By the sense of seeing we can form no idea of distances; without aided by the touch, every object would appear to be within our eyes; and an infant, that is as yet a stranger to the sense of feeling, must conceive that every thing it sees exists within itself. The objects only appear to be more or less bulky as they approach to, or recede from the eye; insomuch, that a a fly near the eye will appear larger than an ox at a distance. It is experience alone that can rectify this mistake; and it is by constantly measuring with the hand, and removing from one place to another, that children obtain ideas of distance and magnitude. They have no conception of size but from the extreme rays reflected from the object, of course every thing near appears large, and those at a distance small. The last man in a file of soldiers appears much more diminutive than the one who is nearest to us. We do not, however, perceive this difference, but continue to think him of equal stature; for the number of objects we have seen thus lessened by distance, and found by repeated experience to be of the natural size when we come closer, instantly correct the sense, and therefore we perceive every object nearly in its natural proportion, unless when we observe them in such situations as have not allowed us sufficient experience to correct the illusions of the eye. If, for example, we view men upon the ground, from a lofty tower, or look up to any object upon the top of a steeple, as we have not been in the habit of correcting the sense in that position, they appear to us exceedingly diminished, much more so than if we saw them at the same distance in an horizontal direction.