252 POPULAR LECTURES AND ADDRESSES. 



impulsive energies of the individual vortices 

 becoming lost in energy of smaller and smaller 

 vibrations. 



As a step towards a kinetic theory of matter 

 it is certainly most interesting to remark that 

 in the quasi-elasticity, elasticity looking like 

 that of an india-rubber band, which we see in 

 a vibrating smoke-ring launched from an elliptic 

 aperture, or in two smoke-rings which were 

 circular, but which have become deformed from 

 circularity by mutual collision, we have in 

 reality a virtual elasticity in matter devoid of 

 elasticity and even devoid of rigidity, the 

 virtual elasticity being due to motion, and 

 generated by the generation of motion. 



