Thomson's British Annual, 1837, p. 354, gives the following reference: "In the Records of General Science, vol. iii., p. 272, there is an interesting description of a very powerful magnet which was sent from Virginia in 1776 by the celebrated Dr. Franklin to Professor Anderson, of Glasgow. It is now in the possession of Mr. Crichton. It weighs 2½ grains, and is capable of supporting a load of 783 grains, which is equivalent to 313 times its own weight."
[180] Page 99, line 10. Page 99, line 11. Manifestum est.—In this, as in many other passages, Gilbert uses this expression in the sense that it is demonstrable rather than meaning that it is obvious: for the fact here described is one that is not at all self-evident, but one which would become plain when the experiment had been tried. For other instances of this use of manifestum see pages [144], line 20; [158], line 19; [162], line 10.
[181] Page 100, line 20. Page 100, line 24. si per impedimēta ... pervenire possunt.—All editions agree in this reading, but the sense undoubtedly requires non possint. Compare p. 91, line 21.
[182] Page 102, line 4. Page 102, line 4. capite 4.—This is a misprint for capite 40, and is retained in the later editions. In the quotation from Baptista Porta, where the English version of 1658 is adhæred to, the words "& deturbat eam" have been omitted by the translator.
[183] Page 107, line 16. Page 107, line 18. Cardanus scribit.—The alleged perpetual motion machine is mentioned in De rerum varietate, lib. 9, cap. xlviii. (Basil., 1581, p. 641). See also the [Note] to p. [223]. For Peregrinus and for Taisnier, see the [note] to p. [5], lines 8 and 12.
[184] Page 107, line 19. Page 107, line 21. Antonij de Fantis.—His work is: Tabula generalis scotice subtilitatis octo Sectionibus vniuersam Doctoris Subtilis Peritiā cōplectēs: ab excellentissimo doctore Antonio de Fātis taruisino edita ... Lugd., 1530.
[185] Page 108, line 26. Page 108, line 31. Cusani in staticis.—See the [note] to p. [64], line 16.
[186] Page 108, line 33. Page 108, line 41. Languidi ... tardiùs acquiescunt.—The editions of 1628 and 1633 omit these seven words.
[187] Page 109, line 11. Page 109, line 13. halinitro.—Either native carbonate of soda or native carbonate of potash might be meant, but not saltpetre. Scaliger, in his De Subtilitate ad Cardanum (Lutet., 1557, p. 164), Exercitatio CIII., 15, under the title, Nitrum non est Salpetræ, says: "More tuo te, tuaque confundis. Salpetræ inter salis fossilis ponis hîc. Mox Halinitrum inter salis, & nitri naturam, speciem obtinere."
"Sal nitrum is salt which is boiled out of the earth, especially fat earth, as in stables, or any place of excrements." (A Chymicall Dictionary explaining Hard Places and Words met withall in the Writings of Paracelsus ..., Lond., 1650.)