EAINS AND Bn'ERS. 101 



rivers that we shall treat as rain-gauges ; and there are only ten 

 in the world whose valleys include an area of more than 500,000 

 square miles. They are : 



Square mileg. 



The Amazon, including the Tocantines and Orinoco . 2, 048, 000 



Mississippi 982,000 



La Plata] 886,000 



Yenisei ,. . . 785,000 



Obi 725,000 



Lena 594,000 



Amoor 583,000 



Yang-tse-kiang 548,000 



Hoang-ho 537,000 



Nile 520,000 



These areas are stated in round numbers, and according to the 

 best authorities. The basin of the Amazon is usually computed at 

 1,512,000 square miles ; but such computation excludes the 

 Tocantines, 204,000 square miles, which joins the Amazon near 

 its mouth, and the Orinoco, v;ith a hydrographic area of 252,000 

 square miles, which, by means of the Casiquiare, is connected also 

 with the Amazon. We think that these three rivers should all 

 be regarded as belonging to one hydrographic basin, for a canoe 

 may pass inland from any one to either of the others without 

 portage. Of these hydrographic basins, three, including an area 

 of 3,916,000 square miles, are American; six, which contain an 

 area of 3,772,000 square miles, belong to Asia, one to Africa, and 

 none to Europe. The three largest rivers of Asia, the Yenisei, 

 Obi, and Lena (2,104,000 square miles), discharge their waters 

 into the Arctic Ocean ; their outlets are beyond the reach of the 

 commercial world ; consequently they do not possess the interest 

 which, in the minds of men generally, is attached to the rest. The 

 three others of Asia drain 1,668,000 square miles, and run into 

 the Pacific ; while the whole American system feed with their 

 waters and their commerce the Atlantic Ocean. These rivers, 

 with their springs, give drink to man and beast, and noiu-ish with 

 their waters plants and reptiles, with fish and fowl not a few. 

 The capacity of their basins for production and wealth is without 

 limits. These streams are the great arteries of inland commerce. 

 Were they to dry up, political communities would be torn asunder, 

 the harmonies of the earth would be destroyed, and that beautiful 

 adaptation of physical forces to terrestrial machinery, by which 

 climates are regulated, would lose its adjustment, and the seasons, 

 would run wild, hke a watch without a balance. 



