REFERENCES.--Ronalds’ “Catalogue,” pp. 369–371; Jean Morin, “Réplique,” Paris, 1749; A. H. Paulian, “Conjectures,” 1868; “Abrégé des transactions philosophiques,” Vol. X. p. 336; “Mémoires de mathématique,” etc., pour 1746, p. 22; “Journal des Sçavans,” Vol. CXVII. for 1739, pp. 111–115, and Vol. CXLII for 1747, pp. 248–265; “Medical Electricity,” by Dr. H. Lewis Jones, Philad., 1904, p. 2; “Mémoires de l’Acad. Royale des Sciences” pour 1745, p. 107; 1746, p. 1; 1747, pp. 24, 102, 149, 207; 1748, p. 164; 1749, p. 444; 1753, pp. 429, 475; 1755, p. 293; 1761, p. 244; 1762, pp. 137, 270; 1764, pp. 408–409; 1766, p. 323; “Leçons,” eighth edition, Vol. IV. p. 315; _Phil. Trans._, Vol. XLV. p. 187; Vol. XLVI. p. 368; Vol. XLVII. p. 553; also the following abridgments: Hutton, Vol. X. pp. 20, 295, 372–379, 446 (Dr. Birch); Vol. XI. p. 580; John Martyn, Vol. X. part ii. pp. 277–333, 382 (Folkes), 414. See the experiments of Etienne François du Tour, “Sur la manière dont la flamme agit sur les corps electriques,” in a letter addressed by him to Nollet in 1745, and in “Mém. de Mathém. et Phys.,” Vol. II. p. 246, Paris, 1755; also Zantedeschi and Faraday on the “Magnetic Condition of Flame” (Faraday’s “Exper. Res.,” Vol. III. pp. 490–493). =A.D. 1746.=--Wilson (Benjamin) (1721–1788), Secretary to the Royal Society, writes his “Essay toward an explication of the phenomena of Electricity deduced from the ether of Sir Isaac Newton.” In the chapter of Priestley’s “History” treating of the Theories of Electricity, he says: “With some, and particularly Mr. Wilson, the chief agent in all electrical operations is Sir Isaac Newton’s ether, which is more or less dense in all bodies in proportion to the smallness of their pores, except that it is much denser in sulphureous and unctuous bodies. To this ether are ascribed the principal phenomena of attraction and repulsion, whereas the light, the smell, and other sensible qualities of the electric fluid are referred to the grosser particles of bodies, driven from them by the forcible action of this ether. Many phenomena in electricity are also attempted to be explained by means of a subtile medium, at the surface of all bodies, which is the cause of the refraction and reflection of the rays of light, and also resist the entrance and exit of this ether. This medium, he says, extends to a small distance from the body, and is of the same nature with what is called the electric fluid.[50] On the surface of conductors this medium is rare and easily admits the passage of the electric fluid, whereas on the surface of electrics it is dense and resists it. This medium is rarefied by heat, which converts non-conductors into conductors.”