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Physical aspect of the kingdom of New Spain compared with that of Europe and South America.-Inequalities of the soil.-Influence of these inequalities on the climate, cultivation, and military defence of the country.—State of the coasts.
We have hitherto considered the vast extent and the boundaries of the kingdom of New Spain. We have examined its relations with the other Spanish possessions, and the advantages which the configuration of its coasts afford for communications between the Atlantic and the South Seas. Let us now give a physical view of the country; and consider for a while the inequalities of its soil, and the influence of that inequality on the climate, cultivation, and military defence of Mexico. We shall merely exhibit general results. The details of natural history are foreign to statistics; but we cannot form an exact idea of the territorial wealth of a state, without knowing the structure of its mountains, the height of the great interior plains, and the temperature proper for those regions, in which the climates succeed, as it were, by strata, one above another. When we take a general view of the whole surface of Mexico, we see that one half is situated under the burning sky of the tropics, and the other belongs to the temperate zone. The latter contains 60,000 square leagues, and comprehends the provincias internas, both those which are under the immediate administration of the viceroy of Mexico (for example, the new kingdom of Leon, and the province of New Santander), and those governed by a particular commandant-general. The influence of this commandant extends over the intendancies of Durango and Sonora, and the provinces of Cohahuila, Texas, and New Mexico, regions thinly inhabited, which go all under the designation of provincias internas de la commendancia general, to distinguish them from the provincias internas del wireynato. On the one hand, small portions of the northern provinces of Sonora and New Santander pass the tropic of Cancer; and on the other, the southern intendancies of Guadalaxara, Zacatecas, and S. Luis de Potosi (particularly the environs of the celebrated mines of Catorce) extend a little to the north of this limit *. We know, however, that the physical climate of a country does not altogether depend on its distance from the pole, but also on its elevation above the level of the sea, proximity to the ocean, configuration, and a great number of other local circumstances, Hence, of
* There is an oversight in the original in this place; for the fact is literally the reverse. The northern provinces of Sonora and New Santander stretch as far north as 38°, and part of the southern intendancies of Guadalaxara, Zacatecas, and S. Luis de Potosi, lie south of the tropic of Cancer. Trans. VOL. I. O
the 50,000 square leagues situated in the torrid zone, more than three-fifths enjoy rather a cold or temperate than a burning climate. The whole interior of the viceroyalty of Mexico, especially the interior of the countries comprized under the antient denominations of Anahuac and Mechoacan, probably even all New Biscay, form an immense plain elevated 2000 or 2500 metres * above the level of the neighbouring seas. There is scarcely a point on the globe where the mountains exhibit so extraordinary a construction as in New Spain. In Europe, Switzerland, Savoy, and the Tyrol, are considered very elevated countries; but this opinion is merely founded on the aspect of the groups of a great number of summits perpetually covered with snow, and disposed in parallel chains to the great central chain. Thus the summits of the Alps rise to 3900 and even 4700 metrest, while the neighbouring plains in the canton of Berne are not more than from 400 to 600 feet in height. The former of these numbers (400), a very moderate elevation, may be considered as that of the most part of plains of any considerable extent in Suabia, Bavaria, and New Silesia, near the sources of the Wartha and Piliza. In Spain, the two Castilles are elevated more than 580 metres (300 toises) S. The highest level in France is Auvergne, on which the Mont d'Or, the Cantal, and the Puy de Dôme repose. The elevation of this level, according to the observations of M. de Buch, is 720 metres (370 toises) *. These examples serve to prove that in general the elevated surfaces of Europe which exhibit the aspect of plains, are seldom more than from 400 to 800, metrest (200 to 400 toises) higher than the level. of the ocean. - o
* 6561 and 8201 feet. Trans. + 12794 and 15419 feet. Trans. † 1312 and 1968 feet. Trans. § 1902 feet. Trans.
In Africa, perhaps, near the sources of thc. Nile i, and in Asia, under the 34" and 3,’ of north latitude, there are plains analogous to those, of Mexico; but the travellers who have visited Asia have left us completely ignorant of the elevation of Thibet. The elevation of the great desert. of Cobi, to the north-west of China, exceeds, accoiding to Father Duhalde, 1400 metres S. Colonel Gordon assured M. Labiliardiere, that from the Cape of Good Hope to the 2 ° of south latitude the soil of Africa rose gradually to 2000 metres | of elevation's. This fact, as new as: it is curious, has not been confirmed by other naturalists. . . . . . * .
The chain of mountains which form the vast
# 2360 feet. Trans. * From 1312 to 2024 feet. Trans. # According to Bruce (vol. iii. p. 642, 652, and 712), the sources of the Nile, in Gogam, are more than 3200 metres (10,500 feet) higher than the level of the Mediterranean. § 551 1 feet. Trans. || 6561 feet. Trans. * Labillardiere, t. i. p. 89.
plain of Mexico is the same with what, under the name of the Andes, runs through all South America; but the construction, I may say the skeleton, (Charpente) of this chain varies to the south and north of the equator. In the southern hemisphere, the Cordillera is every where torn and interrupted by crevices like open furrows not filled with heterogeneous substances. If there are plains elevated from 2700 to 3000 metres *(1400 to 1500 toises), as in the kingdom of Quito, and farther north in the province of los Pastos, they are not to be compared in extent with those of New Spain, and are rather to be considered as longitudinal vallies bounded by two branches of the great Cordillera of the Andes: while in Mexico it is the very ridge of the mountains which forms the plain, and it is the direction of the plain which designates as it were that of the whole chain. In Peru, the most elevated summits constitute the crest of the Andes; but in Mexico these same summits, less colossal it is true, but still from 4900 to 5400+ metres in height (2500 to 2770 toises), are either dispersed on the plain, or ranged in lines which bear no relation of parallelism with the direction of the Cordillera. Peru and the kingdom of New Grenada contain transversal vallies, of which the perpendicular depth is sometimes 1400; metres. The existence of these vallies prevents the inhabitants from tra
* From 10629 to 11811 feet. Trans. † From 16075 to 17715 feet, Trans, f 4854 feet. Trans.