12 



ART. 8. — S. KAWAMUEA : COAGULATION OF COLLOIDAL 



same at different temperatures. And if it were not too venture- 

 some we miglit say that the higher the temperature the lower 

 will be the concentration of the electrolyte necessary to cause 

 noticeable coagulation. The relative viscosity of the completely 

 coagulated solution tends to decrease with the rising temperature. 

 But as the general features remain the same between 6° and 60°, 

 we may draw pretty general conclusions from observations at 

 the single chosen temperature of 25°. 



5. Effect of the Concentration of the Colloidal Solution. 



As has been demonstrated by Ceum the electrolyte is de- 

 composed in the act of coagulation, the anion being retained by 

 the gel formed. Hence the concentration of the electrolyte which 

 causes complete coagulation must vary with the concentration 

 of the colloidal solution. In order to test this point the follow- 

 ing measurements were made. 



TABLE 7. 

 Concentration of the colloidal solution = 0.025 ^^ alumina. 



TABLE 8. 

 Concentration of the colloidal solution = 0.0125G^ alumina. 



