KELATIONS OF AIR AND WATER TO TEMPERATURE AND LIFE. 2G7 



to the ocean through the Orinoco, the Amazon, and la Phxta, and makes 

 the interior of South America one of the richest countries of the world. 



The Amazon, a great mediterranean sea, as it is often rightly called, 

 is projected into the heart of the continent. Its total fall from the 

 foothills of the Cordilleras to the ocean is not over 300 or 400 feet, 

 affording for the largest vessels uninterrupted navigation and innumer- 

 able harbors for 1,500 miles into the interior and 1,000 miles farther 

 for smaller vessels. The aggregate navigable waters of the main 

 stream and its tributaries are estimated at 50,000 miles. The moist 

 winds abundant!}- water the valley and modify its climate. Their influ- 

 ence in tempering the climate is felt directly more than 1,000 miles up 

 the valley, and indirectly still farther, through the sliadows thrown by 

 the clouds and through the rainfall and the cooling effect of the drops 

 of rain falling from a high altitude. It is from 8° to 10^" cooler than 

 on either side of this rain belt, and it is more healthful than other 

 equatorial regions. Tlie trojiical woods are so thick and the creepers 

 and undergrowth so luxuriant that animal life is almost entirely con- 

 fined to the trees above and the waters below. Nature has thus far 

 been more powerful than man, who has struggled in vain to subdue 

 this fertile valley to his use. 



The winds that pass up the valley of Rio de la Plata to the moun- 

 tains of Peru, Bolivia, and Argentina are not so heavily charged with 

 moisture as those of the Amazon Valley; consequently the thick for- 

 ests and dense vegetation gradually disappear, and, instead of an 

 inland sea, there are vast planis 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 Soutli 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 valleys. A boat can pass up the Orinoco, thence 

 by Cassiquiare River to the Rio jSTegro, a branch of the Amazon, thence 

 through the Amazon and its branches to a low divide between the val- 

 leys of the Amazon and Rio de la Plata. Here there is a carry of 6 or 

 8 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 Antartic i)ole are deflected by 

 Cape Horn along both the eastern and western coasts of Patagonia. 

 On the eastern coast the winds blow offshore, leaving that coast arid. 

 The westerly current, as it api)roaches the tropics, is deflected further 

 westward and forms the greatest of the equatorial currents. The mois- 

 ture 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 tlie same winds continuing over the 

 heated plains of upper Chile, Peru, and southern Ecuador are rarefied 



