References.—Hooke’s entire paper in Derham’s “Phil. Exp. and Obs.” for 1726, pp. 142–150; Phil. Trans, for 1684; for his observations on atmospheric electricity consult Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 166; “Journal des Savants” for April 1846; “The Posthumous Works of Robert Hooke,” London, 1705, p. 424; “Revue Scientifique,” Mars 15, 1902, p. 351; for a complete list of all his works, consult Ward’s “Lives of the Gresham Professors”; for description of his telegraph and reference to Amontons, etc., see Phil. Mag., Vol. I. pp. 312–316.
A.D. 1684.—Sturmy’s “Mariner’s Magazine” for this year, of which a copy can be seen in the library of the British Museum, contains an account of the deviation of the compass and its tendency to give misleading directions on account of local attraction.
References.—Chambers’ Journal, Vol. III. No. 60 for Feb. 24, 1855, p. 132, and Vol. XII. No. 300 for Oct. 1, 1859, p. 246; Capt. Sam. Sturmy’s “Magn. Virtues and Tides,” in Phil. Trans., No. 57, p. 726, or “Memoirs of the Roy. Soc.,” Vol. I. p. 134; Phil. Trans., abridgments: by Hutton, Vol. II. p. 560, and by Lowthorp, Vol. II. p. 609; “Journal des Sçavans” for 1683, Vol. XI. pp. 267–293.
A.D. 1684.—In the “Essayes of Natural Experiments made in the Accademia del Cimento” (Englished by Richard Waller), London, 1684, by direction of the Royal Society, there are given, respectively at pp. 53, 123 and 128–132, accounts of the operation of the magnet in vacuo, details of several magnetical experiments and experiments touching amber as well as other electrical bodies.
A.D. 1686.—Maimbourg (Louis), French historian, relates this instance of the employment of the magnet at Chap. VI of the Rev. W. Webster’s translation of his “Histoire de l’Arianisme”: “Whilst Valens (the Roman emperor) was at Antioch ... several pagans of distinction, with the philosophers ... not being able to bear that the empire should continue in the hands of the Christians, consulted privately the demons ... in order to know the destiny of the emperor and who should be his successor.... For this purpose they made a three-footed stool ... upon which, having laid a basin of divers metals, they placed the twenty-four letters of the alphabet around it; then one of these philosophers, who was a magician ... holding in one hand vervain and in the other a ring which hung at the end of a small thread, pronounced ... conjurations ... at which the three-footed stool turning around and the ring moving of itself, and turning from one side to the other over the letters, it caused them to fall upon the table ... which foretold them ... that the Furies were waiting for the emperor at Mimas; ... after which the enchanted ring, turning about again over the letters in order to express the name of him who should succeed the emperor, formed first of all these capital letters, T H E O. After adding a D, to form T H E O D, the ring stopped, and was not seen to move any more, at which one of the assistants cried out ... ‘Theodorus is the person whom the gods appoint for our emperor’” (“History of Christianity,” by the Rev. Henry Hart Milman, London, 1840, Vol. III. p. 120).
Maimbourg’s biography is given at p. 58, Vol. IV. of the “English Encyclopædia.”
A.D. 1692.—Dr. Le Lorrain de Vallemont relates, in “Description de l’Aimant,” etc., which he published at Paris, that, after a very severe wind and rain storm during the month of October 1690, the new steeple of the Church of Notre Dame de Chartres was found to be so seriously injured as to necessitate demolition. It was then observed that the iron cross was covered with a heavy coating of rust, which latter proved to be so highly magnetic that a special report upon it was made in the “Journal des Sçavans” by M. de la Hire, December 3, 1691, at the request of Giovanni Dom. Cassini, and of other members of the French Royal Academy.
References.—“Journal des Sçavans,” Vols. XX, 1692, pp. 357–364 and Vol. XXXV, 1707, pp. 493–494 for additional accounts of the Church of N. Dame de Chartres by M. de la Hire and M. de Vallemont, and for a review of M. de Vallemont’s work, of which latter pp. 4, 30, 66, 74, 89 to 90 merit special attention.
A.D. 1693.—Gregory (David), an eminent mathematician, who, in 1691, had been made Savilian Professor of Astronomy in Oxford mainly through the influence of Newton and Flamsteed, communicates the result of his observations on the laws of magnetic action.
References.—Noad, “Manual of Electricity,” 1859, p. 525, Phil. Trans., Vols. XVIII-XXV; “Biog. Générale,” Vol. XXI. p. 902; Ninth “Britannica,” Vol. XI. p. 182; J. J. Fahie, “A History of El. Tel. to the year 1837,” London, 1884, p. 24.