732 



ELECTRIFICATION AND DIFFUSION OF WATER 



These experiments show first that the rate of diffusion of these five 

 salts occurs in proportion to their concentration and second that in 

 the same time almost equal numbers of molecules of LiCl, NaCl, KCl, 

 MgCl2, and CaBra diffuse from equally concentrated solutions into 

 the distilled water. (The diffusion velocity of KCl may possibly be 

 slightly larger than that of LiCl or NaCl.) 



Hence the fact that the liquid does not rise when the collodion bag 

 is filled with solutions of salts with a bivalent cation while it rises 

 when it is filled with salts with univalent cation of the same osmotic 

 pressure cannot be explained on the assumption that the salts like 

 MgCl2 or CaCl2 diffuse out more rapidly into distilled water than do 



salts of the type NaCl. The only other possible explanation is that 

 water diffuses more rapidly into a collodion bag filled with a solution 

 of a salt like NaCl than into a bag filled with a salt like CaCla of the 

 same osmotic pressure. 



A similar experiment was carried out with the rate of diffusion of 

 HCl and H2SO4. The results are given in Table IV. 



The quantities of acid diffusing out are again for each acid approxi- 

 mately in proportion to the concentration of the acid, and almost 

 equal numbers of molecules diffuse out from the same molecular con- 

 centrations of the two acids though the rate of diffusion seems to be a 

 trifle less for H2SO4 than for HCl. (The reader will notice that the 



