THE SEARCH FOR PRIMAL MATTER 



duced by the Rontgen rays was that the rays 

 acted as a nucleus upon which the water might 

 condense. Without such a nucleus there would 

 be no fog. There were control experiments which, 

 showed that the rays of ultra-violet light the rays 

 of light so short that our retina will not respond to 

 them have the same power to produce such a fog 

 as I have described. Other observations, which it 

 would take one too far afield to consider here, indi- 

 cate that the particles produced by the ultra-violet 

 rays and the cathode rays are, perhaps, identical. 



There was further ground for belief that each 

 separate particle, and only a single particle, could 

 act as a nucleus for Mr. Wilson's fascinating fogs. 

 If each drop, then, contained a single particle, here 

 was a means of actually counting the number of 

 particles concerned in a given amount of cathode 

 radiation. It would likewise supply the measure 

 of the mass of each particle. But this was simply 

 the value of m in Professor Thomson's equation. 



The mass of each particle known, the charge of 

 electricity it bears is equally known. The problem 

 is solved. 



It was solved, but the result was so astonishing, 

 so utterly upsetting of all existing theories, that it 

 is only since Professor Thomson's experiments have 

 been repeated and verified in all the lands of the 

 earth and, happily, confirmed by other experi- 



'57 



