BRONZING; BRONZE POWDER. Muc ingenuity is displayed in imitating the color of ancient bronzes—both the greenish an the rich golden tints. Metals, wood, an plaster, are all subject to surface-process( having this object in view.
Captain Pidding states that the Chine( exercise the art of bronzing in a very superic manner. After having rubbed the vase ( other ornament with coal-ashes and vinega they dry it in the sun, and then coat it with composition of which the following are the it gredients—two parts of verdigris, two of cii nabar, two of sal ammoniac, two of the bee and liver of duck, and five of pounded alun —moistened to the consistency of a When the article is thus prepared, it is passe through the fire, and washed when cold gain it is coated with the composition, agai _Tired, and again washed ; and so on for sever: times in succession.
Becquerel introduced to the notice of th Academie des Sciences, a few years ego, method of bronzing, in which a thin layer bronze is applied to the surface of any articl of iron, steel, lead, zinc, tin, or other meta It is effected by precipitation from a solutioi through the agency of a galvanic battery i the usual manner of electro-metallurgy ; bt the difficulty surmounted consists in the die covery of a proper solution. The solutio
described by Becquerel consists of carbonat of potash, chloride of copper, sulphate of zinc and nitrate of ammonia ; with a plate of bras or bronze as a positive decomposing plate.
A process of bronzing on paper is now f•E quently adopted for ornamental purpose: Thin plates of copper, or of copper alloye with some other metal, are beaten out int thin leaves, and these leaves are ground c worked to powder. A pattern is printed a the surface of paper with an adhesive an rapidly-drying varnish ; and just before thi varnish is dry, the bronze powder is rubbe on with a piece of soft cotton, whereby a ME tallic lustre is produced, varying in its tin from a bright gold to a deep red colour, a( cording to the metallic constituents of th bronze powder. Sheets of paper, thus bronze after having been glazed and printed,in variou colours, now form the highly adorned covet ings for albums and many other kinds c books,