- Museum number
MOVEMENT AND DIAL OF A LEVER WATCH WITH INDEPENDENT CENTRE-SECONDS CHRONOGRAPH, PERPETUAL CALENDAR, MINUTE-REPEAT AND LUNAR INDICATIONS.
3/4-plate; going-barrel; ratchet-tooth lever escapement; split bi-metallic balance.
Slide-operated minute-repeat sounding on two gongs.
White enamel dial with Roman hours I-XII; minutes 5-60 and subsidiary dials for months, days of week, date and moon phase.
Blued steel hands.
- Production date
Diameter: 37.40 millimetres (back-plate)
Diameter: 40.90 millimetres (dial-plate)
Thickness: 13.20 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by M. F. Dent
London and Switzerland, 1892
Movement of a ratchet tooth lever chronograph with perpetual calendar, lunar indication and minute repeat.
Signature: On the dial 'DENT 33 COCKSPUR ST. LONDON'. On the back plate 'Dent Watchmaker to the Queen 33 Cockspur Street London No 30951 PARTLY SWISS'.(1)
Dial & Hands: A flat dial with four subsidiary dials. The seconds dial with a sunk centre pierced out to show the phases of the moon. Day and date dials with sunk centres and a month dial with a sunk centre showing the leap year. Signed 'WILLIS' in the counter-enamel. Blued-steel hands of spade and arrow design. The gold moon dial is enamelled blue with stars and two moons.
Dial-plate: None intended.
Dust-cap: None intended.
Ebauche Marks: 10499
Frame: Full plate layout with a separate bridge for the going train barrel, centre and third wheels. A cock for the fourth wheel, escape wheel and pallets and another for the balance. A further cock, mounted on the back plate, for the centre seconds pinion. One bridge on the inside of the front plate provides bearing for the pivot of the chronograph rocking pinion. Another bridge provides bearing for the repeating train pivots. The balance cock is engraved with foliate scrolls.
Barrel and Mainspring:
Barrel: going barrel, internal diameter 12.4 mm, height 2.4 mm.
Mainspring: height 2.3 mm, thickness 0.17 mm.
Barrel Arbor: diameter 4.9 mm, snailed.
Train: All the wheels gilded, the centre, third and fourth wheels with six crossings. A high quality train with high-count pinions, the wheels and pinions finished to a high standard.
Jewelling: Jewelled bearings from the third wheel onwards, the escapement with endstones throughout. The pivot holes for the repeating barrel and the repeating train jewelled. Also a jewel for the bottom pivot of the centre seconds wheel. The escapement jewels and the lower third jewel are in screwed settings all the others are rubbed in.
Escapement: An acute angle layout ratchet tooth lever escapement with short lever, double roller and triangular impulse pin. The enclosed pallet stones have convex impulse and locking faces. The gold dart on the lever is screwed and steady pinned in position.
An equal impulse escapement.
No. of teeth embraced 32.
Balance & Spring: A bimetallic balance with gold screws. Two quarter screws, and two timing nuts. Balance diameter 14.2 mm, thickness 1.25 mm. Blued-steel flat spiral spring with 172 turns with terminal curve attached to a rectangular steel collet on the balance staff.
Means of Regulation: An index on the balance cock registers against an engraved scale with 'F' and 'S' on the balance cock table.
Train Counts and Beat Rate:
Great wheel 76 (barrel)
Centre wheel 80 pinion 10
Third wheel 75 pinion 10
Fourth wheel 70 pinion 10
Escape wheel 15 pinion 7
Beat Rate: 18,000
Motion work: cannon pinion 12,
minute wheel 36, minute pinion 10
hour wheel 40 with wheel of 24 to drive the calendar work.
Chronograph work: A rocking wheel of 28 meshes with the fourth wheel. Also on the fourth wheel arbor is another fine toothed wheel which meshes directly with the centre seconds wheel. There are the normal three functions - stopped, going and return to zero, the levers being operated by a castle wheel.
Repeating Work: Slide-operated minute repeat mechanism striking on two steel wire gongs, the slide would have been in the case band. This is the most sophisticated type of repeating work with an isolator fitted to the quarter jumper so that it only operates during repeating and not all the time. It also has the divided repeating rack system.(2) The speed of striking is controlled by adjusting the depthing of the last pinion. See Glossary.
Perpetual Calendar Work: Mounted on a sub-plate and driven by a pinion of 24 leaves mounted on the hour wheel pipe. The calendar indicates the day of the week, the date and the month with an automatic adjustment for leap years.
Lunar Indication: The conventional moon wheel with 59 teeth is indexed twice per day by the hour wheel producing a complete a revolution in 29 2 days to show the phase of the moon.
Winding System: Side-set rocking bar keyless winding, the barrel ratchet wheel with wolf-tooth gearing.
Movement: diameter 42.0 mm, height 13.0 mm.
Provenance: Formerly in the Ilbert Collection. Ilbert purchased this from Contarde on 27.3.1937.
(1) A superb example of combined English and Swiss work, this watch was made for M. F. Dent by Nielsen (Emile Nielsen of Nicole Nielsen) in 1892, see Mercer, 'Edward John Dent And His Successors', p.704. It shows that even Nicole Nielsen did not always make all the components of their watches even though they clearly had the means and expertise to do so. It was presumably more economic for them to have the complications added to the watch in Switzerland. It is likely that the basic frame etc. would have been made in England and that the chronograph, calendar and repeat functions were added in Switzerland. For an ebauche of a very similar watch see cat. no. 300 (registration no. 1958,1201.1389). This ebauche demonstrates the stage at which the watch would have been returned to England from Switzerland for finishing.
- Not on display
Latest: 2 (2017)
- 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.0978 (Ilbert Collection)
Previous owner/ex-collection number: P151 (Ilbert Ledger)