2 ASIA 



and beneficial, while the outflowing winter winds are 

 dry and harmful. 



Again, according to their origin, the inflowing winds 

 produce unequal effects. Those called in from the 

 warm Indian and Pacific Oceans are naturally laden 

 with moisture which, on cooling, is condensed over the 

 southern and eastern margins of the continent, thus 

 inducing vigorous plant life. The air from the north 

 and east, on the other hand, easily saturated at low 

 temperatures, becomes gradually warmer and drier as 

 it rushes inland, yielding but scant moisture to the low- 

 lying plains and plateaus. A hardy but not luxuriant 

 type of vegetation is the expression of such climatic 

 conditions. 



Another inequality arises from the situation of the 

 neighbouring continents of Europe and Africa, which 

 screen off any moisture from the western quarters, while 

 the more favoured east lies open to the beneficial 

 influences of the oceans. Thus the arid centre extends 

 westward up to the uncertain borders of the adjacent 

 land masses. 



These broad features of the distribution of life on the 

 surface of Asia, by the accident of shape, size, and 

 position, are further emphasized by the nature of the 

 relief. The central portions are raised thousands of feet 

 above sea-level in vast plateaus which are fringed by 

 an unbroken rim of still loftier mountain ranges. On 

 that account, the excessive heating of the interior 

 exaggerates the landward influx of air in summer 

 while the intense cooling in winter adds impetus to the 

 outward flowing winds. The limits of the barren in- 

 terior are drawn more sharply by the screen of high 

 mountains surrounding them. At the same time, the 

 lofty ranges, such as those which cross the continent 



