BRONZING  , a

process by which a bronze-like surface is imparted to objects of metal, plaster, wood, &c . On metals a green bronze colour is sometimes produced by the action of such substances as vinegar, dilute nitric acid and sal-ammoniac . An antique appearance may be given to new bronze articles by brushing over the clean bright metal with a solution of sal-ammoniac and salt of sorrel in vinegar, and rubbing the surface dry, the operation being repeated as often as necessary . Another solution for the same purpose is made with sal-ammoniac, cream of tartar, common salt and silver nitrate . With a solution of platinic chloride almost any colour can be produced on copper, iron, brass or new bronze, according to the dilution and the number of applications . Articles of plaster and wood may be bronzed by coating them with size and then covering them with a bronze powder, such as Dutch metal, beaten into fine leaves and powdered . The bronzing of gun-barrels may be effected by the use of a strong solution of antimony trichloride .