On a Thermo-electrical Phenomenon in Connection with Prof. Balfour Stewart's Paper on Terrestrial Magnetism

Abstract

IN the Philosophical Magazine for May Prof. Balfour Stewart, in his paper “On the Causes of the Solar-Diurnal Variation of Terrestrial Magnetism,” takes in one place (p. 443), for an example, the case of “an ordinary electric circuit, say of a circular shape, and horizontal, and heat it by causing some source of heat, such as a lamp, to travel slowly around it with a definite rate of progress.” He goes on to say that no current due to the heating will take place. So it would generally be thought. If, however, the experiment be even roughly tried, at all events with an iron or nickel wire, the contrary takes place. An account of the experiments, &c., which I have made on this subject, was read before the Royal Dublin Society on March 24, and will, in the course of time, be printed in the Society's Proceedings. Though there is a current in a wire on causing a heated portion to travel along it, it seems unlikely from the nature of the phenomenon that it could in any way be inferred that the higher air would similarly affect a current under the sun's heating.