Burton became gravely ill and Speke went temporarily blind as they travelled further west. After an arduous journey, the two arrived in Ujiji in February 1858 and became the first Europeans to reach Lake Tanganyika (although Speke was partially blind at this point and could not properly see the lake). They decided to explore the lake, but it was vast and they could get only small canoes from the locals. Burton was too ill to journey, and thus Speke crossed the lake with a small crew and some canoes to try to rent a larger vessel from an Arab who, they were told, had a large boat and lived on the west side of the lake. (Lake Tanganyika is over 400 miles long on the north–south axis but only about 30 miles wide.) During this trip Speke, marooned on an island, suffered severely when he became temporarily deaf after a beetle crawled into his ear and he 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 the explorer and guide 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. Speke's travels to Lake Victoria 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. 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, known to locals as Nam Lolwe in the Dholuo language and Nnalubaale or Ukerewe in the Luganda language. Speke renamed the lake after the British monarch, Queen Victoria, and was one of the first persons 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 questions about