Coloured crayons may he made by mixing pipeclay with water to form a stiff dough. The material may be made harder by adding a. little soap to the water. For a blue colour, add common ultramarine; for red, use Venetian red; for brown, use limber or vandyke brown •, and for black, use lampblack. After standing two or three days it may be made into balls, rolled into rods between two boards, then cut up into lengths and dried, first in the air and finally in a warm place.