370 UNSUSPECTED RADIATIONS. 



black spots again are .such as if they had iiiulcro-oMo a hydroo-cn ))oiu- 

 bardiiieiit. Moreover, the spectroscope reveals the hydrogen line in 

 the glowing tubes.' But all this, while proving the presinice of 

 hydrogen in the vaeuuiu tul)es, does not speak against the hypoth(\sis 

 of J. J. Thomson, which still remains, up till now. the most })lausil)l(> 

 explanation of the kathode rays. 



And yet one feels that the last word even al)out these rays has not 

 yet been said. Dr. .loseph Larmor was quite right when he remarked, 

 in his suggestive address delivered bet\)re the British association at 

 Bradford.' that the study of eleeti'ieal discharge in i-aretied gases has 

 conduced us to enlarged knowledge ""of the fundamental relations in 

 which the individual molecules stand to all electrical ])henomena." I p 

 till now we t(^ok these phenomena in a block. We studied the sum 

 total of the actions of an infinity of molecules in a certain direction. 

 Now we are bound to (piestion the molecule itself as to its speed, its 

 behavior, and its c<)nstituti\'e ])arts. and we find that a mohilit}' of its 

 component parts nuist l>e taken into account insti^ad of the rigidity 

 with which we formerly endowed it. 



I'he philosophical ^■alue of this new mo\(' in electrodynamics — the 

 value of the principle of action being introduced into the theories of 

 vilu'ation of the fornu'rly "" iimuaterial"' ether- is inunense, and it is 

 sure to bear fruit in natural philosophy altogether. Kther itself, 

 after ha\ing resisted so long all attempts to seize its true characters, 

 becomes dissociated matter, tilling space and upsetting many an old 

 preconceived idea. No Avonder, then, if it takes us some time ))efore 

 our views are settled upon these new phenomena, so f idl of unexpected 

 revelations and philosophical consequences. 



If the kathode ra3's are in all i)robability streams of dissociated mole- 

 cules which are thrown oil" the kathode, what are, then, the Rontgen 

 or X-rays^ The}' certainh* originate from the former, either in the 

 spot where they strike the glass or, what appears more correct, within 

 the tube itself in the kathode stream. But are both of the same nature i 

 Rontgen himself indicates many points of resemldance between the 

 two, and considers them in his third memoir^ as "phenomena prol)- 

 ably of the same nature." Lenard goes even a step further. He rep- 

 resents them l)oth as parts of the same scale or of the same "magnetic 

 spectrum;'' the X-ra3^s, which are not deflected by a magnet, being at 

 one end of the scale, while a series of intermediate radiations connect 

 them with the kathode rays occupying the other end of the scale.* 

 Both provoke fluorescence, both produce similar photographic and 



^Dr. P. Villard, iu Revue Generate des Sciences, 1899, Vol. X, jk 101. 

 •-'Nature, the 6th of October, 1900, Vol. LXII, p. 449, gives it in full. 

 * Sitzungyberichte of the Berlin Academy of Sciences, 1897, p. 576; suuuued up in 

 various scientific reviews. 



*Annalen der Physik, 1897, Vol. LXllI, p. 253. 



