Accession No
2801
Brief Description
astronomical regulator, month-going longcase clock, by J. R. Arnold, English, c. 1820
Origin
London; England
Maker
Arnold, John R.
Class
astronomy; mechanical horology
Earliest Date
1820
Latest Date
1820
Inscription Date
Material
metal (brass, silver, mercury); glass; wood (mahogany); string
Dimensions
height 1800mm; dial plate 280 x 279mm
Special Collection
Provenance
Transferred from Institute of Astronomy, University of Cambridge, Cambridge, England, 10/12/1981.
Inscription
‘John R Arnold London’ (face)
Description Notes
Astronomical regulator, month-going longcase clock, by J. R. Arnold, English, c. 1820.
Longcase regulator clock, month-going. Mercury compensated pendulum (NB Mercury now removed, 06/2018) with graduated rating nut below, silvered amplitude scale. Brass weight, cord line. 7-wheel train. Dead beat escapement with steel pallets. Square silvered dial plate with three dials - minutes and subsidiary hours and seconds. Inner wooden cover for movement. Square hood. Mahogany case with glazed trunk door.
Condition good; complete
References
Events
Description
An astronomical regulator is a fixed and highly accurate pendulum clock. A regulator dial has a large central minute hand, with the hours and seconds shown on smaller subsidiary dials within the centre of the face.
This astronomical regulator was made in the early 19th century for use in an observatory. It would have been used for (among other things) the timing of the transit of heavenly bodies as they passed over the meridian. In order to keep very accurate time, regulators such as this one include a mercury jar on the pendulum for compensating for temperature change, ensuring that the pendulum beats at the same rate even when it expands or contracts due to warming or cooling.
12/05/2014
Created by: Joshua Nall on 12/05/2014
FM:39926
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