- Museum number
MOVEMENT AND DIAL OF A LEVER WATCH.
Full-plate; fusee; ratchet-tooth lever-escapement.
White enamel dial, hours I-XII, subsidiary seconds.
- Production date
Diameter: 33.50 millimetres (back-plate)
Diameter: 38.20 millimetres (dial)
Thickness: 11.90 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by John Roger Arnold and Edward John Dent.
London, c. 1845
Movement of a ratchet tooth lever watch.
Signature: 'Arnold and Dent No. 6783' on the barrel bridge and 'London' on the back plate.
Dial & Hands: Flat dial with a subsidiary seconds dial. On the back of the dial in the counter-enamel 'S3'. The hands are missing.
Dial-plate: Not intended, the dial is pinned directly to the front plate.
Dust-cap: None intended.
Ebauche Marks: 6783 10 2
Frame: A full plate layout, the back plate supported by four turned pillars. The pillar positioned between the escapement and the barrel now retained by a screw. The balance cock with engraved floral decoration and a mask. Both the balance cock and the back plate are stamped '6783'.
Fusee, Barrel and Mainspring:
Fusee: five-turn fusee without maintaining power.
Barrel: internal diameter 14.6 mm, height 3.0 mm.
Mainspring: height 2.8 mm, thickness 0.23 mm.
Arbor: diam 4.35 mm, not snailed.
Hooking: originally square but now round.
Train: Wheels gilded, the centre wheel solid, the third and fourth wheels with five crossings.
Jewelling: Jewelled bearings for the balance pivots only with a ruby endstone in a wedge in the potence. The jewels in the balance cock are missing.
Escapement: A right-angle layout ratchet tooth lever escapement with short lever, single roller and round impulse pin. The enclosed pallet stones have convex impulse and locking faces. The gilded escape wheel has three crossings.
An equal impulse escapement.
No. of teeth embraced. 32
Balance & Spring: A rounded-rim, polished steel, three-arm balance, diameter 17.0 mm, thickness 0.7 mm. A blued-steel flat spiral spring with 102 turns attached to a polished steel stud screwed to the back plate.
Means of Regulation: An index (now missing) on the balance cock registered against an applied silver scale screwed to the back plate, the back-plate inscribed 'Fast' and 'Slow' at the ends of the scale.
Train Counts and Beat Rate:
Great wheel 60 (fusee)
Centre wheel 64 pinion 10
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 14
hour wheel 42
Winding System: Key wound.
Movement: diameter 38.2 mm, height 12.0 mm, pillar height 3.3 mm.
Provenance: Formerly in the Ilbert Collection. Ilbert purchased this from Malcolm Gardner 15/11/1931.
The number of this watch, 6783, seems to be anomalous. The serial numbers for watches signed Arnold & Dent are 3956 - 5463, see Mercer, Dent, pp. 676. The absence of maintaining power is also surprising. Nevertheless this appears to be a genuine movement, perhaps left over as old unfinished stock, numbered and sold after the partnership was dissolved by Dent in 1840, without the name on the watch being altered.
- Not on display
Latest: 3 (2017)
- 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.0914 (Ilbert Collection)
Previous owner/ex-collection number: L134 (Ilbert Ledger)