Page images

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, Sa. voy, 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 metres t, while the neighbouring plains in the can ton 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 consis dered 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

* 6561 and 8201 feet. Trans. → 12794 and 15419 feet. Trans. | 1312 and 1968 feet. Trans. § 1902 feet. Trans. France is Auvergne, on which the Mont d'Or, the Cantal, and the Puy de Dôme repose. The elea vation 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 ele- : vated surfaces of Europe which exhibit the aspect of plains, are seldom more than from 400 to 800 metres † (200 to 400 toises) higher than the level of the ocean.

- In Africa, perhaps, near the sources of the Niles, and in Asia, under the 34 and 370 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 eleva. tion of Thibet. The elevation of the great desert of Cobi, to the north-west of China, exceeds, according to Father Duhalde, 1400 metres . Co. lonel Gordon assured M. Labillardiere, that from the Cape of Good Hope to the 2.0 of south latitude the soil of Africa rose gradually to 2000 metres || of elevation (. 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 2624 feet. Trans."

According to Bruce (vol. iii. p. 642, 052, and 712), the sources of the Nile, in Gogam, are more than 3200 metres (10,500 feet) higher than the level of the Mediterranean

§ 5511 feet. Trans. .. 6565 feet. Trane, I Labillardiere, t. i. p. 89. . und


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. velling except on horseback, a-foot, or carried on the shoulders of Indians (called cargadores); but in the kingdom of New Spain carriages roll on to Santa Fe in the province of New Mexico, for a length of more than 1000 kilometres or 500 leagues. On the whole of this road there were few difficulties for art to surmount.

* From 10629 to 11811 feet. Trans. + From 16075 to 17716 feet. Trans. | 4854 feet. Trans.

The table-land of Mexico is in general so little interrupted by vallies, and its declivity is so gentle, that as far as the city of Durango, in New Biscay, 140 leagues from Mexico, the surface is continually elevated from 1700 to 2700* metres above the level of the neighbouring ocean. This is equal to the height of Mount Cenis, St. Go thard, or the Great St. Bernard. That I might examine this geological phenomenon with the attention which it deserves, I executed five barometrical surveys. The first was across the kingdom of New Spain, from the South Sea to the Mexican Gulf, from Acapulco to Mexico, and from Mexico to Vera Cruz. The second survey extended from Mexico by Tula, Queretaro, and Salamanca to Guanaxuato. The third comprehended the intendancy of Valladolid, from Guanaxuato to the volcano of Jorullo at Pascuaro. The fourth extended from Valladolid to Toluca, and from thence to Mexico. Lastly, the fifth included the environs of Moran and Actopan. The number of points of which I determined the height,

* From 5576 to 8856 feet. Trans.

either barometrically or trigonometrically, amounts to 208; and they are all distributed over a surface comprehended between the 16° 50' and 21° 0' of north latitude, and the 109° 8' and 98° 28, of west longitude from Paris. Beyond these limits I know but of one place of which the length was accurately ascertained, and that is the city of Durango, elevated, according to a deduction from a mean barometrical altitude, 2000 * metres above the level of the sea. Thus the table-land of Mexico preserves its extraordinary elevation much farther north than the tropic of Cancer. · These measurements of heights, with the astronomical observations which I made on the same extent of ground, have enabled me to construct the physical maps which accompany this work. They contain a series of vertical sections. I have endeavoured to represent whole regions by a method which has hitherto been only employed for mines, or small portions of ground through which canals are intended to pass. In the statistics of the kingdom of New Spain, we must confine ourselves to plans lik-ly to attract interest from views of political economy. The physiognomy of a country, grouping of mountains, extent of plains, elevation which determines its temperature; in short, whatever constitutes the construction of the globe, has the most essential influence on the pro

[ocr errors][merged small]
« ՆախորդըՇարունակել »