Bonhams 1793 : A fine George III mahogany longcase regulator signed "Josiah Emery, Charing Cross. London," circa 1785

20 Jun 2012 14:00 BST London, New Bond Street
Fine Clocks
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A fine George III mahogany longcase regulator

signed "Josiah Emery, Charing Cross. London," circa 1785
Case: The mahogany veneers of good figuring set on an extremely substantial tapering case of solid mahogany, the shallow arched hood with canted front angles over the conforming trunk door and spreading base on double apron, the interior of the case fitted with sliding glazed panels forming a partition to enclose the pendulum and offer a microclimate.

Dial: the one-piece silvered dial signed in the shallow arch 'Josiah Emery, Charing Cross, London' over a concentric Arabic minute ring with blued steel heart-tipped hand, enclosing the Arabic subsidiary seconds dial with Observatory marks and extremely fine seconds hand, the hours shown in a sector-shaped cartouche below centre (the hour ring engraved on both sides; 1 - 24 on one side and twice 1 - 12 on the other), secured to the front-plate by four heavy dial feet, each with three screws.

Movement:
the plates measuring 5mm in thickness and united by six knopped pillars, the movement protected by sliding brass shutters running in grooves at the plate edges, set on a heavy mahogany seatboard. The dead beat escapement employing an unusual V-shaped anchor having curved impulse pallet faces with concave entrance and convex exit surfaces intended to equalize impulse, Harrison's maintaining power, fully end capped high-count train with the 'scape wheel and anchor arbors jewelled, all wheels finely cut and with six crossings.

The gridiron pendulum of the form introduced by John Arnold, consisting of two zinc and three steel rods, suspended from a substantial back cock on the movement, beat adjustment by means of screws on the suspension block, pendulum rod fitted with an open work, lozenge-form, brass and steel brace to engage the crutch, large brass-clad bob pierced with rectangular openings forming a bridge acting as the point of suspension, placing the bob's center of gravity on a screw threaded into the lowest cross piece of the pendulum, rate adjustment by means of calibrated rating scale on this screw, a further spherical fine adjustment weight below the bob the screw terminating with an index to the silvered beat scale within the case.

2.01m (6ft 7ins) high.

Sold for £12,500 inc. premium

Footnotes

A technically innovative regulator whose gridiron pendulum could have been supplied by Emery's colleague and neighbour, John Arnold. The highly finished dead beat escapement employs the pallet geometry introduced by A.-L. Breguet for his first lever watches.

The influence of Emery on the development of the lever escapement for watches is widely acknowledged and it is interesting that these unusual pallets should be found on a regulator by Emery. Curved pallet faces are otherwise encountered on a few of the early lever watches by A.-L. Breguet. In addition, his locking faces are concentric with the axis of the lever [i.e. anchor] as in a dead beat escapement.

Daniels describes Breguet's earliest lever watch, made in 1786, and suggests that he learned of the escapement through his friendship with John Arnold who introduced him to the work of John Leroux and Josiah Emery. The initial forms of Breguet's lever mirror the deadbeat anchor of the present clock.

The movement shows signs of alteration, but because of its unusual pallet geometry, the clock may have been somewhat experimental. It appears that the layout of the train was changed during the course of manufacture. Filled holes in the front plate match the dimension and geometry of the steady pins for the present end caps for the anchor and third wheel arbors. However, the plate was never tapped for securing screws at these positions, suggesting the locations were experimental and related to changes in the design of the anchor.

In addition, there are filled holes in the back plate which correspond to where the back cock was first planted, lower on the plate. It was then moved higher and replanted in its present position. The right foot still retains a cut out that formerly accommodated the third wheel end cap.

Category: Clocks and Watches / Clocks

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