This gunner's quadrant is composed of two flat legs of different lengths, joined at a right angle and connected by a graduated arc. Thanks to a plumb line suspended from a hole in the corner, the arc enabled the gunner (1) to determine the ratio of the calibers of the iron and bronze shot to the required gun elevation, and (2) to measure the gradients of scarp walls in fortifications. Niccolò Tartaglia describes a similar gunner's quadrant in Nova scientia (Venice, 1537). Provenance: Medici collections.