J.J. Thomson, Recent Researches in Elect. And Mag

Cathode Rays. J.J. Thomson, (Received October, 1897)

The experiments[1] discussed in this paper were undertaken in the hope of gaining, some information; is to the nature of the Cathode Rays. The most diverse opinions are held as to these rays; according to the almost unanimous opinion of German physicists they are due to some process in the æther to which–inasmuch as in a uniform magnetic field their course is circular and not rectilinear-no phenomenon hitherto observed is analogous: another view of these rays is that, so far from being wholly authorial, they are in fact wholly material, and that they mark the paths of particles of matter charged with negative electricity.

It would seem at first sight that it ought not to be difficult to discriminate between views so different, yet experience shows that this is not the case, as amongst the physicists who have most deeply studied the subject can be found supporters of either theory.

The electrified–particle theory has fur purposes of research a great advantage over the ætherial theory, since it is definite and its consequences can be predicted; with the ætherial theory it is impossible to predict what will happen under any given circumstances, as on this theory we are dealing with hitherto unobserved phenomena in the æther, of whose laws we are ignorant. The following experiments were made to test some of the consequences of the electrified-particle theory.

[1]Some of these experiments have already been described in a paper real before the Cambrige Philosophical Society (Proceedings, vol. IX. 1897), and in a Friday Evening Discourse at the Royal Institution (‘Electrician,’ May 21, 1897).