Editing Chain (unit) (section)

==Definition==
The UK statute chain is 22 yards, which is {{convert|66|feet|4}}. This unit is a [[statute measure]] in the United Kingdom, defined in the [[Weights and Measures Act 1985]].<ref name=1985Act>
{{Cite web |title=Weights and Measures Act 1985 |url=http://www.legislation.gov.uk/ukpga/1985/72/schedule/1/part/VI |website=Legislation.gov.uk |access-date=25 September 2014 |at=Sch 1, Part VI }}</ref> One link is a hundredth part of a chain, which is {{convert| 7.92|inch|cm|4}}.<ref name=Rankine/>

The surveyor's chain first appears in an illustration in a Dutch map of 1607,<ref name="map">{{cite web |last1=Corneliisz van Alckmaer |first1=Pieter |title="Caerte vande gheleghentheyt van de Beemster met de landen die daeromme ende aengheleghen zijn, na rechte landmetersch conste op perfecte maet aldus ghestelt door Pieter Cornelisz. Cort van Alckmaer, ghesworen landmeter, anno 1607". Het Schermereiland met links een deel van de onbedijkte Schermer en rechts de onbedijkte Beemster. |url=https://www.regionaalarchiefalkmaar.nl/collecties/beelden/beelden-2/detail/9a5bede0-ce28-4584-9494-06c0abef1af9 |website=Regional Archive, Alkmaar |access-date=29 July 2018 |language=nl}}</ref> and in an English book for surveyors of 1610.<ref>{{cite encyclopedia |encyclopedia=Oxford English Dictionary |date=1933 |entry=Chain (5) |volume=2 |page=248 |url=https://archive.org/details/the-oxford-english-dictionary-1933-all-volumes/The%20Oxford%20English%20Dictionary%20Volume%202/page/248/mode/1up |quote=1610 W. F{{sc|olkingham}}, ''Art Survey.'' |title=The Oxford English Dictionary - 1933 - All Volumes }}</ref> In 1593 the [[Mile#English mile|English mile]] was redefined by a statute of [[Queen Elizabeth I]] as 5,280 feet, to tie in with [[Composition of Yards and Perches|agricultural practice]]. In 1620, the [[polymath]] [[Edmund Gunter]] developed a method of accurately surveying land using a surveyor's chain 66&nbsp;feet long with 100 links.<ref>{{cite web |title=Gunter biography |url=http://www-history.mcs.st-andrews.ac.uk/Biographies/Gunter.html |website=www-history.mcs.st-andrews.ac.uk |access-date=21 July 2018}}</ref> The 66-foot unit, which was four perches or rods,<ref name="Slater&Saunders">{{cite web |last1=Slater |first1=Michael |last2=Saunders |first2=Ian |title=Rods, poles and perches |url=http://www.northcravenheritage.org.uk/nchtjournal/Journals/2006/RodsPolesPerches/RodsPolesPerches.html |website=www.northcravenheritage.org.uk |publisher=North Craven Heritage Journal |access-date=29 July 2018}}</ref> took on the name the chain. By 1675 it was accepted, and [[John Ogilby|Ogilby]] wrote:
{{blockquote|
...a Word or two of Dimensurators or Measuring Instruments, whereof the most usual has been the Chain, and the common length for English Measures 4 Poles, as answering indifferently to the English Mile and Acre, 10 such Chains in length making a Furlong, and 10 single square Chains an Acre, so that a square Mile contains 640 square Acres...'<ref>{{cite book |title=Britannia  |chapter=Preface |chapter-url=https://www.fulltable.com/vts/m/map/ogilby/a/SH947.jpg |date=1675 |via=Fulltable.com}}</ref> |source=John Ogilby, ''[[Britannia (atlas)|Britannia]]'', 1675}}

From [[Gunter's chain|Gunter's system]], the chain and the [[Link (unit)|link]] became standard surveyors' units of length and crossed to the colonies. The thirteen states of America were expanding westward and the public land had to be surveyed for a [[cadastral]]. In 1784 [[Thomas Jefferson]] wrote a report for the [[Continental Congress]] proposing the [[Land Ordinance of 1785#History|rectangular survey system]]; it was adopted with some changes as the [[Land Ordinance of 1785]] on 20 May the following year. In the report, the use of the chain as a unit of measurement was mandated, and the chain was defined.<ref name="Cazier">{{cite web |last1=Cazier |first1=Lola |title=Surveys and Surveyors of the Public Domain 1785-1975 |url=https://www.ntc.blm.gov/krc/uploads/538/Sur_Sur_Pub_Dom.pdf |publisher=US Government |access-date=29 July 2018 |id=Stock Number 024-041-00083-6 |page=22}}</ref> 
<!-- This is a verbatim quote. Please do not "improve" by inserting other sources --> {{blockquote|1=
The chain is the unit of linear measurement for the survey of the public lands as prescribed by law. All returns of measurement in the rectangular system are made in the true horizontal distance in links, chains, and miles. The only exceptions to this rule are special requirements for measurement in feet in mineral surveys and townsite surveys.<ref name="Cazier" />

Linear Measurement
:1 Chain = 100 links or 66 feet
:1 Mile = 80 chains or 5,280 feet

Area Measurement
:1 Acre = 10 square chains or 43,560 square feet
:1 square mile = 640 acres
|source = Lola Cazier (1976), ''Surveys and Surveyors of the Public Domain 1785-1975'', page 15}}
<!-- Above is a verbatim quote. Please do not "improve" by inserting other sources -->

<!-- still we don't have a source that definitive says that: Gunter took the existing chain and modified it so it had 100 links measuring 4 perches in total so that it was 1/10 of a furlong, and tied the that to the existing acre measure. We don't know what his invention was – and there is no causal link between the instrument and the unit that appears to have been named after it-- help please if you have access to a hidden JSTOR PhD.b -->