Ill CLIMATE AND VEGETATION 49 



dry, is not so in any excessive degree. ^ We see nearly the 

 whole of Australia covered by lofty trees, yet that country 

 possesses a far more arid climate. Hence we must look to 

 some other and unknown cause. 



Confining our view to South America, we should certainly 

 be tempted to believe that trees flourished only under a very 

 humid climate ; for the limit of the forest-land follows, in a 

 most remarkable manner, that of the damp winds. In the 

 southern part of the continent, where the western gales, charged 

 with moisture from the Pacific, prevail, every island on the 

 broken west coast, from lat. 38° to the extreme point of Tierra 

 del Fuego, is densely covered by impenetrable forests. On the 

 eastern side of the Cordillera, over the same extent of latitude, 

 where a blue sky and a fine climate prove that the atmosphere 

 has been deprived of its moisture by passing over the mountains, 

 the arid plains of Patagonia support a most scanty vegetation. 

 In the more northern parts of the continent, within the limits 

 of the constant south-eastern trade wind, the eastern side is 

 ornamented by magnificent forests ; whilst the western coast, 

 from lat. 4° S. to lat. 32° S., may be described as a desert : on 

 this western coast, northward of lat 4° Su,where the trade wind 

 loses its regularity, and heavy torrents of rain, fall periodically, 

 the shores of the Pacific, so utterly desert in Peru, assume near 

 Cape Blanco the character of luxuriance so celebrated at 

 Guayaquil and Panama. Hence in the southern and northern 

 parts of the continent, the forest and desert lands occupy 

 reversed positions with respect to the Cordillera, and these posi- 

 tions are apparently determined by the direction of the prevalent 

 winds. In the middle of the continent there is a broad 

 intermediate band, including central Chile and the provinces of 

 La Plata, where the rain-bringing winds have not to pass over 

 lofty mountains, and where the land is neither a desert nor 

 covered by forests. But even the rule, if confined to South 

 America, of trees flourishing only in a climate rendered humid 

 by rain-bearing winds, has a strongly-marked exception in the 

 case of the Falkland Islands. These islands, situated in the 

 same latitude with Tierra del Fuego and only between two and 

 three hundred miles distant from it, having a nearly similar 



1 Azara says, *' Je crois que la quantite annuelle des pluies est, dans toutes ces 

 con trees, plus considerable qu'en Espagne." — Vol. i. p. 36. 



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