By the middle of the nineteenth century, the North-West Passage, a trade route from the Atlantic to the Pacific, had been sought for centuries without success. The Franklin expedition of 1845 became the latest victim, and Irish naval officer Sir Robert John Le Mesurier McClure (1807-73) took part in the attempts to ascertain its fate. His ship, H.M.S. Investigator, spent the years 1850-4 in the Arctic, and in the course of their search for the lost...