- Museum number
Enamel dial; independent split seconds; subsidiary dial showing quarter seconds.
Gold hunting case.
- Production date
Diameter: 55.10 millimetres (case)
Thickness: 28.20 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by Jules Jürgensen
Switzerland, c. 1885
Gold cased independent split seconds watch with a club tooth lever escapement.
Signature: On the train bridge 'Jules Jurgensen'. On the back of the inner dome 'Jules Jurgensen No. 7788' with the number repeated inside the dome. In both the case back and the case front 'JULES JURGENSEN 7788' with additionally in the front 'K 18'.
Case: 18 carat gold hunter case, engine turned on both back and front. The middle reeded. The hunter glass is missing.
Dial and Hands: A flat cannister dial with a sunk centre and sunk subsidiary seconds dial. The subsidiary seconds hand revolves once in four seconds. Around the minute circle which is numbered at every fifth minute is another circle marked at every ¼ second. Moon hour and minute hands of blued-steel.
Ebauche marks: none
Frame: A nickel silver frame. A bridge for the barrels another for most of the independent train although the flirt shares a cock that locates the going centre and third wheels. Another cock supports the fourth and escape wheels. The pallet bridge is steel. Scratched on the front plate is 1268694.
Barrels and Mainsprings: Hanging barrels with Geneva stopwork to both of the barrels.
Going barrel I diameter 13.5 mm., height 2.6 mm.
Mainspring height 2.4 mm., thickness 0.15 mm.
Arbor: diameter 4.5 mm., not snailed.
Independent barrel diameter 13.3 mm., height 3.5 mm.
Mainspring height 3.2 mm., thicknness 0.175 mm.
Arbor: diameter 4.7 mm., not snailed
Train Wheels: All brass wheels and with five crossings except as below. Some wheels gilded one side, some not easily visible from the back not gilded at all. The ratchet tooth wheel on the escape arbor is gold. Four crossings for the steel escape wheel.
Jewelled: Both trains fully jewelled except for the front going arbor pivot and the front first arbor pivot. All jewels rubbed in. The escapement with ruby endstones, that in the escape cock in a gold setting.
Escapement: Club tooth lever, straight line layout, short lever, double roller, impulse pin D shaped. A mixed escapement. Pallet stones convex on the impulse and locking faces. The escape wheel steel, with chamfered teeth.
No. of teeth embraced 3½.
Balance: Split bimetallic balance diameter 15.0 mm., thickness 1.15 mm. Blued-steel flat spiral spring with 17 turns and a terminal curve. Stud clamped and radially adjustable.
Means of Regulation: Index on the balance cock registering against a divided scale on the train bridge with engraved 'FAST SLOW' and '1, 2, 3' one side of zero, '1, 2, 3, 4' on the other side.
Train Counts and Beat Rate:
Great wheel (barrel) 76
Second wheel 80 pinion 10
Third wheel 75 pinion 10
Fourth wheel 56 pinion 10
Escape wheel 15 pinion 7 (with ratchet toothed wheel on the arbor of 30)
Beat Rate: 14,400
1st wheel 48 pinion 10
2nd wheel 44 pinion 12
3rd wheel 48 pinion 12
4th wheel 60 pinion 12 (This carries the centre seconds hand)
5th wheel 48 pinion 8
Fly pinion 6 with two star wheels of 4, one loose and connected to the other.
The escape wheel revolves once in 3 ¾ seconds so the flirt moves forward in 30 x 1 seconds.
that is ¼ second.
Since the flirt pinion revolves once a second the relation to the centre seconds pinion must be 60:1 i.e. 60 x 48
The linkage between the two centre seconds hands is through a heart cam and roller follower, the roller is a jewel. The three actions as dictated by the castle wheel are thus: 1. both hands stopped 2. one hand stopped 3, both hands going and superimposed. There is no way of returning these hands to zero. The castle wheel is turned by a lever operated by a plunger in the case at '12 o'clock'. A screw head protrudes from the plunger and enters a recess in the rim of the front cover and prevents the operation of the plunger when the cover is closed.
Motion Work: Wheel on the second arbor 40, the cannon wheel 40. Minute wheel 40, pinion 6, Hour wheel 72.
Winding System: Side lever set keyless work, the front cover disengages this lever when it is closed. Winding of the going barrel is effected by turning the button in one direction and of the independent barrel in the other.
Dimensions: Case diameter 55.3 mm., height 18.0 mm.
Movement diameter 45.7 mm., height 11.8 mm.
Provenance: Formerly in the Ilbert collection. Ilbert purchased this from Malcolm Gardner 28/11/1931.
1. For a similar watch, although not split seconds, see Watches by Clutton and Daniels 3rd Edition 1979, ill. 322 a and b. This watch is numbered 8573.
2. The PATENTS referred to are 4l64 of 27th September l88l and the other 2856 of 22nd February l890. Details follow:
Chronographs: Consists in an arrangement by which an extra minute hand and dial index, and an extra seconds hand, are shown on the usual dial face or on a back dial if preferred. Upon the arbor of the fourth wheel is placed a motion wheel E, Figs. 2 and 3, working a wheel F, which carries a friction wheel G, working another friction wheel H, upon an arbor I, which, passing through the hollow arbor of the centre wheel, carries the extra seconds hand C, Fig. l. A tooth K upon the wheel H actuates a ratchet wheel L, whose arbor M carries the extra minute hand A. The starting, stopping, or returning of the hands A and C is effected by the winder N acting as a push piece upon a slide P, Fig. 4, which is held in position by a spring P, and carries the click R gearing into the ratchet wheel S, both of which are kept to their work by the springs R and S. The ratchet wheel S carries a star piece T, which moves the three clicks at one pressure of the push piece. The first pressure causes the click V to pass under the lifting spring Y, thus raising the seconds hand C out of gear. On a second pressure the click W, falling upon the heart cam H of the wheel H, returns the hand C to the starting point, while simultaneously the hand A is also returned by the action of the third click falling upon the cam L of the wheel L, the double spring Z keeping both clicks to their points of contact. The next pressure of the push piece N releases the clicks from the cams H, L and withdraws the click V from the spring Y, thus allowing the extra hands to fall into gear. The wheels E,F may be replaced by three bevel wheels. In another arrangement the movement of the extra minute hand may be directly effected by the great wheel b, Fig. 5, by means of a small bevelled wheel c upon the arbor M, brought in and out of gear by the click V; or a flat motion wheel may be geared into the wheel b and made to work freely upon a stud drilled for the passage of the arbor M, which carries a rough disc rising out of and falling into gear upon the said motion wheel. The bevelled wheels G and H may be replaced by two fine wheels with straight edges working in conjunction with the wheels E and F; or three friction wheels, with straight edges may replace the wheels E,F,G,H.I.
3. See The Jurgensen Dynasty - Three Centuries of Horology in two Countries by Charles Kalish, La Suisse Horlogere et Revue International de L'Horlogerie No 2, 78th Year pp 45-56 and in issue 3 pp 37-48.
- Not on display
- Latest: 2 (2017)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1126 (Ilbert Collection)
Previous owner/ex-collection number: L137 (Ilbert Ledger)