of action at a distance was however strongly repudiated by Newton himself, and hardly ever became influential in the English school of abstract physics represented by investigators of the type of Cavendish and Young. More recently, the following out into modern developments of the mere idea of continuous transmission of physical actions gained for Faraday a rich harvest of fundamental experimental discoveries: while the general results obtained by von Helmholtz in the abstract theory of fluid motion have enabled Lord Kelvin to reconstruct on a precise scientific basis the notions of Leucippus and Descartes on the relation of matter to aether[1].
Meanwhile, irrespective of such general cosmical views, the development of electrical theory itself has been steadily tending to an atomic standpoint. It has been noted by Maxwell, and was afterwards very fully enforced by von Helmholtz, that the interpretation of Faraday's quantitative laws of electrolysis could only be that electricity is distributed in an atomic manner, that each atom of matter has its definite electric equivalent, the same for all kinds of atoms: and even the expressive phrase "an atom of electricity" was imported into the theory by Maxwell. The only difficulty in this mode of formulation related to the mechanism of transference of these atomic charges or electrons from one molecule of matter to another. The order of ideas to be presently followed out will however require us to hold that the atomic charge is of the essence[2] of each of the ultimate subatoms, or as we may call them protions of which an aggregation, in stable orbital motion round each other, go to make up the ordinary molecule of matter: so that the transference of electric charge will involve transference or interchange of these constituent protions themselves between the molecules, that is it will always involve chemical change, as Faraday held on experimental grounds must be the case.
