﻿Molecular Thermodynamics. 635 



Cj being 2cj. Now t JC and tj a , being constants peculiar to 

 the particular ions constituting the electrolyte, it is plain 

 that we have here a possible explanation of the specif"' 

 divergences of the simple uni-uni-valent electrolytes at and 

 below (say) tenth-normal concentration, not involving the 

 rejection of the "point-charge" assumption, at these concen- 

 trations. 



As might be expected, the limiting " law " be 1 ' 2 for <p or 

 log 7, found by G. N. Lewis to apply, below (about) 

 hundredth normal solution, to uni-uni-valent electrolytes, 

 can be extended to cover the data to higher concentrations 

 in the form (bcV 2 + ac) , where a, unlike 6, is specific, or 

 peculiar, to the particular electrolyte. But, further, the 

 values of a required are quite of the order of magnitude to 

 accord with the interpretation of (104). 



One other particular case of (103) may be cited, viz. the 

 case of two electrolvtes together, the concentration of 

 the one, j, being negligible compared with that of the 

 other, i 3 so that C» is practically 2c i} and t depending on i 

 only can be written (it ic + ^t ia ), whence 



log 7, = (tjc + tja+tic+^Vi + ifiQi 1 ' 2 , • (105) 



in which, it is seen, the specific properties fas regards solva- 

 tion) of the four ions present enter very simply, symmetrically 

 and additively. 



These Hew brief and verylimited illustrations must suffice 

 for the present rather lengthy paper. 



Appendix I. — The Expansions of U and V. 



• 



As in the previous treatment of " complex solvents " the 

 full consideration of the expansions of CJ and V, the total 

 energy and volume of the solution, is postponed, but one 

 point concerning the simple linear forms applying to 

 ' ; perfect solution " is briefly considered. 



"We have then the " molecular " expressions 



U = Xn 0l u 0l + ^n s [(l — X s )u So + Sj; Sl u Sl ],^ 

 Y = Xn 0l v 0l + Xn s [{l-X s )v So + X^v Sl ]A, . (106) 

 Q = tn 0i qo l + Sn s [(l—X s )q So -\-Xx Si q Sl ] J 

 and, starting from the results of the previous paper, we have 

 U = M i*m + Xuo 1 &n 0l + Sw 8 [(l — X s )u So + Xx Sl u Sl ] 



■= M Vm + 2,u 0l &n 0l + Sn s [ (1 - Xs)u 8o + ^v Sl u 8l — a,w M ] . 



