- Museum number
NICKEL-SILVER CASED LEVER WATCH.
3/4-plate; going barrel.
Pin-pallet lever escapement; keyless-winding; manual hand set.
White enamel dial; hours I-XII; minutes 15-60.
Diameter: 53.70 millimetres (case)
Diameter: 47.50 millimetres (dial)
Thickness: 21.40 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Switzerland, c. 1910
Watch movement with a pin pallet lever escapement
Case: An open face case of nickel. On the outside of the case back was a cartouche with the legend 'PATENT ROSKOPF' but this is almost entirely rubbed away. Its form can still be seen however on the inside of the case.
Inside the back is an oval cartouche with the identical mark CH as is in the case of registration no. 1958,1201.1094. Also the number 1.
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 between VI and VII o'clock. 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 on the back plate is 'ROSKOPF' in small lettering. A triangular punch mark in the barrel ratchet wheel and keyless wheel bridge. 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 and 1958,1201.1094 for a similar arrangement).
Stamped on the sub plate is an 'O' and an 'H'.
An L shaped bridge covers the barrel ratchet wheel the winding wheel and the end of the ratchet spring.
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: A slipping mainspring. 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: At the escape wheel and pallets. The balance with jewel holes and with ruby endstones. The jewels rubbed in.
Escapement: A pin pallet escapement, obtuse angle layout, a long lever and effectively a double roller. A nickel silver impulse finger. A steel escape wheel and lever, the dart of brass. One of the steel pallet pins is broken off.
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 top balance pivot broken.
The flat spiral blued-steel spring with 11 turns.
Means of Regulation: An index on the balance cock but no other 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 pinned to its extension within the case the winding pinion and this 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: 2 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1095 (Ilbert Collection)
Previous owner/ex-collection number: P293 (Ilbert Ledger)