[3191] From the adjacent town of Chalastra, on the Thermæan Gulf. The site is probably occupied by the modern Kulakia.
[3192] Carbonate of soda is found in the mineral waters of Seltzer and Carlsbad, and in the volcanic springs of Iceland, the Geysers more particularly.
[3193] Ajasson remarks, that from this we may conclude that the fabrication of nitrate of potash, or saltpetre, was in its infancy. It is by no means improbable that the artificial nitrum, here mentioned by Pliny, really was artificial saltpetre, more or less impure; the native nitrum, on the other hand, being, as Beckmann suggests, a general term for impure alkaline mineral salts, in common with native saltpetre. Pliny’s account, however, is confused in the highest degree, and in some passages far from intelligible.
[3194] Of a bituminous nature, probably. See c. 42 of this Book.
[3195] See B. v. c. 40. An alkaline water, Beckmann thinks. See Vol. II, pp. 96-7. Bohn’s Ed.
[3196] He may possibly mean bleaching the material before dyeing.
[3197] See B. xxxvi. c. 65. This certainly goes far towards proving that under the name “nitrum,” alkaline salts were included.
[3198] “Faciunt ex his vasa, necnon frequenter liquatum cum sulphure, coquentes in carbonibus.” This passage Beckmann pronounces to be one of the darkest parts in the history of nitrum. See Vol. II. p. 502. He is of opinion that not improbably the result here obtained would be, liver of sulphur, which when it cools is hard, but soon becomes moist when exposed to the air. Dalechamps, it would appear, explains the whole of this passage as applicable to glazing; but in such case, as Beckmann observes, the nitrum could serve only as a flux. Michaelis suggests that the vessels here mentioned, were cut, not for real use, but merely for ornament, in the same manner as they are still made, occasionally, from rock-salt.
[3199] The mention of nitrum, sulphur, and charcoal, probably the three ingredients of gunpowder, in such close proximity, is somewhat curious.
[3200] “Quæ” seems a preferable reading to “quos.”