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 equal to that of France and Spain. The waters find their way to the falls of the Madeira by many great rivers, the principal of which, if we enumerate them from east to west, are the Guaporé or Itenez, the Baures and Blanco, the Itonama or San Miguel, the Mamoré, Beni, and Mayutata or Madre de Dios, all of which are reinforced by numerous secondary but powerful affluents. The Guaporé presents many difficulties to continuous navigation; the Baures and Itonama offer hundreds of miles of navigable waters through beautiful plains; the Mamoré has been sounded by the writer in the driest month of the year for a distance of 500 m. above Guajará-Merim, who found never less than from 10 to 30 ft. of water, with a current of from 1 to 3 m. an hour. Its Rio Grande branch, explored under the writer’s instructions, was found navigable for craft drawing 3 ft. of water to within 30 m. of Santa Cruz de la Sierra—a level sandy plain intervening. The Grande is a river of enormous length, rising in a great valley of the Andes between the important cities of Sucre and Cochabamba, and having its upper waters in close touch with those of the Pilcomayo branch of the river Paraguay. It makes a long curve through the mountains, and, after a course of about 800 m., joins the Mamoré near 15° S. lat. The Chaparé, Securé and Chimoré, tributaries of the Mamoré, are navigable for launches up to the base of the mountains, to within 130 m. of Cochabamba. The Beni has a 12-ft. fall 18 m. above its mouth called “La Esperanza”; beyond this, it is navigable for 217 m. to the port of Reyes for launches in the dry season and larger craft in the wet one. The extreme source of the Beni is the little river La Paz, which rises in the inter-Andean region, a few miles south-east of Lake Titicaca, and flows as a rivulet through the Bolivian city of La Paz. From this point to Reyes the river is a torrent. The principal affluent of the Beni, and one which exceeds it in volume, enters it 120 m. above its mouth, and is known to the Indians along its banks as the Mayutata, but the Peruvians call it the Madre de Dios. Its ramifications drain the slopes of the Andes between 12° and 15° of latitude. It is navigable in the wet season to within 180 m, of Cuzco. Its upper waters are separated by only a short transitable canoe portage of 7 m. in a straight line from those of the Ucayali. The portage on the eastern side terminates at the Cashpajali river 22 m. above its junction with the Manu. For the first 13 m. it is navigable all the year for craft drawing 18 in. of water, but the remaining 9 m. present many obstacles to navigation. At the Manu junction the elevation above sea-level is 1070 ft., the river width 300 ft., depth 8 ft., current 1 m. per hour. The general direction of the Manu is south-east for 158 m. as far as the Pilcopata river, where under the name of Madre de Dios it continues with a flow of 22,000 cubic metres per minute. Here its elevation is 718 ft. above the sea and its width 500 ft. During the above course of 158 m. the Manu receives 135 large and small affluents. Although the inclination of its bed is not great, the obstacles to free navigation are abundant, and consist of enormous trees and masses of tree-trunks which have filled the river during the period of freshets.

From the time it receives the Manu, the Madre de Dios carries its immense volume of waters 485 m. to the Beni over the extremely easy slope of a vast and fertile plain. Its banks are low, its bottom pebbly. A greater part of its course is filled with large and small islands some 63 in number. Its average width is about 1500 ft. Below the mouth of the Tambopata, the flow is estimated at 191,250 cubic metres per minute. The average current is 2 m. per hour. There are two important rapids and one cataract on the lower 300 m. of the river.

The Mayutata receives three principal tributaries from the south—the Tambopata, Inambari and Pilcopata.

The Peruvian government has sought to open a trade route between the Rio Ucayali and the rich rubber districts of the