Narrative of Travels and Discoveries in Northern and Central Africa, in the Years 1822, 1823, and 1824, by Major Denham, Captain Clapperton, and the Late Doctor Oudney, Extending Across the Great Desert to the Tenth Degree of Northern Latitude, and from Kouka in Bornou, to Sackatoo, the Capital of the Fellatah Empire. With an Appendix ... by Major Dixon Denham, of His Majesty's 17th Regiment of Foot, and Captain Hugh Clapperton, of the Royal Navy, the Survivors of the Expedition