102 



ELECTRIFICATION OF WATER AND OSMOTIC PRESSURE 



concentration of cane sugar for each of these salts in the way described. 

 Table II gives the values observed after 30 minutes. The gelatin 

 solutions had a pH of 3.5. 



Using the same criterion as before we find that the balancing con- 

 centration of cane sugar lies for gelatin sulfate between 3m/32 and 

 m/8 and for all the others between 3m/16 and m/4. In other words, 

 the balancing concentration possesses for gelatin sulfate about one- 

 half the value found for the other salts. 



The writer has already published measurements of the osmotic 

 pressure of 1 per cent solution of different gelatin salts. The osmotic 



TABLE II. 



Nature of gelatin salt used. 



Gelatin chloride 



" nitrate 



Monogelatin oxalate. . . . 

 " tartrate... 



" phosphate 



" citrate..., 



Digelatin sulfate 



Change of level of liquid in the manometer tube of different concen- 

 trations of cane sugar solution when immersed in 1 per cent solu- 

 tions of gelatin acid salts of pH 3.5, after 30 min. 



Concentration of cane sugar solution. 



-19 

 -16 

 -20 

 -19 

 -16 

 -11 

 -19 



pressure varies for the same concentration of a gelatin salt with the 

 pH of the solution and is a maximum at a pH of about 3.4. It was 

 found that the maximum osmotic pressure of a 1 per cent solution 

 of gelatin chloride, gelatin bromide, gelatin nitrate, gelatin acetate, 

 monogelatin oxalate, monogelatin tartrate, monogelatin phosphate, 

 and monogelatin citrate is about 320 mm. of the gelatin solution; 

 while for a 1 per cent solution of gelatin sulfate the highest pressure 

 obtainable is about 130 mm. This is in satisfactory agreement with 

 the ratio we should expect on the basis of the influence of the anions 

 on the rate of diffusion of the negatively electrified particles of water. 

 We considered it necessary to obtain also the curves for the increase 



