- Museum number
Pivoted detent escapement.
- Production date
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Duchemin; c. 1840
Signature: On the cuvette 'E. No. 184 Duchemin A. PARIS'. On the dial 'Duchemin'.(1)
Dial and hands: Flat white enamel dial with flush subsidiary seconds, the feet pass through the front plate and are held with pins.
Blued steel moon hands.
Case: Open face silver case with a glazed back over the cuvette. Three small French hallmarks, a crayfish or lobster (in use 1822-38), a crab on the pendant and crab on the inside of the cuvette. Also the Paris guarantee mark for small work used after 10 May, 1838.
Front plate diam. 52.6mm; movement h. over the barrel 10.9 mm
Frame: Lepine type of construction built up on a single thick plate and recessed under the dial. The brass parts finely frosted and gilded.
Barrel: Hanging going barrel with Breguet type of geared stop-work on the cover allowing four turns of wind.
Going train: A small train in relation to the space available. The brass wheels left polished, the pinions well finished and polished. The third pinion partly turned away to clear the fourth wheel.
Jewelling: The pivots of the balance staff in pierced jewels, with a ruby endstone on the balance cock and a steel end plate for the lower balance staff pivot.
Escapement: A form of pivoted detent escapement with all the safety action on the detent. The escape wheel teeth are normally locked by a steel piece screwed to the tail of the detent. Near the nose of the detent a steel pin intersects the teeth when the escape wheel is unlocked. If the detent unlocks at the wrong moment for any reason this pin causes it to relock before the wheel can advance by more than a tooth space. The normal impulse roller is replaced by an obtuse angled pallet with an impulse plane that leans towards a radial to the tip at an angle of about 40°, the front part of the wheel teeth showing signs of wear. The discharge roller is made from a piece of steel with a protrusion to intersect and unlock the detent. The passing spring has a tiny foot screwed to the underside of the tail of the detent and banking at the nose is against a brass pin.
Balance and spring: Plain gilded brass three-armed balance with various steel screws set in the outer edge; the screws probably not there originally since the case has been relieved at the hinge in a most unworkmanlike manner to clear them. Diam. 21.2 mm, h. 1.2 mm.
Flat spiral steel balance spring of 9½ turns, with a separate overhanging piece for the stud and an index on the balance cock. No thermal compensation. The pins for the index are set in a separate steel piece held by a single screw and a steady pin to the overhanging part of the index. There are holes for pins at a closer radius to the balance staff, and other signs of alteration, so possibly a compensation curb was once fitted.
Great wheel (barrel) 96 teeth
Centre pinion 12 leaves, wheel 64 teeth, 5 arms
Third pinion 8 leaves, wheel 60 teeth, 5 arms
Fourth pinion 8 leaves, wheel 60 teeth, 5 arms
Escape pinion 10 leaves, wheel 10 teeth, 4 arms
Beats per hour: 7,200
Cannon pinion 12 leaves, minute pinion 10 leaves
Hour wheel 40 teeth, minute wheel 36 teeth
The minute and hour wheels gilded.
Provenance: Ilbert Collection; purchased by Ilbert from Malcolm Gardner in 1941.
(1) Duchemin was working at the Quai de l'Horloge in 1820 and in the Place du Chatelet, 1820-40.
- Not on display
- Latest: 4 (2017) traces of rust
- 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.1730 (Ilbert Collection)
Previous owner/ex-collection number: Q82 (Ilbert Ledger)