References.—Aglave et Boulard, “Lumière Electrique,” Paris, 1882, p. 18; Priestley, “Familiar Intr. to Study of Elec.,” London, 1786, p. 60; Phil. Trans., Vol. XXV. pp. 2327, 2332; Vol. XXVI, 1708–1709, pp. 82–92; Vol. XXIX, 1714–1716, p. 294 (with Brooke Taylor); also the following abridgments: Hutton, Vol. V. pp. 270, 307, 324, 344, 355, 411–416, 452, 509, 528, 696; Jones, Vol. IV. p. 295; Baddam, 1745, Vol. V. pp. 33–37, 41–43, 112, 114–117, 483; Thos. Thomson, “Hist. of the Roy. Soc.,” London, 1812, p. 430; Chemical News, Vol. II. p. 147; Nicolas Desmarets, “Expériences,” etc., Paris, 1754, in “Recueil des Mémoires de l’Acad. des Sciences.”
A.D. 1705.—Keill (John), M.A., F.R.S., Savilian Professor of Astronomy, is the author of “Introductio ad Veram Physicam, etc.,” of which other editions appeared in 1725, 1739 and 1741, and a good English translation of which was published at Glasgow in 1776.
The last named is entitled “An Introduction to Natural Philosophy, or Lectures in Physics read in the University of Oxford in the Year 1700.” In Lecture VIII he states: “It is certain that the magnetic attractions and directions arise from the structure of parts; for if a loadstone be struck hard enough, so that the position of its internal parts be changed, the loadstone will also be changed. And if a loadstone be put into the fire, insomuch that the internal structure of the parts be changed or wholly destroyed, then it will lose all its former virtue and will scarce differ from other stones.... And what some generally boast of, concerning effluvia, a subtile matter, particles adapted to the pores of the loadstone, etc., does not in the least lead us to a clear and distinct explication of these operations; but notwithstanding all these things, the magnetick virtues must be still reckoned amongst the occult qualities.”
A.D. 1706.—Hartsoeker (Nicolas), Dutch natural philosopher, friend of Christian Huyghens, while Professor of Mathematics at Düsseldorf, writes his “Conjectures Physiques,” four editions of which were published during the three years 1708, 1710 and 1712.
The Tenth Discourse of the Second Book (pp. 140–182) treats of the nature and properties of the loadstone and gives numerous observations concerning magnetical phenomena, which are well illustrated. He says that many ordinary stones have become magnetic after being long exposed to the air, in consequence of iron penetrating them. He believes that the native loadstone is made up of ordinary stone and of iron containing many small bodies through which run magnetic channels; that the latter are held together so strongly as to be disintegrated with difficulty, and that they are filled with a subtile matter which circulates incessantly through and around them.
The First Discourse of the Fourth Book treats of Meteors, and at pp. 91–99 of his “Eclaircissements, ...” published in 1710 he gives further reports of his curious observations on magnetic phenomena.
References.—“Journal des Sçavans,” Vol. XXIV for 1696, pp. 649–656.
For particulars of the very celebrated natural philosopher, Christian Huyghens—Hugenius van Zuglichen (1629–1695) above alluded to, consult: the “Vita Hugenii,” prefixed to his “Opera Varia,” published by Van ’Sgravesande in 1724; “Meyer’s Konversations-Lexikon,” Leipzig und Wien, 1895, Vol. IX. pp. 93–94, also the biography, embracing a detailed list of his geometrical, mechanical, astronomical and optical works at pp. 536–538 of the “English Cyclopædia”; Vol. II. of Houzeau et Lancaster, “Bibliog. Générale,” p. 169; “Le Journal des Savants” for May 1834, April 1846, July 1888, April 1896, Feb. 1898, Oct. 1899; “Histoire des Sciences Math. et Phys.,” Maximilien Marie, Paris, 1888, Vol. V. pp. 15–140; “Hist. et Mém. de l’Acad. Roy. des Sc.,” Vol. I. p. 307; Hartsoeker’s biography at pp. 307–308 of the “Engl. Cycl.,” Vol. III, 1867.[49]
A.D. 1707.—J. G. S. (not, as many suppose, Jean George Sulzer) publishes “Curious Speculations during Sleepless Nights” 8vo, Chemnitz, wherein appears the first account of the development, by heat, of electricity in the tourmaline, which latter, it is therein stated, was first brought from Ceylon by the Dutch in 1703. Another report of the above appears in the Mémoires de l’Académie des Sciences of Paris for 1717.
Reference.—Beckmann, Bohn, 1846, Vol. I. pp. 86–98.