Charles Frodsham Box Chronometer
Record status
Individual type · partial
Period
1838-1843
Maker / issuer
Charles FrodshamThis marine chronometer was finished by the London firm of Charles Frodsham between 1838 and 1843. Designed for determining longitude at sea, it features an engraved and silvered brass dial with blued steel hands, Roman numerals, a subdial for seconds, and an up-and-down winding indicator.
According to the Smithsonian Institution, the movement utilizes an Earnshaw spring detent escapement, a helical blued steel balance spring, and a 56-hour spring drive governed by chain and fusee. Housed in a brass bowl with external gimbal mountings, the chronometer is preserved without its outer wooden box, key, or gimbal ring, and was transferred from the U.S. Navy Bureau of Ships.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Type
- Box marine chronometer (without case)
- Maker
- Charles Frodsham
- Duration
- 56-hour
- Escapement
- Earnshaw, spring detent
- Place Made
- United Kingdom: England, London
- Inscription
- CHARLES FRODSHAM / 7 Pavement Finsbury Squr, / London No.1909
- Power Source
- Spring drive with chain and fusee
- Place recorded
- United Kingdom
- Maker / attribution
- Charles Frodsham
Design
- Visible features
- • Cylindrical brass bowl fitted with screw-mounted exterior brass brackets for gimbal suspension. • Engraved and silvered dial featuring Roman numerals, blued steel hands, subsidiary seconds dial, and state-of-wind indicator below 12 o'clock. • Milled brass bezel holding a flat circular glass crystal with chamfered edge. • Dial inscription visible between the center arbor and subsidiary seconds dial: 'CHARLES FRODSHAM / 7 Pavement Finsbury Squr, / London No.1909'.
- Identity and Provenance
- This marine chronometer, identified by serial number 1909, is the work of the firm Charles Frodsham. It was produced between 1838 and 1843 in London, England. The object was transferred to the Smithsonian Institution from the U.S. Navy’s Bureau of Ships. It is currently preserved without its original outer box, gimbal ring, or winding key.
- Dial and Visual Features
- The instrument features an engraved, silvered brass dial. Visual features include blued steel fleur-de-lys hands, a subsidiary seconds dial, and a state-of-wind indicator for the 56-hour duration. The dial is inscribed: 'CHARLES FRODSHAM / 7 Pavement Finsbury Squr, / London No.1909'. It is protected by a flat glass crystal with a small, unpolished chamfer, secured by a milled, screwed brass bezel.
- Mechanism and Construction
- The movement uses an Earnshaw spring detent escapement and a helical, blued steel balance spring. Power is provided by a spring drive with a chain and fusee. The movement is enclosed in a brass bowl. A sprung cylindrical inner bowl is present, serving as a dust cover. The exterior of the bowl features brass fittings for gimbal suspension.
Identification
- Serial number
- 1909
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: The outer wooden chronometer case, gimbal ring, and winding key are missing as noted by the source.
- Research required: Internal movement components including the Earnshaw escapement and helical balance spring are not visible in the photograph.