HOW THE SAME PEOPLES DIFFER
The Yakuts, who lead a nomad life in the valley of the Lena, and the Turks who govern Western Asia, are of the same stock, but the genial climate has enabled the Turks to flourish while the cold has kept the Yakuts poor. These groups represent both branches of the stock.
Considering the influence even of slighter differences in climate, the locations of regions of similar mean annual temperature, and the distances which separate them from one another, cannot be otherwise than important. A map on which the isothermal lines are drawn is rich in historical instruction. Where the lines diverge we have regions of equal temperature; where they crowd together, districts of different mean annual temperatures lie close to one another. The crowding of climatic variations in any region enlivens and hastens the course of history in that region. If the variations occur only at long intervals, all parts of a large territory having approximately equal mean annual temperatures, then climatic contrasts, which act as a ferment, as it were, are not present to any appreciable extent, and their effects lose in intensity and are dispelled.
Where are greater combinations of contrasting climatic elements to be found than in Greece and in the Alps? The joining together of the natives of rich, fruitful Zürich with the poor shepherds of the forests and mountains was of the utmost importance to the development of the Swiss Confederation. It was also a union of regions of mild and cold temperatures. The possession of Central European and Mediterranean climates, that shade into one another without any sharp line of demarcation, is a great advantage to France. If climatic differences approach one another in too great a contrast, clefts in development are likely to occur, such as the gap between the Northern and the Southern States in America, and that between North and South Queensland. If it be possible to adjust the political differences, then the union of areas of different temperatures has an invigorating effect, as shown by the history of the American Southern States since 1865.
THE EFFECTS OF CLIMATE ON THE POWER OF PEOPLES
There is a world of difference between the two branches of the Tunguse race: the one is a poor people living in cold regions and subject to Russia; the other is the ruling race of the Chinese Empire, flourishing in a temperate climate. The upper group is composed of ruling Tunguses in China and the lower group represents Tunguses subject to Russia.
Winds blowing in a constant direction for many months at a time were of great assistance to navigation during the days of sailing vessels, which, indeed, have not yet been entirely supplanted by steamships. Before the time of steam vessels all traffic on the Indian Ocean was closely connected with the change of the monsoons; and important political expansions have followed in the track of the same winds—for example, the diffusion of the Arabs along the east coast of Africa and in Madagascar. The influence of the trade winds on the Spanish and Portuguese discoveries along the Atlantic coast of America is well known. The south-eastern trade winds have been a cause of both voluntary and involuntary emigrations of Polynesian races. It may be clearly seen from the history of Greece what advantage was obtained by the race that won the alliance of the coast of Thrace and the wind that blows south from it with constancy during the entire fair season, often eight months long.