[3201] “Spuma nitri.” An accidental property, Beckmann says, of the same salt that has been previously called “Chalastricum,” “Halmyrax,” “Aphronitrum,” and “Agrion.” In his opinion, “the ancients were acquainted with no other than native nitrum, which they called artificial, only when it required a little more trouble and art to obtain it.”—Hist. Inv. Vol. II. p. 502. Bohn’s Ed.
[3202] “Froth of nitre.” Ajasson identifies this with hydro-carbonate of soda.
[3203] Supposed by Hardouin to be derived from the Greek κόλικας, “round cakes;” owing to the peculiar form of the pieces of rock by which the aphronitrum was produced. The reading, however, is very doubtful. Sillig, from Photius, suggests that it should be “scolecas.”
[3204] One proof, Beckmann thinks, that Soda is meant. See Vol. II. p. 491.
[3205] “Whether Pliny means that the vessels were not burnt, but only baked in the sun, or that before they were filled, they were completely dried in the sun, has been determined by no commentator. To me the latter is probable.”—Beckmann, Hist. Inv. Vol. II. p. 491.
[3206] Beckmann thinks that this mode of adulteration, with lime, is an additional proof that the “nitrum” of our author was only soda. See Vol. II. p. 492.
[3207] That, namely, of the lime. Quick-lime, certainly, would have a pungent taste, in comparison with that of soda, but not in comparison with that of saltpetre.
[3208] Another proof, Beckmann thinks, that it was native soda, impregnated with common salt. Vol. II. p. 492.
[3209] This would hardly apply to soda.
[3210] Probably to promote its rising, as Beckmann observes, Vol. II. p. 496; a circumstance which goes a great way towards proving that “Soda” was included, at least, under the name of “nitrum.” Carbonate of soda is extensively used for this purpose at the present day.