The hydrographic basin of the Colorado River commences in the north of Rioja with several rivers which, after forming the Ber mejo, are lost in the lagunes of Huanacache, together with the rivers San Juan and Men doza; and in succession to these we have the streams that run from north to south, which join the waters with the Desaguadero or, as we may call it, the channel for the discharge of the lakes of Huanacache, and this con junction flows on toward the south under the names of Salado, Chadileuvu, and Curico until it falls into the Colorado, having on its course southward formed many lakes and marshes; and lastly the Grande and Barrancas that in combination form the Colorado River, which having traversed the pampas from east to west debouches into the Atlantic Ocean a little to the south of the estuary of Bahia Blanca.
Most of these rivers are used for irrigating the grape and fruit districts of Mendoza and San Juan, as well as the pasture lands of San Luis.
The basin of the Rio Negro is also of great importance, being formed by the streams which flow down from the Cordillera of the Andes between 37° and 41° south latitude. This basin, like all the others that arc found further south, has the peculiarity of encircling within it a large number of lakes which, while con stituting one of the principal attractions of the Cordillera of the Andes, have a beneficial in fluence on the regulation of the waters. There are several other lakes whose natural drainage is the river Limay which, together with the Neuquen, forms the Rio Negro, the mouth of the main river on the Atlantic being a little to the south of the Rio Colorado. The island of Choele-Choel, renowned for its great fertility, is about midway between the confluence of the Limay and Neuquen and the sea, but nearer to the former.
Extensive irrigation works are being com pleted at Negro River, with the purpose of irrigating the barren pampas stretching between that river and the Colorado, as well as the lands south of the Negro. The Patagonian rivers are also navigable to a certain extent. Flat boats have to be used, however.
The drainage of the remaining lakes of the Cordillera is effected by means of the river Senguer, an affluent of the Chubut; the beauti ful lakes of Buenos Aires and San Martin, whose waters make their way through the Cor dillera of the Andes to fall into the Pacific in the same manner as do those of the lake Lacar and many others farther north; the Ar gentino and Viedma lakes whose drainage forms the river Santa Cruz, one of the most important in Patagonia, which, with the Deseado and the Gallegos, completes the hydro graphic system of this region.
The most important rivers of the province of Buenos Aires are the Salado del Sur, whose valley is considered as being only a continuation of that of the Rio Quinto, which flows down from the °Sierras') of •San Luis. This river gives rise to important lagunes and receives, before falling into the bay of San Boromb6n, the superfluity of waters of many others.
The remaining rivers of that province which debouch directly into the ocean are the San Borombon, Quequen Grande, Quequen Salado, Naposta, Sauce Grande and Sauce Chico.
As regards the Argentine Mesopotamia, it is, on account of the impermeability of its soil, a region traversed by numerous rivers and streams which flow into the Parana and Uru guay. The province of Corrientes, in particu lar, contains the immense lagunes of Ibera and Maloya, up to the present almost unexplored.
To conclude this hydrographic sketch of the republic we may call attention to the existence of a certain number of depressions, occupied by salt lakes and deposits of salt, that constitute so many additional basins into which there flow streams of brackish water, which, on evapora tion, deposit the salt they held in solution, forming real natural salt pans, some of them being worked to supply the requirements of the inhabitants of the interior. In the high table lands of Atacama and Jujuy are other deposits which are doubly interesting on account of the deposits of borax which they contain. There are, also, distributed throughout the whole Andine region, numerous water-courses, which are taken advantage of near their sources for the irrigation of the soil but which, their course being through immense zones of permeable land, are quickly lost in the subsoil. Among these we may mention, as examples, the rivers Tala, the Valle, and the Paclin, which give life to the beautiful valley of Catamarca, and to the city of that name. Irrigation works are also prominent in some of these rivers.
Almost any desired climate, from tropical to frigid, may be had in a country that extends through more than 34 degrees of latitude, or more than miles, from latitude to 56° south, and is in places 800 miles wide. Conditions vary widely in the same latitude. Rainfall diminishes from the east to the west until the very base of the Andes is reached. Temperature is highest in the central part of the country, falling rapidly in the Andean region to a point many degrees below the tem perature of localities due east. Temperature also diminishes toward the south.