TRAVELS OF RICHARD AND JOHN LANDER, INTO THE INTERIOR OF AFRICA, FOR THE DISCOVERY OF THE COURSE AND TERMINATION OF THE NIGER; FROM UNPUBLISHED DOCUMENTS IN THE POSSESSION OF THE LATE CAPT. JOHN WILLIAM BARBER FULLERTON, Employed in the African Service: WITH _A Prefatory Analysis of the Previous Travels_ OF PARK, DENHAM, CLAPPERTON, ADAMS, LYON,