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Play, download and edit the free video Admiral Howes Ellicott Regulator, Circa 1760 A historically important portable mahogany astronomical regulator.

Exhibit № 43
Admiral Howe’s Ellicott Regulator
Circa 1760

An historically important and rare George III portable mahogany cased astronomical regulator with Ellicott’s movement-fixed form of temperature compensation

Height
5 feet 7 inches (1700 mm)

Case
The tapered pylon-shaped mahogany straight-grained portable case, of simple dovetail-jointed box construction with absolute practicality in mind. The flat top with inset tapering dial door immediately below, mitred to each corner inset with a circular dial aperture and beaded to the edges. The case division rail below, affixed with an ivorine plaque reading Inherited from Admiral Richard Earl Howe, consolidating the case. The full trunk door aperture extending the full width and lower division of the case, the similarly inset beaded trunk door hinged and strengthened with inset mitred cleats top and bottom. The case division rail also supporting the ‘lockable’ movement seatboard, fronted by a slot-in dial mask with integral dust cover. The current mahogany pendulum locking pieces inside the trunk, made specifically to fit the original securing fittings.

Dial
The 8 inch (203 mm) circular silvered brass regulator dial, signed Ellicott London, with Arabic minutes outside the division ring, the subsidiary Roman hour sector below centre and subsidiary Arabic seconds ring, 5-60, above centre, all with blued steel hands.

Duration
8 days

Movement
The substantial 6 pillar precision movement, with deadbeat escapement, bolt and shutter maintaining power and Ellicott’s own temperature compensation, mounted to the movement. The lenticular brass bob, with flat iron pendulum rod, fixed to the suspension lever by its suspension spring, through the suspension block cheeks. The iron rod is simultaneously adjusted for expansion/contraction by a compensating flat bi-metallic bar causing the suspension lever to rise or fall by the same amount.

Escapement
Deadbeat with one second pendulum

Provenance
Arguably the well-documented regulator ordered by the Royal Society, and purchased from John Ellicott FRS for £35 8s, for the transits of Venus of 1761 and 1769;
Acquired by Admiral Richard, Earl Howe (1726-99) and thence by descent to:
John Knatchbull, 7th Baron Brabourne, to his wife;
The 2nd Countess Mountbatten of Burma, and sold in 2009 for £100,000;
The John C Taylor Collection, inventory no.182

Exhibited
c.1970-2005, Greenwich, The Royal Observatory, on loan to the museum from Lord Brabourne, a descendant of Admiral Howe

Literature
Antiquarian Horology, Spring 1977, Howse, ‘The Admiral’s Clock’,
(illus.) p.164-172
Roberts, English Precision Pendulum clocks, 2003, p.21 to 34, fig.12-7A

This transportable Astronomical regulator by John Ellicott FRS was obviously designed specifically for use on voyages of exploration and fitted with one of the two forms of temperature compensation designed and published by Ellicott in the Philosophical Transactions in 1753. But why Admiral Howe should have had such a clock, portable and designed specifically for scientific use, was the subject of Derek Howse article The Admiral’s Clock. He suggests:
Briefly, it seems possible that, perhaps through the interest of his erstwhile Board of Longitude colleagues, he might have been given the opportunity to acquire it from the Royal Society, who disposed of such a clock during the “resting” period between his resignation from the post of Treasurer of the Navy in 1770 and his appointment as Commander-in-Chief North America in 1776.

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