380 



360 



340 



320 



^ 300 



"I Z80 



^ 260 



C 240 



"io 220 



^t=r 200 



^ 180 



G) 160 



"§ 140 



."S 120 



% 100 



80 



60 



40 



20 



Jl H H H H H M M M M M iM ?M 

 2048 1024 512 256 128 64 32 IB" 8 4 2 ^^ - - 



Concentration o[ salt solution 



Fig. 6. The rate of diffusion of water through a positively charged mem- 

 brane and the density of charge of the membrane are increased by the mono- 

 valent, monatomic cations in the order Li > Na > K > Rb. Solutions acid 



(pH about 3.0). 



681 



