INLAYING  , a method of ornamentation, by incrusting or otherwise inserting in one material a substance or substances differing therefrom in

colour or nature . The art is practised in the fabrication of furniture and artistic objects in all varieties of wood, metal, shell, ivory and coloured and hard stone, and in compound substances; and the combinations, styles and varieties of effect are exceedingly numerous . Several special classes of inlaying may be here enumerated and defined, details regarding most of which will be found under their separate headings . In the ornamental treatment of metal surfaces Niello decoration, applied to silver and gold, is an ancient and much-practised species of inlaying . It consists in filling up engraved designs with a composition of silver, copper, lead and sulphur incorporated by heat . The composition is black, and the finished work has the appearance of a drawing in black on a metallic plate . An art, analogous in effect, called bidri, from Bider in the Deccan, is practised in India . In bidri work the ground is an alloy of zinc, with small proportions of copper and lead, in which shallow patterns and devices are traced, and filled up with thin plates of silver . When the surface has been evened and smoothed, the bidri ground is stained a permanent black by a paste the chief ingredients of which are sal-ammoniac and nitre, leaving a pleasing contrast of bright metallic silver in a dead black ground . The inlaying of gold wire in iron or steel is known as DAMASCENING (q.v.) . It has been very largely practised in Persia and India for the ornamentation of arms and armour, being known in the latter country as Kuft work or Kuftgari . In Kashmir, vessels of copper and brass are very effectively inlaid with tin—an art which, like many other decorative arts, appears to have originated in Persia .

In the ornamental inlaying of metal surfaces the

Japanese display the most extraordinary skill and perfection of workmanship . In the inlaying of their fine bronzes they use principally gold and silver, but for large articles and also for common cast hollow ware commoner metals and alloys are employed . In inlaying bronzes they generally hollow out and somewhat undercut the design, into which the ornamenting metal, usually in the form of wire, is laid and hammered over . Frequently the lacquer work of the Japanese is inlaid with mother-of-pearl and other substances, in the same manner as is practised in ornamenting lacquered papier-mache among Western communities . The Japanese also practise the various methods of inlaying referred to under DAMASCENING . The term Mosaic (q.v.) is generally applied to inlaid work in hard stones, marble and glass, but the most important class of mosaics—those which consist of innumerable small separate pieces—do not properly come under the head of inlaying . Inlaid mosaics are those in which coloured designs are inserted in spaces cut in a solid ground or basis, such as the modern Florentine mosaic, which consists of thin veneers of precious coloured stones set in slabs of marble . The Taj Mahal at Agra is an example of inlaid mosaic in white marble, and the art, carried to that city by a French artist, is still practised by native workmen . Pietra dura is a fine variety of inlaid mosaic in which hard and expensive stones —agate, cornelian, amethyst and the like—are used in relief . Certain kinds of enamel might also be included among the varieties of inlaying .