F. W. Simms in England noted in 1836 that the recent construction of canals and railroads had led to the introduction of a chain in which each link and its associated rings was 12 inches long. Chains of this sort, measuring either 50 or 100 feet overall, were soon known as engineer's
chains. This example was sold by Keuffel & Esser in New York. It has 100 links made of No. 12
steel, brass handles and tallies, and measures 100 feet overall. The links and rings are brazed shut. There is a spring hook (snap) at 50 feet, so that the surveyor can separate the chain into two equal
halves. New, it cost $11. The United States Geological Survey transferred it to the Smithsonian in 1907.
Ref: Keuffel & Esser, Catalogue (New York, 1906), p. 505.
F. W. Simms, A Treatise on the Principal Mathematical Instruments (Baltimore, 1836), p. 10.