294 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



vapour-springs for that valley to bo situated in the direction 

 supposed, the rising up of a continent from the bottom of the sea, 

 or the upheaval of a range of mountains in certain parts of 

 America, Africa, or Spain, across the route of the winds which 

 brought tlio rain for the Caspian water-shed, might have been 

 sufficient to i"ob them of the moisture which they were wont to 

 carry away and precipitate upon this great inland basin. See 

 how the Andes have made Atacama a desert, and of Western 

 Peru a rainless country : these regions have been made rainless 

 simply by the rising up of a mountain range between them and 

 the vapour-springs in the ocean which feed with moisture the 

 winds that blow over those now rainless regions. 



544. Countries in the temperate zone of this hemisphei'e that are 

 under the lee of land in the trade-wind regions of the other are dry 

 countries. — That part of Asia, then, which is under the lee of 

 southern trade-wind Africa, lies to the north of the tropic of 

 Cancer, and between two lines, the one passing through Cape 

 Palmas and Medina, the other through Aden and Delhi. Being 

 extended to the equator, they will include that part of it which 

 is crossed by the continental south-east trade-winds of Africa 

 after they have traversed the greatest extent of land surface 

 (Plate VII.). The range which lies between the two lines 

 which represent the course of the American winds with their 

 vapours, and the two lines which represent the course of the 

 African winds with their vapours, is the range which is under 

 the lee of winds that have, for the most part, traversed water 

 surface or the ocean in their circuit as south-east trade-winds. 

 But a bare inspection of Plate YII. will show that the south-east 

 trade-winds which cross the equator between longitude 15° 

 and 50° west, and which are supposed to blow over into this 

 nemisphere between these two ranges, have traversed land 

 as well as water ; and the Trade-wind Chart * shows that it 

 is precisely those winds which, in the summer and fall, are 

 converted into south-west monsoons for supplying the whole 

 extent of Guinea with rains to make rivers of. Those winds, 

 therefore, it would seem, leave much of their moisture behind 

 them, and pass along to their channels in the grand system 

 of circulation, for the most part, as dry winds. Moreover, it 

 is not to be supposed that the channels through which the winds 

 blow that cross the equator at the several places named are 

 * Series of Maury's Wind and Current Charts. 



