Accession No
0634
Brief Description
ivory diptych dial, by Jacob Karner, German, 1639
Origin
Germany; Nuremberg (Nürnberg)
Maker
Karner, Jacob
Class
dials
Earliest Date
1639
Latest Date
1639
Inscription Date
1639
Material
ivory; metal (brass); glass; rope (string)
Dimensions
length 93mm; width 62mm; depth 12mm; height when open 98mm
Special Collection
Robert Whipple collection
Provenance
Purchased from T.H. Court in 11/1930.
Inscription
‘IACOB 1639 KARNER’
Description Notes
Ivory with brass fittings, decorated on the outside of the tablets.
Leaf Ia: 32-point wind rose with 16 points named; all 32 points numbered 1 - 32 from East through South. Lid pierced to show N point of compass. (Brass index and wind vane missing.)
Leaf Ib: dial for planetary hours and length of day and night, with pin gnomon; planetary hours divided 1 - 12, numbered by 1; day/night hours divided 16 - 8 and 8 - 16, numbered by 1 and marked with zodiacal symbols. Attachment points for string gnomon at 51, 48, 45 and 42. Lead plumb bob (replacement). Table of towns and latitudes (see file).
Leaf IIa: horizontal dial for 42, 45,48 and 51˚ N, divided 4 - 12, 1 - 8, numbered by 1, subdivided to 30 minutes. Central inset compass with cardinal points marked; N-S line offset for magnetic variation approx 2˚E of N; maker’s mark ‘3’ stamped twice in base. Two subsidiary dials each with pin gnomon, one for Italian hours divided 10 - 23, one for Babylonion hours divided 1 - 14, both numbered by 1. String gnomon is a replacement.
Leaf IIb: 4 small brass feet. Table of epacts for 1627-1645 marked ‘EPACTA IVLIAN ANNO’ and ‘EPACTA GREGORI ANNO’. Lunar volvelle (missing rotatable disc).
Markings in black, red and green. Slot in leaf II to house wind vane.
missing plumb bob
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:39752
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