- Museum number
NICKEL CASED TIMER/STOP-WATCH.
Lever escapement; keyless.
Black metallized dial with luminous figures.
Open-face domed case.
Diameter: 57.90 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Switzerland, c. 1930
Gun-fire measuring watch with a club tooth lever escapement.
Signature: The movement marked 'SWISS MADE PATENT' 73392/93 74101 and with the Helvetia cross.
Case: Nickel case, open face with snap on bezel and hinged inner and outer backs. Markings on the inside of these backs have been milled off. A government broad arrow on the back of the case and the number 2262.
Dial and hands: Black dial, the centre seconds hand revolves once in 3 seconds and the dial is divided into 50 with each alternate mark numbered in 100 steps from 100-2500. All markings in white but overlaid with luminous compound. A subsidiary dial with a hand that revolves in 2 minutes although there are only four markings 0, 2500, 5000, and 7500. On the back of the dial but not under the enamel 'Sl'. Steel hands painted white and then covered in luminous paint.
Ebauche Marks: 74101 70
Frame: 1/2 plate movement, a bridge for the barrel, centre and third wheels, with on the bridge a cock for the chronograph centre wheel and the ancillary wheel, this cock numbered 101. Cocks for the balance, pallets, escape and fourth wheels.
Barrel and Mainspring: A recessed cover to the going barrel. Barrel I. diameter 16.5 mm., height 1.9 mm.
Mainspring: height 1.9 mm., thickness 0.25 mm.
Arbor diam 5.4 mm snailed.
Hooking: pressed in from the barrel wall.
Train: Wheels of brass gilded, centre, third and fourth wheels with five crossings, the steel escape wheel with four.
Jewelled: From the third wheel onwards. Ruby endstones to the balance.
Escapement: Club tooth lever, straight line layout, short lever, double roller, impulse pin D shaped. Pallet stones exposed the acting faces flat. Escape wheel of steel.
An equidistant locking escapement.
No. of teeth embraced 3 ½.
Balance and Spring: A monometallic balance, the rim with a serrated edge with 8 screws standing vertically from the rim. The balance diameter 12.4 mm., rim height 0.5 mm. A 'self compensating' flat spiral spring with 7 1/4 turns and a terminal curve. The spring diameter about 2/3 the diameter of the balance.
Means of Regulation: Micrometer index on the balance cock registering against a divided scale with 'F S' and 'A R'. A whiplash spring biasses the index against a fine pitch screw.
Train Counts and Beat Rate:
Great wheel (barrel) 84
Subsidiary recorder wheel 40
Inter wheel 30
Centre wheel 80 pinion 12
Third wheel 80 pinion 10
Fourth wheel 60 (Drives A) pinion 10
Escape wheel 15 pinion 6
Beat rate of balance 100th second
Rocking pinion 10 (A) with fine cut pinion 27 mm diam. Centre seconds wheel 8.1 mm diam so therefore A revolves once a second since the ratio is 3:1.
Motion work: Not fitted by maker as not applicable.
Chronograph work: Pressure on the winding button indexes the castle wheel that controls the three functions stop, start and zero. The balance is stopped and started by two separate levers with pins that impinge on the balance rim. One lever stops the balance and as the stop is withdrawn the other lever brushes pass the rim and gives the balance a flick so as to start the watch.
Winding System: Rocking bar keyless work, the intermediate pinion that would have meshed with the minute left off as not applicable.
Dimensions: Case diameter 58.0 mm., height 16.0 mm., over the glass.
Movement diameter 41.9 mm., height 11.0 mm.
Provenance: Formerly in the Ilbert Collection. Ilbert purchased this from Malcolm Gardener in December 1949.
Note: See registration no. 1958,1201. 1132 for details of the use of these watches.
- Not on display
- Latest: 2 (Feb 1995)
- Acquisition date
- Acquisition notes
- Following the successful acquisition of the celebrated Ilbert collection of clocks (1958,1006 collection), prints and other related materials made possible by the generous donation of funds by Gilbert Edgar CBE Ilbert's watches were then acquired using funds provided by Gilbert Edgar, public donations and government funds.
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1491 (Ilbert Collection)
Previous owner/ex-collection number: Q168 (Ilbert Ledger)