be found for human beings? Certain difficulties confront us in our search. As a rule each group of human beings prefers its own environment and questions the validity of the premises we are likely to accept. We pity the Eskimo but he does not envy us nor does he desire to live as we do. The Arab nomad sneers at our standards of achievement and prefers his own life. If we make achievement the basic factor in our scheme we are bound to find an answer which accounts for the success of the groups of men now dominant on earth. Recognizing these limitations and admitting the influence of nature on man, let us see what evidence can be found. Man has dwelt in all climes from the poles to the equator in all periods of time known to us. In most of them he has not only survived but has increased in numbers. Nevertheless, a little study will show that all of the great cultures of man have arisen in the temperate zones with some indication that man tends to press in to the colder rather than the warmer regions as he develops. There seem to be three or four possible causes for such a fact: (1) Nature may offer greater and more varied products needed by man in the temperate zones than elsewhere. (2) Disease may be more prevalent in certain regions. This is evident if one compares the polar regions with the tropics. (3) Certain climates may stimulate man to greater efforts than others. (4) Shifts in climate may account for the changes in location of man's civilizations. The last two points are the ones which concern us most. Huntington has studied the seasonal variations in health and energy of workers in Connecticut and Pennsylvania. The accompanying figure 13 illustrates the effects of weather not only on health but upon energy in general. The lower curves show the death rate in Connecticut (C) in Pennsylvania (D) from 1910 to 1913 among persons more than two years of age. The curves are inverted so that good health is indicated by high parts and poor health by de pressions. The two upper curves show the average hourly earnings of piece workers in three Connecticut factories (4) and in a huge Pittsburgh factory (B) during the same period. Notice how nearly the four curves vary in harmony. Follow the curves through the four years. Without exception they are low in winter. In the summer of 1911, which was extremely hot and trying, especially in New England, they all show a dip, while in the summers of 1912, and especially 1913, when the hot spells were short and well separated, the heat had FIG. I. SEASONAL VARIATIONS IN HEALTH AND ENERGY IN CON NECTICUT AND PENNSYLVANIA Work of factory operatives in (A) Connecticut and (B) Pennsylvania; health (death rate inverted) in (C) Connecticut and (D) Pennsylvania. Scale for A on left and C on right; B and D are placed below the others for convenience, though really belonging at essentially the same level. (From Huntington and Williams, Business Geography, John Wiley and Sons.) almost no effect. In the late autumn the curves for health drop sooner than those for energy, which seems to mean that the approach of cold weather at first stimulates people who are in good health while those who are feeble feel an ill effect from the low temperature more promptly. In winter, however, a drop in energy is regularly followed by a long period of poor health. The four curves fluctuate so closely together that they seem to be subject to the same influences. The four factories were engaged in different kinds of work; there were no strikes, labor troubles, or shut-downs to cause fluctuations in any of them; and the cities of Connecticut are 400 miles from Pittsburgh. There were no epidemics of any importance to cause the curves of health to go up and down together, and the agreement would be equally great if all contagious diseases were omitted. The only factor which seems competent to explain the curves and which varies approximately, though not exactly, the same way in both places is the seasons and the general character of the weather.14 Huntington has studied several thousand workers in factories from Connecticut to Florida and some seventeen hundred students in the schools at West Point and Annapolis and his findings are in close agreement with those of the Bureau of Mines and the health departments of various cities. He found that when it was very cold out of doors the activities of all groups were lessened. All groups were most active when the average temperature was from 60° to 65° F. with the noon temperature at 70° or over. Mental activity reached its maximum when the outside temperature averaged about 38°, that is, with frosts at night. Even temperature was not favorable and the best work was done when there was some daily change, but sudden and violent changes were not beneficial. Moderate changes with frequent cooling of the air gave the best results. There was a marked reduction of work in very dry weather and more work was done on cloudy than on bright days. Huntington and Williams summarize the optimum condition as "an average temperature of 64 and an average relative humidity of 80 per cent" which would together mean a daytime temperature of 66° to 70° and a relative humidity of 50 to 70 per cent. Huntington believes that the most important climatic factors are (1) the mean temperature, month by month, (2) the amount of change from day to day, and (3) the relative humidity. He then proceeds to map the world to discover where the best climatic conditions are found, that is, where the greatest human energy will be developed if men elsewhere do what they have done in the factories studied. He finds five such areas: (1) western and central Europe to the borders of Roumania and Northern Italy, (2) North America east of the Rockies from southern Canada to the thirty-eighth parallel, (3) the Pacific coast, (4) Japan, (5) New Zealand and the adjacent corner of Australia. Is it mere chance that these are the seats of the most progressive civilizations of to-day? It is well known that climate has changed over vast sections of earth, indeed may be ever changing. The deserts of Gobi and of Sahara show evidence of having had streams and human inhabitants at some past time. The ruins of irrigation ditches in our own arid Southwest indicate a population impossible with present supply of water. More than any other living man Huntington has studied this question and has traveled widely in quest of evidence. He is far from claiming as asserted by some of his critics that "history is nothing but a matter of geography" but he has given careful attention to the influence of climate on history and his opinions deserve consideration. ... Since most regions where civilization was once high but has now greatly decayed show signs of adverse climatic changes it seems that the relation of climate and civilization was probably the same in the past as at present. That is, climate appears to be the main factor in determining the broad general outlines of the distribution of health, energy, civilization, and productivity. But, on the other hand, relief, soils, minerals, and facilities for transportation, and likewise migration, natural selection, racial inheritance, parasitic diseases, food, clothing, shelter, occupations, density of population, and stage of culture introduce great modifications in the distribution which would result from climate alone. They lead to such features as the brilliancy of Athens in the past, the present remarkable development of Hawaii, and the contrast between the Black Belt and the Kentucky mountains. Yet climate still seems to remain the |