overcrowding does greater and greater harm the further it
is carried, and therefore taking away a surplus of people from a
region which has suffered greatly from overcrowding affords a relief
which more than offsets what is lost in other places by a moderate
increase of population. Moreover, the fact has to be recognized that
at present there are ten square miles of sparse population for one
that is very densely peopled, and reducing all to an equality would
add only slightly to the number of inhabitants of the regions that now
contain few of them.[1]

[1] Exceptional local conditions may make an influx of
population for a time a cause of greater productivity rather
than of less. The general and permanent effects are
otherwise, and it is on these that the present argument
rests.

[Illustration]

If the line _BB'_ represents the unequal level of _natural_ wages in
different localities, on the assumption that populations remain
unequal, the undulating curve _DD'_ which crosses and recrosses the
line _BB'_ represents actual local rates fluctuating about the
standard ones.

_How a Static Adjustment for the World is a Dynamic Influence within
a Limited Part of It._--Commodities are, by traffic, crossing the
social boundary in both directions, and with the goods there go and
come influences that affect the economic life of the central society.
Methods and modes of organizing business are taught by each region to
the other, though most of the teaching is done by the people of the
center and most of the learning by those of the environment. All this
affects the center and falls within our study. It has dynamic effects
within the center, though it is only a part of a static adjustment for
the world as a whole. If the grand bank of Newfoundland were to
subside to the level of the middle of the Atlantic, there would be a
great rush of water toward the place that the banks now occupy, but
this would be only what is required in bringing the general level of
the sea to an equilibrium. It would be essentially a static
phenomenon, but for the region of the banks it would be dynamic in the
highest degree. A rush of population from China to America would be a
change tending to establish an equilibrium of population in the world,
but it would be a startling bit of dynamics for America. Teaching the
Chinese all the mechanical arts that we know would be creating an
equilibrium of another sort, in which methods woul