248 Dependence of the Geographical Belations of Countries 



beds become narrower, their course becomes less rapid, and 

 the process of evaporation loses in energy ; so that we may lay 

 it down as an axiom, that, the more populous a country, and 

 the longer inhabited, the more deficient it will be in forests, 

 springs, and rivers ; again, the more recently and the more 

 thinly peopled, the greater will be the amount of forests and 

 flowing waters. 



Tartary, Persia, and many other countries of Asia ; also Spain, 

 Italy, and Greece, attest the circumstance, that a scarcity of 

 forests involves a scarcity of water, and that the bare and bleak 

 condition of the mountains, constitutes the reason why their 

 declivities are without springs, and their valleys without rivers. 

 The highlands of Central Asia possess neither forests nor 

 flowing waters ; small brooks are by heavy showers swollen 

 into torrents, which carry the mould from the fields to the 

 valleys, lay waste the fertile districts, and inundate their crops. 

 The United States of North America present relations ma- 

 terially different. They contain immense forests and systems 

 of vastly expanded lakes and rivers, which partly facilitate, 

 partly impede, the geographical development of these coun- 

 tries ; they prove, moreover, that the extent of forests is uni- 

 formly proportional to the amount of flowing and standing 

 waters. Comparative geography informs us, that mountain- 

 ous, and at the same time woody countries, are amply provided 

 with water ; that the clearing of forests causes the springs and 

 brooks to dry up, and rivers to sink below their ordinary level, 

 so that their beds and channels are finally blocked up with 

 sand and mud, and rendered useless for navigation ; that the 

 irrigation of fields depends on the extent of forests, covering 

 the slopes and summits of mountains ; again, that forests con- 

 tribute to the expansion of navigable waters, put a stop to the 

 pernicious effects of aridity, and keep the ground in a state of 

 moisture and productiveness ; finally, that the countries in the 

 south of Europe, Spain, Italy, and Greece, in consequence of 

 the clearing of forests, witnessed the drying up of their springs 

 and streamlets, the almost total annihilation of their rivers, 

 and the transformation of their soil into comparatively barren 

 regions, so that the development of every geographical rela- 

 tion became seriously affected. 



