27 % Panned for Painters . 
Sdly. In that, the field of view does not extend beyond 
thirty degrees, or at most thirty-five degrees, with dis- 
tinctness. 
But in the Camera Lucida as much as seventy or 
eighty degrees might be included in one view. 
NO. 55. 
Method of preparing Pannels for Painters. By Mr . 
S. Grandi.* 
TAKE the bones of sheep’s trotters, break them 
grossly, and boil them in water until cleared from their 
grease, then put them into a crucible, calcine tliem, and 
afterwards grind them to powder. Take some wheat 
en Hour, put it in a pan over a slow fire until it is 
dry, then make it into a thin paste, add an equal quan- 
tity of the powdered bone-ash, and grind the whole 
mass well together : this mixture forms the ground for 
the pannel. 
The pannel having been previously pumiced, some 
of the mixture above-mentioned is rubbed well there- 
on with a pumice-stone, to incorporate it with the pan- 
nel. Another coat of the composition is then applied 
with a brush upon the pannel, and suffered to dry, and 
the surface afterwards rubbed over with sand-paper. 
A thin coat of the composition is then applied with a 
brush, and if a coloured ground is wanted, one or two 
coats of the colour is added, so as to complete the ah 
sorbent ground. 
* Nicholson, vol. 16, p. 316 --The processes of Mr. Grandi being founded 
upon practice, were supported to the Society of Arts, by certificates from our 
most eminent painters ; in consequence of which, and of the exhibition of the 
pannels, the Society awarded him the silver medal and twenty guineas- 
