A late 17th-Century German ivory diptych dial,
dated 1687, with a maker's mark for Melchior Karner -- 9.4 x 6cm. (3 11/16 x 2 3/8in.)
FACE Ia, upper leaf, outer face: the central wind rose has sixteen compass points labelled NORT, OST, S[UD] and WEST with a further twelve abbreviated. It is numbered 1-32 beginning at East and has a brass arm-shaped indicator. There is an aperture for compass reading, four small brass feet and two hooks that attach to brass eyes on the back of the lower leaf to secure the dial when open. The corners are decorated with green and red foliage.
FACE Ib, upper leaf, inner face: the pin gnomon dial is labelled at 16-8 and 8-16 in black numerals at the edges to indicate hours of daylight and darkness. Under a red and green sun motif and the title QVANTIAS DIEI, the hour scale is calibrated 1-11 in black numerals and marked with zodical symbols in red. There are five positions for the string gnomon, for latitudes 42°, 45°, 48°, 51° and 54°. Below is a table of latitudes for twenty European cities:
DANTZIG 54° STETIN 54°
LUBECK 54° LITAU 54°
ANTORF 51° LUNDRA 51°
PRAGA 51° COLONIA 51°
PARIS 48° AUGSPURG 48°
NORNBERG 48° WIENN 48°
VENETIA 45° MAILAND 45°
TRENT 45° LEON 45°
ROMA 42° NEAPOLIS 42°
CONSTANTON 42° PORTUGAL 42°
SOLI DEO GLO RIA
FACE IIa, lower leaf, inner face: an inset glazed compass labels the four cardinal points SE, OR, NE, OC and has a blued steel compass needle with brass cap. The horizontal dial has five scales for latitudes 42°, 45°, 48°, 51°, 54° (inner to outer), labelled 4-12, 1-8 in black numerals on the outermost scale, with stars to indicate half-hours. A pin gnomon indicates Italian hours labelled 10-23 in black and Babylonian hours labelled 1-14 in red. The initials M K are punched above the date 1687, with some red and green floral decoration, and two brass hooks for nails on the front of the upper leaf.
FACE IIb, lower leaf, outer face: bears a standard German lunar scale with a stamped brass volvelle. The man-in-the-moon motif on the volvelle is graduated 1-12 (x2); the inner hour scale is graduated 1-12 (x2); and the calendar scale is labelled 1-29. The Epact scales (beginning with 23 and 13 respectively for the year 1687) around the volvelle are labelled EPACTA GREGORI ANNO and EPACTA IVLIANA ANNO 1687, with red and green foliate decorations and four small brass bun feet.