Hamilton Model 21 Marine Chronometer
Record status
Individual type · partial
Period
1959-1965
Maker / issuer
Hamilton Watch CompanyThis Hamilton Watch Company marine chronometer features an Earnshaw spring detent escapement housed in a brass bowl suspended within a gimbal system inside a brass-bound mahogany box.
The silvered dial has black-painted brass hour and minute hands, a blued steel seconds hand, an up-and-down indicator below 12 o'clock, and a subsidiary seconds dial above 6 o'clock inscribed with serial number 2E10228. Sourced by the British Museum in 1988 from Raymond Mellor, former Managing Director of Hamilton's U.K. branch, source notes report the chronometer was assembled specifically for him from the factory's final available parts.
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
- Gimballed marine chronometer
- Maker
- Hamilton Watch Company
- Escapement
- Earnshaw spring detent
- Jewel Count
- 14 jewels
- Museum Number
- 1988,0410.2
- Place recorded
- United States
- Acquisition Year
- 1988
- Production Place
- Lancaster (Pennsylvania)
- Maker / attribution
- Hamilton Watch Company
Design
- Visible features
- • Silvered dial with black Arabic numerals and railway minute track • Up-and-down indicator subdial positioned below 12 o'clock • Gimballed brass bowl mounted inside an open brass-bound mahogany box • Printed instruction plaque titled 'NOTICE' affixed to the inside of the lid • Brass winding tipsy key resting in the upper right corner fitting
- Construction and Housing
- The movement is housed in a brass bowl mounted within a gimbal system, secured inside a brass-bound mahogany box. The box features continuous piano hinges, cast carrying handles that are not recessed, and a glazed panel in the top lid, which includes a brass signature plate. A tipsy key is stored in a corner gusset. Internal components include a nickel-silver frame with straight-line wave decoration. The architecture includes a three-pillar back plate design, where the fourth pillar position is omitted. The brass bowl utilizes a spring-loaded cover to protect the winding aperture.
- Provenance and Documentation
- The chronometer was acquired by the British Museum in 1988. Information regarding its specific assembly history is based on claims by the seller, Raymond Mellor, former Managing Director of the Hamilton Watch Company's U.K. branch, who stated the unit was finished for him using final parts available at the U.S. factory. Catalogue documentation from the British Museum places the production of the instrument within the 1959–1965 timeframe, with specific notes suggesting a date of circa 1962.
- Dial and Escapement Mechanics
- The flat, silvered dial features black-painted brass hour and minute hands alongside a blued steel seconds hand. An up-and-down indicator is located in the top half, with a subsidiary seconds dial at the bottom. The movement utilizes an Earnshaw-type spring detent escapement, incorporating a ruby impulse pallet with a radial face. The balance assembly consists of an ovalising uncut balance with a stainless steel rim and invar arm. It is powered by a Ni-Span-C spring comprising 14 full turns, with fine adjustment achieved through timing nuts set to the side of the balance arm.
Identification
- Reference
- Model 21
- Serial number
- 2E10228
- 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: Internal nickel-silver frame, fusee mechanism, and balance assembly are fully enclosed and not directly visible in the image
- Research required: Assembly from final factory parts is source-reported by seller Raymond Mellor
- Research required: Production date is catalogued broadly as 1959–1965, with catalogue text proposing circa 1962