VOL. LI.] PHILOSOPHICAL TRANSACTIONS. 329 



Abbe Mazeas, translated by Dr. Parsons, and published in the 49th volume of 

 the Philos. Trans, concerning the ancient method of painting with burnt wax, 

 revived by Count Caylus. The Count's method was, First, To rub the cloth 

 or board designed for the picture simply over with bees-wax. Secondly, To lay 

 on the colours mixed with common water; but as the colours will not adhere to 

 the wax, the whole picture was first rubbed over with Spanish whitening,* and 

 then the colours are used. Thirdly, When the picture is dry, it is put near 

 the fire, by which the wax melts, and absorbs all the colours. 



Exper. 1 . — A piece of oak board was rubbed over with bees-wax, first against 

 the grain of the wood, and then with the grain, to fill up all the pores that re- 

 mained after it had been planed, and afterwards was rubbed over with as much 

 dry Spanish white, as could be made to stick on it, this, on being painted (the 

 colours mixed with water only) so clogged the pencil, and mixed so unequally 

 with the ground, that it was impossible to make even an outline, but what was 

 so niuch thicker in one part than another, that it would not bear so much as the 

 name of painting; neither had it any appearance of a picture; however, to pursue 

 the experiment, this was put at a distance from the fire, on the hearth, and the 

 wax melted by slow degrees; but the Spanish white (though laid as smooth as 

 so soft a body would admit, before the colour was laid on) yet on melting the 

 wax into it, was not sufficient to hide the grain of the wood, nor show the co- 

 lours by a proper whiteness of the ground, the wax in rubbing on the board, was 

 unavoidably thicker in some parts than others, and the Spanish white the same: 

 on this he suspected there must be some mistake in the Spanish white, and made 

 the inquiry mentioned in the note below. 



To obviate the inequality of the ground in the first experiment. 



Exper. 1. — A piece of old wainscoat (oak board) ^ of an inch thick, which 

 having been part of an old drawer, was not likely to shrink on being brought 

 near the fire ; this was smoothed with a fish-skin, made quite warm before the 

 fire, and then with a brush dipped in white wax, melted in an earthen pipkin 

 smeared all over, and applied to the fire again, that the wax might be equally 

 thick on all parts of the board, a ground was laid on the waxed board with levi- 

 gated chalk mixed with gum water, viz. gum Arabic dissolved in water; when 

 dry, he painted it with a kind of landscape, and pursuing the method laid down 

 by Count Caylus, brought it gradually to the fire by slow degrees, till it came 

 within I foot of the fire, which made the wax swell and bloat up the picture; 



* Spanish chalk is called by Dr. Parsons, in a note, Spanish white; this is a better kind of whit- 

 ening than the common, and was the only white that had the name of Spanish annexed to it, that 

 he coulJ procure, though he inquired for it at most if not all the colour shops in town, Mr. Dacosta 

 showed him a piece of Spanish chalk in his collection, which seemed more like a cimolia (tobacco 

 pipe clay) and was the reason of his using that in one of the experiments. — Orig. 



VOL. XI, U U • 



