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The Encyclopedia of Horology

Marine chronometer · Two-day marine chronometer

Thomas Mercer Ltd. Cased Two-Day Marine Chronometer

Partially verified

This 20th-century English two-day marine chronometer is attributed by the source to Thomas Mercer Ltd. of St. Albans, England, and is marked with serial number 19920. The instrument is housed within a gimballed brass bowl set into a wooden transport case displaying dovetail joinery, a keyhole escutcheon, and an affixed retailer plaque citing F.C.R. Wiggins in Reading. The auction condition report notes that the clock does not run when wound and exhibits minor rusting beneath the bowl, alongside minor surface wear on the timber case.

English cased two-day marine chronometer attributed to Thomas Mercer Ltd., shown in its open wooden case.
English cased two-day marine chronometer attributed to Thomas Mercer Ltd., shown in its open wooden case. — Freeman's. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
freemansauction.com
Category
Marine chronometer · Two-day marine chronometer
Maker / attribution
Thomas Mercer Ltd.
Reference
Not recorded
Catalogue / lot identifier
138
Source-reported date
20th Century
Country
United Kingdom
Source-reported serial
19920

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Identity and Attribution

This marine chronometer is attributed to Thomas Mercer Ltd. of St. Albans, England, and is identified by serial number 19920.

The object is recorded as a 20th-century two-day marine chronometer, with a retailer plaque identifying 'F.C.R. Wiggins' of Reading.

Evidence for this section
  • “Thomas Mercer Ltd., St. Albans, England, 20th Century”
  • “serial no. 19920.”
  • “case with affixed plaque Supplied by / F.C.R. Wiggins / 15 Oxford St. Chamber / Reading / No. 19920.”

Construction and Housing

The chronometer is housed within a wooden case with a hinged lid. The movement is contained in a circular brass bowl mounted on gimbals.

The case features a keyhole escutcheon on the front face and includes an internal locking thumbscrew.

Evidence for this section
  • “Dovetail-jointed wooden box with an open, hinged glazed lid supported by brass hardware.”
  • “Circular brass bezel and bowl mounted within gimbal suspension.”
  • “Vertical knurled locking thumbscrew mounted at the interior right corner of the box.”
  • “Keyhole escutcheon positioned centered on the front face of the lower wooden section.”

Condition

The source states that the clock does not run when wound. Reported defects include minor rusting to the underside of the clock case and minor scuffs and surface wear to the wooden case.

Visibility of the dial and hands is limited in the provided photography.

Evidence for this section
  • “Clock currently does not run when wound.”
  • “Wooden case with minor scuffs and surface wear.”
  • “Minor rusting to underside of clock case.”

Open research questions

  • What is the mechanical cause for the failure to run when wound?
  • Can the serial number 19920 be verified against Thomas Mercer factory production records?
  • What is the historical nature of the retailer F.C.R. Wiggins?

Source evidence

Recorded claims and source quotations for Thomas Mercer Ltd. Cased Two-Day Marine Chronometer
FieldSource-reported valueSource quotation
Maker attributionThomas Mercer Ltd., St. Albans, England“Thomas Mercer Ltd., St. Albans, England, 20th Century”
Serial number19920“serial no. 19920.”
Retailer plaqueSupplied by / F.C.R. Wiggins / 15 Oxford St. Chamber / Reading / No. 19920“case with affixed plaque Supplied by / F.C.R. Wiggins / 15 Oxford St. Chamber / Reading / No. 19920.”
Overall diameter10 1/2 inches“Overall diameter 10 1/2 inches.”
Case dimensionsHeight 6 5/8 x width 7 x depth 7 1/4 inches“Height of case 6 5/8 x width 7 x depth 7 1/4 inches.”
Operational conditionDoes not run when wound“Clock currently does not run when wound.”
Overall diameter10 1/2 inches“Overall diameter 10 1/2 inches.”
Case dimensionsHeight 6 5/8 x width 7 x depth 7 1/4 inches“Height of case 6 5/8 x width 7 x depth 7 1/4 inches.”

Visible details

  • Dovetail-jointed wooden box with an open, hinged glazed lid supported by brass hardware.
  • Circular brass bezel and bowl mounted within gimbal suspension.
  • Vertical knurled locking thumbscrew mounted at the interior right corner of the box.
  • Keyhole escutcheon positioned centered on the front face of the lower wooden section.

Research qualifications

  • The dial and hands are largely unreadable due to the oblique viewing angle and lighting in the catalog photograph.
  • The source reports the clock does not run when wound and shows minor rusting on the underside of the clock case.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

An English Cased Two-Day Marine Chronometer | Freeman's

Reviewed 2026-10-25 · Record bb550ef52a

Terms in this record

Glossary explanations for terms named in this object’s record.

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