p has its
date. Those in the Statistical Atlas of the United States showing the
distribution of population from 1790 to 1890 embody a mass of history
as well as of geography. A map of France or the Russian Empire has a
long historical perspective; and on the other hand, without that map
no change of ethnic or political boundary, no modification in routes
of communication, no system of frontier defences or of colonization,
no scheme of territorial aggrandizement can be understood.

[Sidenote: Multiplicity of geographic factors.]

The study of physical environment as a factor in history was
unfortunately brought into disrepute by extravagant and ill-founded
generalization, before it became the object of investigation according
to modern scientific methods. And even to-day principles advanced in the
name of anthropo-geography are often superficial, inaccurate, based upon
a body of data too limited as to space and time, or couched in terms of
unqualified statement which exposes them to criticism or refutation.
Investigators in this field, moreover, are prone to get a squint in
their eye that makes them see one geographic factor to the exclusion of
the rest; whereas it belongs to the very nature of physical environment
to combine a whole group of influences, working all at the same time
under the law of the resolution of forces. In this plexus of influences,
some operate in one direction and some in another; now one loses its
beneficent effect like a medicine long used or a garment outgrown;
another waxes in power, reinforced by a new geographic factor which has
been released from dormancy by the expansion of the known world, or the
progress of invention and of human development.

[Sidenote: Evolution of geographic relations.]

These complex geographic influences cannot be analyzed and their
strength estimated except from the standpoint of evolution. That is one
reason these half-baked geographic principles rest heavy on our mental
digestion. They have been formulated without reference to the
all-important fact that the geographical relations of man, like his
social and political organization, are subject to the law of
development. Just as the embryo state found in the primitive Saxon tribe
has passed through many phases in attaining the political character of
the present British Empire, so every stage in this maturing growth has
been accompanied or even preceded by a steady evolution of the
geographic relations of the E