2Burnt yellow, which is much used in stuccos, is thus made. A lump of good yellow earth is heated red hot; it is then quenched in vinegar, by which it acquires a purple colour.
2Burnt ochre, which is very serviceable in stucco work, is made as follows. A clod of good yellow ochre is heated to a glow on a fire. It is then quenched in vinegar, and the result is a purple colour.