Ochers and metallic paints are iron oxides. Prussian blue and copperas are iron compounds.
The United States manufactures more iron and steel than any other country. Almost half of the production is in Pennsylvania. Cast iron appears in many articles but is weaker than other forms of iron. Wrought iron contains less impurity and is used for bars, plates, wire, structural material and parts of machinery. Steel (Bessemer, Siemens-Martin, open hearth, etc.) contains more carbon than wrought iron, possesses both strength and hardness, and is used for rails, structural material, machinery, tools, wire rope, sheet steel, etc. Its hardness may be increased by tempering. The United States imports iron ore from Cuba and Spain, pig iron from Great Britain and a little manufactured iron and steel from Europe. We export large quantities of manufactured iron and steel.
Lanthanum. See [rare metals].
Lead is the softest, heaviest, most malleable and most easily melted of the common metals. Its ores are found in many countries but the main supply is from the United States, Spain, Germany and Mexico. The chief lead mines of the United States are in Missouri, Idaho, Utah, Colorado and Kansas. Much lead bullion is from smelters where silver ores are reduced.
Galena (lead sulphide) is the only important ore; it often carries a considerable percentage of silver. Carbonates and sulphates of lead are less common. Solder and type metal are alloys of lead with tin and antimony. White lead is a carbonate, red lead and litharge are oxides. Chrome yellow and orange mineral are lead compounds used as pigments.
The chief use of metallic lead is in piping, sheet lead, shot and alloys. Large amounts of ore are transformed not into metallic lead but into white lead for use in paints. Lead ores and lead bullion are imported from Mexico. England is the greatest importer of lead and lead ores.
Lithium is the metallic base of the Alkali lithia. The metal is of a white, silvery appearance, and is much harder than sodium or potassium, but softer than lead. It is the lightest of all known solids, its specific gravity being little more than half that of water. It comes principally from South Dakota, California and Sweden.
In chemical laboratories it is converted into lithium carbonate for medicinal tablets and mineral waters.
Magnesium is a metal widely distributed over the globe, and chiefly mined in Austria, Germany and Greece. The metal is used in flash powders for photographic use, and in chemical manufacture, in fireproofing and lining furnaces.
Magnesite (magnesium carbonate) is used in making carbon dioxide gas and epsom salts and for preparing magnesia (calcined magnesia).