EXPLORING THE ATOM 



ture is found in the electron. This infinitesimal par- 

 ticle, according to the theory of Sir Joseph Thomson, 

 grips the ether somewhat as material substances 

 grip the air, and its activities set up waves in the 

 ether that are as tangible as the waves that radiate 

 out from a pebble dropped into the smooth surface 

 of a pond. 



The ether waves set up by the electron vary in 

 length or degree of agitation. But they move 

 through space at a uniform rate of speed which has 

 been demonstrated to be about 186,000 miles per 

 second. Waves of a certain degree of agitation we 

 interpret as heat; waves of another order we inter- 

 pret as light red light or green or yellow or blue 

 or violet, accordingly as the waves are longer or 

 shorter. Still shorter waves produce ultra-violet 

 light, which affects the photographic plate, but is 

 invisible to the eye. Waves of yet another order 

 excessively long waves, namely constitute electro- 

 magnetic currents, such as are used in wireless 

 telegraphy. 



But, according to the view of present-day physics, 

 no one of these sets of waves would agitate the 

 ether were it not for the activities of the electrons 

 which, grouped in various fashions, are hurtling 

 hither and thither within the structure of every atom 

 of matter, or are dashing at break-neck speed from 

 one atom to another. 



It remains to be said, however, that there has 

 been a tendency in very recent years to challenge 

 the wave theory of light notwithstanding the seem- 

 ingly secure position it has held* for the better part 



133 



