independent centre-seconds watch;
- Museum number
SILVER CASED LEVER WATCH WITH INDEPENDENT CENTRE-SECONDS AND STOP-LEVER.
Hanging barrels; separate plate for train wheels.
Lever escapement; Savage-type impulse jewel.
Gold three-arm balance; split bi-metallic compensation curb.
Engine-turned silver case.
- Production date
Diameter: 59.20 millimetres (case)
Diameter: 54.30 millimetres (dial)
Thickness: 20.20 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by Henri Lepaute
Paris, c. 1860
Silver cased, independent centre-seconds stop-watch with club tooth lever escapement and a wide impulse jewel.
Signature: On the cuvette 'H Lepaute Paris' and also 'ECHAPPEMT A ANCRE SIX TROUS EN PIERRE'.
Case: Open face silver case with an engine-turned back and reeded band. Inside the back are the French quality mark for 0.800 silver used after 1838 and the casemaker's lozenge shaped mark containing the letters A and D with a key? between.(1) Scratched 377-3 on the outer snap edge. A slide in the case band operates the stop mechanism. The hole in the silver pendant has been filled at a later date to accommodate a replacement bow. The hinged cuvette with a milled edge is gilded and has two winding holes with arrows indicating direction of wind and also a central hand set hole. It is scratched LB 597 on the inside.
Dial and Hands: Slightly domed dial with a seconds circle around the minute circle marked at each second and numbered 15, 30 and 45, and 60. On the back of the dial is an indistinct inscription `Noire'? Fine blued-steel moon pattern hour and minute hands and a finely tapered blued-steel centre-seconds hand with a counter-balanced tail.
Dial-Plate: A plate with a rear diameter to enclose the movement front plate and a high rim secured to the front plate by four screws to provide a recess for the independent centre-seconds work.
Ebauche Marks: None
Frame: On the dial side of the front plate, various cocks provide bearings for the wheels of both trains and there are two larger drum-shaped bridges which provide front bearings for the two barrel arbors and also act as retaining covers for the winding ratchets. On the rear of the front plate the trains are mainly under the small shaped back plate secured by two screws. There are also two separate cocks for the escape wheel and the lever, the latter has been thinned, broken and soft soldered together. The balance cock is undecorated.
Going Barrel and Mainspring:
Barrel a standing going barrel with a recessed cover and with five-turn Geneva stop work.
Internal diameter 20.0 mm, height 3.0 mm.
Mainspring: height 2.70 mm, thickness 0.27 mm.
Barrel Arbor: diameter 7.0 mm, not snailed. There is a brass head on the arbor
Going Train: A high quality train with polished brass wheels, the centre wheel with five crossings the others with four.
Jewelling: Jewelled bearings for the escapement except for the front escape wheel pivot. The jewels are rubbed in except for those in the balance cock which are in a screwed setting. There is a ruby endstone for the front balance pivot and a diamond endstone in the balance cock.
Escapement: A right-angle layout club-tooth lever escapement with a very short lever. The double roller consists of a polished steel impulse roller with a horizontal steel impulse pallet into which is inserted a slip of jewel, and a slightly smaller gold safety roller. The pallets are of an unusual design. The very long enclosed pallet stones are convex on both locking and impulse faces. The entrance pallet is also convex along its length. The pallet frame has two upright steel pins to work with the impulse pallet jewel. The steel escape wheel, with four crossings, is polished all over and there are oil retaining slots in the tooth tips which are also slightly convex.
An equal impulse escapement.
No of teeth embraced 32.
Balance & Spring: A rounded-rim, three-armed gold balance, diameter 20.0 mm, thickness 0.7 mm. A blued-steel flat spiral spring of six turns, pinned to a brass stud on the balance cock table.
Means of Regulation: An index on the balance cock registers against three marks punched on the balance cock table, the centrally disposed mark larger and above the other two. The engraved letters 'A' and 'R' flank the punched marks.
Temperature Compensation: Riveted to the end of the regulator index is a Breguet-type bimetallic compensation curb with a single curb pin at its free end. The compensation curb has been repaired at the base using soft solder.
Train Counts and Beat Rate:
Great Wheel 76 (barrel)
Second wheel 64 pinion 10
Third wheel 60 pinion 8
Fourth wheel 60 pinion 8
Escape wheel 15 pinion 6 (carries a contrate disc with 3 escape slots)
Beat Rate 18,000
Great wheel 54 (barrel)
Second wheel 24 pinion 6
Third wheel 24 pinion 6
Fourth wheel 24 pinion 6
Fifth wheel 24 pinion 6
Idle wheel 30 (carries the independent seconds hand)
Sixth wheel 32 pinion 12
Fly Pinion 8 (with 3 arms working with the escape wheel contrate disc)
Independent Train: A six-wheel train driven by a small standing going barrel and terminating with a fly pinion. The first four wheels are solid brass and run on the rear of the front plate. The fifth pinion carries a wheel running on the dial side of the front plate. This fifth wheel drives an idle wheel, which runs on a steel bridge and pipe in the centre, and carries the centre-seconds hand between the hour and minute hands. The fifth and idle wheels are both of polished brass and each has four crossings. A solid brass sixth wheel with a polished steel pinion carries the drive from the idle centre-seconds wheel to a steel 3-arm fly which is locked and unlocked by a contrate disc with three slots mounted on the extended arbor of the escape wheel.
A lever moved by a slide on the case band situated at about 10 o'clock interrupts the fly by catching one of its three arms.
Winding Mechanism: Key wound.
Case: diameter 59.0 mm, height 19.0 mm.
Movement: diameter 55.0 mm, height 16.0 mm, pillar height 2.4 mm.
Provenance: Formerly in the Ilbert collection. Ilbert purchased this from Gelis 4/4/1931.
(1) Possibly the mark of Paul Alexandre Devambez, box maker of 104 Rue St. Honore, Paris, see Arminjon, Beaupuis and Blimoff, Dictionnaire des Poincons de Fabricants d'Ouvrages d'or et d'argent, Paris 1798-1838. 1991, p.55.
Despite the sophistication of the escapement and the inclusion of a compensation curb this must have been a poor timekeeper. The independent train is exceptionally long and inefficient and the flirt arms rest on much too large a diameter on the contrate disc mounted on the escape wheel. The drag on this must vary considerably when the seconds hand is in operation.
- Not on display
- Latest: 3 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1134 (Ilbert Collection)
Previous owner/ex-collection number: H94 (Ilbert Ledger)