The Nuttall Encyclopedia
German traveller and explorer; visited (1869-1874), the first European to do so, at the instance of Prussia, by way of Tripoli, the heart of Africa, and returned by way of Cairo, and wrote an account of his journey, "Sahara and Sudan"; in 1884 annexed to Germany territory in West Africa; died on his return journey, and was buried at Cape Palmas (1834-1885).
Wood, James, ed. Entry for 'Nachtigal, Gustav'. The Nuttall Encyclopedia. https://www.studylight.org/encyclopedias/eng/nut/n/nachtigal-gustav.html. Frederick Warne & Co Ltd. London. 1900.