MATTER IN MOTION 111 



must in any case be made. The mass of a nega- 

 tive electron is very much less than the mass of 

 a positive electron or proton, and since we be- 

 lieve that these masses are due to what we call 

 the electric field about each electron, the one 

 field cannot be merely a replica of the other 

 field, only with sign reversed. Now if it could be 

 shown that between the ratio of these two masses 

 and the constant of gravitation there is some 

 simple relation, it would afford strong evidence 

 for the view that gravitation is a mere residuum 

 of electrical effects. However, if we should be 

 led by this kind or any other kind of evidence 

 to support such a view, it would presumably 

 not lead to the demolition but rather to the 

 amplification of the structure of modern gravi- 

 tational theory. 



Sometimes the scientist engaged in painting 

 his picture of nature achieves, by a few bold and 

 happy strokes of the brush, an effect so lifelike 

 and beautiful that we are tempted to exclaim, 

 "Do not touch it again, it is perfect." So the 

 masterstrokes of Newton gave to mechanics the 

 appearance of such completeness that many of 

 his followers cried: "This is the whole of sci- 

 ence. Given the motion and the masses of all 

 the particles in the universe, all past and future 



