400 CAUSE OF INFLUENCE OF IONS. I 



Table II shows that the rate of endosmotic transport increases in 

 abnost neutral solutions of salts with increasing valency of the anion 

 and diminishes with increasing valency of the cation. Electrolytes 

 influence, therefore, the osmotic transport in exactly the same sense 

 in free and in electrical osmosis. This influence is in both cases an 

 additive effect of the oppositely charged ions of the electrolyte. In 

 the presence of the salt mentioned the watery phase of the double 

 layer is positively charged. The slight fall of level in the case of 

 CaCl2 and of BaCl2 must be ascribed to the pressure head of about 

 30 mm. solution existing at the beginning of the experiment; since 

 the same or a slightly more rapid fall of level occurs if no current 

 passes through the liquid. 



TABLE II. 



Relative Transport of Liquid by Electrical Endosmose in Approximately Neutral 

 Solutions, pH — 6.2. 50 Volts. 



Rise of level of 



liquid in manometer 



in IS min. 



m/512 KCl 



M/512K2SO4 



m/512 K4Fe(CN)6.. 

 m/1,024 K4Fe(CN)6 



m/512 CaCl. 



m/512 BaCla 



3.5 



6.5 

 20.0 

 22.0 











We will now show that the statements made for neutral solutions 

 are also true for alkaline solutions. In alkaline solutions the watery 

 phase of the double layer is also positively charged and the liquid is 

 transported to the cathode as in the case of neutral solutions. The 

 cathode was put into the glass tube and the rise of level in the glass 

 tube during the first 15 minutes after the current had become fairly 

 constant was used as a measure for the transport. The solutions were 

 brought to the same alkalinity as that of m/ 1,000 KOH and the pH 

 varied between 10.9 and 11.0 (Table III). 



The result is the same as before: the rate of endosmotic transport 

 increases in alkaline solutions with increasing valency of the anion 

 and diminishes with increasing valency of the cation. Electrolytes 



