300 PLATFORMS OF THE ANDES. 



Great St. Bernard of the Swiss Alps ; and to deter- 

 mine this circumstance Humboldt executed five 

 laborious barometrical surveys, which enabled him 

 to construct a series of vertical sections of the 

 country. 



In South America the cordillera of the Andes pre- 

 sents plains completely level at immense altitudes, 

 such as that on which the city of Santa Fe de Bogota 

 stands, that of CaxamarcainPeru, and those of An- 

 tisana, which exceed in heig-ht the summit of the 

 Peak of Teneriffe. But all these levels are of small 

 extent, and being- separated by deep valleys are of 

 difficult access. In Mexico, on the other hand, vast 

 tracts of champaign country are so approximated to 

 each other as to form but a sing-le plain occupying 

 the elongated ridge of the cordillera, and miming 

 from the 18th to the 40th degree of north latitude. 

 The descent towards the coasts is by a graduated 

 series of terraces, which oppose great difficulties to 

 the communication between the maritime districts 

 and the interior, presenting at the same time an ex- 

 traordinary diversity of vegetation. 



The plains along the coasts are the only parts that 

 possess a climate adapted to the productions of the 

 West Indies, — the mean temperature of those situ- 

 ated within the tropics, and whose elevation does 

 not exceed 984 feet, being from 77° to 78-8=', which 

 is several degrees greater than the mean tempera- 

 ture of Naples. These fertile regions, which pro- 

 duce sugar, indigo, cotton, and bananas, are named 

 Tierras calicntes. Europeans reinaining in them for 

 any considerable time, particularly in the towns, are 

 liable to the yellow fever or black vomiting. On 

 the eastern shores the great heats are occasionally 

 tempered by strata of refrigerated air brought from 

 the north by the impetuous winds that blow from 

 October to March, which frequently cool the atmo- 

 sphere to such a degree, that at Havana the ther- 

 mometer descends to 32°, and at Vera Cruz to 608°. 



