The Mathematical Theory of Electricity and Magnetism

Abstract

SINCE the third edition of this volume was published in 1915, the theory of relativity has been developed. It is now recognised that Maxwell's theory that the ultimate seat of electromagnetic and optical phenomena is in the æther may have to be modified or even abandoned. Experiments have proved that natural phenomena go on exactly as if there were no æther. We agree with the author in thinking that “the hypothesis that there is an aether may give a possible explanation of the phenomena, but the hypothesis that there is no aether provides an equally possible and very much simpler explanation.” Einstein's theory, unfortunately, although it helps us to discover the laws according to which phenomena occur, cannot lay claim to provide a mechanical explanation of them. Electricians know the importance of discovering the mechanisms by means of which electric and magnetic forces are transmitted through space. When the nature of these mechanisms is discovered, there will probably be a great advance in the practical applications of electricity. The theory of relativity, a very convincing explanation of which is given in this book, proves that it is unnecessary to presuppose an aether. This is welcome, as it is known that highly complex properties must be ascribed to an aether in order that it may explain both electrical and magnetic forces. In the kinetic theory of gases, forces and pressures are explained by a flow of momentum, and a similar explanation might be given of electrical, magnetic, and gravitational forces.

The Mathematical Theory of Electricity and Magnetism.

By J. H. Jeans. Fourth edition. Pp. vii + 627. (Cambridge: At the University Press, 1920.) 24s. net.