262 



ELECTROCHEMISTRY 



cent of casein combined with 80 X 10"^ equivalents of base per 



gram: 



TABLE VII 



It is perhaps not without significance that in the above table 

 the first two differences are much more alike than the succeeding 

 differences. In solutions containing to 20 per cent of alcohol, 

 strontium caseinate is further from coagulation than correspond- 

 ing solutions of calcium caseinate and, as we have seen, A, in 



the equation Xy = -j^, approaches constancy. Having regard to 



the observed failure of the solutions of potassium caseinate in 

 75 per cent alcohol to conform to the law, and to the fact that 

 at an alcohol-concentration lying between 60 and 75 per cent, 

 solutions of potassium caseinate undergo a great and relatively 

 sudden increase in opacity, we may, I think, conclude that the 

 coagulation of a caseinate by alcohol is heralded by a failure of the 



solution to conform to the law ^v = -ri> connecting the percentage of 



alcohol in the solution with its conductivity. 



4. The Interpretation of the Law Xy = -^ . — As we have 



observed (Table III) the value of A is not only constant for all 

 dilutions of potassium caseinate, but also is very nearly constant 

 for all of the proportions of alcohol to water employed as solvents. 

 Provided A were rigorously constant we would obviously obtain 

 the relation: 



a^HoO 



a^aic. H,o 



constant 



for any given proportion of alcohol to water. This is the rela- 

 tion, suggested by Cohen (2), connecting the conductivities of 

 inorganic salts in mixtures of alcohol and water. Roth (12), 

 however, found that this rule does not strictly hold good for 



