SURFACE TENSION OF AQUEOUS SOLUTIONS. BARNES. 57 



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 



where v^, v^ are the volumes, and n jt ?? 2 the concentrations of 

 the solutions mixed, n 0il , 1*^2 the specific molecular conductivi- 

 ties of simple solutions of the electrolytes at infinite dilution, 

 ! and 2 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- 

 ments becomes : 



fe=i( I 1 Mooi4-a n sM , 9 )- 



Of the data requisite for calculating k, the n's were obtained by 

 chemical analysis, the 's by Prof. MacGregor's method, while 

 the jw^'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 p is 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. 



