At the present time there are several great centres of production which yield most of the metal used. These are the Rocky Mountain region, including Mexico; the Lake Superior region of the United States; the Andean region, including Chile, Peru, Argentina, and Bolivia; the Iberian region, consisting of Spain and Portugal; and the Hartz Mountain region of Germany. In 1900 they produced about four hundred and fifty thousand tons, of which two hundred and eighty thousand were mined in the United States.

Montana, the Lake Superior mines, and Arizona are the most productive regions of the United States, and the mines of these three localities yield more than half the world's product. Of these mines the Calumet and Hecla of the Lake Superior region is the most famous. It was discovered by Jesuit explorers about 1660, but was not worked until 1845. It is one of the most productive mines in the world, its yearly output averaging fifty million tons.

The export trade in copper is very important, amounting at the close of the past century to about one hundred and seventy thousand short tons.

Of this amount, half goes to Germany (most of it through ports of the Netherlands), and one-fifth each to France and Great Britain. The market price to the consumer during the ten years closing the century averaged about sixteen cents per pound. Most of the product is exported from New York and Baltimore. The head-quarters of the great copper-mining companies of America are at Boston. The imports of raw ores and partly reduced ores called "regulus," come mainly from Mexico to New York and Baltimore, and from Mexico and j.a.pan to Puget Sound ports. The most important American refineries are at New York and Baltimore.

A part of the copper is mixed with zinc to form bra.s.s, an alloy much used in light machinery. A considerable quant.i.ty is rolled into sheets to sheath building fronts and the iron hulls of vessels. By far the greater part, however, is drawn into wire for carrying electricity, and for this purpose it is surpa.s.sed by silver alone. The decrease in the price of copper in the past few years is due, not to a falling off in the demand, but to methods of reducing the ores and transporting the product more economically.

=Aluminium.=--Aluminium is the base of clay, this mineral being its oxide.

It occurs in the various feldspars and feldspathic rocks, and in mica.

The expense of extracting the metal from these minerals has been so great as to prohibit its commercial use. In 1870 there were probably less than twenty pounds of the metal in existence, and it was to be found only as a curiosity in the chemical laboratories. The discovery that the metal could be extracted cheaply from cryolite, a mineral with an aluminium base, obtained from Ivigtut, Greenland, led to a sparing use of the metal in the economic arts.

The chief step in the production of the metal dates from the time that the mineral _bauxite_, a hydroxide of aluminium and iron, was decomposed in the electric furnace. The process has been repeatedly improved, and under the patents covered by the Hall process the crude metal is now produced at a market price of about eighteen cents per pound. The entire production of the United States is controlled by the Pittsburg Reduction Company, which also manufactures much of the commercial product of England. The compet.i.tor of the Pittsburg Reduction Company is an establishment in Germany, near Bremen.

Aluminium does not corrode; it is easily rolled, drawn, or cast; and, bulk for bulk, it is less than one-third as heavy as copper. Because of these properties it has a great and constantly growing economic value.

Because of its greater size, a pound of aluminium wire will carry a greater electric current than a pound of copper wire of the same length.

It therefore has an increasing use as a conductor of electricity.

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 a.r.s.enic 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 quant.i.ties as compared with iron, copper, gold, and silver. Some of them, however, are highly important from the fact that in various industrial processes no subst.i.tutes 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.

_Tin_ is about the only metal of industrial value whose ores are not found in paying quant.i.ties in the United States. Small quant.i.ties occur in San Bernardino County, Cal., and in the vicinity of Bering Strait, Alaska, but it is doubtful if either will ever pay for development.

About three-fifths of the world's product comes from the Straits Settlements on the Malay Peninsula; the nearby islands of Banca and Billiton also yield a considerable quant.i.ty.

The mines of Cornwall, England, have been worked for two thousand years and were probably the source of the tin that made the "bronze age." The United States imports yearly about twenty million dollars worth of tin, about half of which comes from the Straits Settlements. This is used almost wholly for the manufacture of tin plate[48]--that is, sheet-iron coated with tin. Much of the block tin imported from Great Britain is returned there in the form of tin plate, being manufactured in the United States much more economically than in Europe.

_Nickel_ occurs in New Caledonia, in Canada, and in the State of Missouri. It is used in the manufacture of small coins and for plating iron and steel. It is an essential in the metal known as "nickel steel"

which is now generally used in armor-plate and propeller-shafts, about four per cent. of nickel being added to the steel. Most of the product used in the United States is imported from Canada.

_Manganese_, a metal resembling iron, occurs in Russia, Brazil, and Cuba, Russia producing about half the total output. It is used mainly to give hardness to steel. The propeller-blades of large steamships are usually made of manganese bronze. The building of war-ships in the United States during the past few years has led to the extensive use of manganese for armor-plate, and manganese ores to the amount of more than two hundred and fifty thousand tons were imported in 1900. More than one-half of this came from Russia; most of the remaining half from Brazil.

_Zinc_ is abundant in nearly every part of the world. In the United States the best known mines are in the Galena-Joplin District, in Missouri and Kansas, which produce about two-thirds of the home product--mainly from the ore _blende_, a sulphide. There are also extensive zinc-mining operations in Illinois, New Jersey, and Pennsylvania. The lower Rhine District, Great Britain, and Silesia are the chief European sources. Sheet-zinc is found in nearly every dwelling in the United States, and zinc-coated or "galvanized" iron has become a domestic necessity. Zinc-white is extensively used as a pigment. About two hundred and fifty million pounds of crude zinc, or "spelter," are produced in the United States; forty-five million pounds were exported in 1900, mainly to Great Britain.

QUESTIONS FOR DISCUSSION

What are the qualities that make iron the most valuable of metals?

In what ways does commerce depend on iron and steel?

What substances are used for food, clothing, or domestic purposes that are not manufactured by the aid of iron?

Ingot or billet steel is rated at about one cent per pound; the hair-springs of watches are worth several thousand dollars per pound; what makes the difference in their value?

What are the qualities that give to gold its value?

Would all the gold mined in the United States pay the national debt at the end of the Civil War?

What causes have led to the increasing price of copper during the past few years?

What is the market price each of copper, silver, steel rails, and aluminium to-day?

FOR STUDY AND REFERENCE

Obtain specimens of the following iron ores: Hemat.i.te, brown hemat.i.te, magnet.i.te, carbonate, and pyrites. Note the color and physical appearance of each; scratch the first four with a very hard steel point and note the color of the streak.

Obtain specimens of pig-iron, cast iron, wrought iron, and cast steel; note carefully the fracture or "break" of each; how does cast iron differ from wrought iron?

Obtain specimens of the following copper ores: Malachite, azurite, chalcopyrite, and red oxide; wet a very small fragment with an acid and note the color when it is held in the flame of an alcohol lamp or a Bunsen burner; dissolve a crystal of blue vitriol (copper sulphate) in water and note what occurs if the end of a bright iron wire be dipped in the solution.

Name the various uses to which nickel, tin, lead, and aluminium are put.

Consult the chapters on these subjects in any cyclopaedia.

[Ill.u.s.tration: TRANSPORTING SUGAR-CANE, CUBA]

[Ill.u.s.tration: SUGAR-CANE GROWING IN CUBA]

[Ill.u.s.tration: HAVEMEYER SUGAR-REFINERY, BROOKLYN, N.Y.]

CHAPTER XIV

SUGAR AND ITS COMMERCE

The term sugar is applied rather loosely to a large number of substances characterized by the quality of sweetness. In a few instances the name is given to certain mineral salts, such as sugar of lead, but in the main the sugars are plant products very similar in chemical structure to the starches. They are very closely connected with plant growth, and even in animal life, starchy substances are changed to sugar in the process of digestion. Although sugar does not sustain life, it is necessary as an adjunct to other food-stuffs, and it is probably consumed by a greater number of people than any other food-stuffs except starch and water.

Three kinds of sugar are found in commerce, namely--_cane_-sugar, _grape_-sugar, and _milk_-sugar. Cane-sugar occurs in the sap of the sugar-cane, sorghum-cane, certain of the palms, and the juice of the beet. Grape-sugar is the sweet principle of most fruits and of honey.

Sugar of milk occurs in milk, and in several kinds of nuts.

=Sugar-Cane Sugar.=--Cane-sugar is so called because until recently it was derived almost wholly from the sap of the sugar-cane (_Saccharum officinarum_). The plant belongs to the gra.s.s family and much resembles maize before the latter has matured. It is thought to be native to Asia, but it is now cultivated in nearly all tropical countries in the world.

Practically every moist tropical region in the world, the basins of the Kongo and Amazon Rivers excepted, is a cane-sugar-producing region. As a rule it is grown in the states under native rule for home consumption, and in European colonial possessions for commercial purposes. India and China are probably the foremost in the production of sugar-cane sugar, but the product is not exported. Cuba, Java, the Gulf coast of the United States, Mauritius, the Philippine and the Hawaiian Islands produce the most of the supply that enters into commerce.