BI′DERY

(bē′-). Syn. Vi′dry. An alloy of which the chief seat of the manufacture is the city of Bider′, near Hyderabad, India. It was first brought under the notice of the British public at the International Exhibition of 1851, where many articles made of it were greatly admired for the elegance of their forms, and the gracefulne of their engraved and enchased patterns. Prep. 1. Zinc, 31 parts; copper and lead, of each 2 parts; melted together, with the usual precautions, under a mixture of resin and beeswax, to prevent oxidation. [171] [171] These are very nearly the proportions which Dr Hamilton says he saw used in India. 2. (Dr Heyne.) Copper, 8 parts; lead, 2 parts; tin, 1 part; melted together, as before. For use, the resulting alloy is remelted, and to every 3 parts of it 16 parts of zinc are added. Prop., . Colour between that of pewter and zinc; does not corrode by exposure to air or damp; yields little to the hammer, and can only be broken by extreme violence. It po e es a convenient degree of fusibility, above that of zinc and tin, but much lower than that of copper. For the turner it is usually cast in moulds of baked clay; but otherwise in moulds of iron or other hard metal. The beautiful black colour which the finished articles po e is imparted by dipping them into a solution of sal-ammoniac, saltpetre, sea-salt, and blue vitriol. See Bra , Bronze , Pewter , .