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
Bob Rafelson "Black Widow" are the joys of a film well made--the cinematography of Conrad Hall, the production design of Gene Callahan, and a fabulous cast," which also featured Dennis Hopper, Nicol Williamson, and Diane Ladd. In 1990 Rafelson directed "Mountains of the Moon", a film about the 1857–58 journey of Richard Francis Burton and John Hanning Speke in their expedition to central Africa — the project that culminated in Speke's discovery of the source of the Nile River. It starred Patrick Bergin as Burton and Iain Glen as Speke, and was hailed by critic Roger Ebert as "completely absorbing." Ebert continued,