On his arrival in London in September 1804, Park presented a written statement to the Colonial Office embodying his views as to the commercial and geographical results likely to accrue from the intended expedition, at the same time pointing out the best means to accomplish the work as regards men and goods. In this memorandum he pointed out the course he proposed to pursue. Passing through Bondu, Kajaaga, Fuladu, and Bambarra to Sego, he would construct a boat and proceed by way of Jenné and Kabara (the port of Timbuktu) through the kingdoms of Haussa, Nyffé (now called Nupé), and Kashna, &c., to the kingdom of Wangara. If the river ended here, he pointed out, his chief difficulty would begin. To return by the Niger, to cross the desert to Tripoli or Egypt, or to pass eastward to the Nile and Abyssinia, he considered equally difficult. The most feasible course seemed that towards the Bight of Benin. If, however, the Niger was, as he confidently believed, in reality the Congo, he would follow it to its termination. After pointing out the grounds for his belief, Park concluded with the opinion that when “your Lordship shall have duly weighed the above reasons, you will be induced to conclude that my hopes of returning by the Congo are not altogether fanciful, and that the expedition, though attended with extreme danger, promises to be productive of the utmost advantage to Great Britain. Considered in a commercial point of view, it is second only to the discovery of the Cape of Good Hope, and in a geographical point of view is certainly the greatest discovery that remains to be made in the world”--a very strong statement of the case, it must be admitted, though undoubtedly if the Niger and the Congo had proved to be one, it could scarcely have been said to be too strong.
Park had been converted to this view of the identity of the two great rivers by one George Maxwell, a West African trader, who had seen much of the Congo near its mouth, and had published a chart embodying the results of his observations. When closely examined, the arguments in its favour were of small value, and practically arose out of the fact that there was a large river with a southerly trend whose termination was unknown, while further south there was a second, the Congo, whose origin was equally a mystery. Prolong these in the necessary direction and the result is identity, and the mystery of both is settled.