constantly increasing--losses due to rusting,
ship-wrecks, etc., being only a small fraction of the annual
output--suggests that a point will be reached where new production will
cease to accelerate at the present rate and may even decline. But again,
the factors are so complex and many of them so little known, that no one
can say how soon this point will be reached.

For the immediate future, there is little to be feared from shortage of
mineral supplies in the ground. The difficulties are more likely to
arise from the failure of means to extract and distribute these supplies
fast enough to keep up with the startling acceleration in future demand
indicated by the figures of recent years. The speed and magnitude of
recent material developments in many lines cannot but raise question as
to whether we have the ability to understand and coodinate the many
huge, variable, and accelerating factors we have to deal with, or
whether some of the lines of development may not get so far ahead of
others as to cause serious disturbance of the whole material structure
of civilization. Coal alone, which now constitutes a third of our
railway tonnage, may with increased rate of production require
two-thirds of present railway capacity. Will railway development keep
up? It may be noted that national crises and failures in the past
history of the world have seldom, if ever, been due to shortage of raw
materials, or in fact to any failure of the material environment.

In its early stages the conservation movement in this country concerned
itself principally with the raw material. Later there came the
recognition of the fact that conservation of raw materials is closely
bound up with the question of conservation of human energy. The two
elements in the problem are much like the two major elements in mineral
resource valuation (see pages 329-330). If in saving a dollar's worth of
raw material, we spend two dollars worth of energy, it naturally raises
question as to the wisdom of our procedure. It might be wiser in some
cases to waste a certain amount of raw material because of the saving of
time and effort. It might be better for posterity to have the product of
our energy multiplied into raw material than to have the raw material
itself. The valuation of these two major elements of conservation is
again almost impossible of quantitative solution. We do not know what is
the best result to be aimed for. We cannot foresee the requirements of