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])

i34 THE ARTIST'S ASSISTANT.

two or three crayons, to which add a piece of flack-
ed plaifter of Paris about the fize or a pea; mix
theie well together, and form the crayons upon the
chalk. This blue is extremely brilliant, and will
be of great ufe in heightening draperies, &c.

GREENS.

Brilliant greens are produced with great dif-
ficulty, whieh may be procured of thofe who make
it their buhnefs to prepare them, yet the following
compohtions will be found ufeful : Take yellow
oker, and after grinding it with fpirits, mix it with
the powder of Pruffian blue, then temper it with a
knife, and lay the crayons on the chalk, without
rolling them : Befides this ufe king's yellow, mixed
with Pruffian blue, brown oker and Pruffian blue.*
The crayons made of thefe la ft may be rolled,

YELLOWS.

k in G'j yellow

Is the mod ufeful and the moll brilliant, levi-
gated with fpirits of wine, and compofe the differ-
ent teints as before directed. Yellow oker and Na-
ples yellow ground with fpirits will make ufeful
crayons.

ORANGE

Is produced with king's-yellow and Vermillion
ground together with fpirits, and the teints formed
as in other cafes, but no great quantity of them is
required.

BROWNS.

* Roman oker and PrutBah blue mixed in different afoDortions
will be ufeiul.