Accession No
0565
Brief Description
universal equinoctial dial, German, 18th Century
Origin
Germany
Maker
Class
dials
Earliest Date
1700
Latest Date
1800
Inscription Date
Material
metal (gilt brass, silver, steel); glass
Dimensions
length 82 mm; breadth 57 mm; thickness 16 mm
Special Collection
Robert Whipple collection
Provenance
Purchased by Robert Stewart Whipple from Antique Art Galleries, Grafton Street, London, England on 30/10/1929.
Inscription
'This Precious Stone Set in a Silver Sea' (on lid)
'Atlantic Ocean, British Ocean, Irish Sea, English Channel; England, Wales, Scotland, Ireland' (annotated map on lid)
Description Notes
Oval gilt-brass case; on the outside of the lid a later engraved map of the British Isles with the text ‘This Precious Stone set in a Silver Sea’. Inside of lid carries lunar volvelle. Inside box an inset compass with silvered base; cardinal points marked in Latin. Plumb bob on gallows. Hinged silver hour circle segment divided on outer (inner?; 26-1-2000) rim [3] - 12, 1 - [9], numbered by 1, subdivided to 15 minutes. Pin gnomon extending either side of a diametrical bar. Hour circle adjusted for latitude by cam-operated scale divided 30˚ - [70˚], numbered by 10˚, subdivided to 1˚.
Condition: good/fair.
References
Events
Description
The universal equinoctial ring dial was designed by the English mathematician William Oughtred in the first half of the seventeenth century. It could be used at any latitude, so was a popular timekeeper for sailors and other travellers. It was really a much simplified version of the armillary sphere, only keeping the parts which were needed for telling the time.
The universal equinoctial ring dial consists of two rings and a bridging bar inside the inner ring. The outer ring represents a circle passing through the North and South celestial poles. The inner ring is called the ‘equinoctial’ ring because it represents the celestial equator. The bridging bar represents the axis of the world, just as the gnomon on an ordinary horizontal dial does. So the instrument is a very simple model of the heavens.
01/02/2001
Created by: Dr Hester Higton on 01/02/2001
FM:43215
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