Note 24 — Chapter IV

This incapacity of the eye must not be confounded with its incapability to comprehend a large portion of lateral space at once. We indeed can see, at any one moment, little more than one point, the objects beside it being confused and indistinct; but we need pay no attention to this in art, because we can see just as little of the picture as we can of the landscape without turning the eye, and hence any slurring or confusing of one part of it, laterally, more than another, is not founded on any truth of nature, but is an expedient of the artist—and often an excellent and desirable one—to make the eye rest where he wishes it. But as the touch expressive of a distant object is as near upon the canvas as that expressive of a near one, both are seen distinctly and with the same focus of the eye, and hence an immediate contradiction of nature results, unless one or other be given with an artificial and increased indistinctness, expressive of the appearance peculiar to the unadapted focus. On the other hand, it must be noted that the greater part of the effect above described is consequent not on variation of focus, but on the different angle at which near objects are seen by each of the two eyes, when both are directed towards the distance.