Note 63 — Chapter XXIII
Reading edition
Nitre, or "nitrate," is a native nitrate of potash, or nitrate of soda. The latter, commonly called cubic nitre or Chile saltpetre, is the kind occurring in Chile. Inasmuch as it is very soluble, a plentiful rainfall would soon leach it from the ground and carry it to the sea. The nitrate is thought to be of vegetable origin.