THE EARTH. 191 



heighten the scene. This is the sketch of an 

 African prospect, which delights the eye, even 

 while it destroys the constitution. 



Beside these annually periodical inundations, 

 there are many rivers that overflow at much 

 shorter intervals. Thus most of those in Peru 

 and Chili have scarcely any motion by night ; 

 but upon the appearance of the morning sun, 

 they resume their former rapidity : this proceeds 

 from the mountain snows, which, melting with 

 the heat, increase the stream, and continue to 

 drive on the current while the sun continues to 

 dissolve them. Some rivers also flow with an 

 even, steady current, from their source to the 

 sea ; others flow with greater rapidity, their 

 stream being poured down in a cataract, or swal- 

 lowed by the sands, before they reach the sea. 



The rivers of those countries that have been 

 least inhabited, are usually more rocky, uneven, 

 and broken into waterfalls or cataracts, than 

 those where the industry of man has been more 

 prevalent. Wherever man comes, nature puts on 

 a milder appearance : the terrible and the su- 

 blime are exchanged for the gentle and the use- 

 ful; the cataract is sloped away into a placid 

 stream ; and the banks become more smooth and 

 even.* It must have required ages to render 

 the Rhone or the Loire navigable ; their beds 

 must have been cleaned and directed ; their ine- 

 qualities removed ; and, by a long course of in- 

 dustry, nature must have been taught to conspire 



* Buflbn, vol. ii. p. 90. 

 is 



