4 Art. 11. — K. Matsuno : 



concentrations were added t© each. During addition the tuhes 

 were vigorously shaken to ensure thorough mixing. In this way 

 t.ij(}_ I two sucli c/^ncentrations are 



obtained that the lower 

 does not show any percepti- 

 l)le change in five minutes 

 whereas the liigher does. 

 This concentration is then 

 more carefully examined 

 and the limiting concentra- 

 tion determined. In Table 

 I the limiting concentra- 

 tions corresponding to the 

 different salts are given. 

 For comparison the limit- 

 ing concentrations of a 

 number of simple electro- 

 lytes were determined with 

 the same sol. The results 

 are given in Table IV. (p. 

 ^ 8) 



■f S e 



Val ency 



The Valency Rule on Coagulation 



As regards the quantitative study of the effect of the valency 

 on the coagulation of hydrosols, Whetham [Pliil. Mag., Y. 48, 

 474, (1899)] deduced the following equation on considerations of 

 probabilit}^ of collision: 



C, : C, : C3 = K=^ : K^ : K\ 



where Ci, Ca and C3 are the molecular concentrations of coagulation 

 of mono-, di- and trivalent ions respectively, K is a constant. If 

 this be true, it must be a straight line when plotted, taking the 

 logarithm of the concentrations of coagulation and the valency of 

 the ions as its axes. This did not, however, liold good in the 



