This gunner's quadrant is composed of two flat legs of uneven length, joined at a right angle, and a graduated semi-circle. The longer leg has a sliding viewer. The plumb bob, now missing, enabled the instrument to be used to measure heights, distances, scarp-wall gradients, and gun elevations. A gunner's quadrant similar to this described by Niccolò Tartaglia in Nova scientia (Venice, 1537). Provenance: Medici collections.