TRON
939
IRON MOUNTAIN
I'ron, a metal in very common use, and in some of its combinations is found in large quantities, though native iron is very rare. The compounds of iron are found everywhere in the rocks and soil, and to these compounds the red color of rocks, soils, bricks etc. is due. ^Plants and_ animals cannot exist without iron, for it is a constituent of the green coloring matter of leaves and the red blood corpuscless. The iron used in trade is more or less impure, often containing carbon, silicon, sulphur and phosphorus. "Pig" iron or cast iron has the most impurities, while wrought iron has the least and is almost pure iron. Steel is intermediate between cast and wrought iron in the amount of foreign matter that it contains. Iron ore, the shape in which iron is found, is abundant and widely distributed. The magnetic ore is the richest, and is found in dark, heavy masses of black crystals. The red ore, brown ore and bog iron ore are other varieties. In the United States iron ore is found in large quantities and in nearly every state. The product of pig iron in the United States far exceeds that of Great Britain, being 27,303,567 long tons in 1910, against the yield in Great Britain of 10,012,098. Pennsylvania is the leading state in the manufacture of iron and steel; Ohio, Alabama and Illinois are also prominent. Tennessee, Virginia and Missouri are rich in iron ore. Iron Mountain in Missouri covers 500 acres, and has large veins of iron ore, though it is not a mountain of iron, as commonly supposed. The iron mines in the neighborhood of Lake Superior form some of the most wonderful deposits in the world. The first blast furnace was worked by William Penn in 1688, and the first rolling mill was started in 1817 at Plumstock, Pa. The best iron in Europe comes from the Dannemora mines in Sweden, which have been worked since the isth century. Russia, England, Germany, France, Sweden, Belgium, Austria-Hungary, Canada, Spain and Norway are iron-producing countries, The total product of the chief world countries in 1910 was: Pig iron 65,860,000 metric tons; steel 58,252,000 tons; Germany produced nearly a fifth of this total. The manufacture of steel in the United States in 1910 was 26,094,919 long tons.
The manufacture 01 iron dates back to early periods, and, though the methods have improved, all depend upon the use of furnaces. The Romans in Britain left great heaps of cinders so imperfectly worked that they have supplied much ore for use in modern furnaces. Charcoal was used in the furnaces until 1618, when coal was first tried, but did not come into general^ use until 1713. In 1750 coke was introduced. The process of puddling and rolling was invented by Cort in 1784, and the use of the hot blast by Neilson in 1830. The
greatest improvement of modern times is what is called the Bessemer process for making steel. (See BESSEMER.) The uses of iron are too numerous to mention, and are increasing rapidly. See Iron, History, Properties and Processes of Manufacture by Fairbairn; Manufacture of Iron by Overman; and Campbell's Manufactures and Properties of Iron and Steel. H. L. WELLS.
Iron Age, a term indicating a degree of culture in a people, as shown by their use of iron tools or weapons. It is the latest of the ages called the Stone, Bronze and Iron Ages. But this order is not followed strictly in all parts of the world; for, as in parts of America, the natives seem to have passed from the use of stone to that of iron. When America was discovered, the Indians did not use wrought iron. In Europe the iron age began earlier in the south than in the north. Greece was entering the iron age in the time of Homer; while Scandinavia reached it about the beginning of the Christian era. The tools and weapons of the iron age differ from those of the bronze age in being hammered instead of cast into shape, and in being ornamented with curving instead of with straight lines. But the important distinction is the use of alphabetic characters, which indicate a written language.
Ironclads. See NAVY.
Iron Mask, The Man with the. The story ^of the prisoner, so-called, has long held its place among the most romantic stories of history. He was supposed to be the duke of Vermandois, a son of Louis XIV and Mdlle de la Valliere. Becoming angry one day, he boxed the ear of his half-brother, the dauphin. For this offense he was imprisoned for life. Voltaire, in his history of Louis XIV, speaks of the young prince as a noble-looking figure, who, in being led from one prison to another, wore an iron mask concealing his face. He was at last transferred to the Bastille, where he was treated with great distinction. He died in 1703. Other theories make this French state prisoner the brother of Louis XIV. See Age of Louis XIV by Voltaire.
Iron Mountain. A famous deposit of iron ore gives the name of this mountain, which is situated in St. Francois County, Mo. The ore is rich and yields 68 per cent, of iron. It is magnetic, and in some places acts strongly on the needle. Its main body has a thickness of 50 feet. Since 1845 over 5,000,000 tons have been shipped.
Iron Mountain, Mich., a city and the county-seat of Dickinson County, is about 57 miles west of Escanaba. Its trade is principally in iron ore ^and farm products, for the city is in the vicinity of iron mines and Wisconsin farms. It is served by the Chicago, Milwaukee and St. Paul and Chicago and Northwestern railways. Population 9,216.
