnis) = 2(7)+2D,), and On43—= SnystSnys = 2(pyp—2Dn), whence Wn =n —On43 = 8Dn; and D, = >. The successive values of A, B, C, and D, thus obtained will give with a considerable degree of accuracy, the p q coefficients, and the entire series of harmonic components of the observed quantities. will at once be seen that— Ay =P; Bo = pes Co = P33 Do = Py: Ag=%3 By =; Co= 433 Di + De. = 2sin 60¢q, = Fq,, nearly. and = fy = 349— Go G1 = 34g + §%, Po = 4293 9 £23. D3 = §% =G(My—Ay +g) 5 U3 = Gq = F(Ap—Ag t+ Ayo). | Ps = 3(%—293) 5 Qs = a (o, + o,—2,—9;). J Computation of certain Harmonic Components. 63 3. The equations involving the harmonic coefficients, arising from the series of observed quantities, are usually solved according to the method of least squares; and, writing A, for (d,—d,,), and 6, for (d,+d,,), and so on, the resulting values of p q thus obtained are as follows :— py) = ts{do+ A, sin 75+ A, sin 60+ A, sin 45 +A, sin 30 +A, sin 15} Gy = ty{dgt 6, sin 15+4, sin 30 + é, sin 45+ 6, sin 60 +6, sin 75} Po = ts{ 2+ (2,—=;) sin 60+ (2,—2,) sin 30} | = 1{2,+ (2,+=,;) sin 30+ (2,+ =,) sin 60} a) P3 = 121% + (0; —43) sin 45 f | 93 = 1219+ (9, + 0s) sin 45} | Ps = ret Vot ie We) sin 80} | 4 = r2(¥1 t+ Yq) sin 60. J To these may be added Ps = tr{dy +A, sin 15—A, sin 60—A, sin 45 +A, sin 30 +A, sin 75}, = z;{d,+ 6, sin 75 + 6, sin 30—6; sin45— 6, sin 60 + 6,sin 15}, Pe = Tzi Zot =4— 9}; a= p=, —z g+z,}, id, —A, sin 15 —A, sin 60+ A, sin 45+ A, sin 30 —A, sin 75}, 97 = tz{—d,+ 8, sin 75—28, sin 30—6, sin 45 + 8, sin 60 +6, sin 15}, Ps = rz{ (+93) — (0, + 4) +04,4+26;) sin 30}, 9g = te {(o,+0,)—(oy+6;) } sin 60. 4, The values of the p q coefficients may, however, be obtained otherwise, in a form which is somewhat simpler for computation, and not sensibly less accurate. 64 Lieut.-Generai Strachey. On the Since An = p, cos n15°+q, sin n15°, Ay = Py and Ag = %: and putting [A,, A,] for the sum of the series of quantities A, to An, and [cos 75, cos 15] for the sum of cos 75+cos 60+ cos 45+ cos 15, it follows that [A,, A; | = p[cos 75°, cos 15°]+q,[sin 15°, sin 75°], [A,, Ay] = —p,[eos 15°, cos 75°] +q,[sin 75°, sin 15°], and | Ay+[A,, As]—-[Ay An] = p) {1+ 2[sin 15°, sin 75°]} = 7:°5956p,, A,+[A,, As|+[A,, Aq] = {1+ 2[sin 15°, sin 75°]} = 759569). In like manner, Bo+[B,+B,]—[B,+B,] = p,{1+2[sin 30+sin 60]! = 3°732p,, B,+[B,+B,]+[B,+B;] = qo{1+ 2[sin 30+sin 60]} = 3°732q0, Cot+C,—C3 = ps{1+2 sin 45°} = 2:4142p,, C,+C,4+C; = q3{14+2 sin 45°} = 2'41429., Do+ D,—D, = py{1+2 sin 30} = 2p, Di D, = ¢,.2sin 60 = 1-732l¢,. Substituting for A, B, C, D, their values in terms of d, A, 6, &c., we have— 7°5956p, = Hdy+[A,, As] +4(6)+0,—43)}, 7°5956q, = didgt Lo, 86] —3(O,+0,+ 95) }, 3°722p, =4{2)+[2,+2.]—[2,4+2;]}, 3°7329q, =F{2,4+[2,+2,]+[2,4+ =]}, 2'4142p, = 1{6)+0,—0,} = 42, 241429, = G10 +9, +93} = GB; 2D 4 = 31Yotvi-Veo}, 173219q, = sit ¥95- And Computation of certain Harmonic Components. 65 p; = 06583 {d)+[A,, A;]+3e}, q, = 06583 {dg+[6,, 6;]—gB}, Po = 06699{2)+[2,+>,]—[2.+ =; ]}; qo = (06699{S;+[2,+2.]+[2,+ =; ]}, + (3.) = -06904{0)+6,—0,t = -06904{[dy+A,]—[Ag, As]} =a, ks ie) | gz = (06904{0, +0,+ 43} = 06904{[6,, 6;]—[6;+4.]} = 8, Ps = te lVot Vi Yo} = 06251 vot Wy — Vo}; 4 = O7217 fy) + Yo}. J The expressions before given for pg, gg, and w., dg, are very readily computed, the multiplier for gg, 7; sin 60 = ‘07217, being the same as that for qy4. The computation of p,, q;, and p,, q7, may be rendered somewhat easier as follows :— (24, + Ay) +°102(A, +45)—py, By = te(2dy+ Ay) +°059(A] +2A;—A;) —p, | G5 = rz(2d5 + 62) +°102(6, + 65) —q; 9q = —Tz(2d_ +52) +°059(5, —28;—6;) + 9). 5. Assuming that the probable errors in the observed quantities are all equal, and that (e) represents the error in a pair of observations combined (corresponding to the quantities (d) and (s)), then the probable error of all the p, q coefficients calculated by the formule (2) will be 2, ./(6) .e = °204 e. The probable errors, calculated in the manner now proposed from equations (3), will be,— Probable error of p, or q, a 06583 / (12) . e = 238 e, My OG Goi== 400000 ./ (LO) se == “All aie: Ps, OF Ga = “O6904,/ (9)).e, = 207 e; ” Ps = 35/7 (12).e = 216¢e, ” V4 (O77 / (8) 6. =" 204e: _ VOL. XLII. F 66 - Lieut.-General Strachey. On the The results obtained by the two methods of calculation will there- fore have no sensible difference of accuracy, and as the method now proposed is believed to be both simpler and less liable to arithmetical error it may without objection be preferred. The preliminary com- putations on both systems, consisting of combinations of the observed quantities by addition and subtraction, are identical up to a certain point, but the formule (2) involve more frequent use of tables, and greater chance of error in algebraical signs, in the final operations. Tt may be added that much additional labour is often needlessly created by employing the hourly differences from the mean value, instead of the hourly vaiues themselves, which are obviously sufficient for the computation of the coefficients. The probable errors of the values of the coefficients obtained from the equations (1), will be sensibly larger than those above stated, and on the same assumptions will be as follows :-— For p, and ¢, = 4./(8) .e = ‘5/7e, »» p,and qo =Z/(2).¢ = 87le, 1» ps and g3 = 34/(8) 6 = 289e, » Pa = 7-e = *250e, » G4 =e. € —= 202e. The probable error of a pair of observations being rather less than 3ths of that of a single observation, the See possible error of the E oaercuts thus found will only be about 54,ths of the probable error of one of the original observations, and lion great precision is not aimed at the results thus obtained may suffice, and will not be found to differ materially from those got by the more tedious methods of calculation. 6. If the original expression for the value of a, is transformed into the series On = Pot Py (sin nz+T))+ P, (sin 2nz4+T,) + &e., it follows that P, = ./(p;?+q,"); tan T; = p,/q,, and so with all the other terms of the series. The most convenient method of computing the values of P, and T, is as follows :— log tan T = log p—log q; from this log sin T may at once be obtained, and log P = p—log sin T. Computation of certain Harmonic Components. 67 The quadrant to which the angle T belongs will depend on the algebraical signs of the coefficients p q, and the following table (in which ¢ is the angle corresponding to + p, +q) shows the cases that may arise. In it are also indicated the positions of the earliest maxima, p,, of the several harmonic components. | Position of earliest maximum of components. Value Coefficients. | and position ef TL. j : First order. | Second order. | Third order. | Fourth order. +p + q Sh Ly = 90° —¢ ho = 45° —3¢ v3 = 30°— at f4>= 224°— it 0° to 90° 0° to 90° 0° to 45° 0° to 80° 0° to 224°

-[B, to Bg] = p,[ cos 10° to. 80° ]—q,[ sin 10° to 80°] = 5° 21508(po+ 99), [ Byo to By] = 5°21503(—p.+ gq), | | [C, to C, ] = p,'cos 15" to 75° |— ga[sin. 15° to Vas io ee 93) [C, to Cy] = 3: 29788(—ps+4s), | [D, to D,] — [D, to Dz] = p,{1+ 2[ cos 20° to 80°]} = 575877 pa, [D, to Dg] = 2q,{sin 20° to 80°] = 5°67128q,. Computation of certain Harmonic Components. 71 Substituting for the quantities A, B, C, D, their values in terms of the series of 73 five-day means, we obtain after reduction the values of the p q coefficients. In the reduced expressions the following symbols are employed :— [(0) to (5)]-+[(67) to (72)] =, _ [(0) to (5)]—[(67) to (72) ]=Ay. [(6) to (8) ]+[(64) to (66)] = 2, Corresponding difference =A,, [(9) to (11)]+[(61) to (63)] = 3; ‘ : ae [(12) to (17)]+[(55) to (60)] = , . sah, [(18) to (23)]+[(49) to (54)] = 3; ft # fh [(24) to (26)]+[(46) to (45) ] = %, » =Ag [(27) to (29)]+[(48) to (49)] = 2, r ” =A, fey Ga) 70) to @2))= 2, °° 5 ae - [@) to (8)]+[(69) to (72)] = 3s, [(5) to (12)]+[(60) to (67)] = Xo, [(14) to (21)]+[(61) to (58)] = =n, [ (23) to (30)] +[ (42) to (49)] = yp, [ (82) to (35) ]+[(87) to (40) ] = 2). On = (n)+(72—N). Sn = (n)—(72—n). _ And let (3 (Ty) +T4)—$((0) + (72))) = then 45°80753p, = (1—7'z) {[ = to =,]—[%; to S33} +a(—o7 +308) ah ok ae 45°30753q, = (1—75){[A, to Ag]} —$é)—48, 45°72071p, = 1 —7s){ [222] [23 to =,]+ [272] } ; +8 {og —80g + 5¢9— 7597 + K + (86), 45-7207 19, = —ys){[A, to (A, to4dt 3 + 4{—o}7—26) +36) }. a=45°57452p5 = Owe 1s to B,]4. fs, to BSP +5 — %9 +30 47—50; + 76,—904g + 1loz)} + K— (86), es 7 5745295 = (1—+7;) {[A, to A3]—[A,A,]+ [Ag to Ag]} +§ {693 — 28); —36) +46}.—56,,}, azy _ Lieut.-General Strachey. On the 46-0701 6p = GQ 212,344 et +4 o,—3043+ 5Go9— 76a, $ +K+ me 49°370259, = (1—7y) {21 22] — [2324] + [2s26]-[2,28]} T+§1 — 696 + 2617 — 38g — 469 + 545 — 601g + 767}. The reciprocals of the numerical coefficients of the several p’s and q's in the above equations will be the multipliers of the quantities represented by the right-hand portions of those equations, which will be obtained by suitable combinations of the five-day means. The multipliers are— Horip, andy, -. 22. <2 02183 = m, Pps endl sn, ae on 02187 = m(1+:002), Peng eee. be Oe 02194 = m(1+-005), so i bea pl 02173 = m(1—-005), a nt ED 02204 = m(1-+-01). A table calculated to give multiples of the quantity -02183 will evidently suffice for the other coefficients, with the small corrections shown above. To provide for cases (which are likely to be frequent) in which the series of terms is not truly recurrent, corrections similar to those required for the 24-term series must be applied. As before, repre- senting by Ty) and T_, respectively the mean values for the first day of the period under computation, and the last day of the preceding year, and by 7) and ¢_, respectively the mean values for the first day of the following year and the last day of the year under computation ; the quantity that must be added to the first term of the series of 72 terms, corresponding to the initial midnight of the year, to make it equal to the first term of the next yearly series, will be 2c = 4(¢)+t_1) —4(T)+T_,), and it will be found that the corrections for the several p q coefficients will be as follows :— Hor py, . 2. 46% 9 == 70200 Borg, Cpe slac xa = 684c, » Po ---- oxm(1+002),| ., go --- el? ox mG +7002) eee 3 Pg --+- exml+'005),| ,, g,---- 11 cxm(14 005) aaa 9 Py os»! OX M(1—-005)2) 4,59, 2... ~8/ex mas 0D eee For pp, or the mean of the whole series,.... = 746. A similar method of computation might be adopted in the case of Computation of certain Harmonic Components. 73 a yearly period of 365 days, which could be transformed by interpola- tion into a series of 360 days, each term of which would correspond to 265 days = = 1+, days. But the irregularities of a series of daily quantities, in imeteavelbeical discussions, would be so great, even when dealing with the mean of many years, that no practical advantage would be obtained by employing such a series; the computations would be more troublesome, and the five-day means will be pre- ferable. 10. The annexed Forms are proposed as supplying methods of computa- tion from the formule contained in the foregoing discussion, which shall involve the least practicable quantity of arithmetical operations. Form 1 differs little from what is believed to be the ordinary method at present. It requires tables of multiples of the sines of 15°, 45°, 60° and 75°. Form 2 is for the proposed new method of computation. It requires tables of multiples of the special multipliers applicable to the several orders of harmonic coefficients. Form 38 requires no comment except to mention that the value of the angles which correspond to the hours of maximum y will facilitate the graphic representation of the several components, and appear to characterise them better than the angles T. Forms 4 and 5 call for no special remark. But they indicate the degree of divergence that exists between the approximate values of coefficients obtained from them, and those got by the more exact methods. The figures employed are the mean hourly temperatures for one year for the month of June, at Greenwich. If the mean values for a series of years had been dealt with, the results would not have differed one with another by so much as one-tenth of a degree Fahrenheit. Form 6 shows the method of computation from 73 five-day mean values. The figures employed are mean temperatures at Konigsberg for 24 years (taken from Bessel’s paper, the translation of which is given in the ‘ Quarterly Weather Report’ of the Meteorological Office, Part IV, 1870, page [29]), which were selected in order to test the agreement of the results with those given by Bessel, calculated by the method of least squares. The values of the coefficients by the two methods are virtually identical with the exception of p3, in which I feel satisfied that some error has been committed in Bessel’s calcu- lation; to verify this, however, would involve a very tedious com- putation which I have not thought it worth while to undertake. It should be observed that Bessel’s coefficients, being calculated with reference to a period commencing with the first of the five-day means, that is noon on the 3rd day of the year, have to be modified to adjust 74 - Lieut.-General Strachey. On the them toa period commencing with the initial midnight of the year. © In order to render the form complete, as a type of the proposed system of computation, values for the first and last days of the year have been interpolated, and a small non-periodical correction has been assumed to be required; but these have no practical effect on the numerical results, For this computation a table of multiples of the multiplier (m) is’ required, and to save trouble a table of multiples of ;, has also been drawn out. Nots.—The Tables referred to will be printed by the Meteorological Office. | £g.t9 PI.0+] 91.0—|19.04+|4£.04+|b0.0+|99.0+|60.b—|1¢.Z—| °° @ereen08 pearson Components. 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L—| zitihzi+izy +) $S1—| 6.z/ S.4S | eT-¢ 1Z.0+| 19.0+] 9£.04+] 9f.9— ov.o+] 91+ | got | 4z.g—| 49. —| 09.4—] ob +|16 4/56 +] zS1-| 0.€4 | g.ZS | ET-g 40.0—| 69.0+]| gS.0+4+]| z1.9— zS.O4+] 12+ | 60f1 | or.g—| $4. —| SE.L—| Sh+|sq 4/4z14+] LZbr1—| g.zZ | 3.99 €1-1 91.0—| oF.0+4+] S9.04+] 1€,L— Sg.O+/ E+ | Er€r | dz.4—| zh. —| Sg.g—| Szt+lyr +]obr+| Ze1—| S.zZ | 9.95 | gt-o (al ‘0 a ‘Vv SG 09. CT | T1990 7 Gp Pose oe pe ee oe | ‘syuotoyjoon ‘b ‘d ayy Jo sontea a az 8 ‘Vv Oa Pp 0 Bee ee : poe worZ poyndutos syuouodutog i ee a) eee ed = ee eee ‘SLOPIQ INOT FSI Ot} FO syueuodmoy oruowmaepy fo sonteA oyeurxorddy jo uoyeyndmog—y, wmu0,7 for a Series of 73 Five-Day Me ined half- Sums and differences | s’ sums. of half-years’ sums of terms. | 4 and 8 terms. | Sums. /|Differences. } ie >. A. | — 1433 | | — 1085 |— 2518 - A — ele >|) a 3320 |) = 740 |: Bi bs) | is oe a) aE ee | Ve OG — 1069 Cc < | eae, Oa a me OLE 27rh 1287 D J +1238/-— 463 * EB — re | GON | ae PRS F | Form 6,—Computation of the Harmonic Coefficients of the First Four Orders for a Series of 73 Five-Day Means. j Part IL (add to Part I). ; : Partial sums of Combined half- Sums and differences Part I. Five-day means. terms. years’ sums. of half-years’ sums of =i terms. Combined multiples of differences. | Pairs of terms. Dim Combined differences of half-year’s terms. Term. | 18 half- 2nd half-},,,_, | 1st half /2nd half- gente aes = se pple t year. 3 ear. ear. D erms. ums. oS. Term, vio | qo Ta | Us | Sums. [Ditferences.| year. year. y J erence: a | ae | de | wi | o. 6. | 4. | | O |-1| +0’41 |-2] + 0°82 |-3)} + 1°23 |—4 | + 1°64 | — 7°67 | —0°41 O j= 4°04 |— 3°63 | 72 B + |— 740] + |— 7°40} + j— 7-40] + |— 7°40 8 —3 | +13°23 * * 1 4°12 2°34.| 71 Cc + |—10°69 | + |—10°69 | + |—10°69 | + |—10°69 9 +5 | —1B-45 * * 2 3°72 3°09 | 70 1433 D + J—12°87 | + [—12°87 | + [—12°87 | — |+12°87 1 —2| + 9'08 « * 3 2°45 1°79 | 69 | —1433 | —1085 — 1085 |— 2518 = Ay} FB | + [32°85 | + |—32°85 | — j432°85 | — |+32°85 12 +4 | —16'24 = —— —S= —|—} H | + |—29°95 | — |+29°95 | — |+329°95 | + |—29"95 if —1]| + 6709 +2 | —12°18 | — 4°57 * 4 3°36|— 121 | 68 | — 336] — 121 — 2030 I + |—13°09 | — |+13'09 | + |—13°09 | + |—13°09 18 +3 | —16°Sy —6 | +3318 ——— == K + J—11°93 | — [+1193 | # [—I1'y3 | — | +11'93 28 +1) — 4°50 = 3°45 id 5 2°61 |— 0°84) 67 | — 261 | — 084 |) —x290 — 3320) — 740 | BY N | + |=15c15 | = |+15°35)| # [StS 15) — |e rsors bn -—5 | +2290 3 = (Sy a =e = S| = eee a 2 —l | + 4°02 |r 2°17 |+ 0°20 + + q7o*r2 | + 2°80} + 2°80 27 ey Sapte * af * 7 3°09 |+ 0°82] 65 a 847 Sum}, = = 63°81 | _= Is | — 61°13 — | —-— | — |} —- -— — | — — = 2°01 4°41 8 3 ‘21 1°20 | 64 | — 847 | + 222 + 222 = 625 | —r1069 | ¢ |——|——— — — | ————. cinco? + 6°91 | + agar |) ep 52°07 = == |__| ==) PISRCOgr bets (eb e }h 8°33 | + | 11°67 = i) Tso 204 | = Brag Roe one 3.. 69 9 2-21 | 1748] 63 | — ts r 9°09 ola O15 SS oo — aa * * 10 1°74 | 2°90] 62 — 521 ——|—_ |} — | — | —_— | | —— + 2) +041 4) — 9°68) 6) +12°47) 8'— 6'42 * 4°54 11 1°26 ciety tail jp rye J ae at qe Bis Tie 2460) — 3207 | — || 13207 || + 6°22 | — Scar] + 11'53 = p= ee = ee ee eos | a ——| Pé2} + o°2ar}| — 2°42 | + 2°08 | — "80 + 0°21 = 242) + 2°08 — 080 * — 4°06 12 |— 0°72 3°34] 60 | — 072 | + 334 J +1238/— 463 = EB er ss oe 5a Se | el |e ee a oe ees ne, ————e ——| — | 13186] + 3°80 | — 6°13 | + 10*72 7 + 3°43 * 13 |— 112 4°55] 69 | — 112] + 455 —&} + 2 'O4 8 * % 14 |— o'11 5°47 | 58 — | 129°82 * * 15 |+ 0°05 5°50 | 57 oe re eee | eee a SS | a * * 16 |— 02 5°75 | 56 — 135 Tab. —2°84 +0°08 =O'13 +o'2 7°69 | —6'09 17 |+ 0°80 6°89 | 55 | + ogg | +2361 cee +3015 | —3285 | BF | Corr. +008 +0°O4 +0°03 +o'o2 = + 9°03 | —5°53 18 {+ 1°75 7°28 | 54 jh Mm | —2°76| ga | to't2 | gg} —o'ro | gy] +0'2 * * 19 3 ‘02 8°48 | 53 Combined multiples of sums of terms. * * 20 3°95 8°82 | 52 * * 21 4°96 9°46 | 51 +1368 | +3404 Perm Pi Px Pa Pw +15 °83 * 22 5°37 | 10°46 | 50 + 537 |_.+1046 +2517 Aaa ee, | fi ee ee Pa 4 +1li]— 4°57 * —4'50 23 6°12 | 10°62 | 49 + 612 | +1062 2 +5512 + 8029 5 —5 |+ 17°25 — | '—_—_ — ——_|—_—-_—__|—_| A * « bd + |— 25°18 6 +7 |— 13°79 * —4'58 24) 7°40 11‘y8 48 B + |— 33°20] + |— 33°20] + |= 33 ‘ac} * 8 —3/+ 6°03 * * 25 7°93 12°42 | 47 +2387 OC + |— 6°25] + |— 6'as] — | Gras] # 9 +5 1/— 3°65 #21'to | —4'02 26 854 | 12°56] 46 2387 al Bsrel/9§ + 6083 | — 1309 I D + [+ 2'45] — |— 2°46) — [= sys] * 13 -3 |= 10°29 — + — —| BE . * * —]+ 4°63 VW |=-1) — 7°69 +3 [+ 23°07 +23 ‘06 | —3°98 27 97°54.| 13°52 | 45 ay + |+ 30°15) — |— 30°15] — |— 30's) * 18 |4+3) +27 ‘09 —9 |-- 81°27 | . * 28 9°75] 13°76] 4h +2936 qa | * * £ + [+ 71°82 22 +5 |+ 79°15 | +2408 * 29) 10°07 14 ‘OI 43 +2936 | +4129 Pe) +6968 |+ 7065 —1193 K i — |— 80'29| — |— 80°29] + | + Boag) * 26 +1j]+ 21'Ilo —___—_|_— —| I | — |= 60°83} — |— 60°83) + |+ 60°83) * 27 —7 |—161 "42 +2445 * 30 10°33 | 14712 | 42 | +1033 | +1412 |) J) +10299| + 17267 = L K | — |= 70°65] + |+ 70°65] + |+ 70°65) * 29 — 1— 24°08 ———— —=— ——- ae a —|—| L * * be — |—172'67 80 +11) + 268 “95 +25 °71 * 31 Ir*so} qt21 | 41 | +1150 | +1421 M * * * + |+100°51 BL —7 |-179'97 ————— — | —_——_|____ N | — |—150°67] + |—150°67) — |—150°67| * eee ere es | eres | ceeens SS SP * * 32 1I “41 14°04 | 40 — ——} ba) eee Pee mee Sim + 27°13 | + | 309°27 | + 79°15 * * 83 11‘oz | 13° 39 +4593 Sum | * 32°60] + | 221°32] + | 218 ‘o2} + | 176'96 - 165‘07 | — lig'lg | — 194°83 * * 34 I1“45 | 13°64} 88 +6756 | ( +5458 |+ 10051 * M — | 40189] — | 213°17] — | 215'47 197 85 eb ee bam * * 35 |+12°05 |+13°63 | 37 +4593 | +5458 J +8291 |} — |—_—— —— — a + 4 | +19°40) 8 |—137'94 | 12 |+190°13 | 8 |—115 °68 — — , ——. ———— | +15067 | —1515 N - 369°29) + 815) + 1°55) — 20 ‘8g — | | 2 |e a 86 |+12°73 a De zy —| —y5 5°13 "Ir ‘oa "ag + 4°85 — 17°24 + 15°84 — 14°46 —— +36 +1273 — — oo =a (86) - 12°73] + 1a'73 | = 12°73 | + 12°73 Mean, 81st Dec. sues —4700 ———" — | 364°16) + om + 1°53] = 20 *60) _—_—o—— OO J » Ist Jan. To =4°'02 —8'02 165 Ppé2}] — on] — 4°68) + 2'94) — 1°90) — 7°88 = 451 + 3crr — 1°73 sum oan _——— -| |__| —|— — |. ws = 0°17 =" 0) r7 — o'l7 — o'l7 Mean, 31st Dee. ty —3°74 — | 372°a! sao + 4°47 — 22'50 —— | — | — sj —= 5 Ist Jan, to —3°80 7°54 +73 36832 +5 + 1°49 a = 8°05 — 4°68 + 2°94 = 1°90 aera 3(T_, + T,) v —4'Or Mean | +5 ‘o4s5 - 370°72 >: areas << - = . (t+ f) y etry / =s rae ae ar ae ae = See, 4(0 +72) Po —3°84 a x Tab. —8 ‘og + 0'0o7 + 0°!) l—-o'49 Non-periodie correction. a peat | Ok, Corr. ° ° ° | o | FO'24 es att Eee | h: he Bose Pi| —8"09| Pa | 0°07) ps} t+ 010) Pa |- O49 * “oc “(94 I Qn . . aa —a oe .- OC*~«~<(—stété«s«S «CO ee oes peak pa gyi WE He eae ue ‘The quantities in the line marked “Tab.” are found in the Tag Ae PA aa 14-04 [4 "03 \* a tables of multiples of (m) from the figures in the line imme- diately above. oF cate GW oes vere 79 ac Components. in Harmon Computation of certa ore ke td P.o+ Ps ae 8.95 ce sf SECS LACT 2 ob + = Gz + 9+ % 16 + I, 09 lee JOSS i ( SS ee eee g. 69 L6 + Oly + gi + 8p + L6z1 % g. 19 I. 89 ee se EES C6 + %) — gti + tp — % 91 + g.£9 v.59 SILO OHO 5, Se Sm OP ae 2 * x 7.99 Se ee acs 2) Z.0+ ed 8.0+ 6Lz1 $6 — | 4.39 OE} a Cet DT 0 L + FF be + P+ se aes t.of beled SES IONE L671 6a — 6L71 Ig — s Orr 6.1L Calg OO 3 bott eg Cr¢y 0 oF! ‘ 6227 Gans OEY Hae Id oo b= % (OT Oee BLS ae er L.0+ fh+ 4.0— td — se a Ree 1. 9S We ole vii g.7— 9p 6.9— Oz C11 Lei— g.%h 8.89 ei) "SS (99 GT “TT 940 *b “a "stung "SOOUCKO RUC) | aso —— re TOF, "paatesqoO ‘SIOPIO, 9014], WAT 944 FO S}UeTOMJeoR oruomAePY 044 JO sone ojeurxoaddy jo uoyegndmo0g—‘¢ w40g VOL. XLII. 80 Sir W. Thomson. On the . [Feb. 3, February 3, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On the Waves produced by a Single Impulse in Water of any Depth, or in a Dispersive Medium.” By Si W. THomson, Knt., LL.D., F.R.S. Received January 26, 1887. For brevity and simplicity consider only the case of two-dimensional motion. All that it is necessary to know of the medium is the relation between the wave-velocity and the wave-length of an endless proces- sion of periodic waves. The result of our work will show us that the velocity of progress of a zero, or maximum, or minimum, in any part of a varying group of waves, is equal to the velocity of progress of periodic waves of wave-length equal to a certain length, which may be defined as the wave-length in the neighbourhood of the particular point looked to in the group (a length which will generally be inter- mediate between the distances from the point considered to its next-neighbour corresponding points on its two sides). Let f(mv) denote the velocity of propagation corresponding to wave- length 27/. The Fourier-Cauchy-Poisson synthesis gives u=[dmecosmle—tf(m)] Ms - AND for the effect at place and time (a, ¢) of an infinitely intense disturb- ance at place and time (0,0). ‘The principle of interference as set forth by Prof. Stokes and Lord Rayleigh in their theory of group- velocity and wave-velocity suggests the following treatment for this integra] :— When «—?#f(m) is very large, the parts of the integral (1) which lie on the two sides of a small range, w—« to w+a, vanish by annulling interference ; »« being a value, or the value, of m, which makes {mle—tfm)}}=0; 2... . @) 1887.] Waves produced by a Single Impulse. 81 so that we have Batt ia egy ly sD i 220) where Wa TC Se ee el es sD and we have by Taylor’s theorem for m—y very small : mle—tf(m) | = wle—tf(H)|—stlef'() +2f'()](m—p)*, - (A) or, modifying by (3) mla—t fim) | = Hef (eH) +al—ef () —2f'() ]m—w)?f- + (6) a ae Or Cy and using the result in (1), we find _ A2 fideo cos [tu f (wu) + or es Haro —wF Fo the limits of the integral being here —co to co, because the denomi- nator of (7) is so infinitely great that, though +a, the arbitrary limits of m—w, are infinitely small, «2 multiplied by it is infinitely great. Now wehave ff decoso*=/f dosine®? = J/(g7). . . - (9) Hence (8) becomes __ cos [én?f (w)]—sin [tof (w)] _ _/2.008 [tp (uw) +30] nf’ @- FOE AH eF'W—2 WE To prove the law of wave-length and wave-velocity for any point of the group, remark that, by (3) twf (wu) = wLae—tf(e)], and therefore the numerator of (10) is equal to ./2 cos 0, where Omit im) |\-pta) s e EO (10) ¢ ( ad and by (2) and (8) F{ule—t/(w) ]} <0: by which we see that dojdei =p, and do/di=—pf(m), .-. . . (10") which proves the proposition. * This is the group-velocity according to Lord Rayleigh’s generalisation of Prof. Stokes’s original result. Ea7 82 Sir W. Thomson. On the [Feb. 3, Example (1).—As a first example take deep-sea waves; we have f(m) = / = PPT! Fl nc (11) which reduces (4), (3), and (10) to y=ta/h —— ll and aay /L-t, . . . 1 t gt® gt? 3 gt? T 23 as ae 14) i g/2 23 (cos Aa Te Ax ge at Awe Au a oe which is Cauchy and Poisson’s result for places where x is very great: in comparison with the wave-length 27/,, that is to say, for place and. time such that gt?/4e is very large. Example (2).— Waves in water of depth D: I) Ge th ee oo : Ezample (3).—Light in a dispersive medium. Eaample (4).—Capillary gravitational waves : jn) = 4/(L+0m). a Example (5).—Capillary waves : fm=J/&n). . re Example (6).—Waves of flexure running along a uniform elastic rod: Fm) =m 4 / =, ll where B denotes the flexural rigidity, and w the mass per unit of length. These last three examples have been taken by Lord Rayleigh as applications of his generalisation of the theory of group-velocity ; and he has pointed out in his “Standing Waves in Running Water” {London Mathematical Society, December 13, 1883) the important peculiarity of Example (4) in respect to the critical wave-length which gives minimum wave-velocity, and therefore group-velocity equal to wave-velocity. The working out of our present problem for this case, or any case in which there are either minimums or maximums, or both maximums and minimums, of wave-velocity, is particularly interest- 1887. ] Formation of Coreless Vortices in a Fluid. 83 ing, but time does not permit its being included in the present com- munication. For Examples (5) and (6) the denominator of (10) is imaginary ; and the proper modification, from (7) forwards, gives for these and such cases, instead of (14), the following :— = C8 Lief) +sin [FI ne Gr Ap (a) eri a The result is easily written down for each of the two last cases { Hxamples (5) and (6) ]. (19) II. “Qn the Formation of Coreless Vortices by the Motion of a Solid through an inviscid incompressible Fluid.” By Sir W. Tuomson, Knt., LL.D., F.R.S. Received February 1, 1887. Take the simplest case: let the moving solid be a globe, and let the fluid be of infinite extent in all directions. Let its pressure be of any given value, P, at infinite distances from the globe, and let the globe be kept moving with a given constant velocity, V. If the fluid keeps everywhere in contact with the globe, its velocity relatively to the globe at the equator (which is the place of greatest relative velocity) is 2V. Hence, unless P>2V*,* the fluid will not remain in contact with the globe. ‘Suppose, in the first place, P to have been >2V2, and to be suddenly reduced to some constant value <£V*. The fluid will be thrown off the globe at a belt of a certain breadth, and a violently disturbed motion will ensue. ‘To describe it, it will be convenient to speak of velocities and motions relative to the globe. The fluid must, as indicated by the arrow-heads in fig. 1, flow partly backwards and partly forwards, at the place, I, where it impinges on the globe, after having shot off at a tangent at A. The back-flow along the belt that had been bared must bring to H some fluid; and the free surface of this fluid must collide with the surface of the fluid leaving the globe at A. It might be supposed that the result of this collision would be a “‘ vortex sheet,” which in virtue of its instability, would get drawn out and mixed up indefinitely, and be carried away by the fluid farther and farther from the globe. A definite amount of kinetic energy would be practically annulled in a manner which I hope to explain in an early communication to the Royal Society of Hdinburgh. But it is impossible, either in our ideal inviscid incompressible * The density of the fluid is taken as unity. 84 Sir W. Thomson. On the [Feb. 3, Fig. 1. fluid, or in a real fluid such as water or air, to form a vortex sheet, that is to say an interface of finite slip by any natural action. What happens in the case at present under consideration, and in every real and imaginable case of two portions of liquid meeting one another, as for instance a drop of rain falling directly or obliquely on a horizontal surface of still water, is that continuity and the law of continuous fluid motion become established at the instant of first contact between two points, or between two lines in a class of cases of ideal symmetry to which our present subject belongs. An inevitable result of the separation of the liquid from the solid, whether our supposed globe or any other figure perfectly symmetrical round an axis and moving exactly in the line of the axis, is that two circles of the freed liquid surface come into contact and initiate in an instant the enclosure of two rings of vacuum (G and H in fig. 2, which, however, may be enormously far from like the true configura- tion). The “circulation” (line-integral of tangential component velocity round any endless curve encircling the ring, as a ring on a ring, or one of two rings linked together) is determinate for each of these vacuum-rings, and remains constant for ever after: unless it divides 1887. | Formation of Coreless Vortices in a Fluid. 85 bie. .2. itself into two or more, or the two first formed unite into one, against which accidents there is no security. It is conceivably possible* that a coreless ring vortex, with irrota- tional circulation round its hollow, shall be left oscillating in the neighbourhood of the equator of the globe; provided (8V?—P)/P be not too great. If the material of the globe be viscously elastic, the vortex settles to a steady position round the equator, in a shape perfectly symmetrical on the two sides of the equatoreal plane ; and the whole motion goes on steadily henceforth for ever. If (¢V*—P)/P exceed a certain limit, I suppose coreless vortices will be successively formed and shed off behind the globe in its motion through the fluid, incessantly. * Tf this conceivable possibility be impossible for a globe, it is certainly possible for some classes of prolate figures of revolution. 86 Presents. [Feb. 3, II. “On Proterosaurus Speneri (von Meyer).” By sna. SEELEY, F.R.S., Professor of Geography in King’s College, London. Received February 3, 1887. (Abstract. ) The author gives an account of the scientific history of Protero- saurus, and states the interpretations of its structure given by Cuvier, von Meyer, Sir R. Owen, and Professor Huxley. _ In Part II he describes the type specimen in the Museum of the Royal College of Surgeons. In the skull characters are given of the cerebral cavity, the supra-occipital, parietal, frontal, pre-frontal, nasal, and premaxillary bones. A restoration is made of the skull and the teeth are shown to be anchylosed to the jaw. On the palate the vomer, palatine, and pterygoid bones are described and shown to have all been armed with minute teeth. The pterygoid bone was strongly united to the quadrate bone. The lower jaw and hyoid bones are also described. In the vertebral column a description is given of the second to the seventh cervical vertebra, of sixteen dorsal vertebre, two sacral vertebrz, and twenty-three caudal vertebre. ~ The femur, tibia and fibula and foot are also described. The skin is found to have been defended with a bony armour. In Part III comparison is made between the type and other _ specimens which have been referred to it, with the result that some are regarded as indicating different species while others indicate different genera. In Part IV a comparison is ‘aadle to show the resemblances of Proterosaurus with other reptiles, in the several regions of the skeleton; with the result that the Proterosauria is regarded as a distinct division of the Reptilia, showing resemblances to many of the highly specialised orders and to some low types. Presents, February 3, 1887. Transactions. pa Baltimore :—Johns Hopkins University. Studies in Historical and Political Science. Fifth Series. Nos. 1-2. 8vo. Baltimore 1887. The University. Christiania :—University. Om Humanisten og Satirikeren Johan Lauremberg. 8vo. Christiania 1884; Antinoos, eine Kunst- archaologische Untersuchung. 8vo. Christiania 1884; Lakis Kratere og Lavastromme. 4to. Kristiania 1886; Norges Vaext- rige. Bind I. 4to. Christiania 1885. The University. SA 1887. | Presents. 87 Transactions (continued). Hastbourne :—Natural History Society. Transactions. Vol. I. Parts 9-10. 8vo. Hastbourne 1885-86. The Society. London :—Sanitary Institute. Transactions. Vol. VII. 8vo. London 1886. The Institute. Paris :—Ecole Normale Supérieure. Annales. Année 1887. No. 1. 4to. Paris. The School. Pesth :—Magyar Tudomdnyos Académia. Almanach, 1885 ; Archzo- logiai Ertesitd. 1884, Kétet IV. 1885, Kétet V. Szdm 1-2; Bulletin, 1884-85, 1-3 ; Emlékbeszédek. Kotet IL. Szam 3-10. Kotet III. Szim 1-2; Ertekezések (Nemzetgazdasgi). Kotet II. Szdm 6; Ertekezések (Nyelvtudomanyi). Kotet XI. Szim 11-12. Kétet XII. Szim 1-5;. Ertekezések (Mathe- matikai), Kétet XI. Sz4m 1-9; Ertekezések (Tarsadalmi). Kotet VII. Szam 8-9; Birtekezések (Természettudomanyi). . Kotet XIV. Szam 1-8; Ertekezések (Torténettudomanyi). Kétet XI. Szdm 7-10. Kotet XII. Szim 1-2, 4; Evkonyv. 1884. Vol. 2; Evkényvei. Kétet XVII. No. 2; Légtiineti Eszleletek. Ratot II; Mathematikai és Rorinean Ertesité. Kotet III. Fiizet Hy. Mathematikai és Termész. Kozle- mények. Kotet XVIII. Kotet XIX; Mathematische und Naturwissenschaftliche Berichte. Bd. Il; Nyelvtudomanyi Kozlemények. Kotet XVIII. Fiizet 2-3. Kotet XIX. Fizet 1 ; Repertorium. Kétet I. Resz 1; Ungarische Revue. 1885. Heft 1-7; Ertesitdje. Kétet XVIII. Sz4m 3-7. Kotet XIX. Szam 1-2; Konig: Egyenletek. 8vo. Budapest 1885; Als0- Magyar. banyamtivelésének torténete. Kotet I. 8vo. Budapest 1884; Régi Magyar Konyvtar. Kotet I]. 8vo. Budapest 1885 ; Bartfai Konyvtar. 8vo. Budapest 1885; Vazlaték az Akadeé- mia. 1831-81. 8vo. Budapest 1881 ; Mag gyarorszag II. Joézsef Koraban II. 8vo. Budapest 1884; Monumenta Comitiorum | Transsylvanie. Kotet X. 8vo. Bidanest 1884; Monumenta Hungarie. Kotet I. 8vo. Budapest 1885; Nyelvemléktar. Kotet XI. Koétet XII. 8vo. Budapest 1884; Codex Diplo- maticus. Kotet IV. 8vo. Budapest 1884; Bethlen és a svéd Diplomatia. 8vo. Budapest 1882; Aimilius Papinianus. 8vo. Budapest 1884; A Kereszténység fondamentomardl. 12mo; Hpistole Sancti Pauli. 12mo; A Keszthelyi Sirmezok. 4to. Budapest 1884. The Academy. Trondhjem :—K. N. Videnskabers Selskab. Skrifter. 1885. 8vo. Trondhjem 1886. The Society. Observations and Reports. Christiania :—Fjerde Beretning om Bygde Kongsgaard med Tilleg. 4to. Christiania 1886. The University, Christiania. 88 Presents. [Feb. 3, Observations, &c. (continued). London:—Kew Gardens. Bulletin of Miscellaneous Information. No. 1. 8vo. London 1887. The Director. Meteorological Office. Weekly Weather Report. Nos. 42-52. 4to. Quarterly Summary of Weekly Report. Third Quarter, 1886. 4to.; Monthly Weather Report. July-August, 1886. 4to. The Office. Melbourne :—Department of Mines. Reports of the Mining Registrars, quarter ended September, 1886. Folio. Melbourne 1886. The Department. Observatory. Observations of the Southern Nebule made with the Great Melbourne Telescope, 1869-85. Part I. Folio. Melbourne 1885. The Government Astronomer. Montreal :—Geological and Natural History Survey of Canada. Annual Report. 1885. With Maps. 8vo. Montreal 1886. The Survey. Pesth :—Konig. Ung. Geologische Anstalt. Die Kon. Ung. Geo- logische Anstalt und deren Ausstellungs-Objecte, &c. 8vo. Budapest 1885; Foldtani Intézet es ennek Kidllitasi Targyai. Svo. Budapest 1885; Special-Katalog der VI-ten Gruppe. 8vo. Budapest 1885; Der Goldbergbau Siebenbirgens. 8vo. Buda- pest 1885. With six other pamphlets in 8vo. The Institution. 1887.] Contributions to the Metallurgy of Bismuth. 89 February 10, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “Contributions to the Metallurgy of Bismuth.” By EpwaRp MArTtTuHey, F.S.A., F.C.S., Assoc. Roy. Sch. Mines. Commu- nicated by JOHN PrErcy, M.D., F.R.S., Pres. Iron and Steel Inst. Received August 18, 1886. § 1. Bismuth: its Separation from Gold, and its Refining Action upon same during the Process of SeparationIn bringing the above subject under notice, it is necessary to allude to some of the facts dis- tinguishing this very interesting metal. Bismuth, in some of its important characteristics and reactions, resembles lead. And one of the chief points of resemblance between these metals is their ready oxidation, and their absorption by bone- ashes or wood-ashes whilst so oxydised. I refer of course, to the process of cupellation. This ancient and serviceable process, still employed universally for the separation of gold and silver from lead, is equally applicable to bismuth, if associated with these precious metals; and, like lead, bismuth may be readily employed as a vehicle or means of collecting gold and silver from their ores in reduction processes; but its com- | parative cost accounts for its non-employment in this respect. Commercially speaking, bismuth differs from lead in its greater value, lead being worth at present £13 to £14 per ton,* whilst bismuth realises between £700 and £800 per ton ; this high value being due to its greater rarity and to its limited and special uses. As is well known, bismuth ores are frequently auriferous; and one of the points which it is my desire to bring under notice is the effectual separation of the gold from bismuth by a rapid and effica- cious process. Of course, nothing could be easier than to separate these two metals by the ordinary process of cupellation. The gold, by these * June, 1886. 90 Mr. E. Matthey. [Feb. 10, means, is at once rendered available, but with the drawback that not only is there a very considerable loss of bismuth by volatilisation during the cupellation, but the subsequent recovery of the metal, which in the state of oxide has been absorbed by the cupel, is rendered necessary, involving a tedious and troublesome smelting operation, the employment of expensive fluxes, and a further con- siderable loss of metal. Bearing in mind the close resemblance of bismuth to lead in its behaviour in the cupellation process, I directed my attention to its separation from gold by means of the addition of a small proportion of zinc—a method known as the Parkes process, as employed for the separation of silver from lead. And this I found successful, the natural separation of these two metals during the process of cooling proving to be similar in both cases. The operation as carried out by me is as follows :— The Bismuth holding the gold is melted at the ordinary tempera- ture, about two per cent. of melted zinc is then added, and the whole brought to a dull red heat. The alloy is then well stirred. and the temperature gradually lowered. When at a black heat the sight crust formed on the surface is skimmed off and the metal again treated with a further quantity of zinc at the higher tempera- ture. The whole of the gold will be found in these skimmings, and the bismuth will be thus freed from it. The skimmings, consisting of bismuth, gold and zinc, and zine oxide, I now treat by a process which quickly renders the gold avail- able, and at the same time has the effect of refining the gold from all impurities excepting silver during the actual process of extraction. This small proportion of bismuth litharge and its charge of gold is fused in a clay crucible with a little borax, and allowed to cool down in the crucible, or it is poured into a mould with the bismuth litharge, which being perfectly liquid, allows the metallic gold to separate by its own gravity, and during its fusion absorbs any base metals associated with it as oxides. The bismuth litharge, in fact, acts as a refining agent to the gold, which, when cold, is_detached from it. This bismuth slag is broken up, re-fused with a little metallic bismuth, and is so freed from the last trace of gold which is collected by the bismuth, and subsequently extracted. The bismuth litharge so freed from gold is then reduced by fusion with carbon to its metallic state. The quantity of bismuth litharge holding the gold is exceedingly small in proportion to the bulk of metal originally treated, as the figures hereinafter given will show ; but, by this process the bismuth is at once freed from its gold contents with little time, labour, or expense. I have continuously carried out this method of treatment with the 1887. ] Contributions to the Metallurgy of Bismuth. 91 most satisfactory results. It will only be necessary to take the figures of one operation as an illustration. A quantity of 9483 lbs. of bismuth, holding about one per cent. of impurity, and 12°5 ounces of gold per ton (equal to 53°5 ounces in the bulk), was so treated, and of this nearly 9000 lbs. was imme- diately rendered available for commercial use, the skimmings, which amounted to 658 Ibs. (7:30 per cent. of the bulk), containing the whole of the gold. These skimmings I oxidised by means of nitric acid, thus obtain- ing the greater proportion of the bismuth and what little copper there was in solution, from which the bismuth was precipitated by the ordinary method, care being taken to saturate the nitric acid by ex- tracting the greater portion of the bismuth as nitrate, so as to leave a portion of the bismuth as oxide with the gold in order to refine it from the impurities existing as oxides when fused with it. This residue, collected and dried, was, when dried, fused in clay crucibles, with a small quantity of borax, yielding the full amount of gold shown by assay. As before stated, in these fusions the metallic gold separates from the bismuth litharges, and descends to the bottom of the crucible by its own gravity. The liquid and supernatant bismuth litharge floats upon it and breaks away readily when cold, the gold so obtained being associated only with silver, both metals being in fact refined by the action of the bismuth litharge. § 2. Separation of Bismuth from Lead.— The difficulty surrounding the treatment of bismuth associated with other metals by any rapid or comprehensive process is well known to the metallurgical chemist. I believe I am correct in stating that hitherto the only process employed for the refining of bismuth on the Continent—notably in Saxony, the chief continental source of this metal—has been that of chlorination and subsequent precipitation, a process tedious in itself and involving much plant and labour in comparison with the quanti- ties of metal operated upon. Rapidity of production with a minimum margin of loss, in order to free the metal from its impurities and render it marketable as quickly as possible, being a great desideratum, induced me to turn my attention to its refining by dry processes. In carrying this out I have found present most of the metals which are easily seized by and become associated with the bismuth itself during the process of reduc- tion from its ores,* such as antimony, arsenic, tellurium, lead, copper, &e., &e., all of which I have successively and successfully dealt with. Ié is not my intention in this paper to describe the processes adopted for the elimination of these several metals, but to confine * See Table of Analyses herewith. HE Mr. EK. Matthey. [Feb. 10, myself to the separation of lead, the presence of which especially presented at first great difficulties. As stated above, I have found that I can separate one by one the metals mentioned above, all of which have been associated with crude bismuth which has come under my notice. In this, success though gradual, has been complete: but I was still confronted by the fact that the lead alloy was retained by the bismuth with a most charac- teristic persistency which seemed to defy all efforts of separation excepting by tedious wet or acid processes. The amount of lead existing in the bismuth I operated upon, after freeing it by dry processes from its other impurities, varied from 2 to 10 per cent. Bearing in mind the respective fusing points of lead and bismuth, it occurred to me that, as alloys of bismuth and lead fuse at a temperature considerably lower than that of bismuth itself, separation would possibly take place between the two metals at a certain point of cooling; I therefore made the following experiment :— Taking a quantity of bismuth (about 10 cwt.),- holding 11°5 per cent. of lead, and fusing same, I allowed the metal to cool until the major part of it had crystallised, then removing the fluid portion. The residue showed by assay only 6°35 per cent. of lead, pointing at once to the partial separation I had hoped for. These crystals again similarly treated showed only 3:75 per cent. of lead. The operation repeated gave crystals with only 2 per cent. of lead, and a fourth crystallisation brought this down to below 0°09 per cent. As a matter of possible interest, I subjoin the progressive results during the crystallising operations of several lots up to the point of bulking, and of finally separating every trace of lead :— Bismuth holding 146 per cent. Lead. Ist crystallisation gave crystals holding 9°8 per cent. of lead. 2nd 9 ” ” ol ” 9 3rd ” ” ” 38 ” ” Ath 2 2”? ” 2°09 My) ” 5th oP) ” 9 0-4 3 ”? Bismuth holding 12 per cent. Lead. Ist crystallisation gave crystals holding 6°2 per cent. of lead. 2nd 99 99 99 Ar2 99 99 ord. 33 i i» Heuiegaee 53 * Ath 9) 99 9 0-4 9 9 1887. | Contributions to the Metallurgy of Bismuth. 93 Bismuth holding 7°6 per cent. Lead. 1st crystallisation gave crystals holding 4:8 per cent. of lead. 2nd 39 99 9 3°8 ” ” 3rd 9 ” ” 0°8 ” ” Ath 9 ” ” 0°4 ” 9 Bismuth holding 11 per cent. Lead. Ist crystallisation gave crystals holding 5°5 per cent. of lead. 2nd ” oe) ” 2°5 ” ” 3rd 30 5° oe) 1:0 ” oe) Bismuth holding 5°6 per cent. Lead. Ist crystallisation gave crystals holding 2°0 per cent. of lead. 2nd ” ” ” 0-7 ” yy) 3rd Fe - under 0°5 - i Bismuth holding 5°3 per cent. Lead. 1st crystallisation gave crystals holding 1°8 per cent. of lead. 2nd 99 99 9) 0°6 19 99 ord i if under 0°5 : a Having attained this point, | worked upon several large quantities of metal—with practically the same results—finally succeeding by a continuation of the process in eliminating every trace of lead. By the above it will be seen that the process becomes an ex- ceedingly simple one, large quantities being treated at one time, involving littie or no loss, and occupying hours, instead of possibly weeks. To illustrate the facilities of the separation of lead and bismuth alloys, I give the following figures from metal holding originally five per cent. of lead. 10,675 lbs. produced, in the course of six to seven crystallisations, 9306 lbs. of available bismuth, the residue 1188 lbs. holding 40 per cent. of lead, so that from a quantity of nearly 5 tons of bismuth and lead alloy only about half a ton remained, holding practically the whole of the lead; the bulk of the bismuth separated by simple crys- tallisation holding traces only of lead, which, if necessary, could be readily eliminated by further crystallisation. From these facts it is apparent that the separation of these two metals can be effected by turning to account their relative fusing pownts. 94 Mr. E. B. Poulton. Ona special Colour-Relation [Feb. 10, Recapitulation of foregoing Experiment. 10,675 Ibs. leady bismuth, holding five per cent. lead, yielded 9306 lbs. of good commercial bismuth by the crystallization process, or within six per cent. of the total contents of pure bismuth. Leaving for subsequent treatment— Of alloy, holding 40 per cent. of lead, 1188 lbs., which is equal to 11°13 per cent. of the whole weight of metal treated. Average Analysis of the Bismuth Ores worked upon. Hasmibliine e/a ee eke ck ee eee 4.4c57 Pe ee ETA ea ae lar ce aca kT nes ee ene aoe PO MGTIMIOUY: 0a gal. cons ack roe eee 0°64 Arsenic”. Aa eae ae a Oh ee 1:26 Moly toden wim 2s shane bh. ae tute. cake i eee 0°02 Pellarinm 36). 20s ht eee ee 0:17 TPO es eget ee ue ee Oh ee ee 5°25 INMEBMIBATICSE 1 OU) oes eyalate ic biatkhe e See C ee 0°05 COMPeR inact si Was ek vals ala atace chats, ene eee ee 0-24 PUMESOIG ACI tak ae atgucte ee 31s es he eee 2°45 Adtemingde: hoi © ob ten O ee RR es oy ane ae ea 0:18 Magnesia ic. ko, ae ee ett. cs cae 0:09 Pomme ks EE EI Ee me 2 Oe 0°81 Carbonic: acids oe 3s; Sa eee 1:47 Satlplvar: ee. a Ve ec ene eee Cece ue me O77 Insoluble earthy matter, chiefly silica.......... 23°12 Water 2 ee Se Se eee tery ah eere aon Oxygen in combination and loss...-.........-. o19 100°00 IL. “ An Inquiry into the Cause and Extent of a special Colour- Relation between certain exposed Lepidopterous Pupe and the Surfaces which immediately surround them.” By EpWARD B. PoutTon, M.A., of Jesus and Keble Colleges, Oxford, Lecturer in Zoology and Comparative Anatomy at St. Mary’s Hospital, Paddington. Communicated by Professor E. RAy LANKESTER, F.R.S. Received Feb- ruary 10, 1887. (Abstract. ) Historical—_Mr. T. W. Wood first called attention to the colour- relation in pupz (‘Entom. Soc. Proc.,’ 1867, p. xcix), adducing 1887.] between certain Pupee and their Surroundings. 95 instances of Pieris brassice, P. rape, Vanessa polychloros, aud (erroneously) Papilio machaon. He even suggested that gilded surfaces might probably be found to produce gilded pup, but the experiment has never been made until the present investigation. His observations were disputed by many entomologists, but were confirmed by Mr. A. G. Butler and Professor Meldola (‘ Zool. Soc. Proc.,’ 1873). Finally, Mrs. Barber (‘ Entom. Soc. Trans.,’ 1874, p. 519) obtained striking results with the pupex of Papilio nireus (South Africa) which were confirmed by Mr. Roland Trimen, who experimented upon Papilio demoleus. Still later Fritz Miller (‘ Kosmos,’ vol. 12, p. 448) argues that the dimorphic pupe of Papilio polydamus do not possess the colour-relation. It was generally assumed that all the above instances of the colour-relation were to be explained by supposing the skin of the freshly formed pupa to be “ photographically sensitive,” but the explanation was never tested by any system of transference to other colours, and Professor Meldola pointed out in 1874 that there was no real analogy with photography. Furthermore, the explanation failed to account for the colour of pupz which threw off the larval skin on a dark night. I therefore thought that the problem would probably prove to be essentially physiological, and that the reflected light would be found to act on the larva at some time before pupation and not upon the pupa itself, and it seemed probable that the sensitive area might be defined by experiment. The investigation was conducted in the summer and autumn of 1886. I. Experiments upon Vanessa Io.—Material was kindly supplied by Mr. H. D. Y. Pode, of Slade, Ivybridge. Six mature larve were . placed in a glass cylinder surrounded by yellowish-green tissue-paper, and all suspended themselves from the paper roof. Five changed into the rarer yellowish-green form of pupa, and the sixth immediately after the skin had been thrown off and while still moist and with the shape unformed, was transferred to a black surface in darkness, but the pupal colours deepened into a yellowish-green tint exactly like that of the other five pupe. This experiment, so far as it went, confirmed my anticipation of larval as opposed to pupal susceptibility, and added another striking instance of pupal colour-relation. Mr. W. H. Harwood, of Colchester, also informed me that he had found the same variety of this species on the under side of nettle leaves, but not the dark form which occurs commonly on walls, stones, &c. Hence the protective value of the colour-relation is well seen; the species having varieties suitable for vegetal and mineral surroundings, and adjustable by the stimulus supplied by the colours of the environment. Il. Experiments upon Vanessa urticee.— This species was investigated in great detail, over 700 individuals being employed in the experi- ments. Material was in part supplied by Mr. Pode, but chiefly VOL. XLII. : H 96 Mr. E. B. Poulton. On a special Colour-Relation [Feb. 10, found near Oxford. The first necessity was the construction of a standard list of colours with which to compare the pups which had been the subjects of experiment. The pupz are very variable, and in many of the experiments the colour influence was only allowed to act during a small part of the time during which the larve are sensitive. — Hence the careful record of minute differences was absolutely necessary, and the standard list was made as detailed as possible. The list was as follows :— The degree of colour represented by— ' (1.) Very dark, from the large amount of cuticular pigment; no gilding or the merest trace. (2.) Dark normal form, but not so black as (1) and sometimes more gilding but very little. (3.) Light normal form, sometimes with a fair amount of gilding, often with a predominant pinkish tint. This degree was afterwards subdivided: into dark (38), (3), and light (8), and even further in certain experiments. (4.) Very light variety, often extremely golden; sometimes light pink. (5.) The lightest variety ; often completely covered with the gilded appearance. In the experiments summarised below, the individuals belonging to different companies were always separated, except in the larve subjected to green surroundings, so that the errors from varying hereditary tendencies were reduced to a minimum, for the larve of each company are hatched from the eggs laid by a single butterfly. 1. The Results of Different Colowrs— Orange surroundings produced no effect, as far as the experiment went, for the few pupe were all (3) and therefore showed no relation to the colour of the environment. After the experiment upon the allied V. Jo I tried the effects of green upon a large number of individuals, but the resulting pups were on | the whole rather darker than usual, probably because of the amount of shade produced by the tissue-paper. This conclusion suggested the use of black surroundings, and at once an immense effect was witnessed. These effects in turn suggested the use of white surroundings (white paper and white opal glass) and here also a powerful influence was exerted, the pups being often brilliantly golden in appearance. But it was clear that the very dark varieties were much better protected against the black surfaces than the lustrous golden pupz against the white surfaces, and this consideration suggested the use of a material with which the golden appearance harmonised most perfectly, 1.e., metallic gold. Boxes and cylinders lined with gilt paper and turned towards a strong light produced the most extremely gilded varieties in a large proportion of the pupx, and the metallic appearance was yellower and more truly golden than in the more silvery forms 1887. ] between certain Pupow and their Surroundings. oa produced by the use of white surroundings. The totals obtained by the use of these different surroundings were as follows (omitting the orange). Degrees of colour. (1.) | (2.) ® (3.) ee (4.) | (5.) Greeusurroundings ...,....| 2) 8] >. 2D isa. Loh ao Black i ee rog? | Vai! Maoh Ha Eo) OM tags White Br ord okies DP 7 oan Sze rAd elie: Wilt al ae Gilt i" Nine Tulle aes Ge" | oe lly ae ae 306 2. The Colours of Wild Pupe.—It is impossible to realise the extremely remarkable results of the gilt and white surroundings without taking into account the fact that a (4) or a (5) is very rarely seen in the field, except when the pupa is diseased. Out of fifteen wild pup found August 31 on a grey stone wall, the lightest pupzx were (3), while there were four of the degree represented by (1), and there was only the minutest spot of gold to be seen after careful exami- nation on two of the pups, and none on any of the others. 8. The Effects of Mutual Proximity.—Inasmuch as the above figures show that the larve are sensitive to dark surfaces and the larvee themselves are almost black, it appeared probable that they would be mutually influenced wheu a large number pupated in close proximity. This was incidentally shown to be the case in several of the experiments, of which the most striking was as follows. Four larvee were placed each in a separate cylinder while twelve were placed together in another similar cylinder, all having the same conditions of light and each cylinder lined and roofed with an equal amount of white paper and each standing upon an opal glass floor. Ofthe twelve larvee ten pupated in close proximity upon the roof and sides, and were all light (3), while the remaining two pupated on the floor and were both (4). Ofthe four pupe in separate cylinders two were (4) and two were (5). In consequence of these and other equally convincing results the exact position of the pups has to be taken into account in estimating the influences which have been at work, and inall the most careful experiments only one or two larve were placed in each coloured case. 4. The Hffects of Illwmimation.—One experiment was directed towards the comparison of the influence of a black surface in strong light and the same surface in darkness, and the results show clearly Hie 98 Mr. E. B. Poulton. Ona special Colour-Relation [¥Feb. 10, that the pups are on the whole darker in the latter circumstances, although dark under both conditions. In another experiment some larvee were suspended in a strong direct light without any coloured background sufficiently near to affect them, and as far as the experiment went it indicated that there was an influence in the direction of the lighter varieties, but in this case the numbers employed were too small to be convincing. 5. The Time during which the Larve are Sensitive-—The whole period preparatory to pupation, intervening between the cessation of feeding and pupation itself, may be divided into three stages: (i) in which the larva descends from the food-plant and wanders about in search of some (generally mineral) surface upon which to pupate; (ii) in which it rests motionless, usually in a curved position, upon the surface selected; (i11) in which it hangs head downwards sus- pended by its posterior claspers from a boss of silk spun at the close of the last stage. The duration of Stage (i) depends upon the varying proximity of suitable surfaces, and it was always greatly curtailed in confinement, because such surfaces were close at hand. If the larva is sensitive during this stage, the influences cannot generally contribute towards the result, because the larva is wandering over surfaces of various colours. It is also very improbable that the larva can be sensitive after the first few hours, or at any rate the first * half of Stage (iii), because rapid changes are taking place under the larval skin, and it is even likely that processes are already on their way towards completion which will result in the formation of pig- ment or other substances, which will many hours later deepen into the effective causes of pupal colour. The length of Stage (iii) did not vary very much in different larve, and in the shortest case observed the length was about 14 hours, while 20 hours was an unusually long period, but the majority of larve passed about 17 or 18 hours in this stage. Stage (11) was more variable, but about 15 hours was a common length, while 36 hours is a fair estimate of the length of the whole preparatory period. In the majority of cases a larva is probably sensitive to the colour of surrounding surfaces for about 20 hours preceding the last 12 hours of the whole preparatory period. Thus the length is amply sufficient to include many hours of daylight during which the surrounding surfaces are illuminated. If a larva be dis- turbed when Stage (11) is far advanced the whole period begins again, and all the three stages are again passed through, but they are all abbreviated, including Stage (i11), which had not previously com- menced. Many experiments indicated that darkness may increase the length of the stages; but my observations were not speciaily directed towards the settlement of this question, which only occurred to me when the notes were tabulated. Therefore I propose to specially investigate this point in the next season. Such prolongation, 1887. ] between certain Pupe and their Surroundings. 99 if corroborated, may be physiologically connected with pigment formation, or it may merely give the larva an additional opportunity of being acted on by light, if for any cause the illumination of the surrounding surface is delayed, or if the most sensitive part of the whole period corresponds to the ordinary darkness of night. 6. Hxperiments which show the Sensitive Condition during Stages (ii) and (1i1).—It was very important to obtain beyond any doubt the demonstration that the larve are sensitive during Stage (11), and also to decide conclusively whether any susceptibility was continued into Stage (iii), and if so to compare the relative susceptibilities of the two stages. Such experiments, if successful, would at once dispose of the older theory of pupal sensitiveness, and would be most important in making possible other methods of investigation which, applied to Stage (iii) alone, might successfully terminate the long and difficult search for the larval sensory surface which is affected by surrounding colours. A great many experiments were conducted with this object. The larvee were made to pass Stages (i) and (ii) exposed to the influence of a powerfully acting colour, and then were transferred for Stage (iii) to the colour which tended most strongly in the opposite direction. The largest, most carefully conducted, and most successful experiment of the kind gave the following results, all the larve belonging to the same company :— Dark Degrees of colour. — (ry (22) (3.) (3.) ae (4:.) | (5.) In black surroundings for the whole period . F si sa ee I Se, Da og eo! Transferred from black into gold for Stage (iii). . Bd |ane oe 1 5 3/..]/=9 Transferred from gold into black for Stage (ili) . : 6 9 =15 In gold surroundings for the whole period ............ 5 7| 8| =20 51 The analysis speaks for itself. Stages (ii) and (iii) are both sensitive, but Stage (iii) is much less sensitive than the other. Thus, when the earlier part of the period was passed in gilt surroundings, the resem- blance between the results and those produced by gilt surroundings acting during the whole period was much stronger than the resem- blance between the latter and the results produced when the gilt acted during Stage (iii) only. It is observable that the larve as a whole evidently tended towards the lighter forms, so that the black 100 Mr. E.B. Poulton. On a special Colour-Relation [Feb. 10, did not produce nearly such strong effects as the gilt surroundings. It is almost unnecessary to point how completely the old theory of pupal sensitiveness is broken down by the analysis. The experiment ‘shows that the more elaborate methods alluded to above could be appled to Stage (111) with at any rate a fair prospect of success. 7. The Search for the Sensitive Larval Surface. (a.) The Ocelli.— The most obvious suggestion pointed towards the larval ocelli (six in number on each side of the head) as the possible sense-organs which were acted on by surrounding colours, and formed the beginning of the physiological chain of which the end is seen in the colours of the pupa. In many different experiments the larvee were divided into two sets, with precisely similar conditions of surrounding colours and illumination, the one set of larve being normal while the ocelli of the other larve were carefully covered with an opaque black varnish, which was renewed more than once if necessary (the larve hemg very much irritated by the process and flinging their heads about so as to remove some of the varnish). The material made use of was a quickly-drying, photographic varnish, rendered opaque by the addition of lamp-black. Experiments of this kind were conducted with green, white, and gilt surroundings, but the pupez which were formed from the blinded larve could never be distinguished as a whole from the others, having been equally acted upon by surrounding colours. Even supposing the conditions of experiment had not been quite perfect, so that the ocelli were not wholly eliminated, we should expect some differences between the resulting pupe, if these organs represent the efficient sensory surface. After repeated experiments with negative results, I subjected two sets of larvee to the influence of black surroundings im darkness, thinking it possible (but highly improbable) that the process of blinding, or the varnish itself, might act as a stimulus to the ocelli, and so produce the light-coloured pupe. Again it was possible that the blinding might assist the influence of black surroundings, although it could not prevent the action of bright colours. Of, the resulting pupz, the set produced from the blinded larvz were rather lighter than the others, but there was little difference, and hence both suggestions were negatived, for the process obviously did not assist the influence of the surroundings, and the difference between the two sets was so slight as to offer no explanation of the brilliant pupa produced from blinded larvee by gilt or white surroundings, on the hypothesis that the process of blinding itself supplies a stimulus. (B.) Lhe Complex Branching Spines.—It seemed possible that these spines, of which there are seven on most of the segments, might contain some terminal organ which receives impression from coloured surfaces. When the spines are snipped off the bases bleed a little, so it is clear that a. subcuticular core is contained within them. The 1887.] between certain Pupe and their Surroundings. 101 bristles were shorn from several mature larve, and they were placed under exactly the same conditions of light and surroundings (white or gilt being used in three different experiments) as about an equal number of normal larve, but the pup of the two sets were almost exactly similar. (y.) The whole Shin Surface as Tested by Conflicting Colour Experi- ments.—It has been shown in paragraph 6 that the larve are to some extent sensitive during Stage (111), and I had long thought that this stage in which the larve are suspended motionless, and cannot be greatly affected by disturbance, might be investigated by the appli- cation of strongly conflicting colours to different parts of the larval surface. Black and gilt were obviously shown to be the best colours to select for the purpose, and the experiments were conducted in two ways. In the first the larve were induced to suspend themselves from sheets of clear glass, by placing them in wide shallow glass boxes, so that the ascent to the glass roof was easily accomplished. As soon as suspension had taken place each of the larvee was covered with a compartmented cardboard tube, of which the septum was perforated by a hole just large enough to admit the larval body. The tube was fixed to the glass sheet with glue, and the upper chamber and upper surface of the septum were lined with one colour, e.g., gold, while the lower chamber and lower surface of the septum were lined with the opposite colour, e.g., black, which also covered the outside of the cylinder, in case the larva should stretch beyond its lower edge. The septum was placed at such a height in the tube that the larval head and rather less than half of the total skin surface (anterior) were contained in the lower. chamber, while rather more than half of the skin surface (posterior) was con- tained in the upper chamber. It was thought thatthe upper chamber would be illuminated too strongly as compared with the lower, because its opening was directed upwards towards the light descending from the window, and therefore compensation was provided by fixing another perforated septum on the upper end of the cylinder, so that its Opening was reduced to the same diameter as the perforation in the septum between the two chambers. The results show that I overcompensated for the difference in illumination, for I did not take into account the fact that the larva spins its boss on a comparatively wide layer of silk which it has previously spun over the glass, and which greatly diminishes the transparency of the latter over an area at least equal to the diameter of the tube, which is comparatively thick, and includes the boss itself over the smaller area, corresponding to the perforation in the disk. Hence the resulting pups were rather lighter when the gilt chamber was below, although the difference was not great. At the close of the experiment I altered the conditions of illumination by removing the upper septum, and then the single pupa 102 Mr. E. B. Poulton. On a special Colour-Relation [Feb. 10, produced in a tube with the gilt chamber above proved to be the only (5) obtained in the whole of this set of experiments, in which 83 pupee had been compared. Such results show that the sensitive surface is not represented by a sense-organ in the head, or with an anterior portion only, but that the whole skin area possesses suscepti- bility. The second method of conducting conflicting colour experiments was superior in the more equal illumination of the gilt surface when above or below. Flat wooden trays were covered in each case with black and gilt paper in alternating areas, the two colours meeting along lines which ran across each tray, and along which shelves were fixed covered with gilt paper towards the gilt surface, and black paper towards the black surface. The shelves were perforated close toe the tray bottom with holes separated by equal distances, and of such a size as to easily admit the body of a larva with its spines, while the latter as in the compartmented tubes tend to cbhscure the interval between the larval body and the edge of the aperture. The trays were placed vertically in a strong east light, so that the shelves pro- jected horizontally, the black surface being uppermost in some cases, the gilt surface in others. Suspended larve were pinned (by the boss of silk) on to the uppermost colour in such a position over the holes that the head and first five segments of each larva passed through a hole into the colour beneath, which tended to produce oppo- site results. The curvature of the larval body brought the head close up to the underside of the shelf, and thus there was no chance of its being influenced by the colour above the shelf. Other larvee were similarly fixed between the shelves upon one colour only, so as to afford a comparison with the results of the conflicting colours. The pups obtained were on the whole rather lighter when the gilt surface was above, and hence the gilt surroundings influenced the rather larger posterior part of the skin to a greater extent than in the converse arrangement, when the effective colour was below. Hence on the whole the influence of conflicting colours has ended in as complete a confirmation of the numerous blinding experiments as the necessarily limited conditions of experiment could be expected to produce. 8. The Nature of the Effects Produced.i—The gilded appearance is one of the most metal-like appearances in any non-metallic substance. The optical explanation has never been understood. It has, however, been long known that it depends upon the cuticle, and needs the presence of moisture, and that it can be renewed, when the dry cuticle is moistened. Hence it can be preserved for any time in spirit. If a piece of dry cuticle be moistened on its upper surface the colour is not renewed, but almost instantly follows the application of spirit to the lower surface. Sections of the cuticle resemble those of Papilio machaon described in a previous paper (‘ Roy. Soc. Proc.,’ 1887. | between certain Pupe and their Surroundings. 103 vol. 38, 1885, p. 279), and show an upper thin layer, and a lower much thicker, finely laminated layer, which is also striated vertically to the surface. With Professor Ciifton’s kind assistance I have been able to show that the appearances follow from interference of light, due to the presence of films of liquid between the lamellee of the lower layer. The microscope shows brilliant red and green tints by reflected light, while in transmitted light the complementary colours are distinct, but without brilliancy. The latter colours are seen to change when pressure is applied to the surface of the cuticle, and when the process of drying is watched under the microscope, owing in both cases to the liquid films becoming thinner. In the dry cuticle the solid lamelle probably come into contact, and prevent the admission of air, which, if present, would cause even greater brilliancy than liquid. The spectroscope shows broad interference bands in the transmitted light, which change their position on altering the angle of incidence of the light which passes through the cuticle. Precisely similar colours, metallic on reflection, non-metallic and with the complementary tints on transmission, with the same spectroscopic appearances and changes induced by the same means, are seen in the surface films which are formed on bottle glass after prolonged exposure to earth and moisture. In the alternating layers of the pupa the chitinous lamelle are of higher, the liquid films of lower refractive index, hence water or alcohol pro- duce brilliant appearances, while liquids of higher refractive indices produce less effect. It is very interesting to note that this most specialised means of producing colour is probably derived in the most simple manner from the ordinary lamellated layer of other non-metallic pupe (e.g., P. machaon) in which the lamelle merely act as reflectors, so that the pupa is brightly coloured by absorption due to pigment contained in the outer lamelle only, and hence traversed twice by a large part of the incident light. The dark pupe of V. urticw, and the dark parts of the brilliant pups, contain abundant pigment in the upper thinner layer only, which therefore acts as a screen, and shuts off light from the lamel- lated layer below, thus preventing the metallic appearance. In the brilliant pupe this layer is transparent, and of a bright yellow colour, and doubtless assists im producing the yellowness of the golden appearance by absorption of light. The two layers are of different chemical constitution, for the upper will not stain in logwood, while the lower does so without difficulty. 9. The Biological Value of the Gilded Appearance.—Mr. T. W. Wood suggested that the appearance was so essentially unlike anything usually found in the organic kingdoms as to protect the organisms possessing it. Others have thought that it has the value of a warning colour, indicating an unpleasant taste. Itis probable that it is: now 104 Mr.E.B. Poulton. Ona special Colour-Relation [Feb. 10, used for this purpose, but it is improbable that such was its original meaning, for the fact that the appearance can be called up by the appropriate surroundings shows that it belongs to the highest class of protective colours, as far removed as possible from conspicuous warning colours, the object of which is to become as unlike their surroundings as possible. The former suggestion no doubt contains the true origin of the character, if we add to it the statement that the appearance is not only unlike anything organic, but strongly resem- bles many common mineral substances, especially the widespread mineral mica. ‘The darker pupz, on the other hand, resemble grey and weathered rock surfaces, just as the brilliant varieties resemble many exposed and recently fractured rocks. The shape of the Vanessa pupa is eminently angular and mineral looking. It is probable that the glittering form arose in a hot dry country, where exposed rocks would not weather for a long period of time. Gilded pupe of Vanessa are formed from larve which contain parasitic larvee of ichneumon flies, probably on account of the absence of pigment in such diseased individuals, and such absence being correlated with the gilded appearance, the latter is therefore formed. Vanessa Io has a green variety of pupa which appears when the insect is attached to its food-plant; V. atalanta has not such a form, and spins a tent of leaves when it pupates on the plant, while V. wrticee has neither the green variety nor the latter habit, and exhibits a strong disinclination to pupate among vegetal surroundings. During the past summer I only end three pupze of the species on the food-plant in the field, and all were ‘“‘ichnewmoned”’ and were abnormally gilded. III. Heperiments upon Vanessa atalanta—A few larve of this species, kindly sent me by Mr. J. L. Surrage, were subjected to gilt and to black surroundings, while a few others were left in bright light among the leaves oF the food-plant. The results hoon very completely with those obtained from V. urtice, the first set of pupe being uniformly golden, tlhe second very dark and with hardly any or none of the gilded appearance, while the third were intermediate bat nearer to the former. The length of Stage (ii) appeared to be about the same as in V. urtice, as far as this could be ascertained from the limited data. IV. Experiments upon Papilio machaon—Mr. W. H. Harwood supplied me with larve of this species. The eight largest were selected and placed in brown surroundings (twigs, &c.), four of them being blinded. The larve were very quiet and did not appear to be irritated by the process, which was repeated three times. The posi- tion of the ocelli on a distinct black area rendered it easy to ensure that they are all covered with varnish. Hight bright green pups were obtained, fixed to the brown stems or roof or lying free on the brown floor.. This result surprised me very much, for I knew that there 188 7.] between certain Pupe and ther Surroundings. 105 was a brown variety of the pupa not uncommon in this species. The remaining three larye were placed in green surroundings, one of them being blinded as above, but only one of the normal larve pupated, fixed to the green food-plant, and produced a distinct brown variety. These startling results show that there can be no suscepti- bility in this species, and this is all the more remarkable because the two varieties are so well marked, and because of the striking results obtained by Mrs. Barber and other observers on two species of South African Papilios. Fritz Miller, however, shows that another species of this genus resembles P. machaon in being dimorphic and yet not susceptible. The contradictory results obtained in my experiments were either due to the secondary association of one variety of a dimorphic species with an unhealthy condition or even a stunted size, as the gilded Vanessa. pup result from “ichneumoned”’ larve, or to the shade caused by the green tissue-paper. The eight largest and healthiest larve produced the green pupx, while of the three smaller larve only one pupated and formed a brown pupe. Mr. Harwood informs me that he has always looked with suspicion on the brown pupe, believing that they have been bred from larvee which were captured when small, and which are reared in close-fitting tin boxes; and he believes that the wild pupz, and those obtained from larve which were found when almost mature, are green. On the whole I think it is probable that the pupal dimorphism in this species is the remnant of a former suceptibility to coloured surroundings. V. Huperiments upon Pieris brassice .and P. rape.—These two species are treated together because they were in nearly all cases kept under similar conditions and were often placed in the same cylinders. The (nearly mature) larvae were almost always obtained, and the experiments conducted, at Seaview (Isle of Wight). 1. Standards of Pupal Colowr.—Degrees of colour were constructed by the comparison of a large number of individuals in each species. In these standard lists the pups were arranged in both species according to the relative predominance of black pigment, both as patches and minute dots, the latter tending to produce a grey appear- ance and obscuring the ground colour. The lightest degrees were classified according to the tint of the ground colour which had become prominent in the comparative absence of the pigment. 2. Hifects of various Colours acting during the Preparatory Period. («.) Black.—Interesting results following the use of this black ground under various conditions of illumination (P. rape only), the effects being stronger in the direction of pigment formation when the amount of light was increased (the opposite effect having been witnessed in V. urtice). The pupex of both species were dark in the great majority of instances after exposure to black surroundings in the larval state during the preparatory period. 106 Mr. E.B. Poulton. Ona special Colour-Relation [Feb. 10, (8.) White.——In this case also the effects were stronger (as shown in the prevention of pigment formation) as the surface was more highly illuminated (P. rape only). (y.) Colours of the Spectrum.—All the colours were used except violet, and the effects upon pigment formation in the two species were so graduated in the successive colours that it was possible to approxi- mately represent the results by a graphic method, making the abscissee of the scale of wave-lengths of the visible spectrum, and each ordinate of a length which corresponded to the average amounts of pigment obtained from all the pups subjected to any one colour, each ordinate being made to diverge at its base, and to include the degrees on the scale of wave-lengths which were shown by the spectroscope to corre- spond to the rays reflected (or transmitted) by the colour in question. Joining the summits of all the ordinates, the lines obtained were strikingly similar in the two species. The effects may be summarised as follows :— Colours. P. brassice. : P. rape. Black (for com- | Largest amount Largest amount parison). of pigment. of pigment. Dark red. Almost the same. ( Marked effects Deep orange. Smallest amount Wea naar Smallestamount ; on tint of pigment. | ground colour of pigment. j of r aie , | ground especially in colgue | the case of Pale yellow. Rather more. | ONE Rather more. Green. Rather more. ) Intermediate between the two last. Pale bluish-green.| Much more, almost equal to | More than in yellow. black and red. Dark blue. ss oe oe °° Still greater amount, but not nearly equal to black. The colours which most retard the formation of pigment were shown by the spectroscope to contain certain rays in common, 1.e., those from W.L. 0°00057—W.L. 0:00059, or 0:00060. The whole of the experiments on these species seemed to show that, of the light incident on the larval surface, the direct white light produces no effect at all (until after it has been reflected). Further experiments must decide whether direct light can be equally efficient with re- flected light, when it contains the same spectroscopic components. The green tissue-paper was quite insufficient to prove this, for it must have been largely coloured by absorption from reflected as well as transmitted light. 1887. | between certain Pupe and their Surroundings. 107 3. The Length of the Preparatory Period.—The observations were not sufficient to determine the duration of the periods and of its stages with any great accuracy, but all the experiments render it certain that the length is much greater in both species than in V. urtice. There were also some indications, as in V. urtice, that darkness may cause the prolongation of the period. 4. Blinding Hxperiments—The larve of P. rape were alone made use of, and they are as well suited to this method of investigation as P. machaon. The sets of pups produced from normal and blinded larvee were very similar, and thus the results harmonise with those of all the blinding experiments in other species of larve. &. Transference Hupervments.—A. considerable number of the larve of P. rape were transferred for the whole or part of Stage (iii) to a surface of a colour different from and generally opposite to that which had previously influenced them, and the results entirely har- monised with those previously described in other species, showing that the larva is sensitive and not the pupa, and that the time of greatest susceptibility is before Stage (111), or only including the first part of it, but also rendering it probable that the larve can be infinenced to a small extent during this stage. ' 6. The Nature of the Effects wrought upon .the Pupe.—The varied pigment effects which follow the influence of different surrounding colours are attended by other more deeply seated changes of even greater physiological interest and importance. The black pigment patches and minute black dots are cuticular and super- ficial, while the green, pink, or other ground colours are subcuticular and deep-seated, and in the most brightly coloured pup they are mixed colours, due to the existence of different pigmentary (and probably chlorophylloid) bodies present in different elements and at different depths in the subcuticular tissues of the same pupa. In other pupee no trace of such colours can be seen. Hence we see in these most complex and varied effects of the stimulus provided by the reflected light, which deepen into their permanent pupal condition very many hours after the stimulus has ceased to act, the strongest evidence for the existence of a chain of physiological processes almost unparalleled in intricacy and difficulty, while a theory of comparatively simple and direct photochemical changes induced by the stimulus itself, without such a physiological circle, seems entirely inadequate as an explanation of the facts, a conclusion which is borne out by a comparison with the experiments upon other species described in this paper. VI. Huperiments upon Ephyra pendularia.—After the consideration of the many species of variable pupze of the Rhopalocera, it is of inte- rest to compare the results of the investigation of the equally exposed and variable pupee of certain species of a single genus of Heterocera, 108 The Colour of Pupe and their Surroundings. [Feb. 10, the genns Ephyra. I observed this genus in 1883 (i.e., H. pendularia, FH. omicronaria, and E. orbicularia), and the results are published in ‘Entom. Soc. Trans.,’ 1884, pp. 50—56. The most curious result of the observation was the establishment of the fact that the green and brown larve always produce pupe of the same colour. [I think it is very probable (from the consideration of other partially published observations), although entirely untested in this genus, that the colours of the larve, and through them of the pups, could be con- trolled by the selection of appropriate surroundings during the whole or a large part of the larval stage. Concerning the different species made use of, EH. orbicularia is variable, E. pendularia regularly dimorphic green and brown, and ££. omicronaria dimorphic, with the brown forms very rare. The relative numbers of the green and brown larvee and pupee of 4. pendularia vary at different times of the year, the green forms greatly predominating in the summer brood, while they are not so abundant in the winter brood. When the parents of any set of larvee were both of the same colour in the larval stage there was a much larger proportion of that same colour in the resulting offspring. JI made some observations upon the situa- tions selected for pupation, thinking that these might show some relation to the pupal colours, but the results were not convincing, and were certainly highly irregular, but the experiment was not carried out in the best way, for there was not a sufficient quantity of both colours in thesurroundings. Dr. Wilhelm Miller, of Greifswald (Spengel, ‘Zool. Jahrb.,’ vol. 1, 1886, p. 234), calls attention to this remarkable and constant relation of larval to pupal colours, and expresses the belief that it is entirely exceptional, a statement which is of importance, when it is remembered that Dr. Miiller has worked carefully for many years on the South American larve. Hence certain species of Ephyridz afford an interesting contrast with all the other species of exposed pupze which have been hitherto observed. VII. Experiments upon the Colours of the Cocoon im Saturnia carpim.—At the suggestion of Mr. W. H. Harwood I made some experiments upon this species, and found that four cocoons which were spun in the corners of black calico bags were very dark brown in colour, while those of other larve which had been freely exposed to light until after they had begun to spin, and which were not sur- rounded by dark surfaces, were nearly all perfectly white, and when darker of a much paler tint, and very different from the four men- tioned above. Thus Mr. Harwood’s suggestion seems to be entirely confirmed, and another instance of the influence of surroundings is added, and one which it appears cannot be explained in any way except by the supposition of the existence of a complicated physio- logical, and apparently a nervous circuit. ooh.) | Presents, : 109 | Presents, February 10, 1887. Transactions. | ! Alnwick :—Berwickshire Naturalists’ Club. Proceedings. Vol, XI. Nos. 1-2. 8vo. [ Alnwick 1836]. The Club. Bombay :—Natural History Society. Vol. I. No.1. 8vo, Bombay 1886. The Society. London: — British Pharmaceutical Conference. Year-Book of Pharmacy. 1886. 8vo. London. The Conference. Institution of Mechanical Engineers. Proceedings. 1886. No. 4. 8vo. London. The Institution. Royal Institute of British Architects. Journal of Proceed- ings. Vol. III. Nos. 5-7. 4to. London 1887. The Institute, Royal Medical and Chirurgical Society. Proceedings. 1886. No. 14. 8vo. London. The Society. Royal United Service Institution, Journal. Vol. XXX. No. 137. 8vo. London 1886. - The Institution. Society of Biblical Archeology. Proceedings. Vol. I. Parts 1-2. Vol. JI.) Parts 1-2’ Vol. V.. Parts 1-2, Vols. VII-VIII- Svo. London 1872-1886. The Society. Society of Chemical Industry. Journal. 1886. No. 12. 8vo. London. The Society. Manchester :—Geological Society. Transactions. Vol. XiX. Part 2. 8vo. Manchester 1886. The Society. Melbourne :—Geological Society of Australasia. Transactions. Vol. I. Part 1. 4to. Melbourne 1886; List of Members, 1886. Svo, The Society, Paris :—Société de Géographie. Bulletin. 18835. Trim. 1. 8vo. Paris 1883; Annuaire du Bureau des Longitudes. 1856, 1866, 1880-81. 4 vols. 12mo. Paris. The Society. Observations and Reports. Brussels :—Observatoire. Annuaire 1887. 12mo. Bru«elles 1886. Lhe Observatory. Calcutta :—Meteorological Office. Report on the Administration of the Meteorological Department of the Government of India in 1885-86. Folio. [Calcutta]. The Office. London :—Meteorological Office. Daily Weather Reports. January to June, 1886. 4to.; Hourly Readings, 1885. Part IV. Ato. London 1886 ; Meteorological Observations at Stations of the Second Order, 1882. 4to. London 1887. The Office. Paris :—Bureau Central Météorologique. Annales. Années 1883- 84, 4 Vols. 4to. Paris 1886. The Bureau, 110 ’ Presents. | [Feb. 10, Observations, &c. (continued). Service Hydrographique de la Marine. Instructions Nautiques. Nos. 687, 689-691. 8vo. Paris 1886; Annales Hydrogra- phiques. Série II. Sem. 2, 1886. 8vo. Paris 1886. With . sundry Maps and Charts. | The Service. Salford :—Museum, Libraries, and Parks Committee. Annual Report. 1885-86. 8vo. Salford. The Committee. Ziirich :—Schweizerische Meteorologische Central-Anstalt. Anna- len. 1885. 4to. Zirich [1886]. The Institution. Journals. Anthony’s Photographic Bulletin. Vol. XVII. Nos. 23-24. Vol. XVIII. Nos. 1-2. 8vo. New York 1886-87. The Editor. Medico-Legal (The) Journal. Vol. III. No. 3. Vol. IV. Nos. 2-3. 8vo. New York 1885-86. The Medico-Legal Society. Meteorologische Zeitschrift. Jahrg. IV. Heft 1. Small folio. Berlin 1887. Deutsche Meteorologische Gesellschaft. Morskoi Sbornik. 1886. Nos. 8-12. 8vo. St. Petersburg. Compass Observatory, Cronstadt. Naturalist (The). No. 139. 8vo. London 1887. The Editors. New York Medical Journal. Nos. 1-4. 8vo. New York 1887. The Editor. Bekker (Dr.) Ueber den Streit der historischen und der filoso- fischen Rechtsschule. 4to. Heidelberg 1886. The University, Heidelberg. Hinde(G. J.) On the genus Hindia, Duncan, and the name of its typical species. 8vo. [London] 1887. The Author. Lipschitz (R.) Transformation d’une Somme de Deux ou de Trois Carrés. 4to. Paris [1887]. The Author. Mensbrugghe (G. van der) Sur l’Instabilité de I’Equilibre de la Couche Superficielle d’un Liquide. 8vo. Bruwelles 1886. The Author. 1887.] Cerebral Cortex. Radiant Matter Spectroscopy. 111 February 17, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. «A Record of Experiments upon the Functions of the Cerebral Cortex.” By Victor Horsey, M.B., F.R.CS., F.R.S., Professor Superintendent of the Brown Institution, and EDWARD ALBERT SCHAFER, F’.R.S., Jodrell Professor of Physiology in University College, London. (From the Physiological Laboratory of University College.) Received February 5, 1887. (Abstract. ) The paper consists, as its title implies, of a record of experiments relating to the functions of the cerebral cortex, a subject upon which the authors have been engaged during three years. The experiments have been entirely made uponmonkeys. After describing the methods employed, the general results of excitation and of extirpation of various parts of the cerebral hemispheres on one or both sides are given, and the cases in which the method of ablation has been employed are then recorded in detail, the symptoms observed during life and the condition of the brain after death being systematically noted. Hach case is illustrated by one or more drawings, showing the exact condition of the brain post mortem. In some instances sections of the brain are also represented. The paper includes also a topographical plan of the excitable or motor region of the cortex cerebrt. ; IJ. “On Radiant Matter Spectroscopy :—Examination of the Residual Glow.” By WitLtamM Crookss, F.R.S., V.P.C.S. Received February 10, 1887. The duration of phosphorescence after cessation of the exciting cause is known to vary within wide limits of time, from several hours in the case of the phosphorescent sulphides to a minute fraction of a VOL. XLII. - 112 Mr. W. Crookes. [Pébi ay second with uranium glass and sulphate of quinine. In my examina- tions of the phosphorescent earths glowing under the excitement of the induction discharge in vacuo, I have found very great differences in the duration of the residual glow. Some earths continue to phos- phoresce for an hour or more after the current is turned off, while others cease to give out the light the moment the current stops. Having succeeded in splitting up yttria into several simpler forms of matter differing in basic power,* and always seeking for further evidence of the separate identity of these bodies, I noticed occasionally that the residual glow was of a somewhat different colour to that it exhibited while the current was passing, and also that the spectrum of this residual glow seemed to show, as far as the faint light enabled me to make out, that some of the lines were missing. This pointed to another difference between the yttrium components, and with a view to examine the question more closely I devised an instrument similar to Becquerel’s phosphoroscope, but acting electrically instead of by means of direct light. The instrument, shown in fig. 1, A and B, consists of an opaque disk, a b c, 20 inches in diameter, and pierced with twelve openings near the edge as shown. By means of a multiplying wheel, d, and Fi@. 1, A. CAAT * © Roy. Soc. Proc.,’ vol. 40, pp. 502509 (June 10, 1886). 1887. | On Radiant Matter Spectroscopy. 113 Fria. 1, B. band, e f, the disk can be set in rapid rotation. At each revolution a stationary object behind one of the apertures is alternately exposed and hidden twelve times. A commutator, g (shown enlarged at fig. 1, B), forms part of the axis of the disk. The commutator is formed of a hollow cylinder of brass round a solid wooden cylinder. The brass is cut into two halves by a saw cut running diagonally to and fro round it, so as to form on each half of the cylinder twelve deeply cut teeth interlocking, and insulated from these on the opposing half cylinder by an air space about 2 mm. across. Only one half hhh, of the cylinder is used, the other, 7 77, being idle; it might have been eut away altogether were it not for some little use that it is in saving the rubbing-spring, 7, from too great friction when passing rapidly over the serrated edge. To a block beneath the commutator are attached two springs, one, /, rubbing permanently against the con- tinuous base of the serrated hemicylinder, h h, and the other, j, rub- bing over the points of the teeth of hh. By connecting these springs with the wires from a battery it will be seen that rotation of the com- mutator produces alternate makes and breaks in the current. The spring, j, rubbing against the teeth is made with a little adjustment sideways, so that it can be said to touch the points of the teeth only, 12 114 Mr. W. Crookes. [Feb. 17, when the breaks will be much longer than the makes, or it can be set to rub near the base of the teeth, when the current will remain on for a much longer time and the intervals of no current will be very short. By means of a screw, //, attached to the spring, any desired ratio between the makes and the breaks can be obtained. The intermittent primary current is then carried to an induction coil, m, the secondary current from which passes through the vacuum tube, n, containing the earth under examination. Whenthe commutator, the coil-break, and the position of the vacuum tube are in proper adjustment, no light is seen when looked at from the front if the wheel is turned slowly (supposing a substance like yttria is being examined), as the current does not begin till the tube is obscured by an intercepting segment, and it ends before the earth comes into view. When, how- ever, the wheel is turned more quickly, the residual phosphorescence lasts long enough to bridge over the brief interval of time elapsing between the cessation of the spark and the entry of the earth into the field of view, and the yttria is seen to glow with a faint light, which becomes brighter as the speed of the wheel increases. To count the revolutions, a projecting stud, 0, is fastened to the rotating axis, and a piece of quill, p, is attached to the fixed support, so that at every revolution a click is produced. With a chronograph watch it is easy in this way to tell the time, to the tenth of a second, occupied in ten revolutions of the wheel. Under ordinary circumstances it is almost impossible to detect any phosphorescence in an earth until the vacuum is so high that the line spectrum of the residual gas begins to get faint ; otherwise the feeble glow of the phosphorescence is drowned by the greater brightness of the glowing gas. In this phosphoroscope, however, the light of glowing gas does not last an appreciable time, whilst that from the phosphorescent earth endures long enough for it to be caught in the instrument. By this means, therefore, I have been able to see the phosphorescence of yttria, for example, when the barometer gauge was 0 or 6 mm. below the barometer. When the earth under examination in the phosphoroscope is yttria free from samaria, and the residual emitted ight is examined in the spectroscope, not all the bands appear at the same speed of rotation. At a slow speed the double greenish-blue band of G@ (545) first comes into view, closely followed by the deep blue band of Ga (482). This is followed, on increasing the speed, by the bright citron band of Gé (574), and at the highest speed the red band of G¢ (619) is with difficulty seen. The following are measurements of the time of duration of the phosphorescences of the different constituents of yttrium. The wheel was first rotated slowly, until the first line visible in the spectroscope attached to the phosphoroscope appeared ; the speed was counted, 1887. ] On Radiant Matter Spectroscopy. 115 and it was then increased until the line next visible was seen. In this way the minimum speed of revolution necessary to bring each line into view was obtained, and from these data the duration of phosphorescence for each constituent of yttria was calculated. The time in the following table represents in decimals of a second the time elapsing between the cessation of the induction discharge and the visibility of the residual glow of the earth :— At 0°0035 sec. interval the green and blue lines of GS and Ga begin to be visible. At 0:0032 45 the citron line of Gd begins to be visible. At 0:00175 ee the deep red line of GZ (647) is just visible. At 0°00125 s the line of Go is almost as bright as that of Gf, and the , red line of G7 is visible. At 0°000875 ___s,, the highest speed the instrument could be revolved with accuracy, the whole of the lines usually seen in the yttria spectrum could be seen of nearly their usual brightness. I have already recorded* that phosphate of yttria, when phospho- vesced in vacuo, gives the green lines very strongly whilst the citron band is hazy and faint. The same tube of yttric phosphate was now examined in the phosphoroscope. The green lines of GB soon showed themselves on setting the wheel into rapid rotation, but I was unable to detect the citron band of Gé even at a very high speed. The effect of calcium on the phosphorescence of yttria and samaria has been frequently referred to in my previous papers. It may save time if I summarise the results here. About 1 per cent. of lime added to a badly phosphorescing body containing yttrium or samarium always causes it to phosphoresce well. It diminishes the sharpness of the citron line of Gé but increases in brightness. It also renders the deep blue line of Gz extremely bright. The green lines of GB are diminished in brightness. Lime also brings out the phospho- rescence of samarium, although by itself, or in the presence of a small quantity of yttrium, samarium scarcely phosphoresces at all. In the phosphoroscope the action of lime on yttrium is seen to entirely alter the order of visibility of the constituents of yttrium. In a mixture of equal parts yttrium and calcium, the citron Gé line is the first to be seen, then comes the Ga blue line, then the Gf green line, and finally the Gy red line. This may, I think, be explained somewhat as follows :—Calcium sulphate has a long residual phos- phorescence, whilst yttrium sulphate has a comparatively short residual phosphorescence. Now with yttrium, although the green phosphorescence of Gf lasts longest, it does not last nearly so long as that of calcium sulphate. The long residual vibrations of the calcium compound induce, in a mixture of calcium and yttrium, phospho- rescence in those yttric molecules (Gd) whose vibrations it can assist, * ‘Phil. Trans.,’ 1883, Part III (pp. 914—916). 116 Mr. W. Crookes. [Feb. 17, in advance of those (Gf) to which it is antagonistic; the line of Gé therefore appears earlier in the phosphoroscope than that of GA, although were calcium not present the line of G8 would appear first. Experiments were now tried with definite mixtures of yttria and lime as ignited sulphates, to see where the special influence of lime ou Gé ceased. : Yttrium. | Calcium. —_— | — = Per cent. | Per cent. De 25 Order of appearance in the phosphoroscope.—Gf, Ga, God, and Gyn. The citron line of Go is only to be seen at a high speed, and is then very faint. 95 5 Order of appearance in the phosphoroscope.—Ga, GB, and G6 (citron and blue) together, and lastly Gy (red). Ata very high speed the green lines of GB become far more luminous than any other line. 90 10 Order of appearance.—Go and Ga together, then G8, and lastly Gn. 80 20 Order of appearance.—G and Ga simultaneously, then GB, and lastly Gy. The residual phosphorescence last for 30 seconds after. the current stops. The light of this residual glow is entirely that of Gé. The line of GB comes into view at an interval of 0°0045 second. At 0°00175 second the line of Gy is just visible. BA B Order of appearance.—Go0 and Ga together, then Gf 40 60 and Gy together. 30 70 10 90 Order of appearance.—Go0, Ga, GB. 1 99 Order of appearance.—Gé, Ga. The green lines of GB could not be seen in the phosphoroscope ; they would probably be obliterated by the stronger green of the continuous spectrum given by the calcium. OU Ne) OU The action of barium on yttrium was now tried. The following mixtures (as ignited sulphates) were made :— Yttrium. | Barium. Per cent. | Per cent. (| In the phosphoroscope the Gf line appears earliest, but 95 Brey the blue Ga line is the next to be seen, whilst the red 90 10 line of Gn is the latest im appearing. As the per- 80 20 centage of yttrium increases the blue line more and (| more overtakes the red and increases in brightness. >, oye a Spectrum similar to the above. As the. percentage of yttrium increases the spectrum grows brighter. In He rie he phosph he earliest Ii is th 40 60 the phosphoroscope the earlest line to appear 1s the 30 70 GB green, then the Gy red, and next closely follow- 25 "5 J ing it the Ga blue. 1887.] — On Radiant Matter Spectroscopy. 117 Yttrium. | Barium. | a | Per cent. Per cent. (| In the radiant matter tube all these mixtures give similar spectra. The G§ green is a little brighter 20 80 | and the Gé citron is a little fainter than in the cor- 15 85... | responding mixtures of yttrium and calcium, but 10 90 : the whole of the yttrium lines are seen. In the 5 95 phosphoroscope the G8 green is the first to appear, | then the Gy red. The Go citron is not visible at any : speed. Red line of Gn is much brighter ; Gd is very faint, and the green of G8 is stronger. In the phosphoroscope the order of appearance is,—first the line of GB, then the red line of Gn. 99°5 | Phosphoresces with difficulty, of a light blue colour, but turns brick-red in the focus of the pole. Spectrum / . | very faint. Order of appearance to phosphoro- | scope :—G& first, the others too faint to be seen. 99 The next experiments were tried with strontium, to see what modi- fication the addition of this body to yttrium would produce. The following mixtures of ignited sulphates were experimented with :— | | Yttrium. | Strontium. Per cent. | Per cent. | 95 5 , A very good yttrium spectrum. In the phosphoroscope the order of appearance is—First the green of Gf, then the Ga blue, lastly the Gyn red. No Go citron | line could be seen. 80 20 | In the phosphoroscope the green of G8 is very promi- nent at a low speed, standing out sharply against a black background. With a higher velocity the Ga and G7 lines come into view. “| The ordinary spectrum of this and the neighbouring mixtures is very rich in the citron line of Gd, but 1 entirely fail to see a trace of this line in the phos- | phoroscope at any speed. The line of Gf is the first (| to come, then the blue line of Ga. 35 65 | At about this point a change comes over the appearance | in the phosphoroscope. The blue line of Ga is now the earliest to appear, and it is followed by the Gn red and GB green. No Go line is seen. a op) je) a C ee 25 75 | These mixtures are very similar to each other in the 15 85 _ phosphoroscope. The line of Ga comes first, next 5 95 | the Gy line, then G8 line. No Gé citron line has 0°5 99 °5 been seen in any of these mixtures. In a paper read before the Royal Society, June 18th, 1885*, I described the phosphorescence spectrum given by a mixture of * ‘Phil. Trans.,’ 1885, Part IT (p. 716). 118 Mr. W. Crookes. [Feb. 17, 61 parts of yttrium and 39 parts of samarium, and illustrated it by a coloured lithograph. Also in a paper read before the Royal Society, February 25th, 1886,* I described and figured the phosphorescent spectrum of an earth obtained in the fractionation of yttria which was identical, chemically and spectroscopically, with an earth dis- covered by M. de Marignac, and provisionally called by him Ya. I repeat here these spectra, with the spectrum of yttrium added for comparison. Omitting minor details, it is seen that the Ya spectrum Bi VOLT i Pl | | | a | yg "tg. 3. YK Gadolinia) a | Leg # Vitra 6l Samarin59. is identical with that of the mixture yttrium 61, samarium 39, with one important exception—the citron line of Gé in the former spec- trum is absent in the latter. Could I by any means remove Gé from the mixture of yttrium and samarium the residue would be Ya. I have little doubt that this will soon be accomplished, but in the meantime the phosphoroscope enables us to remove the line of Gé from the mixture. It is only necessary to add strontium to a suitable mixture of yttrium and samarium and view the phosphorescing mixture in the instrument when the wheel is rotating rapidly, to obtain a spectrum which is indistinguishable from that of Ya. In the search for bodies giving discontinuous phosphorescent spectra I have submitted a great number of earths and combinations * © Roy. Soc. Proc.,’ vol. 40, p. 236. 1387. | On Radiant Matter Spectroscopy. 119 to the electric discharge in vacuo, and have noted the results. As the superficial phosphorescence apart from the composition of the emitted light has formed the subject of several recent papers by my friend M. Lecoqg de Boisbaudran, before the Académie des Sciences, it may be useful if I place on record some of the more striking facts which have thus come under my notice. The bodies are arranged alphabetically, and, unless otherwise explained, were tested in the radiant matter tube in the form of ignited sulphates. Alumina, in any of the forms which give the crimson line (A6942 —6937) has a very persistent residual glow. In the phosphoroscope rubies shine with great brilliancy. This phosphorescence of alumina has recently been the subject of a paper read before the Royal Society.* ! Antimony oxide with 95 per cent. of lime (in the form of ignited sulphate). White phosphorescence,’ the spectrum showing a broad space in the yellow, cutting the red and orange off. In the phos- phoroscopes the residual glow is very strong, and of a greenish colour. The spectrum of the residual light shows that the red and orange are entirely obliterated, leaving the green and blue very luminous. Antimony oxide with 99 per cent. of lime gives a pale yellowish phos- phorescence, which on heating turns red. In other respects it is like the 5 per cent. mixture. Arsenious acid with 99 per cent. of lime gives a greenish-white phosphorescence like pure calcium sulphate. Barwum 5 per cent., calcium 95 per cent.—The sulphates phos- phoresce green, with specks of. yellow and violet. The spectrum is continuous, with slight concentration in the red, great concentration in the green, and in the orange a broad black band hazy at the edges. Bismuth 15 per cent., calcium 85 per cent., phosphoresces of a bright reddish-orange. The spectrum shows a tolerably sharp and broad dark band in the red and orange, and a strong concentration of light in the green and blue; the spectrum being continuous and divided into two parts by a black band in the yellow, as in the case of the antimony-calcium spectrum. In the phosphoroscope the red and orange disappear and the green and blue remain. Bismuth 7 per cent., calcium 93 per cent.—The action is similar to the 15 per cent. mixture, except the colour of the phosphorescence, which is whiter. In the phosphoroscope the red and orange below the dark band is cut off. With 2 per cent. of bismuth the same phenomena occur. With 0°5 bismuth the phosphorescence is greenish-blue and the spectrum is continuous, with strong concentrations in the orange and green. The phosphoroscope cuts off the red and orange. * “Roy. Soc. Proc.,’ vol. 42, 1887, p. 25. 120 Mr. W. Crookes. [Pebuas, Cadmiwm 1 per cent., calcium 99 per cent.—Similar to calcium sulphate, q. v. Calcium sulphate was prepared from a colourless and transparent: rhomb of Iceland spar which had been used for optical purposes. It was dissolved in nitric acid, the nitrate was decomposed with distilled sulphuric acid, and the ignited sulphate tested in the tube. The phosphorescence is bright greenish-blue without bands or lines. In the phosphoroscope the colour is arich green; the spectrum shows the red and orange entirely cut off, leaving the green and blue; the blue is especially strong. Calcium sulphates prepared from Professor Breithaupt’s calcites* were re-examined. All phosphoresce with the normal greenish-blue glow of calcium, except No. 11, which gives a reddish glow. A minute trace of samarium was found in this calcite, but not enough to affect the colour of the glow. In the phosphoroscope all the specimens give a continuous spectrum beyond the yellow, the red and orange being cut off as usual. Chromium 5 per cent., calcium 95 per cent., as sulphates, gives a. pale reddish phosphorescence. In the phosphoroscope the colour is. ereen, and the red and orange are cut off. 1 per cent. of chromium. with calcium phosphoresces green in the cold, and becomes a red when slightly heated. The behaviour of chromium with aluminium has already been described.t Copper sulphate with 95 per cent. calcium sulphate behaves like calcium sulphate. Diamonds phosphoresce of various colours. Those glowing pale blue have the longest residual glow, next come those phosphorescing- yellow; I am unable to detect any residual glow in diamonds phosphorescing of a reddish colour. A large diamond of a greenish hue, very phosphorescent, shines almost as brightly in the phosphoro- scope as out of it. Glucina phosphoresces of a rich blue colour. There appears to. be no residual glow with this earth in the phosphoroscope. Lanthanum.—All the specimens of lanthanum sulphate I have examined in the radiant-matter tube phosphoresce of a reddish colour, and give a broad hazy band in the orange, with a sharp line —1/d’280—superposed on it. This is identical with the line of Ge, one of the constituents of the samarium phosphorescent spectrum. Calcium added to lanthanum changes the colour of the phosphorescence from red to yellowish, and brings out yttrium and samarium lines, these metals being present as impurities; the Gé and Gz lines are also seen, but the space which should be occupied by the Gf green is now 2 dark space. I have shown that when Go, Ga, and GG are present, * < Phil, Urans.,, 1885) Part (a. 697). t ‘ Roy. Soc. Proc.,’ vol. 42, p. 28, et seq. 1887. | On Radiant Matter Spectroscopy. 121 in very small quantities with lime, the lines of Gé and Ga are intensified, while that of Gf is weakened. This new result seems to show that if only a small trace of G6 is present with lime and lanthanum, the green line is not only suppressed, but the quenching action has actually extended so far as to neutralise that part of the continuous lime spectrum having the same refrangibility as the Gf line, the result being a black space in the spectrum. In the phos- phoroscope the line of Ge is visible at the slowest speed; G6 comes in at an interval of 0°0035 second, and the Ga line immediately after- wards. Lead sulphate, by itself, in the radiant-matter tube glows with a nearly white colour, giving a continuous spectrum. In the phos- phoroscope the red and orange are cut off, leaving a strong concen- tration of light in the green and blue. 5 per cent. of lead added to _ calcium sulphate phosphoresces like lime. Magnesia phosphoresces pink. 5 per cent. with lime, as sulphates, give a greenish phosphorescence, with a tendency to turn red as the powder heats. As the Oriental ruby contains between 1 and 2 per cent. of magnesia, a mixture was prepared of acetate of alumina with 2 per cent. of magnesia, and tested after ignition. It gave no spectrum or lines. This was done to see if the crimson line of aluminium might be due to the presence of magnesia. Nickel added to calcium sulphate in the proportion of 5 per cent. makes no alteration in the usual phosphorescent phenomena of calcium. Potassium, 5 per cent., added to calcium sulphate gives a bright phosphorescence, and made the residual glow very persistent. Samarvum.—T he phosphorescent behaviour of this body, alone and mixed with other substances, has been fully described in my paper on samarium.* Scandium, either in the form of earth or sulphate, phosphoresces. of a very faint blue colour, but the light is too feeble to enable a spectrum to be seen. Addition of lime does not bring out any lines. Sodium sulphate mixed with an excess of calcium sulphate gives a, greenish tinge to the usual colour of the phosphorescence. The sodium line is visible in the spectrum. Strontia in the radiant-matter tube glows with a rich blue colour, showing in the spectroscope a continuous spectrum with a great: concentration of light in the blue and violet. In the phosphoroscope the colour of the glow is bright green, showing in the spectroscope a. continuous spectrum, with the red and blue ends cut off. A mixture of calcium sulphate with 5 per cent. of strontium sulphate behaves. like calcium sulphate alone. ~ * ‘Phil. Trans.,’ 1885, Part II (pp. 709—-721). 122 Mr, W. Crookes. [Feb. 17, Thorium, as oxide or sulphate, refuses to phosphoresce, and the tube rapidly becomes non-conducting. A tube with thoria at one end and a phosphorescent earth such as lime or yttria at the other end, and furnished with a pair of poles near each end, at a particular exhaustion is non-conducting at the thoria end, while it conducts at the yttria end. If the wires of the induction coil are attached to the poles at the thoria end, no current will pass; rather than pass through the tube, the spark prefers to strike across the spark gauge—a striking distance of 37 mm.—showing an electromotive force of 34,040 volts. Without doing anything to affect the degree of exhaustion, on trans- ferring the wires of the induction coil from the thoria to the yttria end, the spark passes at once. To balance the spark in air the wires of the gauge must be made to approach till they are only 7 mm. apart, equivalent to an electromotive force of 6440 volts; the fact of whether thoria or yttria is under the poles making a difference of | 27,600 volts in the conductivity of the tube. The explanation of this action of thoria is not yet quite clear. From the great difference in the phosphorescence of the two earths, it is evident that the passage of the electricity through these tubes is not so much dependent on the degree of exhaustion as upon the phosphorogenic property of the body opposite the poles. This view is supported by the fact that the thoria may be replaced by a metal wire, when the same obstructive action will result. : Lime does not give phosphorescent properties to thoria, if this earth be pure, but it brings out the lines of yttrium and samarium which are almost always present in small quantities in thoria unless it has been specially purified. Tin with 95 per cent. of lime gives the lime phosphorescence only. Thulium and erbium together phosphoresce with a green light, giving the erbium spectrum already described before this Society.* There is, in addition, a faint blue line apparently double (see ““Ytterbium”’). The addition of lime causes the mixture to phos- phoresce of a pale blue colour. The spectrum now shows a bright blue band, in the same position as the faint double blue band seen in the absence of lime. The blue line of Ga is also seen, and a faint line of Gé. The deep red line of Gy, one of the constituents of the ordinary yttria spectrum, is prominent in this spectrum. Tungsten and uranium, each mixed with 95 per cent. of lime, only give the lime spectrum. Yiterbium.—I have not yet succeeded in preparing this body of trustworthy purity; but through the kindness of Professor Cléve, M. de Marignac, and Professor Nilson I have been enabled to experiment with specimens of ytterbia prepared by these chemists. * ‘Roy. Soc. Proc.,’ vol. 40, p. 77, fig. 1 (January 7, 1886). 1887. | On Radiant Matter Spectroscopy. 123 Professor Cléve’s ytterbia, in the form of sulphate, gives in the radiant-matter tube a blue phosphorescence, the spectrem of which shows a strong double blue band,* together with traces of the Gé and the erbia green lines. The addition of lime broadens the blue band and makes it single. Professor Cléve writes that this ytterbia may contain some traces of thulia, perhaps also of erbia, but scarcely any other impurities. Measurements in the spectroscope give the follow- ing approximate results. Scale of A. ioe Remarks. spectroscope. r2 8°63 4626 4673 Commencement of first blue line. This edge is very hazy. 8°54 4574. 4780 Centre of the first blue line. 8°45 4524: 4885 End of first blue line. 8°44 4518 4898 Centre of dark interval between the two blue lines. 8°40 4475 4994. Centre of second blue line. This line is narrower than the first line. The following are measurements taken with the mixture of this ytterbia and lime :— Scale of FR. te Remarks. spectroscope. a 8°71 4674 4577 Up to this point there is the con- tinuous spectrum of li-calcium. Here a black space commences. 8°515 4555 4819 Commencement of a hazy blue band. 8 °475 4538 4855 End of hazy blue band. This band is of considerable brilliancy. These blue bands are seen much fainter without lime, and are about as strong in the mixture of thulia and erbia with lime described above. I had ascribed them to ytterbia, when Professor Nilson kindly forwarded me a small specimen of ytterbia, considered by him perfectly pure, and used for his atomic weight determinations. This ytterbia gives absolutely no blue bands. The origin of these bands therefore remains uncertain. * This is the band spoken of in my Royal Society paper of 9th June last (‘ Roy. Soc. Proc.,’ vol. 40, 1886, p. 507), provisionally called Sy, and ascribed to ytterbia. If it is not due to ytterbia it is evidence of a new body. 124 Mr. W. Crookes. — [Feb. 17, Ytterbia from Professor Nilson, in the form of sulphate, refuses to phosphoresce without the addition of lime. When lime is added it only brings out traces of the phosphorescent bands of Ge, GB, and Ga. Evidently these are impurities. Ytterbia from M. de Marignac is identical with that from M. Cléve, as far as my examination can go. In sending me this ytterbia M. de Marignac warned me that he was very far from thinking it pure. Yttriwm.—During the fractionation of the higher fractions of yttria (+6, 118 and 119), a very sharp green line sometimes makes its appearance, situated between GG and Gy (approximate position on the 1/\? seale, 325). It is very faint, and is not connected with the orange line of 86, although it is as sharp. The yttria showing these lines phosphoresces of a transparent golden-yellow colour, the fractions at the other end phosphorescing yellowish green. 7 I have previously described the action of a large number of bodies on the phosphorescence of samarium.* The experiments resulting in the following observations were tried at about the same time. I will describe them in alphabetical order. Unless otherwise mentioned all the mixtures were in the form of anhydrous sulphates. Yitriwm 5 per cent., aluminiwm 95 per cent., gives a good yttria spectrum ; the blue line of Ga is very distinct, and the double green of Gf is well divided. In the phosphoroscope the G® and Ga lines first appear simultaneously, then the Gé line. Yttrium 99°5 per cent., bismuth 0°5 per cent.—The spectrum is bright, and on close examination a trace of samarium green, Gy, is to be detected forming a wing to the Gé line. In the phosphoroscope the citron line of Gé entirely disappears and the samarium double green line, which out of the phosphoroscope is almost obscured by the great brightness of Gé, now appears distinctly, together with the green Gp line. Yttrium 95 per cent., bismuth 5 per cent., gives the usual yttria spectrum. No Gé line appears in the phosphoroscope at any speed. At first only the G3line is seen, and next the Ga line appears, asin yttria. On gradually increasing the percentage of bismuth the spectrum of yttria grows fainter, until with 95 per cent. of bismuth the phosphorescence is bad and the spectrum faint. Yttrium 5 per cent., cadmium 95 per cent., gives a brilliant phos- phorescence, but the spectrum is almost continuous. In the phos- phoroscope a faint concentration of light is seen in the green, which becomes sharper as the speed increases. The action of calcium on the phosphorescence of yttrium has already been described. Yttrium and certwm.—Cerium has the effect of deadening the * “On Radiant Matter Spectroscopy. Part 2—Samarium.” ‘ Phil. Trans.,’ 1885, Part IL (pp. 710—722). 1887. ] On Radiant Matter Spectroscopy. 125 brilliancy of the yttrium spectrum in proportion to the quantity added. All the bands remain of their normal sharpness. Yttrium 5 per cent., copper 95 per cent., phosphoresces very feebly. Yitrium 90 per cent., didymiwm 10 per cent.—This mixture gives a good yttria spectrum. Yttrium 70 per cent., didymium 30 per cent., phosphoresces very fairly and gives all the usual lines. Yttrium 50 per cent., didymium 50 per cent., refuses to phos- phoresce. The tube is either too full of gas to allow the phosphor- escence to be seen or it becomes non-conducting. When the mixture is illuminated by the glowing gas the absorption lines of didymium the green are seen. With higher proportions of didymium the same results are produced. On adding 25 per cent. of lime to the mixture containing 50 per cent. of didymium the yttria spectrum is brought out very well. Lime added to a mixture of 10 per cent. yttria and 90 per cent. didymium brings out the yttrium spectrum fairly, but the tube soon becomes non-conducting. Yttrium 5 per cent. and glucinwm 95 per cent. gives a bright phos- phorescence, but the definition of the spectrum lines of yttria is bad. Yitrium 5 per cent., thalliwm 95 per cent.—No spectrum is given by this mixture, it turns black and refuses to phosphoresce. Yttrvwm 5 per cent., tu 95 per cent., phosphoresces faintly, the lines being very indistinct. Yttrium 5 per cent., titaniwm 95 per cent., acts like thoria, and the tube becomes non-conducting. Yitrwum 5 per cent., twngsten 95 per cent.—This phosphoresces of a bright yellow colour, the spectrum is brilliant, but the lines are not sharply defined. In the phosphoroscope the colour becomes greenish, and the spectrum shows only the green lines of GG. Yitrium 5 per cent., zinc 95 per cent.—The phosphorescence is of a pale yellowish-white, and the spectrum is very brilliant, being equal to that shown by 30 per cent. of yttrium with barium, calcium, mag- nesium, or strontium. In the phosphoroscope the colour becomes reddish, and the Gf green line is the first to come. No citron line is seen. If the yttrium contains a trace of samarium, the samarium spectrum, which is scarcely seen under ordinary circumstances, now comes out distinctly. Zinc sulphate mixed with 95 per cent. of calcium sulphate phos- phoresces a bright bluish-green colour; the spectrum contains no bands or lines. Zinc sulphide (Sidot’s hexagonal blende*).—This is the most bril- liantly phosphorescent body I have yet met with. In the vacuum tube it begins to phosphoresce at an exhaustion of several inches below * “Comptes Rendus,’ vol. 62, 1886, pp. 999—1001 ; vol. 63, 1866, pp. 188 —182. 126 Mr. W. Crookes. [ Peboit, a vacuum. At first only a green glow can be seen; as the exhaustion gets better a little blue phosphorescence comes round the edges. At a high exhaustion, on passing the current the green and blue glows are about equal in brightness, but the blue glow vanishes imme- diately the current stops, while the green glow lasts for an hour or more. In the phosphoroscope the blue glow is only seen at a very high speed, but the green glow is seen at the slowest speed, and the body is almost as bright in the instrument as out of it. Some parts of a crystalline mass of blende which, under the action of radiant matter, leave a glow with a bright blue colour, leave a green residual light when the current ceases; other parts which glow blue become instantly dark on stopping the current. The different action of calcium, barium, and strontium on the con- stituents of yttrium is an additional proof, if confirmation be needed, that the bodies I have provisionally called Ga, GB, Gé, &c.,* are sepa- rate entities. It may be as well here to collect together the evidence on which I rely to support this view. I will take the bodies sertatum :—. Ga.—An earth phosphorescing with a blue light, and showing in the spectroscope a deep blue line, of a mean wave-length 482. This earth occurs in different proportions in purified yttria from different minerals. Samarskite, gadolinite, hielmite, monazite, xeno- time, euxenite, and arrhenite contain most Ga, whilst fluocerite and cerite contained notably less of this constituent. The addition of lime brings out the phosphorescence in Ga in advance of that of the other constituents. The behaviour in the phosphoroscope of Ga when mixed with the alkaline earths also points to a difference between it and its associates. With lime the blue phosphorescent band of Ge comes into view at a very low speed, the order of appearance with a small quantity of lime being Gf, Ga, Gé, and with a large quantity of lime, Gé, Ge, G8. Employing strontia instead of lime, the order of appearance in the phosphoroscope when the quantity of strontia is small is GB, Ga, Gy, and when the quantity of strontia is in excess, Ga, Gy, GB. Baryta in small quantity brings out the lines in the phosphoroscope in the following order: GS, Ga, Gy, but when the baryta is in excess the order is Gf, Gy, Ga. The chemical position taken up by Ge in the fractionation scheme precludes it from being due to the bodies I have called GB, Gy, Ge, GE, Sy, or Sd. It closely accompanies Gé (the earth giving the citron line), concentrating at the least basic end, and I have not yet succeeded in effecting a sepa- ration of the two. If, therefore, Ga is not a separate entity, its blue line must be due to the citron-band-forming body called Gé. The difference between Ga and Gé is brought out in a marked manner by * ‘ Roy. Soc. Proc.,’ vol. 40, 1886, p. 502. 1887. ] On Radiant Matter Spectroscopy. 127 the phosphoroscope when baryta or strontia is present; the citron line of Gé being entirely suppressed, while the blue line of Gz is brought out with enhanced brilliancy. For these reasons I am in- clined to regard Ga as a separate body, although the evidence in favour of this view is not so strong as in the case of some of its other associates. GB.—An earth phosphorescing with green light, and showing in the spectroscope a close pair of greenish-blue lines of a mean wave- length of 545. This earth can be separated by chemical fractionation from the other constituents of yttrium. It concentrates at the most basic end, and is present in the samarium which invariably makes its appearance at this end of the fractionation of yttrium. Itis one of the prominent lines in Ya, where also it accompanies some of the samarium lines. Gf, however, is not a constituent of samarium, for it is easy to purify samarium by chemical means so that it does not show a trace of the Gf green lines, although it is very difficult to get _ Gf free from some of the samarium lines. The residual phosphor- escence of Gf is very considerable, and its green lines show first in the phosphoroscope when only yttrium is present. The addition of lime keeps back the glow of G#, and brings forward that of Ge. Strontium and barium act on Gf very differently to lime. A small quantity of strontium brings forward the residual glow of Gf, whilst in large quantities strontium keeps the phosphorescence of GB back to the last. Gy.—An earth phosphorescing with a green colour, and showing in the spectroscope a green line having a wave-length of 564. This is one of the least definite of all the supposed new bodies. It appears to be a constituent of samarium, occurring in the fractionation of yttrium among the most basic constituents connecting yttrium and samarium. Its point of maximum intensity is, chemically, very well marked, and is at a different part of the fractionation scheme to those of the other lines of samarium, especially Ge. On dilution with lime the phosphorescent line of Gy vanishes before that of Ge. Gé.—An earth phosphorescing with a citron-coloured light, and showing in the spectroscope a citron line having a wave-length of 574. Gé is one of the least basic of all the bodies associated in yttrium, occurring almost at one extremity of the fractionation. It is not very difficult to separate chemically Gé from all the other accompany- ing bodies except the one which I have called Ge (giving the deep blue line). Not only can Gé be obtained free from the other four con- stituents of yttrium, but the body called by M. de Marignac Ya is a proof that the other four components of yttrium can be obtained quite free from Gé. Lime intensifies the phosphorescence of Gé, and deadens that of GB, while strontium has the opposite action. The behaviour of Gé in the phosphoroscope, when mixed with lime, VOL. XLII. K 128 Mr. W. Crookes. [Feb. 17, strontia, or baryta, also affords a striking evidence of individuality, lime enhancing the residual glow, while strontia and baryta altogether suppress it. Ge.—An earth phosphorescing with a yellow colour, and, in the spectroscope, showing a sharp yellow line having a wave-length of ©97. It is seen in the samarium spectrum as a sharp yellow line superposed on a hazy double band. As I have already pointed out, Ge fractionates out high up among the most basic earths, and gener- ally accompanies lanthanum. In the phosphorescent spectrum of lanthanum the line Ge is seen quite free from the lines of other bodies. G¢.—An earth phosphorescing with a red light, showing in the spectroscope a red line of wave-length 619. This body is always more plentiful in yttrium obtained from samarskite and cerite than from gadolinite, hielmite, and euxenite, and is almost absent in yttrium from xenotime. G¢ is. of about intermediate basicity. Working with -samarskite yttria, Gf becomes most brilliant after the line of Gy has completely disappeared. Further fractionation causes the line of G¢ to fade out, and the citron and blue lines are then left. The phosphorescence of G¢ is developed to a different extent according to the metal with which the yttria is mixed. The order (beginning with the substance having the greatest action) is zirco- nium, tin, aluminium, bismuth, glucinum. Gy.—An earth phosphorescing with a deep red light, and showing in the spectroscope a red line having a wave-length of 647. Like its fellow red constituent, Gy occurs most plentifully in samarskite yttrium, and scarcely at all in yttrium from hielmite, euxenite, and cerite. It is the first of the strictly yttrium constituents to separate out, on fractionation, at the most basic extremity, leaving Ga, GB, Gé, and Gg. In almost all samples of yttria, except when very highly purified, Gy is seen very brilliantly, and by its side can be detected the faint red band of samarium. In the phosphoroscope the line of Gy is the last to appear when yttria alone is being observed; strontia and baryta enhance the residual glow of Gy, strontia in moderate quantities bringing it out before that of Gf, while baryta brings it out. after GA. Sé.—An earth giving in the spectroscope when phosphorescing a very sharp orange line of wave-length 609. I have aiready* dis- cussed the claims of this earth to be considered a separate entity. It is not present in the rare earths from gadolinite, xenotime, monazite, hielmite, euxenite, and arrhenite; it is present in small quantity in cerite, and somewhat more plentifully in samarskite. In samarskite yttrium it conceutrates at a definite part of the fractionation. Its * * Roy. Soc. Froc.,’ vol, 40, 1886, p. 540. 1887.] On Radiant Matter Spectroscopy. 129 sharp orange line is not strong enough to be seen in the phosphoro- scope. A siitele calcium entirely suppresses the orange line, vale samarium or yttrium seems to intensify it. In addition to the above earths, it is not improbable that the sharp green line (1/\*325) mentioned under the heading “ Yttrium” may be caused by still another earth. The brilliant and characteristic spark spectra yielded when certain elements are volatilised and rendered incandescent by the spark from a powerful induction coil are relied on by chemists as an indisputable proof of the identity of such elements. Bearing this in mind I have endeavoured toascertain how these yttrium constituents would behave in respect to the spark spectrum. Do the definite system of lines in the old yttrium spark spectrum belong to one constituent only, or are the yttrium lines broken up and distributed among the different bodies I have designated as Ga, GB, &c.P Also do the other con- stituents possess special spark spectra of their own? Very careful and long-continued experiments have shown me that neither of these hypothetical cases occur. The spark spectrum given by old yttrium is shown in the drawing (fig. 5). It is chiefly characterised by two very strong groups of lines in the red and orange. I now take the earth Gd. This occurs near one end of the fractioning, and not only differs from the parent yttrium in its phosphorescent spectrum, but by virtue of the process adopted for its isolation it must likewise differ in its chemical pro- perties. On examining its spark spectrum I see absolutely no difference between this spectrum and the one given by old yttrium. I now pass to the other end of the fractionation of yttrium, where occurs a concentration of a body giving a totally different phospho- rescent spectrum to the one at the first end. And it also differs chemically from old yttrium, and in a more marked manner from its brother, G6, at the other extremity of the fractionation. Here again its spark spectrum is perfectly identical both with old yttrium and with Gé, and however closely I examine these three spectra in my laboratory, the whole system of lines is still identical. 2 Kk 130 On Radiant Matter Spectroscopy. [Feb. 17, Respecting the theoretical considerations involved in these results, I see two possible explanations of the facts brought forward. Ac- cording to one hypothesis, research has somewhat enlarged the field lying between the indications given by ordinary coarse chemistry and the searching scrutiny of the prism. Our notions of a chemical element have expanded. Hitherto the molecule has been regarded as an aggregate of two or more atoms, and no account has been taken of the architectural design on which these atoms have been joined. We may consider that the structure of a chemical element is more complicated than has hitherto been supposed. Between the molecules we are accustomed to deal with in chemical reactions and the ultimate atoms, come smaller molecules or aggregates of physical atoms; these sub-molecules differ one from the other, according to the position they occupied in the yttrium edifice. An alternative theory commends itself to chemists, to the effect | that the various bodies discussed above are new chemical elements differing from yttrium and samarium in basic powers and several other chemical and physical properties, but not sufficiently to enable us_ to effect any but a slight separation. One of these bodies, G6, gives the phosphorescent citron line, and also the brilliant electric spectrum. The other seven do not give electric spectra which can be recognised in the presence of a small quantity of Gé, whilst the electric spectrum of Gé is so sensitive that it shines out in undiminished brilliancy even when the quantity present is extremely minute. In the process of fractionation, Ga, GB, Ge, &e., are spread out and more or less separated from one another, yet the separation is imperfect at the best, and at any part there is enough Gé to reveal its presence by the sensitive electric spark test. The arguments in favour of each | theory are strong and pretty evenly balanced. The compound mole- cule explanation is a good working hypothesis, which I think may account for the facts, while it does not postulate the rather heroic alternative of calling into existence eight or nine new elements to explain the phenomena. However, I submit it only as an hypothesis. If further research shows the new element theory is more reasonable, I shall be the first person to accept it. Neither of these theories agrees with that of M. Lecog de Bois- baudran, who also has worked on these earths for some time. He considers that what I have called yttrium is a true element, giving a characteristic spark spectrum, but not giving a phosphorescent spectrum im vacuo. The bodies giving the phosphorescent spectra he considers to be impurities in yttrium. These he says are two in number, and he has provisionally named them Za and ZB. By a method of his own, differing from mine, M. de Boisbaudran obtains fluorescent spectra of these bodies; but their fluorescent bands are extremely hazy and faint, rendering identification difficult. Some 1887. ] Presents. 131 of them fall near lines in the spectra of my GG and Gé. At first sight it might appear that his and my spectra were due to the same bodies, but according to M. de Boisbaudran, the chemical pro- perties of the earths producing them are widely distinct. These giving phosphorescent lines by my method occur at the yttrium extremity of the fractionation, where his fluorescent bands are scarcely shown at all; whilst his fluorescent phenomena are at their maxi- mum quite at the terbium end of the fractionation, where no yttrium can be detected even by the direct spark, and where my phosphe- rescent lines are almost absent. Presents, February 17, 1887. Transactions. Bordeaux :—Société de Médecine et de Chirurgie. Mémoires et Bulletins. 1886. Fasc. 1-2. 8vo. Bordeaux. The Society. Brisbane :—Geographical Society of Australasia. Queensland Branch. Proceedings. Vol. I. Session 1885-86. 8vo. Brisbane 1886. The Society. Brussels :—Musée Royal d'Histoire Naturelle de Belgique. Bulletin. Tome IV. No. 4. Evo. Bruwelles 1886. The Museum. Erlangen :—Physikalisch-Medizinische Societit. Sitzungsberichte. Heft 18. 8vo. Hrlangen 1886. The Society. Kingston, Canada:—University of Queen’s College. Calendar. 1886-87. 8vo. Toronto 1886; Examination Papers. 1886. 8vo. Toronto. The University. London :—East India Association. Journal. Vol. XIX. No. 1. 8vo. London 1887. The Association. Odontological Society. Transactions. Vol. XIX. No. 3. 8vo. London 1887. © The Society. Pharmaceutical Society. Calendar. 1887. 8vo. London. The Society. Big eae Society. Journal and Transactions. Vol. XI. No. 4. . 8vo. London 1887. The Society. Royal College of Physicians. List of Fellows, &c. 8vo. London 1887. . The College. Royal Institute of British Architects. Journal of Proceedings. Vol. IIT. No. 8. 4to. London 1887. The Institute. Statistical Society. Journal. Vol. XLIX. Part 4. 8vo. London 1886. The Society. ° University College.. Catalogue of Books in the Medical and Biological Libraries. vo. London 1887. The College. Louvain : —Université Catholique. Annuaire. 1887. 12mo. Lowvain; Théses. 1885-86. 8vo. Louvain; Recherches Analytiques sur la Diffraction de la Lumiére. 4to. Bruzelles 1886; Sur les % 132 Presents. [Feb. 17, Transactions (continued). Racines des Nerfs Pneumo-Gastrique et Spinal. 4to. Brumelles 1863; Sur la Théorie Générale des Lignes Tracées sur une Surface Quelconques. 4to. Bruwelles 1868; Sur la Fonction Collective des Deux Organes de l’Appareil Auditif. Ato. Bruzelles 1868; Liber Memorialis 1834-84. 8vo. Louvain 1887; Choix de Mémoires. Tome XIII. 8vo. Louvain 1887 ; Du Bien au Point de Vue Ontologique et Moral. 8vo. Louvain 186) a - The University. Lyons :—Académie des Sciences, Belles-Lettres et Arts. Mémoires. Classe des Lettres. Tome XXIII. 8vo. Lyon 1885-86; Cartu- laire Lyonnais. Tome I. 4to. Lyon 1885. The Academy. Société d’Agriculture. Annales. Tome VI-VIII. 8vo. Lyon 1884-86. The Society. Société d’ Anthropologie, Bulletin. Tome IV. 8vo. Lyon 1885. The Society. Société Linnéenne. Annales. Tome XXX-XXXI. 8vo. Lyon 1884-85. | The Society. . Marseilles :—Musée d’Histoire Naturelle. Annales. Zoologie. Tome IT. 4to. Marsetlle 1884-85. The Director. Mauritius :-—Société Royale des Arts et des Sciences. Transactions. Vols. XI-X VIII. 8vo. Maurice 1583-86. The Society. Montpellier :—Académie des Sciences et Lettres. Mémoires. Sec- tion des Lettres. Tome VII. Fasc. 3. 4to. Montpellier 1886 ; .. Mémoires. Section de Médecine. Tome VI. Fasc. 1. 4to. Montpellier 1886. The Academy. New York:—American Geographical Society. Bulletin. 1886. No. 2. 8vo. New York. The Society. American Museum of Natural History. Bulletin. Vol I. No. 8. 8vo. New York 1886. : The Museum. Paris:—Ecole des Hautes Etudes. Bibliothéque. Sciences Philo- logiques et Historiques. Fasc. 66-68 (Livr. 1-2). 8vo. Paris 1886. | The Ministére de l’Instruction Publique. Faculté des Sciences. Théses 1886. Nos. 551-577. 8vo. and 4to. Paris, etc. 1886. The Faculty. Vienna :—Kaiserliche Akademie der Wissenschaften. Almanach. 1886. 8vo. Wien; Anzeiger. 1878, Nr. 26-28. 1880, Title and Index. 1881, Nr. 11-13, 18. 1882, Nr. 10-13, 23-27. 1883, Nr. 1-4, 14. 1886, Nr. 25-27. 8vo. Wien; Denk- schriften. Math.-naturw. Classe. Band L. 4to. Wien 1885; Sitzungsberichte. Math.-naturw. Classe. Abth. I. Jahrg. 1885. Nos. 5-10. Jahrg. 1886. Nos. 1-3. 8vo. Wien. Abth. II. Jahrg. 1885. Nos. 4-10. Jahrg. 1886. Nos. 1-2. 8vo. Wien. Abth. III. Jahrg. 1885. Nos. 3-10. 8vo. Wien; Sitzungs- berichte. Philos.-histor. Classe. Jahrg. 1885. Nos. 3-6. 8vo. 1887.] Presents. 135 Transactions (continued). Wien. Register zu den Banden 101-110. 8vo. Wien 1886; Monumenta Conciliorum Generalium. Tom. III. Pars 1. Ato. Vindobone 1886. ' The Academy. Observations and Reports. International Polar Expeditions:—Mission Scientifique du Cap Horn 1882-83. Tome III. 4to. Paris 1886. Ministéres de la Marine et de |’Instruction Publique. * Die Beobachtungs-HErgebnisse der Deutschen Stationen. Band I. Kineua-Fjord. Band II. Siid-Georgien. 2 Vols. 4to. Berlin 1886. The Meteorological Office. Lisbon:—Commission des Travaux Géologiques du Portugal. Recueil d’Etudes Paléontologiques sur la Faune Crétacique du Portugal. Vol. I. 4to. Insbonne 1886. The Commission. London :—Local Government Board. 15th Annual Report. 1885-86. Supplement. 8vo. London 1886. The Medical Officer. Stationery Office. Report of the Voyage of H.M.S. “Challenger.” Botany. Vol. II. Zoology. Vol. XVII. 2 Vols. 4to. London 1886. The Office. New York:—Columbia College. Library. 2nd and 3rd Annual Reports. 8vo. New York 1886. The College. _ Washington :—U.S. Commission of Fish and Fisheries. Report for 1884. 8vo. Washington 1886. The Commission. Baird (A. W), F.R.S. A Manual for Tidal Observations. 8vo. London 1886. The Author. Dubois (A.) Compte Rendu des Observations Ornithologiques faites en Belgique pendant l’Année 1885. 8vo. Bruwelles 1886. The Author. Hunt (T. Sterry), F.R.S. Mineral Physiology and Physiography. Svo. Boston 1886. The Author. Kops (Jan) Flora Batava. Afl. 275-276. 4to. Leiden [1886 ]. The Netherlands Legation. Mueller (Baron von), F.R.S. Iconography of Australian Species of Acacia and Cognate Genera. 1st Decade. 4to. Melbourne 1887. The Author. Prince (C. L.) The Summary of-a Meteorological Journal, 1886. Folio. [Crowborough 1887. | The Author. Saint-Lager (Dr.) Histoire des Herbiers. 8vo. Paris 1885. The Author. Scott (R. H.), F.R.S., and R. N. Curtis. On the Working of the Harmonic Analyser at the Meteorological Office. 8vo. London 1886. The Authors, 134 Prof. H. Hennessy. Problems in [Feb. 24, February 24, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “Problems in Mechanism regarding Trains of Pulleys and Drums of Least Weight for a given Velocity Ratio.” By Henry Hennessy, F.R.S., Professor of Applied Mathe- matics and Mechanism in the Royal College of Science, Dublin. Received February 7, 1887. Highty years have elapsed since Dr. Thomas Young* published a theorem which has since found a place in most of the scientific treatises on mechanism. This theorem states that in order to obtain a given value or velocity ratio by a train of toothed wheels and pinions of which all the pairs are equal, the ratio of the number of teeth in each wheel to the number in each pinion should be as 359 to 100, when the total number of teeth in the train is the least possible. The late Professor Willis has remarked that the rule deduced from this theorem seemed not to have much practical utility, but he illustrates his remarks by referring to the trains of wheels and pinions em- ployed in clockwork. As trains of wheels, pulleys, and drums, are largely employed in many machines whose arrangements ereatly differ from clockwork, and especially in the processes of textile manu- facture, it may be interesting to examine whether there are not other conditions, besides the number of teeth, which may be economised in the transformation of a movement of rotation from a moderate rate of velocity to a very high rate of velocity. As the number of teeth on a wheel or pinion is proportional to the circumference of the pitch- * ‘Natural Philosophy,’ vol. 2, p. 56. 4to. 1807. The preface to this volume is dated March, 1807. + In some spinning machines it is said that the spindles rotate with velocities of from 6000 to 7000 turns per minute, and high velocities are also often required for reels, bobbins, and fliers. Between these rapidly rotating parts of the machines and the prime mover, trains of pulleys, drums, or wheels are usually interposed, the value of each such train depending on the required increase of velocity.—[ Feb. 21, 1887. ] 1887. | Mechanism regarding Trains of Pulleys, &c. 135 circle, it may be understood as giving a rule for deducing the ratio of the diameters of the wheels and pinions so that the sum of all their circumferences shall be a minimum. Although economy of the cir- cumferences of wheels, speed pulleys or drums in a train may not be of much importance, is it not possible that economy of total weight of material employed may be worthy of inquiry ? Reduction of weight in the parts of a machine is not merely economy of materials em- ployed in the structure, but in the case of moving parts it involves economy of work by lessening the resistances due to friction. The following problems have arisen from such considerations, and in all of them, as well as in that studied by Young, if we call m the number of similar pairs of wheels, speed pulleys or drums, C the circumference of a large wheel, &c., and ¢ of a small one in the same train, the velocity ratio or value of the train « will be— w= (Ofe)* = (Bir)* =a", where « represents the ratio of the radii R and r of a large and a small wheel or pulley. In all such problems we have therefore m = log u/log a, and whether the question relates to the volume or circumference of the wheels or pulleys the usual operations of the calculus will in every case lead toa minimum. The volumes or circumferences of pairs of pulleys or wheels with radii having the ratio 2 may in general be expressed in the form Fa = a-+ba+cx’, where a, b, and c are constants. On multiplying this by m we have— Nee Oe ty log # Hence LA oe ane ER | log wu de loge «(log 2)? GE ea ee PANY Fx 2ka logu da® ~ logw «#(loga)? x(log2)? © 2(log#)3 Oy wa n Fu wi diy fag Ke ) ~ loge #(loga)® wloga\loge «(log a)?/) Bilt as BN oe EA ny, dia: low aoe) doa)? ie i 2 o x dev me log: Fe” Boy dix” log x x” log x 136 Prof. H. Hennessy. Problems in _ [Feb. 24, and from the form of F's in these problems F's and Fz are positive, therefore d?V/da* must be always a positive quantity; whence the value of a obtained in all such problems makes V a minimum. Small pulleys carrying cords are usually made solid and approxi- mately cylindrical; in a train of such pulleys the volumes of the large and small cylinders may be denoted by zbR? and zbr?, where b is the common thickness of each cylindrical disk; the total volume of the train will therefore be— V = m7b(R? +72) = mabr?(R2/r?2 +1), or using the preceding notation, ae U KG +22) log log a A GV a eelege (1427) Kd «(log a)? : TS (1+?) =K ? which gives loga = 3(+a~*); this equation is approximately satisfied by making a = 1°895. Hence the ratio of the radii may be practically set down as 19 to 10 for a train of pulleys of minimum volume or least weight of material. In drums the surface carrying the band is broad, and this surface is commonly supported by spokes which radiate from the axle, while sometimes, as in pulleys, the drum consists of a disk with a broad hoop. If the thickness of the hoop and its disk are equal, a problem similar to the foregoing can be easily solved. The question is, in a series of large and small drums if all the large are equal and also all the small, required the ratio of their diameters so that the entire train shall have the least volume for a given velocity ratio. Let ¢ be the uniform thickness of the disks and hoops of the drums, R and 7 the radii of a small and a large disk, b the breadth of the hoops; we shall have for the total volume of the train V = m7[2(R+4+7r)ib+t(R? +72)], when ¢ is so small compared to R, r, and 6, that quantities multiplied by #, &c., may be omitted. The above may be written wrt _ U Bits log [2(e-+1)b/r-+a2 +1], which gives, by the usual process of making dV/dx = 0, 2(e+1)db/r+e+1 2u(b/r +a) los a = 1887.] Mechanism regarding Trains of Pulleys, &c. 137 In the particular case where r is a multiple of b, or r = nb, ton’ 2@+D+m@r+D) Roe eee ey mien i 9% = 1, | Ge bk) 2 OSes rE ra This equation gives = 2°21 nearly, or practically a ratio of 11 to 5 for the diameters of the large and small drums in such a train as has been indicated. Although it is manifest that the volume of a single pair of pulleys with the same velocity ratio as this train of five pairs would be con- siderably greater, it may be interesting to make the comparison. If R' be the radius of the large pulley in the single pair, and as before y of the small pulley, then R’ = ur, and the volume of the pair V' = wi(v?+1)r?. As before, the volume of the train is V = ant(a*+1)r?, eae ek in aD (ot Vv n(a?+1) n(xv?+1) If # = 19 and n = 5, we shall have V'/V = 26°64, or the volume of a single pair would be more than twenty-six times the volume of a train of five pairs with the same velocity ratio. Another solution can be easily found if a train of drums were so constructed that the volume of the spokes supporting the hoop of each drum would be half the volume of a complete disk, in this case Vv mrt [2(R+r)b+4(R? +7") | log u b mrt | 2(e-+ 1)- +4(a?+1)] Noes fart and if we make 6 = 7, this gives, from dV/dz = 0, ee Ee emery which is satisfied by making « = 2-55, or the diameters of the large drums would be to those of the small drums in the ratio of 51 to 20 in a train of least weight of drums such as here described. If in this case 6 in all the drums instead of being equal to r was equal to the greater radius R, we would have evidently V = mrr*t[2(a+1)¢+4(2?+1)] log u = $77°t[52°2+4r+1] log x f 1388 Hon. R. Abercremby. On the Relation between [Feb. 24, and when dV /dx = 0, 5a®°+4e+1 08? = Tos de This will be satisfied by making z somewhat less than 1:9, so that in this case the ratio of the diameters of the drums would be a little less and very close to the ratio found for the pulleys. In order to illustrate the foregoing problems a model of a train of pulleys and another of a train of drums made of brass were con- structed by Mr. Yates. In the train of pulleys all the large ones are 1:9 inches in diameter, and all the smallare 1 inch. Each of the former weighs 2°61 oz., and each of the latter 1:058 oz.; as there are five pairs their total weight is 18°340 oz., while they give a velocity ratio of (1°9)° = 24-761, or a little more than 243. The train of drums consists of large ones with diameters of 2°55 inches and small of 1 inch, the hoops are in all 0'5 inch in breadth, and the spokes are half the volume of a complete disk. The weights of the large drums are each 3°386 oz., of the small 0-811 oz. There are four pairs of drums, and their total weight is 16°788 oz., or little more than 1 lb. The velocity ratio of this train is (51/20)* = 42-2825, or a little more than 424. II. “On the Relation between Tropical and Extra-Tropical Cyclones.” By Hov. RatpH ABERCROMBY, F.R. Met. Soc. Communicated by R. H. Scott, M.A., F.R.S. Received February 7, 1887. (Abstract. ) The conclusions as to the relation of tropical to extra-tropical cyclones which the author has derived from the researches of which this paper gives an account, may be stated thus :— All cyclones have a tendency to assume an oval form; the longer diameter may lie in any direction, but has a decided tendency to range itself nearly in a line with the direction of propagation. The centre of the cyclone is almost invariably pressed toward one or other end of the longer diameter, but the displacement may vary during the course of the same depression. Tropical hurricanes are usually of much smaller dimensions than extra-tropical cyclones; but the central depression is much steeper, and more pronounced in the former than in the latter. Tropical cyclones have less tendency to split into two, or to develope secondaries, than those in higher latitudes. | A typhoon which has come from the tropics can combine with a 1887. ] Tropical and Extra-Tropical Cyclones. 139 cyclone that has been formed outside the tropics, and form a single new, and perhaps more intense, depression. No cyclone is an isolated phenomenon; it is always related to the general distribution of pressure in the latitudes where it is generated. An area of excessive pressure, with unusually fine weather, precedes most cyclones. Though the nature and origin of this high barometer is very obscure, the general character of the formation, and the weather associated with it, appear to be the same everywhere. In all latitudes a cyclone which has been generated at sea appears to have a reluctance to traverse a land area, and usually breaks up when it crosses a coast line. After the passage of a cyclone in any part of the world, there is a remarkable tendency for another to follow very soon, almost along the same track. The velocity of propagation of tropical cyclones is always small; and the average greatly less than that of Huropean depressions. There is much less difference in the temperature and humidity before and after a tropical cyclone than in higher latitudes. The quality of the heat in front is always distressing in every part of the world. The wind rotates counter-clockwise round every cyclone in the Northern Hemisphere, and everywhere as an ingoing spiral. The amount of incurvature for the same quadrant may vary during the course of the same cyclone; but in most tropical hurricanes the incurvature is least in front, and greatest inrear; whereas in Hngland the greatest incurvature is usually found in the right front. Some observers think that broadly speaking the incurvature of the wind ° decreases as we recede from the Equator. The velocity of the wind always increases as we approach the centre in a tropical cyclone; whereas in higher latitudes the strongest winds and steepest gradients are often some way from the centre. In this peculiarity tropical cyclones approximate more to the type of a tornado; but the author does not think that a cyclone is only a highly developed whirlwind, as there are no transitional forms of rotating air. The general circulation of a cyclone, as shown by the motion of the clouds, appears to be the same everywhere. All over the world, unusual coloration of the sky at sunrise and sunset is observed, not only before the barometer has begun to fall at any place, but before the existence of any depression can be traced in the neighbourhood. Cirrus appears all round the cloud area of a tropical cyclone, instead of only round the front semicircle, asin higher latitudes. The stripes of cirrus appear to lie more radially from the centre in the tropics, than tangentially, as indicated by the researches of Ley and Hilde- brandsson in England and Sweden respectively. 140 On Tropical and Extra-Tropical Cyclones. [Feb. 24, The general character of the cloud all round the centre is more uniform in than out of the tropics; but still the clouds in rear are always a little harder than those in front. Everywhere the rain of a cyclone extends farther in front than in rear. Cyclone rain has a specific character, quite different from that of showers or thunderstorms; and this character is more pronounced in tropical than in extra-tropical cyclones. Thunder or lightning is rarely observed in the heart of any cyclone, and the absence of electrical discharge is a very bad sign of the weather. Thunderstorms are, however, abundantly developed on the outskirts of tropical hurricanes. Squalls are one of the most characteristic features of a tropical cyclone, where they surround the centre on all sides; whereas in Great Britain, squalls are almost exclusively formed along that portion of the line of the trough which is south of the centre, and in the right rear of the depression. As, however, we find that the front of a British cyclone tends to form squalls when the intensity is very great, the inference seems justifiable that this feature of tropical hurricanes is simply due to their exceptional intensity. A patch of blue sky, commonly known as the ‘“ bull’s-eye,” is almost universal in the tropics, and apparently unknown in higher latitudes. The author’s researches show that in middle latitudes the formation of a ‘‘bull’s-eye” does not take place when the motion of translation is rapid; but as this blue space is not observed in British cyclones when they are moving slowly, it would appear that a certain intensity of rotation is necessary to develope this phenomenon. The trough phenomena,—such as a squall, a sudden shift of wind, and change of cloud character and temperature, just as the barometer turns to rise, even far from the centre—which are such a prominent feature in British cyclones, have not been even noticed by many meteor- ologists in the tropics. The author, however, shows that there are slight indications of these phenomena everywhere; and he has collated their existence and intensity with the velocity of propagation of the whole mass of the cyclone. Every cyclone has a double symmetry. One set of phenomena, such as the oval shape, the general rotation of the wind, the cloud ring, rain area, and central blue space, are more or less related to a central point. Another set, such as temperature, humidity, the general character of the clouds, certain shifts of wind, and a particular line of squalls, are more or less related to the front and rear of the line of the trough of a cyclone. The author’s researches show that the first set are strongly marked in the tropics, where the circulating energy of the air is great, and the velocity of propagation small; while the second set are most 1887. | A Thermal Telephone Transmitter. 141 prominent in extra-tropical cyclones, where the rotational energy is moderate, and the translational velocity great. The first set of characteristics may conveniently be classed together as the rotational; the second set as the translational phenomena of a cyclone. Tropical and extra-tropical cyclones are identical in general cha- racter, but differ in certain details, due to latitude, surrounding pressure, and to the relative intensity of rotation or translation. II. “A Thermal Telephone Transmitter.” By Prof. GEORGE Forbes. Communicated by Lorp RAYLEIGH, D. Cll. Sec: R.S. Received February 12, 1887. We have had so much evidence of the sensitiveness of the Bell telephone receiver to the minutest changes of current, that we have ceased to be surprised at any transmitter which responds to the sounds of articulate speech. But, in the instrument now shown, it was so extremely unlikely that sensible variations of current could be produced with sufficient rapidity, that even now there is perhaps some interest attached to the experiment. A wooden cylinder was used closed at one end. A saw cut was made across the diameter of the closed end, making a fine slit. In the slit was stretched a platinum wire, 0:001 inch diameter and 2 inches long, with its ends connected by copper wires through the primary of an induction coil to a battery sufficiently powerful to make the platinum wire red hot. On connecting the secondary circuit with a receiving telephone in a distant room and speaking into the wooden cylinder, the words are reproduced and heard in the tele- phone. Hach vibration of air in the slit cools the platinum wire, diminishing its electrical resistance, and increasing the electric current. The words transmitted are not quite perfect, the higher harmonics being wanting. It requires some attention to make out all the words of a sentence. A brass cylinder instead of the wooden one, and a Wollaston platinum wire of excessive fineness have been used without materially altering the clearness of the articulation. Platinum foil has hitherto given no sound of the voice. The slit in the brass instrument is made of glass to prevent the short-circuiting and destruction of the platinum wire. Wires from one to three inches in length have been used. The longest ones are best. No distinct articulation is heard if the wire be not red hot. The hotter the wire the better is the articulation. An adjustible siit was tried and the narrow slit gave the best results. Mr. Preece some years ago used the expansion and con- traction of a fine platinum wire to act on a diaphragm, and so serve 142 ,; Presents. [Feb. 24, asareceiver. The articulation seems to have been about the same in quality as when the new transmitter is used with a Bell receiver. These new experiments bear out all that Mr. Preece said about the rapidity of variation of temperature which can be produced in a fine platinum wire. They may also be perhaps of some interest from other points of view; but they are not likely to lead to any results of practical importance. It is probable from the theory of the instru- ment that the tones are raised an octave, as is also the case in the Preece receiver. me Presents, February 24, 1887. Transactions. Baltimore: — Johns Hopkins University. Studies. Historical and Political Science. Fifth Series. No. 3. 8vo. Baltimore 1887; 11th Annual Report. 8vo. Baltimore 1886. The University. Berlin :—Physikalische Gesellschaft. Fortschritte der Physik im Jahre 1879. Jahrg. XXXV. 8vo. Berlin 1885-86. The Society. Cambridge, Mass.:—Harvard College. Annual Reports, 1885-86. Svo. Cambridge, Mass. 1887. The College. Delft :—Ecole Polytechnique. Annales. Tome II. Livr. 3-4. 4to. Leide 1886. The School. Géttingen:—Konigl. Gesellschaft der Wissenschaften. Nach- richten. 1886. Nro. 1-20. 8vo. Gottingen. The Society. Heidelberg :—Naturhistorisch-Medicinischer Verein. Verhand- lungen. Band IIT. Heft 3. 8vo. Heidelberg 1884. The Association. University. Almanach. 1886. 12mo. Heidelberg; Inaugural- Dissertationen, &c., 1886. 8vo. Heidelberg, &c.; Urkundenbuch der Universitat Heidelberg. 2 Vols. Large 8vo. Heidelberg 1886; Die Alteste Zeit der Universitit Heidelberg 1386-1449. Svo. Heidelberg 1886; Festrede zur Fiinfhundertjaihrigen Jubelfeier. 4to. Heidelberg 1886; Festschrift der Badischen Gymnasien. 4to. Karlsruhe 1886; Beitrage zu einer Biogra- phie Ottheinrichs (Festschrift). 4to. Heidelberg 1886; Ueber die Lehenbiicher der Kurfiirsten und Pfalzgrafen Friedrich I. und Ludwig V. 4to. Karlsruhe 1886 ; Ruperto-Carola: illustrirte Fest-Chronik der V. Sacularfeier der Universitat Heidelberg. Folio. Heidelberg 1886. The University. Liége :—Société Royale des Sciences. Mémoires. Sér. II. Tome 13. 8vo. Bruwelles 1886. The Society. London :—General Medical Council. Third Report of the Statistical Committee. 8vo. London 1886. The Council. 1887. | Presents. ) 143 Transactions (continued). Geological Society. Quarterly Journal. Vol. XLIII. No. 169. 8vo. London 1887. The Society. Institution of Civil Engineers. Minutes of Proceedings. Vol. LXXXVIT. 8vo. London 1886. The Institution. Royal Microscopical Society. Journal. 1887. Part 1. 8vo. London. The Society. St. Bartholomew’s Hospital. Reports. Vol. XXII. 8vo. London 1886. . The Hospital. Society of Biblical Archeology. Proceedings. Vol. II. 8vo. London 1880. The Society. Middelburg :—Zeeuwsch Genootschap der Wetenschappen. Verza- melingen. 1885. 8vo. [ Middelburg. | Mr. A. H. White. Moscow :—Musée Ethnographique Daschkow. Recueil de Matéri- aux pour l’Hthnographie. [| Russian] Livr. 1-2. 8vo. Moscow 1885-87. Guide to the Museum. [Russian] Sm. 8vo. Moscow 1886; Guide to the Collection of Portraits. [Russian] Sm. 8vo. Moscow 1887. The Museum. Newcastle-upon-Tyne :—North of Hngland Institute of Mining and Mechanical Engineers. Transactions. Vol. XXXVI. Part 1. 8vo. Newcastle 1887. The Institute. Paris :—Société Mathématique de France. Bulletin. Tome XIV. No. 5. 8vo. Paris 1886. The Society. Tokio:—Imperial University of Japan. Calendar. 1886-87. 8vo. ' Tokyo 1886. The University. Utrecht: — Nederlandsch Gasthuis voor Ooglijders. Verslag. _ XXVII. 8vo. Utrecht 1886. The Hospital. Vienna :—Verein der Geographen an der Universitat. Bericht iiber das XI. Vereinsjahr. 8vo. Wien 1886. The Association. Journals. Annales des Mines. Sér. VIII. Tome 10. Livr. 5. 8vo. Paris 1887. Ecole des Mines, Paris. Asclepiad (The) Vol. IV. No. 13. 8vo. London 1887. Dr. Richardson, F.R.S. Bullettino di Bibhografia e di Storia delle Scienze Matematiche e Fisiche. Marzo-Aprile, 1886. 4to. Roma 1886. The Prince Boncompagni. Horological Journal. Vol. XXIX. No. 342. 8vo. London 1887. , The Horological Institute. Indian Antiquary (The) Vol. XV. Part 190. 4to. Bombay 1886. The Hditors. New York Medical Journal. Vol. XLV. No. 5. 4to. 1887. The Editor. VOL. XLII. 7 L 144 Presents. Journals (continued). Revista do Observatorio. Anno Il... Num. 1. 8vo. Rio de Janeiro 1887. The Observatory of Rio. Bonney (T. G.), F.R.S. On some Rocks from the neighbourhood of Assouan. 8vo. Hertford 1886; Report on the Rocks collected by H. H. Johnston, from the upper part of the Kilima-njaro massif. 8vo. London {1886]; Remarks on the Stratified and Igneous Rocks of the Valley of the Meuse in the French Ardennes. 8vo. [| London 1886. | The Author. Conwentz (H.) Die Flora des Bernsteins. Band II: Die Angio. spermen des Bernsteins. 4to. Danzig 1886. Prof. Conwentz. Dawson (Sir W.), F.R.S. On Rhizopods in the Erian (Devonian) Period in America. 8vo. Chicago 1886. The Author. Dimmock (G.) Dimmock’s Special Bibliography. Nos. 1-3. 8vo. Cambridge, Mass. 1878-79 ; “‘ Psyche,” a Journal of Entomology. Vols. ITI-IV. Nos. 101-112. Sm. 4to. Cambridge, Mass. 1882-83. With Six Entomological Excerpts. 8vo. and 4to. 1875-86. Mr. G. Dimmock. Jones (T. R.), F.R.S., and J. W. Kirkby. On Carboniferous Ostra- coda from the Gayton Boring, Northamptonshire. 8vo. Hertford 1886 ;—and C. D. Sherborn. On the Microzoa found in some Jurassic Rocks of England. 8vo. Hertford 1886 ;—and H. B. Holl. Notes on the Paleozoic Bivalved Entomostraca. No. XXII. 8vo. London 1886. Prof. T. R. Jones, F.R.S. Nikitin (S.) Die Cephalopodenfauna der Jurabildungen des Gou- vernements Kostroma. 4to. St. Petersburg 1884; The Jurassic Formation between Rybinsk, Mologa, and Myszkin. [ Russian | 8vo. St. Petersburg 1881; Brochure on Darwinism and Paleon- tology. [Russian] 8vo. St. Petersburg [1882]; Four Geological Excerpts. 8vo. and 4to. The Author. Pickering (H. C.) Heights of the White Mountains. 8vo. [1887.] ; The Author. Prince (C. L.) Summary of a Meteorological Journal. 1885. Folio. [ Crowborough 1886. | The Author. Puech (L.) Mémoire sur les Grottes de Sarxgel. [With Photo- graphs.| 4to. Saint-Affrique 1886. The Author. Sasse (H.) Das Gahlengesetz in der Volker-Reizbarkeit. Statistik der neueren Geschichte von Frankreich. 8vo. Brandenburg 1877. | The Author. Unwin (W.C.), F.R.S. Formule for the Flow of Water in Pipes. Ato. Manchester 1886. The Author. Wright (T.), F.R.S. Monograph on the Lias Ammonites of the British Islands. 4t0. London 1878-86. So tate Bequeathed by the Author. 1887.] Candidates for Election. 145 March 3, 1887. Professor G. G. STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. In pursuance of the Statutes the names of the Candidates recom- mended for election into the Society were read from the Chair as follows :— Andrews, Thomas, F.R.S.E. Atkinson, Professor Edmund, Ph.D. Bottomley, James Thomson, M.A. Buchanan, John Young, M.A. Burbury, Samuel MHawkesley, M.A. Buzzard, Thomas, M.D. ' Cameron, Sir Charles Alexander, M.D. Carnelley, Prof. Thomas, D.Sc. Cash, J. Theodore, M.D. Corfield, Professor William Henry, M.D. Davis, James William, F.G.S. Denton, John Bailey, M.I.C.E. Dickinson, William Howship, M.D. Douglass, Sir James Nicholas, M.1.C.E. Ewart, Professor J. Cossar, M.D. Ewing, Professor J. A., B.Sc. Forbes, Professor George, M.A. Foster, Professor Sir Balthazar Walter, F.R.C.P. Gowers, William Richard, M.D. Halliburton, William Dobinson, M.D. Hinde, George Jennings, Ph.D. Hyde, Henry, Major-General, R.E. Jervois, Sir William Francis Drummond, Lieut-General, R.E. VOL. XLII. Kennedy, Professor Alexander Blackie William, M.I.C.H. Kent, William Saville. King, George, M.B. Kirk, Sir John, M.D. Lansdell, Rev. Henry, D.D. Latham, Peter Wallwork, M.D. Lea, Arthur Sheridan, D.Sc. Lodge, Professor Oliver Joseph, D.Se. Lyster, George Fosbery, M.I.C.E. Matthey, Edward, F.C.S. Maw, George, F.L.S. Milne, Professor John, F.G.S. Ord, William Miller, M.D. Palmer, Henry Spencer, Colonel, R.E. Parker, Professor T. Jeffery. Pedler, Prof. Alexander, F.C.S. Pickard-Cambridge, Rev. Octa- vius, M.A. Pickering, Professor Spencer Um- freville, M.A. Poynting, Professor John Henry, B.Se. Pritchard, Urban, M.D. Ramsay, Professor William, Ph.D. Seebohm, Henry, F.L.S: Smith, Willoughby. Snelus, George James, F.C.S. Sollas, Professor William Johnson, D.Sc. M 146 Mr. W. F. R. Weldon. Ona [Mar. 3, Stevenson, Thomas, M.D. Tomlinson, Herbert, B.A. Teale, Thomas Pridgin, F.R.C.S. | Topley, William, F.G.S. Tenison-Woods, Rev. Julian H., | Ulrich, Professor George (ome M.A. Frederic, F.G.S. Thin, George, M.D. Walsingham, Thomas, Lol Tidy, Professor Charles Meymott, | Whitaker, William, B.A. M.B. Yeo, Professor Gerald F., M.D. Todd, Charles, M.A. The following Papers were read :— I. “Preliminary Note on a Balanoglossus Larva from the Bahamas.” By W. F. R. Wetpon, M.A., Fellow of St. John’s College, Cambridge. Communicated by Prof. M. Foster, Sec. R.S. Received February 15, 1887. In October last, during a visit to the Island of Bemini, on the western edge of the Bahama bank, an organism was constantly found in the tow-net which closely resembled the larva of Balanoglossus recently described by Bateson.* In the youngest stage observed, this creature has an elongated cylindrical body (about 0°8 mm. long by 0:4 mm. broad) with rounded ends. At the anterior extremity are two eye-spots, while near the posterior is a large and powerful ring of cilia. An anterior region is separated from the rest by a deep transverse groove; more than this cannot be made out by examination of entire specimens.t A little later, a second shallower groove appears behind the first, marking off a smaller middle region of the body from the larger anterior and posterior divisions. An idea of the shape of the body, just before the appearance of the second transverse groove, may be gathered from the nearly median longitudinal section (fig. 1). In this section the mouth is seen to lie in the first transverse groove, on the ventral side of the hody ; it leads to a well-developed alimentary canal, ending ina median posterior anus, not seen in the figure. On each side of the alimentary canal lie two sections of body cavity; the first (fig. 1, II) can hardly be spoken of as a cavity, its lumen being never con- spicuous, and often obliterated ; behind this is a well-developed pos- terior cavity (III). The body cavities of the two sides are separated * ‘Roy. Soc. Proc.,’ vol. 38, 1885, p. 23; and ‘Quart. Journ. Microsc. Sci.,’ 1885 and 1886. + I regret that my observations on the living larva are most imperfect. Owing to my want of experience in protecting delicate organisms, after capture, from a tropical sun, I was frequently obliged to preserve the material obtained in an open boat, where microscopic work was impossible. Balanoglossus Larva from the Bahamas. 147 1887.] Ere. 1. from one another in the middle line by a considerable interval, and the posterior pair especially leave a considerable part of the blastoccel The anterior nearly solid body cavities unoccupied (fig. 2, Bl.). Fie. 2. Nt Mf | are separated dorsally by a forward process of the posterior cavities ; so that a section so near the middle line as that drawn in fig. 1 does not cut them dorsally at all. The anterior region of the body in front of the great transverse M 2 148 Mr. W. F.R. Weldon. Ona [Mar. 3, groove is occupied by a single unpaired body cavity (fig. 1, I), which obliterates the blastoccel. This cavity is traversed by a number of longitudinal ‘“‘mesenchymatous’’ muscles (Mc.), and carries on its floor a glandular organ (GiJ.), near which opens, asymmetrically, a short canal, which runs to the middle dorsal line, where it communi- cates with the exterior bya pore(P.). Immediately beneath the gland is a forwardly directed diverticulum of the gut (Ch.). It seems impossible to avoid identifying these structures with the proboscis gland and pore of Balanoglossus, and the subjacent “noto- chord’’; while the anterior paired body cavity represents the collar cavity, the posterior the trunk cavity, of the normal Balanoglossus larva. A confirmation of this view is given by the appearance, at a slightly Jater date, of a single pair of rudimentary gills (fig. 2, Br.). The ectoderm of the larva, up tothe point at which the gills appear, is very thick (figs. 1 and 2), and contains many mucus and other glandular cells; while beneath the eye-spots is a well-developed “ Scheitelplatte,” and beneath the general ectoderm a well-formed embryonic nervous system, the details of which I reserve for a later paper. Just after the development of the gill-slits, there appears to be much variation in the conduct of the larve obtained; some exhibit indications of a normal development; the majority, however, begin from this point to undergo a gradual process of degeneration, accom- panied by considerable increase in size. The shape of the most degenerate larva obtained may be gathered from the nearly median longitudinal section (fig. 3) ; where the coliar Exe.) 3: 1887. ] Balanoglossus Larva from the Bahamas. 149 groove is seen to have disappeared altogether, while that behind the proboscis has become much shallower. The external appearance is complicated by the formation, on each side of the proboscis, of a (I)-shaped groove, the middle limb of which communicates with the post-proboscidean groove, while the margins of all the limbs are pro- vided with short, broad tentacles. The arrangement of this groove is indicated by the shading between dotted lines in fig. 3. Sections show that the mesoblastic organs have undergone con- siderable reduction, both relative and, in some cases, absolute. The proboscis cavity is smaller (fig. 3, 1); its walls are thinner, and its muscles fewer. The notochord beneath it has quite disappeared ; the collar cavities have disappeared; while the trunk cavities are small and thin-walled (fig. 3, III). No trace of gill-pouches remains. The ectoderm is much thinner, and contains hardly a trace of any nervous structure except the much diminished “Scheitelplatte” (Sch.), on which the eye-spots still persist. | In connexion with this degeneration of the tissues, it may be noticed that many cells, possibly phagocytes, are present in the blastoccel at earlier stages (fig 2, Ph. ?). I was not able during my stay at Bemini to follow this creature further; but at Nassau, New Providence, in the middle of the Bahama bank, I observed, during four months, a similar series of changes in a much larger larva. This larva was first obtained at a period just before the development of the tentacular apparatus, and after the disappearance of the collar groove (if this ever existed). The collar and trunk cavities were both well developed, and the proboscis cavity, with its gland and pore, was as in the youngest Bemini forms. Eye- spots were present, and there was a well-developed cutaneous nerve plexus. In this form degradation was followed to a much fuller extent, till the ectoderm was (except on the well-developed tentacles and beneath the cilia) a mere flattened epithelium; the trunk cavity was a minute solid rod beneath the ciliated ring; the collar cavity disappeared, and the reduction of the proboscis cavity was carried much further than in the Bemini form. I hope to publish a fuller account of both forms in a subsequent paper. In the meantime, it is submitted that there is fair ground for the belief that the organisms described are Balanoglossus larve, which from some cause or other have been unable to develop adult characters, and have therefore varied. Independent evidence shows that a probable cause may be the compulsory shifting of the larve into deep water by the joint action of currents and winds.* If this be admitted, four things follow :—First, that, at least in some cases, the transmission by a larva of hereditary changes is only * These larvee were practically al] caught outside the 100-fathom line. 150 Messrs. G. C. and P. F. Frankland. [Mar. 3, possible on the application of the stimuli afforded by particular surroundings; secondly, that some larve, in the absence of these stimuli, but im conditions otherwise favourable, are highly variable ; thirdly, that the variations produced by a given change in the environ- ment may be of an uniform and definite character; and lastly, that these changes may result, not in the modification of ancestral organs, but in the hypertrophy of those which are purely larval. The last of these considerations leads to the hope that a further investigation of similar cases may afford a criterion by which to interpret larval histories in general. EXPLANATION OF THE FIGURES. Fig. 1.—Lateral longitudinal section (nearly median) through a young Bemini larva, just before the appearance of the collar-fold. Fig. 2.—Transverse section through the trunk of a Bemini larva, at the time of the greatest development of the gill-pouches. Fig. 3.—Nearly median longitudinal section through a degenerate Bemini larva. The arrangement of the tentaculiferous grooves is indicated by shading within the dotted lines. Reference Letters.—An., anus; Bl., blastocel; Br., branchial pouch; Cz., “ noto- chord” of Bateson; Ci., cilia; Gl., proboscis gland; M., mouth; We., “mesenchym”’ of proboscis cavity; P., proboscis pore; Ph.?, cells of blastocel, possibly phagocytes; Sch., “scheitelplatte”; I, II, III, body cavities of proboscis, collar, and trunk respectively. II. “ Studies of some New Micro-organisms obtained from Air.” By G. C. FRANKLAND, and PERcy F. FRANKLAND, Ph.D., B.Sc. (Lond.), F.C.S., F.LC. Communicated by EH. Ray LANKESTER, M.A., F.R.S., Professor of Zoology, University College, London. Received February 15. 1887. (Abstract. ) In previous communications to the Royal Society by one of the authors,* details have been given of a number of experiments on the presence of micro-organisms in the atmosphere. In these investiga- tions a solid culture medium was employed, which not only greatly facilitated their enumeration, but also presented them in an tsolated condition. In this manner the authors have met with a number of * 1. “The Distribution of Micro-organisms in Air,” ‘ Roy. Soc. Proc.,’ vol. 40, p- 509; 2. “A New Method for the Quantitative Estimation of the Micro- organisms present in the Atmosphere,” idid., vol. 41, p. 443; 3. “ Further Experi- ments on the Distribution of Micro-organisms in Air by Hesse’s method,” 7bid., p. 446. 1887.] New Micro-Organisms obtained from Air. 151 different varieties of aérial micro-organisms, which have hitherto remained either unknown or undescribed. They have therefore undertaken the characterisation of a number of these organisms by growing them in various cultivating media and observing the different appearances which they subsequently exhibit, by studying them microscopically in stained and unstained preparations, and by culti- vating them on gelatine-plates, and describing the colonies to which they give rise. They have likewise made a number of drawings to illustrate the appearauces which they present under the various exami- nations to which they have submitted them. To further facilitate their identification the authors have provisionally given them names, by which they have endeavoured to represent some of their most striking individualities. The authors venture to hope that by thus characterising some of the organisms most prevalent in the atmosphere, they may prove of assistance in those investigations which have for their object the study of the particular physiological changes which are brought about by specific micro-organisms. The following is a list of the micrd-organisms described :— Micrococcus carnicolor. Bacillus plicatus. a albus. 2 chlorinus. ty gigas. » polymorphus. i chryseus. 2 profusus. fi candicans. Ks pestifer vermicularis. Streptococcus liquefaciens. < subtilis minor. Sarcina liquefaciens. | » subtilis cereus. Bacillus aurescens siccus. Saccharomyces rosaceus. i aureus. a liquefaciens. 95 citreus. Mycelium fuscum. In addition to these varieties a description has been given for the sake of comparison of some aérial micro-organisms which were obtained by one of the authors from Dr. Koch’s laboratory in Berlin. ‘These are— Micrococcus rosaceus. - Bacillus subtilis. Sarcina lutea. 9 (Micrococcus) prodi- » aurantiaca. giosus. 152 Mr, Wei Preete, . On rne a. [Mar. 3, III. “On the Limiting Distance of Speech by Telephone.” By Wiuu1amM Henry PREECE, F.R.S. Received February 17, 1887. The law that determines the distance to which speaking by tele- phone on land lines is possible, is just the same as that which de- termines the number of currents which can be transmitted through a submarine cable in a second. The experimental evidence upon which this law is based was carried out in 1853 by Mr. Latimer Clark (whose assistant I then was). The experiments were made by me in the presence of Faraday; many were his own; he made them the subject of a Friday evening discourse at the Royal Institution, January 20, 1854, and they are published in his ‘ Researches’ (vol. 3, p- 508). They received full mathematical development by Sir William Thomson in 1855 (‘Roy. Soc. Proc.,’ May 24), who determined the law, the accuracy of which was proved by Fleeming Jenkin and by Cromwell Varley, and the 110,000 miles of cable that now lie at the bottom of the ocean afford a constant proof in their daily working. | Hockin reduced Thomson’s law to the following series :— @ = O(1— 25 (8)¢/e—(2)# 44 (2) /a— (2) 'e/ay &e.}), which allows it to be expressed by the following curve (1) :— Now a is a time-constant dependent on the conditions of the circuit, invariable for the same uniform circuit but differing for different circuits. It represents the time that elapses from the instant contact is made at the sending end to the instant that the current begins to appear at the receiving end. It is given by the following equa- tion :— a = Bkri’, B being a constant dependent principally on the units used; & the 1887.| Limiting Distance of Speech by Telephone. 153 inductive capacity per unit length (mile or knot); r the resistance per unit length, and / the length in miles or knots. a, therefore, limits the number of vibrations per second that can be sent through any circuit. If a be 0°196 second, as it was in the French Atlantic cable of 1869,* 2584 knots long, then it is impos- sible to send 5:1 currents per second through that cable; but it would be possible to send 5 or 24 complete reversals per second. Moreover, as the number of reversals varies inversely with the square of the length, it shows that such a cable if of 100 miles length would allow 1562 reversals to pass through it. It is necessary to remark that these expressions involve no mention of H.M.F., or of current, and therefore the number of reversals which can be produced at the end of a wire is quite independent of the impressed H.M.F., and therefore of the strength of the current. But the number of reversals is dependent upon the sensitiveness of the apparatus used to receive the currents, for if we use an instrument which will respond to a cur- rent indicated by the full line, we get two currents per second ; and if we use an instrament which will respond only to the dotted line, we get only one current in two seconds, which is about the current used. with delicate relaysin this country. This is why such discordant results are obtained by different observers who attempt to measure the velocity of currents of electricity. It is also why the telephone is such an admirable instrument for research—for it is sensitive to the least increment or decrement of current. | Before proceeding with this inquiry it was necessary to determine very accurately the inductive capacity of overhead and underground wires. This was done with great care on very dry days in different parts of the country by means of a. Thomson mirror galvanometer and a standard condenser. The results come out as follows :— Capacity Resistance per mile per mile microfarads. B. A. ohms. MMC FEET CMON UIE! coo eel cle t sose oe Fe Sue ccs wiwas 0°0168 12°0 * No. 123 copper wire ..... Wrap arte 0°0124 5°7 Gutta-percha-covered wire in iron pipes . a 0 °2500 23 °0 Gutta-percha-covered wire in cables.......... 0° 2900 10°25 The capacity can be calculated from the following formula (also due to Sir William Thomson) :— l ~~ Zilog (4h/d)’ * Fleeming Jenkin, ‘ Electricity and Magnetism,’ p. 331. 154 Mr. W. H. Preece. On the [Mar. 3, where d is the diameter of the wire and h the height above the eround. Taking h at 500 cm. and d; at 0°243 cm., the capacity comes out for 124 wire at 0°0113 instead of 0:0124 microfarad per mile. The cause of this difference is referred to further on. It then became necessary to determine the speed of the current through wires of different lengths, resistances, and capacities. A multiplex distributor—such as we are now using in the Post Office—enables this to be done with great accuracy. At each station a circle is broken up into 162 sections, and an arm in connexion with the line wire carrying a brush sweeps over these sections and makes contact. This arm can be made to rotate at any speed. If it makes three revolutions per second it will make the duration of each contact zigth of a second. Now the two distributors are kept running in absolute synchronism, so that the brush at each station always rests ‘simultaneously on corresponding sections. The sections at one station can be placed in contact with the battery, and those at the other station with a galvanometer or other sensitive apparatus. If the cur- rent traversed the wire instantaneously then it would appear on the Same section at the same time on the galvanometer; but the current is always retarded, and the amount of retardation or the value of a can be measured and the curve of arrival and cessation drawn by watching the indications of the galvanometer on each succeeding section. The following table summarises a large number of experiments that have been made in different parts of the country, and on different lines, to determine by observation the connexion that exists between speed of current, distance spoken through, resistance, and capacity. The maximum current, or the crest of the wave, was observed. This was equivalent to 0:003 ampere. It will be seen that the limiting distance through which it is possible to speak varies inversely with the speed of the current, and that the speed of the current varies inversely with the product of the total resistance and the total capacity of the circuit. Hence we can say that the number of reversals that it is possible to send through any circuit varies inversely with the product of the total resistance (R) and the total capacity (K), or the limiting distance S = KR x constant. . . .. =. (I) This is only another form of Thomson’s law for K = lk, and i = ty, and .. S = kr? x constant. It is seen that when the speed of the working current was 0001” speaking was perfect, 0:002” speaking was good, 0°003” speaking was fair, 0004" speaking was difficult. 155 Distance of Speech by Telephone. ing t wm L "MOIYBSADAUOD B LO Arxeo 04 oTqe ysnl yng ‘yom Sut -ywodg ‘ouoydoeey, T[aq-temoy vE00-0 "poyeTNoTBo **poteA0D corer sees UOTMIUBN PUB QPL [rrcstsuadg f CMG ‘ aectoa PPL pur ZL “SON ce ex | re we) Y ——=> be “HOTJVSLOATON B = aes F "poyepnoyeo \ { Iz |****podsaop ] °**48v09 reece eee TORgGOMOT, PUB Ede eavudere pemouog || ree00.e ee 0g [rts uedg J 4804 MON || UOpUuOTT PPT pute yPT ‘so g dg "Ax0q0%y * joodoy4ae FT -s17es Suryvodg ‘4mo.ato poattop : re eeereeeeneT 110949099 UI ‘eoURISISeEL smyO QOOT (pei fice \ 9. L18¢ 680-61 Lerche. +9 MA ae 0} YOMAIVAA ‘u1e4sfs JO syoudeut-oajooya oyerpout 9100-0 Té8-€9 Had@ pels eal Soe euoydoloy, o[3svomen -loyur ¢ ‘souoydeyay, T]9q-1aMo4y STSBOMON Pid “ATIAOJORIS TIVES “paqepnoyeo Gz.0. = |S Saietenen betta say sce ve ten SuIyIom ‘souoydopay, [[ogq@-tamox ~ 9100-0 } 0.0899 { 6L UL oth) ; PTR. TIMOS "poosd £patez *poye[noreo 7 G ne easeg **98v09 Poese oe ys COTTON 1uH suryvedg -ouoydoyay, [fog-t0a0 ST00-0 Ay aay GIT [°7'*** wedo f 9s04q mon || eeyuag ‘PPT pur ZpT ‘son orp ond sarah i G. £962 Te [rrtttet + punoasxepug { “ess UreTUE”, pue UopuoTy ‘poos “poqe[noyeo G.Z "** partasog ] **48809 se eeee ss QUOISIOYTY pus Buryeody -ouoydopoytfog-tomoy | 1 4000-0 DERGs 06 tt ttt uedo J 9s MON || wEYUOG “PHI PUL ZpT “son ‘spuooas ur |, *so[ IU ‘soqou ormoydoay, quoaano a ee x Res ul ‘oqnoyy "Od M. jo poodg TOL TOL yyeuoy 1887.] ‘SOIL YSNOAT} JUoLING Jo poodg oy} Gurmoys 9[q%,J, [ Mar. 3, On the Mr. W. H. Preece. 156 *2-OT x Zz st toddoo xox 4uvysu0d otf fT, » ‘TY e—OT X ZE = Z B[NULOF oY} WLOAT poyefnoyeo st poods oT—'q' NT eecee **(odnes re) ‘ONT “OTA >» Kemyrey eS. “paaresqo Shz-h "petaaoyn } ..,. : UoIT) osuURTOXm yoo39 per you suoydoroy, { 00-0 \ 8-AIP9L FIO-66L |* °° uedo co ep te joodisary + 03 osueyo “XI YOo}g wopuoy ‘TT on eo Ammqsmoryg © ee oe ms e@ecve (aT qQvo Ysuy G- TLLS1 ¢-8T Pee, pue MoU 94} LOY soul; pur) *“P00S SOdI0A SI. 1g¢z |** uedo 19489010 MA 2.4 J | ULAONT 07 UOpuoT -xoddog *poatasqo omlog + ‘ouoydefay, s,1eulLTeg G00 - Ox ‘+ (]JomUByT pue ueyueg 0. T2201 68 peeeeeee sonumnoiscopuy 4 | ueaajeq dooy peuorippe Yj) Ueyaeq oO} uopuoT ee eee ee “Aqjnorgip yo yurod aq} surovordde ynq ‘poos sut -yeodg ‘ouoydoray, []eq-t9Mo04n *poye[noyeo 2600-0 "s9010A poos AoA pure poqeTnoyeo { oe be sanessdggiirmes qd =o. souoydeys} poos Axa sormbexy Z1LP00- 0 0-079eT 0g sree sstado DVETD CUS He ean | "ATF 07 9TGe PPeATesdoO 6-69 pe a EROINUO'S een ec Sec qsnf 4{uQ ~ouoyderay, 8 tourptog ZLPOO-0 } geval 1 Ge * "<<" uedO Ee { PTO MenT MON G.&Z eee ‘petaso0g : { eoeeeveecen * *sU09S1OUT VY 04 Pea etter {| 06 fitttttuedg f “MA {| uopuoy ppT pur gPT ‘son ‘UOI4BSI9AMOD WO ALIBI 0} OTQIS peyepnoyeo \ { 8 ue eer ** 48809 be ies. © * UROL AN OF -sodury -qeods 0} ofqe ysnf d[uQ |S $800.0 eTensull BLL [ttt ++ tadg f 4se4q Mont || wequeg ‘PFT pur gPT ‘son ‘yvods 04 o[qissod ysnf AjuQ { “poyepnopeo cn ec | Ym a es | re om | ee ‘spuooes ur |. “go]LUI ‘sojou ormoydoeray, quotano fnaeeee x ees Ur “oqnoy “OITA jo poodg ToL TeoL qqyouery ‘panuryjuog7—OIl \\ YSNOIg} yuotmMg Jo poedg oy} Surmoys ofqvy, 1887.] Limiting Distance of Speech by Telephone. 157 If we put equation (1) into this form, AR ae A sce oe a 1 Cem and give to A the following values :— Copper (overhead) ............ 15,000 Cables and underground........ 12,000 Tron, (ayerhedd) 9. «jo j006-esiee'y my x0 10,000 we can find the limiting distance we can speak with any wire; for oe? = A/kr. Take copper, whose constant is 15,000, and a wire whose resistance is 1” per mile, and capacity 0°0124 per mile, then— 2 _ 15000 > 00124 z = 1100, which is the limit of speaking upon such a wire. The wire used between Paris and Brussels has a resistance of 2-4 ohms and a capacity of about 0°012 microfarad per kilometre, and as that distance is only about 200 miles the speaking must be excellent. Moreover, there is reason to believe, from the difference between observation and calculation, that the static capacity on Continental and American lines is less than that of Hnglish lines, owing to the use of earth wires on all poles in Hngland, and therefore the distance would be greater. Take an Atlantic cable— , _ 12000 onapie kere ¢ = 96. Now I had found in 1878* that it was just possible to speak through 100 miles of such a cable—a very close agreement. Moreover, by the law of the squares, 100 miles of an-Atlantic cable ought to transmit 1562 reversals, if 2584 miles transmit 24, and this is probably the average number of sonorous vibrations imparted by the human voice, when hearing by telephone begins to get difficult by the loss of the higher partials and overtones. There is another interesting consequence of Thomson’s law which comes out of these experiments, and that is, whether the line bea single wire completed by the earth, or a double wire making a metallic circuit, the rate of speed between the two ends is exactly the * ©Phil. Mag.,’ April, 1878. 158 VS nik. Kipianni [Mar. 8, same, and therefore the distance we can speak through is just the same whether we use a single or double wire circuit. This is owing to the fact that though in the latter case we double the total resis- tance, we halve the total capacity, and therefore the product remains the same. The difference between copper and iron is clearly due to self- induction, or to the electromagnetic inertia of the latter, and the difference between copper overground and copper underground is due to the facility that the leakage of insulators offers to the rapid dis- charge to earth at innumerable points, of the static charge, which in gutta-percha-covered wire can find an exit only at the ends. It is also evident that there is no difficulty in working telephones through underground wires, even though they attain 50 miles in length, and in fact it would be better to work underground with proper copper wire from London to Brighton, than to use iron wires along the railway telegraph poles, owing to the > abe of external - disturbances in the former case. The limit of working of different insulated wires is easily obtained by equation (2), and the following table gives that information for different gutta- percha- -covered wires. No. | k. | T. Limit of speech. = 0-270 mf. 45°00 ohms. 32 miles. ~ 62805 23:00 ,, wes a0 ; | i aoa a 13°00 ,, ele — 7 cue 0-290 _,, 10-25 |= 64 94 N.B.—The top number indicates the gauge of wire, and the lower number that of the gutta-percha. IV. “The Etiology of Scarlet Fever.” By E. Kun, MD. F.R.S., Lecturer on General Anatomy and Physiology at the Medical School of St. Bartholomew’s Hospital, London. Received February 23, 1887. The investigation, the results of which I now record, was com- menced at the end of December, 1885. It arose out of an inquiry into the prevalence of scarlatina in different quarters of London, under- 1887. ] The Etiology of Scarlet Fever. 159 taken by the Medical Department of the Local Government Board as a part of its business of investigating local epidemics. That inquiry had demonstrated milk from a farm at Hendon as the cause of the scarlatina, and had adduced strong circumstantial evidence that the scarlatina had been distributed, not in the whole, but in certain sec- tions of the Hendon milk, and further that the ability of the sections of milk service to convey the disease had been related to a malady affecting particular cows. ‘This evidence against particular cows at the Hendon farm could not and did not aspire at furnishing direct and definite proof of the connexion of this cow disease with scarlet fever of man, for the inductive methods usually employed by the Medical Department of the Local Government Board when applied to inquiries about epidemic spread of scarlatina can for obvious reasons yield but circumstantial evidence. As on various former occasions, so also on this, the Medical Department sought to put the above conclusions to the test of scientific experiment. This task was delegated to me by the Board. The first part of this work has been published in the recently issued volume of the Reports of the Medical Officer of the Local Government Board for 1885-1886, I have therein shown that the suspected cows from the Hendon farm that had been made the object of special study, showed besides a skin disease—consisting in ulcers on the udder and teats, and in sores and scurfy patches and loss of hair in different parts of the skin—also a general disease of the viscera, notably the lungs, liver, spleen, and kidney, which resembled the disease of these organs in acute cases of human scarlatina. I have further shown that the diseased tissues of the ulcers on the teats and udder produced on inoculation into the skin of calves a similar local disease, which in its incubation and general anatomical characters proved identical with the ulceration of the cow; and further, that from the ulcers of the cow a species of micrococcus was isolated by cultivation in artificial nutritive media, which micro-organism in its mode of growth on nutritive gelatine, on Agar-Agar mixture, on blood serum, in broth, and in milk, proved | very peculiar and different from other species of micrococci hitherto examined. With such cultivation of the micrococcus I have produced by subcutaneous inoculation in calves a disease which in its cutaneous and visceral lesions (lung, liver, spleen, and kidney) bears a very close resemblance both to the disease that was observed in the Hendon cows as well as to human scarlatina. The second part of the work, carried out during 1886-1887 for the Medical Department, had for its object to investigate whether or no the disease, human scarlatina, is associated with the identical micro- coccus, and whether this, if obtainable from the human subject, is capable of producing in the bovine species the same disease as was observed in the Hendon cows and in the calves experimented upon 160 The Etiology of Scarlet Fever. , [ Mar. 3, from the latter source. The definite and clear proof that this is really the case has now been obtained, and the ewileneg I now bring to the notice of the Royal Society. On examining acute cases of human. scarlatina—for which oppor- tunity I owe great thanks to Dr. Sweeting, the Medical Superintendent of the Fulham Fever Hospital—lI soon ascertained the fact that there is present in the blood of the general circulation a species of micro- coccus, which on cultivation in nutritive gelatine, Agar-Agar mixture, blood serum, and other media, proved to be in every respect identical with that obtained from the Hendon cows. Out of eleven acute cases of scarlet fever examined in this direction, four yielded positive results: three were acute cases between the third and sixth day of illness with high fever temperature, and the fourth was a case of death from scarlatina on the sixth day. In all these four cases several drops of blood were used, after the customary methods and under the required precautions for establishing cultivations in a series of tubes con-— taining sterilised nutritive gelatine, and generally only a very small number of these tubes revealed after an incubation of several days one or two colonies of the micrococcus. This shows that the micro- cocci were present in the blood in but small numbers. Having ascertained the identity in morphological and cultural respects of the micrococeus of the blood of human scarlatina with the organism obtained from the Hendon cows, the action of the cultiva- tions of both these sets of micrococci was then tested on animals and the results compared. It was found that mice—wild mice better than tame ones—on inoculation as well as feeding, became affected in exactly the same manner, no matter whether the one set of cultivations or the other was used. The great majority of these animals died after between seven and twenty days; the post-mortem examination revealed great congestion of the lungs, amounting in some cases to consolidation of portions of the organ, congestion of the liver, congestion and swelling of the spleen, great congestion and general disease of the cortical part of the kidney. From the blood of these animals, taken directly from the heart, cultivations were established in nutritive gelatine, and hereby the existence of the same species of micrococci was revealed; they possessed all those special characters distinguishing the cultivations of the micrococcus of the Hendon cows and of the human scarlatina. In the third and concluding section of the work, cultivations of the micrococcus of two cases of human scarlatina were used for infecting calves; two calves were inoculated and two were fed from each set of cultivations. All eight animals developed disease, both cutaneous and visceral, identical to that produced in the calves that had been last year infected with the micrococcus from the Hendon cows. From the heart’s blood of calves thus infected from human al ieee Presents. 161 scarlatina the same micrococcus was recovered by cultivation, pos- sessing all the characters shown by the cultures of the micrococcus of the Hendon cows, and of the cases of human scarlatina. It must be evident from these observations that the danger of scarlatinal infection from the disease in the cow is real, and that towards the study and careful supervision of this cow disease all efforts ought to be directed in order to check the spread of scarlet fever in man. It is also obvious that in the agricultural interest alone investigations of this cow disease are greatly called for. Presents, March 3, 1887. Transactions. Baltimore :—Johns Hopkins University. Circulars. Vol. VI. No. 55. Ato. Baltimore 1887. The University. Batavia :—Bataviaasch Genootschap van Kunsten en Wetenschap- pen. Notulen. Deel XXIV. Afi. 2. 8vo. Batavia 1886; Tijd- schrift voor Indische Taal-, Land- en Volkenkunde. Deel XXXI. Afl. 2 (Vervolg) & 3. 8vo. Batavia 1886; Neder- landsch-Indisch Plakaatboek, 1602-1811. Deel III. 1678- 1709. 8vo. Batuvia 1886; De Vestiging van het Nederlandsche Gezag over de Banda-Hilanden 1599-1621. Large 8vo. Batavia 1886; Realia. Register op de Generale Resolutién van het Kasteel Batavia. 1632-1805. Deel III. 4to. Batavia 1886. The Society. Bombay :—Literary Society of Bombay. Index to the Transactions, Vols. I-III, and to the Journals, Bombay Branch, Royal Asiatic Society, Vols. I-X VII, with a Historical Sketch of the Society. 8vo. Bombay 1886. The Bombay Branch, R.A. Society. Brisbane :— Geographical Society of Australasia, Queensland Branch. Proceedings and Transactions. Vol. II, Part 1. 8vo. Brisbane 1886. The Society. Brussels:—Académie Royale des Sciences, &c. Annuaire. 1887. 12mo. Bruxelles 1887. The Academy. London :—Mineralogical Society: Mineralogical Magazine and Journal. Vol. VII. No. 33. 8vo. London 1886. The Society. Physical Society. Proceedings. Vol. VIII. Part 3. 8vo. London. 1887. The Society. Royal Institute of British Architects. Journal of Proceedings. Vol. III. No. 9. 4to. London 1887. The Institute. Society of Chemical Industry. Journal. Vol. VI. No.1. Folio. London 1887. The Society. VOL. XLII. N 162 Presents. — [Mar. 3, Transactions (continued). Marlborough :— Marlborough College Natural History oan ee. Report. No. 35. 8vo. Marlborough 1887. he College. Rome :—R. Comitato Geologico d’Italia. Bollettino. No. 11 e 12. Svo. Roma 1886. The Committee. St. Petersburg :—Académie Impériale des Sciences. Mémoires. Tome XXXIV. Nos. 7-11. 4to. St. Pétersbowrg 1886. The Academy. Comité Géologique. Bulletins. Tome V. Nos. 9-11. 8yvo. St. Pétersbourg 1886-87. The Committee. Sydney :—Linnean Society of New South Wales. Proceedings. Series II. Vol. I. Part 3. 8vo. Sydney 1886. : The Society. Royal Society of New South Wales. Journal and Proceedings. Vol. XIX. 8vo0. Sydney 1886. The Society. Turin :—R. Accademia delle Scienze. Atti. Vol. XXII. Disp. 2. 1886-7. 8vo. Torino. The Academy. Washington :—Philosophical Society. Bulletin. Vol. IX. 8vo. Washington 1887. The Society. Wiirzburg :—Physikalisch-Medicinische Gesellschaft. Sitzungs- berichte. Jahre. 1886. 8vo. Wiirzburg 1886. The Society. Observations and Reports. Albany :-—State of New York. Panini of the State Geologist. 1882-84. 8vo. and 4to. Albany 1883-85. The State Geologist. Berlin :—K6nigl. Preuss. Meteorologisches Institut. Ergebnisse der Metecrologischen Beobachtungen im Jahre 1885. 4to. Berlin 1887. The Director. Birmingham :—Free Libraries. Twenty-fifth Annual Report. 1886. 8vo. Birmingham 1887. The Committee. Calcutta :—Meteorological Observations recorded at Six Stations in India, 1886. September. Folio. [ Calcutta] 1886. The Meteorological Office, India. Cambridge, Mass.:—Harvard College Astronomical Observatory. Forty-first Annual Report. 8vo. Cambridge, Mass. 1887. The Director. Dun Echt :—Observatory. Circular. Nos. 124-139. 4to. [Sheet. ] Dun Echt 1886-87. The Earl of Crawford, F.R.S. Hongkong :—Observatory. Government Notification. No. 493. Folio. [Sheet.] Hongkong 1886. The Observatory. London :—Meteorological Office. Hourly Readings, 1884. Part 2. April to June. 4to. London 1887. The Office. 1887. . . » WPresents. 163 Observations, &c. (continued). Navy Medical Department. Statistical Report of the Health of the Navy. 1885. 8vo. London 1886. The Department. Melbourne :—Observatory. Monthly Record. August, 1886. 8vo. Melbourne. The Director. Paris:—Bureau Central Météorologique de France. Rapport du Comité Météorologique International. Réunion de Paris. 1884. Svo. Paris 1887. The Bureau. St. Petersburg :—Physikalisches Central-Observatorium. Annalen. | Jahre. 1885. Theil 1-2. 4to. St. Petersburg 1886. The Observatory. . Burdett (H. C.) Burdett’s Official Intelligence. 1887. 4to. London 1887. The Compiler. Cassagnes (G.-A.) _ La Sténo-Télégraphie. 4to. Paris 1886. The Author. Despeissis (L.-H.) La Sténo-Télégraphie. 8vo. Paris 1886. M. Cassagnes. Frost (P.), F.R.S. Hints for the Solution of Problems in the Third Hdition of ‘ Solid Geometry.’ 8vo. London 1887. The Author. Jones (J.) Medical and Surgical Memoirs. 1855-86. Vol. II. 8vo. New Orleans 1887. The Author. Klein (F.), For. Mem. R.S. Zur Theorie der allgemeinen Gleichungen sechsten und siebenten Grades. 8vo. Leipzig 1887; Zur geome- trischen Deutung des Abel’schen Theorems der hyperelliptischen Integrale. 8vo. Leipzig 1887. The Author. Loomis (H.) Contributions to Meteorology. II. 4to. New Haven 1887. The Author. Smith (R. Angus), F.R.S. Life and Works of Thomas Graham, D.C.L., F.R.S. Edited by J. J. Coleman. 8vo. Glasgow 1884. | The Editor. 164 Dr. J. Hopkinson. — [Mar. 10, March 10, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. ) The following Papers were read :— I. “Note on Induction Coils or ‘Transformers? ” By Joun Hopxinson, MA. D.Sc. F.R.S. Received February 17, 1887. The transformers considered are those having a continuous iron magnetic circuit of uniform section.* Let A be area of section of the core, m and n the number of convolutions of the primary and secondary coils respectively, R, r, and p their resistances, p being the resistance of the secondary external to the transformer, # and y currents in the two coils, a induction per square centimetre, a the magnetic force, I the length of the magnetic circuit, EK = B sin 27(t/T), the difference of potentials between the ex- tremities of the primary, T being the periodic time. We have (1.) 47(maet+ny) = la; (2.) EK = Ra—mAa; (3.) 0 = (rtp)y—nAa; from (2) and (3), * For a discussion of transformers in which there is a considerable gap in the magnetic circuit, see Ferraris, ‘ Torino, Accad. Sci. Mem.,’ vol. 37, 1885; Hopkinson,. “On the Theory of Alternate Currents,” ‘Telegr. Engin. Journ.,’ vol. 13, 1884, p. 496, 1887. ] On Induction Coils or “ Transformers.” 165 (4.) nE = nRae—m(r+p)y; substituting from (1), (5.) a{vR+m(r+p)} = n2H+ (la/4r)m(r+p) ; (6.) y{wWR+m(r+p)} = —nmE + (la/4r)nR ; (r+p)mE laR(r+p) es ere ea) | 4c a We may now advantageously make a first approximation, neglect la in comparison with 47mz, that is, assume the permeability to be very large, we have (r+p)mB sin(27#/T) | vrR+m (rtp) ’ (r+p)mB cos(2zt/T) {PR+m*(r+p)}. Qrt/T (8.) Aa = — (9.) Aa = For practical purposes these equations are really sufficient. We see firstly that the transformer transforms the potential in the ratio n/m, and adds to the external resistance of the secondary circuit p a resistance (n?R/m?)+r. This at once gives us the varia- tion of potential caused by varying the number of lamps used. The phase of the secondary current is exactly opposite to that of the primary. In designing a transformer it is particularly necessary to take note of equation (9), for the assumption is that a is limited so that la may be neglected. The greatest value of a is B/{(27/T)mA}, and this must not exceed a chosen value. We observe that B varies as the number of reversals of the primary current per unit of time. But this first approximation, though enough for practical work, gives no account of what happens when transformers are worked so that the iron is nearly saturated, or how energy is wasted in the iron core by the continual reversal of its magnetism. The amount of such waste is easily estimated from HEwing’s results when the extreme value of a is known, but it is more instructive to proceed to a second approximation, and see how the-magnetic properties of the iron affect the value and phase of x and y. We shall as a second approximation substitute in equations (5) (6) (7) values of « deduced from the value of a furnished by the first approximation in equation (9). In the accompanying diagram Oz represents «, ME represents a, and Oz the time ¢. The curves ABCD represent the relations of a@ anda HFG the induction a as a function of the time, and HIK the deduced relation between a and t. We may substitute the values of « obtained 166 Dr. J. Hopkinson. [Mar. 10, Fie. from this curve in equations (5) and (6), and so obtain the values of a and y to a higher degree of approximation. If the values of a were expressed by Fourier’s theorem in terms of the time, we should find that the action of the iron core introduced into the expression for « and y, in addition to a term in cos (2z7t/T) which would occur if a and « were proportional, terms in sin (27t/T) and terms in sines and cosines of multiples of 27t/T. It is through the term in sin (27t/T) that the loss of energy by hysteresis comes in. A particular case, in which to stay at a first approximation would be very misleading, is worthy of note. Let an attempt be made to ascertain the highest possible values of a by using upon a trans- former a very large primary current, and measuring the consequent mean square of potential in the secondary circuit by means of an electrometer, by the heating of a conductor, or other such device. The value of a will be related to the time somewhat as indicated by ABCDEFG in fig. 2; for simplicity assume it be as in fig. 3; the Fie. 2. 1887.] On the Theory of the Alternate Current Dynamo. 167 Ries ae resulting relations of potential in the secondary and the time will be indicated by the dotted line HIJKOLMNPQ. The mean square observed will be proportional to ML../LP ; but MU.UP is proportional to EL, hence the potential observed will vary inversely as ,/LP, even though the maximum induction remain constant. If then the maxi- mum induction be deduced on the assumption that the induction is a simple harmonic function of the time, results may readily be obtained vastly in excess of the truth. II. “Note on the Theory of the Alternate Current Dynamo.” By JoHN Hopxinson, M.A., D.Sc. F.R.S. Received Feb- ruary 17, 1887. According to the accepted theory of the alternate current dynamo, the equation of electric current in the armature is yy-+ Ry = periodic function of ¢, where y is a constant coefficient of self-induction. This equation is not strictly true, inasmuch as ¥ is not in general constant,* but it is a most useful approximation. My present purpose is to indicate how the values of y and of the periodic function representing the electromotive force can be calculated in a machine of given con- figuration. To fix ideas, we will suppose the machine considered to have its magnet cores arranged parallel to the axis of rotation, that the cores are of uniform section, also that the armature bobbins have iron cores, so that we regard all the lines of induction as passing either through an armature coil, or else between adjacent poles entirely outside the armature. The sketch shows a development of the machine con- sidered. The iron is supposed to be so arranged that the currents * “On the Theory of Alternating Currents,” ‘Telegr. Engin. Journ.,’ vol. 18, 1884, p. 496. 168 Dr. J. Hopkinson. _ [Mar. 10, induced therein may be neglected. We further suppose for simplicity — that the line integral of magnetic force within the armature core may be neglected. Let A, be the effective area of the space between the pole piece and armature core when the cores are in line, /, the distance from iron to iron. Let A, be the section of magnet core, /, the effective length of a pair of magnet limbs, so that 1, may be regarded as the length of the lines of force as measured from one pole face to the next. Let m be the number of convolutions in a pair of magnet limbs, and nm, the convolutions in one armature section, T, the periodic time. The time is measured from an epoch when the armature coil we shall cousider is in a symmetrical position in a field which we shall regard as positive. z and y are the currents in the magnet and armature coils, the positive direction being that which produces the positive field at time Zero. At time ¢ the armature coil considered has area Aj’, = bo +b, cos(27t/T) + by cos(4z7i/T)+ &e. in a positive field; and area A,”, = b)—b, cos(2rt/T) + by cos(4zt/T) — &e. in a negative field, where Daa by byes MAS and by—b, +bo+ ...= 0. The coefficients bp, b,, &c., are deducible by Fourier’s theorem from a drawing of the machine under consideration. 1887.| On the Theory of the Alternate Current Dynamo. 169 Let I be the total induction in the magnet core, and let at time ¢ I be distributed into I’ through A,', I” through A,” and I’” as a waste field to the neighbouring Beton The line integral of magnetic force from the pole to either adjacent pole is l'"/k, where k is a constant. We have first to determine I’, I’, I’, in terms of x and y. Take the line integral of magnetic force in three ways through the magnets, and respectively through area A,', through area A,”’, and across between the adjacent oles lof ( os + 2h = 4ama+ Anny, lof =) + ahs = 4rmxa—Arny, AA bf (Z)+5 Bt as fap i whence Pee h J , we " = = (7h as +h) (tnmne—45(2.)) = = * Aarny. When ¢, 2, and y are given, this would suffice to determine I by means of the known properties of the material of the magnets as represented by the function f. We will, however, consider two extreme cases between which other cases will lie. First.—Suppose that the intensity of induction in the magnet cores is small, so that 1,f(I/A,) may be neglected, the iron being very far from saturation. We have— eo oy may eA ye nN oe us 2 7 me coset by onset at. ja +1 (y+ 008 pr + ye \ We see that the coefficient of self-induction y in general contains terms in cos (4zt/T). Second.—In actual work it would be nearer the truth to suppose that the magnetising current # is so great that the induction I may be regarded as constant, and the quantity /,f(I/A,) as considerable. But as small changes in I imply very great changes in /,f(1/A,), its value cannot be regarded as known. We have then— 170 Capt. W. de W. Abney [Mar. 10, EOl> bres ore As) AG? ) pea a te = aie ee . Army )+4rmy, 1 2b —A, ” A), Meee seer: aig tay) — Ao whence (Pai (As (Al —A,”)? ny | 4arny Ay +A,7+2kl, | Ay’ +Ay"+ 2h, he io Gay ahs Ay fout 4A, eas + 2k, (A,’ + Ao) Anny eee are: AY EAS Oe aa For illustration, consider the simplest possible case: let b) = 6, = ZA,, and b, = bg =... = 0, and let 2k1, be negligible; we haye— V—[” = Loos + Ay sin” - : oe and the equation of current will be— ar. ant drnA, d Ry =n) isin 7 cone ata 7 instead of the simple and familiar linear equation. III. “Transmission of Sunlight through the Earth’s Atmo- sphere.” By Captain W. pe W. Apney, R.E., F.R.S: Received February 17, 1887. (Abstract. ) The observations were made by means of the colour photometer which General Festing and himself introduced last year, and which they described in the Bakerian Lecture for 1886. They extended over more than a year, the object being to ascertain the intensity of the different rays in the solar spectrum after passing through various thicknesses of the atmosphere. Owing to the unpromising results obtained by Langley with his bolometer experiments, it was not anticipated that the variation in the intensities of the different rays would obey any law, but subsequent investigation showed that as a rule the intensity of any ray obeyed the law enunciated by Lord Rayleigh, in that I’ =I«~***, where I and I’ are the initial and transmitted wave-lengths, x the thickness of the medium through which the ray passed, and k a constant, \ being the wave-length. The 1887.] Transmission of Sunlight through the Atmosphere. 171 standard illuminating value of the spectrum was taken from observa- tions made in Switzerland at 8000 feet altitude on September 15 at noon. The other observations were made at South Kensington. It was found that with the wind in the proper quarter the sky at the latter place was as pure in colour as in the country, and that measures made on the days on which there was apparently no haze gave results which when combined together gave a minimum value for & of 0:0013. A mean of the results showed that i = 0°0017. The author then discusses the value of the area of the curves so — obtained, and shows that astronomers who have used the ordinary logarithmic formula of I’ = Ia~****? have not erred in so doing, but that these results are perfectly concordant with the results obtained by taking the different values of absorption over the whole visible spectrum. He further shows that with the coefficients of trans- mission for different wave-lengths which Langley has published, the above formula is applicable,which is contrary to the theory which Langley propounded. The author further shows that when using the part of the spectrum to which various photographic salts are sensitive, the areas of the curves of intensities also fall in with the logarithmic formula. He also points out that if the value of » in the formula I’= Ie? (from which the formula I’ = Tas” is deduced) be divided by 104: in the case of the optical value, or by 255 in the case of the photo- graphic value, when bromoiodide of silver is employed on the sensitised plate, the value of & is obtained. 104 and 255 represent 1/d* of 5570 and 4450 respectively. From this he deduces the fact that the illuminating value of any part of the visible spectrum on any day at any hour can be ascertained by taking the optical and photographic values of total sunlight. This plan not only enables the light which undergoes general absorption to be calculated, but also the values of loss of intensity for each ray. He further indicates that a double photographic observation, in one of which the less refrangible end of the spectrum, and in the other of which the more refrangible is used, will give similar results. Experiments on the photographic methods are described, and the results agree with those which theory indicated would arise. The author states that the high altitudes in the Alps may not be suitable for observations of wave-lengths in the infra-red; but that they are especially suitable for observations in the visible part of the spectrum, since the atmosphere is very often free from dust, though it may not be free from aqueous vapour, and the latter affects the dark rays vastly more than it does the visible rays. He then points out the probable cause of the presence of particles which scatter ight, and briefly discusses the differences which he obtains in his value for the transmission of light, as compared with Bouguer, Seidel, 172 Presents. [Mar. 10, Pritchard, and others. He further shows that observations made by people who are colour-blind in the red tend to diminish the value of the coefficient of transmission, and that the difference between stellar and solar light cannot account for the apparent discrepancy. It would appear that Professor Pritchard’s maximum value for the coefficient of transmission at Cairo does not differ much from his. The values of the different colours in the spectrum which Rood has adopted from Vierordt’s method are then discussed, and corrected according to the author’s determination of the values on a day in June. A series of tables close the paper, in which the original observations and the deduced values are given. Presents, March 10, 1887. Transactions. Calcutta :— Asiatic Society of Bengal. Journal (Natural History). Vol. LV. Part 2. No. 3. 8vo. Calcutta 1886. Journal (Philo- logical). Vol. LV. Part 1. No.3. 8vo. Calcutta 1886; Pro- ceedings. 1886. Nos. VIII-IX. 8vo. Calcutta. _ The Society. Dublin :—Royal Irish Academy. Proceedings (Literature, &c.). Vol. II. No. 7. 8vo. Dublin 1886. Proceedings (Science). Vol. IV. No. 5. 8vo. Dublin 1886; Transactions (Literature, &e.). Vol. XXVII. Parts 6-8. 4to. Dublin 1885-86. Trans- actions (Science). Vol. XXVIII. Parts 21-25. 4to. Dublin 1885-86 ; “Cunningham Memoirs.” Nos. II-III. 4to. Dublin 1886. The Academy. - London :—Entomological Society. Transactions. 1886. Part V. 8vo. London. The Society. Odontological Society. Transactions. Vol. XVI. 8vo. London 1884. Ditto. Vol. XVII. No.1. 8vo. London 1884, The Society. Manchester :—Geological Society. Transactions. Vol. XIX. Parts 3-4, 8vo. Manchester 1887. The Society. Paris :—Société Francaise de Physique. Collection de Mémoires relatifs & la Physique. Tome III. 8vo. Paris 1887. The Society. Pesth :—KG6nigl. Ungar. Geologische Anstalt. Fo6ldtani Kozlony. Kotet XVI. Fuzet 7-12. 8vo. Budapest 1886; Mittheilungen aus dem Jahrbuche. Band VIII. Heft. 4. 8vo. Budapest 1887; Catalog der Bibliothek. Suppl. 1. 8vo. Budapest 1886. The Institution. Stockholm :—Kongl. Vetenskaps-Akademie. Ofversigt. Arg. 43. No. 10. 8vo. Stockholm 1886. The Academy. 1406 ae Presents. 173 Transactions (continued). Turin :—R. Accademia delle Scienze. Atti. Vol. XXII. Disp. 3. 1886-87. 8vo. Zorino. The Academy. Vienna:—K. Akademie der Wissenschaften. Anzeiger. 1887. Nr. I-V. 8vo. [ Wien]. The Academy. Watford :—Hertfordshire Natural History Society. Transactions. Vol. IV. Part 4. 8vo. London 1887. The Society. Airy (Sir G. B.), F.R.S. Numerical Lunar Theory. 4to. London 1886. The Astronomer Royal. Andrews (T.) Hffect of Temperature on the Strength of Railway Axles. Part II [In Manuscript]. Folio [1887]. The Author. Liihmann (O. von) Sprache und Schrift. (Two copies). 12mo. | Greifswald 1887]. The Author. Newton (A.), F.R.S., and J. W. Clark. The Woodwardian Professor and the Sedgwick Memorial Museum. 8vo. Cambridge 1887. The Authors. Sasse (H.) Die Erhaltung der Empfindungs-Energie. 8vo. Berlin 1887. The Author. Serraut (E.) L’Acide Sozolique. (Two copies). 8vo. Paris [1886]. The Author. Shaw (H. 8. Hele). Cantor Lectures on Friction. 8vo. London 1886. The Author. Stolipine (D.) Essais de Philosophie des Sciences. 8vo. Geneve 1886. The Author. Photographs of Cape Observatory, Exterior and Interior; with Photograph of Stars about 7 Argus, and other Photographic Star-maps. Dr. Gill, F.R.S. Mezzotinto Engraving of Thomas, Lord Bishop of Rochester, and Thomas Sprat, A.M., Archdeacon of Rochester. Mr. Eldridge Spratt. 174 Mr. W. Galloway. [ Mar. 17, March 17, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “A Coal-dust Explosion.” By W. GaLLoway. Communi- cated by R. H. Scort, M.A., F.R.S. Received February 17, 1887. (Abstract. ) The Silkstone pits of Altoft’s Colliery, near Normanton, in York- shire, in which the explosion took place, are 420 yards deep. Both shafts are round, the down-cast being 12 feet and the up-cast 10 feet in diameter. The thickness of the working, including a bed of soft shale below the seam, used as a holing, is 4 feet 6 inches. The system of working is longwall. The number of men and boys employed underground in the day shift was about 350. The colliery is now twenty-one years old. Very little fire-damp is produced in the workings. Naked lights were used by all the workmen for twenty years before February, 1886, yet during the whole of that period no single workman had been injured by an explosion of fire-damp, great or small. Besides being naturally very free from fire-damp, the workings of this mine were continuously swept by strong and swift currents of air, produced by means of two ventilating furnaces at the bottom of the up-cast shaft, amounting in the aggregate to 147,380 cubic feet per minute. As the roof subsides upon the stowing near the faces, it is neces- sary to take down a certain thickness of it in the stall roadways, in order to preserve them at a workable height. For this purpose about 4 feet in thickness of roof was taken down by blasting in each stall road, the height being thus made about 8 feet 6 inches, at a distance of 10 or 12 feet back from the face. Hach stall road thus required about one blasting-shot, with a charge of from two to three pounds of powder to be fired in it about once every five or six days, so that from seven to ten blasting-shots were fired near the faces every day. In this way the floor of each roadway became covered with small 1887.] | A Coal-dust Explosion. 175 pieces of broken roof, which completely obscured any small quantity of coal or coal-dust that might have fallen upon it, and been left there in the process of coal-getting. The tubs consist of rectangular wooden boxes, mounted on wooden frames, with wheels attached to them. They were filled with coal to a level with the top, and then contained about 10 cwt. Thus, although no coal could fal] over the ends or sides, the vibration due to the operation of hauling caused coal-dust and small pieces of coal to be shaken out through the seams in the sides and bottom on to the roadway beneath. Here it accumulated little by little between the rails, and to a distance of a few inches on each side of them, and the attrition due to the constant trampling of men and horses, together with the occasional dragging of the endless chains on the floor, gradually reduced it to a state of fineness. The quantity of coal-dust which accumulated on any roadway was thus, other things being equal, proportional to the number of full tubs that had passed along it from the first; so that the oldest roadways would naturally be the dustiest, were the accumulations not removed from time to time. Kach return air-way represents the continuation of a stall road all the way from near the bottom of the up-cast shaft to the face, and it must therefore contain in any given section of its length about the same average quantity of coal-dust as any ordinary stall road. But the return air-ways are all used as travelling roads for the men and boys going to and from the faces, and the constant trampling of feet soon mixes up any little coal-dust there may happen to be on the floor with the dust of the roof-stuff, and reduces the whole to an impalpable powder of a light grey colour. The following oa iPeca: thus prevailed before the explosion :— 1. An unusual immunity from fire-damp. 2. Very excellent ventilation. 3. Blasting going on at the rate of say 2000 shots a year, involving the consumption of upwards of two tons of powder in the same time, and this within the zone of subsidence where, practically speaking, all the fire-damp was given off, and where there was no coal-dust. 4, Pure air filling the intake say from the bottom of the down-cast to the faces. 5. Air containing all the fire- damp in the colliery filling the working, places and the return air-ways from the faces to the up-cast. 6. Coal-dust in the intake air-ways decreasing aly near the faces. 7. Light grey dust of roof-stone, but no visible coal-dust in | the return air-ways. The colliery had been carried on under these conditions for seven- 176 Geometrical Construction of the Cell of the Bee. [Mar. 17, teen years within the experience of the present manager. During the whole of that time no blasting had ever been done in any intake air- way. On the 2nd of October last, however, a party of men were instructed to blast away a portion of the side of the west chain road at a distance of about 550 yards from the bottom of the shaft. They fired three shots in all, and the third caused the explosion. It was not a blown-out shot in any sense. The mechanical effects were exactly the same as those produced by other explosions. Timber was torn out, and falls of roof some- times of great magnitude and extent were caused all through the intake air-ways, as far as the flame reached. In the endless chain roads the box part of each empty tub was swept away from the frame, and shattered into small pieces, not one being left whole. A spare pulley-wheel, 4 feet in diameter and weighing 15 cwt., which had been standing on its edge leaning against the side near the end of the west chain road, was carried four yards inwards towards the face, and laid flat on its side. : The flame traversed all the intake air-ways, except the new east road, and died out in some nearer to, and in others further from, the faces. It did not in any case pass into a return air-way. It did not reach the face of the workings at any point. The new east road was quite undisturbed. Two men who were working in it felt a concussion of the air, but saw no flame, and came out unscathed. This result appears to be due entirely to the circum- stance that the principal stables were ranged along the entrance to this road, and the ground having been kept constantly wet with the water used in the service of the horses, the flame was unable to pass that point for want of coal-dust to sustain it. II. “Second Note on the Geometrical Construction of the Cell of the Honey Bee (Roy. Soc. Proc., vol. 39, p. 253, and vol. 41, p. 442).”. By Professor H. Hennessy, F.R.S. Received February 21, 1887. | If from the intersections of the diagonals of the three lozenges forming the apex of the cell, perpendiculars be erected, these will meet at a point on the cell’s axis, and each of them is manifestly the radius of a sphere tangent to the three lozenges. » | Lemmeen », sec. 385, line So, 4 Wh UGS a bee IIT. “On Ellipsoidal Current Sheets.” By Horace Lamp, M.A., F.R.S., Professor of Pure Mathematics in the Owens College, Victoria University, Manchester. Received March 2, 1887, (Abstract. ) This paper treats of the induction of electric currents in an ellipsoidal sheet of conducting matter whose conductivity per unit area varies as the perpendicular from the centre on the tangent plane, or (say) ina thin shell of uniform material bounded by similar and coaxial ellipsoids. The method followed is to determine in the first instance the normal types of free currents. In any normal type the currents decay according to the law e~‘/"; the time-constant 7 may be conveniently called the ‘‘ modulus of decay,” or the “ persistency ” of the type. When the normal types and their persistencies have been found, it is an easy matter to find the currents induced by given varying electromotive forces, assuming these to be resolved by Fourier’s theorem, as regards the time, into a series of simple harmonic terms. Supposing then that we have an external magnetic system whose potential varies as e’?', we can determine a fictitious distribution of current over the shell, which shall produce the same field in the interior. If ¢ denote the current-function for that part of this distribution which is of any specified normal type, ¢ that of the induced currents of this type, it is shown that where 7 is the corresponding persistency of free currents. When pz is very great this becomes d= —4%, in accordance with a well-known principle. This method can be applied to find the currents induced ee rota- 1887. | On Ellipsoidal Current Sheets. 197 tion of the shell in a constant field, it being known from Maxwell’s ‘ Hlectricity,’ § 600, that the induced currents are the same if we suppose the conductor to be fixed, and the field to rotate in the opposite direction. When the conductor is symmetrical about the axis of rotation, the current-function of any normal type contains as a factor cos sw or sin sw, where w is the azimuth, and s is integral (or zero). When we apply Maxwell’s artifice, the corresponding time- factor is e'?!, where p is the angular velocity of the rotation; and we easily find that the system of nduced currents of any normal type is fixed in space, but is displaced relatively to the field though an angle 1 — are tan Lee s in ee in the direction of the rotation. In the most important normal types the distribution of current over the ellipsoid is one which has been indicated by Maxwell (‘ Electricity,’ § 675) as giving a uniform magnetic field throughout the interior. For instance, the axes of coordinates being along the principal axes, a, b, c, we may have agh ee Cae ah ee ae and the corresponding persistency is e arb? $0 SH esa bh De, t= (40—N) orp (2.) S dn h N= i a ec a Be where arabe | Garay P+ (@pa)? (3.) p denoting the specific resistance of the material, and ¢ the small constant ratio of the thickness of the shell to the perpendicular on the tangent plane. There is a difference of electric potential over the shell, viz., we have Mat oh Ae ek Cee Nl a vias oe) G4 | La?— Mb? where Aes (@+e)7 L, M being obtained from (3) by interchanging a and ¢, or b and «, respectively. This implies a certain distribution of electricity over the outer surface of the shell. Some special forms of the ellipsoid (e.g., a sphere, or an elliptic cylinder) are considered, and the formula (2) shown to agree with the results obtainable, in these cases, in other ways. The problem of induced currents due to simple harmonic variation 198 . Prof. H. Lamb. [Mar. 24, of a uniform field, or to rotation of the shell in a uniform and constant field, is then solved; and the results are found to agree with the general theory above sketched. In the higher normal types the current-function ¢ is a Lamé’s function, degenerating into a spherical harmonic when two of the axes of the ellipsoidal shell are equal. This case alone is further discussed in the present paper; the persistency of each normal type is found, and various particular cases are considered. Of the special forms which the conductor may assume, the most interesting is that in which the third axis (that of symmetry) is infinitesimal, so that we have practically a circular disk, whose resistance p’ per unit area varies according to the law p=pV/il—r/e}, . 2 2 where p, is the resistance at the centre, a is the radius, and r denotes the distance of any point frem the centre. In any normal type of free currents the current-function is of the form dsP,(n) ¢ $= 0. 1p bow, 2G) where: 1 get At yh 7 re aa provided n—s be edd ; in other words, the current lines are the ortho- gonal projections on the plane of the disk of the contour-lines of a zonal (s = 0) or tessaral harmonic, drawn on the surface of a con- centric sphere of radius a. The corresponding persistency is RE ors 18... te) ee " In(n+1)—s*} py * nts 24... ase 2 In the most persistent type of free currents we have n = 1, s = 0, and therefore 720 2py. = This result is of some interest, as showing that the electrical time- ecnstant for a disk of uniform resistance py must at all events be considerably less than 4°93 a/po .* * T find by methods similar to those employed by Lord Rayleigh for the approxi- mate determination of various acoustical constants, that the true value lies between melo’ and 2°26 a/p’. For a disk of copper (0 =1600 C.G.S.), whose radius is a decimetre and thickness a millimetre, the lower limit gives 0°0014 sec. For disks of other dimensions the result will vary as the radius and the thickness conjointly. I hope shortly to publish the details of the investigation on which these estimates are founded. 1887.] On Ellipsoidal Current Sheets. 199 The problem of induced currents is then discussed, and I consider more particularly the case of a circular disk, of the kind indicated, rota- ting in any constant magnetic field. In view of the physical interest attaching to the question, 1t would be interesting to have a solution for the case of a uniform disk; but in the absence of this, the solution for the more special kind of disk here considered may not be uninstructive. As in all our calculations relating to ellipsoids of ronolnton we employ elliptic coordinates; viz., seeking the origin at the centre of the disk, and the axis of z noerdhenlles to its plane, we write 2=6/(l—p*) /(C+1) cosa ) y = a/ (1p) /( +1) sin » sty tn (8) z= apt. ty) where » may range from 1 to 0, and ¢ from zero (its value at the disk) to co. The magnetic potential Q due to the field may be supposed expanded, for the space near the disk, in a series of terms of the form _— Ta ds nN ds n - ) = RA) (e+ ye) a £8 b su, i, @) where P, is the zonal harmonic, and p, a similar iegaee in which all the terms are +, instead of allernately + and — The terms for which s = 0 are symmetrical Ae the axis, and produce no currents, but only a certain superficial electrification. The density of this is calculated for the particular case n = 1, 2.e., for the case of a disk rotating in a uniform field about an axis esi to the lines of force. The only terms of the expansion (9) which produce sensible currents in a rotating disk are those tessaral solid harmonics for which n—s is odd. The induced current-function is found to be (taking, say, cos sw in (9) ) (10.) where 9 = arc tan sp7, 7 having the value (7). The most important type of induced currents is when n = 2, s = 1; in which case O x 22, * See Ferrers, ‘Spherical Harmonies,’ chap. vi. 200 Prof. J. A. Ewing and Mr. W. Low. [Mar. 24, so that the lines of force at the disk are normal to it, but the direction of the force is reversed as we cross the axis of y. The ecurrent-function relatively to axes displaced through the proper angle y in the direc- tion of rotation, varies as y/{1—r/a*}. A drawing of the current lines for this case is given. As already mentioned, they are simply the orthogonal projections of the contour lines of the tessaral harmonic of the second order. | In the next type we have n = 3, s = 2, so that O x 2(a?—y"), and the current-function, relatively to displaced axes as before, varies as ay /{1— 9/2}. IV. “ On the Magnetisation of Iron in Strong Fields.” By Pro- fessor J. A. Ewine, B.Sc., F.R.S.E., University College, Dundee, and Mr. Wiut1am Low. Communicated by Sir W. THomson, Knt., LL.D., F.R.S. Received March 2, 1887. (PLATE 2.) The behaviour of iron and steel when subjected to very strong magnetising forces is a matter of considerable practical and very great theoretical interest, especially from its bearing on the molecular theory of magnetisation, which assigns an upper limit to the intensity of magnetism that a piece of iron can acquire, and even suggests that the metal may become diamagnetic under the influence of a suffi- ciently great force. All experiments hitherto made, by magnetising iron in the field of an electric solenoid, have shown that the intensity of magnetism g, as well as the induction %, is increasing with the highest values actually given to the magnetising force 4. It is scarcely practicable, however, to produce by the direct action of a magnetising solenoid, a field whose force exceeds a few hundreds of C.G.S. units. ; To refer to a few recent experiments of this class :--In experiments by one of us* on the magnetisation of long wires, the highest value of H applied to iron was about 90, and this gave an induction % of 16,500 in a soft iron wire. In Dr. Hopkinson’s experimentsf a force * Ewing, “ Exp. Res. in Magnetism,” ‘ Phil. Trans.,’ 1885, Part II. t J. Hopkinson, ‘‘ Magnetisation of Iron,” ‘ Phil. Trans.,’ 1885, Part II, 1887.] On the Magnetisation of Iron in Strong Fields. 201 of 240 gave 19,840 for the induction in a bar of mild Whitworth steel, and 18,250 in a bar of wrought iron.* The corresponding values.of J are 1563 and 1437 respectively. Probably the highest magnetisation reached in any experiments of this class already pub- lished is that found by Mr. Shelford Bidwellf in his experiments on the tractive force between the halves of a divided ring electro-magnet. For a force 4) of 585 he gives 19,820 as the value of % (calculated from the tractive force) in a wrought-iron ring. The corresponding value of J is 1530. With cast iron, Dr. Hopkinson found (in a sample of grey iron) 10,783 for the induction produced by a force of 240. The corre- sponding value of J is 841. In the space between the pole-pieces of a strong electro-magnet we have a field of force of much greater intensity than it is practicable to produce by the direct action of the electric current. This field is not well adapted for experiments whose object is to determine with _ precision the relation of magnetisation to magnetising force, on account of the distortion which it undergoes when the piece of iron to be magnetised is introduced into it. It is, however, well suited for experiments whose object is to determine how much magnetism the metal can be forced to take up. For this purpose it is of course necessary that the cross-section of the test-piece should be much smaller than the area of the pole-piece faces. In the following experiments the electro-magnet consisted of a pair of vertical limbs 25 cm. long, with cores 5 cm. in diameter, joined at the bottom by a horizontal yoke, and furnished on the top with pole-pieces, made of soft hammered scrap iron, in the form of rect- angular blocks with plane faces, whose distance from each other could be adjusted at will. The faces were 5'25 cm. square. The magnet was wound with wire large enough to permit a current of about 27 amperes to be used fora short time. In the earliest experiments the test-piece to be magnetised was a round cylinder of soft iron, with flat ends 0°34 cm. in diameter and 1'°3cm. long. This was covered with an induction coil, consisting of a single layer of fine wire, which extended over the whole length of the piece. It was placed length- wise in the centre of the field, with the pole-pieces just touching its ends, and the field magnet was excited. The test-piece was then suddenly withdrawn, while the transient current produced in the induction coil was measured by a ballistic galvanometer connected to the induction coil by long leading wires, which were twisted together * J, and H. Hopkinson have observed an induction of 20,000 in the core of a dynamo-armature, eae a force estimated at 740 (‘ Phil. Trans.,’ 1886 (Part 1) p. 355), Ta: Bidwell, On the Lifting Power of Electro-magnets and the rts ae ofTron,” ‘ Roy, Soe. Proc,’ vol. 40, 1886, p. 486. 202 Prof. J. A. Ewing and Mr. W. Low. [Mar. 24, throughout their whole length. Very few experiments were made with test-pieces of this form, for it was found that they gave by no means an exceptionally high value for the magnetic induction. This is to be ascribed to the fact that the ends of the cylinder, which were in contact with the pole-pieces, necessarily shared that value of the induction which existed in the part of the pole-piece faces which they touched, and this comparatively low induction in and near the ends of the cylinder neutralised the much higher value in the middle portion. The induction coil, being wound from end to end of the bar, gave a mean value for the whole length. To obtain higher values, it was obviously necessary to restrict the measurement of the induction to the middle portion, where the induction was greatest; and, further, it was desirable to furnish the bar with conical or some form of spreading ends, which would present an easy path for the lines of induction to converge towards the central neck. Accordingly, test-pieces were turned of the form and dimensions of Sample A. shown in Plate 2, fig. 1, where the bobbin is sketched in place between the pole-pieces. These were wound along the whole length of the narrow central neck with an induction coil consisting of a single layer of No. 36 S.W.G. silk-covered wire. In Sample A the diameter of the iron neck was 0°923 mm., and the diameter measured to the middle of the thickness of the wire forming the induction coil was 0°9495. Hence there was but little space, outside the section of the iron, enclosed by the coil; and the small amount of magnetic induction in this non-ferrous space was allowed for by a method to be explained below. In test-pieces of the form of Sample A the loss of magnetism observed on suddenly withdrawing the piece from its place between the pole-pieces of the field magnet, is less than the whole magnetism by the small but somewhat uncertain quantity of residual magnetism which the piece retains. To avoid this source of uncertainty another form of test-piece was used, which is shown in fig. 2, Sample B. Here the bobbin has its conical ends rounded at the base to form portions of a circular cylinder, and the pole-pieces are hollowed to correspond. The bobbin can now be turned completely round about a central axis at right angles to the paper, so that the direction of its magnetism is reversed, and half the ballistic effect of the reversal measures the magnetic induction. This method was used in the greater number of the observations. Again, by merely withdrawing the bobbin from the field, and comparing the effect of this withdrawal with half the effect of reversal, an estimate was arrived at of the amount of error to which the former experiments were subject on account of residual magnetism. To determine the intensity of the magnetic field in the space immediately surrounding the narrow neck in which the greatest 1887.] On the Magnetisation of Iron in Strong Fields. 203 induction occurred, a small quantity of wire was wound over the first induction coil, to form a distance-piece, and on the top of that a second induction coil was wound, the second coil, like the first, con- sisting of a single layer of very fine wire. The space between the two coils was accurately determined. When the test-piece was reversed or drawn out of the field the operation was in each case performed several times, and two groups of observations were recorded, one giving the induction in the inner coil, and the other the induction in the outer coil; the difference of course served to determine the field in the space between the coils. When this field was known it was easy to correct for the induction in the non-ferrous space enclosed by the inner coil. Three kinds of wrought iron were tested; soft hammered scrap, Swedish iron, and Lowmoor iron. The hammered scrap proved less susceptible than the other two, and was not used in the final experi- ments, which were made with test-pieces of the form of Sample B. Pieces of cast iron were also tested, in forms resembling both A and B. To determine in absolute measure the value of the ballistic effects, a large earth-coil was kept in cireuit with the induction coil and galvanometer, and was turned over in either the vertical or horizontal earth-field at the beginning, and again at the end of each group of observations. To avoid the possibility of error in this important particular, two separate earth-coils of entirely different dimensions were employed, and the galvanometer constant was determined inde- pendently by means of both, with results which were in excellent agreement. The values of the induction stated below are worked out on the basis that the horizontal force in the grounds of University College, Dundee, at a place sufficiently removed from local magnetic influence, is 0°160 in C.G.S. units. The following experiments are representative of a considerably larger number :— Lowmoor iron, annealed before turning the bobbin from a forged bar. Sample B, of shape and dimensions shown in fig. 2. Diameter of iron neck = 0°65 em.; length = 0°-44.cm. Diameter to middle of inner induction coil, 0°6765cm. Diameter to middle of outer induction coil, 0°9364 cm. Area of section of iron (S,) = 0°3318 sq. em. Area of space to be corrected for under inner induction coil (S,) = 0°0276 sq. cm. Area of space between inner and outer coil (S;) = 0°3293 sq. cm. Number of turns on inner induction coil = 16; number on outer coil = 12. In the following table D, is the throw of the ballistic galvanometer given by the inner coil when the test-piece was turned round, and D, is the throw given by the outer coil. X, and X, are the corre- 204 Prof. J. A. Ewing and Mr. W. Low. [ Mar. 24, sponding total inductions in C.G.S. units. The difference of these, given in the fifth column, when divided by Ss, is the intensity of field or magnetic force per sq. cm., in the space immediately surrounding the iron. This is given incolumn VI. Multiplying it by 8, we have the correction to be subtracted. from X,, which is given in column VII. Finally, by dividing the corrected value of X, by the section of the iron §,, we find 8, the magnetic induction in the iron per sq. cm. Column IX gives the current in the field magnet coils in ampéres. Lowmoor Wrought Iron: Sample B. I. II. III. IV. Vv. VI. VII. Vi.) (CTS Henk ered ee in field iron neck| be sub- D,. X,. D,. X,. | Xo—X). erieq, | cee h. pee em. | from X. aan 127 | 8,295|109| 9,490] 1195 | 3,630 100 | 24,700 | 1°98 143 | 9,340 | 1824] 11,540 | 2200 | 6,680 | 180 | 27,610! 4°04 150 | 9,800 | 142; 12,370 | 2570 | 47,800 220 | 28,870| 5-81 153 9,990 | 148 | 12,890 | 2900 | 8810 250 | 29,350! 7:60 1573 | 10,280 | 154 | 13,410 | 3130 | 9,500 260 | 30,200} 11:0 ~ 160 | 10,450 | 157 | 13,670 | 3220 | 9,780 270 | 30,680 | 13°5 161 | 10,520 | 160 | 13,930 | 3410 | 10,360 290 | 30,830 | 16:2 164 | 10,710 | 164 | 14,280 | 3570 | 10,840 300 | 31,370 | 21°6 6°8 165 | 10,780 | 166 | 14,460 | 3680 | 11,180 | 310 | 31,560 | 2 In another test of Lowmoor iron, conducted in the same way, a still higher value of #8 was reached, namely, 32,880. This is the highest induction that has been recorded in. these experiments. A similar experiment with a piece of Swedish wrought iron, of the form and dimensions shown in fig. 2, gave 32,310 for the greatest value of %, the magnetic force in the ring of space surrounding the iron neck being then 11,250. The amount of residual magnetism retained by a Lowmoor sample of this form (Sample B) was determined by comparing the effect of withdrawing the test-piece with the effect of reversing it. The results showed that within the range of magnetic force used in these experi- ments, namely, from about 4000 to 11,000 C.G.S. units, the residual magnetism is nearly constant. Its mean value in a number of determinations was— For Lowmoor iron, residual induction, %, = 510 per sq. em, For Swedish iron, residual induction, %, = 500 per sq. em. These results showed that pieces of the form of Sample B (fig. 2) retained only a small part (less than 1/60) of their greatest induction when withdrawn from the field. The proportion of residual, to 1887.] On the Magnetisation of Iron in Strong Fields. 205 greatest induced magnetism in samples of the form A (fig. 1), is probably not very different from this. In the following experiment a bobbin of annealed Swedish iron, of the size and shape shown in fig. 2, was tested by withdrawing it from the field. The columns of the table have the same meaning as before, except that the quantity in column VIII, now headed % — %,, is not the whole induction per sq. cm., but that part of the induction which disappeared when the test-piece was withdrawn from the field. In this case the section of the iron was the same as before, but the space between the inner and outer induction coils (S;) was 0°308 sq. cm. There were fourteen turns in the inner coil and twelve in the outer. Swedish Wrought Iron: Sample B. 1 II, III. IV. V. VI. VII. VIII. IX. : - Field | Correc- round | tion to ae D D x Xoo K iron | besub- | a im ne 1: X). 2° 2° 1: neck per tracted 4% an B. magnets, . amperes. sq. cm. | from X). ee 125°5| 9,290 |131°5| 11,350 | 2060 6,690 180 27,460 | 4:08 134°5| 9,950 |147°0| 12,690 | 2740 8,900 250 29,230 | 7°77 139°5 | 10,320 |153°5} 13,250 | 2930 9,510 260 30,320 | 10°9 1415} 10,470 |157°0] 13,550 | 3080 | 10,000 280 30,710 | 14°2 143°5 | 10,620 |}160°0/ 13,810 | 3190 | 10,3860 290 31,130 | 16°5 144°0} 10,660 |162°0| 18,990 | 33830 | 10,810 300 31,220 | 18°9 145°5| 10,770 |163°5} 14,120 | 38350 | 10,880 300 31,560 | 22°9 147-0} 10,880 |166°0] 14,330 | 3450 | 11,200 310 31,860 | 26°5 The residual magnetism may be corrected for by adding 500 as the value of %, to each of the numbers in column VIII. We then obtain for the highest induction ¥ the value 32,360. The following results relate to test- nan of the form and size shown in fig. 1 :— Swedish wrought iron. Form of Sample A. Section of iron neck = 0°669 sq. cm. Section to middle of induction coil = 0:708 sq. cm. Loss of induction per sq. cm. tested on withdrawing the bobbin - (B—B,). Current in field magnets, . 8 — 3, amperes. 3-92 27,000 7-48 29,420 11:3 30,240 140 30,460 17-9 30,960 20°1 31,180 20 4 31,290 206 Prof. J. A. Ewing and Mr. W. Low. [ Mar. 24, These figures agree very well with those in the preceding table, which related to another sample of different form cut from the same bar. Probably 500 is in this case also a fair estimate of the residual induction, and by adding that to the values given ubove we arrive at probable values of #. Lowmoor wrought iron. Form of Sample A. Dimensions as above. Current in field magnets = 20°4 amperes. Loss of induction on withdrawing the bobbin (#— #,) = 31,660. Allowing for the residual magnetism, this gives an induction exceeding 32,000. Soft Hammered Scrap. Form of Sample A. Dimensions as above. Current in field magnets, B — By. 20°4 31,230 26-2 | 31,520 The remaining experiments relate to cast iron. The following results are for a sample of the form shown in fig. 2, except that the neck was of considerably larger diameter, namely 0°962 cm. The sample was tested by turning it end for end in the magnetic field. Section of neck = 0°727 sq. cm. Section within middle of inner induction coil = 0:°767 sq. cm. Space to be corrected for = 0:040 sq. cm. Section within middle of outer induction coil = 1:195 sq. cm. Space between coils = 0°328 sq. cm. Cast Iron. Field round | Correction ae x. A |X gif as subtracted 8. magnets, eee Cay. fo toma oS ampéres. 14,450 | 15,730 | 1280 3,900 160 19,660 1:97 16,200 | 18,300 2100 6,400 26U0 21,930 - Oia 16,910 | 19,440 | 2530 7,710 310 22,830 5 38 17,420 | 20,070 | 2650 8,080 320 23,520 7-08 18,240 | 21,260 3020 9,210 370 24,580 13°15 18,490 | 21,670 3180 9,700 390 24,900 16 °9 19,030 | 22,510] 3480 | 10,610 420 25,600 | 22°6 Another set of readings were taken with this sample at the same time, by drawing it suddenly out of the field, in order to determine the residual induction. The results showed that throughout the range of magnetic forces employed here, the residual induction had a nearly constant value of 400 C.G.S. units per sq. em. A bobbin of cast iron of a form resembling Sample A, fig. 1, was 1887.] On the Magnetisation of Iron in Strong Fields. 207 also tested by drawing it out of the field. The results were in close agreement with those given above for the other sample. In fig. 3 the general results for Lowmoor wrought iron (Sample B) and cast iron are shown by curves which give the relation (1) of the induction % within the metal neck to the current in the field magnet coils, and (2) of the induction or magnetic force in the space im- mediately surrounding the neck to the current in the field magnet coils. ‘The full lines are for the Lowmoor forging, and the broken lines are for cast iron. ‘The field produced by a given current is (at its higher values) rather less strong in the case of cast iron, probably because the larger size of the cast iron neck allowed a greater portion of the whole induction from pole to pole to find its way through the metal. (Compare X, for cast iron and for Lowmoor.) The magnetic force within the metal (%) differs from the field in the surrounding space by an amount which cannot be estimated without a knowledge of the distribution of free magnetism on the pole-pieces and conical faces of the bobbin. It appears probable that with the dimensions of the various parts used in these experiments, the magnetic force within the metal is less, but not very greatly less, than the outside and closely neighbouring field. In the absence of any exact knowledge of 4}, it is interesting to examine the relation of 4% to the outside field. Thus, (%—outside field)/4a gives a quantity which is probably not much less than the intensity of magnetism J. The values of this quantity for Lowmoor wrought iron, Swedish wrought iron, and cast iron are stated below. In the case of the Swedish iron the values of %—%, given in the previous table for that metal have had 500 added to allow for the residual magnetism. Again, the quantity #/outside field is probably not much less than the magnetic permeability w: its values also are given below. I. Lowmoor Wrought Iron. me # — outside field ® Outside field. 8. Arr. outside field. 3,630 24,700 _ 1680 6°80 6,680 27,610 1670 4-13 7,800 28,870 1680 8°70 8,810 29,350 1630 3°38 9,500 30,200 1650 3°18 9,780 30,680 1660 3°14 10,360 30,830 1630 2°98 10,840 31,370 1630 2°89 11,180 31,560 1620 2°82 208 Prof, J. A. Ewing and Mr. W. Low. ~ [Mar, 24, Ti. Swedish Wrought Iron. : % — outside field B Outside field. a. Ar. outside field. 6,690 27,960 1700 4°18 8,900 29,730 1660 3°34 9.510 30,820 1700 3°24. 10,000 31,210 1690 3°12 10,360 31,630 1700 3°05 10,810 31,720 1670 2°94. 10,880 32,060 1690 2°95 11,200 32,360 1690 2°90 III. Cast Iron. ; ® —outside field. ¥ Outside field. 8. A: outside Bela: 3,900 19,660 1250 5-04 6,400 21.930 1240 3-42 7.710 22830 1200 2°96 8,080 23,520 1230 2°91 9.210 24,580 1220 2-67 9,700 24,900 1210 2°57 10,610 25,600 1190 2-46 Fig. 4 shows by curves the relation of 4 to #/outside field for Low- moor iron and for cast iron, in the manner introduced by Rowland for showing the relation of § tow. The curves have the same kind of inflection that a curve of » and #% begins to have when the mag- netising force is raised sufficiently high.* The range through which the permeability of iron may vary is well shown by comparing the values reached here (probably in the extreme case less than 3) with the value 20,000, which was found by one of us in the case of a soft wire exposed to a very small magnetising force and kept at the same time in a state of mechanical vibration.t The quantity (3% —outside field) /47 is nearly constant in the Swedish iron, but diminishes with increased induction in the Lowmoor iron and in the cast iron. If the outside field were an accurate measure of * This feature of the curve of « and % was not noticed by Rowland himself, who applied to his curve an empirical formula which fails to take account of it. It has, however, been noticed by several later observers (Fromme, ‘ Wiedemann, Annalen,’ vol. 13, p. 695; Ewing, loc. cit., p. 574; Bidwell, loc. cit., p. 495). + Ewing, loc. cit., p. 567. ae ee 1887.] On the Magnetisation of Iron in Strong Fields. 209 4§, this would mean that in the two metals last named g had passed a maximum, and the process of diamagnetisation which the Ampére- Weber molecular theory of magnetism anticipates had set in. But the uncertainty which attaches to the value of 4) prevents this conclusion from being fairly drawn from these experiments. A slight excess in the mean value of 4) within the metal neck over the value of 4 in the space contiguous to the neck would suffice to convert the apparent decrease of g into an increase, with increasing valuesof %. So faras these results can be said to bear upon the point in question, they rather support the idea that the intensity of magnetism g becomes and remains a sensibly constant quantity when the magnetising force is raised to very high values. This maximum of g appears to exceed 1700 in wrought iron and 1250 in cast iron, and it does not appear likely that any increase of magnetising force will bring the intensity of magnetism in cast iron to a value equal or nearly equal to that which wrought iron is capable of acquiring. It is scarcely necessary to add that our experiments give no support to the suggestion that there is a maximum of the induction %. The value of ® capable of being reached by the method we have employed depends mainly on the scale of the experiments. Larger field magnets with pole-pieces tapering to a narrow neck should yield values of # greatly in excess even of those we have observed. The experiments will be continued and various qualities of steel will be examined with the following modification in the apparatus :—The pole-pieces will themselves be turned, at the ends which face each other, into cones with flat ends, between which the test-piece in the form of a round cylinder will be inserted. The induction will be measured in the neighbourhood of a medial transverse plane only, and the value of the field outside the iron will be determined in this plane at various distances from the axis. Since there is no free magnetism in the iron bar in the medial plane, the magnetic force within the metal is continuous with the force in the surrounding space, and a curve showiny the relation of the magnetic force at various points outside to the distance from the axis should admit of being produced so as to give a good approximation to the magnetic force within the metal. If this can be successfully accomplished, the value of the isthmus method of examining the magnetisation of iron will be greatly enhanced. | Dr. Hopkinson informs me that he experimented by what we have called the “isthmus” method nearly three years ago, but gave it up from uncertainty about the induction which took place through the coil but not through the iron. In the present experiments this diffi- culty has been avoided mainly by using larger bobbins with a single layer of fine wire for induction coil. I am indebted to Dr. Hopkin- son for the suggestion (soon to be put in practice) that the “isthmus” VOL. XLII. Q 210 Presents. . [Mar. 24, method should be applied to the manganese steel whose non-mag- netic quality under ordinary conditions has been already commented on by himself as well as by Mr. J. T. Bottomley and Professor Barrett. In connexion with the values of # reached by other observers, Professor J. J. Thomson informs me that in some recent experiments by himself and Mr. H. F. Newall on the effect of cutting a magnet at right angles to the lines of force, an induction of 28,000 was found on one occasion.—J. A. H.] Presents, March 24, 1887. Transactions. London :—Hast India Association. Journal. Vol. XIX. No. 2. 8vo. London 1887. The Association. Tron and Steel Institute. Journal. 1886. 8vo. London [1887]. The Institute. Munich:—Kénigl. Bayer. Akademie der Wissenschaften. Sitz- ungsberichte (Philos.-Philol. Classe). 1886. Heft 3. 8vo. Munchen. The Academy. Newcastle-upon-Tyne :—Tyneside Naturalists’ Fieid Club. Trans- actions. Vol. VIII. Part (2. 8vo. London 1886. The Club. New Haven :—Connecticut Academy of Arts and Sciences. Trans- actions. Vol. VII. Part 1. 8vo. New Haven 1886. The Academy. New York:—American Geographical Society. Bulletin. 1885. Nos. 4-5. 8vo. New York. The Society. Paris:—Ecole Normale Supérieure. Annales. Année 1887. No. 2. Ato. Paris. The School. Pisa:—Societa Toscana di Scienze Naturali. Atti. Vol. VIII. Fase. 1. 8vo. Pisa 1886; Processi Verbali. Vol. V. Novembre 1886—Gennaio 1887. 8vo. [Pisa.] The Society. Santiago :—Deutscher Wissenschaftlicher Verein. Verhandlungen. Heft 3. 8vo. Valparaiso 1886. The Union. Observations and Reports. Calcutta :—Geological Survey of India. Records. Vol. XX. 8yvo. [ Calcutta] 1887. The Survey. Meteorological Observations recorded at Six Stations in India, 1886. October. Folio. [Calcutta] 1886. The Meteorological Office, India. Helsingfors :—Institut Météorologique Central de la Société des Sciences de Finlande. Observations. 1882-3. Vol. I. Livr. 1. Vol. II. Livr. 1. Folio. Helsingfors 1886. The Society. Ewoung & Low. SAM Pig 1" POSITION. iB, ‘ -ee eee . SVNPEMLE OTN 12S ar Te) Ne Ke 14000) 12000) _| IN |THE [METAL os eae) 10000 6000 Current uv Friel Magnet Coils Amperes. 1a 4s @ r) 3+ Oudside Ii'telal 00006 00061 0006¢|— 00008 001} o0er; Weet, Newnan &O?lith 1887. | Presents. 211 Observations, &c. (continued). Hongkong :—Observatory. Government Notification. No. 38. Folio (Sheet). Hongkong 1887. The Observatory. London :—Meteorological Office. Weekly Weather Report (with Summaries). Vol. III. No. 53. Vol. IV. Nos. 1-6. 4to. London 1887; Monthly Weather Report. No. 68. 4to. London 1887; Quarterly Weather Report, April-June, 1878. Ato. London 1887; Report of the Meteorological Council to the Royal Society, 1886. 8vo. London 1887; Report of the Third Meeting of the International Meteorological Committee held at Paris, September, 1885. 8vo. London 1887. The Office. Milan :—R. Osservatorio Astronomico di Brera. Osservazioni. 1886. 4to. Milano [1887]. The Observatory. Journals. Archives Néerlandaises des Sciences Exactes et Naturelles. Tome XXI. Livr. 2-3. 8vo. Harlem 1887. Société Hollandaise des Sciences. Horological Journal (The) Vol. XXIX. No. 343. 8vo. London 1887. The Horological Institute. Indian Antiquary (The) Vol. XVI. Part 192. 4to. Bombay 1887. The Hditors. Industria (L’): Revista Tecnica ed Economica Illustrata. Vol. I. Nos. 1-ll. 4to. Milano 1887. The Publishing Committee. Industries. Vol. II. Nos. 28-37. 4tc. London 1887. The Editor. Naturalist (The) No. 140. 8vo. London 1887. The Editors. New York Medical Journal (The) Vol. XLV. Nos. 6-10. 8vo. New York 1887. The Editor. Practical Engineer (The) Vol. I. Nos. 1-2. Munchester 1887. The Publishers. Scientific News. Vol. I. No. 1. 4to. London 1887. The Editor. 212 Dr. C. R. A. Wright and Mr. C. Thompson. [Mar, 31, March 31, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “Note on the Development of Voltaic Electricity by Atmo- spheric Oxidation.” By C. R. ALpER Wricut, D.Sc., F.R.S., Lecturer on Chemistry and Physics, and C., THompson, F.C.8., Demonstrator of Chemistry, in St. Mary’s Hospital Medical School. Received March 10, 1887. Tt is well known that when metallic copper is brought into contact simultaneously with atmospheric air and aqueous solution of ammonia, rapid oxidation is set up, the copper oxide formed dissolving in the liquid, producing a blue solution of ammoniacal cupric oxide, or cuprammonium hydroxide. Whilst investigating processes for the manufacture of this fluid (now.used commercially on a considerable scale) we noticed that if the air supply be greatly in deficiency relatively to the bulk of the copper, under certain conditions the solution is but little coloured, containing copper dissolved principally as cuprous, and not as cupric, oxide. This might, perhaps, be antici- pated @ priori, inasmuch as it is well known that blue cupric solution in ammonia, when digested with metallic copper in the absence of air, takes up a second equivalent of copper, becoming colourless cuprous solution ; but further experiments seem to indicate that the production of cuprous oxide under the oxidising influence of a limited supply of air is the primary action, and not merely a secondary result ; in short, that the first step in the change is expressed by the reaction— cuprous oxide being formed, which then (under favyourakle conditions) becomes further oxidised to cupric oxide, thus— 2Cu,0+ 0, = 4Cu0, and not by the reaction— 2Cu+O, = 2Cu0; 1887.] Voltaic Electricity by Atmospheric Oxidation. 213 the cupric oxide thus formed as the first product becoming subse- quently reduced (in the absence of air) to cuprous oxide, thus— Cu0--Cu = Ca,0. When a sheet of copper is kept out of direct contact with air by being immersed in ammonia solution, oxidation of the metal is gradually effected by virtue of the dissolving of oxygen from the air at the surface of the fluid, and diffusion of the oxygen solution to the vicinity of the copper. This action is an extremely slow one if the copper be covered by some depth of fluid, and if the setting up of con- vection currents through heating or evaporation be prevented by keeping the vessel perfectly at rest and at an equable temperature, and well closed to prevent escape of ammonia; but if these precautions be neglected it goes on much more ‘rapidly, and the liquid compara- tively soon becomes blue; it can, however, be also materially acce- lerated by arranging horizontally on the surface of the fluid a plate of platinum or other electrically conducting material not chemically acted upon by the fluid, and connecting this by means of a wire, &c., with the copper plate. The upper conductor, or aération plateas it may be con- veniently termed, being simultaneously in contact with the atmosphere and fluid, attracts to its surface a film or aura of condensed gases, the oxygen of which becomes gradually transferred to the copper, a voltaic current circulating through the fluid and connecting wire. Cuprous, and not cupric, oxide thus results, dissolved in the ammonia solution in contact with the copper plate, the mechanism of the reaction being conveniently represented by the scheme— Copper plate Cu, | OH,|OH,|O Aération plate, Copper plate | Cu,0 | H,O| H,O| Aération plate, water being represented as the electrolyte for simplicity’s sake. The air film on the aération plate being constantly renewed by absorption from the atmosphere, the process goes on continuously as long as the two plates are connected together by the wire. This wire may be lengthened at will so as to make the current which passes through it whilst the action goes on relatively stronger or weaker according to the amount of resistance introduced into the circuit; and by includ- ing a galvanometer or silver voltameter in the circuit the ordinary phenomena due to the passage of currents are readily recognisable. A voltaic cell thus produced “runs down” very rapidly when the resistance in circuit is diminished, more or less recovering when the resistauce is again increased ; with a large resistance (e.g., sufficient to reduce the current density to a micro-ampére or less per square centimetre of aération plate surface), a very notable H.M.F. is main- 214 Dr. C. R. A. Wright and Mr. C. Thompson. [Mar. 31, tained, amounting under favourable conditions to 0°5 or 0°6 volt. The maximum E.M.F. thus capable of development varies considerably with the strength of the ammoniacal solution, being the less the weaker the fluid; addition of common salt or of sal-ammoniac to the liquid notably increases the H.M.F. and diminishes the internal resist- ance of the cell. Spongy platinum in a thin layer as the aération — plate gives higher values than thin platinum foil; the highest num- bers thus obtained, using pretty concentrated ammoniacal brine, fell but little short of 0°8 volt; or somewhat less than the H.M.F. corre- sponding with the heat of formation of cuprous oxide,* since, accord-- ing Julius Thomsen, Cu,,0 = 40810 = about 0°88 volt. It is obvious that this copper atmospheric oxidation cell has a close - connexion with the “air-battery’’ described in 1873 by Gladstone and Tribe (‘Roy. Soc. Proc.,’ vol. 21, p. 247) in which whatis virtually an “‘aération plate,” consisting of a tray full of crystals of silver is used, opposed to a copper plate immersed in a solution of copper nitrate. Cuprous oxide is formed in both cases, in virtue of the indirect combination brought about between the oxygen of the air and the copper: but there is this great difference between the two (apart from the cuprous oxide being deposited as such in Gladstone: and Tribe’s arrangement, and being kept in solution in ours), that in the one the cuprous oxide is formed at the surface of the copper plate itself, and in the other at the surface of the aération plate. This. essential difference is embodied in the above depicted scheme as compared with the following one which represents the action in Gladstone and Tribe’s cell :— Cu (NOsz)o | Cu Cu(NO3). [ Silver+0 Cu(NO,), | cat Copper. 0 Cu | (NO;),Cu | (NO;),Cu | i \ oes Cu | (NO,),Cu | (NO,)oCu Copper. One result of this difference is that the surface of the aération plate in the ammonia cell is kept constantly the same, whereas in the nitrate cell it is continually changing its character through deposition of solid cuprous oxide on the silver: in consequence of this deposition, whilst the E.M.F. of the ammonia cell, ceteris paribus, is constant, that of the nitrate cell is continually varying. Gladstone and Tribe, moreover, only obtained an H.M.F. of <8 to 34 of a Daniell, or about, 0°104 to 0°148 volt, even under the most favourable conditions, viz., when the cell was connected with an electrometer; whilst four or five times this amount is indicated by the cells examined by us. * The actual chemical change going on in the cell is the synthesis of cuproso- ammonium hydroxide, so that the (unknown) heat of solution of cuprous oxide in ammonia should be added to this to obtain the total heat development. 1887.] UMMMMMM@q@qe#YYMMMlib bt = Na: In order to examine separately the fluids collecting round the two plates after action had gone on for some time, we employed cells of U-shape ; and to obtain as large an aération surface as possible, we adapted to one leg of the LU a funnel (as indicated in the figure) with the stem cut off, and united to the \J-tube by a piece of india- rubber tubing, a, slipped tightly over the junction. The other end of the J-tube was closed with an india-rubber cork, b, through which passed a piece of glass tubing with a platinum wire, c, sealed into it at the lower end and filled with mercury, thus forming a mercury cup, and serving to make contact with the copper plate, d, which was soldered to the end of the platinum wire, the soidering and platinum being coated with gutta-percha, so that only the copper plate was in contact with the fluid with which the J-tube was subsequently filled. A similar glass tube and platinum wire mercury cup, f, served to make contact with the aération plate, which was conveniently sup- ported horizontally at the surface of the fluid in the funnel by means of a disk of porous earthenware, e; by fixing a rim of gutta-percha round this disk so as to convert it into a sort of tray lixe the lid of a pill-box, and filling this tray with platinum sponge, an aération plate of spongy metal was readily obtained. By interposing suitable re- sistances, galvanometer, silver voltameter, &c., in the external circuit 216 Prof. G. F. Fitzgerald. Clausius’s Formula [Mar. 31, obtained on connecting the two mercury cups by a wire, the current passing could be modified at will, and shown to exhibit all the ordinary phenomena of moderately weak currents. After continued action with small resistance only in circuit, the liquid in the funnel was found on analysis to contain no copper what- ever, whilst that surrounding the copper plate, though colourless before removal from the tube, speedily became blue on exposure to air, and contained more or less considerable amounts of copper in solution, obviously originally in the condition of cuprous oxide, Cu,O. Following up the ideas suggested by the above observations, we are making a number of experiments with a variety of analogous com- binations, in which atmospheric oxidation constitutes the essential chemical action taking place; by varying the nature of the aération plates, the metals dissolved, and the liquids employed (as also by substituting other gases, e.g., chlorine, for air), a large number of combinations are obviously obtainable. Some of those which we have so far examined present points of considerable interest, the oxidising action exerted under favourable conditions being strongly marked, so much so that certain metals, e.g., mercury and silver, not ordinarily prone to atmospheric oxidation, can under suitable condi- tions be gradually oxidised and dissolved in appropriate liquids, just as the copper is dissolved in the ammonia in the cell above described ; these actions, moreover, being accompanied by the development of currents of strength sufficient to cause measureable amounts of electro- lytic decomposition outside the cell, e.g., in a silver voltameter. II. “Clausius’s Formula for the Change of State from Liquid to Gas applied to Messrs. Ramsay and Young’s Observations on Alcohol.” By Gro. Fras. Firzcrraup, M.A., F.T.C.D., F.R.S., Erasmus Smith’s Professor of Natural and Experi- mental Philosophy in the University of Dublin. Received March 14, 1887. Clausius, in Wiedemann’s ‘Annalen,’ vol. 14, 1881, pp. 279—290, and ‘Phil. Mag.,’ vol. 12, 1881, p. 381, and vol. 13, 1382, p. 132, has given an empirical formula for calculating the relation between the volume, pressure, and temperature of a substance in both liquid and gaseous states. The equation he gives is a continuous one for an isothermal, and he determines the pressure at which evaporation takes place by considering that the work done in the transformation from liquid to gas at a constant pressure must be equal to what would be done if the transformation took place along the continuous isothermal. He requires, for convenience in applying this to actual cases, to calcu- 1887.] for the Change of State from Liquid to Gas. 217 late the values of certain rather complicated exponential functions, and has published tables of their values which greatly facilitate the work of comparing his formula with observations of vapour-pressures at different temperatures. He has compared his formula with deter- minations of vapour-pressure, &c., by Andrews and Regnault of carbon dioxide, and by Regnault and Sajotschewsky of ether, and with Reenault’s experiments on water, and has shown that they agree very well. He has also, by help of his formula, calculated the critical temperature for water, and finds it to be about 332° C., and the critical pressure to be 134 atmospheres. Professor Ramsay has kindly furnished me with his and Mr. Young’s observations on alcohol, and I have compared them with Clausius’s formula, with which they agree very well. The formula Clausius has given may be described as follows :— The relation connecting the volume, pressure, and temperature of a substance can be expressed by the formula— Oe eet ] Rn gan OE By. In this R, a, and £P are constants for each substance, p is the pressure, v the specific volume, T the absolute temperature, and 0 is a function of the temperature which vanishes with T, and for which Clausius has given the formula— *9, Ne nN a (1+0)() — 4, in which 0} and ~ are constants for any one substance, and T, and ©, the values of T and © at the critical temperature. — _ From a consideration of the isothermals represented by Clausius’s formula it is easy to show that the critical isothermal, for which two of the tangents parallel to the axis from which pressures are measured coincide, gives— | 8 Tass) As the combination xz + @ occurs frequently, Clausius denotes it by y. He expresses the specific volumes of the saturated liquid and gas by o and s, and uses wand W for o — a and s — a respectively. He also uses the symbol If = P/(RT) where P is the saturated vapour-pressure, and subscribes c, thus II-, to express the value of any of these quantities at the critical point. Hence we get— * There is a misprint of = for a on the last line of the text, formula 7, of c ‘p. 135 of Clausius’s second paper in the ‘ Phil. Mag.,’ vol. 13, 218 Prof. G. F. Fitzgerald. Clausius’s Formula [Mar. 31, pe NG = Sa —— ae Sy Aga: I have assumed as the result of observation that T, = 516°5 and P, = 49,000 mm. This latter value is probably a little too large, but, as there seems some uncertainty as to its value from the experiments, from which it is very difficult to approximate accurately to the actual position of the critical point, I have thought this value sufficiently accurate. I have calculated the result of making changes in this value, and any variation within limits allowable by the experiments does not materially affect my results. The values of these constants for alcohol as determined from the observations are— ie t= 185435 L.. = 016°5 Py = 492000 atp=y = 1°780 W, = w= ay = 3°560 ii, = _ = 0°07023 8 a2 2 ona 01664 i — 0:9118 Ye 1°3462 I have found that constant values for « and 6 do not satisfy the observations accurately, and that a varies from 1:087 at 0° C. to 0°184 at 240° C., as I explain further on. I calculated b and nm soas to make the saturated vapour-tensions correct at 0° C. and 100° C. The process of calculation I adopted was to calculate II/N, at 0° C. and 100° C., and then from Clausius’s tables obtain the corresponding values of 6/0,. This gave two equations, to determine 6 and u by means of 0,/6 = (1 + 0)(T./T)* — b. The equation for n being— This was solved by trial and error and then 6 calculated. Having determined b and n, the value of @/6, for any temperature may be easily calculated, and thence the corresponding values of II/I., W/W., 1887.] for the Change of State from Liquid to Gas. AN and w/w- obtained by interpolation from Clausius’s tables. From _ these P, W, and w are calculated and compared with observation. It is from this comparison of w with the volume of the liquid at various temperatures and pressures that it is evident that « is not constant, for the difference between w calculated and o as observed is by no means so. The following table exhibits some of my results :— OF Gs 100° CS) 200° C. |. 240° Ce |) 242°5° C: 1243. -5°'C: P observed........| 12°24 1695 22434 | 46339 = — P calculated ...... 12-24 1695 ~ 92106 46172 ie ee 49000 WwW ee a. 30-210 284-5 | 19-09 Bae A eae. 3°56 ie ,.. ae 29 -046 Pea iocapl | B88 anaes lo ee ss. ..| 0-177 0-389 1-003. 2°43 See ae ee 2 zea) 18001 1-796 | 2-614} 2-025 | = © ee 1-037/ 1-001! 0-793 | 0-184 | —0-065 ape In some of these cases, as for example for W at 0° C., itis very difficult to interpolate accurately into Clausius’s tables, and similarly for the values of w near the critical point, and I consequently do not attribute much accuracy to these values. On the whole, however, I think that, considering the enormous range of values to be represented by the formula, it is most remarkably accurate. When we compare the calculated and observed volumes of the liquid, in which case a is of importance, we find that no constant value for « can make them agree, for « obviously diminishes with increased temperature, and near the critical point the value of @ for the liquid and gaseous states is not the same. All this means of course that Clausius’s formula does not apply accurately to the case of alcohol. Clausius has not, as far as I can find, applied his formula to calculate the volumes of liquids, and without doing so the want of constancy in « would not appreciably affect the result. Messrs. Ramsay and Young have made observations of the volume of the liquid at various temperatures and pressures, and I have compared some of their results with the formula. In this way it can be seen that « must be made a function of the pressure as well as of the temperature. I have calculated the values of v — @ at certain temperatures and pressures, and find at 110° C.— RG 0 Prof. G. F. Fitzgerald. Clausius’s Formula [Mar. 31, Pressure. 2362 60,000 » — a(calculated) ....-...... 0-409 0-383 a (observed)... .% seer meee 1°417 1 °3925 Gea cwisis viele = ss) sinie eee ee 1-008 1°0095 At 200° C.— Pressure. 22,434. 60,000. - v—a (calculated) .........06 1-003 0°858 » (observed) 5 .o0ewe « sjee sees ee 1°793 1-720 ac Siiclin ee rey aiihc & oleiel ielen eile ar ei autare 0°793 0 *862 At 240° C.— Pressure. 47,500. 60,000. vo—a (calculated) .......0+e05 2°166 1°641 » (observed) 2.2.20.) ...bcdbieues 2-468 2 °169 Laie) sis sis alaie a Wiehe lsheiain ere iil 0°298 0°528 From this it is evident that « diminishes with increased temperature, and increases with increased pressure. Notwithstanding this, that Clausius’s formula does not at all accurately represent the state of the liquid, there is no doubt that it gives a wonderfully accurate general representation of the more important features of the change of state. In this respect it is of enormously higher value than the formule that only give the relations connecting the temperature and pressure of saturated vapours. In addition to this, which it certainly gives in a rather complicated way, it gives the state of the liquid and gas before and after as well as during evaporation, and enables us to calculate points on the theoretical continuous isothermal connecting the liquid and gaseous states. I! have calculated enough of these points to roughly sketch in these curves that cannot be made the subjects of experimental investigation 1887.] for the Change of State from Liquid to Gas. 221 by the usual methods, owing to the instability of the states they represent. Clausius’s equation may be put into the following form by assuming p/(RT) = y and v—a’= a— a y(eta)? = (e+)? - aD) From this it is evident that an isothermal is a quartic curve having asymptotes y=0, x= 0, and w+y a double asymptote at a cusp at infinity, so that the point at infinity on this line is a multiple point of a high order. If we calculate the positions of the points of tangency of tangents parallel to y = 0, for which consequently dy/de = 0, we have the cubic equation— iw Qe (c+4)? = 5 and when twe of its roots are equal 6, = 374° and this determines the critical isothermal. The quartic consists of three branches. One, a serpentine branch, lies in the positive region of and mostly of y, and is the only branch of physical interest at present. The other two branches le entirely in the negative region of zand y. One of these is somewhat parabolic, and les between « = 0 and x = —y asymptotic to both of them, the other is hyperbolic and asymptotic to x = —y and toy=0. The always real solution of the cubic that determines the points where dy/dz = 0 for positive values of © and 4 is a point on the parabolic branch of the curve that lies between « = 0 and x = —vy. The other two roots, when real, determine the highest and lowest points on the serpentine part of the curve that lies in the positive region of # The accompanying diagram represents the general Fie, 1 : c /L+ aM 229 Prof. G. F. Fitzgerald. Clausius’s Formula [Mar. 31, features of this class of curve. It is the particular case of the quartic — (L+aM)?(M? — LN) = 0LM?, where L, M, and N are lines in which M is the line infinity, and L and N are at right angles. In the general case this quartic is a continuous curve with a cusp at the intersection of L and M and L+aM as the cuspidal tangent, while L is a tangent to another branch that passes through the same point. Its general features are some- thing. like this— Fie. 2. General Feature Diagram. There is generally a double inflexion in the part of the curve outside the triangle L, M, N, and the particular one of a series of such curves for which the two inflexional tangents coincide is what corresponds to the critical isothermal in a gas. It is only what corresponds to the part outside the triangle that is of physical interest. In the particular case of the curves representing the isothermals of alechol, the negative parts of the curve lie at avery great distance 1887. ] for the Change of State from Liquid to Gas. 223 1.2 Critrenl Porn oe Critceaul Tsotheruraul for PFS SC. of p7 CSSUPNC Vapour p 'CSSUTPE line for Lsothermal | at 2070 £7 pe, / FoF W10°C Aces of voluInes. wn x = y H ! ! 1 \ ! 1 1 , \ iT 1 1 ' j 1 \ 1 I ! I ) xxxxThe pogulve peurarolte branches [1¢ an hes reylon hut the highest pow § f= () oven for CF thical Isothermal ts — 2.700. hs Line 04+ Ssr-s5----- { Thase Lwo meel al —246 at the pout Lon ti /s i 7; ‘yperbolic Negative 4rcinch| Lsotheritoal of Tsotherm al for 207 CT. V1 ad. \ 1 { ! * i from the origin compared with the dimensions of the serpentine part of the positive branch, so that it is not easy to represent them both in the same figure. I have calculated several points on the isothermals corresponding to 110° C., 207°5° C., and 243°5° C. 207°5° C. is the isothermal that just touches y = 0, while 243°5° C. is the critical iso- thermal. The dotted lines represent the saturated vapour-tensions for which the areas included in the loops of the curve above and below are equal. The points numbered 1, 2, 3, 4 are specially noticeable points on the curves so numbered in the general feature diagrams. The isothermal 110° C. goes down at the point 1 entirely outside the diagram to a pressure of —246,800 mm., and intersects its vapour- pressure line outside the diagram to the right at a volume of 206. The negative parabolic branch of this isothermal only comes up at the point 3 to a pressure of —4,442,000 mm., while the corresponding points of 207°5°C. and 243°5° C. come only to —4,044,060 mm. and — 2,743,000 mm., so that they are very far off. In the isothermal 207°5° C. the point 4 lies at about « = —32, p = —32,000, so that it is not very far off. What strikes me as most remarkable about these curves and other 224 Mr. H. Tomlinson. The Influence of [Mar. 31, than what one might have expected, is the very great distance to which the point 1 descends at ordinary temperatures. It would be interesting to compare the forms of these parts of the curve for several liquids, and see whether there was any connexion between it and the capillarity. | U1. “The Influence of Stress and Strain on the iene Pro- perties of Matter. Part III. Magnetic Induction.” By HERBERT TOMLINSON, B.A. Communicated by Professor W. Grytus ApAmMs, M.A., F.R.S. ca March 17, 1887. (aera: ) “The author lays before the Society the results of experiments extending over a period of ten years on the effects of stress and strain on the magnetic permeabilities of iron, nickel, and cobalt. Two methods were employed. In one the metal to be tested— usually in the form of wire—was placed with its axis coincident with that of a magnetising solenoid, in most cases of considerable length as compared with the diameter of the wire ; round the central portion of the solenoid was wrapped a secondary coil. A similar pair of primary and secondary coils, with a similar piece of the same speci- men of metal, was balanced against the first by means of resistance coils, so that on closing the magnetising circuit no deflection was pro- duced in a delicate Magee or s galvanometer suitably connected up with the resistance coils and secondary coils. The alteration of mag- netic permeability produced by stress was measured by the change necessary to be made in the resistance coils in order to restore the balance. In the second method the resistance coils were dispensed with, and only a metal core used in one of the two pairs of solenoids which were | connected in series each to each. The arrangements were such that the pairs of solenoids, when without any cores, balanced each other’s effects on the galvanometer, so that the deflections of the latter instru- ment were due only to the magnetic permeability of the metal to be tested. The alteration of permeability was in this case measured by the change of deflection produced in the Thomson’s galvanometer. The second method was the one principally employed. In all cases, where it is advisable, the results are either given in ©.G.S. units, or data are supplied for reducing to these units; more- over, the author has endeavoured to separate, as far as possible, the effects of stress on the permanent and on the temporary permeabilities of 1887.] Stress and Strain on the Properties of Matter. 225 the metals,* which effects are for the most part opposite in nature. The paper is illustrated by a large number of curves showing the relations between magnetic permeability and stress and strain at different tem- peratures from 0° C. to 300° C. and upwards. The information con- ‘veyed by these curves it is impossible to adequately represent in an abstract, but the following are among the chief conclusions arrived ait : oe ' 1. When there is no permanent load on an iron wire, and the mag- bictisinig force is small, longitudinal traction of small amount increases the temporary permeability. The increase reaches a maximum very «quickly, as the load increases when further loading begins to diminish the magnetic permeability, until a certain limit has been reached, for which the permeability is a minimum. If the load be carried beyond ‘the above limit the permeability begins to increase again with the ‘load. As a consequence of the above, when the magnetising force is -small there are two critical values of load for which the load produces ‘no effect on the temporary permeability. 2. The first of the two critical values of loading mentioned above diminishes with increase of magnetising force, and finally vanishes when the latter reaches a certain limit. ; On the contrary, the second critical value of loading increases sith the magnetising force. 3. The maximum of temporary permeability mentioned in 1 di- minishes as the magnetising force increases, and occurs at a less and less degree of loading until the latter begins to produce decrease instead of increase of permeability. The minimum of temporary magnetic permeability, on the con- traly, increases with the magnetising force, but,like the maximum, ‘occurs with a lower amount of load the higher the magnetising force. 4. The effects mentioned in 1, 2, and 3 as being produced by load- ‘ing, are modified when a comparatively small load is left permanently on the wire. The modifications are stated in 5, 6, and 7. 5. For small magnetising forces loading produces no effect on the temporary magnetic permeability,’ unless carried beyond a certain limit, Beyond this limit further loading suddenly begins to increase -the permeability. . | 6. For all values of the magnetising force the first critical value of loading vanishes. The second critical value of loading increases with the magnetising force, but for a given magnetising force is much lower than when there is no permanent load. | * By the terms permanent and temporary permeabilities are meant the permea- bility for permanent magnetisation, and the permeability for temporary magnetisa- tion respectively. VOL. XLII, R 226 Mr. H. Tomlinson. The Influence of — [Mar. 31, 7. The minimum temporary permeability increases with the mag- netisingforce up to a certain limit of the latter, but beyond this ea decreases. | &, ‘The permanent magnetic pernentaniye is increased by loading, the amount of increase per cent, being very large for small magnetising forces and moderate loads, but diminishing as the magney eur force increases. : _ 9, The increase of permanent magnetic permeability inentifaeaie in 8 rises in greater proportion than the load up to a certain limit of the latter. Beyond this limit it rises in less proportion than the load, and eventually ceases to rise with increase of load; the value of the dJoad at which this last occurs decreases as the mageleeetee force is increased. 10. For a wide range of ee the effect of the stress on the permanent permeability is opposite in direction to the effect on the temporary permeability. Consequently loading may be found to pro- duce either increase or decrease of permeability according as the permeability we are considering is temporary or permanent. Similarly the total magnetic permeability, since it includes both _ temporary and permanent permeabilities, may be affected by loading in the contrary direction to the temporary magnetic permeability, and the more so as the effects of loading on the permanent magnetic permeability are very much larger than those on the temporary magnetic permeability for a rather wide range both of loading and of magnetising force. 11. The effect of loading—even when carried to a great extent—on the temporary permeability of unannealed piano-steel is very small, provided the wire be not permanently stretched by the load. 12. The effect of loading on the magnetic permeability of anita iron varies very considerably with the amount of previous strain to which the metal has been subjected. 13. When the magnetising force is very considerable and the load small, permanent extension, resulting from previous loading, causes the diminution of temporary permeability produced by the load to be much increased ; also the maximum diminution which can be tempo- rarily produced by loading is increased. When, however, the temporary load exceeds a certain limit, the diminution of temporary permeability produced by the load is lessened by permanent extension. Further, the load which produces maximum diminution of temporary permeability may be considerably lessened by permanent extension. 14, When the magnetising force is small the permanent strain may change increase of temporary magnetic permeability resulting from loading to decrease, provided the load does not exceed a certain limit. 1887.] = Stress and Strain on the Properties of Matter, 227 When the above-mentioned limit is exceeded the effect of the per- manent strain is reversed. 15. The effects mentioned in 12, 18, and 14 are for the most part really the results of subpermanent molecular strain, and can be in great measure removed by severely shaking the wire. 16. The permanent molecular strain which is left on the removal of any load, produces, both for low and high magnetising forces, a per- manent diminution of magnetic permeability increasing with the strain up to a certain amount of the latter. When, however, the strain is such that the wire is sensibly increased in length, the tem- porary permeability increases considerably, and the permanent permea- bility diminishes considerably up to a second limit of permanent _ strain, when once more decrease of temporary permeability sets in. 17. The first maximum of the decrease of permeability mentioned in 16 at first decreases with increase of the magnetising force to nearly. zero; it increases again, however, if we exceed a certain limit of magnetising force. On the contrary, the maximum increase of temporary permeability at first rises with the magnetising force until the permeability is more than doubled, when it begins to fall as the magnetising force is pushed farther. , 18. Mere rest after permanent extension has little or no effect on the alteration of the temporary permeability which is produced by loading, whereas it very perceptibly increases the longitudinal elasti- city of iron, 19. For magnetising forces not exceeding a certain limit there are, for all temperatures between 0° C. and 300° C., two critical values of loading for which no alteration in the temporary permeability is pro- duced by the load (see 1). The value of the load at the first critical point diminishes, and that at the second critical point increases, as the temperature is raised from 0° C. to 100° C. but as the temperature is raised still further the first critical load becomes greater and the second becomes less, until at some temperature between 250° C. and 300° C. the two critical points coincide. : 20. For magnetising forces exceeding a certain limit the two critical points of loading approach each other, at first slowly and then rapidly, with increase of temperature from 0° C. to 300° C. Both critical loads diminish with rise of temperature, but the second more rapidly than the first. 21. The effect of loading on the permanent permeability diminishes with rise of temperature from 0° C. to 300° C. 22, As the magnetising force increases, the total magnetic permea- bility of annealed iron which has not been previously magnetised rises to a maximum and then begins to decline, The maximum permeabi- R 2 228 - Mr. H. Tomlinson.” The Influence of» [Mar. 8, lity seems to occur at nearly the same point of magnetic intensity for different specimens of well-annealed iron of good magnetic permea- bility, but not at the same point of magnetising force. 23. When an iron wire has received previous magnetisation the point of maximum permeability occurs with a higher and higher magnetising force as the previous permanent magnetisation increases. The point of maximum permeability also occurs at a higher degree of magnetic intensity when the wire has been previously subjected to a high magnetising force. 24. Besides a point of maximum total permeability there is a point of maximum temporary permeability which occurs a little before the first-mentioned point. 24 and 23 are in accordance with Maxwell’s extension of Weber’s theory. 25. The temporary permeability is diminished by previous per- manent or subpermanent magnetisation in the same direction. The effect above mentioned may be very considerable, provided the mag- netising force lies between certain limits. 26. When the wire is well shaken after having been previously magnetised by a strong force the temporary permeability is consider- ably restored, and is, moreover, much more nearly a constant for different values of the magnetising force than it was either previously to shaking or previously to suffering permanent magnetisation. 27. More than 90 per cent. of the whole magnetisation imparted by a given force to annealed iron may be permanent or subpermanent provided the magnetising force has a certain moderate value.* When, however, the force is very large the percentage of permanent mag- netism is much diminished. 28. When an iron wire is loaded to a certain limit longitudinal magnetisation has no effect on the thermo-electrical qualities of the metal. The limit of loading mentioned above seems to be the same for a> given magnetising force, as that at which magnetisation has no effect on the dimensions of the wire. 29. The general features of the curves showing the relation between temporary magnetic permeability and load are the same for nickel as for iron. 30. There are two critical points of loading at which the load has no effect on the temporary magnetic permeability of nickel. 31. The load at the first critical point diminishes with diminution of the magnetising force and finally vanishes. _ * This has been already noticed by Ewing (‘ Phil. Trans.,’ 1885, Part TI), in whose important memoir other points of interest connected with magnetic induction “which are mentioned in this paper have been also discussed. : 1887.] | Stress and Strain on the Properties of Matter. 222 On the contrary the load at the second critical point increases as the magnetising force diminishes. 32. The effect of increasing the magnetising force on both the first and second critical loads is therefore opposite in direction to the effect in the case of iron. 33. Similarly the effects non Mcaedl i in 3 are opposite in direction in nickel and in iron. 34. Rise of temperature from 0° C. to 300° C. increases the maxi- mum increase of temporary magnetic permeability, which can be effected by loading nickel wire, and diminishes the maximum decrease. 30. With nickel as with iron the magnetic permeability is not constant, but reaches a maximum. The magnetising force which produces maximum permeability is greater with nickel than with iron, but the magnetic intensity at the point of maximum permeability is less with nickel than with iron. | 36. Nickel wire can by shaking be more effectually de-magnetised than iron. 3/. Well annealed nickel is capable of retaining sigcoaae ae a very large percentage of the whole magnetisation imparted. The maximum percentage retained is, however, not so great as with iron. 38. At acertain temperature the fedeuene permeability of nickel vanishes. The temperature at which this occurs seems to be higher the higher the magnetising force. This last, however, may perhaps be due to impurities in the nickel. 39. The magnetic permeability of nickel rises with the temperature to a maximum and then diminishes. The temperature at which - maximum pemaeability occurs diminishes as oe eC force increases. ALAN eh 40. The temporary effects of compression on the temporax 4 mag- netic permeabilities of iron, nickel, and cobalt, are in the opposite direction to the effects of extension, provided neither the mechanical nor the magnetic stress exceeds a certain amount. 41. The’ temporary effect of traction transverse to the line of magnetisation on the magnetic permeability of iron, is opposite in direction to 1S effect of traction in the same line as the magnetisa- tion. 42. Temporary torsion beyond a ener limit (see 44) increases the temporary magnetic permeability of iron. The amount of in- crease may become very large if the wire has previously suffered permanent torsion or permanent magnetisation in the opposite direc- tion. Ve 43. Permanent torsion decreases the temporary magnetic per- meahbility.. The amount of decrease may become very large if the 230 | Dr. L. C. Wooldridge. [Mar, 31; wire has previously received permanent torsion in the epiate direction. 44, There is for all but very large magnetising forces a critical point of torsion, for which temporary torsion does not affect the temporary magnetic permeability. 45. When the critical point of torsion is passed, the temporary permeability increases with the torsion at first more rapidly than the torsion, and afterwards more slowly until a maximum is reached and the permeability begins to decline. 46. When the wire has previously suffered excessive permanent torsion, temporary torsion which has before produced increase of permeability now produces decrease. 47. The effect of temporary torsion on the temporary néreieailltie of unannealed piano-steel wire is in the same direction as with annealed iron which has suffered excessive permanent torsion (see 46). 48, For a wide range of torsion the temporary permeability and the permanent permeability of annealed iron are oppositely affected by temporary torsion. 49, Fluid pressure does not temporarily affect either the temporary magnetic permeability of annealed iron, or the permanent magnetisa- tion of hard steel, except, it may be, to a degree which is not com- parable with that of the effect of stress applied in any one direction. 50. The application, however, or the removal of fluid stress like that of the stresses of compression, extension, and torsion, shakes out from annealed iron a certain amount of residual magnetism. IV. “Note on a New Constituent of Blood Serum.” By L.C. | WooLprRInGE, M.D., D.Sc., Research Scholar to the Grocers’ Company. Communicated by Dr. Pyx-Smiru, F.R.S. Received March 19, 1887. , : I wish in the present note to draw attention to a proteid substance which exists in very small quantity in blood serum. Owing to the difficulty of obtaining a sufficient amount, I shall not attempt to give a complete description of its chemical characters, but shall confine myself chiefly to its physiological properties which, I venture to suggest, possess considerable interest. It is obtained by rendering undiluted serum distinctly acid by means of dilute acetic or very dilute (4 pro mille) sulphuric acid. Neutralisation does not cause its precipitation ; the serum must have a strong acid reaction. It is constantly present in the serum of dog’s blood, and when collected by the centrifuge it is precisely similar in physical characters to ordinary Peenh Ona New Constituent of Blood Serum. 231 fibrin, and only differs from the latter chemically by being more easily soluble in dilute alkali. It is totally different from the soft granular precipitate of paraglobulin, the latter substance being extremely easily soluble in the slightest excess of acid. It.is also constantly present in serum of sheep’s blood. In the case both of dog’s blood and sheep’s blood it is only present in very small amount, and in the serum from horse blood and bullock’s blood it was absent in the specimens I have examined. The physiological interest of this substance will be seen from the following. . _ It‘is well known that Schmidt regarded two proteid substances as being essential for coagulation. One of these bodies was para- globulin, a substance existing in large quantity in blood serum. Subsequent investigation has failed to confirm this view, and there can be no doubt that paraglobulin is not essential to the process. But Schmidt has obtained results, the correctness of which we are in no way entitled to dispute, which apparently clearly show that the quantity of fibrin formed can be largely increased by the addition of paraglobulin. I think this discrepancy can be explained by the help of this new substance, and this will be best shown by describing the following experiments. Two portions of peptone plasma were taken, and To No. 1, an equal quantity of sheep’s serum was added. ,, No. 2, a small quantity of a solution of the new substance. No. 1, after many hours only presented a scarcely perceptible flocculus of fibrin. No. 2 was quite solid in 15 minutes; on squeezing out the fluid from the clot and again adding a solution of the new substance, ' - the mixture again clotted through and through. Now Schmidt’s experiments were very much of this nature. He found in certain specimens of hydrocele fluid that the addition of fibrin ferment produced very slight clotting, whereas on the further addition of a substance which he regarded as paraglobulin a decided clotting took place. Now sheep’s serum contains plenty of para- globulin and plenty of fibrin ferment, but it has no appreciable effect in my experiments. But this new substance, which it must be remembered ‘is “only present’ in very small quantity in serum, had the most marked - influence, and hence I conclude that it is the new substance, and not paraglobulin, which increases the amount of fibrin. It may be mentioned that in preparing paraglobulin a certain amount of the new substance is always precipitated with the former substance. A second physiological property of this new substance is the effect it exerts when injected into the circulation of a living animal. It is very exceptional to find that the injection of blood serum 232 vey “Profit TOBY Baxley. Ost. snk [Mar. 31, produces any effect, serum containing plenty of paraglobulin and ferment but only traces of the new substance. But the injection of a solution of this body prevents the coagulation of the shed blood. Occasionally as the result of the injection very small thrombi are formed; possibly if more could be obtained con- siderable intravascular clotting might be set up. The following is an example. : A quantity of the new substance obtained bie 300 c.c. sheep’s. serum and well washed was dissolved in dilute alkali and salt solution. (The amount of substance was I estimate 0°2 gram.) This solution was injected into the jugular vein of a rabbit. The blood of this rabbit previous to the injection clotted in two minutes; after the injection the blood drawn off remained quite fluid for three hours— time of observation. It clotted, however, gb on — some of: the solution injected. The injection of considerable quantities of serum or of paraglobulin I have not found to have any appreciable effect. | . Of itself this substance, since it exists in so small aniound is of little interest, but as it appears to vary in quantity in different: animals and under different circumstances, it is easy to see that. misapprehensions as to the influence of paraglobulin on coagulation might easily arise. These observations also throw great doubt on the power of oe ferment to produce a so-called intoxication. This substance has an extremely feeble influence on dilute MgSO, plasma, and hence contains but a trace of fibrin ferment. Since it is closely related to the fibrin-yielding matters of the plasma, and to the tissue fibrinogens I have elsewhere described, I should propose to call it serum fibrinogen, V. “Preliminary Note on the Fossil Remains of a Chelonian Reptile, Ceratochelys sthenurus, from Lord Howe's Island, Australia.” By THomas H. Huxuey, F.R.S. Received March 24, 1887. : The interesting remains of which I propose to give a brief notice in the present. communication, are contained in a friable sandstone | (apparently formed of concreted blown sand), and they have a very. recent appearance. The age of the deposit in which they are found is unknown, but it is probably quaternary. The specimens have been: for some years in the paleontological collection of the British Museum; and, for the most part, they have not yet been submitted toi careful examination. But I learn that. the greater number: of them 1887} Ceratochelys sthenurus. 933: were long since rightly determined to be Chelonian by Mr. Davis, and set aside as such. thi Several of the most important of these numerous and, in general, very fragmentary bones were originally found imbedded close together in the same block of sandstone. They consist of a great part of a pelvis, a caudal vertebra, and an imperfect skull. Of the pelvis, a right ischium and a pubis are imbedded in the rock, while an imperfect right ilium, which fits well on to the ischium, is separate ; all these bones are unmistakably Chelonian. The caudal vertebra has remarkable peculiarities. It resembles an ordinary Chelonian caudal vertebra from the anterior half of the tail, in its general characters; but it is strongly opisthocclous, the centrum having a deep cup behind and a correspondingly curved articular head in front. From the posterior part of the ventral face, two stout pro- cesses diverge, and present terminal rounded facets for the rami of the large chevron bone which must have articulated with them. Asa general rule, the caudal vertebre of Chelonia are proccelous—but Chelydra and Gypochelys (perhaps also Staurotypus and Platysternum) form well known exceptions,* in so far as the vertebree behind the 3rd or 4th are strongly opisthocewlous. In fact, the vertebra in question closely resembles the 6th or 7th of Chelydra or of Gypochelys (see figs. 1. and 2). In the first, however, the transverse processes are Fia. 1. Ch xt - Caudal vertebra of Ceratochelys. N, platform on the neural arch;. pz, pre zygapophysis mutilated ; ¢r, broken transverse process; Chv’, processes for the chevron bone ; Chv, chevron bone. - * The opisthocelous character of most of the caudal vertebre of Chelydra was first pointed out by Von Meyer in his description of the Giningen Chelydre. Baur (“ Osteologische Notizen,”’ ‘Zool. Anzeiger,’ No. 238, 1886) has. gone: fully into the a Prof. T. H. Huxley, On [Mar: 31; ~ Fie. 2. Chy Caudal vertebra of Chelydra. Letters as in fig. 1. very much stronger and the pentagonal platform into which the upper surface of the neural arch expands, in place of a neural spine, is as long as the vertebra instead of being only about half.as long. The stout pre- zygapophysis of the right sideis broken off, leaving only the base visible in the fossil. Two other caudal vertebra, having the same structural features, occur among the detached remains; and belong, like the first, to the second fourth of the tail. Another tolerably complete vertebra, with a considerably longer centrum, corresponds very closely with a caudal vertebra of Gypochelys from the third fourth of the tail. In this, as in one of the foregoing vertebra, the chevron bones are ankylosed with the centrum. I conceive, then, that there can be no doubt that the pelvic bones and these caudal vertebra belonged to a Chelydroid Chelonian, of about the size of the largest ‘‘ Snapping turtles”’ which are met with in North America at the present day. question, and has pointed out’ the exceptional nature of their structure among the Chelonia. Since the above paragraph was written, Dr. Giinther has kindly enabled me to examine a spirit specimen and a skeleton of Platysternum. The caudal vertebree resemble those of Chelydra, except that the last nine are proccelous, while that between these and the more anterior opisthoccelous vertebre is nearly flat at the ends.- In this, as in other respects, Platysternum presents characters inter- mediate between Chelydra and the ordinary Hmyde. Professor Cope (‘ Vertebrata of the Tertiary Formations of the West,’ 1883, p. 111) ascribes opisthocclous caudal vertebree to the Baenida, but no figures or descriptions of such vertebre are given, Of the opisthocelous Chelonian vertebra figured in Plate XXIV of the ‘ Report of Extinct Vertebrata obtained in New Mexico’ (1877) it isexpressly stated that their “correct reference cannot now be made”’ (p. 43). 3887.) - Ceratochelys sthenurus. 2350 ‘Prima facie, the skull found in the same block might also be expected to be that of a Chelydroid; and, in fact, it is-so. I do not base this interpretation on the Chelonian character of the upper jaw, as there are various extinct Saurian reptiles which closely approximate Chelonia in this part of their structure. The diagnostic characters lie in the back part of the skull; and especially in the auditory region, which is altogether Chelonian. Not only so, but when this fragmentary skull is compared with that of Chelydra, the correspondence between the two is singularly exact (figs. 3 and 4). In two respects, however, the fossil differs from Chelydra and Gypochelys. Fie. 3, ‘. : \ fis : Skulls of Ceratochelys (fig. 3) and Chelydra (fig. 4); the latter of the natura size, the former much reduced. The portion of the skull of Chelydra which corresponds with the fossil is shaded. 1. The roof over the temporal fossa formed by the parietal, post- frontal, and other bones, which leaves the auditory region uncovered in the recent genera,* extends back, beyond the occiput, in the fossil, and sends down a broad vertical rim from its margin. * The ‘roof’ extends much further back in Platysternum. 236° Prof. T. H: Husley. On [Mar. 31; 2. The upper surface of the cranial shield is, at most, rugose in the recent Chelydride ; in the fossil, three strong conical processes, Jike horn-cores, of which the middle is the longest, are developed from its posterior and lateral region.* | This skull is described and figured in the ‘ Philosophical Trans- actions’ for 1886 (Plate 30, fig. 1) by Sir R. Owen, under the generic or subgeneric name of Mezolania, and is said to belong to a Saurian reptile closely allied to the “ Megalania prisca”’ described in earlier communications. But the skull is assuredly that of the Chelydroid Chelonian to which the pelvis and caudal vertebra belong. What Megalania prisca may be I do not pretend to say; but the remains which I have described can have nothing to do with any Saurian reptiles ; and I propose to confer on the genus of Chelonia to which they belong the name of Ceratochelys. The singular osseous caudal sheaths described by Sir R. Owen, in the samme memoir, also appertain to Ceratochelys. They formed part of the series of remains sent to the British Museum along with the foregoing, in which none but Chelonian bones have yet been discovered; and the remains of vertebre left in these sheaths are similar to the caudal vertebre of the terminal fourth of the tail in the Chelydride. The Snapping turtles are noted for the length and strength of the tail and for the strong, laterally compressed, acuminated “scales ’’ which form a crest along the median dorsal line, while others, less strongly keeled, lie at the sides of the tail. In many Chelonia, the extremity of the tail is enveloped in a continuous sheath, These and other scale-like structures in the Chelonia, are usually spoken of as if they were entirely epidermal. But, a day or two ago, Dr. Giinther informed me that in the Australian Tortoise, Manouria, the great imbricated scales of the limbs contain bony scutes; and that similar scutes are to be found in Testudo greca. This of course, suggested the examination of the caudal scales of Chelydra and Gypochelys ; and, having been enabled by Dr. Ginther’s kindness to examine the caudal scales of a good sized specimen of the latter, I have found that those of the crest contain bony scutes.t The bony scute corresponds very closely in form with the whole “scale,” but the recurved apex of the latter is formed only, by epidermal subse (figs. 5 and 6). pe The living Chelydra, therefore, has a.caudal armature which, in * It is possible that these may be dermal bones coherent with the proper cranial shield. + The fact is noted by Riitimeyer (Lang and Riitimeyer, ‘Die Fossilen Schildkréten von Solothurn,’ ‘Denkschriften der Allg. Schweiz. Gesellschaft,’ vol. 22). The armature of the tail in Platysternum is for the most part arranged in zones, of four plates in each zone; but I have not yet been ull to find any bone in them. ba a Mole Cénatocicly® Shevartsnnt) 100 ott Bam Fig. 5. 7 N.S. = as = 2! eee tee? = = Pr . Se Sectional views of a scute of the tail-armour of Ceratochelys (fig. 5), and of one of the crest plates of Gypochelys, both of the natural size. _ principle, is similar to that of Ceratochelys, but the osseous elements ‘are relatively atrophied. There is exactly the same relation between the armour of species of living Crocodiles and Alligators, on the one hand, and those of Jacare and Caiman and the extinct Teleosauria, on the other. In the former, the epidermal scales remain well developed on the ventral side of the body, while the corresponding osseous scutes, fully developed in Jacare, Cavman, and Teleosauria, have vanished. Among the detached fragments to which I have referred, there are remains of ribs, with their costal plates; marginal and other plates of the carapace; parts of the plastron; part of a scapula; sundry limb bones; and several of the cranial processes called ‘“‘ horn-cores.” They all agree, so far as they can be compared, with the determination already arrived at; which, to sum it up in a few words, is that the remains of crania and caudal sheaths from Australia, hitherto referred to Saurian reptiles, under the names of Megalania and Meiolunia, appertain to a hitherto unknown species of Chelonian, Ceratochelys sthenurus, closely allied to the living Chelydra, Gypochelys, and Platy- sternum. The evidence of this fact offered | in the present note appears to me to be conclusive, but it may be desirable hereafter to figure the parts mentioned and to describe them at length. | _ The interest which attaches to the discovery of this tasaies -‘Chelonian arises partly from the fact, that the group of Chelonia to which it belongs is wholly unrepresented in the faunaof Australia, as at present known. Platysternwm is usually said to be found in China. Dr. Gunther, however, informs me that Upper Burmah is’ its proper 938 Drs. T. L, Brunton and J. T. Cash.’ Action of [Mar. 31, habitat ; otherwise, North America, east of the Rocky Mountains, is the nearest region in which the Chelydride are to be found. But Chelydride, and, indeed, species of the genus Chelydra, occur in Upper Miocene (CHningen) and in EKocene formations in Europe, Moreover, Platychelys,.of the Upper Jurassic series of Bavaria and Switzerland is regarded by Ritimeyer as an early form of the group. Lord Howe’s Island is about 200 miles from the nearest Australian mainland, and something like 400 miles, as the crow flies, from the Darling Downs, in which the caudal armour, which has been ascribed — to Megalania, was found, The discovery of Ceratochelys, therefore, has an interesting bearing on the question of the former extension of Australia to the eastward, on the one hand; and of the possible derivation of such forms as Ceratochelys from Asia, on the other hand. An elevation of the sea bottom of 6000 feet would place Norfolk Island and Lord Howe’s Island on a peninsula extending from the region of the present Barrier Reef to New Zealand; and the Flore and Faune of those islands are known to have special affinities with those of New Zealand and none with those of Australia. Speculations respecting the origin of the Chelonian carapace, are suggested by the discovery of osseous scutes in the vertebral region of the tail, and their coalescence in Ceratochelys to form a sort of caudal carapace, ridged in a manner resembling that of Chelydra and Platychelys. But the consideration of these points would take me beyond the limits of the present note, VI. “Action of Caffem and Theine upon Voluntary Muscle.” By T. LaupER Brunton, M.D., F.R.S., and J. THEODORE CasH, M.D. Received March 24, Loot, J From a number of experiments we have found that caffein and theine both cause rigor in the voluntary muscles of frogs. All these experiments were made on Rana temporaria and none on Rana escu- lenta. The action is, however, very variable, the rigor being some- times exceedingly well marked, and at other times not observable. The alteration does not depend on the dose of the alkaloid. When the gastrocnemii of the same frog were treated with solutions of caffein or theine of different strengths, the stronger solution had the most powerful action; but when different frogs were used, a large dose sometimes had little action on one frog, while a small dose had a powerful action on another. Theine seems to be rather more powerful than caffein, but the quantitative difference between them is slight. There is, however, a marked qualitative difference between them, inasmuch as theine tends to produce rhythmical contractions in the muscle, Complete curarisation quickens the occurrence of rigor, A 1887.) Caffetn and T. heine upon Voluntary Muscle. 239 variation is observed in the action of the alkaloids on the different muscles of the same frog. In the triceps the rigor is more rapidly developed, and more extensive than in the gastrocnemius. In the sartorius rigor commences soon, increases rapidly, lasts for some hours, and then relaxes. The addition of lactic acid to a solution of theine or caffein causes the rigor to appear sooner, develop more rapidly, and attain a sreater maximum. Potash retards and diminishes the action of theine or caffeine. Guanidine produces at first its characteristic clonic con- tractions, but these pass off long before the rigor of caffeine or theine begins, and the appearance of the rigor is postponed as com- pared with the rigor of theine or caffein alone. On comparing the effect of guanidine with that of chloride of barium, we found that in the case of the guanidine the rigor was longer in occurring, and its maximum was greater than that produced by barium salts. The addition of chloride of calcium to the solution of theine quickens rigor and makes it more extensive. One phenomenon which seems deserving of attention is the rhythmic contraction of the muscle pro- duced by theine. This rhythm is so slow that it would escape attention unless a very low rate of speed were used in the recording appa- ratus; it is sometimes as slow as from three to about one contraction per hour; it may continue for twenty hours. The rhythm is usually produced by small doses of theine, which do not cause a marked rigor ; it may, however, occur at the commencement of what develops into a lasting rigor, or at the relaxation of a pseudo-rigor, by which we mean a phenomenon which might also be termed tetanic relaxation, The rhythm is more rapid at the commencement of its occurrence and slower towards its termination; it may be as rapid as twenty relaxations and contractions in an hour, or as slow as between one and two in an hour, The total extent of contraction and relaxation is very small, amounting to about one-fifth of a millimetre. At first the contractions and relaxations are equal in duration, but afterwards the relaxations become more rapid and the contractions slower. In one instance we observed the remarkable phenomenon to which we have given the name of pseudo-rigor; in this experiment the application of the theine was followed by slight relaxation of the muscle, to this succeeded an equal contraction, and then followed great relaxation below the normal, so great indeed that the negative curve below the abscissa strongly resembled the positive curve of contraction due to rigor in most other experiments.* * This phenomenon is difficult to explain, but it suggests the possibility of a transverse as well as a longitudinal contraction in muscular fibre.—March 29, 1887. 240 TM want’ pesendae 9S Sa VIL. “ Contributions to our Knowledge of the Connexion between Chemical Constitution and Physiological Action. Prelimi- “nary Communication on the Action of certain Aromatic _ Bodies.” By T. LaupErR Brunton, M.D., F.R.S., and _ J. THmopore Casu, M.D. Received March 24, 1887. The distinctive action of the lower members of the fatty series is their stimulant and anesthetic action on the nerve-centres. The members of the aromatic series also affect the nervous system, ut they appear to affect the motor centres more than the sensory, so that instead of producing anesthesia, like the members of the fatty series, they tend rather to produce tremor, convulsions, and paralysis. Benzene, chlorobenzene, bromobenzene, and iodobenzene are all ‘somewhat similar in their action on frogs; the halogen radicals not ‘modifying the action of the benzene to such an extent as they do in ‘the case of ammonium salts. The voluntary muscles are weakened ‘-by them, and there is a slight tendency to paralysis of the motor nerves; but the action is chiefly exerted upon the brain and spinal cord. The brain is first affected, as shown by general lethargy and ‘disinclination to move. Next the cord is affected ; motions are imper- fectly performed, and there is a tendency to general tremor on move- ment resembling that observed in disseminated sclerosis; sometimes, however, the tremor is observed independently of movement. The addition of hydroxyl to the benzene nucleus intensifies the onvulsant action, so that oxybenzene (carbolic acid) and dioxy- ‘benzene cause convulsions in frogs, and trioxybenzene causes jerkings, though of a slighter character. - The Society then adjourned over the Easter Recess to Thursday, April 21st. 7 3 Presents, March 81, 1887. Transactions. : . Calcutta :—Indian Museum. Catalogue of Siwalik Vertebrata. Parts I-LI. 8vo. Calcutta 1886. Catalogue of Pleistocene and Pre-historic Vetebrata. 8vo. Calcutta 1886. The Museum. Cambridge, Mass. :—Harvard College. Bulletin of the Museum of — Comparative Zoology. Vol. XIII. No. 2. 8vo. Cambridge 1886. The Museum. Frankfurt-am-Oder :—Naturwissenschaftlicher Verein. Monatliche Mittheilungen aus dem Gesammtgebiete der Naturwissen- schaften. Band IV. Nr. 1-12. 8vo. Berlin 1887; Societatum Litterze. 1887. Nos. 1-2. 8vo. Berlin. The Union. Beet ey Ae Presents. ; 241 Transactions (continued). London :—Anthropological Institute. Journal. Vol. XVI. No. 3. _ 8yvo. London 1887. . The Institute. Middlesex Hospital. Reports. 1885. a5 London 1887. The Hospital. Royal Institute of British Architects. Journal of Proceedings. Vol. ITI. No. 11. 4to. London 1887. The Institute. Odessa :—Société des Naturalistes dela Nouvelle-Russie. Mémoires (in Russian). Tome XI. Nos. 1-2. 8vo. Odessa 1886-87. ° The Society. Philadelphia :—Academy of Natural Sciences. Proceedings. 1886. Part 3. 8vo. Philadelphia 1887. The Academy. Stockholm :—Kongl. Vetenskaps Akademie. Ofversigt. Arg. 4A, No. 1. 8vo. Stockholm 1887. The Academy. - Turin:—R. Accademia delle Scienze. Atti. Vol. XXII. Disp. 4-6. 8vo. Torino 1886-87. The Academy. Vienna :—K. K. Geographische Gesellschaft. Mittheilungen. Band XXIX. 8vo. Wien 1886. The Society. Adler (M.N.) The Temple at Jerusalem. 8vo. London 1887. The Author. Caruel (T.) Flora Italiana. Vol. VII. 8vo. Firenze 1887. ) Professor Caruel. Jones (T. Wharton), F.B.S. Rule in Ireland from St. Patrick to Cromwell. 8vo. Ventnor 1887. The Author. Mouchez (E.) La Photographie Astronomique a4 l’Observatoire de Paris et la Carte du Ciel. 8vo. Paris 1887. The Author. Plantamour (Ph.) Des Mouvements Périodiques du Sol. 8vo. Genéve 1886. The Author. Schifer (H. A.), F.R.S. Uber die Motorischen Rindencentren des Affen-Gehirns. 8yo. [ Leipzig 1887. ] The Author. Ter Gouw (J.) Geschiedenis van Amsterdam. Deel V. 8vo. Amster- dam 1886; Map of Amsterdam in 1544. Twelve sheets. Reprint, Obl. 4to. Amsterdam 1885. The Magistracy of Amsterdam. VOL. XLII. Ss 242 Mr. C. Spurge. On the Effect of Polish on the “On the Effect of Polish on the Reflexion of Light from the Surface of Iceland Spar.” By C. Spurcz, B.A, St. Catherine’s College, Cambridge. Communicated by R. T. GLAZEBROOK, M.A., F.R.S. Received November 18,—Read December 16, 1886. Revised March 3, 1887. I. Introduction. The optical effect of polishing the surface of a transparent body has received the most complete investigation at the hands of Seebeck,* and till very recently+ Seebeck’s were almost the only experiments made on the subject. Seebeck’s method consisted in observing with a Nicol the light of a lamp reflected from the surface of the body. By means of a divided circle, the angle of polarisation was measured, and it was from an alteration in this angle that a change in the state of the‘surface was inferred. But it has been since shown by Jamint that, when plane polarised light is incident upon the surface of a transparent body, the reflected light is in general not plane but to a measureable degree elliptically polarised, and consequently there is no angle of incidence at which the light can be completely quenched by a Nicol. It follows that, as regards our present state of knowledge, Seebeck’s investigation is to some extent incomplete, and also that there is some uncertainty in the determination of the angles of polarisation, which may affect our conclusions as regards the state of the surface, especially since the difference produced by polishing is according to Seebeck not very large. Both Sir David Brewster§ and M. Jamin were of the opinion that Seebeck’s experiments should be repeated, and the latter promised to consider the effect of polish later on but appears never to have done so. Mr. Glazebrook kindly pointed out to me that the subject presented a suitable field for research, and, at his instance, I undertook the present investigation. My object has been to attain greater accuracy than hitherto by employing for an analyser a quarter undulation plate in addition to a Nicol, so as to make the extinction of the reflected light very complete. The angle of incidence of the polarised light falling on the surface of the crystal was kept constant, in order to measure as dvrectly as possible the alteration produced by change of polish. Both the azimuth of the major axis and the ratio of the axes of the elliptically polarised light were calculated. These quantities furnish * ©Poggendorff, Annalen,’ vol. 20, 1830, p. 27; vol. 21, 1831, p. 290. + Sir J. Conroy, ‘ Roy. Soc. Proc.,’ Feb., 188€. ft ‘Annales de Chimie,’ vol. 29, 1850, p. 263. § ‘Edinb. Journ. S8ci.,’ vol, 5, 1831. Reflexion of Light from Iceland Spar, 243 us with two independent tests of a change of surface, and completely determine the nature of the light, so that a knowledge of their values before and after polishing enables us to state the precise alteration produced in the reflected light, a question which has never been investigated, and is, I believe new to this paper. II. Apparatus. A series of preliminary experiments were made to discover what apparatus was best suited for the investigation. JI found that, whether a Nicol or a Nicol and a quarter undulation plate were used as analyser, it was best to polarise the light before incidence. Also, observations showed me that a Nicol and a quarter wave plate were a more sensitive arrangement than a simple Nicol, supposing that in each case the light was polarised before incidence. I have therefore deemed it necessary to employ the Nicol and quarter wave plate arrangement in order to secure all the accuracy that is possible by completely quenching the reflected light. The instrument I used was an elliptic analyser kindly lent for the purpose of these experiments by Professor Stokes. A very full description of the instrument will be found in the ‘Phil. Mag.’ for 1851, but the following abbreviated account is given in order to explain the way in which it was used during the course of the experiments. The elliptic analyser consists of a brass annulus attached to a vertical stem which fits into a hollow cylindrical foot. When the foot is placed on a table, the plane of the annulus is vertical. Within the annulus turns a brass graduated disk; and the angle through which it turns is read off by means of verniers engraved on the annulus. These verniers are therefore fixed. The disk is pierced by a central aperture on the side of which opposite the incident light is a screw thread, so that a cell containing a quarter wave plate can be screwed into the disk. In front the disk carries a hollow cylinder turned in the lathe with the disk itself. Round the cylinder turns a collar into which is screwed a tube containing the analysing Nicol. The collar carries a pair of level edged verniers by which the angle may be read off through which the Nicol has been turned. These verniers are therefore moveable. Thus the quarter wave plate moves in azimuth, carrying the Nicol along with it, and the Nicol has likewise an independent motion in azimuth. In observing, the light is extinguished by a combination of the two movements, in which case the elliptically polarised light is converted by the quarter wave plate into plane polarised, which is then quenched by the Nicol. There are two principal positions in which the light can be quenched, and, since either Nicol or quarter plate may be reversed by turning through 180°, there are four subordinate positions corresponding to $2 244 Nie Spurge. On the Effect of Polish on the each principal position. The position of the Nicol is determined by the readings of the two moveable and that of the quarter wave plate by the readings of the two fixed verniers. Thus each principal position is determined by eight readings, and in the ah wanes follow, each number is the mean of eight readings. Suppose that R, R’ are the mean readings of the fixed, r, r’ the mean readings of the moveable verniers, then the quantities, which it is the object of the present investigation to determine, are tan aw, the ratio of the axes of the ellipse, I, the azimuth of the major axis of the ellipse, and these are given by the formule— cos 27 = sin (7’—7r)/sin (R’—R), and fiw oid) These equations determine w absolutely, but I will be measured from an arbitrary zero which will remain fixed so long as the quarter plate is not unscrewed from its containing tube, but which will be changed by a constant amount, if for any reason it is unscrewed and rescrewed up. A subsidiary quantity is p, the retardation of the crystal plate, which may be determined by means of the equation, cos p = tan (7r’—r)/ tan (R’—R ys The source of light employed was an Argand burner, the rays from which were polarised by means of a Nicol before incidence. Jil. Adjustments. The tube.of the polariser was levelled and its axis placed in a direct line with the centre of the flame. The height of asmall brass table, on which the crystal was placed was adjusted so that the reflected light passed through the tube of the analyser. A number of ‘preliminary observations were made to determine the best angle of incidence, 1.e., the angle at which the extinction was most Sek The "Gh position of the analyser having been found, the centre of the tube of the analyser was adjusted to the same height as the centre of the tube of the polariser and the centre of the face of the crystal. The tube of the analyser was so directed that a ray of. light from the centre of the flame passing along the axis of the polariser was reflected so as to enter at the centre of the tube of the analyser and leave at the centre of the tube. cae As the present experiments were directed to discover a difference which at the outset was recognised as possibly small, especial care was taken to secure fixity of position in the parts of the instrument and in the position of the face of the crystal of Iceland spar. Reflexion of Light from Iceland Spar. 245 The instruments-were firmly attached to a laboratory table, and before commencing the moveable parts were examined and tightly screwed up. Round the base of the table and the foot of the analyser a small quantity of melted paraffin was poured so as to form con- necting links from one part of the apparatus to another. From time to time these links were examined and found to be unbroken. To attach the crystal to the table, hard electrical cement was used. The plan finally adopted was to place the crystal on the table, and to fix it by pouring a small quantity of melted wax down the back of it. Since the crystal was removed from the table to polish its surface, some means of restoring it to its original position were needed. The following optical method was employed. A circular diapbragm with a central pinhole was fitted to the brass tube containing the polarising Nicol. If the pinhole were slightly eccentric, the position of the hole would change as the disk rotated in its plane. To obviate any such alteration, a radius was drawn on the diaphragm which was set so that it was horizontal and always pointed in the same direction. In front of the source of light was placed a screen having a small hole at the same height as the pinhole in the diaphragm. The position of the screen was defined by lines drawn on the table. Thus only a single ray of light was allowed to fall on the surface of the crystal, viz., that passing through the apertures in the screen and diaphragm. As these apertures could always be replaced in the same position, the direction of this incident ray was a fixed horizontal straight line. In a similar manner a circular diaphragm with a central pinhole was fitted to the brass tube containing the analysing Nicol, and some distance in front of this tube was placed a screen with a pinhole at the same height as the pinhole in the diaphragm. The position of the screen was defined as before by lines drawn on the table. A radius was drawn on the diaphragm, and also, since the tube itself was moveable, a mark was made on it so that it could be turned into the same position. The crystal was placed on the brass table so that its plane was vertical and passed through the centre of the circular top. On placing the eye opposite the aperture in the screen facing the elliptic analyser, it was found that-a bright dot of light was visible. Thus the horizontal incident ray already mentioned must have been reflected by the crystal surface so that it passed through the apertures in the screen and the diaphragm fitted to the analysing tube. These apertures could be replaced in the same position, and therefore the direction of the reflected ray was a fixed horizontal liue. Consequently the normal to the surface of the crystal bisecting the angle between the incident and reflected rays was a fixed direction. Supposing the crystal to have been taken down for polishing, it 246 Mr. C. Spurge. On the Effect of Polish on the could be restored to position by placing the diaphragms and screens in their proper stations, and setting the crystal so that a bright dot of light was visible to the eye in front of the last screen. The only possible changes in position that this method allows are a displacement parallel to the table and a rotation of the face of the crystal in its own plane. The former was prevented by means of fixed marks on the table, and the latter by taking every precaution to leave the base of the crystal in contact with the table unchanged, and later on by the use of a template. A series of experiments were made to determine whether the dia- phragms and screens could be removed and replaced in exactly the same positions. For this purpose the screens and diaphragms were removed one ata time and replaced, using only the setting lines. It was found that the dot of light remained visible, while the slightest displace- ment of the screens caused it to disappear. During each set of experiments the screens and diaphragms were frequently replaced to determine if the crystal remained unmoved. The surface of the crystal was shielded during the day by a box with apertures, and completely covered at night. In taking the readings the quarter wave plate and Nicol were turned into such positions that the centre of the field was as dark as possible. IV. Hzperiments made with a Natural Face. Observations were now made with the light reflected from that natural face of the crystal which seemed the best. The results are given in Tables I, II. The observations made with the crystal were always consecutive, none being rejected after the first satisfactory observation had been taken. Table I.—Observations with a Natural Face. Mean Temp. 15°3 C. ge r. R’. | R. (7’—r). | (R’-RB). 90 562° 4°G01° 153 *895° 62°475° 85 -961° 90 585 4 °565 153°781 62 °286 86°020 90 350 4°334 153 °955 62° 256 86 -016 90 -293 4 °324 154 ‘002 62°516 85 °969 90 285 4°525 153 *840 62°462 85 *760 90 454: 4°594 153° 852 62°314 85 *860 90°278 4° 430 153 -790 62°408 85 848 99 *362 4°321 153 *888 62 315 86 -041 90 °486 4°470 153 * 866 62°339 86 -016 90 045 4°525 153 833 62 °215 85 *520 90 °287 4.°545 153 °433 62°317 85 °742 90 *370 4-470 154 °020 62 °264 85 * 900 90 °312 4-450 153 *687 62°285 85 *862 Means..| 90°359 4 47 3 153 *834 62 °342 85 ‘886 Reflexion of Light from Iceland Spar. 247 Table II. aw. tan a. I. @ fo} 1 53-5 0 03303 108-185 1 50°8 0: 03225 108-033 1 48-1 0-03145 108 °105 1 525 0 03275 108-259 2 0°3 0-03501 108 ‘151 1 5503 0 -03356 108 -083 1 575 0-03419 108 099 1 49° 0 03172 108 °101 1 50-4 0 -03212 108 102 2 54 0 -03648 108 -024 2 3-2 0 -03585 107 ‘875 r 51-2 0 -03236 108-142 1 56°8 0 03399 107-986 Means.. 1 54°9 0:03344 108 -088 Taking from Table I the mean values of R'—R, r'—r, we have— sin (r'—r) _ sin 85°886 Seven Tm 01 498 wan le cos 2a = Thus » = 1°55’, and we obtain for the values of the quantities which determine the nature of the polarised light, tan 7 = 0°03346, TF = 108-083 - We have to find whether these two quantities are altered by polishing. The subsidiary quantity p is given by— tan (r’—r) — tan 85°886 _ Sh) nel aoe cos p = Weare calculating p merely for the purpose of verification, and are not using it to determine the nature of the polarised light. Take, then, p to be the least positive angle which satisfies the last equation. Thus p= 111° 14. This is the mean value of p. To estimate the error in determining p, take the 12th set of observations in Table I. We have— tan 85°900 _ fan 91-756 42768; cos 2) — whence p = 115° 19’. There is thus a difference of 4° in the extreme value of pfrom the mean. The cause of this apparently large varia- tion in the values of p will be considered later on. 248 Mr. C. Spurge. On the Effect of Polish on the _ V. Determination of the Inclination of the Natural Face to the same Face Polished. The crystal was taken down from its position on the brass table, and, in order to ensure that the face from which the light was reflected was ground parallel to itself, the inclinations of the face to two other faces which were left untouched, were obtained before and after polishing. The measurements were made in the usual way with the spectrometer. It was found that a fair image of the slit could be obtained by reflexion at each of the faces. Three times the crystal was completely dismounted and measurements of each angle taken. Before polishing. After polishing. First angle. | Secondangle. | First angle. .| Second angle. 1055. 56 Hh 58187 1 105, 6 Be va Solon 105° © 15 Wego Of 105) Be 74 58 22 Os Wee Py Be 7a), 108 5. ag 74 58 50 Means..| 105 6 29 74 58 35 105 5 37 74 58 44 - The angles are almost unaltered and the differences are within the limits of experimental error. Lines were drawn round the sides of the crystal parallel to the edges, and after polishing remained still parallel, which was an additional confirmation. The conclusion at which we arrive is that the polished face was ‘parallel to the natural face. , VI. Method of Polishing the Crystal. The natural face which had been the subject of the experiments recorded in Tables I and II was polished. The polishing was per- formed by myself to ensure an exact knowledge of the treatment it received. I am indebted to Professor Threlfall for the use of the apparatus and materials. As previous experimenters seem to have experienced a difficulty in obtaining a surface polished in the same manner, it may be well to state the exact mode of polishing the surface. That the crystal might be polished under the same conditions of pressure, a rectangular block of lead was cemented to the crystal. In polishing especial care was taken not to press on the crystal down- wards, but to exercise only lateral pressure. The crystal was first polished with emery on a plate of glass which had been rendered plane by grinding ona slate. The emery was prepared as follows: Reflexion of Light from Iceland Spar. 249 some very fine emery was scattered over a tub of water and allowed to settle; after standing for a number of minutes, the lhquid was poured off, and the sediment, which was deposited on standing for a further number of minutes, was preserved for use. Five kinds of emery were used, viz. :— Stood 1 minute, deposited in 5 minutes. | 99 5 99 15 99 wt Le ,9 B0F > aol _ 25 hours. i 2 HOWES!*...3, 40 2 The crystal was polished about twenty minutes with each kind in a perfectly quiet room to avoid dust being deposited on the glass and causing flecks in the crystal. Next a bed of refined pitch was prepared having its upper surface perfectly plane. Upon this the crystal was polished with rouge for about three hours. Finally, the surface was carefully cleaned by washing it in a stream of water. VII. Heperiments made with the sume Face Polished. The screens were carefully set in their places, and by means of these the crystal was fixed in the same position as formerly by the method described towards the end of Section III. Then the observa- tions recorded in Table III were taken consecutively. Table I1].—Observations with a Polished Face. Mean Temp. 14°85° C. 91-066 90 *907 = EbsS 153 °736 €2°295 | 86°948 | 91°441 "084: 153 °410 62 *200 86°823 | 91°210 [is t. R’. R. (r’—r). | (R’—B). 91-195° | 4-612° | 153-714° | 61-798° | 86-583° | 91 916° 91:089 | 4:402 | 153-612 | 61-936 | 86-687 | 91-676 90-866 | 4:385 | 153-545 | 61-954 | 86:481 | 91-591 91:048 | 4-325 | 153-781 | 62-163 | 86-723 | 91-618 91:162 | 4-194 | 153-229 | 62-095 | 86-968 | 91-134 90871 | 4-400 | 133-406 | 61:969 | 86-471 | 91-437 | 91-008 | 4:189 | 153°376 | 62-095 | 86-819 | 91-991 90:884 | 4:166 | 153-637 | 62°110 | 86-718 | 91-594 | 91-020 | 4:191 | 153-465 | 62-244 | 86-829 | 91-997 91-244 | 4-061 | 158-620 | 62-287 | 87-183 | 91-339 4 4 Means..| 91:'030 4,-260° 153 544 62 ‘095 86°769 | 91:449 ———— | ” nut 250 Mr. C. Spurge. On the Effect of Polish on the Table IV. we tan w. i? TL 24°9 0 -02470 107 ‘756. 1 25-7 0 -02493 107 “774 1 34-2 0-02741 107 °749 1 25:5 0 :02488 107°972 1 24°4 0 °02455 107 -662 1 36:8 0 :02816 107 -687 1 27-4 0 02543 107 °735 1 27-2 0 -02537 107 °873 L278 0°02555 107 °855 1 1455 0 °02168 107-953 1 20°8 0:02349 108-015 1 28°1 0 -02565 107 -805 Means.. 82655, 0 °02515 107 °819 Taking from Table III the mean values of R’—R, r’—7r, we have— sin 86°769 cos 2a = in OI 440 == () 99873. Thus = 1° 26:6’, and we obtain for the values of the quantities, which we are seeking in order to determine the nature of the polarised light, tan w = 0:02520, l= 107 3ig. Comparing these values with those formerly obtained which follow Table II, we see that the effect of polishing is to cause a small alteration of the ratio of the axes and in the inclination of the major axis of the ellipse. Thus the ratio of the axes has been changed from 0°03346 to 0:02520, while the inclination has been changed from 108:088° to 107°819°, an alteration of about 16’. These results also show that the reflected light is exceedingly nearly plane polarised. Again, the Tables III give for the subsidiary quantity p, _ tan 86°769 uy. P= tan 91-449 so that p = 116° 37’. — 0°44808, Cos The value of p obtained before polishing was— p =i iae | These values are not the same, but this has no bearing on the polishing, inasmuch as p is a constant of the instrument and is inde- pendent of the crystal. “ Reflexion of Light from Iceland Spar. 251 In order to test the truth of the results we have arrived at, a Nicol’s prism, the azimuth of which could be read off by a divided circle to 3’, was mounted on the side of the table opposite to that on which the elliptic analyser was, in such a position that, when the angle of incidence was the same as before, the light was reflected along the tube containing the Nicol. It was found that the light reflected from the surface could be reduced to a minimum but could never be completely eclipsed. The minimum was very small but quite per- ceptible. This might be due to the fact that the light was not homo- geneous. But further experiments showed that, even with orange and ruby glasses there was a perceptible minimum. Next the inci- dence was increased and diminished in succession by 5°, and the same result obtained. We, therefore, conclude as before, that the light was slightly elliptically polarised. VIII. Discussion of the Determination of the Retardation of the Quarter Wave Plate. We have now to inquire into the discrepancy of the values of p, which have been found before and after polishing, viz. :—p = 111° 14’ fad p = 116° 37’. Now, cos p is the ratio of the tangents of two angles, one of which is very nearly 90°. Consequently, a very small error in this last angle will produce a considerable change in the value of cosp. We therefore come to this conclusion, that it is not a good plan to deter- mine the instrumental constant p by reflexion from Iceland spar, because the light reflected is so slightly elliptically polarised. To determine more accurately the value of p, a steel plate was substi- tuted for the crystal. At first, white light was used as before, but the image was found to be strongly coloured. The difference in readings for blue and red rays was several degrees. After trying a spectroscope and coloured glasses, a ruby glass was selected as the best. Then the observations recorded in Table V were made. Table V.—Observations with a Steel Plate. Mean Temp. 17° C. 1. r’. sie heures Re 20 °468° 74.°705° 89° 296° 5 -297° 20 °515 74.°661 89 -082 4,°885 20°529 74, °334 88 °917 5 097 20 °495 74.°117 88 °978 5 °286 20 -692 74° 685 89 ‘160 5305 20-277 74.°135 89-034 5:190 20°520 74.°282 89 °214, 5 °635 20°527 74767 89 °235 5 °400 252 Mr. C. Spurge. On the Effect of Polish on the Table VI. a. tan aw. Cos p. p. i re) / fe) / 7) *SOr5 0°3184 0°14595 81 36 47 -296° 7 Ais)50 0°3195 0: 140638 Sl Wa5 46° 983 17 52-0 0°3223 0°14797 830 47 -007 yh eter fi) 0°3239 0° 15006 81 22 47 °132 17 46°5 0°3206 0 °14814 81 29 A7 °232 ihe Cs 0°3218 0:14768 lh 330) 47 °112 1 352-0 0 °3224 OPED Si 0 47° 424. i 385 0°3181 0°14999 81 22 47 °317 From Table V we may find with what accuracy we can work with the elliptic analyser. The greatest difference between the mean and a single observation is 0°003, so that the error of determination of tan a is less than a per- centage. The mean value of I is 47°188°, and the greatest error 0°236° or 14/. The mean value of pis 81° 29’, and the greatest error is some- what less than 26’. Let d be the space retardation measured in air for wave-length A, then— a Q7d/r. Thus the error in the determination of » expressed in wave-lengths is— ANS OP ha 2G.) fess od = 360 = “2T600 = BBT As in the experiments tana = 0°3209, this is very nearly the case in which the accuracy of the analyser has been determined by Pro- fessor Stokes. The present results agree well with his limits of aceuracy. ‘‘The mean error of single observations amounted to about ?° in the determination of the azimuth of the principal axis, about three or four thousandths in the ratio of the minor to the major axis, and a little more than a thousandth part of an undulation in the determina- tion of p.’’* . 7 We notice that in the mode of expressing p in degrees an error will be made more apparent, for the formula p = 27d/X\ shows that the space retardation is divided by the small quantity \. Thus, express- ing the difference 5° between the two sets of observations in wave- lengths, we find that the error of determination of p is only about 14 per cent. of a wave-length. * ‘Phil. Mag.,’ vol. 2, 1851. Reflexion of Light from Iceland Spar. 250 The value of p which has been determined is for red light, whereas the experiments made on the crystal face were performed with white light. It was not possible to determine p accurately for blue rays, as a blue glass absorbed too much light. We cannot, therefore, employ, the value of pas determined hy the steel plate to accurately correct the observations made with the crystal. Nevertheless, let us see what the effect of the substitution will be. : by gsi, (ti—= 7) We have cos 247 = Teeny tan sae and | SE reir a GH 2B, Since p is supposed known, eliminate the smaller quantity R'—R, and we find , Sitiay COs? 1) SIM py yee je |. CAR) This formula shows that if there be any change in the ratio of the axes there must be a change in the value of r’—r. Looking at the Tables I, III, we see there is such a change. Using the last written formula and the mean values of *’—r from Tables I, Til, we find that HO a natural face tan w = 0°03552, and for the polished face tan w = 0:02789. Thus, even when the value of p for red light as determined by the steel plate is used, we find that the numerical results indicate that the character of the change produced by polishing remains the same. In the ease of the natural face, taking 12 observations of r’—r from Table I, the greatest deviation from the mean is less than 9’, leading by formula A to a deviation from the mean of less than 5 per cent. In the case of the polished face, the greatest deviation will be, accord- ing to Table III, about 10 per cent. : The value of p has been determined for only one colour, and conse- quently we cannot calculate its value accurately for light of mean wave- length, so as to be able to compare the value of p obtained from the steel plate with the value of p obtained from observations with the erystal. Let us, however, examine in a general way what the effect of change of wave-length on the value of p 1s. Let ¢ be the thickness of the selenite plate, uz, u’, the ordinary and ‘extraordinary indices for a line « of the spectrum. 254 Mr. C. Spurge. On the Effect of Polish on the Qa Then Pz — Sc teh st, zt : 20 , and for a line y, pe StH ght y py _ Xz Py By Consequently, x ee Now X decreases from the lines A to EH, and varies by considerably over 30 per cent. The variations in the difference »—p’ are very much less if any analogy holds with Iceland spar and quartz, for which the variation is less than 4 per cent.* Both causes tend to in- crease p as the wave-length diminishes. Thus, somewhere about D the retardation is 90°, and will approximate to the value derived from Table I for white light, as we approach EH. This discussion shows us that while the steel plate affords a more accurate means of ‘determining p for light of given refrangibility, yet p is to a large extent a purely instrumental constant, such that its value has no effect on the character of the results, and, when we con- sider that white light was used in the previous experiments, the value of p determined by Tables I, III, would seem to be confirmed by the steel plate observations. We therefore accept the results of Tables I —IV as determining the alteration in the polarisation of the reflected light. IX. Statement of Results. The results of Tables I—IV are brought together in Table VII for the sake of future reference and comparison, so as to exhibit a synop- tical view of the final result up to this stage of the work. Table VII. tan w. i. Ist Angle. 2nd Angle. Before polishing ..| 0-03345 | 108-088 | 105 6 99 | 74 58 35 After polishing ...| 0°02517 | 107°819 | 105 5 37 | 74 58 44 Difference ....| —0°00828 | —16’ 8” —52 49 X. Variation of Surface State of a Polished Crystal with the Time. It is a point of importance to determine if the state of the surface of a polished crystal is so permanent that it does not alter with the * Rudberg, ‘ Poggendorff, Annalen,’ vol. 14, p. 45; Glazebrook, ‘ Phil. Trans.,’ 1879, Reflexion of Light from Iceland Spar. 255 time, for otherwise the experiments made would not have very great value unless the time elapsed since polishing were specified. I found that preceding experimenters had made investigations on this point in regard to a few bodies, and had come to the conclusion that the surface did not alter with the time. Thus Seebeck found such a re- sult for some glass experimented upon,* and Sir John Conroy has proved that in the case of metallic surfaces the surface state is a fairly permanent one, not being destroyed by contact with a liquid or a considerable amount of rubbing with a chamois leather.+ It there- fore naturally occurred to me to examine this question for Iceland spar. For this purpose a simple analyser consisting of a Nicol and a graduated circle was set up on the side of the table opposite to the elliptic analyser, and placed in such a position that the light could be reduced to a minimum. The observations taken are recorded in Table VIIT. Table VIII. No. of | Mean reading | Mean reading Mean of vis aRP readings. | of 1st vernier. | of 2nd vernier. verniers. Dec. 8-11.) 9°5C.| 40 Z1 10-9 201 20°5 | 111 15°7 dan, 20).,)-| 9°7 60 21 11°76 201 21°6 111 16°68 9°8 60 21 11:93 201 20°8 111 16°36 Thus there is in the period of six weeks no time variation of a polished surface, for the differences between the means are quite within the limits of experimental error. Also this result is confirmed by the general character of the observations made with the elliptic analyser, which often extended over some weeks, during which no change was noticed. XI. Variation of Surface State of a Polished Crystal with Change of Temperature. An attempt was made to secure greater accuracy by altering the arrangement of the parts of the elliptic analyser. For this purpose the screw fixing the vertical stem was loosened, and the circular rim rotated through two right angles about the stem as axis. The Nicol was unscrewed from its collar, and the cell containing the quarter wave plate from the disk. The quarter wave plate was now con- nected with the collar and the Nicol with the disk. In this mode of * © Poggendorff, Annalen,’ vol. 20. + ‘Roy. Soc. Proc.,’ vol. 31, 1881. 256 Mr. C. Spurge. On the Effect of Polish on the arrangement, therefore, the Nicol moves in azimuth, carrying the quarter wave plate with it, while the quarter wave plate has likewise an independent motion in azimuth. After taking 700 readings I became convinced that the accuracy of this mode of using the analyser was less than previously. 4 oo rg Proc. Roy. Soc. Vol.42. Pl. 3. AIR collected on the Roof of SCIENCE SCHOOLS SOUTH KENSINGTON MUSEUM. 1886. \ ie 301 5 205 0 SS ms 8 sO mgs = To — | ha ifr See May June Suby Aug* r 52025 | | Jes f x The black lines join the Experimental points. | va s = eee = = a The pecked lines jour the Averages for each month. | / \ : ail s ..... The dotted. lines jo the temperatures Wr centigrade A : — - 3 4 © degrees, observed on the occasion of each Experi - | | ye a / ‘ : il 6 \ / 3 / : fel | | A |e | = at ail E Waal ie a : . \ | | V r cS) be 4 i =| ¥ | 7 g — + —} | V oN aa 8 Li aa | es Hee Ne ete = ah) 7 WV een eae (ae SS = at 4 ee ee | = Sie —- - - iy & si | L Sate VWeat Newman & Co lith On Phosphonium Chloride. 283 April 21, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— T. “On Phosphonium Chloride.” By SIDNEY SKINNER, B.A., Scholar of Christ’s College, Cambridge. Communicated by Professor DEwaAr, F.R.S. Received March 28, 1887. At the close of an interesting paper in the ‘ Annales de Chimie,’ vol. 20, 1880, Ogier describes the preparation of the compound phosphonium chloride. When the two gases phosphine and hydro- chloric acid are mixed at 14° C. under atmospheric pressure they do not combine; but when the pressure is raised to 20 atmospheres small crystals of the compound PH,Cl form at the upper end of the tube. At 26° C. these crystals melt, and the liquid formed was shown by some later experiments of van’t Hoff (‘Deutsch. Chem. Gesell. Ber.,’ Jahrg. 18, p. 2088) to reach the critical state about 50°. This was the extent of our knowledge when the following experiments were begun with a view to examine more exactly this dissociable process, (1) in regard to its relations to temperature, volume, and pressure, and to those of the separate gases PH, and HCl; (2) in regard to the thermal changes involved in the formation of the compound. This paper deals with the first part of the research only, but owing to the interesting results which it contains there can be little hesitation in putting it forth. Hzperiments on Phosphoniwm Chloride. Phosphine was prepared by dropping strong potash solution on a mixture of broken glass and phosphonium iodide. After leaving the flask in which this operation was conducted the gas passed through a tube containing moist broken glass kept at the temperature of melting ice, and then through a drying tube of CaCl, and P,O,;. The gas was collected in tubes over mercury. The hydrochloric acid gas was prepared from strong sulphuric acid and ammonium chloride. To obtain a mixture of equal volumes of these two gases, a pipette VOL. XLII. : ¥ 284 Mr. 8. Skinner. [Apr. 21, was constructed so that it could be filled to a certain mark under atmospheric pressure and at the temperature of the room. This being filled alternately with PH, and HCl, was discharged into a large glass tube. In this way I prepared a mixture of equal volumes of the two gases. Part of this was delivered into a Cailletet tube which was set up in one of the iron bottles of a Cailletet pump; in the other bottle was placed a well tested air gauge. The temperature of the tube was maintained constant by a vapour jacket of acetone, and altered by varying the pressure under which the liquid boiled. Observations were then taken for isothermals. The following, as useful for the present purpose, are extracted from those readings; the whole mass of the gas used being 18°0 c.c. at 0° and 760 mm. Temp. - Saturated vol. Pressure. eames AD mar eis Sa. 11:6 atmospheres. ches Wilge cokgaeaaays 0 FOAMGICs = ci. se + ns 19°3 < TR as Pepes take 3 OEE SS y ACRE CU Sonor 27°3 ‘4 Pay ips tage ae CLE a ro ee 33°6 “ HRSG cera OO Teh naemtiy so 6° 39°1 56 Ose) sige te evs () 2D ak Maes ob, 2» 47 °2 5 ay ne er UMD ars 5 SO 85°3 ip The critical point of the liquid was observed at 48° C. and under 95 atmospheres. The temperature at which the crystals are formed under one atmosphere pressure is given as —30° by Ogier. The formation of these crystals is evidently a dissociable one, for when the pressure is removed they decompose into equal volumes of the separate gases. The question whether any chemical combination takes place before the appearance of crystals is one we shall discuss when considering the saturated volume curve of PH,Cl in comparison with those of its constituents. Haperiments on Phosphine. This gas, prepared and dried as before, was passed for some hours through a Cailletet tube from which the air had previously been displaced with carbonic acid gas. After careful sealing the tube was placed in the iron bottle, and liquid was readily obtained at the ordinary temperature under a pressure of about 30 atmospheres. The critical state was reached with this liquid at 54° and 70°5 atmospheres pressures ; so that it is easily observed when the tube is heated with acetone vapour. It is interesting to compare this critical point with that of the nitrogen analogue, ammonia, which does not reach the critical state till 130° and 115 atmospheres pressure. This 1887. | On Phosphonium Chloride. 285 is an unexpected result, as the substitution of a less volatile element has the effect of raising the critical temperature: thus for CO, critical temperature is 31:9° and for CS, 278°. I have also noticed the formation of a crystalline hydrate of phosphine when the gas is liquefied in the presence of water. The liquid gas floats on the surface of the water like benzene, and is apparently only slightly soluble. By suddenly increasing and decreasing the pressure the two liquids are mixed together, and oo a short time a mass of crystals is formed. The following table gives the results of measurements of the saturated volume, maximum pressure, and liquid volume at different temperatures. Temperature. gas Mee Liquid volume. Density of volume. pressure. the liquid. 4 €.C. atmospheres. C.C. 51 °4 oi ae 0-160 0 *402 AQ ° 4, 0°362 62° 4: 0°154, 0°417 44 4 0° 468 56 °1 0°137 0°469 39 °4: 0°553 50°8 0°128 0°502 29° 4: 0-744, 41°3 0°120 0°536 24:°6 0°851 37°71 0-118 0-545 18 °4: oe 32 °6 0°115 0-559 8°4 27 2 0-108 0 °595 2°4: 23°4 0°104 0°618 The numbers in the column headed density are calculated by dividing the whole mass in grams of the gas by the volume of the liquid in cubic centimetres. The mass of the gas was 0°06435 gram. The physical constants for hydrochloric acid gas used in the diagrams are calculated from Ansdell’s paper (‘Roy. Soc. Proc.,’ vol. 30, 1880). The mass of the gas* he used was 0°08531 gram; and therefore the proper reduction has been made so that the volumes in _ the diagram may be those occupied by the molecular mass of hydro- chlorice acid in milligrams. In the first diagram I have plotted for comparison the maximum pressure of the vapours at different temperatures both above and below zero. In the case of PH,Cl the curve is drawn from my own observations from the critical point to 7°; that point is joined by a dotted curve to the point corresponding to 1 atmosphere at —30°, at which temperature Ogier states that the crystals are formed under atmospheric pressure. The curve for HCl below zero is from numbers given by Faraday (‘ Phil. Trans.,’ 1846). The curve for PH, is from * Found by calculation from Ansdell’s data. ¥ 2 286 Mr. 8. Skinner. | Apr. 21, Fie. 1. of Measzrzneune Fressures. | | | | © oO ss Z » ~ & wt iw Q ™~ ~~ be ~N = j ® y . iq . ~ S ~ ex BS “ +20° +30° +40 Tenperatures tw degrees Cernligrade. my own observations, and would run alongside of that for HCl if continued below zero. The boiling point of PH; is given by Olszewski as —85°. At first sight it is evident that the form of the curve for PH,Cl is not a normal one, for if it were it would lie in the same direction as the other two. At all temperatures the pressure is much lower than that corresponding to a mixture of the two gases PH, and HCl, so that it is evident forces of chemical attraction are acting. From —30° to 10° the curve runs normally, so it appears that the gas probably consists wholly, from reasons we shall presently point out, of PH, and HCl molecules. Above 10° these two gases combine and the pressure necessary to deposit the crystals very rapidly increases. If the temperature be maintained constant the whole of the mixture is converted to the crystals of the compound under constant pressure by reducing the volume, just as a saturated vapour is converted into a liquid under similar conditions. At the temperature at which the crystals melt there should be an 1887.] On Phosphonium Chloride. 287 alteration in the direction of the curve, if the phenomenon of fusion is analogous in this case to that of melting ice. However, such an alteration can scarcely be seen in the diagram, but would doubtless be made apparent by very careful observations. ing 2. Dragram of Saturated Volumes Gade ASA / a w N\ S © S ~ Ne WG i) x > .) Crber ase Voli es L 15° 20° aise 35° 7 CUYIC'Ce Cures ttt degi tees Ceutt yt ade. In the second diagram I have plotted curves representing the saturated volumes at different temperatures. To make them com- parable it is necessary to take definite masses of the gases. I have therefore plotted the volumes corresponding to 70°5 mgrms. PH,Cl, 34 mgrms. PH,, and 36°5 mgrms. HC]. It will be observed that 288 On Phosphonium Chloride. [Apr. 21, about 10° the saturated volume of the mixture corresponds to the sum of that of its components, whilst about their critical points the volumes are approximately equal. This shows that at 10° we are dealing with a mixture of the two gases, whilst near the critical point the mixture has combined and the deposition of liquid takes place from gaseous PH,Cl. | The volumes which the liquids occupy near their critical points are very nearly equal. This may be shown to be the case in another way. It has been proved from van der Waals’ formula that the result of dividing the critical temperature in absolute degrees by the critical pressure gives a number proportional to the greatest volume a liquid can occupy (Dewar, ‘Phil. Mag.,’ vol. 18, 1884). Now in our case we have— eae T° C. P,. Te abs. Pp atmos PH,Cl. 48° 95 3°5 Ge ol See 54 70°5 4°6 ECs coe. pe eueee 52 86 3°7 If then 4°6 volumes of liquid phosphine near the critical tem- perature were brought in contact with 3°7 volumes of liquid HCl about the same temperature, combination would take place with condensation of volume to nearly one half. This is a case of combina- tion of liquids obeying a law very similar to Gay-Lussac’s law for the combination of gases under ordinary conditions of temperature and pressure. A symbolic representation of this combination would be :— PH, = HCl = “Pia Ou 1 vol, liquid + 1 vol. liquid = 1 vol. liquid. A close analogy evidently exists between the law of combination by volume of these liquids near their critical temperatures and Gay- Lussac’s law; whether other cases of such a law of combination will be found is a question which cannot yet be answered. Nevertheless the results in this paper appear to me to give answers to these two questions which Ogier states in his essay:—({1) Ce liquide est-il la combinaison méme ou un simple mélange des gaz liquéfiés ? C’est ce qu’il ne m’a pas été possible d’élucider; (2) Peut- étre le chlorhydrate d’hydrogéne phosphoré existe-t-il réellement a Vétat gazeux a une température moins basse. I hope to continue these experiments with a view to determine the heat of formation of this compound PH,Cl, and also to determine the 1887.] Electric Time-constant of a Circular Disk. 289 conditions of the formation and composition of the hydrate of phosphine. I must express my best thanks to Professor Dewar, F.RB.S., for his many kind and helpful suggestions, and also to the Master and Fellows of Christ’s College, who have permitted me to retain my scholarship during the continuance of this work. Il. “On the Principal Electric Time-constant of a Circular Disk.” By Horack Lamp, M.A., F.R.S., Professor of Pure Mathematics in the Owens College, Victoria University. Received March 29, 1887. The time-constant for currents of any normal type in a given con- ductor is the time in which free currents of that type fall to 1/e of their original strength. In strictness there are for any conductor an infinite series of time-constants, corresponding to the various normal types, but in such a case as that of a coil of wire one of these is very great in comparison with the rest, which belong to types in which the current is in opposite directions in different parts of a section of the wire. And in all cases the time-constant correspond- ing to the most persistent type which can be present under given circumstances is, of course, the one which is most important from an experimental point of view. A determination of the time-constants of a uniform circular disk would be of interest for two reasons: first, in relation to Arago’s rotations, which are entirely due to the greater or less persistence of currents once started in the disk; and, secondly, in connexion with Professor Hughes’s experiments with the induction balance, in which the disturbance produced in the field by the currents induced in metal disks (such as coins) was studied. Unfortunately, the mathematical problem thus suggested would seem to be difficult. Restricting our- selves, for simplicity, to cases where the currents flow in circles concentric with the disk, so that the problem is not complicated by the existence of an electric potential, then if ¢ be the current-function, the electric momentum at a distance r from the centre of the disk will be —dP/dr, where P is the potential of an imaginary distribution of matter of density ¢ over the disk. Hence, if p’ be the resistance per unit area, we have— | pois. thd, dP pene Dae MOL. as In any normal type, ¢ and P will vary as e~*’, and, therefore— i dp dP —— cet 2. dr dr’ (2) 290 Prof. H. Lamb. On the Principal [Apr. 21, or, in the case of uniform resistance— | pd = AP+O over the disk. In the absence of a rigorous solution of this problem (which seems: well worthy the attention of mathematicians), a good approximation to the principal time-constant may be obtained on the following principles :—* 1. An increase of resistance in any part of the disk will diminish the time-constant; and 2. If the time-constant be calculated on any arbitrary assumption as to the distribution of current, the result will be an wnder-estimate, and will, moreover, be a close approximation to the true value if the assumed law be not very wide of the mark, on account of the “‘ stationary’ property of the normal types. Some distributions of density ¢, and corresponding potentials P, convenient for our purpose, are obtained by considering the disk as a. limiting form of heterogeneous ellipsoid, in which the surfaces of equal density are similar and coaxialellipsoids.+ If the density at any point Q in the interior of the ellipsoid— be C—6)", where 6a, 0b, 0c are the semi-axes of the similar ellipsoid through Q, the corresponding potential at internal points will be— ae Cores Un Soe dk +k B+k C+k ” SIE PEDO" Putting a = 6b, and passing to the case of a disk, by putting c= 0, 2Cc = 1, we find that to the surface-density— s ntd ‘ ot T(n+1) a Qn+1 SS — — 5 3. t o= G-; A cos x dx x T(n+3) (1 mr (3.)£ corresponds, for points of the disk, the potential— eae BOE EN l ge NMTE dls ~ 2(n+1) “i! e+k) (+k) * See Rayleigh’s ‘Sound,’ §§ 88, 305, &c. + See Ferrers, ‘Quart. Journ. Math.,’ vol. 14, p. 1. { In the electrical application we must suppose n+ 3 >0. 1837.] Electric Time-constant of a Circular Disk. 291 n+1 i al "(1-5 sin?x ay 72a y 72 aes oO Pum A 2 2 . 4, | Tar * ( Cay es a) se in the usual notation of hypergeometric series. In the electrical problem, then, to a current-function of the form (3) corresponds the current-strength— dp _ vz pee (4) Aeieeatig ae we a) — — es —— 9 az dr a T(n+4)a and the electric momentum— = SLE (-m 4 2, =) ee ia: The assumption (3) will correspond accurately to a normal type for a non-uniform disk, provided the law of resistance be properly adjusted. For (2) is satisfied if—- p T(n+1) Gee le en es aed he -*) = 2dr ; (1—S sin x) sin’x dy 3 (ia = a F (-», 2 2, =) n= that is, p= ra) (Q-5 sin’) sin? x dy +(1—",) Mn ) 2 2\ n= po (—n, 4 2, 5) + ( Se eal nantes (ke). where po is the resistance at the centre; and the time-constant is— T(n+3 4) TIO pe nay, tae r 2) iH ~ P@+t) Dane he For n = 0, we have— pl = py (1—r3ja%)3, 720 | Zpy! Since p’ diminishes from the centre outwards, we see that 4°935a/p’ is: a superior limit for a disk of uniform resistance p’. 292 Prof. H. Lamb. On the Principal [Apr. 21, ered Koni, hor 2 fae Pp = 2 Po. USs sin?) sin*y dy, from which it appears that 3°142a/p’ is a superior limit for a uniform disk. Mor 9 == 1. ’ re) re a be Sie (1-25) + (1-5): : 2Q oe ee / Ce e e e e e e e This case is remarkable as giving a resistance nearly uniform over the disk, except close to the edge, where it rapidly increases. The second column in the following table gives the resistance at various distances from the centre; the third column, the corresponding thick- nesses in terms of the thickens at the centre, the material of the disk being supposed uniform. ra 0'/0’o. Thickness. 0 1°000 1°000 O-l 0°998 1 ‘002 0°2 0°990 1°010 0°3 0°978 1-023 0 °*4 0 ‘960 1:041 0°5 0:938 1-066 0°6 0°913 1°096 Or7 0 °886 1°129 0°8 0° 867 1°154 059 0:900 1:111 0°95 1°035 0-966 0°99 1 ‘878 0°532 1°00 0 0 The minimum value of p’ is 0'8660p)', corresponding to r/a = Denoting this minimum by p,’, we find from (11)— 7 = 2137. Pi 0:8165. This is an inferior limit to the value of + for a disk of uniform resistance p,’. 1887.] —-_ Electric Time-constant of a Circular Disk. 293 Some further information may be gathered from the second principle stated above. The electrokinetic energy of the system of currents defined by (3) is— dp dP us , Qer dd - a| de depo _ wa T(n+1) [- — »\n—3 ss Ry McG Oe hk te i) ae The integral T(—n+m).T@t+m) 72) fi, ToEDT@ | Farm 0-9 an T(—n+m)l(2+m) 1 es) - >" Bm FL) E(—n) FG 8) h(m+n+5) T(n+4 : = tee Pi Sree tS) _ Pmt) Qn+1) ~ P2Qn+2)0(n+1) _ ma VQn+l1) . | Hence T= . T(Qn+2) Ne a i alas (12.) If the disk be of uniform resistance p’, the dissipation is— “| (= : . 2rr dr : dr + feos W Tp’ T(n+1) Tera) T(n+4) | Introducing a time-factor e~‘7, and supposing that the system of currents is constrained to remain of the type (3) during the decay, we find on equating the rate of diminution of the energy to the dissipation— ria POn+2){(n+4)}?_ | p’ V(n)P(n+1)P(Qn+8 ipo eign °(1120)) y Any value of 7 obtained from this formula will be an inferior limit 294 Prof. H. Lamb. On the Principal | [Apr. 21, to the true value. The following table gives the values of 79'/a for different values‘of n:— DHE HE EEHOOCOOCO CORON HOMOMDUIMAH bo bo bo bo bo bo by by bo bo by bo ta Cee : OU oO "O51 It appears that the value (14) of 7 is a maximum for n = 0°9 about, and, hence, that the principal time-constant of a circular disk is not less than 2°26a/p’.. We have seen that the value of ¢ obtained by putting n = 1 in (3) must be a pretty fair representation of the most persistent type of free currents in a uniform disk, and the case of nm = 0°9 will not be materially different. The “stationary ’’ property already alluded to therefore warrants us in asserting that the value just given must be a close approximation to the truth. If 6 be the thickness, p the specific resistance of the material, we may write our result thus— , = 206e. « For a disk of copper [p = 1600 C.G.S.], a decimetre in radius, and 2°5 mm. in thickness, this gives 7 = 0°0035 sec. . Addendum.—April 11, 1887. In the above calculations it is assumed that the current-intensity is sensibly uniform throughout the thickness of the disk. This will be the case, at all events for a non-magnetisable substance, if the radius be a moderately large multiple of the thickness. To examine this point more closely, it will be sufficient to consider a simpler — problem in which all the circumstances can be calculated with exact-— ness. Let us suppose then that we have a system of free currents everywhere parallel to the axis of z in a stratum of conducting matter bounded by the planes y = +6/2. With the usual notation we shall have— 1887. | Electric Time-constant of a Circular Disk. 295 K=O, G: ==0; aH aH a= — 6= dy’ da? ie) I (=) In the spaces on each side of the stratum— a On dae dye i) whilst in the conductor itself— oH OH _y dx? dy? Ge pete The equation of electromotive force is— pw = ——— = dH, the time-factor, as before, being e~*’. Let us further assume that # enters into the value of H only through a factor sin mz. We shall then have, in the conductor— Geos ee, | where BP Aer NY pn 18 Ah ont Seared ae (hd? lon) e and in the external spaces— The solutions of these equations, appropriate to our present problem, are H = Deoos ky, and A= Der, respectively, the upper or lower sign being taken in the latter expres- sion according as y is positive or negative. At the surfaces of the conductor we must have— == na bi ==1b) when the accented letters relate to points just outside, the unac- cented to points just inside. These conditions give— 296 Electric Time-constant of a Circular Disk. [Apr. 21, kD.sin a = pmD' e788 |? cos we 2 2 ie — D’ e778 /2, - hd 2 OEE ae whence ké. tan oF pmo... . . Se If » = 1, as we have supposed, and mé is small, the principal root of this equation in ké is small, and the current-intensity, which varies as cosky, will be nearly uniform throughout the thickness. The equation (16) then gives— 1282 = Iméd—Am*s* 4+ &e., and therefore from (15)— 9 Pe or a (1-—4mé+&c.), _where p' = p/é. For the purpose of a rough comparison with our original problem we may suppose that 7/m is comparable with R, the radius of the disk. It follows that the effect of replacing the actual disk, of finite thickness, by an infinitely thin disk of the same con- ductivity (per unit area) is to increase the time-constant by the fraction 6/R of itself, about. In an tron plate, on the other hand, the current-intensity will fall off considerably from the median plane to the surface, unless the ratio 6/R be extremely small. For instance, if wmé = 7/2, or say’ 6/R = 1/2, the principal root of (16) is ké = 7/2, and the intensity at the surface is only 0°71 of its value in the median plane, although the thickness of the disk may perhaps not exceed one-thousandth of the radius. Again if, mé being still small, wmé is moderately large, we shall have ké = z, nearly, so that the current-intensity almost vanishes at the surface. In such a case— 7 = Arpl/k?p = 4ué*/zp, roughly. It will be seen that within certain limits (e.g., if « = 500 and the lateral dimensions be not more than about 100 times the thickness) this result is independent of the size and shape of the plate. Under these circumstances, the value of 7 for an iron plate (p = 10,000 C.G.S.) whose thickness is 2°5 mm. will be comparable with 0°008 sec. 1887.] Meiolania platyceps. Dynamical Principles. 297 III. “On Parts of the Skeleton of Metolania platyceps (Ow.).” By Sir RicHarD OWEN, K.C.B., F.R.S., &. Received March 29, 13877. (Abstract). The subjects of the present paper are additional fossil remains of Meiolania platyceps from Lord Howe’s Island, transmitted to the British Museum since the author’s previous paper on the subject. Additional cranial characters are defined and illustrated by drawings of more or less perfect specimens of the skull, of vertebra of the neck, trunk, and tail, of limb-bones, and portions of the dermal skeleton. The author sums up the affinities, deducible from the above parts of the skeleton, to the orders Chelonia and Sauria, with grounds for the conclusion that the genera Megalania and Meiolania are more nearly akin to the Saurian division of the class Reptilia, in which he proposes to refer those extinct genera to a sub-order called Ceratosawria. IV. “Some Applications of Dynamical Principles to Physical: Phenomena. Part II.” By J. J. THomson, M.A., F.RS., Fellow of Trinity College and Cavendish Professor of Experimental Physics in the University of Cambridge. Received March 31, 1887. (Abstract. ) This is a continuation of a paper with the same title published in the ‘ Phil. Trans.,’ 1885, Part II. In the first paper dynamical principles were applied to the subjects of electricity and magnetism, elasticity and heat, to establish relations between phenomena in these branches of physics. In this paper corresponding principles are applied to chemical and quasi-chemical processes such as evaporation, liquefaction, dissociation, chemical combination, and the like. Many of the results obtained in this paper have been or can be obtained by means of the Second Law of Thermodynamics, but one of the objects of the paper is to show that there are other ways of attacking such questions, and that in many cases such problems can be solved as readiiy by the direct use of dynamical principles as by the Second Law of Thermodynamics. A great deal has been written on the connexion between the Second Law of Thermodynamics and the principle of Least Action ; some of these investigations are criticised in the first part of the 298 Prof. J. J. Thomson. Some Applications of — [Apr. 21, paper. After this it is shown that for a collection of molecules in a steady state, the equation (which for ordinary dynamical systems is identical with the well-known Hamiltonian principle) is satisfied, where T and V are respectively the mean values of the kinetic and potential energies taken over unit time, and where the variation denoted by 6 is of the following kind. The coordinates fixing the configuration of any physical system, consisting according to the molecular theory of the constitution of bodies of an immense number of molecules, may be divided into two classes :-— (a.) Coordinates, which we may call molar, which fix the con- figuration of the system as a whole; and (b.) Molecular coordinates which fix the configuration of individual molecules. We have the power of changing the molar coordinates at our pleasure, but we have no control over the molecular coordinates. In the equation— é(T—V) = 0 only the molar coordinates are supposed to vary, all velocities remain- ing unchanged. Hence in applying this equation we need only consider those terms in T and V which involve the molar coordinates, and expressions for these terms for gases, liquids, and solids are given in the paper; the rest of the paper after these have been obtained consists of applications of the above equation. The density of a vapour in equilibrium with its own liquid is obtained as a function of the temperature, and the effect upon the density of such things as the curvature or electrification of the surface of the liquid is determined. The phenomenon of dissociation is next investigated, and an expression for the density of a dissociated gas obtained which agrees substantially in form with that given by Professor Willard Gibbs in his well-known paper on the “ EHquilibrium of Heterogeneous Sub- stances.” The effect of pressure upon the melting point of solids and the phenomena of liquefaction are then investigated, and the results obtained for the effect of pressure upon the solubility of salts are shown to agree with the results of Sorby’s experiments on this subject. The effect of capillarity upon solubility is investigated, and it is shown that if the surface-tension increases as the salt dissolves then capillarity tends to diminish the solubility, and vice versd. The question of chemical combination is then considered, par- 1887. ] Dynamical Principles to Physical Phenomena. 299 ticularly the results of what is called by the chemists “ mass-action,” of which a particular case is the division of a base between two acids. The general problem investigated is that in which we have four substances A, B, OC, D present, such that A by its action on B produces C and D, while C by its action on D produces Aand B. The relation between the quantities of A, B, C, D present when there is equilibrium is obtained and found to involve the temperature; when the temperature is constant it agrees in some cases with that given by Guldberg and Waage, though in others it differs in some important respects. Thus if &, 7, €,¢ be the number of molecules of A, B, C, D respectively, when there is equilibrium, @ the absolute temperature, H the amount of heat given out when the chemical process which results in the increase of & by unity takes place, and & a quantity which is the same for all substances, then it is proved that— Hf a Ce, ee where C is a constant; p,q, 7, s are quantities such that if (A) represents the molecule of A, with a similar notation for the other molecules, then the chemical reaction can be represented by the equation— piA}+q{B} = r{C} +s(Dj5. Thus if A, B, C, D be respectively sulphuric acid, sodium nitrate, nitric acid, and sodium sulphate, in which case the reaction is represented by— Then if the molecules of sodium nitrate and nitric acid be repre- sented by NaNO; and HNO,, =. oe a ang, s =k: If, however, the molecules of sodium nitrate and nitric acid are represented respectively by Na,N,O, and H,N.O,, then since the chemical reaction may be written— H,SO,+Na,N,0O, = H,N,0,+ Na,SO,, a a. r=l, ane SL. According to Guldberg and Waage the relation between §&, 9, { « a fy = kf; VOL. XLI. 300 _ Mr. C. Chree. [Apr. 21, this when the temperature is constant, agrees with the above expression ifp =q=r=s. ; We see that the state of equilibrium will vary rapidly with the temperature if H be large, that is, if the chemical process is attended by the evolution of a large quantity of heat. The effect of alterations in the external circumstances such as those which may be produced by ecapillarity, pressure, or electrifica- tion are investigated, and it is shown that anything giving rise to potential energy which increases as the chemical combination goes on tends to stop the combination. The last part of the paper is taken up with the consideration of irreversible effects such as those accompanying the passage of electric currents through metallic conductors or electrolytes. These are looked upon as the average of a large number of discontinuous phenomena which succeed each other with great rapidity. The ordinary electrical equations with the usual resistance terms in, represent on this view the average state of the system, but give no direct information about its state at any particular instant. It is shown that if we take this view we can apply dynamical principles to these irreversible effects, and the results of this application to the case of electrical resistance are given in the paper. V. “Conduction of Heat in Liquids.” By C. Cureg, B.A., King’s College, Cambridge. Communicated by Professor J. J. THomson, F.R.S. Received March 31, 1887. (Abstract. ) In this research the liquid layer through which the conduction takes place is of a moderate thickness, the object being to obtain results not open to the objections which can be raised against most previous methods, in which conduction has taken place through layers of very small thickness. Two similar forms of apparatus, differing chiefly in size, were employed, but from the larger apparatus few results were obtained, and to these little independent weight is assigned. The liquid was contained in a wooden tub, and heat was applied by pouring hot water into a metal dish supported so as to be im con- tact with the liquid surface. At a given depth was fixed a fine platinum wire, and the variation in its temperature was determined by observing the variation in its electrical resistance. By this means the temperature at a given depth in the liquid is determined for any instant subsequent to the application of heat. In applying the heat a given quantity of water, heated to a given 1387.] Conduction of Heat in Liquids. 301 temperature, was suddenly poured into the metal dish, and the time noted. In one set of experiments this water was after a given interval siphoned from the dish, in another set it was left undis- turbed. In either case the variation in the temperature of the platinum wire, as indicated by the change in its resistance, was determined by observations of the readings of a delicate galvano- meter, which was affected by the variation in an electrical current traversing the platinum wire. The galvanometer readings supplied data from which could be calculated the interval that elapsed after the application of heat before the temperature in the liquid surround- ing the platinum wire was rising fastest. An independent series of experiments gave the rate at which heat passed into each liquid from the dish. To calculate the conductivity a mathematical investigation is carried out, which leads to an equation connecting the conductivity, density, and specific heat of a liquid with the time elapsed after the application of heat at the surface before the heating at a given depth should be most rapid. Though this equation cannot be directly solved, solutions of a close degree of approximation cau be obtained. The density and specific heat being known, these solutions enable the conductivity to be calculated in absolute measure. The liquids examined were water, paraffin and turpentine oils, bisulphide of carbon, methylated spirit, and solutions of various strengths of sulphuric acid and water. In the case of paraffin oil, methylated spirit, and water, the two different methods were employed, and the results agreed fairly well. In the case of turpen- tine the water was never siphoned, and in the case of the remaining liquids the siphon was always used. It was found that the con- ductivity of the various sulphuric acid solutions, some of consider- able strength, differed very slightly from that of water, and thus there is a marked distinction between conducting powers for heat and for electricity. The presence of small impurities in the liquids, such as small quantities of salt, had no appreciable effect on the conductivity. The intervals that elapsed after the application of heat before the temperature at the given depth was rising fastest did not differ very largely for the various liquids. It was shortest for the bisulphide and longest for turpentine. Owing to the comparatively small variation in this interval the value of the conductivity depends largely on the product of the density into the specific heat, a quantity to which it is directly proportional. The values actually obtained are the following :—In those under column | the water was siphoned from the dish, in column 2 it was not. The units are centimetre and minute. 302 | - Presents. [| Apr. 21, Liquid Column 1 Column 2 NVABCE cs ecyec sccm ane epetione eee UOC). cea 0 ‘0815 Solution sulphuric acid, No. 1 0 U7o9 eee — uk, : No. 22. ° O70 Tot 7 eee — sy No.3... -0"°0 700" "seer — “ No. 4’. O°O77S) eee : a5 Methylated spirit’. 20). e. ss «. 003540 02%. ane 0 -0346 Bisulphide of carbon .......... 00320" eae —_— Pa Vatin sONl! oe oss creeinteede sees 002640 eae 0 0273 Purpentiae Ol)... sa. a Oe 0 0189 The temperature of the various experiments differed somewhat, but as a rule was a little under 20° C. The difference of temperature in the two series of experiments on water tends partly to explain the discrepancy in the above results, as the results of previous observers indicate a considerable rise in conductivity with the temperature. For water and the methylated spirit results of a confirmatory nature’ were obtained by the larger apparatus. The experiments were conducted in the Cavendish Laboratory. Presents, April 21, 1887. Transactions. Baltimore :—Jehns Hopkins University. Circulars. Vol. VI. No. 56. Ato. Baltimore 1887. The University. Brussels :—Société Royale Malacologique de Belgique. Procés- Verbal. August—December, 1886. 8vo. Bruzelles. The Society. Buckhurst Hill :—Hssex Field Club. The Essex Naturalist. No. 3. 8vo. Buckhurst Hill 1887. ‘The Club. London :—London Mathematical Society. Proceedings. Nos. 275- 282: 8vo. London 1887. The Society. Odontological Society. Transactions. Vol. XIX. No. 5. 8vo. London 1887. The Society. Photographic Society of Great Britain. Journal and Transactions. Vol. XI. No. 6. 8vo. London 1887. The Society. Royal Horticultural Society. Journal. Vol. VIII. 8vo. London 1887. The Society. Royal Institute of British Architects. Journal of Proceedings. Vol. III. No. 12. 4to. London 1887. The Institute. Newcastle :—North of England Institute of Mining and Mechanical Engineers. Transactions. Vol. XXXVI. Part 2. 8vo. New- castle 1887. The Institute. 1887.] Presents. 303 Transactions (continued). Parvis:—Ecole Normale Supérieure. Annales. Tome IV. Nos. 3-4, 4to. Paris 1887. The School. Société Philomathique. Bulletin. Série VII. Tome X. No. 4. 8vo. Paris 1886. The Society. Rome :—R. Accademia dei Lincei. Atti. (Classe di Scienze Fisiche.) Serie IV. Vol. I. 4to. Roma 1885; Ditto. (Classe di Scienze Morali.) Serie IV. Vol. I. 4to. Romu 1885. The Academy. Tokio :—Imperial University. Journal of the College of Science. Vol. I. Part I. 4to. Tokyo 1886. The University. Turin:—R. Accademia delle Scienze. Atti. Vol. XXII. Disp. 7-9. 8vo. Torino 1887. The Academy. Vienna :—K. Akademie der Wissenschaften. Anzeiger. Nr. VI- VIII. 8vo. [ Wien] 1887. The Academy. K. K. Geologische Reichsanstalt. Abhandlungen. Band XII. Nr. 4. 4to. Wien 1886; Jahrbuch. Band XXXVI. Heft 4. 8vo. Wien 1886; Verhandiungen. Jahrg. 1886. Nr. 13-18. Jahrg. 1887. Nr. 1. 8vo. Wien. The Institute. Journals. American Journal of Philology. Vol. VII. No. 4. 8vo. Baltimore 1886. The Hditor. Horological Journal. Vol. XXIX. No. 344. 8vo. London 1887. The Horological Institute. Kosmos, an Eclectic Monthly Journal. Vol. I. Nos. 1-2. 4to. San Francisco 1887. The Editor. Naturalist (The). No. 141. 8vo. London 1887. The Hditors. Revista do Observatorio. Anno II. Num. 3. 8vo. Rio de Janeiro 1887. The Observatory. Scientific News. Vol. I. No. 2. 4to. London 1887. The Editor. ole 304 Dr. E. Hull. Note on Dr. Hinde’s Paper (Apr. 28, April 28, 1887. Professor STOKES, D.C.L., President, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “Note on Dr. G. J. Hinde’s Paper ‘On Beds of Sponge- remains in the Lower and Upper Greensand of the South of England’ (‘ Philosophical Transactions,’ 1885, p. 403).” By Epwarp Hutt, LL.D., F.R.S., &c., Director of the Geological Survey of Ireland. Received March 17, 1887. In a valuable communication read before the Society in May, 1885, Dr. Hinde has given an account of the bands of siliceous material, generally in the form of “ chert,” found at intervals in the two Green- sand formations of the Cretaceous period throughout the south of England—clearly indicating the extent to which siliceous sponges contributed to the formation of the successive sea-beds of this period ; an extent to which, as the ‘Challenger’ soundings show, has its parallel in some parts of the ocean at the present day. In discussing the origin of the chert and chalcedonic bands in which the spicules are imbedded, or out of which they have been dis- solved, leaving cavities in their place, Dr. Hinde states his opinion that “There can scarcely be room for doubting that the beds and irregular masses of chert . . . have been derived from the silica of these sponge-remains; and from the same source has also originated the silica* which, in many of the deposits—more particularly in the Blackdown Hills—has replaced the shells and tests of the mollusca and other calcareous organisms.” He proceeds to say, “ The theory has, however, been advocated that the silica of the chert has been derived rather as a direct deposit of this mineral from solution in sea- water, than as the product of the decomposition of the siliceous struc- ture of the sponges. Thus Dr. Bowerbank held that the sponges imbedded in the chert of the Greensand possessed horny and not siliceous skeletons, and that the silica in the chert in which they were imbedded was attracted from the exterior medium by the animal matter, and not secreted from the living sponge. Professor T. Rupert Jones maintains the view that the silica of the chert is derived * The italics are not in the original. 1887. | on Sponge-remains in the Crensand 305 directly from sea-water; and similar opinions as to the origin of the chert bands in the Upper Carboniferous limestones of Ireland have been put forward by Messrs. Hull and Hardman, and by M. Renard,* with respect to the phthanites in rocks of the same age in Belgium. It is a significant fact, however, in connexion with the chert-beds of the Trish Upper Carboniferous strata that some have been discovered filled with sponge-spicules like the chert of the Hnglish Greensand, and this indicates a similar origin for the silica, and negatives the supposition of Professor Hull that it was deposited “from warm shallow water charged with silica in solution, in which chemical reactions would be at once set up, favoured and promoted by tidal and other currents.” I have taken pains to quote the entire passage in Dr. Hinde’s paper in order to avoid the possibility of misrepresentation; and I must confess my inability to understand the Seasguine of the author. He regards the sponge-spicules as “the source”’ of the silica, and by their decomposition in the presence of sea- water as having given origin to the beds of chert; but the question arises, from what source did the sponge-skeletons themselves derive the silica from which they were formed? This could not have been from repeated solution and re- construction, because by this process the supply of silica would have been used up. The statement, therefore, that ‘‘ the beds and irregular masses of chert have been derived solely from the silica of the sponge- remains instead of from that held in solution by the sea-waters them- selves” is altogether unintelligible. The real ‘‘source” of the silica is that small amount of this mineral which is always present in ocean waters ; from this source the sponge-structures have been derived by organic agency, and without that agency the silica would seldom be solidified. Sponge siliceous skeletons are in reality the result of the presence of silica in sea-water—not its cause. If there had been no soluble silica there had been no siliceous sponges. But I am only here concerned with a defence of the views arrived at, after full in- * Dr. Hinde, in referring to Prof. Renard’s Memoir (‘ Bulletin de 1’ Académie Royale de Belgique,’ vol. 46, 1878, p. 471), goes so far as to question the author’s determination of the nature of the “circular sections’? shown in one of the figures (fig. 2) accompanying the paper. The author identifies them as crinoid stems, Dr. Hinde suggests that they are really sponge-spicules ; a view that no one | so well acquainted with the Carboniferous Limestone as Professor Renard will for a moment admit. + Dr. Hinde does not mention his authority for the statement of the abundance of sponge-spicules in the Carboniferous Limestone of Ireland, and I suspect that he has in this case, as in that of the phthanites of Belgium, mistaken the sections of erinoids for those of sponge-structures. There is no doubt some difficulty in dis- tinguishing sections of sponge-spicules from ill-preserved segments of crinoid stems such as occur in chert; so that their identity must be determined by the forms which are prevalent in the ordinary limestones. 306 Dr. E. Hull. Note on Dr. Hinde’s Paper [Apr. 28,. vestigation by my colleague, Mr. Hardman, and myself,* and corrobo- rated by the independent investigations of M. Renard in Belgium ;+ and I wish to show how improbable it is that siliceous sponges could, by their dissolution, have taken any important part in the formation of the chert-beds of the Carboniferous Limestone either of Ireland or Belgium, or as far as I am aware of any other country. My argument will be based on the fact that the development of sponge-life in the seas of the Carboniferous period was insignificant, and quite inade- quate to account for the existence of bands and masses of chert, sometimes constituting almost a half or a third of the entire mass of the Upper Limestone.{ Let us now enquire what are the relative proportions of the genera — and species of siliceous sponge-structures to those of calcareous forms both in Carboniferous and Cretaceous strata—assuming that the genera ~ and species indicate to some extent the numerical development of these respective forms. In this comparison I shall omit from con- sideration the mollusca and molluscoidea—though in themselves very important, and altogether lime-forming organisms. In drawing up the following table (p. 307) I have availed myself of the lists published recently by Mr. Htheridge, F.R.S., which make the comparison simple and easy.§ The contrast of the non-molluscan fauna of the two periods will be at once apparent (1) in the enormous proportion of siliceous sponges in the Cretaceous as compared with those of the Carboniferous periods ; and (2) in the predominance of corals and crinoids in the Carbonife- rous period. The insignificant representation of siliceous sponge- structures in the Carboniferous seas as compared with the calcareous foraminifers, corals, and crinoids will also be apparent. As compared with the development of these forms in the Carboniferous period, it will be seen that the species of siliceous sponges might almost be counted on the fingers of the two hands; both in genera, species, and individuals they are quite unimportant as compared with the calca- reous organisms of that pericd, and totally inadequate to supply mate- rial for the formation of such beds of chert as are formed in the Carboniferous Limestone formation. The enormous predominance of the calcareous organisms in this formation is a fact which cannot be * “On the Nature and Origin of Beds of Chert of the Upper Carboniferous Limestone of Ireland.” ‘Scientific Transactions of the Royal Dublin Society,’ vol. 1, 1878. t+ “Recherches lithologiques sur les phthanites du calcaire carbonifére de Belgique.” Par M. A. Renard. ‘Bulletin de Académie Royale de Belgique,’ vol. 46, 1878. t As in the case of the Upper Limestone of Florence Court, near Enniskillen, altogether 400 feet thick, of which perhaps 150 are formed of chert-bands, inter- calated with those of limestone. § Phillips’ ‘Manual of Geology,’ Edit. 1885, Part II. | 1887. | on Sponge-remains in the Greensand. 307 Table showing the Genera and Species of Invertebrata, other than Mollusca, in the Carboniferous and Cretaceous Periods. Carboniferous. Cretaceous. Observations. Genera.| Species.| Genera.| Species. Siliceous sponges 6 12 74 162 There isa slight Protozoa Calcareous te 2 2 13 50 | uncertainty re- IGMATMIMITELA 6 2. eae es sre 15 43 39 171 | garding the nu- HEUVGTOZO cc's) se ss os nee +s 2 3 P P merical propor- PREEIIOZ OAS «6 5. . 11 34, z 14 | the Carboniferous (OR TISTIE ICSE NAG) An re ns one ee 28 13\* 4.0 110 | period. Toll) iG Nee ee sila is ayes “6 ofr 59 114 Total Siliceous sponges 6 12 74: 162 Calcareous organisms] 121 514 240 736 * Chiefly Entomostraca of the Upper Carboniferous stage. disputed by those who have had opportunities of studying its charac- ters, either in the north of England, in Ireland, or in Belgium, where whole beds may be observed composed almost entirely of crinoid stems and corals; while the microscope generally reveals other calcareous forms, such as those of foraminifera, which are invisible to the naked eye, or under the lens. If, then, these original calcareous structures have become silicified, whence could the silica have been derived if not from the circumambient waters of the ocean under certain special and favourable conditions of temperature ? In his paper on the origin of the beds and nodules of chert (phtha- nite) in the Carboniferous limestone of Belgium, M. Renard expressly identifies crinoid structures, not only in circular disks of the cross- section of ithe stems or ossicles, but in the more solid and structure- less masses of the chert when treated with acid ;* and he expressly states that the silicification has supervened in the ease of an originally calcareous rock-compound chiefly of foraminifera, crinoids, and corals; and, as Dr. Hinde himself admits, M. Renard distinctly states that there is no evidence that the infiltered silex into the limestone is derived from the decomposition of sponge-spicules or frustules of diatoms. Surely such a statement from so competent an observer is entitled to more consideration than that accorded to it by Dr. Hinde, * Loe. cit., p. 492. \ + Tbid., p. 196. 308 Mr. E. T. Hardman. [Apr. 28, who considers that M. Renard has mistaken sponge-spicules for crinoid stems.* | In conclusion, it may be asked what is the evidence which Dr. Hinde can assign for his statement—that the silica of Carboniferous chert has been derived from sponge-spicules ? Absolutely none, except a fanciful analogy between these peculiar masses and the sponge-beds of the Cretaceous formation. On the other hand, it has been shown that no such analogy exists, inasmuch as there was a marked contrast between the organic beings in the waters of the Carboniferous seas as compared with those of the Cretaceous period. In the former siliceous sponges were exceedingly rare; in the latter they abounded; so that, whatever part they may have played in the construction of the Creta- ceous bands of chert, it is clear they could have taken no important part in the formation of the chert-bands of the Carboniferous Lime- stone. The relative weight of opinion as expressed in the papers dealing specially with this subject must be left to individual judgment ; in forming this judgment, however, it will not be overlooked that identical conclusions have been arrived at regarding the mode of formation of the Carboniferous chert-bands by two sets of observers working independently, one in Ireland the other in Belgium, almost at the same period, and both using chemical and microscopical appliances. I trust, therefore, that I have succeeded in showing that there are good grounds for the opinion of those who consider that the beds and nodules of siliceous material in the Carboniferous Limestone have been formed by a direct replacement of original calcareous matter of the limestone itself by silica held in solution in the ocean-waters, and that, consequently, Dr. Hinde is not justified in referring them for their origin to sponge-structures. II. “ Note on Professor Hull’s Paper.” By Epwarp T. HARDMAN, of the Geological Survey of Ireland. Communicated by EK. Huu, F.R.S. Received April 5, 1887. Dr. Alleyne Nicholson, a paleontologist of no small repute, refers to this subject in his work on the ‘Ancient Life History of the Harth,’ p. 34. He considers that the silica which has surrounded and infiltrated the fossils which flint contains, must have been deposited “from sea-water in a gelatinous condition, and subsequently have * Dr. Hinde’s words are: “There are shown, however, in one of the figures (fig. 2) accompanying M. Renard’s paper, circular sections which more nearly resemble those of sponge-spicules than of crinoid stems, to which they are assigned.” Note, loc. cit., p. 433. 1887. ] Note on Professor Hull’s Paper. 309 hardened,” Also that “the formation of flint may therefore be regarded as due to the separation of silica from sea-water, and its deposition round some organic body in a state of chemical change or decay.” This is essentially the theory I advanced in our joint paper, and that independently arrived at by the Abbé Renard, namely, pseudo- morphism. Dr. Nicholson says further: ‘It has been asserted that the flints of the chalk are merely fossil sponges. No explanation of the origin of flint, however, can be satisfactory, unless it embraces the origin of chert in almost all limestones from the Silurian upwards, as well as the common phenomenon of the silicification of organic bodies (such as corals and shells) which are known with certainty to have been originally calcareous.” In our paper the prevalence and thickness of the chert of the Carboniferous Limestone of Ireland is referred to. I have since had an opportunity of seeing the siliceous alteration of limestone on a very large scale, and in different formations, in the tropical region of Western Australia, when engaged there as Government Geologist. It is seen in the Lower Silurian, Carboniferous, and Upper Tertiary deposits. The transition from the limestones into chert, flint, and calcedony, is clearly visible in many places where these minerals form ranges often miles in extent, and where the thickness of the flinty material occasionally reaches 300 feet. It is curious that these flint beds nearly always form the capping of the hills, but that they are of the same formation as the under- lying limestone is proved by the gradual passage of that rock into flmt; and where fossils occur in the limestone similar fossils are observed in the flint, until they become obliterated towards the summit.* J am inclined to attribute this to the action of highly- heated rain-water since the rocks have been deposited. In the warm season—which is also the rainy season, from about November to March—the rocks become intensely heated, and consequently, also the water lying in pools and cavities. J have been assured by settlers who have had to wade through flooded country, that at such times they could hardly endure the heat of the water, and I have experienced this to a slight extent myself. It is certain that under these circumstances silica would be more largely dissolved from one part, and more quickly deposited in another portion of the same rock; it is in fact on similar reasoning—the influence of sunlight and heat—that Professor Martin Duncan, F.R.S., explains the silicification of the West Indian Miocene Corals. * See ‘Report on the Geology of the Kimberley District, W. Australia.’ E. T. Hardman. Perth, W. A., 1885. P. 18. 310 Mr. O. Thomas. [Apr. 28, Whether it be heated rain-water, or heated sea-water containing silica, the principle of the transmutation is the same. These siliceous beds are found, not only in the marine Silurian (and possibly older) beds of tropical Australia, in which sponges are comparatively rare, and in the Carboniferous rocks, but also in a fresh-water deposit which caps a hill south of Mount Elder on the Ord River, and about 500 feet above the level of the country, showing that it must at one time have been the bed of a very extensive lake. The upper beds are white limestone merging upwards as usual into flint, calcedony, and green agates. These are 50 feet thick, and all abound in a fossil, Planorbis, as determined by Professor McCoy, of Melbourne University, who named it as a new species, Planorbis Hardmani. His decision was confirmed by R. Etheridge, Junr., and Dr. Woodward, and the specimens are at present in the Museum at South Kensington. This rock is simply one mass of Planorbis shells all highly silicified. I can hardly conceive that it was formed from sponge spicules, especially as according to Hrnst Haeckel (‘History of Creation,’ p- 139) the main class of the Sponges lives in the sea, with the single exception of the green fresh-water Sponge (Spongilia). It is not probable then that these organisms would have existed in these regions in sufficient numbers to form a rock 50 feet thick and over two miles square at present. We have therefore examples at both ends of the scale in this one country showing how improbable is the Sponge theory of chert. III. “On the Homologies and Succession of the Teeth in the Dasyuride, with an Attempt to trace the History of the Evolution of Mammalian Teeth in general.” By OLDFIELD THomas, British Museum (Natural History). Communi- cated by Dr. ALBERT GUNTHER, F'.R.S. Received April 4, 1887.. | (Abstract. ) The true homologies of the different teeth in the Marsupialia, and especially in the Dasyuride, have long been in a state of confusion, largely owing to their perplexing superficial resemblances to the teeth of the Carnivora and other Placentals, and to the incorrect homo- logies thereon founded. This confusion has been chiefly in regard to the premolars, of which some members of the family have two, others three, while generalised Placentals have four, and it is therefore necessary to prove which teeth have been successively lost in order to find out the correct homologies of the remainder. 1887.] On the Teeth of the Dasyuride. dil Firstly, as to which of the three premolars of such genera as Thylacinus and Phascologale have been lost in Dasyurus and Sarco- philus, each with only two—a study of the different members of the genus Phascologale shows that, judging by the great variability in size of the last premolar or pm.‘ of the typical mammalian dentition,* which is sometimes even altogether aborted, it is this tooth that is the one lost in Dasywrus and Sarcophilus, the total loss of the changing tooth naturally accounting for the non-discovery of a tooth-change in these genera. ' Next, since the original number of premolars was clearly four in the Marsupials as well as in the Placentals, it was necessary to find out which of these had disappeared \in the ordinary three-toothed genera of the Polyprotodonts, and this has been able to be done by the fortunate discovery of a specimen of Phascologale in which there are four premolars on one side, the additional tooth being inserted between the ordinary first and second premolars. The missing pre- molar is therefore pm.*, as shown both by this instance and by the relative positions of the teeth in other Polyprotodonts, the resulting premolar formula of Phascologale and Thylacinus being P.M. ped : ) - = LO a0 + 1 Se The milk dentition in several of the Dasywride is then described, among others that of the Purbeck Mesozoic Marsupial 7’riacanthodon serrula (Owen), which is proved to have, as had been suggested by Professors Owen and Flower, a milk dentition identical with that of the modern Marsupials. An attempt is then made to trace out the history of the evolution of mammalian teeth in general, and as a preliminary it is insisted (1) that the rudimentary tooth-change of the Marsupials is not a remnant of a fuller one, but a low and early stage in the development of com- plete diphyodontism, a stage out of which the Hutheria have long ago passed ; and (2) that, as maintained by Professor Flower, the milk teeth are the superadded and not the primary set. It is then suggested that the process by which a milk tooth was deve- loped consisted of two stages, firstly, a preliminary retardation of the permanent tooth, and secondly, of the development of a temporary tooth in the gap in the tooth-row caused thereby; the retardation in the first case being useful for packing purposes in a large-toothed and of Dasyurus and Sarcophilus P.M. * Although the homology of this tooth with the pm.‘ of Placentals, first made out by Professor Flower, has been called in question, there can be no doubt that it is entirely correct. + This method of writing dental formule is recommended as showing not only the total number, but the homologies of the teeth, each of which has its own number in the series. 312 Dr. L. C. Wooldridge. [Apr. 28, animal, while in a small-toothed form the same retardation, if present by inheritance, would cause a more or less disadvantageous gap, best filled by the assumption of a milk tooth. The first stage, or stage of retardation, appears to be still repre- sented in the anterior upper incisors of many Polyprotodont Marsupials, and it is therefore believed that these teeth now represent the stage at which the ancestors of the Marsupials and Hutheria diverged from one another, a stage at which the further development of milk incisors was just commencing. : Following out this idea, it is shown how easily the transition from the Metatherian to the Hutherian stage of tooth-change may have taken place, a transition by the help of which a complete series of diagrams can be drawn up, following the history of each individual tooth, from the dentition of the earliest Mammals, homodont and monophyodont, as no doubt the unmodified Prototheria were, down to the varied forms of dentition, heterodont and diphyodont, existing at the present day. All the orders of Mammalia fall easily enough into their places in the main line of this scheme with one exception, namely, the Edentata, in whose case the evidence all tends to prove the correct- ness of Professor Parker’s suggestion as to their nearly direct derivation from the Prototheria, a suggestion that the characters of their teeth most fully support. On the same principles, therefore, as the main Proto-meta-eutherian line of tooth development is drawn up, a side branch, for which the name “‘ Paratherian ” is suggested, is made for the Edentates. Within that branch very little heterodontism has ever been developed, but otherwise the changes, except in the case of the as yet inexplicable dentition of Orycteropus have been of the same nature as those in the main line, the superaddition of a milk set of teeth in Vatusia being, as in the Meta- and Hu-theria, the last and most highly specialised development. IV. “Note on Protection in Anthrax.” By L. C. WooLDRIDGE, M.D., D.Sc., Demonstrator of Physiology, Guy’s Hospital. Communicated by E. KuEIN, M.D., F.B.S. Received April 16, 1887. Hitherto in the few cases in which protection against zymotic disease has been found possible, it has been effected by the communi- cation to the animal of a modified form of the disease against which protection is sought. I have succeeded in protecting rabbits from anthrax by an alto- gether different process, and although this is scarcely, at present, of practical utility, it may perbaps be found to be of some interest as 1887.] Note on Protection in Anthrax. 313 regards the general nature of protection in this and other diseases depending on micro-organisms. _ I use as a culture fluid for the anthrax bacillus a solution of a proteid body which is obtained from the testis and from the thymus gland. Ihave described this substance to the Society on a previous occasion,* so that I need not repeat the description of the process used in its preparation. The proteid substance is dissolved in dilate alkali and the solution sterilised by repeated boiling. It is then inoculated with anthrax and maintained at 37° C. for two or three days. The growth is generally not very abundant, and at the end of the period mentioned is removed from the culture fiuid by filtration. A small quantity of the filtered culture fluid is injected into the circula- tion of a rabbit, and it is then found that the animal will not take anthrax. A subcutaneous inoculation of extremely virulent anthrax blood made at the time of the injection of the protecting fluid, and two sub- sequent inoculations at intervals of five and ten days, remain entirely without effect. The animals used as a contro] invariably die. Four rabbits have been protected in this way. If the anthrax grown in the fluid be inoculated it either kills or it has no effect. It does not protect in the slightest degree. The injection of the culture fluid in which no anthrax has grown is without effect. The animals die as usual when inoculated. The injection of the fluid itself causes no ill symptoms whether anthrax has grown in it or not. If other albuminous fluids, e.g., blood-serum, be used as a culture medium and the filtered culture fluid be injected, it exerts no pro- tection. It may be fairly concluded that the growth of the anthrax bacillus in the special culture fluids used in these experiments gives rise to a substance which when injected into the organism protects against an immediate and subsequent attacks of anthrax. - Itswould obviously be of very great advantage if some such method as this could be used for the zymotic diseases affecting man for which no protective inoculation in the ordinary sense, appears possible. Iam indebted to the Medical Officer to the Local Government Board for permission to publish this short account of these experiments, the full description of which will appear in his report. I must also express my thanks to Dr. Klein, F.R.S., for kindly supplying me with many anthrax cultivations. * L. C. Wooldridge, “ Intravascular Clotting,” ‘ Roy. Soc. Proc.,’ 1886. 314 Presents. | [Apr. 28, Note added April 27th. The following experiments give additional weight to the previously described results. _ In the one case the anthrax grew with very great rapidity in the culture fluid, and the clear filtrate contained but a very small quantity of proteid matter. Forty cubic centimetres of this fluid was injected into a rabbit, and the rabbit immediately inoculated in the ear with virulent anthrax blood; in two days there was very marked oedema at the seat of inoculation, which increased to an enormous extent during the next few days, and then gradually subsided. The rabbit is now perfectly well, twenty-four days after the inoculation. In the second case the growth of anthrax had been very slight; 20 c.c. of the filtered fluid was injected, and the animal immediately inoculated in the leg with virulent anthrax blood. In three days there was marked cedema at the seat of inoculation. This spread up the leg to the back, so that there was enormous oedema occupying nearly the whole posterior part of the animal; this persisted for ten days, and then gradually subsided. The animal is quite well, twenty- eight days after inoculation. These cases are of interest, since they are obviously instances of partial protection. The animals are still affected by anthrax, but it is only as a severe local affection, and does not kill them. Presents, April 28th, 1887. Transactions. ‘ Baltimore :—Johns Hopkins University. Studies (Historical and Political Science). Series V. No. 4. 8vo. Baltimore 1887. The University. Breslau :—Schlesische Gesellschaft fiir Vateriandische Cultur. 63. Jahres-Bericht. 1885. 8vo. Breslau 1886 ; [ with] Rhizodendron Oppoliense, Gépp. Beschrieben von Dr. K. Gustav Stinzel. (Hrganzungsheft.) 8vo. Breslau 1886. The Society. Cambridge, Mass.:—Harvard College. Museum of Comparative Zoology. Bulletin. Vol. XIII. No. 3. 8vo. Cambridge 1887. ; The Museum. Edinburgh :—Royal Scottish Society of Arts. Transactions. Vol. XI. Part 4. 8vo. Edinburgh 1887. The Society. Gloucester :—Cotteswold Naturalists’ Field Club. Proceedings. 1885-86. 8vo. Gloucester [1887 |. The Club. London :—Royal Microscopical Society. Journal. December, 1886, and April, 1887. 8vo. London 1886-87. The Society. 1887. ] Presents. 315 Manchester :—Geological Society. Transactions. Vol. XIX. Parts 6-7. 8vo. Manchester 1887. The Society. New York:—American Geographical Society. Bulletin. Vol. XIX. No. 1. 8vo. New York 1887. The Society. Stockholm :—Kongl. Vetenskaps Akademie. Ofversigt. Are. 4A, No. 2. 8vo. Stockholm 1887. The Academy. Ziirich :—Schweizerisches Polytechnikum. Verzeichniss der Biblio- thek. 8vo. Zurich 1887. Prof. R. Wolf. ‘Observations and Reports. Chemnitz :—Konigl. Sachs. Meteorologisches Institut. Jahrbuch. 1885. 4to. Chemnitz 1886. The Institute. Liverpool :—Free Public Library. Thirty-fourth Annual Report. 8vo. Liverpool 1887. The Committee. London:—Royal Gardens, Kew. Bulletin of Miscellaneous Infor- mation. No. 3. 8vo. London 1887. The Director. Tiflis :— Physikalisches Observatorium. Meteorologische Beobach- tungen, 1885. 8vo. Tiflis 1886. The Observatory. Vienna:— K. K. Universitats-Sternwarte. Annalen. Band IV. Jahrgang 1884. 4to. Wien 1886. The Observatory. Washington :—Smithsonian Institution. Report. 1884. Part 2. 8vo. Washington 1885. The Institution. U.S. Coast and Geodetic Survey. Report. 1885. Parts 1-2. 8vo. Washington 1886, The Survey. U.S. Geological Survey. Bulletin. Nos. 30-33. 8vo. Washington 1886; Monographs. Vol. XI. 4to. Washington 1885. The Survey. VOL. XL. 2 dw 316 Rev. S. i Pemy. On the [May 3, May 5, 1887. Professor G. G. STOKES, D.C:L., President, in #he Ohaee The Presents received were laid on the table, and thanks ordered for them. In pursuance of the Statutes the names of the Candidates recom- mended for election into the Society were read from the Chair as follows :— Buchanan, John Young, M.A. King, George, M.B. Cash, John Theodore, M.D. | Kirk, Sir John, M.D. Douglass, Sir James Nicholas, | Lodge, Prof. Oliver Joseph, D.Sc. M.I.C.H. Milne, Prof. John, F.G.S. . | Ewing, Prof. James Alfred, B. Se. | Pickard-Cambridge, Rev. Cera, Forbes, Prof. George, M.A. vius, M.A. Gowers, William Richard, M.D. Snelus, George James, F.C. * Kennedy, Prof. Alexander. B. W., | Walsingham, Thomas, Lord. . M.1.C.H. Whitaker, William, B.A. - The following Papers were read :— I. “Report of the Observations of the Total Solar Eclipse of August 29, 1886, made at Carriacou.” By the Rev. 8. J. Perry, §.J., F.R.S.. Recered Apml 5, 183% (Abstract.) Carriacou is a small island situated about twenty miles to the north of the island of Grenada, the chief of the Windward group, and furnished an excellent site for the observation of the last solar eclipse. Most of the observers sent by the Eclipse Committee of the Royal Society to the West Indies in August of last year remained at Grenada, or on the small islands in its immediate vicinity, whilst Mr. Maunder and myself occupied the more distant northern station, where the totality was slightly diminished in duration. The work proposed for Mr. Maunder was to secure a series of — photographs of the corona, with exposures of 40s. and under, and also to obtain two photographs of the spectrum of the corona with the longest exposures possible. The coronal pictures were successful, and they are at present in the hands of Mr. Wesley, Assistant Secretary of ef oo rie ofl AB ata ¥ 1887.) Total Solar Eclipse of August 29, 1886. 317 the Royal Astronomical Society. The results of his careful examina- tion, and of the collation of this with other eclipse photographs, will form the subject of a later communication. The spectroscopic cameras mounted on the same equatorial framework failed to give any useful result. i The instrument used by myself was a 54-inch equatorial, by Alvan Clark, with a Rowland grating 14,438 lines to the inch, and the work assigned by the Committee was an examination of the spectrum of the inner corona immediately before and after totality, and a search for the carbon bands during totality. J was assisted by Sub-Lieutenant Helby, of H.M.S. “ ne hawk,” who pointed the slit of the spec- troscope, whilst may undivided attention was given to the bright lines in the field of view of the small observing telescope. The object glass cast a most perfect picture of the corona on the white enamelled cap of the slit plate, so there could have been no difficulty in directing the slit to any assigned position. In the search during totality for the carbon bands « and #, which should have been well within the field of view, extending as it did from wave-length 5600 to considerably beyond 6, the radial slit was placed near the solar equator, at distances from the moon’s limb vary- ing from 0:1 to 0°5 of a solar diameter, and was then removed to one of the sun’s poles, and placed tangentially at successive distances as before. In none of these positions could I detect the slightest trace of the carbon bands. The conclusion indicated by these observations seems to be that the vapour of carbon, if present in 1886, was not of ‘sufficient intensity to make an appreciable impression on the retina. ‘The dispersion was considerable, as I was using -the second order of spectrum with a power of about 4, but the fainter lines in the solar ‘spectrum, and the coronal lines when seen, were so distinct, that I scarcely think the dispersion could have been excessive. The observations both before and after totality were greatly inter- fered with by the clouds and heavy rain, but although rain fell within a few minutes from the beginning, and also very soon after totality, the sun seemed perfectly clear during the whole of the totality itself. As soon as the sun broke through the clouds and became visible on the slit of the spectroscope, inewtaviont Helby placed the slit at the centre of the rapidly decreasing crescent, and the first line that’ I detected was 1474 K, which ez iended to a distance of perhaps: 8’ from the limb. Almost at the’same instant I saw a mass of lines of ‘unequal length situated on the less refrangible side of b, but in close proximity to it. Their number I betinviaed at about 15, but I could form no idea of their relative intensities. This observation seems to favour the view that the absorption producing the Fraunhofer lines takes place in successive layers of the solar atmosphere, and not in any one layer exclusively, Within 20s. from the end of totality, thé 242 play Prof. T. G. Bonney. On the [May 5, radial slit being as near as possible to the point of reappearance, the whole field was crowded with bright lines, fifty or more being visible in the short space between wave-length 56CO and 6. I noticed no difference in the length of these lines. Clouds and rain soon put an end to all chance of further observations. , Interesting sketches were made during totality of the outer streamers by Captain Masterman and Mr. Osborn, of H.MS. “ Bullfrog,” who both used the circular disks arranged so as to cover the brighter portions of the inner corona. The instantaneous view that I obtained of the corona, most exquisitely defined on the white cap of the spectroscope, and the rapid glance I took with an excellent linocular, confirm the positions of the two principal rays drawn by Captain Masterman, but I ebserved at the same time a shorter ray between the two, which appears otherwise to have escaped detection, and I noticed the leaf-shaped.curvature of the ray in the north-west. The darkness was never much less than that of a fair moonlight night. Il. “Note on the Microscopic Structure of Rock Specimens from three Peaks in the Caucasus.” By T. G. BONNEY, D.Sc., LL.D., F.R.8., Professor of Geology in University — College, London. Received April 5, 1887. Although our knowledge of the petrology of the Caucasus has been considerably augmented of late years through the labours of Abich, Favre, Tschermak, and others, so much ground still remains un- trodden among its mountain peaks that hardly any specimen can be entirely without interest. Those described in the present note have come from the following localities:—(1) The summit of Tau Tetnuld; (2) rocks from the upper part of Guluku; (3) the summit of Elbruz. The specimens from Tau Tetnuld and Guluku were collected by Mr. W. F. Donkin, during his expedition in company with Mr. Clinton Dent in the summer of 1886, and to the former I am indebted for the following note on the localities. : “Tau Tetnuld is one of the peaks of the central Caucasian chain, in the great Koschtan-Tau group which lies about midway between Elbruz to the N.W., and Kasbek to the E.S8.E. From Koschtan-Tau the main ridge forming the watershed runs somewhat north of west, dropping gradually in height; but for some three or four miles forming a magnificent wall on the northern side, covered with a succession of steep snow-slopes and hanging glaciers. A long portion of this ridge, including three more or less well-marked elevations, is called Djanga; the next elevation on the ridge—a much more obvious one, forming indeed a symmetrical snow pyramid—is Tau Tetnuld. 188%.] Structure of Rocks from the Caucasus. dl9 From the north it appears to have a sharp conical summit, but it is really wedge-shaped. Further westwards the ridge falls continuonsly, a few rocky peaks protruding from it, to a well-marked snow col. The drainage from the whole of this vast wall, from Koschtan-Tau to the col inclusive, collects in a basin, and flows northwards as the Bezingi glacier. The glacier is remarkably level and free from ice-falls, and appears to start almost direct from the foot of the wall, with but little sloping névé. Its course is-soon narrowed to a channel of some 1200 yards wide by spurs from the high ridges running northwards on either side: Onithe west the ridge does not attain any great elevation, but on the:east the glacier is bounded by a group of mountains culminating in the great rock-mass of Guluku. This group is completely separated from the Koschtan-Tau chain by the glacier basin above mentioned.. Guluku itself is granitic in character, but the lower and surrounding peaks and ridges are schistose and shaly, in parts. exactly like the Ober- and Unter- Rothhorn on the north side of the Findelen glacier.* The upper rocks of Guluku are grey in colour and look very, like granite from some distance below; then comes a belt of whiter rocks (A), and below that a well-marked red belt (B); both these belts are con- tinuous and nearly horizontal for a long way roundithe southern side of the peak. Below the red belt the rocks are darker and more mixed (C, D, and E). On the moraine on the east side of the Urban glacier, under Guiuku, vast masses of granite had fallen, many of the blocks recently. It is fine grained, and of grey colour (F).” (1.) Taw Tetnuld.—Specimen from the highest rocks about 100 feet below the actual summit, which was covered with snow. Mr. Donkin states that the rock traversed in the ascent: appeared to be exactly of the same character. This is a flat fragment of a brownish, rather fissile, but strong, mica schist, about + inch thick and nearly 2 inches broad and long.. The broad surfaces are spangled with small flakes of a silvery mica, and appear to be those of a “ cleavage foliation.”” Examined microscopically, the chief constitutents are — quartz and mica, besides which an iron oxide occurs, frequently in small granules and rods, and more rarely in larger grains. The quartz and mica have a general elongated ‘lenticular arrangement parallel with the broader surfaces of the fragment, and cracks traverse the slide in the same direction. The quartz on applying the polarising apparatus is broken up into a mosaic of different sized grains united by diverse tinted margins, so that we are evidently dealing in each case with one or more. grains which have been crushed up and re-cemented. Cavities are sometimes rather numerous, and * Near Zermatt in the Pennine Alps. These schists are referred to the upper- most group (Graue kalkhaltige Schiefer) in the crystalline series of the Alps. a20 ow Prof EAGe: Bonneye. “On the [May 5, occasionally tend to range themselves perpendicularly to the lines of cleavage. They are generally minute, sometimes. stained internally, both ovoid and irregular in form, usually containing fluid, and with bubbles which, as a rule, are about one fourth the volume of the cavity, but not rarely exceed this. Some of the large grains exhibit: the usual indications of being in a state of strain. The mica is brown, greenish, or colourless. The first and second are biotite, more or less altered. The colourless mica resembles muscovite, but 1 think that at any rate some of it is a magnesia- potash mica, possibly hydrous, a secondary product after biotite, the iron having separated out. This often remains between the cleavage planes in rods and plates. Possibly some of the smaller flakes of mica may be altogether of secondary origin, but I have no doubt that most of it, including all the larger flakes, is an orginal constituent. These flakes often afford marked evidence of mechanical disturbance. - They are bent, twisted, crumpled, and in some cases crushed up. Portions of them, viewed with the polarising apparatus, have a peculiar “ nowdered ” look, which I find very characteristic of a mica that has been to a certain extent crushed in situ, so that, while the general outline of a crystal is preserved, there are constant ruptures of con- tinuity and slight displacements of the constituent parts. A few small mineral granules also occur in the slide; some I am disposed to refer to epidote, others to a very impure garnet. (2.) The specimens from Guluku were collected, partly in situ ata - height roughly of 14,500 or 15,000 feet above the sea, partly from a moraine, as above-mentioned, on the Urban glacier; hence they repre- sent a considerable mass of the mountain below the level just men- tioned. The highest point of Guluku is about 16,500 feet above the sea. (A.} From the highest rocks reached. A small fragment of rock with indications of a slight cleavage, consisting of a porcelain-white mineral irregularly mottled with one of a pale pistachio-green colour. The former on microscopic examination proves to be a plagioclastic felspar, considerably decomposed, but in parts showing very clearly a lamellar twinning. The extinction angles are generally rather small, probably oligoclase predominates; microlithic flakes of a micaceous mineral, and other decomposition products, are frequent. The other mineral is an epidote, varying from a pale yellow tinge to colourless, and rather impure. lt occursin aggregated and sometimes rather fan- like groups of longish crystals. There are also a few spots of a serpentinous or chloritic mineral. The mechanical disturbance of the rock is obviously posterior to the crystallisation of the felspar, as its crystals are cracked and even sheared, but, at any rate in the main, prior to that of the epidote. Gulukw (B).—A small fragment. of a coarse gneissose rock, evi- 1887.] Structure of Locks from the Caucasus. | 321 dently containing a considerable amount of a darkish mica, on the weathered surfaces reddish-brown (the ‘“‘red band’’). Under the microscope it is seen to consist chiefly of biotite, felspar, considerably decomposed, in part at least plagioclase, and quartz. The biotite is in places altered into a greenish chloritic mineral, in others is “bleached ” by parting with its iron. A white mica, however, which occurs in good sized flakes, appears to be an occasional original constituent. The rock has evidently been much crushed. The quartz is cracked and displaced, the felspar has been broken up, and parts of the original crystals are now occupied by a sort of irregular mosaic or mixture of felspar, quartz, kaolin, and white mica. The felspar crystals are occasionally interrupted by roundish inclusions of quartz, such as one often sees in the oldest gneisses. These may be of secondary origin, but I find nothing to prove it. The original quartz grains, where adjacent to the crushed felspar, appear to have been augmented by secondary deposits of quartz in optical continuity. The mica in parts of the slide shows marked indications of mechanical disturbance, and a reddish garnet at the edge has been distinctly crushed out, as is more fully described in (C). Guluku (C).—This specimen, in shape roughly a right- rhomboidal prism about 1” x 1” x $”, has for its larger Shea parallel joint surfaces; two others are ‘ Aiea surfaces,” parallel with which the fractured faces exhibit a,foliated structure. The rock appears to be a strong rather compact mica-schist, dark in colour, with a few very thin lighter-tinted bands. The principal minerals are quartz, mica, garnet, iron oxide, and a quantity of a brownish mineral, sometimes very fibrous. The quartz occurs mostly in granules of moderate size, occasionally including a little minute rutile (?) and mica. It is on the whole fairly clear, but here and there cavities are pretty numerous. These frequently con- tain bubbles, which, though very variable in relative size, are gene- rally smaller than in the Tau Tetnuld rock, perhaps commonly about one-sixth or one-seventh of the whole volume. The mica constituent is chiefly biotite or its alteration products, often a greenish chloritic mineral, sometimes a whitish hydrous mica, both with interlamination of iron oxide. The garnet is colourless in thin slices, and occasionally exhibits, along cracks, alteration for a short distance into a chloritic mineral. Some of the larger granules of iron oxide are hematite. The pale-coloured rather filmy or fibrous mineral is certainly in some cases a secondary product after a felspar, the usual aggregate of a minute micaceous or kaolinitic mineral. Other parts, however, con-, sisting of narrow undulating bands of an aggregated fibrous mineral,. like a small lock of wavy hair, I was at first disposed to regard as fibrolite, but after repeated examination I am unable to decide. They resemble in some respects a fibrous mica, but their extinction 322 _ Prof. T.G. Bonney. On the — [May 5, does not appear to agree with this mineral (though accurate measure- ments are difficult to obtain) for it seems markedly oblique. It is evident at a glance that this rock has been subjected to a great pressure normal to the conspicuous foliation. The garnets have been cracked and crushed out, so as to have become elongated ovals in shape. A glance at the diagram will render a more minute descrip- tion needless, and will show that the garnet was more or less flattened out before it broke. The quartz grains also are cracked, being some- times only a little, sometimes much displaced. This mineral, however, does not appear to have been so completely crushed up as in the Tan Tetnuld schist. Occasionally a small grain, adjacent to the (original) felspathic constituent, has escaped altogether. The felspar has, I kelieve, often been crushed out, and then converted into the above- named microlithic mineral. The larger mica flakes are twisted about in the manner usual in a rock which has been crushed. Study of this slide seems to me. to show conclusively that this rock, anterior to the crushing, was a moderately coarse erystalline rock, consisting chiefly of quartz, felspar, biotite, and garnet, probably a rather mica- ceous gneiss. Garnet, squeezed out and cracked ; surrounded by biotite, quartz and the fibrolitic mineral. x 25 diam. Guluku (D).—A small fragment of a micaceous granitoid rock. Except for the greater abundance of biotite and the smaller amount of quartz this rock is closely allied to the next described ; the felspar is a little more decomposed, and small garnets are rather more numerous. With these modifications the description given below applies here, and this rock, too, has evidently undergone about a similar amount of mechanical disturbance. Another small fragment from about the same level contains more white mica, but as the general aspect suggests no important difference, and it is not a very promising specimen, I have not had a section made, This occurs ata slightly lower level than (B), and the two are about 100 feet below (A). 1887.] Structure of Rocks from the Caucasus. 323 Guluku (F).—Section from one of two specimens representing numerous large blocks of granite fallen from west side of Guluku. This is a fairly coarse-grained rock, chiefly consisting of a white felspar and dark mica, not rich in quartz. The mica is mainly biotite in good preservation. Thereis also a certain amount of a white mica which appears to be an original constituent and to belong to the muscovite group. The felspar is occasionally replaced by kaolinite and micaceous minerals, but much of it is in good preservation ; sometimes one part of a crystal is reduced to an ‘earthy ”’ condition, while the rest is quite fresh. Most of the crystals show the twinning of plagioclase, generally on the albite type, but occasionally on the pericline. One of the grains appears to be microcline. I have measured the extinction angles of several parallel lamelle; it is difficult to get very satisfactory results, but, as in two of the best cases, they appear distinctly too large for albite, between 30° and 40°, the felspar is probably oligoclase. There are two or three small colourless garnets, with probably a little apatite. The quartz contains cavities, in which small bubbles are usually present, about one-sixth or -one-seventh of the volume. This rock has evidently been subjected to a certain amount of mechanical disturbance since its consolidation. The quartz grains are cracked and show strain-polarisation. The felspar lamelle are occasionally bent, now and then cracked across, but the effects are _ shght compared with the other cases. Mr. Donkin also collected a specimen some miles further down the valley which resembled the rock in a neighbouring cliff. This ap- pears to be a reddish rather fine-grained felspathic granite, but as it was not obtained in situ I have not had a slice prepared. The evidence of these specimens does not appear sufficient to warrant any positive statement as to the origin of these Caucasian rocks. The structure of one (D) seems rather to favour the idea of its having been a true granite (7.e., an igneous rock); the same is true also of (F); while in another (B) there is a structure, which I have some reason to think characteristic of the Archean gneisses.* But in the present state of our knowledge it would be unsafe to rely too much upon the latter criterion, because we do not yet know what modifications may be introduced by subsequent re- arrangement of mineral constituents. It has indeed been proved in the case of hornblendic rocks, that the original structures, character- istic of crystallisation from a state of fusion, may be wholly obliterated ; * The same difficulty exists in the case of some of the more highly crystalline rocks of the Alps. Favre (‘ Recherches—Chaine du Caucase,’ p. 70) states that the central part of the Caucasus is “ granite,’ which he compares with the protogine of the Alps, with a considerable belt of crystalline schists on the north, and an inter- mittent one of the same, followed by slates, on the south. 324: Structure of ‘Rocks from the Caucasus, [May B, the same may take place also with granitic rocks. Still, even if this mode of metamorphism has occurred, there is some reason to believe that it dates usually, if not invariably, from a very remote period. We can, however, in my opinion, venture to assert that these Cau- casian rocks, after they had assumed a. crystalline condition, under- went great pressures, regional rather than local in their operation, which to some extent crushed the constituents, and gave rise to cer- tain mineral changes. It seems then a legitimate inference that in this part of the Caucasus, as in the Alps, the fundamental rocks con- sisted of crystalline rocks of more than one type, at a period long anterior to the operation of the pressures which folded this part of the earth’s. crust and upreared the mountain range. (3.) The huge mass of Elbruz appears to consist mainly of volcanic. rock, and is crowned by two crater-peaks almost equal in height. Of’ these the eastern, which is believed to be very slightly the lower of the two, was ascended for the first time on July 31st, 1868, by Messrs. ’ Freshfield and Moore. On this occasion the western summit was so entirely concealed by clouds that its existence was not even suspected. The western summit was first ascended on July 29th, 1874, by Messrs. Grove and Walker. Its “crater considerably exceeds in size that on the twin summit, and is probably about ? of a mile in diameter. ‘The wall is perfect for some two-thirds of its former circuit, but on the south-west side a vast piece has fallen away, and a great glacier now flows down from the gap.” The little peak forming its highest point, juts up on the north-eastern segment of the limb. Its height above the sea, according to the Russian survey, is 18,526 feet, the eastern summit being 95 feet lower. The col between the two summits, according to Mr. Grove, is about 17,350 feet. The specimen collected by Mr. Walker was from the highest rocks traversed on the western peak, perhaps about half-way between the col and the summit. It is a rough slab of a grey lava, with occasional small irregularly-shaped vesicles, and scattered crystals of- a whitish felspar up to about + inch in length. The weathered parts. are of a lightish-brown colour. Microscopic examination shows that the rock has a clear glassy base crowded with minute lath-like felspar microliths, apparently oligoclase, and occasional specks of opacite and aggregates of ferrite : possibly some minute granules of a pyroxenic mineral are present. To the same epoch of consolidation may belong some occasional elongated crystals of a light-coloured hornblende, but this 1s uncertain —there are a few grains of iron oxide, probably hematite. The larger crystals in the slide certainly belong to an anterior consolidation—these are (1) a dark brown hornblende, often with rounded outline, and sometimes blackened with included opacite; (2) a felspar, which generally resembles labradorite or andesine, but in one or two cases. 1887.] Distribution of Strain in the Earth's Crust. - 325 may possibly be sanidine. It is often rounded or broken in outline, is always greatly cracked, and contains many inclusions of a pale brown glass. One grain, indeed, consists very largely of glass, in which the crystalline parts are, so to say, embedded. This suggests that the mineral has been melted down in sitw along the lines of natural fracture, rather than that it has incorporated the glass in erystallising. There are occasional cavities in the felspar, with bubbles varying in their relative size, which do not move. Grains of quartz, as observed by Tschermak (‘ Mineral. Mittheil.,’ 1872, p- 108) in specimens brought by Favre from the lava streams lower down the mountain, do not occur in this specimen. A fluidal structure is barely indicated. The rock may be named a hornblende-andesite. 1 have compared the slide with one from the upper part of Ararat (lent me by Professor Judd), and with my own collection of andesites and allied rocks from Auvergne, Germany, Hungary, Italy, Old Providence Island, and the Andes, but it differs varietally from all. III. * On the Distribution of Strain in the Earth’s Crust resulting from Secular Cooling, with special Reference to the Growth of Continents and the Formation of Mountain-chains.” By CHARLES Davison, M.A., Mathematical Master at King Edward’s High School, Bamingham. Communicated by Prof. T. G. Bonney, D.Sc., F.R.S. Beceived April 7, 1887. (Abstract.) - The paper is founded on— 1. Sir W. Thomson’s and Professor G. H. Darwin’s researches on the rigidity of the earth. 2. Sir W. Thomson’s investigation on the secular cooling of the earth. 3. The contraction theory of mountain formation. I. The Distribution of Strain in the Earth's Crust resulting from Secular Cooling. ~The following problem is solved :—A globe, of radius r, is sur- rounded by a number of concentric anitorieal shells, called Ane AGS A; .... of thickness a), dy, dg... respectively. The globe remain- ing at its initial temperature, the shell A, is cooled by #,°, the shell A, by t,°, in the same time, and so on. The linear coefficient of expan- sion being e, and the same for all the shells, it is required to find the distribution of strain resulting from this method of cooling. An expression is found giving the change of radius of the inner surface of any shell. Supposing all the shells to be of equal thick- 326 Mr. C. Davison. On Secu’ar Cooling and the [May 5, ness a, the change of radius of the inner surface of the shell A,,,; is proportional to —.[(r+na)3(tayi—tr) +(r+n—1. a)?(tr—tni)+ - +(rta)(k—-h)+rh]. . . (1) er i.e., if the shells be infinitely thin, to e ages dt | oa ? (r+na) t being proportional to the rate of cooling of any shell. If this expression be positive for any shell, the shell is stretched ; if neyative, it 1s crushed or folded. To apply this problem to the case of the earth, the law of cooling taken is that which follows from Sir W. Thomson’s solution, in his memoir on the secular cooling of the earth. The expression in the form (2) proves unserviceable, and therefore the expression (1) is made use of as follows :— Taking the time since solidification provisionally at 174,240,000 years, 1t is shown that the rate of cooling (dv/dt) is practically insen- sible at a depth of 400 miles. The radius of a sphere equal to the earth in volume being about 3959 miles, the earth is supposed to be constituted as follows :—A central globe, 3559 miles in radius, at the initial temperature of the earth, which as yet has not sensibly cooled, surrounded by 400 concentric spherical shells, each one mile in thickness, the rate of cooling in each shell being uniform through- out, and equal to its value at the outer surface at that shell. The results of the calculation are shown by the curve in the figure accompanying the paper, and the following conclusions are deduced, taking the time since consolidation provisionally at 174,249,000 years :— 1. Folding by lateral pressure takes place only to a certain depth (about five, miles) below the earth’s surface, and below this depth changes to stretching by lateral tension. 2. Stretching by lateral tension, inappreciable below a depth of 490 miles, increases from that depth towards the surface; it is greatest at a depth of 72 miles (7.e., just below the depth at which the rate of cooling is greatest) ; after this it decreases, and vanishes at a depth of about five miles. 3. Folding by lateral pressure commences at a depth of about five miles, and gradually increases, being greatest near the surface of the earth. No great importance is attributed to the numerical results. The 1887.] Distribution of Strain in the Earth’s Crust. 327 conclusions are given for their qualitative rather than their quantita- tive value. They depend also on the assumption that the earth’s surface is smooth and spherical. The following laws are also shown to be approximately true :— 1. The depth of the surface at which folding by lateral pressure vanishes, and the depth of the surface at which stretching by lateral tension is greatest, both increase as the square root of the time that has elapsed since the consolidation of the globe. 2. Folding by lateral pressure was effected most rapidly in the early epochs of the world’s history as a solid globe, and, since then, the total amount of rock folded in any given time decreases nearly in proportion as the square root of the time increases. 3. A law, similar to No. 2, for stretching by lateral tension. II. The Rev. O. Fisher’s Argument on the Insufficiency of the Contraction Theory. The argument is described (see ‘ Phil. Mag.’ for Feb., 1887). It is shown to be inconclusive on the following grounds :— 1. It assumes that the cooling of the earth to its present condition was instantaneous. 2. If instantaneous cooling were possible, there would, it is shown, be no folding at all, but only stretching by lateral tension. ». It assumes that the earth’s surface was initially smooth and spherical, whereas Professor B. Peirce and Professor G. H. Darwin have both shown that vast continental wrinkles would be formed on the surface of a once viscous earth by the diminishing velocity of rotation resulting from tidal friction. Ill. The Effects of Crust-stretching and Folding on the Evolution of the Earth's Surface-features. 1. Owing to the pressure of the continental masses, crust-stretching by lateral tension takes place principally beneath the ocean-basins, therefore deepening them and contributing totheir permanence. This effect must have been greatest in early geological periods, when the surface of greatest stretching was close to the surface of the earth. 2. In another part of the paper it is shown that the amount of crust-stretching is considerably greater than the amount of crust- folding, due directly to secular cooling. Folding beneath the ocean- bed will therefore do little but diminish its rate of subsidence. The effects of folding in changing the forms of the earth’s surface features must be most apparent in continental areas, especially along those coasts where the slope towards the ocean-depths is most rapid (.e., in the districts where earthquake and volcanic action are known to be most prevalent). In the coast regions, also, the products of conti- “328 The Geological Bearing of Mr. Davison's Paper. [May 5, nental denudation are chiefly deposited. Hence, the continents grow by the formation of mountain-chains along their borders. 3. The rate of mountain-making, and therefore also that of conti- nental evolution, diminishes with the increase of the time. IV. “ Note on the Geological Bearing of Mr. Davison’s Paper.” By T. G. Bonney, D.Sc., LL.D., F.R.S., Professor of Geology in University College, London. Received April 7, 1887. | The results obtained by Mr. Davison throw light upon one or two matters in regard to the petrology of the older rocks, which have always appeared to me difficult of explanation. I venture therefore to add a brief note to his paper, written from the point of view of a geologist. He throws light especially on the following matters :— (1.) Among the older rocks the great foldings and their results, such as cleavage, appear to have occurred when the beds formed the ‘upper layers of the earth’s crust. Thus the Ordovician rocks of North Wales were cleaved anterior to the deposit of the Silurian ; ‘the Carboniferous, and other Paleozoic rocks of South-west Britain and Britanny were plicated and cleaved, geologically speaking, shortly after their deposition. The great foldings in the Scotch Highlands occurred, in great part at least, in Silurian time. The disturbance of the Lake District rocks, resulting in ‘cleavage, must be placed between the end of the Silurian and the very beginning of the Carboniferous; that of Southern Scotland, between perhaps yet narrower limits. The first epoch of mountain making in the Central Alps, with its plication and cleavage, imme- diately followed the deposition of the Eocene rocks. The list might easily be extended. (2.) The crystalline substratum often appears to be less modified than -the overlying softer and more recent beds. This I had attributed to the greater resistency of the former, but then could not see how to explain the foldings of the latter, if the others were comparatively uncompressed. This, however, accords with Mr. Davison’s results of the diminishing effects of compression, while the fact that in early geological times the “ neutral: zone” between compression and tension was comparatively near the surface of the earth, may explain the ‘frequent parallel arrangement of the minerals in the older Archean «eneisses. I do not now refer to the more marked changes, such as .the intercalation of calcareous or micaceous rocks, of -more felspathie “or quartzose layers, whereby a stratification is simulated, if it be not recorded, but.to the fact that very often a general: parallelism may be 1887.] Dr. J. F. Main. On the Viscosity of Ice. 329 noted in the fiakes of. mica or any other mineral of somewhat like form scattered through the mass of the rock, sometimes approximating to a banding of the constituents, without any indication of this being the result of crushing. In regard to this particular structure, it is worth notice that it often lies in planes making a low angle with the horizon. (3.) The same result may help to explain the assertion so frequently made, that among the older rocks the foliation (or minor mineral banding) is commonly parallel to the (apparent) stratification (or major mineral banding). This also I have noticed in cases where either there was no indication of subsequent crushing, or the latter had not effaced, and its effects could be distinguished from, the earlier structure of the rock. I once supposed this parallelism and te dency to horizontality to be due to the weight of superimposed beds, but for some time have been dissatisfied with this explanation, because I could find no evidence that any heavy burden had been laid upon the older rocks till lony after they had assumed a foliated structure. Tension, however, would probably produce the structure at least as readily as pressure, and the former of course would, as a rule, act parallel with the surface of the earth’s crust, while compression should be exhibited commonly in planes making a high angle with it. _V. “ Note on some Experiments on the Viscosity of Ice.” By J. F. Maryn, M.A., D.Sc. Communicated by Prof. W. “ Unwin, F.R.S. Bee ined April 13, 1887. (Abstract. ) The paper contains an account of some experiments on the con- tinuons extension of bars of ice subjected to tension, made during the last wimter in the Engadine. To eliminate the influence of rege- lation, the experiments have been carried on at such low temperatures as preclude the possibility of any effect being produced by this cause. The highest temperatures during the experiments were —2°:6° CG. in Experiment I; —1:0°C. in Experiment II; and —0°5°C. in Expe- riment III. These maximum bemparalares only obtained for a very short time on one or two days. The bars were tested in a compound lever testing machine with accurate knife edges, the load being a known ae of shot. The whole apparatus was enclosed in a double wood box. . If, however, the oxygen of a hydroxyl group is held in loose com- bination, the formation of phosphorus oxychloride and. the substitu- tion of chlorine take place simultaneously. What, however, will happen when the substitution of oxygen is difficult, as in phenol or the aromatic oxyacids? Attempts to answer this question are now Be 1887. ] On the Electrodeposition of Alloys, Sc. 387 in progress in the laboratory of the Chemical Institute of the University of Bonn, and we anticipate that the result will be the preparation of bodies having the general formula R’OPCl,. XII. “ Note on the Electrodeposition of Alloys and on the Electromotive Forces of Metals in Cyanide Solutions.” By SILVANUS P. THompson, D.Sc., B.A. Communicated by Professor G. Carrey Fostrr, F.R.S. Received May 12, 1887. It is known that the electrodeposition of such alloys as brass, bronze, and German silver is not practicable from mixed solutions of the sulphates or chlorides of the constituent metals, but can be accomplished by using cyanide solutions or neutral solutions con- taining cyanide of potassium in excess, thereby apparently departing from the law of Berzelius that out of a solution of mixed metals the least electropositive metal is deposited first. To ascertain the cause of these facts the author has investigated— (a.) The electromotive forces of a number of metals in aqueous ‘solutions of cyanide of potassium. (b.) The dependence of these electromotive forces, in particular those of copper and zinc, upon the degree of concentration of the solution. (c.) The variation of the electromotive forces of copper and zinc in a standard solution of cyanide of potassium at varying temperatures. (d.) The electromotive forces of zinc and copper in a “ brassing ” solution consisting of the mixed cyanides of zinc and copper, having excess of cyanide of potassium present, and their variation at different temperatures. It is found that the effect of higher concentration of the cyanide ‘Solutions is invariably to increase the electromotive force of copper more than it increases that of zinc. In a cold dilute solution of cyanide of potassium the electromotive force of zinc against carbon is 1°158 volt, while that of copper against carbon is 0°948 volt, or zinc is 0°210 volt higher than copper. In a boiling saturated solution of cyanide of potassium, the electromotive force of zinc against carbon is 0°768 volt, and that of copper against carbon is 1°300 volt; or copper is 0°532 volt higher than -zine. Ii is therefore possible to construct a voltaic battery containing one metal only, namely copper, and one electrolyte only, namely an aqueous Solution of cyanide of potassium, kept hot at the anode and cold at the cathode of the cell. In cyanide solutions containing about the following number of 388 On the Electrodeposition of Alloys, bc. [June 16,. grams of cyanide to the litre, the following were the electromotive: forces observed with a carbon cathode :— Solution containing per litre —eEeE—e—eE—————e—e—e—Eee (CRE OUP a mate cay 99 °4: grams. 191 °4 grams. 1°18 grams. : Metals at 18° C. Zine \y...6.-2+« 17520 | Copper .r........ 1°434 | Zime seen eee Copper i. :-<> c 1°425 | Zinc..... eesve. 1°401 | Brags, toy ee ee osrr Brass.......-.. 1°400 | Brass.......... 1°315 | German silver ~,.20°50 |: German silver 1°05 German silver 0°986 | Dead 2 t.s2a sen acae Gold: janice ors oie 0°885 | Gold ........... 0°834 |. Copper, ..0s. see WOO Silvie ae aeanioe 0°845 | Silver ..... «ee. O°810 |, Silver eee Lead .. 0:64 | Lead ssecees 07609 Goldens. cote Tron . One coimomese S58... 0°181:| Steel ..c. se saan Steel .. saad Steel .. eoeee O'161 | Tron, 226 ee eer Platinom ...... 0°27 | Platmum ...... 0°O17 |" Platmum.>) >.) eee Carbon tielie cee (0 Carbon’2. s+... 0 Carbon. 23s: eu. ao Several of the metals exhibit maximum electromotive force at an intermediate concentration. The following figures were obtained for zinc and copper in solutions. of cyanide of varying strengths at 17° C. :— Grams per litre. E.M.F. zine. E.M.F. copper. | Difference Z—C. | 2) Sa Ag ae Reierailets 1°158 0-948 +0°210 SO AGO OO DAR GOO NO oe 1°167 0°967 +0200 ULSAN S aaige ontdo oats. 1°184 1-018 +0°166 APD RIS WieNeelieve) a! ave/atia elinyote) 1°221 1-058 +0°163 ND seed esol Sina ice sega yalinla 1°269 1°130 +0°1389 OD has eg ance snes aa 1°303 1 +220 +0080 WUT eisai so wipes eerie! ee 1°355 1-360 —0°005 In a mixed solution of cyanides of zinc and copper there is a. neutral condition where the electromotive forces of zinc and copper are equal, and this neutral condition varies with the relative amounts. of metal present, with the concentration of the solution, and with the temperature. The neutral temperature for a solution of given con- centration is lowered by adding cyanide of potassium, and is raised by adding ammonia. The neutral point, however, is not well defined, the behaviour of copper being very uncertain; in general the electromotive force of clean copper in a cyanide solution rises, in‘ some cases as much as 0°06 volt, in a few seconds after immersion, but is rapidly though temporarily lowered on agitation. 1887.] The Fructification of the Carboniferous Calamites. 389 Since the degree of concentration of the solution greatly affects the electromotive force of the metal, and since in the act of deposition of a metal from its solution the concentration of the liquid around the cathode is reduced, owing to slowness of diffusion, it follows that in electrodeposition the counter electromotive force at the cathode will vary with the rate at which metal is being deposited, and will, therefore, vary with the current-density employed. And since, more- over, the variations in electromotive force due to differences of con- centration are greater for copper than for zinc, it follows that in the deposition of brass from a mixed solution of cyanides of a medium concentration in which zinc is slightly more electropositive than © copper, there will be a certain density of current with which the metals will be deposited in nearly equal quantities, whilst for weaker current-densities the less electropositive metal will be deposited in excess, and for stronger current-densities the more electropositive metal will be deposited in excess. Hence to variations in the concentration of the electrolyte near the cathode are due the departures, observed with all currents except weak ones, from the law that out of a solution of mixed metals the least electropositive is deposited first. XIII. “On the true Fructification of the Carboniferous Cala- mites.” By WILLIAM CRAWFORD WILLIAMSON, LL.D., F.R.S., Professor of Botany in the Owens College and the Victoria University. Received May 17, 1887. (Abstract. ) The true systematic position of the Carboniferous Calamites has long been a debateable subject, owing to the lack of satisfactory evidence respecting the character of their fructification. Some years ago, Mr. Carruthers and the late Mr. Binney expressed their con- viction that Calamostachys Binneyana stood in that relationship to Calamites, a conclusion which the author was unable to accept; but in 1869 he obtained a fragment of a new Cryptogamic fruit, of which he published an account in the ‘ Memoirs of the Literary and Philo- sophical Society of Manchester.’ The central axis of this Strobilus presented so many details of structure hitherto seen only in Calamites as convinced the author that it was the true fructification of these plants. Many years elapsed before a second example of this interesting - fruit was discovered, but seven or eight specimens of it recently - found ina nodule from near Oldham, have come into the author’s possession; these examples are in a sufficiently excellent state of 390 Sir Richard Owen. On Echidna Ramsayi (Ow.). [June 16, preservation to enable him to illustrate almost every detail of their structure. They not only support his previous conclusions, but they supply irresistible evidence that those conclusions are correct ones. Fortunately, at least three of the Strobili have attached to them the ends of the twigs which supported them; these peduncles are indisputably Calamites of the type to which Géppert assigned the generic name of Arthropitus, which genus several of the French Paleontologists have long insisted upon classing with the Gymno- spermous plants. ; The fruit is beyond question that of a true spore-bearing Crypto- gam; a fact which determines the Hquisetiform affinities of the entire Calamitean group; since if any members of that group might possibly have been regarded as Gymnosperms, it certainly was those of the Arthropitean type. But of all such possibilities there is now an end. XIV. “On Fossil Remains of Echidna Ramsayi (Ow.). Part IL.” By Sir RicHarp Owen, K.C.B., F.R.S., &. Received May 20, 1887. (Abstract. ) Since the transmission of the evidence of the large extinct species of Hchidna, the subject of the paper (‘ Phil. Trans.,’ 1884, p. 273, Plate 14), the discoverer of the specimen, Hd. P. Ramsay, Hsq., F.L.S., has prosecuted his researches in the ‘‘ Wellington bone and breccia caves, New South Wales,” and has added to the mutilated subject of that paper an entire humerus, a large portion of the skull, the atlas vertebra, a tibia, and fragmentary evidences of other parts of the same skeleton—adding to the knowledge of a former existence in Australia of Hchidna Ramsay. The edentulous condition, proportions, and conformation of the jaws, together with other characteristic modifications of this mono- trematous genus, are repeated on the same magnified scale as in the mutilated arm-bone previously described and figured. The predatory subject of the paper on Thylacoleo carmifew (‘ Phil. Trans.,’ 1887) was discovered in the same cave, and exemplifies the leonine marsupial which contributed to the extinction of the larger phytophagous and monotrematous Mammals of the Australian Con- tinent. 1887.] On the Young of the Ornithorhynchus paradoxus. 391 XY. “ Description of a Newly-excluded Young of the Ornitho- rhynchus paradoxus.” By Sir RICHARD OwEn, K.C.B., F.R.S., &c. Received May 20, 1887. (Abstract.) Of this interesting and long-hoped-for discovery the author was informed by his friend and correspondent, the Baron von Mueller, F.R.S., of the Botanical Gardens, Melbourne, and shortly received the specimen from the Baron: also, further details from Mr. Le Souef, of the Zoological and Acclimatisation Society’s Office, Melbourne ; and from the Rev. Pastor Hagenauer, Superintendent of the Mis- sionary Station in Gipps-Land, S.E. Victoria, to whose influence with the natives science is indebted for the acquisition, as I am to Baron von Mueller for the reception, of the embryo well preserved in alcohol. The specimen is nude, an inch in length, the nostrils well opened, and between them the fleshy conical support of the horny sheath, which has been shed and by which the chorion had been torn open at birth. The mouth is a transverse slit, not produced as a_ beak, bounded by flexible lips, and sufficiently open to receive nutri- ment afforded ky the group of pores excluding the secretion of the mammary gland of the pouch. The fore limbs, chiefly represented by the paws and pentadactyle, with claws sufficiently developed for adhering to the part of the pouch on which the excretory pores open. The hind limbs are less developed, have the five digits feebly indicated and clawless. A short conical-pointed tail projects between them. The elongate, flattened, natatory tail of the adult is a later develop- ment. There is no trace of navel. The skin of the trunk is uniformly smooth and nude. If this embryo should be a male, the spur of the femoral gland is a defensive organ of later growth. The author refrains from dissection in hopes of receiving another specimen; and, after a detailed description of the external characters of the unique specimen, refers to his paper ‘‘On the Uterine Ovum of the Ornithorhynchus”’ in the volume of the ‘ Philosophical Trans- actions’ for 1834, and on the “Mammary Glands” in the volume for 1832. : «* 392 Dr. A. B. Griffiths. On the [June 16, XVI. “On the Nephridia and ‘Liver’ of Patella vulgata.” By A. B. GRiFFITHs, Ph.D., F.R.S. (Edin.), F.C.S. (Lond. and Paris), Principal and Lecturer on Chemistry and Biology, School of Science, Lincoln. Communicated by Sir RICHARD OWEN, K.C.B., F.R.S. Received May 20, 1887. Patella vulgata (Limpet), with its conical shell adhering to the rocks of our coasts, is well known to every sea-side wanderer. This member of the Gasteropoda has been the subject of many scientific memoirs in ancient and modern times. Amongst naturalists, Aristotle was the earliest who gave an account of some of the limpet’s habits, and Cuvier was the first to describe its anatomy. In this paper the author intends to describe the chemical properties of the secretions of two problematical organs of this interesting little Gasteropod. The author has already proved the renal function of the green glands of Astacus fluviatilis (‘ Roy. Soc. Proce.’, vol. 88, p. 187) ; also, In conjunction with Mr. Harold Follows, F.C.S., the renal function of the organs of Bojanus in Anodon (‘ Chemical News,’ vol. 51, 1885, p. 241; ‘Chem. Soc. Journ.,’ vol. 48, 1885 [Abstr.], p. 921). Since the publication of those papers, Dr. C. A. MacMunn (‘ Journ. of Physiol.,’ vol. 7 [No. 2], p. 128) has extracted uric acid from the Malpighian tubules of insects and from the nephridia of the Pulmo- nate Mollusca. I. Nephridia of Patella vulgata. The nephridia of Patella vulgata consist of two parts, left and right lobes. The left nephridium is very small in comparison to the right nephridium. The anatomy and histology of these organs have been fully described by Prof. Lankester, F.R.S. (‘ Ann. Mag. Nat. Hist.,’ vols. 20, 1867, and 7, 1881), J.T. Cunningham (‘ Quart. Journ. Microsc. Sci.,’ vol. 22, p. 369), and Harvey Gibson (‘ Edinb., Roy. Soc. Trans.,’ vol. 32, pp. 617—620). After dissecting the nephridia from the bodies of a large number of fresh limpets, the secretions of the left nephridia were examined separately from those of the right nephridia. Both secretions were examined chemically by two separate methods as follows :— (a.) The clear liquid from the nephridia was treated with a hot dilute solution of sodium hydrate. On the addition of hydrochloric acid a slight flaky precipitate is obtained after standing for some time. These flakes when examined microscopically are seen to consist of small rhombic plates and other forms. On treating the secretion alone with alcohol, rhombic crystals are deposited which are soluble in water. 1887. | Nephridia and “Liver” of Patella vulgata. 393 When these crystals are treated with nitric acid and then gently heated with ammonia, reddish-purple murexide [C,H,(NH,)N;O,]| is obtained which crystallises in prisms. (b.) Another method was used for testing the secretion of the nephridia of Patella. The secretion was boiled in distilled water, and evaporated care- fully to dryness. The residue so obtained was treated with absolute alcohol and filtered. Boiling water was poured upon the residue, and to the aqueous filtrate an excess of pure acetic acid added. After standing about seven hours, crystals of uric acid (C,H,N,O,) were deposited, and easily recognised by the chemico-microscopical tests mentioned above. The secretions both of the left and right nephridia yield uric acid. It has been suggested by Mr. R. J. Harvey Gibson, M.A., F.R.S.H. (in his masterly memoir on the “ Anatomy and Physiology of Patella vulgata;” * Kdinb., Roy. Soc. Trans.,’ vol. 32, pp. 601—638), that the secretions of the two nephridia may be chemically distinct. The author could not extract or detect (after a most searching investiga- tion) the presence of any other ingredient besides uric acid in either secretion. From this investigation, the isolation of uric acid proves the renal function of the nephridia of Patella vulgata. Il. The “ Liver” of Patella vulgata. In a paper on the Cephalopod “liver” (‘ Hdinb., Roy. Soc. Proc.,” vol. 13, pp. 120—122), the author proved from a chemical and micro- scopical study of its secretion that it possesses the function of a true pancreas or digestive organ. Since the publication of the above paper, the author has investi- gated the nature of the secretions of various doubtful organs of the Invertebrata.* The “ liver” of Patellais a yellowish saccular gland, and the greater bulk of this organ is encircled by the superficial coil of the intestine. (a.) The secretion of the gland acts upon starch-paste, converting the starch into glucose-sugar, as proved by the use of Fehling’s: solution. (b.) The secretion produces an emulsion with oils and fats, yielding subsequently fatty acids and glycerol. (c.) When a few drops of the secretion of the gland are examined * See Dr. Griffiths’ paper, ‘“ Researches on the Problematical Organs of the Invertebrata, especially those of the Cephalopoda, Gasteropoda, Lamellibranchiata, Crustacea, Insecta, aud Oligocheta.’””—Read before the Royal Society of Hdin- burgh, May 16, 1887. 394 Prof, Carnelley and Mr. J. 8, Haldane. [June 16, with chemical reagents under the microscope, the following reactions were observed :—On running in between the slide and cover-slip a solution cf iodine in potassium iodide, a brown deposit was obtained. On running in concentrated nitric acid on another slide containing a drop or two of the secretion, a yellow coloration was formed, due to the formation of xantho- proteic acid. These two reactions show the presence of albu- min in the secretion of the organ in question. (d.) The soluble ferment secreted by the columnar cells of the epithelium of the gland was extracted according to the Wittich- Kistiakowsky method (‘ Pfliiger, Archiv Physiol.,’ vol. 9, pp. 438—459). The isolated ferment converts fibrin into leucin and tyrosin. (e.) No glycocholic and taurocholic acids could be detected by the Pettenkofer and other tests. No glycogen was found in the organ or its secretion. 3 (f.) The secretion contains leucin and tyrosin. From these investigations the conclusion to be drawn is that the so-called “liver” of Patella vulgata is similar in function to the pancreas of the vertebrate division of animal life. XVII. “ The Air of Sewers.” By Professor CARNELLEY, D.Sc., and J.S. HALDANE, M.A., M.B., University College, Dundee. Communicated by Sir H. Roscox, F’.R.S. Received May 21, 1887. (Abstract). Owing to the complaints which had been made of bad smells in the House of Commons a Select Committee was appointed in the spring of 1886 to inquire into the ventilation of the House. By that Committee the authors were instructed to make a series of analyses of the air in the sewers under the Houses of Parliament, and to report thereon. Since then they have examined a considerable number of sewers in Dundee, and have also made a number of laboratory experiments. The object of the research was to obtain a general idea of the amount of some of the more important im- purities in sewer air, and to throw some light on their sources, and the conditions affecting their dissemination. After giving a brief réswmé of the results of the analyses which had been previously made of sewer air, the authors describe the methods they have employed, and the nature and condition of the sewers they have themselves examined. As a result of their investigation they found—(1.) That the air of 1887. | The Air of Sewers. 395 the sewers examined was in a much better condition than might have been expected. (2.) That the carbonic acid was about twice, and the organic matter rather over three times as great as in outside air at the same time, whereas the number of micro-organisms was less. (3.) That in reference to the quantity of the three constituents named the air of the sewers was in a very much better condition than that of naturally ventilated schools, and that with the notable exception of organic matter it had likewise the advantage of mechani- cally ventilated schools (cf. paper by the authors and Dr. Anderson in ‘Phil. Trans,’ 1887). (4.) That the sewer air contained a much smaller number of micro-organisms than the air of any class of house, and that the carbonic acid was rather greater than in the air of houses of four rooms and upwards, but less than in two- and one- roomed houses. As regards organic matter, however, the sewer air was only slightly better than the air of one-roomed houses, and much worse than that of other classes of houses. (The data for all the classes of houses refer to sleeping rooms when occupied during the night.) The amount of carbonic acid found by the authors was much less than that noted by earlier observers, showing that the sewers they examined were much better ventilated than those previously investi- gated. On taking the average of a comparatively large number of analyses it was found that the quantity of organic matter in sewer air increased with the carbonic acid, whereas the micro-organisms on the whole decreased with increase of the other constituents. With regard to the sources of the several impurities in sewer air the following conclusions are drawn :—(1.) The carbonic acid in excess of outside air may be partly due to diffusion from the neighbouring soil, but its chief source is probably the oxidation of the organic matter in the sewage and in the air of the sewer. (2.) The organic matter in excess of outside air is most probably wholly or for the most part gaseous, and is of course derived from the sewage itself. (3.) The micro-organisms in sewer air come entirely, or nearly so, from the outside, and are not derived, or only in relatively small numbers, from the sewer itself. This is proved by the following facts :—First, the average number of micro-organisms in sewer air was less than in out- side air at the same time-—viz., about 9 in the former to 16 in the latter. Second, the number increased with the efficiency of the ventilation. Third, the average proportion of moulds to bacteria in sewer air was almost exactly the same as in outside air at the same time, whereas one would expect the proportion to be very different were the outside air not the source from which they were derived, seeing that such a difference has been proved to exist in the air of houses, schools, &ec. Fourth, the naked eye appearance of the colonies from sewer air is 396 Dr. A. Scott. [June 16, similar to that of those from ordinary air. ifth, the state of filthi- ness of a sewer seems to have no perceptible effect on the number of micro-organisms. Siath, the view that the micro-organisms in sewer air chiefly come from outside, is in perfect agreement with what is known as to the distribution of bacteria in air. Seventh, results obtained in the laboratory with an experimental sewer prove that the micro-organisms present in air are diminished to nearly one-half in passing along a moist tube 5 feet long and 12 inch in diameter at a rate of nearly 1 foot per second. Although most of the micro-organisms in sewer air come from outside, yet there was distinct evidence of their occasional dissemination from the sewage itself. This is the case when splashing occurs, owing to drains entering the sewer at points high up in the roof. It is, therefore, of great importance that drains should be so arranged as to avoid splashing as much as possible. In view of the fact that ordinary sewer air is to all appearance comparatively innocent as regards its micro-organisms, experiments were also made to see whether it contained any poisonous volatile base of the nature of a ptomaine. These experiments so far as they went had negative results. Experiments as to the efficacy of ordinary water traps in preventing the escape of sewer gas into houses confirmed and extended the results previously obtained by Fergus. Though the authors do not discuss the effect of the inhalation of sewer air on health, yet the results of tho above investigation are clearly such as to make one much more suspicious as to supposed evidence of the bad effects of ordinary sewer air (at least when not vitiated by splashing), such as that examined by them. f XVIII. “On the Composition of Water by Volume.” By ALEXANDER ScoTT, M.A., D.Sc. Communicated by Lord RAYLEIGH, D.C.L., Sec. R.S. Recetved May 23, 1887. In 1805 Gay-Lussac and Humboldt published their classical re- searches on the composition of the atmosphere, and to them we are indebted for our knowledge of the proportion by volume in which hydrogen and oxygen combine to form water. Without this know- ledge the determination of the relative densities of the two gases would be of no use in fixing or checking their atomic weights. This is often overlooked, and Avogadro’s law taken as absolutely true for these gases at ordinary temperatures and pressures. That this cannot safely be assumed is conclusively proved by the researches of Regnault, Amagat, and others on the effects of change of temperature and pres- sure upon them. Not only do they not follow Boyle’s law as usually 1887.] On the Composition of Water by Volume. 397 understood, but their deviations from it are in opposite directions; hence it can only be by the merest chance that at our ordinary temperatures and pressures the combining volumes should be exactly two of hydrogen to one of oxygen. Moreover, when we consider that it is more than eighty years since these researches were carried out, that the instrument used in all the measurements was Volta’s eudiometer, and that the gases were collected and measured over water and so contained impurities to the extent of 0-4 per cent. in the oxygen and 0°6 to 0°8 per cent. in the hydrogen used, a redetermi- nation of this ratio with the greatly improved means for attaining accuracy now at our command seemed to be of extreme importance. The exact ratio as given in the memoir referred to is 199°89 volumes of hydrogen to 100 volumes of oxygen, and this the authors say is almost exactly as 2: l. To arrive at greater accuracy the autnor of this note has given especial attention to the following points :— (1.) The preparation of purer gases. (2.) The use of larger volumes. (3.) The measurement of both gases in the same vessel. (4.) The analysis of the residue after explosion and determination of the impurity in each experiment. SSq°$ew G y Y Y G G Y G G J Y Y Y Y Y Y Y G - Y J g Y Y Y Y Z Y Y G Z Z % Y Ny N NS 398 Dr. A. Scott. [June 16, These ends were more or less satisfactorily attained by the use of the apparatus employed, which was entirely of glass with the excep- tion of the junctions at H and O. The gas generators contained only small volumes of gas, and could easily be exhausted by means of the apparatus itself. It is evident that by filling A and B with mercury, completely closing all the stopcocks, and then lowering M and open- ing e, the air in the oxygen generator would be in great part drawn into A; on now closing e and raising M this air could be expelled by opening f. By repeating this several times an almost perfect vacuum could be produced. Before collecting the gas for the experiments, after exhausting the air gas was evolved and exhausted, and this again repeated. The gases were measured saturated with moisture, and after measurement were expelled into G; from this they were drawn into E and exploded, and the residue measured in a small tube and analysed by explosion with either hydrogen or oxygen as re- quired. The results of every experiment made are given in the following table, from which it will be seen that in no case, even when the maximum value is given to it, does the ratio exceed 2 vols. of hydrogen to 1 vol. of oxygen, although in four cases it is exactly Oe a. The mean of the twenty-one experiments gives the ratio— 1:9857 : 1 from Column E. 1:9941 : 1 os R, Excluding experiments IV and VI, in which the gases contained much impurity, we get the ratio— 1:9897 : 1 from Column E. 1:9959 : 1 & F, Taking experiments I, III, XV, and XVIII, in which the purest gases were used, we get— 1:9938 : 1 from Column E. 1:9964 : 1 i i or taking experiments I, IIT, XIV, XV, XVIII, and XX we get— 19938. 1 from Column’ E. 19967 1 F. Taking as the most probable ratio 1:994:1, and the density of oxygen referred to hydrogen as 15-9627, we get the atomic weight of oxygen as 16°01. 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TSE 6-6 == G. 56 P-POL | 2.820% | T- 8P8e TL 3S co a 7866-1 | 9866-1 | 0.0881 | T-4948 | 8-188T | @-se4e | 4.2 on 8-98 | ¢-68 | S.616T | T-4c28 i Pe ‘uosorpcy | ‘uoSoaphy “109 ‘uag | 2 ; ‘mag es : ; . be : ug OO+N| ‘wos |, : . ee = je ig pe sjoa | ‘uodSxCQ -oxphy wodhXQ | _ oaphyy | Lqtandurg | -omp.qy uodk&xQ] ‘Tejoy, | ‘uestxo -ompAqq S IMOT[OF | SUTMOT[OF "(72909) | ong yyrM | 049 gt posn SOUTGULOD | SaUIqULOD ‘ : al sed ut | uodixo zo | uodxo jo uoshxo uorzodoid ours = Aqrandury omnyoOA I oun [OA I ott ur 9q 04 posod Ur Y4oq Url suroq 8B jo SOUINTOA ites bd ae ‘q uumnqoo | ‘9 uumyoo -dus suroq Aq1and | poyemnozeo Suteq ‘MOIso[dxo 10478 onprsoy pornsvoyy -1u0d xq . i MOAT Lionas “ULI [[@ ‘sournjoa | Ay1anduat ‘sournjoa S ned poyenoyey | pozetnoyeg SUIUIGUIOD Sarurq w0p oa = oS 400 Dr. W. D. Halliburton. On Muscle Plasma. [June 16, prepared from the nitrate. The hydrogen was in each case prepared by electrolysis. The water produced was free from any acid reaction, and. no trace of the oxides of nitrogen could be detected. XIX. “On Muscle Plasma.” By W. D. HAuuLiBurton, M.D., B.Sc., Assistant Professor of Physiology, University College, London. Communicated by Prof. E. A. ScHdrer, F.R.S. (From the Physiological Laboratory, University College, London.) Received May 24, 1887. The facts described by Kihne relating to the properties of the muscle plasma of cold-blooded animals are true in great measure for that of mammals. Admixture of muscle plasma with solutions of neutral salts prevents the coagulation of the latter. Dilution of such salted muscle plasma brings about coagulation; this occurs most readily at 37—40° C. Saline extracts of rigid muscle differ from salted muscle plasma in being acid, but resemble it very closely in the way in which myosin can be made to separate from it; myosin in fact undergoes a recoagu- lation. This is not a simple precipitation ; it is first a jellying through the liquid; the clot subsequently contracts, squeezing out a colourless fluid or salted muscle serum. This does not take place at 0° C.; it occurs most readily at the temperature of the body, and is hastened by the addition of a ferment prepared from muscle in the same way as Schmidt’s ferment is prepared from blood. The ferment is not identical with fibrin ferment, as it does not hasten the coagulation of salted blood plasma; nor does the fibrin ferment hasten the coagula- tion of muscle plasma. The recoagulation of myosin is also accom- panied by the formation of lactic acid. The proteids of muscle plasma are— 1. Paramyosinogen, which is coagulated by heat at 47° C. 2. Myosinogen,* which is coagulated at 56° C. 3. Myoglobulin, which differs chiefly from serum globulin in its coagulation temperature (63° C.). 4. Albumin, which is apparently identical with serum albumin a, coagulating at 73° C. : 5. Myo-albumose; this has the properties of deutero-albumose, and is identical with, or closely connected to, the myosin ferment. The first two proteids in the above list go to form the clot of myosin; paramyosinogen is, however, not essential for coagulation ; the three last remain in the muscle serum. * It is on the presence of this proteid that the power of fresh muscle juice to hasten the coagulation of blood plasma depends. 1887.] Dispersion Equivalents. 401 Paramyosinogen, myosinogen, and myoglobulin are proteids of the globulin class. They are all completely precipitated by saturation with magnesium sulphate, or sodium chloride, or by dialysing out the salts from their solutions. They can be separated by fractional heat coagulation, or by fractional saturation with neutral salts. When muscle turns acid, as it does during rigor mortis, the pepsin which it contains is enabled to act, and at a suitable temperature (85—40° C.) albumoses and peptones are formed by a process of self- digestion. It is possible that the passing off of rigor mortis, which is apparently due to the reconversion of myosin into myosinogen, may be the first stage in the self-digestion of muscle. XX. “Dispersion Equivalents. Part I.” By J. H. GLADSTONE, | Ph.D., F.R.S. Received May 24, 1887. The idea of refraction equivalents has become familiar to those who work on the borderland of optics and chemistry, and the value of that property as a means of investigating the chemical structure of com- pounds is becoming more and more recognised. There is a similar property, perhaps equally valuable for the same object, which has attracted little attention hitherto; I allude to the equivalent of dispersion. During the last twelve months, however, I have collated old measurements of the length of the spectrum, whether made by myself or by others, and have added many new determinations, and I am now in a position to submit some of the results to the Society. The history of the subject goes back to the first paper of Mr. Dale © and myself upon the refraction of light,* in which we gave as one of the conclusions ‘‘ the length of the spectrum varies as the temperature increases.” In our second papert we came to the conclusion that “there is no simple relation holding good for different liquids between the increase of volume and the decrease of dispersion by heat,” con- trary to what we found to be the case with refraction. We adopted Pu—a, 2.2., the difference between the refractive indices for the Solar lines A and H asthe measure of dispersion. This divided by the density gave the specific dispersion. When, however, Landolt adopted the plan of calculating the “refraction equivalent,” we applied the same method to what we termed the dispersion equivalent, that is, ‘‘the difference between ue and P/ ot - or more simply * “On the Influence of Temperature on the Refraction of Light.” ‘ Phil. ‘Trans.,’ 1858, p. 8. t “On the Refraction, Dispersion, and Sensitiveness of Liquids.” ‘ Phil. Trans.,’ 1863, p. 323. 262 ee ra A402 Dr. J. H. Gladstone. [ June 16, pias» where d equals the density of the substance and P its d 4 y 3 atomic weight. In two communications made to the British Association,* we stated that the dispersion equivalent of any substance is little affected. by the manner in which it is combined with other bodies, and we gave as the mean value of CH, 0°35 in the vinic group, but higher figures in the benzene and pyridine groups; phosphorus equal to 2°9; chlorine 0°5; bromine 1°3; and iodine 2°6. In my subsequent paper in the ‘ Philosophical Transactions,’} in which the refraction equivalents. of forty-six elements were worked ont, I remarked, “the question of dispersion equivalents is also of interest; the data for the investigation of the matter are given in the Appendix.” But there the matter rested. The paramount interest of the refraction equivalents in truth caused both the Continental observers and myself to neglect the question of dispersion ; and with the exception of brief references to: it in papers on Refraction,{ nothing was published on the subject till last summer, when I applied the measurement of dispersion to the elucidation of the chemical structure of the essential oils;§ and afterwards in a paper at Geneval| I ventured to give approximate values for fifteen elements. Almost simultaneously with these appeared a paper by Brihl,§ in which he endeavoured to eliminate the influence of dispersion from the refraction equivalents of highly refractive bodies. In this he seems to establish the fact that for such bodies at least, the theoretical formula of Lorenz, gives more uniform results than the pe—l (w+ 2)d empirical formula “ =: but he draws as one of his conclusions, “the dispersion exercised by different bodies stands in no relation which is as yet clearly recognisable and measurable either with the refraction exerted by them, or with the chemical nature of the sub- stances.” In this and a following paper** he gives additional proof of the worthlessness of Cauchy’s dispersion formula, or any of the suggested modifications of it, to eliminate the influence of dis- persion. It will be seen that Brihl’s conclusion is inconsistent with the views I have recently expressed, and the determinations I had already * ‘Brit. Assoc. Rep.,’ 1866. (Trans. Sec., pp. 10 and 37.) + “On the Refraction Equivalents of the Elements.” ‘ Phil. Trans.,’ 1869, p. 27. ft ‘Phil. Mag,’ vol. 11, 1881, p. 59. ‘Brit. Assoc. Rep.,’ 1881 (Trans. Sec., p. 591). ‘Chem. Soc. Journ.,’ vol. 46, 1884, p. 258. § ‘Chem. Soc. Journ.,’ vol. 50, 1886, p. 609. || ‘ Archives Sci. Phys. Nat.,’ vol. 16, 1886, p. 192. “| ‘Liebig’s Annalen,’ vol. 235, 1886, p. 1. ** ‘Tiebig’s Annalen,’ vol. 236, 1886, p. 233. 1887. | Dispersion Equivalents. 403 published; but while Iam free to confess that there are many diffi- culties in the investigation of dispersion which have not been felt in dealing with refraction, I hold that the following conclusions are fully warranted by the data :— Ist. That dispersion, like refraction, is primarily a question of the atomic constitution of the body; the general rule being that the dispersion equivalent of a compound is the sum of the dispersion equivalents of its constituents. 2nd. That the dispersion of a compound, like its refraction, is modified by profound differences of constitution; such as changes of atomicity. 3rd. That the dispersion frequently reveals differences of constitu- tion at present unrecognised by chemists, and not expressed by our formule. In this paper my object will be to point out the uniformity that does exist, leaving apparent exceptions for future consideration. Before entering upon an attempt to determine the dispersion equivalents of the different elementary substances, it may be well to consider the difficulty which occurred at the threshold of the enquiry, and another which appears to have deterred Briihl from prosecuting his enquiries in the direction of dispersion. The original experiments of Mr. Dale and myself led to the belief that the “specific dispersion, eee slightly diminishes with in- crease of temperature”’; but more accurate experiments made on the Same specimens of bisulphide of carbon, benzene, brombenzene, and mint terpene, at the temperature of the observing room in the height of summer and depth of winter, have made me less confident of this conclusion. The variations are certainly within the limits of experi- mental error. The observations of Willner both upon bisulphide of carbon and water, those of Baille and v. d. Willigen upon water, as well as those of Pisati and Paterno on benzene and cymene, show that there is little, if any, appreciable difference in the specific dis- persion at different temperatures. The general tendency of the observations on the seventy substances which have been examined more or less carefully, appears to be that the small difference of specific refraction that exists at different temperatures is a little greater in the case of H than in that of A. Brihl gives three cases of isomeric or quasi-isomeric bodies. He measures the specific dispersion by the B of Cauchy’s formula divided by the density. He shows that cinnamic alcohol, C,H,,O, and . ¢cinnamic aldehyde, C,H,O, both of which he conceives to contain four pair of doubly-linked carbon-atoms, have a widely different specific dispersion ; that allyl paracresolate and anethol, C,.H,,.O, having four pair of doubly- linked carbon-atoms, are also quite different iu 404 Dr. J. H. Gladstone. [June 16,, dispersion; and that, on the other hand, cymol and hexahydro- naphthalin, both having the formula C,)H,,, but the first three pair, and the second two pair of doubly-linked carbon-atoms, have nearly the same dispersion. But if we reckon out the refraction equivalents. for cinnamic aldehyde and for anethol from the numbers given in the same table, it will be seen that they are inconsistent with the sup- position that these bodies have the chemical structure that he attributes to them; in fact the extremely high dispersion in each case only tells the same tale as the extremely high refraction. As to the two substances of the formula C,)H,, it is open to question whether hexahydronaphthalin has only two pair of doubly-linked carbon- atoms; and the refraction equivalent calculated for each of the specimens throws some doubt upon their purity. Brihl also com- pares methyldiphenylamine with cinnamic aldehyde, but the presence of nitrogen in the first body, and the uncertainty as to the constitu- tion of the second, render it unsafe to draw any conclusions from the comparison. That the specific dispersion of isomeric or polymeric bodies is practically the same, except where the constitution is very different (as in aniline and picoline), was shown in my paper in the ‘ Philosophical Magazine’ six years ago; and this must be set against the doubtful cases mentioned above. The Hlements. There are but few of the elements of which the dispersive energy can be directly determined; but it so happens that two or three of these are among the most dispersive of bodies. Phosphorus was determined by Mr. Dale and myself in a melted condition, and also by Damien both in that and the solid state. Our observation gives 3°1; those of Damien* work out at 2°9 and 2°8 respectively. Sulphur.—An old observation of mine on this body hquefied, gave 0°90 for E—A; and recent observations from its solutions in bisul- phide of carbon give 1:2 for F—A. These agree in indicating about 2°6 for H—A. Selenitum.—According to the observations of Sirks,+ the refractive indices for A and D are respectively 2°653 and 2:98; taking the specific gravity at 4°5, the dispersion equivalent of this element would be the extraordinary amount of 5°67 for D—A alone. Hydrogen.—Ketteler’s{ observations give a dispersion equivalent of 0°0152 for the difference between the green line of thallium and the red line of lithium. * ‘Journal de Physique,’ 1881. t+ ‘ Poggendorff, Annalen,’ vol. 143, 1871, p. 429. { ‘ Poggendorff, Annalen,’ vol. 124, 1865, p. 390. 1887. | Dispersion Equivalents. 405 Carbon.—Schrauf’s* observations upon diamond give 0°058 for the dispersion equivalent of the same range. Iodine, in the state of vapour, or dissolved in bisulphide of carbon, gives a spectrum in which the order of the colours is abnormal. Far more important results have been obtained from organic sub- stances, by following a method similar to that which Landolt adopted in his determination of the refraction equivalents of carbon, hydrogen, and oxygen. The materials for such an enquiry are very abundant. They consist of the observations published by Mr. Dale and myself in 1863, and my more recent determinations published and unpublished, the very valuable lists of Landolt and Briihl, numerous observations by Kanonnikoff, Nasini, and others. ‘The Continental observers have usually adopted the lines «, 8, and y of the hydrogen spectrum. On comparing the refraction equivalents of organic liquids of the fatty acid series which differ from one another by CH, or multiples of it, my best. determinations lie between 0°33 and 0°36, averaging about 0°35 for each CH,. On treating in a similar manner fifteen series of such bodies in Brihl’s tables, some of which contain many terms, the dispersion equivalent for y—« works out very uniformly at an average of 0'215. This answers to 0°342 for H—A. Armstrong’s cymhydrene, which is a saturated substance of the formula C,)H.), has a dispersion equivalent of 3°44, giving therefore 0°344 for each CH,. Kanonnikoff’s determinations of tetraterpene and naphthene, also C,H», give similar numbers. It may therefore be assumed that the value of CH, in saturated organic compounds lies between 0°34 and 0°35, answering to the well known 7°6 as the refraction equivalent of the same combination. When, however, we examine unsaturated compounds in a similar manner, we find that the value rises to at least 0°40. Hydrogen.—W hile the value of CH, may be fairly taken at 0°34, it is more difficult to say what portion of this is due to the carbon, and what to the hydrogen. I have endeavoured to determine it, by deducting » times CH, from the paraffines C,H»,,2; by comparing the monatomic, diatomic, and triatomic alcohols, and by other similar means. The results are somewhat irregular, as might indeed be expected from the smallness of the residual figure, but give a mean of 0-04 per each hydrogen. _ Carbon.—lf the H, in CH, be taken at 0:08, it follows that the carbon will have a dispersion equivalent of about 0°26. This answers to the refraction equivalent of 5:0. It is well known, especially from the researches of Brihl, that in unsaturated organic compounds, there is an increase of refraction, for * “Ueber das Dispersionsiquivalent von Diamant.’”? ‘ Wiedemann, Annalen,’ vol. 22, 1884, p. 424. 406 Dr. J. H. Gladstone. | [June 16, the line A, of about 2°2 for each pair of doubly-linked carbon-atoms. Assuming this to be due to a different value for carbon, we obtain a refraction equivalent of 5:0+1'1,7.c., 6:1. In all such cases there is a great increase of dispersion; this increase, however, is not always the same. In the allyl compounds, whether determined by Bruhl, Kanonnikoff, or myself, it is uniformly very close to 0°5. In the olefines it is the same. In the whole of the aromatic series it is at least 0°8. Coincident therefore with the higher refraction equivalent for carbon, we have two dispersion equivalents of about es 26+0°25, and 0°26+0°40, z.e., 0°51 and 0°66. It must remain for future consideration, whether there may not be an intermediate refraction equivalent, corresponding to the dispersion equivalent of 0°51. On the appearance of Briihl’s papers in 1880, I ventured to suggest that there was a still higher refraction equivalent for carbon, in those cases in which it “has all four of its units of atomicity satisfied by other carbon-atoms, each of which has the higher value of 6:0 or 6:1,” as in naphthalene or pyrene. This view has been, and is, the subject of controversy, but on turning to the dispersion equivalents of these bodies, they are found to be always enormously high, far higher than can be accounted for by the figures with which we have hitherto been dealing. Oxygen.—It has been established by Brihl, that in the case of aldehydes and ketones, oxygen has a refraction equivalent of 3°4. As these have the general formula C,H,,O, and the dispersion of CH) is known, it is very easy to determine the dispersion equivalent of the oxygen. Various determinations of these bodies give a fairly uniform result; viz., 0°18 for H—A. Tn the case of the alcohols, the oxygen has a refraction equivalent of only 2'8. Comparing the dispersion equivalents of the alcohols of different atomicities in the published lists, the mean value for oxygen in this condition comes out at about 0°10. Nevertheless, in the organic acids and compound ethers, the value of the two oxygens together seems rarely if ever to exceed 0:24. Chlorine.—Our lists also give us the méans of determining the value of chlorine in organic substances of the fatty acid series. As reckoned from such substances as chloroform, chloral, ethylene, and ethylidine chloride, and bichloride of chlorethylene, the dispersion equivalent of this halogen appears to be 0°50, though in the simple chlorides of the compound radicles it appears to be a little less. Bromine.—The dispersion equivalent of bromine varies in a similar way to that of chlorine. As deduced from bromoform and the dibromides of the olefines, it 1 is 1°22; but in the bromide of ethyl it is lower. Lodine.—The dispersion equivalent of iodine in di-iodide of me- 1887. | Dispersion Equivalents. 407 thylene was found to be 3°65, and in iodoform in solution it seems to be about the same; while in the ordinary iodides of the compound radicles it is much less. Nitrogen.—Nitrogen appears to have a lower value in nitriles, cyanides, and sulphocyanides than in organic bases: but the figures obtained so far, for each condition of nitrogen, are not accordant. The lower value, however, probably does not exceed 0:10. The values of NO, in the fatty acid series, as deduced from substitution products of the alcohols, glycerine, mannite, &c., are, however, fairly accordant, giving about 0°82. Sulphur.—For the determination of sulphur, we have the excellent observations of Wiedemann,* and Nasini;f the first on sulphur substitution products of carbonic ethers ; the second on many organic compounds. There exist also two or three observations of my own. It appears that the value of sulphur in mercaptans, sulphocyanides, and sulphides of ethyl, butyl, amyl, and allyl, is about 1°21; answer- ing to the refraction equivalent of 14:0. But in bisulphide of carbon, where the refraction equivalent of sulphur is 16:0, the dispersion equivalent is 2°61: and this is about the value which the element appears to have in the isosulphocyanides, while the element itself dissolved in bisulphide of carbon, gives 1:20 for the dispersion F}—A, which is equivalent to fully 2°5. These results are collected together in the following table. The dispersion equivalents here given must however not be taken for anything more than approximate. eigen Atomic Refraction Dispersion i Weight. | Equivalent A. | Equivalent H—A. Phosphorus .... sae o one 31 18°3 3°0 Sulphur, double bond ee 32 16:0 2°6 oe single bonds........ ; 14°0 1°2 PG GMO SOM S!. 35:3 Zee) a's wie gia. ald a's 1 1°3 0°04 EO tee sae oh ay. a sataleoieie4 «is 12 5°0 0°26 Petes dla dis! ehe a ots sca eis. +s %3 6:1? 0°51 MMe Mise n sae a's 66 ba 6-1 0°66 Oxygen, double bond ........ 16 3°4 0°18 aa single bonds.......: ss 2°8 0°10 WiMGrier icc des ec cc hase ee 35°5 9°9 0°50 EPROM) Gis glide edit ble elee sleiee 6 80 15°3 1°22 PONE pees se oy aitt/sisaishal joie) «yayelareiay « | vy Lee 24°5 3°65 MOEN ies wif buc'sisjsc0 6 se, #6, ¢ 14 4cl 0:10 eG a Sota Car CRIES gS eae 14 7°6 0°34 De estaba is ol /a’te 6 wididl'e le'xe’e 4.6 11°8 0°82 * ‘Journ. Prakt. Chem.,’ vol. 114, 1873, p. 453. + ‘Gazz. Chim. Ital.’ vol. 13, p. 296. 408 Dr. J. H. Gladstone. [June 16, It will be seen by a glance at this table, that the dispersion equiva- lents of the elementary substances are not in proportion to their atomic weights, or, in other words, that they have different specific dispersive energies. Thus the analogous elements, sulphur and | oxygen, are strongly contrasted in this respect, their specific refrac- tive energies being respectively 0°081 and 0°011. Again it will be evident that the proportion between the refraction and dispersion is not the same even in the case of analogous elements. Thus, taking the three halogens, the ratio between the refraction for A and the dispersion for H—A for chlorine is about 100 to 5, for bromine 100 to 8, and for iodine 100 to 15. Metals in Salis ——In 1869, as already stated, I suggested that the same data from which the refraction equivalents of the metals had been determined, would be available also for their dispersion equiva- lents. I have many observations in addition to the data then published ; and Kanonnikoff has been over part of the same ground, measuring the « and # of the hydrogen spectrum. Unfortunately, however, the errors of observation bear so considerable a proportion to the whole amount observed, at any rate in dilute solutions, that we cannot look upon single determinations of the dispersion equiva- lent of a salt as of much value. Thus, even when great care has been taken in measurement, each index of refraction is liable to an error of +0:°0001, and as the error in determining A and H may be in opposite directions, #,;—, cannot be relied upon within +0°0002. Now among solutions of salts the specific dispersion rarely amounts to U-02 ; the error of observation may therefore be more than 1 per cent., and if the salt should form only 5 per cent. of the solution, the error might exceed 20 per cent. Such solutions, therefore, are practically valueless for this purpose. Yet it would be easy to publish a table of miscellaneous salts, the dispersion equivalents of which had been deduced from several fairly accordant observations on fairly strong solutions, or which have been corroborated from some independent source. It has appeared preferable, however, to confine attention at present to the series of potassium and sodium salts, which are far the most complete and the most instructive. It is evident at a glance, that the figures in the sodium cglanusks are invariably lower than those in the potassium columns, and that the difference is fairly uniform. In regard to the refraction equivalent, it is about 3°33,* and in the dispersion equivalent it is about 0:09. It follows, that if we can determine the value of potassium, that of sodium may be at once calculated: and presumably the same process may be extended to all other metals that form soluble salts. But it is not so easy to determine the value of potassium. In * Previously determined at 3°3. 1887. | Dispersion Equivalents. 409 Refraction Equivalent. Dispersion Equivalent. Potassium.! Sodium.| Difference. || Potassium.| Sodium.| Difference. Chloride... 18°83 15°40 3°43 1 gare 1°18 0:09 Bromide... 25°25 21°80 3°45 2°17 2°08 0:09 fodide....). . 35°78 32°52 3°26 4. *4.2 4°33 0:09 Hydrate... 12°60 9:26 3 ‘34 0°79 0°72 0:07 Formate... 20°01 16°60 3°41 1:07 0:96 O'll Acetate.... 27-52 24°34 3°18 1°32 1°28 0:09 Carbonate..| 28°63 22°17 | 2(3°23) 1:40 1°34 2(0 03) Oxalate.... 37°55 ape ere 2°18 Nitrite .... 18°99 15°65 3°34 1 °30* LT 0°13 Cyanide ...| 17°18 vc af 0-94. regard to the refraction equivalent, my original determination was 8:1; but Kanonnikoff gives only 7°75, which led me, three years ago, to recalculate the observations, taking Brihl’s values for oxygen, and to reduce my previous estimate to 7°85. This is determined mainly from the organic salts, and the nitrate, and cyanide. I did not draw any conclusion from the haloid salts, as the chlorine, bromine, and iodine in them appear to have somewhat higher values than what they have in organic compounds. How are we to determine the corresponding equivalent of disper- sion? From the haloid salts it would seem to be about 0°8, but it seems likely that the disturbing influence, whatever it be, which increases the refraction of the haloid salts, would affect the dispersion. The formate and acetate, KCHO, and KC,H30,, pro- mise more trustworthy results, as we can subtract from their dispersion equivalents the numbers already determined for carbon, hydrogen, and oxygen. This will give respectively 0°53 and 0°44 for the dispersion equivalent of K. If we view potassium hydrate, KHO, as water in which one hydrogen atom is replaced by potassium, water being 0'265, we obtain the value of 0°565 for K. From the nitrite, KNO,, by subtracting 0°82 for NO,, we obtain 0°48 for K. In like manner from the cyanide KCN, by deducting 0°36 for cyanogen, we get 0°58 for K. From the carbonate, K,CO;, by taking the probable value of the CO, at 0°60, we get 0°40 for each K. From the oxalate, K,C,0,, by deducting 1:00 we get 0°59 for each K. | These figures, varying from 0°40 to 0°59, are too uncertain, and too * This is estimated from measurements of A, F, and G, and is somewhat open to doubt, as there seems to be something abnormal in the spectrum. 410 Messrs. J. J. Thomson and H. F. Newall. [June 16, wide to give a good average. I doubt if such variations can be attributed wholly to experimental error; but on the other hand, it is difficult to imagine that potassium should have more than one dispersion equivalent, while in the same series of dissolved salts it has apparently one and the same refraction equivalent. I am more disposed to believe, that the uncertainty lies in the value of the radicles to which the metal is joined; but this will require a more extended research. It is also an important enquiry :—To what extent does the modifica- tion of the dispersion equivalent affect the refraction equivalent for the line A? On this question, and others of a similar nature, I hope shortly to submit a further communication. I think it will be already sufficiently obvious that the specific dispersive energy of a compound body is a physical property analogous to, but distinct from, its specific refractive energy, and that it is capable in like manner of throwing light upon chemical structure. XXI. “On the Rate at which Electricity leaks through Liquids which are Bad Conductors of Electricity.” By J. J. THomson, M.A., F.R.S., Fellow of Trinity College, and Cavendish Professor of Experimental Physics in the University of Cambridge, and H. F. Newaun, M.A, Assistant Demonstrator in Physics, Cambridge. Received May 26, 1887. The experiments here described were undertaken to test whether the rate at which electricity leaks through a liquid which conducts electricity badly, does or does not follow Ohm’s law. The method used is described later on; it consists in establishing by a battery a difference of potential of about 100 volts between the plates of a condenser, in which the dielectric is the faulty insulator to be experimented on, then disconnecting the battery, and measuring with an electrometer the rate at which the difference of potential dies away. Let v, and v, be the differences of potential at the beginning and end of an interval T, and let “l= «. oy If c be the capacity of the condenser, q the quantity of electricity which has leaked away in the time T, then pe V1 — Vo — ae 1887.| Rate at which Electricity leaks through Liquids. 41t so that 1 = ¢(x—1). 2 The rate of leak = q/T, so that rate of leak C {ference of potential at the end of the interval rau (a—1) = &, say. Now if the conduction follows Ohm’s law, = will be constant; hence Ohm’s law will be obeyed if « be constant. The tables given later on show how nearly constant ~ is. To test the accuracy of the law, we have— oo bh 0% 0x & Soe. we, Sea so that a change of 1 per cent. in x will correspond to a change of z—1/z per cent. in =, and a deviation from Ohm’s law to this extent. The liquids tried were benzene, olive oil, carbon bisulphide, and paraffin oil. We could detect no deviation from Ohm’s law for the first three of these substances, though the difference of potential fell from 500 scale divisions to 20. Mor paraffin oil, however, the con- ductivity seemed slightly greater when the difference of potential was large than when it was small. The departure from Ohm’s law even in this case was small. Quincke* has found that when the H.M.F. is comparable with that which would cause a spark to pass through the liquid, Ohm’s law ceases to be even approximately obeyed. Thus, for carbon bisul- phide, when the E.M.F. was 29°21 C.G.S. units, the current was 6:2; when the E.M.F. was 47:74, the current was 36; showing that with large electromotive forces the current increases much more rapidly than the E.M.F. | With the small electromotive forces which we used, the current, however, is proportional to the H.M.F’., showing that when the H.M.F. is‘comparable with that required to produce a spark through the liquid, other methods of dissipating the energy of the electric field must exist besides those which are active in conductors conveying a current according to Ohm’s law. We found that carbon bisulphide showed a phenomenon analogous to electric absorption, the only case we know where this has been observed in a liquid dielectric. The conductivity of all the liquids on which we experimented increases as the temperature rises, so that in this respect they behave like electrolytes. te * “Wiedemann, Annalen,’ vol. 28, p. 529. 412 Messrs. J. J. Thomson and H. F. Newall. [June 16, Description of Apparatus. The condenser consisted of two copper cylinders, the outer one being formed into a pot 12 inches deep and 4 inches in diameter, closed at the bottom by a rounded end carefully worked inside, the inner one, 8 inches long and 3 inches in diameter, being closed, rounded off at both top and bottom, and carefully worked outside. The outer cylinder was held in position on a bracket attached to a brick wall, and was always connected to earth through the gas-pipes; the inner one was suspended by a silk thread, 5 feet long, also from a — bracket on the wall, vertically above the first, and was connected to an insulated mercury cup by means of a thick wire, which was care- fully soldered into the top of the cylinder, and bent into a loop to attach the silk thread to. The figure shows the arrangement in eleva- tion, the outer cylinder being represented as transparent, to show the inner cylinder and attachment. The liquid to be experimented on was poured into the outer pot, and the inner cylinder was lowered into it, both being set vertical by means of a plumb-line. It was found necessary to load the inner cylinder with shot to keep it sunk in the liquid. The suspension by a single silk thread was found very satisfactory, as it insulated well, and avoided the introduction of solid dielectrics, and the suspended cylinder if disturbed came again to rest after a very few oscillations. The condenser was charged by means of a number (varying between 20—80) of Post Office Daniell cells, and Thomson’s quadrant electro- 1887.] Rate at which Electricity leaks through Liquids. 413 meter (White’s form) was used to show the fall of potential as the charge leaked through the faulty insulating liquids. To facilitate changes of connexion between the condenser, the electrometer, and the cells, a paraffin block, with holes bored through it and filled with clean mercury, was used. The whole arrangement of apparatus was as shown in fig. 2. yer of fore Mercury Airy. a a SEN PUM CLUS | \ Ls ain pp x dd) scale — 4 - Curve plotted for olive oil from Table XII. Time of charging condenser short. Hzperiments on Rate of Leak at Different Temperatures. In all the liquids experimented on (benzene, olive oil, carbon disul- phide) the leak was quicker at higher temperatures than at lower. These liquids then must be classed in this respect with electrolytes, and not with metallic conductors. A metal vessel was put round the outer cylinder of the condenser, and was connected by a tube with a second vessel, which could be heated or cooled, and raised or lowered. By these means the condenser could be surrounded by hot or cold water without having its position disturbed in any way. Readings were then taken at 15. seconds intervals, the condenser being in one set of observations under the same circumstances in every way except with respect to temperature. Hach set contained three (or five) readings, one reading at a high or low temperature being taken between two readings at a medium temperature, so as to 1887.] Rate at which Electricity leaks through Liquids. 423, show that no permanent change had taken place by the raising or lowering the temperature of the leaking dielectric. Benzene—Tables XIV—XVIII give the readings for benzene at: the temperatures specified at the head; and fig. 8 shows the tables graphically. Benzene at different Temperatures. Table XIV. Table XV. Table XVI. Table XVII. Table XVIII. Temp. 10°8°C.| Temp. 22°C. | Temp. 11:4°C. | Temp. 5°4° C. | Temp. 8°2° C. 490 4-49 490 4-46 490 4-10 490 490 4.19 435 i 421 " 44,4, : 482 4.44: ; Ua 1°15 1°09 1°09 Bas. an. 365: 5 | AO 476 4070 1-11 1°16 : 1°09 1:09 356 ; 315 : 369 ; 471 374 1:10 1°15 Eee Eee) 1°08 324 : 272 , 3390 a 465 345 : 10 22 ERENG 1°09 1°08 295 , 235 ; 306 d 460 318 ; 1°10 1°15 11k) r 1-09 267 f 204 , 278 : 457 292 3 1°10 6 aoa, 1:09 1°09 243 : 175 : 254: ; Benzene par- |. 268 k SL. 1°16 1°10 = 1-08 219 : 151 231 : tially frozen 247 : 1°08 1°10 5 1:08 202 , 210 F in the 228 AG 1°10 : 1°10 1:09 183 : 192 : condenser. 210 4 1-09 1°10 1:09 168 é 175 4 193 : 09 LO Ss 1:09 154 3-40 158 4.10 177 G9 140 143 163 Ratios— Mean.. 1°10 EAST 1°097 ee 1:088 Max...1°12 1°17 ALN) 5c L110 Min. ..1°08 1°15 1°09 ave 1:08 Curves plotted for benzene at different temperatures from Tables XIV, XV, XVII, and XVIII. Dotted curve for benzene partially frozen in condenser. 424 Messrs. J. J. Thomson and H. F. Newall. [June 16, In the tables the values of the ratios have been put down, and they will be seen to be fairly constant in each table. Table XVII contains readings for benzene at 5°4°; the leak was so slow in this case as to attract attention, and it was found that the benzene was partially frozen; hence the curve in fig. 8 is dotted to show that the benzene was in a different state. The curve corresponding to Table XVI would come very close to that corresponding to Table XIV, and is therefore omitted from fig. 8. Carbon Disulphide-—Tables XIX—XXII give the readings and ratios for carbon disulphide at different temperatures. Carbon Disulphide at different Temperatures. Table XIX. Table XX. Table XXI. Table XXII. Temp. 9°8° C. Temp. 19 -2° C. Temp. 4°4° C. Temp. 8°6° C. 500 1:06 500 1°08 500 1-05 500 1:05 472 ; 463 475 ae 474, 1°06 1:07 1°05 1°06 447 pave 430 ; 452 ; 450 : 1°05 1°08 1°05 1°06 425 : 398 P 431 425 : 1°06 1°07 1°05 1°05 402 : 370 ; 412 ‘ 4.04: f 1°06 = 1°07 1°05 1°05 380 ; 345 ie 391 , 383 : 1°06 1°07 1 ‘04 1°06 360 y 320 : 374 WS 362 , 1°06 L307, 1°05 1°05 341 : 298 : 357 : 345 f 1°05 1:07 1°06 1°06 325 2 276 t 339 : 327 ‘ 1°06 1 OV 1°04 1°06 307 257 j 325 rf 310 5 1°05 1:07 1°05 1°08 292 Ar 239 é 310 : 295 : 1°05 1:07 z 1°04 1°06 277 223 296 279 1°05 1°07 1°05 1°06 264 3 208 281 , 264 ae 1°04 1°04 1°05 250 269 4 251 - 1.05 1°05 1°06 238 F 256 236 : 1°05 1°05 1°05 226 : 244, ‘ 224 : 1°05 1°04 Sets BIE Sa 05 Soe L204 213) ee 204. 224 : 201 1°06 211 1:05 201 Ratios— ; Mean .... 1:058 1:071 1-052 1 +055 Max. 1°06 1°08 1°06 1-06 1887.] Rate at which Electricity leaks through Liquids. 425 sEEeeOSESenaae ra G Pol: ilo gif oi the Teer erry a ENA VAATEN A AZ STALTUC ULE Wi APTZAPE V Z ae pY4 Lf JARS ee ———E Curves plotted for carbon bisulphide at different temperatures from Tables XIX, XX, and XXI. A curve plotted from Table XXII would almost coincide with that from Table XIX. In fig. 9 the curve from Table XIX is practically the same as that from XXII; the latter is therefore omitted. Olive Oil—Tables XXITI—XXVIII give the readings and ratios for olive oil, and fig. 10 shows graphically the first three of these tables. Olive Oil at different Temperatures. Table XXITI. Table XXIV. Table XXV. Temp. 11°5° C. Temp. 47 °5° C. Temp. 18°5° C. 44.4. E 394 5 1°10 ? 390 4 z 1°23 403 2°36 319 : 1°10 165 " 1°53 364: \ 2°54 260 ! 1:10 65 1°24. 332 4 210 b 1:10 1°24 301 : 168 1:10 273 11 ja 0) 247 1°10 BAS me AAV 203 Ratios— Mean i ion 0) 2°45 1 °236 Max 1:10 2°54. 1°24. Min 1:10 2°36 223 426 Messrs. J. J. Thomson and H. F. Newall. [June 16, Table XX VI. Table XXVIT. Table XXVIII. | Temp. 10° C. Temp. 31° C. Temp. 12° C. 490 ? 1°13 pis eo 490: ae 433 2 321 : 422 1°13 1°49 1°16 382 : 215 363 1°14 fies 5. 336 : 315 1°15 1°16 298 ‘ 270 1-12 1°14 265 i 235 1°13 1°15 233 1-12 205 116 207 17%, Ratios— 41 “156 Mean.. 1°134 Tol 1°16 Maxie. 16 | 1°53 (1°14 Mima? $601 712 1°49 eee ame meta Curves plotted for olive oil at different temperatures from Tables XXIII and XXYV. The dotted curve is got by a process of interpolation roughly from Table XXIV. 8 e+ eee | At the higher temperatures the rate of leak was so great that there is some doubt as to the first reading of the deflection: hence the discrepancies in the values of the ratios. Tables XXIV and XXVII are abridged from fuller tables which give readings taken at 15 seconds intervals. These are given below. 1887.] Rate at which Electricity leaks through Liquids. 390 290 220 165 125 90 65 at feed fd pet fet fed Table XXIV. | Temperature 47°5° C. wo oo co co co Go ~The Table XX VII. 4.90 423 369 321 282 246 215 189 ft feed fed et bd fet fed Hzperiments with Higher Electromotive Forces. “15 15 ‘15 "14 15 "14 “14 Temperature 31° C. 427 In the experiments dealt with so far the battery used to charge the condenser was one of 20 silver chloride cells, hence of electromotive force of about 20 volts. For electromotive forces between 20 volts and zero Ohm’s law is shown to hold good for the liquids experi- mented on. By the following experiments the limits were extended to between about 100 volts and zero. The condenser was charged to about 100 volts, and readings were taken at intervals of 15 seconds, the electrometer having been reset so as to be less sensitive. The ratios are, without any obvious reason, less regular than in the earlier experiments. Deflections. Ratios. Deflections. 490 x 201 437 Le 173 = das td fs 395 113 150 349 1:14. 130 305 1‘15 115 265 7 ve 101 234. 1:16 90 Ratios— Mean Maximum RRSP TELE yg elem se 5 ae om Table X XIX. Experiment 103. Olive oil. Charged to about 100 volts. eeere reece ee sere eeree Ratios. Pet fed et et RE Defiections. Ratios. Pe "13 15 a 8 13 13 14. ‘18 | | | | 428 Rate at which Electricity leaks through Liquids. [June 16, Table XXX. | Experiment 108. Olive oil. Charged to about 100 volts. Deflections. Ratios. Deflections. | Ratios. | Deflections. Ratios. toe 1°25 ge 1:21 40 1°17 160 73 34 ; 1°23 1°20 1°21 130 s 60 a 28 108 : 49 nee 23 1-22 1°22 1-07 1°21 19 Ratios— Mean Sec ae ee ss wae soe ued (Wia xiii (saree cercic-« «ve oie 1°25 NAnimuni see ae ccs Ley Experiments on Residual Charge. — Carbon disulphide showed peculiarities in the above experiments. With a short and sudden charge the rate of fall of potential was much quicker at the beginning than at the end of the readings. This is what would be expected if tkere were electrical absorption, part of the fall being due to true leaking, part to absorption. If the rate of leak is according to Ohm’s law, the ratio curve for such a liquid would be inclined to the horizontal at first, but the inclination would diminish with time. This is what is found in the case of carbon disulphide when the condenser is charged for a short time. Again, the condenser, with carbon bisulphide between the cylinders, was charged for a time, then quickly discharged, and its inner cylinder connected with the electrometer. The deflection was at first connex- ion zero, then shortly rose to a maximum value, and finally diminished again after some time to zero. If the condenser was charged with opposite sign, the deflection from zero was in the opposite direction, If the condenser was charged first with one sign and then with the other, the deflections from zero were much smaller, but they appeared in the sense expected from residual charge phenomena. These effects were greatest just after the CS, had been redis- tilled, but at times were totally absent. The still was cleaned, but the effects after fresh distillation were as marked as before. Attempts to increase the effects by rendering the liquid less homo- geneous were successful, for heating or cooling the condenser un- equally always exaggerated the deflections. The following readings are a sample of numerous experiments :— 1887.] - The Brachial Arterial Arches in Birds. 429 0’ Q” Condenser connected to battery. 0 30 Condenser quickly discharged and connected with electro- meter. ; Reading on scale ¢.’. 6.2... 539 bi8 PE a aaa 615 maximum 2 vO Set. on Se BY / wn 0 Be epee Se | a .. 544 Other liquids were tested in this way, but in no other case were similar phenomena observed. Mixtures of CS, and benzene or paraffin were also inactive in this sense, even when the mixtures mere incomplete and the liquids were putin in such a way as to be “‘ streaky,” as was found possible. Some attempts were made to discover traces of polarisation, but no definite results were obtained. In the earliest experiments something of the kind was observed, but this was traced to the key and con- nexions. XXII. “The Development of the Branchial Arterial Arches in Birds, with special Reference to the Origin of the Sub- clavians and Carotids.” By JoHN YULE Mackay, M.D., Senior Demonstrator of Anatomy, University of Glasgow. Communicated by Professor CLELAND, M.D., F.R.S. Re- ceived May 29, 1887. (Abstract.) According to the theories of Rathke, which are universally accepted at the present day, the subclavian artery is supposed to take its origin from the aortic root or fourth embryonic branchial arterial arch. In the adult bird the subclavian on each side is found springing from the extremity of an innominate artery along with the common carotid: It is presumed that the right subclavian has been, by a shortening of the aortic arch, carried forwards until it meets and fuses with the base of the common carotid artery ; and the left subclavian is regarded as representing by its basal portion the fourth left arch or left primitive aorta. ‘T'he'subclavian of birds is thus regarded by Rathke as being developed in a manner similar to that of mammals. The author points out, however, that there is a marked difference in the rela- tions of the artery to the surrounding parts in these two groups. In mammals the subclavian artery is pe on its ventral aspect by the jugular vein and the pneumogastric nerve, and the recurrent branch of the latter turns round it upon the right side, but in birds the nerve 430 Dr. JY. Mackay. [June 16, and vein are dorsally placed as regards the artery, and the recurrent laryngeal nerves turn round the ductus arteriosus or vestiges of the fifth arches, a relationship which cannot be accounted for by supposing with Rathke that the vessel takes its origin first from the aortic root, because, if so arising, it would occupy a position dorsal to vein aud nerve, and it is impossible to imagine a method by which the — artery could pass from the dorsal to the ventral aspect of these struc- tures without cutting them through in its course. VV. Ventral vessel. S!. Subclavian of Mammals. DV. Dorsal vessel. S?. Subclavian of birds. In these circumstances the author has undertaken an investigation into the manner in which the subclavian artery first makes its appear- ance in birds. He finds that it occupies from the first a ventral posi- tion arising from the truncus arteriosus at the ventral end of the third arch. The vessel may be seen in the freshly removed embryo duck or chick on the third or fourth day, at a time when the pectoral limb is merely a small projection from the body-wall, and on the fifth day in the chick it may, while still filled with blood, be traced by the eye from the ventral end of the third arch across the superior cardinal vein to the limb. The presence of this ventral vessel is also demon- strated during the third, fourth, and fifth days in the chick by micro- scopic sections of hardened embryos, but, owing to the oblique course which the artery holds in the body-wall, it is impossible in one series of sections to trace its entire length, and this is probably the cause 1887. | The Brachial Arterial Arches in Birds. 431 of its having been overlooked by previous observers. In chicks at the close of the sixth day and in older forms it is pointed out that the artery may be followed by dissection under water. The innomi- nate artery has been observed to be formed, not by the gradual fusion of the subclavian and carotid arteries at their bases, but by the splitting up of the truncus arteriosus into canals continuous with the three permanent arches, the innominate artery belonging to the third, and the basal portions of the aorta and pulmonary artery to the fourth and fifth respectively. The author has also examined the relations of the subclavian artery in the different groups of vertebrate animals, and finds that instead of there being but one artery prolonged into the limb, as Rathke held, there are in reality two such vessels. One is represented by the mammalian subclavian, and also in lizards and amphibians is found arising from the aortic root, and passing outwards to the limb dorsal to the pneumogastric nerve and jugular vein. The other, present in birds and in crocodilian and chelonian reptiles, arises from the ventral end of the third arch, and crosses outwards ventral to vein and nerve. In most of the lower forms representa- tives of both vessels are present, and one or other is specially enlarged and supplies the greater part of the limb, but it is pointed out that in the forms where the two vessels co-exist they anastomose with one another in the body-wall at the base of the limb. This anastomosis may be dissected out in lizards, where the dorsal vessel is specially enlarged, and in crocodilian reptiles, where the ventral artery plays the important part. In the higher forms (birds and mammals) one of the arteries alone is present, but the cetacean group of mammals forms an exception to this rule. In this group both arteries are to be found, and it is the veutral, not the dorsal as in mammals generally, which specially supplies the limb. With reference to the development of the carotid artery in birds, Rathke believed that the external carotid was the prolongation of the ventral trunk from the extremity of the third arch towards the head, and regarded the branches of the external carotid as derivatives of this ventral vessel. The internal carotid he looked upon as represent- ing the third arch and its dorsal continuation towards the.head, while the common carotid was believed by him to be the portion of the ventral vessel between the third and fourth arches. It is pointed out that if the observations already explained as to the origin of the subclavian artery be accepted, and that’ vessel be held to arise from the ventral extremity of the third arch,¢then, if Rathke’s theory of the external carotid be true, the subclavian should be found in the adult as a branch of the external carotid; but this is not the case. The common carotid artery, which Rathke regarded as a ventral VOL. XLII. 21 i q . 432 The Brachial Arterial Arches in Birds. [June 16, vessel, runs towards the head in the adult bird, upon the dorsal aspect’ of the alimentary canal, and distributes intervertebral branches as it goes. Rathke believed that this artery was originally ventral in position, and passed gradually round the cesophagus in the course of growth until it finally reached the dorsal aspect; but the author points out that while the artery does change its position somewhat, it is to a much more limited extent than Rathke believed. In the chick of the third or fourth day, the main vessel for the supply of the head is the dorsal continuation from the third arch, the ventral vessel being small. The examination of the further development by sections and dissections makes it evident that the ventral vessel dwindles in importance, and becomes finally a small branch passing from the subclavian to the ventral aspect of the trachea, while the dorsal prolongation becomes the sole supply of the head. At the close of the sixth day the dorsal connexion between the ends of the third and fourth arches is still present, and it is continuous with the common carotid, which may be easily followed to the head as a dorsal vessel, and its external branches, as well as its internal, are therefore: to be regarded as derivatives of a dorsal stem. In the adult the common carotid lies in the middle line of the neck in contact with its fellow of the opposite side, but in the embryo the vessels of opposite’ sides are at some little distance from one another ; by the seventh day, however, they have approached one another so as to be almost in con- tact. This change, however, is not, as Rathke supposed, the passage of a ventral vessel to a dorsal position, but a slight alteration in the line of a vessel already dorsal. When the carotid system of different groups of vertebrate animals is examined, it is found that in those forms where, on account of the: preservation of the dorsal connexion between the third and fourth arches, the continuous dorsal longitudinal vessel can be traced, the branches for the supply of both internal and external aspects of the’ head arise from this dorsal vessel. In these forms the ventral pro- longation supplies only the tongue. This is the case in most lizards. As the higher stages are reached the disappearance of the portion of the dorsal vessel between the ends of the third and fourth arches. makes a comparison of the vessels uncertain, but the author has dis- covered in the crocodile, and as an abnormality in a guillemot, solid cords stretching between the common carotids and aorte on the dorsal aspect of the alimentary canal. In these cases it is seen that the greater part of the common carotid is to be regarded as the dorsal prolongation from the third arch towards the head. The ventral vessel in birds and crocodiles is not, therefore, the external carotid, as Rathke has it, but an artery running upon the trachea and supplying branches to the muscles on the ventral surface of the neck. 1887.] On Radiation from Dull and Bright Surfaces. 433 XXIII. “On Radiation from Dull and Bright Surfaces.” By J. T. Bortomury, M.A., F.R.S.E. Communicated by Sir W. THomson, Knt., F.R.S. Received May 26, 1887. In connection with an investigation on heat radiation which I have been carrying on for some time past, and on which I recently pre- sented a communication to the Royal Society, I have had occasion to examine the important results obtained by Mr. Mortimer Evans on the radiation of light and heat from bright and dull surfaces when incandescent (‘ Roy. Soc. Proc.,’ vol. 40, 1886, p. 207); and I have repeated and verified some of his experiments. Mr. Hvans experi- mented on carbon filaments of incandescent lamps; and in calculating, for my own use, the resistances of the filaments at different degrees of incandescence I was led to an unexpected result, and hence to an investigation of which I desire just now to offer a preliminary notice. In order to explain, it is necessary for me to state briefly the object and nature of Mr. Hvans’ experiments. Their object was the com- parison of the radiation from surfaces having a bright, polished appearance with that from dull surfaces having the appearance of lampblack; and he was led to an important practical conclusion as to the superior light-giving efficiency of the brilliant-looking filament. For these comparisons the same filament was treated in such ways as to alter the surface from dull to bright and back again. It was taken out of the glass globe for the purpose, and after treatment placed in a fresh globe, which was then exhausted. The lamps thus constructed and reconstructed were tested at various candle-powers, the energy for each candle-power being determined. The tables given in Mr. Evans’ paper show for the filaments in different conditions the potential and the current required to maintain different candle-powers from four candles upward. Using his numbers, and supposing Ohm’s* law to hold for the carbon filaments, I have calculated the resistances of the filaments at different candle-powers. Two filaments used by Mr. Hvans afforded satisfactory data for my calculations. They are designated in his paper D, DD, DDD, and C, CC, CCC. They had been treated in the following manner :—The filaments D and C were ‘‘ flashed” so as to have a dull surface with the appearance of lampblack. DD and CC are the same filaments flashed so as to have a brilliant surface, which, though black, has something of the appearance of frosted silver. DDD, CCC, are the same filaments again rendered dull as at first. The following table shows the volts, amperes, and calculated resistances at the candle- powers given in the left-hand column :— * T have already commenced an investigation into the question of the conformity of carbon filaments at different temperatures with Ohm’s law. pM apy: 434 Mr. J. T. Bottomley. [June 16, Table I—Carbon D. Di DD. DDD. Candles. | Volts. | Amp. | Resist.| Volts. | Amp. | Resist./Volts. | Amp. | Resist. =: 46°5 | 1°02 | 45°6 | 37°3 | 1 37°3 | 34 1°28 | 26°6 10 52°5 | 1°20 | 43°8 | 42 1°13 | 37°17| 38°5 | 152 2acs 20 58°3 | 1°40 | 41°6 | 47°8 | 1°32 | 36°29) 43 1°77 | 24°3 40 65 1°62 | 40°1 | 52°5 | 1°53 | 34°3 | 48 2°06 | 23°3 50 68 1°70 | 40°O | 54°2 | 1°60 | 33°9 | 50 2°12 | 23 °6* | | Table I1.—Carbon C. C. CC. . CCC. Candles. | Volts. | Amp. |Resist.| Volts. | Amp. |Resist. |Volts.| Amp.| Resist. A 45 | 0°86 |52°33| 34 | 0°95 | 35°79] 39 1°16 | 33°62 10 56 | 1°12 |49°99|} 39 | 1°12 | 34°82] 44°5 | 1°38 | 32°24 20 62 | 1°28 |48°43| 44 | 1°28 | 34°37] 49°5 | 1°53 | 32°37* Now if we suppose the resistance of the carbon filament to depend on the temperature, the resistance diminishing as the temperature increases (though very probably not in simple proportion) ; and if (as we should do in the case of a metallic wire) we use these resistances in order to compare the temperatures of the filaments at different candle-powers, we are led to a remarkable result. Taking the fila- ment D and dividing the resistances of D, DD, and DDD at four candles by those at the higher candle-powers, we obtain numbers, which may be looked on as ratios of conductances, and which may be taken as indicating, though not exactly representing, corresponding changes in the temperature of the carbon. Table III. D. DD. DDD. To pass from— increase of con- 4: candles to 10 candles ae aiid a \ froml1lto| 1:041 | 1°006 | 1:°047. me Cikeyy toi eh i i 1-096 | 1-028 | 1-095 RS Big Pr ace A 1137 | 1-087 | 1-137 a aeage RR anet és o 1714 | 1°100% = * The two results which appear last in these tables seem anomalous, and therefore I have not used them in my calculations. 1887.] On Radiation from Dull and Bright Surfaces. 435 The filament C gives confirmatory results, but unfortunately it seems to have broken down early in the condition CCC. I find, however,— Table IV. C. CC. CCC. To pass from— : 4 candles to 10 candles Ba 7 } from1lto| 1:047 1 ‘028 1-043 A, fi 74 0 akan a8 i 1 ‘081 1°041 a Comparing these numbers we are led to the result that, if we admit the assumptions I have made, the temperature to which the carbon must be raised in order that it may give out light of a definite candle- power is higher when the surface is in the dull condition than when it is in a brilliant metallic-looking state. This result was to me so unexpected that I proceeded to test it directly by the following experiments:—Two glass tubes, similar in every respect, were constructed, containing two precisely similar platinum wires cut from the same hank, which had been specially drawn for me some months before by Messrs. Matthey and Johnson. One of the wires was in its natural bright condition, while the other was covered with the thinnest possible coating of lampblack, which was put on by passing the wire quickly and steadily through the flame of a paraffin lamp. The construction of these tubes is shown in fig. 1. The platinum wire ab is kept stretched by two spiral Fia. 1. springs of copper, being silver-soldered to two extremities of these springs. Two loops J at the other extremities of the spirals pass over two pieces of glass rod gg, gg, which are passed in by side tubes, blown on to the main glass tube; and the spirals pull on the glass rods. The ends of the side tubes are sealed up after the glass rods are in their places, with the exception of one, which is used for con- necting to the Sprengel pump, and is finally sealed when a complete 436 On Radiation from Dull and Bright Surfaces. [June 16, vacuum has been made. Flexible copper electrodes, ee, are silver- soldered to the loops at the ends of the copper springs, and to multiple platinum wires which are sealed into the glass tube at A and B. Fine platinum wires, pp, are attached to the main wire, and © are brought through the sides of the glass tube; and these serve as potential testing electrodes. The two tubes and their fittings are, as has been said, perfectly similar in every respect, except that one platinum wire is covered with an extremely thin coating of lamp- black. The two tubes were attached to a glass fork, and were simul- taneously exhausted ‘with the Sprengel pump down to about two millionths of an atmosphere, all the well-understood precautions as to drying, &c., being carefully attended to; and they were then at the same moment sealed off from the pump. The length of the tubes AB is 22 inches over all; and the internal diameter of the tubes Zinch. The distance between the potential electrodes pp is 15 inches (381 centimetres). The diameter of the platinum wire ah is 0-022 inch (0°0599 centimetre). On testing the resistance of the two platinums between the potential electrodes, cold and at the same temperature, 1t was found to be the same for both to less than one one-thousandth part of the resistance of either of them. The tubes having been prepared as described above, they were connected in parallel arc to a battery of six secondary cells in series, a variable platinoid wire being added in series with the tube con- taining the bright platinum, in order to regulate its current; and a rheostat designed for carrying strong currents was used to control the whole. The connexions will be readily understood from a glance at fig. 2. Fie. 2. bright pl alinum. ~~ () r\ : variable 2 WLre. Battery eee ||| || | Se ee With the rheostat and the variable platinoid wire the two plati- nums were then brought to the same incandescence (as judged by the eye) at various brightnesses from just visible redness up to nearly white heat; and the resistances of the platinums between the potential 1887.] On the Blood- Vessels of Mustelus Antarcticus. 437 electrodes were measured by means of a high resistance reflecting galvanometer, suitably arranged, with shunt and interposed resistance, for the purpose in hand. The result of my experiments is to bear out completely the deduc- tion which I had made from Mr. Mortimer Evans’ numbers; and to show that the temperature which produces, for example, the appear- ance of a certain red heat, is very much higher when the surface of the heated body is dulled than when it is bright as in a polished metal. J am not yet prepared to give a definite numerical com- parison ; but in order to show that the difference of temperatures referred to amounts to many degrees of temperature, 1 may be allowed to give the following statement. The two wires being at the same dull red heat, which from previous experience I estimate at perhaps 600° C., in the case of the bright- surfaced wire, the ratio of the resistance of the lamp-blacked platinum to the bright platinum was 130:93. Platinums differ very much as to variation of resistance with temperature; but in most specimens the resistance is doubled, when the temperature is raised from 0° C. to a temperature of from 300° C. to 400° C.; and for any particular platinum wire the change in resistance is almost in simple proportion to the change in temperature. From this statement it may be judged that the difference of temperatures between the two platinums, dull and bright, when giving out the same light, was a great many degrees centigrade. The difference of temperatures of the two glass envelopes was also very striking. The glass tube containing the bright wire was not even unpleasantly warm; while in the case of the other it was so hot as to blister the skin of the hand; and in this connection it is to be remembered that the vacuum in the two tubes was the same. I propose as soon as possible to continue this investigation and render it more complete. XXIV. “Note to a Paper on the Blood-vessels of Mustelus Antare- ticus (‘Phil. Trans.,” 1886).”. By T. JEFFERY PARKER, B.Sc. Lond., Professor of Biology in the University of Otago. Communicated by Professor M. FostEr, Sec. B.S. Received May 2, 1887. My attention has been called by a perusal of Professor Milnes Marshall and Mr. C. H. Hurst’s ‘ Practical Zoology’ (London, 1887), to an omission in my description of the venous system. These authors describe and figure, in Scylliwm canicula (pp. 218 and 224) a trans- verse anastomosis, the inter-orbital sinus, connecting the right and 438 Dr. J. C. Ewart. On Riger Mortis in Fish, [June 16, left orbital sinuses, and running in the floor of the skull immediately caudad of the pituitary fossa. I find that this anastomotic trunk is present in Mustelus antarcticus, in which species, however, it hardly deserves the name of sinus, being only 1 mm. in diameter in a dog-fish 1 metre long. Its median portion is situated, not in the actual cartilage of the skull-floor, but in the thick perichondrium of. the pituitary fossa, where it lies. immediately dorsad and caudad of the arterial commissures w (fig. 6, Plate 35) at their point of crossing. Passing laterad on either side it pierces the cartilage of the cranial floor, and finally enters the orbit by an aperture placed just cephalad of the trigeminal foramen, and about 5 mm. caudad of the carotid foramen. I doubt whether this can be the anastomotic trunk deseribed by Robin (see p. 712), since it is not situated ‘‘derriére les orbites,” and. can hardly be described as “‘ un sinus plus ou moins vaste.” The vessel in question ought to have been shown in the diagram, fig. B (p. 723) as a narrow trunk connecting the orbital sinuses (orbit. s.), and should have been referred to in the general account of venous. anastomoses on p. 722. XXV. “On Rigor Mortis in Fish, and its Relation to Putrefac- tion.” By J. C. Ewart, M.D., Regius Professor of Natural History, University of Edmburgh. Communicated by J. BURDON SANDERSON, F.R.S. Received June 6, 1887. 1. The Nature of Rigor Mortis. It has been long recognised] that rigor varies extremely not only in the time of its appearance, but also in its intensity. It may be well marked and resemble closely a spasm, or so indistinct that it is. better compared to a stiffening than to a contraction of the muscles. So much is this the case that it might be convenient to describe: rigor as accompanied with contraction in some cases and with stiffening in others. I have often noticed that when rigor comes on immediately after the loss of muscular irritability, it looks extremely like contraction; but when it is postponed for days, by lowering the: temperature or otherwise, it more closely resembles coagulation. IL am inclined to believe that whether the rigor resembles a contraction or a mere stiffening depends on the condition of the nervous system. If the coagulation of the myosin takes place at or about the same time as the death of the nerves, the rigor will to a certain extent. be physiological, and simulate a contraction in the extension of the fins, the bending of the trunk, &c.; whereas if the coagulation only sets in some hours, or it may be days, after the death of the 1887. | and its Relation to Putrefaction. 439 nerves, the rigor will be purely pathological, and consist of a mere fixing of the muscles in whatever position they happen to be. Another important consideration is what determines the time of appearance and strength of the rigor. In some instances I have been unable to detect rigor, in others, it has appeared at ordinary temperatures, a few minutes after death, while in other cases it appeared from ten to twenty hours after death. Again in some cases it is extremely weak and of short duration, whilst in others it is well marked and pro- longed. It may be safely asserted that if all the nerves in a given muscle were destroyed, that muscle would still pass into rigor. But although the rigor would probably set in were all the nervous ele- ments destroyed, the nervous system has apparently considerable influence in determining the time of appearance of rigor. Some physiologists seem to believe that the rigor comes on when and only when death has reached the muscles, by travelling in some cases hurriedly, in others slowly, from the central nervous system along the motor nerves. I hope to show that the longer the central nervous system continues to act, not only will the muscles sooner die, but the rigor will be the weaker and shorter, though in some cases from the arching of the trunk and extension of the fins, it- may appear to be otherwise. Let us suppose that two fish are instantaneously killed, the one in a vigorous, the other in an exhausted condition. In the former a. considerable time will elapse before the energy of the muscles is. exhausted, before the explosive material is all used up, while in the latter the muscles having already expended nearly all their energy during life, and little or no new productive material having been formed after death, they will soon die. Further, in the fish killed in an active condition, the muscles will give rise to a well-marked lasting’ rigor, whilst in the other it will be weak and of short duration. The result of artificial exhaustion is the same as that of natural. If a rabbit is killed and immediately after death the muscles of one hind limb exhausted by an interrupted current, rigor sets in in the ex- hausted limb two to three hours sooner than in the other. In the same way, if a fish is tetanised immediately after death, rigor sets in quicker than in another fish which has escaped stimulation. But. further, if two fish are killed and the central nervous system at once destroyed in one, but left intact in the other, rigor will be considerably later in appearing in the pithed fish. The explanation possibly may be that the central nervous system after death tends to exhaust the latent energy of the muscles by constantly stimulating them into action; while, on the other hand, when the central nervous system is. destroyed, the muscles are not stimulated into action, and there-- fore their final passage into rigor depends chiefly on the tempera-. ture and other surroundings. A440 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, 2. The Ordinary Phenomena of Rigor in Fish. The changes which take place before and during rigor will be best illustrated by the following experiments :— (1.) Physiological Laboratory, Oxford, 4th February, 1887, 3 p.w.—A large active perch (Perca fluviatilis) was taken from the tank and laid on the floor of the Laboratory, temperature 48° F. For about twenty minutes the perch at irregular intervals was very active, but the move- ments gradually diminished, and about thirty-five minutes after it left the water, all movements had ceased and there was no response to mechanical stimulation. When stimulated at 3.45 by induction shocks, there was no response until the secondary coil indicated 15 cm.* The muscular irritability gradually diminished, and at 5.45 there was only a slight response at the break with the secondary coil atOcm. At 5.50 the lower jaw and gill-covers were nearly rigid, and the irritability had quite gone in the muscles near the root of the tail, the last to survive. At 6.0 the pectoral and dorsal fins were rigid, and at 6.10 the rigor had extended as far as the pelvic fins. At 6.15 the whole fish had passed into a pronounced rigor, the mouth was open, the gill-covers projected outwards, all the fins were extended, and owing to the shortening of the muscles of the left side, the fish (which was 9 inches in length) was sufficiently curved to form ‘an are.of a circle 50 inches in diameter. ... While the.muscles remained irritable, they were neutral or amphichroic, but as the rigor extended. from before backwards they became distinctly acid. As soon as the rigor had set in the perch was placed under a bell- jar ina porcelain dish containing sufficient water to keep the skin moist. At 10 p.m. the rigor was still well marked, but next morning (5th February) at 10 a.m., the rigor had disappeared from the lower jaw, gill-covers, and pectoral fins. When placed with the convex side looking upwards, the lateral curvature of the trunk soon gave way and at 12 noon the whole fish, except about 5 inches at the tail end, was quite limp. At 10.30 a.m., the muscles in front of the dorsal fin were neutral, those behind distinctly acid, at 12 noon the muscles of the anterior half were slightly alkaline, those near the root of the tail were still neutral. Numerous bacteria were found in the layer of muscles lying around the body-cavity, and a few were found in the muscles under the skin in front of the dorsal fin, but no bacteria could be discovered either by direct observation or by cultivation in the muscles near the root of the tail. On the 6th February putrid odours were discernible, all the ‘* A single Daniell was used in the primary coil in the Oxford, and two Smees in ~ the Edinburgh experiments. 1887. | and its Relation to Putrefaction. 44] muscles were getting soft, and bacteria, plentiful in the muscles around the body-cavity, were extending into the caudal region. In this case death occurred about 35 minutes after the fish was taken from the water: muscular irritability disappeared and rigor began to appear 2 hours 15 minutes after death, the rigor was com- pleted in 25 minutes after it set in, and it had vanished about 21 hours after death. (2.) Zoological Laboratory, Edinburgh, 25th March, 10 a.m.—A common eel (Anguilla vulgaris) 18 inches in length, was killed by knocking on the head. At 6 p.m. (8 hours after death) the whole trunk responded freely to mechanical stimulation and the heart was still beating. At 10 a.m. of the 26th (24 hours after death) there was only a feeble response to mechanical stimulation, but strong con- tractions were produced when the electrodes from an induction coil were applied to the skin,—the secondary coil at 15 cm. Atl p.m. the muscular irritability had slightly diminished in the anterior third, at 6 p.m. it was still less marked, and at 10 a.m. of the 27th (48 hours after death), with the secondary coil at zero, the muscles of the anterior third contracted very slightly. At 12 noon the muscles of the anterior 5 inches gave no response, but those of the middle third still con- tracted readily, and the muscular irritability increased towards the tail end. Two hours afterwards (7.e., 52 hours after death) the greater portion of the anterior third had become rigid—the rigor beginning in the lower jaw and passing backwards affecting the gill- covers and pectoral fins and then the muscles of the trunk. At 4p.m. the muscles of the anterior portion of the middle third of the eel no longer responded to electrical stimulation, and at 8 p.m., the anterior half (about 9 inches in length) was rigid while the posterior half still responded when stimulated—the strength of the contractions still increasing from before backwards. The muscles of the rigid half had a distinctly acid reaction, those of the posterior half were neutral or very faintly alkaline—a narrow zone near the centre being amphi- croic. The muscles of the anterior third immediately under the skin were neutral and contained no bacteria, but those next the peritoneum had a few bacilli and micrococci, and were alkaline in reaction. On the morning of the 28th (9 a.m.) the rigor had all but dis- appeared from the anterior third, the middle third was quite stiff, and the posterior third, except near the tail end, contracted very feebly with the secondary coil at zero. ' At 1 p.m. rigor had passed from the anterior half, but the muscles of the posterior third were still irritable. The reaction of the muscles in the anterior third was now slightly alkaline, and they contained a few bacilli and micrococci similar to those found on the previous day in the muscles around the body-cavity. At 5 p.m. only the terminal 3 inches responded when the electrodes were introduced 442 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, into the muscles, and the rigor was passing from the remainder of the middle third and making its appearance in the front portion of the posterior third. At 6 p.m. the rigor had all but gone from the middle third, and a weak rigor had set in in the posterior third. At 8 p.m. (82 hours after death) the whole eel was quite limp—the rigor on the posterior third having been weak and of short duration. The alkaline reaction increased from before backwards, to about 3 inches from the tip of the tail, where it was neutral, and bacteria could be detected in the muscles a little beyond the middle half. Next morning (29th March) all the muscles were alkaline, and a few bacteria were present even in the muscles near the tail end, and the anterior portion was smelling slightly. This eel was under observation until the 13th April, when putrefaction had considerably advanced. While under observation the eel was kept in water which varied from 48—52° F. I may add that the blood and peritoneal fluid were examined immediately after death, and that though small bacilli were fairly abundant in the lymph, it was impossible to dis- cover any organisms in the blood. In this eel the muscular irritability lasted in some of the muscles for nearly eighty-two hours after death. As a contrast to this above experiment, I may describe shortly another. (3.) On the 6th April, an eel, also about 18 inches in length, which was killed by an electrical shock from a Holtz machine, passed imme- diately into rigor—what might be called “cataleptic rigor.” The posterior half—in which there is no body-cavity—was sterilised (by placing it for a short time in a 5 per cent. solution of phenol) and then introduced with the usual antiseptic precautions into a jar of sterilised distilled water. The rigor still (June 16th) continues on this portion (the posterior half) of the eel, while the anterior half, which was introduced into a 5 per cent. solution of phenol after the rigor had disappeared, is now quite limp and soft. From these experiments it may be inferred that under ordinary conditions there is an intimate relation between loss of irritability and the setting in of rigor, and that rigor vanishes as the bacteria invade the tissues. 3. The Time at which Rigor appears. Under ordinary circumstances the setting in of rigor in the various kinds of fish seems to depend on the amount of irritability of the muscles at death. in all probability it might be possible to dis- cover when the rigor would come on by determining the amount of free acid in the muscles; in other words, there is a relation between the appearance of the rigor and the amount of catabolic material in the muscles at death. This seems to vary in an unac- countable way; e.g., if three two-year-old trout of as nearly as 1887. ] _ and its Relation to Putrefaction. 443 possible the same size, which have been living under as nearly as possible identical conditions since the day of hatching, are captured at the same moment while lying quietly in the corner of a tank, and allowed to die in the landing net, the rigor may appear in one (A) 15 minutes after death, in another (B) 30 minutes, and in the third (C) 40 minutes after death. We must suppose that this variation results either from the condition of the muscles at death, or from the influence of the nervous system. If at death the muscles of (C) contained (owing to the oxygenation of the blood continuing longer) less bye-products than (A), it might be possible to understand why the time at which the rigor set in differed. Again, if in (A) the nervous system continued to produce muscular contractions longer than in (C), z.e., led to the more com- plete exhaustion of the muscles of (A) than (C), the difference might . be easily understood. It is of course difficult, if not impossible, to determine which (if either) of these explanations is the correct one, but that they may both have some influence in the result may be in- ferred from the following facts. (1.) If two trout are taken from the water at the same time, and one is left with its gills freely open in the landing net, while in the other the gills are kept firmly closed by an elastic band, the one with the gill-covers extended will die, it may be 20 minutes before the other,* but will be 30 to 40 minutes later in becoming rigid, the reason apparently being that the closed gill-covers prevent the evaporation from the gill-chamber, and the consequent increase in temperature and loss of function of the gill-filaments. (2.) If two trout are taken from the water at the same time, the one allowed to die in the landing net, while the other is at once killed and pithed, the rigor sets in in the former several hours (4—8) sooner than in the latter, z.e., it is later in appearing in the fish in which the brain has been destroyed. Although in some cases it is difficult to account for the time at which the rigor sets in, fairly satisfactory explanations can be given in others. It is well known that most fish can live for months with- out food. In fact fish in confinement often appear to “thrive” best when not fed, they are less sensitive and less liable to suffer from disease. Hven in a wild state fish seem to all but give up feeding for weeks at a time, more especially during the spawning season, and the chief difference between under-fed and well-fed fish appears to be that in the former there is little or no growth, and the spawning period is delayed or the formation and maturation of the roe and milt are arrested. But although many fish are capable of living for months without food in aquaria, now and then one sickens and dies without any apparent cause. * This was first pointed out to me by Sir James Maitland, Bart., when visiting the Howieton Fishery. 444 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, As in warm-blooded animals which die before maturity is reached from wasting diseases, the rigor soon appears and as rapidly goes, so in young fish which have been living in confinement, the rigor is often weak and evanescent. | For example, a young roach about 6 inches in length, which for some hours had barely managed to survive was killed, and, though carefully watched, it was impossible to detect any rigor, and equally impossible fifteen minutes after death to obtain any response from electric stimulation with the secondary coil at zero. Again, asin a “hunted hare” the rigor sets in rapidly and is of short duration, so it is ina long “ played” fish. On April 14th a trout was chased for nearly half an hour before it was landed. About 20 minutes after it was taken from the water, even although the brain was destroyed immediately after death, the muscular irritability had disappeared, and the rigor was complete before 30 minutes had elapsed with the temperature at 9°5° C. Under ordinary conditions, if an active two- year-old trout (S. levenensis) about 9 inches in length is taken from the water and left in the landing net, it usually lies perfectly still, only giving an occasional wriggle. During the first few minutes the breathing movements are performed, but as soon as the fish realises fully it is out of the water, the mouth and gill-covers are tightly closed—an instinct which fish display, whereby they better their chance of surviving until they again perchance reach their native element. In from 20 to 30 minutes, probably owing to the muscles being ex- hausted, the mouth is opened and the gill-covers are widely extended, and in a few minutes later (5—10) the fish dies. If it dies in about 25 minutes, the- muscles will respond to mechanical stimulation 10 minutes after death, and 60 minutes after death all the muscles will respond freely to electrical stimulation with the secondary coil at 15cm. Gradually the muscles from before backwards lose their irritability, and 15 hours after death, though the muscles near the tail still respond with the secondary coil at 15 cm., the muscles of the lower jaw will only respond when the indicator is at zero, and 2 hours after death only the muscles of the posterior half of the trunk retain their irritability. At 25 hours after death even the caudal muscles require the secondary coil at 12 cm.; 10 minutes later at 8 cm., and in 15 to 20 minutes more (about 3 hours after death) only a faint response is obtained with the secondary coil at zero. Two hours after death—before muscular irritability has gone from the caudal muscles—the muscles of the jaw become rigid and the stiffen- ing extends backwards, overtaking the gill-covers, the pectoral, dorsal, and pelvic fins and one myotome after, until the rigor is complete. . The time required is never the same, but on an average the rigor is accomplished in a trout allowed to die in a landing net, and 1887. | and its Relation to Putrefaction. 445, kept afterwards in the air at a temperature of 9° C., in from 1 to 13 hours—3 to 33 hours after death. When a trout is taken from the landing net immediately after all signs of life have gone, and placed in water at the same temperature (9°C.) the irritability continues about 10 minutes longer, and the rigor is from 15 to 20 minutes later in setting in. When the temperature is raised to 15° C. the irrita- bility goes, and the rigor appears in from 20 to 50 minutes, and reaches the caudal muscles about 45 minutes after death. Ata tem- perature of 25° C. therigor may set in in 15 minutes, and be complete in about 25 minutes after death, while at a temperature of 30° rigor often comes on in the trout 5 minutes after death, and vanishes 15 or 20 minutes later. Ata temperature of 38° C. heat rigor at once sets in. As the temperature is lowered the rigor is later in making its appearance, and a considerable period elapses between the loss of mus- eular irritability and the setting in of rigidity. At low temperatures it is often extremely difficult to say at what time the stiffening begins. A trout in water at 1° C. seemed to pass into rigor about 23 hours after death; at —1° C. there was no distinct rigor 30 hours after death, but well-marked stiffness 10 hours later, but at lower temperatures (—7° to —20° C.) neither rigor nor stiffening could be detected in four trout which had been respectively 2, 3, 4, and 5 days in the freezing mixture. Further, trout which had been subjected to a tem- perature below —7° C. never stiffened, even when introduced imme- diately after thawing into water at a temperature of 25° C. Judging from the above and other experiments, it seems that raising the temperature either before or after death has the same influence as muscular or nervous exhaustion in hastening the rigor. The increased temperature quickens all the chemical and other changes, and thus leads to the rapid and all but complete destruction of the catabolic material stored up in the muscles. On the other hand, cold either diminishes or arrests the metabolic changes. Ata temperature below freezing point the muscles contract, even when stimulated less quickly, and hence they long retain almost unaltered the contraction- producing material which happens to be present when death sets in; so that when the rigor eventually appears it, as already mentioned, more resembles a mechanical coagulation of the muscles than a strong contraction. It is difficult to determine whether the rigor, which appears at a low temperature (5°, to —1°C.), is really stronger than the rigor that comes on at a high temperature. When a trout, in which the rigor has set in at a temperature of 2° C., is placed in water at a temperature of 25° C., stiffening vanishes in about the same time as it would had the rigor set in at a temperature of 20°C. The intensity and duration of the rigor which follows death in warm-blooded animals from lightning has been again and again AAG Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, discussed. It is stated by some that rigor never appears, whilst others assert that the rigor which follows death by lightning is often well marked and of considerable duration. From experiments made with fish it seems that in some cases the rigor may be instantaneous and well marked, or it may appear some time after death and be of short duration, whilst in others it may resemble closely the rigor that sets in after death from ordinary causes. When a trout receives a sufficiently strong electric shock it is instantaneously killed, and at the same moment thrown into a well-marked tetanic spasm which passes directly and almost imperceptibly into rigor. A trout about 10 inches in length which received a strong shock* by placing one electrode under the left gill-cover and the other (a chain) round the tail, was thrown into a pronounced spasm which closely resembled a heat rigor ; the lower jaw was depressed, the gill-covers widely opened, the fins fully extended, and the trunk strongly arched. After the shock the gill-covers and tail quivered two or three times, and in about five minutes the muscles lost their irritability, and in three minutes more were strongly acid. Ten minutes after the shock the fins became if possible more extended than before; this further extension indicating probably the passage of the tetanic spasm into a true rigor. In all the experiments when a sufficiently strong current was used the result was the same, but on several occasions, though the current — was strong enough to cause death, the muscles recovered from the tetanic spasm, and rigor set in about one hour and twenty minutes after- wards. On other occasions, though the fish was thrown into a strong spasm and seemed dead, there was in from ten to fifteen minutes com- plete recovery. When fish, which had not only been killed by the shock, but had apparently also passed into a strong rigor, received several additional shocks not later than thirty minutes after the first, the rigor disappeared, and although the muscles failed to recover their irritability, rigor did not again set in for nearly an hour. This seems to confirm what has already been observed by others, that rigor up to a certain limit may be broken down and kept at bay for some time. The breaking down of the rigor may be accounted for by supposing that only a certain proportion of the fibres had stiffened, or that coagulation had been incomplete. It was especially noticed that when the muscles recovered from the first tetanic spasm in fish which had been killed, it was impossible to bring on a second spasm suffi- ciently strong to pass directly into rigor, and further that the spasm which appeared in fish stimulated after death was never so well marked as in fish which were simply under the influence of ether. * A Holtz machine was used, and the jar was 8% inches in diameter with coatings 18 inches high. Se le 1887. | and tts Relation to Putrefaction. 447 Nevertheless, when both the brain and spinal cord had been de- stroyed, the spasm was sufficiently strong to pass directly into rigor, showing that however much the peripheral nerves were concerned, “cataleptic rigor ”” was possible without the central nervous system. It has always been extremely difficult to account for partial cata- leptic rigors, such as sometimes occur in the battlefield from gunshot wounds. It has been supposed by Falk and others that these obscure rigors result from injury of the spinal cord. I had no difficulty in producing partial rigors in fish, e.g., when one electrode was intro- duced into the brain of a fish, and another into the muscles half along the lateral line, the anterior half of the fish was thrown into strong rigor, from which there was no recovery, while the rest of the fish remained quite limp for five hours after death. Before the posterior half of the fish had become stiff, the rigor had all but disappeared from the anterior half; the posterior half remaining rigid for nearly twelve hours. In the same way, in a fish in which the brain and spinal cord had been destroyed, the posterior half could be thrown into rigor which almost vanished before the anterior half became rigid. Hence we may suppose that in partial rigor a strong tetanic spasm has been produced directly influencing the muscles, or by injury of the nerves or the nerve-centres by which a particular group of muscles is controlled. I may mention that in several instances the electric current was seen to flash along the surface of the skin, and that when this happened there was often marked pigmentation of the one side, while the other remained pale, and further the muscles under the darkened skin were often quite rigid, while those under the unaltered skin remained for a time elastic and extensible. The influence of Faradaic currents and of often repeated continuous currents was very marked. A trout, e.g., in which after death first the brain and afterwards the spinal cord were stimulated, was thrown into spasms which became weaker and weaker until, 10 minutes after death, no response was obtained. In this case the rigor set in 20 minutes after death, and 20 minutes later it had extended to the caudal muscles. The appearance and nature of the rigor were always directly related to the previous exhaustion produced in the muscles. The effect of animal electricity seems to correspond to that of ordinary electricity, except that in fish killed by electricity from electric organs thé rigor seems later in setting in. For example, in two small roach killed by the electric eel (Gymnotus electricus) in the insect house of the Zoological Gardens, London, on the 21st March, and kept under observation in water at a temperature of 45° F., no distinct rigor had set in twelve hours afterwards.* Two roach killed on March 31st about 5 p.M., after receiving numerous weak shocks * T am indebted to Mr. Romanes for making this observation. VOL. XLII. 2K | 448 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, — from the apparently exhausted electric organs, began to stiffen 10 hours afterwards, and were quite rigid 114 hours afterwards, the temperature varying from 50—44°F. On the 3rd April two other roach were “struck”? when the fish was vigorous, one was killed by the first shock, the other after receiving two shocks, and both were quite rigid 55 hours afterwards. We thus see that the setting in of the rigor is related to the strength of the shock received, but that even when the shock is strong enough to cause instantaneous death the rigor is delayed for several hours. The advantages of being able to kill the fish instantaneously without producing immediate rigor is evident enough. It would be often uncomfortable if not impossible for Gymnotus (and still more for the small-mouthed torpedo) to swallow a fish in strong rigor, and yet unless the fish were sufficiently ““numbed ”’ they would readily escape from their sluggish destroyers. — It may be mentioned that a trout which had been pithed immediately after death and placed in artificial gastric juice at a temperature of 100° F., became rigid in less than a minute, and the rigor com- pletely disappeared 35 minutes later. A similar fish in water at the same temperature became at once rigid, but the rigidity persisted for an hour and ten minutes. . Experiments were made to determine the influence of acid, alkaline, and other solutions in bringing on and keeping back rigor. Salt solution, as is well known, prevents rigor setting in in proportion to its coming into contact with the muscles. Alkaline and septic solu- tions seem to have no influence either way, while acid and corrosive solutions seem to hasten its appearance, but the latter only to a limited extent. Generally speaking, whatever tended to influence the rigor influenced the irritability of the muscles, but at low temperatures there was no relation between the disappearance of the irritability and the setting in of the rigor. The muscles lost beyond recovery their irritability in the trout when the temperature was kept for a few minutes at —70° C., but while this temperature was maintained no rigor appeared, and, as mentioned above, fish which were kept under —70° C. for severa] days never became rigid when removed from the freezing mixture; in some cases, however, they seemed to become slightly firmer—the continued freezing probably so alters the tissues that the usual coagulation or stiffening is rendered impossible. 4. The Duration of Rigor. There is, as generally believed under ordinary circumstances, a close relation between the duration of a rigor and the time at which it sets in; 2.e., if a rigor sets in half an hour after death, it is not likely to Jast long, while if it appears twelve hours after death, there is a probability that it will continue for several hours. On the other hand, - 1887. | ! and tts Relation to Putrefaction. - 449 there does not seem to be usually an intimate relation between the apparent intensity and the duration, for a short-lived rigor produced at a high temperature may look most pronounced, while a fish in a strong rigor (which may last for twenty-four hours or more) has often neither the gill-covers nor fins extended, nor the body dis- tinctly arched. We must suppose that there is some relation between the duration of the rigor and the condition of the muscles when it setsin. If before the rigor appears the latent energy of the muscles has been all but exhausted, either before or after death, naturally or artificially, the rigor though well marked will be of short duration, while on the other hand if a considerable amount of rigor-producing material is left when the stiffening supervenes, the rigor, though not strikingly resembling a tetanic spasm, will be more intense and more persistent. As the rigor comes on, all the muscles shorten (or contract), the extensors usually overcoming the flexors and the muscles of one side (or probably the red muscles of one side) overcoming the muscles of the other, and thus leading to arching or lateral curvature of the trunk. This curving is sometimes so intense that a fish 10 inches in length may form the arc of a circle little over 6 inches in diameter. Up to a certain time after the rigor sets in it may, either by electrical stimulation or mechanically, be broken down, not once, but several times; but the oftener the coming on of the rigor is interfered with, the final rigor is the weaker and the less persistent. Apparently at ordinary temperatures there is a regular order, not only in the stiffen- ing of the various groups of muscles, but also of: the various bundles of the individual muscles. If this is the case, the alternate appear- ance and disappearance of the rigor may, as already indicated, be accounted for by saying that when a partial rigor is broken down, the stiffening of certain muscles or portions of muscles has been arrested or destroyed, and when the rigor sets in again new muscles or muscular bundles have stiffened, while those in which the rigor had previously appeared either remain limp or have their rigidity completed. When rigor which has been fully established in isolated muscles or groups of muscles is destroyed, it never reappears. I have not yet succeeded in recording in a satisfactory manner the strength of the rigor under different conditions, but from the results already obtained, it appears the more rapidly the rigor comes on the more closely it resembles an ordinary muscle contraction. A comparative table showing the changes which take place in the muscles of different animals at different temperatures while the rigor is coming on and going off would be very instructive. It may be mentioned that in fish, as in other vertebrates, as the rigor comes on there is a rise in temperature, and the reaction changes often rapidly from slightly alkaline or neutral to distinctly acid. In a 2K 2 450 ~— Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, trout about 10 inches in length the temperature during life was 10°15°C., the temperature of the water being 9° C., and the air 9°3° C. After death the temperature fell to 9°5°, but as soon as the rigor had set in, the temperature of the muscles rose rapidly, reaching when the rigor was all but completed 10°3° C. Ten minutes after the rigor had been completed the temperature was 10°2°, and it gradually fell until it reached 9° C., fofty-five minutes after the maximum had been reached. In this fish rigor began to disappear two hours after death, and as the rigidity vanished the temperature again rose, being 10° C. three hours after death, 10°05° when the rigor, four hours after death, had vanished from the anterior third of the fish, and 10:03° when only the muscles of the tail continued rigid, when the fish became quite limp; six hours after death the temperature was again 9° C. As: putrefaction proceeded the temperature again rose to 10° C., and it varied between 9°5° C. and 10° C. for two days, after which it was the same as the temperature of the laboratory. The acidity increased: as the rigor came on, and then gradually diminished until the muscles: were neutral. As putrefaction advanced the tissues became decidedly alkaline. The rigor is least persistent in fish which die in an exhausted con- dition at a high temperature. If an exhausted trout is placed immediately after death in water at a temperature of 35° C., rigor appears in from 3 to 10 minutes and disappears in from 15 to 30: minutes, 7.e., at the most 40 minutes after death. If a trout is killed and pithed and then introduced into water at a temperature of 35° C., the rigor appears in from 10 to 15 minutes,. and persists from 50 minutes to 1 hour. In a fish treated in the same way at a temperature of 25° C., rigor appears in from 60 to 65 minutes, and persists for 24 to 3 hours; while a similar trout placed in water at 15° C. does not begin to stiffen for 5 hours, and the rigor may only be completed 7 hours after death, and begin to pass off about 20 hours after death. The nervous system has doubtless considerable influence in determining the length of the rigor, as it has in deciding its time of setting in. If an active trout (A) is carefully captured and allowed to die in the landing-net, which when undisturbed it usually does without a struggle ; and if when all signs of life in (A.) have vanished, a second trout (B) is secured and at once killed and the brain and spinal cord destroyed; in (A) the rigor may begin to disappear 2 hours after it has been completed, and may only last altogether 7 or 8 hours, while in (B) it may last at least 24 hours. When the brain only is destroyed it disappears from 1 to 1} hours sooner, the temperature: being from 9—10° C. The difference of the duration of the rigor in fish which are allowed to die and in fish which are knocked on the head or have both brain and spinal cord destroyed is well marked at all temperatures above’ Boot. | and its Relation to Putrefaction. 451 5° C., but at temperatures below 5° C. the difference is less evident, the cold serving either to paralyse the nervous system or to prevent the muscles responding to the weak stimulations which reach them. If two fish, one (A) with brain and cord destroyed, the other (B) with both intact (B having been allowed to die slowly in the net), are placed in water at a temperature of 25° C., the rigor in (A) persists for 24 to 3 hours, while in (B) it vanishes in 1} to 2 hours. If two ‘similar fish are kept under observation at a temperature of 5° C., in the pithed specimen the rigor may last three days, while in the other it may not last 48 hours. As it is impossible to suppose any vital changes take place after the rigor appears, its duration must depend on the condition the muscles are in when they become rigid, so that we must account for rigor in pithed fish persisting longer than in fish allowed to die naturally, in the same way as we account for rigor setting in at different times in fish differently treated. There is little to add to what has been already said as to the influence of temperature in driving off or maintaining rigor. In unpithed fish the rigor at a temperature of 35° C. may only last 30 minutes, at 25° C. it may last 5 hours; at 15° C. it may persist for 24 hours; at 10° C. 36 hours; at 5° C. 46 hours; at 1° C. three days. At —2° C. it continues unchanged for an indefinite time. On the other hand, in fish which after the rigor had set in were kept for Several days at a temperature between —7° C. and —20° C., the rigor disappeared before the thawing was completed. Perhaps the rigor was destroyed by alterations produced in the muscular fibres during freezing. It was certainly not owing to the direct contact of the salt and ice freezing mixture, for the same results were obtained when fish were frozen in air, and in fresh water an stoppered bottles. That the rigor persists until the fish are thawed ‘does not seem probable, because it persists for some time after thawing in fish which have been for ten days at —2°C., and true rigor never appears in fish which have been kept for several days below —7° C. The duration of rigor which occurs after death from an electric shock varies considerably, the variation evidently depending either von the direct influence the charge has had on the muscles or on the condition of the central nervous system after the shock. In a trout which was killed and thrown into instantaneous cataleptic rigor at one and the same moment, the rigor began to disappear from the jaw and gill-covers 74 hours afterwards, and 16 hours later it had completely passed off. In another trout in which only the anterior half was stimulated, the rigor had passed off 9 hours afterwards, about 3 hours after the rigor appeared in the pos- terior unstimulated portion. Conversely when the shock was passed through the posterior half of a trout, the rigor continued antil 83 hours after death, while the rigor in the anterior half, 452 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, which was completed 6 hours after death, lasted 11 hours, the order of appearance and disappearance in this case being —— reversed. In a trout, in which one electrode was in contact with the in while the other was in the water, the fish was thrown into a strong spasm, but not instantaneously killed. The skin of both sides behind the point of contact of the electrode (which was near the head) became deeply pigmented, the jaws and gill-covers continued to: move at intervals for 30 minutes, after which there were no signs of life. The tetanic spasm seemed to pass off to a certain extent, but as soon as the gill-covers stopped acting, the muscular irritability was lost, and a strong rigor set in which lasted for nearly 15 hours. Another trout, which was tetanised and killed by an electric shock, recovered from the spasm and passed into a rigor 24 howe after-- wards, which only lasted 7 hours. Another trout, which was killed, but not permanently tetanised by the first shock, received seven other shocks, some of them of great intensity. In less than an hour after the frist shock rigor set in, but it was of short duration, for in 20 minutes after the stiffening appeared the jaw and gill-covers were relaxed, and the whole fish was. soft and limp 14 hours after death. It may be files for granted, from the experiments made, that the prolonged rigor of pithed fish is closely related with the destruction of the central nervous system, but it does not necessarily follow that the strength of the rigor in fish, instantaneously killed and stiffened by an electric shock, has the same explanation. It is doubtless. possible that a single strong shock may, by destroying the nervous: apparatus, produce the same results as pithing, but it is also possible that the appearance and duration of the rigor in fish killed by electricity may be largely eto neee by SPecce changes in the muscles. The observations made as to the appearance and duration of rigor in the trout have been confirmed by control experiments on other fish. It will be sufficient in the meantime, to refer to the behaviour of the perch (Perca fluviatilis), roach (Leuciscus rutilus), and eel (Anguilla vulgaris), under conditions similar to some of those above mentioned. In a roach, which died in an exhausted condition, there was no response to mechanical stimulation, and 30 minutes after death only a weak response at break, with the secondary coil at 0'0 cm. It was. almost impossible to say either when the rigor set in or disappeared, and four hours after death the muscles of the trunk were alkaline, and contained bacteria. A similar roach, which was killed by a blow on the head and afterwards pithed, responded freely to mechanical stimulation for 1 hour and 20 minutes. At first the movements were 1887.] and its Relation to Putrefaction. 453 vigorous, e.g., when held in the vertical position half an hour after death, all the swimming movements were repeated. At 1 hour and 40 minutes after death the muscles responded with the secondary coil at 15 cm., and they still responded 9 hours afterwards with the secondary coil at 0'0 cm. Soon after the irritability of the muscles was lost, rigor set in, and extended slowly backwards without produc- ing very marked extension of the fins, and was completed about 19 hours after death. The rigor persisted unaltered for 11 hours, when it slowly vanished in the same order as it appeared, leaving the anterior two-thirds of the fish quite flexible about 36 hours after death, but remaining in the posterior third for nearly 7 hours longer. The temperature in both cases varied from 11° C. to 12° C. When a somewhat exhausted roach was placed in water at a temperature of 35° C., the muscles rapidly lost their irritability and the rigor set in 30 minutes after death, was well established in 45 minutes, and was disappearing 2 hours after death, and quite off 2 hours 45 minutes after death. At a temperature of 20° C. the rigor set in 1 hour and 30 minutes after death, and had all but passed off 4 hours after death. At a temperature of —1° C. the rigor came on extremely slowly. On placing several roach in water at a temperature of —1° C. and taking them out at intervals, I came to the conclusion that in small roach the rigor set in between 24 and 27 hours after death. In roach which had been in water at a temperature of —1° C. for 9 days, the rigor persisted for several hours after thawing, even when this was done very slowly. In the perch, generally speaking, the irritability of the muscles lasts longer the later the rigor is in appearing; e.g.,in a perch about 11 inches in length, which had been killed and pithed, the muscles were slightly irritable 13 hours after death, and the rigor was only fully established 9 hours later, and it had only disappeared from the anterior two-thirds of the fish 48 hours after death. But even a vigorous perch, if allowed to die in the usual way, may lose its muscular irritability and pass into rigor 23 hours after death, and become flexible again 16—18 hours after death, at a temperature of 11°5° C. 5. The Disappearance of Rigor. It has long been admitted that there is some relation between the disappearance of rigor and the beginning of putrefaction, that in fact putrefaction assists in driving away the rigor. While endeavouring to discover a simple means for preserving fish in a fresh condition last autumn, it occurred to me that there might be a closer relation between rigor and putrefaction than had hitherto been determined, and that it might in fact be possible to prevent putrefaction by main- taining the post-mortem rigidity of the muscles In order to ascer- 454 Dr. J. C. Ewart. On Rigor Mortis in Fish, [June 16, tain what ground there was for entertaining this notion, I proceeded to study the origin and nature of rigor in fish and other animals. At a very early stage I learned that the longer the rigor lasted the longer putrefaction was delayed, and also that putrefaction set in quicker in fish in which there was a large amount of putrescible matter in the alimentary canal, than in fish in which the alimentary canal was practically empty. For studying the relation of bacteria to the disappearance of rigor, I at the outset used sea fish, but afterwards trusted chiefly to fresh water forms, owing to the great difficulty in obtaining haddock and other fish in a perfectly vigorous condition. IT soon observed that haddocks and whiting which were knocked on the head when captured (after the manner long practised by the fishermen who send “live” cod to Billingsgate) were longer in stiffening than fish which were left wriggling as long as their energy lasted in the hold of the boat. Later I found that the rigor per- sisted longer in haddocks and whiting which were gutted immediately after capture than in ungutted fish. If, e.g., we take six haddocks (about the same size and captured on the same fishing bank at or about the same time) and, (1) leave two (Series A) to die in the usual way (temperature 7—8° C., (2) kill two (Series B) by knocking on the head and then pith, and (8) kill the other two (Series C) and both pith and gut; in Series A the rigor may appear 10 minutes after death, but in B and C it may not set in for 2 or3 hours. Further, in A the rigor may have disappeared from the trunk (the portion co-extensive with the body-cavity) 10 hours after death, while in Bit may persist for 13 hours, and in C for 20 hours, and while A might be quite limp 21 hours after death, B might continue rigid for 25 hours and C for 30 hours after death. | It may be taken for granted that rigor results chiefly from the formation and coagulation of myosin, and further, that the intensity of rigor depends on the amount of myosin formed in the various muscles. If nearly all the myosin-forming material has been used up before rigor appears in producing muscular contractions, compara- tively little myosin will be formed, while in fish which have been pithed (if pithing diminishes the muscular contractions) there will be (except when the rigor is greatly delayed, as in the tail of the eel) sufficient material left to admit of a considerable amount of myosin appearing in the substance of the muscles. But after all the amount of myosin formed in any given muscle accounts rather for the firmness of the muscle during the rigor than for the duration of the rigidity. Why does the myosin not continue unchanged ? Why does it not, as it were, liquefy ? And why does the rigor persist not only longer in some fish than in others, but also longer in some parts of individual fish than in others ? 1887. ] and its Relation to Putrefaction. 455 Experiments show that the rigidity is easily overcome (1) by alternate flexion and extension; (2) by raising the temperature ; (3) by freezing; (4) by the action of acids and alkalies; and (5) by means of organisms. That this last cause is more important than ail the others put together might, perhaps, be inferred from the fact that in fish in which bacteria abound in the tissues at death, either no rigor or a very weak one makes its appearance. This inference is confirmed by the following observations and experi- ments. (1.) A septic solution was injected into the right femoral artery of a newly killed rabbit, the rigor, though it appeared about the same time in the right limb as iu the left, disappeared much quicker from the right. (2.) A large roach was killed on the 4th February and at once gutted. The muscles of the right side, imme- diately in contact with the peritoneal lining, were inoculated by septic bacteria (introduced by pricking the peritoneum with a rosette of needies fixed in a piece of sealing-wax) and the peritoneum covering the left side of the body-cavity was washed with a solution of corrosive sublimate (1 in 10,000). The rigor was to my surprise equally well marked on the two sides; but 24 hours after death, when the rigor began to disappear, the right side became limp about 25 hours before the left, and 36 hours after death the muscles of the right side were soft and beginning to putrefy, while those of the left were still firm; further, a piece of muscle taken from under the skin of the right side opposite the anterior margin of the dorsal fin swarmed with bacteria, while a piece of muscle from a corresponding point on the left side contained comparatively few bacteria. (3.f Roach and trout, which were gutted immediately after death, and dipped for a time in solutions of phenol (5 per cent.) and corrosive sublimate (1 in 1,000), and afterwards introduced into sterilised water, retained their rigor unimpaired for an indefinite time. Whenever the fish, however, were transferred from the sterilised into ordinary water, rigor began to disappear—the passing off being always accelerated when organisms were introduced into the water, or when the tempera- ture was raised. Believing the rigor in the above fish might be mere stiffening produced and maintained by the action of the phenol and corrosive sublimate solutions, I introduced fish from which the rigor had been driven off by heat into similar solutions of phenol and corrosive sublimate. Limp fish treated in this way never became stiff—the natural firmness of the fresh muscles was simply maintained. (4.) Eels which were thrown into instantaneous rigor by strong electric shocks behaved in the same way. The posterior half of a large eel (the part behind the body-cavity) in cataleptic rigor was placed in phenol and then in sterilised water on the 8th April. A similar portion was introduced on the same day into sterilised water after the skin had been rendered aseptic by corrosive sublimate. 456 Dr. J.C. Ewart. On Rigor Mortis in Fish, [June 16, Both specimens are still (June 16th) in well marked rigor, and in the muscles near the cut surface have been unable to detect any bacteria, and the reaction of the muscles is still slightly acid. ; These and other experiments justify the conclusion that rigor, under ordinary circumstances, is in all probability driven away by putrefactive organisms. One of the most remarkable changes which accompanies the disappearance of rigor is the change of reaction of the muscles from acid to alkaline. As soon as the rigor begins to lose its hold the acidity diminishes, and gradually or rapidly dis- appears; for a time the muscles are neutral, but sooner or later they are distinctly alkaline. The muscles around the body-cavity become alkaline first, from these muscles the alkalinity extends outwards towards the skin, and later extends into the muscles\of the tail, but in some cases a long interval elapses between the appearance of the alkaline reaction in the sub-peritoneal muscles and the myotomes _ situated behind the body-cavity. A point of considerable interest is that the reaction of the muscles under the skin passes from acid to alkaline before they are invaded by bacteria. This can be readily proved by introducing into a culture-medium a fragment of muscle from under the skin of the trunk from which the rigor has just gone, and which is already faintly alkaline, and as a test experiment a similar fragment from under the peritoneum from a point as nearly as possible opposite where the first was taken. In the latter case bacteria rapidly appear, while no bacteria (if all the necessary condi- tions have been observed) will appear in the former. By a series of experiments I have proved that while weak solutions of hydrochloric - and sulphuric acids are incapable of preventing the putrefaction of fish, they have the power of arresting or at least greatly retarding the development of ordinary bacteria. Seeing that the alkaline wave radiates from around the body-cavity in advance of the bacteria, it is extremely likely that the one results from the presence of the other.. In fact we may, until further experiments have been made, suppose that rigor disappears in the presence of a. species of fermentation, that the bacteria which reach the tissues from the body-cavity manu- facture ferment-like substances, which as they diffuse through the muscles drive the rigor before them, adapting the tissues on the way for the suitable reception and nourishment of a crop of putre- factive bacteria in much the same way as the husbandman breaks up and otherwise prepares the soil before sowing his corn. In all pro- bability the duration of the rigor partly depends on the readiness with which the tissues can be made alkaline, and partly on the amount of mechanical obstruction the bacteria have to overcome in the muscular fibres. It is well known that gelatine and other culture-media, when slightly acid, or when too much dried, are rendered for a time altogether unsuitable for the cuitivation of £387.| - and its Relation to Putrefaction. 457 certain bacteria. In the same way the muscles of certain fish, either because of their peculiar chemical composition, or because of the peculiar disposition and structure of the tissues composing them, lend themselves less readily than the muscles of others to the invasion of the putrefactive organisms. Itis well known that at even compara- tively low temperatures fish rapidly putrefy when the atmosphere is loaded with moisture, and that when the atmosphere is dry even at fairly high temperatures putrefaction is comparatively slow, and as dried gelatine is protected from the attacks of most organisms, by drying fish putrefaction is arrested generally in ratio to the complete- ness of the desiccation. It is scarcely necessary to point out the practical bearing of this inquiry. In fish putrefaction, when it once sets in, proceeds much more rapidly than in other vertebrates. This being the case, fish should be used as soon as possible after the rigor disappears. Inspectors of fish markets and fish dealers have various empirical tests by which they believe they are able to determine whether fish are or are not fit for food. They especially trust to the colour of the gills, the firmness and colour of the muscles, and the nature of the odour. As a matter of fact, it is often almost impossible to say whether a fish is or 1s not fresh after the rigor has disappeared. There is often a pause in the putrefactive process (caused probably by the first crop of bacteria being destroyed by their own bye-products). For this reason it is desirable fish should be used as soon as possible after the rigor has vanished, and that fish, intended for preservation (it matters little how), should be treated, if possible, while the rigor lasts. I have made numerous experiments with ice for preserving fish. It is generally alleged that fish which have been preserved for some time in a frozen state have lost much of their flavour. This I find depends partly on when the freezing is effected and partly on the temperature maintained. Fish which are frozen after the rigor has gone have either very little flavour or they are tainted with offensive septic products. But fish which have been frozen before rigor sets in (which have probably never stiffened) are equally without flavour, and they rapidly soften and disintegrate when raised to ordinary tempera- tures. On the other hand, fish which are frozen immediately after the rigor sets in remain almost unaltered, and when cooked can scarcely be distinguished from fresh fish unless the temperature has been unnecessarily low. The most perfect results were obtained by keeping fish (both salt and fresh water) at a temperature varying from —1° to —2° C. Haddocks which were pithed and gutted and preserved in water-tight insulated chambers ata temperature of —2°C. for three weeks continued rigid from first to last, and when cooked were firmer and better flavoured than ungutted fish only ten hours out. 458 Dr. J. C. Ewart. On Rigor Mortis in Fish. [June 16, of the water. For some reason not easily understood, the fish preserved in water at —1° C. were firmer and better in every way than fish at the same temperature in boxes from which the water escaped as the ice melted. Fish intended for drying and pickling, 7.e., for preserving for a long period, should also be treated before or as soon as possible after the rigor goes. When a fish has once begun to disintegrate it is impossible to restore the original freshness, and unless all the flavours are destroyed during the preserving process the results of previous decomposition can easily be detected. Some fish, as curers well know, are incapable of being preserved even with salt, e.g., fish which have died struggling in the water entangled in gill nets are difficult to preserve, because under these conditions, as experiments prove (probably in consequence of the acid reaction thus determined), no distinct rigor ever sets in—death being at once followed by putre- factive changes. Fish hitherto have usually either been lightly salted and sun-dried, or after being saturated with salt pickled in strong brine. A 20 per cent. salt solution almost completely alters the tissues. Apparently salt owes its preserving power to the fact that it arrests (though it fails to destroy) putrefactive organisms by a process of desiccation—ex- tracting the fluids, without which growth is impossible. Unfortunately we are acquainted with extremely few substances able in small quantities to arrest the growth of bacteria without rendering the fish unfit for food. It is extremely desirable to at least greatly diminish the amount of salt required. This has recently been rendered possible by a process introduced by Mr. Sahlstrom of the Normal Company. In this process the fish are introduced into a cylinder, and, after all the air has been removed by pumping, pressure (5 to 6 atmospheres) is applied to drive the preservative solution (which may contain salt alone, or salt along with other preserving reagents) into the tissues. I have made an extensive series of ex- periments by this method, and in all cases when fish in a rigid condition were treated, succeeded in arresting putrefactive changes, either per- manently or for a limited period according to the strength of the ‘solution used. This inquiry throws some light on another question which has long been discussed, viz., whether line-caught fish are preferable to fish taken by the beam trawl. In order finally to settle this question, it is only necessary to ascertain whether the rigor disappears quicker in the one case than in the other. I have already mentioned that a line- caught haddock, which has been killed and pithed the moment it leaves the water, may at a temperature of 8° C. remain stiff for 30 hours, 7.e., putrefaction may be retarded from 25—30 hours. On the other hand haddocks, captured by a 25-feet beam trawl which had only been two hours at work (large trawls are often down for six hours), even when 1887. Electrochemical Effects on Magnetising Iron. 459. killed and pithed immediately after taken from the net, may pass into rigor in 30 minutes and be again quite limp 6 hours after death. Sometimes, however, the rigor may not set in for 2 hours after the fish are landed, and it may continue for 17 hours, the difference doubtless resulting partly from the difference in the time the fish were in the trawl net, and partly from the energy expended in attempting to escape, or in endeavouring to maintain the respiratory movements under somewhat difficult circumstances. It may therefore be affirmed that though the rigor may persist as long or nearly as long in some trawled fish as in fish caught with a line, in most cases the rigor disappears sooner from trawled than from line-caught fish; in other words, putrefaction sets in sooner as a rule in fish taken by the trawl than in fish taken by the line, granting, of course, that the line fish are pithed and gutted as soon as they leave the water. __ IT have, in conclusion, to express my gratitude to Professor Burdon Sanderson and Mr. Gotch for valuable assistance rendered with the experiments made in the Oxford Physiological Laboratory. I am also indebted to Professor Tait for kindly allowing Mr. Lindsay, of the Natural Philosophy Laboratory in the University of Hdinburgh, to assist with the electrical experiments. I am further indebted to Mr. Clarkson, B.Sc., of the Natural History Department, Edinburgh, . and Mr. W. 1. Calderwood and Mr. Jamieson, Members of the Staff of the Fishery Board for Scotland. XXVI. “ Electrochemical Effects on Magnetising Iron.” By THomMAS ANDREWS, F.R.S.E., F.C.S. Communicated by Pro- fessor G. G. STOKES, P.R.S. Received June 2, 1887. Having for many years past been engaged in researches relating to the various aspects of the corrosion and oxidation of metals, nearly two years ago it occurred to me to investigate the probable effect of magnetisation on the relative electrochemical position of a pair of bright iron bars, one magnetised by a coil, the other un- magnetised, when thus simultaneously exposed in circuit, in a suit- able apparatus, to the action of various powerful oxidising agents and saline solutions. I accordingly specially prepared numerous long polished rods of soft wrought scrap iron 0°261 inch diameter, for use in the investigation. I was not able to commence the pre- liminary observations until towards the end of 1885, and, after much consideration and various trials then made, decided to adopt the following method of experimentation as perhaps calculated to yield the most delicate and accurate results; pressure of other work has, however, delayed the earlier completion of the work. The general 460 Mr. T. Andrews. [June 16 arrangement and methods of experimentation pursued are described below, and the apparatus is delineated on fig. 1 and fig. 2. Ee aS 7 Oltny—~ yo . "O72 5 ie ' — “Ee. a ' ~ = =a | 1, yyy Two pieces were adjacently cut from a long finely polished irou rod, so that the pieces might as near as practicable be of identical chemical composition and molecular constitution. After being firmly placed and adjusted as to equal length, &c., in the wooden supporting frame W, they were immersed to an exactly equal depth in the solu- tion contained in the U-tube, which latter was also rigidly supported by a stand. In the duplex experiments made with apparatus fig. 2, the U-tube was immersed in a large volume, four pints, of cold water to ensure equal temperature conditions during experimentation for the respective solutions in each limb, the cold water being maintained in steady circulation around the tubes. The rods were connected in circuit with a sensitive galvanometer, having a resistance of 521 ohms, and of known calibration, the galvanometer being under constant tele- scopic observation during the experiments, and the normal galvanic action between the two bars previously observed in every experiment. Considerable care was requisite to obtain this accurately, so as not practically to interfere with the subsequent results seemingly due to magnetic influences. A removable coil C, of stout silk-covered copper wire (No. 16 gauge) mounted on a large wooden bobbin 6 inches long enclosed the limb A of the U-tube, or when using apparatus fig. 2, 1887. ] Electrochemical Effects on Magnetising Iron. 461 the coil surrounding the upper portion of the long bar requiring magnetisation. The coil used in the experiments with apparatus fig. 1 consisted of six depths or wraps of the insulated copper wire, each wrap having 81 turns, making in the whole a coil of 486 convolutions. The other coil employed in the experiments with apparatus fig. 2 was of similar construction, but had ten depths of insulated copper wire of the same thickness, constituting a coil with a total of about 750 con- volutions. - A single cell bichromate battery, easily put in or out of operation, was attached to the coil, and the battery was recharged with the same strength of solution for each observation. After a suitable time had been allowed in each experiment for steady galvanic equilibrium to be established between the two iron rods, in the solution in the tubes, which took place at periods varying with the nature of the solution, the coil was put into operation. In the experiments with fig. 2 the end of the bar in the solution was the S seeking pole. It was most interesting to observe the result. The rod A thus magnetised in most of the solutions became the metal positive, the galvanometer indicating its steadily increasing electrochemical positive position compared with that of the unmagnetised bar B. Repeated careful experimentation appeared to indicate that the increased positivity of the rod A ob- served under these conditions was due to the increased action of the acid or saline solution on the iron rod which was under magnetic influence, owing to which it became surrounded by a slightly stronger saline solution than the other unmagnetised rod B, which was appa- rently less acted upon. In some cases in the more powerfully acid solutions, Table A, columns 4, 5, 7, 8, a kind of maximum point seemed to be generally reached, and after the more violent action of the acid had expended itself, a reduction of the H.M.F. between the rods was generally noticed as the solution in the B-tube gradually approached an equilibrium of composition compared with the solution in the A limb of the U-tube, and subsequently a reverse action in some cases was observed. The unmagnetised rod B appeared to be less rapidly acted upon than the one under magnetic influence. On maegnetisation of the bar the above full effect on the galvanometer was not always of an instantaneous character, though a short time only appeared requisite for its development. ‘The solutions employed are given in Table A, and the results therein recorded were derived from _ a series of constant observations, a. comparison in some instances being afforded between the respective effects obtained by the two forms of apparatus employed. It may be noticed that a fresh pair of the iron rods, cut adja- cently from a long polished rod, were used for each experiment, and 123 pairs were used in course of this part of the investigation, the whole of the experiments being many times repeated to ensure 462 My. 'T’. Andrews. [June 16, accuracy, the results recorded being the average of many observa- tions. In some instances somewhat higher results were noticed. It is almost’ impossible to obtain two pieces of iron (even when forming adjacent parts of one polished rod) which when in solution are devoid of some slight galvanic action between themselves; but the greatest care was exercised in the special preparation of the iron used, so that this variation might be reduced to a minimum. To ensure success in the experiments 1t was found essential that the iron bars should possess an excellent polished surface, free from mag- netic or other oxide or impurities; the solutions were also concen- trated, and both discrimination and manipulative skill were requisite in obtaining the practical galvanic equilibrium of the bars at com- mencement. The time needed to ensure this seemed to vary consider- ably with different solutions according to circumstances. A sensitive galvanometer was also a requisite of success in these observations, and telescopic readings were necessary, aS In some cases the effects were small. Tt seems desirable here to add a few remarks on the possible influence of temperature on the reactions, and to state the means used in the endeavour to minimise errors from this source. In con- ducting the experiments, I should have preferred using greater battery power, but employed only one bichromate cell; the wire of the coil was also of considerable thickness to prevent undue heating from resistance. The centre of the wooden coil bobbin was also about inch in thickness, so as to act as a central non-conductor. More- over, an air space was allowed of $ inch between the wooden centre of the coil and the enclosed limb of the U-tube. The other limb for the unmagnetised bar was enclosed by another coil, which, when not in use, acted as an external protective jacket. Notwithstanding these precautions, there was a slight increase of temperature in the interior of the coil C. Thermometers inserted in test solutions, one in each limb, gave an average difference of about 1° Fahrenheit at the end of an hour, this increase of temperature in the solution in the coil tube being, however, very gradual. It would be untenable to state that this difference of temperature, arising from the action of the coil, did not to some slight extent influence the results of the experiments with apparatus fig. 1; but the results obtained therewith could certainly not be regarded as due only to differences of temperature conditions between the two tubes. Most of the experiments with © that apparatus afford within themselves evident proof to the con- trary ; thus, it will be seen, that the magnetised bar assumed a pro- minent positive position almost immediately after magnetisation, in the case of nitric acid, before any perceptible difference of tempe- rature could obtain between the respective tubes (see Table A, columns 6 and 7). 1887.] Electrochemical Lffects on Magnetising Iron. 463 Moreover, the exceptional negative position of the magnetised bar under the same temperature conditions, in the case of sulphuric acid, affords evidence that the effect was not due to these temperature causes. ‘To more clearly demonstrate, however, that the results were mainly due to the influence of magnetisation, and acting on the kind suggestion of Professor G. G. Stokes, it was decided to make a duplex series of observations. I accordingly devised the modified form of apparatus fig. 2, which was intended to eliminate possible sources of error from temperature difference, by keeping the U-tube surrounded by a large volume of cold water during the experiments; the solution in the respective tubes being thus maintained under equal conditions. — In comparing the results obtained with the two forms of apparatus, it should be borne in mind that, when using the apparatus fig. 2, the cold water surrounding the U-tube would have a tendency to retard the increase of the temperature of the solutions naturally arising from chemical combination. Further, the coil in fig. 2 being at one end of the long bar would be calculated to modify the magnetisation of the other end of the metal in the solution, compared with its action in fig. 1, where the coil almost entirely surrounded the bar: hence in fig. 2, the coil was made somewhat larger to overcome this to some extent, and the end of the bar B was shortened in expe- riments with fig. 2, so that this bar would be less lable to be affected magnetically by the external intluence of the larger coil. I hope that the confirmatory results obtained in the two sets of observations may be considered as fairly satisfactory. VOL. XLIL. Ps 464 Mr. T. Andrews. [ June 16, Table A. E.M.F. in volt, and electrochemical position of magnetised bar compared with the unmagnetised bar, the positive or negative position of the former being respectively indicated by the signs + and —. Time from Fema A ses eee Column 1. Column 2. Column 38. Of Macheisation |. |. >) i e.. ae e in minutes. Potassium chlorate | Potassium chlorate | Potassium chlorate and one-fifth nitric | and one-third uitric| and hydrochloric acid. ‘acid. acid. I II I Th: I Il hrs. muns. 8) 0) 0-000 0°000 0-000 0 °000 0-000 0-000 0 1: af +0°004 | +0°014 | +0:°002 a ne 0 2 5 na Be +0°003 ce 4 6) 24 : +0:°006 | +0°014 |} +0-°004 es +0 °002 0 3 fe a: Eis +0 :°005 ole eis 8) 4, fe ie +0°016 | +0:°006 Ae ea 0) 5 +0°005 | +0:006 | +0:011 | +0°007 | +0°002 | +0:003 ) 6 ae i oe +0°007 an che 0 7 s si E Aas sn ois 0 7 é +0°004 | +0°011 | +0:008 ig + 0°006 0) 9 i: m8 Ag ag it td 0 10 +0°006 | +0°004 } +0°011 | +0:°008 | +0:°004 | +0-°004 6) ell 6 oi zit ne i és 0) 12 s : - 0 124 J ‘ it 6) 16) 4 A 0 14. sie ets 34 Se ae ais 0) Us +0°005 | +0:003 | +0°010 | +0°007 | +0°003 | +0:004 6) ives Se it ie +0°007 ae an 0 20 +0°006 | +0:°003 | +@°010 | +0°007 | +0°007 | +0°004 0 25 +0:°006 | +0:°003 | +0°010 | +0°007 | +0:°008 | +0:004 0 30 +0:007 | +0°002 | +0°010 | +0°009 | +0°007 | +0°008 0 35 +0:007 | +0:003 | +0°011 | +0:°006 | +0°009 | +0:°004 8) 40 +0:007 | +0:°003 | +0°011 | +0°006 | +0°008 |; +0:°006 8) 45 +0°008 | +0:°003 | +0°012 | +0:°005 | +0°007 | +0-°005 O 50 +0°009 | +0°002 | +0°011 | +0:°005 | +0:°006 | +0°005 0 5d +0:°008 | +0°003 |} +0°012 | +0:'005 | +0°007 | +0°006 1 8) +0°007 | +0°003 | +0°013 | +0°005 | +0°007 | +0°005 il 5 ae +0:005 ae +0 004 Se +0-009 il: 15 ss as an +0°005 aa +0:006 ot: 30 ae, +0007 AeA +0:°006 | +0:009 oh if 45 i +0006 ae bs +0°009 - 2 O ave +0005 5 +0°005 | +0:011 Column 1.—The potassium chlorate was a saturated solution of the salt, to which was added one-fifth of its volume of nitric acid of sp. gr. 1:388 at 60° F. Column 2.—The potassium chlorate was a saturated solution of the salt, to which was added one-half of its volume of nitric acid of sp. gr. 1°388. Column 3.—The potassium chlorate was a saturated solution, to which was added an equal volume of hydrochloric acid of sp. gr. 1:16. Column 4.—The potassium bi-chromate was a saturated solution, to which was added one-half of its volume of nitric acid of sp. gr. 1°388. Column 5.—The ferric chloride was a saturated solution, to which was added one- half of its volume of nitric acid of sp. gr. 1°388. . 1887.] Electrochemical Effects on Magnetising Iron. 465 Table A—continued. H.M.F. in volt, and electrochemical position of magnetised bar compared with the unmagnetised bar, the positive or negative position of the former being respectively indicated by the signs + and —. Time from Column 4. Column 5. | Column 6. commencement and duration aT of magnetisation eat | Roa: in minutes. eae Ferric chloride and | Nitric acid, sp. gr. 1°388, and nitric nitric acid. one part, and three alicia. parts water. II. I. Il. 103 1M, Pomesc) MINS, 0) (0) 0°000 0:000 0-000 0-000 0°000 0 1 ate ate —0°004 +0:°026 +0-°004 0) 2 +0:009 We +0 :002 ee és (0) 25 +0-°005 ale +0°002 +0:°020 +0°005 @) 3 +0°009 eS +0°O11 +0 ‘020 +0 ‘007 O A, +0°010 oe +0:°013 +0°016 | +0°CO9 0 5 +0007 +0°013 +0°014 +0:009 0 6 fe +0°020 ve -* (0) Pf ake +0°016 ae a 0 Wx ae ie +0:006 +0°011 +0:011 0 8 He ney +0°022 se aes VO 9 oe a +0°034 a +0°011 (0) 10 +0:°006 Ee +0°011 +0°008 +0°011 0 11 Pe ane +0°014 ae : @) ° 12 a, cits +0°011 fe Ws 0) 123 +0:°009 ae ih a +0:010 0 13 or ae +0009 at We 0 14 “ati ake BY Ae bg 0) 15 +0 :004 ae +0°002 +0°009 +0:005 0 16 ee i A ae : 0 ly § 5 - ws a. Ay 0) 7; He re +0009 & ae 0) 19 Ae ms sil Be a 6) 20 +0°007 +0 :009 +0°'007 +0:007 +0:005 (0) 224 a ute a 545 a6 0 25 +0:°005 +0:018 +0:°004 +0°001 + 0-003 0) 30 +0:°003 +0038 +0°002 +0°001 + 0-004, 0 35 +0:001 +0°038 +0:°008 +0°O11 +0°004 0 AO +0:°004 +0-023 +0°002 +0°012 +0 °004 O 45 +0:001 +0:°002 . we +0°018 + 0: 004 @) 50 +0:002 +U°004 ae +0°009 +0:°006 (0) 55 ay +0:005 wh +0°012 +0007 1 0) +0°006 +0°006 +0°001 +0°013 +0:007 1h 5 ae . we te fe ip 15 ae J 1 30 ae aie ale 1 45 os 6 2 0 ‘ +0°007 2 20 Ne 3 O es we ae ae ave 3 15 ae a Pee ai ate pal Gy ey 466 | Mr. T. Andrews. © [June 16, Table A—continued. E.M.F. in volt, and electrochemical position of magnetised bar compared with the unmagnetised bar, the positive or negative position of the former being respectively indicated by the signs + and —. ; Column 7. Column 8. | Column 9. Column 10. Time from commencement and duration oa of magnetisation me Tee, Hydro- in minutes. Nitric Acid, HNO, and chloric acid, Sulphuric ead sp. gr. 1-388, sp. gr. 1°16, 1 part, and 4 parts cae 4 . 1, | Gilated to (concentrated), water. Pe oie one-half sp. gr. 1°84. ee with water. I II II be if II hrs. mins. 0) 0) 0:000 | 0:000 0°000 0-000 0:000 |} 0-000 0 if 4% +0°004 | +0°002 ste ate i 8) 23 we +0°006 a oe He —0:001 (8) 3 + 0-009 aie aa “ Ay cat 0 A, 58 +0°012 8 oe a3 ae (0) 5 +0°012 |+0°011 | +0:°004 —0:0004 |—0°003 |—0-°002 0) 6 ie +0°010 i es Bs ant 0 Ts +0:°007 | +0-°006 ar 0 9 se est Ay ae oe s,. 8) 10 +0°011 |+0°003 | +0:011 —0°'001 |—0:°004 |—0°0038 0 11 on +0005 as as ais ca 0 12 ae +0°005 | +0:°013 re oe es 0 1234 Ay . Ay Ae Pa Be 0) 13 ee +0:°005 aie - au P 8) 14 Pies +0:°003 | +0-014 a us is 0) 15 +0:'0138 |+0°001 | +0-:027 —0:001 |—0-°005 |—0-005 0) 16 as ies +0027 ee as a 0 il) ae aia +0°014 0 19 ss oe ue ee ws ue 0) 20 +0°014 |+0°004 | +0°025 —0:001 |—0:006 |—0°005 0 223 fF, ars +0°010 —0:001 Lhe aa 0 25 +0:'0138 | +0 :004 Me —0-001 —0°005 |—0:006 0 30 +0°'012 |+0°005 | +0-004 —0:001 |—0-:007 |—0-006 0 35 +0°013 |+0°005 oN —0:001 |—0:008 |—0-°006 8) 4.0 +0°012 |+0°004 ei —0:‘001 |—0°009 |—0:°006 0 AD5 +-0'012 |+0°003 | +0-001 —0:001 |—0-°011 |—0-005 0 50 +0°012 |}+0-003 Le —0°001 |—0°012 ;,—0:005 0) 55 +0'012 |+0-004 +0:001 —0-002 —0:014 |—0:006 if @) +0°011 |+0:004 +0-001 —0°002 —0°016 |—0:-006 if i a Hy Ye —0:'003 |—0:022 |—0-007 ib 30 ais ote ae —0°002 —0°022 |—0°008 iL 45 “a ties BC — 0-004 aus —0 ‘008 2g 0 His aS of —0°004 a —0 ‘009 2 20 oe ie she —0 028 3 0 ; ae ee —0:009 o 15 He —0°021 1887. | Electrochemical Effects on Magnetising Iron. 467 The records in the above table under divisions I were experiments made with apparatus, fig. 1, the records entered under divisions II, relate to observations made with apparatus, fig. 2. The records of the effects in the stronger solutions do not indicate the full extent of the electric action compared with that of the weaker solutions ; because in the former case the tubes could only be par- tially filled, so as to prevent boiling over. General Remarks. Potassium Chlorate and Nitric Acid Solutions, Columns 1 and 2.— At the termination of some of these experiments, the depth of colour of the solution surrounding the magnetised iron was perceptibly of a darker shade than the colour in the tube surrounding the un- magnetised bar, this was confirmed by HEggertz’s carbon coloration test, Ferrie Chloride and Nitric Acid, Column 5.—At forty minutes from the commencement of one experiment in apparatus fig. 1, the record was an H.M.F. of 0-023 volt, the magnetised bar being positive; the battery was then attached to a smaller coil surrounding the other bar B, which was then magnetised instead of the bar A, and in course of five minutes a reduction in the positive position of bar A to an extent of 0:021 volt occurred. At forty-five minutes the battery was reconnected to the coil surrounding the bar A, producing a steady increase of positive position in that bar as recorded in Table A, column 5. Aqua Regia, undiluted—With this reagent in fig. 1 no very decided galvanic reaction took place until the bar had remained magnetised for some ten minutes, when violent effervescence occurred accompanied by evolution of dense reddish-brown fumes, the magne- tised bar then becoming rapidly electropositive to an extent yielding an H.M.F’. of about 0'110 volt. This position was subsequently more or less maintained for some ten minutes, the galvanometer, however, gradually falling to zero as the ebullition in both tubes subsided. This was a difficult experiment to make, owing to the very violent effervescence. Aqua Regia, diluted, Column 8.—Up to the commencement of the effervescence no perceptible difference in the colour of the solution in the respective limbs of the U-tube was noticed ; but immediately on the violent ebullition occurring, which took place generally about ten minutes from commencement, the solution surrounding the mage- tised bar frequently became of a very much darker tint. This marked difference between the colour of the respective solutions in the two tubes was maintained for some time, afterwards the two solutions became apparently nearly chromatically equal. The electro- 468 Electrochemical Effects on Magnetising Iron. [June 16, chemical effect appeared to be less marked when using aqua regia containing excess of HCl. The relative electrochemical position of the two bars in such case being less divergent, the HCl appearing to act somewhat as a strong diluent. Hydrochloric Acid and Sulphuric Acid, Gola 9 and 10.—Singular to say, the previously described magnetochemical effects were com- paratively small when using such a powerful reagent as hydrochloric acid alone, either concentrated (sp. gr. 1:16) or diluted. When this acid was employed in conjunction with concentrated solution of potassium chlorate (Table A, column 3), the effects there recorded appeared due rather to the oxidising agency of the evolved chloric compounds; in the presence of magnetism, the reactions with this electrolyte were occasionally irregular, the excess of HCl appearing sometimes to interfere. Sulphuric acid, conc., also seemed to behave abnormally, though this acid does not ordinarily act strongly on iron. The experiments with both the above acids in course of a large number of observations, proved exceptions to the general rule. The magnetised bar in the sulphuric acid, conc., and also in the hydro- chloric acid, diluted, became the eetronesatl tive metal, not only in the case of H,SQO,, when using the apparatus fig. 1, but also when experimenting with the modified form, fig. 2. Occasionally, with sulphuric acid, conc., the magnetised bar was, on first magnetising it, shghtly Se Geet for a few minutes only; but afterwards became steadily negative. Under the conditions of experimentation, the magnetised bars in the powerful oxidising reagents used almost invariably assumed the electropositive position, the presence of H.NO; appearing essential to the full development of the positive position of the bar under the influence of magnetism. On the contrary, the magnetised baz seemed to be the electronegative metal in H.SQ,, conc., and also in the HCl (diluted), as eiectrolytes. The two latter reagents by their action on the metal generate gases of a reducing character. These exceptions are not, however, averse to the principle that magnetisa- tion exerts an influence on the relative electrochemical position of a pair of iron bars, varying according to the nature of the solution and the extent to which one of them is magnetised. In the above excep- tions, it is possible that the magnetised bar assumed the negative position consequent on its being the one more attacked, under magnetic influences, by the reagent; thus producing a greater evolu- tion of reducing gases in the tube A containing the magnetised bar than in the other tube; this may perhaps explain the negative effect. The observations of this memoir therefore indicate that, under the powerful and rapidly oxidising conditions described, a magnetised bar becomes metal positive to an unmagnetised one, whereas in the exceptional instances above alluded to, the electronegative effect 1887.] The Sinuses of Valsalva and Auricular Appendices. 469 occurs, pessibly owing to the presence in the solution of such reducing agents as nascent hydrogen, &c. In the present incomplete stage of the enquiry these remarks are only offered tentatively. The effects could not be expected to be large; I anticipate, however, generally more marked results in a more powerful magnetic field, exerting its influence, perhaps, for longer periods; but I think the experiments now submitted appear sufficient at least to afford an indication that, under the conditions recorded, magnetisation exerts on iron, in some solutions, an appreciable effect. The results already obtained in this direction are so far interesting as to encourage further research into the nature of this novel and subtle phenomenon. XX VII. “Note on the Functions of the Sinuses of Valsalva and Auricular Appendices, with some Remarks on the Mechanism of the Heart and Pulse.” By M. Cottier. Communicated by Victor Horsuey, F.R.S., Professor Superintendent of the Brown Institution. Received June 9, 1887. (Abstract.) The object of the paper is to disprove the present apparently accepted idea, that the sinuses of Valsalva are mere bulgings of the arterial walls, formed by a reflex current induced by the sudden closure of the semilunar valves. The existence of a reflex current is shown to be impossible, and the theory of the sudden opening and closure of the semilunar valves is strongly opposed. The presence of the sinuses of Valsalva is urged as an absolute essential to the mechanism of the heart’s action. The paper then treats of the action of the auricle and the part played by the auricular appendix, the latter being considered as the only part of the anricle that sensibly and vigorously contracts. The causes of the first sound of the heart are next alluded to, and the theory that the closure and vibration of the tricuspid and mitral valves assist in its production is refuted. The action of the ventricle and the mode of the injection of its contents into the aorta is dwelt upon at some length. The latter part of the paper is devoted to the mechanism of the pulse, and an explanation is given of the so-called dicrotism. The paper terminates with a summary of the chief points of the conclusions arrived at. At> ie | ee i & . he A70 Messrs. J. J. Sylvester and J. Hammond. [June 16, XXVIII. “On Hamilton’s Numbers.” By J. J. SYLVESTER, F.R.S., Savilian Professor of Geometry in the University of Oxford, and JAMES Hammonp, M.A. Cant. Received June 11, 1887, (Abstract. ) In the year 1786 Erland Samuel Bring, Professor at the University of Lund in Sweden, discovered that by tie method of Tschirnhausen it was possible to deprive the general algebraical equation of the 5th degree of three of its terms without solving an equation higher than the 3rd degree. By a well understood, however singular, academical fiction, this discovery was imputed by him to one of his own pupils, one Sven Gustaf Sommelius, and embodied in a thesis humbly sub- mitted to himself for approval by that pupil, as a preliminary to his obtaining his degree of Doctor of Philosophy in the University.* It seems to have been overlooked or forgotten, and was subsequently re-discovered many years later by Mr. Jerrard. In a report contained in the ‘ Proceedings of the British Association’ for 1836, Sir William Hamilton showed that Mr. Jerrard was mistaken in supposing that the method was adequate to taking away more than three terms of the equation of the 5th degree, but supplemented this somewhat unneces- sary refutation by a profound and original discussion of a question raised by Mr. Jerrard, as to the number of variables required in order that any system of equations of given degrees in those variables shall admit of being satisfied without solving any equation of a degree higher than the highest of the given degrees. In the year 1886 the senior author of this memoir showed in a paper in Kronecker’s (better known as Crelle’s) ‘Journal’ that the trinomial equation of the 5th degree, upon which by Bring’s method the general equation of that degree:can be made to depend, has necessarily imaginary coefficients except in the case where four of the | roots of the original equation are imaginary, and also pointed out a method of obtaining the absolute minimum degree M of an equation from which any given number of specified terms can be taken away subject to the condition of not having to solve any equation of a * Bring’s Reduction of the Quintic Equation was republished by Mr. Robert Harley, F.R.S., in the ‘ Quarterly Journal of Pure and Applied Mathematics,’ vol. 6, 1864, p. 45. The full title of the Lund Thesis, as given by Mr. Harley (see ‘Quart. Journ. Math.,’ pp. 44, 45) is as follows: “ B. cum D. Meietemata quaedam mathematica circa transformationem aequationum algebraicarum, quae consent. Ampliss. Facult. Philos. in Regia Academia Carolina Praeside D. Erland Sam. Bring, Hist. Profess. Reg. & Ord. publico Eruditorum Examini modeste subjicit Sven Gustaf Sommelius, Stipendiarius Regius & Palmcrentzianus Lundensis. Die x1v Decemb., MpccLxxxvi, L.H.Q.S.—Lundae, typis Berlingianis.” 1887. | On Hamilton's Numbers. A471 degree higher than M. The numbers furnished by Hamilton’s method, it is to be observed, are not minima unless a more stringent condition than this is substituted, viz., that the system of equations which have to be resolved in order to take away the proposed terms shall be the simplest possible, i.e, of the lowest possible weight and not merely of the lowest order; in the memoir in ‘Crelle’ above referred to, he has explained in what sense the words weight and order are here employed. He has given the name of Hamilton’s Numbers to these relative minima (minima, 7.e., in regard to weight), for the case where the terms to be taken away from the equation occupy consecutive places in it, beginning with the second. Mr. James Hammond has quite recently discovered by the method of generating functions a very simple formula of reduction, or scale of relation, whereby any one of these numbers may be expressed in terms of those that precede it: his investigation, which constitutes its most valuable portion, will be found in the second section of this paper. The principal results obtained by its senior author conse- quential in great measure to Mr. Hammond’s remarkable and unex- pected discovery, refer to the proof of a theorem left undemonstrated in the memoir in ‘Crelle’ above referred to, and the establishment of certain other asymptotic laws to which Hamilton’s Numbers and their differences are subject, by a mixed kind of reasoning, in the main apodictic, but in part also founded on observation. It thus became necessary to calculate out the 10th Hamiltonian Number, which contains 43 places of figures. The highest number calculated by Hamilton (the 6th) was the number 923, which comes third in order after 5 (the Bring number), 11 and 47 being the two intervening numbers. It is to be hoped that yome one will be found willing to undertake the labour (considerable but not overwhelming) of calcu- lating some further numbers in the scale, in order to establish or disprove conclusively the presumptive law of the asymptotic branch of the series connecting any two consecutive semi-differences 92, yx41 of the Hamiltonian Numbers, viz. :— r=@ 1\7 Qe — 2 = jipaGs 9 Or Ia 2 The theory has been ‘“‘a plant of slow growth.’ The Lund Thesis of December, 1786 (a matter of a couple of pages), Hamilton’s Report of 1836, with the tract of Mr. Jerrard therein referred to, and the memoir in ‘ Crelle’ of December, 1886, constitute as far as the senior author of this paper is aware, the complete bibliography of the subject up to the present date. 472 On the Induction of the Explosive Wave, ke. [J une 16, X XIX. “On the Induction of the Explosive Wave and an Altered Gaseous Condition in an Explosive Gaseous Mixture by a Vibratory Movement.” By Lewis T. Wricut. Com- municated by Professor ODLING, F.R.S. Received June 13, 1887. (Abstract.) The author refers to the conclusions of Berthelot and Vieille that the phenomenon of the explosive wave is quite distinct from that of ordinary combustion, each being marked by well-defined limits called by them the régime of detonation and combustion respectively. The transition from the one to the other is accompanied by violent vibra- tory movements. Mallard and Le Chatelier separate the combustion of an explosive mixture inflamed at the open end of a tube, closed at the other, into four different and succeeding phases— (1.) Uniform propagation of flame ; (2.) A vibratory movement; followed in some cases by (3.) The explosive wave of Berthelot and Vieille. (4.) Spontaneous extinction of flame. The author has specially studied the connexion between the vibrating stage and the explosive wave with a certain mixture of coal gas and air (in large glass tubes) which sharply exhibits the various features of the four stages described by Mallard and Le Chatelier. The points determined were these, that the detonating stage (explo- Sive wave) is never initiated without preceding vibratory movements on the part of the flames. That with the same mixture the vibrating period is of definite — duration culminating in the explosive wave stage. The necessary connexion between the two stages being proved, the author investigated the question whether the explosive wave condition is communicated layer by layer by the contact of the flame itself, or whether the whole column of unignited gas in the tube adjacent or distant from the flame is ‘‘induced” by the vibrating flame into a more receptive condition which enables the chemical reaction between tbe molecules to proceed at a more rapid rate than usual, The phenomena exhibited by the flame suggest this latter explana- tion, and the author by the application of a weak spark test has been enabled to prove that the whole column of gas, either adjacent or dis- tant from the vibrating flame, is in an altered condition after being submitted to but a portion of the vibratory action which normally initiates the explosive wave. 1887. | On a Balanoglossus Larva from the Bahamas. 473 An electric spark of low tension not capable of igniting the unin- duced explosive mixture invariably does so, after the vibrating has been set up. It is suggested that the tremor sent through the unignited gas synchronised some of the molecular vibrations, so that the molecules capable of reacting perform their translatory movements in some measure together, and that when a focus of inflammation is present more reacting molecules come into the sphere of inflammation in a given time, and therefore the rate of inflammation is more rapid. XXX. “ Note on Communication entitled ‘Preliminary Note on a Balanoglossus Larva from the Bahamas’ (‘ Roy. Soe. Proe.,’ vol. 42, p. 146).”. By W. F. R. WeLpon, M.A. Communi- cated by Professor M. Fostmr, Sec.R.S. Received June 16, 1887. In a paper, communicated to the Royal Society in March last, I described a series of Balanoglossus larve, found by me in the Bahama Islands. The series extended from a larva with one pair of gill-slits toa form resembling in many ways a normal Tornaria; but the dif- ferences between this larva and the normal Huropean form were so ereat as to induce me to believe that a process of degeneration was going on, and that the Tornaria-like creature was the oldest, not the youngest, of the series. On seeing my paper, Professor Spengel, whose researches on Balanoglossus are well known, wrote to me, informing me that I was altogether mistaken in my interpretation of the larve which I had found, and that my series belonged in fact to the normal order of development. By the courtesy of Dr. Spengel I have been enabled to inspect his magnificent series of preparations, illustrating the whole life-history of Balanoglossus, and so to become convinced of the truth of his statement; I now, therefore, take the earliest opportunity of with- drawing my previous statement, and. desire to express my regret at _having placed such an erroneous doctrine on record in the ‘ Pro- ceedings’ of the Society. I beg also to thank Dr. Spengel most sincerely for his kindness to me in this matter, ATA Mr. C. 8. Sherrington. [June 16, XXXI. “Note on the Anatomy of Asiatic Cholera as exemplified in Cases occurring in Italy in 1886.” By CHARLES S. SHERRINGTON, M.B., M.A. Communicated by Professor M. Foster, Sec. R.S. Received June 16, 1887. Last summer when cholera again appeared in Italy I determined to seize the opportunity that seemed to offer itself for re-examining the disease, especially with regard to some questions raised by the work of the previous year. Although, on grounds which I have already detailed in a letter to the Secretary of the Society, Professor Michael Foster, the conditions imposed by the state of the country quite precluded the carrying out there and then of trustworthy experiments with the living contents of the dejecta and of the viscera of the cholera patients, still it was possible to collect a satisfactory amount of anatomical material. The results in this direction of an expedition, a part of the expenses of which were generously borne by the Society, were promised to the Society in the letter above alluded to. The investigation of the material has now been completed, and may briefly be stated as follows :— The material collected consists in all of specimens and preparations made from twenty-five fatal cases. Of these cases twenty-two were indubitable examples of rapidly fatal cholera asiatica. These were obtained exclusively out of the Province of Puglia. The remaining three cases were from Venetia, and were in the opinion of myself and Dr. Rouse, who in Venetia assisted me, not examples of true cholera. At each autopsy the specimens taken for preservation and subsequent detailed microscopical investigation were portions of the stomach and intestinal canal at various points, of the thoracic and abdominal organs, and of the mesenteric glands. From the contents of the stomach and intestine preparations for the microscope were made at the same time by the Hhrlich-Koch method. From the yomit and dejecta of six moribund patients cover-glass preparations were also made in the same manner. With regard to the hardening of the tissues for microscopical examination, the portions of the tissue preserved were at the autopsy carefully placed separately into speci- . men glasses containing absolute alcohol, and the alcohol was at the end of six hours renewed, the specimen being at the same time quickly cut into pieces never more than 3 mm, thick. The alcohol was then changed at the end of twelve hours, and again at the end of twenty- four, then not again for a week. The microscopical investigation has been carried on in the labora- tory of Professor Virchow at Berlin; in his debt I stand for much kindness and liberality. | | 1887.] On the Anatomy of Asiatic Cholera. 475 One of the main objects of the renewed inquiry was to ascertain the presence in, or the absence from, the anatomy of cases of cholera from another epidemic than the Spanish of certain appearances that the microscopical preparations from the Spanish epidemic of 1885 had presented. The appearances referred to were described in a Report made to the Society in June of Jast year, and printed in the Proceed- ings of the Society for that year, so that it is unnecessary for me to repeat them here. The more so since in this year’s work I have com- pletely failed after minute, long and repeated search, with the use of good lenses (new apochromatic system of Zeiss), and after employ- ment of various methods of staining including that by which the Spanish preparations were coloured, to find any trace of the above- mentioned appearances in any of the material obtained in Italy. Neither in the specimens of the tissues nor of the intestinal fluid post mortem, nor of the vomit or dejecta during life is any trace of them to be found. Any view that suggested itself of a causal con- nexion of them with cholera must therefore meet the difficulty that they form no constant anatomical feature of the disease. With regard to the presence of comma-shaped bacilli in my material, such forms have been found in altogether thirteen of the cases from Puglia, although always with difficulty, and seven times only after extremely patient and rigorous search. The method found most satisfactory for their detection has been that of Loffler with a methylene-blue solution made according to the receipt given by him. The chief difficulties of the investigation have laiu in the facts, that the comma-bacilli are among the bacilli which are earliest decolorised by the solutions for removing the excess of stain, that the morpho- logical characters of the comma-bacilli are not so distinctive as to make their recognition from bacilli of some other species always certain, and that in none of my specimens have I found them free from admixture with other micro-organisms, and in none in very great abundance. Having only the morphological characters of the bacilli for criterion, I have compared them always with specimens from pure cultivations of Koch’s comma-bacillus freshly prepared for the purpose, and I have only accepted them as such when they have agreed with the latter standard form. Of the cases in which the comma- bacilli have been itn in three they may be called ‘‘ fairly numerous,” in five ‘‘ sparse,”’ and in five ‘* very scanty. ” The bacilli have never been found in any other situa- tion than in the wall of the alimentary canal, and in the wall only in the most superficial portion of the tissue, in the mucosa. The three cases in which they are fairly numerous are characterised clinically by the fatal ending having supervened without any stage of febrile reaction, and anatomically by the changes in the wall of the intestine being confined to partial denudation from epithelium of the 476 On the Anatomy of Asiatic Cholera. [June 16, villi, especially, to the presence of an excessive number of leucocytes in the meshes of the mucosa and submucosa, and to evident engorge-_ ment of the portal venules. The comma-shaped bacilli lie in the fundi of the tubular glands of, especially, the ileum, and in the tissue in which those glands are imbedded in the inmediate vicinity of the glands. Their distribution is not uniform, but is patchy. They occur with various other forms of bacteria in the same situation. Generally — of these other forms some have penetrated more deeply into the tissue than have the comma-bacilli; especially is this true of certain fine, straight bacilli resembling morphologically the bacterium coli com- mune of Hscherich. In the other cases in which comma-bacilli are found, the signs of acute severe inflammation are more obvious, many of the denuded villi are in part necrotic. Shallow sloughs occupy the surface’ of the mucous membrane, together with small extravasations and patches of “‘coagulation-necrosis.”’ Here the comma-shaped bacilli are within the mucosa, and with them occur a multitude of micrococci and bacilli of various shape and size. Although in two of these cases bacilli are to be seen in the distended venules, I have in no instance found comma-bacilli within any blood-vessel. Of those cases in which comma-bacilli have not been found, the impression left upon me is that in some of them it is possible that still further examination of a still more extended series of prepara- tions from them might have revealed comma-bacilli in the wall of the intestine in some of them. They are all cases that, although of rapidly fatal issue, had passed into a stage of febrile reaction. In them often the surface of the ileum and large intestine was thickly set with little patches of superficial sloughing, and micro- scopical preparations made through these areas forcibly recall prepara- tions of a mucous membrane diphtheritically inflamed. The attached face of the slough is occupied frequently by an almost continuous sheet of bacteria, and bacteria infiltrate the inflamed submucosa, and often the superficial regions of the muscularis. In three of these cases micro-organisms are present in the blood-vessels, more Sa fod a numerously in the venules of the portal system. With regard to the preparations made from freshly evacuated dejecta and vomit from living cases, the six cases examined reveal comma-bacilli in the stools in five. There is no evidence of blood in these five stools, but blood is mixed with the intestinal fluid in the case in which no comma-bacilli are seen. The vomit also in three of the cases shows a small number of comma-bacilli. In none of the preparations do the comma-bacilli make up more than a small fraction of all the bacterial forms present. With regard to the statement by Cohnheim that the shedding of the intestinal epithelium is purely and merely a process setting in 1887. | On certain Definite Integrals. ah post mortem, this, which has always been denied by Virchow and others, is negatived by the occurrence in the stools here examined of an abundance of epithelial cells, often very slightly differing in appearance from the normal. Occasionally they are coherent as groups of four and five; there are, however, no finger-shaped casts of complete villi. The cases of a doubtful nature from Venetia have not disclosed any comma-bacilli under microscopical examination. In one of them the ulcers present in the ileum, which to the naked eye resembled those of enteric fever, pass deeply into the thickness of the muscular coat of the intestine, a condition to which I have only once seen any close approach in Asiatic cholera. XXXIT. “On certain Definite Integrals. No. 15.” By W. H. L. RUSSELL, F.R.S. Received June 16, 1887. Mr. Fox Talbot’s researches on the comparison of transcendents are well known. The following are founded on the same principle, applied in a different manner :— Let— a,x + by +eo22 = e, Ayx® + boy? +922 = ep, be two equations connecting the variables x, y, and z. Then we can find # and y in terms of z, 2 and z in terms of y, y and z in terms of (x). Or if— and also €) Ay — €9 A, = A», €)b3— gb, = Ba, €1 0g — C96] = Cy; we shall have = eet /(B,+ A, 2°), VY (C1) y= gy MB) VW (Cy) ee 1 a (By) J (A,+Cyy’), 478 Mr. W. H. L. Russeil. [June 16, t= yg CG Aw), watt 1 8 3 y= Mien ); Now, since > [a . 2y-+ ‘ cis Ly —— wee AST (B,C) dx x/(C, + B,z*) ./(By— C,2*) Ag : (Acy}| die &/ (Ay + Cya) 97 (Cy—Aa’) Me +(AB,)'|"“de /(By-+ Aya?) /(Ay— By’) «Ve a (A,B,C })*Agpgrg— Ay") where the limits \,\,4,4.»,v, must satisfy the equations— arpthwrtoqy? = 4, AyAo> + Dy py? + Cov? = 95 Aghy? + bony? + C9r2? = eo, Agho> + bobo? + Coro? = Cy} from which it appears that one pair of limits may be considered arbi- trary, while the other two pairs are given by these equations. Since— aC ee + cae eye \ayre | \ eye xyz da - ab | / (Cy + Bye’) YC J (Bo —C,2%) da ip V/(Agt x? 4/ (Ag+ C,24) 1) 7 (C,— Aya) ne dx oh ms 9/(By+ Aya) 4/(Ag—Bya') = Nyp171 —AgtoYo, the limits being determined as before; and since— 1887. | On certain Definite Integrals. A479 (de _fedy fee _ ae ey ye Pde y= Aa), Pde Y (Bat A) Ws w ¥/(A,+ O23) 5 a? X/(A,— B, x?) g mewonbeleD Ap ait 2s by ty Ral) aber ie J (Cy + Bia?) ¥/ (B,— C2") Hy) b] Pov —A, moreover, since ot eee | Yap oe [east dz [Sa = eg (Apa) 10% 5 .0Chaean Bi) we shall have | a we = a | @ Y(By + Aya) 1(* 7 (C,+B,23) /(B,—Cya?) __ oe 1 x irra Me bf BQv2 YY) Again, since | yp +5| dy yPo42| dz ay? = ay>2z?, 2a2B, (A), |» de (B,+Ay2?)\(4.—Bye") +5A,°C,/? vay| da x*(A,+C,x*)*(C,—A,a3)3 —B,C? | de (Cy + By23)i(B,— ©, 23)? = APB Cy? (Az) (rottg? 2a? — Ayu?) Similarly, since lore de+| (w+) iy +| (w+y)dz = cy+ae+yz, 1B,)| ds { /(Cy+ Bx) — 3/(B,—Cya%)} ue MAC)| da { &/ (Ag +C,23) — /(Cg— Aya?) } iy Y(AB))| de { 3/(B-+ Aya®) — /(Ay—By28)} = 2/(A,BiC,){ Brg —ZAyuy }. VOL. XLII. 480 Mr. W. H. L. Russell. [June 16, Next suppose that we transform by aienay of the equations— netbytoz = &, Apt + boy + 6,2 = eo, and remember that ¢,, ¢,, 63 being any functions— [ae py () Poly) oye dy boy P(@) $3(4) x | da hs'(2) (a) bly) = bv doy bye then, transforming as before (with similar limits), B \¢—B | ae dy'(2) oa i ~B, 1 +| dx hy (x) o3 ate a als By +| in 670) gh ee ae b Cy = $y Potty Pav2— Pho Potto Psa» we observe there are three arbitrary functions, which can be taken at pleasure, and six arbitrary constants. We perceive therefore that the formula is very extensive. The limits are of course connected by the equations— Oy +b + = 4, Arg + Dyag+e¥o = &, Aghy + bom +07) = | ® > Next let us transform by means of the equations— a,(a?—2ma) + b,(y?—2my) + o(2?—2vz) = ae, a(x?—~Q2mx) + bo(y?—B@my) + co(2*—2vz) = &; then, proceeding as hefore,— BLOS i.) On certain Definite Integrals. 481 B, 2rA A,2 3 2 = m+ jmta— ae | ; ce ©; C; Q:) 3 ee ie a os \ 2) 3 97) 3 2 = m+ a8 © mare \ ; B, Pe votes age | oS 3M, on 5 \ aa” B, 2mC C is a Da ae ] 172 ; 2 bar : r ig ne = ae Hence we have the sum of the integrals (supposed to be taken within the proper limits)— > somes | dx {m2 += +A \ 1 C, C’ A, 2rB B = a a 1 1 i" BO? OT MOG A, 2nC C aN al a 1 1 +| t Tit, B, By C, 2mB, jl Vp a NS +| a : Cag Te aw expressed by elliptic functions. As a final example take the following :— Let— a,x? -+ by? Pee? = e, ane? + boyP + coe = e. Then since —- Pp | da yet |dy wz +| Gaia — 0/2, 482 Deferred Papers. [June 16, BNC) | de §/(Cy+Bya) 8/(By— Oya) + 9/(A,80,8) | ae 3/(Ag+ Oya) 2/(Cy— Aya’) + 7(BMA,)| dx /(Bo+ Aya?) /(A,— Ba) = ys (ASBG,®) (Noftg Vor M4 v)) 7 If we put | de yew | dy ww + dz xy w+ (dw . LyZ = xyzw, and transformed by three equations similar mutatis mutandis to those we have have used, we should of course obtain the sum of four definite integrals. The limits are omitted in some of these equations, but they will be easily seen from the foregoing. XXXII. “A Geometrical Interpretation of the first two Periods of Chemical Elements following Hydrogen, showing the Relations of the fourteen Elements to each other and to Hydrogen by means of a Right Line and Cubic Curve with one real Asymptote.” By Rev. SamMuEL HaucutTon, M.D., F.R.S. Received April 30, 1887. [Publication deferred. ] XXXIV. “On the Force with which the two Layers of the healthy Pleura cohere.” By SamurEL WEst, M.D., F.R.C.P. Communicated by Su JAMES PAGET, Bart., F.R.S. Re- ceived May 21, 1887. [Publication deferred. ] XXXV. “Total Eclipse of the Sun observed at the Caroline Islands on May 6, 1883.” By W. DE W. ABNEY, Capt. R.E., F.R.S. Received May 25, 1887. [ Publication deferred. | 1887. ] Presents. 483 XXXVI. “Note on Mr. Davison’s Paper on the Straining of the Earth’s Crust in Cooling.” By G. H. Darwin, M.A., F.R.S., Plumian Professor of Astronomy and Experimental Philo- sophy in the University of Cambridge. Received June 15, 1887. [To be published in the ‘ Philosophical Transactions,’ in conjunction with Mr. Davison’s paper. ] XXXVII. “A further minute Analysis, by Electric Stimulation, of the so-called Motor Region of the Cortex Cerebri in the Monkey (Macacus sinicus).” By CHARLES E. BEEvor, M.D., gud Professor VICTOR Horsiry, F.R.S., B.S., F.R.C.S. Abstract received June 16, 1887. [ Publication deferred. | XXXVIII. “On the present Position of the Question of the Sources of the Nitrogen of Vegetation, with some new Results, and preliminary Notice of new Lines of Investiga- met) by. sir J.B Lawes, Bart. F.R.S.,,andy J. Hy GILBERT, M.A., LL.D., F.R.S., Stbthorpian Professor of Rural Economy in the University of Oxford. Abstract received June 16, 1887. [Publication deferred. | XXXIX. “On Diameters of Plane Cubics.” By Joun J. Waker, M.A., F.R.S. Received June 16, 1887. 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Owing to the uncertainty prevailing as to the continuous exten- sibility of ice under tensional stress, it appeared to me desirable to institute a series of experiments directed to this point, conducted according to the methods, and, as far as possible, with the exactness of modern experimental testing. In order to eliminate the influence of regelation, the experiments have been carried on at such low temperatures as preclude the possi- bility of any effect being produced by this cause, the highest tem- perature recorded in Experiment No. 1 being —2°6° C.; in No. 2, —1-:0° C.; and in No. 3, —0°5° C. It must be remarked, moreover, that these maximum temperatures only obtained for a very short time, on one or two days, as will be seen from the records. The testing machine which I used was constructed for me by Herr Ingenieur Usteri-Reinacher, of Ztirich. It was on the com- pound lever principle, the ratio of the arms of the equivalent simple lever being 1:20. All parts where friction could be prejudicial were provided with knife-edges. The design of the machine is obvious from the figure, in which A represents the specimen of ice to be tested, held by the collars at Band C. D is an equipoise, to balance the weights of the levers and of the vessel H, through which the power is applied by means of shot. F is a hand-wheel fixed to the screw G, by means of which, as the specimen extends, the under collar C may be lowered, so that the position of the upper collar B and of the two levers may remain the same. An index at H shows when the parts of the instrument are in the relative position required, and by its motion enables a rough estimate to be formed of the extension of the specimen. The temperature was rendered more equable by enclosing the appa- ratus in two wooden boxes, KL and MN. A delicate thermometer, graduated to tenths of a degree centigrade, and reading from —6° C. to +6° C., was attached to the central 492 Dr. J. F. Main. (KV = I ULL Y | - IB. SSX. CRG SN) S NN Im as | SZ Za CW x —— = = alfa I. Y MHZ) Wi is Y | G2 L : Tm i * . VMMM@Z]ZXZTVPXYWUi_ Vda eee wooden pillar, which supports the upper lever. The greatest variations of temperature inside the inner box were given in Experi- ment 3, and, on the days mentioned in the record of Experiment 2, by two thermometers, maximum and minimum, attached to the roof of the inner box. The centres of the bulbs were about 73 cm. from the roof. ate On the Viscosity of Ice. 493 The ice specimen was formed by freezing water in a cylindrical iron mould, with a conical expansion at one end. To obtain ice as free as possible from included air, 1 in some cases (but not in all) boiled the water and then froze it. Afterwards it was melted in the mould, boiled, and then allowed again to freeze. In this way nearly all the air was expelled, only a small core of minute bubbles up the axis of the cylinder remaining. In Experiment No. 1, however, these precautions were not taken, and thus the cylinder of ice had linear bubbles of air, radiating in horizontal straight lines from the axis of the cylinder. These were due to expulsion of the air from the water, in which it was dissolved, as the latter froze in concentric cylindrical shells from outside inwards. After the ice cylinder had been freed from contact with the mould, by bathing the latter in warm water, it was passed through the conical iron collar (C in figure) which the conical expansion of the ice fitted, and which had been screwed to the upper part of a wooden frame. The other collar (B) was then attached to a moveable plate in the wooden frame, which was capable of motion vertically and horizontally, and, by adjusting screws, both the frame and the collar B could be made accurately horizontal. By asmall plummet. the ice cylinder was made to hang vertically, by placing small pieces of cork between it and the edge of the opening in B. Water was then run into B, and, when frozen, a cylinder of ice was obtained, held above and below in two conical collars. By the above-mentioned adjust- ments it was ensured that the cylinder of ice was perpendicular to the surfaces of the two collars B and C. As the weight of the two iron collars was over 4°5 kilos., much care was needed to prevent fracture of the ice, which, unless handled tenderly, broke with the least jar, on being inserted in the machine. The lower surface of the upper, and the upper surface of the lower collar had been planed true, and brass rings fitted on them. These rings were also made plane surfaces. They extended so far from the ice specimen that it was possible to use callipers between the surfaces of these brass rings, without interference with the larger ends of the conical collars. The ring on B was provided with four small holes, 90° apart on the circumference, and by means of a small plummet the points on the ring of C (which ring was graduated roughly) that were vertically under the four points on the ring above, were deter- mined. By noting these graduations it was rendered certain that the measures would always be taken between the same points in the upper and under rings. Since the ice specimen was inserted in the apparatus with its axis vertical, the lines measured between the points thus determined on the two rings, were, in each case, parallel to the axis of the cylinder. The callipers used measured to the one- fiftieth of a millimetre. A494 Dr. J. F. Main. I used the rings because I have not been able to devise means, as yet, for so firmly fixing objects in the ice that there would be no danger of displacement by their own weight, or during the measure- ment by callipers. The results obtained are therefore affected by errors, if any, which may be due to action at the collars, such as slipping through, owing to distortion of the conical enlargements. This effect is but slight at temperatures below the freezing point; though near and above freezing point the collars, when the ice is under tensile stress, will not hold it, but, in the course of a few hours, by distortion of its conical enlargements, it slips through them. At lower temperatures, to act as'a check on the measurements taken between the rings on the collars, and to determine if any appreciable effect was due at those temperatures to slipping through the collars, I gummed two pieces of paper on the ice specimen near the top and bottom. On each of these a small pencil mark was made, and hy means of a rule, [ got a measure of the distance between the points. By repeating this measure on a subsequent day, a rough value was obtained of the extension between the marked points. The distance could be estimated to about the quarter of a millimetre, and showed that, with low temperatures, nearly all the extension observed was due to the stretching of the piece, and not to a shearing action of the ice in the collars. In the tabular results of three exper:ments which follow, the first column gives the date; the second the hour, reckoned from Berne mean midnight, at which the observations were taken; the third column gives the temperature in degrees centigrade, read by an attached Kew-verified thermometer, graduated to tenths of a degree; the fourth column gives in millimetres the mean of the distances of the points on the upper from those on the lower ring. These dis- _ tances, four in number, were taken at opposite extremities of two perpendicular diameters of the rings. The next column furnishes the mean extension in millimetres in the interval that has elapsed since the last observation. The sixth column gives, in hundredths of a millimetre, the hourly mean extension deduced from the preceding column, and the interval which has elapsed between the two observa- tions. The two next columns give, in kilogrammes per square centimetre, the mean and the maximum stress respectively. By the rapid evaporation from the ice cylinder, even at low temperatures, the amount of this stress increased from day to day, with the same load at the further end of the compound lever. Since the evaporation was different at different parts of the ice cylinder, owing probably to variations in texture, and still more to the effect of the proximity of the collars to the ice above and below, which protected the ice near them from evaporating so quickly as in other parts, the diameter of the cylinder at different heights varied. Thus the mean stress, as a On the Viscosity of Ice. 495 deduced from three measurements of the diameter, at the top, in the middle, and at the bottom, differed from the maximum stress, as deduced from the total load and the least area of section. The last column but one in Experiment No. 1 gives the minimum temperature the preceding night, measured, not in the box, but by a thermometer freely exposed out of doors. Since the ice specimen was enclosed in the double box its temperature did not sink as low as those given in this column. The numbers here are only to be taken as sig- nifying that the night was or was not specially cold. Unfortunately in this experiment no maximum and minimum temperature observa- tions were taken. In LHxperiments 2 and 3 the maximum and minimum temperatures were observed, when recorded, by a maximum and a minimum thermometer suspended in the box, and their deter- minations furnished “‘ the range of temperature.” Experiment 1. Mean original length of specimen not subjected to tension, measured at 9.15 on Feb. 7th.......... = 233°48 mm. Mean length with load of 5°5 kilos................. = 23422 ,, Giving a sudden increase in length of.............. O74 ,, Measured just afterwards it had become............ = 23458 _,, After 13 hours (at night) under same load......... == 2p 98a). Giving a,mean hourly extension. of ................: O05) = After 2 hours (temp. —5°0°) the length became..... = 230°04 ~,, Cavin am hourly extension of ......2..c00--+0++-- G02), The load on the specimen was then increased to 12°5 kilos., and the mean length became 235°12 mm. VOL. XLII. 2N Dr. J. F. Main, AY6 “ToyemMouLoyT} porjonye oy Aq pBor oq P[NOO YOIyA yseaoy 943 “GQ .CQ— MoTeq eanqerodutey v sojouep g “loyJRoroy pue otoyT y 4) UMOP MOTOS 0% 9TqQIssod LOSUOT OU SBM 4I OOF *SyIVULOY —_—_—_—_—____eeeeeeee—ee—ee—e——x——xr 0-8T—- > ee Sci ‘qU.sTu Sutpooerd Stoop Jo yno einyeredure4 UINLUATUL TAT "a.1] OUT} U90 erenbs tod ‘soyty UL Sso.148 UINUIXV FAL “OLJOUATZUIO erenbs rod *sO]Iy Ut ssoi9s uve . 4 IN ATANoY URETT WOSDOMOHSOOCOSOSOOON AND AOPMONMOOnRN 100 "OLZOURTT [LUN ®@ JO syjporpuny | Ul woIsuezxo UL UOISUN4xXe "UUL TT = SF.S8S — SP.FPS = Wouttoeds Jo uoisuoyxe [eyoT, 68-0 IL-0 L0-0 Lc .0 61-0 v1.0 06.0 66-1 80-T OS. T II-T €4-0 9¢-0 69-0 *SOLJOULIT [LUA UvoTL CV TVS &9- SFG 6G: SVG CV: SPS GL. GVS SP - che 66- GPG SL. 6vZ G6-1VZ &4- OFS G9. 6&2 GT. 8% PO. LEZ 18-9826 GL. 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STZ | oo TL |"y9Z2 “qe, “L881 ‘OagOUNIGUSD | s nommueo | OMOUMITTEUE Se ee orenbs be aie ®B JO “SOTJOUIT[IUL | *sSotjourtyyIM | ‘opvasryuos "SYAVULO YT ee 41 xed ROTH | od «Syst SY}potpuny | UL UoIsue}xo | UL oOUYsIP | sooddop Ur |unoyT| ‘ayeq J a UL sso.14s ee UT | ur uorst0yxo UBOTT UBOTT oarnyerod wd J, UINUIXV IT mee ATINoOY UBT, ‘@ quow110d xm On the Viscosity of Ice. 499 The specimen broke by a jar due to the falling of a weight on the floor of the room. On February 27th the three observations were taken, with different loads on the specimen, directly after one another. With a load of 55 kilos. (the weight of the lower collar) there was an immediate extension of 0°22 mm.; and when the load was increased to 12°5 kilos. the extension at once increased by 0°04 mm. The three experiments, of which the results are given above, show that ice subjected to tension stretches continuously by amounts which evidently depend on the temperature and on the tensile stress. When the stress is great, as in No. l, and the temperature not very low, there are appreciable extensions, as on February 15th, amounting to as much as 1 per cent. of the whole length per day. When the tem- perature is lower, and the stress is less, the extension is less, but still such as can be measured. So continuous and definite is the extension, that it can even be measured from hour to hour, as seen in HExperi- ment No. 1, when for February 15th and 16th easily measurable extensions were obtained for intervals of two and three hours. The quantities actually measured were generally both notably greater and less than the mean, since, owing probably to inequalities in the dis- tribution of the stress and to variations of texture in the ice, due to internal strains produced in freezing, one side of the specimen would sometimes stretch 50 per cent. more than the other. Hence differential motions resulted in the ice. These motions and exten- sions took place at temperatures which preclude all possibility of melting and regelation, expecially in Experiments 1 and 2. In Ex- periment No. 1, it was found that in three days, from February 13th to February 16th, the distance between two marks on pieces of paper cummed on the ice increased from 200 mm. to 203 mm., giving an elongation of $ per cent. per day. This method fails at tempera- tures very near the freezing point, owing to the danger that by thawing the pieces of paper may slip, but is free from this risk at lower temperatures. It is in any case very rough, and is only useful as a check on the other measures, since there is no question here of slipping through the collars. How close the correspond- ence in the results obtained is may be seen by observing that in Experiment 1 there was an extension in nine days of 11 mm. in the case of a cylinder of ice, which at the beginning of that time was 235 mm. long, and this gives an elongation of just about 5 per cent. per day, the same as resulted from the three days’ observa- tion with the marked bits of paper. The experiments are to be regarded rather as proving the exist- ence of continuous extension under tensile stress than as deter- mining its amount. The quantities observed are functions of the stress, of the time between two observations, and of the time integral 500 Dr. J. F. Main. during that interval of the temperature. Owing to the rapid evapo- ration from ice, even at low temperatures, when the surface is never liquefied, at such an elevation (6100 feet above sea level) as St. Moritz, in the Engadine, where the observations were carried on, the Specimen is subjected to a continually increasing stress. This varia- tion in the stress can no doubt be diminished by clothing the speci- men in flannel. The change of temperature I expect to diminish by filling the interval between the two surrounding wooden boxes with some non-conducting material. In this way I have good hope that, on resuming the experiments next winter at St. Moritz, I may be able’ to determine more nearly the law of extension. That there is such extension, and that it goes on continuously with all stresses above 1 kilo. per square centimetre, and at all temperatures between —6° C. and freezing point, is shown by the above experiments. When ice is in a condition such that pressure with the point of a needle will cause a set of radiating fractures to pass from the point of contact in all directions, it stretches as certainly, although not by so great an amount, as when it will permit the passage through it of the same needle without showing the least trace of flaw or scar. In the discussions, for the most part @ priori, on the extensibility of ice, sufficient importance has not usually been assigned to the neces- sity of distinguishing between the effect of even a small blow or jar and that of a much greater force applied gradually and steadily during a long interval. A bar of ice may bear a stress of 4 and 5 kilos. per square centimetre if the load is steady, which would fracture at once with a much smaller sudden stress, especially if not uniformly distributed. In the first experiment we notice a total extension in nine days of ll mm. In No. 2 there is an extension of 1°8 mm. in five days, and in No. 3 of 1:7 mm. in three days. If we assume for the moment am extension proportional to the time, we should thus get a mean daily extension in the three experiments of 1°2 mm., 0°36 mm., and 0°56 mm. respectively. To account for the discrepancy we remark that the stress in No, 1 is much greater than in 2 or 3, and the temperature not so very low during the day, although low at night. The effect of increased stress is well shown in Experiment No. 2, on February 23rd and 24th, where, on increasing the stress from 2°28 to 3°65 kilos., the extension in a day rises at once from 0°08 to 0°69 mm. In No. 2, for three out of the five days, the temperatures were below —6° C., whilst in No. 3 there was a low stress but comparatively high tem- peratures. ; In Experiment No. 2 the large numbers obtained at first probably arose from the fact that in preparing the specimen its conical ex- pansion had frozen to the collar C. When the water run into the collar B began to freeze it expanded, and thrust the ice upwards. The Air of Sewers. d01 As it was frozen to the collar C, and therefore unable to expand upwards, since both collars were fixed to a frame, the cylindrical part of the ice bulged outwards, as in the usual case of a long column under compression. When the specimen was subsequently exposed to tension, the effect of the latter was to straighten it, so that in a few days it no longer bulged out. The straightening of the central line of the ice cylinder thus gave rise to greater extensions than were due simply to the extension of a straight bar of ice with an equal dis- tance in all azimuths between the rings. “The Air of Sewers.” By Professor THOMAS CARNELLEY, D.Sc., and J. 8. Hatpang, M.A., M.B., University College, Dundee. Communicated by Sir H. Roscoz, F.R.S. Re- ceived May 21.—Read June 16, 1887. Owing to the complaints which had been made of bad smells in the House of Commons, a Select Committee was appointed in the spring of 1886 to inquire into the ventilation of the House. In consequence of the experience we had gained in the course of an extensive exami- nation of the air of houses and schools in Dundee (see ‘ Phil. Trans..,’ vol. 178 (1887), B, p. 61), we were instructed by the Committee to make a series of analyses of the air in the sewers under the Houses of Parliament, and to report thereon (see ‘Second Report of the Committee,’ Appendix). Since then we have examined the air in a considerable number of sewers in Dundee. Our object was, in the first place, to obtain a general idea of the amount of some of the more important impurities present in sewer air. But we have also endeavoured to throw some light on their sources, and on the conditions affecting their dissemination. With this view we found it desirable to supplement our observations in the sewers by a certain number of laboratory experiments. In spite of the great amount of discussion which has taken place in connexion with real and supposed danger from sewer air, there have hitherto been but few analyses published of the air of sewers of modern construction. The first and most complete set of analyses was that made by Dr. Letheby in 1857-58 (‘Report to the City of London Commissioners of Sewers,’ 1858). He examined the air of thirteen sewers in the City of London. The following are the means of his analyses :— VOL. XLII. 20 502 Messrs. Carnelley and Haldane. 100 grains of air deprived | Vols ot! itananeeds of water and carbonic acid | | Oxygen, | Nitrogen,| carbonic and # k gave after oxidation. mmonia. per cent.| per cent. | acid per |sulphuretted 10,000. | hydrogen. . Carbonic Ww acid. ater. 19-506 | 79-962 |. 53-2 traces. “Rather |1°247 grains.|1‘126 grains. abundant.” | Unfortunately no information is given as to the condition and means of ventilation of these sewers. In 1867 Dr. Miller,* in an investigation on the action of charcoal air filters, made a number of analysesin two London sewers. The first series was made in a clean and well-ventilated sewer, and the second in a sewer described as “ tide-locked and ill-ventilated.” In the first series (eighteen analyses) he found on an average 10°6 vols., and in the second (six analyses) 30°7 vols. of carbonic acid per 10,000 vols. of air. In neither series could sulphuretted hydrogen be detected, and in both series the ventilation was by means of open gratings. In 1877 Beetz}+ in Munich found 31°4 vols. of carbonic acid, and 2-2 vols. of ammonia per 10,000 as an average of five analyses. As regards the micro-organisms present in sewer air the only analyses hitherto published are those of Miquel.t He says, “The atmosphere of sewers, always saturated with moisture and constantly in contact with water more or less filthy and loaded with putrefying substances, is heavily charged with bacteria. Judging from a series of experiments made in the sewer of the Rue de Riveli in the neigh- _ bourhood of the point at which this sewer joins the large collector of the Boulevard Sébastopol, there are present in the air circulating in this gallery 800 to 900 bacteria per cubic metre’’§ (= 0°8 to 0°9 per litre). He also states that the air of the sewer contains an almost constant number of bacteria, and that in summer the air of the Rue de Rivoli may exceed in impurity by five or six times that of the sewer, while in winter the air of the sewer may be five or six times more impure. No details are furnished as to the condition and means of ventilation of the sewer, nor as to the number of analyses on which these conclusions are based. * ‘Chemical News,’ March 13th, 1868. + Quoted by Erismann in Pettenkofer and Ziemssen’s ‘Handbuch der Hygiene,’ vol. 2, p. 197. f~ ‘Les Organismes Vivants de l’ Atmosphére,’ 1883, p. 273. § These numbers refer to the bacteria capable of developing in a solution of Liebig’s extract of 1°024 specific gravity placed in an incubator at 30°—35°. The Air of Sewers. 508 - Miflet (‘ Biedemann’s Centralbl.,’ 1880, p. 227) states that air taken from above a sink was rich in micro-organisms. In detailing our own observations it may be as well, in ne first place, to give some account of the sewers in which they were made. The main sewer of Westminster Palace,* in which our first observa- tions were made, ran along underneath the open couris in the centre of the building from the neighbourhood of the Victoria Tower to that of the Clock Tower, a short way beyond which it joined the main low-level metropolitan sewer. Along its course it varied irregularly in height from 43 to 104 feet. It was ventilated by suction from the large furnace at the foot of the Clock Tower, and was cut off by a penstock from the metropolitan sewer. The air drawn into the shaft of the furnace almost all came from openings near the Clock Tower end of the sewer. In the rest of the sewer there were no open gratings, andthe draught was feeble. On opening the trap-door of a man-hole near the Victoria Tower there was an upward rush of air and condensed vapour, in spite of the very powerful suction at the other end of the sewer. The sewer was flushed daily. It was clean, | and the flow of sewage was pretty rapid. The water frequently accumulated in the sewer during rain owing to rise of the level of the water in the metropolitan sewer. Our analyses were made when the water was escaping freely. The second set of analyses at Westminster was made after the ventilation of the sewer had been altered by carrying an additional shaft to the furnace and placing inlet gratings in suitable positions. By this means the draught along the sewer from the neighbourhood of the Victoria Tower was much increased. We owe the facilities which were afforded us for examining the air in the Dundee sewers to the courtesy of Mr. Mackison, Burgh Engi- neer. We met with a variety of conditions in these sewers. They are all ventilated by open gratings placed in the roadway at distances’ of about 50 yards apart, and also by the open drain grids placed along each side of the road at distances of about 40 yards. The flow of sewage was in almost every case pretty rapid at the time when our analyses were made. The sewers in Commercial Street, Overgate, and Nethergate are egg-shaped; that in Murraygate is a large circu- lar sewer. Those in Reform Street and Dock Street had originally been large, old, flat-bottomed stone sewers, but had been partially altered by the substitution of a bottom similar to that of an egg- shaped sewer. The Dock Street sewer is alternately filled and emptied by the tide, as is also the sewer in Commercial Street, opposite Hx- change Street. 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WON | 04 woo | -100 SOA "STO A "STO A ‘OUIT} 4B Iv OPIsjNO FO ssaoxe UT [R40], 508 Messrs. Carnelley and Haldane. given in the table of results (pp. 504—507). It will be seen that the sewers which we examined were all of considerable size, large enough to be entered without great difficulty. Our data, therefore, do not apply to small sewers and drains. In each sewer examined we estimated simultaneously the amounts of carbonic acid, “organic matter,’ and micro-organisms, as in the case of our observations referred to above on the air of houses and schools. Analyses of outside air in the immediate vicinity of the sewers examined were made at as nearly as possible the same time. In order to avoid as far as possible contaminations due to our own presence we kept to leeward of the apparatus employed in collecting the samples. The methods employed were that of Pettenkofer for carbonic acid, Carnelley and Mackie’s modification of the permanganate process for organic matter,* and Hesse’s method for micro-organisms. The results obtained are given in the preceding table. For the purpose of giving a general idea of the relative impurity of sewer air we have taken the averages of analyses A and B of sewer air and placed them alongside of the averages for outside air at the same time, and for various classes of houses and schools, as determined by us in the winter of 1885-86 and detailed in the paper mentioned above. | The above table shows (1) that the air of the sewers was much better than one might have expected; (2) that the carbonic acid was about twice, and the organic matter rather over three times as great as in outside air at the same time, whereas the number of micro- organisms was less; (3) that in reference to the quantity of the three constitue nts named, the air of the sewers was in a very much better condition than that of naturally ventilated schools, and that with the notable exception of organic matter it had likewise the advantage of mechanically ventilated schools; (4) that the sewer air contained a much smaller number of micro-organisms than any class of house. . The carbonic acid was rather greater than in the air of houses of four rooms and upwards, but less than in two- and one-roomed houses. As ‘regards organic matter, however, the sewer air was only slightly better than the air of one-roomed houses, and much worse than that of the other classes of house.{ These facts are brought out more clearly in the following table, in which the average quantity in excess of outside air of each constituent in sewer air is taken as unity. * © Roy. Soc. Proc.,’ vol. 41, p. 238. t+ ‘Mittheilungen aus dem k. Gesundheitsamte,’ vol. 2, p. 182. { The data for all the classes of houses refer to sleeping-rooms when occupied during the night, The Air of Sewers. 509 Micro- organisms.* Carbonic | Organic acid. matter. 0 PNET ESE Senco eee hi 1 iH OME TOGMCH as ...! 3°9 6°6 — 9°2 Mite errno draught..:...<.4-..... 6:0 5°5 —14°3 A similar result was obtained from our observations at West- minster, where we made six observations before, and six after the improvements in the ventilation referred to above. Carbonic Organic Micro- _acid. matter. organisms. | Average before improvement........ ce 11:0 7 | Average after improvement....... 6°2 2°7 10°3 | The only other source for the micro-organisms of sewer air is con- The same arguments which have just been applied against the sewer itself being a source of micro- organisms may be urged in favour of their origin from outside air. tamination from the outside air. 512 Messrs. Carnelley and Haldane. — The mere fact that the average number found in the sewer air (89) was less than that in outside air at the same time (159) is itself a strong argument in favour of the origin of most of the micro- organisms from outside air. If the air takes up micro-organisms in its course along a sewer, we should expect the number to increase rather than diminish during its passage, whereas the opposite is the case, doubtless from gradual settling of solid particles. This settling is perhaps even greater than appears from our analyses, as it was not. practicable to take specimens of outside air at the gratings in the centre of the roadway with the traffic proceeding as usual. At these points the contamination of the air by solid particles of organic origin would of course be at its maximum. Tt will be noticed that in the analyses made at Westminster the numbers obtained for the sewer air close to the Clock Tower were always larger than those for outside air (see Table, pp. 504—505). Not much stress can, however, be laid on this fact, as a great part of the air passing along the sewer at this point came from a side drain near the Clock Power leading from a point where the outside air was much more likely to be contaminated by dust from traffic than in the central court, where the outside air analyses were made. The outside air de- terminations at Westminster apply strictly to the sewer determinations near the Victoria Tower and kitchen, as these determinations were made just at the opening of the inlet grating ventilating this part of the sewer. It will be seen that the micro-organisms inside the sewer decreased in proportion to the decrease in those present in the outside air. Another argument in favour of the origin of most of the micro- organisms from outside may be derived from the fact that the average proportion of moulds to bacteria was nearly the same in the sewer air and corresponding outside air, 1 to 9 in the former and 1 to 8 in the latter. Were the micro-organisms in sewer air mostly de- rived from a different source than outside air we should expect the - proportion to be different. Thus in two cases referred to below, in which the micro-organisms were evidently derived from splashing in the sewer, among 128 micro-organisms there were no moulds. In the micro-organisms present in the air of naturally ventilated schools and one-roomed houses, the average proportion present was found to be 1: 132 and 1 : 49 respectively, as against 1 : 2°5 in the corresponding outside air (‘ Phil. Trans.’ 1887; B, p. 99). A final argument is that so far as a naked- -eye examination of the colonies allowed one to judge, the micro-organisms in the sewer air we examined were, with perhaps one exception, similar to those in outside air. The exception referred to was in the case of some very rapidly liquefying colonies which occurred in several samples of sewer air, collected at points where there was more or less splashing. The Air of: Sewers. 513 These possibly came from the sewer itself, as we have not observed ‘in outside air or in buildings any colonies which liquefied the jelly as rapidly or so extensively, ; The conclusion thus arrived at as to the source of most of the micro-organisms present in sewer air is, perhaps, at first sight, contrary to what one might have expected, It is in agreement with the fact that the state of cleanliness or filthiness of a sewer seems to have no perceptible effect on the number of micro-organ- . isms present in the air of the sewer, Thus two observations on two different days and at two different points of the dirtiest sewer we examined, gave only 25 and 12 micro-organisms respectively, as compared with an average of 43; and 9 in other and cleaner sewers on the same days. Our conclusion is also in agreement with what is known as to the distribution of bacteria in air. Nageli (‘Die Niederen Pilze,’ pp. 109, 111) has shown that liquids or damp substances do not, with ordinary air currents, give off micro- organisms to the surrounding air. He even found that air drawn through gravel which had been saturated with filth and then dried, gave off no micro-organisms (p. 169). Miquel (‘Comptes Rendus,’ vol. 91, p. 64) states that the vapour of water rising from the soil, from rivers, or from masses in full putrefaction, is free from germs; that the gases evolved from decaying substances, and the air passed over putrid meat are free from germs, provided that the putrefying sub- stance is as moist as soil taken 0°3 metre from the surface. The experiments of Professor Frankland (‘ Roy. Soc. Proc.,’ vol. 25, 1877, p- 542) also point to the improbability of micro-organisms being disseminated in air by such agitation of a liquid as that produced by the flow of sewage along a sewer. On the other hand, it is well known that the micro-organisms already present in air are always tending to sink to the ground. On this fact Hesse’s method depends. Hence air in its passage along a sewer will presumably tend to gradually deposit its micro-organisms, especially if the air-current is slow. In order further to elucidate this point, and in particular with regard to the drain pipes leading into houses, we made some experi- ments with an artificial drain-pipe. Through the side of a wooden box, AB, there was passed the end of a piece of glass tubing, CD, 5 feet long and 12 inches in diameter, and open at both ends. In the opposite side of the box there was a hole, by means of which the air inside the box could be comunected with the entrance to a Hesse’s tube, and the micro-organisms thus determined. Through the roof of the box there passed a chimney, in which a draught was maintained by means of a small flame, F, kept burning at the bottom. This, of course, caused a corresponding draught through the long tube and into the box. A constant stream of water was kept running along the d14 Messrs. Carnelley and Haldane. bottom of the experimental sewer, the sides of which were also moistened before each experiment. By estimating the micro-organisms in the air at the mouth of the tube and in the box, the difference caused by passage of the air along the tube could be determined. The rate of the current of air through the long tube was in all the experiments 5 feet in six seconds. The determinations were made simultaneously, after the draught had been established for a short time. Air of laboratory (before | Air of box (after passing Quantity of | passing through tube). through tube). No. of air aspirated experiment. through Hesse’s tube.| Total micro- | yroujqs. Total micro- Moulin organisms. organisms. es % litre 200 100 2. s litre 205 141 De D Iitres. sai... 4 0 3 I A. BD WGYeS os 9 0 2 1 Shes 5 litres .... 1 Thom if 0 6.. % Litre ispeie 344 47 189 42 ins + litre..... 221 67 17 73 Average = 141 23 80 23 In Nos. 1, 2, 6, and 7 the air was rendered dusty by shaking mats in the room. Nos. 3, 4, and 5 were made with the air of the labora- tory in its ordinary condition. The Air of Sewers. 515 It will be seen that the micro-organisms were diminished by nearly one half in passing along the tube. This confirms our conclusions as to the settling of micro-organisms insewer gas. The micro-organisms would settle out of a drain-pipe especially with great rapidity. Judging from the rate at which they settle in a Hesse’s tube, air standing in, or passing along, a 4-inch drain-pipe would become entirely free of micro-organisms within three or four minutes. Hence it seems improbable that micro-organisms can penetrate into a house from a sewer unless with a pretty rapid current towards the house. It will be seen from the table that the moulds are more numerous in proportion to bacteria after the air has passed through the tube than before. This is due to the fact, first observed by Hesse, that moulds fall through air less rapidly than bacteria. We should expect to find a similar alteration in the proportion in badly ventilated sewers, but our observations in such sewers were not sufficiently numerous to enable us to say whether this is actually the case. Although, as has been seen, most of the micro-organisms present in the air of the sewers we examined seem to have come from the outside air, yet in some cases we had distinct evidence of the dissemination of micro-organisms from sewage itself. In Dundee a few, and at Westminster a large proportion of the drains were found to enter the sewers through the roof. This gave rise to a considerable amount of splashing, the effect of which on the dissemination of micro-organisms in the air it seemed of great importance to investi- gate. The following observations in the sewers bear upon this point. An analysis was made within about 2 feet of a shower of water pro- ceeding from the roof of the Dock Street sewer, the draught being very slight. The number of micro-organisms present was 103 (all bacteria). An analysis made shortly afterwards a few feet to wind- ward of the shower of water gave only twelve micro-organisms. During one of the analyses made at Westminster, a sudden and very violent shower of sewage occurred about 10 feet to windward of the tripod carrying the Hesse’s tube. In this case the number found was 25 (all bacteria), whereas an analysis made at the same point a few minutes later, after the dripping had ceased, gave only eight micro-organisms. One of the analyses in the Murraygate sewer was made within about 30 feet of the point where the Hill Town sewer enters the Murraygate sewer, there being a draught of about 2 feet per second from this point to the spot where the analysis was made. The Hill Town sewer has a steep incline, and the water contained in it rushes down with great force, forming a sort of water-fall, the roar of which sounded most impressive as it echoed along the sewer. The analysis only gave three micro-organisms per litre.* * The low number thus obtained was possibly owing to the fact that the waste 516 Messrs. Carnelley and Haldane. From the first two observations it appears that micro-organisms are undoubtedly disseminated in sewer air by splashing ; but whether they are carried far in the air cannot be decided from the above experiments. The point is one of great practical importance, as the micro-organisms in question are those on which most suspicion of properties injurious to health naturally falls. Hence we thought it desirable to make some laboratory experiments with a view to elucidating the matter. In connexion with the effects of splashing we also investigated the effects of the bursting of bubbles. Professor Frankland (‘ Roy. Soe, Proc.,’ vol. 25, p. 542) has already made experiments on this point hy means of lithia solutions. He found that lithia was disseminated in the air and carried to a considerable distance, when a solution of lithia was made to effervesce. Hence the presumption is that micro- organisms might be disseminated in a similar way. Our experiments were made with the artificial drain-pipe arrange- ment described above (pp. 518—514). Control determinations of the air in the box were first made after the draught had been established some little time. A putrefying solution was then poured from a height into a vessel placed at about 6 inches below the end of the glass tube, so as to imitate the splashing in a sewer; or effervescence was brought about in the same solution, placed at the mouth of the long glass tube by adding sodium carbonate and hydrochloric acid, or by blowing small and numerous jets of air through the putrid fluid by means of a fine rose from an ordinary garden hose pipe. water from a dye works was discharged into this sewer, accompanied by a distinct smell of chlorine at the time of our experiment. These conditions possibly exerted a disinfecting action. O17 "yOu -110dxo YJJ, UI SouO deILT 94 OYIT Suteq ouO Ay So gee een} N ‘kep 7¢ uo splnout er qnoqy 011, 00e qnoqy I *OL4IT I ecovneoertoeoeesoo eh aeerenenooee @ monhvg | aay) “Lep WIE UO splnou OOT Jnoqy 0991, 009 FROG T ‘OIUT T prynd ysnoarqy ave Butmotq Ag |e tse s%e ; arn *obtes ‘Avp U49gG uo spynour OOL qnogy °099IC. Oss qnoqy I eX} ii eo oe ee i eoeooceree ee oe oe oe On out eeeseovee ‘P : ‘SROLOTUNU 004 10M 2 —VltoOVq oY} Inq ‘poJUN0D otoM SplNoU OOg S kep aE 047 UG ‘poeqyunod oq of sno1zowWNU | “VYs1oY & 004 o1om LOZ YOM 1097v ‘Aep puoves UO oLg ynoqy T ‘aI T eB WOT, Lo}yvut prqnd surmod Aq |°***ss** +e gOS > ae : ae *98B0 LOY410 (é P 0 2'0 006 BT SO ee gee ng ee ee eI bel ag © UI Sp[NOUL OU O10M OLOTT, “plow otaxopyooupAyy | | > eadf JO MOTJOV Suryoazuistp oy} 07 onp ATqQIs | 4 ‘ping SS -sod svM osvo sIq} UI dOUeDSeALOZe Sulanp | | piaynd 03 oye8u0g.1¥v0 wNIpos pue poureyqo saoquinu ey} JO ssouMOT OY, le Z 0 0'D 006 poe omopqooupAy jo uoyrppe Ag [ores ste eT "T sold ‘or ‘suryserds |oap ‘duryserds Sutin qnoyyt MA “g aA ‘poqeatdse are ‘DUIISOATOO LO “quoted xa ARAM tsb jo AqyWueny suryseids Ssuronpoad jo opoy, jo ‘ON ‘odid-ureap ysnory4 Sutssed 104ze KOq Jo aIy VOL. XLII, “SOT}IUOI}X9 ILOY 4e spvoy JInaz yoRyq oynuru surtveg pur ‘suo[ YOur UN ynoqge ‘sproryy oyT-r1ey eqeorjep dn SUTMOIYY ‘SOLMOTOD SULOV]LOFUL OFIT[M [NJTIJNvIG IGIVT O1OM XIS YOIYM FO ‘splMou gE oO e1oyy Avp YIG UQ “poeztinod oq OF snoseUNU 00} o1om AoYY YoryM ateqye ‘Avp pug uC 08g Juoqy ) "OLUIT T ‘on ‘suryserds |‘o2p ‘suryseds SUL qnoyyl AA ‘poqeaidse are jo Lyrquenyy “SHAVUOT ‘royyem prynd ey 9AOGe SOTPOUI G JHoge puR IoAO ATJOoITP pozo][OO ATW Messrs. Carnelley and Haldane. "qq s10q “AT Sontag ‘dIUIOSIALI JO Io ‘quotuttedxe suryseyds Sutonpoad jo spoyl jo ‘ON The Air of Sewers. O19 These results are very decided, and confirm and extend for micro- organisms the results obtained by Professor Frankland for lithia solutions. They show conclusively not only that micro-organisms are disseminated in sewer air by splashing, but that those having this origin may be carried to a considerable distance along a sewer or drain-pipe. Calculating from these experiments, air vitiated as above described, and to a similar extent, would still contain about 400 micro-organisms per litre after travelling about 60 yards, in a sewer 5 feet high, and with a draught of about 1 foot per second. It is therefore of the greatest importance that sewers and drains should be so arranged as to avoid splashing as much as possible. The Physiological Effects of Unorganised Organic Matter in Sewer Air. In view of the fact that ordinary sewer air, in the absence of splash- ing, turned out to be to all appearances comparatively innocent as regards its micro-organisms, and assuming that it has an injurious effect on health, we directed further attention to the unorganised organic matter present in it. Of organic compounds most likely to produce some of the bad effects ascribed to sewer air, volatile ptomaines* at once suggest themselves, on account of the intensely poisonous properties possessed by various known ptomaines.t We therefore endeavoured to ascertain whether sewer air contains any poisonous volatile bases. or this purpose air was drawn continuously for thirty-four days from the sewer side, below the trap, of an earthen pipe, which acted as the drain from the College water-closets and urinals. This air was bubbled continuously through very dilute sul- phuric acid, in order that any basic substance which the air contained might be retained. The solution thus obtained was subsequently neutralised exactly with ammonia, and evaporated to dryness on a water-bath. The residue was dissolved and injected subcutaneously into rabbits, but produced no effect whatever, even in doses of a gram of the dry substance. Evidently if there was any poisonous substance in the air, it was not contained in the residue injected. Unfortunately this experiment is not conclusive, on account of the instability of many of the organic bases in question. If poisonous organic substances had been present in serious quanti- ties in the air of the sewers we examined, we should presumably have ourselves felt some effects from them, as we were sometimes in the sewers for several hours, more or less continuously. We could never observe any bad effects, however, from our stay, although we were previously quite unaccustomed to entering sewers. * Ptomaines are basic nitrogenous compounds formed by the decomposition of animal or vegetable matter. é + Cf. Brieger, ‘ Ueber Ptomaine,’ 1885-86. Ape 520 Messrs. Carnelley and Haldane. Haperiments on the Efficiency of Water-traps. ‘The means commonly employed for preventing the escape of sewer air into houses is the ordinary water-trap. Since the experiments of Nageli (‘ Die Niederen Pilze,’ p. 109) it has been known that these traps, when acting properly, absolutely prevent the passage of micro- organisms. But it is evident that they cannot altogether prevent the passage of volatile constituents of sewer air, and we thought it worth while to make a few experiments on this point. We were not aware that the matter had already been experimentally investigated by Fergus (‘The Sewage Question,’ 1874), who employed methods simi- lar to those used by us. As, however, the test substances used by us were nearly all different from those employed by Fergus, it may be well to give the results of our experiments. A leaden (J-shaped trap, ABC, 22 inches in diameter, and with a seal, a b, of 3 inches in depth, was closed at each end, A and C, with a sheet of india-rubber stretched tightly over the mouth and fixed with wire, each sheet | being perforated by a hole in the middle. The trap was then filled with water, and a glass stopper placed in the aperture H, while the neck of a flask D, containing the substance under investigation, was fixed through the india-rubber sheet at A. The whole was then left at rest, and observations made from time to time by removing the stopper and ascertaining whether the smell of the substance in D could be detected at E. In other cases a tightly fitting inverted test-tube, containing litmus or other test-paper, was inserted at EH, in place of the glass stopper, and observations made as to when the test-paper was first distinctly affected. The results obtained are given in the following table :— 521 "deaj wepvoy UT ‘dei uspvoy uy ‘der o1mmtoyyaee UT oe ‘pastprxo to prot q dn uoye}y = Ajqeqoad o@Fy : deay uopeoy, uy S “pBoy LoF UoTJOVaL op) qysts @ ATWO eaves pu ‘yuoUT = -T1od xo oy} 1047 Ayptut A194 19048 AA > << “Oy x “OI © 1 SOT ECE = . dery toprol uy “SyIVULO Ay ‘sep OT 10978 U9Ad P9qdeJop oY JOU p[NoD ‘sInoy GE—Qe ‘sinoy ¢e—% ‘sKep OT toqFe WIAD poyoyap oq Jou p[nog ‘sep p oqy ‘smmoy % L1—g ‘smoy $¢—-¥G ‘smnoy g—*te *Sunoy &g—te "04 CQ Woy ssed 04 anodva Aq poamboer owt, 66 OLL “ 086 “ 06 “ 0&6 “ 096 ** 028 ‘“* O16 “ 086 '0'0 O68 “dear ut TOA 66 g "SOYOUL “your (73 (<9 ‘a9 (a3 6 "SOTOUL "[Bos jo yy4do -& I § € 6 € € € a ‘soded snwyIy ong ‘soded snuryiy poy Fee ee ee eee ona ‘Tjows pu toded 0984908 pat ieee LOCUS ‘Tous pues toded oqvaqia toATig 66 eeee ~e@ woe co oe ee oe bao O89 ce Bnet ees TOU "MOTJOO}Op IOF posn 4s, * (st0143) prow o1to;qooapé Fy "sss -oyvmOqred ULNTMOULULYy sefeeee sea See ee er ONG ‘aprydins tintmomuy V+eeesees oomnf quour prayng ce cee *-oprydsoyd wuNTITeA soe ee ee ee ee “**"quIut FO [IO Die eS aes OS) Ath JO [lO 2 ee LEIS MOE TONG) _—_——. “C YSPLH UL voueysque 922 The Air of Sewers. Fergus found that free ammonia came through a somewhat similar trap in 15 minutes, carbonic acid in 14 hour, sulphuretted hydrogen in 3 to 4 hours, &c. He also refers to similar experiments in which a ventilating pipe was placed between the substance experimented on and the trap, in which the result was much the same, except that the time occupied in penetrating the trap was longer. Though it is thus the case that water-traps after some time allow a certain amount of various volatile substances to pass through, yet it is hardly conceivable that the small amount thus allowed to pass can have any appreciable influence on health. We do not propose to enter here on any general discussion of the effects of the inhalation of sewer air on health. The results of the foregoing investigations are clearly such as to make us much more suspicious as to supposed evidence of the bad effects of ordinary sewer air, such as that of the sewers examined by us. At any rate it is evident that, “‘ sewer gas,” unless it has been vitiated by splashing, has a much less deadly composition than is often supposed. It must be remembered, however, that the matter cannot in the present state of our knowledge be settled by analyses alone, though analyses may serve as a guide in the investigation. INDEX to VOL. XLII. ABERCROMBY (R.) on the relation between tropical and extra-tropical cyclones, 138. Abney (W. de W.), total eclipse of the sun observed at the Caroline Islands on May 6, 1883, 482. transmission of sunlight through the earth’s atmosphere, 170. Abrus precatorius (jequirity), the pro- teids of the seeds of (Martin), 331. Adams (J. C.), supplementary note on the values of the Napierian logarithms of 2, 3, 5, 7, and 10, and of the modulus of common logarithms, 22. Air, further experiments on the distri- bution of micro-organisms in, (by Hesse’s method) (Frankland and Hart), 267. --— of sewers, the (Carnelley and Haldane), 394, 501. studies of some new micro-or- ganisms obtained from (Frankland and Frankland), 150. Alcohol, a study of the thermal proper- fe of methyl (Ramsay and Young), 37. Clausius’s formula for the change of state from liquid to gas applied to Messrs. Ramsay and Young’s observa- tions on (Fitzgerald), 216. Alloys, note on the electrodeposition of, and on the electromotive forces of metals in cyanide solutions (Thomp- son), 387. Alternate current dynamo, note on the theory of the (Hopkinson), 167. Alumina, on the crimson line of phos- phorescent (Crookes), 25. Anatomy of Asiatic cholera, note on the, as exemplified in cases occurring in Italy in 1886 (Sherrington), 474. Andrews (T.), electrochemical effects on magnetising iron, 459. Anschiitz (R.) and P. N. Evans, contri- butions to our knowledge of anti- mony pentachloride, 379. Anthrax, note on protection in (Wool- dridge), 312. Antimony pentachloride, contributions to our knowledge of (Anschiitz and Hyans), 379. Aromatic bodies, preliminary commu- nication on the action of certain (Brunton and Cash), 240. Atmosphere, transmission of sunlight through the earth’s (Abney), 170. Atmospheric oxidation, note on the development of voltaic electricity by (Wright and Thompson), 212. Auricular appendices, note on the func- tions of the sinuses of Valsalva and; with some remarks on the mechanism of the heart and pulse (Collier) 469. Baird (Major A. W.) admitted, 189. Bakerian lecture (Thomson), 343. Balanoglossus larva from the Bahamas, preliminary note on a (Weldon), 146. [. | note on the above (Weldon), 473. Barometric pressure, some anomalies in the winds of Northern India and their relation to the distribution of (Hill), 35. Bee, second note on the geometrical con- struction of the cell of the honey (Hennessy), 176. Beevor (C. EH.) and V. Horsley, a fur- ther minute analysis, by electric sti- mulation, of the so-called motor region of the cortex cerebri in the monkey (Macacus sinicus), 483. Birds, on the morphology of (Parker), 52. the development of the branchial arterial arches in, with special refer- ence to the origin of the subclavians and carotids (Mackay), 429. Bismuth, contributions to the metal- lurgy of (Matthey), 89. Blechnum occidentale (i.).and Osmunda regalis (L.), on the structure of the mucilage cells of (Ito and Gardiner), 308. Blood serum, note on a new constituent of (Wooldridge), 230. Blood-vessels of Mustelus antarcticus, note to a paper on the (‘ Phil. Trans.,’ 1886) (Parker), 437. Boileau, John ‘Theophilus, notice, 1. Bonney (T. G.), note on the geological bearing of Mr. Davison’s paper, 328. obituary o24 Bonney (T. G.), note on the microscopic stucture of rock specimens from three peaks in the Caucasus, 318. Bottomley (J. T.) on radiation from dull and bright surfaces, 433. measure, 357. Bourne (A. G.), the reputed suicide of scorpions, 17. Boys (C. V.), preliminary note on the ‘radio-micrometer, a new instru- ment for measuring the most feeble radiation, 189. Branchial arterial arches in birds, the development of the, with special reference to the origin of the sub- clavians and carotids (Mackay), 429. Brunton (T. L.) and J. T. Cash, action of caffein and theine upon voluntary muscle, 238. contributions to our know- ledge of the connexion between che- mical constitution and physiological action; preliminary communication on the action of certain aromatic bodies, 240. Buchanan (John Young) elected, 352. admitted, 352. Burch (G. J.) on a perspective micro- scope, 49. Caffein and theine, action of, upon volun- tary muscle (Brunton and Cash), 238. Calamites, on the true fructification of the carboniferous (Williamson), 389. Caldwell (W. H.), the embryology of monotremata and marsupialia. Part I, TT Candidates for election, 145. list of selected, 316. Carboniferous. calamites, on the true fructification of the (Williamson), 389. Carnelley (T.) and J. S. Haldane, the air of sewers, 394, 501. Cash (John Theodore) elected, 352. admitted, 352. and T. L. Brunton, action of caffen and tkeine upon voluntary muscle, 238. contributions to our know- ledge of the connexion between che- mical constitution and physiological action; preliminary communication on the actien of certain aromatic bodies, 240. Caucasus, note on the microscopic struc- ture of rock specimens from three peaks in the (Bonney), 318. Cell of the honey bee, second note on the geometrical construction of the (Hen- nessy), 176. on thermal wags ee in absolute - wn INDEX. Ceratochelys sthenwrus, preliminary note on the fossil remains of a chelonian reptile, from Lord Howe’s Island, Australia (Huxley), 232. Cerebral cortex, a record of experiments: upon the functions of the (Horsley and Schafer), 111. Chemical constitution and physiological action, contributions to our knowledge of the connexion between (Brunton and Cash), 240. Chlorophyll, contributions to the che- mistry of, No. II (Schunck), 184. Cholera, note on the anatomy of Asiatic, as exemplified in cases occurring in Italy in 1886 (Sherrington), 474. Chree (C.), conduction of heat in liquids, 300. Clausius’s formula for the change of state from liquid to gas applied to Messrs. Ramsay and Young’s observa- tions on alcohol (Fitzgerald), 216. Coal-dust explosion, a (Galloway), 174. Coal-measures, on the organisation of the fossil plants of the; Heterangium Tilieoides (Will.) and Kaloxylon Hookeri (Williamson), 8 Collier (M.), note on the functions of the sinuses of Valsalva and auricular appendices, with some remarks on the mechanism of the heart and pulse 469. Colour-relation between certain ound lepidopterous pupe and the surfaces which immediately surround them, an inquiry into the cause and extent of a special (Poulton), 94. Computation of the harmonic compo- nents of a series representing a pheno- menon recurring in daily and yearly periods, on the (Strachey), 61. Conduction of heat in liquids (Chree), 300. Continuity of the liquid and gaseous. states of matter, ee note on the (Ramsay and Young), 3 Cortex cerebri in the monkey (M acacus sinicus), a further minute analysis by electric stimulation of the so-called motor region of the (Beevor and Horsley), 483. Cotopaxi, on the occurrence of silver in volcanic ash from the eruption of, of July 22nd and 23rd, 1885 (Mallet), 1 Crookes (W.) on the supposed ‘new force’ of M. J. Thore, 345. on radiant matter spectroscopy ; examination of the residual glow, ab Eile on the crimson line of phosphos rescent alumina, 25. - Croonian lecture (Seeley), 337. INDEX. Cubics, on the diameters of plane, (Walker), 334, 483. Current sheets, on ellipsoidal (Lamb), 196. Cyclones. on the relation between ‘tropical and extra-tropical (Aber- cromby), 138. Darwin (G. H.) on figures of equili- brium of rotating masses of. fluid, 309. note on Mr. Davison’s paper on the straining of the earth’s crust in cooling, 483. Dasyuride, on the homologies and suc- cession of the teeth in the, with an attempt to trace the history of the evolution of mammalian teeth in general (Thomas), 310. Davison (C.) on the distribution of strain in the earth’s crust resulting from secular cooling, with special reference to the growth of continents and the formation of mountain- chains, 325. [ | note on the geological bearing of Mr. Davison’s paper (Bonney), 328. [- | note on Mr. Davison’s paper (Dar- win), 483. Definite integrals, on certain (Russell), 477. Dispersion equivalents. stone), 401. Dissociation of some gases by the electric discharge, on the—Bakerian lecture (Thomson), 343. Douglass (Sir James Nicholas) elected, - 352. admitted, 352. Dowdeswell (G. F.) on rabies, 355. Dynamical principles, some applications of, to physical phenomena. Part il (‘Lhomson), 297. Dynamo, note on the theory of the alternate current, (Hopkinson), 167. Part I (Glad- Earth’s crust, on the distribution of strain in the, resulting from secular cooling, with special reference to the - growth of continents and the forma- tion of mountain-chains (Davison), 325. [ ] note on the geological bearing of Mr. Davison’s paper (Bonney), 328. note on Mr. Davison’s paper on the straining of the, in cooling (Darwin), 483. Echidna Ramsayi (Ow.), on fossil re- mains of. Part Il (Owen), 390. Eclipse of August 29, 1886, report of the observations of the total si made at Carriacou (Perry), 316. O20 Eclipse, total, of the sun observed at the Caroline Islands on May 6, 1883 (Abney), 482. of Aug. 22, 1886, on the total solar, (preliminary account) (Schuster), 180. Elasticities, the velocity of sound in metals and a comparison of their moduli of torsional and longitudinal (Tomlinson), 362. Election of Fellows, 16, 352. Electric time-constant of a circular disk,’on the principal (Lamb), 289. discharge, on the dissociation of some gases by the—Bakerian lecture (Thomson}, 343. stimulation, a further minute analysis by, of the so-called motor region of the cortex cerebri in the monkey (Macacus sinicus) (Beevor and Horsley), 483. Electrical organ of Torpedo marmorata, the electromotive properties of the (Gotch), 357. Electricity, note on the development of voltaic, by atmospheric oxidation (Wright and Thompson), 212. experiments on the discharge of, through gases ; second paper (Schus- ter), 371. on the rate at which electri- city leaks through liquids which are: bad conductors of (Thomson and Newall), 410. Electrochemical effects on, magnetising iron (Andrews), 459. Electrodeposition of alloys, note on the, and on the electromotive forces of metals in cyanide solutions (Thomp- son), 387. Electromotive forces of metals in cyanide solutions, note on the electrodeposi- tion of alloys and on the (Thompson), 387. properties, the, of the electrical. organ of Torpedo marmorata (Gotch),, 307. Elements, a geometrical interpretation _ of the first two periods of chemical, following hydrogen, showing the re- lations of the fourteen elements to each other and to hydrogen by means. of aright line and cubic curve with one asymptote (Haughton), 482. Elliot (Sir Walter), obituary notice, vill. Ellipsoidal current sheets, on (Lamb),, 196. Embryology of marsupialia and mono- tremata. Part I (Caldwell), 177. Equilibrium, on figures of, of rotating: masses of fluid (Darwin), 359. o26 Etiology of scarlet fever, the, (Klein), 158. Evans (P. N.) and R. Anschiitz, contri- butions to our knowledge of antimony pentachloride, 379. Evaporation and dissociation. Part V. A study of the thermal properties of methyl alcohol (Ramsay and Young), 37. Ewart (J. C.) on rigor mortis in fish and its relation to putrefaction, 438. Ewing (James Alfred), elected, 352. admitted, 352. and W. Low, on the magnetisation of iron in strong fields, 200. Explosion, a coal-dust (Galloway), 174. Explosive wave, on the induction of the, and an altered gaseous condition in an explosive gaseous mixture by a vibratory movement (Wright), 472. Fellows elected, 16, 352. Figures of equilibrium of rotating masses of fluid, on (Darwin), 359. Fish, on rigor mortis in, and its relation to putrefaction (Ewart), 438. Fitzgerald (G. F.), on the thermo- dynamic properties of substances whose intrinsic equation is a linear function of the pressure and tempera- ture, 50. Clausius’s formula for the change of state from liquid to gas applied to Messrs. Ramsay and Young’s obser- vations on alcohol, 216. Fluid, on figures of equilibrium of rota- ting masses of, (Darwin), 359. Forbes (George), elected, 352. admitted, 352. ~—— a thermal telephone transmitter, 141. Frankland (G. C.) and P. F. Frankland, studies of some new micro-organisms obtained from air, 150. Frankland (P. F.) and T. G. Hart, fur- ther experiments on the distribution of micro-organisms in air (by Hesse’s method), 267. Galloway (W.), a coal-dust explosion, 174. Gardiner (W.) and T. Ito on the structure of the mucilage cells of Blechnum occidentale (L.) and Os- munda regalis (L.), 353. Gaseous states of matter, preliminary note on the continuity of the liquid and (Ramsay and Young), 3. Gases, experiments on the discharge of electricity through; second paper (Schuster), 371. on the dissociation of some, by INDEX. the electric discharge—Bakerian lec- ture (Thomson), 343. Gasterolichenes, on, a new type of the group Lichenes (Massee), 370. . Gilbert (J. H.) and Sir J. B. Lawes on the present position of the question of the sources of the nitrogen of vegetation, with some new results, and prelimin- ary notice of new lines of investigation, 483. Gladstone (J. H.), dispersion equiva- lents. Part I, 401. Gotch (F.), the electromotive properties of the electrical organ of Torpedo marmorata, 357. Gowers (William Richard) elected, 352. admitted, 352. Griffiths (A. B.) on the nephridia and ‘liver’ of Patella vulgata, 392. Haldane (J. 8.) and T. Carnelley, the air of sewers, 394, 501. Halliburton (W. D.) on muscle plasma, - 400. Halsbury (Lord) elected, 16. admitted, 35. Hamilton’s numbers, on (Sylvester and Hammond), 470. Hammond (J.) and J. J. Sylvester on Hamilton’s numbers, 470. Hardman (EK. T.), note on Professor Hull’s paper, 308. Harmonic components, on the computa- tion of the, of a series representing a phenomenon recurring in daily and yearly periods (Strachey), 61. Hart (T. G.) and P. F. Frankland, further experiments on the distribu- tion of micro-organisms in air (by Hesse’s method), 267. Haughton (Rev. S.), a geometrical inter- pretation of the first two periods of chemical elements following hydrogen, showing the relations of the fourteen elements to each other and to hydro- gen by means of a right line and cubic curve with one real asymptote, 482. Heart and pulse, note on the functions of the sinuses of Valsalva and auri- cular appendices with some remarks on the mechanism of the (Collier), 469. Heat in liquids, conduction of (Chree), 300. - Hennessy (H.), problems in mechanism regarding trains of pulleys and drums of least weight for a given velocity ratio, 134. second note on the geometrical construction of the cell of the honey bee,. 176. INDEX. Heterangium Tilieoides (Will.) and Kaloxylon Hooker: (Williamson), 8. Hill (S. A.),. some anomalies in the winds of Northern India, and their relation to the distribution of baro- metric pressure, 35. Hinde’s (Dr. G. J.) paper ‘on beds of sponge-remains in the lower and upper greensand of the South of England’ (‘ Phil. Trans.,’ 1885, p. 403), note on (Hull), 304. Hopkinson (J.), note on induction coils or ‘transformers,’ 164. note on the theory of the alternate current dynamo, 167. Horsley (V.) and C. E. Beevor, a further minute analysis, by electric stimulation, of the so-called motor - region of the cortex cerebri in the _ monkey (Macacus sinicus), 483. and HE. A. Schifer, a record of ex- periments upon the functions of the cerebral cortex, 111. Hulke (J. W.), supplementary note on _ Polacanthus Foxii, describing the _ dorsal and some parts of the endo- skeleton imperfectly known in 1881, 16. Hull (E.), note on Dr. G. J. Hinde’s paper ‘on beds of sponge-remains in the lower and upper greensand of the South of England’ (‘Phil. Trans.,’ 1885), 304. {——] note on the above (Hardman), 308. Huxiey (T. H.), preliminary note on the fossil remains of a chelonian reptile, Ceratochelys. sthenurus, from Lord . Howe’s Island, Australia, 232. Hydrogen, a geometrical interpretation of the first two periods of chemical elements following, showing the rela- . tions of the fourteen elements to each other and to hydrogen by means of a . right line and cubic curve with one real asymptote (Haughton), 482. Ice, note on some experiments on the . viscosity of (Main), 329, 491. Iceland spar, on the effect of polish on the reflexion of light from the surface of (Spurge), 242. India, some anomalies in the winds of Northern, and their relation to the _ distribution of barometric pressure (Hill), 35. ; Indnetion coils or ‘ transformers,’ note - on (Hopkinson), 164. Integrals, on certain definite. No. 15 (Russell), 477. Iron, electrochemical effects on magnet- ising (Andrews), 459. i 27 Iron, on the magnetisation of, in strong - fields (Ewing and Low), 200. Ito (TI.) and W. Gardiner on the structure of the mucilage cells of Blechnum occidentale (L.) and Os- munda regalis (L.), 353. (Jequirity), the proteids of the seeds of Abrus precatorius (Martin), 331. Johnson (G. 8.) on kreatinins. I. On the kreatinin of urine, as distinguished from that obtained from flesh-kreatin. IT. On the kreatinins derived from the dehydration of urinary kreatin, 365. Kaloxylon Hookeri, Heterangium Tili- g@oides (Will.) and (Williamson), 8. Kempe (A. B.), note to a memoir on the theory of mathematical form (‘ Phil. Trans.’, 1886), 193. Kennedy (Alexander B. W.) elected, 352. admitted, 352. King (George) elected, 352. Kirk (Sir John) elected, 352. admitted, 352. Klein (E), the etiology of scarlet fever, 158. Kreatinins, on. I. On the kreatinin of urine as distinguished from that obtained from flesh-kreatin. II. On the kreatinins derived from the de- hydration of urimary kreatin (John- son), 365. Lamb (H.) on ellipsoidal current sheets, 196. on the principal electric time- constant of a circular disk, 289. Lawes (Sir J. B.) and J. H. Gilbert on the present position of the question of the sources of the nitrogen of vegetation, with some new results, and preliminary notice of new lines of investigation, 483. Leguminosee, the tubercular swellings on the roots of the (Ward), 331. Lepidodendron Harcourtii and L. fuli- ginosum (Will.), note on (William- son), 6. Lepidopterous pupz and the surfaces which surround them, an inquiry into the cause and extent of a special colour-relation between certain ex- posed (Poulton), 94. Lichenes, on Gasterolichenes, a new type of the group (Massee), 370. Light, on the effect of polish on the re- flexion of, from the surface of Iceland spar (Spurge), 242. Liquid and gaseous states of matter, 528 | INDEX. preliminary note on the continuity of the (Ramsay and Young), 3. L:.juids, conduction of heat in (Chree), 300. which are bad conductors of electricity, on the rate at which elec- tricity leaks through (Thomson and Newall), 410. ‘Liver’ of Patella vulgata, on the nephridia and (Griffiths), 392. Liversidge (Archibald) admitted, 343. Lockyer (J. N.), further discussion of the sun-spot observations made at South Kensington, 37. Lodge (Oliver Joseph) elected, 352. Logarithms of 2, 3, 5, 7, and 10, supple- mentary note on the values of the Napierian, and of the modulus of common logarithms (Adams), 22. Low (W.) and J. A. Ewing on the magnetisation of iron in strong fields, 230. Macacus sinicus, a further minute analysis by electric stimulation of the so-called motor region of the cortex cerebri in the monkey (Beevor and Horsley), 483. Mackay (J. Y.), the development of the branchial arterial arches in birds, with special reference to the origin of the subclavians and carotids, 429. Magnetic induction (Tomlinson), 224. Magnetisation of iron in strong fields, on the (Ewing and Low), 200. Magnetising iron, electrochemical effects on (Andrews), 459. Main (J. F.), note on some experiments on the viscosity of ice, 329, 491. Mallet (J. W.) on the occurrence of silver in voleanic ash from the erup- tion of Cotopaxi of July 22nd and 23rd, 1885, 1. Marsupialia and monotremata, the em- bryology of. Part I (Caldwell), 177. Martin (8.), the proteids of the seeds of Abrus precatorius (jequirity), 331. Massee (G.) on Gasterolichenes, a new type of the group Lichenes, 370. Mathematical form, note to a memoir on the theory of (‘ Phil: Trans.,’ 1886) (Kempe), 193. Matthey (K.), contributions to the metallurgy of bismuth, 89. Mechanism, problems in, regarding trains of pulleys and drums of least weight for a given velocity ratio (Hennessy), 134. Meiolania platyceps (Ow.), on parts of the skeleton of (Owen), 297. Metallurgy of bismuth, contributions to the (Matthey), 89. ‘Metals, velocity of sound in, and a comé parison of their moduli of torsional and longitudinal elasticities as deter-. mined by statical and kinetical me- thods (Tomlinson), 362. £ in cyanide solutions, notéion the | electrodeposition of alloys and.on the © electromotive forces of (Thompson), © 387. Micro-organisms in air, further experi- ments on the distribution of, (by Hesse’s method) (Frankland and Hart), 267. - obtained from air, studies of some new (Frankland and Frankland), 150. Microscope, on a: perspective (Burch), 49. Milne (John) elected, 352. . Monkey (Macacus sinicus), a further minute analysis by electric stimula- tion of the so-called motor region of the cortex cerebri in the (Beevor and Horsley), 483. , Monotremata and marsupialia, the em- bryology of. Part I (Caldwell), 177. Morphology of birds, on the (Parker), 52 ~ Motor region of the cortex cerebri, a further minute analysis of the so- called, in the monkey (Macacus sinicus) (Beevor and Horsley}, 483. Mucilage cells of Blechnum occidentale (L.) and Osmunda regalis (L.), on the structure of the (Ito and Gardiner), 353. Muscle, action of caffein and theine upon voluntary (Brunton and Cash), 238. Muscle plasma, on (Halliburton), 400. Mustelus antarcticus, note to a paper on the blood-vessels of (‘ Phil Trans.,” 1886) (Parker), 437. Nephridia and ‘liver’ of Patella vul- gata, on the (Griffiths), 392. ‘New force’ of M. J. Thore, on the supposed (Crookes), 345. Newall (H. F.) and J. J. Thomson on the rate at which electricity leaks through liquids which are bad con- ductors of electricity, 410. Nitrogen of vegetation, on the present position of the question of the sources of the, with some new results, and preliminary notice of new lines of in- vestigation (Lawes and Gilbert), 483. Obituary notices of fellows deceased :— Boileau, John Theophilus, i. A Elliot, Sir Walter, viii. ‘ie Thomson, Allen, xi. “ Whitworth, Sir Joseph, ix. Ornithorhynchus paradoxus, descrip- - tion of a newly-excluded young of the (Owen), 391. Osmunda regalis (L.) and Blechnum occidentale (L.), on the structure of - the riucilage cells of (Ito and Gardi- ner), 353. Owen (Sir R.) on parts of the skeleton of Meiolania platyceps (Ow.), 297. on fossil remains of Echidna ' Ramsayi (Ow.), 390. description of a newly-excluded young of the Ornithorhynchus para- doxus (Ow.), 391. Parieasaurus bombidens (Owen), on, and the significance of its affinities to amphibians, reptiles, and mammals (Seeley), 337. Parker (T. J.), note to a paper on the bload-vessels of Vustelus antarcticus (‘ Phil. Trans.,’ 1886), 437. Parker (W. K.) on the morphology of . birds, 52. Patella wulgata, on the nephridia and ‘liver’ of (Griffiths), 392. Perry (S. J.), report of the observations of the total solar eclipse of August 29, 1886, made at Carriacou, 316. Perspective microscope, on a (Burch), 49. Phosphonium chloride, on (Skinner), ' 283. Phosphorescent alumina, on the crimson - line of (Crookes), 25. Physical phenomena, some applications of dynamical principles to. Part II (Thomson), 297. properties of matter, the influence of stress and strain on the. Part III. Magnetic induction (Tomlinson), 224. properties of matter, the influence of stress and strain on the. Part I. Elasticity (continued) (Tomlinson), 362. Physiological action, contributions to our knowledge of the connexion between chemical constitution and (Brunton and Cash), 240. Pickard-Cambridge (Rev. Octavius) . elected, 352. Plane cubics, on the diameters of - (Walker), 334, 483. Plants of the coal-measures, on the or- ganisation of the fossil, Heterangium - Liligoides (Will.) and Kaloxylon Hookeri (Williamson), 8. Plasma, on muscle (Halliburton), 400. Pleura, on the force with which the two layers of the healthy, cohere (West), 482. olacanthus Foxti, supplementary note . on (Hulke), 16. INDEX. 529 Polish, on the effect of, on the reflexion of light from the surface of Iceland spar (Spurge), 242. Poulton (EK. B.), an inquiry into the cause and extent of a special colour- relation between certain exposed lepi- dopterous pups and the surfaces which immediately surround them, 94. Preece (W. H.) on the limiting distance of speech by telephone, 152. Presents, lists of, 10, 31, 47, 59, 86, 109, 131, 142, 163, 1172) 182, »210, 240, 302, 314, 336, 342, 350, 483. Proteids, the, of the seeds of Abrus precatorius (jequirity), (Martin), 331. Protorosaurus Speneri (yon Meyer), on (Seeley), 86. Pulse, note on the functions of the sinuses of Valsalva and auricular appendices with some remarks on the mechanism of the heart and (Collier), 469. Pupe, an inquiry into the cause and extent of a special colour-relation between certain exposed lepidopte- rous, and the surfaces which imme- diately surround them .(Poulton), 94. Putrefaction, on rigor mortis in fish and its relation to (Ewart), 438. Rabies, on (Dowdeswell), 355. Radiant matter spectroscopy, on; ex- amination of the residual glow (Crookes), 111. Radiation, preliminary note on the ‘radio-micrometer’ a new instru- ment for measuring the most feeble (Boys), 189. on thermal, in absolute measure (Bottomley), 357. from dull and bright surfaces, on (Bottomley), 433. ‘ Radio-micrometer,’ preliminary note on the, a new instrument for measur- ing the most feeble radiation (Boys), 189. Ramsay (W.) andS. Young, preliminary note on the continuity of the liquid and gaseous states of matter, 3.. evaporation and dissociation. Part V. A study of the thermal pro- perties of methyl alcohol, 37. Reflexion of light from the surface of Iceland spar, on the effect of polish on the (Spurge), 242. Residual glow, on radiant matter spectro- scopy ; examination of the (Crookes), EBYs . Rigor mortis in fish, on, and its relation to putrefaction (Ewart), 438. 530 INDEX. Rock specimens from three peaks in the Caucasus, note on the microscopic structure of (Bonney), 318. Roots of the Leguminosex, the tuber- cular swellings on the (Ward), 331. of Vicia faba, on the tubercular swellings on the (Ward), 356. Rosebery (Earl of) admitted, 352. Rotating masses of fluid, on figures of equilibrium of (Darwin), 359. Russell (H. C.) admitted, 352. Russell (W. H. L.) on certain definite integrals, No. 15, 477. Scarlet fever, the etiology of (Klein), 158. Schafer (HE. A.) and V. Horsley, a re- cord of experiments upon the func- tions of the cerebral cortex, 111. Schunck (E.), contributions to the che- mistry of chlorophyll. No. II, 184. Schuster (A.) on the total solar eclipse of August 29, 1886 (preliminary account), 180. experiments on the discharge of - electricity through gases (second - paper), 371. Scorpions, the reputed suicide of (Bourne), 17. Scott (A.) on the composition of water by volume, 396. Seeds of Abrus precatorius (jequirity), the proteids of the (Martin), 331. Seeley (H. G.) on Protorosaurus Speneri (von Meyer), 86. on Parieasaurus bombidens (Owen), and the significance of its affinities to amphibians, reptiles, and mammals— Croonian lecture, 337. Series representing a phenomenon recur- ring in daily and yearly periods, on the computation of the harmonic com- ponents of a (Strachey), 61. Serum, note on a new constituent of blood (Wooldridge), 230. Sewers, the air of (Carnelley and Hal- dane), 394, 501. Sherrington (C.8.), note on the anatomy of Asiatic cholera as exemplified in cases occurring in Italy in 1886, 474, Silver in volcanic ash from the eruption of Cotopaxi of July 22nd and 23rd, 1885, on the occurrence of (Mallet), 1. Sinuses of Valsalva, note on the func- tions of the, and auricular appendices, with some remarks on the mechanism of the heart and pulse (Collier), 469. Skinner (8.) on phosphonium chloride, 283. Snelus (George James) elected, 352: admitted, 352. - Sound, the velocity of, in metals, and a comparison of their moduli of tor- sional and longitudinal elasticities as determined by statical and kinetical methods (Tomlinson), 362. Spectroscopy, on radiant matter, ex- amination of the residual glow (Crookes), 111. Speech by telephone, on the limiting distance of (Preece), 152. Sponge-remains in the lower and upper greensand of the south of England, note on Dr. G. J. Hinde’s paper on beds of (Hull), 304. Spurge (C.) on the effect of polish on the reflexion of light from the surface of Iceland spar, 242. Strachey (R.) on the computation of the harmonic components of a series representing a phenomenon recurring. in daily and yearly periods, 61. . Strain in the earth’s crust resulting from secular cooling, on the distribu- tion of, with special reference to the growth of continents and the forma- tion of mountain chains (Davison), 325. [ | note on the geological bearing of Mr. Davison’s paper (Bonney), 328. [. | note on Mr. Davison’s paper (Darwin), 483. Stress and strain, the influence of, on the physical properties of matter. Part III. Magnetic induction (Tom- linson), 224. the influence of, on the physical properties of matter. Part I. Elasticity (continued). The velocity of sound in metals, and a comparison of their moduli of torsional and lon- gitudinal elasticities as determined by statical and kinetical methods (Tomlinson), 362. Sun, total eclipse of the, observed at the Caroline Islands on May 6, 1883 (Abney), 482. Sunlight, transmission of, through the earth’s atmosphere (Abney), 170. Sun-spot observations made at South Kensington, further discussion of the, (Lockyer), 37. Sylvester (J. J.) and J. Hammond on Hamilton’s numbers, 470. = Teeth in the Dasyuride, on the homolo- gies and succession of the, with an attempt to trace the history of the evolution of mammalian teeth in general (Thomas), 310. Telephone, on the limiting distance of speech by (Preece), 152. transmitter, a thermal (Forbes), 141. aa ee ee ee ee _—- Theine, action of caffein and, upon voluntary muscle (Brunton and Cash), 238. Thermal telephone transmitter, a, (Forbes), 141. radiation in absolute measure, on (Bottomley), 357. properties of methyl alcohol, a study of the (Ramsay and Young), 37 Thermodynamic properties of sub- stances whose intrinsic equation is a linear function of the pressure and temperature, on the (Fitzgerald), 50. Thomas (O.) on the homologies and succession of the teeth in the Dasy- uride, with an attempt to trace the history of the evolution of mamma- lian teeth in general, 310. Thompson (C.) and C. R. A. Wright, note on the development of voltaic electricity by atmospheric oxidation, 212. Thompson (S. P.), note on the electro- deposition of alloysand on the electro- motive forces of metals in cyanide solutions, 387. Thomson (Allen), obituary notice, x1. Thomson (J. J.), some applications of dynamical principles to physical phe- nomena. Part Ii, 297. on the dissociation of some gases by the electric discharge—Bakerian lecture, 343. and H. F. Newall, on the rate at which electricity leaks through liquids which are bad conductors of elec- tricity, 410. Thomson (Sir W.) on the waves produced by a single impulse in water of any depth, or in a dispersive medium, 80. on the formation of coreless vor- tices by the motion of a solid through an inviscid incompressible fluid, 83. Thore (M. J.), on the supposed ‘new force’ of (Crookes), 345. Time-constant of a circular disk, on the principal electric (Lamb), 289. Tomlinson (H.), the influeuce of stress and strain on the physical properties of matter. Part Il. Elasticity (con- tinued). The velocity of sound in metals, and a comparison of their moduli of torsional and longitudinal elasticities as determined by statical and kinetical methods, 362. the influence of stress and strain on the physical properties of matter. Part I1I. Magnetic induction, 224. Torpedo marmorata, the electromotive properties of the electrical organ of (Gotch), 357, INDEX. Tae ‘Transformers,’ note on induction coils- or (Hopkinson), 16+. Tubercular swellings, the, on the roots. of the Leguminosez (Ward), 331. on the roots of Vicia faba, on the (Ward), 356. Urine, on kreatinins. I. On the krea- tinin of, as distinguished from that. obtained from fiesh-kreatin. II. On the kreatins derived from the dehy- dration of urinary kreatin (Johnson), 365. Valsalva, note on the functions of the sinuses of, and auricular appendices, with some remarks on the mechanism of the heart and pulse (Collier), 469. Vegetation, on the present position of the question of the sources of the nitrogen of, with some new results, and preliminary notice of new lines. of investigation (Lawes and Gilbert), 483. Vicia faba, on the tubercular swellings. on the roots of (Ward), 356. Viscosity of ice, note on some experi- ments on the (Main), 329, 491. Volcanic ash from the eruption of Coto- puxi of July 22nd and 23rd, 1885, on the occurrence of silver in (Mallet), 1. Voltaic electricity, note on the develop- ment of, by atmospheric oxidation (Wright and Thompson), 212. Vortices, on the formation of coreless,. by the motion of a solid through an inviscid incompressible fluid (Thom- son), 83. Walker (J. J.) on the diameters of plane cubics, 334, 483. Walsingham (Thomas, Lord) elected, 352. admitted, 352. Ward (H. M.) on the tubercular swell- ings on the roots of Vicia faba, 356. the tubercular swellings on the -roots of the Leguminoseex, 331. Water, on the composition of, by volume (Scott), 396. Waves produced by a single impulse in water of any depth, on the, or in a dispersive medium (Thomson), 80. Weldon (W. F. R.), preliminary note on a Balanoglossus larva from the Bahamas, 146. note on the above, 473. West (S.) on the force with which the two layers of the healthy pleura co- here, 482. Whitaker (William) elected, 352. bor INDEX. Whitworth (Sir Joseph), obituary no- tice, 1x. Williamson (W. C.), note on Lepidoden- dron Harcourtii and L. JAILS ET, (Will.), 6. on the organisation of the fossil plants of the coal-measures; Heter- angium Tilieoides (Will.) and Kalo- xylon Hookeri, 8. -on the true fructification of the carboniferous calamites, 389. Winds of Northern India, some ano- malies in the, and their relation to the distribution of barometric pres- sure (Hill), 35. Wooldridge (L. C.), note on a new con- stituent of blood serum, 230. Wooldridge (L. C.), note on protection in anthrax, 312. Wright (C. R. A.) and 0. Thompson, note on the development of voltaic electricity by atmospheric oxidation, 212. Wright (L. T.) on the induction of the explosive wave and an altered gaseous condition in an explosive gaseous mix- ture by a vibratory movement, 472. Young (S.) and W. Ramsay, prelimi- nary note on the continuity of the liquid and gaseous states of matter, 3. evaporation and dissociation. Part V. A study of the thermal properties of methyl alcohol, 37. ERRATA. Page 86, lines 1 and 5, for Proterosaurus, read Protorosaurus. Page 86, line 28, for Proterosauria, read Protorosauria. Pages 429, 431, 432, in head lines, for Brachial, read Branchial. END OF FORTY-SECOND VOLUME. HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE. OBITUARY NOTICES OF FELLOWS DECEASED. JOHN THEOPHILUS BoulLEeAv, son of Thomas Boileau, at one time a well-known solicitor in Calcutta, and afterwards Chief Magistrate of that city, was born there May 26th, 1805. His maternal grandfather, Colonel Jessup, was an American Loyalist who suffered severely for the support he gave to the King’s cause. The Boileau family are of Huguenot descent. In 1819, when still much under fifteen, he was nominated a cadet to Addiscombe by Charles Marjoribanks of the E.I. Direction. Among his contemporaries were several whose names are more or less prominent in modern Indian history, such as Henry Lawrence and his © elder brother George, James Abbott (of Khiva), with his brother Sir Frederick. Boileau, aged 153, passed out of Addiscombe for the Engineers, December 19, 1820, and after a short practical training on the Trigonometrical Survey, and at Chatham under Colonel Charles Pasley, went to India, arriving at Fort William September 22nd, 1822. The Corps of Bengal Engineers was in those days a very small one, its cadre including only thirty-six officers, and, if they entered it with a somewhat imperfect training, the manifold and incessant work into which the young officers were speedily plunged afforded them at least a very varied experience. During the first twelve years of Boileau’s service we find him engaged as executive engineer in the construc- tion of fortifications, roads, barracks, an important church and gaol, a considerable suspension bridge, and what not, and (among other duties when stationed at Agra) on measures for the conservation of the splendid buildings left there by the Mogul dynasty, including the Taj itself. He married in 1829, and made a voyage to Hurope with his family in 1837. Whilst at home he published a work which has had extensive use among surveyors, and of which he had already issued a lithographed edition in India (1836). The London publication is entitled: ‘‘ A new and complete Set of Traverse Tables, showing the Differences of Latitude and the Departures to Every Minute of the Quadrant, and to Five Places of Decimals; together with a Table of the Lengths of each Degree of Latitude and corresponding Degree of Longitude from the Equator to the Poles; with other Tables nseful to the Surveyor and Civil Engineer. By Captain J. T. Boileau, H.EH.1.C. Bengal Engineers. London: W. H. Allen & Co., Leaden- hall Street, 1839.”* * A note in General Boileau’s handwriting, dated 12th November, 1880, says : “These Traverse Tables were prepared to facilitate the computation of the areas of b i It also exemplifies Boileau’s constant activity of mind, that he published, at this early date, a report of his own ‘On the Practica- bility and Expense of a Plan proposed for Constructing Docks in Diamond Harbour on the River Hooghly, and for uniting them with Calcutta by a Railroad, together with an Hstimate for the same.” It was at this time that the interest of the Royal Society in magnetic observation, which had been originally stimulated in 1836 by. a letter of Humboldt’s to the then President (the Duke of Sussex), and had been maintained by the zeal of Major Sabine, was at its height. The Society recommended the Court of Direc- tors of the H.I. Company to take part in the institution of mag- netic and meteorological observations, which (chiefly through the influence of Colonel Sykes) they decided to do. Boileau and two officers of the Madras Engineers, Lieutenants Ludlow and Elliott, were appointed to establish and take charge of observatories at Simla, Madras, and Singapore respectively, and all three went to Dublin in November, 1839, to receive from the late Rev. Dr. Humphrey Lloyd, of Trinity College, a course of that preparation for their duties which that eminent philosopher alone could then impart. Captain Boileau, before he left again for India, was elected a Fellow of the Royal Society, and also a Fellow of the Royal Astronomical Society. The three Indian Engineer officers embarked in February 1840 for Madras, reaching that port in June, where they separated, and Boileau with his instruments proceeded to Calcutta. He reached Simla on the 24th of September, some weeks before the arrival of his assistants with the instruments. He had taken observations of dip on his palankin journey, by the way, at Allahabad, Futteheurh, Bulandshahr, Karnal, Ambala, and Bar (at the foot of the hills on the road to Simla). He was also fortunate in securing for his magnetical campaign the hearty interest of the Rev. John Henry Pratt, after- wards Archdeacon of Calcutta, a man not less well known for his scientific acquirements than beloved for his character. Captain Boileau selected for his observatory a site on what was then called Bentinck Hill, but which has since been known as Observatory Hill, and which in the rapid revolution of administrative events in village lands by the officers of the Government Revenue Survey, and have gone through several editions. They are the first ever published for angular values to single minutes of arc, or to five places of decimals for distances. Their great utility, both for the above purposes and for surveying in general, has been acknow- ledged by letters from the United States of America, from the Brazils, from Australia, and from India.’ LBoileau’s tables are in habitual use at Cooper’s Hill College. Traverse tables are intended to save the calculations of triangles in ordinary surveys, by showing by inspection the amount in linear measurement of the difference of lati- tude and departure (¢.e., of longitude) for any bearing and distance. iil India has recently been selected as the site for the Viceroy’s official residence. The observations were continued from 1841 to 1846, though their maintenance had been occasionally menaced with interruption. This is referred to more than once by Boileau in the correspondence which he maintained, during the earlier years of his work at Simla, with Dr. Humphrey Lloyd. Under date 15th September, 1842, he writes :— ‘“‘ We have now in Simla all our Chiefs, viz., Lord Ellenborough, the Governor of the N.W. Provinces, and the Commander-in-Chief. The Governor-General has not yet been to see my works, but he has expressed himself in such terms respecting the Observatory that if it is left to his Lordship’s pleasure, the continuance of its observations will be short indeed. He calls the establishment of the Company’s corresponding stations an Hnelish (or rather a Home) job; and I have not the least doubt that both himself and the Government of India at Calcutta are doing all they can with the Court of Directors to procure the abolition of the Indian Observatories. Ses Government have twice applied to me to know how long my “ experi- ments” and ‘tthe Magnetic Survey” are to continue, and I have both times replied that the series of corresponding observations upon which I was engaged could not terminate until the 30th June, 1844, at midnight.” 18th December, 1842: “ We have got rid of all our great people, but my Lord Ellenborough has bid me attend his grand doings at Ferozpore on Christmas Day, whither accordingly I am bound on the 21st. This will cause a delay of three days in our opening the New Year, but there is no help for it. The return of our armies from Cabul promises a lasting peace to India, and I hope will also extend, almost indefinitely, the existence of the Observatory.” 17th October, 1842: “I see by the paper that H.M.’s Observatories are to be continued for three years, and if any good is to come out of our work, ours must be so too; though the Governor-General told me a few days ago that I must not reckon upon more than one year more at Simla. Since then the news of our victories and the re-establish- ment of British supremacy in Afghanistan has come in, and a few days since the accounts of peace with China, so that the mollia tempora fandi have arrived, and if you desire our co-operation for a further period, this is the time to ask for it. The peace saves our Government at least one and a half millions a year. The extra expense of four (three?) observatories is about £3,000 sterling per annum only. Lord Auckland absurdly estimated it at £10,000 a year, which was enough to frighten the Court of Directors out of their senses.” The same correspondence shows that Major Boileau not only kept iV the regular term-days, but certain others also privately arranged by Sir James Ross. Disturbances proved to be of pretty frequent occurrence. He sent home traces of eight in 1841, of three im the month of February, 1842, and others in August and September, 1842. These and the whole of the six years’ magnetical observations remain unpublished—a circumstance which might have lent greater force to the objections of Lord Hllenborough had. he been able to foresee it. There are some circumstances not easy to explain in connexion with this fact. That the magnetic observations were not published and do not exist in print is indubitable. But whether they were not printed is subject to a curious doubt. The Government did sanction for this purpose a printing establishment on a liberal scale, which was set up by Major Boileau first at Simla, then at Ambala (in or about 1847), and subsequently at Meerut, when he had been transferred to that station. And in a memorandum of his employments and services, in his own handwriting (dated 21st March, 1867) he enters :—“ Swper- intended the printing of the whole of the observations taken at the Simla station. . . . This press was exclusively employed by the Govern- ment N.W. Provinces in printing Government work, and acquired a high reputation for the accuracy and neatness with which especially its tablework (forms of figures) was executed. After completing the object for which it was established in connexion with the Simla Magnetic Observatory, it was transferred to the College for Civil Engineering at Roorkee, to which it is siill attached 2 Also in a letter to Sir Henry Lefroy, dated 18th July, 1883, General Boileau writes :—‘‘ The whole of the records and instruments of the Simla Observatory were destroyed by fire in the year 1858, owing to the cases in which they had been packed for transmission to England, on my retirement from the. Service in the beginning of 1857, having been transferred during the Mutiny from the safe depository in which they had been placed by me, into a store-room in which large quantities of dooly bedding had been stored away, and which had taken fire, or been set on fire, to the utter annihilation of the instruments, records, and printed observations of the Simla Station.” The letter last quoted proceeds :—‘“ Copies of the monthly aha tetas however, of the magnetic and meteorological observations of the Simla Station had been regularly forwarded by me to the Royal Society, and from them, with the sanction of the Government of India, and by the kind aid of the Royal Society, the meteorological observa- tions of the Simla Observatory were printed and published under my superintendence in the year 1872. “None of the magnetical observations of the Tile Observatories have been printed; although even at this distant time the results, if published in a condensed form, would be of great interest.” Vv It would appear that the meteorological observations, till printed in London in 1872, stood on the same platform with the mag- netical. And in the absence of any exact information, perhaps the impossibility of now recovering it, what I should deduce from Boileau’s statements is this:—that all the Simla observations were printed by him at his Observatory press, but that for some reason, very possibly his desire to accompany the publication with prolegomena and some indication of results, for which he never found time in India, he was induced to defer their issue: that he had intended to carry the work to completion in England after his retirement and establishment in a home there; but that, in consequence of the break- ing out of the Mutiny shortly after his departure from India, the despatch was delayed, and in the following year the fire occurred which consumed the whole. We may here insert a list of books of tables of divers useful kinds which were prepared and issued by Boileau during his residence at the Observatory, or in the immediately succeeding years. 1. Tables (from Apjohn’s formula) for determining the Hlastic Force of Aqueous Vapour. 2. Ivory’s Tables of Mean Astronomical Refractions; Revised and Augmented. 3. Mathematical Tables; comprehending Logarithms of all Numbers from 1 to 10,000, also Logarithms, Sines, Tangents, and Secants, to Six Places of Decimals. 4, Oltmann’s Barometrical Tables. 5. A Collection of Tables—Astronomical, Meteorological, and Mag- netical; also for Determining the Altitudes of Mountains; Com- parison of French and English Weights and Measures, &c. 6. Tables of Wages and Rent; of the Value of Goods; for convert- ing Seers and Chittacks into Decimals of a Maund, also Annas and Pice into Decimals of a Rupee. 7. Tables for facilitating the Computation of the Time fant single Altitudes. Roorkee, 1858. To these we may add — 8. Meteorological Observations made at the Magnetic and Meteoro- logical Observatory at Simla during the years 1841-45, under the direction of Lieut.-Colonel J. T. Boileau, F.R.S., Superintendent of the Observatory. Published by Order of the Right Hon. the Secre- tary of State for India in Council. Boileau’s work while at Simla was by no means confined to that of the Observatory. During the years he spent there a great variety of occasional and useful tasks were either committed to him by Govern- ment, or voluntarily undertaken. After the Observatory work came to an end, Boileau filled the office of Superintending Engineer successively at Ambala and Meerut, till nal in 1854 he was transferred to Agra, on the reorganisation of the P.W. Department, as Chief Engineer to the Government of the N.W. Provinces. In addition to the duties of the former office, while at Ambala he undertook to codify and co-ordinate the chaotic mass of Standing Orders of tlhe Department, extending over a period of nearly seventy years. The result of this voluntary labour, Boilean’s Code as it was called, to which he added a full Index and Series of Forms, was printed at the expense of Government, and became some years later a most valuable aid when a Committee was appointed by Government to draw up a systematic code of rules and procedure for the Department. Colonel Boileau retired from the Service February 24th, 1857, with the usual honorary step which made him Major-General. Boileau’s life in India had been characterised by acuteness and vivacity of intellect, by an unresting and devouring activity of mind, and by extraordinary versatility and variety of work. He hardly attained the success that some of these qualities would have led one to expect, but at the same time the list perhaps suggests some reasons for this. And it is a fact that his joyous and buoyant temperament, indeed his exuberant spirits, often showing themselves in proceedings of an eccentric character, made him better known to the Anglo-Indian community than his intellectual gifts or practical accomplishments. Indeed, his sayings and doings were the subject of many widely current anecdotes, which, in some cases, were founded on the merest iota of fact, and in some others were purely mythical. It was really in the thirty years of life following his retirement that Boileau’s best qualities were drawn out to most valuable purpose, and won him wide and warm regard. He was, to be sure, as versatile and active as ever; thus he became the most energetic of vestrymen at Kensington, and as Chairman of the Building Committee which erected the handsome Town Hall there, he was indefatigable in his supervision of the work and of its financial details. He was for years a most zealous member of the Volunteer body, in which, however, he steadfastly declined the command of his corps (the 1st Middlesex Rifles) which was pressed on him, insisting on carrying his rifle as a private in the ranks. He was for some time on the Council of the Royal Society, and acted as auditor of its accounts; besides serving actively at one time or another on the Committees of various charitable, religious, or other useful Societies. But that which especially developed in General Boileau, and characterised him for the last twenty years of his life, was the active practical benevo- lence and devotion to the work he took upon himself as Committeeman, and eventual Chairman, of two noble institutions, viz., that of the Soldiers’ Daughters’ Home at Hampstead, and that of the Officers’ Daughters’ School at Bath (the latter having also for some years a succursal at Roehampton). To these institutions he grudged no Vil labour, and spared no fatigue. The children of the Soldiers’ Daugh- ters’ Home were always termed by him his ‘“‘ red chickens,” and when wearied with work his greatest refreshment was to visit the Home and to get surrounded by their smiling faces and happy voices. ‘“ At any hour of the day or night, and in any weather, he would go to the Home, if his presence was required; and, as long as his strength permitted, he would sometimes walk the whole distance from his residence at Notting Hill before breakfast. On occasions of joy or sorrow at the Home he was never absent, and he was ever at the beck and call of the excellent matron, with whom he worked in unbroken harmony for the twenty years he occupied thechair. . . . Allhis own servants were drawn from the Home, and he would always declare that they were unsurpassed.’ He cared for them as if they had been his own children, and he was repaid by their attachment to him. Every girl brought up in the Home who was in London at the time of his death sent a wreath to be laid upon his coffin. Beyond his constant weekday visits to Hampstead, he for many years before his last illness maintained a practice of going there on Sunday after- noon to be present at the Bible classes which the children attended. His exertions on behalf of the Royal School for Officers’ Daughters were not less devoted. He joined the Committee of this Institution in 1872, and in 1880 became Chairman in succession to Sir Henry Lefroy, when the latter went as Governor to Tasmania. When it was deemed expedient some years ago to close the succursal at Roehampton, and to extend the buildings at Bath to receive the additional pupils there, all the details of this change and the new construction at Bath were conducted under General Boileau’s close supervision. Till his last illness he never altogether lost his buoyant spirits or his oddities; but in the constant exercise of benevolent effort these latter had taken a riper and sweeter form than in the old Indian days. In May 1886 the illness began which, with sundry fluctuations, and borne with patience and devoutness for six weary months, terminated in his death, Sunday, November 7th. I have given some examples of his ever-active mind and versatile capacities. I may add that till he left India he played both the flute and the violin. He could, I am told, quote Hafiz with faultless pro- nunciation and expression; he spoke Hindustani, I know, with a ver- nacular swing which was rarely equalled in the mouth of an English- man; whilst his memory was stored with old Hindu saws and rhymes, ever ready to be produced on appropriate occasions to appreciative hearers. He was also a fair Latin scholar. And for a long time he was a diligent attendant at and participator in the proceedings of the Royal United Service Institution. During the earlier discussions on rifle construction he took a serious part in them, and himself invented a rifle. ) Ls bee C Vill Sir Water Etpiot, K.C.8.1., LL.D., who died at his seat, Wolfelee, near Hawick, N.B., on the 1st March, 1887, at the mature age of 84 years, was born in Hdinburgh, January 16th, 1803, the eldest son of James Elliot, Hsq., of Wolfelee, by his marriage with Caroline, daughter and co-heiress of Walter Hunter, of Polmond, county Peebles. Sir Walter was educated at Haileybury College, where he obtained the certificate of “highly distinguished,” and entered the service of the Hast India Company in 1820. In 1823 he received his first appointment as Assistant Political Agent for the South Mahratta District. After holding various other offices in the Revenue and Political Departments of the Madras Government, he was made, in 1837, Private Secretary to his cousin, Lord Elphinstone, then Governor of Madras. From 1837 to 1854 he was a Member of the Board of Revenue, and during that time was intrusted with the supervision of the Northern Circars, then in a very unsatis- factory condition. In 1854 he became Member of Council, and retained this position until he retired from the Indian Service in 1859. . Throughout his career in Indiaand during the whole period of his subsequent life in this country until a very recent date, when his eye- sight failed him, Sir Walter Elliot was constantly at work on various points connected with the Natural History, Ethnology, Antiquities, and Languages of India, in all of which subjects he was deeply versed and took the most profound interest. Though his publications were not very numerous, his notes and collections in all these departments were extensive, and were in many cases utilised in the way of contributions to the writings of his fellow-workers in these various branches of science. One of his most important earlier papers was a Catalogue of the Mammals found in the Southern Mahratta country, published in the ‘Madras Journal of Science’ for 18359 which was one of the first attempts made to give a connected account ~ of the mammal-fauna of the Indian Peninsula. In the same journal and in the ‘Journal of the Asiatic Society of Bengal,’ will be found other zoological contributions from his pen. Sir Walter was also well acquainted with Indian plants, and after his return to this country contributed several articles to the ‘Edinburgh New Philosophical Journal’ on the farinaceous grains and the various kinds of pulse used in Southern India. But it is, perhaps, as an Indian antiquarian that his name will be ultimately best known to posterity. The sculptured slabs from the famous Buddhist Tope of Amravati which adorn the walls of the great staircase in the British Museum, were procured by him, and presented to the Court of Directors, who transferred them to the national collection. Besides these, a splendid collection was accumulated at Wolfelee of coins, copper plates, arms, and other Indian ethnological objects. Sir Walter Elliot was for 1x many years a constant attendant at the meetings of the British Association for the Advancement of Science. Sir Walter was an ardent collector of Indian coins, and a leading authority on the subject. His principal numismatic work was a memoir on the “‘ Coins of Southern India,” which forms the second part of the third volume of the International ‘ Numismata Orientalia.’ Sir Walter is in fact the only man who has worked systematically on Southern Indian coins, a neglected subject to which Marsden and Prinsep made some small contributions. In the work above men- tioned, he has laid a solid platform, on which future Indian numismatists may proceed to build. With his habitual liberality he transferred more than 300 of his most valued coins to the collection in the British Museum. Besides this most important work, Sir Walter published two papers on the same subject in the ‘ Madras Journal of Literature and Science’ (new series, vol. 3 and 4), under the title of “‘ Numismatic Gleanings.” In private life, it may be said in conclusion, Sir Walter Elliot was one of the kindest and most amiable of men. His sweet and genial disposition, and great liberality in every way, endeared him not | only to his immediate friends and relations, but to all those with - whom in various ways he came in contact. In 1839 he married — Maria Dorothea, eldest daughter of Sir David Hunter Blair, Bart., of - Blairquhan, who survives him, and by whom he leaves a family of three sons and two daughters. Sir Walter was elected F.R.S. in 1878, and LL.D. of the — University of Hdinburgh in 1879. He was made a Knight Com- mander of the Star of India in 1866. Pil... Se Sir JosepH WuHiTwortH was born at Stockport on December 21st, 1803. His school education terminated at the age of fourteen. He was then sent to an uncle, a cotton-spinner in Derbyshire, with the intention of his being brought up to that business. His mechanical tastes were, however, too strong, and in 1821 the idea of cotton- spinning was given up, and he obtained employment and experience for four years in the works of different machine-makers in Man- chester. In 1825 he went to London, and was engaged successively with several of the most important engineering firms, amongst them Maudslay and Holtzapffel. He also worked with Clement, who was engaged in the construction of Babbage’s calculating machine. In 1825 he married his first wife, Fanny, youngest daughter of Mr. Richard Ankers. In 1833 Whitworth returned to Manchester, and set up as a tool-maker on his own account. His business and repu- tation rapidly increased. In 1840 he read a paper before the British Association on his method of preparing accurate metallic plane sur- d x faces, a method which he had devised when with Maudslay in London, and in 1841 he read a paper before the Institution of Civil Engineers on “ An Uniform System of Screw Threads.” During the next ten years he introduced his system of standard gauges and perfected his measuring machine, an instrument which is capable of detecting a difference in size of one millionth of an inch. In 1853 he was appointed as one of the Royal Commissioners to the New York Exhi- bition, and in the following year his attention was directed, at the request and with the aid of the Government, to the improvement of fire-arms. Since that time the subject of fire-arms, large or small, interested him more than any other to the day of his death. He was President of the Institution of Mechanical Engineers in 1856, and in 1857 he was elected a Fellow of this Society. In 1868 Whitworth founded the Engineering Scholarships which bear his name. He pro- vided an annual income of £3000, to be distributed as scholarships for the encouragement of the study of the theory and practice of mechanics. In July, 1869, he was created a baronet. In 1870 his first wife died, and in 1871 he married Mary Louisa, widow of Mr. Alfred Orrell. The present works of Sir Joseph Whitworth and Company, Limited, were opened in 1881. Since then they have received a rapid extension and development, and now undoubtedly contain the finest collection of powerful machine tools in the world. Of late years the state of Sir Joseph Whitworth’s health usually necessitated his spending the winter in the South of France. He died on the 22nd of January, 1887, at Monte Carlo, and was buried in Darley Dale church- yard, near his country residence at Stancliffe. One characteristic ran through the whole of Whitworth’s work as an engineer—insistance upon the very highest standard of excellence both of workmanship and material; and it is to this rather than to any specific inventions or discoveries that his great success and reputation are due. The principle of his method of preparing true planes was the simple one that if any two of three surfaces accurately fit each other, each of the three must be plane; in addition to adopting this funda- mental principle, he used a scraper for forming the surfaces, instead of the practice previously in vogue of grinding the surfaces together. In the matter of screw threads and standard gauges, Whitworth insisted on the desirability of all engineers adopting the same standards, and working with them to the utmost attainable accuracy. He adopted the inch as his unit, but divided it decimally; and this intro- duction of the decimal system to the British workman must in itself have had a very material educational effect. In fire-arms, both small arms and artillery, the principal points on which Whitworth insisted were, the use of a long projectile with a great angular velocity of rotation about its axis, and the use of polygonal rifling of the barrel instead of grooves, the projectile being formed to fit the barrel and so XI secure a large bearing surface. Probably the improvements in the manufacture of steel which are associated with the name of Whit- worth have done more for the development of the most modern artil- lery than has either of the features of his system of rifling. His improvements may be broadly said to consist in three points: first, insistance upon obtaining the best material for the purpose in the highest. purity ; second, in compressing the molten steel in the ingot; third, in forging under a hydraulic press instead of a steam hammer. Whitworth’s published writings are comparatively few in number, but these have a permanent interest and will always be instructive. His fame is rather written in iron and steel, and in the daily practice of the mechanics who have been directly or indirectly trained by him, than in the journals of the learned or technical societies. d.. Hi: Dr. Atten THomson, one of the most distinguished anatomists and embryologists of his time, was born in Edinburgh, Midlothian, Scot- land, on the 2nd of April, 1809, and died in London at 66, Palace Gardens Terrace, on the 2lst of March, 1884, in the seventy-fifth year of his age. His father, Dr. John Thomson, was a remarkable man, who at eleven years of age began life as a silk weaver’s apprentice. To this trade he was bound for seven years; and he continued to follow it in the town of Paisley for nearly two years after his apprenticeship had expired. His father, however, seeing that his son “took little interest in his trade,” bound him in 1785 (at the age of twenty years) to Dr. White, of Paisley ; and in this medical apprenticeship he con- tinued for three years. Subsequently, he became a pupil, in London, of William Hunter (brother of John Hunter), in his School of Anatomy at Leicester Square; and again returning to Edinburgh in 1793, he became a Fellow of the Royal College of Surgeons there at the age of twenty-eight. Having the year before ‘“ entered into engagements to form an alliance in business with Mr. Arrott (a Fellow of the College), he continued to live under Mr. Arrott’s hospitable roof till the autumn of 1798—a period of five years.” In 1815 he became a Licentiate of the Royal College of Physicians of Edinburgh; and in 1808 he obtained from the University of King’s College, Aberdeen, the degree of Doctor in Medicine. Having first practised in Hdin- burgh as a surgeon, he eventually rose to extensive practice as a physician. He was the first occupant of the Chairs of Military Surgery in the University of that city, and subsequently of General Pathology, both of which were founded on his recommendation.* In 1835, at the age of fifty-eight, he retired from active outdoor * Sir Alexander Grant’s ‘ Story of the University of Edinburgh,’ vol. ii, p. 441. VOL, XLII. e xX practice; and his life ended at the age of eighty-two. He retired with the reputation of being in his time “ the most learned physician in Scotland. To almost the last week of his life he was a hard student; and not even fourscore years could quench his ardour in discoursing science, morals, or politics. . . He was one of the marked men of that resolute and public-spirited class—the true Whig party of his day—which is now (1836) rapidly disappearing. His peculiar usefulness arose neither from his talents, his learning, his warmth of heart, nor his steadiness of principle, but from his enthusiasm. He never kuew apathy; and medicine being his field, he was for forty years the most exciting of all our practitioners and of all our teachers. . . Men, especially young men of promise, were inspired by his zeal and his confidence in the triumph of truth.”* ‘‘His example had, perhaps, more influence than that of any other individual in exciting the emulation of others.” f John Thomson was therefore aman acknowledged to be of great erudition, as his works show; and he made many important con- tributions to the medical science and literature of his time from 1765 to 1846. He contributed valuable papers to the earlier numbers of the ‘Edinburgh Review’; and continued (till his death in 1846) in habits of intimate friendship with its editor, Lord Jeffrey; continuing throughout his long hfe to be a man of great mark and influence in politics and science. | Such was the father of Allen Thomson—the subject of this notice. To be the son of such a father was already to be born distinguished, © and it was a still greater distinction that throughout the life of Dr. Allen Thomson, the best characteristics of the father came to be repeated in the son. His mother, Margaret Millar, was the third daughter of Mr. John — Millar, Professor of Jurisprudence in the University of Glasgow, to whom Dr. John Thomson (then in the forty-first year of his age) was married in 1806. It may be said, therefore, that Allen Thomson inherited by his birth a family connexion with two out of the four Scotch Universities—an inheritance which at once gave him a position of influence, of much advantagve to him in future years. Thus it came to pass that Allen Thomson was born, nurtured, and trained up in an atmosphere of learning and science; so that from his very earliest years the teaching of the son by the father was such as to lay the groundwork of a solid and purely scientific career, especially as an investigator and teacher of Anatomy and Physiology. * © Journal of Henry Cockburn,’ a continuation of the ‘ Memorials of his Time,’ 1831 to 1834, vol. ii, p. 164. t+ Dr. Richard Fowler, of Salisbury, in ‘ Biographical Notice of Dr. Thomson’ in 1st vol. of his ‘ Life of Cullen,’ reissued by Blackwood and Sons, 1859. XI With such a father and such surroundings, he was sure to have the best up-bringing and best direction. For the education of his boyhood he was sent to the Edinburgh High School, and had amongst his school-fellows John Murray—the eminent publisher— with whom he maintained a life-long friendship, also the present Lord Moncrief, and Thomas Constable. His professional education (mainly directed by his father) was begun at the Extra-mural School, and completed at the University of Edinburgh, and at the medical schools of Paris. In August, 1830 (at the age of twenty-one) he graduated as M.D. of the University of Hdinburgh, when his graduation thesis ‘‘on the development of the heart and _ bload- vessels in vertebrate animals,” was significant of the bent of his mind towards embryology, and foreshadowed the honourable dis- tinction which he subsequently achieved in that branch of biology which deals with developmental anatomy and physiology. It was published in the ‘ Edinburgh New Philosophical Journal’ (‘Jameson’s Journal’), commencing in 1830, p. 295, and continuing through three consecutive parts of that journal—a long contribution, fully and beautifully illustrated by drawings mostly the work of his own facile pencil, and many of them coloured. -At the time of his graduation he was President of the Royal Medical Society of HKdinburgh—a students’ society, which has contributed, and continues to contribute, not a little to the fame of the Medical School of that city, inasmuch as on the roll of its Presidents will be found the names of many, who in after-life became distinguished members and leaders in the pro- fession.* The year after graduation (1830) Allen Thomson became a Fellow of the Royal College of Surgeons of Edinburgh, as a necessary preliminary to his being qualified as a teacher there. 1t was his own wish and his father’s great desire that he should become a teacher of anatomy, and devote himself to anatomical and physiological pur- suits, for which he had displayed a decided predilection, and to which (as his thesis showed) he had already given a .considerable share of attention. With this object in view, and following the example of his friend Dr. Sharpey, he travelled by himself on the Continent in 1831. His copious notes show that he then particularly interested himself in the preparations in Vrolik’s Museum at Amsterdam, which he describes as a valuable collection in a state of excellent preservation. In it he notes a very fine collection of skulls of different nations and * “On its roll are inscribed the honoured names of Thomas Addison, Richard Bright, Marshall Hall, Henry Holland, and others of Metropolitan fame, with tliose of equal distinction associated with the Scottish and Irish Universities and Colleges, the men, in short, who have been most prominent in the history of British medicine and discovery during the last hundred years.” ‘ Anatomical Memoirs of Juhn Goodsir,’ vol. i, p. 76. e 2 X1V ages; and among those of executed criminals, of which several were those of murderers, ‘“‘there is the skull of Renier, a celebrated murderer of the worst class, which Gall, when asked regarding the collection, singled out and set aside as one clearly not belonging to a murderer!” He also notes ‘‘a protuberance inside the inner canthus of the orbit in a Jew’s skull, which Vrolik considered as peculiar to that race.” Next came notes of the Strasburg and the Berlin Museums. In this latter he made a great number of notes, especially bearing on the embryos of animals and the details of embryology generally ; dissections of varieties in the arrangement of the aorta and adjoining vessels; transpositions of viscera and teratology— making drawings as well as notes of what he saw. He was particu- larly interested in a human foetus (481) at three weeks, in which the branchial arches are seen; as well as the split between them into the pharynx. ‘‘ He was allowed to take this preparation from its bottle, to place it in a watch glass to make a drawing of it”; and to note its measurements. The marks of the eye and ear were both easily seen, and the superior maxillary fold connected with the inferior round the angles of the month. He notes also the heart partially divided into two ventricles. . On his return to Edinburgh after this short sojourn on the Conti- nent, he commenced his career as a teacher by starting as an extra- academical lecturer on anatomy and physiology. “In this under- taking he was associated with the late Dr. William Sharpey—(his senior by only seven years)—who ultimately became Professor of Physiology in University College, London, and with whom Allen Thomson maintained a life-long friendship of the closest possible character.”* Six years ago (March, 1881), when writing to his pupil, John Struthers, the distinguished Professor of Anatomy in Aberdeen, he says: ‘‘Sharpey and I lectured together at No. 9, Surgeon’s Square, from 1831 till 1836, when I left on account of my health being rather impaired. He taught the Anatomy and I the Physiology but in the later years, as my father urged me very much to prepare myself for Anatomy, I took a share in the Anatomy teaching by attending in the dissecting room and giving some demonstrations.” At this time a keen competition existed among the four teachers, who, in addition to the Professors within the University, divided among them the students who applied for instruction. It was no light undertaking at that time to become a teacher of Anatomy in Edinburgh. In 1828 a series of murders were brought to light which had been effected by two notorious criminals—Burke and Hare—for the money they would obtain for the bodies of their victims as material for the dissecting rooms; and for many years * M‘Kendrick, ‘“‘ Memoir of Dr. Allen Thomson,” ‘ Glasgow Phil. Soc. Proc.,’ vol. 15, 1884. XV afterwards the public mind continued to be excited by the recollec- tion of tragedies unprecedented in the history of mankind, and which scarcely subsided even with the passing of Warburton’s “ Anatomy Act” in 1832, which made it possible to obtain and dissect the human body in a legal way. In the University of Edinburgh, the third Monro filled the Chair of Anatomy, himself a good anatomist of the old school, who looked upon the new teachers with an easy disregard. But while Sharpey and Allen Thomson’s class between 1831 to 1836 had increased from twenty-two to eighty-eight, the majority of the students flocked to the brilliant but egotistical lectures of the famous Robert Knox, who in one year about this time had an extra-mural class of over 500 students. With unscrupulous virulence he brought his powers of ridicule and sarcasm to bear on all opponents, so that Allen Thomson and Sharpey came in for their full share.* About this time also a number of men who afterwards became famous were either students or extra-mural teachers, so that there was the keen contest of able intellects, and the rivalry of a noble ambition—the names of John Reid, Martin Barry, the two Goodsirs (John and Henry), Edward Forbes, W. B. Carpenter, John Hughes Bennett, are names which became distinguished in biological science; and in such an atmosphere of thought it is no wonder that Allen Thomson was encouraged to prosecute a purely scientific career.} All are gone; none now remain, and the melancholy death of Dr. Carpenter in 1885 severed the last link which connected them with what was undoubtedly “a brilliant epoch in the history of the Hdin- burgh Medical School.” In 1833, Dr. Allen Thomson travelled with his father on the Conti- nent for nearly three months, visiting the principal medical schools in Holland, Germany, Italy, and France. It is interesting to find in Dr. Allen Thomson’s brief journal of his travels, now before the writer, such entries regarding museum specimens as he saw might be useful for teaching purposes. In these notes he frequently makes a special memorandum of the preparations which should be made for the use of his class when he had the chance of doing so on his return to Edinburgh. He gives an amusing account of his journey to London by sea in those days. Hmbarking on board the ‘‘ Soho,” from Newhaven, on the afternoon of Saturday, 6th July, 1833, after two days’ sailing he reached Blackwall, whence he drove to London, and “put up at the Burlington Hotel, held by Atkinson Morley, in Cork Street, No. 35.” * “Life of Robert Knox, Anatomist,’ by Henry Lonsdale, 1870, p. 262; also Memoirs of John Goodsir,’ 1868, vol. i, pege 129. + M‘Kendrick, loc. cit. Xvi His first visits in London were to Dr. and Mrs. James Somervilie, John Allen, and John Murray; and at 30, Old Burlington Street, while waiting for John Allen, he first made the acquaintance of Sydney Smith. Medical education was then (1835) as now (1887), the serious subject of discussion; and Mr. Allen was of opinion that ‘“‘superior degrees should be granted by Universities, with full preliminary education ensured by a degree of M.A., and diplomas for general practitioners should be granted by chartered bodies, after- wards to be decided upon.’ He disapproved of legal prosecution of, the unlicensed, unless they do harm, or take titles they have no right to. Mr. Allen introduced his namesake, Allen Thomson, at this time to Lord and Lady Holland; and he was afterwards introduced to Lord Melbourne by Lady Holland, at Holland House, with the words, ‘“‘ Melbourne, allow me to introduce to you the future Professor of Anatomy in the University of Glasgow.” Allen Thomson had to wait, however, for fifteen years before that promotion took place. During this visit to London he also spent some of his time with his half- brother, Dr. William Thomson, James Simpson, and Dr. Carswell, who was then lecturing at University College, London. Dr. Allen Thomson was then much interested in the work of Clift and of Owen, at the Hunterian Museum, especially in the admirable series of preparations of comparative anatomy, and the beautiful manner in which vegetable structure is illustrated. He also records the significant memorandum, ‘‘ Make some preparations of this kind for myself.’ Breakfasting at Sir Astley Cooper’s, he had ‘‘a very i iteresting demonstration from him of his preparations of the thymus gland and testicle,” and mentions that “Sir Astley lectured with a great deal of spirit, and took the trouble to carry about 100 prepara- tions from one room to another.” Allen Thomson admired particularly the dry preparations of the thymus gland at different ages, in which the sacculi of the body itself are injected with wax, the arteries, veins, and particularly the lymphatics being injected and painted of various colours. Again he makes the memorandum, ‘‘ Make some of these preparations in the foetal calf.” Sir Astley then demonstrated his preparation of the structure of the testicles; and again, the memoran- dum, ‘“‘Dr. Sharpey and I must have some similar injections of the tubes with wax, &c.” He visited Guy’s Hospital Museum with Hodgkin, and there he bears his testimony to the beauty and accuracy of the wax models of diseases of the skin and of healthy anatomy, made by Joseph Townes. His father joined him on 15th of June, in London. On the 17th they started for Rotterdam. Thence by Dussel- — dorf and Delft to Bonn. MHe gives a very detailed account of the contents of the Museum at Bonn. He also describes the surgical “klinik,” “ conducted by questioning the students respecting patients XVII committed to their care. There were then two “ kliniks” for medicine, by Nasse, an advanced one, and an elementary one, intended to teach students how to conduct the advanced one. Meyer he also met, who had been Professor of Anatomy and Physiology at Bonn, and pupil of Kielmeyer, “of whose views and lectures he spoke in terms of high admiration.”” He met also Treviranus (the younger), Professor of Botany, Bischoff, Neumann, and Weber, the then Prosector. He notes a case in the dissecting room of the whole body of a man in whom there was complete situs inversus of all the viscera; and the writer well remembers what interest Allen Thomson took in the dis- section of a similar complete case of inversion of the viscera, which occurred in the dissecting room of the Glasgow University.* At Heidelberg he met Tiedemann, and carefully noted the contents of his museum. At Strasburg he met Ehrmann, and made copious notes of his museum. At Tubingen he met Autenrieth and his prosector, Professor Bauer. There he visited “the little dirty class- room in which Haller and Cuvier studied.” Thence to Stuttgart and on to Freybure, in Baden, and to Zurich. Here he met with Oken, then Rector of the University; also Schoenlein, Professor of Medicine, and other distinguished teachers; thence to Berne, Lausanne, and Geneva. He next visited Aix-en-Savoie, or Aix-les- Bains, and Milan. At Milan he was shown great attention by Professor Panizza, the successor of Scarpa; and at Parma, by Professor Tommassi, and by Pasquali, the Professor of Anatomy. Here he found the University partly broken up, and ahout half the building occupied as a barrack for soldiers, im order to repress the revolutionary spirit of the students. He notices in Professor Pasquali’s Museum of Anatomy, that “the dried muscular and arterial preparations were entirely painted,” and puts the question, ‘“‘ Why is this so seldom done; it seems to preserve the preparation well, and to make it more clear?” He afterwards, in Glasgow, adopted this method to a great extent in all dried preparations. At Bologna he notes that at present (August, 1833), the University is “in disgrace, and no lectures except the experimental ones are allowed to be given. The Professors are obliged to give their lectures at their own homes, and soldiers are placed at the doors.” He notes that ‘‘Comparative Anatomy is taught by Professor Alessandrini, under the name of ‘ Veterinary Anatomy, the former title being considered by the Pope as of a revolutionary nature.” He saw some beautifully injected foetal mem- branes, more particularly of the true allantoid of the mare, and of the endochorion and the decidua in the bitch. At Rome he notes that, “as in the rest of the Papal States, science * Described and figured in the ‘Glasgow Medical Journal’ for July, 1853. XVill is at present (September, 1833) much repressed by the fear of insub- ordination among the students; and that there is great difficulty in publishing or procuring scientific works.” | At Naples, with Dr. Vulpes, he met Dr. Asalini, of Messina, and visited the Museo Borbonico, the collection of antiquities from Pompeii and Herculaneum. He then visited both those places, and ascended Mount Vesuvius, the craters of which are minutely described in his carefully written journal. At the Grotto del Cune he saw the usual experiment of asphyxiating the dog. ‘The animal fell into a faint without convulsions, and the pupil dilated at the same moment that the voluntary motions ceased, which tcok place in from two and a half to three minutes after the animal was placed in the cave.” Genoa and Montpellier were next visited. There, he notes, a “ capital series of sterno-hyoid bones, bones of the skull, &c., for anatomical demon- stration, of which we ought to have some.” At Lyons he met Dr. Bennett, who was travelling with Lord Beverley and the Percy family, and renewed his acquaintance with M. Bouchet and M. Gensoul, who had both been in Kdinburgh. A very detailed but concise account is given of the anatomical, pathological, and comparative anatomy preparations in Meckel’s Museum, illustrated with some very beautiful pen and ink drawings, especially one of the heart in a case of partial inversion of the viscera, in which there was no vena cava infervor, but the cava superior was joined by the vena azygos before entering the auricle, the vene hepa- tice going directly into the auricle through the diaphragm. There is also a specimen with the aorta on the right side. Similar detailed records are given of Vrolik’s Museum at Amsterdam in 1851, and of » the Berlin Museum. Lastly, out of the experiences of these travels he formulates an extensive list of preparations ‘“‘to be made” for teaching purposes. At Paris, he met Rayer, Lerminier, Bouillaud, Roux, and Dalmas; and visited a separate ward for cholera patients in La Charité, where he “saw three women who were recovering under the influence of opium, ice, and bleeding !” It was by such Gonbaeaied travel, with the one object before hast of preparing himself for his duties as a teacher of anatomy and physiology, that he devoted himself with the greatest diligence and care to literary and scientific study, and to the study of languages. As travelling physician with the Duke of Bedford, he again spent a considerable time on the Continent, thereby perfecting his knowledge of German, French, and Italian. Of the men who mainly influenced the scientific life of Allen Thomson (besides his father’s influence) there are three especially to be noted, namely, John Allen, Dr. John Gordon, and Dr. Sharpey. Whiie still a house surgeon in the Royal Infirmary of Hdinburgh, X1X the father of Allen Thomson became the friend of John Allen, who was associated with him in the duties of the house, and with whom, up to the time of Mr. Allen’s death in 1843, he maintained an unin- terrupted friendship, and to the powerful influence of which over the fortunes of his life he has himself borne testimony in the dedication to Mr. Allen of the first volume of his ‘ Life of Cullen.’* Dr, John Thomson named his son Allen after his distinguished friend. Dr. John Gordon died in 1818, thirteen years before Allen Thomson began to lecture and teach Anatomy. After Dr. John Allen had ceased to lecture, Dr. John Gordon (having taught Anatomy and Physiology together for two years, 1808-1810) gave a course of Physiology separate from his course of Anatomy either in the winter ensuing or in the summer session; and for his character and work Allen Thomson had a great veneration. In writing, three years before he died, to Professor John Struthers, and referring to Gordon, he says: “‘I am especially pleased with your recognition of John Gordon’s character and work, which is not only perfectly true as regards himself, but gives some indication of the influence which my father exercised upon his pupils and the School of Edinburgh. I have still all Gordon’s papers, as well as John Allen’s.” Dr. Sharpey’s influence was that which made itself felt through a life-long friendship of the closest kind, bound together, as he and Allen Thomson were, in allied anatomical and physiological pursuits. Sharpey was one of the young men in Hdinburgh who owed the direc- tion of their studies and inspiration to John Thomson, and this — debt he repaid to his son Allen by an affectionate friendship. He was about twenty-nine years of age, and Dr. Allen Thomson twenty-two, when they commenced to teach Anatomy and Physiology together in Hdinburgh in 1831. This association subsisted during the four follow- ing years till 1836, when Dr. Sharpey became Professor of Physiology in University College, London. Dr. Allen Thomson spent the autumns of 1836 and 1837 at Rothi- murchus, in the Western Highlands of Scotland, near Aviemore, with the Bedford family, and afterwards. began his tour on the Continent with them. On his return in 1839 he was appointed (at the age of thirty) Pro- fessor of Anatomy in the Marischal College and University of Aberdeen, which he resigned in 1841. Returning to Hdinburgh in the autumn, he became once more a teacher of Anatomy in the * © Biographical Notice of Dr. John Thomson,’ prefixed to his ‘ Life of Cullen,’ p- 11, 1859. 1t is erroneously stated in a recent work, ‘ Life and Times of Sydney Smith, by Mr. Stuart J. Reid, 1884, p. 122, that John Allen and John Thomson were fellow apprentices to Mr. Arnot, an Edinburgh surgeon. There was no such apprenticeship, and the facts are those stated in the text, at page xi. b.& XX Extra-mural School, No. 1, Surgeon’s Square, at the age of thirty- two, where he continued to give systematic Jectures on Anatomy. At 11 a.m a lecture-room demonstration was given, and he taught in the dissecting room at one o’clock, assisted by demonstrators, the chief of whom was Dr. Gunning, who had accompanied him from Aberdeen, and who has since given to the University of Edinburgh a fund for prizes in memory of the teachers of his day. Professor John Struthers, of Aberdeen, bears the following testt- mony to the valued teachings of Allen Thomson :-— ‘Allen Thomson’s lectures on Anatomy were of a high order scientifically, and also in style contrasted favourably with the teaching in the other schools. His favourite subject was embryology. That could not come in much in the ordinary course, but in the summer of 1842 he delivered a special course of lectures on Development, in which he gave the resu!ts of his own researches, as well as those of the German observers. These lectures were illustrated by a very large number of beautiful diagrams, and were attended by many members. of the medical profession of Hdinburgh. His graduation thesis had been on the development of the heart and great blood-vessels in the vertebrata, showing an early direction of his mind to the subject of embryology. In that summer session he gave also a course of weekly lectures on the new Microscopic Anatomy, which followed the publi- cation of the great work of Schwann. In these lectures we heard muck of Schwann, Henle, and Kolliker, the latter of whom became his inti-- mate and life-long friend. To this time the microscope had not been much used in the school. The cell doctrine of Schwann had eleared up the confusion of the old general anatomy, although the revolution it was to effect in biology, in relation to the evolution as well as to the _ structure of organic forms, was hardly foreseen. Knox, whose forte was Comparative Anatomy and its bearings on human anatomy, was- satirizing the microscope, as he did most things. Sharpey had been using it in the investigation of cilary motion. John Goodsir, Con- -sservator of the Jarge and valuable Anatomical and Pathologieal Museum of the College of Surgeons, gave a few original lectures to- the Fellows of the Colleges on Cells; and on Germinal Centres; and Allen Thomson used it in his researches on Development. But then, and for years afterwards, the student had nothing of the microscope- ‘beyond the privilege of a peep through Allen Thomson’s and John. ‘Goodsir’s on a Saturday. The work which Allen Thomson did ‘during this year in Hdinburgh secured the success of his subsequent- career. His abilities as a teacher and observer were fully recognised. by the medical profession of Edinburgh.”’ The principal reason of his apparently sudden return to Edinburgh: may be explained by the fact that the Chair of Physiology in Hdin- burgh University was expected to become vacant by the transference- XX1 of Dr. Alison to the Chair of the Practice of Medicine; and to suc- ceed to the Chair of Physiology was the object of Allen Thomson’s laudable ambition.* Forthwith in the autumn of 1841 Professor Alison resigned the Chair of Institutes of Medicine or Physiology in the University of Edinburgh, and in 1842 Allen Thomson was ap- pointed his successor at the ave of thirty-three. The contest was severe with such formidable competitors as Robert Knox, John Reid, Hughes Bennett, and W. B. Carpenter. He held this Professorship in Hdinburgh for six years, and during that time he made several im- portant contributions to the science of embryology. He at the same time made the course on physiology systematic and complete, devoting himself entirely to the teaching of physiology proper. His lectures were prepared with great care, and a very elaborate synopsis of the day’s subject was written in chalk on blackboards for the students to copy, supplemented by drawings in coloured chalk, often very elabo- rate, and numerous wall diagrams. (A goodly MS. volume of such abstracts is in the writer’s possession. ) Allen Thomson’s familiarity with what was being done in Germany and France gave breadth and thoroughness to his teaching. He took great pains in making his drawings and in writing the heads of the lectures before the time of meeting; and like his friend Dr. Sharpey, he lectured mainly from short notes. He was systematic and methodical in everything, and took great pains to perfect his teaching in every way; and every course of lectures he delivered, whether to | a popular or professional audience, cost him much labour from day to day. On debatable points, and where definite conclusions had not been arrived at, he was careful to give us the views of observers on opposite sides, but it was tantalising in the extreme when at the end we could not learn what his own views were. ‘This was all the more distracting because he was so tull of knowledge, so clear in his state- ment, and so sound in his judgment. But the weak part (or perhaps strong part) in Allen Thomson’s mental development appeared to be so great an excess of caution in coming to a definite conclusion that he seemed always to hold his mind open to receive and digest new matter. He was thus prevented from making any broad generalisation with which his name can be associated. In all his researches his mind inclined more to the anatomical than to the physiological side of biology, having more to do with the development of form than the development of function; and when the Chair of Anatomy in Glasgow University became vacant by the death of Dr. James Jeffray in 1848, Allen Thomson became his suc- cessor at the age of thirty-nine. His introduction by Lady Holland to Lord Melbourne (in 1833) fifteen years before, and already referred to, shows that Allen Thomson was destined for that chair as a political * “ Memoir,’ by Professor John Struthers, p. 5. XXil inheritance; for then, as now, political connexion influences the chances of scientific appointments; and according as a Whig or Tory Government was in the ascendant, it was known that Allen Thomson or a political opponent would obtain the chair. But when Dr. Jeffray vacated his chair it was given to Allen Thomson with universal approval. He thus returned to the teaching of anatomy as to his first love, remaining constant to its teaching in the Glasgow University with great distinction in the professorship. He resigned it in 1877, when he was succeeded by its present distinguished occupant, Pro- fessor Cleland, who had been one of his demonstrators in previous years. During these previous twenty-five years of teaching anatomy and physiology, Allen Thomson had the unique experience of having been a professor in three out of the four of the Scottish Universities, and in all of them there is evidence that he worked with an indefatigable industry, not only in connexion with the immediate duties of the chair he held, but as a frequent contributor to scientific literature. Thus it came to pass that bis reputation, as a teacher and as a man of science, steadily increased; and at the end of his days he had become generally known throughout the scientific world as one of the most careful, judicious, accurate, and learned investigators and teachers of his favourite subjects. His very earliest work brought him reputation as an embryologist, and herein lay his speciality, so that throughout his long and busy life he was constantly making ‘important contributions to that department of science. He retired from his Chair of Anatomy in the University of Glasgow at the age of sixty-eight, having filled it forthe long period of twenty- nine years; and the work he accomplished there ‘“‘may be said to have been of two kinds: one, the introduction of the modern anatomy and methods of teaching it, by which he laid the foundation of the eminence and success which the Glasgow School of Medicine has since attained, an object which he had warmly at heart; the other, also contributory to that end, namely, the planning and erection of the New University buildings, in which great undertaking he was from: the beginning the moving spirit.” Succeeding a teacher who had held the Chair of Anatomy in Glas- gow for the long term of fifty-eight years, “‘it may be readily believed that Allen Thomson’s anatomy and methods were a new revelation in the old monastic building of that university.” As in Hdinburgh, when the third Monro at last (in 1846) made way for John Goodsir, the tide turned from the extra-mural school to the university ; so the Glasgow School of Medicine, when Allen Thomson became Professor of Anatomy, began to take the high rank to which the new colleagues who gradually gathered round him have contributed their part.* * ‘Memoir,’ by Professor John Struthers, p. 8. XXIll _ Shortly after coming to Glasgow, his son and only child was born in 1849. After that he took Greenhall in 1852, about eight miles from Glasgow, and afterwards Millheugh, where, as he always had a great, love of country life, he betook himself in the autumnal holidays, hospitably entertaining his many guests. Dr. Sharpey paid him regular summer visits. In 1855 came the meeting of the British Association in Glasgow, and among the guests then with him were his friends, Professor Kélliker of Wirzburg and Professors Retzius and Broberg from Sweden. In 1857 he rented Hatton House near Ratho, some miles from Edinburgh, and took great interest in this old place. There he became acquainted with the Lauderdale family to whom the property originally belonged, and there he received his old Kdinburgh friends, Syme, Bennett, Christison, Douglas Maclagan, Andrew Wood, Sharpey, and Kolliker. He took much interest in the garden and in garden work, and his acquaintance with Mr. Archer the artist, brought him into the pursuit of photography, which gave him a new pleasure. In 1862 he left Hatton, having purchased some acres of ground at Skelmorlie on the Clyde, where he built a house in accordance with his own plans. The later editions of Quain’s ‘ Anatomy’ were written here with Dr. Sharpey during the summer months; and here he also enjoyed his leisure moments with his friend Professor Kolliker, in the examination of marine animals. About this time the work commenced with the New University of Glasgow buildings, and from 1863, when the old college buildings were at last disposed of to a railway company, until 1870, when the classes met for the first time in the new buildings on Gilmorehill, Allen Thomson, as Chairman of Buildings Committee, was largely occupied with the anxieties and plans of the undertaking. He did all the duty of a ‘‘ Master of Works,” and his frequent exposure during the erection of the building brought on a tendency to rheuma- tism with a severe attack of sciatica. He further took a similarly active part in the planning and erection of the new—the Western Infirmary of Glasgow, the funds for which were mainly contributed by public subscription. This hospital is generally considered to be a model hospital. It has recently been greatly enlarged on the original plan ; and when Dr. Thomson retired from the Chair of Anatomy in 1877, he had already realised the pleasure of seeing the great success of the Glasgow Medical School which he had done so much to develop. | In 1870 he ceased to live at Skelmorlie, which he let and afterwards sold; and in 1871 his only son, John Millar Thomson, settled in London as one of the assistant demonstrators on chemistry at King’s College. The summer of this year was spent with his son and Mrs. Thomson in the Highlands of Scotland. ‘‘ It was,” he writes in | XXIV September, 1871, “a great success for me and Mrs. Alien to come here (Lynvilg-Avieore) for a holiday. I knew the country well from my residence at Rothiemurchus (close by) with the Bedford family in the autumn of 1836 and 1837; and I had most agreeable recollections of rambles among the Grampians and various parts of the neighbourhood. Mrs. Allen and I have not exactly rambled over the top of Cairngorm and Ben Muichdhui as we used to do when some- what younger, but we have really done an immense deal of walking for such old people, and have profited in health, and enjoyed our- selves to the full. The scenery is just what we hke—grand and open and yet beautifully combined with river, lake, natural wood, rock, and mountain. The birches especially are charming, and the remains of some of the old Caledonian forests of Scotch firs, some of the best existing. [am sorry to think the time of our remaining here approaches its termination, as I must be in Glasgow for meetings on the 20th, and intend to leave this on the 19th.” In 1872 he again went abroad with his family and with Dr. Sharpey to visit Professor Kolliker and other friends in Germany, and in the summer of that year he extended his tour to the north of Italy. The summer of 1873 found him once more travelling in the north of Scotland, and visiting his many friends. On his son’s marriage to Miss Aikin in 1875, he began to think seriously of retiring from his professorship; and after some delay, finally ceased his active connexion with the University of Glasgow in 1877—a connexion which had extended through different members of the family without interruption for 116 years. He then came to London, where he took a house next to that of his son. Here he took an interest in all that was going on in the world of science—occupying himself especially in the affairs and work of the Royal Society. He was now able to enjoy, and he much appreciated the quiet home-life he was able to lead in peaceful retirement, “‘ listening to the innocent prattle of his grandchildren.” It was a new pleasure and an amuse- ment to have them with him in his study. It is not easy to convey to others a sufficient appreciation of Dr, Allen Thomson’s numerous contributions to biological science. His earlier papers were on embryology, which throughout life con- tinued to be the favourite subject of his study and researches, working hard to keep pace with the rapid progress of the science. It was in this field that he won his laurels; and although his name may not be associated in the history of that science with any one great discovery (although he contributed many new facts), yet he will always be regarded as having done much, perhaps more than anyone else in this country, to make this difficult department of biological science familiar to British biologists. He directed his attention to it when few in this country did so, and did much by XXV clear and accurate description to make intelligible the writings of the German embryologists. No one rejoiced more at the attention given to it by a rising school of British embryologists, nor mourned more deeply the sad death on the Alps of its leader, the late Francis M. Balfour of Cambridge. He was one of the first also to bring under the notice of British physiologists the researches of Weber on the tactile sensibility of the skin, and he wrote largely for the ‘ Cyclope- dia of Anatomy and Physiology,’ edited by Todd and Bowman. The articles on ‘‘ Circulation,” ‘‘ Generation,” and ‘‘ Ovum,” are from his pen, and to the past and current editions of the ‘ Encyclopedia Britannica’ he contributed articles on kindred subjects. The article “Ovum” in the latter was prepared by him, and over it he worked to the end with ardent love and care; but since his death another hand has been employed to write it. He also wrote on physiological optics, more especially on the mechanism by which the eye accommo- dates or focuses itself for objects at different distances; and his name has long been associated with current editions of Quain’s ‘System of Human Anatomy,’ as editor especially of the descriptive parts of the seventh and eighth editions. In the seventh edition he was associated with Professors Sharpey and Cleland, in the eighth with Professors Sharpey and Schifer, and in the ninth and last edition with Professor Schafer and Professor Thane, both of University College, London. Alike with pen and pencil Dr. Thomson made important additions to their great work, especially ‘An Outline of the Development of the Foetus.’ He also edited a second edition of his father’s ‘ Life of Cullen.’ To the Royal Societies of Edinburgh and London, and British and Foreign medical journals, he contributed numerous special papers and articles. The Royal Society’s Catalogue contains the titles of about twenty papers by him. During his distinguished career Dr. Allen Thomson received many scientific honours. He was elected a Fellow of the Royal Society of Hdinburgh in 1838, and of the Royal Society of London in 1848, After his removal to London from Glasgow in 1877, he became first a Councillor of the Royal Society, and ultimately one of the Vice- Presidents. He was President of the Philosophical Society, of the Medico-Chirurgical Society, and of the Science Lectures Association in Glasgow, in which city he was also the first President of the Local Branch of the British Medical Association. For eighteen years he was a member of the General Medical Council for the Universities of Glasgow and St. Andrews jointly, from 1859 to 1877, where his ripe experience and calm judgment enabled him to do good service to the cause of medical education. In 1871 he was President of the Biolo- gical Section of the British Association at the meeting in Edinburgh, and in his address he reviewed the progress of biological science within the period of his own recollection. In 1876 the Association XXVI1 conferred on him its highest honour by electing him to the Presi- dential Chair. At the meeting at Plymouth in 1877, his calm, far- seeing, and philosophical address on his favourite topic, ‘‘ The De- velopment of the Forms of Animal Life,” was a masterly history of the gradual acceptance of the doctrines connected with the name of Darwin, whose important generalisations his open and receptive mind had long before accepted. In 1871 Dr. Allen Thomson received from his university the degree of LL.D., a degree which was also Hog a upon him by the Glasgow Duley in 1877. In 1882 he received the degree of D.C.L. from the University of Oxford ; and latterly he was elected to at least one Syndicate of the University of Cambridge to assist in the election of professors to the Biological Chairs. Whilst thus pursuing a purely and steadfast scientfic career, Dr. Allen Thomson was well known as one of the most active and influential men in the city of Glasgow. The friendly hand that wrote the obituary notice in the ‘ Glassow Herald,’ from which much of this memoir has been compiled, has given the following characteristic word picture of Dr. Allen Thomson : —‘‘ He took a deep interest in almost all departments of science. He was a ready listener, and always delighted to hear an account of anew investigation. Eager in the pursuit of truth himself, he, above all things, demanded accuracy. He was critical on all questions, and it required a great deal of fact and argument to lead him to a change of scientific opinion. Yet his mind was open and receptive, and he did not shrink from a change of view although it went against his precon- ceived notions. His own writings are models of clearness of state- ment and skilful marshalling of facts. Dr. Allen Thomson’s mode of teaching was of the same character. Method, order, precision of statement, and close reasoning shone in every lecture ; while there was also the persuasive eloquence of a great enthusiasm which capti- vated the listener.” As a teacher he was equalled by few and surpassed by none of the many colleagues amongst whom he taught. His education and sur- roundings made him a teacher, and to that work he bent all his energies. Those only who have been associated with him as demon- strators of anatomy in his dissecting rooms in Hdinburgh, Aberdeen, and Glasgow, can appreciate the daily labours he went through in preparing and arranging the material for his lectures and demonstra- tions. Personally he was much beloved by his students, who are generally remarkable for devotion to a teacher who takes pains to teach as he did. ‘‘In the social circle there was much gentleness and simplicity of manner, along with a keen sense of humour, while his domestic life throughout was characterised by a quiet kindliness, and that chivalrous attention to little details of personal courtesy which mark the true gentleman,” XXVI “One can never forget the kindly courtesy, the simplicity of address, the indescribable charm of his manner, the warmth of his friendship.” Loyalty to his friends was a typical characteristic of his affectionate nature. Inheriting the best characteristics of his father, with himself as with his father ‘‘he was a discerning and attached patron of youth- ful and friendless merit; so that there are many who owe their rise in life to him, and who bless his memory all over the world.”* In evidence of this we have the testimony of the Treasurer of the Royal Society, in his eloquent address on December Ist, 1884, when he said, in his notice of Dr. Allen Thomson’s death, that ‘‘ for acts of kind- ness there must be many besides myself who owe him a deep debt of gratitude.’+ The writer of this paper fully endorses this statement, and with gratitude acknowledges the many acts of kindness he received from Allen Thomson throughout a brotherly, or rather father-like friendship of more than thirty-six years. So also Dr. George Johnson, in his address as President of the Medico-Chirurgical Society, on March 2nd, 1885, thus spoke of him:—“ Dr. Allen Thomson will long be held in affectionate remembrance, not only for the extent and variety of his scientific attainments, but for his wisdom in council, the genuine kindly courtesy which gave an indescribable charm to his manner, and the enduring warmth of his friendship. On his retirement from the University of Glasgow, in 1877, his portrait, painted by the President of the Royal Scottish Academy of Arts, the late Sir Daniel Macnee, was presented by his friends and admirers to the University, and it now hangs in the Hunterian Museum, to hand down to future generations the cherished features of so beloved a man. A replica of this portrait was presented to Mrs. Thomson. Dr. Thomson has left a widow and an only son, Mr. John Millar Thomson, Demonstrator on Chemistry in King’s College, London, and Secretary to the Chemical Society of London. Up to within four months of his death Dr. Thomson appeared to be in excellent health, and looked forward to the pleasure of being in Edinburgh at the approaching tercentenary. In 1833 he went with his wife to Cannes, on January 3rd, and spent the cold months and spring there, and the summer was once more passed with his son, daughter-in-law, and grandchildren in the West Highlands of Scotland, with much pleasure in revisiting scenes with which he had been so familiar in earlier days. Suddenly, on December 14th, from his house in London, he wrote to say that his left eye had not been quite so well of late, and that Mr. John Couper and Sir William Bowman ‘ Memoir of H. Cockburn,’ p. 163, vol. ii, 1846. * Proceedinzs,’ p. 430, voi. 37. * Med. Chirurg. Soc. Trans.,’ vol. 68, p 7. 44+ * ie us Sah can eee XXVIll both concurred in the opinion that an iridectomy should be performed without delay. Accordingly, on the following day, Mr. Couper did an iridectomy on the left eye, on account of glaucoma. Nothing could have been more satisfactory than his recovery from the operation. The wound healed without pain, vision was maintained, and normal tension restored. About ten to fourteen days after the operation he began to experience lancinating pain referred to the ears and base of the skull, which he attributed to the east wind and rheumatism, as there was no change in either eye to account for the pain, and no external swelling. He woke in the morning to find that he had been struck blind of the right eye (which up till that moment had been perfect). Mr. Couper saw him forthwith, and found the tension _ normal, but there was a considerable area of the field of vision blind, the limit coming close to the centre. He could only distinguish large letters. Next day the main branch of the arteria centralis was seen to be plugged with blood-clot, the portion of vessel beyond the plug empty, and so for many weeks vision was entirely lost. From this it was feared that other arteries might be similarly plugged in adjoining parts. Dr. George Johnson also saw him with Mr. Couper and Mr. C. A. Aikin, and found that the cardiac valves were sound. It was thus probable that the vessels became plugged owing to degeneration of their coats at the plugged part. Gradually the plugging process extended, and about the fourth month after the illness began some local paralyses became developed, first in the left hand, thumb and forefinger, which passed away, and afterwards in the muscles of the right side of the face ; the vagus also became implicated, so that hiccough was more or less constant, relieved only by chloro- form. His strength was reduced by protracted suffering, and even- tually breathing became obstructed. He died at 66, Palace-gardens Terrace, W., on March 21st, 1884, in the seventy-fifth year of his age; and as he wrote of his friend Sharpey, so it may be written of himself: ‘ He had not a single enemy, and he numbered among his friends all those who ever had the advantage of being in his society.”* His memory will long be cherished in the hearts of thousands of his pupils at home and abroad, alike in civil and in military life. Wiss * ‘Proceedings,’ vol. 31, p. xix. ¢ ae 4 PROCEEDINGS OF Phi POY AL SOC TY: CONTENTS. ae dl January 6, 1887 SAVY! LUGS, UM °. Pee Le 4 I. On the Occurrence of Silver in Volcanic Ash from the Hruption of Cotopaxi of July 22nd and 23rd, 1885. By J.W. Mazer, M_D., ¥.RS., University of Virginia : i 5 5 ; Il. Preliminary Note on the Continuity of the Liquid and Gaseous States of Matter. By Witt1am Ramsay, Ph.D., and Sypnzy Youne, D.Sc. III. Note on Lepidodendron Harcourtii.and L. fuliginosum, Will. By W. C. Witiiamson, LL.D., F.RS., Professor of Botany in the Owens College and in the Victoria ia rorsitiy : : : ‘ IV. On the Organisation of the Fossil Plants of the Coal-measures : Heteran- gum Tikkeoides, Will., and Kaloxylon Hookeri. By Professor W.C. WitiiAmson, LL.D., ¥.R.8., Professor of Botany in the Owens College and in the Victoria University List of Presents January 13, 1887. I. Supplementary Note on Polacanthus Foxii, describing the Dorsal and some parts of the Endoskeleton imperfectly known in 1881. By J. W. Hoke, F.R.S. ; é 5 i : : : : : : If. The Reputed Suicide of Scorpions. By AuFrEeD G. Bovrnz, D.Sc, Fellow of University College, London, and Professor of Biology in the Presidency College, Madras Iii. Supplementary Note on the Values of the Napierian Logarithms of 2, 3, 5, 7, and 10, and of the Modulus of Common Logarithms. By Professor J. C. Apams, M.A., F.R.S. : , : 5 : 1V. On the Crimson Line of Phosphorescent Alumina. By Witt1amM CRooxzs, F.RB.S., V.P.CS. : i List of Presents For continuation of Contents see 4th page of Wrapper. Price Three Shillings. PAGE 10 16 o5 31 PHILOSOPHICAL TRANSACTIONS. Part I, 1886. CONTENTS. I. A Memoir on the Theory of Mathematical Form. By A. B. Kumpsz, M.A., E.R.S. II. On Evaporation and Dissociation.—Part I. By Professor WILLIAM RAMSAY, Ph.D., and Sypnry Youne, D.Sc. III. On Evaporation and Dissociation.—Part II. A Study of the Thermal Properties of Alcohol. By Witttam Ramsay, Ph.D., and SypNey Youne, D.Se. TV. On the Theory of Lubrication and its Application to Mr. Beauchamp Tower’s Experiments, including an Experimental Determination of the Viscosity of Olive Oil. By Professor OsBoRNE REyNnoxps, LL.D., F.B.S. Y. Further Observations on Enterochlorophyll and Allied Pigments. By OC. A. MacMony, M.A., M.D. VI. Researches on Myohematin and the Histohematins. By C. A. MacMounn, M.A., M.D. VII. An Experimental Investigation into the Form of the Wave-Surface of Quartz. By James C. McConnet, B.A. VIII. Description of Fossil Remains, including Foot-Bones, of Megalania prisca.— Part 1V. By Sir Ricnarp OwEn, K.C.B., F.B.S., &e. IX. Dynamo-Electric Machinery. By J. Hopkinson, M.A., D.Sc., F.R.S., and HE. Hopxrnson, M.A., D.Sc. Index to Part I. Price £1 8s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Tribuer and Oo., 57, Ludgate Hill. CONTENTS. February 3, 1887, TSOn the Waves produced by a Single Impulse in Water of any Depth, or oy ata paper Medium. By Sir W. ee Knt., LL.D., F.B.S. ane On the Meamation of Coreless Vortices by the Matien of a Solid through an inviscid incompressible Fluid. By Sir W. THomson, Kut., Be | Sretzy, F.RB.S., ° . Cs He ee 10, 1887. o a Restinibations: to the Metallurgy of Bisaaehe. By EDWARD Marry, HS a Oo S. A., F.C.S., Assoc. Roy. Sch. Mines ; b : , ot An Inquiry into the Cause and Extent of a special. Catone Beene _ between certain exposed Lepidopterous Pup and the Surfaces which — immediately surround them. By Epwarp B. Povuron, M.A., of Jesus” and Keble Colleges, Oxford, Lecturer in Zoology and Comparative as on at St. Mary’s ee Paddington ae si “OF CON, j ‘ y Cr For conti heen Lohtsbe see heh ‘Rage of Wrapper. wee coved dbshstbive APR 6 1887 § o Price Two Shillings and Sixpence. ens Yi Sa XIII. XIV. XV. XV 1; XVII. XVIII. XIX. XX. PHILOSOPHICAL TRANSACTIONS. Pee Part II, 1886. CoNnTENTS. . Effects of Stress and Magnetisation on the Thermoelectric Quality of Iron. By Professor J. Hwinea, B.Sc., F.R.S.E. . On the Sympathetic Vibrations of Jets. By Cuicuester A. BELL, M.B. . The Bakerian Lecture.—Colour Photometry. By Captain Apyery, R.E., F.R.S., and Major-General Fastine, R.E. The Solar Spectrum, from A 7150 to A 10,000. By Captam W. DE W. Asney, R.E., F.R.S. Description of Fossil Remains of Two Species of Megalanian genus (Meiolania) from ‘‘ Lord Howe’s Island.” By Sir RicnHarp Owen, K.C.B., F.R.S., &e. On Systems of Circles and Spheres. By R. Lacutan, B.A. On the Relation between the Thickness and the Surface Tension of Liquid Films. By A. W. Rernotp, M.A., F.R.S., Professor of Physics in the Royal Naval College, Greenwich, and A. W. Rucker, M.A., F.RS. On the Blood-Vessels of Mustelus Antarcticus: a Contribution to the Morphology of the Vascular System in the Vertebrata. By T. JEFFREY PARKER, B.Sc. Contributions to the Anatomy of the Central Nervous System in Verte- brate Animals. By ALFrrep SanpeERs, M.R.C.S., F.L.S. The Coefficient of Viscosity of Air. By Hersert Tomrinson, B.A., with the addition of two Notes, by Professor G. G. Stoxxs, P.R.S. The Influence of Stress and Strain on the Physical Properties of Matter. By Hersert Tomurnson, B.A. Index to volume. Price £1 15s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill. PROCEEDINGS OF °°. ag Mm THE ROYAL SOCIETY. = Ga ‘ VOL, XLIL | No. 253. . a : : i | CONTENTS. ‘ March 3, 1887. fe ce Ps - PAGE Last of Candidates . d 5 : d : : ; . ; é . 145 . I. Preliminary Note on a Balanoglossus Larva from the Bahamas. By “ oe W. F. R. Wexpon, M.A., Fellow of St. John’s College, Cambridge . 146 i ; a II. Studies of some New Micro-organisms obtained from Air. By @G. C. Uae -Freanxrann, and Prroy F. Fran xnanp, Ph.D., B.Sc. (Lond), F. C8., ies ‘< SIAN age eo LIT, On the Limiting Distance of Speech by Telephone. By ee HENRY : PeeOe eRe Re OEY. The Etiology of Scarlet Fever. By E. Kizty, M.D., F.R.S., Lecturer on Lo — Be General Anatomy and Physiology at the Medical School of St. e° Bartholomew’s Hospital, London , NES Te Tae St a a List of Presents . . ‘ , : Bee oh Bip i : Sea we Re = Bee git" ae . March 10, 1887. I. Note on Induction Coils or “ Transformers.” By JOHN Horxinson, E MEDS BRS ei el. es ge 4 II. Note on the Theory of the Alternate Current Dynamo, By Jouyn te he Hopxinson, M.A., D.Sc, F.R.S. EO NM PN REG | III. Transmission of ee through: gactasthrs Sei re. By Captain Be. eg porto. § Pp % List of Presents . : i" AY 33 387 : : ay i ; eo a ¥ Lirsenian vt ote a For continuation of Contents see pages of Wrapper. a a ee te | Price Four Shillings and Sixpence. — | | vance EE ——eeeeeeeeee eee XVII. XVIII. XIX. XX. PHILOSOPHICAL TRANSACTIONS. en Part IT, 1886. CoNTENTS. . Effects of Stress and Magnetisation on the Thermoelectric Quality of Iron. | By Professor J. Ewine, B.Sc., F.R.S.E. . On the Sympathetic Vibrations of Jets. By CuicuusteR A. Brent, M.B. . The Bakerian Lecture.—Colour Photometry. By Captam Asney, B.E., E.R.S., and Major-General Festine, R.E. . The Solar Spectrum, from 7150 to 410,000. By Captain W. DE W. ABNEY, R.E., F.R.S. . Description of Fossil Remains of Two Species of a Megalanian genus (HMeiolania) from ‘Lord Howe’s Island.” By Sir Richarp Owen, K.C.B., F.RS., &e. . On Systems of Circles and Spheres. By R. Lacuuan, B.A. . On the Relation between the Thickness and the Surface Tension of Liquid Films. By A. W. Rernoup, M.A., F.R.S., Professor of Physics m the Royal Naval College, Greenwich, and A. W. Ricker, M.A., F.R.S. On the Blood-Vessels of Mustelus Antarcticus: a Contribution to the Morphology of the Vascular System in the Vertebrata. By T. JEFFERY PARKER, B.Sc. Contributions to the Anatomy of the Central Nervous System in Verte- brate Animals. By Atrrep Sanpers, M.R.C.S., F.L.S. The Coefficient of Viscosity of Air. By Hrersert Tomiinson, B.A., with the addition of two Notes, by Professor G. G. Stoxzs, P.R.S. ~ The influence of Stress and Strain on the Physical Properties of Matter. By HersBert Tomiinson, B.A. Index to volume. Price £1 15s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1876, may be had of Triibner and Co., 57, Ludgate Hill. ERRATUM. Obituary rotice of Thomas Andrews (No. 250) :— Page xii, line 5, for 5th read 26th. CONTENTS. ' Mee 8 Tato), By Pzrcy F. ee Ph. D, B. Sc, 1 B, C. Ba o ve and T. ve ee. ALR, . M. (Plate 3) Pact Il. By J.J. Tomson, M.A., F.R.S., Fellow of Trinity College and Cavendish Professor of Experimental Physics in the Universi of ¢ Cambridge ’ pi : 3 3 j 3 é Ure Conduction of Heat i in Liquids. By C. Cures, B.A., King’s College, a _ oe Pye au acta . e . e s ° e@ « ry en? s For continuation of Contents see 4th page of Wrapper. Aik : . aka : ty is 7.8 Ri wet 8, “\ a) THSONIAN peree Price Tu wo Shillings, - = oe ee Part II, 1886, ‘CoNTENTS. X. Effects of Stress and Magnetisation on the Thermoelectric Qualys of Tron, By Professor J. Hwine, B.Sc., F.R.S.E. | 4 XI. On the Sympathetic Vibrations of Jets. By Guicnkarem A. BELL, es XII. The Bakerian Lecture——Colour Photometry, By Captain ABNEY, R.E eee E.R.S., and Major-General Festing, R.E, , __XTII. The Solar Spectrum, from 7150 to 410,000, By oe w. BE moe a Asyuy, R.E., F.B.S. Meigs ast XIV. Description of Fossil Remains of Two Species of a Megalanian genus” | - (Meiolania) from’ “Lord Howe’s Island.” oe Sir Ricwarp Owns ‘K.C.B., F.RBS., &. : XV. On Systems of Circles and Spheres, By R. Likoeeae B.A. XVI. On the Relation between the Thickness and the Surface Tension of Li Films. By A. W. Reryozp, M.A., F.R.S., Professor of Physics ‘in the 5 Royal Naval College, Greenwich, and A. W. Ricker, M.A.,F.RS. XVII. On the Blood-Vessels of Mustelus Antarcticus: a Contribution to Ga Morphology of the Vascular pa in the Vertebrata. By T. JEEFERY é , PARKER, B.Sc... : : “XVILL Contributions to the ‘Abltoms of the Central Nervous ga in 1 Verto ie ~~~ brate Animals. By Anrrep SanpErs, M.RB.C.S.,F.L.8. a a Ba x. The nested of Viscosity of due By HErBerr TomINsoN, B. om: with - the addition of two Notes, by Professor G. G. Stoxzs, P.R.S, ae b oak XX, The Influence of Stress and Strain on the Physical go oe Matton. i : ‘By Herpert ‘TOMLINSON, B.A. PS Index to volume. : | if ss eee : eee CGR Price £1 15s, : / Extra volume (vol, 168) containing the Reports of the Naturalists attached fu tl | | Transit of Venus Expeditions, Price £3, s Sold by fitasiioe and Sons, Separate copies of Papers in the Philosophical Transactions, commencing with ] may be had of Triibuer and Co., 57, Ludgate Hill, a; iP. _ PROCEEDINGS OF THE ROYAL SOCIETY PeVOL., XLT. No. oye ( gga Stet 7 7 Net b it R o> I. Report of the Observations of the Total Solar Eclipse of August 29, 1886, made at Carriacou. By the Rey. 8. J. Perry, 8.J., F.R.S. List of Candidates . If. Note on the Microscopic Structure of Rock Specimens from three Peaks in the Caucasus. By T.G. Bonney, D.Sc., LL.D., F.R.S., Professor of Geology in University College, London : ; : , III. On the Distribution of Strain in the Earth’s Crust resulting from Secular Cooling, with special Reference to the Growth of Continents and the Formation of Mountain-chains. By CHarites Davison, M.A., Mathe- matical Master at King Edward’s High School, Birmingham IV. Note on the Geological Bearing of Mr. Davison’s Paper. By T..G. _ Bonney, DSc., LL.D., F.R.S., Professor of Geology in Bes - College, Toran c i ; : 5 é : 255. 325 328 © VY. Note on some Experiments on the Viscosity of Ice. By J. F. Matn, | RIGA DENCs 3 : ; : : : : : : : - 329 VI. The Tubercular Swellings on the Roots of the Leguminoser. By H. Marsnatn Warp, M.A., F.L.S., Fellow of Christ’s College, Cambridge, and Professor of pctuny: in the Forestry School, Ce Indian College, Cooper’s Hill . : : p é s : VIL. The Proteids of the Seeds of Abrus precatorius (Jequirity). By Sipnry Martin, M.D. Lond., Fellow of University ae London, and Pathologist to the Vibtoria Park Hospital d t t VIII. On the Diameters of Plane Cubics. Preliminary Notice. By J. J. WALEER, F.R.S. : : : : ‘ : 5 Rar List of Presents . i : LR Re : ; : BARR i For continuation of Contents see 4th page of Wrapper. Price One Shilling and Sixpence. BH ae 331 334 336 Tres tera ete PHILOSOPHICAL TRANSACTIONS. Part IT, 1886. | _ ConTENTS. X. Effects of Stress and Magnetisation on the Thermoelectric Quality of Iron. By Professor J. Hwine, B.Sc., F.R.S.E. XI. On the Sympathetic Vibrations of Jets. By CuicHzuster A. Bett, M.B. XII. The Bakerian Lecture.—Colour Photometry. By Captain Asyzy, R.E., E.R.S., and Major-General Fustine, R.E. XIII: The Solar Spectrum, from A 7150 to A 10,000. By Captain W. pE W. ABNEY, R.E., F.R.S. XIV. Description of Fossil Remains of Two Species of a Megalanian genus (Meiolania) from ‘Lord Howe’s Island.” By-Sir RicnHarp OWEN, K.C.B., F.R.S., &. XV. On Systems of Circles and Spheres.. By R. Lacuuan, B.A. XVI. On the Relation between the Thickness and the Surface Tension of Liquid Films. By A. W. Rernoup, M.A., F.R.S., Professor of Physics in the Royal Naval College, Greenwich, and A. W. Rucker, M.A., F.R.S. © XVII. On the Blood-Vessels of Mustelus Antarcticus: a Contribution to the Morphology of the Vascular System in the Vertebrata. By T. JEFFERY PARKER, B.Sc. XVIII. Contributions to the Anatomy of the Central Nervous System in Verte- brate Animals. By ALFRED SanpeErs, M.R.C.S., F.L.S. XIX. The Coefficient of Viscosity of Air. By Hrersurt Tomuinson, B.A., with the addition of two Notes, by Professor G. G. Stoxzs, P.R.S. XX. The influence of Stress and Strain .on the Physical Properties of Matter. By Herserr Tomurnson, B.A, Index to volume. Price £1 15s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the i Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. i, Separate copies of Papers in the Philosophical Transactions, commencing with 1875, | may be had of Triibuer and Co., 57, Ludgate Hill. PROCEEDINGS OF. 3-5 THE ROYAL SOCIETY, VOL, XLII. No, 256. yi CON, cay W202 CONTENTS pic 2g 1987) | June 9, 1887. \. A ~ ard S y D Election of Fellows ; : : : : i) SOS ee June 16, 1887. : I. On the Structure of the Mucilage Cells of Blecknum occidentale (L.) and Osmunda regalis (L.). By Toxutazo Ito, F.L.S., and WaLTER . GAnpinku,; MAs "So, Pei Rare ee If. On Rabies. By G. F. DowDESWEZLt, MA, Ee. Z : Dae . 855 IIT. On the Tubercular Swellings on the Roots of Vicia Faba. By H. — MarsHatt WARD, M.A., F.L.S., Fellow of Christ’s College, Cam- bridge, Professor of Botany in the eee School, ae Indian - College, Cooper’s Hill ‘ : . 306 IV. The Electromotive Properties of ee Electrical Organ of Tor seas . marmorata. By Francis Gotcu, B.A., B.Sc., London, M.A. Oxon. 357 V. On Thermal Radiation in pe beclute deste e J. T. BorroMiLEy, M.A. . : . : : «S08, VI. On Figures of Equilibrium of Tolais Masses of Fluid. By @. H. Darwin, M.A., LL.D., F.RS., Fellow of Trinity ee and Plumian Pignes in Fhe Tater its of Cambridge . . 359 VII. The Influence of Stress and Strain on the Physical Properties of Mision Part I. Elasticity—continued. The Velocity of Sound in Metals, and a Comparison of their Moduli of Torsional and Longitudinal — Elasticities as determined by Statical and Kinetical Methods. a . Huppert Tomiinson, B.A. .. . 362 ° Vili. On Kreatinins. I. On the Kreatinin of Hanes as desangoined a that obtained from Flesh-kreatin. II. On the Kreatinins derived from the Dehydration of Urinary Kreatin. By GzroRGE ae FLEET JoHNSON, M.R.C.S., F.C.8., F.LC.. : : “ - 865 IX. On Gasterolichenes, a new ype of the ee neon Bye G. MassEE ° : . ; si : - 370 For continuation of Contents see 3rd and 4th pages of Wrapper. Price Five Shillings and Sixpence. 10. PHILOS OPHICAL TRANSACTIONS, ‘Part II, 1886, Price £1. lds. Sold by Harrison and Sons, 1887. The following separate Papers are now ready :— SERIES A. (Containing Papers of a Mathematical or Physical Character.) . On the Luni-Solar Variations of Magnetic Declination and Horizontal Force at Bombay, and of Declination at Trevandrum. By CHartEs CHAMBERS, E.R. 8., Superintendent of the Colaba Observatory, Bombay. Price 3s. . On the Properties of Matter in the Gaseous and Liquid States under various Conditions of Temperature and Pressure. By the late THomas ANDREWS, M.D., LL.D., F.R.S. Price 1s. . On Evaporation and Dissociation. Part III. 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