here of their new homes. Even Natal has not escaped
this soft impeachment. But the enterprise of colonials has cropped out,
under almost every condition of heat and cold, aridity and humidity, of
a habitat at sea-level and on high plateau. This blanket theory of
climate cannot, therefore, cover the case. Careful analysis supersedes
it by a whole group of geographic factors working directly and
indirectly. The first of these was the dividing ocean which, prior to
the introduction of cheap ocean transportation and bustling steerage
agents, made a basis of artificial selection. Then it was the man of
abundant energy who, cramped by the narrow environment of a Norwegian
farm or Irish bog, came over to America to take up a quarter-section of
prairie land or rise to the eminence of Boston police sergeant. The
Scotch immigrants in America who fought in the Civil War were nearly two
inches taller than the average in the home country.[24] But the ocean
barrier culled superior qualities of mind and character
also--independence of political and religious conviction, and the
courage of those convictions, whether found in royalist or Puritan,
Huguenot or English Catholic.

[Sidenote: Indirect effect through isolation.]

Such colonists in a remote country were necessarily few and could not be
readily reinforced from home. Their new and isolated geographical
environment favored variation. Heredity passed on the characteristics of
a small, highly selected group. The race was kept pure from intermixture
with the aborigines of the country, owing to the social and cultural
abyss which separated them, and to the steady withdrawal of the natives
before the advance of the whites. The homogeneity of island peoples
seems to indicate that individual variations are in time communicated by
heredity to a whole population under conditions of isolation; and in
this way modifications due to artificial selection and a changed
environment become widely spread.

Nor is this all. The modified type soon becomes established, because the
abundance of land at the disposal of the colonists and the consequent
better conditions of living encourage a rapid increase of population. A
second geographic factor of mere area here begins to operate. Ease in
gaining subsistence, the greater independence of the individual and the
family, emancipation from carking care, the hopeful attitude of mind
engendered by the consciousness of an almost unlimited opportunity and