Astronomical compendium consisting of three hinged brass plates. The outside of the lid bears the Medici coat of arms in relief; the inside carries the tables of the semidiurnal arcs for the months of the year and latitudes 43°45' (Florence) and 43°28' (Pisa). The central plate is engraved with a horary disk. On the bottom is an unfinished circle that was to be used for a windrose. The underside is fitted with a mount for a tripod. Four small feet are placed at the corners. Provenance: Medici collections.