Book Dial (16th Century)
Ivory, glass, iron, pewter, string
Late 16th century, Germany
The angle formed by the dial’s cover and base allows a central string connecting them to cast shadows that mark the time at 48 degrees latitude. The compass serves to orient the dial north and south, and the lines marked on the base and cover indicate the shadow direction for each hour.
AMNH Hayden Planetarium Collection 2000