diminishing returns applies to mining as well as to
agriculture. The more silver you want, the deeper you must dig for it,
and the more refractory ores you must smelt. The transmuting of a raw
metal into finished articles becomes a cheaper and cheaper process;
but the extracting of the metal itself becomes dearer. A larger and
larger fraction of the labor that is spent in making wares of silver,
of gold, of copper, or of tin must be spent in getting the crude
material out of the earth. There are improvements in mining, as there
are in other industries, and there are large improvements in smelting;
but in spite of this the continual working of more difficult mines and
of more difficult ores makes the getting of the crude material, in
the long run, relatively costly. Since a coin consists chiefly of raw
metal, we may therefore count on having before us a regime of falling
prices, whatever metallic currency we adopt. The rate of the fall and
the degree of steadiness in it will be greater with some metals than
with others. The variations in the value of gold are, on the whole,
comparatively steady. This metal fluctuates in amount and in cost, but
the changes are less sudden than in the case of most others.

_The Steadiness of the Change in the Purchasing Power of Money the
Important Fact._--A second fact to be noted is that the best currency
is one the purchasing power of which shall change, if at all, at a
comparatively uniform rate. This fact is of paramount consequence, and
the verification of it will repay any amount of study. It is not the
rapidity with which gold gains in purchasing power, but the steadiness
of the gain from year to year that determines whether it is the best
money that can be had by the business world. A _change in the rate_ of
increase in the purchasing power of the coinage metal has a really
disturbing effect; a steady and calculable appreciation does not.
There exists in some acute minds what I venture to call a delusion
about the effect on business classes of an advance in the purchasing
power of gold that proceeds for a long time at a uniform rate.
Conceding the prospect of a decided gain in the value of this metal,
we may deny absolutely that, if _it is steady_, it plays into the
hands of creditors, burdens the _entrepreneur_, blights enterprise, or
has any of the effects that certain men whom we are bound to respect
have claimed for it. Irregular changes of value would, indeed, produce
these