- Museum number
SILVER-CASED SUBSIDIARY SECONDS POCKET-CHRONOMETER WITH SPRING DETENT ESCAPEMENT.
Spring detent escapement, missing, Earnshaw type.
Silver case, hallmark.
- Production date
- 1863 (case)
Diameter: 55.70 millimetres (case)
Diameter: 49.40 millimetres (dial)
Thickness: 22.60 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by W. E. Cribb, 1857
Signature: 'W. E. Cribb, 30, Southampton Row Russell Sqe LONDON 3726'. (succeeded R. and H. Molyneux, see registration no. 1958,1201.1608). On dial W. E. CRIBB LONDON 3726.(1)
Case: Plain open face silver case with the London hallmark for 1857 and the maker's mark AT over L 3726. Pendant with TC in cameo and London mark for 1857. The bezel and back hinged to the middle, the dome fixed, no case springs. Diam. 55.7 mm, h. 22.6 mm.
Dial and hands: Flat enamel dial with red 12 fired into back of dial and sunk subsidiary seconds dial at 6 o'clock, fixed directly to the front plate by three feet and pins.
Blued steel hands. Minute and seconds hands probably not original.
Ebauche marks 22, 10.
Front plate diam. 49.0 mm; front plate h. 2.8 mm; back plate diam. 44.7 mm; frame h. 9.0 mm.
Frame: Full plate with four turned pillars,(2) the back plate held by blued steel screws. Detachable barrel bridge. No dial plate or dust cover. The front plate sunk out under the dial, and carrying the hinge and the case catch and spring.
Fusee: Keywind fusee with the usual stop-work and maintaining power, the maintaining ratchet wheel steel. The fine blued steel setting-up pawl and ratchet mounted on the barrel bridge.
Going train: The usual layout and construction, the brass wheels gilded, the pinions and arbors well finished and polished.
Jewelling: The lower pivot of the fourth arbor in a pierced jewel. The pivots of the escapement in pierced jewels with endstones, in the balance cock a diamond endstone, set in a blued steel ring.
Escapement: Earnshaw type of detent escapement, the teeth of the brass escape wheel with a very pronounced undercut. The steel impulse roller not jewelled, only the edge and radial impulse face polished. Usual jewelled discharge roller. The detent broken, only the solid foot remaining screwed to the underside of the back plate beside the gilded brass banking piece and screw.
Balance: Bimetallic two-armed balance with gold compensation and quarter screws. Diam. of rim 18.2mm, h. 1.77 mm.
Balance spring: Blued steel helical spring, 7 complete turns and with terminal curves pinned to a brass collet and a polished steel stud on the balance cock.
Balance cock: Plain, the foot not reaching to the edge of the back plate, the overhung portion particularly thick (1.6 mm).
Great wheel (fusee) 84 teeth
Centre pinion 12 leaves, wheel 80 teeth, 5 arms
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, 5 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, minute pinion 14 leaves
Hour wheel 42 teeth, minute wheel 48 teeth.
Provenance: Ilbert Collection, purchased by Ilbert from Ash in 1932.
(1) William Cribb, 58 Theobalds Road, 1816-22, 17 Southampton Row, 1829; a chronometer maker who succeeded Birchell and Appleton, formerly Molyneux, died 1876 (see Britten's 'Old Clocks and Watches and their Makers', 6th edn, London, 1932).
(2) This watch is unusually late for full plate construction; note that the dial is fixed as in three-quarter plate work.
- Not on display
Latest: 4 (2017) monitor for weeping, otherwise ok 4 (Oct 1995) Detent missing, only foot remains in situ.
4 (Oct 1995) Detent missing, only foot remains in situ.
- 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.1727 (Ilbert Collection)
Previous owner/ex-collection number: M120 (Ilbert Ledger)