1 7 o EVOLUTION OF THE EARTH 



Belgium and Finland are so cool that no entire month has 

 a mean temperature as high as the optimum. Stockholm 

 happens to show a low optimum, but this is not significant, for 

 accidental circumstances such as epidemics may cause the 

 figures for a single city to depart from the true normal. 4 



From the facts now before us it appears to make little 

 difference whether we are dealing with Finns of semi-Mongo- 

 loid stock in the Far North, with Nordics in central Europe 

 and America, with people of Mediterranean stock in southern 

 Italy and Sicily, or with Japanese in the Far East. In all 

 cases, the highest energy is found where the average tempera- 

 ture for day and night together is between 58 and 71 F. 

 In general it varies only a little above or below 64. It is 

 surprising enough to find such an agreement among all these 

 races of Europe and Asia. It is still more surprising to find 

 that in the United States the deaths of whites and of negroes, 

 so far as they are available in the figures of the United States 

 Census from 1912-1915, show essentially the same response. 

 This is illustrated in Figures 34 and 35. Figure 34 is based 

 on all the reported deaths of colored people from non- 

 contagious diseases in the states of Maryland, Virginia, 

 North Carolina, and Kentucky, together with all the cities, 

 both north and south, where deaths of negroes are reported in 

 the Census tables. The negro deaths number only 167,000, 

 or so few that accidental and local circumstances cause great 

 irregularities. Nevertheless, it is clearly evident that the zone 

 of fewest deaths ranges from about 53 to 78, which is essen- 

 tially the same as in Figures 31 to 33. Light areas indicating 

 many deaths are increasingly prominent at low temperatures 

 and low humidities, and also at high temperatures and high 

 humidities. 



Figure 35 is based on exactly the same places as Figure 34, 



4 For a further discussion of this subject see Huntington, Ellsworth, "Tem- 

 perature Optima for Human Energy." Proc. Nat. Acad. Sci., vol. 3, 1917, pp. 

 127-133. 



