﻿2 Morris- Aire y, On the Rigidity of Gelatine. 



Dr. Albert Griffiths," in his experiments on the rate 

 of diffusion of salts in water, uses plugs of jelly to prevent 

 convection currents. Occasionally the plugs are subjected 

 to small differences of pressure, and are distorted to an 

 extent which depends, among other things, on the rigidity 

 of the jelly. On obtaining an approximate formula for 

 the distortion, it was seen that the behaviour of a cylin- 

 drical plug of jelly affords a convenient means of deter- 

 mining the coefficient of rigidity. 



In Fig. I, ABCD represents a circular cylinder of 

 jelly contained in a tube EF with rigid walls. 



^ 



2 



Fig. i. 

 On applying a downward pressure to the upper sur- 

 face of the plug, it takes the form AOB, DGC ; and as 

 the jelly may be considered incompressible, the assump- 

 tion may be made that the lower surface CGD has exactly 

 * Phil. Mag. XI A II.. 1X90, p. 530. 



