Note 29 — V.

It is, i think, agreed by all that distance of itself, and immediately cannot be seen. For distance being a line directed end-wise to the eye, it projects only one point in the fund of the eye. Which point remains invariably the same, whether the distance be longer or shorter. — I find it also acknowledged, that the estimate we make of the distance of objects considerably remote, is rather an act of judgment grounded on experience, than of sense. For example: When I perceive a great number of intermediate objects, such as houses, field, rivers, and the like, which I have experienced to take up a considerable space; I thence form a judgment or conclusion, that the object I see beyond them is at a great distance. Again, when an object appears faint and small, which at a near distance I have experienced to make a vigorous and large appearance; I instantly conclude it to be far off. And this, it is evident, is the result of experience; without which, from the faintness and littleness, I should not have inferred any thing concerning the distance of objects.