[ 47 ] 
Experiment VII. 
* Flake white mixed with egg and milk, crumbled 
all to pieces in the oven, put on the waxed board, as 
in the lad: experiment. 
The bad fuccefs which had attended all the former 
experiments, led me to confider of what ufe the wax 
was in this kind of painting : and it occurred to 
me, that it was only as a varnifh to preferve the co- 
lours from fading. 
In order to try this, 
Experiment VIII. 
I took what the bricklayers call fine duff, or put- 
ty ■f* ; to this I added a fmall quantity of burnt ala- 
bafter, to make it dry : this it foon did in the open 
air ; but before I put on any colours, I dried it gently 
by the fire, led the colours fhould run. When it 
was painted, I warmed it gradually by the fire (to 
prevent the ground from cracking), till it was very 
hot. I then took white wax three parts, white refin 
one part, melted them in an earthen pipkin, and 
with a brufh fpread them all over the painted board, 
and kept it clofe to the fire in a perpendicular 
fituation, that what wax and refin the plaider would 
not abforb might drop off. When it was cold, I 
found the colours were not altered, either from the 
* Flake white is the pureft fort of white lead, 
t Putty is lime flacked, and, while warm, diffolved in water, 
and drained through a fieve. 
heat 
