A.D. 1785.—Sigaud de la Fond, Professor at the Collège d’Harcourt in Paris, publishes in the latter city his “Précis historique et expérimental des phénomènes electriques,” wherein he states having, as far back as 1756, made use of a circular plate machine provided with cushions and similar in shape to that which many claim to have originated with Ingen-housz and with Ramsden. (See A.D. 1779 and A.D. 1768.)
Sigaud de la Fond is also the author of “Description d’un Cabinet de Physique” (1784), “Cours de Physique,” etc. (1786), “Examen.,” etc. (1803) and of several treatises on medical electricity.
References.—“Journal de Physique,” Vol. II. 1773; Figuier, “Exposition et Histoire,” Paris, 1857, pp. 50, 74–76, 178; Poggendorff, Vol. II. p. 927.
A.D. 1785.—In the “Nachricht von einer neuen Elektrisirmaschine des Herrn Walkiers von Saint Amand,” the last named gives a description of the electrical machine presented by him in 1784 to the Belgian Academy of Sciences.
It is also described and outlined in Delaunay’s “Manuel” named below, but, although very powerful in its effects, cannot be made readily available in consequence of its huge dimensions. M. Caullet de Veaumorel suggested the feasibility of changing the cylinders from a horizontal to a vertical position.
References.—“Lichtenberg’s Mag.,” Vol. III. 1 st. p. 118; Delaunay, “Manuel,” etc., 1809, pp. 14–16.
A.D. 1785.—Adams (George), mathematical instrument maker to his Majesty, writes an enlarged edition of his “Essay on Electricity,” etc., which first appeared the year previous and wherein, as its full title indicates, he endeavours to explain the theory and practice of that science and the mode of applying it to medical purposes. He illustrates many experiments and gives an Essay on Magnetism, in the treatment of which latter he acknowledges the valuable aid of Dr. J. Lorimer.
The fifth and last edition of the “Essay,” which was issued by William Jones in 1799, four years after Adams’ death, contains a communication on the subject of Medical Electricity by John Birch, the author of “Della Forza dell’ Elettricita,” etc., Napoli, 1778.
At p. 86 of the 1799 “Essay,” etc., Adams relates that, while M. Loammi Baldwin (“Memoirs of Amer. Acad.,” Vol. I. p. 257) held the cord of his kite during the approach of a thunderstorm, he “observed himself to be surrounded by a rare medium of fire, which, as the cloud rose nearer the zenith, and the kite rose higher, continued to extend itself with some gentle faint flashes.” At pp. 137, 186 and 222, he alludes to “A. Brook’s Miscellaneous Experiments and Remarks on Electricity,” etc., as well as to the Rev. John Lyon’s “Experiments and Observations of Electricity,” and refers to the “Journal of Natural Philosophy” (Vol. II. p. 438) for Nicholson’s experiments on the plus and minus of electricity.
A.D. 1785.—La Méthérie (Jean Claude de), French physicist naturalist, becomes sole editor of the “Journal de Physique, de chimie et d’histoire naturelle,” and publishes in Paris his “Essai Analytique,” etc., wherein amongst other observations he asserts that the electric spark results from the combination of oxygen with hydrogen.