jacob's staff

The Sailor's Word-Book

, or cross-staff.


A mathematical instrument to take altitudes, consisting of a brass circle, divided into four equal parts by two lines cutting each other in the centre; at each extremity of either line is fixed a sight perpendicularly over the lines, with holes below each slit for the better discovery of distant objects. The cross is mounted on a staff or stand for use. Sometimes, instead of four sights, there are eight.

Related Words