Aphronitre, or aphronitrum, is a kind of nitre, mentioned in ancient texts. It was supposed to be the foam or froth of a liquid, emerging to the top. Naturalists have taken the ancient aphronitre to have been a native saltpetre.
References
References
- This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "Aphronitre". Cyclopædia, or an Universal Dictionary of Arts and Sciences (1st ed.). James and John Knapton, et al.
- digicoll.library.wisc.edu