82,000 square leagues, are without the Tropics, or under the temperate zone. The whole extent of the Republic is equal to one-fourth of Europe, or to France, Austria, Spain, Portugal, and Great Britain, put together; and the difference of latitude alone, on so enormous a surface, would naturally have the effect of causing considerable changes in the temperature of the more distant points.
It is not, however, to this circumstance, so much as to the peculiarity of its geological structure, that Mexico owes that singular variety of climate, by which it is distinguished from most other countries of the world.
To this I must call the particular attention of my readers, as, without a right understanding of its causes, a great part of the present sketch would prove unintelligible.
The Cordillera of the Andes, after traversing the whole of South America and the Isthmus of Panama, separates into two branches on entering the Northern continent, which, diverging to the East and West, but still preserving their direction towards the North, leave in the centre an immense platform, or Table-land, intersected by the higher points and ridges of the great mountain chain by which it is supported, but raised, in the more central parts, to the enormous height of seven thousand feet above the level of the sea.
This elevation it loses, in part, on its approach
