CH. x.] ZEEMAN EFFECT 113 



that if radiation were due to moving electrons, their 

 motion could not be handicapped by having very 

 much matter associated and moving with them. It 

 became possible, indeed, by making a measurement 

 of the amount of doubling undergone by the lines in 

 a given field, to ascertain how much matter was 

 associated with the revolving electric charge in any 

 given case ; in other words, to make a determination 

 of the electrochemical equivalent effective in radi- 

 ation i.e., of the ratio m/e. Indeed, Professor 

 Zeeman, with considerable skill, had made a rough 

 determination of this kind at a very early stage, when 

 he only saw the effect as a slight broadening of the 

 sodium lines ; and had come to the conclusion that the 

 electrochemical equivalent was quite different from 

 that appropriate to electrolysis, being some thousand 

 times smaller. He found, in fact, that the ratio e/m 

 had in this case also the notable value already 

 suspected in connection with cathode rays, viz., the 

 value 10 7 c.g.s. 



More recent measurements have confirmed this 

 estimate, and shown that the ratio of charge to 

 matter in the Zeeman case is practically identical 

 with the ratio of charge to matter in the cathode ray 

 case ; in other words, that whatever is flying in the 

 cathode rays is vibrating in a source of radiation ; and 

 that if the cathode rays consist of moving electrons, 

 radiation is due to vibrating or revolving electrons. 

 The more the details of the Zeeman effect are 

 studied, the clearer it becomes that the electron 

 theory attributed to it from the first by Zeeman and 

 H. A. Lorentz, as well as by FitzGerald and Larmor 

 in England, is satisfactory, though not as yet 

 fully and completely worked out. 



One of the earliest publications in England, both 



L.E. H 



