Natron, the nitre of the ancients, one of the fixed alkalies. See Soda, Chemistry Index.

It is found in great abundance in many parts of Asia, where the natives sweep it up from the surface of the ground, and call it soap earth. The earliest account we have of it is in the Scriptures, where we find that the salt called nitre in those times would ferment with vinegar, and possessed a detergent quality, so that it was used in baths and in washing. Solomon compares the stinging of songs with a heavy heart, to the contrariety of vinegar and nitre: and Jeremiah says, that if the finder wash himself with nitre, his sin is not cleansed off. These are properties that perfectly agree with this salt, but not at all with our saltpetre, which is the nitre of the moderns.

Natterjack, a species of Rana, which see, Reptology Index.