12 



that's it ; 



over an area nearly double the 

 size of Great Britain; but the 

 whole of this is not absolutely 

 desolate. There are several 

 other deserts, but the Great 

 Sahara is the most desolate 

 - and parched waste upon the 

 globe. A material tract of land, 

 without any great elevations or 

 depressions upon its surface, con- 

 stitutes a plain. Plains differ in 

 accordance with their geographi- 

 cal situations, and other essen- 

 tials. Steppes are plains, or level 

 wastes, destitute of trees, in some 

 places covered with long rank 

 grass, in others, sandy and bar- 



i 



133. 



ren, 1. There are extensive 

 steppes in the south-western part 

 of Siberia. Steppes are interme- 

 diate in character between de- 

 serts and prairies. The latter are 



134. 



verdant plains, which form one 

 of the distinguishing features 



of North American scenery, 2. 

 They are of vast extent, and 

 though destitute of trees, except 

 in particular regions" and in the 

 localities of rivers, they are co- 

 vered with luxuriant grass, wild 

 flowers, and are inhabited by wild 

 animals. Here the American In- 

 dian finds herds of bison (Bos 

 Americanus), 2. In South Ame- 

 rica the lanos, or savannahs, are 

 great plains, similar to the prai- 

 ries of North America, 2 a ; but 



135. 



during the dry season their ve- 

 getation is entirely destroyed, 

 and the ground opens in crevices. 



Humboldt thus describes the appearance of 

 these withered savannahs, or, as he terms them, 

 South American steppes: — "When under the 

 vertical rays of the never-clouded sun, the 

 turfy covering falls into dust, the indurated 

 soil cracks asunder, as if from the shock of an 

 earthquake. If at' such times two opposing 

 currents of air, whose conflict produces a rota- 

 tory motion, come in contact with the soil, the 

 plain assumes a strange and singular aspect. 

 Like conical clouds, the points of which descend 

 to the earth, the sand rises through the rarefied 

 air, in the electrically charged centre of the 

 whirling current, resembling the loud water- 

 spout dreaded by the experienced mariner. 

 The lowering sky sheds a aim, almost coloured 

 light, on the desolate plain. The horizon 

 draws suddenly nearer, the steppe seems to 

 contract, and with it the heart of the wanderer. 

 The hot dusty particles which fill the air in- 

 crease the suffocating heat, and the wind, blow- 

 ing over the long-heated soil, brings with it no 

 refreshment, but rather a still more burning 

 giow. The pools gradually disappear, and 

 under the influence of the parching drought, 

 the crocodile and the boa become motionless, 

 and fall asleep, deeply buried in the dried 

 mud." 



