94 



THEORY OF COLLOIDAL BEHAVIOR 



and the curve for HC1 coincides practically with that for NaCl, 

 as our theory demands. 



That the depression of the viscosity of gelatin chloride due to 

 the presence of a salt is exclusively determined by the anion of 



Concentration 



FIG. 29. The depressing effect of equal molecular concentrations of NaCl, 

 CaCh, and LaCU on the relative viscosity of 0.8 per cent gelatin chloride solution 

 of pH 3.0 is roughly in proportion to the concentration of the Cl ions in the 

 solutions; i.e., as 1:2:3. 



the salt and that the cation has no augmenting effect is shown 

 in Fig. 29, where the influence of NaCl, CaCl 2 , and LaCl 3 upon 

 the viscosity of gelatin of pH 3.0 is represented. Fifty cubic centi- 

 meters of a 1.6 per cent solution of gelatin chloride of pH 3.0 were 

 added to 50 c.c. of a solution of different concentrations of each 

 salt as described, the pH being kept at 3.0. It is obvious from 



