﻿Manchester Memoirs, Vol. xlix. (1905), No. 4. 5 



EF, some of the mercury is forced along the capillary tube. 

 The cavity at the other end is then filled with water in the 

 case of pure gelatine and with salt solution in the case 

 of jellies containing salts. The latter prevents any 

 diffusion ot the salt out of the jelly, which would occur if 

 pure water was placed in contact with it. 



The reading of the end of the capillary column is 

 then noted and the height of the vessel LM varied. 

 Let /i = variation in height of LM. 



v = volume traversed by the jelly. 

 p = density of liquid in LM. 

 m = distance through which end of capillary column 



moves. 

 r= radius of capillary tube. 

 r\ = coefficient of rigidity. 

 It is easily seen that 



V S/r 2 m 

 Before applying the formula, experiments were made 

 with the object of testing its accuracy. 



Simple experiments with a single tube proved that for 

 a jelly which has been set for a few hours, m varies 

 directly as h. Portions of the jelly column were then 

 removed so as to diminish /, and the movements of a 

 capillary column for a constant variation of h were noted. 

 The results were 



Length of 

 Cylinder (/). 



Movement of 

 Capillary {in). 



Product 



1 3 "3 cm. 



0*30 cm. 



3'99 



97 n 



0-41 „ 



3'97 



6-4 „ 



0-63 „ 



4*o3 



