to twenty
years. Of course production could not continue to the end at this rate,
and the actual life will necessarily be longer. Again the doubtful
factor is the possibility for further discoveries. Many favorable
structures have been mapped which have not yet been drilled, and there
are considerable unexplored areas where the outcrops are so few that
there is no clue at the surface to the location of favorable structures.
The future is likely to see a considerable amount of shallow drilling
for the sole purpose of geological reconnaissance. For upwards of ten
years important parts of the public domain have not been available for
exploration, but Congress has now enacted legislation which opens up
vast territories for this purpose.

Even with large allowance for these possibilities, it seems unlikely
that production in the United States can increase very long at the
accelerating rate of the domestic demand, which is already in excess of
domestic production. The supplies of Mexico are in a large part
controlled by American capital and are thus made available to the
United States (subject, of course, to political conditions); but even
with these added, the United States is in a somewhat unfavorable
situation as compared with certain other countries. This situation is
directing attention to the possibility of curtailment of oil exports,
and to the possibility of acquiring additional oil supplies in foreign
countries. In this quest the United States is peculiarly handicapped in
that most foreign countries, in recognition of the vital national
importance of the oil resource, have imposed severe restrictions on
exploration by outsiders. Nationals of the United States are excluded
from acquiring oil concessions, or permitted to do so only under
conditions which invalidate control, in the British Empire, France,
Japan, Netherlands, and elsewhere, and the current is still moving
strong in the direction of further exclusion. As the United States
fields are yet open to all comers, it has been suggested that some
restriction by the United States might be necessary for purposes of
self-protection, or as an aid in securing access to foreign fields. The
activity of England during and since the war has increased the amount of
oil controlled by that country from an insignificant quantity to
potentially over half of the world's oil reserves. The problem of future
oil supplies for the United States presents an acute phase of the
genera