36 PROCEEDINGS OF THE AMERICAN ACADEMY. 



In an investigation which I am now making on cells of the above type 

 I have attempted a verification of these equations in the following way. 



7* 



Choosing two solvents in which the value of In — may be neglected, 

 namely, water and a mixture of alcohol and water, then if t'g be made 



d TT 



equal to Vy, -pj^ should equal zero. Unfortunately the dissociation in 



alcohol-water mixtures of the salts that are available for our purpose 

 has not hitherto been determined. If the two solutions are made up 

 with equivalent amounts of the original salt, then the concentration of 

 the ions in the alcohol-water solution will be less than that in the water 

 solution on account of the greater dissociative power of water. In the 

 following cells, made up in this way, we should expect, therefore, a small 

 temperature coefficient, and moreover, since the electrode in contact with 

 the water solution is found to be negative, this temperature coefficient 

 should be negative. 



The following table gives the results obtained for the cells : — 

 (1) Zinc; zinc sulphate, tenth normal, in water and fifty per 'cent ethyl 

 alcohol. (2) Zinc ; zinc sulphate, tenth normal, in water and fifty per 

 cent methyl alcohol. (3) Cadmium; cadmium sulphate, tenth normal, 

 in water and sixty per cent ethyl alcohol. (4) Thallium; thalliiia 

 sulphate, hundredth normal, in water and twenty-seven per cent ethyl 

 alcohol. (5) Thallium ; thallium sulphate, hundredth normal, in water 

 and forty per cent methyl alcohol. 



