a glass-like glaze of various colors, fused to the surface of gold, silver, copper and other substances. The art of enameling, which is of great antiquity, was practiced by the Assyrians and by the Egyptians, from whom it may have passed into Greece and thence into Rome and its provinces, where various Roman antiquities with enameled ornamentation have been discovered. During the twelfth and fourteenth centuries, the Italians acquired great skill in enameling, and their work became famous in all the countries of Europe. The basis of all kinds of enamel is a perfectly transparent and fusible glass, which is rendered either semitrans-parent or opaque by the mixture of metallic oxides. White enamels are composed by melting the oxide of tin with glass and adding a small quantity of manganese or phosphate of calcium to increase the brilliancy of the color. The addition of the oxide of lead, or antimony, or oxide of silver, produces a yellow enamel. Reds are formed by copper, and by an intermixture of the oxides of gold and iron. Greens, violets and blues are formed from the oxides of copper, cobalt and iron. Enamel is used for glazing the cheaper varieties of pottery and for coating iron vessels for domestic purposes, the protection of the insides of baths, cisterns, boilers and the like. Enameling in colors upon iron is now common, iron plates being thus treated by means of various mixtures, and words and designs of various kinds being permanently fixed upon them by stenciling.