John Hanning Speke questions about the height and extent of the lake could not be answered easily. Speke's eyes were still bothering him and he only saw a small part of the southern end of the lake and his view was blocked by islands in the lake so he could not judge the size of the lake well. However, Speke did estimate the elevation of Lake Victoria at 4000 feet by observing the temperature at which water boiled at that level. (This lake's being substantially higher than Lake Tanganyika did make it a more likely candidate for the source of the Nile.) From
Ruzizi River longest bridge, crosses the river near its mouth. Tributaries of the Ruzizi River include the Nyamagana, Muhira, Kaburantwa, Kagunuzi, Rubyiro and Ruhwa, among others. The Ruzizi River, flowing south into Lake Tanganyika, is part of the upper watershed of the Congo River. Nineteenth-century British explorers such as Richard Francis Burton and John Hanning Speke, uncertain of the direction of flow of the Ruzizi, thought that it might flow north out of the lake toward the White Nile. Their research and follow-up explorations by David Livingstone and Henry Morton Stanley established among Europeans that this was not the case. The Ruzizi