ealth that he brings into existence.
Interest on capital needs, in like manner, to be productivity
interest, and each unit of capital must get the amount it creates.
Moreover, the prices of goods, as expressed in money, must be accurate
representations of the comparative values of goods. All these features
mark the static state; but the most obvious mark of distinction is the
absence of movement from group to group. We shall see that values are
ultimately measured in marginal labor, and as the value of money is
measured in the same way, it follows that the price of each article,
as expressed in money, is in a static state a correct expression of
the comparative amount of labor that will make it. And the entire
relation of commodities to each other and to labor can be expressed by
the medium of currency. If a unit of labor produces gold enough to
make an eagle, and if any commodity sells for ten dollars, it will be
safe to infer that it is also produced by one unit of labor. If one
commodity sells for ten dollars and another for five dollars, the
former is the product of twice as many units of marginal labor as is
the latter. This remains true only while currency continues to be in
its normal state and all other static adjustments continue complete.

_Influences that disturb the Static Equilibrium._--It might seem that
the influences that disturb such a static equilibrium are too numerous
to be described; and yet these changes may be classed under five
general types:--

1. _Growth of Population._--The supply of labor is increasing, and
this fact of itself calls for continual readjustment of the group
system.

2. _Increase of Capital._--The amount of capital is increasing, and
this change also disturbs the static equilibrium and calls for a
rearrangement. As far as wages and interest are concerned, the effect
of this latter change is the opposite of that which follows an
increase in the amount of labor. When people become more numerous,
other things remaining equal, their individual earning capacity
becomes smaller. The increase of capital reduces the earning power of
each unit of the supply of it and depresses the rate of interest; but
it raises the rate of wages, for it causes labor itself to act more
efficiently.

It is to be noted, indeed, that when new laborers enter society they
become consumers as well as producers, and this affects the utility
and the value of goods. When more people use a given amount of
co