2The white lead is roasted in a furnace, and, by the action of the fire, becomes red lead. This invention was the result of observation in the case of an accidental fire; and, by the process, a much better material is obtained than that which is procured from mines.
2White lead on being heated in an oven changes its colour on the fire, and becomes sandarach. This was discovered as the result of an accidental fire. It is much more serviceable than the natural sandarach dug up in mines.