There is the direct influence of geographic conditions on man's constitution, causing what the biologists call modifications. Examples of these are the sluggishness induced by living in the tropics, the hardihood of mountaineers, the mental alertness of the peoples of the temperate zones. There is a book1 which attributes to climate a large share in determining the number of homicides in a country.

Everywhere a cold climate puts a steadying hand on the human heart and brain. It gives an autumn tinge to life. Among the folk of warmer lands eternal spring holds sway. National life and temperament have the buoyancy and thoughtlessness of childhood, its charm and its weakness. - Semple, Influences of Geographic Environment, p. 621.

There is the influence of diseases peculiar to climate, such as catarrh, malaria, and hookworm. Man can live in any climate on the earth when he becomes accustomed to it, and makes proper provision to cope with it; he is the most cosmopolitan of animals. The greatest difficulty seems to come when people from northern or temperate regions are being acclimated in the tropics. When any country opposes invaders who come from a different climate, one of its strong defenses is in the diseases and hardships peculiar to its climate.

Climate makes the calendar for outdoor occupations of all kinds, such as agriculture, fishing, traveling (other than by rail), and field sports. Through these it sets the seasons for much indoor work as well, fixing the time of stress and of vacation.

1 Morrison, Crime and its Causes.

Of more importance are the indirect influences of climate. First there are the social arrangements to which the foregoing direct influences lead. One of them is the political backwardness of tropical regions, involving at the present time the subjection of most of them to the states of the temperate zones. Montesquieu noted that the capital city of a country is best located in its northern part.

A warm and even climate makes it possible to exist at small cost in either money or labor; this favors abundant population and low wages - a point which Buckle makes much of. A cold climate is repressing to primitive peoples who have not learned how to cope with it; it keeps down their numbers, makes large states impossible, and prevents progress. But after the subtropical zone developed enough civilization to provide adequate shelter against the cold, and after the northern peoples had adopted civilization from the south, then life in the north became more comfortable than in the south, and the north took the lead in civilization. The varied seasons of the north give variety to life and require complicated social arrangements. The members of a family spend more of their time at home, thus fostering domestic life.

What matter how the night behaved? What matter how the north-wind raved? Blow high, blow low, not all its snow Could quench our hearth-fire's ruddy glow.

- Whittier, Snow-Bound.

The winter, when the soil cannot be worked and the nights are long, favors manufacturing and other forms of indoor work. Extreme changes in the weather have in recent years caused the science of meteorology to have a practical application in the work of the weather bureaus. This, of course, reacts upon the science and contributes powerfully to its further development. Finally, climate makes some places more desirable for residence than others. This leads to the partial segregation of the leisure classes, which in turn brings other consequences of importance.

Man grew in the temperate zone, was born in the Tropics. . . . Where man has remained in the Tropics, with few exceptions he has suffered arrested development. His nursery has kept him a child. Though his initial progress depended upon the gifts which Nature put into his hands, his later evolution depended far more upon the powers which she developed within him. These have no limit, so far as our experience shows, but their growth is painful, reluctant. Therefore they develop only where Nature subjects man to compulsion, forces him to earn his daily bread, and thereby something more than bread. . . .

Most of the ancient civilizations originated just within the mild but drier margin of the Temperate Zone, where the cooler air of a short winter acted like a tonic upon the energies relaxed by the lethargic atmosphere of the hot and humid Tropics; where congenial warmth encouraged vegetation, but where the irrigation necessary to secure abundant and regular crops called forth inventiveness, cooperation, and social organization, and gave to the people their first baptism of redemption from savagery to barbarism. . . .

As the Tropics have been the cradle of humanity, the Temperate Zone has been the cradle and school of civilization. Here Nature has given much by withholding much. Here man found his birthright, the privilege of struggle. - Semple, op. cit., pp. 634, 635.

. . . The hypothesis, briefly stated, is this: Today a certain peculiar type of climate prevails wherever civilization is high. In the past the same type seems to have prevailed wherever a great civilization arose. Therefore, such a climate seems to be a necessary condition of great progress. It is not the cause of civilization, for that lies infinitely deeper. Nor is it the only, or the most important condition. It is merely one of several, just as the abundant supply of pure water is one of the primary conditions of health. Good water will not make people healthy, nor will a favorable climate cause a stupid and degenerate race to rise to a high level. Nevertheless, if the water is bad, people cannot retain their health and strength, and similarly when the climate becomes unfit, no race can apparently retain its energy and progressiveness. ... - Huntington, Civilization and Climate, p. 9.