Enamels. "White enamels are composed by melting the oxide of tin with glass, and adding a small quantity of manganese, to increase the brilliancy of the colour. The addition of oxide of lead or antimony produces a yellow enamel; but a more beautiful yellow may be obtained from the oxide of silver. Reds are formed by an intermixture of the oxides of gold and iron, that composed of the former being the most beautiful and permanent. Greens, violets, and blues, are formed from the oxides of copper, cobalt, and iron; and these, when intermixed in different proportions, afford a great variety of intermediate colours.