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Longcase Equation Regulator: M.5-1965

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Object information

Current Location: In storage


Longcase Equation Regulator


Clockmaker: Dutton, William




The clock has a month duration movement. The enamelled dial is signed ‘Wm Dutton/London’. A calendar ring in the arch rotates once per year and indicates the days of the month, months, signs of the zodiac and times of sunrise. The case is mahogany with fine mahogany veneer.

Dial: Gilt dial plate with break arch. Engraved rococo decoration in spandrels; this was covered by later repoussé silver spandrels (A-F catalogued separately) which have been removed. Chapter disc, calendar ring and age of moon ring all of fired enamel, with 'Wm. Dutton London' (m raised) inscribed on the centre of the chapter disc. A calendar ring in the arch rotates once per year and indicates days of month, months, and signs of zodiac each divided into 30 degrees, and times of sunrise. Inside this ring is a separate one which shows the age of the moon with each day divided into four. The phases of the moon are indicated by a rotating sphere with one half silvered and the other half painted dark blue. Mean time is shown by a pair of delicately pierced blued steel hands, and solar time is indicated directly by a gilt brass minute hand bearing an effigy of the sun. The right hand winding square is for winding the movement, the left hand one for setting the calendar. Movement: Four latched pillars to month timepiece movement with inverted train, escapement at the bottom to make room for the calendar and equation work. Dead beat escapement with Harrison type maintaining power and end plates to pivots of train and motion work. The drive to the calendar is taken from the first pinion of the train by a large wheel mounted with a clutch on the arbor with a squared end for resetting the calendar. The arbor carrying the calendar ring rotates once per year, and the calendar ring rotates once per year, and has mounted on its rear end the balanced equation cam. A bell crank follows the periphery of the cam, and has a rack which engages with a pinion connected to a differential gear assembly forming part of the motion work. The output from the differntial gear causes the solar time minute hand to move relative to the mean time minute hand. The screw on the hour wheel pipe which drives a vertical arbor mounted on the back of the dial. A pinion at the top of the arbor drives the moon through a spring clutch, and a bevel wheelon the moon arbor drives the age of moon ring. The pendulum has a nine rod gridiron compemnsation with a heavy bob and a regulating nut with thirty numbered divisions. The pendulum is suspended from a bracket on the seat board. Case: Mahogany caracase with fine mahogany veneer. Break-arch hood with reeded chamfered corners and panels formed in sides with applied mouldings. Sides of trunk originally cut away inside to permit swing of a very large pendulum bob in narow case, only 11 ½ inches outside measurement. Unsuitable bronze classical head on top of case, was replaced by old brass spire finial in 1985.


History note: Unknown before testator

Legal notes

Bequeathed by S.E. Prestige

Measurements and weight

Height: 196.9 cm
Height: 217.2 cm
Height: 77½ in
Height: 85½ in

Place(s) associated

  • London ⪼ England

Acquisition and important dates

Method of acquisition: Bequeathed (1965) by Prestige, Sidney Ernest


18th Century, Late
George III
Production date: circa AD 1775


The six silver mounts which were removed as unsuitable additions are catalogued as M.5A-1965 through to M.5F-1965. The bronze classical male head

Components of the work

Dial composed of enamel
Case composed of mahogany

Inscription or legends present

Inscription present: m is raised

  • Text: Wm Dutton/London
  • Location: Dial
  • Method of creation: Enamelled
  • Type: Signature

References and bibliographic entries

Identification numbers

Accession number: M.5-1965
Primary reference Number: 137658
Stable URI

Audit data

Created: Saturday 6 August 2011 Updated: Friday 31 March 2023 Last processed: Wednesday 13 December 2023

Associated departments & institutions

Owner or interested party: The Fitzwilliam Museum
Associated department: Applied Arts

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The Fitzwilliam Museum (2024) "Longcase Equation Regulator" Web page available at: Accessed: 2024-02-23 01:31:48

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{{cite web|url= |title=Longcase Equation Regulator |author=The Fitzwilliam Museum|accessdate=2024-02-23 01:31:48|publisher=The University of Cambridge}}

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