Burton got permission to try to reach the centre of Africa through Somaliland, with T. H. Speke. Burton first made a courageous and successful journey to the walled city of Harar in Abyssinia; but the more important stage of the expedition was unsuccessful owing to the suspicions of the Somalis. For thirty years after this Somaliland remained unexplored, and Burton and Speke, inspired by the accounts of the Zanzibar missionaries, devoted themselves to the discovery of the source of the Nile. They arrived at Zanzibar in 1856, and penetrated without much difficulty to the great plateau of Unyamwezi, where the Arab traders received them kindly, and thence to Lake Tanganyika. Burton was forced through illness to allow Speke to continue the work without him, and the latter saw, though from a distance, the waters of the Victoria Nyanza. Though he underestimated its size, he was convinced that here was the answer to the question of the Nile source; but Burton, jealous of his success, refused to credit it, and endeavoured to prove that the Victoria Nyanza was nothing but a great swamp. In 1860, however, Speke set out again, with J. A. Grant, and verified and enlarged his previous discoveries. In face of immense difficulties due to mutinous porters and suspicious and warlike chiefs, he succeeded in making a rapid survey of the Victoria Nyanza, in exploring the unknown country of Uganda, and in finding the Ripon Falls, where the Victoria Nile leaves the lake. In spite of the great gaps in Speke’s knowledge, his ideas on the relative importance of the Nile tributaries and of the geography of the lakes were very accurate, and the honour of settling the old question of its source must be given to him. Speke and Grant were met on their return at Gondokoro on the Nile by Samuel Baker, who had come with help and reinforcements for them, and he took up the work of definitely locating the Albert Nyanza, of which Speke had heard various accounts. Though he and his wife passed through terrible dangers and difficulties, they completed their task, finding the Albert Nyanza, and journeying along the Victoria Nile as far as the Murchison Falls. The importance of Baker’s discovery, however, was somewhat vitiated by his erroneous judgment of the size of the Albert Nyanza, which he made far too large; he, like the other explorers who had gone before him, saw nothing of the great snow-range.