John Hanning Speke although the pair seemed to have shared the hardships and labors of the journey pretty much evenly. Once it became clear that Speke might have found the source of the Nile the relationship deteriorated further. Why Burton did not journey back to Lake Victoria with Speke to make a better reconnoitre of the Lake after Speke returned to base camp in Kazeh is unclear. Burton was incapacitated and had to be carried by bearers but this had been true for a great deal of the trip. While Speke and Burton were instrumental in bringing the source of the Nile to
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