ky 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 Japan 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 brass, an alloy much
used in light machinery. A considerable quantity 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 surpassed 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