SPEKE, John Hanning (1827-1864). What Led to the Discovery of the Source of the Nile. London: William Blackwood, 1864. 8vo (218 x 138 mm). 2 lithographed folding maps, wood-engraved frontispiece. (Lacking half-title, preliminary leaves with minor pale foxing.) Later green morocco gilt by Pfister (spine slightly sunned). FIRST EDITION, which Speke published in response to Burton's publication of The Nile Basin in 1864 (see lot 33). The Burton-Speke controversy was ignited when Speke took sole credit for the discovery of Lake Victoria (see previous lot); their theories on the origin of the Nile River differed. Speke and Burton were set to debate their findings for the Royal Geographical Society, before Speke's untimely death.