On this kind of beauty, mistaking it for the only one, Hogarth founded his peculiar doctrine. "He adopts two lines, on which, according to him, the beauty of figure principally depends. One is the waving line, or a curve bending gently in opposite directions. This he calls the line of beauty; and he shows how often it is found in flowers, shells, and various works of nature; while it is common also in the figures designed by painters and sculptors, for the purpose of decoration. The other line, which he calls the line of grace, is the former waving line, twisted round some solid body. Twisted pillars and twisted horns exhibit it. In all the instances which he mentions, variety plainly appears to be so important an element of this kind of beauty, that he states a portion of the truth, when he defines the art of drawing pleasing forms to be the art of varying well; for the curve line, so much the favorite of painters, derives much of its beauty from its perpetual bending and variation from the stiff regularity of the straight line." It is evident, however, that in this, he mistakes one kind of beauty for all. Of architecture, considered as a fine art, much of the beauty depends on the imitation of vegetable forms. Employing materials which require the best characteristics of the first kind of beauty, it, in its choicest and ornamented parts, imitates both the rigid trunks, and the delicate and bending forms of plants. Its columns, tapering upward, are copied from the trunks of trees; and their decorations are suited with consummate art to their dimensions, and the weight they support. The simple Doric has little ornament; the elegant Ionic has more; the light Corinthian has most. On the subject of these finely-calculated ornaments, some observations have struck me, which I have not seen mentioned elsewhere. The Doric presents only columns, without any other ornament than that of which their mere form admits. The Ionic expresses increased lightness, by the interposition of its volute, as if the superincumbent weight had but gently pressed a soft solid into a scroll. The Corinthian expresses the utmost lightness, by forming its capitals of foliage, as if the weight above them could not crush even a leaf. The Composite expresses gayety, by adding flowers to the foliage. It is from imperfect views of this, that the meaning and effect of caryatides have been mistaken: instead of being oppressed by weight, they seem, when well employed, to have no weight to support. In nearly all internal architectural decorations, it is the delicate, bending, varied, and contrasted vegetable forms which are imitated.