Henry Morton Stanley the source of the Nile. Between 1875 and 1876 Stanley succeeded in the first part of his objective, establishing that Lake Victoria had only a single outlet – the one located by John Hanning Speke on 21 July 1862. If this was not the Nile's source, then the massive northward flowing river called by Livingstone, the Lualaba, and mapped by him in its upper reaches, might flow on north to connect with the Nile via Lake Albert and thus be the primary source. It was therefore essential that Stanley should trace the course of the Lualaba downstream (northward) from Nyangwe,
Hamites races were too broad to have stemmed from a single common ancestor, but were instead consistent with separate racial origins. In his "Crania Aegyptiaca" (1844), Morton analyzed over a hundred intact crania gathered from the Nile Valley, and concluded that the ancient Egyptians were racially akin to Europeans. His conclusions would establish the foundation for the American School of anthropology, and would also influence proponents of polygenism. In the second half of the 19th century, the British explorer John Hanning Speke would further popularize the ancient Hamitic peregrinations in his publications on his search for the source of the Nile