An eight-day grande sonnerie parquetry longcase clock by Thomas Tompion, London, circa 1682.

The twin train movement has rectangular brass plates which are united by six latched knopped and finned pillars (with the exception of the lower central pillar which is neither pinned nor latched). The going train employs an anchor escapement and seconds beating wire-rod pendulum with brass faced lenticular bob which is suspended to a separate suspension block and the suspension spring passes through a pair of chops mounted to the back cock. The striking train sounds the hours on a low bell and the quarters on a high bell. A countwheel system is employed, the large pivoted countwheel is divided so that it counts the hours and the quarters in a single division. The countwheel is mounted in tandem with a cam wheel which governs the two hammers, each with sprung pivoted tails that are engaged or disengaged from the pin wheel by means of the cam follower. The countwheel is pivoted on the backplate by a chamfered iron bridge and is driven by a sixteen toothed pinion of report. The countwheel has the hours and quarters engraved onto the silvered toothed wheel which runs against a blued steel pointer. In a twelve hour period the clock performs 768 hammer blows and as such requires a considerably heavier driving weight than the going train.

The engraved inscription on the backplate reads ‘Made AD 1638 by Tho. Tompion, Londini, for the Earl of Strafford. Restored 1882’ and in itself is almost a catalogue of engraving styles popular in the 19th century from the traditional cursive script to the bold ‘Londini’ which is cut with a patterned roller.

The ten-inch brass dial is signed 'Tho. Tompion Londini Fecit' to the lower edge within the finely engraved wheatear border. The nine-inch silvered Roman chapter ring has outer Arabic five minute marks, inner quarter circle and sword hilt half hour markers, the gilt matted centre has an inlaid concentric (formerly) blued-steel band running just inside the chapter ring enclosing the calendar aperture and subsidiary seconds dial.

The oyster veneered parquetry case has a flat topped hood with a moulded cornice over barley twist columns and glazed side apertures, the convex moulded trunk has an ebony moulded door and glazed lenticle and rectangular base standing on bun feet.