Between 1856 and 1865 Paul du Chaillu trav eled extensively on the west coast, in the neigh borhood of the river Ogowe (or Ogobai). In 1861-62 Maj. (afterward Sir) R. F. Burton also traveled on the west coast. He ascended the Kamerun Mountains and confirmed some of the observations of Du Chaillu. A French ex pedition visited the delta of the Ogowe in 1864. After that the river basin was very fully explored, the principal expeditions being those of Walker, 1866, 1873; Lieutenant Aymes, 1867-68; the Frenchmen Compiegne and Marche, 1872-74; Dr. 0. Lenz, 1876; and another French expedition under Savorgnan de Brazza, 1876, who took possession of a large stretch of terri tory for France. This territory now forms part of French Kongo, which had been tra versed by various Frenchmen, including Brazza, Mizon, Le Maistre, Monteil and others.
In 1866 Livingstone entered on his last great series of explorations, the main object of which was to settle the position of the watersheds in the interior of the continent south of the equator, and to discover the source of the Nile. Landing at the mouth of the Rovuma he pro ceeded southwest round the south end of Lake Nyassa, and then traveling north reached the south end of Lake Tanganyika (discovered by Speke and Burton in 1858). He afterward vis ited Lakes Mweru and Bangweolo in the basin of the Chambeze, the name given to a headwater of the Kongo. In 1869 he reached Ujiji, on the Tanganyika, and crossed the lake, making ex tensive journeys in the Manyuema country, and reached the Lualaba or upper Kongo, but could not explore it for want of boats. Henry M. Stanley, who had been specially sent by the proprietor of the New York Herald to search for Livingstone, met him at Ujiji on his return from the Manyuema country, relieved his neces sities and examined along with him the northern end of Lake Tanganyika. Livingstone after ward started on a fresh journey (in 1872) to determine the course of the Lualaba, intending to travel round the south side of Lake Bang weolo; but after suffering much from illness he died on the shore of this lake on 1 May 1873.
In 1872 the Royal Geographical Society or ganized two expeditions too in search of Liv ingstone. The one, under Grandy, sailed some distance up the Kongo ; the other, under Lieutenant Cameron, started from Zan zibar for Tanganyika. On ascertaining the death of Livingstone he proceeded to Lake Tanganyika, where he secured Livingstone's map and sent it to Zanzibar. He ascertained the height of the lake; found an outlet, the Lukuga, on the west side; traversed the Man yuema country; reached Nyangwe, Living stone's farthest point on the Luabala; pro ceeded south up the east side of the valley of Lomane to Kilemba in the Urua country; and reached Benguela, on the Atlantic coast, 4 Nov.
187$. The identity of the Kongo and Lualaba was at last settled by Stanley, who, between October 1876 and August 1877, descended from Nyangwe on the latter river to the mouth of the former. After helping to establish the Kongo Free State (1879-85) Stanley pro ceeded in 1887 with an expedition to relieve Emin Pasha, Gordon's lieutenant, who, after the fall of Khartum, had retreated into the interior. Following the Kongo and its tribu tary the Aruwini, Stanley hewed his way through a vast forest, arrived at the Albert Nyanza, met Emin there, returned for his rear guard and stores, and at last brought Emin and his followers to Bagamoyo, on the east coast, in 1889. He also discovered Lake Albert Ed ward and the lofty mountain of Ruwenzori, on the Semliki, between that lake and Lake Albert. The Portuguese Major Serpa Pinto journeyed from Benguela to Natal in 1878-79; the Germans Wissmann and Pogge crossed from St. Paul de Loanda to Zanzibar in 1::1 82; in 1879-80 (after the death of his leader, Keith Johnston), Joseph Thomson crossed from the east coast by the north of Lake Nyassa to the east of Tanganyika and back to Zanzibar; again in 1883-M he explored the Masai country between the coast and Lake Victoria; Capello and Ivens went from Angola to Mozambique by way of Bangweolo in 1884-85.
One of the most interesting problems con nected with African geography was the trac• ing of the source of the Nile. Among the first of the famous explorers in this direction was James Bruce, who, in 1770, reached the source of the Blue Nile or Bahr-el-Azrek and imagined himself to have solved the great problem. But the real source of the Nile re mained long unknown, the great lakes con nected with its origin being hardly dreamed of till comparatively recent times. In 1858 Bur ton and Speke, crossing from Zanzibar, dis covered Lake Tanganyika, and the same year Speke also reached the Victoria Nyanza, but did not ascertain that it gave rise to the Nile. Speke and Grant in 1862 reached the place where the Nile leaves the lake and followed part of its course to Karuma Falls. At Gon dokoro they met Sir Samuel Baker, who pro ceeded to investigate the unexplored part, but did not fully succeed in his object. Baker in 1871-73 returned to the scene of his explora tions as the commander of an Egyptian force and took possession of the country in the name of the Khedive, but added little to his previous geographical discoveries. He was succeeded in his command by Colonel Gordon, one of whose officers, Colonel Long, more fully traced the Nile between Karuma Falls and the Vic toria Lake; while another, M. Gessi, first ac tually traced the Nile up to its outflow from the Albert Nyanza (1876).