Harrison moves to London John Harrison moved to London in 1736 to continue production of his marine timekeepers in the hope of winning the £20,000 Longitude Prize. The prize was being offered to whoever could provide a solution to the problem of determining longitude at sea. Image Credit England: Tom King's London Coffee House represented in William Hogarth's 'Four Times of the Day', 1736. Credit: Pictures from History / Bridgeman Images
