This instalment of our list is dominated by the search for Sir John Franklin's missing North-west Passage expedition (see 1845–48). The search began in 1847 and continued intensively until 1854, when Dr John Rae finally found the first clues regarding the fate of the expedition. An important feature of the search was the large number of sledge expeditions, which set out from the searching ships in spring. By this means, many thousands of kilometres of new coastline were discovered in a relatively short period, mainly during the spring months of 1851 and 1853, and much of the Canadian Arctic archipelago, which was largely unknown before 1850, was added to the map. In nearly every case, the sledges were man-hauled by an officer and six or seven seamen. We are listing all of the searches for Franklin, as we listed all North-west Passage expeditions, including some that did not touch Canadian shores.