the total
life of the coal reserves (to a depth of 3,000 feet) would be between
4,000 and 6,000 years; but if the acceleration of production of recent
years were to be maintained in the future, the life would be but little
over 100 years, and the life of the highest-grade coal now being mined
might not be over 50 years. All agree that the acceleration of
production is not likely to continue indefinitely, which will mean that
the life of coal reserves to 3,000 feet will be somewhere between the
two extremes named. It seems clear that actual shortage of coal will not
be felt for some hundreds of years; but this period of years is short as
compared with the probable life of the race.

MEASURES INTRODUCED OR PROPOSED TO CONSERVE COAL

The following list of measures for conservation of coal is taken from
several sources. The exhaustive report of the British Coal
Commission,[43] published in 1905, contains a considerable number of
specific recommendations for conservation of the coal of Great Britain.
The reports of the National Conservation Commission[44] of the United
States, published in 1909, treat of the conservation of the coal of the
United States and naturally follow some of the recommendations of the
British report. The coal section of the National Conservation report was
prepared by M. R. Campbell and E. W. Parker of the U. S. Geological
Survey, and is contained in U. S. Geological Survey Bulletin 394. The
recommendations there given are amplified and developed by Van Hise[45]
in his book on Conservation, published in 1910. Since that time the
subject has been discussed by Smith, Chance, Burrows, Haas,[46] and
others, and certain additional conservational methods have been
proposed. A considerable number of men have also discussed the
sociologic and economic aspects of the question. The report of the
Conservation Commission of Canada,[47] published in 1915, treats rather
fully of the conservation of mineral resources.

It will suit our purpose, and avoid some repetition, if we group most
of these recommendations without regard to authorship. In general, these
recommendations can be grouped under the heads: (A) Methods of mining
and preparation of coal; (B) Improvement of labor and living conditions
at the mines; (C) Introduction or modification of laws to regulate or to
remove certain restrictions on the coal industry; (D) Distribution and
transportation of coal; (E) Utilization of coal; (F) Substitutes for
coa