﻿Manchester Memoirs, Vol xlix. (1905), No. 4. 9 



copper sulphate. (Amount used is one fifth of the weight 

 of water in the gelatine solution.) 



The junction of the ascending and horizontal branches 

 is not nearly so abrupt as in the case of pure gelatine, 

 while the final value of the rigidity is slightly less than 

 that of the pure medium. The same holds for the addi- 

 tion of potassium chloride and sodium chloride which 

 were used in amounts calculated to give the same total 

 number of gram-molecules per cubic centimetre as in the 

 copper sulphate solution. The final values of the rigidity 

 in these cases are in the order of the weights of salts added, 

 which was also the order of the molecular weights of the 

 salts. There is not sufficient material here to speculate 

 on the actual manner in which the salts affect the proper- 

 ties of the jelly, but the smoothing of the curve is consistent 

 with the presence of a greater number of nuclei, in which 

 case the presumption would be that the electrolytic ions 

 of the salts act as nuclei. 



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TIME 

 Fig. 6. 

 This view is supported by the fact that substances 

 like sugar whose solutions are not accompanied by ions, 

 do not affect the rigidity of jellies with which they are 

 mixed. 



In carrying out these measurements great difficulty 



