- Museum number
GOLD AND ENAMEL CASED LEVER EQUATION WATCH WITH HALF QUARTER-REPEAT, CENTRE-SECONDS, SKELETONISED MOVEMENT, CHAIN AND KEY.
Lever escapement; gold scape-wheel; compensation curb; equation work.
Enamel dial; gold chapters.
Gold and enamel case; glazed back.
- Production date
Diameter: 59.40 millimetres (case)
Diameter: 56 millimetres (dial)
Diameter: 49.40 millimetres (glazed aperture on back)
Length: 84.30 millimetres (chain)
Length: 40 millimetres (key)
Thickness: 25.20 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by François-Louis Godon(1)
Gold and enamel cased half-quarter repeating, centre-seconds equation watch with an early club-tooth lever escapement.
Signature: On the dial 'F L Godon: Ro. de Ca. de S.M.C.'(2) and around the dial-plate edge 'F. L. Godon'.
Case: Gold consular case, the band with blue enamel decoration. The case is glazed back and front. Pump pendant for the repeating work. The enamel has been damaged around the hinge area and elsewhere and has subsequently been repaired. Attached to the pendant bow is a chain 80 mm in length with a winding key at its fee end. The steel acting part of the key is connected to a red gold body of chain link design with a swivelling ring. The body of the key has straight sides with semi-circular ends.
Dial and hands: The dial has gold markings and Arabic numerals. Seconds numbered at 15, 30, 45 and 60 with arrows at each of the half-quarters. The enamel is damaged around the winding holes. Concentric with the centre is a scale for the equation of time, calibrated 15R - 0 - 16A. The equation of time is shown by a gold sun hand. Gold Breguet-style hour and minute hands and a gold counterpoised centre-seconds hand. The dial is signed on the back 'Vincent Eleve de Cave'(3)
Dial-plate: Gilt-brass dial-plate in the form of a raised ring with a chamfered inner edge screwed to the movement front plate and with engraved decoration around the outside. The hinge is secured by two screws. The case catch and spring are also attached to this plate.
Dust-cap: None intended.
Ebauche Marks: None
Frame: Full plate construction, the skeletonised back plate with various cocks and bridges. The narrow barrel bridge and the cocks for centre-seconds wheels and the balance are engraved with foliate decoration. A separate cock for the third wheel with a polished steel coqueret. A further cock for the fourth wheel, escape wheel and the lever which operates the centre seconds wheel, these last two also with a polished steel coquerets.
Barrel & Mainspring:
Barrel: gilded going barrel with continental-type stopwork, the finger now missing. The barrel ratchet is secured to the arbor by a long-screw. A long polished steel click. Barrel internal diameter 20.4 mm, height 4.5 mm.
Mainspring: height 3.85 mm, thickness 0.2 mm, with a brace.
Barrel arbor: diameter 6.0 mm, not snailed.
Train: The wheels are not gilded but are polished and each has four crossings. The pinions have slender leaves and well polished undercuts. There are two wheels mounted on the third wheel arbor. The upper third wheel is loose on the arbor and is driven by a thin blued-steel whiplash spring attached to it, which engages in an internally cut ratchet toothed ring fixed to the lower third wheel and drives through pressure on the flank of a tooth not against its radial face. The third wheel proper (lower), fixed to the arbor, drives the fourth wheel pinion. The upper third wheel engages with the centre-seconds pinion. The gold, ratchet-toothed centre-seconds wheel is allowed to move forward each second by the action of a separate lever escapement controlled by a cam with three lifting faces mounted on the escape wheel arbor proper.
Escapement: A straight-line layout club-tooth lever escapement with no draw. The gold escape wheel with four crossings has narrow tips to the teeth. The pallets are not jewelled. The lever has an applied gold notch secured by screws. The safety roller and banking pins are also gold and there is a gold poising piece fitted to the lever.
A mixed escapement.
No of teeth embraced: 32.
Balance & Spring: A rounded-rim, plain gold, three-arm balance, diameter 16.8 mm, thickness 9.5 mm. Flat spiral blued-steel spring of 6 turns pinned to a round split brass collet and a stud on the back plate.
Means of regulation: A Bosley-type regulator, which carries a compensation curb, registers against a divided scale on the back plate which is also engraved with 'R' and 'A'.
Thermal Compensation: A Breguet-type bimetallic compensation curb is screwed to the index. The free end acts as one curb pin with the other curb pin fixed in the index.
Train Counts and Beat Rate
Great wheel 72 (barrel)
Centre wheel 72 pinion 10
Third wheel 64 pinion 8
Fourth wheel 50 pinion 8
Escape wheel 15 pinion 6
Beat Rate: 18,000
Centre seconds train:
Ancillary third wheel 60
Centre seconds wheel 30 pinion 9
Motion work: cannon pinion 12
minute wheel 36, minute pinion 10
hour wheel 40
Great wheel 52
Second wheel 36 pinion 7
Third wheel 34 pinion 7
Fourth wheel 30 pinion 7
Fly pinion 7 (with a slipping inertia weight)
Equation train: On the hour wheel is a steel wheel of 18 which meshes with a wheel of 36. This wheel carries a pin which indexes a 30-point star wheel with a sprung jumper. The star wheel has a pinion of 6 which drives a wheel 73 to which is fixed the 'kidney' cam. A pinion of 12, freely mounted on the centre arbor and carrying the equation hand, is driven by a sprung rack with 12 teeth. A pin on one end the rack tail is kept in contact with the `kidney' cam. Thus the position of the kidney cam determines the position of the equation hand. A ring mounted on the kidney-cam wheel is engraved with abbreviated months and the number of days in each to aid setting.
Winding Mechanism: Key wound, but with no provision for setting the hands(4).
Case: diameter 59.5 mm, thickness 25.2 mm (over glasses).
Movement: diameter 55.5 mm, height 17.7 mm, pillar height 3.7 mm.
Provenance: Formerly in the Ilbert Collection. Purchased by Ilbert from Malcolm Gardner 2/7/49. The watch had previously belonged to Ivor Ferguson and was sold at Sotheby's London on 16/6/1949, lot 94, the catalogue does not mention the fact that the watch indicates the equation of time.
(1) François Louis Godon, Rue de Valois-St. Honoré, Paris, 1787-90. Clockmaker to the Court of Spain 1786-1793. There are many of his clocks in the collection of the Patrimonio Nacional, Madrid, see J. Ramon Colon de Cavajal, Catalogo de Relojes de Patrimoni Nacional Madrid 1987. Godon was also clockmaker to the King of France and worked with Furet See also José Luis Basanta Campos Relojeros de España Diccionario Bio-Bibliografico by S.L. 1972 p. 59.
(2) Reloxero de Camara de Su Majestad Catòlico (Chamber Clock Maker to his Catholic Majesty).
(3) Vincent recorded as dial enameller of Place de Thionville, Paris 1806-1815, who is known to have worked for Louis Berthoud, see Tardy 1971, p. 644. He was a pupil of John Antoine Cavé, a dial enameller of Paris who is recorded as working in 1776, see Tardy, 1971 p.117. There is also a watch in the British Museum Collections (CAI.1082) by Perrin Frères, Neuchâtel, Switzerland, which has a dial scratched 'Cave' in the counter-enamel.
(4) The lack of provision for hand setting is astonishing. Presumably the hands would have to be reset by a watchmaker once the time shown was sufficiently incorrect to be a source of annoyance to the owner.
- Not on display
- Latest: 3 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1178 (Ilbert Collection)
Previous owner/ex-collection number: Q161 (Ilbert Ledger)