- Museum number
POCKET-CHRONOMETER MOVEMENT WITH ARNOLD'S SPRING DETENT ESCAPEMENT AND WHITE ENAMEL DIAL WITH SUBSIDIARY SECONDS.
Pocket chronometer movement and dial.
Full-plate; separate barrel bridge; fusee; Harrison's maintaining power.
Arnold spring detent escapement; Arnold Z balance; helical blued-steel balance spring.
White enamel dial, hours I-XII, subsidiary seconds. Signed.
- Production date
Diameter: 45 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by John Roger Arnold, c. 1802 (No. 1818 has the hallmark for 1801 and No. 1869 for 1802)
Signature: On the back plate, but partly missing as it is cut by the slot for the detent, 'Jn° R Arnold London Invt. et Fecit No. 1831'.
Dial and hands:
Signature 'ARNOLD 1831' in the upper half. Gold hands.
For similar movements see registration nos 1958,1201.1581 and 1958,1201.1582 On the dial plate scratched 'Arnold 1831' and 'No. 2'.
Dial plate diam. 44.9 mm; front plate diam. 44.1 mm; back plate diam. 40.2 mm; frame h. 7.7 mm.
Frame: Similar to 1958,1201.1581.
Fusee: Similar to 1958,1201.1581.
Going train: Similar to 1958,1201.1581 but the great wheel has 60 teeth instead of 58.
Jewelling: Similar to 1958,1201.1581.
Escapement: Similar to 1958,1201.1581.
Balance: Similar to 1958,1201.1581 but the blocks on the ends of the crossbar finished differently. Diam. 19.8 mm, h. 2.4 mm.
Balance spring: Similar to 1958,1201.1581 but without the shield or amplitude limiting device under the balance cock. 6 complete turns, with terminal curves.
Balance cock: Compare with 1958,1201.1581 and 1958,1201.1582.
Great wheel (fusee) 60
Centre pinion 12 leaves, wheel 64 teeth, no crossings
Third pinion 8 leaves, wheel 60 teeth, 4 arms
Fourth pinion 8 leaves, wheel 80 teeth, 4 arms
Escape pinion 8 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 from Malcolm Gardener in 1936.
- Not on display
Latest: 2 (2017)
3 (Sep 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.1580 (Ilbert Collection)
Previous owner/ex-collection number: P39 (Ilbert Ledger)