- Museum number
The stamped inscriptions on this ivory diptych dial are mainly filled with black and red colours. Two brass clasps allow the dial to be closed, one clasp attached to the opposite side holds the dial in the open position while being used. A pivoted arm on the front edge of the lower leaf covers a hole which presumably once contained a pin gnomon.
The OUTER surface of the UPPER LEAF consists of a lunar volvelle and a windrose. The lunar volvelle, for converting lunar into solar time, consists of a movable brass disc with an index and a 24 hour dial, numbered twice 1 to 12. The centre is decorated with a sun effigy. A circular aperture shows the phases of the moon on the underlying ivory while a square aperture shows the age of the moon numbered 1 to 29. The pin gnomon is missing.
Surrounding the volvelle is a windrose with 32 directions marked in abbreviated German with full, half and quarter compass points, numbered by 1 and starting with East. South is additionally marked with a cross. A circular aperture positioned at north enables one to read the compass on the inner leaf.
Outside the windrose are the usual markings for the direction of sunrise and sunset, and for midday and midnight in German ('Aufgang', 'Nidergang', 'Mittag', and 'Mitternacht'). Above and below it is an inscription in Latin.
The INNER surface of the upper leaf consists of a pin gnomon dial for unequal hours (marked in red) with zodiacal signs and corresponding hours of daylight (numbered on the right-hand side from 8 to 16) and.darkness (numbered on the left-hand side from 16 to 8). Above and below it is an inscription in German.
Below is a string gnomon dial (string broken) numbered VI to XII to VI and divided to 1/2 and 1/4 hours. In the centre of the string gnomon dial is an equatorial pin gnomon dial (pin missing) on a gilt brass dial. The dial has a 24 hour scale, numbered anticlockwise twice 1 to 12, with a sun effigy in the centre.
The signature of the maker and place of production are inscribed at the bottom.
The INNER surface of the LOWER LEAF consists of a horizontal string gnomon dial, numbered 4 to 12 to 8 and divided to 1/2 and 1/4 hours. In the centre is a compass with a two deviations: circa 7° E (partially erased) and circa 10° W. The right and left top corners are decorated with blowing faces. The left and right-hand sides are decorated with vertical borders of stars and geometric shapes.
Below this is a pin gnomon dial with Italian hours, numbered 9 to 22 (black), and Babylonian hours, numbered 2 to 15 (red). The pins of the pin gnomon dials on the inner surfaces of the upper and lower leaves fit into small holes on the opposite leaves. Below the pin are inscribed the date and the motto 'SOLI DEO GLORIA'.
On the eastern edge of the lower leaf is a brass latitude scale from 10° to 70°, numbered in 10 degree intervals and subdivided into unmarked 2 degree intervals. A strut to set the dial to the appropriate latitude is missing.
On the western edge of the lower leaf are epact tables for the Julian and Gregorian calendars, starting with the year 1599 as follows: 'EPACTA IVLIA ANO 14 25 6 17 28 9 20 1 12 23 4 15 26 7 18 29 11 22 3', for the Julian calendar and 'EPACTA GREGO ANO 4 15 26 7 18 29 10 21 2 13 24 5 16 27 8 19 1 12 23' for the Gregorian.
The OUTER surface of the LOWER LEAF is inscribed with a latitude list of 40 European places in two columns as follows: 'MOSCOVIA 62', 'LIVONIA 60', 'LITVONIA 55', 'K?NIGSPERG 55', 'DANCZIG 54', 'LVBECK 54', 'CRACA 51', 'LEIPCZIG 51', 'PRAGA 50', 'ANTORF 50', 'COLONIA 50', 'COBOLENCZ 49', 'FRANCKFORT 49', 'NORIMBERG 49', 'AVGSPVRG 48', 'WIENNA 48', 'RENGSPVRG 48', 'PARIS 48', 'COSTNICZ 47', 'BASEL 47', 'MAILAND 45', 'VENETIA 45', 'LEON 45', 'GENVA 44', 'FERRARIA 44', 'VERONA 44', 'PATVA 44', 'FLORENCZ 43', 'MARSILIA 43', 'BONONIA 43', 'NEAPOLIS 42', 'ROMA 42', 'PORTVGAL 42', 'CONSTANTIN 42', 'LISABONA 40', 'TOLETVM 39', 'CORDVBA 39', 'GRANATVM 39', 'SICILIA 37', 'SARTINA 37'.
On the underside of the bottom leaf a crown (the maker's mark) is stamped twice.
- Production date
Height: 14 millimetres
Length: 113 millimetres
Width: 65 millimetres
- Not on display
Latest: 3 (Nov 2016)
4 (Oct 1995) Verdigris on compass needle pivot. String gnomon broken.
- Acquisition date
- Britain, Europe and Prehistory
- Registration number