Thomas Mercer Two-Day Marine Chronometer, No. 17989
Record status
Individual type · partial
Period
circa 1940s
This two-day marine chronometer by Thomas Mercer Ltd of St Albans is housed in a fitted wooden transport box with brass gimbals. The silvered dial features black Roman hour numerals, blued steel hands, an up-and-down state-of-wind indicator dial, and a continuous subsidiary seconds register.
The seconds dial incorporates an unusual open cut-out displaying the seconds wheel mechanism. According to the seller, the brass movement features a chain fusee and spring detent escapement, bearing serial number 17989, which is associated with production around the 1940s.
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
- Two-day marine chronometer
- Duration
- 2 day
- Escapement
- Spring detent
- Dial cut out
- Aperture showing seconds wheel
- Serial number
- 17989
- Place recorded
- United Kingdom
- Maker / attribution
- Thomas Mercer Ltd
Design
- Visible features
- • Silvered dial with state-of-wind subdial below 12 o'clock and an open aperture at the 6 o'clock seconds register revealing brass gearing • Dial signed 'THOMAS MERCER LTD / ST. ALBANS, ENGLAND' and numbered '17989' within the state-of-wind indicator • Gimballed brass bowl mounted inside an open wooden box with brass hardware and winding key post visible • Spade-style blued steel hands against black Roman numeral hour indices
- Dial and Visual Architecture
- The instrument features a circular silvered dial fitted with blued steel spade hands set against black Roman numeral hour markers. Positioned below the 12 o'clock marker is an up-and-down state-of-wind indicator dial, paired with a subsidiary seconds register positioned at 6 o'clock. The dial incorporates an open cut-out aperture at the seconds register through which the brass gearing of the seconds wheel is visible. Dial inscriptions include 'THOMAS MERCER LTD / ST. ALBANS, ENGLAND' and movement number '17989' located within the state-of-wind indicator register.
- Casework and Chronological Context
- The chronometer is housed within an inner wooden box and is reported by the seller to include its original outer 'cutter travel box' equipped with a leather strap and buckle. The outer travel container is not shown in the primary photograph. Dating for the instrument varies across the listing source: the seller states serial number 17989 suggests a 1947 production date, the declaration dates the piece to the 1940s, and the listing header cites 1920–1940.
- Reported Movement and Technical Specification
- According to the seller's description, the movement is of two-day duration and incorporates a chain fusee along with a spring detent escapement. As the movement plates and interior mechanism are enclosed within the brass bowl, these specific technical details derive from the listing text rather than direct examination. The brass bowl is mounted in brass gimbals inside an open wooden box, complete with visible brass mounting hardware and a winding key post.
Identification
- Reference
- SA683094
- Serial number
- 17989
- 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: Date is estimated by the seller (stated variously as 1920-1940, 1940s, or 1947)
- Research required: Outer cutter travel box mentioned in the listing description is not visible in this photograph