of the sea.

The influence of geographical position

is absorbed in the effect of this elevation.

There are only two seasons known in the equinoctial region of Mexico even as far as the 28th degree of N. latitude; the rainy season (estacion de las aguas), which begins in the month of June or July, and ends in the month of September or October, and the dry season (el estio), which lasts eight months, from October to the end of May. The first rains generally commence on the eastern declivity of the Cordillera. The formation of the clouds, and the precipitation of the water dissolved in the air, commence on the coast of Vera Cruz. These phenomena are accompanied with strong electrical explosions, which take place successively at Mexico, Guadalaxara, and on the western coast. The chemical action is propagated from east to west in the direction of the trade winds, and the rains begin fifteen or twenty days sooner at Vera Cruz than on the central table-land. Sometimes we see in the mountain, even below 6600 feet of absolute height, rain mixed with hail (gresil) and snow in the months of November, December, and January; but these rains are very short, and only last from four to five days; and, however cold they may be, they are considered as very beneficial to the wheat and pasture lands. In Mexico, as in Europe, the rains are most frequent in the mountainous regions, especially in that part of the Cordilleras which extends from the Pic d'Orizaba by Guanaxuato,

Sierra de Pinos, Zacatecas, and Bolaños, to the mines of Guarisamey and the Rosario.

To the north of 20°, from the 22d to the 30th degree of latitude, the rains, which fall only in the months of June, July, August, and September, are very unfrequent in the interior of the country.

The aridity of the central plain, the want of trees, occasioned, perhaps, in a good measure by the length of time the great valleys have remained covered with water, obstruct very much the working of the mines. These disadvantages have augmented since the arrival of Europeans in Mexico, who have not only destroyed without planting, but in draining great tracts of land have occasioned another more important evil. Muriate of soda and lime, nitrate of potash, and other saline substances, cover the surface of the soil, and spread with a rapidity very difficult to be explained. Through this abundance of salt, and these efflorescences, hostile to cultivation, the table-land of Mexico bears a great resemblance in many places to Thibet and the saline steppes of central Asia. In the valley of Tenochtitlan particularly, the sterility and want of vi gorous vegetation have been sensibly augmenting since the Spanish conquest; for this valley was adorned with beautiful verdure when the lake occupied more ground, and the clayey soil was washed by more frequent inundations.

Happily, however, this aridity of soil, of which we have been indicating the principal physical causes,

GENERAL SALUBRITY.

47

is only to be found in the most elevated plains. A great part of the vast kingdom of New Spain may be ranked among the most fertile regions of the earth. The declivity of the Cordillera is exposed to humid winds and frequent fogs; and the vegetation nourished by these aqueous vapours exhibits an uncommon beauty and strength. The humidity of the coasts, assisting the putrefaction of a great mass of organic substances, gives rise to maladies, to which Europeans and others not seasoned to the climate are alone exposed; for under the burning sun of the tropics the unhealthiness of the air almost always indicates extraordinary fertility of soil. Thus at Vera Cruz the quantity of rain in a year amounts to 63 inches, while in France it scarcely amounts to 31 inches. Yet with the exception of a few sea-ports and deep valleys, where the natives suffer from intermittent fevers, New Spain must be considered as a remarkably healthy country.

In hot but dry climates the human species enjoys a longevity perhaps greater than what we observe in the temperate zones. This is especially the case whenever the temperature and climate are very variable. The Europeans who settle in the equinoctial part of the Spanish colonies at an advanced period of life, generally live and enjoy health to a great age. At Vera Cruz, in the midst of the epidemical black vomit, the natives and strangers seasoned for several years to the climate enjoy the most perfect health.

In general, the coasts and arid plains of equato

rial America, must be regarded as healthy, notwithstanding the excessive heat of the sun, whose perpendicular rays are reflected by the soil. Individuals arrived at maturity, particularly those who approach to old age, have little to fear from these regions, the unhealthiness of which has been unjustifiably exaggerated. The chief mortality is among the children and young people, particularly in those parts where the climate is at once hot and moist.

The inhabitants of Mexico are less disturbed by earthquakes and volcanic eruptions than those of Quito and the provinces of Guatimala and Cumana. There are only five burning volcanoes in all New Spain, Orizaba, Popocatepetl, and the mountains of Tustla, Jorullo, and Colima. Earthquakes, however, are by no means rare on the coast of the Pacific Ocean, and in the environs of the capital, but they never produce such desolating effects as have been experienced in the more southern provinces.

A very serious inconvenience is common to the eastern coast, and to the coast washed by the great ocean falsely called the Pacific Ocean. They are rendered inaccessible for several months by violent tempests, which effectually prevent all navigation. The north-west winds (los nortes) blow in the Gulf of Mexico from the autumnal to the spring equinox. These winds are generally moderate in the months of September and October; their greatest fury is in the month of March, and they sometimes last into April. Navigators who have long frequented the port of Vera

VARIETY OF CLIMATE.

49

Cruz, know the symptoms which always foretell the approach of the tempest.

An empire extending from the sixteenth to the thirty-seventh degree of latitude affords us, from its geometrical position, all the modifications of climate to be found on transporting ourselves from the banks of the Senegal to Spain, or from the Malabar coast to the steppes of the Great Bucharia. This variety of climate is also augmented by the geological constitution of the country, by the mass and extraordinary form of the Mexican mountains, which we have already described. On the ridge and declivity of the Cordilleras the temperature of each table-land varies as it is more or less elevated; not merely insulated peaks, the summits of which approach the region of perpetual snow, are covered with oaks and pines, but whole provinces spontaneously produce alpine plants; and the cultivator inhabiting the torrid zone frequently loses the hopes of his harvest from the effects of frost or from the abundance of snow.

Geographical position alone does not determine the nature of the productions of these fine regions. The union of several physical causes alluded to above, gives to a part of the equinoctial regions a temperature adapted to the cultivation of the wheat and fruit-trees of Europe. Latitude has small influence on the fertility of a country, where, on the summit and declivity of the mountains, nature exhibits an union of every climate.

H