7 feet 1 inch
Case of figured walnut veneers onto an oak carcass, hood with dome and raised top and cross-banded walnut plain frieze below, brass-capped Doric columns, with concave throat mouldings above the rectangular trunk door, concealing the pendulum beat scale to the backboard, the plinth with feather banded inlaid panel above a double footed skirt.
11 inch square silvered regulator dial with large subsidiary seconds set above the recessed hour sector signed Geo Graham London with finely sculpted blued-steel minute hand and counter-balanced seconds hand, pin-hole adjustment to the calendar aperture and bolt-and-shutter lever by 15, blued-steel securing screws to the dial feet with steel location pins.
6⅛ by 10 5⁄16 inch plates, tapering at the top, with six latched baluster pillars, Graham’s own deadbeat escapement, bolt-and-shutter maintaining power, T-bar suspended pendulum with brass section rod and massive lenticular bob with nosing to the rating nut. The movement secured by means of two bolts through the seatboard into the base pillars and by two robust T-form securing brackets to the backboard. The dial feet screwed to the front plate.
Possibly purchased from Graham by Don Fernando de Souza Coutinho de Castelo-Branco Menezes, 12th Earl of Redondo, Portugal, d. 1753.
Don Luis Fernando de Souza Coutinho Castelo-Branco Menezes, 3rd Marquis of Borba and 16th Earl of Redondo (1835-1928).
Thence by descent, and sold Sotheby’s, London, 8 July 2008, lot 387 (£211,419).
Garnier & Carter, The Golden Age of English Horology, 2015, p.178-183.
The Redondo Graham Regulator circa 1740-5
A very fine and rare Type 3 burr walnut month-going longcase regulator
One of only three square dial regulators in fine Phase 3 walnut cases.
Graham’s Deadbeat escapement
The first significant attempt to improve on the anchor escapement was the deadbeat. It was invented in c.1675 by the astronomer Richard Towneley, and first used by Thomas Tompion in a clock built for Sir Jonas Moore, and in the two (or possibly three) precision regulators he made for the new Greenwich Observatory in 1676, as mentioned in correspondence between Astronomer Royal, John Flamsteed and Towneley. George Graham adapted, redesigned and was the first to use it, as standard, in his precision regulator clocks.
Graham’s deadbeat escapement has two faces to the pallets, a ‘locking’ or ‘dead’ face, with a curved surface concentric with the axis on which the anchor rotates, and a sloping ‘impulse’ face. When an escape wheel tooth is resting against one of the dead faces, its force is directed through the anchor’s pivot axis, so it gives no impulse to the pendulum, allowing it to swing relatively freely. When the pallet on the other side releases the escape wheel, a tooth lands on this ‘dead’ face first, and remains resting against it for most of the pendulum’s outward swing and return. For this period the escape wheel is ‘locked’ and unable to turn. Near the bottom of the pendulum’s swing the tooth slides off the dead face onto the slanted ‘impulse’ face of the pallet, allowing the escape wheel to turn and give the pendulum a push, before dropping off the pallet. It is still a frictional rest escapement because the sliding of the escape tooth on the dead face adds friction to the pendulum’s swing, but it has less friction than the recoil escapement because there is no recoil force.
In contrast to the backward slant of the anchor escape wheel teeth, the deadbeat escape wheel teeth are radial or slant forward to ensure that the tooth makes contact with the ‘dead’ face of the pallet, preventing recoil.