- Museum number
Mechanical universal equinoctial dial; gilt brass and silver; octagonal; wooden case covered in brown leather; dial should open automatically to pre-set latitude governed by face cam marked for 0-60 degrees(spring missing); flat alidade rotating on polar axis; equatorial circle; subsidiary silvered dial; compass box with adjustable brass index; signature; list of towns and latitudes on underside.
Width: 79 millimetres
- Curator's comments
This instrument is similar to one (said to represent an early form of mechanical dial developed by Michael Bergauer) in the collection of the Greenwich Maritime Museum, reg. no. AST0469, as well as to another instrument in the British Museum, reg. no. OA.384, and to instruments at the MHS, Oxford, new inv. no. 51664 and the National Technical Museum, Prague; see H. Higton, Sundials at Greenwich, Oxford 2002, no. 165, pp. 181-2.
With the aid of a spring, now missing, the dial should open automatically to a pre-set latitude governed by a face cam marked for 0°-70°, underneath the dial-plate. A flat alidade rotating on a polar axis is turned by hand until its shadow lies in its own plane and so disappears. The hour is then shown by an index on an equatorial circle numbered I-XII, I-XII and the minute past the hour on a subsidiary silvered dial by means of a 24:1 step-up gearing. The hour numerals and half and quarter divisions are filled with red enamel, and the centre of the dial is pierced and engraved with sprays and scrolls.
The compass box is marked for true compass points but an adjustable brass index is provided for setting to any required declination. Above the box is the signature: MICHAEL BERGAUER INSPRUG; and the remainder of this face is occupied by engraved scrolls and strapwork. A plumb-bob is provided for levelling. On the underside of the base is a list of twenty-two European towns and also Jerusalem, with their latitudes in degrees and minutes of arc, and there is further scrollwork.
- Not on display
Latest: 2 (Nov 2016)
2 (Jul 2015)
2 (Nov 1995) Spring missing.
- Acquisition date
- Britain, Europe and Prehistory
- Registration number