In design he exhausted not all that depth of knowledge, so conspicuous in Bonarruoti; but it was at once so great and so select, that the Caracci themselves adopted it for their model. I am aware, that Algarotti considered him to be somewhat incorrect in the expression of his contours; while Mengs, on the other hand, defends him very warmly from such a charge. Truly, there does not appear the same variety in his lines as is to be found in Raffaello and the ancients, inasmuch as he purposely avoided angles and rectilinear lines, preserving, as much as lay in his power, an undulating sweep of outline, sometimes convex and sometimes concave; while it is maintained, that his grace results, in a great measure, from this practice: so that Mengs in uncertainty appears at one time to commend, and at another to excuse him for it. He is lavish of his praises on the design of his draperies, on whose masses Coreggio bestowed more attention than on the particular folds; he being the first who succeeded in making drapery a part of the composition, as well by force of contrast as by its direction; thus opening a new path which might render it conspicuous in large works. In particular, his youthful and infantile heads are greatly celebrated; the faces beaming with so much nature and simplicity, as to enchant, and to compel us, as it were, to smile as they smile.[22] Each separate figure may be pronounced original, from the infinite variety of foreshortenings he has introduced; there is scarcely a single head that is not seen from a point of view either above or below; not a hand, not a whole figure, whose attitude is not full of an ease and grace of motion, beyond example. By his practice of foreshortening figures upon ceilings, which was avoided by Raffaello, he overcame many difficulties still remaining to be vanquished after the time of Mantegna, and in this branch of perspective is justly entitled to the merit of having rendered it complete. Footnote 22: This is an expression of Annibal Caracci. Elsewhere he observes: "This kind of delicacy and purity, which is rather truth itself than verisimilitude, pleases me greatly. It is neither artificial nor forced, but quite natural."