In 1882 he visited southern Angola with the Earl of Mayo, and in the following year met Henry Morton Stanley in the Congo, becoming one of the first Europeans after Stanley to see the river above the Stanley Pool. His developing reputation led the Royal Geographical Society and the British Association to appoint him leader of an 1884 scientific expedition to Mount Kilimanjaro. On this expedition he concluded treaties with local chiefs (which were then transferred to the British East Africa Company), in competition with German efforts to do likewise.