"According to the view... on the Continent, matter... included electrical corpuscles in instantaneous interaction. This approach... goes back to André-Marie Ampère and Ottaviano Mossotti in the 1830s, and can be found in a rudimentary form as early as 1759, in... Franz Æpinus. Later in the nineteenth century it was greatly developed by several German physicists, including Rudolf Clausius, Wilhelm Weber, and Karl-Friedrich Zöllner. In these theories, hypothetical electrical particles were considered to be the fundamental constituents of both matter and ether. ...with the increasing popularity of Maxwellian field theory (where electrical particles have no place), the theories were given up by most physicists. ... In 1874 Stoney proposed the "electrine" as a unit electrical charge, and in 1891 he introduced the "electron" as a measure of an atomic unit charge. ...Helmholtz argued the cause of "atoms of electricity" in his Faraday Lecture of 1881. The Stoney-Helmholtz electron could be both a positive and a negative charge and was... conceived as a unit quantity of electricity rather than a particle residing in all forms of matter. ...Stoney associated his electron not only with electrolysis but also with the emission of light. In 1891 he suggested that electrons rotating in molecules or atoms might be responsible for spectral lines..."