Aepinus and the British Electricians: The Dissemination of a Scientific Theory

Abstract

FRANZ ULRICH THEODOSIUS AEPINUS set out his principal contributions to electrical theory in his massive 390-page Tentamen theoriae electricitatis et magnetismi, published in St. Petersburg in 1759. As is well known, his version of the onefluid theory of electricity differed from that which had been put forward ten years earlier by Benjamin Franklin in two crucial ways in particular. First, he denied the existence around electrified bodies of any extended atmospheres of electrical matter of the kind which had been postulated by Franklin. Second, where Franklin had invoked two kinds of interparticulate force in his account-a mutual repulsive force between particles of the electric fluid and an attractive force between particles of the fluid and particles of ordinary matter-Aepinus supposed in addition that, Newton's gravitational principle notwithstanding, the particles of ordinary matter mutually repelled each other. It is equally well known that some years later Henry Cavendish put forward an almost identical version of the theory, in a paper he read to the Royal Society of London in two parts, on December 19, 1771, and January 9, 1772.1 Furthermore, Cavendish freely acknowledged Aepinus' priority, although at the same time he claimed both that he had arrived at the theory independently (despite Aepinus' account having been published over a decade earlier) and that he had carried his treatment of it much further than Aepinus had done: