At an auction in Edinburgh in 2010, the sale 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 in the Sinai Desert in 1883. The trio had been tasked with informal diplomacy...