About the distance of 500 miles from Buenos Ayres, the country is one plain, covered only with cattle, horses and mules, and stretching to the horizon; the land then begins insensibly to rise, and in 500 miles more, the road lies over the branches of the chain of Chiquitos, to the town of Salta, where the grand and snow-covered tops of the central Andes present themselves. The thick woods of Tucuman are then lost; but the swarms of locusts, crickets, ants, mosquitoes, toads, frogs, serpents, and alligators, also disappear, the traveller having now entered the temperate region; the road then winds amid abrupt and frightful precipices and chasms, and sometimes with so narrow a footway that the mules can scarcely move. The path is here indented with deep holes, in which the animals place their legs, and thus prevent the danger of slipping over the precipices; at other places where the road inclines at a great slope, these sagacious creatures place themselves with their fore and hind feet close together, and inclining forward, as if about to lie down, they slide with inconceivable velocity to the bottom. These mountains in some parts are traversed at the bottom of narrow and perpendicular clefts, where, if the animal falls, his rider must infallibly be crushed. The passage of the many torrents and rivers is also another difficulty; across those which are shallow, very large and high horses are used, which are trained for the purpose; over the deeper ones, rope bridges are thrown; and it is only in summer that this journey can be attempted, as the swelling of the rivers and the winter torrents render them impracticable. Even in summer, when the snow in the higher regions suddenly melts, the torrents are swoln to such a degree, and dash with such force from the mountains, that many an unhappy traveller perishes. Mules constitute the great commerce of Tucuman; these animals are bought in Cordova, Santa Fé and Buenos Ayres, and being fattened during the winter in the valleys and plains, are driven to Peru, where they sell for twelve or seventeen dollars each, 50,000 being thus sold every year, and with them are driven from 14 to 16,000 cows. It also sends soap wrapped in hides to Peru; but the importation of all articles is subject to a toll, on passing the Peruvian frontier, the produce of which is applied to the pay of the troops, the repair of the forts, and the defence of the frontier against the unsubdued Indians; for there is not a government in all America so liable to the incursions of these tribes as Tucuman, as they surround it on the east and south; for which reason its population has not much increased, the settlers being continually liable to lose their property from these irruptions. Of the forts built for the protection of the government, there are at present thirteen; and the amount of the population, including the converted Indians, is 100,000.