were of opinion that nut-oil-excelled it "in giving brilliancy to pictures, in preserving them better, and in rendering the colours more vivid."158
Lomazzo (a Milanese) says nothing on the subject of vehicles in his principal work, but in his "Idea del Tempio della Pittura,"159 he speaks of grinding the colours "in nut-oil, and spike-oil, and other things," the "and" here evidently means or, and by "other things" we are perhaps to understand other oils, poppy oil, drying oils, &c.
The directions of Raphael Borghini and Vasari160 cannot certainly be considered conclusive as to the practice of the Venetians, but they are very clear on the subject of varnish. These writers may be considered the earliest Italian authorities who have entered much into practical methods. In the few observations on the subject of vehicles in Leonardo da Vinci's treatise, "there is nothing," as M. Merimée observes, "to show that he was in the habit of mixing varnish with his colours." Cennini says but little on the subject of oil-painting; Leon Battista Alberti is theoretical rather than practical, and the published extracts of Lorenzo Ghiberti's MS. chiefly relate to sculpture.
Borghini and Vasari agree in recommending nut-oil in preference to linseed-oil; both recommend adding varnish to the colours in painting on walls in oil, "because the work does not then require to be varnished afterwards," but in the ordinary modes of painting on panel or cloth, the varnish is omitted. Borghini expressly says, that oil alone (senza più) is to be employed; he also recommends a very