a ~ — " -y rn ae a a ee Se eh re eee ee eee ee eee ee ae ee ee ot rT ~ et ioe Nab eb hot ¥ We ; nvr We 8” pall, AAO Peet hm eh th Tons 7 thet actrees AO he hls Ge Leica SB hem edt tly apis se fenlic Wome RS oan DIP yee tn tle ed aera tt Reha tne tioe: Hyatt Geld te fiet ee eee ee Oct etm Tic Sends 1 feeb he eine ee ele a ae ante ES ee ae See ae eae 9° no eines = Ra HR rat kth lhe Lane RR ete WR re ~ . Te Tethnthe tortaw thet teed = beth he BePwe : en ee ee ee ee hm Lh lle - 2. Oates a , ee a eee ao : . Eereres : Patni emia tes aiadiaddaiatatermi oem cae . - ~e : - So ke a ee heel cereal olbtids tn ied Pobre ee ee Pet Het, = & tot 3 et at ten balhbeted i = bit eed Borin Pee rr ott nll beg tine ee te Or + Rha gt toe, hele Bm agg On te ee Sb waite Me = ue me ee ee a eee ee eee re Coa were te nll msibe em . an rthtene, 8 a~ (Mig PT ATG fy a Sa ne ° ‘ - a4 ~% = mee o eh Pe Sea Phe ee he i Rael gle OL ge EIN hg IT, ChE tee fe” 4 A SOS @ hee ina Ce ate - -"e : 7 » ene es tans on Sb he Fal rec Mitty i war twt
Oo -3 Sees 3 | B | eeoFenevwooeosee|oo |] =| e000 = Ge SI NNANNHHAANNRAANRH ION & OCODNO ss: 2 8 > NAN ~ paren © AG d | = is 2 lg 2 FHAPOWAAGAMHMSOM FO | OD = ron Wee | AAMAS AAA td ol ee ee o a FS st qt Sa : =e BS | og |panssavoooocoann |eo Foe = owas TO Oa si: = | teanadngedeneoon (aa So SS MMR ci IGGL [= ucts << oD = q eee ye. mieon S a) ee ROWS t? ial eo ee ee ee ae DONNA o ANNANMMANMANHMAND ION ROTso 2s ies) e = | rose ondangagome |ee €9 19 G0 10 = QUAN GU 9 a3 ed 29 aD ED cD ODED ED GIG | eo Oooo 2? oe C= G2 O2 2 > * - 8 00 FOTO SF |1ROANMANMORDRHOHAD! 7 S | ES RSEREREEEDDOS | oF eat | | a ie ss as Sooee s Fiwowe DA oO Ses — 1890.] + Temperature of the British Isles, 1869—1883. 311 | DRHRAAMB | ; x 0D HOHAH SF IROHNMAWORDAROANNM S me oN 6 | SS RRESRERREDHOD > gaies va = aa Ney SPeeSfe 4 co HOO —— mN | eee ost rt ot & O ai on onwo :: Ye) 4 i ~ susopdeanvospes | an o> et QU — imiso.s = H re ae aonedeoneovuane | wa 92 S010 rs) ors ictaent Se ROHO:: g |eowonnnsevecyne [an Sich o NANANNANNNANNANHNTR IAN COIs i, at ane D | 9 5 an aroadnenongedns [on MOOHn : = aaa Ns tea ee oS} OR. Ogio a 3 SS a aii. x BS = 5s S ; es be | aFODMnHoOrNnNNnDNOMD | OO = oN ie oe ai re) Era SS) ES 2 CO nO") Hk a SN Ors Meacs = & = NAANNANN FAA AAA es ON S MAH. - Se. |r | = S e S a o | = Me = oe 2 LD HAIN DiwW NO RWTH OM | 9O S HOS ‘e) =} RGIS Ii ens eke keke ne RN Ry DOHO:: 2S] 2 a Bob Biss, Sc 4 a et | owpooneryvooanne | me 9 D> — OOr sss T d | aayoorosonerepe (on mo Fe BB |MNNHAANANANR AANA H IAN Ci Qioins = 4 < on) peat i sorsouneooosoey |ae COM NN S ee le WOowS >. ra} ET 19 OO © DAMOANMANNMANNANNNMDION co Se 4 i rc | ANUANGDAAHMOAWMWIOW DO | FO Teo ed Ss hn ogee he e\eiieS 6 ¢ bi) rl Bec DADAD ASH ° ] < 2 oS tO tO nH Hn a AOHNMFWMORDRO-ND! a S$ | SRRARSER Veh ee eect iecs oat les ee He Slee POSSE e420 O10 © | 2a cS aon “ (Cy 312 Mr. R. H. Scott. The Variability of the .[Mar. 27, PRBRAG ‘ 4 CO FOHOA RB 1QOnN G2 1D LOI WO D mi gt op s arin 6 | SRE REE EEEERDHHOD! fp eh Ba") et ae So009 ri O19 9190 | iS ° 5 |eooraasvaeseens lon CORIO Q | CRO NH oD NN cD GI OD OD OD OD OD it~ oo OMmOOo -O | H = RO leila. | ODFO 2: x uae 8 DoOrnepressmae er dam Meo own ‘o) Pe MMi WHHOO = T “ I 2 AADWAOwWwWAL OIE COMA | Or rt ce SO as ae ne an |: Greta ss RM a re ap 785 cso oe se ne eeuee 1 2 : NANA ANRANRANRHRNAN I] RG SC) See - => A cae ES ja ; Sx | oe. Ses B | SCCweODNOMPHANTODN | HO - | wot © 8 =} ANRENANFRNANRANAH ION => ole ao ae iS Le E> aa) S a DO | =, eae ° is) eo a S POPLPHBMONADABDBANDOMW |! On S Fow ds oy 3 AMNAHNNANARANNHAHAI]ON Ry Seno < : =e a) oc) ae e 2 aS oe| x ‘Gas o> 2 ae = 2 es BE | MIOAMMOODNDMNHMONOS | HON P Ron Ho, Sa me at = = SS 7 4 ° e e SS = = he a ee ee er Ore > Be) se) ME VE OE a Ss a) Lal ~ ae S S D | = shag : me 3 APOMAANNOHAROOAA O i x mo 10 es = 5 ES eee ee ee ee in a MOO itt 2 S Ee =< . Fy Be | SOA Owns tormtoiao | O16 SS 18 = —oe | a" Gade) eee Ss N a EB | Pr PH OH oenNoonw sy | HO Pro & | eee eee eee eee 1 oe Sere < |x a | my SWOMEDAWMAANWPAEN | On co oO OO — oe Cc “8 DOOD OEE ERAOHOMOW | Or hod se ee ONAN sss g SSE SIS Sr NOS Ele (ERM Cone oo ite aad nN mocne = = oO nN 5 DOANMDAMOOKRDROHAM! } BS Se ine en one ete te te Fan ate a io ees o90000 = eos Jaa | | oneeur 314 Mr. R. H. Scott. The Variability of the [Mar. 27, 2 DP DD Oo G2 Oe . 4 COM GHA BR | ROHNMHMWORDAOHAM 3 arn S | SEE REEEEEehDDHD Ss | teat | aan a | 1s oS909 OnwWoOwWwo —S 2 a s | ¥eouwenwnnngann on 419 6 0 SRE cs a oo ©OOImo 3: eae IDO NO NOLPWAHOHAWH | AD HOON Gn i ied an hos: ues DOr EAD MHANDOHNMDO | OD A oD ee aie ae on OONHS 3? = — 2 | woo wnsonovevene Aes Oonkn a Mic | wOno:: we | COP ODHOHHMONONMO | OO HOOD ._ => NANAANANRANKRARA AION Sioraiiao = rs 8 | ke ae o = SS & us Se bE | COD DDOAHEEADBOHMMH | ON -| Bade loon} ° Se = MAHNAMHANRHARHARA IAN Srila erica ieaies at. c SS F> on = ie : | = =a i= = Aw S | FOWOHOCSW OEE MEE W [wa | | Ag =) = NNANNANANANAHRARAN | ON Ry Canoes We PE = —_ oO paar i) eo G4 i HS Rh Bm | SOHADDSOWOANAMNODAWO | WN SOS ah oe a MONO: -: a J onwoeennoavanan lon Ona on) MANNANANR AAR ANANH [ON Mace = : 4 = a ee Pee ae. | epee s dies eu) maco . : = 2 [ene voonsoveerss | on ONod o NAMMANMANNAMAHANNA ION OMmMAO : : Fy | = pa Pe eee Oe ie T= 10.29 63 Al ee a ee ee 19 Gs aes s ~~ re e .J DP DD DO ° Sea 0D HO HO aI DOKBNAMANMORDROBANM ss nin ® ORR RERRRRREKAODOGD] ag Lae a He “2les 5O0900 = - > S | ne °O 190109 1890.] Temperature of the British Isles, 1869—1883. - 31d . | a COHORT BS 1LROTHNAMYWMOKRDHROnAD! §F§ re eal S | SS REE eNeeenavnog ok Oe a = pa 10 SPeeee a POH wWOMmO Ane Sas , 1 a NM WD OOAGHH EN DWN AD | 1090 Omron a DOANMDAOANHDATUANADA | OO Oe - a a 2 [paecansonasncas No OCCT eo) : ete eS 2 Se woos 2: a Dr~OSCOMKnRHAAHOROKNMD |] HH |. 1 6D I~ 10 3 eS eS SSCS So ESS Sie se Fgh dik ro) DDO MDHNAUNNAMNAMMNANN 1 OM COI = « ; or l 2 [ans oyanrovonaos low 9. Ol alee nase ITE 1D A eres) OE mM oD a i] tio Ba FE BP es en) -o x PO . = MANNANNHNANHAHAHAIAN EON Gc. ae SC = /@ nN D = ie 2s = 5 | s$enmosoynreages HO S| aon = SPC SO ROS QUE OS CV GI}COV'E Shs S Sy ol eae 5 5 MNAHMANANANNR AHMAR | TN Ss WRDMDO . - Ss = a) is = qt ~ | s ot a 2 BR || ¢ |reeaseagenannae [ae | S|] ead we a NAMHNNNANNANHANHS | 10N core, ey = — a > ise) es. fo) as 5 lesonmavouncaene 00 10 Conese SF [AMMAN ATAAAAN AA oa moro: : ® | | TH | MOT MEAHMHRMOMONOS | od | monn | BMI nmnarnannnannansion Dies os S a 8US 2 25 3 : 74, - 20 10 : 75 1 22 v4 ats ‘ 76 Vi 18 5 ‘ 77 7 248) i 3 78 2 20 8 ‘ 79 x 11 19 on 4 80 Bi 29 1 81 10 18 2 82 2 26 2 1883 1 28 1 Sums 53 338 59 May 1869 1 28 Z bie 70 a 11 20 Tal 14 12 5 72, 23 8 8 2 18 11 aie 74, 22 9 75 he 6 25 a 76 Nr 14, a % Wh, 2 20 9 , 78 a 12 19 79 be 28 3 80 ate 18 13 ‘ 81 aug 15 13 3 82 ; me 14 17 1883 1 14 16 Sums ae ube 6 257 194, Bis, ¢ 1890.] Temperature of the British Isles, 1869—1883. ddl Table [V—continued. GLAsGow—continued. June. Year. | 10—19°9.| 20—31 °9. 32—39 9. 40—49 °9.| 5|0—59 °9.| 6(0—69 °9.; 70—79 °9.) 1869 bie aie ve 6 20 4 Je 70 are ne ee 2 24, 4 ie Ph AG : 50 2 Psy ot § AG An 72 ee aia 4 22 A - 73 ee ee ee ee 29 1 ee 74, ke me a ea 30 ie ie 75 ae a ace a 30 wae : "6 ee ee ee ee DA 6 ee Th si at a 1 29 ae ia 78 x é 5 2 21 5 2 79 sha Sides is 5 25 be é 80 ais Me ite 5 23 2 we 81 Ac sen} : 5 23 2 ale 82 ea . 3 26 1 , 1883 ve oe 1 28 i 5 Sums ‘ ‘ 36 382 30 2 July 1869 eta A 17 14 a 70 ae 5 19 10 2 71 aie 27 4, eve 72 Ae Ae ‘ 16 15 we 73 ‘ ; s 27 3 1 74, ave : 21 10 We 15 are : 25 6 ale 76 Se a 25 6 ris 77 - 30 1 de 78 aie 6 18 13 ee 79 ie i 29 2 ie 80 Se : 27 A, i 81 ie 30 i Fr 82 we ‘ 27 4 ie 1883 oe 5 26 5 332 Mr. R. H. Scott. The Variability of the [Mar. 27, Table IV—continued GLascow—continued, August. Year. | 10—19°9.| 20—31°-9.| 3239 -9.| 40—49 *9.| 50—59°9.| 6069 °9.| 7079-9. 1869 sis ate ale 2 23 6 cs 70 ae 2 ere 1 16 14 ze 71 54 ‘ as AG PAL 10 fe 72 wa 50 ne ele 29 2 ae 73 aie ov ie 56 30 1 es 74, A ee ea ae 29 2 es EB es ‘ nV ais 26 5 ote 76 ‘8 SG 4 Bie 22 9 a We Aah ee oe 2 25 4, es 78 ae E mi as 24 i oa 79 $i B SG 1 27 3 xe 80 5 ite ‘ bi iS y 13 6 81 ; 5 A, 26 1 ste 82 y . Bt 26 5 ei 1883 é ‘ F 31 aye ‘ Sums 10 373 82 September. 1869 Sa AG is 4, 25 1 ix 70 5 : se 2 28 na ri 71 ai ‘ sie 12 18 ae ans 72 ae ‘ Et 12 18 i a 73 At ats és 9 21 a aie 74, 5 ‘ Ae 6 24 ate aa 75 e ee ee 5 23 2 ee 76 : Bs bs ih 23 #4 ne Teg ‘; ais a 13 uz se : 78 ‘ bie é 8 19 3 bad 79 or ae 8 22 ite ie 80 ; is x 3 24 3. os 81 avs ° 1 29 a as 82 ac A Y 23 Li Re 1883 te , 3 27 we e 1890.] Temperature of the British Isles, 186S—-1883. 333 Table [V—continued. GLAasgcow—continued. October. Year. | 10—19 -9.} 20—31 ‘9.| 32—39 :9.) 40—49 a 50—59 °9.) 6(0—69 °9.| 70—79 ‘9. | 1869 ae es 6 11 13 ni es 70 aé ea ae 27 4, a : 71 ee 2 19 10 ae és 72 24 ma 2 26 3 ae ae 73 ee ae 5 21 5 ee ‘ 74, : oe 1 26 A, a 75 . a 1 23 r x 76 ne “ i! 14 16 Me af 77 ae da 2 18 ae! ze a 78 de od 2 11 18 ie ae 79 “F ae 4 22 5 eo a3 80 “ aa 9 20 2 5% eg 81 P 5 19 fi se ke 82 eH “ 2 14 15 ea 1883 5 EAE ad 25 6 By : Sums be : 42 296 126 i. ae November. 1869 oa 4, 11 aig | 4, #3 é 70 ae ds 18 11 te 4B . 71 3 1 17 12 pe avg F 72 ee a 10 EF 3 as AG 73 zt 2 vi 20 1 ef es 74 -- as 10 16 4. as a 75 aS 2 17 8 3 é ou 76 a 5 ME 12 2 rg ry! ae <6 8 21 1 3% 78 sk 3% 18 12 Be es 3 79 a 2 gf 16 1 F zi 80 e 6 8 15 1 , ay 81 Sty a5 3 21 6 ws ie 82 ee ks 20 10 e ies 3 1883 ba 2 14 12 2 2 334 Mr. R. H. Scott. The Variability of the [Mar. 27, Table [V—continued. GLAscow—conténued. December. (o) (o) ) (0) fo} ° fo} fo) fo} to} (e) ° ie) oO Year. | 10—i9 °9.| 20—381 °9.| 32—39 :9.| 40—49-9.} 5|0—59 ri 60— 69 °9.| 70—79 °9. 1869 ‘ 8 16 4 ofa aie sic 70 2 vf 17 5 ss ee A 71 ne 3 14 14 & ate nic ae ate 3 15 13 oie ake e6 13 , ste i 24 ae wie Ae 74, 1 14 14 2 ats ae es 16D ve 4, 7 20 ane se va 76 % 1 8 22 as fe a CE Ae 2 9 20 ‘ ae 6a 18 1 14 14 2 ‘i ‘ ne 79 1 8 11 11 ab aie 80 are 5 13 12 1 “% 81 2 -16 13 P é A 82 ats 11 11 9 : ate 5 1883 11 20 ° ae Sums 5 93 192 174 1 he ee ABERDEEN. January. 1869 are ais 11 20 ale ne we 70 we 1 24, 6 we ets ee 7A A 7 22 2 AG aa oe G2, Ae BA 15 16 ao aie Y 73 ve ai 15 16 o* ste é 74, 50 ave 12 19 et ate ite 75 aie 2 12 17 eis ai Se 76 5 9 17 eae ae or Me ile 2 19 10 ave se ee 78 ie 3 20 8 aie aie wa 79 ate 10 20 1 AG ae Re 80 we 2 18 11 oe exe ; 81 1 20 8 2 Ae re 82 ae Ate 11 20 ui me se 1883 o's zé 19 12 e SC a — — = | Cf Sums 1 52 235 177 3 ae 1890.] Temperature of the British Isles, 1869—1883. 335 Table [V—continued. ABERDEEN—continued. February. Year. | 10—19°9.| 20—31 *9.| 32—39 -9.| 40—49 *9.) 50—59 ‘9. 1869 ee 1 9 16 2 70 a fi 14 7 ea TL ‘ ve 10 17 1 72 . ee 9 20 ee 73 ° 5 19 dh: 74 1 13 14 75 2 20 6 76 3 22 + 77 3 13 12 78 a oe 10 18 79 ee 6 19 3 80 es ee 7 22 81 3 24: 1 82 ° 2 9 17 1883 es ee 7 21 Sums : 33 205 182 3 70—79°9. 60—69 9. ear fs *) ia 336 Mr. R. H. Scott. The Variability of the [Mar. 27, Table IV —continued. ABERDEEN—continued. April. [. |-lo lobe lel « DI a Le | ‘Year. | 10—19°9.| 20—31°9,| 3239 -9,| 40—49-9.| 5059-9. 6069-9. 7079-9. jo as | | / lial a.) (8 | 58t| (25@) |) nn 1869] .. ie 5 15 10 af 0) ee i 2 25 3 ie ae ae 4 ia 19 : oe eet ea ie 7 18 5 MBs. ie is 3 26 1 S| 74, ee ee - ee 25 5 ee 75 55 ener 1 25 4, 7Oltee a i 7 20 3 . if en oe in 12 18 ‘ a i led oe i 5 22 3 ie Bi oo ne 18 12 x if es 30) |. is ea 28 1 ca oe x 15 15 af eo of. 1 7 20 2 1868 oe & 30 - Ee Snms ba 1 94 318 37 = May. 1869 1 29 1 70 1 13 17 7 1 16 14 7 72 iS 23 8 Wa he, 2 26 3° no Pan OV on 1 25 5 be a Wel Vis. Bs A 15 15S 1 a vale 1 22 8 ee 77 5 24. 2° 3 78 é . 20 1 > 79 4 25 2 | |. ‘ i 20 u - Bie. eo 1 15 15 82 r 24, 7 1883 “ 3 17 10 1 Sums ee ee 20 314 129 2 ie a 1890.] Temperature of the British Isles, 1869 1883 Sot Table [V—continued- ABERDEEN—continued. June. ° ° ° ° ° ° | ° ° ° ° ° ° ° ° Year. | 10O—19°9.) 20—31 -9.| 32—39 5 40—49 °9.| 50 —59-9.| 6(0—69°9.| 70—79 °9. | | 1869 i. Ac ws 10 18 2 sf 70 ae 3 24 3 71 ae a : 15 Lae we ms 72 e és ae 2 27 1 7 73 a Ac Ac Ae 28 2 , 74, aie : 4, 25 1 > 75 : ‘ 2 27 1 : 76 es , 2 27 1 77 ™ ee ee e 4, 26 ec 78 Ae . es 12 13 5 79 aie - 15 15 Pie 80 ie ae a 6 23 1 81 mop - 13 1% ae 82 we ‘ ae 8 22 ne 1883 2 = ual 18 1 Sums ES ee : 107 325 18 a ! July. 1869 ae ae a re 22 git”, ae 70 ee oe ee ° 22, 9 ee 71 ie oe oa aie 26 5 An 72 as i és ie 23 Sic nye 73 a = ae 26 5 Os 74, ee 3 . ce 21 °° 10° aie 75 aa ‘ : i 29 1 a4 76 Sta Be oe are 25 6 ate 77 hs te Pe i 27 3 § 78 Ris ‘ ze ao 26 4° 1 79 ac = F 1 30° enn ays 80 ai te oe wee 81 Ns a 81 ne - : ib 25 5 ate 82 oa ; 29 2 ae 1883 ve ae 27 4 ree —— Sums ed we se 1 A 389 7/8 Vee 1, 338 Mr. R. H. Scott. The Variability of the [Mar. 27, Table LV —continued. ABERDEEN—continued. August. Year. | 1O—19 °9.| 20—31 °9.| 32—39 -9.| 40—49 °9. 1869 oe : i 70 ° oe 1 al : : a ae 72 : ee a4 73 ve . iL 74 300 a oe 1 m5 ee ee ee oo 76 oe ae “4 2 77 ee 3 78 ie Tf) 1 80 : ae 81 , 5 82 ve E ° ae 1883 ae : Sums ee ve oe 15 September. | 1869 a5 4, 70 ete 2 71 : 56 ee 14 72 oe ee 13 73 ee ee 9 74 ae 5 6 15 e ee 7 6 76 11 77 ee ac 16 78 oe 20 79 ole 6 80 . ee . 2 81 : 4, 82 . ° 6 1883 7 Sums oe 126 50—59°9. 26 25 21 30 [e) 60—69 °9. : NON? wr NEBNHHOUD ISS ~J te} ie) ° 70—79 °9. 1890.] Temperature of the British Isles, 1869—1883. 339 Table [V—continued. ABERDEEN—continued. October. Year| 10—19-9.| 20—31 -9.| 3239 9. 4049 -9.| 50 39 -9.| 6069 9. 70—79'°9. 1869 bs he 7 13 10 1 t 70 a3 if a 21 LOWE Fale, at 71 re 12 19 i. ie 72 1 25 5 ce ee "3 5 23 3 ifs yf 74, ; 1 25 5 a ne "5 a 1 24, 6 2 3 76 mi 2 15 14, : "7 a 6 16 9 : : 18 : 2 11 18 bs : 79 : ; 4 23 A : 80 10 19 2 : 81 5 20 6 ' 82 : ne 1 12 18 1883 me - 25 6 Sums ts ay 45 284 135 I ay November. 1869 Ls 3 15 9 3 a | 70 : Hi 18 12 a iS i 71 s 19 11 3 72 s i 8 20 2 ; 73 is: ee 8 22 74, if 14 16 "5, 1 17 ll 1 3 76 1 9 20 | ri ‘ oe 10 19 a A 78 18 12 a | 79 1 12 17 es 80 f 4 10 16 d e a 81 3 23 4 : ‘ 82 : 17 13 ne of h 1883 ad 16 12 2 es iF | Sums ae 10 194. 233 13 tes | VOL. XLVII. 26 340 Mr. R. H. Scott. Zhe Variability of the [Mar. 27, Table [V—continued. ABERDEEN—continued. December. | Year. | 10—19°9.| 20—81°9.|32—89°9. 40—49 °9,| 50—59°9.| 60—69°9.| 71 199) 1869 ee 6 19 6 ee ee ee 70 te 10 16 5 Me he ace 71 ee 3 17 11 a ' 72, a0 3 12 16 mt 73 a es Tet 20 = 74, ie 12 18 1 | "5 a 5 16 15 76 a Ns 12 19 x ue ai we A 13 14 oa a = 78 ta 18 11 2 ve ae ae 79 i 10 13 8 ie a 80 iL 8 13 9 a i, 81 , A -15 12 ay fe zh, 82 2 6 14 9 ee ee ee | 1883 ie 1 20 10 se | Some 3 85 220 157 a: R FALMOUTH. January. | 1869 : se oe 24 7 70 : ie 8 21 2 val 1 16 14 fe : , 72 he os 27 4 ap "3 ee A BS A, ee ee TA, e ee ee o7 4, 15 ‘ re ee 18 13 "6 | ; 2 9 19 1 i Wh e ee ee 25 6 ee 78 ; ie 5 24 2 ot 7 79 ‘ 5 12 14 Ae aw op 80 E 14 13 17 1 81 8 10 13 Ly 82 Po ny 2 24 5 | 1883 Me sh 26 5 ‘Sums 16 79 316 54. nf : 1890.) Temperature of the British Isles, 1869—1883. o41 Table [V—continued. FaLtmouta—continued. February. | | | | Year. | 10—19°9, 2031-9. 323) 9, 40—49 9. 5059-9.) 60699] 70—79°9. | | 4 1869 oe | ars 17 fi: & 70 4 8 16 “a ae Tt & 1 23 4. 72 “ ws 25 4 73 F 11 gr aac Ac 74 | 1 27 - 75 i» 8 17 2 ‘ 76 6 By, 6 3 77 ae 1 18 9 é 78 2 23 3 t 79 “a 9 18 i é 80 = ire 27 2 os 81 8 18 2 F 3 82 ate ere 24. A 4 1883 P 28 eA A Sums | 5 | 55 | 315 48 ‘ March. 1869 Py Le vi 24, as ots 70 We ws 6 22 3 - fps 0 ‘xs Pi 28 3 ae 72 ae 5 14 12 ats ao arg A 3 27 af Be 74. Ae 3: 25 3 é 75 ote sec 4 25 2 - Be 76 ot 8 21 2 3 77 5 # 3 25 3 A 5 78 g 2 4 23 A. , : 79 a P 6 24. 1 i 80 at és 28 3 : 81 #2 2 25 A, ed 82 oe ae 25 6 we 1883 ae 17 14 re Bic Sums Es 68 350 47 : } 262 342 Mr. R. H. Scott. The Variability of the [Mar. 27, - Table [V—continued. FaLtmouta—continued. April. (9) fe} fo} [e) Cc oO fe} fe} fo} fe) ° fe) Year. |10—19-9.| 20—31 '9./ 32—39-9.| 40—49 -9.| 50—59-9.| 60—69 -9.| 70 —79 -9 1869 me a re 11 19 se ; 70 ee ee ee 21 9 ee s 71 eS : Ke 13 17 : : 72 ] es: 20 10 ; : 73 uy 20 10 j a 14, = ne 14 16 ees ‘s #65) HS 23 7 oe HY "6 ah a 1 20 9 : mw. 4 77 s ra ¥ 23 7 gee | 78 ‘al 2 19 11 ‘ 79 ae 4 25 if ; as | 80 Me v4 ‘ 23 q 8] ie 3 23 4 ; , 82 } x 18 12 ; 1883 28 2 ae Sums i 8 301 141 ae May. 1869 ; a a 8 23 2 , 70 Me ; a 8 23 ‘ % val j : 8 21 2 72 5 : 16 15 ae 73 s. 10 21 se 74, ‘ ; 10 21 ws "5 &: i a 30 1 76 rm is 13 18 4 "7 * 13 18 ; 78 ue : oe 31 a 79 ie * : 15 16 x 80 ne ; 7 23 1 81 i a 5 24 2 | gg ve Re at A 27 « 1883]. a 3 fel 20 3 | Veiawas 6: i oe 128 331 6 1890.] Temperature of the British Isles, 1869—1883. 343 Table [V—continued. FaLtmoutH—continued. June. Year. | 10—19°9.| 20—31 -9.| 32—39°9.| 4049 -9.| 50—59°°9.| 60—69 -9.| 7079 °9.| 1869 Ae a ae oe 26 A. Be | 70 a5 a Be. oe 23 74 2 71 - Ae 29 1 x 72 at ie 27 3 5 73 x 2 22 8 : 74, ‘ ae Ss 26 A, c 75 Awe ee 28 2 if e 76 aia Sia 23 vi ‘ 77 ee ‘ 17 13 = 78 ba 22 8 ‘ 79 ne 30 a : 80 are ae Ar ae 27 3 81 ee ee ee 1 25 A. 82 ee : shy 30 re 1883 27 3 Sums Z 1 382 67 July. 1869 ‘: . vi 24 : 70 sie f 2 29 val 21 10 72 7 24, 73 a 12 19 94, 9 22 v5) Be ne we are 22 9 76 Lae si as a 6 25 77 a we ae Ne 20 11 a 78 se ee ee ee ~ 6 25 ee 79 ; ae 28 3 aie 80 as 14, 17 81 ee ee 12 19 82 a i 24 y 1883 F 27 4 a d44 Mr. R. H. Scott. The Variability of the [Mar. 27, Table 1V—continued. FaLmMoutH—continued. August. | | (o) \ (e) (e) fo} {o) fo} oO | oe to—19°9. a) 40—49 9 | 50—59 -9.| 60—69 -9.| 70—79 - | 1869 i fe re 13 18 Ser 70 “ Ns fe AY 9 22 ne ral = a se fe 6 24 1 G2 ee a ie o 14 7 oe "3 fe * i 2 13 18 ab 74, a hi ” Ls 17 ‘tA . 75 s Me i ih 6 25 a 76 ¥ A ie ie 10 21 Be Ta De Be ie a 14 17 78 a ine % a 1 30 iby 79 . om x e 26 5 ie 80 i a es Py 2 29 uf 81 Len is ai ¥ 24 7 8 82 a By A Li 18 13 its 1883 a oe a By 16 15 ne Sums Bi Bie is Se 189 275 1 September. | 1869 he i. 24 6 a | 470 E . 4 Ei 25 5 a vat E. i 20 9 ‘ 72, : 3 13 14 73 a 28 2 £ 74, 26 4 €! | a5 9 21 iN 76 2 3 sid "7 i. 1 28 1 a: 48 ! 16 14 : 79 30 x ‘ 80 : 20 10 , 81 ee 29 1 e 82 29 1 : | 1883 27 3 3 | Sums 5 351 94. 1890.] Temperature of the British Isles, 1869—1883. 345, Table IV—continued. FaLtmMoutu—continued. October. ° oO Oo ° oO eo) fe) Oo fo} fo) fo) (oe) to} (eo) Year. | 1O—19 °9.| 20—31 -9., 32—39 -9.) 40—49 :9.| 50—59 -9.| GO—69 °9.| 70—79 °9. 1869 ER 10 20 iL 70 4 5 26 % & 71 1 30 72 ae ae 15 16 73 Ze 12 19 ‘ 74 ‘ 2 29 75 i 6 24 1 76 Fie 4, 27 77 ia 3 28 78 F ae 8 ZI 2 79 A we a 5 26 ats 80 : Pe 15 16 81 P if 9 21 5 82 ae 7 24. 1883 hs 4 4. 27 Sums ES 1 106 354 4. ‘ November. 1869 o y 16 13 wre bes 70 . 3 20 v6 ee Ee yi 3 4. 21 5 He ee 72 ee te 1 20 9 5x 73 Ke a ig 23 f “ie 74. Si = a 12 18 Aes 75 ue 6 Pe 13 76 1 13 16 77 ag 16 14 ‘ 78 2 27 79 ‘ 8 17 5 : 80 - 3 15 11 sits 81 ie 8 22 s 82 1 21 8 2 1883 a8 22 8 346 Mr. R. H. Scott. The Variability of the [Mar. 27, Table IV—continued. FaLmMoutH—continued. December. fo) fe) fo) oO (o} fo) fe) oO [o) fe) ° ° fo} Year. | 10—19°9.| 20—31°-9.| 32-39 -9.| 4049-9 | 5059 9.|60—69 -9.| 70—79°9. 1869 ate 2 8 19 2 % ore 70 “ee 5) 11 13 2 : ot Ta. A ae 9 22 “ie A aS 72 ae 1 24 6 : ; 73 Se ate 28 3 ; $ 74, AS 10 21 ae - : D 1 9 18 3 : : 76 3 16 12 A 4 hve . sie 28 3 . ae 78 2 17 10 2 : re 79 : 10 20 1 : F 80 2 14 15 : 3 81 3 i 24, 2 ; 5 82 Ne vf 16 8 : J 1883 ia 4 24 3 Ie Sums 10 96 297 62 ae STONYHURST. January. 1869 <% af 7 23 oe New ay 70 ete 5 14 12 se ae ral ‘ 16 13 2 aye (2 ss we 12 19 : 73 4. 10 16 i - - 74 : xs 9 22 15 1 6 23 1 76 se 4, 12 15 : ; Md ‘ ats 11, 19 3 78 1 14 15 uf 5 79 . 23 7 i é : 80 4 13 10 “f i Ne 81 4 15 7 5 : ne 82 Ae 8 23 ae 1883 1 19 10 af i 1890.) Temperature of the British Isles, 1869—1883. 347, Table 1V—continued. STONYHURST—continued. February. ° (0) ° ° ce) fe) a ° Oo O° fo) oO fe) ° Year. | 10—19 -9.) 20—31 °9.) 32—39 -9.| 40—49 . 50—59 °9.| 60—69 °9.| 70—79 °9. | 1869 ee A 5 21 2 7 70 es 4 13 8 wa i ae 71 ee 2 6 20 ee i ee ae ie ‘ “ie 3 26 a cn 73 5 23 Be ae F ‘ 74. ie 7 Fi 14 ae Bee ze 75 3 18 fi oe Be aye 76 3 11 15 ee i eo ee Ma 2 if 19 78 aie 1 12 14 } a P 79 ee ne 5 18 5 ee 80 we ae 9 20 gs ‘ 81 sia Se’ 21 4, : 82 ae ee 7 21 si F 1883 ae Me 10 18 ‘ Sums ‘ 38 170 , 212 3 oa March 1869 re ~ 23 8 F ate ¢ 70 bi 16 15 Pr Ti Ne 8 18 5 i ye re 1 T 19 A ae ve ee 18 13 a ate 74, es 2 4, 25 : iss q3 Se av 14 aan ans 76 pad i 18 12 ‘ ie 717 ‘ 1 16 14 Ps ne he 78 i 14 16 ss ? 3 7 A 10 17. ae oe ‘ 80 ee 11 20 ae = of 81 aig 3 13 15 : bra ‘ 82 eed Aa 4, 25 2 ee xe 1883 ae 6 20 5 0 aie 348 Mr. R. H. Scott. The Variability of the [Mar. 27, Table 1V—continued. StTonyHURST—continued. April. fo} fo) fe) 0) fo) (e) (o) (o) (e) fe) (o) ° o Oo ¥ ear. | 1O—19°9.| 20—381 °9,| 32—39 ‘9.| 40—49 -9.| 50—59 -9.| 6(O—69 -9.| 70—79 9. 1869 i | i 19 8 2 J 70 ae is 26 4, ihe 2 71 ‘ 2 25 3 sls ‘ 72 ‘ : 3 22 5 se ‘ 73 4 22 A Pcs ! 74 ; aN 19 19 1 2 75 wid 21 9 Br F 76 4 21 5 ‘ 2 Ga 3 27 a F 4 78 4, 18 8 2 719 12 18 Be : 80 be 28 2 ce, 81 10 18 Lee ee 82 ia 1 25 4 i 1883 1 29 se Sums 45 338 64: 3 May. 1869 1 28 2 , 70 ais int 20 Fi j ui 13 16 2 72 ety 22 9 73 & 20 ka TA ee ee 19 12 ee 75 ; ae 23 8 ee 76 as be 19 12 Wh é 3 21 ef 78 ste dite 8 23 aie 79 3 19 9 ‘ 80 ‘ hs 19 12 , 81 we 11 15 5 82 é ae 13 18 : 1883 1 13 LWA as Sums 8 259 191 a 1890.] Temperature of the British Isles, 1869—1883. 349 Table [V—continued. StTonyHuURST—continued. June. Year. | 10—19 9, 20—81°9.| 3239 °9.| 4049 -9.| 50—59°9, 60—69-9.| 70—79 9. 1869; .. aa 2 2 24 4 £ mf. He i x 23 7 i =e. # i 6 21 3 - a. K: 2 19 9 F RS ee a3 a 26 4 # 74 as “s a aa 29 il a oe. is ib 27 3 i ‘el as oh ‘ 24 6 a 77 oe ee ne es 23 a ee — " F: 1 22 5 2 a... 4 x 4 26 a é ae i f: 4 22 4 ie ¥ : 5 21 4 ae 3 26 He 1883 i 1 26 3 Sums de ee ee 28 359 61 2 July. 1869]. us i 12 18 1 mr (2. ie 14 17 71 s 27 4 72 if 12 18 1 73 i ts 18 11 2 74 $3 16 15 Wail o's. . 19 12 76 33 3 i 18 2 77 4 Ma 28 3 er i tt 12 2 79 : bs 28 3 . 80 Bs 27 4 E 81 sh # 22 9 82 i ia 26 5 1883 = st 1 24 6 # Sums}. 1 301 155 8 300 Year. Mr. R. H. Scott. The Variability of the [Mar. 27, Table [1V—continued. STONYHURST—continued. August. 10—19°9.| 20——-81°°9,| 32-39 °9.| 4049 -9.] 50 —59-9.| 6069-9. - u: a 2 22 ae a ag is 17 Ft fe . 1 it zs a 22 oo Sy an 23 Be ae a bs 27 a 32 - i, as ig Be Se ih 16 a ig - - 20 G i vy 17 ee ee ee Q7 ¥ x rr 16 i “ im % 29 a ¥ ei a 23 eo ee ee ee 7 3 312 September. a ; i 25 : 1 29 ; k a 12 17 5 9 13 ie 6 2A i “ 1 28 : : a ee : 3 26 ; 9 21 a ; 5 20 : 5 25 ie : 1 23 : Pi 30 a 24 1 28 oe oe 5. 59 356 70—79°9. 1890.] Lemperature of the British Isles, 1869—1883. 351 Table [IV—continued. _STONYHURST—continued. October. Year. | 10—19-9.| 20—31 °9.| 32—39 -9.| 40—49 -9.| 50—39 -9.| 60—69 °9.| 70—79 9. 1869 es a 4, 11 14 2 ' 70 vi ay us 24. mee ae a 71 a its a ag 22 9 x 72 ie ae ai 26 5 ete F 73 we at 6 16 8 1 74, he Po a 21 10 ate 75 . ee ee 21 10 ee . ee 76 ate aa 1 13 16 1 se ee . ue 2 22 vi a : 78 : axe 1 11 La 2 a 79 wie te 2 21 8 aie ac 80 16 20 1 sie ie 81 ee ee 5 22 4, ee ee 82 56 aia af Lp 14 ae BA 1883 ite Me 1 19 11 A ; Sums - iri 82 264 154 15 en | November. 1869 es 1 10 15 4, aia se 70 as 15 15 ate sts i 71 ea 2 18 10 ; we ae 72 aia 5 9 18 3 ae a3 Pr 8 21 1 a 40 74, 11 14 5 ie 35 75 se 16 10 4 a a 76 BY 12 15 3 oe se 1% a A, 24. 2 re He 78 ‘ 2 22 6 seus at aa 79 aie 2 15 12 1 Br Oe 80 ae 3 12 14 1 ole AA 81 ue ae 3 18 9 aie Pee 82 ‘ a 15 13 2 ihe ae 1883 7h 22 1 rota ; Ss ia 10 177 2277 36 302 Mr. R. H. Scott. The Variability of the [Mar. 27, Table [V—continued. _STONYHURST—continued. December. Year. | 10—19 -9.| 20 —31 -9.| 3239 -9.| 4049 -9.| 50-—59-9.| 60 69°9.| 70 —79 A 1869 y 6 18 7 o ks ee 70 13 13 5 er fe. ral 3 12 16 3 eA ms 73 Q 3 12 16 A ea 73 2 6 28 se be oy 74, 1 15 iBT 4 i. ey 2 75 3 11 17 “ a ) "6 2 5 24 ce 7 1 8 22 i oe ' 78 1 17 11 2 be af . 79 12 14. 5 2 . “ 80 ; 2 15 14 bs Bee oe) 81 f 4 15 12 i A Me | 82 7 13 11 “ i 53 1883 , 1 13 17 mi ee yay Sums 2 91 1 Ware 195 Kew. January. 1869 us 2 6 22 if a GR | Ones 5 1 15 #: ie ba | 71 f 10 19 2 B i oy 72 is ua "7 2A A iS Meee "3 im i 12 16 3 i 74, iG ae 9 21 1 : be "5 i 1 4 24 2 : , 76 y ” 14 9 1 F 77 ‘ 10 20 1 : 78 if 1 15 13 2 : | 79 i 16 12 3 s 80 11 17 2 1 ‘ ' 81 2 12 11 6 a t 82 1 10 20 : 1883 12 18 1 ‘ ‘ ene 2 66 169 215 13 oi ae 1890.) Zemperature of the British Isles, 1869—1883. 353 10—19°9. Year. 78 am 79 ee ‘Table [IV—continued. Kew—continued. February. (o) ° ie) ° Oo fe) fe) fo) fe) Lo} (e} Cc 20—381 °9.) 32—39 -9.} 40—49 :9.| 50 —59 °9.| 6(0—69 -9.| 70—79 °9. ale 2 20 6 ate TT re 9 1 fe ar 1 3 23 1 ie neh 1 26 2 ate als 4, 20 4 5 nic we 5 9 14, a2 ate 5 19 4, a , 4, 8 13 4 ae P 1 A, 20 3 : 1 9 16 2 as ee “ 14 10 1 ag 1 10 17 1 : 1 19 8 ee e ty 9 16 3 a 5 23 ae 33 143 223 24. A March. 2 21 10 ae 3 Bic 1 17 9 4, 4 - 3 5 21 5 Bs He ‘ 9 14, 8 a A 9 21 1 : : 2 3 20 6 i 16 1 2 ‘ , 1 12 16 2 ; 15 16 ae : 14 13 A. avs ‘ il 11 19 ue A, 23 4, i 1 12 13 5 ais 3 23 5 ve 4, 21 6 ad ye do4 Year. Mr. R. H. Scott. The Variability of the [Mar. 27, ° ° 10—19"9- 90—31°9. Table IV—continued. KEw—continued. ° ° 32—39 ‘9. April. 12 15 15 17 19 15 23 14 24, 15 24 19 15 23 21 May. 40—49°9. 50—59°9. 60—69°9. 10—7 9 . 9. ¢ 1890.] | Yemperature of the British Isles, 1869—1883. By) Table [V—continued. Krew—continued. June. Year. | 10—19°9.| 2031 -9.| 3239-9.) 40—49 °9.| 50—59 -9.| 60—69-9.| 70—79 9. [ 1869 if Zn aa x 25 E is 70 sie eS a iy ee he ae = 2 Ft eas eh ae 4, 20 6 me Ba 72 ee Zi ul w 18 10 2 73 ‘ iA it S 17 13 74 i ne ab 1 19 10 "5 ne y ie fe ie 15 es 76 ws et as iS iz 17 12 1 ae a a re in 19 z 78 te ir if ie 19 6 5 79 ce i aw ae ea 2 5 me 80 a a a 1 ie 13 i 81 - ie a 3 10 17 82 ee ‘ 1 25 4 1883 : é 9 20 1 Sums 7 10 260 169 11 July. 1869 » 5 22 4 70 : i : 5 20 6 ve: 14 17 $e 72 : 5 23 3 "3 i } 5 23 3 74 3 25 3 "5 19 12 ) "6 : 2 24 5 77 “a 11 20 Be 78 - ; 5 24 2 79 : 23 8 i) 80 10 21 re 81 ¥ 8 15 8 82 ; 12 19 at 1883 17 13 t Sars * . ‘i ae es | aval 286 35 WOu, XLVIL 2D 306 Mr. R. H. Scott. The Variability of the [Mar. 27, Table [V—continued. Kew—continued. August. O° co) ° ° te} 12) fo) ° te} ° oO ie) ie) oO Year. | 1O—19 °9.| 20—31 -9.| 32—39 *9.| 40—49 ‘9.| 50—59 -9.| 6(0—69 -9.| 70—79 9. 1869 oe ee ee oe 15 14 2 70 ee ee ee ee 13 18 ee 71 +. se - oe 3 26 2 72 oe of ee ee 13 18 E hen se S eo 8 23 ; 74. =e oe # ee 15 16 : ieee 39 a5 es ee 9 21 1 76 ee ee ee 4 19 5 tl : ae ° 10 20 1 78 oe ee : . 4 27 ee ye “- oe : : 16 15 oe 80 . ee . . 4 27 ee 81 ee : ve 20 11 oe 82 : oe 18 13 ee | 1883 : ee 10 21 . | Sp (eer ene ARES eee Se pie na Sums . 2 165 289 11 September. 1869 oe oe . 18 12 ee 70 ° oe i 25 4 ee ae ee 3 16 13 oe 72 . oe ee 5 11 i 1 73 ee oe 1 27. 2 ee 74 ee ee 22 8 ee 75 a ee ee 13 Erg oe 76 oe -- i 25 4 a ed, ee 9 17 4 ee 78 . - 4, 20 6 ais "9 .Y ee ip 29 ee ee 80 Ls oe a 15 14 81 . ee Ly 27 2 ee | 82 = 3 24 3 be | 1883 ° 1 27 2 ee » iz ~4 Table 1V—continuwed. Krew—continued. Temperature of the British Isles, 1869—1883. 307 Lo 2 October. [o} re) fo) ) ° ° fo} ro) ° fo} ° re) ° Year. | 10—19 -9.| 20—31 -9.| 32—39 -9.| 4o—49 -9.| 5059 -9.| 6(0—69 -9.| 70-79 “9. 1869 “a ae 3 12 14 2 ; 70 ae a i 12 19 oe : 7 a & ae 13 18h e ; 72 - ep 1 21 9 y i 73 cae 1 3 14: 12 1 ‘ 4 74, a a Be. 10» 21 ae As 75 ee ue = 19 1k 1 e 76 ee “ aT 1 14. 5 m me! ss Pe 1 18 11 1 ay Mee os : 2 10 17 2 ba 79 ae . TANGA HO: - eS ons a ee BD b= Ss ro) 2 ororSs.. | Sa als 2 AOD e ere ec 4 Foo == SS ® a =) Ce. aes ua Ge ee ee ou = ae mM nN nm : | = eo MOF NO 4 IX O10 — b> ee . é 2 . e Fee. aie SBE ‘ aes PS fa] = S Sit Heo Woon Be = Pe ions : 2 ae CWS CO = se BONO BIO oS 4 =< ‘ as] cs ot aa 2 2 “ is i CV19 od 2 AHLan = FH Ow [ax] e . — ¥ = te e . ae A ei e eo ~~ © be . & © =H 10°92 e e e ~N CO e pe = < ae o Srey ag o . = as Onmhd 1910 & 2 a 2 .SroceS < 3 Dewey « os GGUS fa. te = < errs x = mn i = aa co 10 NOWO Fo Ho ax} ed a e 7 aes eet ee e es . e NX = ° e e NON ee e~mewww1n Oo e = = nN SS ri ae) =) | a | oho PDE HSS ried S sOm He ss Potolei= Jems ~Aa es « Fy | = se = eo reo Oro» NO Soa a TOWN HS et =a oor." s Ox Oo OS aes Fo ae cod | P2regaae MHRA ERRR PAA PARAH OD HARARAAO AAARWAAD DHAARARWA Poe itt rn | | Seooeoog So GIoooooo Secon e Ss 2S SEs : ~O?¢s : : SGenoooo aQenooes Sono ooo SHANOTHOR SANDS HOR SBANDAHSOR 360 Mr. R. H. Scott. The Variability of the [Mar. BT, 3 ey Se) St mm eoO ras Oodtoii: SOMOaw 2 Steaes 6 2: | = Ss ae > | E> > 29) Oa ene root © Sere cneye Su 3 3 SNE O's oe Ry Zi | rior ees rea 3 | Coir amo monmo> ‘o) 5 Bea coeyeG) s BS 2SiSisca Ss oe Si 1-5 re N ese + | FOLD Seip sac) ry % a A a skoao < 5S de eonee eon Sf immn : ea ap oor ies NOD a SE he sets eOneo) tis Sos Us paren St fcoaoc r4 S a | co 1010 i 0010 3 > ft ftom HO Sh ae te SWeieeRn Ce ae 5, cS Swe FS | a St a rs stealer = a = 2 | mon rt 210 19 z OD mam Ss eZ 3 Shia 5, Mines eel) ae se S) 6) PG oneniine D Sf cH HO == S a ce nN a nN Ss & =) =) Ss a S ae] | i : = ba a | & GRNen Si B Diet a ee > < Ss | = et OSs 1 es oe) 6:00 NS ae ea < oS AS 3 © a eS as} “ Sa rs | rot co QUO Dek brs Swan 2, JO Oma 2: - .O'O co ae sete < —< N B | HD Dr Bel Se) aa a2 oll is | SNHMO 22 2 Soo fe Se COU! a oe ~~ a} | AS al I~ ON xe CN es Aino ete aie Doman. f 4) =) ee = qj | Bo ee eco rc rt SO oOrne = | Sie aoe ee sia iene ie oOnwnoxwto : rst ore | PPAR DPD PADMA D D> HO? D FD ODM HRAAAO AARHRHBAD ADAARBAAaAD elit) (Git) as PSSEPSESS2P PFSESPSSESSO PSSSSSSP COoONoCCoOO CONCS CONCOOO FNM Hid Or aaa teor mA H10 Or ee eR TE RP Table V—continued. Kew. Jan. 0) 1 15° 3° 2 ur 4, 1 60 -0O—F9 °9 70 0—79°9 361 362 Temperature of the British Isles, 1869—1883. [Mar. 27, It seemed of interest to exhibit these figures graphicaily, and Plate 9, illustrating them, has been drawn. All the curves are not shown. Those for Valencia and Falmouth agree so closely, except in July and August, that one line will represent both for most of the year. Similarly, the curves for Armagh, Glasgow, and Stonyhurst agree so exactly in every month that one line suffices to represent them. I have therefore shown on the diagram four curves for all the months, and five for July and August. The curves represent respec- tively (1) Aberdeen, (2) Kew, (3) Armagh, Glasgow, or Stonyhurst, (4) Valencia or Falmouth, and (5) Falmouth alone, in the two months specified. In the diagrams the abscisse represent temperatures and the ordinates the number of days during which those temperatures were ex perjenced. It will be noticed that the line representing Aberdeen lies generally on the left hand of the other lines, showing that the lower tempera- tures are most prevalent at that, the most northern station under consideration. In all but the sammer months the curves for the two south-western observatories show decided peaks, corresponding to temperatures between 40° and 50° in winter and between 50° and 60° in summer, while at all the other stations the maxima are not so marked. The difference between Valencia and Falmouth in August is par- ticularly striking, the figures from 40° to 50° and from 50° to 60° being exactly reversed, Falmouth showing 18°3 days of the higher and Valencia of the lower temperature. The two months July and August exhibit the chief material difference in climate between the south-west of Ireland and the south of Cornwall—a difference to the advantage of the latter. We also see from Table V that at both of these south-western stations the mean daily temperature in July never falls below 50°, and never rises above 70°. This amount of equability of temperature is approached, but not quite reached, at several other stations in the same month. At several of the observatories the range of daily mean temperature in winter exceeds forty degrees. The outcome of the entire enquiry is that, as regards the 15 years under consideration, both (1) the variability of temperature, as defined in the beginning of the paper, and (2) the range of mean temperature, are least at Valencia and Falmouth, the two stations most exposed to the influence of the Atlantic Ocean. Then follows Aberdeen, which, from its close proximity to the sea, enjoys a more equable climate than might have been anticipated from its latitude. The three stations of Glasgow, Stonyhurst, and Armagh form a third group, and they only differ inter se in unimportant particulars. Proc.Roy. Soc. Vol. 47. PU. 9. is ee bation of Mean daily Emperoture | Oe Be Glen GOs sive em man os ; FAL « XXXXKXAX « West, Newman, lith. | a ane —-1890.] The Rupture of Steel by Longitudinal Stress. 363 Kew comes last, as the most continental position, with the greatest variability and the highest amount of range. This latter is due to the greater prevalence of high temperatures there than elsewhere. III. “The Rupture of Steel by Longitudinal Stress.” By CHAs. A. CARUS-WILSON. Communicated by Professor G. H. Darwin, F.R.S. Received March 10, 1890. (Abstract. ) This paper gives an account of experiments made with a view to determining the nature of the resistance that has to be overcome in order to produce rupture in a steel bar by longitudinal stress. The stress required to produce rupture is in every case computed by dividing the load on the specimen at the moment of breaking by the contracted area at the fracture measured after rupture ; this stress is called the “ true tensile strength” of the material. It is well known that any want of unifurmity in the distribution of the stress over the ruptured section causes the bar to break at a lower stress than it would if the stress was uniformly distributed. Hence anything that causes want of uniformity is prejudicial ; for instance, a groove turned in a cylindrical steel bar will produce want of uniformity, and will consequently be prejudicial, the stress at rup- ture being lower according as the angle of the groove is more acute. The most favourable condition of test might appear to be that in which a bar of uniform section throughout its length was allowed to draw out freely before breaking, since in this case the stress must be most unitormly distributed. Experiment, however, shows that the plain bar is not always the strongest. So long as the want of uniformity of stress is consider- able, owing to the groove being cut with a very sharp angle, the plain bar is stronger than the grooved bar; but, if the groove be semi- circular instead of angular, the grooved bar is considerably stronger than the plain, in spite of the fact that the stress is more uniformly distributed in the latter. It would seem, then, that we can strengthen a bar over any given section by adding material above and below it, the change in section being gradual; but such an addition of material cannot strengthen the bar if rupture is caused by a certain intensity of tensile stress over the ruptured section; the added material cannot increase the re- sistance of the ruptured section to direct tensile stress, but it can increase the resistance to the shearing stress. The resistance of a given section of a steel bar does not, then, depend on its section at right angles to the axis, but on its section at 364 Lord Rayleigh. Amount of Oil necessary to [Mar.°27, 45° to the axis, for in that direction the shearing stress is a maximum. From this it would seem that the resistance overcome at rupture is the resistance of the steel to shear. Experiments were made to see whether she: resistance of steel to direct shearing bore to its resistance to direct tension the ratio re- quired by the above theory ; since the greatest shearing stress is equal to one-half the longitudinal stress, we should expect to find the resist- ance to direct shearing equal to one-half of the resistance to direct tension. A series of experiments were made with the result that the ulti- mate resistance to direct shearing was within, on the average, 3 per cent. of the half of that to direct tension. The appearance of the fracture of steel bars is next discussed. It would appear that when the stress is uniformly distributed in the neighbourhood of the ruptured section, the fracture is at 45° to the axis, the bar having sheared along that plane which is a plane of least resistance to shear. The tendency to rupture along a plane of shear may be masked by a non-uniform distribution of stress. Two plates of photographs are added, showing examples of steel bars broken by shearing under longitudinal stress. IV. “ Measurements of the Amount of Oil necessary iv order to check the Motions of Camphor upon Water.” By Lorp RAYLEIGH, Sec. R.S. Received March 10, 1890. The motion upon the surface of water of small camphor scrapings, a phenomenon which had puzzled several generations of inquirers, was satisfactorily explained by Van der Mensbrugghe,* as due to the diminished surface-tension of water impregnated with that body. In order that the rotations may be lively, it is imperative, as was well shown by Mr. Tomlinson, that the utmost cleanliness be observed. It is a good plan to submit the internal surface of the vessel to a preliminary treatment with strong sulphuric acid. A touch of the finger is usually sufficient to arrest the movements by communicating to the surface of the water a film of grease. When the surface-tension is thus lowered, the differences due to varying degrees of dissolved camphor are no longer sufficient to produce the effect. It is evident at once that the quantity of grease required is exces- sively small, so small that under the ordinary conditions of experiment it would seem likely to elude our methods of measurement. In view, however, of the great interest which attaches to the determination of molecular magnitudes, the matter seemed well worthy of investiga- tion; and I have found that by sufficiently increasing the water * * Mémoires Couronnés’ (4to) of the Belgian Academy, vol. 34, 1869. a Ky DA 1890. ] check the Motions of Camphor upon Water. 365 surface the quantities of grease required may be brought easily within the scope of a sensitive balance. In the present experiments the only grease tried is olive oil. It is desirable that the material which is to be spread out into so thin a film should be insoluble, involatile, and not readily oxidised, require- ments which greatly limit the choice. Passing over some preliminary trials, I will now describe the procedure by which the density of the oil film necessary for the ~ purpose was determined. The water was contained in a sponge-bath . of extra size, and was supplied to asmall depth by means of an india- rubber pipe in connexion with the tap. The diameter of the circular surface thus obtained was 84 cm. (33"). A short length of fine platinum wire, conveniently shaped, held the oil. After each opera- tion it was cleaned by heating to redness, and counterpoised in the balance. A small quantity of oil was then communicated, and deter- mined by the difference of readings. Two releasements of the beam were tried in each condition of the slik and the deduced weights of oil appeared usually to be accurate to 1, milligram at least. When all is ready, camphor scrapings are bas osited upon the water at two or three places widely removed from one another, and enter at once into vigorous movement. At this stage the oiled extremity of the wire is brought cautiously down so as to touch the water. The oil film advances rapidly across the surface, pushing before it any dust or camphor fragments which it may encounter. The surface of the liquid is then brought into contact with all those parts of the wire upon which oil may be present, so as to ensure the thorough removal of the latter. In two or three cases it was verified by trial that the residual oil was incompetent to stop camphor motions upon a surface including only a few square inches. The manner in which the results are exhibited will be best explained by giving the details of the calculation for a single case, eg., the secoud of December 17. Here 0:81 milligram of oil was found to be very nearly enough to stop the movements. The volume of oil in cubic centimetres is deduced by dividing 0°00081 by the sp. gr., viz., 0°9. The surface over which this volume of oil is spread is +m x 84? square centimetres ; so that the thickness of the oil film, calculated as if its density were the same as in more normal states of aggregation, is © OGO0ST, ou 163 we 09x47: axel VOC. or 1°63 micro-millimetres. Other results, obtained as will be seen at c onsiderable intervals of time, are collected in the Table. For conve- 366 Motions of Camphor ipon Water. { Mar. 27, nience of comparison they are arranged, not in order . date, but in order of densities of film. The sharpest test of the quantity of oil appeared to occur when the motions were nearly, but not quite, stopped. There may be some little uncertainty as to the precise standard indicated by “ nearly enough,” and it may have varied slightly upon different occasions. But the results are quite distinct, and under the circumstances very accordant. The thickness of oil required to take the life out of the camphor movements lies between one and two millionths of a milli- metre, and may be estimated with some precision at 1°6 micro- millimetre. Preliminary results from a water surface of less area are quite in harmony. For purposes of comparison it will be interesting to note that the A Sample of Oil, somewhat decolorised by exposure. Widens o! Calculated Date. a thickness Effect upon camphor fragments. aes of film. Dec. 17...| 0°40 mg. 0°81 No distinct effect. ie tay Jan. 11 ..} 0°52 1°06 Barely perceptible. Jan. 14...) 0°65 1°32 Not quite enough. Deer 20i rain OAKS t 1°58 Nearly enough. lane deen 7S. 1°58 Just enough. Wee Aiea O- ol 1°63 Just about enough. Dee Steal Oss 1°68 Nearly enough. Jan. 22...) 0°84 1570 About enough. IDES ero na th Wa 1:92 Just enough. Wee i. 5.) Ono 2°00 All movements very nearly stopped. Dece ZO Mane leo! 2°65 Fully enough. A fresh Sample. Jan. 28... 0°63 1°28 Barely perceptible. Jan. 28... 1 06 2°14 Just enough. thickness of the black parts of soap films was found by Messrs. Reinold and Riicker to be 12 micro-millimetres. : An important question presents itself as to how far these water surfaces may be supposed to have been clean to begin with. I believe that all ordinary water surfaces are sensibly contaminated; but the agreement of the results in the Table seems to render it probable that the initial film was not comparable with that purposely contributed. Indeed, the difficulties of the experiments proved to be less than had been expected. Even a twenty-four hours’ exposure to the air of the F 1890.} Stability of a Rotating Spheroid of Perfect Liquid. 367 laboratory* does not usually render a water surface unfit to exhibit the campbor movements. The thickness of the oil films here investigated is of course much below the range of the forces of cohesion; and thus the tension of the oily surface may be expected to differ from that due to a com- plete film, and obtained by addition of the tensions of a water-oil surface and of an oil-air surface. The precise determination of the tension of oily surfaces is not an easy matter. A capillary tube is hardly available, as there would be no security that the degree of contamination within the tube was the same as outside. Better results may be obtained from the rise of liquid between two parallel plates. Two such plates of glass, separated at the corners by thin sheet metal, and pressed together near the centre, dipped into the bath. In one experiment of this kind the height of the water when clean was measured by 62. Whena small quantity of oil, about sufficient to stop the camphor motions, was communicated to the surface of the water, it spread also over the surface included between the plates, and the height was depressed to 48. Further additions of oil, even in considerable quantity, only depressed the level to 38. The effect of a small quantity of oleate of soda is much greater. By this agent the height was depressed to 24, which shows that the tension of a surface of soapy water is much less than the combined tensions of a water-oil and of an oil-air surface. According to Quincke, these latter tensions are respectively 2:1 and 3°8, giving by addition 5°9; that of a water-air surface being 8:3. When soapy water is substituted for clean, the last number certainly falls to less than half its value, and therefore much below 5°9. 4 V. “On the Stability of a Rotating Spheroid of Perfect Liquid.” By G. H. BRYAN. Communicated by Professor G. H. Darwin, F.R.S. Received March 12, 1890. | 1. In my communication on “ The Waves on a Rotating Liquid Spheroid of Finite Ellipticity,”+ I stated that it did not appear possible to give a complete investigation of the criteria of stability of Maclaurin’s spheroid when the liquid forming it is free from all traces of viscosity, and equilibrium is liable to be broken by a disturbance of" a perfectly general character. As the problem in question appeared to be one of considerable interest, I have, since writing the above paper, put the question to the test of numerical calculation in the case of the simpler types of disturbance, and the results thus obtained have been such as to allow of extension to a perfectly general disturbance. * In the country. + ‘Phil. Trans.,’ A, 1889, p. 187. 368 Mr. G. H. Bryan. On the Stability of a [Mar. 27, On page 210 of my paper, I showed that, if we consider only dis- placements determined by the spheroidal sectorial harmonic of the second degree, the limit of eccentricity consistent with stability as obtained from my period-equations agrees with that obtained by Riemann* and Basset.+ This, of course, it should do, for the type of displacement considered in both investigations is the same, viz., one in which the deformed surface becomes an ellipsoid, but does not remain one of revolution. We thus have a necessary condition for stability. But we do not know that it is a sufficient condition. In order that this may be so, it is necessary that the critical form thus obtained shall be stable for all other types of displacement. The object of the present paper is to show that such is, in fact, the case. Were it otherwise, the limit of eccentricity consistent with stability would have to be determined afresh. It is needless to remark that we are here exclusively considering what Poincaré calls ‘ ordinary ” stability, as distinguished from “secular” stability. 2. The symbols employed in the present paper are the same as in my former communication, and the results there proved will be here assumed. For the sake of convenience, the notation and results required for the present work are collected below, and references to the paper in question will be denoted by the letter [1]. The letters «, ¢ are used as defined in [EH], § 4, (11), (12), viz., if e be the eccentricity of the spheroid— , a == sim ‘e, ¢ = cota = (1l—e?*)/e. so that e = (1+¢°)> and ¢ is the reciprocal of the quantity denoted by f in Thomson and Tait’s ‘ Natural Philosophy’ (vol. 2, § 771). The functions pn(f), qn(€), t°(€), un'(C), ave defined as in [H, § 54, equations (24) to (27), viz. :— pal) = segs) C+D" = (-DPPAEW =D) rie MD (3 no) = (+D"(Z) re) = GEE (SZ) +p... @, | a : Cs WG) = pO] (@FDiptopt cine: age ahneana HL Ra fad Cole 8 ers eh ey Patan Re 2s! : : d\s ate elt |, CES LETT. (z) qu(§) Se (4.). * “Gottingen, Abhandlungen,’ vol. 9 (1860), Mathemat., § 9. t+ ‘Treatise on Hydrodynamics,’ vol. 2, p. 124. 1890.] Rotating Spheroid of Perfect Liquid. 369 The quantities g,(¢) and w,'(¢) are expressible in a finite form in exactly the same way as the ordinary spherical harmonics of the second kind.* We have, in fact, gn(€) = (—1)"{ pr(€) cot“ €—R} ....... Thank wa Ths ty s! Ns R’ =| te (¢) cot a 1 i (G); where R, R' are known rational algebraic functions of degree n—1 and x+s—1 respectively in which all the coefficients are positive. For example :— Ps) =& ne) = —{gceot ¢— 1}, un) = (DT 1 Pier — (etl)... «)(O= +754 (2 1} cot” og ae p(t) = 280 +1), qo) = 336? +1) cot ¢— 3, BF ie tee See 2 = 8 +2 #1(¢) = 8¢( +1), w(E) = a RC LY? cotrne = aoe | 8 WO =3E+D, 4X0) = as {3+ 1)cottg— “EEF, and the corresponding functions of the third, fourth, and fifth degrees can be readily written down from my table in the ‘Cambridge Philo- sophical Proceedings’ (loc. cit.), by introducing the necessary changes in the signs, and petine cob! im place of ‘cot =). 3. In [H, § 20] I showed that if we consider only displacements of the surface determined by a spheroidal harmonic of degree n and rank s, the condition of secular stability, which, in the present nota- tion, is PCG) (Ot S) Ue CO) SO remiewee ewer C72), is a sufficient, albeit not a necessary, condition for stability when the liquid forming the spheroid is perfect. That the left-hand member of this inequality is essentially positive when n—s is odd has been proved by Poincaré, and another proof is given below (§ 9). In [E, § 16] I showed that, in the case of the zonal harmonic dis- placements of even degree m, the necessary and sufficient condition for ordinary stability is py (S)- 9 (S) —pa(S) « an) $y {4'(C) uO) —pi() - nO} | a Onteata (ey * “Cambridge Philosophical Society Proceedings,’ 1888, p. 292. + ‘Acta Mathemat,,’ vol, 7, p. 326. Write R; for ¢,°(¢) and 8; for (22 +1)u,s(2). 370 Mr. G. H. Bryan. On the Stability of a [| Mar. 27, and in [E, § 18] that, for a sectorial harmonic displacement, the neces- sary and sufficient condition is that pS) - 4 (E) —tn"(©) Lui(O+- 144 (©) -m(©) —pi(€) -n()} >0 Be) 5 while [H, § 20] if n = 2, the last condition leads to exactly the same results as Riemann’s and Basset’s investigations (as already men- tioned), and gives for the critical form | 1/¢ = 31414567, €= °3183236, approximately whence and the eccentricity = sin 72° 20’ 33” = -9528867. 4. To prove that the spheroid is “ordinarily” stable until this critical form is reached, we only have to show that conditions (7), (8), or (9) (as the case may be) are satisfied by this value of ¢ for every value of » and s. For this purpose I have calculated the numerical values of the products pa(C) . qn(€), and t°(C) .w,°(C) for values of ~ up to 4, and, in the case of the sectorial harmonics (s = n), up to n = 6 inclusive, taking ¢ = ‘3183236. The results calculated to four places of decimals are as follows, the last figure bemg only approximate :— n. . t,5(2) -Un8(S)- | Par (2) a(S) — En8(S) « 1n9(S). af 0 p(2) -q (2) = 11904 a= ail 1 (sectorial) 5360 —, 3456 2 0) "21538 — °0249 2 2 (sectorial) | 3632 — 1728 3 1 1566 ee 3 3 (sectorial) "2803 — ‘0900 a Be TG 1116 + 0788 4 2 1266 + 0638 4 4, (sectorial) . 2303 — ‘0400 5 5 (sectorial) ! "1967 — ‘0063 | 6 ae eae 1743 + ‘0161 From this Table it appears that the expression P(E) - GE) — tn? (C) « Un? (C) is positive, except when n = 2, s = 0, and in the case of the first five 1890] Rotating Spheroid of Penfect Liquid. 371 sectorial harmonics (n = s) in the Table. Thus in every case in which the exact conditions of stability have not been investigated, the sufficient condition for secular stability given by the inequality (7) is satisfied. It remains to apply the criteria (8) and (9) to the cases where (7) is not satisfied. ). First take the case of n = 2,5s= 0. The fact that p, (©) .q (©) —p2(©) - go(F) is negative in the above Table does not indicate that the spheroid in question is secularly unstable for this particular type of displacement. Its meaning is that the spheroid is more oblate than that form for which the angular velocity is a maximum. As pointed out in Poincaré’s memoir,* the disturbed form is here also a spheroid of revolution, and there is no form of “bifurcation” when 7,(¢) . 9,(©) —po(€) - 92(©) changes sign. The condition of “ordinary ” stability, from inequality (8) is P(E) -H(8) —Pl) - (OE) +HAO) mE) —pi(S)- nC) } > 0. For the particular value of ¢ considered, the left-hand member of this inequality is = — 0249+ 2 (3456) = — 0249 +2304 = 2055, and is positive ; therefore (8) is satisfied. Hven in the extreme case when the spheroid becomes flattened out indefinitely, so that ¢ approaches the limit zero, we find P(E) - (6) — P(E) - (O) +HHALO) - (GO) -1 (8) (0) $ 22 Mak no and is positive. This accords with Sir William Thomson’s result that Maclaurin’s spheroid is essentially stable, however oblate, if it is sup- posed constrained to remain spheroidal. 6. Next consider the sectorial harmonics. As the displacement corresponding to n = s = 11s a mere shifting of the mass as a whole, and we are dealing with the critical value of ¢ for displacements determined by the harmonic of degree and rank 2, there are only three cases to consider. Now since t1(€) -m(€) —pi (©) - HG) = 8456, == () UAgiks we find PACS) - HCE) — 83S) « ug? (OQ) +34 (O) . mE) —pi ©) - qi(é) } = —‘0900+°1152 = +0252; * * Acta Mathemat.,’ vol. 7, p. 329. VOL. XLVII. Qn 372 Mr. G. H. Bryan. On the Stability of a [Mar. 27, ©) -GO)-tA®© - 420) +H 4lO- HOP) - a} = —:0400+-0864 = +-0464; PLS) «91 ©) —t5°(E) - Us? (E) +3{41©) -u}(C)—p (©) -n(O)} = —‘0063+-0691 = +:0628. The values of these expressions are all positive; therefore condition (9) is satisfied in each case, and the spheroid is “ ordinarily” stable for the corresponding types of displacement. It is therefore stable for all types of displacement considered in the foregoing table, except that for which it is, by hypothesis, “ critical.” 7. On examining the values of #,°(€).u,(€) given in the Table, it appears probable that as we proceed to harmonics of higher degrees this product diminishes in value, and that condition (7) is satisfied universally in all the cases not considered above. That such is actually the case we now proceed to demonstrate. The results are a slight extension of those obtained in § 10 of Poincaré’s paper, the method here employed being very similar. 8. Cousider the expression— tm" (€) « Um"(Eo) —tn'(o) « Un? (So), and let us examine under what circumstances it is essentially positive. From formula (4) we have tn (€o) - Um" (Co) —tn(o) - Un’ (Eo) ae r 3 ae ee Sees $9 2 ar Sr = (wool | GEniep OO? | eapOP ~ So “fh (YC) etd Ur) / Ver ®) This will be essentially positive if the quantity to be integrated is always positive, that is, if for all values of ¢ lying between {) and ce, (5) -ew) > ° tn®() . tens ( fo) tm'(€) tm” (o) or wiliere <> ©, which will be the case if t,5(€)/tn"(€) increases with €. 9. The result proved by Poincaré, and assumed in the preceding investigations, uamely, that if n—s be odd— ” _ Rotating Spheroid of Perfect Liquid. — 373 PACE) 18) — tHE) « en*() is essentially positive, follows at once. For, as just proved, this will be the case if 7,°(€)/p,(€), that is, t.°(¢€)/¢, mereases with ¢. Now, from formula (2) it is evident that, n—s being odd, t,5(¢) is divisible by ¢, and the quotient will be (¢?+1)* x a rational algebraic function of ¢? in which all the terms are positive. This quotient evidently increases with ¢, which proves the result. 10. Let us now revert to the original question, but suppose in addition that both m—r and n—s are even. We have just shown that tm” (fo) > Un (So) > tn'(€o) : Un'(So)s provided that ¢,°(¢)/tn”(¢) increases with ¢. This will be the case if a tn®(€) AE tm(€) tn’ ee > 0; —t,8(€) ro > OF a tm’ (€) or multiplying by ¢?+1, aa ce (41 ee ~(@+VpE,(6) sig) Since m—r and n—s are both even, it readily anbon that dins(¢) /dé and dt»"(€)/d¢ vanish when ¢ = 0. Hence the left-hand side of the last inequality will be positive when ¢ >0 if it increases with ¢; this condition gives ou again differen- hateng— dt; d ding Um” CS) mal (+1) —) t, a —t,(C) rakone) oe > OF Now tn’(€) and t,5(€) satisfy the differential equations ae dnt ae se C+D St = fn 1)— any bar, a{ ean a eh ume ta (Os etre we get { n(n+1)—m(m+1) a7 since te(©) and ¢ n'(€) are essentially positive, in (Sea OG) =O, or Dota atk Nien, EL Bryan. On the Stability of a [Mar. 27, 2 (n—m) (wh m+ Y= ER > 0 eee, (11... Writing ¢ for €, we see that inequality (11) is a sufficient condition that the expression— bm’ (€) « Un" (©) — tr (E) - Un? (©) may be positive in the case of m—r and n—s both even, provided that (11) is satisfied for all values of ¢ between O and oo. 11. We have to consider two cases :— I. Suppose n =m. Then condition (11) will be satisfied, for all values of ¢, provided that r >s. Therefore ¢,"(€) .Un"(¢) is always > t,°(C€) . Un’(C) whatever be the value of ¢, provided thatr >s. In other words, for given values of n, ¢, the product t,5(€) .%,5(€) in-’ creases as s increases, and is greatest when s = ” (corresponding to. the sectorial harmonics). II. Suppose n—s = m—r and, therefore, n—m =s—r. Condition (11) may be written— s+r m—m) << ntm+1— i > 0 (om) | mm +1 a The first factor is positive provided that n >m. The second is necessarily positive, for 7, s are not greater respectively than m, 1; therefore n+m+1 >s+7, and therefore, a fortior, s+r oral for all values of ¢. Hence, putting s = n—2k, and therefore r = m— 2k, we haye— n+m+1 > bn 2*( ©) : Dp MS) ee ad okt) : tin” EE), provided that m is 0 : where € = "31828. <5 and P(E) 1S) —t5(E) us) > 0 1890.] Rotating Spheroid of Perfect Liquid. 375 and the spheroid is stable for harmonic displacements of the degree 5. From the results of Case II we also have, if n be greater than 6, ta®(€) .un"(S) << t46(C) . m6) and from the Table t(C) .meP(E) < (0) - 91(8) 5 therefore, a fortiort, tn(€) .un"(S) < pil) -a(e), if a > 6. Moreover, by Case I, n'(€) - Un(C) < tn(S) « un(C) 5 therefore, a fortiori, n(E) -mni(O) < pr) 1), or Pi) - nS) —te(E) -uw(C) > 9, where ¢ = ‘3183...., and 7 is equal to or greater than 6. Thus the sufficient condition of secular stability is satisfied for all types of displacement, with the exceptions already considered in which the “ordinary ’’ conditions of stability have been proved to hold good. Hence the results of the present paper prove conclusively that Maclaurin’s spheroid, if formed of perfectly inviscid liquid, will be abso- lutely stable if its eccentricity be less than 0'9528867. If the eccentricity exceed this limit, the spheroidal form will become yee and the liquid will assume the form of an ellipsoid. 13. The state of steady motion which then ensues is intermediate between the forms known as Jacobi’s and Dedekind’s ellipsoids. The “ spin ” of the liquid will be everywhere constant and equal, say, to w,and the form of the liquid free surface will be an ellipsoid, whose principal axes rotate about the least axis with angular velocity iw. That this is initially the case is in accordance with the results of [E, §§ 14, 18], supposing that the roots of the period-equation become complex, for their real part will indicate that the disturb- ance travels round with angular velocity 4w. It is unnecessary to discuss this point at greater length here. It is also to be noted that the results of the present paper quite preclude the possibility, under ordinary circumstances, of Maclaurin’s spheroid ever passing into the form of one or more rings of rotating liquid. This might probably take place if we imagined the liquid surface constrained to remain a figure of revolution. But such hypo- _ thetical circumstances are devoid of interest, and, since it appears from the results of the present analysis that, when we consider displace- eS ee” ag ee aed A ae ee 376 Prof. J. J. Thomson and Mr. G. F. C. Searle. [Mar. 27, ments determined by harmonies of any even degree (7), the “ coefficient of stability’ for the displacement symmetrical about the axis is the last. to change sign, it is clear that hardly any less general constraint would suffice to produce such a result. \ VI. “A Determination of “v,” the Ratio of the Electromagnetic Unit of Electricity to the Electrostatic Unit.” By J. J. THomson, M.A., F.R.S., Cavendish Professor of Experi- mental Physics, Cambridge, and G. F. C. SEARLE, B.A., Peterhouse, Demonstrator in the Cavendish Laboratory, Cambridge. Received March 12, 1890. (Abstract. ) The experiments made by one of us in 1883 having given a value for “uv” considerably smaller than those found in several recent researches on this subject, 11 was thought desirable to repeat the experiments.. The method used in 1883 was to find both the electrostatic and the electromagnetic measures of the capacity of a condenser, the electrostatic measure being calculated from the dimensions of the condenser, and the electromagnetic measure by © determining a resistance which would produce the same effect as that produced by xepeated charging of the condenser when placed in one arm of a Wheatstone’s bridge. In the experiments in 1883 the condenser used in determining the electromagnetic measure was not the same as that for which the electrostatic capacity had been calculated, but one without a guard ring, the equality of the capacity of this _condenser and the guard ring condenser being tested by the method given in Maxwell’s ‘ Hlectricity and Magnetism,’ vol. 1, p. 324. In repeating the experiments we adopted at first the same method as before, using, however, a key of different design for testing the equality of the condensers by Maxwell’s method. We got very consistent results, practically identical with those obtained in 1883. We may mention here, since it has been suggested that the capacity of the leads might explain the low value of “v” obtained previously, that the leads are allowed for by the way the comparison between the two condensers is made, for the same leads are used in the determina- tion of the electromagnetic measure of the capacity of the auxiliary condenser and in the comparison of the capacity of this condenser with the one with the guard ring, and the capacity of the auxiliary condenser is adjusted until its capacity, plus that of the leads, equals the capacity of the guard ring condenser; and in the electromagnetic measurements it is the capacity of the auxiliary condenser, plus that of its leads, which is found. 1890.] Ratio of Electromagnetic Unit to Electrostatic Unit. 377 As the use of the auxiliary condenser introduces additional sources of error, we endeavoured to determine the electromagnetic measure of the capacity of the guard ring directly, using a complicated commutator, which worked both the guard ring and condenser. The first commutator we used was one where the contacts were made by platinum styles attached to a tuning fork ; the results obtained with this were not so regular as we desired, so we replaced the tuning fork commutator by a rotating one driven by a water motor. A stroboscopic arrangement was attached to the commutator, which enabled its speed to be measured and kept constant. With this arrangement, which worked perfectly, we got values for the electro- magnetic measure of the capacity of the condenser distinctly less than those obtained by the old method. We then endeavoured to find out the reason for this difference, and after a good deal of trouble discovered that in the experiments by which the equality of the capacities of the guard ring and auxiliary condensers were tested the guard ring did not produce its full effect. When the guard ring of the standard. condenser was removed and the capacity of the auxiliary condenser made the same, the two methods gave identical results, but the effect produced by adding the guard ring was less in the old method than in the new. We found by calculation that the effect produced by the addition of the guard ring in the old method was distinctly too small, while in the new the observed and calculated effects agreed well together. As the new method was working pertectly satisfactorily, aud as it possesses great advantages over the old one, inasmuch as we get rid entirely of the auxiliary condenser, and, since the commutator 1s a rotating one, its speed can be altered. with much greater ease and accuracy than can be done with a tuning fork, we discarded the old method and adopted the new one. The following are the results obtained by this method :— Electrostatic measure of the capacity, 397-991. Hlectromagnetic Measure. First Set of Experiments. Number of times the condenser is charged per second. Capacity x 107), 64 4.43°427 32 443 °571 48 443°523 © 80 443° 459 64 44.3°298 a9) 44.3°478 42 443°443 Mean, 443°457. a es a ee 378 Ratio of Electromagnetic to Electrostatic Unit. [Mar. 27, Second Sct. 64: 443-043 48 443-097 a2 443°378 80 442-950 64 443°686 55 4.4.3°766 48 443°378 De 443 646 16 443°672 80 443°163 Mean, 443 377. Third Set. 64 4.43°369 a2, 443257 48 433°770 80 443°530 55 4,43°835 64, 443°401 Mean, 443°527. | The mean of all the observations = 443°454 x 107%. The meaus of the observations for different speeds are given in the following table :— Number of times the condenser is charged per second. Capacity x 1071. 80 443°275 64 443-370 dd 4.4.3°693 48 443442 42 4.43443 32 443°463 16 443°672 These agree very well together, the greatest difference being about one part in 1,000. Taking 443°454 x 10! as the electromagnetic, measure of the capacity, the value of ‘fv ” is 299°d8. 1890.] The Superior Cervical Ganglion. 379 VII. “On the progressive Paralysis of the different Classes of Nerve Cells in the Superior Cervical Ganglion.” By J. N. LANGLEY, F.R.S., Fellow and Lecturer of Trinity College, and W. L&E DICKINSON, M.R.C.P., Caius oe Cam- bridge. Received March 15, 1890. It is well known that by stimulating the sympathetic nerve in the neck the following effects can be produced :—(1) Retraction of the nictitating membrane; (2) protrusion of the eyeball and opening of the eye; (3) turning the eye, if previous to stimulation the optic axis is directed nasally, so that the optic axis is directed straight forwards, or it may be forwards and a little outwards; (4) dilation of the pupil ; (5) constriction of the small arteries of the ear, conjunctiva, and of various other parts of the head; (6) in the dog, dilation of the small arteries of the gums, lips, a of some aie parts of the head; (7) secretion of saliva. We have shown that the superior cervical ganglion contains nerve cells, interpolated in the course of the nerve fibres concerned in produc- ing all the above effects, and, further, that these nerve cells are readily paralysed by nicotin.* In this paper we consider the question whether the nerve cells are paralysed simultaneously or in a definite order. That different classes of nerve cells are in some cases un- equally affected by nicotin has been already shown by one of us (L., op. cit.), in so far that in the cat the secretory nerve cells on the course of the cervical sympathetic are more readily paralysed than the secretory nerve cells on the course of the chorda tympani; that in the dog the reverse is the case; and, lastly, that the nerve cells on the course of the secretory fibres of the chorda tympani are paralysed before those on the course of its vaso-dilator fibres. The method employed has been to inject nicotin into a vein, (a) in successive doses, the first dose being rather less than that required to produce complete paralysis of the cervical sympathetic, and to note the order in which the effects normally produced by stimulating the sympathetic disappear; (b) in quantities sufficient to cause com- plete paralysis of the cervical sympathetic, and by stimulating it at short intervals to note the order of recovery of the normal effects of such stimulation. Of course, by injecting the alkaloid into the blood, the peripheral nerve endings, as well as the nerve cells of the superior cervical ganglion, are exposed to its action; but since, as we have shown * Langley and Dickinson, ‘ Roy. Soc. Proc.,’ vol. 46, 1889, p. 423; Langley, ‘Journal of Physiology,’ vol. 11, 1890, p. 146. 1" Be ae aisle -s 380 Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, (op. cit.), even large doses of nicotin* do not prevent the normal sympathetic effect from being obtained on stimulating peripherally of the superior cervical ganglion ; any absence of the normal effect of stimulating the sympathetic in the neck which may be caused by a small dose of nicotin must be due to the action of the alkaloid on the nerve cells of the ganglion. | The method of injecting nicotin into a blood vessel is preferable to that of applying dilute nicotin to the ganglion itself (although this has the advantage of limiting the effect to the ganglion), because of the difficulty of applying the nicotin in such a way as to make certain that equal amounts reach all the nerve cells ; by the latter method it might be possible for the external cells of the ganglion to be paralysed and the internal cells to have escaped paralysis. In the course of our experiments we have naturally had frequent occasion to observe the effect of stimulating the sympathetic upon the blood supply of the lips and gums. It will be convenient to discuss this action before proceeding to the more immediate object of our experiments. Effect of Stimulating the Sympathetic upon the Bucco-labial Region.— The discovery in the sympathetic of the dog of vaso-dilator fibres for the lips, gums, and of some other parts of the head is due to Dastre and Morat.; The whole region in which dilation is produced they call the bucco-facial region; this includes the mucous membrane of the nose, hard palate, of the gums, lips, and the neighbouring cutaneous regions. On the otber hand, the same stimulus produces constriction of the small arteries in the epiglottis, tonsils, and soft palate. Bochefontaine and Vulpiant observed, that sometimes the dilation was preceded by a constriction. Dastre and Morat§ later found a similar constriction; they state that it occurs only with a certain strength of current, which is a little less than that required to produce primary dilation, so that, when electric shocks cause con- striction before the dilation, no effect is produced if the shocks are made a little weaker, and primary dilation is produced if they are made a little stronger. In our experiments, the variation in the strength of the shocks * In a recent experiment upon a rabbit 1450 mgm. of nicotin were injected into a vein without causing the heart to stop. Stimulation of the filament running from the superior cervical ganglion to the internal carotid, z.e., stimulation of the sympa- thetic peripherally of the ganglion, still caused dilation of the pupil. As the experi- ments in this paper show, 5 to 10 mgm. of nicotin are sufficient to prevent stimulation of the sympathetic in the neck, 7.e., of the sympathetic centrally of the ganglion, from producing any effect on the pupil. + Dastre and Morat, ‘Comptes Rendus de l’Acad. des Sciences,’ vol. 91, 1880, pp- 393 and 441. { Bochefontaine and Vulpian, ‘Soe. de Biologie,’ 1880, p. 319. § Dastre and Morat, ‘ Le Systéme Nerveux Vaso-Moteur’ (Paris), 1884, p. 180. 1890. ] The Superior Cervical Ganglion. 381 capable of producing primary contraction was much greater than that given by Dastre and Morat. On gradually increasing the strength of the shocks we find with minimal shocks a slight paling of the lips and gums, which only slowly disappears, so that the original pinkish state of the mucous membrane is not regained for one to two minutes after the end of the stimulation. As the shocks are gradually in- creased in strength the paling becomes more marked, and the after- paling of less duration; with a certain increase in the strength of shocks, the paling continues for a short time after the stimulation, and then gives way to a slight flushing; with further increase, the duration of the after-paling diminishes and the after-flush increases, so that soon the pallor gives way, even during the continuance of the stimulation, to intense flushing. After this, a slight further in- erease in the strength of the shocks causes primary flushing. Marked flashing is first produced in the anterior part of the lips and gums ; a stronger current is required to produce it in the posterior part of the lips and gums and in the hard palate. We have found a primary pallor with very considerable variation in the strength of the current. Thus in one case primary flushing was first obtained with the index of the secondary coil at 9 cm. from the primary coil; with the secondary coil at 18 cm., a slight, though distinct, pallor was produced ; moreover, the after-flush produced by the stronger stimulus was considerably shortened by applying to the nerve the weaker stimulus. In another case the secondary coil was gradually shifted in successive stimulations from 20 cm. to 6 cm. distance from the primary. In all the first effect was pallor; with the weaker stimuli this alone was obtained.* The shocks with the secondary coil at 6 cm. could scarcely be borne on-the tongue; with the secondary coil at about 15 cm. they could not be felt on the tongue. Although some of the results which we have just mentioned do not agree with those of Dastre and Morat, we wisk to point out that they do not conflict with, but rather contirm, the main contention of | these observers, viz., that the sympathetic contains both vaso-con- strictor and vaso-dilator fibres for the bucco-labial region. | _ And from the unequal effects of a moderately strong stimulus on the different parts of the bucco-facial region, we may conclude that the proportion of constrictor and dilator fibres for the different parts * Laffont (‘Soc. de Biologie,’ 1880, p. 341), on stimulating the uncut vago- sympathetic in an atropinised dog, found with all strengths of stimulation primary constriction followed by dilation, the primary constriction being briefer the stronger the stimulation. Apparently, however, the paralysis of the inhibitory fibres of the yagus by the atropin given was assumed, and actual observation on the point omitted ; and Dastre (‘Soc. de Biologie,’ 1880, p. 348) attributes the previous pallor obtained on stimulating the sympathetic to a slowing or cessation of the heart-beat. C0 Ce ae 382 Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, of the region is not the same; and from the unequal effects on different dogs we may probably conclude that the proportion of the two kinds of nerve fibres varies somewhat in different individuals, although it is possible that the results on which this conclusion is based may be caused by a temporary variation in the condition of the animal, for example, in the amount of anesthetic given. It was noticed by Bochefontaine and Vulpian and also by Dastre and Morat that in the cat and rabbit pallor, and not flushing, of the bucco-labial region is caused by stimulating the cervical sympathetic. Like these observers, we have not seen primary flushing with any strength of stimulus; the pallor is marked, except when, for any reason, the gums and lips are already pale; as a rule there is no marked after-flush, but the mucous membrane slowly regains its normal tint. On repeated stimulation of the sympathetic the bucco- labial region remains pale and shows very little alteration. In the course of our experiments upon the dog, we had occasionally seen a slight paling or flushing in the lips and gums on the side opposite to that on which the sympathetic was stimulated; in the cat and rabbit we have paid more attention to this effect, and we find that in these animals, stimulation of the sympathetic produces a bilateral effect. The pallor on the opposite side to that on which the nerve is stimu- lated is greater in the rabbit than in the cat, and is more obvious in the gum of the anterior part of the lower jaw than elsewhere. The degree of the pallor on the opposite side varies considerably in different individuals. Occasionally in the rabbit the pallor is complete on both sides, but in most cases it is much more marked on the side on which the nerve is stimulated. The bilateral action occurs with either sympathetic, although it may be more marked with one sympathetic than with the other; it occurs with all strengths of currents that produce any effect; it is best seen at the beginning of an experiment, for after repeated stimulation of the sympathetic the paling on the opposite side becomes less distinct, and it is much better seen in the anterior than in the posterior part of the lips and gums. In the rabbit a little care must be taken not to stretch the lips too much during the experiment, since this of itself may cause some pallor in the gums. We have also seen some bilateral pallor in the tongue, especially in the tip on stimulation of one sympathetic; but we have paid attention to this in a few experiments only. Hapervment I. Rabbit (C. p. 34). Chloral. Chloroform and ether. See. coil at 9 gives shocks rather weak to tongue. 12.13. Tie and cut left sympathetic (separated from depressor) in middle of neck. Stim. sy., c = 9, for 20 secs.; bilateral pallor in upper and lower lips; in pee a 1890. ] The Superior Cervical Ganglion. 383 the anterior part of the lower lip the pallor is nearly equal on the two sides, in the upper lip the paling on the opposite side to that stimulated is distinct, though slight. 12.30. Cut right sympathetic and both vagi at the level of the upper part of the larynx. Stim. sy.,¢ = 9, for 20 secs. Bilateral pallor in upper and lower lip as before. We may mention that, notwithstanding the difference in the dog on the one hand, and the cat and rabbit on the other, in the effect of stimulating the sympathetic on the bucco-facial region, a small dose of nicotin causes in each case a primary flushing in the region; in the dog the flushmg is most intense, in the cat and rabbit it is compara- tively slight, and may be very brief. Of this we shall have more to say in a later paper on the general action of nicotin. Having thus given the effects which may be expected. to follow stimulation of the sympathetic in the neck, we may now proceed to consider the order in which they cease on injecting into the blood- vessels small doses of nicotin. Our experiments have been made upon the rabbit, cat, and dog. As a rule, in any one experiment, a few only of the effects:can be accurately observed. Thus, in order to observe with certainty a slight dilation of the pupil, it may be neces- sary to pull back the eyelids, in which case a slight movement of the eyelids, if such were caused by the stimulation, might escape observa- tion. It has appeared to us that the effect of stimulating the sympathetic on the movements of the eyelids, the eye, and especially on the nictitating membrane, diminishes with the amount of the anes- thetic given. At any rate, in the rabbit and cat we have occasionally observed so little effect on the nictitating membrane to be caused by stimulating the sympathetic, that no certain conclusion could be drawn from the absence of such effect after giving nicotin. It is necessary, then, to note carefully to what extent the various effects which may be produced by stimulating the sympathetic are in fact produced, immediately before the introduction of nicotin. In nearly all cases the sympathetic in the neck was ligatured and eut. This was done, in the first place, to avoid reflex action, and, secondly, in the hope that, since section of the sympathetic commonly produces the opposite effects of stimulation, the effects of stimulation might thereby become more marked. It has often been noticed that section of the sympathetic produces a transient slight effect only, or even none; this was the case in most of our experiments, so that at the time of injecting nicotin, the ears and pupils on the two sides were alike, occasionally the ear being flushed but the pupil not contracted, or the pupil being a little contracted but the ear not flushed, on the cut side. We have mentioned above that we have sometimes made observa- 384. Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, tions on the progressive paralysis of the different sympathetic actions by giving a dose insufficient to paralyse them all, and some- times by giving a larger dose and noting the progressive recovery. The former method is more troublesome, but brings out greater differences than the latter. The order of recovery is inversely as the order of primary paralysis. The Rabbit.—As anesthetics we have used chloral, and afterwards chloroform and ether, or, more rarely, chloral and morphia. In the ansesthetised animal the eyes are directed forward, and the pupils are rather large; after nicotin has been injected the eyes are directed forward, ard the pupils are in nearly all cases smaller than previously. With regard to the relative time of paralysis of the secretory fibres in the cervical sympathetic, we have made no observations in the rabbit. The easiest comparison to make is that between one of the changes which occur in the eye and the pallor of the ear. In the following experiment the comparison is made between the dilation of the pupil and the constriction of the central artery of the ear. The difference between the ease and duration of the paralysis of these two actions, though always appreciable, 1s nevertheless sometimes slight. The experiment we quote shows, perhaps, the maximum difference which we have observed. Heperiment IT. Rabbit (C. p. 7). Chloral given. Right sympathetic tied and cut in middle of the neck. Stimulation of the sympathetic with a weakish current (ec = 10) produces dilation of the pupil and constriction of the arteries of the ear. ; 1.59. Inject 5 mgm. nicotin. into left jugular vein. 2.4. Stim. sy. for 20 secs., ce = 10; no dilation of pupil, slight pallor of ear. 2.7. Stim. sy. for 20 secs., ce = 9; no dilation of pupil, fair pallor of ear. 2.10. Stim. sy. for 30 secs., c = 8; no dilation of pupil, slight pallor of ear. 2.20. Stim. sy. for 20 secs., ¢ = 10; no dilation of pupil, great pallor of ear. 2.27. Stim, sy. for 20 secs.,c = 10; great dilation of pupil, and great pallor of ear. 2.35. Inject 5 mgm. nicotin. 2.40. Stim. sy. for 30 secs.,¢ = 10; no dilation of pupil, slight pallor of ear. 3.12. Stim. sy. for 20 secs., e = 10; fair effect on both pupil and ear. | 3.28. Stim. sy. for 10 secs., c = 10; nearly maximal dilation of pupil. . 4.7. Inject 5 mgm. nicotin. 4.8. Stim. sy. for 10 secs.,c = 10; great dilation of pupil and pallor of ear. 4.11. Inject 5 mgm. nicotin. 4.15. Stim. sy. for 10 secs.,¢ = 10; great dilation of pupil and pallor of ear. 4.19. Inject 10 mgm. nicotin. 4.24, Stim. sy. for 30 secs., ce = 10; no dilation of pupil, slight pallor of ear. 4.25. Stim. sy. for 60 secs., c = 10; no dilation of pupil, slight pallor of ear. 4.55. Stim. sy. for 60 secs.,¢ = 10; no dilation of pupil, slight pallor of ear. 5.5, Stimulation of the sympathetic on the opposite side caused no dilation of the pupil, but a slight constriction of the vessels of the ear. 4 1890.] — The Superior Cervical Ganglion. 7 385 When we come to compare the effects more in detail, the difficulty is greater. ‘This is especially the case in comparing the vaso-con- strictor effects on the ear, mouth, and conjunctiva; for the pallor of all three, which often lasts for some time, and not for an equal time, as a secondary result of the nicotin makes it difficult to be certain of the beginning of vaso-constrictor action. The movement of the nictitating membrane is more easily paralysed than the movement of the eyelids, and the latter is a little more easily paralysed than the dilation of the pupil, For the rest, the apparent order of ease of paralysis is vaso-constrictors of conjunctiva, vaso-constrictors of mouth, vaso-constrictors of ear; we say apparent order of paralysis, because we have instances from separate experi- ments, in which there has been, so far as could be judged, a simul- taneous recovery in the dilation of the pupil and the pallor of the conjunctiva; pallor of conjunctiva and pallor of mouth; pallor of mouth and pallor of ear. The following experiments will illustrate the time differences observed :— Haperiment ITI. Rabbit (C. p. 20). Chloral. Both cervical sympathetics ligatured and cut. 1.27. Inject into femoral vein 5 mgm. nicotin. 1.29. Stimulate left sympathetic ; no effect. 1.31. Stimulate right sympathetic ; no effect. 1.39. Stimulate left sympathetic; slight constriction of artery at base of ear, otherwise no effect. 1.40. Stimulate right sympathetic; slight constriction of artery at base of ear, otherwise no effect. 1.41. Stimulate left sympathetic for 60 secs. ; fair constriction in artery of ear for about 45 secs.; no effect seen in lips. 1.46. Stimulate left sympathetic for 40 secs.; good constriction in artery of ear, gradual pallor of lower lip, chiefly on left side, but some on right. Slight after-flush. 1.50. Stimulate left sympathetic; slight dilation of pupil; conjunctiva already pale, shows no obvious change, but flushes a little when the stimulus has ceased. No movement of eyelid or nictitating membrane. 2.0. Stimulate right sympathetic. Marked pallor of conjunctiva, fair dilation of pupil; eye opens; no movement of nictitating membrane. Haperiment IV. Rabbit (C. p. 27). Chloral. Right cervical sympathetic ligatured and cut. With secondary coil at 8 (c = 8) the shocks are distinctly felt on the tongue. 2.52. Inject 5 mgm. nicotin into crural vein. 3.20. Stim. sy.,c = 8; usual effects, except that movement of eyelids very slight and movement of nictitating membrane only just perceptible. 3 42, Inject 1 c.c. 1 p. c. curari. 3.47. Stim. sy., good effects, except on nictitating membrane. 3.51. Inject 5 mgm. nicotin. 3.57. Stim. sy., 20 secs.; good constriction of artery of ear; slight pallor of mouth ; no other effects observed. 386 Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, 3.59. Stim. sy., 30 secs.; good constriction of artery of ear; slight pallor of mouth and of conjunctiva, no effect on eyelid or nictitating membrane. 4.0. Stim. sy., 60 secs.; complete pallor of ear, slight pallor of conjunctiva, no dilation observed in pupil, but it is now a little larger than at 3.57. 4.5. Stim. sy., 10 secs.; fair pallor of conjunctiva, moderate dilation of pupil. 4.7. Stim. sy., 10 secs.; eyelids open slightly (previous to the stimulation the eyelids were pressed together). 4.13. Stim. sy., 30 secs.; pallor in lips and mouth is bilateral, but chiefly on the stimulated side. 4.19. Stim. sy., 30 secs., c = 6; eye opens and pupil dilates well, no movement of nictitating membrane. The Cat.—In the cat, the secretory nerve cells of the superior cervical ganglion are paralysed before any others. After a small dose of nicotin (3 to 5 mgm.), stimulation of the cervical sympathetic causes, for a short time, no secretion of saliva, but still causes, or may cause, all the other effects normally seen as the result of the stimula- tion. The difference in the ease and duration of paralysis is in this case very striking. On the other hand, there is often very little difference in the ease of paralysis of the nerve cells of the superior cervical ganglion, which are connected with other classes of nerve fibres. There are some differences which are constant, but which vary very considerably in degree. In the following experiment, the difference between the time of paralysis of the vaso-motor effects on the ear and the dilator effect on the pupil is the maximum we have found. Hxperiment V. Cat (C. p. 24). Chloroform given, then morphia subcutaneously, and occasionally chloroform and ether. Cannula in the duct of the left sub-maxillary gland. Sym- pathetic in neck tied and cut on left side. Cut left chordo-lingual. The pupil is rather large; stimulation of the sympathetic with a weakish current (ce = 9) causes the nictitating membrane to be drawn back, the eye to open, the pupil to dilate, the artery of the ear to constrict, and a secretion of saliva. 12.53. Inject into crural vein, 5 mgm. nicotin. 'The injection causes, amongst other effects, those described above as resulting from stimulation of the sympathetic. 1.0. Stim. sy.,c = 9. Moderate opening of eye, dilation of pupil,and constric- tion artery of ear; no secretion. 1.5. Stim. sy.,¢ = 9; effects as before. 1.13. Stim. sy.,¢ = 9; secretion also. 1.18. Inject 5 mgm. nicotin. 1.28. Stim. sy.,c =9; no effect. 1.45. Stim. sy.,¢ = 9; slight constriction artery of ear, no effect on pupil or on secretion. 1.50. Stim. sy., ¢ = 9; constriction artery of ear, and slight dilation of pupil. 1.53. Stim. sy.,¢ = 9; as before, and eye opens a little. 2.5. Stim. sy.,c = 9; as before, but still no secretion. The effect of the sympathetic upon the nictitating mem’ 1890.] The Superior Cervical Ganglion. 387 paralysed less readily than the other effects of the sympathetic on the eye; in some experiments we have found a very considerable, in others a very slight, difference. Experiment V is an instance of the latter case. Heperiment VI. Cat (C. p. 80). Chloroform. Right sympathetic ligatured and cut. 3.25. Inject into erural vein 4 mgm. nicotin. 3.38. Stim. sy.,c = 9; all the usual effects produced. 3.44. Inject 4 mgm. nicotin. 3.51. Stim. sy.: all the usual effects produced. 3.55. Inject 4 mgm. nicotin. 3.59. Stim. sy., 10 secs., ce = 9; nictitating membrane withdrawn a little, no other effect. 4.03. Stim. sy., 10 secs., ¢e = 8; nictitating membrane slowly drawn back, no other effect. 4.14. Stim. sy., 5 secs.,c = 8; same effect, and pupil slightly dilated. 4.2. Stim. sy., 5 secs., c = 8; as before, and slight contraction of lower eyelid and mouth observed. 4.4. Stim. sy., 60 secs., c = 8; little, if any, immediate effect on tongue, but a slight after-flush. 4.6. Stim. sy., 60 secs., c= 8; mouth chiefly observed, a little paling of tongue and lips at first, changing to slight flushing at end of stimulation; pupil, as before, shows slight dilation only. In this experiment, the dilation of the pupil was noticed before the opening of the eye, but, in some other cases, we have not been able to satisfy ourselves that this occurred. And it is possible that the position of the eyelids, whether nearly closed, or half-open, as they usually are after nicotin, influences the result. Similarly, we have not been able to assure ourselves at what time, in relation to the dila- tion of the pupil, a paling of the conjunctiva, and a paling of the mucous membrane of the mouth, occurs. We are inclined to place them in order of ease of paralysis, as follows: paling of mouth, paling of conjunctiva, opening of eyelids, dilation of pupil. We have not made a comparison between the ease of paralysis of the sym- pathetic effect upon the withdrawal of the nictitating membrane and the constriction of the vessels of the ear. The Dog.—When nicotin, even in large amount, is injected into a vein in the dog, there is a rapid recovery of the effect of stimulating the cervical sympathetic* as regards the coustriction of the small arteries of the salivary glands, the dilation of the pupil, and the secretion of saliva. We have generally observed a slight difference in the time of recovery of these three effects, in the order in which they are mentioned above, but there are special difficulties in the way of determining the exact time when stimulation of the nerve begins » J * Cf. Langley, ‘Journ. of Physiol.,’ vol. 11, 1889, p. 123. VOL. XLVIL. 2F 388 Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, to be effective on the constriction of the vessels of the ear and on the secretion of saliva. The other effects of stimulating the cervical sympathetic are, how- ever, more easily suppressed by nicotin. The one most readily abolished is the flushing of the lips. With regard to the relative ease of paralysis of the movements of the eye, eyelids, nictitatine membrane, and pallor of the mucous membrane of the mouth, we have made a few experiments only, so that we cannot speak of them with much confidence. The order, so far as our experiments go (cf. Exp. VI), is movement of the eyelids, movement of the nictitating membrane, pallor of the lips. Heapervment VIT. Dog (C. p. 11). Morphia. Chloroform and ether. Left sympathetic separated from vagus for about an inch below superior cervical ganglion, ligatured, and cut. With secondary coil at 10 (c = 10), the shocks are distinctly felt on the tongue, but are not strong; with secondary coil at 6 (ce = 6), the shocks are strong to the tongue. Stimulation of sympathetic with ¢ = 10 causes flushing of lips and gums. 1.26. Inject into femoral vein 50 mgm. nicotin. 1.29. Stim. sy., e = 10, 20 secs. ; no effect on eye or lips. 1.34. Stim. sy., ¢ = 6, 30 secs.; no effect on eye or lips. 1.36. Stim. sy., ¢ = 8, 60 secs.; lips slowly become pale on both sides, but this may be the after-effect of nicotin; no other change. The eye quickly shuts on touching the skin near it. 1.43. Stim. sy., c = 8, 60 secs.; pupil dilates—it was large before stimulation. 1.52. Stim. sy., c = 8, 60 secs.; pupil dilates readily, no other change observed ; on left side lips are very pale, and the nictitating membrane is partially drawn back; on right side lips are pinkish, and nictitating membrane is 3 to } way over the eye. 2.10. Stim. sy., c = 8, 60 secs.; edges of lips become paler. 2.16. Stim. sy., c = 8, 60 secs.; momentary movement of nictitating membrane. 2.35. Stim. sy., c = 12, 30 secs. ; eye opens. 2.37. Stim. sy., ec = 7, 30 secs. ; lips slightly flush for 10 to 15 sees., then become pale. “ An interesting result is often obtained by stimulating the sym- pathetic after a rather larger dose of nicotin; in this case, the pupil is rather large, the eye is turned forwards, and the eye is open, but not widely; stimulation of the sympathetic then causes the eyelids slowly to approach one another, 7.e., the eye, instead of opening, becomes more closed. The movement is chiefly in the lower eyelid. On ceasing the stimulation the eye gradually opens to its previous extent. The closing of the eye on stimulating the sympathetic occurs at a time when the stimulation still produces dilation of the pupil and secretion of saliva. It will be remembered that Rogowicz* observed occasionally a similar closing of the eye in the dog when the sym- * ¢ Archiv f. d. ges. Physiol.’ (Pfliiger), vol. 36, 1885, p. 7. 1890. ] The Superior Cervical Ganglion. 389 pathetic was stimulated several days after section of the facial nerve. He attributed it to a contraction of the orbicularis palpebrarum. It is possible that the sympathetic has nerve fibres stimulation of which causes closure of the eye, as well as fibres stimulation of which causes opening of the eye, and that the nerve cells in the superior cervical ganglion connected with the former are less easily paralysed by nicotin; but there is no decisive evidence of this, and the closure obtained may be explained in other ways. Summary. Generally speaking, stimulation of the cervical sympathetic in the dog with minimal effective shocks causes pallor in the lips and gums; with weak to moderately strong shocks, primary pallor followed by flushing; with strong shocks, as shown by Dastre and Morat, primary flushing, but the extent and duration of the primary effect: and of the secondary effect, if there is any, varies in different dogs. In the rabbit and cat, stimulation of the cervical sympathetic always causes, as shown by Bochefontaine and Vulpian, primary pallor in the lips and gums, and the after-flush is not great. The pallor we find is bilateral; the degree of the pallor on the opposite side to that stimulated varies in individual cases, and can be seen on the tongue, as well as on the lips and gums. On injecting nicotin into a vein, certain of the normally occurring’ effects of stimulating the cervical sympathetic cease before the others, 2.e., since all the effects can still be produced by stimulating the fibres running from the superior cervical ganglion, the nerve cells in the ganglion, which are connected with different classes of nerve fibres, are paralysed with different degrees of ease by nicotin. Arranging the various effects im the order of ease of paralysis, we have :— Rabbit. (1.) Withdrawal of the nictitating membrane. (2.) Opening of eye. {@.) Dilation of pupil. (4.) Constriction of blood-vessels of conjunctiva. 105.) Constriction of blood-vessels of lips and gums. 1(6.) Constriction of blood-vessels of ear. In one or two cases, no difference in the ease of paralysis between the bracketed actions has been observed. | Cat. (1.) Secretion from sub-maxillary gland. (2.) Opening of eye. (1) (3.) Dilation of pupil. (4.) Constriction of blood-vessels of conjunctiva. (5.) Constriction of blood-vessels of mouth. 2r2 390 Presents. [ Mar. 27, (2) je Constriction of blood-vessels of ear. (7.) Withdrawal of nictitating membrane. (1) Constant differences between these have not been observed. _ (2) These have not been directly compared, but in separate experi- ments each has been obtained when (1.) to (5.) were no longer seen. Dog. ‘ (1.) Dilation of arteries of bucco-facial region. (2.) Movements of eye and opening of eyelids. (3.) Withdrawal of nictitating membrane. (4.) Constriction of arteries of gums and lips. (1) (5.) Dilation of pupil. (6.) Secretion from sub-maxillary gland. (7.) Constriction of blood-vessels of the sub-maxillary gland. (1) Differences between these have not always been observed. At a certain stage of nicotin poisoning, when stimulation of the sympathetic does not cause withdrawal of the nictitating membrane, but does cause dilation of. the pupil, a partial closing of the eye is obtained by stimulating the sympathetic. It will be noticed that in each animal nicotin abolishes most of the effects of stimulating the cervical sympathetic at very nearly the same time. With regard to these, we think that there is only a wrima facie case for regarding the differences observed as due to an unequal paralysis of the nerve cells of the superior cervical ganglion, for it is possible that the differences may be due to an unequal tonic stimulation reaching the parts by nerve fibres other than the sym- pathetic. But the greater differences observed, for instance, between the secretion of saliva and the dilation of the pupil in the cat, the flushing of the lips and the constriction of the vessels of the sub- maxillary gland in the dog, we do not think can be due to such a cause, and we attribute them to an unequal paralysing action of nicotin upon the nerve cells of the superior cervical ganglion. : The Society then adjourned over the Haster Recess to Thursday, April 17th. Presents, March 27, 1890. Transactions. Berlin :—Gesellschaft fiir Erdkunde. Verhandlungen. Bd. XVII. No. 2. 8vo. Berlin 1890. The Society. Bordeaux :—Societé de Médecine et de Chirurgie. Mémoires et Bulletins. 1888. Fasc. 1-4. 8vo. Bordeaux 1888-89. The Society. ») ae 1890.] Presents. ad1 Transactions (continued). Cambridge, Mass. :—Harvard University. Bulletin. Vol. VI. No. 1. 8vo. [Cambridge] 1890. The University. Cordoba:—Academia Nacional de Ciencias. Boletin. Tomo X. Entrega 3. 8vo. Buenos Aires 1889. The Academy. Cracow :—Académie des Sciences. Bulletin International. Comptes Rendus des Séances. 1890. No. 2. 8vo. Cracovie. The Academy. Leipsic :—Astronomische Gesellschaft. Vierteljahrsschrift. Jahrg. XXV. Heft 1. 8vo. Leipzig 1890. The Society. Firstlich Jablonowski’sche Gesellschaft. Preisschriften. No. 27. Svo. Leipzig 1889. The Society. Liverpool:—Free Public Library, Museum, and Walker Art Gallery. Annual Report. 1889. 8vo. Lwwerpool 1890. The Trustees. London :—Laboratory Club. Transactions. Vol. III. No.4. 8vo. 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Venice:—Reale Istituto Veneto di Scienze, Lettere ed Arti. Atti. per. 6 Yomo VI. Disp. 10. Tomo VII. ° Disp. 1-2. 8vo. Venezia 1887-89. The Institute. Vienna:—Kaiserliche Akademie der Wissenschaften. Denkschriften (Math.-Naturw. Classe). Bd. LV. 4to. Wien 1889; Sitzungs- berichte (Math.-Naturw. Classe). Abth. J. Bd. XCVII. Hem 6-/. bd. .KCVIIL. Bett 1-3; Abth, 2a. Bd. XOVIL. Heft 8-10. Bd. XCVIII. Heft 1-3; Abth. 2b. Bd. XCVII. ier 3-1) Bd. XCVIL. Hert, 1-3 Abvh, 3.° Bd. XOV LL. 7 =. =a 392 Presents. Transactions (continued). Heft 1-4. 8vo. Wien 1888-89; Sitzungsberichte {Philos.- Histor. Classe). Bd. CXVII-CXVIII. 8vo. Wien 1889; Register zu den Banden 91 bis 96 der Sitzungsberichte (Math.- Naturw. Classe). 8vo. Wien 1888; Almanach. 1889. 8vo. Wien. The Academy. Journals. Archives Néerlandaises des Sciences Exactes et Naturelles. Tome XXIV. Livr.1. 8vo. Harlem 1890. Société Hollandaise des Sciences, Harlem. Asclepiad (The) Vol. VII. No. 25. 8vo0. London 1890. Dr. Richardson, F.R.S. Ateneo Veneto. Revista Mensile di Scienze, Lettere ed Arti. 1886, Novembre—Dicembre; 1887, Gennaio-Febbraio; 1888, Gennaio-— Ottobre. 8vo. Venezia. Reale Istituto Veneto. Bullettino di Bibliografia e di Storia delle Scienze Matematiche e Fisiche. Tomo XX. Indici 1868-1887. 4to. Roma 1890. The Prince Boncompagni. Canadian Record of Science. Vol. IV. No. 1. 8vo. Montreal 1890. Natural History Society, Montreal. Fortschritte der Physik i im Jahre 1883. 3 vols. 8vo. Berlin 1889-90. Physikalische Gesellschaft, Berlin. Galilée (Le) 1890. No. 2. 8vo. Paris 1890. The Editor. Horological Journal. Vol. XXXII. No. 379. 8vo. London 1890. British Horological Institute. Naturalist (The) No. 176. 8vo. London 1890. The Editors. Nature Notes. Nos. 1-2. 8vo. London 1890. The Editors. Nyt Magazin for Naturvidenskaberne. Bd. XXXI. Heft 2-3. 8vo. Christiania 1887, 1889. The Editors. Revista do Observatorio. 1890. No.1. 8vo. Rxo de Janeiro. Observatory of Rio de Janeiro. Revue Médico-Pharmacenutique. 1890. Nos. 1-2. 4to. Constantinople. - The Editors. Stazioni (Le) Sperimentali Agrarie Italiane. Vol. XVIII. Fase. 1. Svo. Asti 1890. The Editor. Timehri. Vol. III. Part 2. 8vo. Demerara 1889. Royal Agricultural and Commercial Society of British Guiana. Host and Parasite in certain Diseases of Plants. 393 CROONIAN LECTURE.—‘“On some Relations between Host and Parasite in certainEpidemic Diseases of Plants.” By H. MARSHALL WARD, F.R.S., Professor of Botany, Royal Indian Engineering College, Cooper’s Hill. Received and read February 27, 1890. Introduction—Relations between Physiology and Pathology. I thought I could not better respond to the honour of the invita- tion to give the Croonian Lecture this year than by choosing a subject from the domain of plant pathology, which should, at least, have the merit of being of general interest and importance, and it seemed probable that an account of some of the more conspicuous features and recent results of the study of certain fungoid dis- eases might be so placed before you that it should illustrate not only the kind of progress which plant pathology is making, but also show how dependent that progress is, and must be, on the advances of physiology. Moreover, I hope to be able to demonstrate that the connexion between these two modern branches of science is (in botany, at any rate, and I have no reason to doubt that the truth applies to the animal kingdom as well) so close and so mutual that the problems which arise daily appeal to students of both depart- ments, and necessitate that each shall know what the other is about. This, of course, is not the same as saying that either branch of study is deficient in its special questions; but it cannot be too much insisted upon that, while the facts and generalisations of pathclogy often throw light on physiological questions, the enquirer into the pathology of plants has to pause at almost every step and ask some question in physiology, and his progress may be slower or more rapid in proportion as the answer is obscure or the reverse. For, after all, the pathology of plants embraces those phenomena of abnormal life-processes which can go gn in the long series of changes between normal, healthy, vigorous life, and the cessation of that life as such, 7.e., death; and it is obviously impossible to study these abnormal life-processes (pathological) without reference to the normal ones (physiological). In other words, then, pathology is the study of disturbed or abnormal physiological processes, and I thought that it would be possible to interest you in some of the phenomena cf abnormal plant life, and especially in the working of some of these factors which result in producing certain diseases,in which fungi play the prominent part, and which occasionally assume the nature of epidemics so suddenly that the phenomena continually prove too much for the inherent credulity of those who are not in the habit of VOL. XLVII. 26 304. Prof. H. Marshall Ward. “Phe Relanonsise ae investigating complex chains of causation, and give rise to specula- tions of the most superstitious description. The Diseases of Plants and their Classification, &c. The diseases of plants have been classified in various ways, at different times, and by different observers. Passing over the earlier attempts,* based for the most part on errors which were natural at fA ve Fie. 1. A young coffee plant (reduced), the leaves of which are badly infected with the Uredinous fungus Hemileia vastatrix. The paler spots are bright orange-yellow, the centre gradually turns brown, and then black as the tissues are destroyed ; the granular appearance on the younger spots is due to the spores of the fungus. Such yellowing of the leaves is a common symptom of such diseases, * An excellent account of the earlier writers appeared in the ‘ Gardener’s Chronicle,’ 1854, from the pen of the late Rey. M. J. Berkeley, F.R.S. Host and Parasite in certain Diseases of Plants. 395 the time, but some of which seem almost incomprehensible now, as some of our present errors will appear in the future, it may be said that no very exhaustive survey of these diseases as a whole was possible until comparatively recent times. The successive attempts of modern authors* have been almost entirely along one or other of two lines: they have classified the diseases either (1) according to the symptoms externally visible and the organs attacked, or (2) according to the causes which seem most concerned in produping the disease. Whichever method is adopted, it is repeatedly found that large assumptions have to be made and recognised in order to bring given diseases into the sphere of treatment for the time being, and diffi- culties of very peculiar nature continually make themselves felt. As an instance, we may take the well-known symptom of the appearance of yellow leaves. Not only are yellow leaves charac- teristic of many diseases due to fungi of the groups Uredinez and Ascomycetes (Peziza, Hysterium, Polystigma, §c.), or to the attacks of insects (e.g., Aphides), but they may indicate ‘‘something wrong ’”’ at the roots—want of drainage, over-drainage, or lack of some ingredient such as iron, or the presence of some noxious mineral, to say nothing of parasites (Phylloxera, Melolontha, Agaricus melleus, §c.). In cold weather in the spring yellow leaves may mean that the temperature is too low for the production of the green chlorophyll ; while frost is responsible for the yellowing of other leaves by a totally different procedure—the acid substances in the cells are enabled to diffuse through to the chlorophyll corpuscles and kill them. Yellow leaves often indicate the access of too little sunlight, but they may be produced by too intense insolation and consequent destructive changes in the cells. Leaves injured by acid gases and poisonous substances in smoke also turn yellow, and the yellow hue of autumnal leaves is well known, while we have numerous yellow varieties of leaves among cultivated plants, the causes for which are less clear. These are by no means all the cases observable, but they will suffice to show how little can be inferred from a symptom which may be due to so many causes, operating alone or in combination, be it said. In fact, as a symptom, the yellowing of leaves is of scarcely any classi- ficatory value, and we are driven to the conclusion that the leaves of plants react to most injuries by turning yellow. It is much the same with other classes of disease named after the prominent symptoms. What is usually termed “canker,” for * The literature is for the most part in Hallier’s ‘Phytopathologie’ (1868), Frank’s ‘Krankheiten der Pflanzen’ (1880), and Sorauer’s ‘ Pflanzenkrankheiten ” (2nd ed., 1886). 262 396 Prof. H. Marshall Ward. The Relations between Fie. 2. Oaks in the neighbourhood of a manufacturing town, the leaves of which were damaged by acid gases. The injury results in the production of yellow spots on the leaves, and the latter eventually turn wholly yellow and brown, and die. From a photograph taken August 8th, 1882. instance, is in different cases referred by different authorities to the agency of excessively low temperature (frost*), or of insects,f or of fungi,t or of two of these combined, to say nothing of other causes. If we now ask how the matter stands with regard to the method of clas- sifying diseases of plants according to their chief causes, the answers. are no clearer. It is the custom to proceed somewhat as follows :— There are, first, diseases due to the action of the non-living en- environment (soil, climate, mechanical injuries, &c.); and, secondly, diseases due to the attacks of living beings (parasitic insects, fungi, &e.). Now, leaving out of account altogether certain totally unexplained diseases, such as some forms of “gumming,” &.,1t becomes apparent that we are liable to all kinds of errors unless we recognise that no one factor ever accounts for a disease; it is not so obvious, however, that the changes which result in disease are usually due to several factors acting in concert or successively, and I shall try to show that, even in marked cases, it is by no means always easy to decide which * Sorauer ‘ Pflanzenkrankheiten ’ vol. 1, 1886, pp. 305—448. t+ Frank, ‘ Krankheiten d. Pflanzen,’ 1880, p. 719. { Hartig, ‘ Lehrb. d. Baumkrankheiten,’ pp. 89 and 109. —T ane Host and Parasite in certain Diseases of Plants. 397 A ‘linge Fig. 3. The same oaks as those of fig. 2, photographed from the same spot on July 20th, 1888. The cumulative injury ,to the leaves in successive years results in the death of the trees. of the co-operating factors are to be brought into the foreground, though, until this is decided, it may be a hopeless task to consider prophylactic measures. As examples of the complex interactions that may be met with in the first group of diseases as arranged above, we might consider the following :— A soil is said to be unsuitable as regards aspect, or elevation, or steepness, but it will be evident that the degree of unsuitableness may vary with the depth and structure of the soil, and with the lati- tude, the proximity of mountain ranges or the sea, and other factors which influence the climate; instances of disease, in the broad sense of the word, are frequent enough where two neighbouring crops or growths of the same species of plant suffer in very different degrees, owing to slightly different combinations of such factors of the environment; and the difficulty of referring the disease more espe- cially to any one cause only increases with experience. Or, take the structure, &c., of the soil. It may vary in chemical composition, in capacity for retaining water, in physical texture, and so forth; and the enormous differences to be met with are best known to those who have to cultivate large estates or continuously observe large tracts of country. But it is matter of general experience that the chemical composition of a soil is one of its least important features la neti ihe 398 | Prof. H. Marshall Ward. The Relations between within wide limits; much more important is the amount of water and air in it, and the way they are held there. These, especially under certain crops, affect the climate of the immediate locality, and all kinds of complexities result. Tio mention one only, there are certain combinations of soil and climate, &c., which result in the trees being ‘‘frost-bitten”’ whenever there are late spring frosts. In some cases it is found that mere drainage puts an end to the evil ; this means not only a removal of water, but an increase of air in the soil and general elevation of temperature. In others it is noticed that the more shaded trees suffer most; this is in part because their tissues are more watery, and their cell-walls more delicate. In others the injury occurs on a particular side of the tree, and is ruled chiefly by the prevailing winds. Now, here is a problem of con- siderable complexity. Frost (1.e., too low a temperature) is the agent directly concerned, but it accomplishes the injury because the shoots are too succulent, and the tissues too feebly developed, to resist a temperature which they would be perfectly able to resist if more carbohydrates had been formed under a brighter light, and if less water containing more oxygen had ascended their stems, and so forth. It is at least difficult to class such cases, and they arise every day. Who would have suspected that one result of bringing the larch down from its mountain home would be to render it more lable to injury from certain pests kept m abeyance on its native Alps, because it is stimulated to put forth its young leaves when the insects are about, which puncture the cortex and afford means of entrance .for certain parasitic fungi ? On turning attention to the diseases referred to the action of living organisms, we meet with difficulties rather greater than less, and it is. chiefly on account of these that so many wild hypotheses are current: as to this class of diseases. Omitting more than a mere reference to the diseased or weakened conditions due to competition with weeds, and with overbearing associates, such as Thelephora lacumata, which may overshadow young Conifers, and eventually kill them simply by depriving them of light,* and to the various parasitic Phanerogams such as Loranthus, the mistleto, dodder, &c.,f we come to an enormous series of diseases due to parasitic insects (and other animals) and fungi. The chief difficulty connected with the investigation of diseases. induced by fungi is due to the double set of complications involved. It is difficult enough to unravel the tangled skeins ef causes and effects. * R. Hartig in ‘Untersuchungen aus d. Forstbot. Institut zu Miinchen,’ 1880, p. 164. . + See Solms-Laubach, ‘‘ Ueber den Bau und die Entwicklung der Ernihrungs- organe paras. Phaner.” (‘ Pringsheim’s Jahrbiicher,’ vol. 6, 1867-8, p. 509). Host and Parasite in certain Diseases of Plants. 399 in the case of the comparatively simple diseases referred to above ; but when the problem consists in disclosing the life-history of a micro- scopic fungus on the one hand, and then in discovering its relations to the plant (the biology of which is always assumed to be known) on or in which it passes the whole or part of this life-history, on the other, the matter rapidly attains unexpected proportions. Yet this is never the whole, or necessarily the major part, of the real problem— the nature of the disease—and before that can be even approximately solved we have to obtain an ingight into the influence of the non- living environment on both the host-plant and the parasitic fungus, an inquiry which may assume appalling proportions before it is far advanced. Nor is this the end, though it is quite sufficient to account for the fact that we never know all about any of these diseases. There is a factor—or set of factors—which always tends to baffle the inquirer into these matters, and that is the internal disposition* of the parts of the organisms concerned ; call it what we will—constitu- tion, inherited disposition, &c.—the fact remains that the host-plant _and the parasite alike exhibit peculiarities of behaviour that cannot be explained in the present condition of science as directly due to the action of any external agency of the environment, although we are no doubt right in concluding that it is the outcome of the cumu- lative results of the vicissitudes of the species and its ancestors in the long past. But it is just the reactions of this constitution, and its variations induced by changes in the physical environment, which are so often and so persistently overlooked, although the attempt to understand any disease is hopeless, unless we take them into consideration. I hope to show, in the course of this lecture, how the modern study of the pathology of plants differs in methods from that of our prede- cessors, especially in this very particular—the recognition of the reactions of the host to its living and non-living environment, as apposed to the reactions of the parasite to its living and non-living environment, ard, further, of.the truth that disease is the outcome of a want of balance in the struggle for existence just as truly as normal life is the result of a different poising of the factors of existence. Of course, inasmuch as the abnormal state of affairs, while detri- mental to the host, is the best possible for the parasite, we have here the elements of a paradox; but there is no real confusion of ideas here; we are concerned with a particular case, illustrative of the struggle for existence, in which a given set of variable factors of the environment favour one organism at a time when they disfavour another. * Sachs, ‘ Lectures on the Physiology of Plants,’ pp. 189—204. 400 Prof. H. Marshall Ward. The Relations between The Host-plant, and the Behaviour of wts Normal Tissues. I begin by briefly calling attention to the healthy tissues of a normal green flowering plant, and we need only consider for the moment what is going on in the parenchyma cells of a leaf or stem, such as every one knows the anatomy of. In a selected piece of such tissue we find the mass cut up into a number of thin-walled cham- bers, the cells, each of which contains a lining of living, colourless protoplasm, with strands or plates of the same running across; in this protoplasm are embedded the nucleus and the green chlorophyll ¥Fia. 4. Portion of the cell-tissue of a higher plant, in longitudinal section and highly magnified. Each of the cells is bounded by the cellulose cell-wall; and this is lined by the protoplasm in which are embedded the nucleus (a—e) and the green chlorophyll corpuscles (g—i). This protoplasm encloses the cell- sap, and strands of the former may pass across (as at f), or plates of proto- plasm may separate the sap of one part of the cell from that of another (Kny). corpuscles. In the large vacuoles or sap-cavity of each cell is a clear liquid, the cell-sap, consisting of water with small quantities of mineral salts, dissolved gases, organic acids, and salts and other crystalline and non-crystalline substances in various proportions at different times.* Of course, I need not here enter into a long de- * On the subject of the extreme complexity of the cell-sap and protoplasm, see Pfeffer, ‘“‘ Beitrige zur Kenntniss der Oxydationsvorginge in lebenden Zellen” ‘Abhandl. Math.-phys. Classe Sachsischen Gesellsch. d. Wiss.,’ vol. 15, 1889, pp. 455—466). ' Fost and Parasite in certain Diseases of Plants. 401 scription of the histological peculiarities of the cell, and it will probably suffice to remind you that great differences occur in detail as to the size of the cell, the thickness of the wall, number and sizes of the chlorophyll corpuscles, and the preseuce or absence of colouring matters, crystals, various organised bedies, and so forth. Finally, it will be remembered that all the parts—cell wall, nucleus, chlorophyll corpuscles, and protoplasm generally*—are more or less thoroughly saturated with water, and that aqueous vapour and gases will be found in varying proportions in the passages between the cells, and con- tinuous with the atmosphere, on the one hand, and with the water in the roots and soil, on the other. Let us now inquire what these normal living cells are doing when they still form an integral part of the tissues of the healthy plant. In the first place, they are respiring. That is to say, the protoplasm absorbs oxygen gas} brought to it in the water from the roots, from the intercellular spaces which communicate with the atmosphere by means of stomata and lenticels, and from the chlorophyll corpuscles when they are assimilating in bright light. This oxygen enters in solution into the protoplasm, and combines with some of the bodies which for the time being enter into the composition of this complicated structure. The effects of these unions of the oxygen are expressed in molecular disturbances in the protoplasm: some bodies are broken down, others enter into new unions. Finally, the disturbing actions of the energetic oxygen result in the combustion of certain carbon- compounds to carbon dioxide and water, and these escape from the field of action: such combustion implies the liberation of energy, and we recognise this in the complicated movements 4nd life-processes set up in the protoplasm and in the rise of temperature, which can be proved to take place.{ One point of importance should be insisted on from the first. When the oxygen-molecule enters the protoplasm, it must be pictured as coming into a busy arena, where numerous but definite possibilities are presented to it, and although we are not in a position to trace its movements,§ and the intermediate effects of these, in detail, the evidence shows that while the quantities produced accord with the general view that it is such substances as glucose, * For particulars as to these, cf., e.g., Zimmermann, “ Dié Morph. und Physiol. der Pflanzenzelle ;” Schenk’s ‘ Handbuch,’ vol. 8, Heft 2, pp. 497—700; and Noll, “Die wichtigsten Ergebnisse der botanischen Zellenforschung in den letzten 15 Jahren” (‘ Flora,’ 1889, pp. 155—168). t Cf. Sachs, ‘Lectures on the Physiology of Plants,’ pp. 395—408; Vines, “Physiology of Plants,’ pp. 195—202; Pfeffer, ‘ Pflanzenphysiologie,’ vol. 1, pp. 346—363. . ~ Rodewald, ‘Pringsheim, Jahrb. f. wiss. Bot.,’ vol. 17, 1886, p. 338; vol. 19, 1888, p. 221. § It may be regarded as certain that for respiration it does not suffice for a body to be merely in the protoplasm (see Pfeffer, ‘Oxydationsvorginge,’ pp. 489—490). 402 Prof. H. Marshall Ward. The Relations between and similar carbohydrates, which yield the fuel and energy—as they do in ordinary combustion—nevertheless, we must not fall into the error of supposing that so much sugar or starch in the protoplasm is forthwith and simply oxidised to carbon dioxide and water, nor may we conclude that the process is one of simple and direct oxidation at all.* In the first instance, it is chiefly owing to the vagaries of the oxygen-molecules in the living protoplasm, that the latter exercises the processes of metabolism, the second group of functions we have to consider. The metabolic processes which can be referred to the changes brought about during respirationy result in two series of events. On the one hand, compounds of various kinds pass out of the protoplasm —the arena of metabolic activity—into other parts of the cell, and especially into the cell-sap; and, on the other hand, bodies of com- paratively simple constitution are bronght from the cell-sap and elsewhere into the arena of activity, and there worked up into more complex bodies. It is impossible to separate these two sets of pro- cesses; but, if we abstract them mentally, for purposes of simplicity, we may say that the followimg series of events important for our present purposes are taking place. Carbohydrates, especially in the form of glucoses, are being taken up into the protoplasm, and built up into the structure of its sub- stance: here, owing to the attacks of the oxygen of respiration, the structures into which they enter are more or less broken down— as before said, not necessarily merely oxidised as such or directly— and the complex into which they have temporarily entered becomes decomposed, again to be built up anew by the aid of more carbo- hydrates, and so on repeatedly. Among the temporary products of these destructive processes, in the complex alternations of building up and breaking down here going on, we find certain nitrogenous compounds (amides and allied bodies) like asparagin, leucin, glutamin, &e., playing important parts. The evidence goes to show that so long as plenty of carbohydrates are at the disposal of the protoplasm, these amide-hodies are again worked * For the older literature, see Pfeffer, ‘Pflanzenphysiologie,’ vol. 1, p. 353; Sachs, ‘ Lectures on the Physiology of Plants,’ pp. 395—408: and Vines, op. cit., p. 214. Then consult Palladin, in ‘ Berichte d. Deutsch. Botan. Gesellsch.,’ 1886, p. 322 ; 1887, p. 325; ‘ Botan. Centralblatt,’ vol. 33, 1888, p. 102; Pfeffer, “‘ Beitrige zur Kenntniss der Oxydationsvorginge in lebenden Zellen”’ (‘ Abhandlg. Math.-phys. Classe Sachsischen Gesellisch. d. Wiss.,’ vol. 15, No. 5, 1889, pp. 375—518, especially 480—500), where the more important special literature is quoted. + Strictly speaking, metabolism includes all the chemical changes in the proto- plasm which constitute it living substance; it is a mere convention to speak of different kinds of metabolism, and to separate carbon-assimilation as a special func- tion. Fost and Parasite in certain Diseases of Plants. 403. up with them into the more complex bodies, to be again broken down, and repeat the process,* and so on. If, however, for any reason a lack of these carbohydrates occurs,, then these amide-bodies increase for the time being, and the proto- plasm suffers accordingly ; in fact, it undergoes further decompositions. as a result of starvation. The evidence also goes to show that organic acids (such as malic, citric, tartaric, oxalic, &c.) are formed in the protoplasm, and accu- mulate in the cell-sap during these metabolic processes, as products. of incomplete oxidation, and their variations in quantity depend greatly on the activity of these metabolic processes, and, therefore, on the intensity of respiration. A fact of primary importance for us is. that these organic acids increase considerably in amount under con- ditions which lead to less complete oxidation, and, conversely, they decrease when certain oxidation-processes in the cell are promoted. In other words, they are continually being formed and destroyed in metabolic changes, and sometimes one process, sometimes another, predominates. Asa third group of life-processes which our selected cells would exhibit, we may regard the phenomena of growth; processes which are intimately dependent upon respiration and metabolism, and, indeed, inseparable from them in life. For our present purpose, it suffices to regard growth{ as consisting in an extension of the still soft cellulose cell-walls, which tends to. increase the area of the membrane at the expense of their thickness, and in a compensating increment in their thickness due to the activity of the protoplasmic lining in secreting and laying on cellulose on the inside of, or even in the structure of, the wall. Passing over the fact that the secretion of this cellulose is another manifestation of metabolic activity on the part of the protoplasm, it is important to. notice that growth is only possible so long as respiration is proceeding, and so long as the cell is turgid. Now turgidity depends on the * See E. Schulze, ‘ Landwirthschaftliche Jahrbiicher,’ 1876, vol. 5, p. 848;. Borodin, ‘Bot. Zeitg.,’ 1878, col. 801; Palladin, ‘‘ Ueber Eiweisszersetzung in d. Pflanzen,” &c. (‘ Ber. d. Deutsch. Bot. Gesellsch.,’ 1888, p. 205, see p. 212). Further literature in Pfeffer, ‘ Pilanzenphys.,’ p. 301. + See especially Warburg, “ Ueber die Bedeutung der organischen Sauren fiir den Lebens-process der Pflanzen” (‘ Unters. aus d. Bot. Inst. zu Tibingen,’ 1886—88, vol. 2, pp. 53—152, where the literature is collected up to date; and Palladin,,. “ Athmung und Wachsthum”’ (‘ Ber. d. Deutsch. Bot. Gesellsch.,’ 1886, pp. 322— 328), and the same on “ Bildung der organischen Sauren in den wachsenden Pfian- zentheilen”’ (ibid., 1887, pp. 325—326). { For a general account of growth, cf. Sachs, ‘ Lectures,’ pp. 411—424 and 567 —569. § See de Vries, ‘Unters. itiber die mechanischen Ursachen der Zellstreckung,” Leipzig, 1877, and the literature there quoted. AOL Prof. H. Marshall Ward. The Relations between presence in the cell of water under pressure: that is to say, in a turgid cell there is in the sap cavity sufficient water not only to supply all the demands of the cell-walls and protoplasm, but to keep them distended as well, and this to such a degree that the cellulose walls, with their lining of protoplasm, are positively stretched in opposition to the elastic resistance offered by the former. Recent re- Searches have proved that this excess of water is largely due to the osmotic attraction exerted by the organic acids and their salts dis- solved in the sap of the cell,**and since we have seen that the forma- tion and destruction of these acids depend on the processes connected with oxidation and respiration, we obtain a futher glimpse into the complicated correlations here concerned. For our purpose the im- portant points are that, during active turgescence, the growing cells tend to become very watery and their cell-walls to be thinned by stretching, and this in spite of the activity of the protoplasm in adding new materials; while bodies such as soluble amides and organic acids are being formed continuously and in relative and vary- ing abundance, to undergo further changes in the never ending turmoil of metabolism, as already indicated. But it is evident that these processes of respiration, destructive metabolism, and growth must sooner or later come to an end if the stores of carbohydrates fail, since these are the substances which ultimately supply the fuel for respiration, and which form the raw materials by means of which new protoplasm may be constructed ; and it is well known that the plant respires and grows to death if placed in such circumstances that no new supplies of these substances ‘are possible. We must remember that we are concerned with normal green cells, however, and we have now to consider the new set of events due to the assimilative action of the chlorophyll corpuscles to which these cells owe their colour. Itis not necessary to remind you that this process of carbon assimilationt consists in the coming together of carbon dioxide and water in the green corpuscles, where, by means of energy obtained in certain rays of sunlight, the molecules of the carbon dioxide and water are torn asunder and eventually in part rearranged; speaking generally, we may say that some of the constituents (oxygen) escape, while others (carbon, hydrogen, and * De Vries, “Ueber die Bedeutung der Pflanzensiuren fiir den Turgor der Zellen” (‘ Bot. Zeitg.,’ 1879) ; also Palladin, ‘‘ Bildung der organischen Sauren in den wachsenden Pflanzentheilen ” (‘ Ber. d. Deutschen Bot. Gesellsch.,’ 1887, p. 325). ‘Other literature will be noticed where necessary as we proceed. + For a general account of carbon assimilation, see Sachs, ‘ Lectures on the Phy- siology of Plants,’ especially pp. 296—323. t This oxygen is not active (see Pfeffer, ‘ Beitr. z. Kenntn. Oxydationsyorgange,’ p- 478). Host and Parasite in certuin Mseases of Plants. 405 oxygen) form new combinations, which result in the production of carbohydrates, which then separate from the protoplasm.* We are here, of course less concerned with the difficulties which beset the questions, what rays of light are concerned in this process, how their energy is employed in the chlorophyll, and what part the chlorophyll itself takes directly in the process; or with questions as to the exact products formed during the putting together of the carbohydrate in the protoplasm of the chlorophyll corpuscle, and so on, than with certain well-established facts and conclusions, such as the following. The process of building up the products obtained by the decompo- sition of the carbon dioxide and water in the protoplasm into carbo- hydrates goes on continuously in the sunlight, so long as it is sufficiently intense, and the excess beyond what is immediately re- quired for the nourishment and respiration (7.e., the maintenance of metabolic activity) of the living substances of the cell takes the final form (usually+) of starch. Free oxygen escapes all the time, and, in so far as this is not absorbed for purposes of oxidation, there and then in the cell, this oxygen goes to enrich the atmosphere. Moreover, these temporary stores of starch are continuously being transformed into soluble glucoses, by means of diastatic ferments{ in the proto- plasm; this process goes cn day and night, and its result may be easily demonstrated in the case of leaves removed from the plant after exposure to the sunlight during the day. After afew hours in a warm, dark, normal atmosphere, relatively large quantities of glucose are found in the cells, while the starch is disappearing. This glucose, I need hardly remind you, is the soluble movable form of the carbo- hydrates,§ and it is worked up again, so far as it is in excess of the * The literature of this part of the subject is enormous, and dates from Priestley (‘ Phil. Trans.,’ 1772) to the present time. It may be said to fall under four heads: (1) the nature and functions of chlorophyll ; (2) the absorption of carbon dioxide and the evolution of oxygen; (3) the intensity and kind of light necessary ; (4) the chemical processes which intervene between the coming together of the carbon dioxide and water and the production of the final visible product—starch. I shall, naturally, here refer only to such special literature as bears on the main subject of the present lecture. + Sachs, ‘ Flora,’ 1862, Nos. 11 and 21, and 1868, p. 33; also ‘ Bot. Zeitg.,’ 1862, eol. 366; Godlewski, ‘ Flora,’ 1873, p. 378, and ‘ Arb. des Bot. Inst. in Wirzburg,” 1873, vol. 1, p. 343. Again, Sachs, ‘ Arb. des Bot. Inst. Wirzburg,’ vol. 3, Heft 1, 1884; G. Kraus, ‘ Jahrb. fiir wiss. Bot.,’ vol. 7, 1870, p. 511 ; Famintzin, ‘ Jahrb. fiir ge Bot.,’ vol. 6, p. 34. Bere wuctrky, ‘ Die Starkeumbildenden Fermente,’ 1878. § Numerous interesting results have been obtained of late years confirming and strengthening our theory of carbohydrate assimilation : see Bohm (‘ Bot. Zeitg.,’ 1883, col. 33), A. Meyer (‘ Bot. Zeitg.,’ 1886, col. 81), Laurent (‘ Bot. Zeitg.,’ 1886, col. 151), who proved that leaves deprived of starch can form it from various sugars, glycerine, &e.; also Wehmer (‘ Bot. Zeitg.,’ 1887, col. 713), O. Low (‘ Ber. d. Deutsch. Chem. 406 Prof. H. Marshall W ard. The Relations between immediate requirements of the living protoplasm, into the form of reserve starch, &c., by the protoplasm.* At certain periods, therefore, the cells may contain relatively large quantities of this soluble, nutritious, and easily oxidised glucose. We have still to refer shortly to another set of events taking place in the normal living cells, the connexion of which with the above simultaneous functions will be obvious. This is the passage of water from one cell to another, a process depending essentially upon the modified evaporation—transpirationt—going on at those surfaces of the cell walls which are in contact with the air in the intercellular spaces, &c., and the rapidity and magnitude of whose movements depend on a variety of circumstance. . This water comes from the vascular system, by which it is brought up from the soil after being absorbed by the root-hairs, and it contains traces of the necessary mineral salts—chiefly sulphates, nitrates, and phosphates of calcium, magnesium and potassium, in small, and varying quantities—as well as dissolved gases. Whether the oxygen dissolved in the water absorbed at the root reaches the cells higher up in the plant or no, it is at least clear that the water in these cells becomes oxygenated by contact with the atmospheric air which pene- trates into the intercellular spaces, wid the stomata and lenticels.f Moreover, it is impossible to doubt that oxygen reaches the water in the cells from the assimilating chlorophyll corpuscles. However, we are not confined to inferences in this connexion, since Pfeffer has conclusively shown that free oxygen does exist in the cell-sap§ in the normal condition. The importance of this matter for my purpose is that the move- Gesell.,’ 1886, p. 141), Bokorny (‘ Ber. d. Deutsch. Bot. Gesellsch.,’ 1888, p..116), who confirmed the above and proved the same for methylal, methyl alcohol, glycol, &e.; and Saposchnikoif (‘ Ber. d. Deutsch. Bot. Gesell.,’ 1889, p. 258). The organic acids cannot be employed with the same results (see Wehmer, op. cit., p. 713), though they can be absorbed and oxidised in the living cells (Warburg, op. cit., pp. 112— 113) more rapidly than they are decomposed outside the plant. * See Schimper, “ Unters. tiber die Entstehung der StarkekGrner” (‘ Bot. Zeiig.,’ 1881, p. 881); A. Meyer (‘ Bot. Zeitg.,’ 1880, Nos. 51 and 52). + For the general exposition, see Sachs, ‘ Lectures on Physiology of Plants,’ pp. 246—254, and the text-books quoted. Then Kohl, ‘Die Transpiration der Pflanzen,’ &c., Brunswick, 1886; Eberdt, ‘ Die Transpiration d. Pflanzen und ihre Abhangigkeit von diusseren Bedingungen,’ Marburg, 1889. The literature is col- lected by Burgerstein in ‘ Verhandl. d. K.K. Zool.-Bot. Gesell. zu Wien,’ vol. 37, 1887; vol. 39, 1889. £ See Godlewski’s explanation of the fine air-passages which run between the medullary ray-cells and place them in communication with lenticels (Pringsheim’s ‘ Jahrb. f. wiss. Bot.,’ 1884, pp. 569—630). § ‘Unters. a. d. Bot. Inst. in Tiibingen,’ vol. 1, p. 684, and “ Beitr. zur Kenntniss der Oxydationsvyorgiinge in lebenden Zellen” (‘Abhandl. der Kgl. Sachsischen Gesell. d. Wiss.,’ vol. 15, 1889, p. 449). Host and Parasite in certain Diseases of Plants. 407 ments of water, chiefly due to transpiration, but also incidentally caused by local decomposition, osmotic absorptions, d&c., are effective in bringing about aération of the tissues ; of course this aération (or ventilation) is not to be confounded with the movements of free gases, due to diffusion or to expansions or contractions due to changes of temperature.* These, then, are some of the changes which are continually and con- tinuously going on in the living cells of the normal plant. Of course I have not attempted any exhaustive list, or even a complete sketch of the structures and processes met with in living cells, the purpose being simply to bring prominently into view certain features of im- portance to the matter in hand. The Death of the Cell. The next point to consider is, what changes are observed when such cells as the above are killed. It appears to be of little moment ie. 5. A thin-walled parenchymatous cell killed by a few seconds’ immersion in water at 75°C. The protoplast contracts from the cell-wall, carrying with it the nucleus and chlorophyll-corpuscles, and allowing the cell-sap to escape; the thin cellulose wall consequently becomes lax, and suffused with cell-sap. A similar result is brought about by longer immersion in water at lower tempera- tures (above 5U° C.), or by very low temperatures, the action of poisons, &e. (Highly magnified.) * For further discussion, see Pfeffer, ‘ Pflanzenphysiologie,’ vol. 1, pp. 112—113, and the literature on transpiration. + On this subject cf. Frank, ‘Krankheiten der Pflanzen,’ 1880, pp. 12—15; Detmer, in ‘ Bot. Zeitung,’ 1886, No. 30; Pringsheim, in ‘Jahrb. f. wiss. Bot.,’ vol. 12, 1880 (pp. 47—-50 of the separate copy); also de Vries, ‘ Untersuch. mechan. Ursachen d. Zellstreckung,’ pp. 17—21. 408 Prof. H. Marshall Ward. The Relations between how the killing is brought about, so far as the final appearances are concerned. We may place the cell, for instance, for a few minutes in hot water (say 55—80° C.), or expose it to very low temperatures, or to the vapour of chloroform, to acid gases, &c., and in each case the morphological changes are substantially the same.* In the first place, the movements of the protoplasm cease, and the granulation increases, while the whole contracts away from the cell walls into a more or less shrivelled, irregular lump. The cell-sap, previously held in the sap-vacuolest under pressure in the turgescent living cell, now escapes, and suffuses the whole tissue, evidently because, the structure of the protoplasm being destroyed, it can no longer be kept in bounds as it was before. It would carry us too far to enter into the discus- sion as to what kind of changes the protoplasmic lining has undergone in its different layers; it suffices to note the fact that, whereas the living protoplasm was able to regulate the entrance of substances into the cell-sap and their escape from it, it is no longer able to do so when the cell has been killed, and the uncontrolled sap escapes as said. This sap is acid, often strongly so, and contains, among other things, certain bodies, known generally as chromogenes, which, on exposure to the air, undergo oxidation changes which result in the formation of brown colouring matters. We know very little about these chromo- genes beyond the fact of their existence, but the evidence goes to show that they are unstable bodies of various kinds which are present in the cell-sap under such conditions that they are not directly oxi- dised by the passive oxygen dissolved in the sap; on exposure to the air, however, some substance in the sap acts as an oxygen-carrier, and they undergo the change of colour referred to.f The consequence of this is that the disorganised protoplasm, cell walls, &c., of the tissues thus suffused turn brown, resulting in the well-known colours of dead vegetable tissues. These changes are accelerated by the organic acids, which cause the chlorophyll grains to turn yellow, and then suffer further changes from the oxygen of the air. Tt is, of course, unnecessary to remark that all the rhythmical series of processes connected with the living cell are now put an end to: respiration, metabolism, growth, assimilation have obviously ceased, as have all the other functions of the cell. Moreover, the evaporation of water is no longer controlled by the conditions imposed on it by * This, of course, without prejudice as to the sequence of molecular changes which bring about the final result. + See Pfeffer, ‘Osmotische Unters.’; de Vries, ‘‘ Studien tib. d. Wand d. Vacuolen,” &c., in addition to the foregoing. { See especially Pfeffer, “ Beitr. zur Kenntniss d. Oxydationsvorgiange in lebenden Zellen,’ pp. 447—454, where the older literature is collected. The remarkable behaviour of these substances in the cell-sap suggests how extremely complex every part (even the presumably simplest) of the organism of the cell must be, Host and Parasite in certain Diseases of Plants. 40% the protoplasm of membranes of living cells,* and if the weather becomes dry the dead tissues rapidly desiccate and shrivel. In attaining the above described extreme, commonly called death, the normal living cell, in the condition commonly called health, passes through a series of vicissitudes which affect every part of it; but it is necessary to admit that the state called death and that called life, in the above discussion, are by no means definite and utterly distinct from one another—on the contrary, the very essence of life consists in its mobility, and the living cell is continually approaching and receding from the state termed death. Ina certain sense, no doubt, death may be regarded as the cessation of life, but this does not help us, because the cru# resides in determining when life ceases in the protoplasm. Of course we can lay our hands, as it were, on given cells or tissues of cells, and say these are “living,” whereas others are “dead,” but the difficulty is to decide when the one state passes into the other. , Between normal life, 7.e., the condition of affairs where the life- processes are going on actively, and the state of permanent death, then, there are all possible gradations: many of these gradations «oincide with the phenomena of disease—pathological conditions—and it is towards this difficult domain that I have now to carry the discussion. Variations in the Environment as affecting the Physiological Processes in 3 the Host. In describing the phenomena going on in what was termed the normal, living cell, I only hinted at the fact that variations, more or less periodic in nature, occur in the intensity of the processes, a truth which at once shows the difficulty cf deciding what a normally living cell really is. But it is of the utmost importance to recognise that all the life-processes, and the changes dependent on them, are in their very nature variable. One set of factors which bring about the variations are internal and inherited, and very little is known of them beyond the fact of their existence, which is usually formally expressed by the admission that different plants differ in “constitution;” fortunately, this series of factors does not concern us at present, and it does not vitiate our general conclusions to assume that on the whole the differences in constitution between plants of the same Peers are so minute that they may be neglected. The second set of factors is of much greater importance, because __ they give rise to pronounced and easily recognisable changes in the * See Sachs, ‘ Physiologie Végétale,’ pp. 253, for proof that water evaporates less rapidly from living cell-surfaces than from dead ones, and for literature (my edition is the French one of 1868). VOL. XLYTI. 24 ‘ 410° Prof H. Marshall Ward. The Relotione beneeee plaut. These factors are such as the following: changes of tempera- ture, variations in the intensity of the light, differences in the amount of aqueous vapour in the atmosphere, &c., in short, the variable factors of the physical environment of the plant. That these affect the physiological processes in the cells is well known;* but what I have to do is to trace some of the effects, and show how they bring the living tissues into such conditions that they more or less readily resist or succumb to the attacks of certain parasitic fungi. Taking the more or less arbitrarily chosen but convenient headings. already employed—respiration, metakolism, growth, carbon assimila- tion, &c.—let us now see what kinds of effects the external agents. referred to may produce. Respiration, though it proceeds at very low temperatures,t is ren- dered considerably more energetic as the temperature rises, until, after a certain relatively high temperature (about 45° C.) is reached, it becomes less intense, and injury to the cells soon results, un- doubtedly from damage to the structure of the living substance, owing to the excessive disturbances brought about in its metabolism. Speaking generally, we may fairly say that at temperatures near 0° to 5° C. the respiration is very slow; as the temperature rises the respira- tory activity increases, at first slowly, and gradually more and more rapidly, till at 35° to 45° C. it is at its maximum intensity; beyond. that it rapidly declines, and ceases with the death of the protoplasm at about 50° C. Light appears to exert little or no effect on the normal process of respiration, unless relatively very intense,f when it may possibly promote it; but bright light may accelerate certain processes of oxidation which would otherwise have gone on more slowly.§ This much probably may be said, however: in so far as light influences. oxidation processes (other than respiration) in the living cell, the action increases with the intensity of the light.|| As we shall see * See Sachs, ‘Lectures on the Physiology of Plants,’ pp. 189—204, 299—308, 552—555, &c., for an introductory general account. The special literature will be noticed as we proceed. + See Kreussler in ‘ Landwirthschaftliche Jahrbiicher,’ vol. 16, 1887, and vol. 17, 1888, for the dependence of respiration on temperature. + Of course referring to ordinary daylight only. § See Pfeffer, ‘ Pflanzenphysiologie,’ vol. 1, p. 376, as to possible bearing of this on decomposition of organic acids (Pfeffer, “ Uber d. Oxydationsvorgiinge in leben. Zellen,” pp. 454, 469, 472). || As to the effect of very intense light, see Pringsheim, “ Ueber Lichtwirkung und Chlorophylifunction in der Planze”’ (‘ Jahrb. f. wiss. Bot.,’ vol. 12, 1880,. pp. 84—93). It should be remarked that Pringsheim not only shows that the action is really due to light- and not heat-rays, but that the more refrangible rays (blue, &c.) are the most active (see pp. 40 and 52). These and others of Pringsheim’s observations may be accepted without prejudice as to his theory of assimiiation. Host and Parasite in certain Diseases of Plants. 411 later on, there are some other remarkable changes going on in the cell, and connected indirectly with the action of light and respiration, but these do not probably affect the general conclusions just advanced, close as is the connexion between respiration and metabolism gene- rally. The question now arises as to the quantity of oxygen necessary for respiration, and as to the effects of undue accumulation of the carbon dioxide: it is too long a subject and it is unnecessary to discuss it in detail.* I need only remind you that in the absence of oxygen respiration ceases,} while it is interfered with when the amount of oxygen is much greater per unit of volume than in ordinary air, #.e., when the oxygen is condensed; under ordinary circumstances, how- ever, the free oxygen of the atmosphere amply suffices, provided it can pass readily into the cells and be renewed. Anything of the nature of stagnation must be assumed to impede respiration, whether simply from the accumulation of carbon dioxide, or other products of respiratory activily and consequent metabolism, or because sufficient oxygen-molecules do not pass into the protoplasm in a given time. Since the extremes are not nearly attained in nature, however, I pass by this subject with the remark that in proportion as the intercellular passages or other communications with the atmospheret become blocked by condensed water, for imstance,. the ventilation of the plant—and therefore its respiration—may suffer§ for the time being simply on account of the slower diffusion of the gases, carbon dioxide and oxygen, from one part of the piant to another. Coming now to the subject of destructive metabolism, we find that it is affected by external factors ; in the first place, by whatever affects respiration, and therefore the foregoing remarks apply to metabolism generally. This is especially so in the case of temperature, and the statements already given may serve broadly with respect to metabol- ism as awhole. A few details are of importance, however. We have * For further details, cf. the text-books already cited, e.g., Pfeffer, vol. 1, p. 377. + We are of course not concerned with so-called “‘intra-molecular’”’ respiration (cf. Pfeffer, vol. 1, pp. 370—374). t See Russow, “ Zur Kenntniss der Holzer,” &., in ‘Bot. Centralbl.,’ 1888 vol. 13, p. 136. § It is no uncommon event, even in England, to see the intercellular passages of leaves blocked with suffused water after a cold night, but the phenomenon is much commoner in the tropics, and occurs quite generaily in the hill country in Ceylon, for example. As the temperature rises during the morning, the water quickly evaporates and the leaf loses its dark, suffused, limp appearance, and becomes normal. Of course, the phenomenon is due to proportionally more water being absorbed from the relatively warm soil than the cool air can take up. See also Pfeffer, ‘Pflanzenphys.,’ vol. 1, p. 172, and the literature concerning the ascent of water in plants (collected in Marshall Ward, ‘Timber and some of its Diseases,’ 1889, pp. 59—141). Tie, 412 Prof. H. Marshall Ward. The Relations between spoken of two sets of bodies among the many which are produced during the metabolic processes of the cell—the organic acids and the amide-substances. It appears from the evidence to hand that organic acids are not only formed, but are also subsequently oxidised, in the cell, and it is only to be expected that this process of decomposition of the acids is also promoted by raising the temperature, and con- versely,* and such is the case; these acids increase during the night and diminish during the day, and one important factor in the pro- cesses is temperature. The optimum of increment of organic acids in the plant occurs at somewhat low temperaturest—e.g., about 10° C. to 15° C.; while the minimum coincides approximately with that of respiration (near 0° C.), and the acids cease to increase—or, rather, they are decomposed as fast as, or faster than, they are produced—as the temperature rises to 35—40°. With respect to the effects of light on metabolism, reference may be made as to what has already been said as regards its promoting certain processes of oxidation in the cells,f and to what follows on assimilation. The part played by oxygen also has been adverted to ; metabolism in the ordinary course of events depends on -respiration, and all that affects the latter affects it. In the absence of free oxygen, conditions of intense destructive metabolism are eventually set up, the details of which we need not discuss.§ If. plenty of non-nitro- genous food materials are present, the metabolism goes on for some hours as usual, but soon the starving protoplasm undergoes more and more profound changes, resulting eventually in a loss of proteid substances. It is important to bear in mind that.in the cells containing chloro- phyll the free acids diminish in daylight, and increase as the light fades and in darkness, no doubt because there is less oxygen in the absence of that set free by the chlorophyll corpuscles; these acids also decrease in proportion as the temperature rises, and increase as it falls. It is also important to be clear in this connexion as to the fact that two processes are going on simultaneously—on the one kand, organic acids are being formed as products of incomplete oxidation in the respiratory processes, and, on the other, they are being further oxidised and decomposed when the temperature is high and the light bright.|| Whether at any given moment the amount of acid present * See Warburg, ‘ Unters. aus d. Bot. Inst. zu Tiibingen,’ vol. 2, Heft 1, 1886, p. 102. + Warburg, op. cit., pp. 71 and 102, confirming the results obtained by de Vries (literature quoted). { See Pfeffer, ‘Ueb. die Oxydationsvorginge,’ &., pp. 419 and 454. § See, however, Palladin, “‘ Ueber Eiweisszersetzung in den Pflanzen bei Abwesen- heit von freiem Sauersioff”’ (‘ Ber. d. Deut. Bot. Gesellsch.,’ 1888, p. 205). || Mhat the connexion with light depends on the access of oxygen set free in” Host and Parasite in certain Diseases of Plants. 413 is larger or smaller depends on the resultant action of these processes. Anything which interferes with oxidation promotes the accumulation of organic acids, whereas those changes which lead to increased oxidation in the cells are followed by a decrease of acids. Now a few words as to growth, and its dependence on external factors. Apart from the thickening of the cell-walls, which comes afterwards and depends on the addition of materials formed by the protoplasm,* the principal phenomenon that concerns us is the exten- sion of the cellulose membranes. This process is promoted by moderately high temperatures, and retarded by low ones and by very high ones,} in accordance with respiration and the general metabolism of the cell; the curves are not quite the same, because respiration begins at temperatures too low for growth, and goes on rising in intensity to temperatures at which growth begins to decline; still the connexion is very close, and the dependence of growth on respiration and metabolism implies this. Light is usually considered to have a retarding effect on the growth of the cells. Apart from the possibility that there may be a more direct action of light on the extensibility of cell-walls or of cells generally, by its effects on the protoplasm at the spot, one way in which this retarding effect may be brought about is in connexion with the turgidity of the cells. Without concerning ourselves with the general discussion of the whole subject, which would be a very long one, it seems, at least, clear that in the ordinary course of events light exercises some retarding action on growth by exten- sion; what, if any, connexion exists between this phenomenon and the observed diminution of the organic acids in the cells (and we have seen that their turgidity depends on these acids and their salts) in daylight still needs investigation, and the same may be said as re- gards the influence of temperature in relation to growth and the production of acids. It is customary to regard the retarding action of light on the extensibility of the cell-wall as a complex phenomenon - of irritability,t and it is by no means certain that such is not the case; meanwhile we simply accept the facts that in ordinary bright light the extension of.the growing parts is retarded, that this is connected with diminished turgidity, which in its turn is depen- ' dent on the pressure in the sap of substances capable of retaining the carbon assimilation, and not on any direct action of the rays of light, can hardly be doubted (see Warburg, op. cit., pp. 77—92). * For details see Strasburger, ‘ Uber den Bau und Wachsthum der Zellhaute ’ and “Ueber das Wachsthum yegetabilischer Zellhiute” (‘Histologische Beitrage,’ No. 2, 1889). ¥~ Sachs, ‘ Physiology,’ pp. 194 and 558. { See Vines, ‘ Physiology of Plants,’ p. 398; but cf. also Wortmann, ‘ Bot. Zeitg.,’ 1887, Nos. 48—51, especially col. 808—810. 44 Prof. H. Marshall Ward. The Relations between necessary water. If we accept, with de Vries,* that these substances are chiefly the organic acids and their salts, then we may expect the study of influence of light in promoting the decomposition of organic acids in the plant to give more information on these matters. The same remarks apply with regard to the influence of variations in tem- perature. Growth is, of course, impossible without water, and the transpira- tion current supplies this to the osmotically active cells. In nature, the quantity of water at the disposal of these cells varies enormously, not only with the quantities at the disposal of the root-hairs, but also with the rapidity of the transpiration influenced by the atmosphere. On the whole, given favourable temperature, and other circumstances, growth in length is mest active in damp weather, when the quantities of water in the cells are relatively very large ; it is retarded in hot, dry weather, because the loss of water is sufficiently extensive to diminish turgidity. Passing now to carbon assimilation, I come to the subject which offers most interest for our enquiry. Assimilation is also to some extent influenced by temperature, although in a very different manner from respiration; and the influence of even large variations in temperature may be masked by the effects of small variations in other factors, especially light. Assimilation takes place at low temperatures whenever respiration is possible, but the temperature curve for assimilation in ordinary bright sunlight is steeper than that for respiration, and at higher temperatures (say, 30° C. and above) where respiration is not yet most active, assimilation is already beginning to decline. In the blackberry, for instance, whereas assimilation is most active at between 29° and 33° C., re- spiration goes on becoming more and more energetic to 46° C., at and beyond which its effects are of course dangerous to the plant.{ On the whole, we may conclude that at low temperatures, say, 5° to 10°C , on a bright spring morning, assimilation is relatively more active than respiration, whereas at higher ones—30° to 40°—the reverse is distinctly the case. The effects of variations in the intensity and kind of light on assi- milation have been much studied, and may be summed up generally for our purposes as follows. With ordinary solar light, as it reaches the plant on a clear day in the open, the activity of assimilation increases nearly in proportion to the intensity§ of the light; this is usually expressed by saying, the * “Unters. tiber d. mechan. Ursachen d. Zellstreckung,’ 1877, and ‘ Bot. Zeitg.,’ 1879, col. 848. + See Kreussler, ‘ Landwirthschaftl. Jahrb.,’ vol. 16, 1887, and vol. 17, 1888. t See Kreussler, loc. cit., 1887, p. 746. § The word must not be pushed too far as to meaning, in the absence of any satis- Host and Purasite in certain Diseases of Plants. A415 Comparison of temperature — curves for Wesyrratvon and Assimilation wn the Blackberry (Lreussle a) in sya rattore dssemalation 2.3 25° 7.5° 113° 15.8° ; O° “29:5.35,0 3733" LM Gt s Centiyi ade. Fie. 6. Diagram constructed to show the comparative effects of equal increments of temperature on respiration and assimilation respectively, according to Kreussler’s data. The base line has marked off on it a number of intervals corresponding to so many degrees centigrade, as denoted by the figures; on the ordinates from these points are measured distances corresponding to Kreussler’s figures—numbers representing the comparative intensity of the functions in question, if that at the lowest observed temperature is taken as unity. more light the plant can get, the better. There is evidence to show that, as might be expected, light of great intensity concentrated by means of a lens, &., on to the assimilating apparatus, produces de- structive pathological changes ; but we may also infer from everyday experience with shade-plants (e.g., camellias) that the light may be too intense for normal assimilation to go on,* and such is the case. | Another point of importance is the kind of light which reaches the factory mode of Soa “brightness,” “ (see Sachs, ‘ Phys.,’ pp. 301—302). * See Famintzin, ‘ Bull. de l’ Académie de St. Pétersbourg,’ vol. 26, 1880, col. 296 — 314, Also Reinke, ‘ Bot. Zeitg.,’ 1883, No. 42, with literature. intensity,” ae &e., of light PS Sote Pee 446 Prof. H. Marshall Ward. The Relations between ‘plant. I need not remind you that some rays of the solar light, especially some of the less refrangible (orange and red) rays, are more concerned in the process of assimilation than others, and, although we -zannot here stop to discuss this matter in detail, I may point out that, as different rays of light are absorbed or reflected in the atmosphere, we may have variations in this connexion of more or less importance tothe plant. The experience of photographers shows that the different ‘thicknesses of the atmosphere through which the light has to pass, ‘reflection from a cloud as contrasted with the “ blue sky,” &., all -exert influence on the composition of the light, and in prolonged ‘cloudy, dull weather or fogs this factor may add its effects to those ‘due to the mere dilution of the light as a whole. _ But the fundamental nature of the necessity for a suitable intensity ‘of light of the right composition is best brought out in studying the effects of low intensities of light on the green organs of plants. *, As is well known, the general effect of keeping a plant in the dark is to induce a condition known as etiolation.* The whole plant: becomes pale yellow or colourless, and has a curiously trans- lucent, watery appearance; the internodes are excessively long, while the leaves, on the contrary, are usually small and crumpled. Closer investigation shows that each cell of the internodes is abnormally elongated, its cell-wall thinner than usual, and its chlorophyll corpus- cles small and wanting the green chlorophyll. Jf we examine the vascular bundles, they are found to be deficient in firmness, because the substances which normally go to thicken their walls have not been forthcoming. Everything about the etiolated shoot indicates tenderness, and as amatter of fact such shoots are very ill-adapted to withstand the ordinary exigencies of plant life. Undoubtedly the chief cause for this weak condition is the absence of the light necessary for the purposes of assimilation ; the carbon dioxide may be present, and even the fully green chlorophyll could be developed by a few hours’ exposure to feeble light, but these do not suffice for the construction of the materials such as giucose, starch, &c., necessary to enable the protoplasm to keep the tissues normal. | Nevertheless, the other functions of the cell are being carried on with remorseless pertinacity. The oxygen of the air enters the pro- toplasm, establishes its usual combinations, and carbon dioxide and water are given off to the air. The chemical changes known collec- tively as metabolism proceed, and result in the addition of substances. to the cell-sap which were not previously there. To an extent more marked than ever before, the turgid cells may be elongating, and this * See Sachs (‘ Bot. Zeitg.,’ 1863, supplement, and 1865, col. 117, &c.); G. Kraus (‘ Jahrb. f. wiss. Bot.,’ vol. 7, p. 209; Godlewski (‘ Bot. Zeitg.,’ 1879, col. 81) ; de Vries (‘ Bot. Zeitg.,’ 1879, col. 852) ; Godlewsk ( Biol. Centralbl.,’ 1889). ¥ Host and Parasite in certain Diseases of Plants. AIT brings us to note that the key to the condition of affairs is the fact: that the dry weight of the etiolated shoot is decreasing: every molecule of carbon dioxide which comes away lessens the dry organic substance of the plant, and no restoration of such substance is possible in the absence of light. In other words, then, the etiolated plant is growing to death, at the expense of what organic carbon-compounds it possessed at the begin- ning. Assimilation is, of course, profoundly affected, like every metabolic process, according to the relative amounts of oxygen and carbon dioxide in the air, and although it never happens in nature that the extremes are approached, nevertheless experiments on this subject have led to interesting results.* The quantity of water present in the plant and its atmosphere and the rapidity of the transpiration current undoubtedly affect tlie process of assimilation in a high degree. Not only is water needed for the molecular processes concerned in the act of assimilation, and not only does the supply of materials to the protoplasm depend mainly on the transpiration current, but, as we have seen, the aération of the intercellular passages, and consequently the move- ments of gases generally are affected. Té has long been known that the quantities of carbon dioxide absorbed, and of oxygen evolved, in the process of assimilation, vary with the age of the leaf or other organ concerned, and Kreussler has. shown that one reason for these variations is the quantity of water present in the tissues at the time. In fact, an essential cause of variations in assimilation exists in the differences in the water contents of the tissues,f and it is no doubt largely due to the want of water that older leaves assimilate so unequally—they are unable to. rapidly restore the equilibrium between losses and gains when it is» seriously disturbed. | As for transpiration itself, and all the movements of water cor- related with it, it is well known that the various factors of the environment affect it profoundly. Apart from the more obvious relationst between transpiration and the temperature of the atmosphere, and the quantity of aqueous. * See Godlewski, “ Abhangigkeit der Stirkebildung in den Chlorophyllkérnern von dem Kohlensiuregehalt der Luft” (‘ Flora,’ 1873, p. 878) ; also in ‘ Arb. des Bot. Inst. in Wurzburg,’ 1873, vol. 1, p. 343. Further, Pringsheim, ‘‘ Ueber die Abhangigkeit der Assimilation griiner Zellen von ihrer Sauerstoffathmung,” &c. (‘Sitzungsber. d. Kgl. Preuss. Akad. der Wiss. zu Berlin,’ 1887, No. 38, pp. 763— 777). + Kreussler, “ Beobachtungen tiber die Kohlensiure-Aufnahme und -Ausgabe- der Pflanzen,” II (‘ Landwirthsch. Jahrb.,’ vol. 16, 1887, especially pp. 728—30). f See the text-books referred to, especially Pfeffer, ‘ Pflanzenphysiologie,’ vol. 1,. pp. 146—150. at te Sea 418 Prof. H. Marshall Ward. The Relations between vapour in it, it must be borne in mind that many events concur in promoting or retarding it. The stomata, for instance, open widely in bright sunshine and close in the dark,* a matter of great importance in controlling transpiration, as must be concluded from the researches of Garreau and von Hohnel.t Other effects are traceable to the influence of the wind shaking the plant, and to the quantities of mineral salts, é&c., in the soil, but it would carry me too far to discuss further instances. The principal feffects of obstructed transpiration may be shortly compared with those due to want of light—the watery tissues are strikingly like those of an etiolated plant, and we may look upon a shoot growing in a saturated atmosphere as presenting all the chief features of one growing in darkness.{ Its cells are extremely turgid, with watery, soft, thin walls, and acid cell-sap; its vascular bundles feebly developed and hardly lignified ; and, as before, it is ill adapted to withstand the exigencies of the ordinary environment. All such plants or organs are, so to speak, in a permanently young condition. The Effect of the Preceding Variations in “ Predisposing” the Host to Disease. If we put together the results of the preceding discussion, it is evident that a plant may vary within very wide limits of the con- dition we term health. No doubt this needs no proof to the minds of most of my hearers, but the point I wish to emphasise is that, in some of its deviations from the normal, the plant offers conditions to an attacking parasite which may be at one time favourable, at another not. Suppose the case of a herbaceous plant growing under the follow- ing circumstances in July: the temperature has been high, and the daily supply of solar light abundant during the previous four or five weeks, and everything has been going on admirably, so far. Suddenly the weather changes—the temperature falls, rain sets in, and for many days heavy clouds obscure the sun. If this markedly different, dull, cold weather continues, we may have the following condition of affairs more or less realised, as is well known to those who observe cultivated plants closely. - epee Transpiration being lowered in activity, the whole plant tends more -and more to be suffused with water; the stomata are nearly closed, * See Sachs, ‘ Lectures on the Physiology of Plants,’ pp. 248—250, and Stras- ‘burger, ‘ Das Botanische Practicum,’ 2nd ed., 1887, pp. 88—90. t+ See Pfeffer, ‘Pflanzen-Physiologie,’ vol. 1, p. 144. { Vesque and Viet, “ Influence du Milieu sur les Végétaux’’ (‘ Ann. d. Sci. Nat.,’ ‘6 Sér. (Botanique), vol. 12, 1881, p. 167). Fost and Parasite in certain Diseases of Plants. 419 the cell-walls bounding the inter-cellular passages and the air in the passages themselves are thoroughly saturated with water and aqueous vapour respectively, and the movements of gases must be retarded accordingly, turgescence is promoted, and the water contents accumu- late to a mavimum, owing to the disturbance of equilibrium between the amounts absorbed by the active roots in the relatively warm soil and those passing off into the cold damp air; much more water is absorbed by the roots in the relatively warm soil than passes off as vapour in equal periods of time. An enhanced wateriness of the whole plant, then, is one result. But the low temperature, feeble light, and partially blocked ventilation system have for a consequence a depression of respiratory activity and the absorption of oxygen generally. Hnough oxygen gas finds its way slowly into the cells to keep the life-processes going, of course, but not enough to complete the oxidations and decompose the organic acids, at the prevailing low temperature, so rapidly as before,* and thus another consequence is a tendency to the accumula- tion of organic acids. According to de Vries, however, the increase of organic acids must make itself effective in enhancing the turgidity of the cells, and no doubt it does so to a certain extent; beyond a certain point, however, it is more likely to increase the permeability of the protoplasm,t and we may even suppose small quantities of the acids to filter out even to the watery cell-walls.t Partly due to the low temperature and the depressed gas-inter- change, but far more owing to the feeble light, the process of assimilation will be less active than previously. This will not be immediately felt if, as will probably be the case, there are large quantities of temporary reserves in the leaves and internodes; but it may react indirectly on the processes of oxidation and respiration, inasmuch as less free oxygen is evolved in the cells than would be the case in bright weather. As the temporary stores of starch dis- appear, however, the cells become more and more surcharged with glucose, together with organic acids, and it depends on several circum- stances, especially on how rapidly growth is going on (e.g. m the parts below ground), whether this glucose in solution passes away, or is used up slowly or rapidly; if it cannot move, or only extremely slowly, then we have the case of tissues surcharged with water con- taining organic acids and glucose in solution. It may be surmised * See Warburg, op. cit., especially pp. 73—77, and 126. +. See Pfeffer, “‘ Ueber Aufnahme von Anilinfarben in lebenden Zellen,”’ in ‘ Unters. a. d. Bot. Inst. zu Tibingen,’ vol. 2, 1886, pp. 296 and 329, for proof that dilute acids ae traverse without permanently injuring the protoplasm. t Pfeffer showed, for instance, that methyl-orange, after being taken up in the Bite cell and held there by the protoplasm, can be made to diffuse out again e a little citric acid is imbibed (“ Ub. Aufnahme,” &c. , op. cit., p. 293). 420 Prof. H. Marshall Ward. The Relations between that the increased amount of organic acids is favourable rather thaz otherwise to the ferment processes which lead to the conversion of the starch into glucoses.* How far the protoplasm will allow the watery solution of glucose to escape, owing to its increased perme- ability, cannot be determined, but it is at least probable that some may reach the cell-walls. In any case, we have the cells flooded with a dilute solution of organic acids and glucose, and the controlling protoplasm becoming less and less capable of retaining the excess. The turgid condition of the cells, and the diminished intensity of the light, will favour growth, and, in spite of a comparatively low temperature, the organs may be extending more or less rapidly or ‘slowly. If so, the tendency will be for the very watery cell-walls to become relatively thinner than usual, as well as watery, because the ill-nourished protoplasm does not add to the substance of the wall in proportion. This being so, we have the case of thinner, more watery cell-walls acting as the only mechanical protection between a possible fungus and the cell contents. But this is by no means all that has to be considered, when the conditions remain as above described. Sooner or later the glucose begins to fail, either because it has been directly employed for the support of the metabolic processes in the protoplasm in the immediate neighbourhood, or (less probably) because it has been re-converted into starch,t or other reserve carbohydrates by the leucoplasts in the cells of the roots, tubers, &c., at a distance. Now, as soon as a want of carbohydrates makes itself evident in the destructive meta- bolic processes accompanying growth, the accumulation of substances like asparagin, leucin, &c., is apt to occur,§ as products of the de- composition of the proteids. Under more normal conditions, as we have seen, these amide-bodies would be worked up again with carbo- hydrates into new constituents of living protoplasm, but they now begin to accumulate. The net result of the foregoing changes amounts, shortly put, to the following:—Under certain circumstances the parenchymatous tissues of the living plant may be in a peculiarly tender, watery condition, where the cell-walls are thinner and softer, the protoplasm * Baranetzky, ‘Die Stirkeumbildenden Fermente,’ 1878; Brown and Heron, ‘Journ. Chem. Society,’ 1879; Detmer, ‘Das Pflanzenphysiologische Praktikum,’ 1888, p. 198. + So far as the composition of the light is altered, it will probably favour growth, because the more refrangible rays are fewer when the light has to traverse a thick ee ft See Schimper, ‘ Bot. Zeitg.,’ 1880, col. 881; and A. Meyer, ‘ Bot. Zeitg.,’ 1880, Nos. 51 and 52. § See Palladin, ‘ Ueber eee ae in den Pflanzen” (‘ Ber. d. Deutsch. Bot. Gesellsch.,’ 1886, p. 205) ; and for older literature, Pfeffer, ‘ Pflanzenphysiologie,” vol. 1, pp. 298—301, and further literature quoted. Host and Parasite in certain Diseases of Plants. 421 is more permeable and less resistant, and the cell-sap contains a larger proportion of organic acids, glucose, and soluble nitrogenous materials than usual. When the external conditions become more favourable—the temperature higher, the air drier, and the sunlight more powerful—increased transpiration and respiration lead to more normal metabolic activity, for which energetic assimilation provides the materials. Of course, all kinds of combinations are possible in detail, but when dull, cold, wet weather prevails for some time, after a period of bright, hot, and dry weather in the early summer, we are very apt to have herbaceous plants in such a condition as that sketched. | This being so, I have now to show how the chances of a suitable fungus are increased, if it happens to start its parasitic life on such a host in such a condition. Bobsyts and other Fungi as Agents of rica and their Dependence on the Condation of the Host Plant. Let me first proceed to call your attention to a parasitic disease of a very extraordinary kind, though caused by a fungus belonging to a well-known and widely-spread family. This disease, and the fungus in question, may be met with in nearly every garden and greenhouse all the year round, and is quite common in the open fields and lanes of this country and elsewhere in Hurope. In the form generally met with, the fungus has been placed in a separate genus known as Botrytis, though, in the few cases that have been thoroughly worked — out, it has been proved that the mould-like Botrytis is only the conidial form of certain higher ascomycetous fungi belonging to the Pezizas, and which egree in developing sclerotia. As we are not con- cerned with the details of the whole life-history of this group, I shall purposely avoid further reference to the higher stages of development, confining our attention chiefly to the Botrytis stage.* On dead and dying leaves, twigs, fruits, &c., of plants from all parts of the world, in the open and in greenhouses, in Europe and elsewhere, there is often to be observed an ashen-grey mould, super- ficially not unlike the Phytophthora of the potato-disease. It appears under various slightly different aspects as regards the shade of colour, the length and degree of branching of the conidiophores, and the size and shape of the conidia, and many different species have heen figured and described, some good, many bad, according to the variations in colour, size, &c., referred to, and the substratum on which the mould is found growing. It sometimes happens, however, ean this same mould is found * For further details as to the morphology, &c., ef. de Bary, ‘Comp. Morph. and Biology of the Fungi,’ &c., especially under the heading Peziza Fuckeliana. 422 Prof. H. Marshall Ward: The Relaticns between Fie. 7. A dead leaf infested with moulds, especially with Botrytis, as shown on the grey patches. (Natural size.) spreading more or less rapidly from dead and dying parts of a plant to the assumed healthy organs, and it has been customary to look upon this as a secondary phenomenon due to the “ dying-off ” of the adjoin- ing parts, the fungus spreading to them as they died. No one questioned the saprophytic nature of the Botrytis,* and so the matter _stood for a long time. Gradually, however, it came to light that various forms of this Botrytis appear as phases in the life-history of certain sclerotium-bearing Pezizas which were associated in a manner suspicious, to say the least, with epidemic diseases of rape,f clover,{ hemp,§ onions,|| hyacinths (also Scilla, Narcissus, Anemone, &c.), balsams,** Carex, rice, and many other plants. Further, this mould was found causally associated with the rotting * Of course I am referring to the modern definition of the genus Botrytis, after its separation from the totally different Peronosporee (see ‘ Annals of Botany,’ vol. 2, p- 357). t+ See Coemans in ‘ Bull. Acad. Roy: de Belgique,’ Sér. 2, vol. 9, 1860, p. 62; and Frank, ‘ Krankheiten der Pflanzen,’ 1880, pp. 581—537. ft Kihn, ‘ Hedwigia,’ 1870, No. 4, p. 50; Sorauer, ‘ Pflanzenkrankheiten,’ vol. 2, 1886, pp. 283—288; Rehm, ‘Die Tinbwickelumeesoseh ea eines die Hilecarten zerstorenden Pilzes,’ Gottingen, 1872. § Tichomiroff, in ‘ Bull. Soc. Nat. de eee 1868, 2 (see Hoffmann’s ‘ Mykol. Berichte,’ 1870, p. 42). || See Frank, op. cit., p. 540, and Sorauer, ‘ Oesterr. Landwirthsch. Wochenbl.,’ 1876, p. 147, and ‘ Pflanzenkrankheiten,’ vol. 2, p. 294. 4 Meyen, ‘Pflanzenpathologie,’ 1841, pp. 164—172; and Wakker, in ‘ Bot. Centralbl.,’ 1883, vol, 14, p. 316. ** Frank, loc. cit., p. 544. Host and Parasite in certain Diseases of Plants. —- 423: of many fruits, such as pears and apples,* grapes, cranberries,t &., and on chestnuts.§ In short, even the forms of Botrytis which were most persistently regarded as saprophytic have now been shown to: enter living plants and cause parasitic diseases in them,|| and com- plaints of such epidemics are occasionally heard from various parts,, as a rule, however, the disease is sporadic, and I now proceed to: describe its symptoms. Fie. 8. A bunch of “mouldy” grapes infested with Botrytis’ cinerea. The: ravages of the fungus cause the skin to rupture, and the fruits to shrivel from loss of water ; other changes in the substance of the contents are referred to in the text. Patches of the conidiophores are seen on the exterior (Miller- Thurgau). Small reddish-brown spots appear on the leaves, pedicels, ripening frnit, or other organ attacked; these enlarge and spread, and the. parts turn brown, shrivel up, and rot off or dry up, according to the state of the weather. In some cases the whole plant gradually turns. * Sorauer, ‘ Pflanzenkrankheiten,’ vol. 2, p. 298. + See especially Miller-Thurgau, in Thiel’s ‘ Landwirthsch. Jahrb.,’ vol. 17, 1888, pp. 83—160, on “ Hdelfaule.” ~ See especially Woronin, ‘Mém. de I’Acad. de St. Pétersb.,’ vol. 36, No.” 6,, 1888. § Kissling, ‘Zur Biologie der Botrytis cinerea,’ Bern, 1889, p. 14 (where also the literature is collected). || #.g., B. cinerea, the conidiophores of Peziza Fuckeliana (see de Bary, ‘Comp. Morph. and Biol. of Fungi,’ p. 380), is now known to beZcapable, of producing. epidemic diseases in vines, gentians, &c. —. ae cr ll uae ha \ A424 Prof. H. Marshall W ard. The Relations between yellow and dies, more often only a part of it goes,* and in many cases the disease is confined to individual organs—leaves, flower-buds, fruit, &c., as the case may be. When the disease occurs amongst stored chestnuts, carrots, parsnips, &., the tissues become speckled, and in many cases this spreads till they are rotten throughout; and similarly with stored bulbs, corms, and tubers, &e. Wherever the disease is rampant we find the colourless, septate, branched fungus. mycelium in the dead and dying tissues, and usually emitting hyphe, which grow into the damp air and bear the conidia in abundance. In some cases, however, these aérial conidiophores have not been observed,t and the habit of producing them appears to be lost, though in every other respect the behaviour of the mycelium is the same in all the cases thoroughly examined. Fie. 9. Botrytis cinerea. The upper figure represents a tuft of the conidiophores breaking through the epidermis of a grape (magnified) ; the lower one is one of the conidiophores still more highly magnified. Some very remarkable facts have come to hight during the last few years concerning this mycelium and the conidia; and as all the species or forms which have been thoroughly examined agree essen- tially in their physiological behaviour, I need no longer trouble you * A curious fact is sometimes observed—the small brown spot suddenly ceases to spread, and the hyphe may be found in it in a dried-up, dormant condition for weeks. See also ‘ Annals of Botany,’ vol. 2, 1888, p. 356, and figs. 51—54. + £.g.,in de Bary’s Peziza Sclerotiorum (Lib.). See “ Sclerotinien und Sclero- tinien-Krankheiten”’ (‘ Bot. Zeitg.,’ 1886, col. 424). i i ae eee Ce BR 6 ie ae Host and Parasite in certain Diseases of Plants. 425 with references to any special forms, excepting in so far as the cita-: tion of authorities necessitates this. In the first place, the mycelium and conidia are not only capable of erowing and flourishing in artificial nutritive media, but they often refuse to do otherwise—at least while young. If the conidia are sown in such media as the juice of grapes or other fruits, or in solu- tions containing an organic acid, sugar, asparagin, and traces of mineral salts, enormous cultures may be made for weeks, and millions of new conidia, sclerotia, &c., obtained, provided certain conditions are fulfilled. Among these conditions are the following :—The temperature must not be high, and may oe relatively low (best about 5°.C.); the solution must not be alkaline or neutral, but should be somewhat acid ;* sugar of some kind—and preferably a glucose— must be present; and the nitrogenous materials may be offered as asparagin or peptone with aera. It will be noted that just those external climatic conditions wition we have seen to be disturbing to the well-being of the green host- plant are either favourable to the fungi we are concerned with, or are at any rate not in the least inimical to their development. | Thus the oxygen respiration of the fungus goes on at all tempera- tures from 0° C. to 30° C. and higher, and, aléhingo we still want information as to details, experiments have shown that the mycelia flourish at temperatures considerably below the optimum for higher plants. Moreover light, so indispensable for the carbon assimilation of the green host, is absolutely unnecessary for the development of the fungus.{ Then, again, the dull, damp weather and saturated atmosphere, so injurious to higher vegetation if prolonged, because they eniail inter- ference with the normal performance of various correlated functions, as we have seen, and render the plant tender in all respects, are dis- tinctly favourable to the development of these fungi. Consequently the very set of external circumstances which make the host-plant least able to withstand the entry and devastation of a parasitic fungus like Botrytis, at the same time favour the oes ment of the fungus itself. As already said, it had long been assumed that these forms of Botrytis are saprophytes, and the ease with which they may be culti- * See Marshall Ward, “A Lily Disease” (‘ Annals of Botany,’ vol. 2, 1888, p. 334) ; also cf. de Bary (‘ Bot. Zeitg.,’ 1886, col. 400). + See also Hoffmann (‘Jahrb. f. wiss.- Bot.,’ vol. 2, 1860, p. 267) and Zopf. 3 ewe der Naturwiss.” (Schenk’s ‘ Handbuch,’ vol. 4, 1889, pp. 471—472). + According to Klein (‘ Bot. Zeitung,’ 1885, col. 6), the conidia of Botrytis cinerea batdsly developed i in the a of night, but this is certainly not the case with other species. VOL. XLVII. 21 426 Prot. H. Marshall Ward. The Relations between veted in artificial solutions, as above, tended to support that view : moreover, many attempts to directly infect living plants with the conidia failed—the conidia, if merely placed in a drop of water on a healthy leaf, simply germinated and died, and very often nothing more came of it. Nevertheless, odd instances of infection were recorded here and there, and the whole matter became a great puzzle,* until several points of startling importance came to light. In the first place it turned out that, although the germinal tubes of certain of the Peziza-forms could not penetrate into the living leaf of the host directly—whereas they plunged forthwith into the tissues of a dead organft—neyvertheless the myceliwm developed from such spores, provided it was vigorous and well nourished by previous culture as a saprophyte, could do so, but in many cases only provided the tissues of the host were in a favourable condition. This last proviso was found to be necessary, because in some cases the my- celium easily infected young growing internodes, &c., but could not penetrate into the more fully developed older parts of the same plant. This threw some light on the curiously capricious behaviour of the fungus in green-houses, where seedlings, cuttings, young internodes, &c., were often attacked and destroyed, while older parts escaped, though without any regularity of behaviour. The key to the mystery appeared to be offered when it was dis- covered that the invigorated mycelium, well nourished by cultivation in a solution such as that mentioned above, excretes a ferment which possesses the power of swelling and dissolving cellulose, and that this ferment is formed at the tips of the hyphe,§ and thus enables them to enter the cell-walls, as they were actually seen todo. It becomes intelligible now why these hyphe sometimes can and sometimes cannot quickly enter the cell-walls.of a plant: when the cell-walls are thin and watery, and especially if small quantities of organic acids are present, the fungus hyphe can easily attack and dissolve them, but in cases where they are thick and tough, owing to paucity in water and no traces of acids, the hypha has no chance. Just such differences as these would occur in the case of young and old organs respectively, or of partially etiolated or thoroughly matured tissues respectively. But in addition to piercing the walls, and ‘at first living in the * We shall see that the occasional infection depends on (1) condition of host, (2) whether any soluble food-materials pass from the leaf into the drops of water, and (3) the state of the conidia. f See de Bary, “ Ueber einige Sclerotinien und Sclerotinien-Krankheiten” (‘ Bot. Zeitung,’ 1886, col. 410). ; ft See de Bary, ‘ Bot. Zeitg.,’ 1886, col. 440—441. § See Marshall Ward, “A Lily Disease” (‘ Annals of Botany,’ vol. 2, pp. 389— 348). Host and Parasite in certain Diseases of Plants. 427 Fig. 10. Portion of a transverse section through an infection-spot in the tissues of snowdrop (such as that at @ in fig. 11), showing the swollen cell-walls with hyphe of Botrytis in them. The cell-contents also show changes ; the proto- plasm contracts, dies, and turns brown, and stains less and less readily the further the changes proceed ; the cell-sap escapes and suffuses the cell-walls ; the nucleus is the last to succumb. The above changes are exhibited by cells some distance away from the hyphe, and are the less pronounced the further away the cells are. The colour reactions are of course not reproduced. (Very highly magnified.) cellulose substance,* the hyphe also excrete a soluble substance which kills the protoplasm (with which they are not in contact) of the cells in the immediate neighbourhood: whether this substance is a separate zymase, or whether it is the same soluble ferment as that which swells the cellulose, is not clear, or whether the protoplasm simply dies after excessive plasmolysis due to water passing into the swollen walls, but it is clear that some such poisonous action is exerted at a little distance from the tip of the hypha, and therefore by means of a soluble poison or zymase of some kind. It is difficult to decide what this poison is, and the following questions arise:— first, Is the poison the same zymase as that which causes the swelling and solution of the cellulose? This must be denied pro- visionally, at any rate, because if sections of the tissues are put into solutions containing extracts of the mycelium which have been pre- viously boiled for a minute or two, the protoplasm contracts and dies much as before, though the cellulose walls no longer swell as before because the zymase has been killed by the boiling. This experi- ment_is not quite conclusive, because the contraction of the proto- plasm may be due to the action of bodies in the boiled extract which did not exist in the freshly expressed liquid.+ * See ‘ Annals of Botany,’ vol. 2, p. 356 and figs. 55 and 56. + De Bary inclined to the belief in a special ferment in the case of his Peziza (Joc. cit., pp. 418—420), but admitted that he had not proved the point either way. . a ie 428 Prof. H. Marshall Ward. The Relations between The next question which arises is—Is there any definite body in the extract that could kill the protoplasm, and which would not be destroyed by the short boiling? The answer to this question is simple: the hyphe of the fungus develop large quantities of oxalic -acid* in the substratum, and this is a substance which is peculiarly poisonous to the living protoplasm of higher plants} if present in any large quantity. In the normal cells of plants rich in salts of oxalic acid (Ozalis, Begonia, &c.) I need only remind you that the acid is not in the protoplast, but is kept strictly isolated from it by the vacuole wall, as is clear from the researches of Pfeffer and De Vries. It is at least conceivable, therefore, that the hyphz kill the cells by flooding the protoplasm with oxalic acid; but it is not certain that they do not excrete a more subtle poison of the nature of a ferment. _ In any case, it is a significant fact that the hyphe kill the cells by emitting some soluble poison which causes the protoplasm to collapse, and then to turn brown, clearly because it destroys its power of re- taining and restraining the sap in the sap-cavity; the latter there- fore escapes through the now permeable dead or dying protoplasm, and owing to its acid contents, chromogenes, &c., stains it and the cell-walls brown as the oxygen of the air enters into combination. There is thus, from the very first, a struggle between the hypha of the fungus and the cells of the host; the hypha is in the position of an attacking party, which has to overcome, first the outworks, in the shape of cuticle and cell-wall, and secondly the real fighting foree— the protoplasm. I take it that the attacking hypha (invigorated by previous culture, as said) excretes various zymase-like substances formed in its metabolism; one of these succeeds in overcoming the resistance afforded by the cuticlet and then the cell-wall is penetrated : the partially victorious hypha then advances in the cell-wall, and is nourished by the cellulose which it goes on dissolving, and under its changed conditions of life excretes in increasing quantities yet another zymase or some kind of poison which diffuses to the protoplasm. Now comes the real tug of war—so long as the outer layer of the protoplasm (the ectoplasm) is in a position to refuse access to, or in any way to destroy, the poison, the rest of the protoplast remains impermeable, and the hyphe keep to the cell- * De Bary observed the same in the case of Peziza sclerotiorum (op. cit., pp. 399 —403), and it is a common phenomenon in fungi. See, e.g., Zopf (Schenk’s ‘ Handb.,’ vol. 4, 1889, p. 454). + See de Vries, ‘‘ Plasmolytische Studien iiber die Wand der Vacuolen”’ (‘ Prings- hem, Jahrb.,’ vol. 16, 1885, pp. 565—6). £ Not impossibly, different zymases are concerned. See Wortmann (‘ Zeitsch. fiir Physiol. Chemi6,’ vol. 6, 1882, pp. 287—329, especially pp. 321—329). Host and Parasite in certain Diseases of Plants. 429 walls; but as soon as the protoplasm of a cell succumbs, it signifies its defeat by collapsing, and then its own more or less acid cell sap filters through to the walls and hyphe. If this view is correct, and the evidence supports it entirely, it is clear that any variations in the host-plant which lead to weakening the outposts—cuticle and cell-wall —or diminishing the fighting power of the protoplast, increase the advantages of the hypha to a correspcnding extent; and we have seen that such variations exist when circumstances cause the cells to become more watery and turgid, the cell-walls thinner and softer, and so forth. But, no doubt, the most important event is the lowering of the resisting power of the protoplasm, as must happen whenever external changes—such as low temperature, murky weather and a saturated atmosphere, &c.—combine in lessening the activity of respiration and assimilation, and consequently bring about the accu- mulation and possible filtration of organic acids, glucose, aspa- ragin, &c.; for, in the first place, the lowered metabolism means less resisting power, no matter what hypothesis we adopt ; and, secondly, the organic acids themselves prove an internal source of weakness if they become too abundant, and filter through the partially dis- organised protoplasm. The protoplasm, then, has its powers di- minished or destroyed by the accumulation and inhibitory action of products of its own activity. Fortunately, however, we have something more than the above evidence, strong as it is, to support this view. Miiller-Thurgau found, in the case of grapes devastated by Botrytis cinerea,* that the Botrytis mycelium lives on the sugar, acids, and soluble nitrogenous substances of the living cells; but he also «liscovered, by means of numerous comparative analyses, that the mycelium consumes espe- cially the organic acids, the sugars to a less extent, and the soluble nitrogenous matters were all converted into insoluble nitrogenous substances. No doubt some of the destruction of the acids is to be put down to direct oxidation, but much is due to assimilation by the | fungus. Similar events were found to occur when the Botrytis was cultivated as a saprophyte on the j Juice of grapes. It is, however, not difficult to give experimental proof of the accu- racy of the statements that the entrance of the hypha into the cell is dependent on the condition of the protoplasm. . If the mycelinm of one of these fungi is placed on an dulete * Thiel’s ‘ Landwirthsch. Jahrb.,’ 1888, pp. 83—160. + Penicillium behaved very differently : it took the sugars in greater proportion than the acids, and left the juices more acid than before. Botrytis, on the other hand, left the juices less acid than before, and more concentrated owing to the evaporation of water from the injured grapes, and it is interesting to note that these diseased (so-called edelfdule) grapes yield the best and sweetest wines of the Rhine district. 430 Prof. H. Marshall Ward. The Relations between livmg carrot, or turnip,* and the whole placed in a moist atmo- sphere, &c., the hyphe do not at first enter the tissues as above de- scribed, but form a dense mycelium on the surface, and branches from this slowly penetrate into the interior, producing the symptoms referred to. If the carrot or turnip is first submerged for half a minute into boiling water, however, the hypheze plunge into the outer cells (the protoplasm of which has been killed by the hot water) at once. These facts are easily explained when we recognise that the hot water causes plasmolysis of the cells, and escape of the sap into the intercellular spaces, cell-walls, &c.; in short, destroys the fighting power of the protoplasm against the hyphe. Moreover, the latter are invigorated by their saprophytic nutrition, and are able to excrete such quantities of ferment that the still living cells ie: in the tissues are unable to withstand the attack. Equally conclusive is the following experiment :— A mature firm shoot of a Petunia was infected with the mycelium, and the hyphe penetrated into the cortex about 1cm., and then grew no further; evidently because the cell-walls were thick, and their protoplasm disposed of the poisonous zymase as fast as it reached them. When the infection was made on slightly etiolated, rapidly growing shoots, however, the fungus entered at once, and destroyed the entire shoot off-hand.+ This is explained by the thinner, watery cell-walls, and the less vigorous protoplasm, more acid cell-sap, and so forth, of the latter offering less resistance to the zymases or poison execreted by the hyphe. Another excellent case is the following. During the very wet, cold, and dull weather of the summer of 1888, plants suffered a good deal from such diseases as we are discussing, and the white lily- buds were utterly destroyed in my neighbourhood by an epidemic of Botrytis,t aggravated by the low rate of transpiration, and conse- quently retarded respiration and metabolism, and the diminished assimilation leading to paucity of carbohydrates. The cell-walls were thin and watery, the sap unduly charged with acids, &., and the protoplasm of the cells less capable of dealing with the poison emitted in larger and larger quantities by the hyphe of the invading fungus.§ it was a very easy matter to directly infect the tissues of these lies at the time mentioned, but considerably more difficult to do so when * As a rule, roots are less acid than other organs, and inflorescences more so than leaves, which again are more acid than the stem (G. Krauss, ‘ Ueber die Wasserver- theilung in der Pflanze, IV, Die Aciditit d. Zellsaftes,’ 1885; also Warburg, loc. cit. p. 116). + De Bary, ‘ Bot. Zeitung,’ 1886, col. 440—441. t See ‘ Annals of Botany,’ vol. 2, 1888, pp. 319—376. § Warburg showed that the leaves of Lilium candidum contain more aa when the temperature is lowered (op. cit., p. 140). Host and Parasite in certain Diseases of Plants. 431 the weather improved ; and I have noticed the same fact in other cases as well. Tnvigoration of Mycelium and Conidia by Saprophytic Mode of Infe, and Differences in Behaviour of Successive Generations. We have seen from the foregoing that the relations of the host to the parasite may depend very much on the condition of the former, as induced by the complex action of the environment. I have now to show you that the variations from a normal which culminate in an epidemic are not confined to the host; but that the parasite also exhibits phenomena leading to the same result. That the mode of nutrition influences the vigour and size, &c., of a fungus is a fact well known; but it is a comparatively recent dis- covery that certain fungi, usually saprophytic in their habits, may be educated as it were to parasitism.* Thus, Penicillium glaucum, usually regarded as the type of a saprophyte, causes rotting in fruits, bulbs, &c., when its spores penetrate into a wound in the living organ;f and many other fingi usually met with as saprophytes are capable of assuming a parasitic mode of life if opportunity arises,t e.g., species of Mucor, Pythium, Nectria, Agaricus, &c. The most instructive of all is the genus Botrytis, however, for it is apparently possible to carry the process of “educating” this sapro- phyte to habits of parasitism much further than in any other cases known. lt was pointed out as early as 1874, by Zimmermann,§ that Botry- tis cimerea, long known as a common saprophyte on fallen dead vine leaves, passes from the rotting débris on the ground to the healthy living leaves of several plants and develops spots on them ; and the same fungus has been found as a parasite on the male in- florescences of junipers, thujas, and other Conifers,|| as well as else- where. But a still better case than any of these is the occurrence of a severe epidemic on the gentians in the Jura during the wet summer of 1888.4 The infection of the plants occurred in the young parts * The converse is also true to a certain extent. See B. Meyer ‘“‘ Ueber die Entwicklung einiger parasitischen Pilze bei saprophytischer Ernahrung”’ (‘ Landw. Jahrb.,’ 1888, vol. 17) ; and Brefeld, ‘Botan. Unters. i. Hefenpilze,’ Part V, 1883. + See Sorauer, ‘ Pflanzenkrankheiten,’ vol. 2, p. 92; Miiller-Thurgau (op. cit.) says Penicillium causes a speckling of living grapes. f£ See de Bary, ‘Comp. Morph. and Biol. of the Fungi,’ pp. 379—380. § “Ueber verschiedene Pflanzenkrankheiten” (‘Hamburger Garten- und Blumen- zeitung,’ 1874). || Klein, ‘Verhandl. d. Zool.-Bot. Gesellsch. zu Wien’ (vol. 20, p. 547), and Sorokin, ‘ Mykologische Skizzen’ (Charkow, 1871). {| Kissling, ‘ Zur Biologie der Botrytis cinerea’ (Dresden, 1889, p.6). It is worth notice that this epidemic occurred in the same dull, cold, damp summer (1888) as the one on lilies in this country. 432 Prof. H. Marshall Ward. The Relations between of the flowers, especially the stigmas and anthers, by means of spores. After growing outside the organs for some time, the hyphe—now invigorated by their saprophytic nutrition—were able to enter other tissues, e.g., those of the leaves, pedicels, &c. Experiments were then tried with Hcheveria metallica* with complete success, and it may be remarked that this disease is very common in a sporadic form on Crassulace in green-houses. Infections of Liliwm were also successful, and Hemerocallis flava was destroyed with extraordinary rapidity. Many other plants were also infected successfully. Tn all these cases the spores only infected (directly) the most Fokiexte or least protected parts of the flower, but the resulting mycelium when invigorated by its growth in the dead tissues was capable of directly infecting, the ordinary tissues of plants. ‘It will be remembered that de Bary came toa similar result with his experiments,f and I have observed the same phenomenon over and. over again with several of these forms. There is one, for in- stance, which sometimes cases great havoc among snowdvrops in the early spring, and I found that the infection occurred especially by means of small invigorated mycelia developed from spores which ger- minated on the dead tissue of the sheaths at the base of the leaves; these hyphe easily penetrated into the etiolated bases of the leaves and young flower-buds, especially when the plants were partially buried in snow.t Similarly with omtions, hyacinths, and other plants; and similarly in every greenhouse on plants too far from the light, - and often in store cellars on etiolated geraniums, calceolarias, and other plants put by for the winter. _ But a still more remarkable proof of the influence of nutrition on the fungus is shown in the recent discovery that the conidia of suc- cessive generations of the Botrytis have different powers of infection. .It has already. been pointed out that the conidia may or may not directly infect the tissues, and that one set of events affecting this is the condition of the tissues themselves : another, however, is the kind of food-materials on which the mycelium is growing which yields the conidia. I have found that if the attempt is made io infect a carrot with conidia, taken directly from the Botrytis growing on artificial solutions it often fails, whereas the conidia produced on the carrot as a substratum succeed more easily; moreover, there was so much variability in the infections, and especially in the rate of progress of * N.B.—This is one of the plants which is particularly rich in organic acids, and shows well the influence of warmth and daylight in at them (see Warburg, loc. cit., especially pp. 125, 182, 183, 134). + ‘Bot. Zeitg.,’ 1886, col. 396 (see also the remark under Sclerotinia Fuckeliana in ‘Comp. Morph. and Biol. of Fungi,’ p. 380). { A circumstance distinctly calculated to retard the decomposition of the = and to bring about a tender etiolated condition. Host and Parasite in certain Diseases of Plants. 433 Fre. 11. A young snowdrop plant, artificially infected with Botrytis. The infection- spot (@) is sunken in the centre, and deep sienna brown or nearly black; the _+ paler area around. is yellowish-brown. The fungus hyphe extend from this centre into the tissues, or not, according to circumstances. (See text.) the infecting mycelium, that I was continually puzzled to account for the phenomena, and suspected that the conidia varied in infecting power, according to their size as well as the manner of culture. This would be a natural conclusion from what was already proved with regard to the invigoration of the mycelium, for, after all, conidia are only slightly specialised bits of mycelium cut off for purposes of rapid propagation,* and we. may expect them to be directly affected by * See Sachs, ‘Lectures on Phys. of Plants,’ p. 722; also de Bary’s critical remarks in ‘Comp. Morph. and Biol. of Fungi,’ p. 129. . 434 Prof. H. Marshall Ward. The Relations between Vie. 12. Spores of Botrytis germinating on the epidermis of a snowdrop, and infecting it by means of their germinal tubes, the tips of which penetrate the cell-walls by means of secreted zymases, and cause them to turn brown at the points of entrance, as shown by the shading. (Highly magnified.) everything which promotes or retards the vigour of the mycelium. | regard the conidium as distinct from any vegetative piece of mycelium chiefly in its capacity to form the necessary (cellulose-dissolving, &c.) ferment or zymase* in greater quantity or in a shorter time (with respect to the size of the organ), and look upon its size, shape, and colour, &c., as so many adaptations to the mode of life of the fungus. Be this as it may, the conidia vary in infective power according to their nutrition—z.e., according to the substratum on which the — mycelium grows—and according to the generation to which the coni- dium belongs, 1.e. (as I interpret it), according to the increasing vigour of the successive mycelia which produce the conidia.t This latter fact is best demonstrated as follows: A crop of conidia is grown on a given pabulum, e.g., on the moist sclerotium ; the conidia are sown on the cut surface of ripe, sweet pears, and produce mycelia, * See ‘Annals of Botany,’ vol. 2, 1888, p. 356. + Kissling (op. cit., p. 31) has proved this for Botrytis cinerea. Host and Parasite in certain Diseases of Plants. 435 whence conidia again arise ; these are again sown on pears, and produce a still more vigorous mycelium and crop of conidia, and so on. Calling the first crop of conidia generation I, and the second crop generation II, the third generation III, and so on, it was found that if the conidia of generation I are sown on similar leaves of a Sempervivum in a tiny drop of sap they do not infect the leaf; whereas those of generation II, similarly sown, infect the leaf at once, and those of generation II] are still more virulent. Kissling,* who has paid special attention to this point, and has carried the matter much further than other observers, measures the infective power of the conidia by the size of the teeta. i they produce in a given time. As I have shown, the penetrating germinal hypla causes the cells in its neighbourhood to collapse and turn brown, because the excreted ferment or poison destroys the cellulose, and makes the protoplasm unable to retain the sap, which consequently suffuses and browns the area concerned. Now it is obvious that the rapidity with which this browning occurs may be taken as a rough measure of the progress —and, Paerators, of the destroying power—of the infecting hyphe, other things being equal. Well, Kissling took the necessary precau- tions, and set the conidia of succeeding generations I, II, and III to work on the surface of various fruits and other parts of plants, of course using the same substratum in any one series of experiments. | | | -----| gen.|I -~—| gen. Rig gen. | Fig. 13. Diagram constructed to show the relative progress of infections produced by successive generations of conidia of Botrytis cinerea (see text). The three different generations are denoted by differences in the characters of the curves. The horizontal base line is divided into six equal parts representing days; the distances measured on the ordinates represent the diameters of the disease-spots in millimetres, according to Kissling’s experiments. * Loc. cit., pp. 22—29. : ee a ee —— 7 —— ——— se — ———---- -- Ese = ——— )) ese, He ) 436 Prof. H. Marshall Ward. The Relations between In a day or two the infected circular areas, as marked by the brown colour, were large enough to measure in millimetres, and by measure- ments on successive days he was able to judge of the progress of this extraordinary race, and he comes to the conclusion that on the same substratum the conidia vary, according to their generation, in their power of destroying the tissues. Those of the third generation, for instance, not only germinate more rapidly and vigorously—indications that they start in the race better equipped in the matter of food- materials and ferment-yielding substances—but they also destroy the cells of the host which they compete with more rapidly—which, no doubt, indicates thati they are able to produce or manufacture more poison in the same time. Summary of the Factors of an Epidemic—Bearing of the Discussion on other Parasiiic Diseases—Conclusion. It will be clear from the foregoing that in the case of an epidemic fungus disease, such as we have been considering, there are several — classes of factors to be regarded, and I may sum up the chief points somewhat as follows. First, we have the normal healthy host-plant, with all its hereditary (internal) and adaptive peculiarities ; secondly, we have the parasitic fungus, also with its disposition. Then we find, thirdly, that, apart from its inherent powers of variation, the host is subject to variable external influences during its life, which may produce such changes in the cell-walls and contents, &c., that the plant approaches nearer and nearer the limits of health, wide as we may regard these. On the other hand, we have, as a fourth considera- tion, the parasite also varying under the influence of changes in the factors of the environment, and its variations may, of course, be also dangerous to its welfare; but they may, on the contrary, be in such directions that it is enabled to profit by the counter-variations of the host. When the combined effects of the physical environment are unfavourable to the host, but not so or are even favourable to the parasite, we find the disease assuming a more or less pronounced epidemic character. It is not pretended that we have here a totally new idea, because it has long been known that some organisms which bring about parasitic diseases do vary in the intensity of their effects, and can be made to do so artificially, and we know that some of the most brilliant results in biology have been obtained in connexion with certain lower organisms ; but I have simply sought to show some of the links in the chain of causes and effects in the definite case of certain epidemic diseases of plants produced by the parasitism of some of the more highly developed fungi, and this, I think, has not been done before. If the preceding argument is admissible, new light will be thrown 4.7 Host and Parasite in certain Diseases of Plants. 437 not only on the cases of parasitism referred to, but also on the behaviour of the host in its struggle for existence with the factors of the inorganic environment, generally. The question as to how far this view of the matter may be extended to other parasitic diseases of plants cannot be answered at present. Obviously the reflections excited will suggest lines of enquiry, and I may appropriately bring these remarks aoe a conclusion by a few brief comments on what is known as to the behaviour of other classes of parasitic fungi in this connexion. Omitting the Schizomycetes, partly because they have a literature to themselves, and partly because they rarely* occur as parasites in the cells of plants, possibly owing to the acidity of the sap; and the Myxomycetes, of which Woronin’s Plasmodiophorat is the best and most curious case; we have pronounced parasites (capable of produc- ing epidemics) among the Peronosporee, one of which (Phytophthora infestans) has been more studied, probably, than any other true fungus parasite, at any rate so far as its life-history is concerned. Much that has been stated in this lecture would, apparently, apply to the potato disease, and in view of the extreme interest that neces- sarily attaches to that malady, I draw attention to the following points of interest. Suppose we take a potato plant the leaves of which are very slightly marked with minute disease spots, and divide it into two halves as exactly alike as possible, and place each half in a tumbler of water; the two tumblers, with their half-plants, are then placed in an ordinary room, side by side, at a temperature of about 20° C., and one is covered close with a bell-jar and the other left uncovered. In a short time—often a few hours—the covered leaves become black and rotten with-the disease, whereas the uncovered one will go on looking fresh for several days, though it also succumbs at once if covered.§ The question arises whether the rapid spread of the fungus and the rot it causes here are simply owing to the increased supply of water, as the tissues become turgid in the saturated atmosphere under the bell-jar ; or whether we have not here again, in addition, a case where the diminished access of oxygen to the interior of the tissues of the host results in an accumulation of organic acids and other substances which make the excessively turgid cells and thin, watery cell-walls more than usually easy prey to the parasite. * Exceptions probably occur in the case of Wakker’s hyacinth rot, the American “ pear-blight,” the ‘‘ peach yellows,” and a few others. See de Bary’s ‘ Lectures on Bacteria,’ 1887, p. 177, and the ‘Reports of the U.S. Department of Agricul- ture,’ especially No. 9, 1888. + Pringsheim’s ‘ Jahrb. f. wiss. Bot.’ (1878, vol. 11, p. 548). ~ See de Bary ‘ Morph. and Biology of the Fungi’ for the chief literature. § See de Bary ‘ Die gegenwirtig herrschende Kartoffelkrankheit,’ 1861, p. 55. 438 Prof. H. Marshall Ward. The Relations between I ought to add, that if a potato plant is grown in a pot and kept under a bell-jar (untouched by Phytophthora) normally lighted, in the summer, the excessively watery dark-green shoots often develop hump-like outgrowths, composed of very large, thin-walled cells, which may be regarded as due to the excessive turgescence and hypertrophy of these cells. Presumably they contain relatively large quantities of organic acids, &c., and everything indicates that such a shoot would easily succumb to the Phytophthora, as in fact it does. Kihn long ago noticed* that there are two periods when the potato shoot is most easily infected by the Phytophthora. The first is while still young—fully developed internodes are much more difficult to infect than young growing ones, a fact well known and easy to con- firm; the second period is said by Kihn to occur after the tissues are far advanced, at the end of July or the beginning of August, and this would seem to be borne out by the experience of cultivators generally. I am inclined to regard this second period as coincident with the time when the plant is particularly rich in the products of assimilation on their way down to the tubers. They travel chiefly as glucose, and one consequence of the abundance of this carbohydrate, and the increased metabolism it supports, is an increase in the organic acids. If wet and dull weather sets in when the tissues are thus, so to speak, overflowing with such substances, the Phytophthora is peculiarly favoured, and can spread through the plant with the rapidity characteristic of an epidemic. In the alliea genus Pythium, the phenomena are so similar that we may assume that the fungus behaves like Peronospora: the species are often saprophytes, however. The question now arises, can these ideas be extended to the case of other parasitic fungi? It would be difficult to say with regard to the Saprolegnriee and the Mucorini, because so little is known of their parasitism. As regards the Ascomycetes generally, we may expect great differences in respect to types like the Gymnoascee, Rhytisma, Hysterium, the Hrysiphee and the Spherias, and they certainly occur. Some Nectrias at any rate (fe.g., N. cucurbitula, N. cinnabarina, and N. ditissima) behave so differently towards the host that we may probably conclude that the mode of procedure is unaffected by such variations on the part of the latter as have been sketched; and the same may be said of the wood-destroying Hymenomycetes (e.g., Agari- cus melleus, Trametes radiciperda, Polyporus sulphureus, &c.). In all these cases the tree, as a whole, suffers in an indirect manner: these various cankers and rots, &c., destroy, for the most * ‘Ber. aus dem Physiol. Lab. u.d. Versuchsanstalt des Landw. Instituts d. Univ. Halle,’ 1872, pp. 81—82, quoted by Sorauer, vol. 1, p. 140. + ‘Unters. a. d. Forstbot. Inst. zu Miinchen,’ vol. 1, pp. 88 and 109, and vol. 3 also R. Gothe (Thiel’s ‘ Landw. Jahrb.,’ 1880, vol. 9, p. 837). | ees oad aD Me | y Host and Parasite in certain Diseases of Plants. 439 L2,.72002%¢. \ 12°30 720072 « 3:50. P72» Fie. 14. Zoospores of a species of Pythium allowed to germinate in water on a piece of a longitudinal section of a bean-stem. ‘The zoospores (a) soon come to rest, and one was noticed at mid-day on an exposed cell (0), lying nearly over its nucleus. At 12.30 this spore had begun to germinate and enter the cell (ce). At 2.5 p.m. the germinal hypha had turned to the left, and com- menced to bore through the side-wall with its tip (d), At e is shown the progress by 5.30 p.m. on the same day; and at f (smaller scale) the condition of affairs at 12.30 next day. That thesejhyphe pierce the walls by means of secreted. zymases can scarcely be doubted after what has been proved for Botrytis. 440 Prof. H. Mavshall Ward 1 he Ieelavona eae part, structures which are already dead, and so interfere with the transpiration current, and other large groups of functions, more by the mechanical injury done than by direct injury to living cells.* In the group of the Ustilaginece we have some of the most remark- able parasites known, and the relation of the host-plants (chiefly species of Graminez and Cyperacez) to them must be ven different in detail. Fie. 15. Zea mais. Portion of inflorescence (reduced) with malformations: pro- duced by the parasitism of the fungus Ustilago Maidis (Sorauer). In the more typical cases we find that the sporidia or conidia ger- minate in artificial nutritive media, and go on producing generation after generation of their like,f and this undoubtedly occurs in the open fields, &c. Brefeld states that he has cultivated one form through more than a hundred successive cultures in the course of a whole year, and that this corresponds to about 1500 successive sprout- series or generations,t but towards the end of the period the germi- nating power of the successive conidia became weaker and weaker, and at last failed. * The germinal hyphe developed from the spores of such fungi often find their way into the wood, cambium, &c., by means of wounds, caused by mechanical breakage, the nibbling of mice, squirrels, the punctures of insects, frost-cracks, the blows of hailstones, and so forth, which introduce us to a different aspect of the relations between host and parasite. + Brefeld, ‘Bot. Unters. tither Hefenpilze,’ part 5, Leipzig, 1883. + Brefeld, in a lecture before the Klub der Landwirthe zu Berlin, 1888 OC Nach- een aus d. Klub d. Landw. zu Berlin,’ 1888, Nos. 220—222). Host and Parasite in certain Diseases of Plants. 44] He also found that the conidia germinate, by developing a germinal tube only at a given period, and not at any indefinite time they may happen to be sown: consequently they are unable to infect the host unless they happen to be on the proper spot at the right time. Now Kihn showed long ago* that the infection of the cereal by Ustilago can only occur near the “collar” of the young germinating seedling, and although differences have arisen as to the exact spot in this region which alone can be infected, there is one point on which all are agreed, namely, that the germinal tube can only enter the young actively growing tissues in that region. Immediately the first internode is completed, the seedling is proof chew infection in the open.f That it is really a matter of the age and condition of the tissue is beautifully demonstrated by Brefeld, who showed that if the conidia are forced into the bud by means of a syringe, so that they can germinate in contact with the embryonic cells at the growing point, infection may be ensured at any time. But far the most interesting point about these fungi is that when the germinal hypha is once inside the tissues it goes on growing with them, keeping between the cells. Although we have almost no infor- . mation as to details here, it can hardly be doubted that the chief agent in maintaining the balance of position in this case is the living substance in the cells of the host; but I know of no explanation for this beyond the general one, that so long as the cells of the internodes are actively performing their normal functions, the hyphe have to be contented, so to speak, with a sort of suppressed existence in the intercellular spaces and middle lamella of the walls. True, when the young fruits begin to fill out, the mycelium accom. plishes a sharp revenge by destroying the whole fruit; but it is obvious that the relations which determine the epidemic or sporadic character of the disease are those between the tissues and the germinal hyphe and young mycelium, and there are great variations in these matters, even in the group of the Ustilaginece itself. § Very different again must be the relations in detail between host and parasite in the case of those Uredinece which cause epidemic leaf diseases, especially those which form haustoria,|| and it is almost impossible * © Krankh. d. Kulturpflanzen,’ 1859, p. 46. _ + Cf. Wolff, ‘Brand des Getreides,’ Halle, 1874; Hoffmann, ‘ Bot. Unters,’ 1866; “Ueber den Flugbrand,’ p. 206; Kiihn, “ Beobachtungen w. d. Steinbrand d. Weizens”’ (‘Oesterr. Landw. Wochenschr.,’ 1880). t This no doubt explains the fact that ina wet spring nearly all seeds with spores _ attached become infected, because the tissues remain in a youthful condition longer than in a dry season. § E.g., contrast the behaviour of Protomyces, Entyloma, and Ustilago Maidis, for instance, with that of most other Ustilaginee. || In all cases where haustoria are developed the mycelium enters into a peculiar VOL, XLVII. 2K 449 Prof. H. Marshall Ward. The Relations between to say anything about their nutrition beyond the general statement that they must have established such close temporary relations with the living cells of the host that their protoplasm and that of the host can go on absorbing nutriment from the same sources. This would seem to be proved. by the curious phenomena of hypertrophy which they induce, e.g., the young shoots of Huphorbia cyparissias are entirely altered in habit by the Acidium of Uromyces Pist, and the well-known “‘ witches’ brooms ”’ of the silver fir,* for although the changes induced Fic. 16. A specimen of “ witches’ broom,” on the silver fir, caused by the stimu- lating action of the Uredinous fungus Acidium elatinum, the mycelium of which lives perennially in the cortex, &c., of the fir, and causes some of its buds to grow up into erect shoots of totally different habit from the normal branches. The blister-like Aucidia are visible on the leaves at a and b (Hartig). imply that the cells are carrying out their functions in a modified manner, still they grow, divide, and evidently discharge their main duties much as usual. Consequently it is impossible to believe that any individual cell suffers much direct injury, and at least the proto- plasm and nucleus, and even the chlorophyll corpuscles, &c., may re- symbiotic connexion with the cells, and for some time merely taxes them, as it were, rather than injures them directly. Of course, there is ultimate injury, and even death, brought about in these cases; but how much this differs in different cases is evident from comparison of other fungi, like Peronospora parasitica, Podosphera Castagnei, with Uredines such as Hemileia vastatrix, Melampsora Goepper- tiana, &e, * Such hypertrophies are not confined to the Uredinex, however: ef., de Bary, ‘Morph. and Biol. of Fungi,’ 368—369, and Zopf (Schenk, ‘ Handb.,’ vol. 4, 1889 pp. 504—507). Host and Parasite in certain Diseases of Plants. 443 main intact for weeks or months. No doubt in these cases also the entrance of the hyphe or haustoria into the tissues is aided by any factors which cause the cell-walls to be softer or thinner than in the normal condition ; and it is certain that many failures by those who have experimented with Uredinous fungi are attributable to their sowing the spores on older, well matured tissues. We are here, however, abandoning the subject of the present lecture, because, in the first place, the phenomena just referred to appertain to sporadic rather than epidemic diseases, and because, secondly, they tend to the subject of symbiosis proper, where the rela- tions between the host and the parasite have become so arranged that both may be said to benefit by the commensalism, as exemplified in the lichens, and some of the recently described cases of mutualism between fungi and the roots of Phanerogams. April 17, 1890. 3 Sir G. GABRIEL STOKES, Bart., President, in the Chair. The Presents: received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “Preliminary Note on Supplementary Magnetic Surveys of Special Districts in the British Isles.” . By A. W. Rtoxzr, MeAee ho, and TH, Thorpe, Ph.D., B.Sc. (Viet.), PRS: Received March 5, 1890. During the summer of 1889 we carried out additional magnetic surveys of the Western Isles and the West Coast of Scotland, and of a tract of country in Yorkshire and Lincolnshive. Both districts were selected with special objects in view. We had found that powerful horizontal disturbing forces acted westwards from the Sound of Islay, from Iona, and from Tiree, and we had deduced a similar direction for the disturbing force at Glenmorven from Mr. Welsh’s survey of Scotland in 1857-58. The whole district presents peculiar difficulties, partly from the fact that local disturb- ance is likely to mask the effects of the regional forces, partly because the normal values of the elements must be especially uncertain at stations on the edge of the area of our survey. If, then, the general westward tendency of the horizontal disturb- VOL. XLYII. 2° 444 Magnetic Surveys in the British Isles. | [Apr. 17, ing forces was due to some source of error, stations in the extreme- south of the Hebrides would in all probability be similarly affected. If the directions of the forces were due to a physical cause, such as a centre of attraction out at sea to the west of Tiree, then the disturb- ing forces in the Southern Hebrides would almost certainly be directed southwards towards it. The observations made last summer prove (1) that the direction of the disturbing horizontal force at Bernera, which is the southernmost island of the Hebridean group, is due south; and (2) that, as this point is approached from the north, the downward vertical disturbing attraction on the north pole of the needle regularly increases, which exactly agrees with the supposition that a centre of attraction is being approached. There is, therefore, now no doubt that there is a centre of attraction on the north pole of the needle to the south of the Hebrides and to the west of Tiree. (3) In one of the maps communicated to the Society last year we drew two lines, bounding a district about 150 miles long and 40 miles broad, in Yorkshire and Lincolnshire, and gave reasons for the belief that a ridge line or locus of attraction lay between them. This conclusion has now been tested by means of thirty-five addi- tional stations, with the following results :—(1) At aJl stations (with one exception) on or near the two lines, the horizontal disturbing forces tend towards the centre of the district they bound. (2) The downward vertical disturbing forces are greater in the centre of the district than at its boundaries. In particular, there are two well-marked regions of very high vertical force. (3) The greatest vertical force disturbances occur at Market. Weighton, where the older sedimentary rocks are known to approach the surface, and at Harrogate, which is on the apex of an anticlinal. (4) The central ridge line runs from the Wash parallel to the line of the Wolds to Brigg. Thence it appears to turn west, and reaches Market Weighton vid Butterwick and Howden. One or two addi- tional stations are, however, required to determine whether this bend is real, or whether the line runs direct from Brigg to Market Weighton. From the latter town it passes to the limestone district of Yorkshire and traverses its centre. It has not yet been traced west of the Jine of the Midland Railway between Settle and Hawes, but there is ground for believing that it continues to the Lake District. Although, therefore, one or two points of detail remain for further investigation, the existence of a line of attraction 150 miles long is proved beyond the possibility of doubt, and for about 90 miles its. position is known +o within 5 miles. There are, then, even in those parts of England where the super- | i lala 1890.] Variations oceurring in certain Decapod Crustacea. 445 ficial strata are not magnetic, regions of high vertical force comparable in size with small counties, and ridge lines or loci of attraction as long and almost as clearly defined as the rivers. Their course is closely connected with the geology of the districts through which they run. Il. “The Variations occurring in certain Decapod Crustacea.— I. Crangon vulgaris.” By W. F. R. WEtpDon, M.A., Fellow of St. John’s College, Cambridge, and Lecturer on Inverte- brate Morphology in the University. Communicated by Professor M. Foster, Sec. R.S. Received March 20, 1890. Tt is well known that two sets of animals, belonging to the same species, but living in different places, exhibit differences from one another by which they can, in many cases, be easily distinguished. But it is at the same time equally certain that the forces determin- ing the differences between local races of the same species do not so act as to produce the same effect upon all individuals of the same race: for I am aware of no case in which the individuals composing any race of animals—however small and isolated the area in which they live, however uniform the conditions which obtain throughout that area—have been shown to resemble one another exactly in any character. Since the adjustment of a local race to the average proper to it is not complete, the question arises, whether it is not possible to deter- mine the degree of accuracy with which this adjustment is effected, and the law which governs the occurrence of deviations from the average. The object of this paper is to give an account of certain observations made at the laboratory of the Marine Biological Associa- tion at Plymouth, in order to determine, first, the average length of three or four organs which admitted of accurate measurement, and, secondly, the frequency with which the average length and every deviation from it occurred in one or two local races of Crangon vulgaris. In making this investigation, I have had the great privilege of being constantly advised and helped, in every possible way, by Mr. Galton. My ignorance of statistical methods was so great that, without Mr. Galton’s constant help, given by letter at the expenditure of avery great amount of time and trouble, this paper would never have been written. Iam glad to take this opportunity of expressing my gratitude for his generous conduct. I have also to thank Dr. Donald MacAlister for explaining to me many points connected’ with the law of error, and for helping me in various ways. 2h 2 SSS Se eee eS SS SSS 446 Mr. W.F.R. Weldon. The Variations [Apr. 17, Mr. Galton has, as is-well known, studied the frequency with which deviations from the average size of certain organs occur in man, in certain plants, and in moths. The result of his investigations has been to show that deviations from the average size of the organs measured by him occur in every case with the frequency indicated by the law of error. These results were, however, based on an investi- gation either of civilised man, or of a domesticated animal or plant: and Mr. Galton has himself pointed ont that in the majority of cases studied, the effect of naturai selection is probably insignificant. The similar investigations of Quetelet and others are also confined to civilised man. It has, therefore, seemed worth while to attempt an investigation of the variations in the size of certain organs which occur in a species living in a wild state, upon which natural selection and the other destructive or plastic influences from which domestic animals and civilised man are alike protected may be supposed to act with full effect. In his recent work on heredity,* Mr. Galton predicted that selec- tion would not have the effect of altering the law which expresses the frequency of occurrence of deviations from the average: so that he expected the frequency, with which deviations from the average size of an organ occurred, to obey the law of error in all cases, whether the animals observed were under the action of natural selec- tion or not. ‘The results of the observations here described are such as to fully justify Mr. Galton’s prediction. These observations relate entirely to the lengths of organs, or parts of organs. ‘The measurements of these lengths were made either with a pair of compasses, in the case of the greater lengths, or in the case of smaller parts by means of a microscope, provided with cross-wires, and travelling on a screw of known pitch. The results are, I believe, accurate to within about 0°-l mm. The edges of the parts measured were in many cases so uneven, and the effect of the spirit in which the specimens were. preserved was probably so con- siderable, that a greater degree of apparent accuracy in the measure- ments would not have implied a more reliable result. In order to compare the organs of one individual with the corre- sponding parts of another individual of different size, it was evi- dently necessary to express the dimensions of each organ in terms of the length of the body of the individual to which it belonged. All the measurements used in this paper are therefore, expressed in terms of the total length of the body, which is taken as 1000. Having obtained measures of the length of an organ in a suffi- ciently large sample of individuals, the frequency with which the various magnitudes occur may be conveniently exhibited in the fol- * ‘Natural Inheritance,’ pp. 119—124. 1890. ] occurring in certain Decapod Crustacea. 447 lowing way, which is that adopted by Mr. Galton:—The values ob- tained are sorted and arranged in order of magnitude; then, at equal distances along a given base, ordinates are erected equal in number to the observations, one ordinate being proportional to each observed value of the organ. By joining the tops of these ordinates, a curve is obtained such as that drawn in fig. 2. If the base-line of such a curve be divided into one hundred parts, then the proportion of individuals measured, which possess the organ from which the curve is constructed, of a size greater or less than any given magnitude, can be readily ascertained. For example, in fig. 2, which shows the distribution of lengths of the carapace in 400 female shrimps from Plymouth, the ordinate, whose length is 256, stands at grade 20°, showing that 20 per cent. of the indi- viduals examined had the carapace longer than 256 (the body length being 1900), while in the remaining 80 per cent. the carapace was shorter than this. A curve constructed in the manner directed is nearly always sym- metrical about its middle point: and this point therefore closely approximates to the average of the whole number of observations from which the curve was constructed. The value of the middle ordinate will always be taken, in what follows, as the average value : it will, in accordance with Mr. Galton’s notation, he spoken of as the Median, and denoted by the symbol M. Lach curve, therefore, gives by simple inspection the average value of the organ to which it refers. In estimating the deviations from the average which occur in each case, the magnitude of the average itself is evidently of no im- portance: and the ordinates of the curve may therefore be considered with reference to an axis passing through the point M, so that the ordinate of M becomes zero. When measured from this axis, half the ordinates of the curve are of course positive, the other half being negative. If the frequency, with which the observed deviations from the average occur, obeys the law of error, then the curve just described should be a “ curve of error,” whose ‘‘ probable error ”’ is represented by the ordinates at the 25th and 75th grades. These grades are the boundaries of the first and third quarters of the base: they will, ‘therefore, be spoken of (again in accordance with Mr. Galton’s nota- tion) as Quartiles,; and will be denoted by the symbols Q, and Q, respec- tively. Ina perfectly normal curve, Q, and Q, are of course equal in magnitude and opposite in sign. In the observed curves there was generally a slight difference between the two: and the mean value of the two is therefore adopted as the “ probable error,” which will be denoted by the symbol Q. _ In order to determine the correspondence between the observed 4148 Mr. W.F.R. Weldon. he Variations [Apr. 17, curve and the curve of error, the ordinates of the observed curve will be compared with those of the curve of error at certain fixed erades. This may be most conveniently done by considering the ordinates of the curve of error at those grades as multiples of the “‘ probable error ’”’ of the curve. The grades chosen, together with the ordinates of a curve of error, expressed in terms of its probable error, at those grades, are as follows :— Table I.—Ordinates of a Curve of Error, in Terms of Q. Grade. Ordinate = Q x Grade. Ordinate = Q x 5° + 2°44 60° —0°38 10 +1°90 70 —0°78 20 +1°25 75 —1-:00 25 +1:°00 80 —1°25 30 +0°78 90 —1°90 40 +0°38 . 95 —2°44 50 0:00 It will be seen that, in order to compare a curve constructed from a number of observations with a curve of error, the following process is performed: the ordinates at the selected grades are determined, and the observed value of M is subtracted from each of these. The remainders, divided by +(Q,—Qs), should give the coefficients of Q which appear in the above table. Such a comparison will now be made petween the curve of error and the curves obtained from the measurements. _ The organs measured are four: the total length of the carapace ; the distance from the posterior margin of the carapace to the front of the median spine; the length of the sixth abdominal tergum; and the length of the telson. The parts are shown in the accompanying woodcut. Fra. 1. 1890. ] occurring in certain Decapod Crustacea. 449 In measuring the length of the sixth tergum and of the telson, these organs were removed from the body; so that the small. portion of each which projects inwards into a fold of skin, and serves as an attachment for muscles, is included in the total length. The individuals measured were all adult females; they were col- lected from widely separate places. The first sample measured consisted of 400 individuals from Plymouth Sound; a second sample, containing 300 females, was obtained from Southport by Mr. W. Garstang; and a third sample, of which 300 were measured, was sent to me from Sheerness by Mr. W. H. Shrubsole. Total Length of the Carapace.—The curve obtained by treating the total length of the carapace of the Plymouth specimens in the way described is shown in the woodcut, Fig. 2. , Fi4. 2. 20°. 26 3O° 40° Tt will be seen that the median ordinate has a length of 250°52, which is therefore the value of M. The ordinate at 25° is 255°07 = M+455; that at 75° is 246:00 = M—452; so that the mean value = $(4°554 4°52) = 4°53. 450 Mr. W. F. R. Weldon. The Variations [Apr. 17, The following table will show the relation between this curve and the normal curve of error :— Table II.—Curve of Distribution of Carapace Lengths—Plymouth. Grade. Ordinate. Ord.—M. ee Normal curve. | 5° 261 °50 +10-98 + 2°42 + 2°44, 10 258 *95 + 8°43 +186 +1°90 20 256 °05 + 5°53 +1°22 +1°25 25 255 07 + 4°55 +1-00 +1-00 30 254 °10 + 3°58 +0°79 +0°78 40 252 27 + 1°75 +0°39 +0°38 50 250 *52 0:00 0:00 0-00 60 249 -09 — 1°43 —0°32 —0°38 70 247 °29 — 3°23 —0°71 —0°78 75 246 -00 — 4°52 —1-00 1:00 80 244:°'74 — 5°78 —1°28 —1°25 90 241 °39 — 9°13 —2°10 —1-90 95 238 60 —11 -92 —2°63 —2 44 Tt will be seen therefore that the average length of the carapace in the Plymouth specimens was 250°52-thousandths of the body length, and that the frequency with which this length and the various observed deviations from it occurred was almost exactly that: indicated by a curve of error whose prob. error = 4°53. In the above table, all the steps in the determination of the co- ‘efficients:of Q are indicated. To indicate all the steps in this deter- ‘mination in the case of each race would involve a great deal of vain repetition; and, therefore, in the following table the coefficients themselves are alone indicated. It will be understood that the entry opposite each grade in this table is found by subtracting the value of M from the observed ordinate at that grade, and dividing the remainder by $(Q,—Q3). The value thus obtained should be the coefficient of Q in the table of ordinates: of a normal curve given on page 448. These coefficients are repeated in the last column of the following table. 1890. ] occurring in certain Decapod Crustacea. 451 Table III. —Ordinates of the Curves of Deviation of Carapace Lengths, each in Terms of its own Q. Bagh anaes = observed ordinate—M Q Plymouth. Southport. Sheerness. ce Grade 400 Ricearbns, 300 Sache 300 specimens. ho a 5° +2°42 + 2°86 +3°34 + 2°44, 10 +1°86 +2°11 + 2°29 re 20 +1°22 +1°29 +1°35 +1°25 25 +1:00 +0°97 +1°02 +1:00 30 +0°79 +0°70 +0°76 +078 40 +0°39 + 0°34 + 0°35 +0°38 50 0°00 0:00 0-00 0-00 60 —0°32 —0°37 —0°35 —0°38 70 —0°71 —0°80 —0°74 —0-78 75 —1:00 —1°03 =D oes —1°00 80 —1°28 —1°27 —1°28 —1°25 90 —2°10 —2°05 —1°97 —1°90 95 -—2°63 —2°68 —2°41 —2°44 The table shows that in all the races the coefficients of Q agree fairly well with those indicated by the normal curve. When these coefficients and the values of M and Q in each case are known, it is. evident therefore that the whole curve is known. The values of M and Q are as follows :— I VMIOMUR 2.5. 3 2 5 ss M = 250:05; Q = 4°53 SOUEMport 2.2... 2% Mi 246°50: Q = 3°17 - PCCRRESS ......2-5% Me 24751 7 QO = 305 It thus appears that not only does the average size of the carapace: differ in different local varieties, but the range of deviation from that average differs also. Nevertheless, the frequency with which the observed deviations from the average occur is in all the three observed cases expressed by a curve of error. Since the variations observed in adult individuals depend not only on the variability of the individuals themselves (which is possibly nearly alike in all races), but also upon the selective action of the surrounding conditions—an action which must vary in intensity in different places—the result here obtained is precisely that which might be anticipated, and it is precisely that predicted by Mr. Galton. : The same features are presented by the curves derived from the remaining sets of measurements. The following tables give the data. for constructing curves of deviation of each organ. OE eee ee ee ee SSS OES Oe eee Se eee ~ pa [ Apr. The Variations Mr. W. F. R. Weldon. A52 ‘aA [@ULLO NT ‘SUOTAIOOS SSIULOOYY OY} UI POUTUMLOJOp JOU O10 OST} OY} JO puB TA WNF104 Jo syISUoT ONT, ~ SP. o—- 66. 6— 88: IT — 68-T— Si i= &6: T— 16: 0- 60. [— 64.0- 08-0- LE. 0- ce. 0— 00: O 00-0 TP. 0+ ge. Ort g8.0+ 64-0+ 80. T + 46.0+ 46-1+ 66. [+ LG-6 + 8Z-Tt G6.36+ OP. 6+ ‘34-8 =0 | ‘96.6 =0 ‘Ch. S6IT=W | FP. o6T=W ‘qaodyynog “ynourATg ye WOSTO} YQsuaTT 88-0+ 1-1 + 18.T+ Ge. 3+ 20-§ =0 GL. TPL=W “qrodyqnog 8&.o— bear = Cea = Os = B20 c€.0- 00-0 T&.O+ 99.0+ G6.0+ v6..+ vO.G+ 09.6 + 7-8 =O ‘OV. SFT = “qynoud, gy x TA wns10y WQ0U07 SIL END 8P-o— 88: 1.— sit 16: 0—- e2-0— | L&-0—- 00: 0 Tv-O+ G8.0+ 80. T+ Le. T+ 16-6 + G6-6+ 08-% =0 "89-6241 =W ‘ssouLool.g 0&-6— 08: IT- (8) Se 60- T— 64-0— L8-0- 00: 0 66-0+ 94-0 + L6-0+ 9L-—+ 10.6 + 91-6 + —— MOE SFM) ‘0S: 6LT*=W ‘q10dqynog 89. — ‘82-8 =O ‘60: 841 = ° ‘ygnourd, g ‘sovderevo Jo uorod snourds-ys0g SS . c6 06 08 cL OL O09 0g OV ‘oper - 1890.] occurring in certain Decapod Crustacea. 453 That the deviations from the normal value of the coefficients of Q shown in the foregoing are accidents due to the small number of observations upon which the curves are based is shown by the fol- lowing table, in which each entry is the mean of the corresponding entries of all the preceding tables :— | Mean of Mean of observed observed | Grade. Bee oie Normal. Grade. aoctie te Normal. . of Q. of Q. 4 5? +2 °55 +2°44 60° —0°36 —0°38 10 +1-°99 +1:°90 70 —0°78 —0°78 20 +1°24 +1°25 15 —1°03 —1-:00 25 +0°97 +1:00 80 —1°31 —1°25 30 +0°74 +0°78 90 —1°:97 — 1-90 40 +0°35 +0°38 95 — 2°49 —2 44 50 0-00 0:00 Results similar to the above have been obtained from measure- ments of a larger series of organs, and parts of organs, in Pandalus annulicornis (two races) and Palemon serratus (one race); but, at present, not more than 100 individuals of each race have been measured, and the curves of distribution of the magnitudes of the various organs are therefore more irregular than those given for the shrimp. In these cases, however, there is no constant deviation in any direction from the normal curve. There seems, therefore, no reason to doubt that an extended series of measurements will show that the variations of these animals obey the law of error as closely as do those of Crangon. I hope shortly to collect such a series of measurements. It seems, therefore, that Mr. Galton’s prediction is fully justified ; and that (1) the variations in size of the organs measured occur with the frequency indicated by the law of error; and (2) the “ probable error’ of the same organ is different in different races of the same species. I have attempted to apply to the organs measured the test of correlation given by Mr. Galton (‘ Roy. Soc. Proc.,’ vol. 45, No. 274, pp. 135 e¢ seg.); and the result seems to show that the degree of correlation between two organs is constant in all the races examined, Mr. Galton has, in a letter to myself, predicted this result. A result of this kind is, however, so important to the general theory of heredity, that I prefer to postpone a discussion of it until a larger body of evidence has been collected. CR IE IS Sal Ay SS eS a ee a Pe See a. a 454 | Prof. T. Jeffery Parker. , [Ape i7, III. “Observations on the Anatomy and Development of Apteryx.” By 'T. JEFFERY PARKER, B.Sc., F.R.S., Professor of Biology in the University of Otago, Dunedin, New Zealand. Received March 20, 1890. (Abstract.) The chief materials for the present investigation consist of a number of embryos of the three common species of Apteryx, which naturally group themselves into ten stages (A—K); an eleventh stage (LL) is furnished by a bird a few weeks old, a twelfth (M) by the skeleton of an adolescent specimen, and a thirteenth (N) and fourteenth (O) by odd bones of young birds; the adult may be con- sidered as constituting a fifteenth stage. The embryos were, for the most part, well preserved, but not sufficiently well for the purposes of exact histological study. The single embryo belonging to stage A corresponds in most respects to a chick of the fourth day. The author returns his sincere thanks to the Council of the Royal Society for the grant from which the expenses of the investigation were defrayed, and also to those who have assisted him in various ways. His paper is illustrated with seventeen plates, depicting the external form and anatomy of the various stages, and a number of new terms are proposed in the description of the skeleton. The following account is abstracted from the author’s summary of results :— External Characters-In stage C, corresponding with a sixth- day chick, there is a well-marked operculum growing backwards from the hyoidean fold, and covering the third (? and fourth) visceral cleft. A rudiment of this structure is seen in the preceding stage. In stage A, the limbs have already attained their permanent position, so that, if the backward shifting of the appendages so noticeable in the chick occurs in Apteryx, it must take place at an unusually early period. From the first appearance of the feather papille there are well- marked pteryle and apteria, most of which can be made out with tolerable distinctness in the adult. The wing of the adult has a well-marked pre- and post-patagium, and amongst its feathers may be distinguished nine or ten cubitals, two or three metacarpals, one mid-digital, and a row of tectrices majores. The barbicels of the feathers are slightly curved. | The fore-limb passes through a stage in which it is a tridactyle paw with subequal digits, followed by one in which it is a typical 1890.] On the Anatomy and Development of Apteryx. 455 wing with hypertrophied second and partially atrophied first and third digits. The nostril has acquired its final position at the end of the beak in stage E; up to the middle of incubation the whole respiratory region of the olfactory chamber, from the anterior nares to the commence- ment of the turbinals, is filled with a solid mass of epithelial cells, through which a passage is formed at a later period. At no stage is there any trace of the caruncle or “ egg-breaker”’ at the end of the beak. The Law of Growth—A number of details are given with respect to the various proportions of the different parts at different ages. The Specific and Sexual differences observable in the three species are described. The Skull.—In stages A and B the only cranial rudiments present are the parachordal plates, continued cephalad into the prochordal plate, and the visceral arches. In stage C the trabecule have appeared, and are continuous with the parachordals ; the prochordal plate sends off paired processes directly upwards in the mesencephalic flexure and laterad of the third nerves. In stages E and F the pituitary fossa is pierced by three apertures in longitudinal series—the anterior, middle, and posterior basi- cranial fontanelles. The middle fontanelle has disappeared in stage G, but the anterior and posterior are still recognisable in stages H and I. Through the anterior fontanelle the pituitary radicle passes. The medio-dorsal portion of the dorsum selle arises as a distinct chondrite, the prochordal cartilage, which in stages F and G is quite separate both from the trabecular and from the parachordal regions of the skull. None of the stages show a separate prenasal cartilage or inter- trabecular ; if present as a distinct chondrite it certainly does not extend further backwards than the anterior presphenoidal region ; the posterior presphenoidal region is clearly formed from the trabecule. In stages D, EH, and F the presphenoid is a vertical plate of con- siderable antero-posterior extent, and gives origin to a pair of large orbitosphenoids. In stage A the orbitosphenoids have begun to atrophy, and in later stages are reduced to narrow bars of cartilage, the presphenoid at the same time undergoing a great diminution in antero-posterior extent. The olfactory capsules extend backwards to the optic foracain, mesiad of the eyes; there is at no stage an interorbital septum. The turbinals are unusually well developed, and are divisible into anterior, middle, posterior, anterior accessory, ventral accessory, and mesoturbinal folds. Alone amongst these, the anterior accessory turbinal is formed as a hollow invagination of the wall of the olfactory capsule, 456 : Profi. Dv Jeflery ‘Parkers (> [Apr. 17, not as a plate-like ingrowth; its cavity contains a iim of the antrum of Highmore. There are paired, rod-like Jacobson’s cartilages, lying one on each side of the rostrum in the vomerine region, In late embryonic life, and even in the adult, the quadrate articu- lates with the roof of the tympanic cavity by a double articular surface. The hyoidean portion of the tongue-bone chondrifies late—subse- quently to stage G—and never ossifies. The Vertebral Column.—As in other Birds, ‘the atlas arises from a post-oecipital intercentrum and a pair of neurochondrites. The axis consists originally of seven pieces. In both vertebre each of these elements ossifies separately. | The way in which the notochord is constricted by the ingrowing centrochondrites differs greatly in the various regions. The atlas and axis in a newly-hatched embryo differ far less than in the adult from those of the other Ratite. Two intercentra are described in the caudal region. A new method of writing the vertebral formula of birds is adopted. , | The Sternum and Ribs.*—The development of these parts seems to show that the costal sternum does not originate by the union of all four sternal ribs, but that it extends backwards independently of the third and fourth ribs, meeting them in turn and becoming united with them by joints. In some adult specimens the sternum bears a low, median ridge, probably to be looked upon as a vestigial keel. The form of the adult sternum is very variable. } _ The Shoulder Girdle.—Up to stage H the shoulder girdle isa single cartilage; during that stage the procoracoid and coracoid are differ- entiated by fenestration. The procoracoid degenerates into a liga- ment, which is sometimes present in the adult. The coracoid fenestra may persist or may be filled up by a preaxial extension of the coracoid. Acromial, procoracoid, and acrocoracoid tuberosities are present. The coraco-scapular angle varies from 150° to 122°. In stage E the scapula is curved backwards over the ribs. In the same stage the coraco-vertebral angle is 35°; by stage H it has increased to 90°. The adult shoulder girdle is subject to great Mba both in form and size. The Fore-limb.—In the carpus a radiale, an ulnare, and the three * Tt is mentioned by the author that uncinate processes (or “ uncinates”) are’ present in the ribs of Dinornis, some points in the structure of the foot of which bird are also described. 1890.] On the Anatomy and Development of Apteryx. 457 preaxial distalia are distinguishable in early stages. The distalia usually concresce with the second and third metacarpals to form a carpo-metacarpus, with which the radiale and ulnare may or may not become united. The pollex usually atrophies at an early stage, but a vestige of it may persist. The manus is fairly constant in structure in A. australis and A. Owent, but is very variable in A. Bulleri. The Pelvic Girdle-—The pubis and ischium are nearly vertical in stages D and H, and gradually become rotated backwards. The post-ilium is already fully formed in stage D, the pre-ilium not until stage G. The pectineal process is ossified equally from the ilium and the pubis. The Hind-limb.—In the tarsus a tibiale, a fibulare, and a single distale are distinguishable in stages D and HE. In F a post-axial centrale appears in the rudiment of the mesotarsal articular pad ; in G it becomes chondrified, and in the adult ossified. A smaller pre- axial centrale is first seen as a distinct chondrite in stage L; in the adult of A. australis and A. Haasti (?) it was observed as a separate bone in the preaxial moiety of the mesotarsal pad. In stage D the fifth digit is represented by an elongated meta- tarsal; in E this has diminished in size, and in F undergone almost complete atrophy. Muscles of the Wing.—The following muscles are present in the wing in addition to those described by Owen :—Brachialis anticus, supinator, pronator, anconeus, flexor profundus internus, extensor carpi ulnaris, extensor metacarpi radialis brevis, extensor indicis proprius, and flexor digitorum profundus. There may also be a brachialis anticus accessorius, an interosseus dorsalis, and probably a flexor carpi radialis. The biceps arises from the acrocoracoid, the triceps by a long head from the scapula and by a short head from the humerus. The Brain.—The mesercephal is unusually small from the first; in stages D—F the optic lobes are dorsal; in G they become lateral by the transverse extension of the optic commissure or median portion of the roof of the mesoccele ; in H they are already ventral, although larger proportionally than in the adult. The diencephal becomes tilted backwards in later stages, its dorsal wall becoming posterior and the foramen of Monro postero-dorsal instead of antero-dorsal. The anterior commissure and corpus callosum are large. The cerebral hemispheres are of unusual proportional length, and partly cover the cerebellum. The Hye.—A pecten is present during late embryonic life. 458 On the Anatomy and Development of Apteryx. [Apr. 17, Phylogeny.—The following characters support the view that Apteryz is derived from a typical avian form capable of flight :— (a.) The presence of an alar membrane or patagium. (b.) The presence of pteryle and apteria. (c.) The presence of remiges and of tectrices majores. (d.) The attitude assumed during sleep. (e.) The presence of two articular facets on the head of the quadrate. (f.) The presence of a pygostyle. (g.) The extreme variability of the sternum, shoulder girdle, and wing, indicating degeneration. (h.) The occasional occurrence of a median longitudinal ridge or vestigial keel on the sternum. (i.) The position of the shoulder girdle and sternum in stage H. (j.) The presence of vestigial acromial, procoracoid, and acro- coracoid processes. (k.) The fact that the skeleton of the fore-limb is that 28 a true wing in stage F. (l.) The early assumption of undoubted avian characters in the pelvis. (m.) The typically avian characters, both as to structure and deve- lopment, of the vertebral column and hind-limb. (n.) The fact that the brain passes through a typical avian stage with lateral optic lobes. (o.) The relations of the subclavian muscle. On the other hand, the total absence of rectrices tells against this view. The following characters indicate derivation from a more general- ised type than existing birds :— (a.) The characters of the chondrocranium, especially in the : earlier stages. Many of these peculiarities, e.g., the absence of an interorbital septum, may, however, be adaptive, and correlated with the diminished eyes and the enlarged olfac- tory organs. (b.) The presence of an operculum in early stages. As, however, this structure has not been described in Reptiles, it either proves nothing or too much. (c.) The presence of a well-marked procoracoid in comparatively late embryonic life. (d.) The characters of the pelvis. On the other hand, in the following characters, Apteryx exhibits greater specialisation than other birds :— | 1890.] Presents. 459 (a.) The early assumption of their permanent position by the limbs. (b.) The late appearance and obviously degraded character of the hyoid portion of the tongue-bone. (c.) The position of the nostrils and the peculiar mode of develop- ment of the respiratory section of the nasal chamber. (d.) The total absence of clavicles. Such characters as the position of the basi-pterygoid processes, the broad vomer, and the presence of Jacobson’s cartilages, being paralleled in existing Carinatz, some of them even in Passerines, can hardly be considered as of fundamental importance, since they may be derived from a proto-carinate or from an early typical carinate stock. Before considering the peculiarities in the development of the sternum as of fundamental importance, it will be necessary to study that of the flightless Carinate, and especially of Stringops. The general balance of evidence seems to point to the derivation of both Ratite and Carinate from an early group of typical flying birds or Proto-Carinate. IV. “ Notes on some peculiar Relations which appear in the Great Pyramid from the precise Measurements of Mr. Flinders Petrie.” By Capt. Downine, R.A. Communicated by Sir F, ABEL, F.R.S. Received March 13, 1890. Presents, April 17, 1890. Transactions. Baltimore:—Johns Hopkins University. Circular. Vol. IX. No. 79. 4to. [Baltimore] 1890; Studies in Historical and ~ Political Science. Highth Series. No. 3. 8vo. Baltimore 1890. . The University. Berlin :—Physikalische Gesellschaft. Verhandlungen. 1889. 8vo. Berlin 1890. The Society. Cambridge, Mass.:—Museum of Comparative Zoology, Harvard College. Memoirs. Vol. XVII. No.1. 4to. Cambridge 1890. - The Museum. Catania :—Accademia Gioenia di Scienze Naturali. Atti. Ser. 4. Vol. I. 4to. Catania 1889. © The Academy. Dublin :—Royal Historical and Archeological Association of Treland. Journal. Vol. 1X. No.81l. 8vo. Dublin 1890. The Association. VOL. XLVII. i 2M 460 Presents. [Apr. 17, Transactions (continued). Eastbourne :—Natural History Society. Transactions. Vol. II. Part 3. 8vo. Hastbourne [1890]. The Society. Liverpool :—Literary and Philosophical Society. Proceedings. Nos. 41-43. 8vo. Liverpool 1887-89. The Society. London :—Odontological Society of Great Britain. Transactions. Vol. XXII. No. 5. 8vo. London 1890. The Society. Photographic Society of Great Britain. Journal and Transac- tions. Vol. XIV. No.6. 8vo. London 1890. The Society. Royal Horticultural Society. Journal. Vol. XII. Part 1. 8vo. London 1890. The Society. Society of Antiquaries. Proceedings. Ser. 2. Vol. XII. No. 4. Svo. London 1890. The Society. Society of Biblical Archeology. Proceedings. Vol. XII. Part 5. 8vo. London 1890. : The Society. Manchester :—Geological Society. Transactions. Vol. XX. Parts 16-17. 8vo. Manchester 1890. The Society. Mexico :—Sociedad Cientifica ‘‘ Antonio Alzate.” | Memorias. Tomo III. Num. 3. 8vo. México 1889. The Society. Paris :—Ecole Normale Supérieure. Annales. Année 1890. No. 2. Ato. Paris 1889. The School. Vienna :—Kaiserliche Akademie der Wissenschaften. Anzeiger. Jahrg. 1889. Nr. 19-24. Jahrg. 1890. Nr.1-5. 8vo. Wien. The Academy. Observations and Reports. Bordeaux :—Observatoire. Annales. Tome III. Ato. Bordeauax 1889. The Observatory. Cordova :—Observatorio Nacional 2S Resultados. Vol. XI. 4to. Buenos Aires 1889. The Observatory. Dorpat :—Sternwarte. Meteorologische Beobachtungen. Januar— Mai, 1889. 8vo. [ Dorpat]. The Observatory. Edinburgh :—Royal Observatory. Circular. No. 6. 4Ato. [Sheet] 1890. The Observatory. Kiel:—Commission zur Untersuchung der Deutschen Meere. Ergebnisse der Beobachtungsstationen. Jahrg. 1888. Heft 1-12. Obl. 4to. Berlin 1890. The Commission. Kimberley :—Public Library. Seventh Annual Report. 1888-89. Svo. Kimberley 1889. The Library. Liverpool :—Observatory. Results of Meteorological Observations. 1879-83. 8vo. Liverpool 1884; Report of the Astronomer to the Marine Committee, Mersey Docks and Harbour Board. 8vo. Liwerpool 1883. The Observatory. London :—Board of Agriculture.“Annual Report. 1889. 8vo. London — i h— —lC (o 4 d a 1890.] Presents. 461 Observations, &c. (continued). 1890; with Reports for 1887-88 of the Agricultural Adviser to the Lords of the Committee of Council for Agriculture. 8vo. London. Mr. C. Whitehead. Meteorological Office. Report of the Meteorological Council to the Royal Society, 1889. 8vo. London 1890. The Office. Mexico :—Observatorio Meteoroldgico-Magnético Central. Boletin Mensual. TomolI. Num. 2-4. Ato. México 1889. The Observatory. Paris:—Bureau des Longitudes. Connaissance des Temps, pour PAn 1891. 8vo. Paris 1889; Ephémérides des Etoiles de Cul- mination Lunaire et de Longitude pour 1890. 4to. Paris 1889. The Bureau. Observatoire. Annales. Observations. 1883. 4to. Paris 1889. The Observatory. Tiflis :—-Physikalisches Observatorium. Meteorologische Beobach- tungen. 1887-88. 8vo. Tiflis 1889. The Observatory. Washington :—U.S. Commission of Fish and Fisheries. Report. 1886. 8vo. Washington 1889. The Commission. ! 462 Mr. W. N. Shaw. On a Pneumatic [Apr. 24, April 24, 1890. Sir G. GABRIEL STOKES, Bart., 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 Pneumatic Analogue of the Wheatstone Bridge.” By W.N. Suaw, M.A., Lecturer in Physics in the University of Cambridge. Communicated by LoRD RAYLEIGH, Sec. R.S. Received March 31, 1890. When fluid flows steadily through an orifice in a thin plate, the relation between the rate of flow, V, measured in units of volume of fluid per second, and the head H (the work done on unit mass of the fluid during its passage) may be expressed by the equation :— H = RV? where R is a constant depending upon the area of the orifice, If the head be measured in gravitation units, R is equal to 1/2g9k?a?, where g is the acceleration of gravity, a the area of the orifice, and & the coefficient of contraction of the vein of fluid, a factor which is- independent of the rate of flow. Let us suppose a current of incompressible fluid to be drawn in suc- cession through two orifices, a, a), arranged one at each end of a closed space, B, so large that there is no appreciable difference of head between different parts of it and that the kinetic energy of the flow through the one orifice does not affect the flow through the other. By the principle of continuity, the flow V will be the same through each of the orifices, and we have for the head H, between the two sides of the orifice of entry, H, = R,V*, and for the head H, between the two sides of the orifice of exit, H, = R,V*, where R, and R, are corresponding constants for the two orifices. From the defini- tion of the term “ head,” it follows that H, + H,(=h) is the total head between the outside of the second orifice and the outside of the first. We may therefore regard H, and H, as partial heads which make up the total head h. We may suppose that the head § is due to a constant manometric depression maintained in a second large closed space, A, communicating with the first space, B,, by means of 1890.] Analogue of the Wheatstone Bridge. 463 the second orifice. If now we have a third closed space, By, likewise provided with two orifices, a3, a,, one of which, a,, communicates with the space A where the constant manometric depression is main- tained, while the other, a3, is open to the same supply of fluid as that which feeds a,, we get a second flow, V’, which we may speak of as being in multiple arc with the first, and to which the following equations apply :— H, — RV”, a, = hve H, +H, = b. H, and H, are the partial heads for the second flow, and Rz, R, the constants for the orifices as, a, respectively. We have, therefore, an arrangement for the flow of fluid analogous to the arrangement of the Wheatstone quadrilateral for the flow of electricity, the galvanometer circuit being supposed open. The head § corresponds to the electromotive force of the battery, V? and V", correspond to the electric currents in the two branches; R,, Ro, Rs, R,, to the four electrical resistances ; the spaces A, B,, Ba, take the places of the brass connecting blocks of a Post Office box or the copper connexion pieces of a metre bridge. The partial heads, H,, H,, H;, H,, correspond to the electromotive forces between the ends of the four several wires. Making contact with a key in the galyanometer circuit would correspond to opening a tube of commu- nication between the spaces B,, B,, above mentioned, and the hydro- dynamic condition corresponding to no current through the galvano- meter would evidently be the condition of no flow of fluid through the tube, and the galvanometer must be represented by some appa- ratus for detecting a flow of fluid; the detector need not, however, be designed to measure a flow any more than the galvanometer need be suitable for measuring a current. The condition for no flow in the “galvanometer”’ tube is that there should be no head between its ends; this condition is satisfied if H, = H; or H, = H,; from which it follows that the condition is entirely independent of the total head, h, and depends only on the constants of the four orifices ; we have, in fact, the ordinary Wheatstone-bridge relation :— R, == Rs Ry Ry, lf the coefficients of contraction may be assumed to be independent of the shape of the orifice, we get the condition for no flow through _ the “galvanometer ” tube :— a —-= ’ é ad % 464 Mr. W. N. Shaw. On a Pneumatic [Apr. 24, where the a’s represent the actual measured areas of the four orifices. It is evident that the practical realisation of this hydrodynamic analogue is by no means difficult. We require simply a “source” and a “sink” communicating, the one with the other, by two pairs of apertures in two separate boxes, which must be of such a size that the kinetic energy of the entering streams is practically completely dissipated in the boxes. The two boxes must also be connected by a tube in which there must be placed an apparatus for detecting the existence of a flow between the boxes. The hydrodynamic analogue suggested itself to me in the course of the study of a number of problems in ventilation depending upon the flow of air between nearly-closed connected spaces, for example, adjoining rooms. In such cases the differences of pressure which produce the flow are very minute, amounting perhaps to a few hundredths of an inch of water, and the corresponding variations in the density of air may be safely disregarded. Under such circumstances the air will follow the laws of flow of an incompressible fluid, and equa- tions identical with those quoted above will hold for the flow of air. Measurements made upon the flow of air in order to determine the coefficient of contraction have, been hitherto such as may be termed “absolute”; that is to say, the head and the flow have each been separately expressed in absolute measure and the value of R deter- mined by taking the ratio of the head to the square of the flow. This process is exactly analogous to measuring the electrical resist- ance of a wire by finding the electromotive force between its ends and the current which flows along it. M. Murgue, in a work on ‘The Theory and Practice of Centrifugal Ventilating Machines’ (translated by A. L. Steavenson), has shown that the internal resistance of a centrifugal fan to the flow of air through it can be calculated from the effects produced on the flow by varying the size of a second orifice through which the air has to pass. This process is evidently parallel to calculating the internal resistance of a battery by finding the effect produced upon the current by vary- ing the external resistance. The development of the electrical analogy seems to afford a novel method of comparing resistances to the motion of air, and of verifying the laws of flow, and one which requires only a detector and not an anemometer, and is independent of the con- stancy of the flow. Whether it could be used practically to test the laws of flow and measure the pneumatic constants for various orifices to a higher degree of accuracy than has hitherto been attained, evidently depends upon the sensitiveness of the arrangement. In order to try this, I have had constructed what may be called a pneu- matic analogue of the Wheatstone Bridge. It is represented in fig. 1, and consists of three wooden boxes, A, B,, By. 1890. | Analogue of the Wheatstone Bridge. 465 A is 4 ft. x 14 ft. x14 ft., and B, and B, are each 3 ft. x 13 ft. x 1} ft. The ends of B, and B, abut against the side of A, as shown in the figure; between B, and A is a rectangular opening, dp», 1 in. x4 in., in a cardboard diaphragm, and between B, and A a rectangular Opening, a, 1 in.xlin., in a similar diaphragm. In the side of B, at a, is an adjustable slit, made by cardboard shutters sliding in cardboard grooves, and at a, in the side of By, opposite to aj, is a similar adjustable slit. The tube connecting B, and Bay, or “ galvano- meter” tube, is a straight tube of glass, G, of about 11 inch internal diameter. It can be closed at one end by a small trap-door, D, in the interior of the box B,, which can be opened and shut by a steel wire, S, passing through a cork in the topof B,. The sensitiveness of the apparatus depends upon the indicator employed. There are many indicators that might be employed; the one I have tried and have found to work well consists of two very small parallel sewing needles, stuck through a cap of elder-pith, supported on a small agate compass centre; the needles carry very light mica vanes on one side of the centre, counterpoised by a small quantity of platinum wire. The whole is balanced on the point of the finest needle I could obtain, and forms a very delicate wind vane. When first mounted, the needles always took up a position of equilibrium with the points EE es OSS ae ss Fa ed ,.— .—-- ee .-s 466 Mr. W. N. Shaw. On a Pneumatic [Apr. 24, northward, although they had not been intentionally magnetised, nor, indeed, exposed to any risk of their being so from the time of their being purchased. They were, no doubt, very slightly magnetised, but the time of swing was very long, and the position of equilibrium not sufficiently definite. I therefore magnetised them more strongly ; the little vane then took up, in consequence, a definite position of equilibrium with the planes of the vanes approximately north and south. The apparatus being so placed that the tube, G, is east and west, the vanes always set across the tube when there is no current. The needle points enable the position of equilibrium to be ‘clearly identified by the aid of a fiducial mark on the glass tube. The sensitiveness can be altered as desired by an external control magnet, just as that of a galvanometer needle can be. The little compass needle or wind vane, M, is very sensitive to the motion of air in the tube, and although it may be possible to find other detectors that are equal, or even superior to it, yet the ease of seeing it, the rapidity of its action, and its definite zero are decidedly in its favour. The head is produced by a gas burner in a metal chimney, C, fitted to the lid of the box A. ' Various precautions are required in fitting the boxes together to secure that the air should only flow through apertures intended for its passage, but they need not here be detailed. They consist mainly in the plentiful application of glue and brown paper. The apparatus was designed when I was making a number of observations of flow of air to illustrate the theory of ventilation, and I did not anticipate that any high degree of accuracy could be aimed at. I was, therefore, agreeably surprised to find that the identification of the condition of no flow is capable of much greater accuracy than the arrangements for measuring the areas of the orifices would allow me to interpret. . Of the four apertures of the bridge, two, viz., ag and a4, are in- accessible without pulling the arrangement to pieces; they represent areas of 4 sq. in. and 1 sq. in., respectively, as accurately as a knife could cut them in cardboard. The other two areas, viz., a, and ds, are made by sliding shutters, as already mentioned. Their edges were cut with a knife, and they probably are only rough approximations to areas in a truly thin plate, so that little importance can be attached to the final results of the measurements which will be given below; they serve only to show that the width of the adjustable slit, when there is no flow through the galvanometer tube, is a perfectly definite magnitude. The following observations have been taken with the apparatus :-— 1890. ] Analogue of the Wheatstone Bridge. 467 I. To Verify the Law of Proportionality of Areas, viz., a = 8, 2 4 As already stated, a, = 0°5 sq. in., a, = 1 sq. in., so that if the law holds a, should be found to be equal to 2a,. In testing the propor- tionality, a; was made successively equal to 4, 4, 3, 1 sq. in., by the use of a cardboard wedge, 343 mm. length of which corresponds to 1 in. breadth ; and a, was adjusted till there was no flow through the galvanometer tube, and the width measured by means of the card- board wedge. The measurements were referred directly to an inch scale by parallel-jaw callipers. The observations are contained in the following table :— Table I. Area of a, in square inches "25. -50. “75. 1:00. | | 165 3387°5(?)| 495-5 [68-5 ]* Observation of width of 165 333 °5 496 [68 °5 | a3 in divisions of the 166 333 °5 495 [69 0] wedge 166 333 °5 4.94: °5 [68 -0] L165 334 494 °5 [67 -0] 0 SCR 165 °4 334°4 495 ‘1 [68 °2] Equivalents in square inches 465 985 1°46 1°92 Pe ~--4--.--.-.| 1°86 1-97 1-95 192 Q) The differences in the ratios az/a, for different values of a, are con- siderable, but it must be remembered that the greatest fractional differ- ence, being 1/19th of the whole, would be accounted for by an error of 1/76th of an inch in the adjustment of a, to + inch, and a cardboard © slit, cut with a knife, can hardly be expected to reach beyond that limit of accuracy. It is evident, from the readings given, that the condition of no flow is capable of very accurate experimental definition with the little compass detector. II. Verification of the Inference that the Condition of No Flow is Independent of the Total Head. This has only been carried so far as to determine whether, when the adjustment of areas was made, the equilibrium could be dis- * The readings in this column were taken by means of a different and wider wedge. 468 Pneumatic Analogue of the Wheatstone Bridge. [Apr. 24, arranged by altering the quantity of gas burning in the jet. No difference was, however, observed in the position of equilibrium of the needle, whether the gas was quite low, or on full, or turned out, leaving only the head due to the heat of the metal chimney. So far as could be tested in this manner, one of the advantages of the Wheatstone bridge, viz., that the adjustment is independent of the electromotive force, is correctly followed in the pneumatic analogue.* III. Comparison of a Circular with a Rectangular Aperture. A circular aperture in a brass plate, one-sixteenth of an inch thick, was balanced against a rectangular one, formed by the sliding card- board shutters. The circle was turned to be 1 inch in diameter, and the inner edge of the aperture was bevelled. The observations, when the circle was in the position a,, were— a, = wx (4)? = *785 sq, in. 489°5 Readings for az, 490 Mean, 490. 490 Whence dz = 1:446 sq. in. “3 — 1:86. “4 = 2, oy ay When the circle was in the position az, dz = “759 Sq. in. 125 Readings for a, 126 Mean, 125°5. 125°5 ‘Whence a, = °302 sq. in. oy me) The observations were repeated with similar results. These two values of the ratio a,/a, would be reconciled by assum- ing that the circular aperture was only equivalent to a rectangle whose area is 0°925 of the circular aperture, and they, therefore, throw doubt upon the idea that circular and square apertures have the same coefficient of contraction, but the rectangular apertures were * The flow of air through an aperture (a3) of 1 sq. in. amounts to about 2 cubic feet per minute when the gas is very low, and to 4 cubic feet per minute when it is full on, so that the head can be changed in a ratio of about 4: 1. 1890.) Effect of Tension upon Magnetic Changes of Length. 469 not such close approximations to orifices in truly thin plates as to warrant the acceptance of this result without apparatus of more elaborate construction. Moreover, there is a possibility of slight leak in the grooves of the shutters, which ought not to be disregarded. The observations are, however, sufficient to show that a properly constructed apparatus is capable of making measurements of the effective areas of orifices with a very considerable degree of precision. It is well known that if the orifice be not an aperture in a thin plate, but in the form of a tube, straight or bent, the flow through the orifice can be represented by an equation of the same form as if the orifice were a thin plate aperture, viz. :— H = RV?, but in the case of a more complicated orifice R cannot be so easily calculated from the dimensions; the value of R might, however, be determined experimentally for an orifice of any shape and dimen- sions by a pneumatic bridge of suitable size, and the result might be expressed, as M. Murgue suggests for the case of mines in the work already referred to, by stating the area of the thin plate orifice to which the given orifice is equivalent. The comparison of calculated values of R with observed values obtained by a pneumatic bridge would enable us to determine a number of pneumatic con- stants that are at present only comparatively roughly ascertained, such, for instance, as the coefficient of air friction in tubes of different diameters, the constants of different forms of orifice, the effect of bends and elbows in pipes, and of gauze or gratings covering an orifice. And it would not, I think, be difficult to arrange the ap- paratus in such a way as to determine the law of resistance of a disc to the passage of air and its variation with velocity. The velocity can be increased to any extent that may be necessary by using a centrifugal fan to produce the head instead of the gas burner. I am intending, if possible, to have my present apparatus altered in some of its details, so that the orifices may be more definitely expressed in terms of thin plate apertures, and then to use it for the determination of some of the pneumatic constants I have referred to. IT. “On the Effect of Tension upon Magnetic Changes of Length in Wires of Iron, Nickel, and Cobalt.” By SHELFORD BIDWELL, M.A., F.R.S. Received April 8, 1890. Preliminary. A former communication to the Royal Society (‘ Roy. Soc. Proc.,’ No. 243, 1886, p. 257) contains an account of some experiments relating to the magnetic extensions and contractions of iron wires 470 Mr. 8. Bidwell. On the Effect of Tension [Apr. 24, under tension. Wires of several different sizes and qualities were suspended inside a magnetising coil, and were loaded with various weiglits ; and in each case observations were made of (1) the smallest magnetising current which caused sensible change of length ; (2) the current producing maximum elongation (if any) and the value of such elongation; (3) the critical current which was without effect upon the length of the wire; and (4) the contraction pro- duced by a certain strong current. The results indicated that the maximum elongation became smaller as the load was increased, disappearing altogether when the tension exceeded a certain limit ; and that contraction began to take place at a correspondingly earlier stage in the magnetisation. These results were chiefly of interest as disproving Joule’s conjec- ture, which has often been quoted as if it were an experimental fact, that, under certain critical tension (differing for different specimens of iron, but independent of the magnetising force*), magnetisation would produce no change whatever in the length of the wire. The subject, however, seemed worthy of more complete investiga- tion, and I have lately undertaken a series of experiments in which the changes of length undergone by a stretched iron wire were traced continuously as the magnetising force was gradually increased from a small value up to about 375 C.G.S. units. Similar experiments were also made with a nickel wire and with a thin strip of cobalt, the behaviour of these metals under tension never having been previously studied. Apparatus. The apparatus employed was the one described and figured in my former paper. The diagram there given, together with a short description, is, for convenience, here reproduced (see fig. 1). Hxperiments. ; For reasons which need not be repeated here, it was found neces- sary to support the magnetising coil in the manner shown in the figure, its whole weight being borne by the experimental wire. The minimum load on the wire was therefore represented by the weight of the coil, together with the pull of the lever, the two amounting to 1:36 kilo. Greater tension was produced by attaching weights to the hook H. The iron used was a piece of soft annealed wire, 0°'7 mm. in diameter and 10 cm. in length, between the clamps. The weights * At least within the limits of the forces employed by Joule, estimated to range from 7 to 114 C.G.S. units. See ‘Roy. Soc. Proc.,’ No. 242, 1886, p. 112. 1890.] upon Magnetic Changes of Length in Wires. AT1 Fre. FE: 000000 ©00000000 0000000000000 ie) Q fe) le) ie] ° fe] re] 12) je) le] ie] O° ie] le] 3° fe] ie} oO ie] ie} ©0000066000 00090000000 ( 3 ' Sa rf] 2 A WwW The magnetising coil, CC, is supported by a stopper, A, which is inserted into the bottom of the coil. Through an axial hole in A is screwed a brass rod, terminating in a stirrup, 8, beneath which is fixed a hook, H, for the suspension of weights. A second brass rod, suspended by a pin at P, passes freely through a stopper, B. The wire under experiment, X, is clamped between the ends of the brass rods. The knife-edge at the bottom of the stirrup acts upon a brass lever, R, one edge of which turns upon the knife-edge D, the other actuating a short arm, E, attached perpen- dicularly to the back of the mirror M. The mirror turns upon knife-edges about its horizontal diameter. By means of a lantern the image of a fine wire is, after reflection from the mirror, projected upon a distant vertical scale and serves as an index. Dimensions:—SD = 10 mn., DE = 170 mm., ME = 7 mm, distance from mirror to scale = 4706 mm., each scale division = 0°64 mm., length of X = 100mm. successively attached to it were equivalent to 1950, 1600, 1170, 819, 585, and 351 kilos. per square cm. of section. The nickel wire was 100 mm. long, and 0°65 mm. in diameter; it was supplied by Messrs. Johnson and Matthey. The loads under ‘which it was examined were 2310, 1890, 1400, 980, 700, and 420 kilos. per sq. cm. 472 Mr. 8. Bidwell. On the Effect of Tension [Apr. 24, The cobalt used was a narrow strip measuring 100 mm. by 2°6 mm. by 0°'7 mm.; its cross section being, therefore, 1°82 sq.mm. It was not possible to obtain this metal in the form of a wire; and for the piece of thin rolled sheet from which the strip above-described was formed, I am indebted to the kindness of Messrs. Henry Wiggin and Co., of Birmingham, who had it specially prepared for me. The loads employed for the cobalt strip were equivalent to 772, 344, and 75 kilos. per sq. cm. The first of these was represented by an actual weight of 31 lbs.,* which was as great as the apparatus seemed capable of bearing without risk of injury. In all the experiments the loads were successively applied in decreasing order of magnitude, and before every single observation the wire or strip was demagnetised by reversals, without, of course, being removed from the coil. The results obtained for iron are given in Table I, and also shown in the curves in fig. 2. Those for nickel are given in Tables II and III, and in figs. 3 and 4, In fig. 3 the curve for 700 kilos. is represented by a dotted line for the sake of distinctness. Table III and fig. 4 are constructed from data obtained from a complete set of curves, like those in fig. 3; they show the magnetic contractions that would occur under increas- ing loads in constant magnetic fields of 125, 185, and 360 C.G.S. units respectively. These magnetic contractions would, of course, be superposed upon elongations of a purely mechanical nature, due to the tensional stress. The results for cobalt are contained in Table IV and fig. 5. In the figure the contractions corresponding to the various loads are indi- cated by different kinds of marks, and a single curve has been drawn as smoothly as possible through the whole of them. In all the tables and figures magnetic fields (which are those pao to the coil alone) are given in C.G.S. units, and increments and decrements of length are expressed in ten-millionths of the length (10 cm., or about 4 inches) of the experimental wire or strip. In figs. 2 and 5, therefore, the height of each little square corresponds to 1/10,000 mm., or 1/250,000 inch, and in figs. 3 and 4 to 1/2,000 mm. or 1/50,000 inch. * 14 kilos. + The apparatus used for this purpose is described in ‘ Phil. Trans.,’ vol. 179 (1888), A, p. 206. we |) hostile haa 1890.] upon Magnetic Changes of Length in Wires. = 478 Table I.—Iron. Magnetic Elongations in ten-millionths of length with loads per sq. cm. of field in’C.G.S. ) units. | 351 kilos. | 585 kilos. | 819 kilos. | 1170 kilos, | 1600 kilos. | 1950 kilos. 7 2 2 | 0 @) @) 0 ; 9 ee | ab 5 O 8) O 11. 6°5 8 oe 0 0 0) 16 14 12 8°5 2 — 1 — 2 22 20 18 11°5 2°5 — 2 — 2°5 35 27 23 14°5 3°5 - 3 — 4°5 50 26°5 23 13 2 88 25 19 9 0 — 9 —13 138 17 10 2 — 7 —17 — 24, 188 10°5 3°5 — 3 —13°5 —23 — 32 281 0 — 9 —18 —24°5 —37 —48 375 —9°5 —21 — 28 —39 —52 — 62 Magnetic Contractions in ten-millionths of length with loads per sq. cm. of field in C.G.S. units. 420 kilos. | 700 kilos. | 980 kilos. | 1400 kilos. | 1890 kilos. | 2310 kilos. | 1D 2. 2 2 0 0 0 16 4 3 2 0 0 0 19 12 5 4 0 0 0 28 30 9 8 1 2 0 34 43 22 15 2 3 2 50 69 40 27 4 5 2 69 i ‘3 a ree 8 72 102 65 58 84 st a = as i 88 123 96 73 26 12 103 142 | 123 98 43 21 13 125 162 156 122 56 30 17 159 190 | 193 165 88 52 39 184. 209 221 195 109 43 188 fe Be 45 68 219 232 245 237 152 i 60 925 Z * 2 94 275 256 275 284, 194 i 91 284. i fs f fe 127 359 “a 315 334 242 363 288 ra : Y o 140 384 ee ee | ee ee 176 St OS 6/ | itis | SO72Y, OO9/ = © [Apr. 24, wv, my O71: Mess} 4 2} + wal ut yjbuaTz fo sabuny 80724) 6/8. } ‘sopay| ~ j=) "S 3 BN > < S 3S Ry > ~S ae) ~ S “Sie 7? va oO ‘£YJU0I177 2 U- LIA Ipanbopy Mr. S. Bidwell. = : w90kilos “1700 \erlos. 980 ktlos =" 2.000": « Leer Brg one POR i ORCA Raat ety “Ss ee cea fe aA kre 2 | i Melos per 89. C7. | Mayr " > 2 a) > ~~ o> & S NY > iA) D Ss ~ S ~~ © a) SS i) oat S S 4 2 S, 3 Mra Ss o S io) + oO YIUAT fO SYIUOIDIIUM-UA) UI UOITIIDAI UO,’ ; JMO: f 7210,) ° fo) “ ou (Oot VOL. XLVII. 1890.] 476 Mr.'S. Bidwell. On the Effect of Tension [Apr. 24, Table I1I.—Nickel. Contractions in ten-millionths of length in fields of | Load in kilos. per sq. cm. | 125 units. 185 units. | 360 units. | | | PKA S: Wee 1890.] On the Heat of the Moon and Stars. 487 independent adjustment, so that ultimately the focus is in the vertical axis of rotation, and at the same time the cone of rays from the large mirror is just not sufficient to cover the surface of the flat. Though there is a finder, it would hardly be safe to trust to this to know when a star had just come on to the sensitive surface, and so I have arranged a l-inch total reflecting prism behind the metal block under the magnet, which can be turned round so as to view the sensi- tive surface, and any image in the small space round it, from either side of the box. There is an oblong hole in each side for this purpose, threugh which a low power eyepiece, carried by a bracket on the metal block, projects; the space round the eyepiece is covered in by a separate shield, to prevent hot or cold air from entering the box. The dark radiations from the pupil of the eye are entirely prevented, by the three glasses, from reaching the sensitive surface, so that it is possible to watch the image of any heavenly body quietly transit across.the disc or sensitive surface without disturbing the indications by the heat of the eye. I have arranged a temporary small telescope with a diagonal eyepiece, immediately above that of the chief tele- scope. The small telescope shows that part of the scale to which the spet of light is brought, magnified, so that without moving the body or any part of the apparatus itis possible to watch a star come on to the disc, and.to see the-effect:on the scale, and thus to avoid every source of error.at once. If in any case a star is observed to transit over.-the disc time after time, and the index is not moved through one-quarter of a millimetre (and I find on a perfectly clear and quiet night there can be no doubt whether this is so or not,—I should even have little doubt of a tenth of a millimetre), then it is certain that the heat received was not sufficient to produce such a defiection. .An equatorial star takes about 20 seconds to cross the dise, while practically the whele deflection due to any source of heat is produced in 5 seconds, and so, no matter how long the star might be kept on there would be no gain, while, on the other hand, the longer that it is necessary to leave the star on before practically the whole deflection is produced, the greater is the uncertainty of the zero of the instrument. The advantage of the short time constant, if I may use this expression, is fully proportional to its smallness, if it is not proportional to some higher power of its smallness. I determined not to put up the apparatus in the doubtful atmo- sphere of London, and I am fortunate in having been able to fix it in my father’s garden at Wing, in Rutland. The position is certainly good, the altitude is about 400 feet, the climate is as dry as in any part of England. The subsoil is oolitic limestone, containing a large quantity of iron, and very firm (the foundations of many of the old walls in the village are from 1 to 2 feet above the present level of the ground, and are perfectly secure). There is not a house or building 488 Prof. 0. V. Boys. [Apr. 24, within 100 yards, and these are screened off by trees. The only objection is the rather long railway journey, which prevents isolated observations at odd times, and makes special observations of temporary phenomena very inconvenient. The column is bolted down to a mass of about 2 tons of concrete, bedded upon the rock. The protecting house is made of wood and galvanised iron, and rests by four grooved wheels on rails made of gas-pipe, so that it can, when its own holding-down bolt is un- screwed, be pushed away so as to leave the telescope clear. The door lifts off and rests against two posts in one of the borders near. The figure will be sufficient to make every part, except minor details, perfectly clear. I think it will be best to describe the observations in the order in which they were made. I began observations on the 6th September, 1888. The night was clear, but. there was a gentle wind from the S.W., which produced an uncertainty in the position of the zero of a few millimetres. To keep off the wind I pulled the house over the telescope and looked east. Capella and Regulus gave no indication (11 20 P.m.), certainly not 4mm. There were several good negative observations. An earwig then began to climb up the delicate circuit of the radio-micrometer, and as it was windy I left, after first removing the cirenit. September 7th. To keep earwigs, of which there were an enormous number this year, and spiders from cominy into the radio-micrometer, I placed in the diaphragm tube some cotton-wool which had been soaked in creosote. Thunderstorm in the day; at night wind north and cold. Dew on the telescope. Observed many stars up to 3 A.y., including Altair, Arcturus, a, 8, and 6 Orionis,and Capella. No deflec- tion of as much as 1 mm. Wind prevented greater accuracy. About 3 a.m. some fleecy clouds passing produced strong effects of heat long before the star showed any diminution of brightness to the eye. A few leaves on the top of a distant tree produced an effect of about 60 mm. of heat. September 1ith. A new moon, just above the horizon (about 4°), produced, the instant the image of the limb met the disc, a rapid movement of about 30 mm., which gradually declined to about half when the terminator was reached, after which the defiection at once fell to nothing. There was no indication of heat from the dark part of the moon. The night being good, I was out till dawn, and tried all the bright stars in Pegasus, Andromeda, and Orion, as well as Aldebaran, Castor, Capella, and Saturn. No result from any of them, certainly not } mm. September 12th. At 5 30 p.m. the moon, first quarter, was low down in the south. Observations at 5 50 and at 5 54 in the daylight showed deflections at the limb of 125 and 120 mm., which, as before, became less towards the terminator, where they vanished. 1890. ] On the Heat of the Moon and Stars. 489 September 13th. No effect from Jupiter, but he was badly placed near the S.W. horizon, and it was too windy for a satisfactory nega- tive observation. Several observations of the moon showed the greatest heat to be close to the limb; the deflection for this part ranged from 175 to 200 mm. September 17th. Night clear and quiet; heavy dew. I now deter- mined more accurately the variation of heat from point to point across the moon by arranging that it should transit centrally (or near a pole if desired) over the disc and taking readings every ten seconds. The first five curves in fig. 3 are the results of five consecutive transits Fie. 3: P ~ ire a ee pre ff ai nN SENG FRY LLP saat wr Te ne S } oh. ~N ~ ES N) : lear, a VY | 7 | BALA \AIN LOSSES & | | 0 56; * 100 I50 200 300 Sec over the central part of the moon. The sixth curve was taken over the south end of the moon and the seventh curve over the north end. They were all taken when the moon was not far from the meridian. These are the first observations which clearly indicated a maximum of heat within the disc and not on the limb. This is evidently about the position at which the Sun is ver tical, being approximately at right angles to the terminator. To save space and confusion, these curves are all drawn superposed but separated in time to a small extent. September 19th. Full moon. The first curve, fig. 4, was taken when the heat of the moon was largely absorbed by a piece of clean window glass fixed across the mouth of the radio-micrometer. The second curve was taken immediately afterwards (95 p.m.) without glass. The heat transmitted by the glass, almost exactly 25 per cent., is somewhat different from the proportion, 17°3 per cent., which Be ger ee eg Bree ria TE a eet a | | Senes as BCR 4 Pl | ry 3 hours acre 12345678 91021254567 a Sean aan8 re " FEE Tu rpentine given eve ' Total ERPRRaRE a Lees sd) RR See {|= ARN Si SSR SEERA SaRees PN el te A PLAT x= Total=|1032"- Jan 19 th : [| : \ Jan 18 th ot Ts) Turpentine given every 3 hours. verli ne 13 71L72. Lury cae iS * with the usually accepted views of the action of medicines on the liver. Calomel—On Nov. 7th, 1888, 5 gr. of calomel were administered at 7 P.M.; a slight aperient effect followed the next morning, but, on comparing the amount of bile excreted before and after, it was found that for ten hours before the administration of the calomel, [ Apr. 24, On the 4 fan FOR RRACSHR ee 9GPLALANOESLIOGHS ZIANOLESLIOSHL 2) CINDESZOGHS 21eliolsé el ole 8 Z99v 7S L929 | (@) 7) 2 e) aa 2) > RES = me Ss < 4 — = vezlanoeslL ogre Zi noes zas+e2i 2iuol ) NOES LIGHS al PINOlEBLIOGHSelanoessgaGrec! ANa6sL9SGHEe? | 1890.] Secretion of Bile in a Case of Biliary Fistula. 505 CHART 3. Normal Secretion 24hrs.no Irtdin. Secretion 24hrs.wtth [ridin gr’ athe ant \Ap1s? Ap. 14 ys 76%% lam. p.m. p.m. lo 1212345678910 12345678910 12123456789 oNnle!2 34567 PEEET EEL LEE 7. aie = | | = ' | ! | 12 oz. 6 dr. 20 min. of bile were excreted, and that for ten hours sub- sequent to the administration 10 oz. 4 dr. 30 min. were excreted, “.e., 2 oz. 1 dr. 50 min. less. Huonymin—On Nov. 17th 4 gr. of euonymin were given at 11°30 am.; for the four hours preceding the administration, 5 oz. 4 dr. 9 min., and during the four hours subsequent to its administration, 5 oz. 1 dr. 8 min., were excreted, 7.e., 3 dr. less. This dose was repeated on several occasions with similar results. Rhubarb.—On Noy. 13th, at 11 am. 4 oz. of tincture of rhubarb was administered; during the preceding six hours 7 oz. 3 dr. 23 min. of bile were excreted, and during the six hours subsequent to the administration of the drug, 7 oz. 4 dr. 19 min. were excreted, that is 56 mins. more, in the subsequent than in the preceding six hours. But on comparing the corresponding period of the previous day, when no rhubarb was given, we find that 8 oz. 6 dr. 10 min., or 14 oz. more, were excreted. Therefore no increased flow of bile can be put down to the action of the rhubarb. On Noy. 15th, 1 oz. of tincture of rhubarb was given. The figures as seen in the tables again show a diminution compared with the previous day. Podophyllin was given on one occasion, and no cholagogue effect was noticed. Carbonate of Soda.—Soda water, aérated, was given, and produced an increased flow. Its ingestion was followed in two hours by a maintained increased flow not succeeded by a marked diminution. Tridin.—On April 16th, 4 gr. of iridin was followed by a good afternoon rise in the bile flow, but two days later there was a much higher afternoon rise when no drug had been given. On April 19th, a ee eee ee 506 Mr, A. W. Mayo Robson. ‘On the [Apr. 24, 4 ger. of iridin gave an effect not so pronounced, the increased flow being intermittent. Apparently, the action of iridin is to increase the flow temporarily, without augmenting the total quantity in twenty-four hours. -Turpentine—Messrs. Prévost and Binet state that turpentine and its derivatives promote a notable increase in the excretion. In order to test this, a turpentine capsule containing 15 min. of the oil of turpentine was given every four hours night and day. On Jan. 18th, no drug given. 27 oz. 6 dr. 35 min. were excreted in twenty-four hours. On Jan. 19th and 20th, during the adminis- tration of turpentine capsules, 28 oz. 5 dr. 41 min. were excreted, that is, an increase of 7dr. During the following twenty-four hours, the capsules being continued, 30 oz. 2 dr. 10 min. were excreted. During the third period of twenty-four hours with the capsules .26 oz. 57 min. were excreted; and during the fourth twenty-four hours 27 oz. 45 min. Therefore, although an increase was apparent on the second day, the daily amount of bile discharged in the twenty-four hours was not so much as on many days when no turpentine was being given, as, for instance, on Oct. 27th and 29th, when it was over 30 oz. Benzoate of Soda.—Messrs. Prévost and Binet state that the administration of benzoate of soda to dogs increased the amount of bile to two or three times the normal. This I do not find to be the result in Case I, as the table and charts appended will show, where no positive increase 18 seen. Conclusions. _ First.—The bile is probably chiefly excrementitious, and, like the urine, is constantly being formed and cast out. Secondly.—Though the bile probably assists in the absorption of fats, its presence in the intestine is not necessary for the digestion of such an amount of fat as is capable of supporting life and keeping up nutrition. Thirdly.—Increase in body weight and good health are quite com- patible with the entire absence of bile from the intestines. Fourthly.—The antiseptic properties of the bile are unimportant. Fifthly.— Whatever little antiseptic quality bile may have is pro- bably derived from its admixture with the gall-bladder fluid. Sixthly.—The supposed stimulating effect of the bile on the intes- tinal walls is not necessary for a regular action of the bowels. Seventhly.—The quantity of bile excreted in the twenty-four hours, during health in a person of average weight, may vary between 39 oz. 4 dr. and %5 oz. 6 dr., with an average of 30 oz., less the 24 oz. of fluid secreted by the gall-bladder. i 1890. ] Secretion of Bile ina Case of Biliary Fistula. 507 Highthly.—More bile is excreted during the day than at night, the excess varying between 5 oz. and 3 dr. Ninthly.—The excretion of bile seems to go on constantly and with great regularity. _ Tenthly.—The excretion is apparently not materially influenced by diet. Hleventhly.—The pigment of fresh human bile is biliverdin. Twelfthly—The supposed cholagogues investigated seem to rather diminish than increase the amount of bile excreted. Mr. Fairley’s Analysis. Analysis of bile drawn from biliary fistula (Mrs. V. B.), collected April 13th, 10 a.m. to 10 p.m., and April 13th—14th, 10 p.m. to 10 a.m., 1889. Columns J, II, III refer to the whole bile and gall-bladder fluid: Column I, first twelve hours; Column II, second 12 hours; and Column III, the whole fluid collected during twenty-four hours. Column IV gives the compositicn of the bile calculated without the gall-bladder fluid. E. II. Tk IV. 24 hours’ bile, 12 hours’ bile, 12 hours’ bile, corrected for 10 a.M.to10 p.m. 10P.M.to10 a.m. 24 hours’ bile, gall-bladder April 13. April 13—14, April 183—14. fluid. Quantity........ 570 c.c. 370 c.c. 940 c.c, "868 c.c. Specific gravity .. 1:0085 170090 1:0087 10086 Reaction........ Alkaline. The bile contains in 1000 parts :-— Waters... pane C8210 981°79 981°98 981°76 Total solids...... 17°90 18°21 ~ 18°02 18:24 1000-00 1000°00 1000°00 1000°00 The solid matter of the bile contains :— Cholesterin...... 0°44 0°45 0°45 0°45 Fatty matter (free) O11 0°12 012 012 Fat combined } (chiefly sodium stearate) ...... 0°90 1:08 0°97 0°97 Sodium _. glyco- . cholate ...... 7°45 7°60 (ic a 751 Sulphur equal to sodium tauro- cholate ....... 0087 0°094 0°09 0:09 Organic substances precipitated by alcohol, chiefly VOL. XLVIl. 9p 508 Mr. A. W. Mayo Robson. On the [ Apr. 24, x: II. Hi IV. 24 hours’ bile, 12 hours’ bile, 12 hours’ bile, corrected for 10 a.M. to 10 P.M. 10 P.mM.to 104M. 24 hours’ bile, gall-bladder April 13. April 13—14. April 13—14., ‘fluid. mucus and epi- thelium ...... 1:31 1°29 1:30 0°85 Chlorides equal to sodium chlo- Tide cee eee 5°08 4-91 501 4°95 Carbonates and phosphates of sodium, potas- sium, lime, magnesia, and LOU Ya lenaisaweel, eee 2°66 2°57 2°54 Coppers cstket tes minute trace eT trace SUE, os wslee spe a trace ee trace Sulphates Urea | See's |. wie none oe none Sugar The solid matter of the bile gave on ignition :— Ash per 1000 parts 8:15 8°68 8°36 8°34 The above analysis of the bile was confirmed by a further quanti- tative analysis of the bile taken five days later. The average quantity of bile as ascertained by observations extend- ing over eight months was 30 ounces (very nearly 862 c.c.) during twenty-four hours. Analysis of Fluid from the Gall-bladder (collected during 24 hours. Mrs. A.). Received April 29, 1889. Quantity 2... #20. paces oes o +4, hee Specise cravity.... 5.45455 —eeee 1:0095 Reactions... 2. 625. eine eee Alkaline. The fluid contains in 1000 parts :— Waker aces ee ere eS oe. (Cae The solid matter contains :— Organic matter, chiefly mucin with trace-of albuinen,, 307. Se eee F 6°72 Chlorides equal to sodium chloride... 5°73 Sodium carbonate: 24. cance ee ae 2°20 Other salts, containing phospkates, potassium salts, Geo... 2.5 .csen eee Ow * The solid matter was carefully dried until its weight was constant, and on ignition gave 8°64 parts of ash. 509 Secretion of Bile in a Case of Biliary Fistula. 1890.] ox ‘Snip 07 onp AT qtssod ,,“qonux os ,, Jo eseorour = snt gq Oy ‘snap 07 onp Aj qissod ,‘qonur os ,, Jo osvoroop = snuryy ol fe aE Ee = ne ee ee ee eS T “4° or P 08 Go 0 St ie is reins i Te iT4 0Z a 2 8zZ GT I a+ eo 6c eee ee iT3 O87 Beeee 0G OL see # ‘ tas 62 6 CL 9 62 OL G g as oe 13 oeroe its ata ae 9a Of SVs b= ae Se sues" -0980zTI8q BPOR VA 79 CP 0 LZ SP Mu O+ ee ce oes ee eee 6c 1Z 6¢ 1g 0 92 SI I f- ee 13 cor oer oe 6c 0Z 6 Ol 2 of 62 FP I+ ee “c oes ee ee we 6 6T “Ue ty 8-86 Sit Va Os ba SG Teese: ourqmodany, ies a -1 8 ZI Z O- TI ¢ O- P Pees 08 OAC Bie re 8 b or 9: c= (oF. 0+ 9 So emg Ch 6 vb 4 1 A 96 0 O+ 9 seeeeeecees qreqnyy L ‘AON 0€ F OL O28 ~ 7105. Tt OB ae OT A ee ee tel “UU “Ip *ZO “UIUT "Ip “ZO "MTU “Ip *ZO "SU ‘ep snotaord porsoed ‘ep ours “onap snoouvsoduteyu0 o1ted Sutpoooad oxy, : "oqyrqy YIM poyeys potrod ears ‘ i ported ‘snIg. sulnp Moy [enjoy UWIOLS MOT Ul eoUI.L0 TCT SULATOSqO Jo WOTZBIN(T ‘ONL OY} Of ONP Poldog B 19AO MOTT UT WOTYBLA A JO qUNOWW SuLMoys ofupeyog Le ee 510 Mr. A. W. Mayo Robson. On the [Apr. 24, Mrs. V. B. Age 42. Daily Excretion of Bile. - |Océ, 24— : i oz..| ai. .jomin. i2—1 P.M. Fish, 6 02.1;' pudidamig... se’ si st- o/s ott eetet ee 4, 59 1—2 aC ae L A 30 2—3 ee aie i iL 40 3—4 AP Ai ce 1 1 40 4—5 Tea, 14 0z.; bread, 53 oz.; egg, 1...... 1 a 8) 5—6 eo ee eo 7 0 6—7 on 50 A 1 3. 0) 7—8 IMGT, SE Pita. ajo c + agastme (opcirays: perenne nea 2 0 8—9 7 a 5 1 2 46 9—10 a ws : 1 2 0 10p.M.—7 A.M. Meil ley Ds UB aye soiree np np ese nh pe ee 5 0 oO Tea, 16 oz: ; bread, 5 OZ. 3» sin see eee 2 30 8—9 aie is ; 1 4, 0 9—10 = ee ae 1 2 40 10—11 Beet tea; f, Putb ieee + «aioe e's iepeeen iene eee 3 30 11—12 noon oe oe oe af 2 O oz. dr. min. Total quantity excreted in 24 hours ..... 26.2 215 From LO BSc. foulO A.M, us sisayesuncusepecks «.; MO. 16 alo », LOAM. to:1O PM)... 6.8.4. sees one Oct. 25— 10—11 Beef tea, 1 pint..... EN Ome 4 1 3 30 J1—12 noon ae ote oe 1 2 0 12—1 : 1 1 45 1—2 35 i 1 40 2—3 o6 56 iG if 2 0) 3—4 Tea, 10 oz.; bread, 6 oz.; egg, P.stee ws | & 0) 30° 4—5 46 a a 1 1 0) 5—6 Pa ate E Secretion of Bile ina Case of Biliary Fistula. Mrs. V. B. Age 42. \ Daily Excretion of Bile. Oct. 26— 10—11 11—12 noon 12—1 1—2 2—3 Broth, 18 OZ. ; pudding, L1G AR 15) 207) 48 Ahoy an Pe Bar Tea, Gen): bread, 5 OZ.3 ege, 1 rere ee Mil, Min oe RAY Sees Miotigid..'.. Receccnwese ok oiet Wear Ooz: + breads: 4402. ee ele Teg eyo. oz. dr. 0 SAE 7 G2 | a ce ee ee en oe me! 15 ae ISLC AONE) gee a ciwwcditle we etelgeiee 4 2 Saya appa Se eee BRNOCONANNAOKROHNWOADN SH d11 min. Oo co bo oOoono uu iss) On Oct. 27— 10—11 11—12 noon 12—1 1—2 2—3 3—4 4—5 5—6 6—7 7—8 8—9 9—10 10—5 A.M. 5—6 6—7 7—8 8—9 9—10 10—11 11—12 Broth, 17 oz. ; pudding, De Lk eliara seks Tea, TR on. ; bread, 5 OZ. 3 ege, 1 a ehatatee NA MEW wh ek Wind ay shades Tea, 16 0z.; bread, 5k oz.; milk, 10 oz. ee TOPE O MO EMS oa soee wake atta cake LD 8 NO Pane. GG. EO: Ae «se Chao os eb ook 14 5 el ee eS ee PNHERENOONONNFENwWHOOBE © co wooodcen OU OU mMon°oconooococoocoso H OV i 512 Mr. A. W. Mayo Robson. On the [Apr. 24, Mrs. V. B. Age 42. Daily Excretion of Bile. Oct. 29— | oz. | dr. | min. 7—8 Tea;.10 02. ..6.\vscs0 dew asing oo eee 1 2 45 8—9 Bread, © O25. 645 geese «5.0136 wie nyehe ales ene 6) 8) 9—10 Milk,-9. O74: © dj0:0\eiwiere «, a 0 Nien eke ee 5 40 10—11 -- ae i 3 1) | 11—12 noon 4 oe ia 1 1 8) 12—1 Chicken, 7 oz.; pudding, 6 oz. ........| 1 5 11 1—2 ae ee ate 1 4 0 2—3 ae 6 tf 4 0 3—4 4 a “0 ni 3 0 4—5 Tea, 15 oz.; bread, 53 oz.; egg, 1.....| 1 2 50 5—6 a ate diz 1 2 0 6—7 Milk) 12:02, 0. '0.< ais d¢. cu asia e eee | 0 57 7—8 ae ais sie = i 3 30 8—9 oe ae - i 3 57 9—10 Milk, 1002., c.. siete ate wnmpneoe =n ae 1 25 10—5 Aa: Milk, 18 oz... 0: .ocesdee ee vo cat ba aaa RO 5—6 i Be ae 1 1 50 6—7 ae ae 4 1 0 40 7—8 Tea, 15 oz: ; bread,,52-6z. 2.442402 eee 8) 35 8—9 Bread, 5} 02. a. + Shas wees 1 4 At) 9—10 da 1 2 C oz. dr. min. 10 AGM. to 10 BM. oo cs iene coe ols ele eine) eee 10 PM. to LO AM iccc oe oe ele clin eauie tel weln treo 30 6 25 Oct. 30— . 02, Gk, 2 mim. 10—11 aie a P 1 3 3U 11—42 noon | Chicken, 6 02.: o¢..%..% smu «asa «05 0 eee 3 25 12—1 ae ve ze at 2 0 1—2 ong 1 3 10 2—3 ae are are 3—4, Tea, 17 0z.; bread’<,. .%eatin 1 0 11—12 noon aS ae = 1 ak 1 15 12—1 Chicken, 64 0z.; pudding, 63 0z.......| Ll i 15 1—2 tests Ret os 1 of 50 2—3 be aie ae 1 0 0 3—4 Tea, 15 ag; bread,.6 07.5 ego, try. 1 1 30 A—5 ae iy 1 A, 0 5—6 x 4 0 6—7 Milk, Dior. 2 ag Sumas 6 0 7—8 Eunonymin, er. iss., ab? Pu ee 1 3 10 8—9 as a ats iL 2 0 9—10 a ss sila 1 i. 32 10—5 a.M. ae a = 8 1 0 5—6 ae an ote it 1 40 6—7 sie si ve 1 1 40 i—8 fea, LL oz. s bread: 4.07: _.6 sus «pieeneee 0) 0 8—9 ie i <3 1 6 0 9—10 = te : i 4, 0) TO.A. NE. GO: LO: PMT. | yal sis aw mom wh coe nea’ one ee 10 p.m. to 10 A.M. re ee 14 6 20 Secretion of Bile in a Case of Biliary Fistula. 515 1890.] Mrs. V. B. Age 42. Daily Excretion of Bile. Ben. 4— oz. | dr. | min. 10—11 GREE, ICOM... ove adn be ss 6 wien etemn armaed oem el 2 O 11—12 noon s = ae IE it 6) 12—1 Chicken, 6 oz.; pudding, 9 oz.; milk, 9oz.} 1 2 0 1—2 s ae we 1 5 0 2—3 ars ee ey. if 4 45 3—4 Bread, 3 0z.; tea, 160z.; egg, 1 ......| O 6 0 4—5 “e ee ec is 1 0 5—6 eee 0 : 6—7 - ‘ £ 0) 0 : 7—8 - Lt 2 0 | 8—9 ws wis Me 1 1 0 9—10 Huonymin, gr. uj, at 10.30 pw. ......| 2 0 15 10—5 a.m. DVS °F Unb dis dia: aleiais oe e's wieteiw mre grt) Ue 0 10 5—6 oe oy ] 0 36 6—7 ae “s 1 3 5 7—8 Tea, 10 oz.; bread, 6 oz. 1 0 45 8—9 58 ae 1 0) 8) 9—10 SSUES iy Sea a 0 0 oz. dr. min. SMe PO PM, co cco ccsweleaessainas Le 6 0 Seen AM. se kee ca atceces 12 94 36 27 1 36 Nov. 5— 10—11 a 2 0 11—12 noon a ns ae 1 8) 40 12—1 Chicken and potato, 8 oz., pudding ....| 1 + 0 2 oe Le oe 1 2 25 2—3 “8 te ca 1 i 40 3—4, Rea, 16 oz.; bread, 6 oz.; egg, 1 ......| 1 1 15 4—5 we a ae i 3 0 5—6 ae oe oe ip 2 50 6—7 ae NO OZ cise) aeveteueiata Ae ese esas pak) TL ly 0 7—8 we oe 1 0 25 8—9 0 7 0 9—10 Ne ae : 1 6 55 10—5 a.m. IMEI PE pA 4\cietsls oe haute ac 'e'e ae kenga S 4 0 0 5—6 ath ‘ia i 0 0 6—7 we ae ie 0 7 0 7—8 es NG oz ** bread 4s 07... oc chee cats bod 3 10 8—9 ; ‘ ik 2 0 9-—10 : 1 4 0 oz. dr. min. POR NENEMEOCPONE: poccecc ga eee cwepescae Lo Mh MO LUE Mero MOON.) ane anita nena saeey.s fo lO) % hO 28 1 20 516 Mr. A. W. Mayo Robson. On the — [Apr. 24, Mrs. VB. Age 42. Daily Hxercuoaneeie” Nov. 6— ; oz. | dr. | min. 10—11 MEK Si OFzwis owe sieletememneee i 4, 20 11—12 noon | Chicken and potato, 7 oz. ; pudding, 8.02. 1 2 25 12—1 7s ave 1 4 0 1—2 oe 5 1 1 50 2—3 sie <- aie 1 1 0 3—_4 Tea, 10 oz. ; bread,.6.02, 2...0s ene eee 1 10 4—5 a - -- £ 0 0 5—6 A as ais 1 3 0 6—7 Milk, W0.025 3.5 Calomel, gr.v ..cececccccssesecceses| LF 0 0 8—9 oe Se ae 1 0 0 9—10 ote es ait 0 6 0) 10—5 A.M. Ss May eee =e 7 6 30 5—6 5 £ 0) 0 6—7 ee 0 6 30 7—8 Mensa ox bread, Ae in: «'« sie btonerell aan 7 -O 8—9 5- 2 1 2 0) 9—-10 NGI, 10-7. nhs ae eee pee aacs | a0 IO A.M, to lO P.M. 66 seeeke® (one nev siee) AD PEMFt0 DOUALMS “ites ao ea pe ale ste omens 13? Sie we 2 Ae At 7 P.M. calomel, gr. v, 10 hours ai oo Lo Yen eze 10 hours after .. ‘ .o» 10) A ee pes eee 10 hours ‘after on n previous day.. haat ate Waal aurea aa ater eeiere eta 9 4 10 1890.] Secretion of Bile wn a Case of Biliary Fistula. 517 Mrs. V. B. Age 42. Daily Excretion of Bile. Nov. 8— oz | ‘dx. |) min. 10—11 Ke — oS i 2 40 11—12 noon | Chicken and potato, 8 oz.; milk, 8o0z.;} 1 0 8) gravy, 1 oz. 12—1 chan, AG es 1 2 0 1—2 5: sa ne 1 1 30 2—3 nai ale 4 1 4 0) 3—4 Tea, 19 0z.; bread, 24 oz.; egg, 1.....| 1 1 25 4—5 es az. a 1 1 55 5—6 aa of aie 1 3 20 6—7 ws ae aa 1 2 0 7—8 ai 213 ea 1 4, 0 8—9 ae ae ne 1 1 0 9—10 a as ae 1 0 20 10—5 A.M. MG AEG O25) cae s's a Crane sia os Sere ee 6 ) EEO EM ce eee cen cent eenssse, LO O 10 Pee COO ACM. o. ccs avscwescascaae , 1a 6 25 27 6 35 Nov. 9— ‘ 5—6 ate 1 1 50 6—7 ee =. als 1 2 O 7-—8 | Tea, 19 oz.; bread, 43 oz. ...... p.tiecaeertoonk 1 55 8—9 as mo oe 1 3 40 9—10 MEMO OZ. .eseee auelaietare aisle cistee ace ano 7 O 10—11 a sf ay. 1 il! @) 11—12 Chicken and potato, 8 0z.; pudding, 80z.| 1 1 15 12—1 28 oe ale 1 lt 45 1—2 rs we , 1 2 0 2—3 ere aA oe if 1 30 3—4 Mea, V2 on%s. bread, 4% 02. 0)» .a62) vests 1 4, 0) 4—5 Se ars ie 5 0 5—6 a 1 1 25 e¥ Rae a: 7—8 ‘ i 1 0 0) 8—9 = 1 2 0) oz. dr. min. 9 A.M. to 9 P.M. @eecetoo4eeese@eene@@ee ee eee 6 @ 12 5 ‘ 5 avr. + 518 Mr. A. W. Mayo Robson. On the [Apr. 24, Mrs. V. B. Age 42. Daily Excretion of Bile. 0Z; | 2a%: | min, 9—12 noom:— | Mal 1 pimb. oa oie oe vcs ieieta ota en eee mee 4 0 12—1 Meat, te 1602. water, 1007. 5747 1. eee 3 2 1—2 ws a iL 2 2 2—3 ae yok 3 aL 3—4 Tea, 20 02. ; ; bread, 2 o7. sis oa poder Cee 4, 2 4—5 : 1 6 3 5—6 , il 6 2 6-—-7 : ig 4, 1 7—8 - 1 4 2 8—9 : ois 1 2 i: oz. dr. min. 9 A.M: 10-9 PLM, secs +s 00 some ccs ween Ome Nov. 13— 5—6 A.M. te ve oe i 3 0) 6—7 a aN 5: if 0 10 7—8 a 7 5 Se!) Tea, 1 pint ; “bread, “A 0%. sescccsocece| 1 4 | 4 9—10 a 1 4 3 10—11 Milk, 10 oz. Woe coo 1 i 11—12 Tinct. PEL, 388... o,.5 s naieieie eee ee 6 5 12—1 Meat, &c., 16 oz.; water, 1002. .3...90) 2 1 1—2 sie 35 : 1 0 2 2—3 1 0 0 3—4, a6 oye Me 1 6 3 4—B5 Tea, 1 pint ; bread; 1 0z. So)... + sean 6 8 5—6 as ts Me it 0 8 6—7 a Se 2 1 2 6 7—8 Milk, 15 0z.; bread, 2°02. 16s. oes. Soe 0 0 8—9 a6 ye sie 1 i 8 9—10 4 ie 2 O | Se ee oe ee OP er 2) At 11, tinct. rhei, 3ss. LL A.M oto 5 PIM, cone hs how bob ono ol GQ AM. GO OPM, sieves 02 o6 nucle Bie aie chain ere ene (Cf. 9th and 12th November and 14th and 15th November.) 10 a.m. to 10P.M.. wie wees, e eon faim peer 10 p.m. to 10 A.M., AGE Jasasaned.t Nov. 14— oz. dr. min. 6 A.M. to 6 P.M. eeoeoeotceeeseseeeeeeseeeee 16 6 37 9D A.M. tO 9 PLNE. siete aver diace-e Sunoiw eel els ee. oe eC ALN, Bota PR NES) ea ol aig oer ae Slecauereie 9. 6. ee | 12 A.M. to'6 PLM. 2... Mee cos cece ene» LO eae 1890.] Secretion of Bile in a Case of Biliary Fistula. 519 Mrs. V. B. Age 42. Daily Excretion of Bile. Nov. 15— OZ. | Ga i mim, 6—7 a.m. oi 1 2 0) 7—8 Ae ei 6 4, 8—9 Tea, 20 oz.; bread, 2 oz. 1 0 8 9—10 ‘is ie ss 1 0 5 10—11 NOG Zs ose eis ats sclera 1 6 10 Pi—12 Tinct. niet, 24 a egnarenalll ral 0 6 12—1 Meat, &c., 12 oz. Cee ‘10 < Obs. wmidy are ie | eel 2 4 1—2 a a ea ul 2 0 2—3 <3 =e ee i 4 2 3—4 aig ihe ws 1 2 8 4—5 Mes. 20ers bread, 14/07. 'os coesisane| 1 0 10 5—6 we ue ° 1 1 (0) 6—7 : ate a i Ui. 3 7—8 Miike Ms oz.; bread, 107. s.%%. the potential in the glow proper, « a constant, and « the distance from the kathode. The potential of the kathode is taken as zero. The formula is not meant to be more than an approximate one, but within the limits of error of experiment the formula may be taken as correct through the dark space and the inner parts of the glow. It may, in the first. place, only be considered as an interpolation formula, and others might be found representing the facts equally well, but the equation gains some reality owing to the fact that « for a given pressure is found to be very nearly independent of the strength of the current. The complete account of my experiments will show how far this is. correct. Owing to the circumstances of the case, the fall of potential * ‘Phil. Trans.,’ 1883 (vol. 174, p. 477). , 2R 2 542 Mr. A. Schuster. could not be altered more than in the ratio of one to two, and it is not possible to tell, therefore, how far the above will express the results for a greater change in the current density. The constancy of « depends on the fact which I have verified within these limits of currents, that the potentials at different points of the negative glow all vise and fall in the same ratio when the current is altered, the kathode being at zero potential. From the characteristic equation for the potential, which in our case reduces to in which v stands for the velocity of light, we may now deduce p, or the volume-density of electricity near the kathode. The law which I have given above suggests at once that pis a linear function of V or its differential coefficients, for 1t implies that if V is any solution of the characteristic equation, XV must also be a solution. The question will be discussed in the complete account of these ex- periments, and it is not necessary to enter into it here. From equa- tion (1) we derive ; Aretp = "Ve 3 ons oe re (2.), which shows that the kathode 1s covered with an atmosphere of positively charged particles diminishing outwards in volume-density. The law of variation of density is the same as that found in the atmosphere near the earth’s surface; but the mathematical conditions are very different. The gravitational force near the earth is sensibly constant, while the electrical forces near the kathode vary as much as the density. If the curve which connects V and z is plotted, its curvature, and therefore the electrification, can be traced through the dark space and into the negative glow, but inside the glow it rapidly diminishes. The formula for p does not lay claim to more than an approximate expression of the facts, which may, however, in default of more accurate knowledge help us to form some idea of the distribution of* volume-density. Hven though (1) may hold with considerable accuracy, (2) may not give correct results for those parts of the glow which are close up to the electrode; for the curve representing V near the origin is a very steep line, slightly curved. A small change in the curvature will make a considerable change in p, without affecting the main curve to an appreciable extent. It seems prob- able, however, that the electrification continues to increase up to the electrode itself, and that the formula will express the main features of the distribution. When the lines of flow are radial the law of distribution of volume-density is less simple, but the general result is the same. : The Discharge of Electricity through Gases. 543 It is interesting to gain some idea of the charges in absolute units which are involved, and of the number of charged ions taking part in the discharge according to our theory. The electrification at the surface according to (2) is Vox?/4zv?. In a series of experiments in which V, varied from 672 to 1330 volts, and the current between 400 and 3000 microampéres, «?V) was found to vary between 3 x 10! and 1013 C.G.S. units. Taking the highest value, we find p = 1079 C.G.S. electromagnetic units, or about 30 electrostatic units. From this I calculate that the mass of electrified atoms per unit volume is 7 x 10-18, on the supposition that the charges are carried by nitrogen-atoms. The density of nitrogen in the experiment which forms the basis of this calculation is 5 x 1077, so that even close up +o the electrode the surplus of positive ions is very small compared to the number of atoms and molecules present, only about one molecule in a million being decomposed. Further away from the kathode the relative amount of charged to uncharged particles is considerably smaller still. The volume-density, which is derived from calculation, gives us, of course, the difference only between the sum of the posi- tive and the sumof the negative charges. The value of this excess of positive charges cannot therefore be taken as a measure of the total number of ions present, except perhaps close up to the electrode. In how far the positive charges in the polarising layer and the negative charges projected away from the kathode are alone sufficient to account for the whole current, cannot be decided at present. The mutual repulsion of the particles within the atmosphere of positive particles which surrounds the kathode explains at once the tendency of the glow to spread all over the surface of the electrode. Other important facts, such as the effects of an anode near the kathode in driving away the glow, will also find their natural explanation. The spreading of the glow over the negative electrode is the cause of a series of peculiar differences which appear at the two poles even in the case of discontinuous discharges. The differences observed in Lichtenberg’s figure and in Priestley’s rings, according as the dis- charging point is positive or negative, seem to me to be readily ex- plained by the atmosphere of positive ions which always tends to spread all over the kathode, while the discharge from a positive elec- trode is confined to the points of maximum electric density. It will lead me too far to enter into these questions here; but one objection must be met: why does this positive electrification not make itself apparent by electrical action in the space outside ; and why do elec- trified bodies outside not act on the glow ? As regards the first question, the charge is not really a large one. The whole quantity of electricity in the glow per square centimeter cross-section would, according to the formula, be— 544 Mr. A. Schuster. aV[, Ta | Adv, where dV /dz stands for the fall of potentialat the kathode. In my ex- periments this quantity has been smaller than 10!*C.G.S., so that the maximum total charge per centimeter cross section would ammount to about three electrostatic units. The effect of this electrification would be completely hidden by the charges on the outside of the glass tube, which cannot be avoided when we are dealing with a thousand volts. In fact, the leakage over the glass will act as an electrical screen. | It also appears that electrified bodies outside cannot produce any effect on the inside of the tube, because it can be shown from my previous work that the surface conditions in the interior of a gas through which a discharge passes render a normal force at the surface impossible. Hence no lines of force can pass from the out- side to the inside. If an electrified body is approached, a momentary redistribution of the surface charge inside the vessel will take place; but after the readjustment no further effect can be observed. It is generally stated that a greater electromotive force is required to start a discharge than to maintain it after it is once started. This statement requires qualification. The fall of potential in the positive part of the tube is of course much smaller during discharge than it was just before, but it does not follow that the rate of fall at the negative electrode is less. .In one experiment the rate of fall at the kathode at a pressure of 6 mm. was 9000 volts per centimeter, while the whole of my battery only had a difference of potential of less than 2000 volts. According to De la Rue and Miller, it requires a fall of about 1800 volts to start a discharge between two parallel plates at a pressure of 10 mm. Their measurements do not extend to smaller pressures, but a discharge would be started at the pressure of about 5 mm. by a less electromotive force than at a pressure of 10 mm. It follows that while the discharge is passing, in most if not in all my experiments, the fall of potential was much greater than that required to start it, and if we adopt the view that the breaking down of the insulation is in part due to a decomposition of the molecules, it follows that the molecules must continue to be decomposed during the discharge. This we shall find to be a result of importance. The charge on platinum electrodes in liquids is much greater than the charge on the surface of the kathode in a gas; with the usual data I make it about 10,000 times greater. This would explain the absence of observable polarisation in the case of the gas discharge, but 1f seems surprising that any electricity should pass at all under the circumstances, between the gas and the electrode. My calcula- tions, however, depend on the extension of an experimental formula The Discharge of Electricity through Gases. 545 up to the electrode, which may not be justifiable; but another expla- nation is possible. If we ask at what distance from the kathode igs the potential 1 volt less than at the kathode itself, we find it to be about the thousandth part of a millimeter. It will constantly happen that particles will approach the kathode from that distance, and the work which has to be done in the transference of the positive ion to the electrode may be partially supplied by the energy acquired in the fall. Hiffect of a Magnet on the Negative Discharge. Confirmation of the Theory. In my former paper I described a method by means of which I hoped to be able to measure the charges carried by the ions, and thus directly to test the truth of the theory. It is clearly most desirable that this should be done, for if it could be shown that the molecular charges are the same as those carried by the atoms in electrolytes, all further doubt as to the correctness of the view which I advocate would vanish. I have met with very considerable difficulties in the attempt to carry out the measurements in a satisfactory manner, and have only hitherto succeeded in fixing somewhat wide limits between which the molecular charges must lie. According to one theory, particles are projected from the kathode. The observed effect of the magnet on them is exactly what it should be under the circumstances. The path of the particles can be traced by means of the luminosity produced by the molecular impacts. If the trajectory is originally straight, it bends under the influence of @ magnet. The curvature of the rays depends on two unknown quantities, the velocity of the particles and the quantity of electricity they carry. If the particles carrying a charge are moving with velocity at right angles to the lines of force, the radius of curvature r is determined by the equation mv e v —— = M Ba ap gio ola whe) cece ee ve OF = a ad where m is the mass of the particle. If the particles originally at rest, start from the kathode at which the potential is taken as zero, and arrive, without loss of energy, at a place where the potential is Y, we should have another equation, namely :— Kliminating v, we find :— 546 Mr. A. Schuster. The quantity e/m thus obtained can be directly compared with the known electro-chemical equivalents. The assumption that in the passage of the particles, the whole work done appears as accelera- tion can never be perfectly realised, and experiments only can decide how nearly we may approach it. In the dark space surrounding the kathode the dissipation of energy is probably small, and we have every reason to believe that there the velocities are very high. Ineed not enter here into the many experimental difficulties which I have encountered, and which I hope soon to overcome more completely than I have yet been able to do. In the experiments hitherto carried on equation (2) cannot be assumed to hold. The equation (3) may be used, however, to fix an upper limit for e/m. A lower limit can be calculated as follows :—As long as the effect of the magnet on the particles projected from the kathode shows any directional preponde- rance, we may take it that the velocities of the particles must be greater than the mean velocity in their normal state. For it is clear that, if distribution of velocities was symmetrical in all directions, the magnet would have equal and opposite effects on the charges which move in opposite directions; and if by mutual impacts the velocity is reduced to its normal value, it will also have lost any directional inequality. We may obtain a lower limit for e/m if in equation (1) we calculate é 1) a == ———~- eeoveeseeeeeeeee © 8S ee 8 8 @ 4, e > m Mr oe by putting for r the smallest radius of curvature which can with certainty be traced in the glow, and for v the mean velocity of the particle, according to the kinetic theory of gases. In an actual experiment M was 200; r diminished with increasing distance from the kathode. The greatest value which could with certainty be measured was about 1 cm. V was 225 volts at the same place. Taking these numbers, we get for the upper limit ne Pg he e008 Mm In the glow the radius of curvature is quickly reduced to about + cm., showing that the luminosity is directly due to a conversion of directional into thermal motion. The gas in the actual experiment was nitrogen much contaminated with hydrocarbons. The value of the mean velocity in the state of equilibrium will depend on the supposition we make as to the nature of the particle which carries. the charge. It will be sufficient to consider the cases indicated in the following table :— The Discharge of Electricity through Gases. 5AT Nature of particle. Velocity of mean square. Eigirocen, atom... 6. ee ks ss 26 x 104 Hydrogen molecule ....... wishes hawt 104 iat reer aos: «092 a) y's aia S62) ieee ee Os Botromen; molecnle. so)... leis ees oo, 104 As we are only dealing now with the order of magnitude, the temperature need not be taken into account, and we may take v to be 10°; we thus obtain i Wa Le m The actual value of e/m is 10* for hydrogen and 0:7 x 10? for nitrogen, if we imagine each atom of nitrogen to carry the same charge as the atom of hydrogen in water; but, as nitrogen may unite with these atoms of nitrogen we must assume three charges at least to be carried, which would make e/m equal to 2 x 10%. It thus appears that there is nothing in the actual facts which is in any way not in harmony with the theory. The lower limit for e/m comes very near the actually observed values, and it is not astonishing that the upper limit yields so great a value. It will be seen that in equation (3) the radius of curvature enters as the square. I think I may take the experiments hitherto recorded as a confirmation of the theory. Assuming the theory to be correct, they show that in the glow the particles are quickly reduced to a velocity of the same order of magnitude as the mean velocity in an unelectrified medium. If the particles do not carry fixed charges, they must become electrified by contact at the electrodes. This is the view generally taken, and it is interesting to trace its consequences. The change e of a sphere touching a plane charged with surface density o is* given by e = $73a2e = 20 a’o approximately. Substituting for o the highest value which I have obtained in my — experiments, about 2°5 electrostatic units, e would be numerically equal to 50a*. If for a? we take about 5 x 107!°, which is the molecular range obtained from experiments in gases, we should be above the mark. This, when substituted in the above, gives for e the value 107!” in electrostatic units, instead of 107), that is, the charge would be about 100,000 times less than according to our theory. Applying the equation (4), I calculate that, according to the hypothesis of electrification by contact, the average velocity of the molecules would only have been 2 cm. a second, which is a reductio ad absurdum. * Maxwell, vol. 1, p. 257. 548 Mr. A. Schuster. Some Questions relating to the Positive Discharge. There is one theory of electric discharges which, as a scientific curiosity, is of interest. It asserts that a perfect vacuum is a perfect conductor, but that the molecules flying about the vacuum impede the passage of the current. If no discharge actually passes through highly rarefied gas in an experiment, it 1s, according to this view, because there is a resistance at the surface of the electrodes. It is interesting to speculate what the world would be like if this theory was true. It is perhaps not fair to urge that we should live in per- petual darkness, because the upholders of the theory could not con- sistently adopt the electro-magnetic theory of light, whose essence is a stress in the medium. But I do not see how we should have any elec- trostatic effects at all, at any rate in highly exhausted vessels. In order that gold leaves should remain divergent im vacuo, itis by no means ne- cessary that no escape of electricity should take place from them. They will collapse, though their surface may be perfectly impermeable to the discharge, as long as currents may flow in the surrounding medium. If the gold leaves are charged positively, negative electricity would flow towards them, cover them, and protect the leaves, so as to prevent any repulsion. There are other fatal objections against the theory which will survive nevertheless, for, like all paradoxes, it has an irresistible attraction to a great many minds. The following experiment has convinced those to whom I have been able to show it that the discharge consists of a diffusion of charged atoms or molecules. The apparatus used is that by means of which Balfour Stewart and Tait have carried on their researches on the heating of a rotating disc i vacuo. In front of an ebonite disc, electrodes were introduced so that the line joining them was parallel to the plane of the disc, viz., one electrode opposite the centre, and the other opposite the edge of the disc. When the latter is rotated, it carries round with it the air in its neighbourhood. If the current consisted of a motion of the medium, the particles of air could not affect the distribution of the lines of flow. But it is found that the discharge is drawn up or down according as the motion of the air is upwards or downwards. The curves formed by the dis- charge are similar to those observed when a magnet acts on a positive discharge, and their cause is identical, as the magnetic force also acts on the particles, and tends to draw them through the discharge, as I have explained in my previous Bakerian Lecture. Photographs of the actual appearance have been taken, and will be given in the full account of these experiments. Itis very striking to see the discharge steadily and slowly deflected by the rotating dise, and so sensitive is it to slight currents in the air, that the heating of the gas by the discharge and the convection currents formed in The Discharge of Electricity through Gases. 549 consequence are quite sufficient to cause a decided bending: even without any rotation of the disc. Magnitude of some of the Quantities involved in the Discharge. As it is necessary to bear in mind the order of magnitude of some of the quantities involved in the discharge, I may briefly note some of the most important ones. The most probable value for the charge carried by each atom of hydrogen I find to be 3 x 10—*8 electro-magnetic units, more generally, say, 3«X 10-23 where « is a numerical constant. Question I:—How does the energy acquired by an ion between two impacts compare with the average kinetic energy of a molecule? Answer :—The ratio e/m for hydrogen is known to be 10* approxi- mately. If a particle of mass m carries a charge e, the velocity generated from rest through a range in which the aso of potential is V is or 140 /V. 2eV m If V is one volt, this would be equal to 14x10°; a quantity nearly ten times as great as the mean velocity of a hydrogen molecule. In the positive part of the discharge when the velocity of diffusion is uniform, the fall of potential in my experiments was, roughly speaking, about 1 volt per millimeter; the mean free path calculated according to the kinetic theory varied between 4 mm. and +mm. Hence, on the average, the velocity generated in the atom by electric forces between two encounters exceeds several times the mean velocity in the stationary state. It will appear that the number of atoms carrying charges is small compared to the total number; so that the actually observed rise in temperature need not be considerable. At each impact the atom must give up, on the average, that proportion of its own velocity which it gains during © two encounters; and the above numbers show that the energy communicated is very considerable. Hence the luminosity of the positive discharge. Hvenif by an impact the ions are thrown back, the electromotive force will, in general, be strong enough to reduce it to rest, and send it forward before the next impact. The path of particles will therefore not be straight, and the velocity of the ions before impact will almost entirely be in the direction in which the force acts. ! Question II :—If the molecules, each charged with a quantity of electricity e, approach each other with a velocity equal to the mean speed in a homogeneous gas at ordinary temperature, at what distance from each other will they come to rest ? 550 Mr. A. Schiieter, Answer:—If v is taken as 17x104, and e = 38«x10-*3, the distance is 2«x10-§, which is larger, though not considerably so, than the molecular distance. We conclude that two particles charged with the same kind of electricity will, in general, not approach each other sufficiently near to bring other than electrical forces into play. Question III:—At what distance is the force between two equally charged atoms equal to the force in a field in | which the fall of potential is 1 volt per centimeter ? Answer :—r = ./3«.10-*, If the fall is 1 volt per mm., the distance would be three times as great, or about 5 x 107°. Question IV:—What is the proportion of ions amongst the molecules in the positive part of the discharge ? Answer:—I assume, as a first approximation, the velocity of diffusion to be that of the mean velocity of the gas in the normal state. (One measurement of the magnetic deflection in the glow shows that the velocity of diffusion cannot be much greater, and the answer to Question II shows that it cannot be much smaller.) If S is the cross-section of the tube, C the current, and » the number of ions, we have nSev = C; Nm = p, where N is the number of undecomposed molecules, and p the density of the gas. Combining the two equations : n mC N S.ev.p’ Ina typical example, p was 5x107-7; C=3x1074; S = 2; and as: a = 104 we find m n[N = 2 x 10-8, a small fraction, which is suggestively near the fraction obtained for the proportion of positive ions in close contact with the kathode ;, the two results being observed from altogether different quantities. Question V:—What is the average distance between the ions in the positive part of the discharge ? Answer:—With the same data as in Question IV, I find for the average distance approximately 10-*, or 75 mm. Probable Explanation of the Fall of Potential observed at the Kathode. In carrying out the investigation of which the experiments: described in this paper form a part, I have always attached most: The Discharge of Electricity through Gases. dol importance to the clearing up of those questions on which the mathematical analysis of the subject will have to be based. From this point of view, nothing is of greater importance than the investigation of the surface conditions which must hold between the gas and the vessel, and between the gas and the electrodes. Ina previous paper,* I have shown that at any part of the surface of the gas through which no electricity passes the normal forces must vanish, which is not a priori evident, if we consider the gas to possess a certain dielectric strength. The fall of potential at the kathode must depend on the surface conditions which hold there, and the following considerations may help to clear up the question. Imagine, in the first instance, a gas containing a certain number of charged particles, and enclosed in a vessel kept at zero potential, but having a surface impermeable to electricity. We may not be able to realise these conditions, but we may discuss the problem as an ideal case. How will the charged particles arrange themselves under the influence of their mutual forces? They will, no doubt, travel outwards towards the surface, but will they cling to the surface, condensing, as it were, to form a layer against the solid surface resembling a liquid more thana gas? Or will they form a gaseous atmosphere, diminishing in density from the surface outwards? Or, finally, will they resemble the state of a liquid in contact with a gas, that is to say, will they be in a state of movable equilibrium, a certain proportion always clinging to the surface of the solid, others flying away until brought back by impacts and electric forces? I do not see how the answer to these questions can be given on the theoretical grounds only, and it seems to me that experiment only can decide it. Nor is it necessary, to my mind, that an atmosphere of positive ions should behave exactly in the same way as an atmosphere of negative ions. The only consistent theory of contact electricity we possess 1s that worked out by Helmholtz, according to which we must, in calculating the work done in the transfer of | electricity through a surface, not only take account of electric but also of electro-chemical forces. There are various ways of expressing the same fact. We may say that there must be a definite attraction between matter and electricity, or we may say that the potential energy of a system contains terms involving both electrical and chemical variables, or, finally, that both chemical and electrical forces are due to stresses in the medium, and that in calculating the forces we must add the displacements and not the energies. In considering the mutual action between electrified particles at molecular distances, it is quite possible, and even probable, that positive and negative electrification may affect the molecular forces * ‘Roy. Soc. Proc.,’ vol. 42, p. 371 (1887). ae, Cul Miia jae Mr. A. Schuster. in different ways. The same holds as regards the action between electrified and non-electrified particles. If the theory of electrolytic convection in gases is true, some hypothesis of this nature is necessary to explain the asymmetry of the discharge. Positive ions, according to the theory, will be delivered at the kathode, either by direct decomposition or by diffusion ; negative ions will, in the same way, appear at ‘the anode. If, as we must assume by analogy from liquids, a certain normal force is required to effect the interchange of electricities at the electrode, this will become covered, in the first instance, with the ions until the necessary normal force is obtained But we are face to face with the questions previously raised relating to the distribution of ions against the surface of the kathode. If the conditions are such that positive gaseous ions behave partly, at any rate, as a gas; if, instead of clinging to the electrode, they form ‘an atmosphere round it, the fall of potential at the kathode is explained. The law according to which their density diminishes as the distance from the electrode increases depends on an experi- mental term, as has been stated, and I have not yet arrived at a satisfactory theoretical foundation for the law; but various supposi- tions may be made, and if we may imagine the layer of positive ions to behave like a thin liquid film having a definite vapour pressure, we may easily imagine that the falling off will take place very much as it actually does. The large fall of potential at the kathode, according to this view, is not so much due to the amount of work which has to be done to effect the interchange of electricity, but chiefly to the fact that for the same surface density at the kathode the thickness of the polarising layer is greater, which must necessarily increase the fall of potential. Thus, if o is the surface density, and D the molecular distance, the fall of potential would be 4zv*Do, if the ions covered the kathode as in an electrolyte; but, according to the observed law, the potential in the neighbourhood of the kathode is given by V = WaCt oe Ee), , which gives for the surface density KV ,/4arv?, so that Vo = 4rv?e/K; but 1/« is of the order of magnitude of a millimeter, and this shows how much the fall of potential is increased by the increased thick- ness of the layer. Comparing the two expressions, we may say that the fall of potential at the kathode would be the same as in an electrolyte if in the latter case the mean distance of the polarising layer from the kathode was 1/« instead of the molecular distances. The numerical valnes for 1/« are, on the average, about six or seven times as great as the mean free path. The Discharge of Electricity through Gases. 503 According to this view we may explain why gases in their sensitive state, like flames, behave differently to positive and negative charges. A positive charge will attract the negative ions, which will arrange themselves on the surface, and the requisite difference of potential will at once establish itself. But if a conductor placed in the flame carries a negative charge, the layer within which the positive ions collect will'be deeper, and the potential of the conductor may not be sufficient to complete the layer so as to produce the necessary normal force. It also appears that, just as minute chemical changes affect the polarisation in the electrolyte, so will all similar changes affect in the same proportion the fall of potential at the kathode. If I am right, we must consider the conditions of impact between the metal and the ions, or between the gas and the ions, to be different accord- ing as the ions have a positive or negative charge, and this leads us to the next point which it will be necessary to discuss. Tf the law of impact is different between the molecules of the gas and the positive-and negative ions respectively, it follows that the rate of diffusion of the two sets of ions will in general be different ; let us see whether we can find any experimental evidence which may throw light on this point. I think there is some reason to believe that the negative ions diffuse more rapidly, and we may at once trace one cf the consequences of such a difference of diffu- sion. Looking at the positive part of the discharge, which shows no | signs of a bodily electrification anywhere, at any rate when there are no stratifications, a quicker negative diffusion means, just as in the ease of the so-called migrations in electrolytes, an accumulation of ions at the positive pole. That is to say, at the anode a certain number of the ions must recombine again to form a neutral molecule. It has already been mentioned that at the kathode we must imagine decompositions to be going on, continuing during the discharge, because we know that the necessary electrical forces are maintained there. If the discharge is steady, then decomposed atoms must unite somewhere, and, as just suggested, the reunion may take place at the anode; or it may already take place in or just beyond the negative glow. The two questions are intimately connected. If the molecules are decomposed in one part of the tube and reunite in another, the ions in between cannot travel at the same rate. What leads me to believe in a quicker diffusion of negative ions is the fact described in my former paper, that in the neighbourhood of a discharge, positive bodies apparently become neutralised more quickly than negative ones. I think there runs throughout the whole set of experiments a general tendency for the negative ions to be drawn more quickly than positive ions towards the oppositely charged bodies. Some observations on flames also point the same way. Gold- 5b5L Mr. A. Schuster. stein found, in some of his experiments, that when an electric current passing through a gas is forced through a narrow opening many of the phenomena seen near the kathode appear on that side of the opening which faces the positive pole. Jt is also known that, if a current passes through a funnel-shaped opening, the fall of potential required is greater in one direction than in the other. Finally, if the current is discontinuous, and a point on the outside of a glass tube is connected to earth, certain phenomena are seen which have been spe- cially investigated by Messrs. Spottiswoode and Moulton. All these facts I believe to be capable of explanation if we remember that, when- ever a current passes between solids of different conductivities, a certain surface electrification is necessary to satisfy the conditions of continuity. Gases do not follow Ohm’s law, and there will in all probability be an electrification whenever the cross-section alters. The different behaviour of positive and negative electrification will come into play, and this, together with the different rate of diffusion of different ions, will, I believe, be found sufficient to explain the phenomena. The effect of ultra-violet light on a negatively electrified body is probably due, as has been pointed out, to a chemical action, but we have further to assume that this action is not set up on a positively charged body. If this view is correct, we shall have to take the law of impacts between the gas and the metal to be modified in such a way that a chemical effect only takes place when the metal is charged negatively. Stratifications. It is generally considered that the most important test of any theory of the discharge is to be found in the way in which it can explain stratification. Very little is known about the circumstances which produce stratifications, and they show by their lawless be- ‘haviour that they are rather to be considered as irregularities in the discharge than as matters of primary importance. According to our view, the regular diffusion of ions in the positive part of the discharge can only be maintained by a balance of very delicately-adjusted phenomena. The two kinds of ions diffuse with different velocities; they will tend to recombine together, and will occasionally do so. If so, and if the current does not cease to be steady, we must have as many fresh dissociations as combinations in each part of the tube. It does not seem impossible that there may be several stable ways in which the current may pass. It is possible that, besides the discharge which passes as I have just explained, there may be ancther in which the tube is divided into a succession of parts in which the decompositions alternately outnumber the ‘The Discharge of Electricity through Gases. 555 recombinations and vice versé. Such a tube would show phenomena very similar to stratifications. This is only a suggestion to show that the theory may ultimately be found sufficient to cope with this diffi- eulty. At present it seems to me to be an open question whether the stratifications are ever seen in perfectly pure gases. The Dark Space. No satisfactory explanation has yet been given of the division of the appearance round the kathode into three parts: the first luminous layer, the dark space, and the glow. The division between the dark space and the glow is often very sharp, and it is necessary to discuss how the rapid change in luminosity can be accounted for. It has’ been suggested that the extent of the dark space represents the mean free path of the molecules. If particles are projected from the kathode at low pressures, comparatively few will impinge in its immediate neighbourhood, but with increasing distance the number of impacts will increase. It has been pointed out by others that the extent of the dark space is really considerably greater than the mean free path of the molecule, calculated according to the ordinary way. My measurements make it nearly twenty times as great. This, however, is not in itself a fatal objection, for, as we have seen, the mean free path of an ion may be different from that of a molecule moving among others. I cannot, however, reconcile the sharpness of the inner boundary of the glow with the explanation given. If the juminosity only depended on the number of impacts, we should expect the parts adjacent to the electrode to be dark and gradually to increase in intensity outwards. The positive ions approaching the kathode would still further reduce the difference in luminosity. I have endeavoured to ascertain the experimental conditions which determine the shape of the boundary of the dark space. The first supposition tested was, whether the boundary was always an equi- potential surface. If so, the velocity of the particle projected from the negative electrode would be the same all over the boundary, and we might imagine that the luminous appearance of the glow depends on some minimum kinetic energy which the impinging particles must possess. The darkness is, however, not limited by an equipotential surface. A large cylindrical vessel contained two negative electrodes parallel to the axis of the vessel. The anode was formed by a cylindrical wire netting surrounding the kathodes. Under these circumstances the dark space and glow present some peculiarities, which I shall describe on another occasion. The shadow phenomena described by Goldstein are beautifully seen, and can be photographed, and as the sides of the glass vessel do not interfere (as it now appears they did” VOL. XLVII. | 2s 556 My. A. Schuster. in Goldstein’s or riginal ix peemteni: I have been able to supplement his observations in several details. At present I only wish to state that the edge of the dark space is, under these circumstances, far from being an equipotential surface ; so we must look for some other explanation. We can assure ourselves in another way that it is not a certain minimum kinetic energy which determines the boundary of the dark space. In my previous Bakerian Lecture I followed others in the statement that an increase of current diminishes the thickness of the dark space; but this I find is not correct. If the dark space is carefully watched while the current is diminished or increased by altering the resistance of the circuit, it is seen to contract or expand slightly, always being widest when the current is strongest. Such an increase of current is accompanied by an increased fall of potential ; the difference of the potential at which the dark space ends can therefore be altered at will. I can at present only think of one way of accounting for the facts, but wish for the present to express my views on this point with due caution. From the magnetic experiments iti appears that the velocities of the molecules are reduced quickly in the luminous glow, but not at any rate to the same extent in the dark space. If that is the case, there must be some change in the law of impacts, as we pass from the dark space into the glow; and the simplest supposition to make seems to me to be that the strength of the electric field is an important factor in the transformation of energy which takes place in the colli- sions. We may imagine that if the electric field is sufficiently strong, the ion will not lose aaah of its energy during impact, but that in a weak field the velocities are reduced at a ‘ieee quicker rate. It is clear that if the molecular forces are strong, two molecules must approach much more closely together before their mutual action comes into play, and therefore what must be considered an impact must happen more seldom in a strong than in a weak field. Near the edge of the dark space the electric forces are found to diminish very rapidly, and itis a question worth investigating whether the edge of the dark space is a surface at which the electric force has some con- stant critical value. I know of no facts which are against this view, and my experiments have hitherto all been consistent with it. The slight widening of the dark space by increase of current would at once be explained if my hypothesis is correct. In the above-men- tioned case of two parallel kathodes, there is always a luminous layer in the equidistant plane between them, even when the width of the dark space due to one kathode alone extends sufficiently far to include the other. In this plane the fall of potential is easily seen to be small, and the shape which the dark space assumes seems to me to agree very well with the supposition that there is a critical rate of The Discharge of Electricity through Gases. 507 potential which determines the edge of glow. But this point must be left to be settled by future experiments. As regards the inner luminous layer closely adjacent to the negative electrode, it seems due to the positive ions approaching the kathode, and not, like the glow, to the negative ions projected away from it. This is shown by the fact that a wire placed inside this layer casts a shadow towards the kathode, and also by the distortion it experiences in amagnetic field. It is remarkable that this luminosity, due to the impact of positive ions, shows according to Goldstein, at any rate in the case of nitrogen, the spectrum of the positive part of the dis- charge. Conclusion. We may now in conclusion shortly summarise the results arrived at. A gas in its normal state contains no free ions, but, if through any chemical or physical causes the molecules are broken up in an electric field, ions form, and the gas becomes a conductor. Supposing the difference of potential of two electrodes is gradually increased, a point will be reached at which a spark will pass, that is to say, the molecules will be broken up by electric forces, the positive ions dif- fusing towards the katunode will tend to form a polarising layer of finite thickness, increasing in width as the pressure diminishes. If the discharge becomes steady, the decompositions are continuously kept up at the kathode, the negative ions being projected with great velocity away fromit. These ions will move through the so-called dark space without much loss of energy by impacts, but when, prob- ably owing to sufficient diminution in the electric force, the impacts become more frequent, the translational energy becomes transformed into the luminous vibrations of the glow. The positive ions forming an atmosphere round the kathode must have a greater velocity the nearer the kathode, where their energy becomes visible in the first luminous layer. Whether decompositions take place only at the elec- trode or through a finite distance from it is at present an open question, nor can we decide as yet whether the negative molecules projected outwards are the main carriers of the current inside the dark space. In the dark space the negative ions will accumulate and meet the positive ions proceeding from the positive part of the dis- charge. We shall expect at some point towards the outside of the glow the free ions to become more numerous than in other parts of the discharge. Here we find a small fall of potential and no lumi- nosity; this is the dark interval separating the positive part of the discharge from the negative glow. A number of ions probably reunite in this part to form molecules, and in case it should ultimately be found that positive and negative ions diffuse with the same velo- city, we should have to conclude that as many molecules as are 558 Mr. A. Schuster. decomposed at the kathode recombine in this dark interval. If, as seems more probable to me, it should be found that the negative ions diffuse more rapidly, the recombination will in part take place at the anode. If the conditions in the tube are such that the gas may divide into layers, such that in alternate strata the decompositions outnumber the recombinations, and vice versd, stratifications will form. Such is the general outline of the theory, which may have to be modified in detail, but which, I believe, has a strong element of truth in it. . The possibility of a volume electrification is denied by some of Maxwell’s disciples, who look on a current of electricity as on a flow of an incompressible liquid in a closed circuit. But there is nothing, as far as I can see, in the conclusions I have drawn from the gas dis- charges which is inconsistent with the fundamental tenets of Maxwell’s theory, however much they may disagree with the acces- sory embellishments with which that theory is occasionally adorned. There may be a volume electrification without interfering with the equation of continuity of an incompressible liquid as long as we admit the possibility of displacement currents and displacements in conductors, and I see nothing improbable in this. The ordinary equations for the currents in a non-homogeneous solid (or any solid if inequalities of temperature are taken into account) give a volume electrification which can only be destroyed by the introduction of a quantity which is analogous to hydrostatic pressure, and the sole purpose of which is to destroy all electrifications except at the surface of bodies. We know of no physical phenomena which can justify the introduction of such a quantity, which seems to me unnecessary. The existence of a volume electrification can be shown to exist when a current passes from one liquid to another floating on its surface. Chemical effects are observed in the region in which the hquids begin to mix, and these can be explained by the electrification which accompanies each change in electric conductivity. Maxwell’s equa- tions assume conductors to be homogeneous throughout; whenever we are dealing with average effects only, this assumption is justified. We deduce, in a similar way, the equations which represent the transmission of light by assuming that each transparent body is replaced by a homogeneous medium having certain properties. But although this simplification is allowable in discussing some of the phenomena, there are others in which it becomes necessary to go a step further, and, considering the structural constitution of the body, to take into account separately the effects of the medium separating the atoms, and the effects of the atoms themselves. In all branches of physics we are gradually forced by the advance of knowledge to abandon the assumption of homogeneousness, and if that is done, no further difficulty stands in the way of bodily electrifications ; for | A dae Sal . a . ; : The Discharge of Electricity through Gases. 559 we may take them to be really only surface electrifications between the atoms and the medium. I have offended in another manner against so-called modern views of electricity, for I have spoken of positive and negative electricity as real substances possessing a separate existence. I have tried to place myself, however, under the shelter of recognised authority by quoting at the top of this lecture Helmholtz’s saying that we have as much ground for the supposition that electricity has an atomic con- stitution as we have for the atomic constitution of matter. We must trust to the future to bring this view into harmony with the electro- magnetic theory of light, which may be accepted now as an established fact. There is no real antagonism between the two views. If ever we are able to explain chemical and gravitational attraction by the stresses in a medium, we shall still find it convenient to speak of atoms and molecules; and in the same way the belief in an electric strain and stress is consistent with a belief in something in the atom from which the strain proceeds, and which may be taken as the elementary quantity of electricity. Hven taking the extreme view that electric stress is due to vortex filaments in the ether, we need only assume all these filaments to have the same intensity, and some to end at the surface of atoms, in order to reconcile apparently antago- nistic views. But there is no need to commit ourselves at present to any particular ideas. In some electric phenomena we shall find it most convenient to speak of electric strain and stress (displacement I think to be a misleading term, which, however, has come too much into use to be dispensed with); in other, and at present more numerous, cases, we shall still continue the old nomenclature, and speak of positive and negative electricity as real quantities. The subject of electro-chemistry is one of primary importance in the pre- sent state of science. The different behaviour of positively and nega- tively electrified particles points, as I have tried to explain, to an unsymmetrical modification of molecular forces by electrification. It is not sufficient to add geometrically the effects of molecular and elec- trical action, but it is necessary to take account of the interference between chemical and electrical forces. The exact nature of this interference must partly be solved by chemical investigation, but the discharges of electricity through gases still promise a rich harvest to the investigator. Appendix. “The Discharge of Electricity from Glowing Metals.” By ARTHUR STANTON, B.A. Tt has long been known that certain bodies undergoing chemical decomposition are capable of discharging electricity through the 560 Mr. A. Stanton. surrounding air. A few desultory experiments were made in Dr. Schuster’s laboratory, during the hot days of summer about two years ago, as to this discharge when the body was decomposed in the focus of alarge concave mirror. The method, depending on excep- tionally brilliant weather, is necessarily inconvenient in this country. Subsequently, during the Long Vacation, I made experiments in the same direction, and tried to use a piece of hot metal for the supply of heat to effect dissociation. These attempts led to an observation of the conditions under which a hot electrified piece of copper or iron could retard a charge of electricity at a good red heat. I observed in my first experiments that if a copper soldering bolt, heated to full redness by a gas blowpipe, was placed on an insulating stand and negatively electrified, discharge took place very rapidly, and occurred so long as the bolt remained visibly red; that if the bolt was repeatedly heated in an oxidising flame, and electrified, discharge became continuously slower, and that ultimately the copper was capable of retaining a charge perfectly at a full red heat. I the copper bolt, being in the state last described, was allowed to cool completely, the oxide of copper chipped off, and the metal, on heating to redness, behaved generally as at the commencement of the experiments. An iron bar was found to behave similarly. The experiment was afterwards repeated, with the substitution of a wire kept hot by a current for the massive bar of metal. In the later form of the experiment, the hot body was connected to earth, and the discharge of an electrified conductor in the neighbourhood observed. The wire was wound upon a mica frame with thick copper terminals, which served to give the frame rigidity ; the other electrode of the system consisted of a clean flat copper plate, at a distance of 2 or 3. cm. from the frame. The wire used varied from 0°3 to 0°5 mm. in diameter, the length being about 60 cm. Both the frame and the flat plate contiguous to it were enclosed in a glass or cylinder surrounded by water to keep it cool, and provided with tubes for the introduction of gases. The following are the results obtained :— First, if the conductor contiguous to the wire be positively electrified. Here the clean copper wire on becoming red-hot rapidly discharges the conductor ; when a uniform film of oxide is formed, the discharge ceases. If the containing vessel be now filled with hydrogen, and the wire again heated, a similar discharge takes place until the oxide film is completely reduced; the conductor thereafter retams its charge perfectly. : Secondly, if the conductor be negatively electrified. The Discharge of Electricity from Glowing Metals. 561 In this case, the copper wire must be heated for a longer time in air before it ceases to effect the discharge, and there is not the same sharpness of definition between the two states. The phenomena observed on heating the now oxidised wire in hydrogen differ also in this case; the hot wire not only effects discharge during the reduction of its oxide coat, but continues to possess this power certainly for a long time to the same degree. Hence, a red-hot copper wire in hydrogen exhibits the curious property of retaining pertectly a charge of negative electricity, and discharging instantly a positive electrification. The hydrogen used was fairly dry, and free from any sensible taste or smell. In dry nitrogen, the results were similar to those obtained with hydrogen. The gas was carefully dried, and passed for eight or nine hours over the copper before the electrical tests were made; the red- hot copper wire retained a negative charge, but not a positive one. The above experiments were all made in Dr. Schuster’s laboratory, and, in fact, under his immediate supervision. Dr. Schuster has suggested that they are of sufficient interest to publish in their present state, because they show more clearly than the experiments with platinum the nature of the chemical action. In the case of platinum, _ there is, of course, the advantage that the metal remains generally in the same state, but it is much lessened by the very marked and complex effects of surface condensation and occlusion. The potential of the bodies used was observed by means of an ordinary gold leaf electroscope, and was such as to cause a large divergence of the leaves. In all cases where discharge took place, it was found easy to cause complete collapse of the leaves. It is proposed to supplement this paper with ons dealing with the phenomena in pure and perfectly dry gas. OBITUARY NOTICES OF FELLOWS DECEASED. Roserr Hoyt was born at Devonport, on the 6th of September, 1807, six months after the death of his father, an officer of the Royal Navy, who, together with all the crew of his vessel, was drowned in the Grecian Archipelago. His early education; received partly in his native town, and partly at Penzance, was brief and inadequate, for when only twelve and a half years of age, he was sent to London and placed with a surgeon in practice there. His medical career appears - to have been by no means a happy one. Hesoon contrived, however, to acquire enough of Latin to qualify him for dispensing prescriptions; he gained some knowledge of anatomy by attending Brooke’s lectures; and amid the exacting labours’ of a Fleet Street dispensary he found occasional leisure hours, that enabled him to profit by the use of a good library to which he had been allowed access. For somewhere about eleven years he continued as a druggist’s assistant, until at last an illness made it needful for him to return for a season to Cornwall. About this time his grandfather’s death put him in possession of a small property on the banks of the River Fowey. With characteristic energy and enthusiasm, he was no sooner master of this source of income than he sold some of the fine old elm-trees on his ground, and with the proceeds kept himself for some months, during which he tramped all over Cornwall, looking at the scenery and the rocks, but more especially mingling with the peasantry, and gathering from their lips the legends and superstitions that still lingered in that remote western county. Long afterwards this early journey bore fruit in his volume on the ‘‘ Romances and Drolls of Devon and. Cornuwall,”’ which went through three editions. Hunt’s mind showed from his boyhood | a markedly poetic vein. While still a young man he published. by subscription at Penzance his first literary venture, which was a de- scriptive poem, entitled ““The Mount’s Bay,” followed in later life by his volume “ The Poetry of Science,” and ‘‘ Panthea, the Spirit of Nature.” He interested himself in the formation of a mechanics’ institute at Penzance, and himself gave the first of its lectures. Hunt’s first distinct entry into the domain of scientific research was suggested to him by Daguerre’s experiments in the infant art of photography. He had already gained some practical acquaintance with chemistry and chemical methods of enquiry, so that he was in some ° measure prepared to begin an independent investigation in photo- chemistry. His first paper (on “‘ Tritiodide of Mercury’’) appeared b il in the ‘Philosophical Magazine’ for 1838. From that date onward for some years he continued his enquiries, and published in the Reports of the British Association or elsewhere his results, some of which were of such practical value as materially to conduce to the advance of photography, and to entitle him to a place among the pioneers in this important practical application of science. He still farther increased his reputation by publishing his well known manual on photography, which passed through six editions, and by his ‘“ Researches on Light,” the first edition of which appeared in 1844. | In 1840 Hunt’s devotion to science and his indefatigable industry were recognised by his appointment as Secretary of the Royal Corn- wall Polytechnic Society, at Falmouth. Five years later, after he had given still further proofs of his abilities, and had attracted the notice of De la Beche, the Director-General of the Geological Survey, he was made Keeper of Mining Records, a new office then created in connexion with the Office of the Survey, at Craig’s Court. In 1851, when the School of Mines was started, in Jermyn Street, he became Lecturer on Mechanical Science, retaining at the same time his other appointment in the Mining Record Office. But after a few years he was relieved of the duties of his lecturership, that he might devote himself more uninterruptedly to the laborious duties of the collection and tabulation of the statistics of mines all over the United Kingdom. It was in these duties that he was chiefly engaged during the rest of his long and active life, until, at the age of seventy-six years, he retired on a well-merited pension. While assiduously devoted to the official work of his office, which involved him in continual correspon- dence with mining authorities and frequent journeys into the various - mining districts, Hunt yet found time, mostly in his evenings, to undertake much independent literary .work. Chief among these labours was his series of successive editions of Ure’s “ Dictionary of Arts, Manufactures, and Mines.” But he was also a constant con- tributor to literary and scientific journals. Most of his original scientific work, which was mainly in the department of photographic chemistry, was done between the years 1838 and 1853. In 1854 he was elected into this Society. He died after a brief illness on 17th October, 1887. His remarkably gentle and sympathetic nature led to his making a large circle of friends, and gave him probably a wider influence in the mining community of this country than was possessed by any other man. Ao G@. Ropert Cornewis, Lorp Naprer or Maepata, was born in Ceylon on the 6th December, 1810, and died in London on the 14th January, 1890. His father was Captain C. F. Napier, R.A. He was educated at the East India Company’s Military College at Addiscombe, and, after passing out with great credit, on the 15th December, 1826, was appointed to the Bengal Engineers. After a practical course of engineering at Chatham, he proceeded, in 1828, to India, and was soon sent to assist Captain (afterwards Colonel Sir Proby) Cautley in superintending the restored Hastern Jumna Canal, which had fallen into disuse during the decline of the Mogul Empire. In 1840, after a visit to England, he was appointed Executive Engineer at Darjiling, and, in the following year, he was transferred in the same capacity to the Karnal Division of the Public Works. Three years later he was employed in building a new station at Ambala to replace the canton- ment of Karnal. Captain Napier first saw active service in the Sutlej campaign of 1845-46. At Mudki and Ferozshah, where he was severely wounded, he was on the Staff of Sir Hugh Gough; at Sobraon he was Brigade- Major of Engineers, and at the siege of the hill fort of Kangra he was Chief Engineer. For his services in the campaign he was thanked by Government, and received the brevet of major. In 1848-49 he served in the Panjab campaign, and was present at the siege of Multan, where he was severely wounded ; the battle of Gujrat; and with Sir Walter Gilbert during the memorable pursuit of the defeated Sikh troops. In 1849 Colonei Napier was appointed ‘ Civil Engineer for the Panjab,” and whilst holding that post displayed great boldness and capacity as anengineer. Roads, such as the trunk-road from Lahore to Peshawar, were made; great rivers were bridged; old irrigation canals were reopened, and new ones, such as the Bari Doab Canal, were projected ; civil buildings were erected ; and trees were planted along the canals, or in large plantations, for fuel. In 1852-53 Colonel Napier was employed in the Black Mountain campaign against the Hassanzai tribe, and in the expedition against the Bori Afridi tribes ; and in 1857, after a visit to England, he was appointed Officiating Chief Engineer of Bengal. His services were, however, soon required on another field; throughout the operations conducted by General Havelock for the relief of Lucknow he served as Chief of the Staff to General Outram, and during the second defence of the Residency he directed the engineering operations. Though wounded at the relief of Lucknow, he was able to take part in the siege and capture of that town; and afterwards, during the campaign in Central India, he commanded a brigade, and fought the action of Jaura-Alipore. For his services during the Indian Mutiny he received the thanks of Parliament, and was made a C.B. and K.C.B. During the China war of 1860, Sir Robert Napier commanded a division under Sir Hope Grant; and at its close he received the thanks of Parliament, and was made a Major-General “ for distin- C iV guished military services.” On his return to India he was appointed to the command of a division in Bengal, and nominated a member of the Council of the Governor-General. In 1865 he was appointed Commander-in-Chief in Bombay ; and two years later he was selected to command the expedition to Abyssinia. The Abyssinian was one of the most skilfully conducted of military expeditions, and it achieved its object almost without loss. On its termination Sir Robert Napier received the thanks of Parliament; was raised to the Peerage with the title of Lord Napier of Magdala; was made a G.C.B.; and was presented by the Corporation of London with the Freedom of the City, and a sword of the value of £200. Lord Napier was afterwards Commander-in-Chief in India (1870-76) ; Governor of Gibraltar (1876-82); and Constable of the Tower (1887-90). He was made a Field Marshal in 1882, and was a G.C.S.I.; he was also an Honorary D.C.L. of Oxford, and was elected a Fellow of the Royal Society in 1869. Lord Napier never wrote anything except his official reports and despatches, and never spoke in public except upon subjects of which he was master. His speeches were always to the point, and they were listened to with attention. He was a man of perfect courage, exquisite modesty, and great simplicity of character, who was animated by a lofty conception of duty, and never, in word or deed, departed from the high ideal at which he aimed. A distinguished soldier, a sage counsellor, and a loyal servant of the Queen, he won the complete devotion and implicit confidence of the Huropean and native soldiers who served under his orders, and throughout his long life he employed his great talents in promoting the best interests of the Empire he loved so well. C. W. W. Dr. CoBBoLD was educated at Charterhouse, and matriculated at the University of Edinburgh in 1847 as a student of medicine, having previously served a three years’ apprenticeship with Mr. Crosse, of Norwich, one of the most eminent surgeons of his time. Being already possessed of great skill and dexterity in dissection and in the making of museum preparations, he became, in his second year of medical study, prosector to Professor Goodsir, and was thus led to abandon practical medicine for anatomy. He graduated in 1852, and was soon after appointed Curator of the Anatomical Museum, and began to lecture on comparative osteology in the museum. __ In 1856 Dr. Cobbold removed to London, and thereafter devoted himself chiefly to the study of animal parasites. In 1864 his well- known systematic work (‘ Entozoa: an introduction to the study of Helminthology,’ London, 1864) appeared, to which he added in 1869 a supplement containing his later researches. Vv Dr. Cobbold’s most important original contributions to Helmin- thology were his experimental researches on Tenia mediocanellata and other Cestodes, published in the work just referred to, his obser- vations on Distoma hematobium (Bilharzia hematobia, ‘ Brit. Med. Journ.,’ 1872), and those relating to the so-called Filaria sanguinis homims (F. Bancrofti) published in the Journal of the Linnean Society in 1878. Dr. Cobbold became a Fellow of the Royal Society in 1864. He lectured on Zoology at the Middlesex Hospital from 1860 to 1873, was Swiney Professor of Geology from 1868 to 1872, and subse- quently Professor of Helminthology at the Royal Veterinary College. His last communication to the Linnean Society was read on March 4, 1836, not many weeks before his lamented and unexpected death. J. B.S. JoHN Batt, Honorary Fellow of Christ’s College, Cambridge, was born in Dublin, August 20, 1818, being the son of the Right Honourable Nicholas Ball, M.P., formerly Attorney-General for Ireland, and latterly Judge of the Irish County Common Pleas. At a very early age he developed a love of both physical and biological science, which was encouraged by his father, and greatly stimulated when he was yet a child by visits to the Continent, and especially to the Alps, during which he collected assiduously, and in his first decade taught himself to measure heights barometrically. At thirteen, his family being Roman Catholic, he was sent for three years to the College of St. Mary’s, Oscote, now Stonyhurst, where he received a classical and mathematical education. This was at a time when (not as now) scientific proclivities amongst the students were repressed rather than developed, and where his principal amusement, chemistry, was (as he has himself recorded) pursued under every discouragement. It was at the meeting of the British Association at Dublin in 1835 that Ball’s scientific tastes first met recognition. After a week’s thorough enjoyment of nearly all the sections, he was placed by his father in charge of the present Professor of Botany at Cambridge (Mr. Babington), and R. M. Lingwood, in order that he might accompany these gentlemen on a scientific tour which they were about to undertake in the West of Ireland. An account of this tour appeared in the ‘Magazine of Natural History,’ vol. 9, 1836, p. 119, wherein the geological observations were supplied by young Ball. In 1836 Mr. Ball was sent to Christ’s College, Cambridge, where he devoted himself chiefly to mathematics, and in 1838 contributed a paper to the Mathematical Section of the British Association which was favourably noticed by Sir William Hamilton. At Cam- bridge he renewed his friendship with Mr. Babington, and made that c 2 v1 of the Rev. J. S. Henslow, then Professor of Botany to the University, whom he accompanied on his botanical excursions with his pupils ; and to the influence of these two botanists is to be attributed the devotion of the chief part of Ball’s scientific life to botany. In 1839 he came out twenty-seventh Wrangler in the Mathematical Tripos, but his religion debarred his receiving a degree, as it had already frustrated all hopes of a scholarship or fellowship. In 1845, after beimg called to the Irish Bar, wherein he never practised, he revisited the Alps, and undertook a series of observations on the Glaciers near Zermatt; these he never published, regarding them as only confirmatory of those previously obtained by Professor James Forbes. Mr. Ball’s next occupation was official. In 1846 he was appointed an Assistant Poor Law Commissioner for Ireland, in view of the distress caused by the ravages of the potato disease. The strain of this work on his mind and body was so great that after a year of arduous labour he was obliged to resign and seek abroad a restoration of health. After two years he returned to the office with the appointment of Second Commissioner, which he held till he entered Parliament as Member for Carlow. In 1855 he became Under Secretary for the Colonies, a post which he held for two years, proving himself a most efficient and energetic official, and one having the interests of science always at heart. Amongst other services to science may be especially mentioned the organising the Palliser Expedition, to ascertain the positions of practicable routes across the Rocky Mountains of British North America. To this expedition he had appointed as geologist and naturalist (with a staff of collectors), Dr. now Sir James Hector, F.R.S., the present Director of Geological and Meteorological Surveys in New Zealand. The principal results were the survey of four passes, including that of the “‘ Kicking Horse,” now crossed by the Canadian Pacific Railway, and the first knowledge ever obtained of the geology of the vast regions of West Canada and the Rocky Mountains. Mr. Ball also took an active part in urging upon the Colonial Governments the importance of issuing inexpensive floras of the British Colonies, which had been initiated by the late Sir W. Hooker. In 1858 Mr. Ball’s Parliamentary career ended with the expiration of the Ministry, but happily there did not depart with it his influence with future Governments; for he had meanwhile formed political friendships that lasted during his lifetime, and of which he freely availed himself on many occasions in the interests of science. In 1858 he stood for Limerick, but was defeated. In the words of an obituary notice in the ‘ Times,’ “‘‘A cloud was then rising in the horizon, which gravely disturbed the Catholic constituencies, though the rest of the world knew little of it as yet. This was the Italian Vil question. The Irish priests foresaw the coming struggle, and demanded that their candidates should take the side of the Papacy and the Duchies against Piedmont and the Revolution. This John Ball, though a good Catholic, refused to do, and he was therefore opposed by the Irish priests, and, after a hard struggle, he was defeated.” During the remainder of his life Mr. Ball devoted himself to science as an accomplished and enthusiastic amateur, untrammelled by professional duties, and with a sufficient private income to gratify his love of travel, and of both physics and botany. He was further an excellent linguist, gifted with an uncommonly retentive and accu- rate memory, an experienced mountaineer, and he had, through his connections and his early visits to the Continent, scientific friends in most of the great capitals. Though by far the greater part of his time and energies was devoted to the Alps, he made extensive journeys in Hungary, Italy, Sicily, Spain and Portugal, Morocco, Algeria, Tunis, the Canary Islands, and the United States, and a cursory visit to the West Coast of South America and Brazil, every- where collecting and observing, and forming friendships with scientific men that were kept up by an indefatigable correspondence. Of Mr. Ball’s scientific works, the most extensive were the Alpine Guides. It has been well said of them by a most competent authority that “In the history of guide books the ‘ Alpine Guide’ stands where ‘Dr. Johnson’s Dictionary’ stands amongst dictionaries.” The basis of this work is of course topographical, but the geological and botanical features of every subdivided area of the great chain of the Alps are dwelt upon with such intelligence and accuracy that no scientific man wouid regard his outfit for an Alpine tour as complete without Ball’s guides. He also wrote the greater part of the ‘Journal of a Tour in Marocco and the Great Atlas,’ being the records of an expedition made to that country in 1871, in company with Sir J. Hooker and Mr. G. Maw. ; The ‘ Spicilegium Flores Maroccanz’ is the work by which Mr. Ball will be best known to botanists. It is a virgin flora, the first ever attempted of the country, which, and especially its mountain regions, was in fact botanically as well as geographically previously un- visited ; and the materials were almost exclusively those formed by the members of the expedition. These Mr. Ball worked up with scrupulous care, and by the light of his exact knowledge of the kindred floras of Spain and the Southern Alps, with results that are beyond criticism. In a botanico-geographical point of view the unexpected conclusion was arrived at, that the Marocco flora is _ European, not sharing (as it was expected to do) in the peculiarities of the Canarian and Madeiran, thus confirming the great antiquity of the latter. Vill His other principal botanical papers are ‘“‘ On the Origin of the Flora of the Huropean Alps,’’ read before the Royal Geographical Society, and a discussion on the origin of the South American flora, published in his ‘ Notes of a Naturalist.’ Mr. Ball’s ‘Notes of a Naturalist in South America,’ is a work unique of its kind. It embraces the observations and reflections on various scientific subjects that he made, or that suggested themselves to him, during a five months’ voyage extending over 18,400 miles of ocean and embracing 100° of latitude, during which he passed only seventy days on land. The route was from England wid the West Indies to Panama, thence down the West Coast of South America to Chih, through the Straits of Magellan to the Plate river, and to Brazil, and so home. At whatever point he landed, or even touched, he was quick to secure a trip to the mountains or forests, bringing back collections and notes of value and interest; and the result is a work of which it has justly been pronounced to be worthy of a corner on the same shelf as those of Darwin, Walker, and Bates. In fact, no other narrative gives consecutively a view in accurate outline of the geographical, meteorological, and botanical features, absolute and comparative, of the different countries along the West Coast of South America from Panama to Fuegia. An appendix contains a de- scription “of the fall of temperature in ascending heights above the sea level,” and “ Remarks on Mr. Croll’s Theory of Secular Changes of the Harth’s Climate.” The botanical results are embodied in a paper read since his death before the Linnean Society of London. In meteorology, besides the appendix to the ‘ Notes of a Naturalist,’ mentioned above, he contributed papers ‘‘ On Thermometric Observa- tions in the Alps,” and “On the Determination of Heights by means of the Barometer,” to the ‘Reports of the British Association ;’ and he was the first to suggest the utilisation of the electric telegraph for meteorological purposes connected with storm warnings, in a paper ‘On Rendering the Electric Telegraph Subservient to Meteorological Research,” read before the British Association in 1848. This sugges- tion was not carried into effect till 1861. . On the subject of glaciers, he published in the Geological Society’s Journal a notice of “‘The former existence of small Glaciers in the County of Kerry,” and in the ‘ Philosophical Magazine,’ papers on the Structure of Glaciers, on the cause of their Descent, and ‘‘On the Formation of Alpine Valleys and Alpine Lakes.” Personally Mr. Ball was one of the most agreeable of men, of an affectionate nature, of warm sympathies, simple minded, and generous in thought and action. His company was much sought, from the fund of information he possessed, and the charm of his manner in communicating it. His services to science were perfectly disinterested, and his aid never withheld. His position in society was a rare one, 1X counting as he did amongst his warmest friends so many of the élite of the hterary, artistic, scientific, political, and even musical world in England and on the Continent. He was as fond of society as society was of him, and he confided to a friend his belief that to this must be laid the blame of his not having done more scientific work. He was twice married: in 1856 to an Italian lady, Eliza Parolini, daughter of a distinguished naturalist and Oriental traveller, Count Alberto Parolini, by whom he had two children (sons), who survive him, and through whom he came into estates at Bassano, in Venetia. His second wife was Miss Julia O’Beirne, daughter of F'. O’ Beirne, Esq., of Co. Leitrim, who survives him. He wasa Fellow of the Royal Irish Academy, of the Linnean, Antiquarian, and Royal Geographical Societies, and was elected a Fellow of this Society in 1868. Shortly before his death he received the Honorary Fellowship of his Cam- bridge College (Christ’s), a distinction the more appreciated as he had been debarred by his religion from University honours, which he assuredly would have otherwise won half a century earlier. For the last few years of his life Mr. Ball suffered much from an affection of the throat, which obliged him to pass the winters abroad ; and whilst in the Engadine an internal tumour was developed, for which, on his return to England in the summer of 1889, he under- went a severe operation. Under the effects of this he succumbed on October 21, 1889, at his house in South Kensington. His extensive herbarium and botanical library were left by bequest to Sir J. D. Hooker, the Director of the Royal Gardens, Kew, and the President of this Society, to be dealt with as they should think fit, with the sole object of promoting the knowledge of natural science. Jd: Da, Tue Rev. Mites Josnpa Berxe ey, M.A., F.L.S., born at Biggin Hall near Oundle, April 1, 1803, was the second son of Charles Berkeley, Hsq. and his wife, the latter a sister of P. G. Munn, the well-known water-colour artist. His family belonged to the Spetchley branch of the Berkeleys, and had for several generations been resident in Northamptonshire. From the Grammar School at Oundle, he was sent to Rugby, and in 1821 was entered at Christ’s College, Cam- bridge, where he graduated as fifth Senior Optime in 1825. He has left it on record that he became attached to natural history at a very early period, and that his scientific tendencies, both zoological and botanical, which had been fostered at Rugby, were further stimulated at Cambridge by an intimate acquaintance with the late Professor Henslow. His first clerical duty was the curacy of Thornhaugh, in Northamptonshire, where he was ordained in 1827; and in 1830 he became curate of St. John’s, Margate, from which time for upwards xe ot sixty years his labours and writings as a botanist, and especially as a mycologist, were continuous. The Mollusca were, however, the first objects of Berkeley’s study. As a boy he had made a large conchological collection, and had turned his attention to the structure and habits of the animals of British species. His earliest scientific paper was ‘‘ On new species of Modtola and Serpula,” published in the ‘ Zoological Journal,’ for 1828. It was followed by “On the internal structure of Helicolimax Lamarckit ;? “Qn Dentalium subulatum ;” ‘‘Onthe Animals of Voluta and Assiminia;” all in the same journal (1832-1834); and “On British Serpule,” and ‘“‘ Dreissena polymorpha,” in the ‘ Magazine of Natural History ’ (1834-6). At Margate Berkeley’s attention was naturally directed to the study of marine Alge, and in 1833 he brought out his ‘ Gleanings of British Alge,’ a work devoted to the more obscure and little known species. In 1836, at the request of the late Sir W. Hooker, Mr. Berkeley undertook the formidable task of systematizing the British Fungi for that author’s ‘ British Flora.’ This was a work of great research and labour, which had never before been attempted with any approach to completion. The “Systema Fungorum” of the illus- trious Swedish mycologist, Professor Fries, was adopted in it, and carried out with many additions and improvements. In 1857 appeared his ‘ Introduction to Cryptogamic Botany,’ which remained the only standard work of the kind in the English language till the publication last year of Bennett and Murray’s ‘ Handbook.’ It was followed in 1860 by his ‘ Outlines of British Fungology,’ and in 1863 by the ‘ Handbook of British Mosses.’ In 1846 Mr. Berkeley commenced his study of the potato murrain, then ravaging our crops. The result was the first complete account of its cause, the Peronospora infestans, of which he traced the life history, with the result of demonstrating that the ravages of the disease may be greatly mitigated by early planting and harvesting. In 1847 he undertook a similar investigation of the grape mildew, which he named Oidiwm Tuckert. These were followed by researches on the fungoid diseases of the wheat, cabbage, coffee, hop, pear, and onion, terminating with one on the tomato disease, which appeared in 1884, It is not too much to say that this country and our colonies are largely indebted to Mr. Berkeley’s researches and recommendations for the successful cultivation of their crops. The kindred subject of vegetable pathology next engaged Berkeley’s attention. It was virgin soil, and a series of admirable papers on the subject which appeared in the ‘Gardener’s Chronicle’ between 1854 and 1857 are the foundations of our knowledge of this most difficult and important subject. They were followed by x1 the article ‘On the Diseases of Plants’ which he contributed to the ‘ Cyclopeedia of Agriculture.’ Then a multitude of articles on kindred subjects, on botany and horticulture, appeared from time to time in the ‘Gardener’s Chronicle’ between 1840 and 1880. Unfortu- nately they are not recorded in our ‘ Catalogue of Scientific Papers;’ where, however, Berkeley is credited with upwards of a hundred articles in other periodicals, up to the year 1873, since which time twenty-one more are on record. Of Berkeley’s contributions to mycology it is impossible here even - to enumerate the more important. By himself, and in some instances in conjunction with his friend C. HK. Broome, Esq., F..8., of Batheaston, and of M. A. Curtis, for North American Fungi, he published some 6,000 species, including many new genera, from all parts of the world, arctic, antarctic, temperate, and tropical. Of these there are preserved in his own herbarium 4,886 species, that is, nearly half of the whole number that the herbarium contained. In 1879 he uncon- ditionally gave his mycological herbarium to Kew, and whether for its extent, its extraordinary richness in types of genera and species, the number of analyses made by himself with which it is enriched, or the extent to which it illustrates the life history of so many of the great pests of agriculture and horticulture, it is unquestionably unique of its kind. But unprecedented as even his contributions to systematic mycology are in importance, they are far surpassed by the fact, that he was the originator of the study in this country of the life history of fungi, and thus contributed largely to the development of our knowledge of the biological problems now known to depend for their solution on a profound study of the lowest Orders of plants. Mr. Berkeley was a man of great refinement, an excellent classical scholar, an accomplished man of letters, and an exemplary pastor. In person he was tall and portly, with a noble head, and he was singu- larly genial in manner. There is an excellent portrait of him in the rooms of the Linnean Society. As may well be supposed, he was one of the most hard working of men. For many years of his life he eked out his most scanty clerical income by keeping a school of some twenty or thirty boys, who, being boarders, left him only the very early morning for his botanical work, which was regularly commenced at 4am. His life history would not be complete without a further allusion to his spiritual duties. From Margate he was in 1838 bene- ficed to the perpetual curacy of Apethorpe and Woodnewton, North- amptonshire, the emoluments of which never exceeded £180 per annum. Meanwhile, however, his merits had attracted the notice of the late Dr. Jeune, Bishop of Peterborough,-who had said, that if ever he rose to the bench the first suitable living in his gift should be bestowed on Mr. Berkeley. This did not occur till 1868, when Xu the Bishop, true to his promise, presented him to the Vicarage of Sibbertoft, in Northamptonshire, then worth about £400, but which rapidly dwindled as agricultural distress supervened. Of private property he had none, and he himself educated his fifteen children, thirteen of whom lived to be over twenty-one years of age. His works, it need hardly be said, yielded the merest trifle, but he was fortunate in holding examinerships in the University of London, Cambridge, and the Society of Apothecaries ; he was also for several years botanical referee to the Royal Horti- cultural Society. In 1863 he received one of the Royal Medals of the Royal Society for his researches on the reproductive organs in Thallogens, &c.; and in 1879 a Civil Service Pension of £100 per annum was awarded him for his investigations on the diseases of agricultural crops, &c. He was elected a Fellow of the Linnean Society in 1836, and of this Society in 1879. Shortly before his death, which took place at Sibbertoft, on July 30th, 1889, he was made an Honorary Fellow of his Cambridge College (Christ’s). He married in 1833 Miss Cecilia Hmma Campbell, by whom he had, as stated above, fifteen children, ten of whom survive him. aD. A. Str Rosert JonHn Kane, LL.D., F.R.S., who died in Dublin on the 16th of February, 1890, in his eighty-first year, belonged to the distinguished group of chemists whose chief scientific work was accomplished during the first half of the present century. Sir R. Kane’s contributions to chemical science almost ceased after 1850, when his official relations with the Irish Government drew off his attention to the economic and educational problems of the time. His scientific knowledge, scholarly attainments, and experience were then freely utilised by the State in the efforts made to establish the system of education which was, until very recently, represented by the Queen’s University and its Colleges at Cork, Belfast, and Galway. Born in 1809 at Dublin, where his father had established a chemi- cal factory, young Kane was educated in his native city, and ulti- mately (in 1835) graduated in Arts at the University, whose LL.D. degree was subsequently conferred upon him (Stip. condonatis). The family connexion with industrial chemistry seems to have early attracted him to scientific pursuits, and the first results of his chemical work appeared in 1829, in the form of two short papers on Native Compounds of Manganese, including the description of an arsenide of manganese, since known as ‘‘ Kaneite.” But before the publication of these papers Kane had commenced the study of medi- cine, apparently with a view to adopt it as a profession, for he became clinical clerk to Graves and Stokes at the then celebrated Meath Hospital, in Dublin, and went to Paris in 1830 to continue his medi- xl eal work. Here, however, he attended Chevreul’s lectures, and became acquainted with the brilliant Dumas, whose enthusiasm seems to have revived the young Irishman’s love for chemistry, and decided his choice of a scientific rather than a medical career. _ Shortly after returning to Dublin, in 1831, Kane obtained ce Lecturership in Chemistry at the medical school then maintained by the Apothecaries’ Company of Ireland, and this office he held until 1843. Most of his time was now devoted to scientific teaching and investigation, while a portion was occupied in completing his studies in Medicine and Arts. Although he never practised as a physician, he obtained the licence of the Dublin College of Physicians in 1835, and was elected to the Fellowship of that body in 1843. When fairly established in professorial work Kane commenced the examination of some compounds of the metal platinum, and pub- lished accounts of the stannous chloroplatinite, of a substance which he regarded as platinoso-platinic iodide, Pt,I,, and of other bodies, in the ‘Dublin Journal of Medical and Chemical Science.’ But his work on the salts of some of the complex platinum bases derived from ammonia only appeared at the end of a paper in the ‘ Philoso- phical Transactions’ for 1842, entitled ‘‘ Contributions to the Chemi- cal History of Palladium and Platinum.” This paper was chiefly concerned with the compounds of palladium, of which he described a suboxide and a corresponding chloride, Pd,0l,; while the action of alkalies on palladious chloride, PdCl,, afforded several basic sub- stances which he regarded as definite compounds. In the course of the same investigation Kane produced a number of interesting bodies by the action of ammonia on the salts of palladium, which doubtless included derivatives of the bases palladamine and paliadiamine, sub- sequently recognised by Dr. Hugo Miller in his fine investigation of similar interactions. . During the “thirties”? much progress was made in evolving order out of the apparently chaotic masses of organic compounds. Early in the decade Dumas had propounded his ephemeral “ etherine ” theory of ordinary alcohol and its derivatives; Liebig and Wohler had been led to recognise the existence of compound radicals; and, later on, the laws of substitution were made out by Dumas, wnt the theory of types was proposed. Kane’s acquaintance with Dumas and association with Liebig—in whose laboratory he sometimes worked during the summer months—led him to take an active part in the discussions of the time, and to propose the theory of the nature of common ether and alcohol which now prevails—namely, that they include the radical ethyl, C,H;. It is true that Berzelius arrived at the same conclusion about the same time, and worked out the ‘subject with his usual thoroughness; but Kane claimed to be the independent discoverer of what was then termed the “ Ethyl Theory.” Xiv _ The inquiries being pursued, at the period of which we write, with regard to compounds of the alcoholic class, led Kane to re-examine pyroxylic, or wood, spirit, which had already been investigated by Dumas and by Liebig, though these chemists had obtained somewhat discordant results. Liebig’s products were shown by Kane to be im- pure, as the alcohol used seemed to contain some methylal, ethylene dimethylate, and other bodies. Kane then succeeded in arranging the process for separating nearly pure methyl alcohol from wood spirit with which his name is now generally connected. The success of his method depends on a fact which he had observed, namely, that methyl alcohol forms a definite and crystallisable compound with calcium chloride which is not decomposed at 100° C. in absence of water; hence dehydrated wood spirit, when saturated with anhydrous calcium chloride, can have nearly all its volatile impurities distilled off, leaving the calcium chloride compound with methyl alcohol; the latter, if then mixed with water, is decomposed, so that a second dis- tillation affords nearly pure methyl alcohol which only needs dehydra- tion. From the alcohol so obtained Kane prepared and described several salts of methyl-sulphuric acid. Among the volatile compounds mentioned above as bye- products from the purification of methyl alcohol was the liquid now termed acetone, but then, generally, ‘‘ pyroacetic spirit.” At the time (1836-7) acetone was known to consist of C,H,O,* but the nature of the com- pound was undetermined; and this problem Kane sought to solve. The results of his investigation led him to conclude that acetone is a hydrate analogous to ethyl alcohol, but containing a radical which he named “ mesityl”” = C,H,. A number of derivatives were prepared by Kane from the impure “‘ pyroacetic spirit’ he worked with, which seemed to support his view of the nature of acetone. Thus he obtained an oxide which he named “ mesityl oxide,’+ because it was apparently related in composition to acetone as ethyl oxide is to ethyl aicohol ; again, by dehydrating acetone a hydrocarbide resulted whose empirical formula proved to be C,H,;f this he named “ mesitylene,” as in composition and mode of generation it seemed to arise from mesityl alcohol (acetone) as ethylene, C,H,, does from ethyl alcohol. Later on, as new facts were discovered about acetone, it became evident that the alcoholic hypothesis was not consistent with them, for the compound was found to possess aldehydic rather than alco- holic characters. According to the newer view acetone was acetyl * C,H,O, according to the atomic weights for carbon and oxygen then used. + Later on Kane discovered a liquid product of the action of heat on acetone, which he named “‘ Dumasine.” This has since been proved by Fittig to be isomeric with mesityl oxide. t{ Hofmann has shown that this important body, which Kane discovered, has the molecular formula CyH,, (=3C3H4), and is symmetrical trimethylbenzene. xV methide, ordinary aldehyde being acetyl hydride; this received powerful support from Williamson’s study of the genesis of acetone and its homologues by heating barium salts of the fatty acids; while Freund’s synthesis of acetone by means of zine ethide and acetyl chloride, together with the work of Boutlerow, Friedel, and Crafts, involved a further modification, so that acetone and its homologues are now simply regarded as compounds of carbonyl with two alcohol radicals. Thus the difficult problem undertaken by Kane more than half a century ago, when very vague notions prevailed as to the constitution of some of our most common carbon compounds, required the more powerful methods of modern chemistry for its complete solution. ; The derivatives of ammonia early attracted Professor Kane’s atten- tion, as his friend Dumas had shown in 1820 that oxamide, C,0,(NH,),, included the ammonia residue NH,, which he termed amide; and that many substances existed which might be supposed to contain the same group. Kane, starting with this general idea, commenced the examination of a number of inorganic compounds which might contain the group NH,. The most interesting of these isthe ‘“ white precipitate of mercury,” which had long been known, and about whose composition conflicting statements were made. Kane studied the formation of that body with great care, and showed that a definite compound free from oxygen could be obtained under proper conditions, whose composition is represented by the formula HgNH,Cl. He was led by his work on this substance, and on similar compounds of other metals, to conclude that the three atoms of hydrogen in ammo- nia, NH3, are not removed with equal readiness in chemical exchange, and that ammonia is, in fact, the hydride of a persistent group, NHg, which he termed amidogene. Kane’s amidogene theory, and its consequences as affecting the view taken of the constitution of ammoniacal salts, attracted great inte- rest at the time. That Berzelius attached much importance to Kane’s work is evident from the remark attributed to him in Wohler’s ‘ Jahresbericht’ for 1838, ‘‘ Diese Untersuchungen von Kane gehéren meiner Ansicht nach zu den wichtigeren des verflossenen Jahres.” Although subsequent investigations of Wurtz, Hofmann, and many others have shown that the three atoms of hydrogen in ammonia can be successively replaced by methyl or ethyl without affording the metameric mono- or di-substituted derivatives which might be expected to exist on the amidogene theory, it is interesting to note that Curtius, working nearly fifty years after Kane’s papers were pub- lished, has succeeded in obtaining the hydrate of diamidogene, NH,—NH,, or as it is now termed hydrazine. Kane was awarded the Cunningham Medal of the Royal Irish Academy in 1843 for his researches on the above subject. XV1 In 1841 Kane recived the Royal Medal of this Society for his work published in the ‘ Philosophical Transactions’ for 1840 on the chemical history of the well-known substances archil and litmus, which are colouring matters obtained from various lichens of the Rocella, Vartolarta, and other genera. When the lichens are allowed to ferment in presence of ammoniacail salts, they soon afford the magnificent purple-red colouring matter termed orceine. But if carbonates of the alkalies are present during the process of fermenta- tion, blue litmus results. The two colouring matters were previously examined by Robiquet, Heeren, and Dumas, yet Kane carried the investigation much further, and not only improved the methods of separating some of the substances present in the impure pigments, but endeavoured to trace them to proximate constituents of certain of the lichens. In the course of this laborious investigation he obtained a number of new substances which he regarded as definite compounds. The general result of the inquiry was that the red ‘“orceine” of archil, and the blue substance of litmus, named by Kane ‘azolitmin,” differ only by one atom of oxygen, the blue coloured body containing most oxygen; and that both colouring matters are products of the action of ammonia and atmospheric air, in presence of a ferment, on orcin already free in the lichens or | resulting from the hydrolysis of some of their constituents. In 1842 Kane published an account of his examination of the colouring matter of the berries of [thamnus tinctoria, one of the buckthorns, which were imported in considerable quantities from the Levant for dyeing, under the name of “ Persian berries.” From these when in the unripe state he isolated a golden-yellow colouring matter, which he named chrysorhamnine, and from the ripe berries, olive-yellow sxanthorhammine, and showed that the latter results from the action of oxygen and the elements of water on chryso- rhamnine. Plant products.always seemed to have a great attraction for Kane, and amongst others the volatile oils, with which he worked much from time to time, though he published little about them, as he found greater difficulty than he anticipated in arriving at a “ law connecting the composition of the secretions of plants of the same genus or natural family.” But he made some useful contributions to our knowledge of these oils, as well as to that of other minor subjects, which the limits of this notice do not permit us to specify in detail. In 1843 Kane was appointed Professor of Natural Philosophy to the Royal Dublin Society, and during the following year published his ‘Hlements of Chemistry,’ a work which well represented the general theories and the practice of the science at the time. But his connexion with the Royal Dublin Society—a body which has always been foremost in seeking to develop agriculture and industry in XVi1 Ireland—gave a new direction to his energies. He commenced a protracted investigation of the “ relations of the country to the prime materials of the chemical and metallic manufactures,” and was led much beyond the original limits of his inauiry ‘‘to discuss several important statistical and moral problems affecting the industrial pro- gress of Ireland.” The first part of the investigation involved a large amount of analytical work on native ores and raw materials, and the results were embodied in a course of lectures delivered before the Royal Dublin Society. In these lectures it was also pointed out that foreign Governments fostered native industries with anxious care, and that Continental nations were in consequence making giant strides in manufacturing activity, while our own Government did little or nothing to develop the resources of the country. These lectures were published in 1844, and excited such interest that ‘The Industrial Resources of Ireland’ quickly reached a second edition, and the Government of the day shortly after made one step forward in the direction indicated by Kane in establishing a ‘‘ Museum of Irish Industry,” at St. Stephen’s Green, of which he was made the first Director. In this office he devoted much time to the develop- ment of the museum under his control, and especially to the esta- blishment of evening lectures, and practical instruction for artizans - and others who could not attend day classes. This excellent technical scientific school proved a most important adjunct to the mnseum, and supplied a definite want; it continued its valuable, if humble, work until converted into the “ Royal College of Science for Ireland.” The honour of knighthood was conferred on the subject of this memoir in 1846, and in 1849 Sir Robert Kane was elected to the Fellowship of the Royal Society. In the latter year Sir Robert’s official connexion with the Museum of Irish Industry almost ceased, as he went to Cork in the capacity of President of the Queen’s College, then recently established in that city. The duties of that important office he zealously performed until 1873, when he resigned, and returned to Dublin, where he afterwards lived in comparative retire- ~ment. Although Sir Robert Kane’s official engagements prevented the pursuit of his old work, he continued his connexion with the ‘ Philo- sophical Magazine,’ one of whose Editors he was from 1840. After his return to Dublin, in 1873, Sir Robert became a Commissioner of National Education; he also took much interest in the work of the various societies of the Irish metropolis. He was for some years President of the Royal Geological Society of Lreland, and from 1877 to 1882 of the Royal Irish Academy; he occupied a seat on the Academie Council of Dublin University, and on the Senate of the Royal University. In the various public positions which Sir Robert Kane filled during a long and distinguished career, his natural XVill courtesy and diplomatic skill enabled him to disarm much opposition to reforms which his mature judgment and statesmanlike grasp of affairs led him to suggest. Notwithstanding advanced years, Sir Robert Kane’s health was generally good, but the end came after a very short illness, and one morning last February many gathered at his funeral to honour the memory of one whose scientific reputation belonged to a past genera- tion, and whose later life was largely devoted to the advancement of his country’s material interests. J. H. R, INDEX to ABNEY (W. de W.) and G. S. Edwards, on the effect of the spec- trum on the haloid salts of silver, 22, 249. Acton (EF. H.) the assimilation of carbon by green plants from certain organic compounds, 150. Alloys of nickel and iron, magnetic pro- perties of (Hopkinson), 23. the liquation of gold and platinum (Matthey), 180. Apteryx, observations on the anatomy and development of (Parker), 454. Atomic weight, the relation of physio- logical action to (Johnstone and Carnelley), 21. Aurore and comets, comparison of the _ spectra of nebule and stars of groups I and II with those of (Lockyer), 28. Bakerian lecture (Schuster), 300, 526. Ball, John, obituary notice of, v. Basset (A. B.) on the extension and fiexure of cylindrical and spherical thin elastic shells, 45. Beevor (C. E.) and V. Horsley, an ex- perimental investigation into the ar- rangement of the excitable fibres of the internal capsule of the bonnet monkey (Macacus sinicus), 21. Berkeley, Rev. Miles Joseph, obituary notice of, ix. Bidwell (S.) on the effect of tension upon magnetic changes of length in wires of iron, nickel, and cobalt, 469. Bile, observations on the secretion of, in a case of biliary fistula (Robson), 499. observations regarding the excre- tion and uses of (Robson), 129. ~ Bonnet monkey (Macacus sinicus), an experimental investigation into the arrangement of the excitable fibres of the internal capsule of the (Beevor and Horsley), 21. Boys (C. V.) on the heat of the moon * and stars, 480. Brain of Clupea harengus, some stages VOL. XLVII. in the development of the (Holt), 199. British Isles, preliminary note on sup- plementary magnetic surveys of special districts in the (Riicker and Thorpe), 443. the variability of the tempe- rature of the, 1869-1883 inclusive (Scott), 303. Bryan (G. H.) on the stability of a rotating spheroid of perfect liquid, 367. Calorimeter, on the steam (Joly), 45, 218. Camphor, measurements of the amount of oil necessary in order to check the motions of, upon water (Rayleigh), 364. Camphoric acids, researches on the chemistry of the (Marsh), 6. Candidates for election, list of, 276. Cannizzaro (Stanislao) elected, 1. Carbon, the assimilation of, by green plants from certain organic com- pounds (Acton), 150. Carbon flutings in the spectra of celestial bodies, the presence of bright (Lock- yer), 39. Carnelley (T.) and H. J. Johnstone, the relation of physiological action to atomic weight, 21. — Carus-Wilson (C. A.) the rupture of steel by longitudinal stress, 363. Castor-oil plant (Ricinus communis), on the germination of the seed of the (Green), 146. Cervical ganglion, on the progressive paralysis of the different classes of nerve-cells in the superior (Langley and Dickinson), 379. Chauveau (Auguste) elected, 1. Chree (C.) on the effects of pressure on the magnetisation of cobalt, 41. Christie (W. H. M.) elected a member of council, 142. Ciliary or motor oculi ganglion, on the development of the (Ewart), 287. Clupea harengus, some stages in the development of the brain of (Holt), 199. d XX Coal-measures, on the organisation of the fossil plants of the. Part XVII (Williamson), 294. Cobalt, on the effects of pressure on the magnetisation of (Chree), 41. Cobalt, nickel, and iron, on the effect of tension upon magnetic changes ot length in wires of (Bidwell), 469. the internal friction of, studied by means of magnetic cycles of very minute range (Tomlinson), 13. Cobbold (Dr.) obituary notice of, iv. Colour-blindness and colour-perception, a new theory of (Edridge-Green),176. Comets and aurore, comparison of the spectra of nebule and stars of groups I and II with those of (Lockyer), 28. Conroy (Sir J.) some observations on the amount of luminous and non-lumin- ous radiation emitted by a gas flame, 41,55. * Council, ballot for a member of, 137, 142. Crangon vulgaris, the variations occur- ring in (Weldon), 445. Cranial nerves of the torpedo, the. Pre- liminary note (Ewart), 290. Croonian lecture (Ward), 213, 393. Crustacea, the variations occurring in certain decapod.—I. Crangon vul- garis (Weldon), 445. Cyanogen reaction of proteids, a (Gnezda), 202. Cylindrical and spherical thin elastic shells, on the extension and flexure of (Basset), 45. Cystin, on a fermentation causing the separation of. Preliminary commu- nication (Delépine), 198. Delépine (8.) on a fermentation causing the separation of cystin. Preliminary communication, 198. Dickinson (W. L.) and J. N. Langley, on the progressive paralysis of the different classes of nerve cells in the superior cervical ganglion, 379. Digestions, a comparative study of natural and artificial. Preliminary account (Lea), 192. Downing (Capt.) notes on some peculiar relations which appear in the great pyramid from the precise measure- ments of Mr. Flinders Petrie, 459. Edridge-Green (F. W.) a new theory of colour-blindness and colour-percep- tion, 176. Edwards (G. 8.) and W. de W. Abney, on the effect of the spectrum on the haloid salts of silver, 22, 249. ! INDEX. | Electrie discharge between electrodes at different temperatures in air and in high vacua, on (Fleming), 118. Electricity, a determination of “vv,” the ratio of the electromagnetic unit of, to the electrostatic unit (Thomson and Searle), 376. the discharge of, from glowing metals (Stanton), 559. through gases. Preliminary communication, — Bakerian lecture (Schuster), 300, 526. Equations, memoir on the symmetrical functions of the roots of systems of (MacMahon), 176. Ewart (J. C.) on the development of the ciliary or motor oculi ganglion, 287. the cranial nerves of the torpedo. Preliminary note, 290. Ferment, the nitrifying process and its specific (Frankland and Frankland), 296. Fermentation causing the separation of cystin, on a. Preliminary communi- cation (Delépine), 198. Fistula, observations on the seeretion of bile in a case of biliary (Robson), 499. Fixation of free nitrogen, new experi- ments on the question of the. Pre- liminary notice (Lawes and Gilbert), 85 Fleming (J. A.) on electrie discharge between electrodes at different tem- peratures in air and in high vacua, 118. Foreign members elected, 1.. Fossil plants of the coal-measures, or the organisation of the. Part XVII (Williamson), 294, . Frankland (P. F.) and G. C. Frank- land, the nitrifying process and its specific ferment, 296. Free stream lines, (Michell), 129. Friction, internal, of iron, nickel, and cobalt, studied by means or magnetic cycles of very minute range (Tomlin- son), 13. the theory of Ganglion, on the development of the ciliary or motor oculi (Ewart), 287. ——. on the progressive paralysis of the different classes of nerve cells in the superior cervical (Langley and Dick- inson), 379. - Gas flame, some observations on the amount of luminous and non-lumin- ous radiation emitted by a (Conroy), 41, 55. | iii pala : INDEX. Germination of the seed of the castor- oil plant (Ricinus communis), on the (Green), 146. Gilbert (J. H.) and Sir J. B. Lawes, new experiments on the question of the fixation of free nitrogen. Pre- liminary notice, 85. Gnezda (J.) a cyanogen reaction of proteids, 202. Gold and platinum alloys, the liquation of (Matthey), 180. Green (F. W. EH.) See Edridge-Green. Green (J. R.) on the germination of the seed of the castor-oil plant (Recinus — communis), 146. Haloid salts of silver, on the effect of the spectrum on the (Abney and Edwards), 22, 249. Harcourt (L. F. V.) Harcourt. Heat of the moon and stars, on the (Boys), 480. Holt (HE. W. L.) some stages in the development of the brain of Clupea harengus, 199. Hopkinson (J.) magnetic properties of alloys of nickel and iron, 28. physical properties of nickel steel, 8 See Vernon- Horsley (V.) and Cs E. Beevor, an ex- perimental investigation into the ar- rangement of the excitable fibres of the internal capsule of the bonnet monkey (Macacus sinicus), 21. Host and parasite, the relations between, in certain epidemic diseases of plants, —Croonian lecture (Ward), 213, 393. Hughes (T. McKenny) admitted, 1. Hunt (Robert) obituary notice of, 1. Internal capsule of the bonnet monkey, an experimental investigation into the arrangement of the excitable fibres of the (Beevor and Horsley), 21. Iron and nickel, magnetic properties of alloys of (Hopkinson), 23. Tron, nickel, and cobalt, on the effect of tension upon magnetic changes of _ length in wires of (Bidwell), 469. the internal friction of, studied by means of magnetic cycles of very minute range (Tomlinson), 13. Johnstone (H. J.) and T. Carnelley, the relation of physiological action to atomic weight, 21. Joly (J.) observations on the spark dis- charge, 67. on the steam calorimeter, 45, 218. XX1 Kane (Sir Robert John) obituary notice of, xii. Langley (J. N.) and W. L. Dickinson, on the progressive paralysis of the different classes of nerve cells in the superior cervical ganglion, 379. Lawes (Sir J. B.) and J. H. Gilbert, new experiments on the question of the fixation of free nitrogen. Pre- liminary notice, 85. Lea (A. 8S.) A comparative study of natural and artificial digestions. Pre- liminary account, 192. Light, remarks on Mr. A. W. Ward’s paper on the magnetic rotation of the plane of polarisation of, in doubly refracting bodies (Wiener and Wed- ding), 1. Liquation of gold and platinum alloys, the (Matthey), 180. Liquid, on the stability of a rotating spheroid of perfect (Bryan), 367. Liquid surfaces, on the tension of recently formed (Rayleigh), 281. Lockyer (J. N.) comparison of the spectra of nebule and stars of groups I and ITI with those of comets and aurore, 28. note on the spectrum of the nebula of Orion, 189. on the chief line in the spectrum of the nebule, 129. preliminary note on photographs of the spectrum of the nebula in Orion, 189. the presence of bright carbon flutings in the spectra of celestial bodies, 39. Macacus sinicus, an experimental inves- tigation into the arrangement of the excitable fibres of the internal capsule of the bonnet monkey (Beevor and Horsley), 21. MacMahon (P. A.) memoir on the symmetrical functions of the roots of systems of equations, 176. Magnetic changes of length in wires of iron, nickel, and cobalt, on the effect of tension upon the (Bidwell), 469. induction (Tomlinson), 18. properties of alloys of nickel and iron (Hopkinson), 28. rotation of the plane of polari- sation of light in doubly refract- ing bodies, remarks on Mr. A. W. Ward’s paper on the (Wiener and Wedding), 1. surveys of special districts in the British Isles, preliminary note on d 2 Xk supplementary (Riicker and Thorpe), 443. Magnetisation of cobalt, on the effects of pressure on the (Chree), 41. Mallet (J. W.) on a second case of the occurrence of silver in volcanic dust, namely, in that thrown out in the eruption of Tunguragua, in the Andes of Ecuador, January 11th, 1886, 277. Mammalian spinal cord, on outlying nerve-cells in the (Sherrington), 144. Marsh (J. E.) researches on the chemistry of the camphorie acids, 6. Matthey (H.) the liquation of gold and platinum alloys, 180. Mersey, investigations into the effects of training walls in an estuary like the (Vernon-Harcourt), 142. Metals, the discharge of electricity from glowing (Stanton), 559. Michell (J. H.) the theory of free stream lines, 129. Milk dentition in (Thomas), 126, 246. Moon and stars, on the heat of the (Boys), 480. Orycteropus, a Napier of Magdala, Lord, notice of, ii. Nebula in Orion, preliminary note on photographs of the spectrum of the (Lockyer), 189. —— of Orion, note on the spectrum of the (Lockyer), 189. Nebule, on the chief line in the spec- trum of the (Lockyer), 129. and stars of groups I and II, comparison of the spectra of, with those of comets and aurorze (Lockyer), 28. Nerve-cells, on the progressive paralysis of the different classes of, in the supe- rior cervical ganglion (Langley and Dickinson), 379. in the mammalian spinal cord, on outlying (Sherrington), 144. Nickel and iron, magnetic properties of alloys of (Hopkinson), 23. Nickel, cobalt, and iron, on the effect: of tension upon magnetic changes of length in wires of (Bidwell), 469. the internal friction of, studied by means of magnetic cycles of very minute range (Tomlinson), 13. Nickel steel, physical properties of (Hopkinson), 138. Nitrifying process and its specific fer- ment, the (Frankland and Frankland), 296. Nitrogen, obituary new experiments on the INDEX. question of the fixation of free. Pre- liminary notice (Lawes and Gilbert), 85. Obituary notices :— Ball, John, v. Berkeley, Rev. Miles Joseph, ix. Cobbold, Dr., iv. Hunt, Robert, i. Kane, Sir Robert John, xii. Napier of Magdala, Lord, ii. Oil, measurements of the amount of,. necessary in order to check the motions of camphor upon water (Rayleigh), 364. Organic compounds, the assimilation of carbon by green plants from certain (Acton), 150. Orion, note on the spectrum of the nebula of (Lockyer), 189. --— preliminary note on photographs of the spectrum of the nebula in (Lockyer), 189. Orycteropus, a milk (Thomas), 126, 246. dentition in Paralysis of the different classes of nerve- cells in the superior cervical ganglion, on the progressive (Langley and Dickinson), 379. Parker (T. J.) observations on the ana- tomy and development of Apteryz, 454. Photographie method for determining variability in stars, on a (Roberts), 137. Photographs of the spectrum of the nebula in Orion, preliminary note on (Lockyer), 189. Photometer, 2 compound wedge (Spitta), 15. Physical properties of matter, the in- fluence of stress and strain on the. Part III. Magnetic induction (con- tinued) (Tomlinson), 13. Physiological action, the relation of, to atomic weight (Johnstone and Car- nelley), 21. Plants, assimilation of carbon by green, from certain organic compounds (Acton), 150. fossil, of the oodles on the organisation of the. Part XVII (Wil- liamson), 294. the relations between host and parasite in certain epidemic diseases of,—Croonian lecture (Ward), 213, 393. Platinum and gold alloys, the liquation of (Matthey), 180. Pneumatic analogue of the Wheatstone bridge, on a (Shaw), 462. INDEX. Polarisation of light, remarks on Mr. A. W. Ward’s paper on the magnetic rotation of the plane of, in doubly refracting bodies (Wiener and Wed- ding), 1. Presents, list of, 18, 25, 49, 126, 133, 140, 148, 178, 189, 210, 216, 292, 298, 300, 390, 459, 524. Proteids, a cyanogen (Gnezda), 202. Pyramid, notes on some peculiar rela- tions which appear in the great, from the precise measurements of Mr. Flinders Petrie (Downing), 459. reaction of Radiation emitted by a gas flame, some observations on the amount of luminous and non-luminous (Con- roy), 41, 55. Rayleigh (Lord) measurements of the amount of oil necessary in order to check the motions of camphor upon water, 364. —- on the tension of recently formed liquid surfaces, 281. Reinold (A. W.) and A. W. Ricker, on black soap films, 303. Ricinus communis, on the germination of the seed of the castor-oil plant (Green), 146. Roberts (I.) on a photographic method for determining variability in stars, 137. Robson (A. W. M.) observations on the secretion of bile in a case of biliary fistula, 499. observations regarding the excre- tion and uses of bile, 129. Rotating spheroid of perfect liquid, on the stability of a (Bryan), 367. Rowland (Henry A.) elected, 1. Riicker (A. W.) and A. W. Reinold, on black soap films, 303. and T. E. Thorpe, preliminary note on supplementary magnetic surveys of special districts in the British Isles, 443. Scale, on the unit of length of a stand- ard, by Sir George Shuckburgh, apper- taining to the Royal Society (Walker), 186. Schuster (A.) the discharge of electricity through gases. Preliminary commu- nication,—Bakerian lecture, 300, 526. Scott (R. H.) the variability of the tem- perature of the British Isles, 1869- 1883, inclusive, 303. Searle (G. F. C.) and J. J. Thomson, a determination of “vv,” the ratio of the electromagnetic unit of electricity to the electrostatic unit, 376. XXIll Shaw (W. N.) on a pneumatic analogue of the Wheatstone bridge, 462. Shells, on the extension and flexure of cylindrical and spherical thin elastic (Basset), 45. Sherrington (C. 8.) on outlying nerve- cells in the mammalian spinal cord, 144. Shuckburgh (Sir George) on the unit of length of a standard scale by, apper- taining to the Royal Society (Walker), 186. Silver, effect of the spectrum on the haloid salts of (Abney and Edwards), 22, 249. Silver in volcanic dust, on a second case of the occurrence of, namely, in that thrown out in the eruption of Tungu- ragua, in the Andes of Ecuador, January 11th, 1886 (Mallet), 277. Soap films, on black (Reinold and Ricker), 303. Spark discharge, observations on the (Joly), 67. : Spectra of celestial bodies, the presence of bright carbon flutings in the (Lockyer), 39. of nebule and stars of groups I and II, comparison of the, with those of comets and aurore (Lockyer), 28. Spectrum, on the effect of the, on the haloid salts of silver (Abney and Edwards), 22, 249. of the nebula in Orion, preliminary note on photographs of the (Lockyer), 189. of the nebula of Orion, note on the (Lockyer), 189. of the nebule, on the chief line in the (Lockyer), 129. Spheroid of perfect liquid, on the sta- bility of a rotating (Bryan), 367. Spinal cord, on outlying nerve-cells in the mammalian (Sherrington), 144. Spitta (H. J.) a compound wedge photo- meter, 15. Stanton (A.) the discharge of electricity from glowing metals, 559. Stars, on a photographic method for determining variability in (Roberts), 137. on the heat of the moon and (Boys), 480. and nebule of groups I and IT, comparison of the spectra of, with - those of comets and aurorse (Lockyer), 28. Steam calorimeter, on the (Joly), 45, 218. Steel, the rupture of, by longitudinal stress (Carus- Wilson), 363. XXIV Stream Jines, the theory of free (Michell), 129. Stress, the rupture of steel by longi- tudinal (Carus- Wilson), 363. Stress and strain, the influence of, on the physical properties of matter. Part [II. Magnetic induction (eon- tinued) (Tomlinson), 13. Symmetrical functions of the roots of systems of equations, memoir on the (MacMahon), 176. Temperature of the British Isles, 1869- 1883, inclusive, the variability of the (Scott), 303. Tension, on the effect of, upon mag- netic changes of length in wires of iron, nickel, and cobalt (Bidwell), 469. - of recently formed liquid surfaces, on the (Rayleigh), 281. Thomas (O.) a milk dentition in Oryeter- opus, 126, 246. Thomson (J. J.) and G. F. C. Searle, a determination of “v,’ the ratio of the electromagnetic unit of electricity to the electrostatic unit, 376. ~ Thorpe (T. E.) and A. W. Riicker, pre- liminary note on supplementary mag- netic surveys of special districts in the British Tsles, 443. Tomlinson (H.) the influence of stress and strain on the physical properties of matter. Part lIl. Magneticinduc- | tion (continued). The internal fric- | tion of iron, nickel, and cobalt, studied | by means of magnetic cycles of very minute range, 13. Torpedo, the cranial nerves of the. Pre- liminary note (Ewart), 290. : Training walls, investigations into the effects of, in an estuary like the Mer- sey (Vernon-Harcourt), 142. Tunguragua, in the Andes of Ecuador, January 11th, 1886, on a second case ‘of the occurrence of silver in volcanic dust, namely, in that thrown out in the eruption of (Mallet), 277. Unit of length of a standard scale by Sir George Shuckburgh, appertaining to the Royal Society, on the (Walker), 186. END OF FORTY-SEVENTH “V,” a determination of, the ratio of the electromagnetic unit of electricity to the electrostatic unit (Thomson and Searle), 376. Variability in stars, on a photographic method for determining (Roberts), 137. Variations occurring in certain decapod crustacea. I. Crangon vulgaris (Weldon), 445. Vernon-Harcourt (L. F.) investigations into the effects of training walls in an estuary like the Mersey, 142. Vice-Presidents, appointment of, 1. Volcanic dust, on a second case of the occurrence of silver in, namely, in that thrown out in the eruption of Tunguragua, in the Andes of Ecuador, January 11th, 1886 (Mallet), 277. Walker (J. T.) on the unit of length of a standard scale by Sir George Shuck- burgh, appertaining to the Royal Society, 186. Ward (H. M.) the relations between host and parasite in certain epidemic diseases of plants,—Croonian lecture, 213, 393. Ward’s (A. W.) paper on the magnetic rotation of the plane of polarisation of light in doubly refracting bodies, remarks on (Wiener and Wedding), 1. Wedding (W.) and O. Wiener, remarks on Mr. A. W. Ward’s paper ‘on the magnetic rotation of the plane of polarisation of light in doubly refract- ing bodies,’ 1. Wedge photometer, acompound (Spitta), 15 Weldon (W. F. R.) the variations occurring in certain decapod crustacea. I. Crangon vulgaris, 445. Wheatstone bridge, on a pneumatic analogue of the (Shaw), 462. Wiener (O.) and W. Wedding, re- marks on Mr. A. W. Ward’s paper ‘on the magnetic rotation of the plane of polarisation of light in doubly refracting bodies,’ 1. Williamson (W. C.) on the organisation of the fossil plants of the coal- measures. Part XVII, 294. Wilson (C. A.C.). See Carus- Wilson. VOLUME. HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN’S LANE, *, PROCEEDINGS OF \ MAR 5 180 Ni) eye ROYAL SOCIETY. VOL. XLVII. the Plane of CONTENTS. December 5, 1889. PAGE I. Remarks on Mr. A. W. Ward’s Paper ‘“ On the Magnetic Rotation of Polarisation of Light in doubly refracting Bodies.’ By O. WIENER and W. Wepp1nG, Physikalisches Institut, Strassburg i. B. II. Researches on the Chemistry of the Camphoric Acids. By J. HE. Marsu, B.A., Demonstrator of Organic Chemistry at the University mi Oxford ‘ III. The Influence of Stress and Strain on the Physical Properties of Matter. Part III. Magnetic Induction (continued). The Internal Friction of Tron, Nickel, minute Range. and Cobalt, studied by means of Magnetic Cycles of very By Herserr Tomiinson, B.A., F.R.S. IV. A Compound Wedge Photometer. By E. J. Sprrra, L.R.C. Phys. Lond. List of Presents December 12, 1889. I. The Relation of Physiological Action to Atomic Weight. By Miss H. J. JOHNSTONE, University College, Dundee, and THos. CARNELLEY, Pro- fessor of Chemistry in the University of Aberdeen II. An experimental Investigation into the Arrangement of the excitable Fibres of the Internal Capsule of the Bonnet Monkey (Macacus sinicus). E. Brervor, M.D., F.R.C.P., and Victor Horstey, B.S., E.R.S. (from the Laboratory of the Brown Institution). III. On the Effect of the Spectrum on the Haloid Salts of Silver. By Captain W. ve W. Asyey, C.B., R.E., D.C.L., F.R.S., and G. 8S. Epwarps, C.E. IV. Magnetic alee of foes of Nickel and Jron. By J. Hopxtnyson, By CHARLES FE.R.S. List of Presents For continuation of Contents see 2nd page of Wrapper. Frs 18, 1890. Price Two Shillings and Sixpence. 1 13 18 21 21 22: 23 25 will ae nlm ane a SE ——— ee re: Cie map seme i : The Presence of an Carbon Flutings in the poco: | By J. Norman Lockyer, F.R.S. .— Mee i ie Ta, Some Observations on the Amount of Luminous ond Won tion emitted by a Gas Flame. By Sir Jounw Conroy, Bart., M. ie IV. On the Effects of Pressure on the Magnetisation of Cobalt. By 0. - i M.A., Fellow of King’s College, Cambridge 2 ee eh oan kie V. On the Steam Calorimeter. By J. Joby, MAL Be it ape “VL On the Extension and Flexure of Cylindrical and Spherical 1 Thin Elastic Shells. By A: B. ease E.R.S. : Neg eet ne List of Presents ‘ : . ats . ager ns: sh, ure ae Observations on the Amount of Luminous and Non-Luminous Badideon emitted by a Gas Flame. 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PAGE Observations on the Spark Discharge. By J. Joxy, M. We B. E. (Plates 1—6) 1 January 9, 1890. I. New Experiments on the question of the Fixation of Free Nitrogen. (Preliminary Notice.) By Sir J. B. Lawes, Bart., LL.D., F.R.S., and Professor J. H. Grrpert, LIAD., F.R.S. : : ; : ; 2 Se II. On Electric Discharge between Electrodes at different Temperatures in Air and in High Vacua. By J. A. Fuzmine, M.A., D.Sc., Professor of January 16, 1890. J. On the chief Line in the Spectrum of the Nebule. By J. Norman Locxyer, F.R.S. : : p : : : ; : «Zs II. Observations regarding the Excretion and Uses of Bile. By A. W. Mayo Rosson, F.R.C.S. : : : ‘ y i : 2g Til. The Theory of Free Stream Lines. By J. H. Micuett, Trin. Coll. Cam. 129 January 23, 1890. S i On a Photographic Method for determining ogee in Stars. By es Isaac Roperts, F.R.AS. . é : 4 ‘ Sco Meng II. Physical Properties of Nickel Steel. By J. 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