We not only _see_, but _feel_ expression, by the help of the finest of all our senses, the sense of pleasure and pain. He then is the greatest painter who can put the greatest quantity of expression into his works, for this is the nicest and most subtle object of imitation; it is that in which any defect is soonest visible, which must be able to stand the severest scrutiny, and where the power of avoiding errors, extravagance, or tameness can only be supplied by the fund of moral feeling, the strength or delicacy of the artist’s sympathy with the ideal object of his imitation. To see or imitate any given sensible object is one thing, the effect of attention and practice; but to give expression to a face is to collect its meaning from a thousand other sources, is to bring into play the observation and feeling of one’s whole life, or an infinity of knowledge bearing upon a single object in different degrees and manners, and implying a loftiness and refinement of character proportioned to the loftiness and refinement of expression delineated. Expression is of all things the least to be mistaken, and the most evanescent in its manifestations. Pope’s lines on the character of women may be addressed to the painter who undertakes to embody it. ‘Come then, the colours and the ground prepare, Dip in the rainbow, trick it off in air; Chuse a firm cloud, before it falls, and in it Catch, ere it change, the Cynthia of the minute.’ It is a maxim among painters that no one can paint more than his own character, or more than he himself understands or can enter into. Nay, even in copying a head, we have some difficulty in making the features unlike our own. A person with a low forehead or a short chin puts a constraint on himself in painting a high forehead or a long chin. So much has sympathy to do with what is supposed to be a mere act of servile imitation!—To pursue this argument one step farther. People sometimes wonder what difficulty there can be in painting, and ask what you have to do but to set down what you see? This is true, but the difficulty is to see what is before you. This is at least as difficult as to learn any trade or language. We imagine that we see the whole of nature, because we are aware of no more than we see of it. We also suppose that any given object, a head, a hand, is one thing, because we see it at once, and call it by one name. But how little we see or know, even of the most familiar face, beyond a vague abstraction, will be evident to every one who tries to recollect distinctly all its component parts, or to draw the most rude outline of it for the first time; or who considers the variety of surface, the numberless lights and shades, the tints of the skin, every particle and pore of which varies, the forms and markings of the features, the combined expression, and all these caught (as far as common use is concerned) by a random glance, and communicated by a passing word.