For hundreds of years ships had been sailing to places far & near without really knowing where they were! Sailors knew how to measure latitude, their location north or south of the equator, but they could not measure longitude, their location east or west of their home port. The key to solving this problem lay in devising a clock that could keep absolutely accurate time while at sea, unaltered by rough water or weather conditions. John Harrison (1693-1776), an Englishman, worked for more than 40 years to create a perfect clock. Harrison won recognition for his work in 1773. This beautiful book takes the reader through the drama, disappointments, & successes that filled Harrison¿s quest to invent the perfect sea clock. Ages 7-10. Illus. Reinforced binding.