The Artist's Assistant, In the Study and Practice of Mechanical Sciences: Calculated for the Improvement of Genius. Illustrated with Copper-Plates (Birmingham, [ca. 1785])

THE ARTIST'S ASSISTANT. 155

to powder, and mix them. For blue, take powder
of blue, one pound; fal nitre, half a pound; mis
them and grind them ■well together. For carnation,
take red chalk, eight ounces; iron fcales and litharge
of fiiver, of each two ounces; gum arabic, half an
ounce; diffolve in water; grind all together for half
an hour as ftiff as you can; then put it in a glafs and
ftir it well, and let it ftand to lettle fourteen days.
For green, take red lead, one pound; fcales of copper,
one pound; and flint, five pounds: divide them
into three parts ; and add to them as much fal nitre ;
put them into a crucible, and melt them with a ftrcng
fire; and when it is cold, powder it, and grind it on
a porphyry. For goid colour,, take fiiver, an ounce;
antimony half an ounce; melt them in a crucible;
then pound the mafs to powder, and grind it on a
copper-plate; add to it yellow oker, or brick duft
calcined again, fifteen ounces; and grind them well
together with water. For purple, take minum, one
pound; brown {tone, one pound; white flint, five
pounds; divide them into three parts, and add to
them as much fal nitre as one of thefe parts; calcine,
melt, and grind it as you did the green. For red,
take jet, four ounces; litharge of fiiver, two ounces;
red chalk, one ounce; powder them fine, and mix
them. For white take jet, two parts; white flint,
ground on a glafs very fine, one part; mix them.
For yellow take Spanifn brown, ten parts; leaf fiiver,
one part; antimony, half a part; put all into a cru-
cible, and calcine them well.

Thofe beautiful works which were made in the
glafs-houfes were of two kinds. In fome, the colour
was diffufed through the whole fubftance of the
lafs. In others, which were the more commom, the
U 2 colour