The Evolution of the Sciences 



the apparent mass over the real mass is insig- 

 nificant at low speeds, but increases with the 

 speed concurrently with the energy communi- 

 cated to the surrounding air. 



Now all that we have to do is to apply this 

 observation to the infinitely small bullets called 

 corpuscles, and to the ether in which they pro- 

 gress. The electric charge, carried by the 

 corpuscle, gives rise to a true electric current, 

 which appears at each point of the trajectory 

 when the charge reaches it and disappears as 

 soon as the charge has passed. Now a current 

 of this description produces in the surrounding 

 ether perturbations called, in the language of 

 physics, induced currents, and these induced 

 currents, which accompany the electron on its 

 flight, absorb part of its energy, a part which 

 increases with the speed. The corpuscle has, 

 therefore, like the bullet, a true mass and an 

 apparent mass, the latter increasing with the 

 speed. The physicist, Sir J. J. Thomson, whose 

 name has already been mentioned, succeeded in 

 calculating the law of this variation, and found 

 that the apparent mass of the electron would 

 become infinitely great, at a speed equal to the 



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