- 发布日期: c1850.
- 物理描述: Mahogany staff (4 feet 9 inches) with steel shod pointed foot, the pole 1 inch dia., 4 inch dia. hard ball.
- 库存参考: 15107
A finely made example of an offset staff. The instrument consists of a turned wooden pole. At one end is a metal spike so that the pole can be easily driven into the ground. On the other end is a wooden ball with a cross-slight. The instrument was designed to measure off sets, that is, to locate objects that are at a 90 degree angle to the surveying centreline.