That Figure in a History-Piece, which is supposed to be nearest the Eye, ought to have the greatest Relievo. The Reason is evident, since in several Parcels of the same Colour, that must of necessity appear the boldest and most perfect, which has the least Air interposed between it self and the Eye that views it: 'Tis for this Reason that the Shadows which discover the Relievo of Opake Bodies, are always stronger and more obscure, in proportion as they are nearer; the Eye viewing them at a Distance, being confounded by the Air, and unable to distinguish them from the Colours of Objects; whereas, when they are viewed near at Hand, they appear in all their Force, and give each Body a Relievo, in proportion to their deepness and Obscurity.