In a climate where man needs little protection from the elements, where he may lie upon his back in the shade and with his bare toes pick wild growing fruit to nourish his body, one will find no great leaders in art, literature, science, statecraft, or industry; likewise, in the Arctic, where man simply gathers enough blubber to supply his animal wants and then burrows beneath the snows of fierce winters, one will not find leadership or creative genius. The regions of greatest human potential are limited to such portions of the temperate zone as have an abundance of rainfall, frequent changes in the weather, and an alluvial soil. In other words, the most perfect composite of human resourcefulness is found where nature is neither so fierce as to crush human aspiration, nor yet so gentle as to lull human desire. Humboldt says: “Man is the product of soil and climate; he is brother to the tree, the rocks, and the animals.” We shall endeavor to show that civilization and the greatest human potential follow the storm tracks of the world, and that climate is the most important factor in his environment, for without its proper adjustment to his needs the richest soil and the most beneficent form of government fail to bring out the best that is in him. Empire is determined as much by direction and force of the wind and changes in the weather as by the scheming of politicians, the deep-laid plans of diplomats, or the marshaling of battalions. The first thing that vigorous man requires is active atmospheric conditions and in his migrations he follows the climatic lines that appease his desires. A climate of little change between day and night and between winter and summer is soothing and at the same time deadening to the human faculties; but changes should be frequent rather than violent. The daring, the creative, the pioneering, the persistent spirits of mankind, like snow birds showering themselves with icy crystals, revel in the cool air, the perpetual oscillations of temperature, and the frequent changes from sunshine to cloud that pertain to the regions where storms are most numerous. Some days the mind works with a joyous lucidity, the spirits are high and the step elastic and vigorous. On another day the mind is turbid; it works slowly and hesitates in reaching decisions; one is listless and lacking in physical energy. On both days one may be in a perfectly normal physical and mental condition, except for the effects of the weather.