Jacob's Staff
a pilgrim's staff, so designated from the pilgrimages made to the Shrine of St. James at Compostella in Spain. Also a staff containing a concealed dagger. In surveying, an instrument for taking altitudes, having a brass circle divided into four equal parts by two extremity is diametric lines. At each ext a perpendicular riglet over the lines, with objects. The cross is mounted on a staff.
Also an instrument used to measure distances and heights. Also a straight rod tances and heights. Also a straight rod and pintle at the summit for supporting