Triangulation instrument consisting of two long rectangular-section legs with pointed ends and a graduated semicircle. The legs are inscribed on the front with the scale for dividing a line into as many as 12 equal parts, and with the polygon scale for constructing figures with up to 24 sides. The verso carries a scale divided into 360 equal parts. The semicircle has, on the front, a set of hour lines, and on the back, a scale of metals, a degree scale, and a shadow square divided into six parts per side. The instrument is kept in a case decorated with studs and mask figures. The accessories include: a gimbaled compass (incomplete), a small quadrant divided into 90 degrees and equipped with a cursor, a gunner's level with two quadrants and two plumb bobs, a brass plumb bob, a viewer, a pointed cursor, and a rectangular cover with a point. The instrument is signed by Paolo Massucci. Provenance: Medici collections.