Decorative processes in metal-work date back to very remote times, and the early tools and objects in metal in our museums show how decorative effects can be produced by very simple means. The early forms of decoration consisted of series of lines arranged to form a definite pattern, often of a geometric character. Dots of various sizes punched either from the front or back were often arranged in the same manner, roughly shaped bumps were hammered up from the back in thin metal and then these shaped bumps were outlined on the front with engraved lines which gave the form required. The bronze-plated doors of Shalmaneser II, now in the British Museum, and made about 859-824 B.C., are decorated in this manner. A very early example of decoration by means of engraved lines is the bronze pin shown in Fig. 14, p. 158, and the bronze shield Fig. 14 on the same page shows also an early specimen decorated by bosses. The silver plate or dish in Fig. 5, Ch. viii, from the Victoria and Albert Museum, of a much later date, shows alternate decoration by a similar process, and the wider range of sizes makes it most effective. The gold petrel illustrated in Fig. 14, now in the gold room of the British Museum, is another example of the possibilities of decoration by means of different-sized punches of various shapes, and the finger plates shown in Ch. vii, Fig. 4, show how an arrangement of bosses and engraved lines can be made effective and suitable for modern requirements. Further applications of these simple processes are illustrated in Ch. vii, Fig. 5.

Engraving is cutting a design with a graver or burin, but it can be done with other tools which produce a similar effect. In some kinds of engraving the tool is fixed into a handle of wood and used by hand, but in other kinds of work it is used like a chisel and hit with a hammer. In memorial tablets the design is cut by the latter method, and different-shaped chisels are used, depending on the design and shape of the cutting. In some instances coloured wax is laid in the grooves or channels so formed. The greater part of old work, however, was cut with chisels or gravers leaving vee section lines of various widths. Some modern work is done with a machine called a Router, which cuts away the groundwork leaving the letters or ornament in relief.

Fig. 14.-Ancient metalwork in the British Museum.