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.
ALUMINUM AND ITS TREATMENT
How To Color Aluminum:
Blanching Of Aluminum.
Decolorized Aluminum.
Mat Aluminum.
To Blacken Aluminum.
| II.— | White arsenic | 1 ounce |
|---|---|---|
| Sulphate of iron | 1 ounce | |
| Hydrochloric acid | 12 ounces | |
| Water | 12 ounces |