uniform labor.  Whoever has remarked the different effects of some strong exercise, and some little piddling action, will understand why a teasing, fretful employment, which at once wearies and weakens the body, should have nothing great; these sorts of impulses, which are rather teasing than painful, by continually and suddenly altering their tenor and direction, prevent that full tension, that species of uniform labor, which is allied to strong pain, and causes the sublime.  The sum total of things of various kinds, though it should equal the number of the uniform parts composing some one entire object, is not equal in its effect upon the organs of our bodies.  Besides the one already assigned, there is another very strong reason for the difference.  The mind in reality hardly ever can attend diligently to more than one thing at a time; if this thing be little, the effect is little, and a number of other little objects cannot engage the attention; the mind is bounded by the bounds of the object; and what is not attended to, and what does not exist, are much the same in the effect; but the eye or the mind, (for in this case there is no difference,) in great, uniform objects, does not readily arrive at their bounds; it has no rest, whilst it contemplates them; the image is much the same everywhere.  So that everything great by its quantity must necessarily be one, simple and entire.

SECTION XI.

THE ARTIFICIAL INFINITE.

We have observed that a species of greatness arises from the artificial infinite; and that this infinite consists in an uniform succession of great parts:  we observed too, that the same uniform succession had a like power in sounds.  But because the effects of many things are clearer in one of the senses than in another, and that all the senses bear analogy to and illustrate one another, I shall begin with this power in sounds, as the cause of the sublimity from succession is rather more obvious in the sense of hearing.  And I shall here, once for all, observe, that an investigation of the natural and mechanical causes of our passions, besides the curiosity of the subject, gives, if they are discovered, a double strength and lustre to any rules we deliver on such matters.  When the ear receives any simple sound, it is struck by a single pulse of the air which makes the ear-drum and the other membranous parts vibrate according to the nature and species of the stroke.  If the stroke be strong, the organ of hearing suffers a considerable degree of tension.  If the stroke be repeated pretty soon after, the repetition causes an expectation of another stroke.  And it must be observed, that expectation itself causes a tension.  This is apparent in many animals, who, when they prepare for hearing any sound, rouse themselves, and prick up their ears; so that here the effect of the sounds is considerably augmented by a new auxiliary, the expectation.  But though after a number of strokes,