The reason, why Objects at any time appear smaller, than they are in effect, is, that they are seen at a great distance; for in that case, there being a great quantity of Air, interposed between them and the Eye, and that naturally weakening the Lights, of course, the Minute Particles of the Bodies, must be prevented from appearing distinctly to the Eye. Figures of this kind, therefore, must be touch'd very slightly; as if the Painter intended no more than an unfinished Sketch: to do otherwise, wou'd be to go contrary to Nature, whose practice ought ever to be Religiously followed; for as we have already observed, an Object only appears little, on account of its being far removed from the Eye; and a great distance, always supposes a great deal of Air between; as a great deal of Air, ever diminishes the Light, and prevents the Eye from distinguishing the little parts of an Object.