REFERENCES.--De La Rive, “Electricity,” Vol. I. p. 203; Wilson, “Treatise on Electricity”; Wilson and Hoadley, “Observations on a Series of Electrical Experiments”; _Phil. Trans._, Vol. XLVIII. p. 347; Vol. XLIX. p. 682; Vol. LI. part i. pp. 83, 308, 331, part ii. p. 896; Vol. LIII. pp. 436, etc.; Vol. LXVIII. p. 999; Vol. LXIX. p. 51; also Hutton’s abridgments; Vol. X. p. 420; Vol. XI. pp. 15, 396, 504; Vol. XII. pp. 44, 147; Vol. XIII. p. 374; Vol. XIV. pp. 334, 337, 458, 480; “The Electrical Researches of the Hon. Henry Cavendish,” Cambridge, 1879, No. 125; L. E. Kaemtz, “Lehrbuch der Meteor,” Halle, 1832, Vol. II. p. 395. =A.D. 1746.=--Ellicott (John), of Chester, suggests a method of estimating the exact force of the electric charge contained in the Leyden jar by its power to raise a weight in one scale of a balance while the other scale is held over and attracted by the electrified body. This was the principle upon which Mr. Gralath constructed the electrometer shown in _Dantzig Memoirs_, Vol. I. p. 525. With reference to the experiments of Boze (A.D. 1738) and of Nollet (A.D. 1746) made with capillary tubes, he says that the siphon, though electrified, will only deliver the water by drops if the basin containing the water is also electrified. He explains Nollet’s observation, that the electric matter issues more sensibly from the point at the extremity of the conductor, by saying that the effluvia, in rushing from the globe along the conductor, as they approach the point are brought nearer together, and therefore are denser there, and if the light be owing to the density and velocity of the effluvia it will be visible at the point and nowhere else. Ellicott’s theory of electricity is founded upon the following data: (1) electrical phenomena are produced by effluvia; (2) these effluvia repel each other; (3) they are attracted by all other matter. If the word _fluid_ is substituted for effluvia, these data absolutely agree with those adopted by Æpinus and Cavendish, forming the basis of the only satisfactory theory of electricity hitherto proposed. REFERENCES.--Boulanger, “Traité de la Cause et des phénomènes de l’électricité,” Paris, 1750, p. 324; _Phil. Trans._ for 1746, Vol. XLIV. p. 96, and for 1748, Vol. XLV. pp. 195–224, 313; also the abridgments of John Martyn, Vol. X. part ii. pp. 324, 386, 389, 394; Hutton, Vol. IX. p. 475.