lead to
German developments in eastern Europe and western Asia, particularly in
the large and favorably located reserves of southern Russia. It seems
likely, however, that arrangements will also be made to continue the
export of ore from the Lorraine field down the Rhine to the principal
German smelting centers. France needs the German coal for coking as
badly as Germany needs the French iron ore. The Rhine valley is the
connecting channel for a balanced movement of commodities determined by
the natural conditions. These basic conditions are likely in the long
run to override political considerations.

The Lake Superior deposits, the Swedish magnetites, the Spanish
hematites, and the Russian ores carry 50 to 65 per cent of metallic
iron. The Birmingham deposits of southeastern United States, the main
British supplies, and the main French and German supplies contain about
35 per cent or less. It is only where ores are fortunately located with
reference to consuming centers that the low-grade deposits can be used.
For outlying territories only the higher-grade deposits are likely to be
developed, and even there many high-grade deposits are known which are
not mined. The largest single group not yet drawn on is in Brazil.
Others in a very early stage of development are in North Africa and
Chile.

=World reserves and future production of iron ore.= The average rate of
consumption of iron ore for the world in recent years has been about 170
million tons per year. At this rate the proved ore reserves would last
about 180 years. If it be assumed that consumption in the future will
increase at about the same rate as it has in the past, the total
measured reserve would still last about a century. These calculations of
life, however, are based only on the known reserves; and when potential
reserves are included the life is greatly increased. And this is not
all; for beyond the total reported reserves (both actual and potential),
there are known additional large quantities of lower-grade ores, at
present not commercially available, but which will be available in the
future,--to say nothing of expected future discoveries of ores of all
grades in unexplored territories. Both geological inference and the
history of iron ore exploration seem to make such future discoveries
practically certain. Iron ore constitutes about 4 per cent of the
earth's shell and it shows all stages of concentration up to 70 per
cent. Only those rocks are