and Nations on the extent and situation of Forests. 247 



to form an estimate of the breadth of their original beds ; the 

 Po furnished the alluvial soil for the plains of Lombardy ; the 

 Danube formerly filled a broad valley, and the mud of the 

 Mississippi gave origin to the boundless Savannahs of Louisi- 

 ana. The inferior and central course of rivers presents, there- 

 fore, a picture very different from that which formerly existed 

 and is still traceable in their superior course. Here vfQ find 

 mountains covered with snow and ice, or over-shadowed by 

 large forests, running parallel with the superior, and gene- 

 rally extending as far as the central course. The Rhone, 

 Rhine, Danube, Weser, Elbe, Maine, Neckar, and other rivers, 

 confirm this assertion, which is still more supported by an 

 examination of the sources of the Ganges, Dschumna, and 

 Buramputer, fed by the snows of the Himalayas, as also of 

 those of the Orinoco, Amazon, and La Plata, issuing from the 

 forests of the eastern Andes. 



At the same time that the forests on the northern slope of 

 Mount Atlas convey nourishment to a number of springs and 

 rivulets, and become thus the chief cause of fertilization, 

 aridity prevails on the southern slope, where the Sahara, with 

 its bleak and barren rocks of basalt, is close at hand. A similar 

 contrast may be traced between the eastern and western slope 

 of the Andes of South America. The former is covered with 

 extensive forests, giving rise to the sources of the Orinoco, the 

 Amazon, the Paraguay, and the Parana ; the latter, possessing 

 no forests, is destitute of lakes and rivers, owing to which the 

 western regions of Peru and Chili lie barren and waste. It 

 is impossible to attribute the cause of this to the mountains 

 from which those rivers draw their sources ; in that case, 

 neither the Volga, the largest river in Europe, which rises at 

 an elevation of scarcely 700 feet above its mouth, nor the Mis- 

 sissippi, which takes its origin on a bare mountain plain, could 

 carry with them masses of water as large as they do in reality. 



All the wild regions abound with rivers more numerous and 

 more copiously charged than those belonging to civilized coun- 

 tries. This diff^erence may be accounted for by the clearing of 

 forests, which causes the springs to dry up, and deprives the 

 rivulets, lakes, and marshes, of their nourishment. In conse- 

 quence, the larger rivers sink below their ordinary level, their 



