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. Thi............