Geologists are rapidly becoming convinced that the mammals spread from their central Asian point of origin largely because of great variations in climate.

Man could not stay there forever. He was bound to spread to new regions, partly because of his innate migratory tendency and partly because of Nature's stern urgency.

We are learning, too, that the love of beauty is one of Nature's greatest healers.

Although farming of any sort was almost as impossible in the plains as in the dry regions of winter rains farther west, the abundance of buffaloes made life much easier in many respects.

As a matter of fact, an ordinary desert supports a much greater variety of plants than does either a forest or a prairie.

A journey of four hundred and thirty miles can be made in any part of the United States, but in Turkey it takes as many days.

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.