Pannels for Painters . 
When it is necessary to paint upon a pannel thus 
prepared, it must be rubbed over with a coat of raw lin- 
seed or poppy-oil, as drying oil would destroy the ab- 
sorbent quality of the ground; and the painter’s colours 
should be mixed up with the purified oil hereafter men- 
tioned. 
Canvass grounds are prepared, by giving them a thin 
coat of the composition, afterwards drying and pumicing 
them, then giving them a second coat, and, lastly, a coat 
of colouring matter along with the composition. 
The grounds thus prepared do not crack ; they may be 
painted on a very short time after being laid, and from 
their absorbent quality, allow the business to be proceed- 
ed upon with greater facility and better effect than with 
those prepared in the usual mode. 
Method of purifying Oil for Painting . 
Make some of the bone-ashes into a paste with a little 
water, so as to form a mass or ball ; put this ball into the 
fire, and make it red hot ; then immerse it for an hour, in 
a quantity of raw linseed oil, sufficient to cover it : when 
cold, pour the oil into bottles, add to it a little bone-ash, 
let it stand to settle, and in a day it will be clear and fit 
for use. 
White Colour is made by calcining the bone of sheep’s 
trotters in a clear open fire, till they become a perfect 
white^ which will never change. 
Brown Colour is made from bones in a similar man- 
ner, only calcining them in a crucible instead of an open 
fire* 
Yellow Colour , or Masticot. Take a piece of soft 
brick, of a yellowish colour, and burn it in the fire ; then 
take for every pound of brick, a quarter of a pound of 
flake white, grind them together and calcine them ; after- 
Vol. II. l 1 
