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of metal required to produce each dollars worth of product.
Nonetheless, demands for new metals have continued to
increase at a very rapid rate, and the amount of metals
in use relative to GNP has not changed markedly. Although
more is being made from each ton of metal, a greatly
increased volume of total production has swamped increases
in efficiency of metals use; the net effect has been a
continually increasing demand for new metals inputs.
These increases in the physical volume of
production often tend to be overlooked since changes in
production in the past century have improved product
quality so greatly. It is quite true that better
implements are being made of metal now than before; iron
used to produce a carriage wheel in i860 might today be
converted into stainless steel used in a supersonic
aircraft. But that fact should not distort the picture
relative to increases in volume. Very few supersonic
aircraft, or anything else for that matter, could be
produced if the amount of metal available for their
construction now were the same as it was in i860.
Improvements in quality have been the product of thought
and planning; increases in quantity have occurred
primarily as a result of increased extraction.
In the past, as projects for which metal was
destined were completed, the need for additional amounts
of the metal to satisfy those ends diminished, a
phenomenon best illustrated by the virtual