- Museum number
Split seconds watch.
Full-plate; fusee; Harrison's maintaining power.
White enamel dial, Roman hours, subsidiary seconds below XII.
Gold hour, minute and seconds hands, blued steel independent seconds hand.
Silver gilt case with hallmark and maker's mark. Minutes 0-60 around the bezel. Pendant maker's mark.
Split-seconds operated by a push-piece in the pendant and indicated by two seconds hands on the subsidiary seconds dial.
Stop lever intercepts the balance.
- Production date
- 1837 (hallmarked case)
Diameter: 53.50 millimetres (case)
Diameter: 48.70 millimetres (dial)
Thickness: 21.60 millimetres
- Curator's comments
The signature on the dial has been altered. The area after ARNOLD has been
erased and over-written with 84 STRAND. It was probably signed ARNOLD AND DENT originally, a style of signature which would agree with the hallmark date.
The watch may have been a timer used in-house which had its dial inscription changed when Dent left Arnold to set up business in his own right.
Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by John Roger Arnold & Edward John Dent.(1)
Silver-gilt cased ratchet tooth lever stop-watch with split seconds.
Signature: 'ARNOLD 84 STR LONDON 5232' on the dial. '4 STR' replaces something which has been erased and is over painted.1 'ARNOLD 84 STRAND' on the back plate and 'London No 5232' on the barrel bridge.
Case: Silver-gilt consular case, numbered in both backs 5232, with the London hallmark for 1837 and with the casemaker's mark JD.(2) The pendant punched on the front with hallmarks and on the back with the maker's mark WC in cameo.(3) The bezel numbered 5-60 around the edge. The reason for this numbering is obscure. A push piece runs through the pendant to operate the stop-mechanism.
Dial & hands: Flat dial with a subsidiary seconds dial at XII o'clock. Numbered '32' in black and '52' in feint red in the counter-enamel. Gold moon-pattern hour and minute hands, the latter repaired. Two seconds hands, the upper, gold hand for normal seconds, the lower blued-steel hand for split seconds.
Dust-cap: None intended.
Ebauche marks: 5232 18 4 and four dot marks on the front plate.
Frame: A full plate layout, the back plate supported by four turned pillars. The back plate, the barrel bridge and plain balance cock are all numbered '5232'. There is a separate cock on the front plate for the fusee. The centre wheel and third pinion are recessed into the front plate, the latter with its pivot running in a proud bush on the dial side of the front plate. The balance cock has been filed away on the underside of the table to clear the balance, possible as a result of repairs. The remains of a punched number 8 are evident on the balance cock foot.
Fusee, Barrel and Mainspring:
Fusee: five-turn fusee with Harrison's maintaining power, the maintaining ratchet wheel of steel.
Barrel: flanged at the cap end and relieved at the base to clear the fusee. Internal diameter 17.0 mm, height 3.9 mm.
Mainspring: height 3.6 mm, thickness 0.23 mm.
Barrel Arbor: diameter 5.4 mm, not snailed.
Train: Gilded wheels, the centre wheel solid, the third and fourth wheels with five crossings.
Jewelling: Jewelled bearings for the fourth wheel in the front plate, the escape wheel and the balance. Ruby endstones for the escapement, in screwed settings. The balance jewel in the potence has a ruby endstone and the endstone in the balance cock is a diamond.
Escapement: A right-angle layout ratchet tooth lever escapement with short gold lever, single roller and round impulse pin. The enclosed pallet stones have convex impulse and locking faces. The gilded escape wheel has three crossings.
A mixed impulse escapement.
No. of teeth embraced 32.
Balance & Spring: An Earnshaw-type split bimetallic balance with brass compensation screws and steel quarter screws. Balance diameter 20.7 mm, thickness 1.6 mm. A blued- steel flat spiral spring with 8 turns attached to a polished steel stud, screwed to the back plate.
Means of Regulation: An index on the balance cock registers against a divided scale with 'Fast' and 'Slow' engraved on the balance cock table.
Train Counts and Beat Rate:
Great wheel 60 (fusee)
Centre wheel 64 pinion 8
Third wheel 60 pinion 8
Fourth wheel 56 pinion 8
Escape wheel 15 pinion 7
Beat Rate: 14,400
Motion Work: cannon pinion 12
minute wheel 36, minute pinion 14
hour wheel 42
Stop Mechanism: A lever between the dial-plate and the movement causes a flat blued-steel spring to act on the balance rim causing the whole train and the split-seconds device to stop.
The split seconds device: The split second mechanism is operated by a pendant plunger which depresses a one-piece sprung lever mounted on the front plate allowing a brake lever to descend onto a loose wheel under the influence of its own spring. The loose wheel rides on the extended fourth wheel arbor and carries the split seconds hand underneath the main seconds hand. Projecting down from the loose wheel close to the rim is a pin. Friction mounted on the extended fourth wheel arbor is an arm which extends beyond the edge of the loose wheel. The tail of the arm is a stud to which is pinned the outer end of a spiral spring, the inner end being pinned to the centre collet of the loose wheel. Normally the whole assembly moves as one with the pin on the loose wheel resting against the trailing edge of the arm. When the brake lever is applied to the edge of the loose wheel, the main seconds hand continues to move normally but the secondary seconds hand stops and the arm separates from the pin, winding up the spring. When the pendant plunger is released the secondary seconds hand will catch up with the seconds hand under the influence of the spiral spring and the two hands continue together. If the pendant plunger remained depressed the pin on the loose wheel will contact the front of the arm in just under a minute and stop the watch. Therefore, only intervals of less than a minute can be timed and the hands cannot be zeroed. For a drawing of a similar but not identical mechanism see cat. no. 190 (registration no. 1858,1201.1146).
Winding System: Key wound.
Case: diameter 52.7 mm, height 21.0 mm.
Movement: diameter 47.6 mm, height 15.0 mm, pillar height 3.9 mm.
Provenance: Formerly in the Ilbert Collection. Ilbert purchased this from Ash in 1932.
(1) This watch was almost certainly inscribed Arnold and Dent, the title of the firm between 1830-1840, intimating that this watch was sold after the partnership was dissolved.
(2) The mark of James Dow registered 7.9. 1835 of 54 Percival Street, Clerkenwell.
(3) The mark of William Collier registered 11.3.1831 of 54 Bath Street, Clerkenwell.
Literature: Mercer, Arnold and Son, pl. 203 and p. 173.
- Not on display
Latest: 2 (Feb 2019)
5 (Jan 2019) weeping
5 (date?) weeping
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1243 (Ilbert Collection)
Previous owner/ex-collection number: M153 (Ilbert Ledger)