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Timekeeping
H4 (ZAA0037)
| Object name: |
Marine timekeeper
We
have 4 objects of this type online
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D0789_1, Marine timekeeper (H4), obverse
© National Maritime Museum, Greenwich, London
About our images
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| Artist/maker: |
John Harrison
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| Date made: |
1759 |
| Place made: |
London, England |
| Materials: |
brass; steel; silver; diamond; ruby; enamel; copper; glass |
| Measurements: |
Diameter: 132 mm |
| Credit: |
National Maritime Museum, Greenwich, London, Ministry of Defence Art Collection |
| Collection: |
Chronometers, precision watches and timekeepers
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| Other views: |
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Description:
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Marine timekeeper, H4. 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. It is shown here at almost actual size. See also; ZAA0034 (H1), ZAA0035 (H2) and ZAA0036 (H3).
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Related terms
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Horology
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The foundation of the Royal Observatory, in 1675, was expressly to discover a method for finding longitude, and this astronomical research required the use of very accurate clocks. More…
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