Among Bodies of equal Obscurity, Bigness, Figure, and Distance from the Eye, that will appear the smallest, which is seen on the Whitest Ground, or in the most luminous place: this may be observed in looking at a Tree, stripp'd of its Leaves, and illumined by the Sun, on the side opposite to that, whereon you look; for in that case, those Branches of the Tree, which face the Sun, will be diminished to that Degree, as almost to become invisible: And the same thing will be found in holding out a Pike, or other long Pole, straight between the Eye, and the Sun.

Parallel Bodies, placed upright, and seen in a Fog, will appear larger towards the Top, than near the Bottom: the reason is, that the Foggy Air, being penetrated by the Rays of the Sun, will appear by so much the Whiter, as it is the lower.

Bodies seen at a distance, appear ill proportioned: this happens, because the brighter parts send their Images to the Eye, stronger and more sensible, than those emitted from the obscurer parts; and I once observed, in looking at a Woman, who was dress'd in Mourning, that her Head which was covered with a White Hood, appeared twice as large as her Shoulders which were Black.