When a dark Body, is painted upon a bright Ground, it appears with a great Relievo, and seems to stand out free from the Painting; the Reason of this is owing to the Curve Surfaces of Bodies, which of necessity growing dark on that side turned from the Light, the difference between the Ground and that side of the Figure, becomes very bold and conspicuous: It must further be observed, that the illuminated part of a Figure ought never to terminate on a Ground brightned by its principal Light; To prevent which, it may be adviseable, between the Ground and the chief Light, to interpose the Extremity of some other Body, more obscure than either the Ground or the Light, respectively.