Accession No
0664
Brief Description
universal equinoctial ring dial, Dutch, 1734
Origin
Holland (Netherlands)
Maker
Class
dials
Earliest Date
1734
Latest Date
1734
Inscription Date
Material
metal (brass)
Dimensions
length 132mm; diameter 104mm
Special Collection
Robert Whipple collection
Provenance
Purchased by Robert Stewart Whipple from Antique Art Galleries, Grafton Street, London, England on 12/02/1931.
Inscription
‘LUX IN TENEBRIS LUC ET MET IT URQUE DIES Joes. c:1:v:5:Trav: Senec’ (reverse of equinoctial ring)
Description Notes
Meridian ring calibrated for Northern latitudes, divided [0] - 90˚, numbered by 10˚, subdivided to 1˚. Suspension shackle with brass suspension ring. Equinoctial ring divided I - XII, I - XII, numbered by I, subdivided to 15 minutes; inner face only subdivided to 1 hour. Pierced bridge with date scale divided to named (initialled) month, subdivided to 10 days; reverse carries declination scale divided 22˚ - 0 - 20˚, numbered by 10˚, subdivided to 2˚ (1st Aries = 10 March); pinhole gnomon.
Reverse of meridian ring marked with altitude quadrant, divided [0] - 90˚, numbered by 10˚, subdivided to 1˚. Obverse carries list of towns and latitudes (see history file).
Condition: good.
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:40002
Images (Click to view full size):
