Editing Chain (unit) (section)

=== Engineer's chain (Ramsden's chain)===
{{anchor|Ramsden's chain (engineer's chain)}}
{{main|Ramsden surveying instruments#Chains and rods}}
A longer chain of {{convert|100|ft|m|1}}, with a hundred {{convert|1|ft|mm|0}} links, was devised in the UK in the late 18th century by [[Ramsden surveying instruments|Jesse Ramsden]], though it never supplanted Gunter's chain.<ref name=Rankine>{{cite book |author1=William John Macquorn Rankine |author-link=William John Macquorn Rankine |title=A Manual of Civil Engineering |date=1863 |publisher=Griffin Bohn & Company |location=London |pages=[https://archive.org/details/amanualcivileng05rankgoog/page/n38 18]–19 |edition=2nd |url= https://archive.org/details/amanualcivileng05rankgoog}}</ref> Surveyors also sometimes used such a device, and called it the ''engineer's chain''.<!-- The term ''chain'' in this case usually refers to the measuring instrument rather than a unit of length, and distances measured are normally given in feet and decimal fractions of a foot (not inches).{{citation needed|date=July 2018}} A lot of these references refer to the manufacturing process used to increase the accuracy of an existing precision instrument- you had to solve heat expansion, twisting, and wear from friction. Also important was the design of the handle and whether it incorporated an adjustment screw. This is mainly supported by Rankine. The Rankine ref does not mention Ramsden- so thats another factoid to remove. Look to [[Anglo-French Survey (1784–1790)]] for a better reference. Indeed [[Gunter's chain#Similar measuring chains]] will be a useful starting point when it has been verified- for example Ramsden was British not American. See also:

[http://www.clintoncountyohgis.org/units_of_measure.htm Clinton is one of the many sites that copies from US government Glossary of Surveying and Mapping Terms]
[http://www.cdscapes.com/reading-property-surveys.html Charlotte dreamspace is another]-->