Chapter LIV contains extracts from Castianus in Geoponic. Græc., Marbodeus and Rhenius, the interpreter of Dionysius.
In 1560 there was established at Naples, by the versatile Giam. della Porta, the first Academy of Sciences—Academia Secretum Naturæ—to which were admitted only those who had contributed to the advancement of medicine or to scientific studies in general (“Science,” December 19, 1902, p. 965).
References.—Libri, “Hist. des Sc. Mathém.” Vol. IV. pp. 108–140, 399–406; Houzeau et Lancaster, Vol. II. p. 229; The Fourth Dissertation of the “Encycl. Brit.,” p. 624; Sarpi, at A.D. 1632; Poggendorff, “Geschichte der Physik,” 1879, pp. 133, 273–274; “Encycl. Brit.,” the article on “Optics”; “Journal des Savants” for September 1841.
A.D. 1575–1624.—Boehm—Böhme—Behmen (Jacob), a mystical German writer, known as the theosophist par excellence, is the author of “Aurora,” etc. (1612), “De Tribus Principiis” (1619) and of many other treatises, which were reprinted under the title of “Theosophia Revelata,” and which contain his many very curious observations concerning astrology, chemistry, theology, philosophy and electricity.
References.—“Notice sur J. Boehm,” La Motte-Fouqué, 1831; “Notes and Queries” for July 28, 1855, p. 63; Ninth “Britan.,” Vol. III. p. 852; J. Ennemoser, “History of Magic,” Vol. II. pp. 297–328.
A.D. 1576.—Norman (Robert), a manufacturer of compass needles at Wapping, is the first who determined the dip or inclination to the earth of the magnetic needle in London, by means of a dipping needle (inclinatorium) of his own making. Five years later (1581) Norman publishes a pamphlet “The Newe Attractive, containing a short discourse of the Magnes or Lodestone, and amongest other his vertues, of a newe discouered secret, and subtill propertie concernyng the Declinyng of the Needle, touched therewith, under the Plaine of the Horizon ...” from which is taken the following:
“Hauing made many and diuers compasses and using alwaies to finish and end them before I touched the needle, I found continuallie that after I had touched the yrons with the stone, that presentlie the north point thereof woulde bend or decline downwards under the horizon in some quantitie; in so much that to the flie of the compass, which was before levell, I was still constrained to put some small piece of ware on the south point and make it equall againe ...” (Weld, “History of the Royal Society,” 1848, Vol. II. p. 432).
In the fourth chapter of his work, Norman describes the mode of making the particular instrument with which he was enabled to establish the first accurate measurement of the dip “which for this citie of London, I finde, by exact obseruations to be about 71 degrees 50 mynutes.”
Whewell thus alludes to several investigations in the same line:
“Other learned men have, in long navigations, observed the differences of magnetic variations, as Thomas Hariot, Robert Hues, Edward Wright, Abraham Kendall, all Englishmen: others have invented magnetic instruments and convenient modes of observation such as are requisite for those who take long voyages, as William Borough, in his book concerning the variation of the compass; William Barlo, in his ‘Supplement’; Robert Norman, in his ‘Newe Attractive.’ This is that Robert Norman (a good seaman and an ingenious artificer) who first discovered the dip of magnetic iron” (“Enc. Metr.,” p. 738; read also paragraph 366 of J. F. W. Herschel’s “Prelim. Disc.,” 1855).