stop-watch
- Museum number
- 1958,1201.1066
- Description
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MOVEMENT, DIAL AND DUST-CAP OF A LEVER WATCH WITH STOP MECHANISM.
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Full-plate; fusee; Harrison's maintaining power.
Massey-type lever-escapement; stop acts on lever.
White enamel dial; hours I-XII; subsidiary seconds.
Gold spade hour hand; minute hand not original; blued steel seconds hand (later).
Gilt-brass dust-cap.
Case missing.
- Production date
- 1815-1820
- Dimensions
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Diameter: 47.20 millimetres (dial)
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Diameter: 43 millimetres (dust-cap)
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Thickness: 17.40 millimetres
- $Inscriptions
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- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Maker unknown
England, c. 1820
Movement of a ratchet tooth lever stop-watch with a type II Massey roller.
Signature: None.
Case: Missing.
Dial & hands: Flat dial inscribed 'PATENT' below the XII and with a subsidiary seconds dial. Gold spade hour hand, the brass minute hand and the blued-steel seconds hand not original.
Dial-plate: stamped with the letter 'S'.
Dust-cap: stamped 'TB' on the inside.
Movement
Ebauche Marks: none.
Frame: Full plate layout, the back plate supported by four turned pillars. The balance cock is inscribed 'Massey's PATENT' on the table and punched 'TB' on the underside of the foot, the same mark as on the dust cap.(1)
Fusee, Barrel and Mainspring:
Fusee: five-turn fusee with Harrison's maintaining power, the maintaining ratchet wheel of steel.
Barrel: internal diameter 16.8mm, height 4.70mm. The set-up work is in a turned recess on the barrel bridge with a blued-steel ratchet and spring and a polished steel ratchet wheel. Only the foot of the spring survives.
Mainspring: height 4.3mm, thickness 0.20mm.
Barrel Arbor: diameter 5.3mm.
Hooking: Originally square but now round.
Train: Gilded train, the centre wheel solid, the third and fourth with five crossings.
Jewelling: Jewelled bearings for the balance pivots only with a ruby endstone in a wedge in the potence and a diamond endstone in the balance cock.
Escapement: An obtuse-angle layout ratchet tooth lever with a Massey type II roller. There is no draw. The impulse stone is a replacement. The enclosed pallet stones have flat acting faces although the outer faces of both stones are curved along their length. Gilded escape wheel with three crossings.
A mixed escapement.
No .of teeth embraced: 32.
Balance & Spring: A rounded-rim, polished steel, three-arm balance, diameter 21.8mm, thickness 0.75mm. Blued-steel flat spiral spring with six turns.
Means of Regulation: A Bosley regulator, indicating against a divided scale with three stars and 'SLOW' and 'FAST' engraved on the back plate.
Train Counts and Beat Rate:
Great wheel 60 (fusee)
Centre wheel 64 pinion 12
Third wheel 60 pinion 8
Fourth wheel 56 pinion 8
Escape wheel 15 pinion 7
Beat Rate: 14,400
Motion work: cannon pinion 12
minute wheel 48, minute pinion 15
hour wheel 45
Stop mechanism: originally the stop detent acted on the pallet frame but the lever and detent have subsequently been removed, leaving only the stud which pivots in the front plate.
Winding System: Key wound.
Dimensions
Movement: diameter 47.2mm, height 14.8mm, pillar height ? ?? mm.
Provenance: Formerly in the Ilbert collection. Ilbert purchased this movement in Edinburgh in 1930.
Notes:
For a watch with a dust-cap punched TB in cameo see Cat. no. 82 (registration no. 1958,1201.1235).
Exhibited: Newcastle-under-Lyme Museum, 1977. See Professor A. Treherne, 'The Massey Family', cat. no. 31.
- Location
- Not on display
- Condition
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Latest: 3 (2017)
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2 (1994)
- Acquisition date
- 1958
- 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.
- Department
- Britain, Europe and Prehistory
- Registration number
- 1958,1201.1066
- Additional IDs
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Previous owner/ex-collection number: CAI.1066 (Ilbert Collection)
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Previous owner/ex-collection number: F2 (Ilbert Ledger)