142 WORLD-POWER AND EVOLUTION 



that the ancestors of the Semites, of the Indo-Europeans who 

 dominated India, and of the Chinese and Japanese also dwelt in 

 this same general region. Thus although the matter is of course 

 uncertain, it seems probable that the world's most advanced 

 races all evolved under essentially the same climatic conditions. 

 The southern storm belt, in some part of which man apparently 

 took the last great steps in mental evolution, comprises all the 

 lands around the Mediterranean, the largest area of such lands 

 being in North Africa. It also includes the lands to the eastward 

 from Asia Minor to southern Turkestan, Persia, Afghanistan, 

 Baluchistan, and northern India. 



It is interesting to find that the climate of this region during 

 the Glacial Period was apparently much like that which we have 

 found to be most favorable to man's mental and physical activity. 

 In what follows it must be remembered that these conclusions as 

 to the climate and home of early man are only in a small degree 

 the work of the present author, and that they were framed before 

 any extensive studies had been made upon the exact nature of the 

 climate most stimulating to human activity. Hence their agree- 

 ment with the conclusions of earlier pages is made more striking. 

 Today the average January temperature of the regions where the 

 most intellectual races of mankind are supposed to have developed 

 ranges from 40 °F to 60". The July temperature averages from 

 75° to 85°. At the height of the last Glacial Epoch the mean 

 temperature of the earth as a whole is estimated by various 

 authors to have been 5" to 20 "F colder than at present. These 

 estimates are based on the height of the snowline as marked by 

 evidences of glaciation. Most authorities, especially those whol 

 have worked more recently, are inclined to say 8° to 12"* rather 

 than higher. Suppose we say 10°. Then the range of mean tem- 

 perature in the northern part of the area would have been from 

 about 30° in January to 65° in July, and in the southern part 

 from about 45° to 75°. This is essentially the same as prevails 

 today in the area from southern France northward to southern 



