This box-shaped, finely chiseled German dial carries on the outer side of the lid a geographic mirror of the northern hemisphere. The inner side carries a revolving disk giving the Sun's position over a division corresponding to the lunar month. Inside the box are the equinoctial circle for the daytime hours with an index, an index arm, and an arc graduated for different latitudes. At the bottom of the box are a windrose, an opening with a compass for orienting the instrument (the magnetic needle is missing), and another revolving windrose. The outer side of the bottom carries a geographic mirror of the southern hemisphere, a circumference divided into degrees and days of the year, and a revolving disk with index arm and index for the positions of the Moon. Provenance: Vincenzo Viviani bequest.