COPPER 



bean shot. When the melted copper falls into cold water perpetually renewed, the 

 granulations are irregular, thin, and ramified ; constituting feathered shot. The bean 

 shot is the form employed in brass making. 



Copper is also made into small ingots, about six ounces in weight. These are in- 

 tended for exportation to the East Indies, and are known in commerce by the name 

 of Japan copper. Whenever these little pieces are solidified, they are thrown, while 

 hot, into cold water. This immersion slightly oxidises the surface of the copper, and 

 gives it a fine red colour. 



Lastly, copper is often reduced into sheets, for the sheathing of ships, and many 

 other purposes. 



The cylinders for rolling copper into sheets are usually 3 feet long and 15 inches 

 in diameter. They are uniform. The upper roller may be approached to the xinclcr 

 one by a screw, so that the cylinders are brought closer in proportion as the sheet is 

 made thinner. 



The ingots of copper are laid upon the sole of a reverberatory furnace to be heated ; 

 they are placed alongside each other, and are formed into piles in a cross-like arrange- 

 ment, so that the hot air may pass freely round them all. The door of the furnace is 

 shut, and the workman looks in through a peep-hole from time to time, to see if they 

 have taken the requisite temperature ; namely, a dull red. The copper is now passed 

 between the cylinders ; but although this metal is very malleable, the ingots cannot 

 be reduced to sheets without being several times heated ; because the copper cools, 

 and acquires, by compression, a texture which stops the further progress of lami- 

 nation. See ANNEALING. 



These successive heatings are given in the furnace above indicated ; though, when 

 the sheets are to have a very great size, furnaces somewhat different are had recourse 

 to. They are from 12 to 15 feet long and 5 feet wide. See BRASS. 



The copper, by successive heating and lamination, gets covered with a coating of 

 oxide, which is removed by steeping the sheets for a few days in a pit filled with 

 urine ; they are then put upon the sole of the heating furnace. Ammonia is formed, 

 which acts on the copper oxide, and lays bare the metallic surface. The sheets are 

 next rubbed with a piece of wood, then plunged, while still hot, into water, to make 

 the oxide scale off; and are lastly passed cold through the rolling press to smooth 

 them. They are now cut square, and packed up for home sale or exportation. 



The following estimate was given by MM. Dufr^noy and Elie do Beaumont of the 

 expense of manufacturing a ton of copper at the time of their visit to South Wales in 

 1822 : 



. s. d. 

 12 J tons of ore, yielding 8i per cent, of copper 55 



20 tons of coals 800 



Workmen's wages, rent, repairs, &c. . .1300 



76 



The exhalations from the copper smelting-works are exceedingly detrimental to both 

 vegetable and animal life. They consist of sulphurous acid, sulphuric acid, arsenical 



and arsenious acids, vari- 



508 ous acid and other va- 



pours, with solid particles 

 mechanically swept away 

 into the air. See p. 928. 

 The following figures 

 represent certain modi- 

 fications of the copper 

 calcining and smelting 

 copper furnaces of Swan- 

 sea. 



Fig. 608 is the section 

 of the roasting furnace 

 lengthwise ; fig. 509, the 

 ground plan; in which 

 a is the fire-door; b, 

 the grate ; c, the fire- 

 bridge ; d, the chimney ; e e, apertures on each side of the long sides of the furnace, 

 through which the ore is spread, and turned over ; //, iron hoppers ; g ff, openings in 

 the vaulted roof ; k the hearth-sole ; i i, holes in this ; k, a vaulted space under the 

 hearth. The hearth has a suitable oval shape, and is covered with a flat arch. Its 

 length is 16 feet, breadth 13 J feet, mean height 2 feet. 



