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
John Hanning Speke Speke was much attached to Bombay and spoke highly of his honesty and conscientiousness. Bombay's efforts in dealing with hostile tribes, interpreting and keeping the safari crew on track was a great help to the expedition. Less is known of Mabruki, the other caravan leader, but he was later known as Mabruki Speke, and like Bombay became one of East Africa's great caravan leaders and was also a member of the Yao tribe like Bombay. Because of Speke's recommendations both Bombay and Mabruki served on Henry Stanley's 1871 expedition to find Livingstone. On 26 September 1859 the return journey from