BRASS 465 



Lyons is made from such rods. Copper vessels may bo superficially converted into 

 brass by boiling them in dilute muriatic acid containing some tartar and zinc 

 amalgam. 



The first step in making brass is to plunge slips of copper into melted zinc till an 

 alloy of somewhat difficult fusion be formed, to raise the heat, and add the remaining 

 proportion of the copper. 



The brass of tho first fusion is broken to pieces, and melted with a fresh quantity 

 of zinc, to obtain the finished brass. Each melting takes from 8 to 9 hours. The 

 metal is now cast into plates, about 40 inches long by 26 broad, and from one-third 

 to half an inch thick. The moulds were formerly slabs of granite mounted in an 

 iron frame. Granite appears to have been preferred as a mould, because it preserves 

 the heat, whilst, by the asperities of its surface, it keeps hold of the clay lute applied 

 to secure the joinings. 



The modern method of making brass, by the direct mixture of the component metals, 

 is largely practised at Birmingham in small square furnaces, built of fire-brick, and 

 measuring from 10 to 12 inches in the side, and about 2 feet in depth. Crucibles of 

 Stourbridge fire-clay, or, rarely, of plumbago, are placed on the iron bars at the 

 bottom of the furnace, and packed round with coke. The ingot copper is first intro- 

 duced into tho crucible, and when this is melted the proper proportion of zinc is 

 cautiously added, the mixture being stirred with an iron poker to ensure union 

 of the metals. As soon as the mixture is thoroughly effected, the crucible is 

 withdrawn, and the molten brass is cast, either into moulds of sand, or into iron 

 ingot moulds, slightly oiled inside, and dusted over with charcoal powder. In the 

 manufacture of the variety of brass called ' Muntz's metal,' an alloy extensively made 

 for sheathing the bottoms of ships, the mixture of metals is generally effected in a 

 reverberatory furnace, instead of in crucibles. See MUNTZ'S METAL. 



The cast plates of brass are usually rolled into sheets. For this purpose they are 

 cut into ribands of various breadths, commonly about 6 inches. The cylinders of the 

 brass rolling mill are generally 46 inches long and 18 inches in diameter. The ribands 

 are first of all passed through the cylinders cold ; but tho brass soon becomes too hard 

 to laminate. It is then annealed in a furnace, and, after cooling, is passed afresh 

 through the rolls. After paring off the chipped edges, the sheets are laminated, two 

 at a time ; and if they are to be made very thin, even 8 plates are to be passed 

 through together. The brass in these operations must be annealed 7 or 8 times before 

 tho sheet arrives at the required thickness. These successive heatings are expensive ; 

 and hence manufacturers have been led to try various plans of economy. The an- 

 nealing furnaces are of two forms, according to the size of the sheets of brass. The 

 smaller are about 12 feet long, with a fire-place at each end, and about 13 inches wide. 

 Tho arch of the furnace has a cylindrical shape, whose axis is parallel to its small 

 side. The hearth is horizontal, and is made of bricks set on edge. In the front of 

 the furnace there is a large door, which is raised by a lever, or chain and counter- 

 weight, and slides in a frame between two cheeks of cast-iron. This furnace has, in 

 general, no chimney, except a vent slightly raised above the door, to prevent the 

 workmen being incommoded by the smoke. Sometimes the arch is perforated with a 

 number of holes. The sheets of brass are placed above each other, but separated by 

 parings, to allow the hot air to circulate among them, the lowest sheet resting upon 

 bars of cast-iron placed lengthwise. 



The larger furnaces are usually 32 feet long, by 6^ feet wide, in the body, and 3 

 feet at the hearth. A grate 13 inches broad extends along each side of the hearth, 

 through its whole length, and is divided from it by a small wall, 2 or 3 inches high. 

 The vault of the furnace has a curvature, and is pierced with 6 or 8 openings, which 

 allow the smoke to pass off into a low bell-chimney above. At each end of the fur- 

 nace is a cast-iron door, which slides up and down in an iron frame, and is poised by 

 a counterweight. On the hearth is a kind of railway, composed of two iron bars, on 

 which the carriage moves with its load of sheets of brass. 



These sheets, being often 24 feet long, could not be easily moved in and out of the 

 furnace ; but as brass laminates well in the cold state, they are all introduced and 

 moved out together. With this view an iron carriage is framed with bars, which rest 

 on four wheels. Upon this carriage, of a length nearly equal to that of the furnace, 

 are laid the sheets, with brass parings between them. The carriage is then raised by 

 a crane to a level with the furnace, and entered upon the grooved bars which lie upon 

 the hearth. That no heat may bo lost, two carriages are provided, the one being 

 ready to put in as the other is taken out ; the furnace is meanwhile uniformly kept 

 hot. This method, however convenient for moving the sheets in and out, wastes a 

 good deal of fuel in heating the iron carriage. 



Tho principal places in which brass is manufactured on a large scale, jn England, 

 are Bristol and Birmingham, and &t Holywell, in North. Walep, 



Voj,. I. H H 



