THE SEARCH FOR PRIMAL MATTER 



similar importance in e very-day affairs. Ideas like 

 this met with the same opposition that new ideas 

 always do, and a violent controversy ensued, which 

 has only very recently come to an end. Heinrich 

 Hertz, to whom is due the discovery of the Hertz 

 waves, which have done so good a turn to mankind 

 in giving us wireless telegraphy, took up the study 

 and showed that the cathode rays were not, as had 

 previously been supposed, stopped by solid bodies. 

 He was able to drive the cathode rays through gold- 

 leaf and produce a phosphorescent glow behind this 

 thin screen. This discovery was, in some sense, 

 the precursor of that of Professor Rontgen. 



A little later another young German, Philip Len- 

 ard, devised what amounted to a little window in 

 the tube, a window made of thin aluminum foil. 

 By means of this, Lenard was enabled to give the 

 cathode rays a means of exit, and, as Professor 

 Thomson remarks, was thus the first physicist to 

 cross the Rubicon between the inside and outside of 

 a Trookes tube. Then, by way of keeping up the 

 balance of pride between nations, a young French- 

 man, Jean Perrin, showed by an ingenious device 

 that the rays do, as Professor Crookes had sup- 

 posed, carry an electrical charge. 



It is here that the work of Professor J. J. Thom- 

 son began. By repeating and so elaborating M. 

 iVrrin's experiment as to set the question of a 



153 



