Zinc
a bluish white metal with a brilliant lustre. It resembles tin, melts at 433 deg, and is easily vaporized. It is obtained from zinc ores by heating in a retort. The vapor is cooled into a liquid and is cast into plates called spelter. A second distillation gives zinc, free from iron, arsenic, and other foreign ingredients. In the United States zinc ores are found in association with lead throughout the Missouri lead district. Joplin, Missouri, is the American center of production. Next to the mines of the Mississippi region, the zinc ores of Sussex County, New Jersey, are the most important. Zinc is obtained in Colorado and in Wisconsin. A zinc mine located in blue magnesium limestone of the Saucon Valley, Pennsylvania, has fallen off in production. Foreign zinc mines are found near Cologne and Aix-la-Chapelle, also in Belgium, Great Britain, Italy, the Black Forest, Sardinia, Sweden, Siberia, Spain, Austria, and Poland.
Zinc is much used for coating iron as a preventive against rust--galvanized iron, the product is called. White metal buttons are made from an alloy of zinc and copper. Imitation gold used for gilding is made by an alloy of zinc with copper. Brass contains from sixty-six to seventy-three per cent of zinc, the rest being copper. Zinc roofing is not uncommon. Being a poor conductor of heat sheets of zinc are an excellent fire shield for woodwork. The round sheets used under a stove are not infrequently termed stove zincs. Zinc white is a substitute for white lead in the preparation of paints. Zinc sulphate or white vitriol is extensively used in the preparation of calicoes, and by the druggist in compounding medicine.