John Hanning Speke But Burton was too weak to make the trip and thus stayed in base camp when the main caravan halted again at Kazeh. Speke went on a 47-day side trip that was 452 miles up and down in which he took 34 men with Bombay and Mabruki as his captains and on 30 July 1858 became the first European to see Lake Victoria and the first to map it. It was this lake that eventually proved to be the source of the River Nile. However, much of the expedition's survey equipment had been lost at this point and thus vital
John Hanning Speke tried to remove it with a knife. Unable to rent the larger vessel from the Arab, Speke returned. The pair were unable to explore Lake Tanganyika properly and they initially misunderstood that a river flowed out of it from the north side. A few weeks later Sidi Mubarak Bombay confirmed via locals that the river flowed into the lake; however, since neither man actually saw this river, this remained a source of speculation. They had also heard of a second lake to the north-east, and in May 1858, they decided to explore it on the way back to the coast.