Page:Scientific Monthly, volume 14.djvu/567

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THE ETHER THEORIES OF ELECTRIFICATION
559

Thus Lodge (Modern Views of Electricity, p. 349) says:

Is the ether electricity then? I do not say so, neither do I think that in that coarse statement lies the truth; but that they are connected there can be no doubt.

What I have to suggest is that positive and negative electricity together may make up the ether, or that the ether may be sheared by electromotive forces into positive and negative electricity. Transverse vibrations are carried on by shearing forces acting in matter which resists them, or which possesses rigidity. The bound ether inside a conductor has no rigidity; it cannot resist shear; such a body is opaque. Transparent bodies are those whose bound ether, when sheared, resists and springs back again; such bodies are dielectric.

A similar view to this was expressed in most text books on Electricity written in the English language between 1890 and 1900. Thus in his well-known text book on Electricity and Magnetism (Edition of 1895) S. P. Thompson attempts to define electricity as follows:

Electricity is the name given to an invisible agent known to us only by the effects which it produces and by various manifestations called electrical. These manifestations, at first obscure and even mysterious, are now well understood; though little is yet known of the precise nature of electricity itself. It is neither matter nor energy; yet it apparently can be associated or combined with matter; and energy can be spent in moving it. Indeed its great importance to mankind arises from the circumstance that by its means energy spent in generating electric forces in one part of a system can be made to appear as electric heat or light or work at some other part of the system; such transfer of energy taking place even to very great distances at an enormous speed. Electricity is apparently as indestructible as matter or energy. It can neither be created nor destroyed, but it can be transformed in its relations to matter and to energy, and it can be moved from one place to another. In many ways its behaviour resembles that of an incompressible liquid; in other ways that of a highly attenuated and weightless gas. It appears to exist distributed nearly uniformly throughout all space. Many persons (including the author) are disposed to consider it as identical with the luminiferous ether. If it be not the same thing, there is an intimate relation between the two. That this must be so is a necessary result of the great discovery of Maxwell—the greatest scientific discovery of the nineteenth century—that light itself is an electric phenomenon, and that the light waves are merely electric, or, as he puts it, electromagnetic waves.

In 1893 J. J. Thomson published his Recent Researches in Electricity and Magnetism, in which he carried the Faraday-Maxwell theory to a development almost as extreme as the later views of Faraday, to which reference has already been made. Only a short time later, he and his fellow workers succeeded in identifying the electrical fluid concerning whose existence there had been so much argument for 150 years. The development of the ether theory by Thomson should form the subject of another paper.