- Museum number
POCKET-CHRONOMETER MOVEMENT WITH SPRING DETENT ESCAPEMENT AND GOLD ESCAPE WHEEL.
Gold escape wheel.
- Production date
Diameter: 42.30 millimetres (back-plate)
Diameter: 48.80 millimetres (dial)
Thickness: 17.60 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Charles Haley, c. 1810
Signature: On the barrel bridge: 'Chas Haley London P '.(1)
Dial and hands: Enamel dial with curved edge retained by three feet passing through both the dial plate and the front plate, and with pins on the inside of the front plate.
Gold minute and hour hands. The seconds hand steel, not original.
Ebauche marks: 20, 12.
Dial diam. 48.8 mm; dial plate and front plate diam. 47.1 mm; back plate diam. 42.7 mm; frame h. 7.8 mm.
Frame: Full plate with four turned pillars, the back plate retained by pins, detachable barrel bridge. The dial plate with curved edge fixed to the front plate by three screws accessible from under the dial, it serves only as a distance piece between the dial and the front plate. The movement hinge, case catch and spring are attached to the front plate under the dial. All the brass parts are gilded. The front plate cracked from the edge to the maintaining detent pivot hole.
Fusee: Keywind fusee with normal stop-work and maintaining power, the maintaining ratchet wheel steel. The barrel arbor squared at both ends, the setting-up-work mounted on the front plate under the dial. A dust cup fitted in the winding square.
Going train: Arranged in the usual way, the wheels gilded, the pinions nicely finished and polished.
Jewelling: Only the pivots of the escapement arbors in pierced jewels with endstones. The endstone on the balance cock a ruby set in a polished steel ring.
Escapement: Earnshaw type of detent escapement, the escape wheel of a coppery colour.
The polished steel impulse roller not jewelled, with the impulse face leaning towards a radial from the roller centre to the tip. The steel discharge roller jewelled in the usual way. The dovetailed detent left in the grey, fitted with a gold passing spring riveted on, and a thin flat locking stone of pale ruby colour. The detent foot screwed to a block on the underside of the back plate, the banking screw also fitted to an extension of this block. The usual screw let into the block to limit the movement of the detent towards the balance is lacking and is replaced by eccentric peg on the end acting on the front end of the foot. Each time the detent is disturbed it must be carefully repositioned.
Balance: Bimetallic two-armed balance with brass segment weights each held by a polished steel screw from the top. The underside of each rim reduced in height, from the middle towards the free end, over which distance the segment weights can be moved. Diam. of rim 17.8 mm, h. 2.55 mm.
Balance spring: Blued steel helical spring of 4½ turns, with terminal curves. The brass stud secured in a slot on the balance cock by a single screw. Steel collet on the balance staff.
Balance cock: The upper surfaces decorated with engraving; acanthus leaf and fierce mask motifs. A six-sided hole pierced near the balance bearings to give a view of the balance spring beneath.
Great wheel (fusee) 60 teeth
Centre pinion 12 leaves, wheel 64 teeth, no crossings
Third pinion 8 leaves, wheel 60 teeth, 6 arms
Fourth pinion 8 leaves, wheel 70 teeth, 6 arms
Escape pinion 7 leaves, wheel 15 teeth, 4 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 in 1932.
1. Charles Haley, 7 Wigmore Street was made a Freeman of the Clockmakers Company in 1781 and died in 1825. He was a pioneer chronometer maker and was granted a patent, No. 2132, in 1796 for a constant force escapement. A watch fitted with this device is preserved in the Guildhall Museum, London. He was appointed by the Select Committee of the House of Commons to report on Mudge's timekeepers and application for a reward.
- Not on display
Latest: 3 (2017)
3 (Oct 1995) Dial badly damaged at VI
- 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.1603 (Ilbert Collection)
Previous owner/ex-collection number: M11 (Ilbert Ledger)