Arnold & Dent Box Chronometer

This instrument is a specialized timekeeper designed for finding longitude at sea. Its form is that of the standardized 19th-century marine chronometer. It was transferred to the Smithsonian from the U.S. Coast & Geodetic Survey. John Roger Arnold, son of chronometer maker John Arnold, and Edward John Dent (1790-1853) were in business together from 1830-1840 at 84 Strand, London. Charles Frodsham took over Arnold’s business after Arnold’s death in 1843. E. J. Dent, who had started making chronometers in 1814, continued in business until his death, when others continued the firm under various names and at various addresses. The business continues today.
Mechanism details:
Escapement: Earnshaw, spring detent
Duration: 48-hour
Power source: Spring drive with chain and fusee
Balance spring: helical, blued steel
Winding key, stamped "1131"
Bowl details:
Brass bowl, fitted with a sprung cylindrical inner bowl as a dust cover (original work); "1131" stamped on bottom inside of bowl
Dimensions: 4.17" dia. across bezel x 2.7"
Brass fittings, brass gimbal
Bezel screwed and milled
Crystal convex, plain
Dial details:
Engraved and silvered brass
Indicates hours, minutes, seconds, winding level up and down
Inscription: "ARNOLD & DENT, / 84. Strand, London No 1131”
Hands: Gold, spade, with blued steel seconds hand
Case details:
Three-part, glazed center section
Brass side handles and escutcheon
Bone roundel at front
Inscriptions: "1131" engraved on roundel on case. "U.S.C.S." engraved on case lid
1. Gould, Rupert T. The Marine Chronometer. London: Holland Press, 1960.
2. Mercer, Tony. Chronometer Makers of the World. Essex: NAG Press, 1991.
3. Mercer, Vaudrey. John Arnold & Son. London: Antiquarian Horological Society, 1972.
4. Mercer, Vaudrey. Edward John Dent and His Successors. London: Antiquarian Horological Society, 1977.
5. Whitney, Marvin E. The Ship's Chronometer. Cincinnati: American Watchmakers Institute Press, 1985.
Object Name
Box Chronometer
date made
Arnold & Dent
Physical Description
brass (overall material)
glass (overall material)
mahogany (container material)
steel (overall material)
overall: 6 1/8 in x 6 1/2 in x 6 in; 15.5575 cm x 16.51 cm x 15.24 cm
overall - from catalog card: 6 1/8 in x 6 in x 6 3/4 in; 15.5575 cm x 15.24 cm x 17.145 cm
place made
United Kingdom: England, London
ID Number
catalog number
accession number
Time and Navigation
Measuring & Mapping
See more items in
Work and Industry: Mechanisms
Time and Navigation
Time and Navigation, National Air and Space Museum
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
U.S. Coast and Geodetic Survey
Additional Media

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