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An image showing 'H1 - Front View'
An image showing 'Harrison's Marine Chronometer number 3 (H3) - 3/4 front view'
An image showing 'Marine timekeeper (H3), front'
An image showing 'Harrison's Marine Chronometer number 3 (H3) - view of front'
An image showing 'Harrison's Marine Chronometer number 3 (H3) - 7/8 front view'
An image showing 'Marine timekeeper (H3) with case'
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An image showing 'Marine timekeeper (H3), back and side'
An image showing 'Marine timekeeper'
An image showing 'H3 - Cutout image of D6785-5'
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An image showing ''
An image showing ''
An image showing ''
An image showing ''
An image showing 'H1 - 3/4 Raised Front'
An image showing 'H1 - Compensation Assembly'
An image showing 'H1 - Dial'
An image showing 'H1 - Train - General View From Front'
An image showing 'H1 - Train - Detail View'
An image showing 'H1 - Remontoire, Balance, Ribbons & Escapement'
An image showing 'H1 - Compensation'
An image showing 'H1 - Compensation Detail'
An image showing 'H1 - Side View From Left'
An image showing 'H1 - Fusee & Remontoire'
An image showing 'H1 - Rear View'
An image showing 'H1 - Rear Bearing Of Isochroniser'
An image showing 'H1 - Rear Side View'
An image showing 'H1 - Fusee & Chain Barrell'
An image showing 'H1 - Balance Springs & Bimetal'
An image showing 'H1 - Upper Escapement Pallett Raised View'
An image showing 'H1 - Upper Escapement Pallett Lower View'
An image showing 'H1 - Glazed Case Front'
An image showing 'H1 - Glazed Case 3/4 Raised'
An image showing 'H1 - Glazed Case Side View'
An image showing 'H1 - Glazed Case Rear View'
An image showing 'H1 - Glazed Case Joint Detail'
An image showing 'H1 - Glazed Case Joint & Edge Detail'
An image showing 'H1 - Glazed Case Top Corner Detail'
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H3

Marine timekeeper, H3. Started in 1740, this third timekeeper took Harrison nearly 19 years to build and adjust, although it was not to win him the great longitude prize: he found that he just could not persuade the two large, heavy, circular balances to keep time well enough. Nevertheless, H3 incorporates two extremely important inventions, both relevant today: the bimetallic strip (still in use worldwide in thermostats of all kinds) and the caged roller bearing, a device found in nearly all modern mechanical engineering. See also; ZAA0034 (H1), ZAA0035 (H2) and ZAA0037 (H4).
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Object Details

ID: ZAA0036
Collection: Timekeeping
Type: Marine timekeeper
Display location: Display - ROG
Creator: Harrison, John
Places: Greenwich
Date made: 1757; 1759
Exhibition: Time and Longitude; Ships, Clocks & Stars: The Quest for Longitude
People: Royal Greenwich Observatory
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall display height: 622 mm
Parts: H3