Accession No
2581
Brief Description
chronometer, in gimbal and fitted box, by Robert Molyneux, English, 1828
Origin
England; London; 44 Devonshire Street
Maker
Molyneux, Robert
Class
navigation; horology
Earliest Date
1828
Latest Date
1828
Inscription Date
Material
metal (brass, steel, silver); glass; wood (mahogany); ivory
Dimensions
Diameter of bezel 103mm; box 159 x 160 x 171mm
Special Collection
Provenance
Transferred from Institute of Astronomy, University of Cambridge, Cambridge, England, 06/1980.
Inscription
‘Robt Molyneux. - 44 Devonshire Street
London No 1114.’ (on dial)
‘W’ (ivory plate on box)
Description Notes
Chronometer, in gimbal and fitted box, by Robert Molyneux, English, 1828.
2-day marine chronometer. Movement with fusee, Earnshaw spring-detent escapement, compensation balance with segmental weights, overspring with blued steel, helical balance spring with terminal curves. Dome-shaped glass bezel. Slung in gimbals, in brass-bound mahogany box with brass handles, glazed window with hinged cover and inlaid ivory plate. Silvered 24-hour dial with Arabic numerals and subsidiary seconds. Brass winding key.
References
Joshua Nall; ‘Navigational Arts’; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge; 2020: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/astronomy-and-empire/navigational-arts
Events
Description
Chronometers are very accurate clocks which were taken on board ship as a means to find longitude. A ‘Two Day’ chronometer is one that must be wound every two days.
The chronometer is set to show time at the port of departure, and during the voyage is compared with the ship’s local time as given by the sun. The earth rotates around its axis – 360° in longitude – every 24 hours, or 15° every hour. Thus a difference of four minutes between the time shown by the chronometer and local time by the sun is equal to a change of 1° of longitude.
04/08/2008
Created by: Dr Anita McConnell on 04/08/2008
FM:39679
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