664 THE UNIVERSE. 



charm of the perpetual movement of its waves. Here all 

 is lifeless and still. 



In other regions these great spaces, the surface of which 

 is only slightly irregular, are covered with a perfectly uni- 

 form vegetation ; one species rules there despotically, and 

 stifles all the others. Such is the spectacle presented by the 

 Landes of Bordeaux, exclusively pervaded by heath, which, 

 at the time of flowering, waves gently like a sea of purple, 

 whose waves, agitated by the breeze, melt away in the 

 azure of the distant horizon. 



Struck by the monotony of their steppes, thickly over- 

 grown by the humblest plants, the Mongols named them 

 the land of grass. But it is particularly in America, where 

 they bear the name of pampas, that they dismay the trav- 

 eller by their immense extent, and often by their impene- 

 trable nature. There, according to Humboldt, exist some 

 which occupy a space of 16,000 square leagues. 



Grasses and leguminous plants cover the surface as far as 

 the eye can see. In other places the steppe bristles with 

 tall thistles, which form impenetrable spiny barriers. 



The steppes of Southern America, being covered with a 

 light clothing of plants, and being periodically inundated 

 by torrents of rain, often present a luxuriant growth of 

 grasses. These solitudes are at such times traversed by 

 legions of animals, which there find water and an ample 

 supply of nourishment. 



But the scene changes so soon as the drought sets in. 

 Then death and aridity appear everywhere. The tropical 

 heat allows only a very ephemeral duration for this luxuri- 

 ant vegetation. When the heat of the sun is no longer 



