- Museum number
SILVER-CASED LEVER WATCH WITH DIGITAL TIME INDICATION.
Bar movement; going barrel.
Rocking bar keyless winding and hand-set.
Club-tooth lever escapement; uncut bi-metallic balance.
White enamel dial with hours and minutes in silvered aperture.
Engine-turned silver case with plain escutcheon surrounded by foliate scrolls.
- Production date
Diameter: 50.40 millimetres (case)
Diameter: 37.60 millimetres (dial aperture)
Thickness: 18.50 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by G T.(1)
Switzerland c. 1885
Silver cased digital display watch with club tooth lever escapement
Signature: On the dial "G T Systems Brevete", on the barrel bridge "G T" and "PATENT".
Case: Silver open face case, marked 'G T' with a bear, (the quality mark for Berne) and 0.875. The case numbered 292716. The back engine turned with a shield in the centre, the inner back with "ECHAPPEMENT ANCRE 15 RUBIS Ligne droite No 292716" surrounded by an engine turned border.
Dial and Hands: An enamel dial with an aperture for the hours and minutes and a subsidiary seconds dial. This dial badly chipped. A secondary silvered dial with another sunk subsidiary seconds dial and further apertures for the hours, ten of minutes and minutes. Blued-steel seconds hand.
Ebauche Marks: 471
Frame: A bar movement with a frosted gilt finish.
Barrel and Mainspring: The going barrel: I. diameter 17.2 mm., height 2.75 mm.
Mainspring: height 2.55 mm., thickness 0.25 mm.
Arbor: diameter 5.5 mm., snailed.
Hooking: a pressed in tongue
Train: The brass wheels gilded one side only and with five crossings. The steel escape wheel with four.
Jewelled: From the third onwards, the jewels rubbed in. Ruby endstones for the balance pivots.
Escapement: Club tooth lever, straight line layout, short lever, single roller, impulse pin elliptical. Pallet stones covered, convex on the acting faces. Pallets counterpoised. The escape wheel steel, polished both sides and with the tooth tips chamfered.
A mixed escapement.
Number of teeth embraced 3½.
Balance: An uncut bimetallic balance diameter 17.3 mm., thickness 0.95 mm. Blued-steel flat spiral spring of 15½ turns.
Means of Regulation: Index on the balance cock registering against a divided scale with engraved 'AVANCE RETARD'.
Train Counts and Beat Rate:
Great wheel (barrel) 80
Centre wheel 80 pinion 10
Third wheel 60 pinion 10
(The top pivot of this wheel pivots in a post which supports a wheel with 8 teeth and is linked to the third wheel by an open spring. The teeth of this wheel rests on the fourth wheel arbor which is made like a duplex balance staff with a passing hollow. At each revolution of the fourth pinion i.e. once a minute, one of the eight teeth of the spring-biased wheel will pass and allow this wheel to move forward in minute steps thus driving the minute disc. The rest of the action is identical to that in Cat. no. 0-0 (L½).
Fourth wheel 60 pinion 8
Escape wheel 15 pinion 6
Beat Rate: 18,000
Winding System: Conventional side set positive keyless work. The lever that operates the sliding pinion is, most unusually, biassed by a helical spring which is trapped in a recess that is half in the front plate and half in the barrel bridge.
Dimensions: Case diameter 50.7 mm., height over the glass 18.0 mm.
Movement diameter 43.9 mm., height 11.2 mm.
Provenance: Formerly in the Ilbert collection. This was purchased by Ilbert from Gould in August 1947.
(1) This is the mark of the firm Thommen S.A.
- Not on display
- Latest: 3 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1100 (Ilbert Collection)
Previous owner/ex-collection number: Q136 (Ilbert Ledger)