*THE SCIENCE OF ART FORM.*

the different parts are distinguished: the neck from the body of the vessel, and the body of the vessel from the foot. Fig. 2. Two fillets are also very appropriately put where the vessel is largest, and where they seem to convey a sense of increased strength exactly where the pressure is greatest. You will find all the way through the study of ornament that utility, or use, is a fundamental principle which can not be violated without impairing beauty.

Before presenting objects for comparison it may be well to pass in review the elements which compose all objects. Decoration is the application of ornament to form. It therefore presupposes knowledge of both form and ornament, for form must be understood by itself, and ornament by itself, Fig. 3. before the proper ornament may be selected for the given form. The elements of form are length, breadth, and thickness. A mathematical point is conceived to have no dimensions, a mathematical line but one, and a mathematical plane but two. But in actuality there is no tangible object without the third dimension—thickness. Still, where two dimensions are very much more prominent than the third—as, for instance, in a plaque, in the side of a room, in a single elevation of a building, or whenever merely the surface of an object is viewed—the third dimension may be left out of consideration. Lines and the surfaces they bound—that is, length and breadth form which play the chief part in decoration.