Their inquiries, however, were not to be bounded by the Sahara any more than the first onrush of the Mohammedan torrent. The routes of the large caravans to the Sudan were made a subject of investigation, and the Arab writers laid under contribution to satisfy the demand for more light. To the Niger especially their inquiries were turned, in the hope of solving the mystery of its true position and its course. Where did it commence and where did it end? was the double problem which puzzled the eighteenth century geographers more even than the question of the source of the Nile. Not content with inquiries which only landed them in perplexities and endless discussion, they resolved to send out explorers. To such they offered no monetary inducements, no hope of tangible reward. The honour and glory of discovery were to be their prize: the Association at the same time undertaking, for their part, to defray the traveller’s expenses. The inducements offered were quite sufficient. Admirably qualified men presented themselves in greater numbers than were needed, so that the chief difficulty of the Association was to choose rather than to seek. The first of the heroic band of African pioneers was Ledyard, already a traveller of the most varied experience. His mission was to cross the African Continent from the Nile to the Atlantic. At the threshold of his enterprise he perished of fever in 1788. Mr. Lucas was the next to take up the work. His qualifications were an intimate knowledge of Moorish life and language, gathered first as a slave in Morocco, then as British Vice-Consul to that empire. The work marked out for him was to start from Tripoli and cross the Sahara to the Sudan. In this he failed. A revolt of Arab tribes barred the way, and Mr. Lucas abandoned the enterprise, bringing back with him only additional particulars regarding the interior, which he had gathered from native merchants. More successful in the earlier part of a succeeding expedition was Horneman (1789), who undoubtedly crossed the desert, but crossed it only to disappear for ever. Clearly Africa was a hard nut to crack, and dangerous to whomsoever should essay it. Foiled in their attempts to reach the goal of their desires from the north, the African Association next turned to West Africa for a possible opening to the interior. Once more the Gambia was chosen as the most direct and feasible route. In Major Houghton they seemed to have got the right man for the work. As Consul at Morocco he had gained an acquaintance with the Moors and their language, and at Goree, then in British hands, he had come in contact with the West African negro, and learned the conditions of life and travel obtaining in the Gambia region.