In the context of surveying a chain is a unit of measurement having a distance of 66 feet. The Gunter’s Chain was designed and introduced in 1620 by English mathematician, Edmund Gunter. It was comprised of 100 connected links having a total length of 66 feet. The chain became the statutory measure in the British Empire.
Even today with feet and metres replacing the chain as units of measurement, the term chaining is still used by surveyors in measuring distances.
Although the Gunter’s chain was replaced by steel band tapes at the beginning of the 10th century for most survey work today many distances and areas are based on the chain. To name a few: one mile equals 80 chains, one acre equals 10 square chains and one furlong (used in horse racing) equals 10 chains.
Chain, Gunter’s
Chain, Engineer’s