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2021-01-11 16:57:35
Offset staff].
c1850. Surveyor's offset staff Mahogany staff (4 feet 9 inches) with steel shod pointed foot, the pole 1 inch dia., 4 inch dia. hard ball. 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.
Bookseller: Daniel Crouch Rare Books LLP [London, United Kingdom]
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