ALLOYS, GOLD, SILVER, ETC.
Gold alloys. Standard gold for coin in Great Britain is: Pure gold, 22; pure copper, 2. This alloy is harder and more fusible but less ductile than pure gold. It is -said to be 22 carats fine. Standard gold for coin in United States and France: Gold, 9; copper, 1. Jeweler's gold varies from 22 down to 9 parts gold. with sufficient silver, or copper and silver, to make up 24 parts. The number of parts of pure gold in 24 parts of an alloy denotes its fineness; thus gold 18 carats fine is an alloy containing 18 parts of pure gold and 6 parts silver or copper.
Silver alloys are as follows: Standard silver for coin and plate in Great Britain: Pure silver, 222; pure copper,18. (Specific gravity, 10.2.) French standard silver for medals and plates: Silver, 95; copper, 5. American and French standard sil ver for coin : Silver, 90; copper, 10. French standard silver for jewelry work : Silver, 80; copper, 20. Silver solder: Silver,' about 66 per
cent. with zinc and copper.
Queen's Metal. Tin, 9; antimony, 1; lead, 1; bismuth, 1. Used.for teapots, spoons, etc.
Brass is made of copper, 64 parts; zinc, 36 parts; proportions slightly varied to make the metal darker by increasing the copper even to 74 per cent.
Bronze is made of copper, 85 to 90 parts; tin, 10 to 15 parts; sometimes a little lead and zinc is added.
Bell metal is made of copper, 75 parts, and tin, 25 parts.
German silver is made of copper, 16 parts; zinc, 7 parts, and nickel; 8 parts.
Type metal is made of lead, 83 parts; metallic antimony, 7 parts.
Stereotyping metal is made of lead, 9 parts; metallic antimony and bismuth, each 2 parts.
Common solder is made of lead and tin equal parts.
Fine solder is made of lead, 1 part; tin, 2 parts. Pewter is made of lead, 4 parts; tin, 1 part.