266 



ELECTRIFICATION OF WATER 



of diffusion of Al2Br6 through the two types of membranes; the non- 

 treated membrane being shghtly more permeable. The difference 

 was, however, much too small to account for the difference in the 

 osmotic behavior of the two types of membranes. 



It was, therefore, necessary to look for another explanation in the 

 different osmotic behavior of the two types of membranes. It seemed 

 these differences would find their explanation if it could be proved 

 that water diffuses through collodion membranes not treated with 

 gelatin in the form of positively charged particles even in the presence 

 of acids or salts with trivalent or tetravalent cation. For this purpose 

 the method of electrical endosmose was applied. Identical solutions 

 of LaCla were put inside and outside a collodion bag not treated with 

 gelatin and a ciirrent (of about 4.8 milHamperes and about 90 volts) 

 was sent through the solution. The water migrated to the cathode, 

 showing that its particles were positively charged in the presence of 

 LaCls. When the same experiment was repeated with membranes 

 previously treated with gelatin it was found that water is negatively 

 charged in the presence of solutions of salts with trivalent cation. 

 It was furthermore possible to show that in the presence of acids 

 water diffuses through membranes not previously treated with gelatin 

 in the form of positively charged particles. 



We can now understand why it is that water cannot diffuse through 

 collodion membranes not treated with gelatin into solutions of salts 

 with trivalent cation, e.g. AICI3 or LaCls (in the region of electrical 

 effect), since these particles of water carrying a positive charge are 



