John Hanning Speke arrange a better relationship for Mere with another man, without success it seems. Finally, given permission by Mutesa in June 1862 to leave, Speke then travelled down the Nile now reunited with Grant. Because of travel restrictions placed by the local chieftains, slave raiding parties, tribal wars and the difficulty of the terrain, Speke was not able to map the entire flow of the Nile from Lake Victoria north. Why he did not make more efforts to do so is not clear, but the enormous hardships of the journey must have played a large role. By January 1863 Speke and
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.