ovements go on within
the center. The grand resultant is more rapid progress within the
center.

_What is involved in a Full Study of the Relative Density of
Populations._--A full treatment of the subject of the comparative
density of population in different places would include an extended
study of the kinds of industry which find their natural homes in
densely peopled countries and of those which flourish in sparsely
peopled ones, and a much more detailed tracing than it is possible
here to undertake of those changes in the character of industries
everywhere which result from a leveling out of differences in
population. Clearly, if all America were to become as crowded with
inhabitants as are Holland and Belgium we should develop industries of
a different type from those that we now have, and the change would be
in the direction of producing relatively more form utilities and
relatively less of the elementary utilities. Labor and capital would
move from the subgroups which in our table we have called _A_, _B_,
and _C_ toward _A'''_, _B'''_, and _C'''_. We should spend more of our
energy in making finished goods and less in getting raw materials. I
shall note in a very general way the changes in social industry caused
by increase of population without looking forward to that remote time
when the density of population shall be equalized.

_Why an Approximately Static Adjustment of Industries within the
Central Area permits Unequal Density of Population in Different Parts
of It._--We exclude from view the ultimate static adjustment of the
whole world, and content ourselves with an approximate adjustment
within society as we have defined it. Even within this limit there are
inequalities in the density of population which it would require a
very long time to remove, and a perfectly static state cannot be
reached till they are leveled out. The selection of industries in
Texas and in Belgium cannot be, in the ultimate sense, natural till
population in these two regions is so adjusted that there is no longer
an economic motive for migrating from the one to the other. If, in
order to determine what an absolutely static condition for the central
society would be, we were to apply the rule of imagining all new
dynamic influences precluded and of allowing time enough to elapse to
bring about a normal apportionment of population within that limited
area, we should encounter a measure of the same difficulty which
confronted us w