You will every day hear it absurdly said that room decoration should be by flat patterns--by dead colours--by conventional monotonies, and I know not what. Now, just be assured of this--nobody ever yet used conventional art to decorate with, when he could do anything better, and knew that what he did would be safe. Nay, a great painter will always give you the natural art, safe or not. Correggio gets a commission to paint a room on the ground floor of a palace at Parma: any of our people--bred on our fine modern principles--would have covered it with a diaper, or with stripes or flourishes, or mosaic patterns. Not so Correggio: he paints a thick trellis of vine-leaves, with oval openings, and lovely children leaping through them into the room; and lovely children, depend upon it, are rather more desirable decorations than diaper, if you can do them--but they are not quite so easily done. In like manner Tintoret has to paint the whole end of the Council Hall at Venice. An orthodox decorator would have set himself to make the wall look like a wall--Tintoret thinks it would be rather better, if he can manage it, to make it look a little like Paradise;-- stretches his canvas right over the wall, and his clouds right over his canvas; brings the light through his clouds--all blue and clear--zodiac beyond zodiac; rolls away the vaporous flood from under the feet of saints, leaving them at last in infinitudes of light--unorthodox in the last degree, but, on the whole, pleasant. And so in all other cases whatever, the greatest decorative art is wholly unconventional--downright, pure, good painting and sculpture, but always fitted for its place; and subordinated to the purpose it has to serve in that place. II. But if art is to be placed where it is liable to injury--to wear and tear; or to alteration of its form; as, for instance, on domestic utensils, and armour, and weapons, and dress; in which either the ornament will be worn out by the usage of the thing, or will be cast into altered shape by the play of its folds; then it is wrong to put beautiful and perfect art to such uses, and you want forms of inferior art, such as will be by their simplicity less liable to injury; or, by reason of their complexity and continuousness, may show to advantage, however distorted by the folds they are cast into. And thus arise the various forms of inferior decorative art, respecting which the general law is, that the lower the place and office of the thing, the less of natural or perfect form you should have in it; a zigzag or a chequer is thus a better, because a more consistent ornament for a cup or platter than a landscape or portrait is: hence the general definition of the true forms of conventional ornament is, that they consist in the bestowal of as much beauty on the object as shall be consistent with its Material, its Place, and its Office. Let us consider these three modes of consistency a little.