Graphite is almost pure carbon. It is produced in Bohemia, Ceylon, Italy, Germany, Mexico and the United States. The deposits in Ceylon are the largest in the world. Much of that mined in New York and Alabama is of very high grade.
Plumbago or black lead is used in making crucibles, lead pencils, lubricants for heavy machinery, stove polish, foundry facings, paint, etc.
Artificial graphite is made from coal or coke by an electric process.
Powdered graphite is mixed with fine clay in greater or less proportion and then molded and baked to form such articles as crucibles and lead for pencils. Graphite is imported from Ceylon to the United States, and lead pencils from Europe.
Iron is the most useful of all metals. The United States, Germany, Great Britain, Spain and France are the greatest producers of iron. Its ores occur in almost all parts of the world. Hematite is mined in Minnesota, Michigan, Alabama and other parts of the United States and in Germany, England, France, Spain, Russia, etc. Limonite is also widely distributed. Pig iron is made by smelting iron ore in a blast furnace. The ore, mixed with limestone, is melted by burning coke, coal or charcoal.
Pyrite (iron pyrites, or fool’s gold) is found in Spain and many other parts of the world and is valuable in the preparation of sulphuric acid (oil of vitriol), but useless as an iron ore.
Hematite (sesquioxide of iron) is the ore which supplies three-fourths of the iron of commerce.
Limonite brown (hematite) is a hydrous oxide and furnishes nearly one-fourth of the world’s supply of the metal. Magnetite and siderite are less common ores.
Pig iron is the crude form of the refined metal and is transformed into cast iron, wrought iron and steel in their multitudinous forms.
These three forms of iron differ in hardness, strength, elasticity, malleability, etc., according to the amounts of carbon, sulphur, phosphorus, manganese and other elements.