On both the two-fluid and the one-fluid theories, as we have seen, the particles of the positive fluid repelled each other by forces varying inversely as the square of the distance between them—as shown by both Æpinus and Coulomb. This is true also of the particles of the negative fluid. The particles of the positive fluid attracted those of the negative fluid. In Franklin’s one-fluid theory it was the ordinary particles of matter which attracted the positive fluid and repelled one another. Both theories from their very nature imply, as Sir J. J. Thomson long ago (1906) pointed out, the idea of action at a distance. In his very interesting book, “Matter and Energy” (1912), Professor Soddy says: “All electrical phenomena can be explained as well on the one-fluid as on the two-fluid idea, but our ignorance at the present time as to whether there are two kinds of electricity or one is fundamental. Until the question is settled, the hopes that have been entertained that, through the study of electricity, we shall be able to arrive at a philosophical explanation of matter, are likely to prove unfounded.” Our modern view of electrification bears a close resemblance to the one-fluid theory of Franklin, whether we suppose there is one kind of electricity, or two kinds. At all events, if there be such a separate force, or such units of energy, as “positive” electricity, it has never been isolated, as have been the negative atoms or electrons. Negative electrification is but a collection of these negative corpuscles or unit charges. The particles of the “electric fluid” of Franklin correspond to these electrons. “Instead of taking, as Franklin did, the electric fluid to be positive electricity, we take it to be negative,” says J. J. Thomson, in his “Corpuscular Theory of Matter” (1906). And “the transference of electrification from one place to another is effected by this motion of corpuscles from the place where there is a gain of positive electrification to the place where there is a gain of negative. A positively electrified body is one that has lost some of its corpuscles.”[22] FOOTNOTES: [14] Jeans, J. H., “Electricity and Magnetism,” Page 483, 1911. [15] Benjamin Franklin was first to show (in a letter to Peter Collinson, written October 19, 1752) that lightning and electricity are one and the same thing. He was also inventor of the lightning-rod. [16] “Potential” is analogous to level (or pressure) in hydrostatics or mechanics. [17] For further explanation, see Shipley, Maynard, “The A. B. C. of the Electronic Theory of Matter,” Little Blue Book Series, No. 603. [18] See, in this connection, Shipley, _Op. cit._ [19] A very similar hypothesis was read before the Royal Society by Henry Cavendish, in 1771, the work of Æpinus being unknown to him at the time.