Bauxite, the mineral from which the metal is now chiefly extracted, is obtained in two localities. One extends through Georgia and Alabama; the other is in Arkansas. =Lead.=--Lead is neither so abundant nor so widely diffused as iron, copper, and the precious metals, but the supply is fully equal to the demand. Lead ores, mainly galena or lead sulphide, occur abundantly in the Rocky Mountains, Colorado, Idaho, and Utah, producing more than half the total output of the United States. In these localities, in Mexico, and in the Andean states of South America it is used mainly in the smelting of silver ores. Metallic lead is used largely in the manufacture of water-pipes, and for this purpose it must be very nearly pure. It is also rolled into sheets to be used as lining for water-tanks. The fact that the edges of sheet-lead and the ends of pipes may be readily joined with solder gives to lead a great part of its economic value. Alloyed with arsenic it is used in making shot; alloyed with antimony it forms type metal; alloyed with tin it forms pewter and solder. The greater part, however, is manufactured into the carbonate or "white" lead that is used as a pigment, or paint. Red lead, an oxide, is a pigment; litharge, also an oxide, is used for glazing the cheaper kinds of pottery. About two hundred and thirty thousand tons of lead are produced in the United States and one-half as much is imported--mainly from Mexico and Canada. The linotype machines, now used in all large printing establishments, have increased the demand for lead. =Other Metals.=--Most of the remaining economic metals occur in small quantities as compared with iron, copper, gold, and silver. Some of them, however, are highly important from the fact that in various industrial processes no substitutes for them are known. _Quicksilver_, or _mercury_, is the only industrial metal that at ordinary temperatures is a liquid. It is the base of the substance calomel, a chloride, and corrosive sublimate, a dichloride, both of which are employed as medicines. It is essential in the manufacture of thermometers and barometers, but is used chiefly, however, as a solvent of gold, which it separates from the finely powdered ore by solution or amalgamation. Quicksilver occurs in the mineral cinnabar, a sulphide. Nearly one-half the world's product comes from California. The New Almaden mines of Santa Clara County produce over five thousand flasks (each seventy-six and one-half pounds net); those of Napa County nearly nine thousand flasks; the mines of the whole State yield about twenty-six thousand flasks, valued at $1,200,000. Almaden, Spain, and Idria, Austria, produce nearly all the rest of the output. An average of about fifteen thousand flasks are exported from San Francisco, mainly to the mines of Mexico, and Central and South America.