UCCELLO'S ENTHUSIASM.
"Paolo Uccello employed himself perpetually and without any intermission," says Vasari, "in the consideration of the most difficult questions connected with art, insomuch that he brought the method of preparing the plans and elevations of buildings, by the study of linear perspective, to perfection. From the ground plan to the cornice, and summit of the roof, he reduced all to strict rules, by the convergence of intersecting lines, which he diminished towards the centre, after having fixed the point of view higher or lower, as seemed good to him; he labored, in short, so earnestly in these difficult matters that he found means, and fixed rules, for making his figures really to seem standing on the plane whereon they were placed; not only showing how in order manifestly to draw back or retire, they must gradually be diminished, but also giving the precise manner and degree required for this, which had previously been done by chance, or effected at the discretion of the artist, as he best could. He also discovered the method of turning the arches and cross-vaulting of ceilings, taught how floors are to be foreshortened by the convergence of the beams; showed how the artist must proceed to represent the columns bending round the sharp corners of a building, so that when drawn in perspective, they efface the angle and cause it to seem level. To pore over all these matters, Paolo would remain alone, almost like a hermit, shut up in his house for weeks and months without suffering himself to be approached."