On electric currents induced by rotating magnets, and their application to some phenomena of terrestrial magnetism

Abstract

Speculative theories on the magnetic and electric relationship between the Sun and Earth lack all solid basis, until we can give an answer to the question, whether interplanetary space is to be considered an electric conductor or not. The question is not one which can at present be touched by any argument as to the possible amount of matter which space may contain, for the behavior of gases in our vacuum tubes is so much affected by the dimensions of the electrodes and of the vessel, that no conclusions can be drawn as to the electric behavior of molecules flying about in a boundless enclosure.It is my purpose to show how the behavior of the magnetic needle on the surface of the Earth may give us some information on the point. If it fails to do so it will be because the conductivity of space falls below a certain assignable value, and even that knowledge will be a gain.