The communications in question, operating on the minds of intelligent Members of the African Society, and giving a spur to the curiosity and enterprize of the agents they might employ, formed a suitable and necessary PREFACE to the undertaking and efforts for practical discovery, and for ensuring the advantages thence to be derived. The compilation of various informations respecting Africa, had thus an intrinsic value, as affording premises of inquiry, and as giving encouragement and direction to adventure. But further, and even immediately, wisdom and sagacity will extract truth from accounts, however contradictory, and useful and certain inference, from documents the most ambiguous or incomplete. Efforts of rude ingenuity often suggest not only improvement but discovery; the rustic forms a lever to raise the mass, and the sagacity of the mechanic applies it to ascertain the weight. Science often works with effect on the loose and disjointed materials which ignorance has heaped together; compares, arranges, and connects their substances and forms; shews in their matter, construction, or decomposition, new uses; derives new informations, and adds to the stock of human inventions and knowledge. Were it necessary to illustrate such position by example, the writer would refer, as a special instance, to the elucidations of Major Rennell on the communications in question: to that most accurate and acute philosopher and geographer, the details have afforded matter of enquiry and deduction of the highest import to science. By analysis, and a comparative view of accounts given of journies and places, in reference to the plans of D’Anville, and other geographers; to modern travels; to ancient expeditions; to descriptions of ancient writers; and above all, to those of the father of history, Herodotus; Major Rennell hath corrected the map of Africa, with a learning and sagacity which _hath converted conjecture into knowledge_; and on experience of those who have explored parts of that great continent, given confidence to each future traveller who may visit its remotest regions. Had the proceedings of the Society stopped here, and its work been confined to the compilation above alluded to, and to the comments of Major Rennell, the usefulness of its institution would have been acknowledged by posterity. But happily the Journal of Mr. Park’s travels to the Niger, and that of Mr. Horneman’s journey from Cairo to Mourzouk, will fully shew, that the attainments of the Society are no longer narrowed to the mere rudiments of discovery, which tradition and ingenious inference, alone before supplied.