Note (73) — BOOK II. (continued 2)

73. Nitre.) So much has been said by modern authors concerning the nitre of the ancients, that it would be impertinent to give a particular account of it here. The greatest plenty was produced in Egypt, in the lands which the Nile had overflowed. Most naturalists believe it to have been a native alkaline salt. Pliny says, it was adulterated in Egypt by lime, but that trick was easily discovered by putting it in water, when the true nitre would dissolve, and the lime not. Plin. lib. xxxi. cap. 10. where a long account of it may be seen.