272 The Ajstdes and the Amazon. 



Andes. Wlaile the Arkansas joins the Mississippi four 

 hundred miles above New Orleans, the Madeira, of equal 

 length, enters the Amazon nine hundred miles from Para. 

 But, vast as are these tributary streams, they seem to make 

 no impression on the Amazon ; they are lost like brooks in 

 the ocean. Our ideas of the magnitude of the great river 

 are wonderfully increased when we see the Madeira com- 

 ing down two thousand miles, yet its enormous contribu- 

 tion imperceptible half way across the giant river ; or the 

 dark waters of the Negro creeping along the shore, and 

 becoming undistinguishable five miles from its mouth. 

 Though the Amazon carries a larger amount of sediment 

 than any other river, it has no true delta, the archipelago 

 in its mouth (for, like our own St. Lawrence, it has its Bay 

 of a Thousand Isles) not being an alluvial formation, but 

 having a rocky base. The great island of Marajo, in phys- 

 ical configuration, resembles the mainland of Guiana. The 

 deltoid outlet is confined to the tributaries, nearly all of 

 them, like " the disemboguing Nile," emptying themselves 

 by innumerable embouchm-es. To several tributaries the 

 Amazon gives water before it receives their tribute. Thus, 

 by ascending the Negro sixty miles, we have the singular 

 spectacle of water pouring in from the Amazon through 

 the Guariba Channel. 



The waters of this great river system are of divers tints. 

 The Amazon, as it leaps from the Andes, and as far down 

 as the Ucayali, is blue, passing into a clear olive-green ; 

 likewise the Pastassa, Huallaga, Tapajos, Xingii, and To- 

 cantms. Below the Ucayali it is of a pale, yellowish olive ; 

 the Madeira," Purus, Jurua, Jutahi, Javari, Ucayali, Napo, 

 19a, and Japura are of similar color. The Negro, Coary, 

 and Teffe are black. Humboldt observes that " a cooler 



* The Madeira has often a milky color which it receives from the white 

 clay along its banks. 



