[7] Faraday discussed the chemical theory of the pile and arguments in support of it in the 8th and 16th series of his Experimental Researches on Electricity. De la Rive reviews the subject in his large Treatise on Electricity and Magnetism, vol. ii. ch. iii. The writer made a contribution to the discussion in 1874 in a paper on “The Contact Theory of the Galvanic Cell,” Phil. Mag., 1874, 47, p. 401. Sir Oliver Lodge reviewed the whole position in a paper in 1885, “On the Seat of the Electromotive Force in a Voltaic Cell,” Journ. Inst. Elec. Eng., 1885, 14, p. 186.
[8] “Mémoire sur la théorie mathématique des phénomènes électrodynamiques,” Mémoires de l’institut, 1820, 6; see also Ann. de Chim., 1820, 15.
[9] See M. Faraday, “On some new Electro-Magnetical Motions and on the Theory of Magnetism,” Quarterly Journal of Science, 1822, 12, p. 74; or Experimental Researches on Electricity, vol. ii. p. 127.
[10] Amongst the most important of Faraday’s quantitative researches must be included the ingenious and convincing proofs he provided that the production of any quantity of electricity of one sign is always accompanied by the production of an equal quantity of electricity of the opposite sign. See Experimental Researches on Electricity, vol. i. § 1177.
[11] In this connexion the work of George Green (1793-1841) must not be forgotten. Green’s Essay on the Application of Mathematical Analysis to the Theories of Electricity and Magnetism, published in 1828, contains the first exposition of the theory of potential. An important theorem contained in it is known as Green’s theorem, and is of great value.
[12] See also his Submarine Telegraphs (London, 1898).
[13] The quantitative study of electrical phenomena has been enormously assisted by the establishment of the absolute system of electrical measurement due originally to Gauss and Weber. The British Association for the advancement of science appointed in 1861 a committee on electrical units, which made its first report in 1862 and has existed ever since. In this work Lord Kelvin took a leading part. The popularization of the system was greatly assisted by the publication by Prof. J.D. Everett of The C.G.S. System of Units (London, 1891).
[14] The first paper in which Maxwell began to translate Faraday’s conceptions into mathematical language was “On Faraday’s Lines of Force,” read to the Cambridge Philosophical Society on the 10th of December 1855 and the 11th of February 1856. See Maxwell’s Collected Scientific Papers, i. 155.
[15] A Treatise on Electricity and Magnetism (2 vols.), by James Clerk Maxwell, sometime professor of experimental physics in the university of Cambridge. A second edition was edited by Sir W.D. Niven in 1881 and a third by Prof. Sir J.J. Thomson in 1891.
[16] H. von Helmholtz, “On the Modern Development of Faraday’s Conception of Electricity,” Journ. Chem. Soc., 1881, 39, p. 277.