IT USED to be that wars were fought for gold, but nowadays the possession of rich iron mines is enough to arouse the cupidity of neighboring nations less favored by nature. In fact, even though an ounce of gold is worth twice as much as a ton of iron, the value of the iron we dig out of the earth each year is far greater than that of gold. When that rough ore is converted into iron and steel and then into thousands of useful articles, its value mounts so high that it cannot be estimated. The qualities of iron and its alloys are so excellent and so varied under different treatment that this metal may truly be said to form the foundation of all our mechanical progress. On the one hand it spans our wide rivers, carries the burden of heavy freight trains, or, in the form of armor plate, resists the terrific impact of high-powered shells; on the other hand the same metal, spun into a hair spring, governs the ship’s chronometer, or, in the compass, points a trembling finger to guide the navigator on his course. IRON IN ANCIENT DAYS The first use of iron in the service of man dates far back into the ages. An iron tool was found in the pyramid of Kephron which must have been used 3,500 years before Christ. However, because of the difficulty of working it, iron was not extensively employed except for swords and cutlery. The conversion of iron into steel and the tempering of steel blades grew to be an art which gave Damascus and Toledo a world-wide reputation that dates back over a thousand years. The ancients used to smelt their iron ore in what was known as a Catalan forge because of its extensive use in Catalonia, Spain. Whether the forge was invented there or not we cannot say. Similar forges have been found in India and other widely remote places. They comprised an inclined tray leading to a pot which formed the furnace and in which a charcoal fire was kindled. The ore and charcoal were placed on the tray and from time to time were raked down into the furnace and air was forced into the bottom of the furnace by means of bellows. In an improved form of the Catalan forge air was furnished by means of an air compressor operated by a stream of water. This has already been referred to and illustrated on page 90. Limestone served as a flux to melt the earthy matter. The iron obtained from these primitive furnaces was not heated sufficiently to flow as a stream, but was merely reduced to a pasty mass which was then hammered into shape by the blacksmith. Ten or twelve pounds of metal per day was considered a fair output for one of these forges. DISCOVERY OF COKE