KINETIC OR MECHANICAL VIEW OF NATURE. 89 



reflexion and refraction and other properties are con- 

 cerned. Luminous waves are now considered by many 

 physicists to be merely electro-magnetic waves of short 

 wave length and great frequency, such as the organ of 

 vision is capable of perceiving in the form of light. 

 The electric and magnetic medium is identical with the 

 luminiferous ether, postulated by Young and Fresnel, 

 and rays of light are merely an electric and magnetic 

 disturbance propagated as a periodic or wave motion. 



These discoveries and theories have gone a long 54. 



. . , Destructive- 



wav to destroy the older astronomical view or natural effect of 



the new 



phenomena, which explained many effects by the action 

 at a distance of particles of ponderable or imponderable 

 matter. The firm conviction has taken hold of the t 

 modern scientific intellect or imagination that space is a 

 plenum filled with a continuous medium, and that the 

 undoubted atomic nature of ponderable matter may be 

 owing merely to a specific and unmodifiable form of 

 motion with such properties as Lord Kelvin has shown 

 to belong to vortex filaments. The difficulty still re- 

 mains how to explain the phenomenon of gravitation as 

 well as the increased amount of inertia or mass which , 

 belongs to all ponderable matter as compared with that 

 material substance which we call ether. 



The reason why Maxwell abandoned his earlier 

 schemes, in which he tried to construct a mechanical 

 model of the electro-magnetic field, is not quite clear. 1 

 The idea has, however, been taken up by others, and 

 elaborate descriptions have been attempted, by which the 



1 A suggestion regarding this is given by Dr J. Larmor in ' yEther and 

 Matter,' p. 28. 



