- Museum number
POCKET-CHRONOMETER MOVEMENT WITH SPRING DETENT ESCAPEMENT.
Spring detent escapement; resilient stud.
Diameter: 42.50 millimetres (back-plate)
Diameter: 47 millimetres (dial)
Thickness: 16.80 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Robert and Henry Molyneux, 1835-1842
Signature: On the back plate and barrel bridge, and on the dial 'R & H Molyneux 30 Southampton Row London N° 3004' (see also W. E. Cribb registration no. 1958,1201.1727).
Dial and hands: Flat enamel dial with subsidiary seconds, attached to the dial plate by three feet and pins. The hands missing.
Ebauche marks ?0 x 9, 3004. Most of the brass parts of the frame also marked 3004.
Dial plate diam. 47.4 mm; front plate diam. 45.8 mm; back plate diam. 42.8 mm; frame h. 7.3 mm.
Frame: Typical full plate construction with detachable barrel bridge, four turned pillars, the back plate retained by pins. The dial plate attached to the front plate by three feet and pins, and having once carried the movement hinge, now removed. The case catch and spring fitted on the dial side of the front plate. All the brass parts gilded, both these and the steel parts badly deteriorated as a result of exposure to the elements.
Fusee: Keywind fusee with the usual stop-work and maintaining power with a steel maintaining ratchet wheel. The setting-up-work fitted in a shallow recess on the dial side of the front plate, the barrel arbor with an extended square on both ends, the barrel flanged on the cover end.
Going train: The usual layout and construction, the brass wheels gilded, the steel pinions and arbors once well finished and polished, now rusted.
Jewelling: The fourth arbor lower pivot in a pierced jewel, those of the escape pinion arbor and balance staff in pierced jewels with endstones. A diamond endstone in a very rusty steel setting on the balance cock.
Escapement: Earnshaw type of spring detent escapement, the gilded brass escape wheel with the arms sunk below the level of the rim and teeth. The polished steel impulse roller with the impulse plane leaning towards a radial to the end furthest from the balance centre (see Stephenson and Farrow, registration no. 1958,1201.1751, for a similar example). The polished steel discharge roller jewelled in the usual way, and without an adjusting flat. Only the very rusty foot of the detent remaining screwed to the underside of the back plate.
Balance: Bimetallic two-armed balance with eight equally spaced brass screws. The steel parts of the rims were originally blued but are now rusty. Diam. of rim 18.0 mm, h. 2.35 mm.
Balance spring: Spiral steel spring of about 5½ turns without an overcoil or terminal curve, but pinned to a once polished steel resilient stud, and a round brass collet.
Great wheel (fusee) 60 teeth
Centre pinion 12 leaves, wheel 80 teeth, no crossings
Third pinion 10 leaves, wheel 75 teeth, 6 arms
Fourth pinion 10 leaves, wheel 80 teeth, 6 arms
Escape pinion 8 leaves, wheel 15 teeth, 3 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, minute pinion 10 leaves
Hour wheel 40 teeth, minute wheel 36 teeth.
Provenance: Ilbert Collection, purchased by Ilbert from Jauncey in 1931.
- Not on display
Latest: 5 (2017) verdigris on brass edge, rust on steel parts Hour, minute and seconds hands missing.
5 (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.1608 (Ilbert Collection)
Previous owner/ex-collection number: H59 (Ilbert Ledger)