ed city of Lhassa
ensure China's control over the restless nomads through the
instrumentality of the Grand Lama of Tibet.

[Sidenote: Results of historical movement.]

Historical movements are varied as to motive, direction, numerical
strength, and character, but their final results are two,
differentiation and assimilation. Both are important phases of the
process of evolution, but the latter gains force with the progress of
history and the increase of the world's population.

[Sidenote: Differentiation and area.]

A people or race which, in its process of numerical growth, spreads over
a large territory subjects itself to a widening range of geographic
conditions, and therefore of differentiation. The broad expansion of the
Teutonic race in Europe, America, Australia and South Africa has brought
it into every variety of habitat. If the territory has a monotonous
relief like Russia, nevertheless, its mere extent involves diversity of
climate and location. The diversity of climate incident to large area
involves in turn different animal and plant life, different crops,
different economic activities. Even in lowlands the relief, geologic
structure, and soil are prone to vary over wide districts. The
monotonous surface of Holland shows such contrasts. So do the North
German lowlands; here the sandy barren flats of the "geest" alternate
with stretches of fertile silt deposited by the rivers or the sea,[212]
and support different types of communities, which have been admirably
described by Gustav Frenssen in his great novel of Joen Uhl. The flat
surface of southern Illinois shows in small compass the teeming
fertility of the famous "American bottom," the poor clay soil of "Egypt"
with its backward population, and the rich prairie land just to the
north with its prosperous and progressive farmer class.

When the relief includes mountains, the character not only of the land
but of the climate changes, and therewith the type of community. Hence
neighboring districts may produce strongly contrasted types of society.
Madison County of Kentucky, lying on the eastern margin of the Bluegrass
region, contains the rich landed estates, negro laboring class and
aristocratic society characteristic of the "planter" communities of the
old South; and only twenty miles southeast of Richmond, the center of
this wealth and refinement, it includes also the rough barren hill
country of the Cumberland Plateau, where are found one-room cabin