rate of increase was enormous. In 1845, 224,000
pounds were mined; in 1888, 226,000,000 pounds. Eight years later, in
1896, it had doubled; after another ten years, in 1906, it had doubled
that quantity, and reached 918,000,000 pounds. In 1890 we were using
three pounds of copper for every man, woman and child in the country.
And in 1907, six and one-half pounds.

Michigan, Montana, and Arizona produce the bulk of the copper. Utah,
California, Colorado, New Mexico, Wyoming, and Nevada each produce
copper in amounts ranging from the 66,000,000 pounds mined in Utah to
the 2,000,000 pounds mined in Nevada. It is probable that the use will
not increase so rapidly in the near future. Much old copper will be
remelted.

There are large areas of copper lands which are now classed as
"available" with copper at about its present price of thirteen cents a
pound. If the world production should grow so great as to cause a
decided drop in the price, much that is now considered available could
not be mined at a profit, and the copper supply from this country would
be greatly reduced. If, on the other hand, copper should rise to fifteen
or twenty cents or higher, the amount of available copper land would be
vastly increased. The report on the Conservation of Mineral Resources
says in effect: "The copper resources of the United States are believed
to be large enough to allow for a number of years for a demand
increasing at the rate of 30,000,000 pounds a year. Should this demand
continue for a long period the scarcity would be felt and result in a
rising price, which would open up a market for these low-grade ores and
also cause the use of other metals, like aluminum, to take the place of
copper whenever possible."

There is no great waste in the mining of copper, but in the extraction
of copper from the ore the waste is often as much as thirty per cent.,
and it is not easy to avoid this on account of the chemical changes that
take place.

LEAD

The United States produces about one-third of the lead in the world. The
remainder comes from Spain, where the production remains about the same
from year to year; from Germany, where in spite of higher prices
production is growing less; and from Australia and Mexico, in both of
which the supply is rapidly decreasing.

These facts show that the lead resources of the United States will be
drawn on heavily in the future. The production of the United States
increased from about 70,000 ton