Objects seen through a fog will appear larger than they are in reality, because the aerial perspective does not agree with the linear, viz. the colour does not agree with the magnitude of the object[80]; such a fog being similar to the thickness of air interposed between the eye and the horizon in fine weather. But in this case the fog is near the eye, and though the object be also near, it makes it appear as if it were as far off as the horizon; where a great tower would appear no bigger than a man placed near the eye.
Chap. CCCXXI.—Of those Objects which the Eyes perceive through a Mist or thick Air.
The nearer the air is to water, or to the ground, the thicker it becomes. It is proved by the nineteenth proposition of the second book[81], that bodies rise in proportion to their weight; and it follows, that a light body will rise higher than another which is heavy.
Chap. CCCXXII.—Miscellaneous Observations.
Of different objects equal in magnitude, form, shade, and distance from the eye, those will appear the smaller that are placed on the lighter ground. This is exemplified by observing the sun when seen behind a tree without leaves; all the ramifications seen against that great light are so diminished that they remain almost invisible. The same may be observed of a pole placed between the sun and the eye.
Parallel bodies placed upright, and seen through a fog, will appear larger at top than at bottom. This is proved by the ninth proposition[82], which says, that a fog, or thick air, penetrated by the rays of the sun, will appear whiter the lower they are.
Things seen afar off will appear out of proportion, because the parts which are the lightest will send their image with stronger rays than the parts which are darkest. I have seen a woman dressed in black, with a white veil over her head, which appeared twice as large as her shoulders covered with black.