a word, to establish the landmarks between the flats of commonplace and the barrens of extravagance.  And, though the personal or individual principles referred to may not with propriety be cited as examples in a general treatise like the present, they are not only not to be overlooked, but are to be regarded by the student as legitimate objects of study.  To the truism, that we can only judge of other minds by a knowledge of our own, we may add its converse as especially true.  In that mysterious tract of the intellect, which we call the Imagination, there would seem to lie hid thousands of unknown forms, of which we are often for years unconscious, until they start up awakened by the footsteps of a stranger.  Hence it is that the greatest geniuses, as presenting a wider field for excitement, are generally found to be the widest likers; not so much from affinity, or because they possess the precise kinds of excellence which they admire, but often from the differences which these very excellences in others, as the exciting cause, awaken in themselves.  Such men may be said to be endowed with a double vision, an inward and an outward; the inward seeing not unfrequently the reverse of what is seen by the outward.  It was this which caused Annibal Caracci to remark, on seeing for the first time a picture by Caravaggio, that he thought a style totally opposite might be made very captivating; and the hint, it is said, sunk deep into and was not lost on Guido, who soon after realized what his master had thus imagined.  Perhaps no one ever caught more from others than Raffaelle.  I do not allude to his “borrowing,” so ingeniously, not soundly, defended by Sir Joshua, but rather to his excitability, (if I may here apply a modern term,)—­that inflammable temperament, which took fire, as it were, from the very friction of the atmosphere.  For there was scarce an excellence, within his knowledge, of his predecessors or contemporaries, which did not in a greater or less degree contribute to the developement of his powers; not as presenting models of imitation, but as shedding new light on his own mind, and opening to view its hidden treasures.  Such to him were the forms of the Antique, of Leonardo da Vinci, and of Michael Angelo, and the breadth and color of Fra Bartolomeo,—­lights that first made him acquainted with himself, not lights that he followed; for he was a follower of none.  To how many others he was indebted for his impulses cannot now be known; but the new impetus he was known to have received from every new excellence has led many to believe, that, had he lived to see the works of Titian, he would have added to his grace, character, and form, and with equal originality, the splendor of color.  “The design of Michael Angelo and the color of Titian,” was the inscription of Tintoretto over the door of his painting-room.  Whether he intended to designate these two artists as his future models matters not; but that he did not follow them is evidenced in his works.  Nor,