[566] Plin. xxxvi. 26, p. 759, and lib. xxxvii. cap. 6, p. 769; he says that artists could make glass vessels nearly similar to those of rock crystal; but he remarks that the latter had nevertheless risen in price. [567] Lib. xxxvii. 24, § 66. [568] Plin. xxxvi. 8, § 13, p. 735. [569] Speculum Lapidum, Parisiis, 1610, 8vo, p. 71. It may not be superfluous here to remark, that this _Alabandicus_ of Pliny must not, as is often the case, be confounded with the precious stone to which he gives the same name, lib. xxxvii. cap. 8. The name properly denotes only a stone from Alabanda in Caria. It occurs, but much corrupted, as the name of a costly stone, in writings of the middle ages. See in Du Cange Alamandinæ, Alavandinæ, Almandinæ; and even in our period so fertile in names, a stone which is sometimes classed with the ruby and sometimes with the garnet, and which is sometimes said to have an affinity to the topaz and hyacinth, is called _Alamandine_ and _Alabandiken_. See Brückman on Precious Stones, who in the second continuation, p. 64, deduces the word from _Allemands_, without recollecting the proper derivation, which he gives himself, i. p. 89 according to Pliny. [570] Canon Medicinæ, lib. ii. tract. 2, cap. 470, de Magnete; and cap. 472, de Magnesia. [571] In his book De Mineralibus, lib. ii. tract. 2, cap. 11. [572] Stirpium et Fossilium Silesiæ Catalogus, Lipsiæ, 1600, 4to, p. 381. PRINCE RUPERT’S DROPS. LACRYMÆ VITREÆ. It is more than probable that these drops, and the singular property which they possess, have been known at the glass-houses since time immemorial. All glass, when suddenly cooled, becomes brittle, and breaks on the least scratch. On this account, as far back as the history of the art can be traced, a cooling furnace was always constructed close to the fusing furnace. A drop of fused glass falling into water[573] might easily have given rise to the invention of these drops; at any rate this might have been the case in rubbing off what is called the navel[574]. It is however certain that they were not known to experimental philosophers till the middle of the seventeenth century. Their withstanding great force applied at the thick end, and even blows; and on the other hand, bursting into the finest dust when the smallest fragment is broken off from the thin end, are properties so peculiar that they must excite the curiosity of philosophers, and induce them to examine these effects, especially at a time when mankind in general exert themselves with the greatest zeal to become better acquainted with the phænomena of natural bodies. On this account they have been noticed in almost every introduction to experimental philosophy. To determine the time then in which they were first made known, seems to be attended with little difficulty; but it still remains doubtful by whom and in what country.