54 POPULAR SCIENCE MONTHLY 



trie fields, and are neither refracted nor reflected. I would emphasize, 

 however, their ability to discharge an electrometer, as well as to influ- 

 ence the photographic plate. Their peculiarities have been recently- 

 ascribed to the fact that they represented aperiodic impulses given to 

 the luminiferous ether — which conveys no meaning to my mind, except- 

 ing that they can not be explained by the modulatory theory. The 

 velocity of the canal rays has been determined, and the mass of their 

 hypothetical particles measured by the amount of their deflection in 

 magnetic fields of varying strength; both values approximate those 

 found for the ordinary chemical atoms or molecules ; in the case of the 

 negative cathode rays, however, the velocities and mass correspond 

 to those assumed for the electrons. I confess to a serious difficulty in 

 harmonizing the notion of a corpuscular structure of the atoms with 

 the explanation given by the same school for the need of high vacua 

 for the production of cathode rays. It is said that the electrons must 

 have a considerable free path in order that they may travel with undi- 

 minished velocity toward the anode : but if the atoms, instead of being 

 compact elastic bodies, be mere nebulas of electrons, the relation of 

 whose sizes and interstices is comparable to that of the molecules in a 

 normal gas, it follows that a free electron, hurled vehemently forward 

 from the cathode, could pass quite through a number of atoms without 

 collision with any of their constituent corpuscles; the free path of the 

 electron is so enormous, on this hypothesis, that the order of its mag- 

 nitude could not be materially affected by the degree of rarefaction of 

 the gas customary in the Crookes tube. 



We must recollect, however, that the hypothesis, first elaborated by 

 Larmor, that the electrons are the primordial constituents of the atoms, 

 does not, like that of Prout, simply extend the limits of the divisibility 

 of matter. The electron is not to be considered as a small speck of 

 matter at all, but as a permanent manifestation of energy concentrated 

 on a minute portion of the luminiferous ether. This view and the 

 explanation of many phenomena on such a basis has been acclaimed as 

 the triumph of energetics, the final elimination of the conception of 

 matter. An unbiased reading of J. J. Thomson's Yale lectures, how- 

 ever, will impress anybody that he decidedly materializes both energy 

 and ether. Perhaps much of this materialization is purely symbolic, 

 to bring his mathematical reasoning within the comprehension of his 

 audience ; but to me it seems that an electric charge which has quantity, 

 mass, inertia, elasticity and expansibility, which obeys the laws of 

 hydrostatics, and virtually has a surface beyond which it can only 

 produce effects by the medium of mysterious lines of force, has a mar- 

 velous resemblance to the picture which the ordinary chemist's mind 

 would form of material substance. His ether is not only that puzzling 

 paradox, at once impalpable and inconceivably dense, rigid and fric- 

 tionless, which we have accepted as the whole means of explaining the 



