Does Matter Exist? 



initial velocity of the bullet. Thus, the explosive 

 force of the powder being known, we can also 

 measure the kinetic energy of the bullet, equal 

 to its mass multiplied by the square of its 

 velocity; when the kinetic energy and the 

 velocity are known the mass of the bullet is 

 determined. 



The study of kathode rays presents an 

 analogous problem. The velocity of our tiny 

 kathode projectiles is too high for the action of 

 weight to affect them, but other known forces are 

 capable of deflecting their trajectories. Under 

 the action of a magnet or an electrified body 

 we can see the kathode rays curving dis- 

 tinctly, and on the other hand we can measure 

 the kinetic energy communicated to the cor- 

 puscles by the electric discharge which puts 

 them in motion. 



The above comparison, though somewhat 

 vague, enables us at least to perceive the possi- 

 bility of experimenting with these atomic dusts. 

 In fact numerous experiments have been made 

 distinct both in principle and in experimental 

 disposition. Nevertheless the results obtained 



are remarkably concordant ; nothing short of this 



103 



