economic and social life, and produce effects none the less important
because they are secondary. About these anthropo-geography can reach
surer conclusions than regarding direct psychical effects, because it
can trace their mode of operation as well as define the result. Direct
psychical effects are more matters of conjecture, whose causation is
asserted rather than proved. They seem to float in the air, detached
from the solid ground under foot, and are therefore subject matter for
the psychologist rather than the geographer.

[Sidenote: The great man in history.]

What of the great man in this geographical interpretation of history? It
seems to take no account of him, or to put him into the melting-pot with
the masses. Both are to some extent true. As a science,
anthropo-geography can deal only with large averages, and these exclude
or minimize the exceptional individual. Moreover, geographic conditions
which give this or that bent to a nation's purposes and determine its
aggregate activities have a similar effect upon the individual; but he
may institute a far-seeing policy, to whose wisdom only gradually is the
people awakened. The acts of the great man are rarely arbitrary or
artificial; he accelerates or retards the normal course of development,
but cannot turn it counter to the channels of natural conditions. As a
rule he is a product of the same forces that made his people. He moves
with them and is followed by them under a common impulse. Daniel Boone,
that picturesque figure leading the van of the westward movement over
the Allegheny Mountains, was born of his frontier environment and found
a multitude of his kind in that region of backwoods farms to follow him
into the wilderness. Thomas Jefferson of Virginia, in the Louisiana
Purchase, carried out the policy of expansion adumbrated in Governor
Spottswood's expedition with the Knights of the Golden Horseshoe over