- Museum number
- 1961,0702.1
- Description
-
Chronometer movement with detached verge escapement; Quarter repeating movement in glazed brass box, not original; curved enamel dial, subsidiary seconds; blued steel moon hands.
- Production date
- 1813
- Dimensions
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Diameter: 65.20 millimetres (box)
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Diameter: 55 millimetres (dial and glazed aperture on back of box)
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Thickness: 24.80 millimetres
- $Inscriptions
-
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- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by A. L. Breguet, c. 1813
Movement with Detached Verge Escapement
Signature: Secret signature on the enamel dial below XII twice (as one is indistinct) 'Breguet' and 'No. 971'. The number 971 is also stamped on the front plate under the dial, under the third and fourth cock. Signed at the bottom of the dial 'BREGUET'.(1)
Case: The movement contained in a glazed brass box, the original case would probably have been similar to that of registration no. 1958,1201.1189.
Dial and hands: Curved enamel dial held in a recess in the front plate by a single screw above the 6. The subsidiary seconds dial recessed in the enamel of the main dial and not positioned symmetrically but at the 4. The central hole and the retaining screw hole with turned rings. The seconds' marks were painted on and more than half are missing. The back of the dial signed 'Borel 63'. Blued steel hands, moon type.
Movement:
Front plate diam. 58.8 mm; front plate th. 4.1 mm; overall frame h. 12.0 mm.
Frame: Open Lepine construction built up on the recessed front plate. The brass parts gilded, the steel screws blued. The movement was retained in its case by two dog screws and a peg at the pendant. The escapement mounted on a separate sub frame.
Going train: Lodged between cocks on both sides of the front plate. The wheels not gilded. Breguet stop-work on the going train barrel allowing for turns of wind.
Jewelling: The pivots of the centre, third and fourth arbors of the going train in pierced jewels, those of the escapement similar and with endstones. The steel endstone plates for the pivots of the pallet and fork arbor not jewelled. Resilient jewelling for the balance staff pivots.
Escapement: A verge escapement made detached by the addition of an extra escape wheel working with a pair of pallets for locking, and a fork and roller for unlocking.
On the balance staff are two rollers with inset pieces of jewel to receive impulse at each alternate swing of the balance from a five-toothed escape wheel. Behind this escape wheel, on the arbor of the escape pinion, is mounted a small five-toothed wheel. This wheel is alternatively locked on one or other of a pair of pallets whose frame is mounted on the same arbor as a fork with dart. On the balance staff, below the lower impulse roller, is mounted another double roller with what appears to be an impulse pin on the larger and a passing hollow on the lower roller. This fork and roller system is similar to that to be found in any modern club-toothed lever escapement. However, in this instance no impulse is transmitted through the fork and roller, they merely provide the means for locking and unlocking the smaller escape wheel via the pallet system, and providing safety action to prevent unlocking of the "escapement during the supplementary arc of the balance.
Balance: Bimetallic three-armed balance silver-brass and steel with gold timing and compensation screws, and brass screws for poising. Only one screw at the end of each rim and a series of 9 dots whose purpose is obscure. Diam. 21.2 mm, h. 2.2 mm.
Balance spring: Blued steel spiral spring with Breguet overcoil and terminal curve, free sprung to a most unusual design of stud under a steel plate held with two screws, on the centre line of the balance cock. The part of the stud beneath the steel plate is spherical and sits in a V-groove in the cock. The stud can thus align itself in all planes except that which affects the height of the spring. Such an arrangement is very rare.
Repeating work: Typical Breguet quarter repeating with a single hammer working ' dumb ', and with jump hour mechanism (see registration no. 1958,1201.1189). The repeating mainspring visible through a hole in the cock that supports its arbor, there being no cover on the barrel. The speed of striking of the repeating train is controlled by a recoil escapement which has the travel of its pallets limited by an adjustable flexible stop.
Going train counts:
Great wheel (barrel) 90 teeth
Centre pinion 10 leaves, wheel 80 teeth, 5 arms
Third pinion 10 leaves, wheel 60 teeth, 5 arms
Fourth pinion 8 leaves, wheel 50 teeth, 4 arms (contrate)
Escape pinion 8 leaves, 2 wheels, 5 teeth each
Beats per hour: 18,000
Motion work:
Hour and minute wheels 14 teeth
Repeating work: First wheel 60 teeth Second wheel 46 teeth Third wheel 36 teeth Escape wheel 16 teeth Three pinions of 8 leaves each.
Provenance: Purchased: 1961.
Note:
(1) According to the records of the Maison Breguet in Paris, this watch was sold twice to M. Mainet, as No. 971 in 1813 and as No. 1802 in 1818. Later it was sold as No. 3366 to M. Fatton for J. Whelley in 1825 for 3,600 francs. The escapement was made by Le Roy.
Bibliography: E. Bornschein, 'Ein original Breguet-Uhrwerk', Schriften der Freunde alte Uhren, III, pp. 65, 66; Daniels 1975, pp. 314-317.
- Location
- Not on display
- Condition
- Latest: 2 (2017) 2010. Case washed in DTPA followed by Goddards and then lacquered using Frigelene. PAB
- Acquisition date
- 1961
- Department
- Britain, Europe and Prehistory
- Registration number
- 1961,0702.1
