In 1827, a Belgian, named Adolphe Lisiant, ascended the White Nile to within 150 miles of Khartum. The expedition which he led was aided by an English society, called the "African Association," which became afterwards a part of the Royal Geographical Society. Many explorers visited the White Nile between 1827 and 1845. In 1845, John Pethrick, a Welshman, explored the Nile for coal and precious metals in the interest of Mehemet Ali. After the death of this pasha, Pethrick visited El-Obeid in Kordofan as a trader, and remained there for five years. In 1853 he ventured upon an enterprise relating to the ivory trade. For this purpose he travelled backwards and forwards upon the White Nile and the Bahr-el-Ghazal for a period of six years, reaching some of the important affluents of the Bahr-el-Ghazal, the Jur and the Jalo, or the Rol. Returning to England, he was commissioned to undertake a relief expedition to help Captains Speke and Grant, who had set out upon their journey of exploration, and in the year 1861 he returned to Central Africa. Interest in the slave-trade deterred him from following the directions under which he had been sent out, namely, to bring relief to Speke and Grant. Sir Samuel Baker anticipated him in relieving the expedition, and this so angered Speke that he attempted to have Pethrick deprived of his consular position. Pethrick died in 1882. When Lieutenant Richard Francis Burton had completed his famous journey through Hedjaz to the sacred city of Mecca, he called at the port of Aden at the southwest extremity of Arabia. While there, he made friends with the authorities, and persuaded them to allow him to penetrate Africa through Somaliland, which is situated to the southwest of Abyssinia. He hoped by an overland journey westbound to strike the Nile at its headwaters. John H. Speke accompanied Burton on his journey, and thus gained his first experience of African exploration. Unfortunately this expedition was not a success, for the Somali were so suspicious of the object of the travellers that they forced them to return to the coast. [Illustraton: 277.jpg THE MAIN STREAM OF THE NILE]