we expect still more, not being able to ascertain the exact time of their arrival, when they arrive, they produce a sort of surprise, which increases this tension yet further.  For I have observed, that when at any time I have waited very earnestly for some sound, that returned at intervals, (as the successive firing of cannon,) though I fully expected the return of the sound, when it came it always made me start a little; the ear-drum suffered a convulsion, and the whole body consented with it.  The tension of the part thus increasing at every blow, by the united forces of the stroke itself, the expectation and the surprise, it is worked up to such a pitch as to be capable of the sublime; it is brought just to the verge of pain.  Even when the cause has ceased, the organs of hearing being often successively struck in a similar manner, continue to vibrate in that manner for some time longer; this is an additional help to the greatness of the effect.

SECTION XII.

THE VIBRATIONS MUST BE SIMILAR.

But if the vibration be not similar at every impression, it can never be carried beyond the number of actual impressions; for, move any body as a pendulum, in one way, and it will continue to oscillate in an arch of the same circle, until the known causes make it rest; but if, after first putting it in motion in one direction, you push it into another, it can never reassume the first direction; because it can never move itself, and consequently it can have but the effect of that last motion; whereas, if in the same direction you act upon it several times, it will describe a greater arch, and move a longer time.

SECTION XIII.

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,[36] 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