Accession No
1690
Brief Description
ivory diptych dial; made by Hans Troschel the elder; circa 1600
Origin
Nuremberg (Nürnberg); Germany
Maker
Troschel, Hans (the elder)
Class
dials
Earliest Date
1600
Latest Date
1600
Inscription Date
Material
ivory; metal (brass, steel); glass; rope (string)
Dimensions
width 49mm, depth 79mm, height 15mm
Special Collection
Holden-White collection
Provenance
On loan from The Fitzwilliam Museum, University of Cambridge. Donated by Charles Holden-White to the Fitzwilliam Museum. Holden-White collection no. 1935-44.
Inscription
‘HANS TROSCHEL’
Description Notes
Rectangular ivory diptych dial with brass fittings.
Leaf Ia: 32-point wind rose with 16 named points. Brass index in form of hand and finger. Motto ‘monstro viam perge secvrvs’. Leaf pierced and glazed to show N point of compass.
Leaf Ib: vertical dial with pin gnomon for day length ‘quantitas diei’, divided VIII - XVI, numbered by I and marked by zodiac symbol. Vertical dial for latitude 48˚ N, divided VII - XII, I - V, numbered by I; marked along sides ‘descensus’ and ‘ascensus’.
Leaf IIa: horizontal dial divided 4 - 12, 1 - 8, numbered by 1, subdivided to 15 minutes. Inset compass with cardinal points marked; offset 5˚ E of N for magnetic variation. Horizontal pin gnomon dial marked ‘horæ ab ortu et occasu’ for Italian and Babylonian hours, divided 10 - 23 and 1 - 14, numbered by 1.
Leaf IIb: lunar volvelle marked ‘dies ætatis lunæ et horæ noctis’ (disc missing). 4 small feet.
fair condition, ivory slightly cracked
missing plumbob
References
Events
Description
The Diptych dial is a common form of portable multi-function sundial. Diptych dials were made popular by the instrument makers in Nuremberg during the sixteenth and seventeenth centuries. They are usually made of ivory with brass fittings, and are often elaborately decorated. The name of the device derives from the Greek diptychos for a pair of folding writing tablets, which the instrument resembles.
Diptych dials consist of two leaves hinged together, with a string ‘gnomon’ stretched between the inner surfaces of the leaves for casting a shadow. To use the device as a sundial the lower leaf must be placed parallel to the horizon and the upper leaf must be at a right angle vertically to it. The gnomon must then be aligned with the meridian of the place where it is being used by using the inbuilt magnetic compass. Time can then be read from the horizontal or vertical dial by the location of the shadow cast by the string gnomon.
In addition to the horizontal and vertical dials, diptych dials normally carry a number of other features, such as equinoctial dials, windroses, tables of latitude for adjusting the string gnomon for different locations, epact tables, lunar volvelles for telling time at night by the moon, and various pin-gnomon dials for telling the time according to Babylonian or Italian hours, or for calculating the position of the Sun in the zodiac.
27/05/2009
Created by: Joshua Nall on 27/05/2009
FM:39766
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