Prince Rupert's metal, 2 parts of copper; 1 part of zinc.
Red brass, 16 copper ; 2 zinc.
Yellow brass, 60 copper; 40 zinc.
Sheet brass, 16 copper; 3i zinc.
Soft brass, 4 copper; 1 zinc. This is an easy working metal, can be read ily sawed, and is a very useful brass.
Dipping metal, 16 copper; 7 zinc.
Brazing solder, 16 copper; 14 zinc.
Mosaic gold, I copper; 1 zinc. Or equal parts by weight. Melt the cop per and keep it at the lowest temper ature at which it will stay melted. Add the zinc in small pieces, stirring constantly until the alloy turns white. Then cover with air-slaked lime, heat it to the desired temperature, and pour. More zinc than copper may be required, because some of the zinc may pass off as gas.
Tombac, pinchbeck, Mannheim gold, similore, and the like contain SO parts or more of copper and 20 parts or less of zinc.
Bronze.—Bronze is an alloy of cop per with tin, or tin and lead, or tin and zinc, or with all three. Sometimes other metals are also added in small proportions. The hardest and finest bronze consists of tin alone with cop per in the proportion of about 9 parts of copper to 1 part of tin. Bronze is extensively used in the arts for cast ing metals and statues; also in casting bells, cannon, and machinery. Bronze was used in the earliest times for weapons and utensils before iron was discovered. Hence scholars tell of an " age of bronze " which came after the " age of stone" and before the " age of iron." Tempering has exactly the opposite effect on bronze to what it has on steel. Hence, to draw the temper of bronze and make it soft and malle able, it must be heated to a cherry red and quenched in water.
The following are various kinds of bronze, adapted to different purposes: Bronze cannon, 9 copper, 1 tin; Chinese gongs, 5 copper, 1 tin; musi cal bells, 6 copper, 1 tin; house bells, 4 copper, 1 tin; large bells, 3 copper, 1 tin; bronze for wheels, 10 copper, 1 tin; speculum or telescope metal, 2 copper, 1 tin; mechanical instru ments, 12 copper, 1 tin; soft bronze, 16 copper, 1 tin; bronze for gears, 16 copper, 1 tin; gun metal, 16 copper, 2 tin; bronze bearings, 16 copper, 2i tin; cutting tools, 100 copper, 14 tin.
The ancient cutting instruments of bronze are superior to any of modern make, but this is supposed to be due to an art of tempering, which has been lost, as their composition varies from 4 to 14 per cent of tin. The
addition of zinc, lead, and other ma terials produces another class of al loys, including the following: Standard bronze, 12 copper; 1 tin; I lead.
Bronze for journal boxes, 24 cop per; 94 tin; 8 antimony. First melt the copper, then add the tin, and final ly the antimony. Run into ingots and melt down before casting.
Bronze for ornaments, 82 copper; 18 zinc; 3 tin; 3 lead.
Bronze for general work, 16 cop per; 1 tin; 1 zinc; lead.
Strong bronze, 10 copper; 1 tin; brass; lead.
Bronze for gun metal, S copper; 1 tin; zinc; lead.
Cheap bronze, 30 copper; 15 old brass; 1 tin; 2 lead.
Bronze solder, 39i copper; 7i zinc; 3 tin. Use to unite iron to brass.
Artificial gold, 100 copper; 17 tin; 6 magnesia; 9 commercial tartar; sal ammoniac, 1; quicklime. First melt the copper, to which add the mag nesia, sal ammoniac, lime, and tartar in the order named. Stir these in slowly in powdered form; then stir vigorously for 20 to 30 minutes un til all are incorporated. Throw the tin on the surface in small grains, and stir until entirely melted. Cover the crucible and let stand for half an hour. Skim off the dross and pour. This is a beautiful alloy, of a color similar to gold, is malleable and duc tile, and may be worked like gold. It requires a good judge to tell the dif ference. Or 94 copper and 6 anti mony, said by French experts to be a wonderful substitute for gold. It can be polished to almost exactly the same color as gold, and can be worked in the same manner.
Bronze jewelry, 3 copper; 1 brass; tin.
White metal, 8 brass; 10 tin; 10 lead; 6 bismuth; antimony. Melt together and run into molds. This alloy is malleable, closely resembles silver, and is used for the manufac ture of cheap tableware and various ornaments. Or, for hard white metal, 20 brass; 3 zinc; 1 tin.
Aluminum bronze, 90 copper; 10 aluminum.
Manganese bronze, 80 to 90 copper; 20 to 10 manganese.
Phosphor bronze, any standard bronze melted in the presence of phos phorus, and usually retaining a small amount of that substance.
The last three are all valuable al loys, stronger and better than pure bronze.