<Dl> <Dd> Petherick was a well known Welsh traveler in East Central Africa where he had adopted the profession of mining engineer . This work describes sixteen years of his travel throughout Africa . In 1845, he entered the service of Mehemet Ali, and was employed in examining Upper Egypt, Nubia, the Red Sea coast and Kordofan in an unsuccessful search for coal . In 1848, he left the Egyptian service and established himself at El Obeid as a trader and was, at the same time made British Consul for the Sudan . In 1853, he removed to Khartoum and became an ivory trader . He traveled extensively in the Bahr - el - Ghazal region, then almost unknown, exploring the Jur, Yalo and other affluents of the Ghazal and in 1858 he penetrated the Niam - Niam country . Petherick's additions to the knowledge of natural history were considerable, being responsible for the discovery of a number of new species . In 1859, he returned to England where he became acquainted with John Speke, then arranging for an expedition to discover the source of the Nile . While in England, Petherick married and published this account of his travels . He got the idea to join Speke in his travels, and in this volume is an actual subscription and list of subscribers to raise money to send Petherick to join Speke . His subsequent adventures as a consul in Africa were published in a later work . </Dd> </Dl> <Dd> Petherick was a well known Welsh traveler in East Central Africa where he had adopted the profession of mining engineer . This work describes sixteen years of his travel throughout Africa . In 1845, he entered the service of Mehemet Ali, and was employed in examining Upper Egypt, Nubia, the Red Sea coast and Kordofan in an unsuccessful search for coal . In 1848, he left the Egyptian service and established himself at El Obeid as a trader and was, at the same time made British Consul for the Sudan . In 1853, he removed to Khartoum and became an ivory trader . He traveled extensively in the Bahr - el - Ghazal region, then almost unknown, exploring the Jur, Yalo and other affluents of the Ghazal and in 1858 he penetrated the Niam - Niam country . Petherick's additions to the knowledge of natural history were considerable, being responsible for the discovery of a number of new species . In 1859, he returned to England where he became acquainted with John Speke, then arranging for an expedition to discover the source of the Nile . While in England, Petherick married and published this account of his travels . He got the idea to join Speke in his travels, and in this volume is an actual subscription and list of subscribers to raise money to send Petherick to join Speke . His subsequent adventures as a consul in Africa were published in a later work . </Dd> <Ul> <Li> Journal of the Discovery of the Source of the Nile, John Hanning Speke . William Blackwood, Edinburgh, 1863; Harper & Brothers, New York; 1864 </Li> </Ul> <Li> Journal of the Discovery of the Source of the Nile, John Hanning Speke . William Blackwood, Edinburgh, 1863; Harper & Brothers, New York; 1864 </Li>

Which of the following is the northernmost city located on the nile river