(433 ) 



If Ave introduce : 



f I = ƒ<' + IIT loij i\ 



ill which r is Ihc coiici'iUrnllon of the Ions, wo niav also write: 



L^- 



L 



A'i 



(f*'A--M';.-) + nrio'j-^ 



K. 



A'l 



{(t'r,-li',.,)'^-JiTlo!j 





{^) 



U. Now overvwhoi'o c/v =r cci (only in the hoimdai-y-layei' an 

 excess of posilixe oi- negative Ions is |)i'eseiil, owiiiji; to the for- 

 mation of the (lonblelayer), therefore also 



and so we find ') 1)3' addition of the two e(|ii;iti(>iis (5): 



'^ = è [('''ar'''r/,' - ('''a- -'^'a-.)] ■ • • • (6) 

 From this last relation it follows at once, that in (idute solutions, 

 where the quantities fi' are almost independent of tlie concentration, 

 f hi' poti'ntiiil-dijference A mill he also independent of the concentration. 

 Whedier iiuidi or litde KC/l is distributed through tlie two solvents, 

 we will always notice about the same potential-dilFerence A. 



If we deduct the two equations from each otiier instead of adding. 



then we obtain ( observing that 



RTlori 

 If now we put 



A', 





f^A-'^A'. 



^Vv-fVv. 



RTlonK,, 



A 



RT loo K 



a 



(7) 



(^0 



iu which AV and Kri are quantities, which dejieud on Hie nature 

 of the two solvents (and which in ddiite solutions will only be func- 

 tions of fi'n)j)('t'/f/.it.n^ — they are the so-called pdrlilldii-coefjlcients 

 of I he posili\e and negative Ions - — then (6) and (7) pass into 



A = — ton 



28 ''Kk 



(««) 





KkXKci (7a) 



1^ The formulii ((V) was given already, though with a .soinewlial (liriorciil notation, 

 by LuTiiKR [Z. f. I'll. (Ml. 19, Wdl (IS'.H))]. The first Ihciinodynamic theory of the 

 equilibrium of partition was given by ine hi a paper of 18U5 (Z. f. I'h. Gii. 18. "204—207), 



211 



Proceedings Royal Acad. Amsterdam. Vol. V. 



