GEOGRAPHICAL RELATIONS OF MEXICO. 299 



miles. The question of opening a communication 

 by a canal between the two oceans at this point, the 

 isthmus of Panama, or several others which he 

 mentions, is fully discussed by the author. He dis- 

 credits the idea that the level of the South Sea is 

 higher than that of the Gulf of Mexico, and imagines 

 that were a rupture of the intervening barrier ef- 

 fected, the current would establish itself in the di- 

 rection opposite to that usually apprehended. 



When a general view is taken of the whole sur- 

 face of Mexico, it is seen that one-half is situated 

 within the tropic, while the rest belongs to the tem- 

 perate zone. This latter portion contains 775,019 

 square miles. The physical climate of a countiy 

 does not altogether depend upon its distance from 

 the pole, but also upon its elevation, its proximity 

 to the ocean, and other circumstances ; so that of 

 the 645,850 square miles in the torrid zone, more 

 than three-fifths have a cold, or at least temperate 

 atmosphere. The whole interior of Mexico, in fact, 

 constitutes an immense table-land, having an eleva- 

 tion which varies from 6562 to 8202 feet above the 

 level of the sea. 



The chain of mountains which forms this vast 

 plain is continuous vvith the j^ndes of South Amer- 

 ica. In the southern hemisphere the cordillera is 

 everywhere broken up by fissures or valleys of small 

 breadth ; but in Mexico it is theridge itself that con- 

 stitutes the platform. In Peru the most elevated sum- 

 mits form the crest of the Andes, while in the other 

 the prominences are irregularly scattered over the 

 plain, and have no relation of parallelism to the di- 

 rection of the cordillera. In Peru and New- Grenada 

 there are transverse valleys, having sometimes 4590 

 feet of perpendicular depth, which entirely prevent 

 the use of carriages ; while in New-Spain vehicles 

 are used along an extent of more than 1726 miles. 

 Tlie general height of the table-land of Mexico is 

 equal to that of Mount Cenis, St. Gothard, or tlie 



