- Museum number
Full-plate; fusee; Harrison's maintaining power.
Earnshaw spring-detent escapement; Earnshaw type compensation balance.
White enamel dial, signed.
Gold hour and minute hands, the minute hand a replacement, blued-steel seconds hand.
Gold case, engine-turned; London hallmark for 1822, maker's mark WM.
Case possibly a replacement, see curator's comment.
- Production date
Diameter: 52.90 millimetres (case)
Diameter: 46.80 millimetres (dial)
Thickness: 22.10 millimetres
- Curator's comments
Number 5368 hallmarked London 1810 [Sotheby's New York 17/6/85 lot 371]
Number 5445 hallmarked London 1812 [Sotheby's 28/10/63 lot 100]
Number 5501 hallmarked London 1811 [Sotheby's 27/11/80 lot 156]
Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Barwise and Sons, 1822
Signature: 'Barwise St. Martins Lane LONDON 5414'.
Case: 18-carat gold consular case open face with the London hallmark for 1822 and maker's marks W.M. and M. elsewhere. The dome fixed, the middle and back engine-turned. The fluted pendant somewhat resembles a Thomas Prest keyless, but is solid and with a push-piece to operate the lock spring and open the back. Pendant and bow marked 18. One of the two fly springs broken. Diam. 53.2 mm, h. 22.0 mm.
Dial and hands: Flat enamel dial with bold Roman hour numerals and sunk subsidiary seconds at 6 o'clock, signed in the upper half, 'BARWISE ST. MARTINS LANE LONDON. 5414'.
Gold minute and hour hands, the minute hand a replacement, steel seconds hand.
Ebauche marks: 20, 10
Dial plate diam. 47.5 mm; front plate diam. 44.6mm; back plate diam. 41.8 mm; frame h. 7.3 mm.
Frame: Full plate with four turned pillars, the back plate secured by blued steel screws and brass washers. Detachable barrel bridge. The movement hinge carried on the dial plate, the case catch and spring on the front plate under the dial. Possibly once had a dust cover, only the screw holes for the retaining pillars remain. The dust pipe also removed.
Fusee: Keywind fusee, with stop-work, and maintaining power with a steel ratchet wheel. The return spring for the maintaining detent a short piece of wire set in a screw in the back plate. The setting-up-work on the barrel bridge, the setting-up ratchet wheel with fine teeth, the click controlled by a spring. Another square at the opposite end of the barrel arbor to assist in setting up or for an alternative position for the setting-up ratchet.
Going train: Usual construction, the brass wheels gilded.
Jewelling: The pivots of the third and fourth arbors in pierced jewels, those of the escapement in pierced jewels with endstones. The endstone in the balance cock is a ruby. The discharge roller jewelled.
Escapement: Earnshaw type of detent escapement, the brass escape wheel with 3 arms, not gilded. The dovetailed detent missing, its gilded brass support block with blued steel banking, adjusting and fixing screws. Polished steel impulse roller, the edge, the unusually small notch and the bottom polished. The impulse face on a radial from the centre.
Balance: Bimetallic two-armed balance of Earnshaw type with segment brass compensation weights secured by radial screws on the inside. The steel parts of the bimetallic rims blued. Steel timing screws set in the rims next to the ends of the crossbar. Diam. of rim 16.8 mm, h. 1.65 mm.
Balance spring: Blued steel helical spring, of 5½ turns and with terminal curves, free sprung to an adjustable overhanging stud fixed to the back plate at the end of the barrel bridge.
Balance cock: Engraved acanthus motif decoration on the upper surfaces.
Great wheel (fusee) 60 teeth
Centre pinion 12 leaves, wheel 64 teeth, no crossings
Third pinion 8 leaves, wheel 60 teeth, 5 arms
Fourth pinion 8 leaves, wheel 70 teeth, 5 arms
Escape pinion 7 leaves, wheel 15 teeth, 3 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, minute pinion 16 leaves
Hour wheel 48 teeth, minute wheel 48 teeth
The minute and hour wheels gilded, the minute pinion polished steel.
Provenance: Ilbert Collection; purchased by Ilbert in 1930.
- Not on display
- Latest: 3 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1847 (Ilbert Collection)
Previous owner/ex-collection number: F109 (Ilbert Ledger)