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
Sidi Mubarak Bombay slave in India many years and learned Hindi. He was emancipated after his owner died, and returned to Africa. In Africa, Bombay met John Hanning Speke, who asked him to join his expedition to find the source of the Nile River. Bombay and Speke communicated with each other in Hindi, as it was the only language both of them understood. Bombay was well regarded by the British explorers; in the words of Burton, "The gem of the party, however, is one Sidi Mubarak, who has taken to himself the agnomen of 'Bombay.'" Between 1856 and 1876, Bombay participated in expeditions