382 



Mr. A. Frumkin on the 

 Fio-. 3. 



1 



• 





1 





(2) Salts with active cations. — Gouy * has shown that 

 similar to the active anions Br', I 7 , ON', there exist active 

 cations like N(C 2 H 5 ) 4 , S(OH 3 ) 3 . The electrocapillary curves 

 of salts of these anions have a normal ascending branch and 

 an altered descending one. For instance, the ascending 

 branch of a solution of [N(C 2 H 5 ) 4 ] 2 S04 coincides with the 

 ascending branch of a solution of Na 2 S0 4 , whilst the de- 

 scending branch of [N(0 2 H 5 ) 4 ] 2 S0 4 is considerably depressed- 

 But if the anion is active, the activity of the cation manifests 

 itself in the ascending branch as well as in the descending 

 one. Thus, comparing the electrocapillary curve of two 

 salts with an active anion like N(C 2 H 5 ) 4 Br and KBr, we see- 

 that their ascending branches are different. We must, there- 

 fore, admit that in presence of an active anion, the cation is 

 adsorbed even in the ascending branch. 



(3) The value of the horizontal displacement of the ascending' 

 branch. — If T K > 0, 



the ascending branches 



KT ^ logo 



and the horizontal distance between 



of two solutions whose concentrations are c x and c 2 must be 



greater than 



KT, c 2 



arlog-. 



* Ann. chim.phys. (8) ix. p. 87 (1906). 



n A ¥ 



