﻿614 Mr. Bernard Cavanagh on 



and, referring to (3), while remembering 



S^ + Cl-X.) = 1, 

 we obtain 



= r [d\og (S+« c)-|i log a+mcy] 



+ 2^dG Sl ' + (1-X s )<ZGU,'-«,<KJm' ; (17) 

 whence (14) gives, as alternative to (15), 



S=^- R [ l0 ^7^r7 + jl^ (1+SC) 



« +77/ C 



+ a 



m u u = u ... (18) 



where 



.a s = ( [(i-x s yGj + 2^G s /-a^G M ']. . (i9) 



c^o 



Comparing (15) and (18), we obtain 

 Rlog^— ^=r( Sd.log(l.+ mC)-(G s -G So '),. (20) 



1 A «0 J n _™ 



c=o 

 or 



Mlog(l-X s ) = R^log(l + wC) 



+ [* s dGu' + XsdG SQ '-2x Sl da si '], (21) 



which could be obtained independently from (7) and (8) 

 with (3), and then used to get (18) from (15) ; but the 

 above derivation from the physically significant equation (10) 

 appeared more interesting, and brings out an analogy with 

 the previous problem of " complex solvents." 



When there is present only one solute (s) (but any number 

 of solvates thereof), (18) can also be obtained easily, by 



means of the Gibbs fundamental relation, from ^^r . 



Olvlo 



The general terms being G s in (18) and G So ' in (15) 



we see that the division into " linear " and " general >r 



