Proportional compasses consisting of flat legs folding over each other like scissors. The legs are inscribed with two scales to divide a line into equal parts from 2 to 10 and to draw regular polygons from an equilateral triangle to a 17-side figure. The curved steel tips serve to measure the diameters of columns or artillery shot. The hinge, graduated from 10° to 120° with a moving steel index, was used to measure angular apertures. Provenance: Medici collections.