JACQUES LOEB 



683 



different potassium salts increases in the order I > Br > CI, where 

 the depressing effect of I is greatest. 



This order is the same regardless of the nature of the cation. Thus 

 Fig. 9 shows the same order of depressing effect of the anion on the 

 rate of diffusion of water through positively charged membranes in 

 the case of barium salts. 



^ 

 ^ 

 $ 



O 



"to 

 '-a 





180 



160 



140 



120 



100 



80 



60 



40 



20 



312 25B I^ 64 32 16 ^ 4 2 ^^^ 



Concentration of salt solution 



Fig. 8. The rate of diffusion of water through positively charged membranes 

 (pH about 3.0) and the density of charge of membrane are depressed by anions in 

 the order I > Br > CI. 



If we combine the results of the experunents on positively and 

 negatively charged membranes we can express them in the following 

 form. 



The accelerating and depressing effect of monatomic, monovalent 

 ions on the rate of diffusion of water through a collodion membrane 

 from the side of pure water to the side of the solution increases for 

 anions directly and for cations inversely with the magnitude of their 

 radius. 



