=Rivers.= The only rivers of consequence are those which flow towards the Atlantic, with the exception of the Desaguadero, about 200 miles long, the outlet of Lake Titicaca. This river flows into Lake Pampa Aullagas or Poopo, which has no outlet unless it be by an underground stream to the Pacific, of which there are some indications. The principal rivers of the Plata system, the Pilcomayo and the Bermejo, flow southeast into the Paraguay River. More numerous and important are the streams flowing northeast belonging to the Amazon Basin, the chief of these, the Beni, and the Mamoré, which form the Madera River. They have many tributaries, the Beni having the Madre de Dios, the Madidi, the Cochabamba, and others; the Mamoré receiving the great boundary river, the Guaporé or Itenez, and many more. CLIMATE Bolivia, still within the tropics, has the same variety of climate as the countries previously described, the difference in altitude causing the variation. The portion of the table-land where the altitude is 12,000 to 13,000 feet, called the _puna_ by the natives, has two seasons which resemble autumn and winter, the summer is so short and cool. The summer, the season of snows, is from October or November to May; the winter usually has slight precipitation. Little will grow here except potatoes, barley, and _quinua_. The higher land up to the snow line, perhaps 17,000 feet, called the _puna brava_, is still colder, supporting grass only, where herders alone are found with native flocks and rare mining settlements. Higher still is eternal snow with almost Arctic temperature, -20° I found it at night on a glacier on Mt. Sorata. A professor once told me that at 16,000 feet he was unable to keep warm at night however much clothing and blankets he used, but the Indians, moderately clad and with bare feet, endure the cold with apparent indifference.