8 VIEWS OF NATURE. 



Ocean, prodigious quantities of moisture, partly absorbed 

 and partly generated — all these causes produce in the flat 

 portions of America a climate which presents a most striking 

 contrast in point of humidity and coolness with that of Africa. 

 On these alone depend the luxuriant and exuberant vege- 

 tation and that richness of foliage which are so peculiarly 

 characteristic of the New Continent. 



If, therefore, the atmosphere on one side of our planet be 

 more humid than on the other, a consideration of the actual 

 condition of things will be sufficient to solve the problem of 

 this inequality. The natural philosopher need not shroud the 

 explanation of such phenomena in the garb of geological myths. 

 It is not necessary to assume that the destructive conflict 

 of the elements raged at different epochs in the eastern and 

 western hemispheres, during the early condition of our planet ; 

 or that America emerged subsequently to the other quarters 

 of the world from the chaotic covering of waters, as a swampy 

 island, the abode of crocodiles and serpents (19). 



South America presents indeed a remarkable similarity to 

 the south-western peninsula of the old continent, in the form 

 of its outlines and the direction of its coast -line. But the 

 internal structure of the soil, and its relative position with 

 respect to the contiguous masses of land, occasion in Africa 

 that remarkable aridity which over a vast area checks the 

 development of organic life. Four-fifths of South America lie 

 beyond the Equator, and therefore in a region which, on 

 account of its abundant waters, as well as from many other 

 causes, is cooler and moister than our northern hemisphere 

 (20). To this, nevertheless, the most considerable portion 

 of Africa belongs. 



The extent from east to west of the South American Steppes 

 cr Llanos, is only one third that of the African Desert. The 

 former are refreshed by the tropical sea wind, while the lat- 

 ter, situated in the same parallel of latitude as Arabia and 

 Southern Persia, are visited by currents of air which have 



