F7024-009

Harrison's marine timekeeper H4 Long Caption: This is Harrison's prize-winning longitude watch, completed in 1759. Harrison had been working on improving watches as a sideline to his development of the much larger H3. In 1753 a pocket watch was made to Harrison's design by watchmaker John Jefferys. This went so well that Harrison began to realise that it pointed to the longitude solution - not in H3 but in smaller watches. Work began on H4 in 1755 and, with its very stable, high frequency balance, it proved the successful design. Credit line: © National Maritime Museum, Greenwich, London Object: ZAA0037 Artist: John Harrison Date: 1759 Medium: brass; steel; silver; diamond; ruby; enamel; copper; glass Size: diameter: 132 mm Click here to buy a bespoke print of this image.