VIII. On the electrical phenomena exhibited in vacuo

The production of heat and light by electrical discharges: the manner in which chemical attractions are produced, destroyed, or modified by changes in the electrical states of bodies: and the late important discovery of the connection of magnetism with electricity, have opened an extensive field of enquiry in physical science, and have rendered investigations concerning the nature of electricity and the laws by which it is governed, and the properties that it communicates to bodies, much more interesting than at any former period of the history of philosophy. Is electricity a subtile elastic fluid ? or are electrical effects merely the exhibition of the attractive powers of the particles of bodies ? Are heat and light elements of electricity, or merely the effects of its action ? Is magnetism identical with electricity, or an independent agent, put into motion or activity by electricity ? — Queries of this kind might be considerably multiplied, and stated in more precise and various forms: the solution of them, it must be allowed, is of the highest importance; and though some persons have undertaken to answer them in the most positive manner, yet there are, I believe, few sagacious reasoners, who think that our present data are sufficient to enable us to decide on such very abstruse and difficult parts of corpuscular philosophy.