SURFACE TENSION OF AQUEOUS SOLUTIONS.—BARNES. on 
Method of Calculating the Conductivity of Mixtures. 
According to the dissociation theory the specific conductivity 
of a mixture of two solutions of electrolytes is given by the 
equation 
SAG Ta) (erates 450M Hes») 
, are the volumes, and 7,,”, the concentrations of 
the solutions mixed, “,,;, 4,2 the specifie molecular conductivi- 
ties of simple solutions of the electrolytes at infinite dilution, 
«, and @, the ionization co-efficients of the respective electro- 
lytes in the mixture, and p is the ratio of the volume of the 
mixture to the sum of the volumes of the constituent solutions. 
This ratio was found, for the solutions used, to be practically 
equal to the unity: and as the volumes of the solutions mixed 
were in all cases equal, the equation applicable to my experi- 
where ¢,, v 
ments becomes : 
[ff SAI a pe oo eee) 
Of the data requisite for calculating k, the n’s were obtained by 
chemical analysis, the e's by Prof. MacGregor’s method, while 
the ,,’s, in the case of sufficient dilution, might be taken to be 
the same in value as in the case of simple solutions of the respec- 
tive electrolytes. 
Determination of p. 
As equal volumes of the simple solutions were mixed, the 
ratio expressed by pis equal to the ratio of the mean specific 
gravity of the constituent solutions to the specific gravity of the 
mixture. By referring to the following Table IV, it is at once 
seen that this ratio is practically equal to unity for the most 
concentrated solutions examined. 
