Journal of the discovery of the source of the Nile.

The account of Speke's third and final expedition to Africa. This took place in 1860 with his friend and fellow Indian army officer James Grant (1827-1892) on an expedition organized by the Royal Geographic Society and supported by the British government. Their purpose was to explore the Victoria Nyanza area and confirm Speke's earlier view that the lake was the source of the White Nile.

Back in England, Speke was showered with honours and feted by the Royal Geographical Society. But doubts of his claim remained, voiced particularly by Burton, primarily because Speke had not followed the Nile from Karuma Falls to Gondokoro. (Using Speke's maps, Baker would discover what Speke had thereby missed Lake Albert.) A debate with his former friend-turned-nemesis Burton was arranged for 16 September 1864 to settle the matter; however, on that morning word arrived that Speke had died in a gun accident. Some thought it was suicide, for he was known as an accomplished sportsman and hunter. Speke and Grant's successes are undisputed, however they were the first Europeans to cross equatorial eastern Africa, and their explorations added more than 500 miles to the known geography of the area. Today Lake Victoria and its feeder streams are considered the sources of the White Nile.