we would merely repeat a conviction before expressed, viz. that the preservation of internal brightness, a quality compatible with various methods, has had more to do with the splendour and durability of finely coloured pictures than any vehicle. The observations that follow are therefore merely intended to show how far the older written authorities on this subject agree with the results of modern investigation, without at all assuming that the old methods, if known, need be implicitly followed.
On a careful examination of the earlier pictures, it is said that a resinous substance appears to have been mingled with the colours together with the oil; that the fracture of the indurated pigment is shining, and that the surface resists the ordinary solvents.141 This admixture of resinous solutions or varnishes with the solid is not alluded to, as far as we have seen, by any of the writers on Italian practice, but as the method corresponds with that now prevalent in England, the above hypothesis is not likely to be objected to for the present.
Various local circumstances and relations might seem to warrant the supposition that the Venetian painters used resinous substances. An important branch of commerce between the mountains of Friuli and Venice still consists in the turpentine or fir-resin.142 Similar substances produced from various trees, and known under the common name of balsams,143 were imported from the East through Venice, for general use, before the American balsams144 in some degree superseded them; and a Venetian painter, Marco Boschini, in his description of the Archipelago, does not