细节
AN IVORY AND SILVER DIPTYCH DIAL
FLEMISH, 1590
leaf 1a silver nocturnal volvelle engraved to folding arm VRSA MAIOR the silver disc with inner equatorial hours scale, the side with latitude scale 0-90°, foliage and scroll decoration to corners.
leaf 1b dated 1590 with silver volvelle for age of the Moon and planetary aspects.
leaf 2a bearing compass bowl with 16-point painted card compass rose, horitzontal dial 4-12-8.
leaf 2b with latitude table for twelve cities.
2¾in. (7cm.)