ute-gatherer of the lower Lena River, or
the factor of the Hudson Bay Company. The assimilation tends to be
ethnic as well as economic, because the severity of the climate excludes
the white woman. The debilitating effects of heat and humidity, aided by
tropical diseases, soon reduce intruding peoples to the dead level of
economic inefficiency characteristic of the native races. These, as the
fittest, survive and tend to absorb the new-comers, pointing to
hybridization as the simplest solution of the problem of tropical
colonization.

[Sidenote: The relation of geography to history.]

The more the comparative method is applied to the study of
history--and this includes a comparison not only of different
countries, but also of successive epochs in the same country--the more
apparent becomes the influence of the soil in which humanity is
rooted, the more permanent and necessary is that influence seen to be.
Geography's claim to make scientific investigation of the physical
conditions of historical events is then vindicated. "Which was there
first, geography or history?" asks Kant. And then comes his answer:
"Geography lies at the basis of history." The two are inseparable.
History takes for its field of investigation human events in various
periods of time; anthropo-geography studies existence in various
regions of terrestrial space. But all historical development takes
place on the earth's surface, and therefore is more or less molded by
its geographic setting. Geography, to reach accurate conclusions, must
compare the operation of its factors in different historical periods
and at different stages of cultural development. It therefore regards
history in no small part as a succession of geographical factors
embodied in events. Back of Massachusetts' passionate abolition
movement, it sees the granite soil and boulder-strewn fields of New
England; back of the South's long fight for the maintenance of
slavery, it sees the rich plantations of tidewater Virginia and the
teeming fertility of the Mississippi bottom lands. This is the
significance of Herder's saying that "history is geography set into
motion." What is to-day a fact of geography becomes to-morrow a factor
of history. The two sciences cannot be held apart without doing
violence to both, without dismembering what is a natural, vital whole.
All historical problems ought to be studied geographically and all
geographic problems must be studied historically. Every ma