Break up orpiment, at first either wrapped up in leather or parchment, or in a little mill for grinding pepper, until it is reduced practically to dust, and then grind it for a long time with water.When the water has dried up, take some of the yolk of a raw egg, and some powder of calcified bones, and grind them in the same way, and then mix them with the ground orpiment until it seems to you well tempered; and temper it with egg white, as you think best. If you take two parts of orpiment, and one of egg yolk and calcified bones, and mix them together, it will be good.