Pocket watch · Deck chronometer pocket watch

Charles Frodsham 18K Yellow Gold Duo-In-Uno Chronometer Pocket Watch No. 09792

Partially verified

This open-faced chronometer pocket watch in 18K yellow gold is catalogued to Charles Frodsham circa 1918. Measuring approximately 60 mm in diameter, the timepiece features a silver dial with Roman numerals, an up/down power reserve indicator below 12 o'clock, and a subsidiary seconds dial at 6 o'clock. The dial is signed 'Chas Frodsham No 09792 AD Fmsz', referencing the maker's historic cryptogram. According to the source, the watch is powered by a frosted gilded three-quarter plate chronometer movement equipped with a detent escapement and a Duo-In-Uno hairspring.

Dial view of Charles Frodsham 18K yellow gold pocket chronometer No. 09792 — Antiquorum. Rights pending — permission not yet requested. Original source

Catalogue identity

Source: catalog.antiquorum.swiss
Category: Pocket watch · Deck chronometer pocket watch
Maker / attribution: Charles Frodsham
Reference: Not recorded
Catalogue / lot identifier: 130
Source-reported date: circa 1918
Country: United Kingdom
Source-reported serial: 09792

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 Dial Configuration

This timepiece is an open-faced chronometer pocket watch catalogued to Charles Frodsham circa 1918 under serial number 09792. The silvered dial features black Roman numerals, an outer track with secondary 24-hour hour markings, and blued steel hands including a spade hour hand, minute hand, and smaller pointers for registers.

A subsidiary dial for running seconds is positioned at 6 o'clock, complemented by an up/down power reserve indicator beneath 12 o'clock. Across the center, the dial is signed 'Chas Frodsham No 09792 AD Fmsz.' The source notes explain that the 'AD Fmsz' cipher represents 'Anno Domini 1850' and was applied by the firm to mark its top-tier production.

Evidence for this section

“Dial signed across the center 'Chas Frodsham No 09792 AD Fmsz.'”
“Subsidiary dial for running seconds at 6 o'clock and an up/down indicator beneath 12 o'clock.”
“The “AD Fmsz” marking (a cryptogram signifying “Anno Domini 1850”) was used by the firm from the mid-19th century onward as a hallmark of their highest-quality work.”

Case Construction and Dimensions

The open-faced case is constructed in 18K yellow gold, measuring 60 mm in diameter with an approximate weight of 200 grams. Visible exterior features include fluting on the winding crown and an arched suspension bow in yellow metal.

The cataloguer lists matching case and movement numbers as 09792, noting signature on the dial, case, and movement. The source condition report grades the case as '3-8 Good Slightly scratched.'

Evidence for this section

“Diameter 60mm.”
“Weight 200gr. (approx.)”
“Case No. 09792”
“Visible fluting on the winding crown with an arched suspension bow in yellow metal.”

Reported Movement and Technical Characteristics

Internal movement characteristics are documented through the auctioneer's catalogue description rather than visible observation. The caliber is reported as a keyless, frosted gilded three-quarter plate chronometer movement featuring a detent escapement and a Duo-In-Uno hairspring.

The movement plate is engraved: 'By Appointment to the King, Chas Frodsham, 27 South Molton St. London, No 09792, AD Fmsz.' The cataloguer grades the movement as '3* Good' with an overhaul recommended at the buyer's expense, and describes the hands as original.

Evidence for this section

“Caliber Frosted gilded three-quarter plate chronometer movement, with duo-in-uno hairspring”
“movement plate engraved: “By Appointment to the King, Chas Frodsham, 27 South Molton St. London, No 09792, AD Fmsz.””
“Movement: 3* Good Overhaul recommended, at buyer's expense”
“HANDS Original”

Open research questions

What specific London hallmark date letter is stamped inside the 18K gold case to confirm the circa 1918 production date?
Do Charles Frodsham ledger records provide the original delivery date or client for chronometer No. 09792?

Source evidence

Recorded claims and source quotations for Charles Frodsham 18K Yellow Gold Duo-In-Uno Chronometer Pocket Watch No. 09792
Field	Source-reported value	Source quotation
Movement Number	09792	“Movement No. 09792”
Case Number	09792	“Case No. 09792”
Caliber	Frosted gilded three-quarter plate chronometer movement, with duo-in-uno hairspring	“Caliber Frosted gilded three-quarter plate chronometer movement, with duo-in-uno hairspring”
Diameter	60mm	“Diameter 60mm.”
Weight	approx. 200gr.	“Weight 200gr. (approx.)”
Movement Plate Address	27 South Molton St. London	“27 South Molton St. London”
Reported Hands Status	Original (catalogued)	“HANDS Original”

Visible details

Silvered dial with black Roman numerals and an outer track with secondary 24-hour hour markings.
Blued steel hands including a spade hour hand, matching minute hand, and smaller pointers for registers.
Subsidiary dial for running seconds at 6 o'clock and an up/down indicator beneath 12 o'clock.
Dial signed across the center 'Chas Frodsham No 09792 AD Fmsz.'
Visible fluting on the winding crown with an arched suspension bow in yellow metal.

Research qualifications

Internal movement features including the detent escapement and Duo-In-Uno hairspring are source-reported and not visible in the provided image.
Dial exhibits light surface spotting and scratches consistent with auction condition notes.

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

Consulted source

CHARLES FRODSHAM, DUO-IN-UNO, CHRONOMETER, POCKET WATCH, 18K YELLOW GOLD | Important Modern & Vintage Timepieces | Hong Kong May 31, 2026

Reviewed 2026-10-21 · Record 3cc33fdbe5

Terms in this record

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