ON THE NATURE OF DRYING OILS. 267 



I mowed Tome of this to a gentleman who was converfant Additional pro. 

 in fuch fubje&s. He told me that, when at Venice, he fie- Venetians ufcd* 

 quently rubbed pictures violently with his handkerchief, to it. 

 try if he could difcover what they were painted with ; and 

 when (6 rubbed, they fmelt exactly like what I then pro- 

 duced to him. 



As I had previoufly perfected what I thought to be a fupe- This laft com- 

 rior vehicle, with which this could not vie in hardnefs and ^^uHble thta 

 durability, I did not profecute my experiments with this any the former, 

 farther ; but as it unites rapidly with copal, and poueflfes all 

 its vifiblc properties, I may be permitted to conjecture that it 

 would have fimilar effe&s when mixed with colours : and if 

 there was any fecond, inferior, and common vehicle, fimilar 

 in its vifible properties to the laft, and (b much within the 

 reach of the moil ordinary painters, as to give their works one 

 common mark with thofe of the firft artifts, it would be diffi- 

 cult to point out a fubftance more likely to afford it than this 

 which mult have been common in their own country, fince 

 its name is ftill attached to fubftances of the fame clafs 

 throughout Europe, though its real properties are now but 

 little known. 



If this was the bafis of the common Venetian vehicle, it It might be ufed 



might have been ufed with or without oil. If the latter, the with oil ***** 



° out. 



works of the common Venetian painters muft have been mere 



varnilh painting : if the former, it muft have been compounded 

 with the oil, according to the principles I have already ex- 

 plained. I am inclined towards the latter opinion, from 

 having heard an obfervation attributed to Bombelli, a cele- 

 brated Venetian painter, who faid, " Tfutt he wijhed his pic~ 

 lures to dry as f aft as poffible, that the oil in them might not rife 

 tothefurface, and turn yellow." 



. To this conjecture it may be objected that turpentines and 

 compounds from them do not dry well. I am not prepared to 

 anfwer this objection, as I have made no experiments relative 

 to it; but it certainly is not conclufive, as fuch compounds 

 may not dry well in this country, though they may in the 

 warm climate of Italy. 



In the Maniere d'imprimer les Tableaux •, publifhed by Le Vamifli of Le 

 Blond at Paris, 1740, is a recipe for the varniih he ufed on BIond * 

 th$ coloured prints executed by him, in this country, before 



he 



