producing 45 per cent of the pig iron turned out in these four
countries. For 1918 the pig iron production of the United States was
39.1 million tons. That of the other three countries was 22.0 million
tons. In that year the United States produced 64 per cent of the pig
iron product of these four countries. An equally great lead is shown in
the case of steel production. In 1914 the United States produced 23.5
million tons of steel. Germany, the United Kingdom and France produced
27.6 million tons. By 1918 the production of the United States had
nearly doubled (45.1 million tons).

The total pig iron output of the world for 1917 was placed at 66.9
millions of tons. The world's production of steel in 1916 was placed at
83 million tons. The United States produced considerably more than half
of both commodities. ("The Mineral Industry During 1918." New York,
McGraw Hill Book Co., 1919, pp. 379-80).

The two chief forms of power upon which modern industry depends are
petroleum and coal. The United States is the largest producer of both of
these commodities. The world's production of petroleum in 1917 was 506.7
million barrels (_Mineral Resources_, 1917, Part II, p. 867). Of this
amount the United States produced 335.3 million barrels or 66 per cent
of the total. The second largest producer, Russia, and the third,
Mexico, are credited with 69 million barrels and 55.3 million barrels
respectively.

As a coal producer the United States stands far ahead of all other
nations. The United States Geological Survey (_Special Report_, No. 118)
placed the total coal production of the world in 1913 at 1,478 million
tons. Of this amount 569.9 million tons (38.5 per cent) were produced in
the United States. The production for Great Britain was 321.7 million
tons; for Germany 305.7 million tons; for Austria-Hungary 60.6 million
tons. No other country reported a production of as much as fifty million
tons. In 1915 the United States produced 40.5 per cent of the world's
coal; in 1917 44.2 per cent; in 1918 46.2 per cent.

Copper has become one of the world's chief metals. Two-thirds of all the
copper is produced in the United States. Copper production in 1916
totaled 3,107 million pounds (_Mineral Resources in the United States_,
1916, part I, p. 625). The production for the United States was 1,927.9
million pounds (62 per cent of the whole). The second largest producer,
Japan, turned out 179.2 million pounds.

The precious metals, gold