- Museum number
MOVEMENT AND DIAL OF A LEVER WATCH WITH DATE INDICATOR.
3/4-plate, fusee, Harrison's maintaining-power.
Ratchet-tooth lever-escapement, Earnshaw compensation balance, Breguet over-coil.
White enamel dial; hours I-XII; subsidiary date-dial at XII, subsidiary seconds dial at VI.
Gold spade hands, blued steel seconds and calendar hands, seconds hand has gold collet.
- Production date
Diameter: 39.50 millimetres (back-plate)
Diameter: 44.20 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 V (Unpublished manuscript)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 James McCabe
London, c. 1880
Movement of a ratchet tooth lever watch with date indicator.
Signature: On the dial 'James M'Cabe Royal Exchange LONDON No 12981 Made to the Order of D Johnson CALCUTTA' and on the back plate 'James McCabe Royal Exchange LONDON 12981'.
Case: Missing, the movement was held in the case by a locating pin and two dog screws.
Dial & Hands: Flat dial with a subsidiary date dial below XII and a subsidiary seconds dial above VI. Gold spade hour and minute hands, blued-steel date and seconds hands, the latter with a gold boss.
Dial-plate: None intended.
Dust-cap: None intended.
Ebauche Marks: IMC 12981 16 X 6.(1)
Frame: 3/4 plate layout, the back plate supported by four turned pillars and secured by screws. There is a separate plain brass bush recessed into the back plate for the rear fusee pivot. Punched IMC 12981 on the underside of the balance cock foot and on the inside of the back plate. A combined cock for the escape wheel and pallets. The pallet and escape wheel front bearings are in a sub plate on the dial side of the front plate. The balance bearing however is mounted directly in the front plate with a viewing hole in the sub plate so that the oil in the bearing can be examined.
Fusee, Barrel and Mainspring:
Fusee: six-turn fusee with Harrison's maintaining power, the maintaining ratchet wheel of steel. The fusee has sliding bar stop-work (see Ill).
Barrel: internal diameter 16.6 mm, height 3.7 mm.
Mainspring: height 3.3 mm, thickness 0.23 mm.
Barrel Arbor: diameter 5.15 mm, not snailed.
Train: A high quality train with all the wheels gilded, the centre, third and fourth wheels with six crossings.
Jewelling: Jewelled bearings for the fourth wheel pivot in the front plate and for the whole of the escapement, which has ruby endstones throughout except for that in the balance cock which is a diamond. All the jewels are in screwed settings.
Escapement: An acute-angle layout ratchet tooth lever escapement with short lever, single roller and D-shaped impulse pin.
The enclosed pallet stones have convex impulse and locking faces. The polished brass escape wheel has three crossings.
An equal impulse escapement.
No. of teeth embraced 32.
Balance & Spring: A split bimetallic balance with gold compensation and quarter screws; diameter 17.0 mm, thickness 1.5 mm. Blued-steel flat spiral spring with 14 turns and a 100% terminal curve. Attached to a rectangular steel collet on the balance staff and a polished steel stud on the balance cock.
Means of Regulation: An index on the balance cock registers against a divided scale with 'Fast' and 'Slow' engraved on the balance cock.
Train counts and Beat rate:
Great wheel 60 (fusee)
Centre wheel 64 pinion 12.
Third wheel 60 pinion 8
Fourth wheel 80 pinion 8
Escape wheel 15 pinion 8
Beat rate: 18,000
Motion Work: cannon pinion 12
minute wheel 36, minute pinion 10,
hour wheel 40
The centre arbor pivot that carries the cannon pinion is broken and still within the cannon pinion.
Date Work: A ratchet toothed date wheel has 31 teeth and is indexed by a pin on an 80 toothed wheel which is in mesh with the hour wheel.
Winding System: Key wound.
Movement: diameter 44.2 mm, height 12.5 mm, pillar height 4.4 mm.
Provenance: Formerly in the Ilbert Collection. Ilbert purchased this from Collet in June 1939.
(1) This does not conform in date with that shown in the chart by Hackamack. Sometimes there are rogue watches that do not conform to an otherwise readily ascertained relationship between the number and its apparent date. Extra care is obviously required in checking whether or not such exceptions are genuine but in the case of this movement there is little doubt that it is a good example from the McCabe workshops.
According to P. E. Hackamack in "James McCabe" AH Vol. X (Summer 1977) pp. 312-316, all McCabe's highest quality watches with serial numbers greater than 8000 are stamped "IMC" on the front plate. From about 1830 the punched marks on the front plate are repeated on the inside of the back plate, and from about 1838, the highest quality McCabe watches are punched SS in addition to the marks on the case, the front plate and the inside of the back plate.
- 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.1060 (Ilbert Collection)
Previous owner/ex-collection number: Q57 (Ilbert Ledger)