The extraction of mineral resources on the huge scale above indicated is
of comparatively recent date.

From 1880 to the end of 1918 the value of the annual mineral production
of the United States has increased from $367,000,000 to more than
$5,500,000,000, or nearly fifteen times; measured in another way, it has
increased from a little over $7 per capita to more than $52.[10]

More coal has been mined in the United States since 1905 than in all the
preceding history of the country. More iron ore has been mined since
1906 than in all the preceding history. The gold production of the
United States practically started with the California gold rush in
1849. The great South African gold production began in 1888. Production
of diamonds in South Africa began about 1869. The large use of all
fertilizer minerals is of comparatively recent date. The world's oil
production is greater now each year than it was for any ten years
preceding 1891, and more oil has come out of the ground since 1908 than
in all the preceding history of the world. The use of bauxite on a large
scale as aluminum ore dated practically from the introduction of
patented electrolytic methods of reduction in 1889.

In one sense the world has just entered on a gigantic experiment in the
use of earth materials.

The most striking feature of this experiment relates to the vast
acquisition of power indicated by the accelerating rate of production
and consumption of the energy resources--coal, oil, and gas (and water
power). Since 1890 the per capita consumption of coal in the United
States has trebled and the per capita consumption of oil has become five
times as great as it was. If the power from these sources used annually
in recent years be translated roughly into man power, it appears that
every man, woman, and child in the United States has potential control
of the equivalent of thirty laborers,--as against seven in 1890. Energy
is being released on a scale never before approximated, with
consequences which we can yet hardly ascertain and appraise. This
consideration cannot but raise the question as to the ability of modern
civilization to control and coodinate the dynamic factors in the
situation.

CAPITAL VALUE OF WORLD MINERAL RESERVES

It is impossible to deduce accurately the capital value of mineral
resources from values of annual output, but again some approximation may
be made. The profit on the extraction of mineral resources on the whole,
c