The invention of Mr. Nichol of a method of destroying one of the rays of a polarized beam in a crystal of calcareous spar, has however in later times entirely replaced the use of the tourmaline in optical science, the colour of the tourmaline being a disadvantage which is entirely removed in the use of Nichol’s prism[223].] FOOTNOTES [210] Theophrast. De Lapidibus, edit. Heinsii, fol. p. 395, and Plin. lib. xxxvii. c. 3, and lib. viii. c. 38. [211] Epiphanius De XII Gemmis. [212] J. de Laet De Gemmis. 1647, 8vo, p. 155. [213] Phil. Trans. vol. li. 1. p. 394. [214] Recueil de Mem. sur la Tourmaline, par Æpinus. Petersb. 1762, 8vo, p. 122. [215] Gemm. et Lapidum Historia. 1647, 8vo, p. 441, 450. [216] Plin. lib. xxxvii. c. 7. [217] India produces also the lychnites, the splendour of which is heightened when seen by the light of lamps; and on this account it has been so called by the Greeks. It is of two colours; either a bright purple, or a clear red, and if pure is thoroughly transparent. When heated by the rays of the sun, or by friction, it attracts chaff and shavings of paper. It obstinately resists the art of the engraver.--Solinus, c. lii. p. 59. Traj. 1689, fol. [218] “Hager albuzedi is a red stone, but less so than the hyacinth, the redness of which is more agreeable to the eye, as there is no obscurity in it. The mines where this stone is found are in the East. When taken from the mine it is opake; but when divested of its outer coat by a lapidary, its goodness is discovered, and it becomes transparent. When this stone has been strongly rubbed against the hair of the head it attracts chaff, as the magnet does iron.”--Serapionis Lib. de simplicibus medicinis. Argent. 1531, fol. p. 263. [219] Curiöse Speculationes bey Schlaf-losen Nächten, 8vo, Chemnitz, 1707. The author’s name appears to be expressed by the initials I. G. S. This work consists of forty-eight dialogues, each twelve of which have a distinct title. [220] Frankf. 1713, 8vo.