Tin
a well known silvery white metal. It is softer than lead and may be hammered or rolled into exceedingly thin sheets known as tin foil, but grows brittle at a temperature of 200 deg. C. and melts at 228 deg. Tin ore or tin stone is a compound of tin and oxygen. It occurs chiefly in granite rocks where it is mined like gold ore, but, like gold dust, it is also to be sought in the gravel of valleys where it has been carried by torrents as the granite ledges have crumbled away. Tin occurs in nearly all the granite states of the Union. The mountains of New England, the Shenandoah Valley, Virginia, North Carolina, and California have yielded tin ore in small quantities, but the only American mines of consequence are found in the Black Hills of South Dakota. The entire American production is about 30,000 long tons yearly.
The tin mines of Cornwall in England are celebrated and have supplied a large part of the world with tin since the day of Julius Caesar. The Phoenicians employed slaves to work the tin mines of Spain. Agricola, an early Roman historian, mentions the tin mines of Portugal. The granite ledges and gravels of Devonshire, Brittany, Bohemia, Finland, and Mexico, produce tin. The enormous modern demand for tin has been met in part by the Straits Settlements of Asiatic waters, at present the most important tin-producing district in the world. The mines of southeastern Asia have been worked for 400 years. It is thought that long ago they must have furnished the tin employed in the manufacture of the implements used in the prehistoric bronze age. In the southern hemisphere, tin is found in Australia, Tasmania, and Bolivia.
A considerable portion of the tin supply goes into the manufacture of bronze, for an account of which the reader is referred to the article under that title. Britannia metal, used in the manufacture of toys and of tableware designed to imitate silverware, is composed of from eighty-two to ninety parts of tin alloyed with antimony and a small admixture of copper and sometimes zinc. Pure tin, like silver, resists rust. Tinware is made of sheet iron coated with tin, which, especially in the case of tin cans for preserving vegetables and fruits, excludes the air and prevents decay. America is obliged to send more money abroad for tin than for any other metal. We import 95,000,000 pounds a year from England and the East Indies.
To make commercial tin out of this imported ingot tin, steel or iron plates are dipped in a tank of molten tin and are then annealed by a proper degree of heat in ovens. The American manufacture of so-called tin employs 25,000 people and reaches the enormous volume of 1,000,000,000 pounds a year, unprecedented in the world's history. Formerly tinware was made by cutting the material into suitable sheets and soldering them together, but now almost all "tin" goods are made by stamping the article out of a single sheet. Several thousand people are engaged in this work, to say nothing of japanned and enameled tinware. Half of the world's supply of tin is consumed in the United States. The price in New York has ranged in recent years from twenty-nine cents to thirty-eight cents per pound. American manufacturers of tin plate are protected by a duty of one and one-half cents per pound.