A unique and quite remarkable early 19th century weight driven skeleton clock with experimental esca
Lot 118W
A unique and quite remarkable early 19th century weight driven skeleton clock with complex experimental escapement Invented by James Wright, made for him by the clockmaker George Andrew Jepson in 1826
Sold for £31,200 (US$ 48,928) inc. premium

Lot Details
A unique early 19th century skeleton clock on collumn stand by 'Jacopo Wright/Jepson'
A unique and quite remarkable early 19th century weight driven skeleton clock with complex experimental escapement
Invented by James Wright, made for him by the clockmaker George Andrew Jepson in 1826
The dial
The silvered brass dial consisting of four interlinked circles, measuring between 2.5 and 8.5 inches in diameter; the smallest showing running seconds and engraved in Arabic fives around an engraved band, the second partially etched in black with an open centre revealing the hour, the third with banded decoration to its periphery and carrying the full signature
"Inventum
a Jacobo Wright quondam Coll:
Hert et nuper Aul Mag: Oxon
1826
Jepson Fecit."
and the largest in the form of an open centred ring showing minutes, again, marked in Arabic fives with an engraved band to the inner edge, with original blued steel hands. The seconds are shown on the uppermost dial via a running hand advancing every two seconds. The minutes are shown on the largest dial and are driven directly from the centre wheel. The hours are displayed through an aperture and are shown on a weight-activated jumping hour system; on the half hour, a three-wheeled pin begins to lift a weight set below the hour dial, as the minute hand revolves, the weight is lifted over a pulley so that precisely on the hour, the pin is released and the hour jumps forward.


The Movement
The lead weight fixed on a double pulley to give longer duration and driving a barrel of 16 turns, wound via a protected winding square accessible only on pulling forward the hinged thermometer plate, to a series of three geared winding wheels; the great wheel driving a 16 leaf pinion to a 360-toothed centre wheel measuring 10 inches in diameter with six finely shaped tapered crossings, directly driving the minute hand; the centre wheel also drives a 6 leaf pinion linked to a substantial, solid steel 30-toothed 'scape wheel. The scape wheel is controlled by a wedge shaped sapphire entry pallet acting in conjunction with a jewelled
deadbeat-type exit pallet. These pallets are set onto an ingenious system of counter-balanced pivotted levers that transfer impulse to the gilt wood 'dumb bell' balance mounted above, set on a knife edge suspension, and terminating at each end with a turned brass timing disc, japanned black and offering some form of micrometer regulation via a pair of endless screws.

All of the above is set within a heavy brass frame, the plates measuring 5/8ths of an inch thick and cast in the form of a stylised hour glass united by four plain turned pillars
All protected from the elements and probing fingers by a rectangular framed glazed hood that.

The case:
In two parts, the upper section a rectangular-section mahongany plinth that carries the movement and dome, set with a moulded cornice over a recessed centre panel and crisply carved foliate volutes to each corner, applied to the front with a 12 inch long mercury thermometer with large bulb and engraved silvered scale measuring from minus 10 to plus 110 degrees, the brass scale itself hinged at the right hand side and when opened will display the shuttered winding square for the winding arbour; this plinth is further set on a circular-section column terminating in a short socle and square base on squat bun feet
Total height including the dome is 2.05m (6ft 9in) high. Movement frame height 27cm (10.5in) high.

Footnotes


  • Literature: This clock is illustrated and discussed in Royer Collard; Skeleton Clocks, NAG Press, pages 104-105.



    The escapement is shown above with the balance and rear balance cock removed.

    The giltwood balance with knife edge suspension pivoted at point A, with an adjustable impulse pin which slots into the counter-balanced crutch (B) . As the ‘scape wheel exits, the impulse face on pallet F engages the locking pallet E by pushing down on the jewelled face G, controlled by the weighted equilibrium bar D, the exit bar H returns releasing the exit pallet which transfers impulse to the balance via jewelled face G and the counterweight I positioned at the end of bar H. The action of the escapement is controlled by two counter-balanced weights C , the left-hand weight can be seen clearly in the illustration, the right-hand weight has had the cock removed for the illustration and the polished screw tail (attached to bar H) engages with a polished steel wedge thus lifting the weight and damping the action.


    James Wright was, in modern terms, a mature student. The son of William Wright, gentleman of Lambeth, he matriculated at Hertford College, Oxford in 1813 at the age of 32. It is not known what he studied, but he obviously had a mind geared toward horology. The clock that he conceived uses a very fresh approach and does not use any springs, instead it relies on counterpoised steel levers, all terminating in threaded weights to offer almost endless amounts of regulation and fine tunning.

    The only Jepson listed as working in the early 19th century is a George Andrew, based in Nottingham who was declared insolvent in 1811. It may well be that after his insolvency, George travelled south loking for work and was settled in Oxford by the 1820s. We can only guess how long Jepson would have spent on creating such a machine, but bearing in mind that almost every piece is unique, it would have been a huge undertaking to cast the frame, the wheels and the incredibly complex series of steel levers. That is still runs today is a fitting tribute to the ingenuity of Wright and the skill and tenacity of Jepson.

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