the art of covering a surface of metal, wood or paper with a fine layer of gold. It was practiced by the ancients, the Egyptians, Persians, Greeks and Romans having shown great skill in it. The ancient mechanical process, the best for many kinds of work, consists in applying a fine gold leaf to a surface which has been treated with a size, which, when partly dry, enables the gold to adhere. Japanner's gilding is performed by covering the surface with a gold dust or powder, instead of gold leaf. The frames of pictures and mirrors, moldings and other articles are gilded by the application of gold leaf, or by the inferior process of German gilding, that is, by tin foil or silver leaf with a yellow varnish above. Books are gilded by covering the edges with some substance to which the gold leaf will stick, and polishing the surface when dry. Metals are often gilded by means of an amalgam of gold and mercury, the mercury being driven off by means of heat after the application. The surface is then varnished In the gilding of iron and steel, gold leaf is sometimes applied after the surface has been well cleaned and heated until it turns a bluish color. The process used in pottery, glass and china consists of applying the gold like paint, after which the articles are baked in an oven of rather low temperature. After cooling, the gold is burnished. There are innumerable special processes for the gilding of particular kinds of ware.