Henley's Twentieth Century Formulas, Recipes and Processes

by Unknown

ALUM:

Burnt Alum.

II.—Heat ordinary alum (alumina alum) with constant stirring in an iron pan in which it will first melt quietly, and then commence to form blisters. Continue heating until a dry white mass of a loose character remains, which is powdered and kept in well-closed glasses.

ALUM BATH: See Photography.