{ 49} In the _Musæum Septalianum_ of Terzagus (Dertonæ, 1664, p. 42) is mentioned a loadstone weighing twelve ounces which would lift sixty pounds of iron.
Sir Isaac Newton had a loadstone weighing 3 grains, which he wore in a ring. It would lift 746 grains.
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 impedim[=e]ta ... 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 Periti[=a] c[=o]plect[=e]s: ab excellentissimo doctore Antonio de F[=a]tis taruisino edita ..._ Lugd., 1530.
[185] PAGE 108, LINE 26. Page 108, line 31. _Cusani in staticis._--See the note to p. 64, line 16.