XXIV.] FROM A PHYSICAL STANDPOINT. 189 



recent researches of Professor J. J. Thomson, made in connection with 

 his work on the cathode rays. 



Since the cathode rays produce -luminous effects their path can be 

 traced, hence it is known that they are deflected in a magnetic field. 

 This deflection depends upon the mass of each particle and the electric 

 charge it carries, that is, upon their ratio, m/e. This ratio Professor J. 

 J. Thomson finds to be about yj^th of the corresponding value for the 

 hydrogen ion in ordinary electrolysis. 



At the same time it has been found by Professor J. J. Thompson 

 and Mr. Townsend that the electric charge e is the same for cathode 

 rays and a hydrogen ion. The m/e in fact may be regarded as inde- 

 pendent of the nature of the gas. Since then the m/e of the hydrogen 

 ion is 700 times greater than in the case of cathode particles, the m, the 

 'smallest mass whose existence Professor J. J. Thomson has glimpsed, 

 can only be about T J^th of the hydrogen ion. 



Professor J. J. Thomson writes : l 



" The explanation which seems to me to account in the most simple 

 .and straightforward manner for the facts is fc*unded on a view of the 

 constitution of the chemical elements which has been favourably enter- 

 tained by many chemists ; this view is that the atoms of the different 

 chemical elements are different aggregations of atoms of the same 



kind. 



* * * * * * 



" Thus on this view we have in the cathode rays matter in a new 

 state, a state in which the subdivision of matter is carried very much 

 further than in the ordinary gaseous state : a state in which all matter 

 that is, matter derived from different sources, such as hydrogen, 

 oxygen, &c. is of one and the same kind, this matter being the sub- 

 stance from which all the chemical elements are built up. 



* * * * * * 



" The smallness of the value m/e is, I think, due to the largeness of 

 <? as well as the smallness of m. There seems to me to be some evi- 

 dence that the charges carried by the corpuscles in the atom are large 

 compared with those carried by the ions of an electrolyte." 



Thus the whole question of dissociation has been advanced 

 because while on the chemical view we have to deal with intrinsically 

 different kinds of matter from element to element, on the view of Pro- 

 fessor J. J. Thomson m is a constant for every element, reminding one 

 of Rydberg's general formula for series in which N is practically a 

 constant for every element, although Eydberg acknowledges slight 

 variations which may be due to errors of observation. 



1 Phil. Mag., vol. xliv, p. 311, October, 1897. 



