The sale at auction in Edinburgh in 2010 of an old walking stick belonging to a British officer, Captain Gill, shed new light on one of the mysterious crimes of the Victorian era.

Captain William Gill and his companions, the noted Arabist Professor Edward Palmer of Cambridge University and a young naval lieutenant, Harold Charrington, were killed in an ambush by Bedouin Arabs in the Sinai Desert in 1883. The trio had been tasked with informal diplomacy in the region, specifically to prevent the Arab sheikhs from joining the Egyptian rebels and to secure their non-interference with the...