ELASTICITY AS A MODE OF MOTION. 145 



air of the theatre. Each ring was circular, and 

 its motion was steady when the aperture from 

 which it proceeded was circular, and when it 

 was not disturbed by another ring. When 

 one ring was sent obliquely after another the 

 collision or approach to collision sent the two 

 away in greatly changed directions, and each 

 vibrating seemingly like an indiarubber band. 

 When the aperture was elliptic each undisturbed 

 ring was seen to be in a state of regular vibration 

 from the beginning, and to continue so throughout 

 its course across the lecture-room. Here, then, 

 in water and air was elasticity as of an elastic 

 solid, developed by mere motion. May not the 

 elasticity of every ultimate atom of matter be 

 thus explained ? But this kinetic theory of matter 

 is a dream, and can be nothing else, until it can 

 explain chemical affinity, electricity, magnetism, 

 gravitation, and the inertia of masses (that is, 

 crowds) of vortices. 



Le Sage's theory might give an explana- 

 tion of gravity and of its relation to inertia of 

 masses, on the vortex theory, were it not for the 



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