Timekeeping, Chronometers, precision watches and timekeepers

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H3

ZAA0036
Timekeeping

Object connections:

Collection Timekeeping, Chronometers, precision watches and timekeepers
ExhibitionsTime and Longitude, Ships, Clocks & Stars: The Quest for Longitude
User collections Harrison by kubera@gml.cz
Harrison by swettengl
The Board of Longitude by Richard_Dunn
John Harrison by NMMCollections
Gallery locationROG (Floor plans)
PeopleProvenance: Royal Greenwich Observatory

Object details:

Object ID ZAA0036
Description 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).
Date made 1757

Artist/Maker Harrison, John
Place made London
Credit National Maritime Museum, Greenwich, London
Materials brass; bronze; steel; glass
Measurements Overall display height: 622 mm
Parts
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