The South American Lowland. 115 



charged -nith moisture as those of the Amazon valley ; conse- 

 quently the thick forests and dense vegetation gradually disap- 

 pear, and, instead of an inland sea, there are vast plains or 

 pampas, over which roam herds that could not live in the valley 

 of the Amazon. Thus the difference in the rainfall changes the 

 entire vegetal and animal life. 



Through the center of South America, from the Caribbean sea to 

 the straits of Magellan, there is a vast stretch of lowland through 

 which run the waters of the Orinoco, Amazon and la Plata, 

 with low divides between their valle5^s. A boat can pass uj) the 

 Orinoco, thence by Cassiquiare river to the Rio Negro, a branch 

 of the Amazon, thence through the Amazon and its branches 

 to a low divide between the valleys of the Amazon and Rio de 

 la Plata. Here there is a carry of six or eight miles, and then 

 continuing down la Plata to the Atlantic ocean, the traveller may 

 make a water journey of over 3,000 miles between the Cordillera 

 and the eastern plains of South America. 



The easterly currents flowing from the Antarctic pole are de- 

 'flected by Cape Horn along both the eastern and western coasts 

 of Patagonia. On the eastern coast the winds blow off shore, 

 leaving that coast arid. The westerly current, as it approaches 

 the tropics, is deflected further westward and forms the greatest 

 of the equatorial currents. The moisture of the winds that 

 blow over this antarctic current is precipitated on the cool 

 shores of Patagonia and lower Chile, and these countries are 

 correspondingly enriched, while the same winds continuing 

 over the heated plains of upper Chile, Peru and southern Ecua- 

 dor are rarefied and take up what little moisture there is in 

 these plains, to be afterward condensed and precipitated on the 

 mountain slopes. 



From this cause the western coast of South America for the 

 3,000 miles from lower Chile to upper Ecuador is dr}^ and bar- 

 ren, and would be uninhabited except for the mines of gold and 

 silver in the mountains and the deposits of nitrates and guano 

 along the coast and on the islands. Yet the rainfall in South 

 America is greater than in anj^ other part of the world, and 

 more than twice as great as the rainfall in Asia. 



North America. 



The northern equatorial current, less powerful than the south- 

 ern, crosses the Pacific about the tropic of Cancer, where it is 



