Surveying compass consisting of a circular plate whose circumference carries a degree scale divided into eight 45° sectors. At the center is the windrose, containing a compass complete with glass and magnetic needle. Around the compass rotates the diopter with sights, at whose ends is attached a half-square circumscribing the main disk. There is a cardboard case, with iron reinforcements and a wooden lining, divided into three compartments. Provenance: Medici collections.