HOW BOHEMIAN GLASS IS COLORED.
THE ornamentation of the glass is done partly in connection with the exposure in the furnace, and partly in the finishing shops, where the work is completed by cutting, polishing, tarnishing, etching, painting, and mounting in metal. The glass houses have at their command a very complete color-scale for transparent, opaque, and clouded glasses. But it must not be supposed that a crucible is placed in the furnace for each color, from which glass colored for each ornament is to be made. The colors are worked out by means of what are called pastes, which are kept on hand in sticks or cakes. From pieces of these pastes previously warmed till they are soft, suitable quantities are cut off, laid upon the foundation of white or colored glass, and then spread out by drawing or blowing. By this means only is an economical use of such costly materials as gold and silver compositions possible. Some of the glasses thus treated—gold, copper, and silver glasses—remain still little, or not at all, colored after the melting, shaping, and quick cooling; and do not take on their bright hues till they are reheated. This is the case with the yellow-silver glass, which continues uncolored after the intermelting of the silver salt until it is exposed in the furnace again. Very fine effects are produced by blending or overrunning of the paste-colors provided proper attention is given to the laws of harmony. A blue glass cup is, for example, overlaid with silver glass at its upper edge, and this is drawn down in gradually thinner tones till it fades away at the foot of the vase. Gold and copper-ruby colors are thus combined with green glasses, etc. Another brilliant effect is produced when a still hot bulb of glass is rolled in finely pulverized aventurine glass, and after this is melted, and previous to the shaping of the vessel, is overlaid with a coating of either colored or colorless glass.—Christian at Work.