hat great exodus and displacement of
peoples known as the _Voelkerwanderung_, and thus contributed to the
downfall of Rome; it was one factor in the Saxon conquest of Britain and
the final peopling of central Europe. The impact of the Turkish hordes
hurling themselves against the defenses of Constantinople in 1453 was
felt only forty years afterward by the far-off shores of savage America.
Earlier still it reached England as the revival of learning, and it gave
Portugal a shock which started its navigators towards the Cape of Good
Hope in their search for a sea route to India. The history of South
Africa is intimately connected with the Isthmus of Suez. It owes its
Portuguese, Dutch, and English populations to that barrier on the
Mediterranean pathway to the Orient; its importance as a way station on
the outside route to India fluctuates with every crisis in the history
of Suez.

[Sidenote: Direct and indirect effects of environment.]

The geographic factors in history appear now as conspicuous direct
effects of environment, such as the forest warfare of the American
Indian or the irrigation works of the Pueblo tribes, now as a group of
indirect effects, operating through the economic, social and political
activities of a people. These remoter secondary results are often of
supreme importance; they are the ones which give the final stamp to the
national temperament and character, and yet in them the causal
connection between environment and development is far from obvious. They
have, therefore, presented pitfalls to the precipitate theorizer. He has
either interpreted them as the direct effect of some geographic cause
from which they were wholly divorced and thus arrived at conclusions
which further investigation failed to sustain; or seeing no direct and
obvious connection, he has denied the possibility of a generalization.

Montesquieu ascribes the immutability of religion, manners, custom and
laws in India and other Oriental countries to their warm climate.[17]
Buckle attributes a highly wrought imagination and gross superstition to
all people, like those of India, living in the presence of great
mountains and vast plains, knowing Nature only in its overpowering
aspects, which excite the fancy and paralyze reason. He finds, on the
other hand, an early predominance of reason in the inhabitants of a
country like ancient Greece, where natural features are on a small
scale, more comprehensible, nearer the measure of ma