Page images

ally a soft spring temperature, which never varies more than four or five degrees (seven or nine of Fahrenheit). The extremes of heat and cold are there equally unknown. The natives give to this region the name of Tierras templadas, in which the mean heat of the whole year is from 20° to 210*. Such is the fine climate of Xalappa, Tasco, and Chilpansingo, three cities celebrated for their great salubrity, and the abundance of fruit trees which grow in their neighbourhood. Unfortunately, this mean height of 1300 metrest is the height to which the clouds ascend above the plains adjoining to the sea ; from which circumstance these temperate regions, situated on the declivity (for example, the environs of the city of Xalappa), are frequently enveloped in thick fogs.

It remains for us to speak of the third zone, known by the denomination of Tierras frias. It comprehends the plains elevated more than 22001 metres above the level of the ocean, of which the mean temperature is under 170g. In the capital of Mexico, the centigrade thermometer has been known to fall several degrees below the freezing point; but this is a very rare phenomenon ; and the winters are usually as mild there as at Naples. In the coldest season, the mean heat of the day is

* From 68° to 70° of Fahrenheit. Trans.
+ 4264 feet. Trans. 17217 feet. Trans.
9 62° of Fahrenheit. Trans,

from 13° to 140*. In summer the thermometer never rises in the shade above 24o7. The mean tenperature of the whole table-land of Mexico is in general 17° & which is equal to the temperature of Rome. Yet this same table-land, according to the classification of the natives, belongs, as we have already stated, to the Tierras frias; from which we may see that the expressions, hot or cold, have no absolute value. At Guayaquil, under a burning sky, the people of colour complain of excessive cold, when the centigrade ther. mometer suddenly sinks to 24°S, while it remains the rest of the day at 30°||.

But the plains more elevated than the valley of Mexico, for example, those whose absolute height exceeds 2500 metres , possess, within the tropics, a rude and disagreeable climate, even to an inhabitant of the north. Such are the plains of Toluca, and the heights of Guchilaque, where, during a great part of the day, the air never heats to more than 6° or go **, and the olive tree bears no fruit, though it is cultivated successfully a few hundred metres lower in the valley of Mexico.

All these regions called cold enjoy a mean temperature of from 11° to 13° tt, equal to that of

* From 55° to 70° of Fahrenheit. Trans. + 75° of Fahrenheit. Trans. 1 62° of Fahrenheit. Truns. $ 75° of Fahrenheit. Trans. Il 86° of Fahrenheit. Trans. 18201 feet. Trans. * * 43° or 46° of Fahrenheit. Trans. + + From 51° to 55° of Fahrenheit. Trans..

France and Lombardy. Yet the vegetation is less vigorous, and the European plants do not grow with the same rapidity as in their natal soil. The winters, at an elevation of 2500 metres, are not extremely rude; but the sun has not sufficient power in summer over the rarefied air of these plains to accelerate the development of flowers, and to bring fruits to perfect maturity. This constant equality, this want of a strong ephemeral heat, imprints a peculiar character on the climate of the higher equinoxial regions. Thus the cultivation of several vegetables succeeds worse on the ridge of the Mexican Cordilleras than in plains situated to the north of the tropic, though free quently the mean heat of these plains is less than that of the plains between the 19° and 22° of latitude.

These general considerations on the physical division of New Spain are extremely interesting in a political view. In France, even in the greatest part of Europe, the employment of the soil depends almost entirely on geographical latitude; but in the equinoxial regions of Peru, New Grenada, and Mexico, the climate, productions, aspect, I may say physiognomy, of the country, are solely modified by the elevation of the soil above the level of the sea. The influence of geographical position is absorbed in the effect of this elevation. Lines of cultivation similar to those drawn by Arthur Young and M. Decandolle on the hori

zontal projections of France can only be indicated on sections of New Spain. Under the 19o and 22° of latitude, sugar, cotton, particularly cacas and indigo, are only produced abundantly at an elevation of from 6 to 800* metres t. The wheat of Europe occupies a zone on the declivity of the mountains, which generally commences at 1400 metres, and ends at 3000 1 metres. The banana tree (musa paradisiaca), the fruit of which constitutes the principal nourishment of all the inhabitants of the tropics, bears almost no fruit above 1550 metres ; the oaks of Mexico grow only between 800 and 3000 metres ||; and the pines never descend towards the coast of Vera Cruz farther down than 1850 1, nor rise near the region of perpetual snow to an elevation of more than 4000 ** metres t t.

The provinces called internas, situated in the temperate zone (particularly those included be

* From 1968 to 2624 feet. Trans.

+ I speak here merely of the general distribution of the vegetable productions. I shall afterwards specify places where, favoured by a particular exposure, sugar and cotton may be cultivated 1700 metres (5576 feet) above the ocean.

4592 and 9842 feet. Trans. $ 5084 feet. Trans. Il Between 2624 and 9842 feet. Trans. $ 6068 feet. Trans.

** 13123 feet. Trans. ++ The reader may consult the section of the road from Mexico to Vera Cruz (plate VI.), and the agricultural scale in my essay on the geography of plants, p. 139.

tween the 30° and 38° of latitude, enjoy, like the rest of North America, a climate essentially different from that of the same parallels in the old continent. A remarkable inequality prevails between the temperature of the different seasons. German winters succeed to Neapolitan and Sicilian summers. It would be superflu us to assign here other causes for this phenomenon than the great breadth of the continent and its prolongation towards the north pole. This subject has been discussed by enlightened natural philosophers, particularly by M. Volney, in his excellent work on the soil and climate of the United States, with all the care which it deserves. I shall

I shall merely observe that the difference of temperature observable between the same latitudes of Europe and America, is much less remarkable in those parts of the new continent bordering on the Pacific Ocean than in the eastern parts.

M. Barton has proved, from the state of agriculture and the natural distribution of vegetables, that the Atlantic provinces are much colder than the extensive plains situated to the west of the Alleghiany mountains,

A remarkable advantage for the progress of national industry arises from the height at which nature, in New Spain, has deposited the precious metals. In Peru the most considerable silver mines, those of Potosi, Pasco, and Chota, are immensely elevated very near the region of perpetual snow. In working them, men, provisions,

« ՆախորդըՇարունակել »