47 8 RELATION TO ENVIRONMENT. 



the Gulf and Middle Atlantic, yet it is still sufficient to support an abun- 

 dance of plant life. Thus it is seen that in general the interior of continents 

 is drier than the coast regions. 



927. In southern California, Lower California, and northern Mexico 

 the arid region extends to the Pacific, since the warmth of the land is not 

 sufficient to cause precipitation of the cooler air at this point. 



928. In Central America, northern, central, and eastern parts of South 

 America, the rainfall is very great. This constitutes the humid tropical 

 region of the western continents, which is noted for the luxuriance of its 

 vegetation. In much of the Amazon country the rainfall is over 80 

 inches. The prevailing winds are here from the very warmest part of 

 the Atlantic Ocean, which explains the exceptional precipitation in this 

 continental interior. West of the Andes mountain range it is dry. 



929. In Great Britain the warm Atlantic currents furnish warm, moist 

 winds which on the west coast give a precipitation of about 40 inches, 

 while in the cooler highlands it reaches 60 to 80 inches, and falls to 25 

 to 30 inches on the east coast. The latter is low for plants, but is ample 

 in such a cool climate as that of England. In southern Europe the rain- 

 fall is gradually less toward the interior of the continent. 



930. Much of Russia and Siberia is arid, especially northeast Russia 

 (the interior from east to west). The prevailing winds are from the cold 

 Arctic Ocean, which passing over a warmer land area, the moisture is 

 only slightly precipitated. In southern Siberia there is moderate rainfall. 



931. India and Burma are furnished with a high annual rainfall because 

 of their relation to the warm Indian Ocean to the south, from which the 

 prevailing winds sweep with great force from the southwest and are called 

 monsoons. These produce great rains over southern Asia to the Himalaya 

 Mountains, at which point most of the moisture has been precipitated. 

 In the delta region of the Ganges River the monsoon winds from the Indian 

 Ocean yield the highest precipitation, the annual rainfall being over 500 

 inches, or in one year over 800 inches, equals 67 feet. The luxuriance 

 of the vegetation of southern Asia is well known. On the other hand, 

 the high plains of Tibet and Central Asia just beyond the Himalayas are 

 arid, and have a desert vegetation. 



932. In eastern Asia there is a plentiful rainfall. In Japan the rainy 

 season extends from April to September, and at Tokio the annual rain- 

 fall is about 58 inches. In Korea it is 36 inches. Hongkong, farther 

 south, has a rainfall of 78 inches, while in the Philippine Islands and Dutch 

 East Indies the winds coming from the warm parts of the Pacific produce 

 great rainfall. 



93 . In Australia in the central west the precipitation is less than 5 

 inches; in the lower part of the interior it is about 10 inches; but is heavier 

 toward the east coast and over a small area on the southwest coast. 



