MATTER, SPACE, AND TIME 



237 



slowly moving corpuscle, and compared these 

 values with the results of Kaufmann's experi- 

 ments. 



In this remarkable manner was it possible 

 to show that the electrical theory of mass is in 

 accordance with these striking and unexpected 

 experimental results. Nevertheless, as we shall 

 see later, the same consequence of high velocity 

 in changing mass may be shown to be a deduction 

 from the theory of relativity, without invoking 

 electric conceptions. 



We must now return to the story of the 

 modern atom, which we left to give an account 

 of the facts of radiation and the theory of a 

 luminiferous aether. To explain all the properties 

 with which we know the chemical atoms to be 

 endowed, and more especially their power of com- 

 plex radiation, a theory has been built up during 

 recent years, chiefly by Thomson, Rutherford, and 

 Bohr, which represents an atom as a structure 

 containing one or more electrons in orbital motion 

 round a centre. It would be difficult to explain 

 such results if the electrons were crowded to- 

 gether ; thus it seems necessary to suppose that 



