To the north of the Rio Salado, at the portals of the Andes, the country assumes a look of implacable desolation; no winds ever agitate the lower strata of the atmosphere. The water-courses which descend from the mountains lose themselves in the sand; salt marshes, whence the very birds hold aloof, alone alternate with a soil everywhere intersected by crevices. The district of the Pampas which stretches northward to the spurs of the Andes consists of a sandy soil, free from salt, but wholly unproductive. These solitudes, however, are ploughed by running streams, none of which communicate with the sea. They descend from the Andes, traverse the Pampas from east to west, and empty themselves into the saline lakes. Somewhat further to the north, and nearer the Equator, lies an almost unknown region of salt--a region of indescribable gloom, where neither tree, nor bush, nor blade of emerald grass, delights the eye. Eighteen months frequently elapse in this land of desolation, worthy of being one of the circles in Dante's "Inferno," without the cheering sound of a shower of rain, and when at length it arrives, it splits the rocks of salt and melts them into wide pools of brackish mud. As soon as the sun has absorbed the excessive humidity of the soil, myriads of salt crystals glitter on the surface, and convert the Desert into one immense mirror. To the north-west of La Plata extends a desert of very different character--the _Despoblado_, or uninhabited land, a plateau of the Andes, rising some 4200 feet above the level of the sea. This desert is cloven into two portions by a deep valley, bordered with sharp rocks, which affords the only practicable route from Bolivia to Buenos Ayres. Winter, in this sombre world within a world, is a time of horror, when the spirit of Desolation goes to and fro in wrath unchained. Yet even here humanity drags about the fetters of existence. The traveller occasionally alights upon the wretched huts where the unfortunate descendants of the ancient Peruvians linger through life. Their wealth consists in a few llamas. Their occupation, in hunting the alpaca, the guanaco, and the chinchilla; in filtering the river sands for scanty grains of gold; in collecting salt, and disposing of it to the inhabitants of the nearest towns.