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 he found hard and time consuming as he was not naturally a gifted writer. He failed to give a good and full report to the RGS for many months and thus in effect was not defending his positions of discovery. In addition Speke had a public dispute with the Pethericks who had by and large acted according to their RGS instructions but Speke had felt they had not. All this led Roderick Murchison, president of the Royal Geographical Society, to start disliking Speke and a third expedition, led by Speke, was becoming less likely as it would have to be