﻿8 MoRRIS-AlREY, On the Rigidity of Gelatine. 



when a feeble jelly is beaten with a glass rod it becomes 

 fluid, uniting again into a solid on standing, the whole 

 operation being carried out without any perceptible 

 temperature changes. 



When the globules have grown so much that neigh- 

 bouring ones come into contact and grow together, the 

 character of the deformation under pressure will now be 

 a purely elastic one, and we should expect the sudden 

 disappearance of the hysteresis and the sharp shoulder 

 to the curve, which experiment actually establishes. 



In view of the well-known phenomenon of condensa- 

 tion of water vapour round ions as nuclei, experiments 

 were made to determine, if possible, the nature of the 

 nuclei in the process of solidification. It has long been 

 known that the addition of salts to gelatine solutions 

 modifies their rigidity, and accordingly various simple 

 salts were mixed with a gelatine solution of strength I in 

 20 and the progress of the solidification observed ; the 

 results are shown in Fig. 5. 



5x10* 



UATIfit I 20 



Gelatine izo * Cvbo, 



Gelatine i zO'KCL 



GELAT/ftf/M'tiaCl 



00000 



?S§e!????3t s 



The uppermost curve is that obtained with pure 

 gelatine. The next curve shows the effect of adding 



