Chain

Chain, in Surveying (called Gunter's Chain, from its inventor, Edmund Gunter, q.v.), is a measure of 22 yards long, composed of 100 iron links, each of which is thus 7.92 inches long. As an acre contains 4840 square yards, 10 square chains ($22\; \backslash times\; 22\; \backslash times\; 10\; =\; 4840$ square yards) or 100,000 square links make an acre.