but not until 1830 was knowledge of the river completed by the brothers Lander. Its sources were discovered in 1897 by Moustier and Zweifel. In 1830 the French began the conquest of Algeria, and began to colonize it, especially since the Franco-Prussian War, and they have gradually pushed its boundary S. into the Sahara. In 1850-1855, Barth, who was followed by many other travelers, explored the Sudan, especially the neighborhood of Lake Tchad, and reached Timbuktu. Napoleon's expedition had given a great impulse to scientific exploration, which was encouraged later by the khedives and led to the conquest of Nubia and Sennar by Mehemet Ali (1805-1848), and, with the additional object of suppressing the slave trade, to the annexation of the east Sudan by Ismail Pasha (1863-1879). The Nile has been an object of active interest since 1810, when Salt reached its Abyssinian branches. In 1840-1841, Mehemet Ali sent two expeditions to discover the sources of the main river, and, in 1860, Miani reached as far as 3° 34' N. latitude. Further exploration was from the S. The existence of great lakes in central Africa had been known at Mozambique from an early date, and, attention being called to this fact, led to the discovery, in 1849, of the extinct volcanoes, Kilimanjaro and Kenia, by Rebmann and Krapf respectively.
In 1856 Du Chaillu explored the southern Ogowe, and, in 1864, penetrated into Ashango and discovered the dwarfs of Obongo. In 1858 Burton discovered Lake Tanganyika. In 1858 Lake Victoria Nyanza, then called Ukerewe, was discovered by Speke, who, in 1862, was able to prove that its overflow constituted the origin of the Nile. In 1864 Sir Samuel Baker discovered Lake Albert Nyanza, and later Stanley discovered Lake Albert Edward Nyanza. In 1849-1856 Livingstone discovered Lake Ngami, crossed the Kalahari desert, and returned across Africa from St. Paul de Loanda to the mouth of the Zambezi, being the first to accomplish this feat. In 1859 he discovered the Nyassa and Chilwa lakes. In 1858-1864 he explored the Zambezi and its tributaries; in 1867-1868 he discovered Lakes Mweru and Bangweolo; and, from 1868 to his death in 1873, he investigated Lake Tanganyika and the headwaters of the Kongo. In 1871 he was found by Stanley at Ujiji. The desire to solve the problem of the Kongo basin led to many expeditions, but the final solution was obtained by Stanley in his journey across the continent in 1874-1877; he showed that the origin of the Kongo was to be found in the Lualaba and the Luapula or Chambeze. The latter, he proved, passes through Lake Bangweolo and joins it with Lake Mweru. He also succeeded in strictly defining the sources of the Nile. In 1884-1885 Grenfell proved the identity of the Ubanggi, the principal tributary of the Kongo, with the Makua or Welle, names previously given to its upper course.
Later Discoveries.—In 1893 and 1894 Marchand explored the regions of Great Bassam on the Ivory Coast, directly N. to the junction of the Bagoe and the Niger. In 1890 Marinel, and, in 1891, Bia, reached the S. E. sources of the Kongo in Kantaga. In 1893 Mohun proved the non-existence of Lake Landji. In 1891 and 1894 De la Khetulle explored from Ubangi to Dar Nefertit. In 1891 Crampel and Dybowski were the first Europeans to cross the Kongo Shari watershed. In 1892 and 1893 Maistre succeeded in penetrating from Ubangi to Logoni and Binuë. In 1891 Fourneau, in 1891-1894 Brazza, and in 1895 Clozel, explored the Sanga Mambere, an affluent of the lower Kongo. A number of explorers also have penetrated the equatorial W. coast: Bottego and Grixioni, 1892 and 1893; Prince Ruspoli, 1893 and 1894; Count Hoyos, 1893 and 1894. Donaldson Smith in 1894 and 1895 explored the interior of Somaliland. The highlands between Tana, Sabaki, and Kenia were explored by Pigott, Hohnel, and Chanler. Baumann, Stuhlmann, and Verther crossed the Massai steppe. The expedition of Shele in 1894, of Marenski in 1892, and Bumiller, also gave important information regarding the southern half of the German boundary.
In the first years of the 20th century great progress was made in scientific exploration in Africa. Previous to that time indeed, Marchand traversed the continent from Loanga in French Kongo to Fashoda on the Nile. The Lake Tchad region and the Sahara desert were traversed at the same time by other French explorers. Between 1900 and 1904 Pierre crossed the continent following in General Marchand's route. In 1909 Gautier crossed the Sahara desert from Tuat to the Niger river. German explorers also were active at this period. Dr. Stuhlmann made a study of the region of Victoria Nyanza and Dr. Hans Meyer made the first ascent of Mount Kilimanjaro.
By this time the era of exploration began to be superseded by one of detailed study of the geography of Africa, the ethnology of its people and the variety and quantity of its resources. This work advanced so rapidly that by 1913 the
