But though right and wrong are thus found broadly opposed in works severally so mean and so mighty as the roof of Milan and that of the Sistine, there are works neither so great nor so mean, in which the limits of right are vaguely defined, and will need some care to determine; care only, however, to apply accurately the broad principle with which we set out, that no form nor material is to be _deceptively_ represented. XV. Evidently, then, painting, confessedly such, is no deception: it does not assert any material whatever. Whether it be on wood or on stone, or, as will naturally be supposed, on plaster, does not matter. Whatever the material, good painting makes it more precious; nor can it ever be said to deceive respecting the ground of which it gives us no information. To cover brick with plaster, and this plaster with fresco, is, therefore, perfectly legitimate; and as desirable a mode of decoration as it is constant in the great periods. Verona and Venice are now seen deprived of more than half their former splendor; it depended far more on their frescoes than their marbles. The plaster, in this case, is to be considered as the gesso ground on panel or canvas. But to cover brick with cement, and to divide this cement with joints that it may look like stone, is to tell a falsehood; and is just as contemptible a procedure as the other is noble. It being lawful to paint then, is it lawful to paint everything? So long as the painting is confessed--yes; but if, even in the slightest degree, the sense of it be lost, and the thing painted be supposed real--no. Let us take a few instances. In the Campo Santo at Pisa, each fresco is surrounded with a border composed of flat colored patterns of great elegance--no part of it in attempted relief. The certainty of flat surface being thus secured, the figures, though the size of life, do not deceive, and the artist thenceforward is at liberty to put forth his whole power, and to lead us through fields and groves, and depths of pleasant landscape, and to soothe us with the sweet clearness of far off sky, and yet never lose the severity of his primal purpose of architectural decoration. In the Camera di Correggio of San Lodovico at Parma, the trellises of vine shadow the walls, as if with an actual arbor; and the troops of children, peeping through the oval openings, luscious in color and faint in light, may well be expected every instant to break through, or hide behind the covert. The grace of their attitudes, and the evident greatness of the whole work, mark that it is painting, and barely redeem it from the charge of falsehood; but even so saved, it is utterly unworthy to take a place among noble or legitimate architectural decoration.