Quadrant

This term is applied to several objects in use on board a ve el; for instance, a nautical instrument, usually an ebony frame, on the arc of which is a finely graduated ivory scale showing degrees and minutes, with adjustable reflectors etc. its use being to find the altitude of heavenly bodies, angular distances etc. The term is also given to a heavy piece of iron of quadrant shape fitted on a rudder-head to replace the tiller, description of which see page 155.