Yet let not those other artists of the mind, who work in the airy looms of fancy and wit, imagine that they are weaving their webs, without the direction of a principle, and without a secret habit which they have acquired, and which some have imagined, by its quickness and facility, to be an instinct.  “Habit,” says Reid, “differs from instinct, not in its nature, but in its origin; the last being natural, the first acquired.”  What we are accustomed to do, gives a facility and proneness to do on like occasions; and there may be even an art, unperceived by themselves, in opening and pursuing a scene of pure invention, and even in the happiest turns of wit.  One who had all the experience of such an artist has employed the very terms we have used, of “mechanical” and “habitual.”  “Be assured,” says Goldsmith, “that wit is in some measure mechanical; and that a man long habituated to catch at even its resemblance, will at last be happy enough to possess the substance.  By a long habit of writing he acquires a justness of thinking, and a mastery of manner which holiday writers, even with ten times his genius, may vainly attempt to equal.”  The wit of BUTLER was not extemporaneous, but painfully elaborated from notes which he incessantly accumulated; and the familiar rime of BERNT, the burlesque poet, his existing manuscripts will prove, were produced by perpetual re-touches.  Even in the sublime efforts of imagination, this art of meditation may be practised; and ALFIERI has shown us, that in those energetic tragic dramas which were often produced in a state of enthusiasm, he pursued a regulated process.  “All my tragedies have been composed three times;” and he describes the three stages of conception, development, and versifying.  “After these three operations, I proceed, like other authors, to publish, correct, or amend.”

“All is habit in mankind, even virtue itself!” exclaimed METASTASIO; and we may add, even the meditations of genius.  Some of its boldest conceptions, are indeed fortuitous, starting up and vanishing almost in the perception; like that giant form, sometimes seen amidst the glaciers, afar from the opposite traveller, moving as he moves, stopping as he stops, yet, in a moment lost, and perhaps never more seen, although but his own reflection!  Often in the still obscurity of the night, the ideas, the studies, the whole history of the day, is acted over again.  There are probably few mathematicians who have not dreamed of an interesting problem, observes Professor Dugald Stewart.  In these vivid scenes we are often so completely converted into spectators, that a great poetical contemporary of our country thinks that even his dreams should not pass away unnoticed, and keeps what he calls a register of nocturnals.  TASSO has recorded some of his poetical dreams, which were often disturbed by waking himself in repeating a verse aloud.  “This night I awaked with this verse in my mouth—­

  “E i duo che manda il nero adusto suolo. 
  The two, the dark and burning soil has sent.”