Longitude Author:Dava Sobel Longitude is the dramatic true story of an epic scientific quest. The "longitude problem" was the thorniest dilemma of the eighteenth century. Lacking the ability to measure longitude, sailors throughout the great ages of exploration had been literally lost at sea. As the heart of Dava Sobel's fascinating brief history of astronomy... more », navigation and clockmaking stand the figure of John Harrison, Yorkshire clockmaker, and his forty-year battle to build the perfect timekeeper and claim the 20,000 pound reward offered by Parliament.« less