The expression is the great difficulty in history or portrait-painting, and yet it is the great clue to both. It renders forms doubly impressive from the interest and signification attached to them, and at the same time renders the imitation of them critically nice, by making any departure from the line of truth doubly sensible. Mr. Coleridge used to say, that what gave the romantic and mysterious interest to Salvator’s landscapes was their containing some implicit analogy to human or other living forms. His rocks had a latent resemblance to the outline of a human face; his trees had the distorted jagged shape of a satyr’s horns and grotesque features. I do not think this is the case; but it may serve to supply us with an illustration of the present question. Suppose a given outline to represent a human face, but to be so disguised by circumstances and little interruptions as to be mistaken for a projecting fragment of a rock in a natural scenery. As long as we conceive of this outline merely as a representation of a rock or other inanimate substance, any copy of it, however rude, will seem the same and as good as the original. Now let the disguise be removed and the general resemblance to a human face pointed out, and what before seemed perfect, will be found to be deficient in the most essential features. Let it be further understood to be a profile of a particular face that we know, and all likeness will vanish from the want of the individual expression, which can only be given by being felt. That is, the imitation of external and visible form is only correct or nearly perfect, when the information of the eye and the direction of the hand are aided and confirmed by the previous knowledge and actual feeling of character in the object represented. The more there is of character and feeling in any object, and the greater sympathy there is with it in the mind of the artist, the closer will be the affinity between the imitation and the thing imitated; as the more there is of character and expression in the object without a proportionable sympathy with it in the imitator, the more obvious will this defect and the imperfection of the copy become. That is, expression is the great test and measure of a genius for painting, and the fine arts. The mere imitation of _still-life_, however perfect, can never furnish proofs of the highest skill or talent; for there is an inner sense, a deeper intuition into nature that is never unfolded by merely mechanical objects, and which, if it were called out by a new soul being suddenly infused into an inanimate substance, would make the former unconscious representation appear crude and vapid. The eye is sharpened and the hand made more delicate in its tact, ‘While by the power Of harmony, and the deep power of joy, We see into the life of things.’