CLIMATE OF MEXICO. 49 



of tlie mountain slopes, the force and direction of the winds, the distribution and 

 quantity of the rainfall. 



Nevertheless, in certain regions a uniform climate prevails over vast spaces. 

 Thus the northern states contain extensive plains remote from both oceans, where 

 the extremes of temperature characteristic of the American Far West are continued 

 far to the south on all those plateaux where the prevailing vegetation are the 

 cactus and thorny plants, which constitute a special zone combining the characters 

 of both zones. 



On the other hand the narrow region of the Tehuantepec isthmus belongs 

 entirely to the humid tropical zone, even on the mountains which form the divide 

 between the two oceans. The climatic contrasts caused by the different altitudes 

 are produced in a large way only in the central part of Mexico, on the Anahuac 

 plateau and the two border ranges. The route from Vera Cruz on the Atlantic, 

 across the plateau between the Puebla and Oaxaca uplands, and down to the 

 Pacific at Acapulco, is the highway where these sharply contrasted climates may 

 be studied to the best advantage. 



The low-lying maritime zone comprises both the swampy and unfertile sandy 

 coastlands, and the well-watered plains and first slopes which are thickly clad 

 with leafy trees intertwined with festoons of lianas and surmounted by the tufted 

 crests of tall palms. This is the tierra caliente, the "hot land," where the normal 

 temperature exceeds 74° F. Some places on the Mexican seaboard are in fact 

 amongst the hottest on the globe. Such is, for instance, the port of La Paz, which 

 earned for California the name of the " Hot Furnace " given to it by Cortes. 



Above the coast zones, one facing the Atlantic, the other the Pacific, follow 

 the tierras tem/)Iadas, or " temperate lands," comprised mainly between the 

 altitudes of 3,000 and 6,000 feet, but rising to a higher elevation in the southern 

 than in the northern states of the republic. These are the regions which corres- 

 pond to south-west Europe, at least in their mean temijerature, vegetable products 

 and suitability for settlement by the white race. 



The tierras templadas are succeeded by tbe tierras frias, or "cold lands," 

 which comprise the plateau proper with the encircling highlands. The less 

 elevated part of this region, growing maguey and cereals, is the most densely 

 peopled region in Mexico, whereas on the higher grounds, some of which rise 

 above the snow line, the climate is too rude to support a forest vegetation, or a 

 dense human population. Sometimes these higher grounds are grouped together 

 as a fourth zone distinguished by the name of tierras hchulas, or " frozen lands." 



In many parts special conditions have placed the different vegetable zones 

 in close proximity without any graduated transitions. From the summit of 

 certain headlands, occupied exclusively by plants of a European type, the traveller 

 sees at his feet palm groves and banana thickets. From the crests of the great 

 volcanoes all three zones may even be seen superimposed one above the other. 

 Thanks to the increased facilities for rapid travelling, it is now possible in a 

 single day to traverse the three distinct zones, which elsewhere are separated 

 one from the other by intervals of many hundreds and even thousands of miles. 

 37 



