Dictionary entry

Pyrophorus

Webster's Dictionary 1913

‖Py‐roph″o‐rus (?), n. [NL. See Pyrophorous.] (Old Chem.) Any one of several substances or mixtures which phosphoresce or ignite spontaneously on exposure to air, as a heated mixture of alum, potash, and charcoal, or a mixture of charcoal and finely divided lead.