- Museum number
SILVER-CASED SUBSIDIARY SECONDS POCKET-CHRONOMETER WITH SPRING DETENT ESCAPEMENT.
Arnold spring-detent escapement.
- Production date
- 1812 (case)
Diameter: 56.90 millimetres (case)
Diameter: 49.90 millimetres (dial)
Thickness: 23.30 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by C. Haley, c. 1800
Signature: On the back plate and barrel bridge 'Haley Wigmore Street, London MNN'. On the dial HALEY LONDON and 6 over MNH.
Case: Case not original. The movement a loose fit in the case badly burred around winding hole, poorly cut out clearance for catch, movement hinge filed to clear case. Silver consular case with London hallmark for 1812 and the maker's mark WB over GH on the inside of both dome and back. Diam. 56.9 mm, h. over the glass 24.0 mm.
Dial and hands: Flat enamel dial with many hair cracks and attached to the dial plate by three feet and pins.
Blued steel spade hands, the second hand fitted onto a gold tube with a cap over the boss of the hand.
Dial plate diam. 50.4 mm; front plate diam. 49.0 mm; back plate diam. 43.0 mm; frame h. 8.8 mm.
Frame: Full plate with four turned pillars, the back plate retained by pins, detachable barrel bridge. The dial plate carrying the movement hinge attached to the front plate by three short feet and pins. The case catch and spring mounted on the front plate under the dial. The front plate cracked from the edge towards the maintaining detent hole. All the brass parts gilded.
Fusee: Keywind fusee with normal stop-work and maintaining power, the maintaining ratchet wheel steel. The setting-up-work under the dial on the front plate, the barrel arbor squared on that end only.
Going train: The usual arrangement, the brass wheels gilded, the steel pinions and arbors polished.
Jewelling: The pivots of the fourth and escapement arbors in pierced jewels, the escapement with endstones. A ruby endstone on the balance cock set in a polished steel ring.
Escapement: Arnold type of detent escapement with brass escape wheel, the impulse surfaces of the teeth unmarked. The steel impulse roller with a jewelled impulse surface made in a similar way to Arnold's but with a radius on the corner on which impulse is received. The steel discharge roller with a jewel, and flat for adjusting.
Balance: Similar to the Arnold 'z' type. Steel crossbar with blocks left standing on the ends. Brass and steel bimetallic rim pieces screwed to the upstanding blocks with two screws each. Steel timing screws passing through clearance holes in the rims into slotted holes in the blocks. Steel quarter screws set in the rims near their free ends. Brass compensation weights on curved threaded rods on the free ends of the rims. The balance mounted on a brass collet on the balance staff.
Balance spring: Blued steel helical spring of 5½ turns, with terminal curves. Polished steel stud on the balance cock with round hole and pin to clamp the end of the upper terminal curve. Brass collet with similar clamping for the lower terminal curve. Diam. of rim 19.6 mm, h. 24.7 mm.
Balance cock: The upper surfaces decorated with flower and acanthus leaf motifs.
Great wheel (fusee) 62 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, 5 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, minute pinion 16 leaves
Hour wheel 48 teeth, minute wheel 48 teeth
Provenance: Ilbert Collection, purchased by Ilbert from Hutchinson, 1935.
- Not on display
Latest: 3 (2017)
4 (Oct 1995) Hairline cracks on dial
- 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.1736 (Ilbert Collection)
Previous owner/ex-collection number: P2 (Ilbert Ledger)