- Museum number
GOLD PAIR-CASED SUBSIDIARY SECONDS POCKET-CHRONOMETER WITH SPRING DETENT ESCAPEMENT.
Spring detent escapement.
Gold pair cases.
- Production date
- 1818 (case)
Diameter: 52.50 millimetres (dial)
Diameter: 55.90 millimetres (inner case)
Diameter: 60.80 millimetres (outer case)
Thickness: 27.50 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Perigal and Brown, 1818
Signature: On the back plate 'Perigal and Brown Coventry Street London No 3020'.
Case: 18-carat gold pair cases with the London hallmark for 1818 and the marker's mark: a sunburst with central face in a cartouche similar to that for the hallmark. Outer case diam. 61.5 mm; inner case diam. 56.1 mm, h. over glass 26.1 mm.
Dial and hands: Flat enamel dial; the minute and second markings appear to be engine divided with a scriber on turned rings before the application of the black enamel. The dial secured to the dial plate by three short feet and pins. Flat, red-gold hands.
Dial plate diam. 53.0mm; front plate diam. 50.6mm; back plate diam. 50.3 mm; frame h. 8.0 mm; front plate th. 1.45 mm; back plate th. 1.10 mm.
Frame: Full plate construction with four turned pillars, the back plate retained by pins. The dial plate carrying the movement hinge secured to the front plate by four short feet and pins. The case catch and spring on the front plate under the dial. No dust cover or any provision for one. All the brass parts nicely gilded.
Fusee: Keywind fusee with the usual stop-work and maintaining power, with brass maintaining ratchet wheel. Blued steel setting-up-work on the front plate under the dial, the barrel arbor with an extended square on that end only. The barrel with a very small narrow flange on the cover end.
Going train: The upper end of the centre pinion polished integral with the arbor. The brass wheels gilded, the pinions and arbors well finished and polished.
Jewelling: All the pivots of the going train arbors, including the fusee, in fine large pierced jewels with screwed settings. The escapement pivots in pierced jewels with endstones. A large diamond in a blued steel setting on the balance cock.
Escapement: Arnold spring detent escapement. The escape wheel of a pale coppery colour, with arms and rim sunk below the level of the teeth. The leading edges of the teeth almost straight, not cycloidal, and marked. A solid blue-white sapphire impulse roller with a deep notch. The impulse face a radial and with a slightly rounded corner. The jewelled steel discharge roller with a flat for adjusting. The well-made detent with polished top to the foot, gold passing spring held by a single rivet, and the locking stone made from a flat piece of jewel set in a slot in the detent. Banking provided against a screw in a slot in the backplate in a similar way to that usually used by the Arnolds.
Balance: Bimetallic two-armed balance, the rims integral with the arms. Steel pieces screwed to the free ends carrying brass compensation nuts on threaded rods. Steel timing screws at the ends of the arms. Small gold screws set in the rim near their fixed ends. An unfilled hole in one balance arm midway from the centre. The balance riveted to a brass collet on the staff.
Balance spring: Blued steel helical spring of 4½ turns, with terminal curves, free sprung to an overhanging adjustable stud screwed to the back plate. A brass bar-shaped collet. Diam. 22.0 mm, h. 1.92 mm.
Balance cock: Pierced and engraved decoration unusual in a watch of this date. A small brass peg points downwards from a hole in the edge of the table on the side nearest the winding square.
Great wheel (fusee) 62 teeth
Centre pinion 12 leaves, wheel 75 teeth, no crossings
Third pinion 10 leaves, wheel 64 teeth, 5 arms
Fourth pinion 8 leaves, wheel 70 teeth, 5 arms
Escape pinion 7 leaves, wheel 15 teeth, 4 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 Webster in 1931.
- Not on display
Latest: 3 (2017)
4 (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.1737 (Ilbert Collection)
Previous owner/ex-collection number: H61 (Ilbert Ledger)