Tasman National Park Coastline #1, Tasman Peninsula. September 2013. Longitude , Dava Sobel: A bit of background first: the "longitude problem" was one of the trickiest practical and scientific dilemmas of the eighteenth century. Lacking the ability to measure longitude made sailing around on unchartered oceans decidedly dangerous. For example, in October 1707 the English navy lost 2,000 men after the Admiral misgauged their position (by quite some margin). Even more bittersweet was the fact that the very same Admiral had earlier hanged a seaman who – having illicitly kept his own careful log – challenged those who argued that the fleet was in safe waters. This disaster in particular prompted the English government to establish a Board of Longitude and it offered £20,000 – an immense amount for the time – for a solution to the greatest problem of the day. The quest to solve the riddle of longitude is at the heat of this book, which is in alternated moods a history of ast...