INFLUENCES OF ENVIRONMENT 139 



rainy Northwest, which resembles his native habitat, he 

 thrives both in body and estate." -" 



Besides tlic climatic gradations in temperature which 

 are round in diO'eront latitudes, there is climatic vari a- 

 tion in temperature correlated with altitude. There are 

 zones of latitude and zones of altitude.-^ ]\riss Sem- 

 ple tells us that the southern sloije of the Monte 

 Rosa Alps, from glacier cap at 4,500 meters to the banks 

 of the Po River, yields within certain limits a zonal epit- 

 ome of European life from Lapland to the ]\[editer- 

 ranean.-- Climate clianges with altitude in much the 

 same way as witli latitude. Generally speaking, heat 

 and absolute humidity diminish as height increases, while 

 rainfall becomes greater up to a certain level. "The 

 effect of ascending and descending currents of air is to 

 diminish the range of temperature on mountain slopes 

 and produce rather an oceanic type of climate. ' ' ^^ Uni- 

 form climate is usually found in a land of monotonous 

 relief, while a region rich in vertical articulations is rich 

 also in local varieties of climate. Plant and animal life 

 confomi to the climatic levels at different altitudes. 



''Central Asia has a threefold cultural stratification 



< 



of its population, eac]> attended by the appropriate den- 

 sity, according to location in steppe, piedmont and moun- 

 tain . The steppes have their scattered ])astoral nomads; 

 the piedmonts, with their_irrig'ation_streams, support 

 sedentary agricultural peoples, concentrated at focal 

 ]pornls"Tn commercial and industrial towns; the higher 

 reaches of the mountains are occupied by sparse groups 



20 ITuntin;itoii. IT. — "Cliaiifies of Climate and History." Amer. Hist. Re- 

 view, vol. IS. no. 2. .Ian. 191.3, ]>. 2:51. 

 -1 See fij;uro .")2. 

 -- Soniplo, o;). vit., p. 557. -^ Ibid., p. 55S. 



