Dagger-Dividers-Quadrant

During the Renaissance, an emerging class of professional military engineers, architects, and master gunners invented complex combination weapon-tools as intellectual exercises. The design of this dagger-divider-quadrant merged science and technology with craft and aesthetics. When closed, this tool could be used as a dagger for self-defense or as a ruler to measure the interior diameter of a cannon barrel for sizing projectiles. When unfolded (as shown), a plumb bob falls, forming part of a quadrant used for both leveling artillery and measuring distances.