The effects of succession in visual objects explained.

If we can comprehend clearly how things operate upon one of our senses, there can be very little difficulty in conceiving in what manner they affect the rest. To say a great deal therefore upon the corresponding affections of every sense, would tend rather to fatigue us by an useless repetition, than to throw any new light upon the subject by that ample and diffuse manner of treating it; but as in this discourse we chiefly attach ourselves to the sublime, as it affects the eye, we shall consider particularly why a successive disposition of uniform parts in the same right line should be sublime,27 and upon what principle this disposition is enabled to make a comparatively small quantity of matter produce a grander effect, than a much larger quantity disposed in another manner. To avoid the perplexity of general notions; let us set before our eyes, a colonnade of uniform pillars planted in a right line; let us take our stand in such a manner, that the eye may shoot along this colonnade, for it has its best effect in this view. In our present situation it is plain, that the rays from the first round pillar will cause in the eye a vibration of that species; an image of the pillar itself. The pillar immediately succeeding increases it; that which follows renews and enforces the impression; each in its order as it succeeds, repeats impulse after impulse, and stroke after stroke, until the eye, long exercised in one particular way, cannot lose that object immediately, and, being violently roused by this continued agitation, it presents the mind with a grand or sublime conception. But instead of viewing a rank of uniform pillars, let us suppose that they succeed each other, a round and a square one alternately. In this case the vibration caused by the first round pillar perishes as soon as it is formed; and one of quite another sort (the square) directly occupies its place; which however it resigns as quickly to the round one; and thus the eye proceeds, alternately, taking up one image, and laying down another............