KLECTltOMOTlVE FORCES IN THE VOLTAIC CELL. 



509 



tlicm 

 ciable 



Mifton 



•lit 



•8r> 



1-07 



r to show 



of data. 



■her than 



for the 



iron but 



into (lis- 

 3octz.^ I 



1-82 to -92 

 •:', (Smce) 



Jtbe former 

 lut it must 

 numbers 

 ae beats of 

 lof magni- 

 t tbe beUet 

 Ic apparent 



Tho agreement of tbo numbers, tbougli not exact, seems to mo too close 

 to be tbo result of accident. Ono may, I tbiiik, claim tliat tbo liypotliesi.s 

 wbenco tbe calculated numbers are obtained is justified by tbe figures as 

 far as tbey go. It is not put forward as a eonipleted tlieor^-, but only as a 

 first step to suob a tbcory. I believe it to bo a step in the direction of tho 

 truth, but it requires working out anil elaborating by a scientific chomist. 



IH. Not many nu^iisureni^ntsof nu'tai pairs liave been made even in air, 

 for mere permutations soeli as ci)])|)er-tin, tin-silver, itc, follow at onco 

 from the numbers gi\en above, by Volta's series law; but in gases other 

 than air ono has at present no experimental guidance, beyond tho barest 

 qualitative one given by !Mr. Drown, tliat copper-niekel rever.ses its sign 

 when chiinged from air to hydrochloric acid, and that copper-iron i& 

 reversed in sulphuretted hydrogen. ]3nt satisfactory observation in these 

 gases is difficult, because^ Ihey not only leial to attack the plates, but they do 

 attack them; a?ul so a film is formed and everything is rendered uncertain. 



Another complication results from the fact that when metals are 

 taken out of aii- and put into a foreign gas, they are already (;oated with 

 a film of oxygen, and it is not clear in wliat way this will alloct the action 

 of the new gas. It may have to be rei)laccd almost b}- substitution ; tho 

 affinity to be considered in chlorine, for instance, being something like 

 MjClo — M,0. In a compound like ilCl, the hydrogen also may have to 

 bo provided foi', the resulting chemical strain being, for instance, M,C1._, — 

 M,0 + Hj.^ — 2 (H,C1) ; but tbe consideration of tbe hydrogiMi aflinities 

 ■will not affect d!ffercnci:>s, and therefore Avill leave comparisons with ex- 

 periment unaH'ected. Taking the metals as clean, however, and without 

 air films, wo must suppose tbo following series to be rigbt : — 



Energies of Coinhinalinn of 31c fain villi Chlurinv . 

 Viilta Sarii's ill. thnf Gn.f. 



and Calculated 



JIc■l.^l 



Zinc . 



I. rail 



Iron . 

 Xicki'I . 



i C'opiKU- 



' ^lercury . 

 ' Silver 



j Ifydrogon. 



I 



Potassium. 

 ' Sodium , 



: f t '",('1. 



I :: 



II-,CI.. 



, f L'Cii'ci) 



|j l'(H,Cl,Aq) 

 1] 2(1I,C1) 

 I L L'(H.('l) 



! ( -'(K,n) 



jl :: 



No data 

 ThoiiistMi 

 F. and S. 

 Andrews 

 'I'loiiiscii 



F. and S. 

 Thonist'U 



F. and S. 

 Alviii . 

 'Jhomsen 

 F. and S. 

 Andrews 

 Tliornsen 



Hp.'it lit" 

 ('(iiiil)iniiti<-n 



1)7210 



10().V.t2 

 KlllilC) 

 82770 

 S'.M,-)(t 

 .S20.">(» 

 !M»;!02 



.■>ig;5o 

 u;i04s 



(!09SS 

 tiUKK) 

 r)876() 

 G'JtiOO 

 41000 



7S(;i(i 

 I7.")(i(; 



18174 

 211220 

 20l'.)20 

 20S!I.')2 

 !i).^;!SO 



( 'MlciiltUcd 



Volta Scriiis 



in Volts 



21 



18 



1-78 



1-12 



1-38 

 1-28 



•ut; 



4- 02 

 4 -24 



This series will bold, as far us difennces are concerned, fur hydro- 



