America forms the longest and straightest bone in the earth's skeleton.

Thus the races, though alike in their physical response to climate, may possibly be different in their mental response because they have approached America by different paths.

It will be a vast boon to mankind when we learn to prophesy the precise dates when cycles of various kinds will reach definite stages.

Fertile soil, level plains, easy passage across the mountains, coal, iron, and other metals imbedded in the rocks, and a stimulating climate, all shower their blessings upon man.

In fact, the history of North America has been perhaps more profoundly influenced by man's inheritance from his past homes than by the physical features of his present home.

Although mountains may guide migrations, the plains are the regions where people dwell in greatest numbers.

With every throb of the climatic pulse which we have felt in Central Asia,, the centre of civilisation has moved this way and that. Each throb has sent pain and decay to the lands whose day was done, life and vigour to those whose day was yet to be.