In the annals of nineteenth-century African exploration, the great names still stir the senses: Burton, Livingstone, Stanley, Park, Speke, Baker and Cameron are justly celebrated to this day in the theatre of the Royal Geographical Society (RGS), the learned society that championed scientific discovery and captivated the Victorian public with tales of derring-do in distant deserts, far-flung poles and fever-filled jungles.

Cognoscenti will quickly spot one name missing from that impressive list. Although his scientific achievements far eclipsed those of his contemporaries, he was never a household name nor did he ever receive the public acclaim that he felt was his due. Recognised by the Royal Geographical Society, which awarded him