When gamma (or x-) rays fall on an atom of matter they cause it to discharge one or more of its electrons or corpuscles, the intermediate of the three emanations popularly included under the term x-rays. In this connexion they are called beta rays.
The professor points out that when gamma (or x-) rays produce this discharge from an atom
the beta rays to a large degree continue the line of motion of the gamma rays, as if the latter pushed them out of the atoms; and, lastly, that the number of the beta rays depends on the intensity of the gamma rays.
The gamma ray, entering an atom, pushes out a corpuscle, a beta ray, and takes its place. It behaves, in fact, as if it were itself a corpuscle, and the word ray is not well descriptive either of it or the beta. Nor can it be a mere ether-pulse. The professor suggests that it is a corpuscle, an electron, which has had the ordinary negative charge of electricity proper to electrons neutralized by a positive. Then he proceeds:
Many insist that my neutral corpuscle is too material, and that something more ethereal is wanted, for it appears that ultra-violet light possesses many of the properties of x- and gamma rays.... They propose therefore a quasi-corpuscular theory of light, gamma and x- rays being included.... The light corpuscle which is proposed is a perfectly new postulate. It is to move with the velocity of light ... and to be capable of replacing and being replaced by an electron which possesses the same energy but moves at a slower rate, and, of course, it has to do all that the old light waves did. The whole situation is most remarkable and puzzling.
So at this rate matter consists of molecules, as before; which consist of atoms, as before; which consist of electrons, as before—but may also in part or altogether consist of still more ethereal corpuscles which are light.
It is but a step to the suggestion that the electrons consist of light corpuscles, standing to them as they stand to the positive or negative atom of matter. Then metals will be crystallized light.
But whence the light corpuscles? How did they manage to get born in space? An answer to this question means a step-over from science into metaphysics. If and when we have reached the last line of matter we must begin to consider consciousness.
Intellectual light, spiritual light—we think we are using only metaphors in those phrases. Possibly we are not. Physical light may be the last stage of higher lights. If physical light is divine thought-energy appealing to our sense, it may have passed down through higher stages at which it appeals only to mind and heart and spirit.