- Museum number
NICKEL-SILVER CASED LEVER WATCH.
Pin-pallet lever escapement; keyless; manual setting; early model.
White enamel dial; hours I-XII; minutes 15, 30, 45, 60.
- Production date
Diameter: 54.20 millimetres (case)
Diameter: 47.30 millimetres (dial)
Thickness: 21.10 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by Roskopf
Switzerland, c. 1880
Watch with a pin pallet lever escapement
Signature: On the back of the case in a round cartouche is 'ROSKOPF S.GD.G.BREVETE.'
Case: An open face case of nickel. On the outside of the case back in a round cartouche is 'S.GD.G.BEVETTE. ROSKOPF'.Also on the back above the cartouche is STM in a decorative surround. The watch number 15 below the cartouche.
Scratched inside the back is J. de Uverloofe?? 1881 Dubois Coguls? Ettienne 1877 and several other unidentified scratchings but no mark CH as is in the case of registration nos 1958,1201.1094 and 1958,1201.1095.
A bulls eye glass is fitted to the case.
Dial and Hands: An enamel dial with black Roman numerals and minute marks with the minutes numbered at 15, 30, 45 and 60. Hair line cracks in the dial and the edge chipped at I o'clock but no pieces of the enamel missing. The dial is pinned to the front plate. Typical early Roskopf hands of brass with the minute hand with a tail.
Ebauche Marks: None, but scratched on the back plate is 649. Also scratched on the front plate beneath the dial is 95.
Frame: Brass plates, the back plate supported by 3 pillars and secured by screws. Cocks for the escape wheel the pallets and the balance, these all mounted on the sub plate which is fixed to the front plate. The sub plate is split and is provided with a screw, turning which can alter the depth between the escape wheel and the pallets. (See registration nos 1958,1201.1092, 1958,1201.1094 and 1958,1201.1095) for a similar arrangement).
An L shaped bridge covers the barrel ratchet wheel and the winding wheel
Barrel and Mainspring: Going barrel with the brass cover carrying the minute wheel which is mounted friction tight. The barrel bottom scratched 95. Barrel inside diameter 23.5 mm., inside height 3.3 mm
Mainspring height 3.1 mm., thickness 0.28 mm.
Arbor: Diameter 7.0 mm., snailed
Hooking: An outer turn of thicker spring moves from one of the four notches in the barrel wall to the next when the spring is fully wound. The mainspring is hooked to this thicker spring.
Train: The brass wheels with five crossings, the steel escape wheel with four.
Jewelled: The escape wheel and pallets cocks jewelled. The balance with jewel holes and with ruby endstones.
Escapement: A pin pallet escapement, obtuse angle layout, a long lever and a single roller. An elliptical section impulse jewel. A steel escape wheel and lever with steel pallet pins the lever screwed to its staff.
An equal impulse escapement.
Number of teeth embraced 3 ½.
Balance and Spring: A brass three armed balance with a rounded rim. Balance diameter 17.7 mm., thickness 0.7 mm.
The flat spiral blued-steel spring with 11 turns.
Means of Regulation: An index on the balance cock but no markings.
Train Counts and Beat Rate:
Great wheel (barrel) 128 (Rotates once in four hours)
Centre wheel 84 pinion 8
Third wheel 60 pinion 7
Escape wheel 18 pinion 6
Beat Rate 17,280
Motion Work: Cannon pinion 20, minute wheel 80, minute pinion 24, hour wheel 72
Winding system: The stem has the winding pinion pinned to its extension within the case. The winding pinion remains in the case when the movement is removed. The hands are set manually from the front, this being facilitated by the hinged bezel.
Dimensions: Case diameter 53.7 mm., height 21.0 mm.,
Movement diameter 47.8 mm., height 14.7 mm.
Provenance: Formerly in the Ilbert collection.
- Not on display
- Latest: 3 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1091 (Ilbert Collection)
Previous owner/ex-collection number: D45 (Ilbert Ledger)