VI.
The Artist's Materials.
Of chalk and paper (612—617).
612.
To make points [crayons] for colouring dry. Temper with a little wax and do not dry it; which wax you must dissolve with water: so that when the white lead is thus tempered, the water being distilled, may go off in vapour and the wax may remain; you will thus make good crayons; but you must know that the colours must be ground with a hot stone.
613.
Chalk dissolves in wine and in vinegar or in aqua fortis and can be recombined with gum.
614.