- Museum number
SUBSIDIARY SECONDS POCKET-CHRONOMETER MOVEMENT WITH SPRING DETENT ESCAPEMENT.
Spring detent escapement; eccentric adjustment for detent.
- Production date
Diameter: 44.90 millimetres (back-plate)
Diameter: 48.70 millimetres (dial)
Thickness: 18 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by J. Reid, c. 1810
Signature: On the back plate 'Ball Alley Lombard Street', in the upper half of the dial 'REID CHRONOMETER'.(1)
Dial and hands: Flat enamel dial secured to the dial plate by three feet and pins, 7 fired into the back.
Gold minute and hour hands, blued steel seconds hand.
Ebauche marks 22, 7, 8. The number 7 also punched on the underside of the back plate and on the balance potence.
Dial plate diam. 48.8 mm; front plate diam. 45.5 mm; back plate diam. 45.0 mm; frame h. 6.9 mm.
Frame: Full plate construction with detachable barrel bridge, four turned pillars, the back plate retained by blued steel screws. The dial plate secured by three feet and pins, and carrying the movement hinge. The case catch and spring on the front plate under the dial. All the brass parts gilded.
Fusee: Keywind fusee with the usual stop-work and maintaining power, the maintaining ratchet wheel steel. The setting-up-work on the barrel bridge, the barrel arbor with an extended square on that end only. The barrel with a flange on the cover end.
Going train: Typical construction, the brass wheels gilded, the steel pinions and arbors well finished and polished.
Jewelling: The pivots of the third, fourth and escapement arbors in pierced jewels, those of the escapement with endstones.
Escapement: A development of Earnshaw's spring detent escapement. The brass escape wheel with arms and rim sunk out below the level of the teeth. The steel impulse roller polished on the bottom and radial impulse face only. The jewelled steel discharge roller without an adjusting flat, and fitted between the impulse roller and the brass collet on which the balance is mounted. The detent somewhat resembling that for an Arnold escapement and fitted in a slot in the back plate. The locking stone made from a flat piece of ruby, the gold passing spring held by a single rivet. The detent foot steady pin in a hole in a round steel plate, with a screwdriver slot. This plate when turned moves the detent towards or away from the balance. Banking for the detent provided against another round steel plate set in a recess in the back plate and held by a central screw. Part of this plate is filed away leaving a thin wedge to contact the detent.
Balance: Bimetallic two-armed balance of Earnshaw type with brass segment weights held by brass screws from on top, and brass timing screws set in the rims at the ends of the arms. Diam. of rim 18.2 mm, h. 2.3 mm.
Balance spring: Blued steel helical spring of 6 turns, with terminal curves, free sprung to a polished steel stud on the balance cock, and a brass bar-shaped collet.
Great wheel (fusee) 60 teeth
Centre pinion 12 leaves, wheel 80 teeth, no crossings
Third pinion 10 leaves, wheel 75 teeth, 5 arms
Fourth pinion 10 leaves, wheel 80 teeth, 5 arms
Escape pinion 8 leaves, wheel 15 teeth, 3 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, brass minute pinion 14 leaves
Hour wheel 42 teeth, minute wheel 48 teeth.
The brass wheels and minute pinion gilded.
Provenance: Ilbert collection; purchased by Ilbert from Malcolm Gardner in 1931.
(1) Britten 1982 records a J. Reid at the address shown on the back plate between 1800 and 1816. Baillie 1951 gives him as James Reid 1789-1824 and mentions this watch.
- Not on display
Latest: 3 (2017)
4 (Oct 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.1747 (Ilbert Collection)
Previous owner/ex-collection number: L91 (Ilbert Ledger)