(Fr. émail) a semi-transparent or opaque vitrified substance, of the nature of glass, but differing from it by possessing a greater degree of fusibility and opacity. The compound which serves as a basis to most kinds of enamel is formed by the fusion of a pure crystal glass or frit, ground up with a fine calx of lead and tin, in certain proportions; to which is usually added white salt of tartar. The different kinds of enamel are made by the addition of colouring substances, and melting or incorporating the whole by fusion.

For white enamel, Neri (De Arte Vitriar.) directs only manganese to be added to the matter which constitutes the basis; for azure, zaffer mixed with calx of brass; for green, calx of brass with scales of iron, or with crocus martis; for black, zaffer with manganese or with crocus martis, or manganese with tartar; for red, manganese, or calx of copper and crude tartar; for purple, manganese with calx of brass; for yellow, tartar and manganese; and for violet-coloured Enamel, manganese with thrice-calced brass. In making these enamels great nicety is requisite. The general way of making the coloured enamel is this: Powder, sift, and grind all the colours very nicely, and first mix them with one another, and then with the common matter of enamels; next set them in pots in a furnace, and when they are well mixed and incorporated, cast them into water; when dry, set them in a furnace again to melt; and when melted, take a proof of the enamel. If too deep-coloured, add more of the common matter of enamels; and if too pale, add more of the colours.