View source for Ligne

{{Short description|Unit of length}}
{{hatnote|For the equivalent English unit, see [[Line (unit)]]. For the Belgian noble house, see [[Ligne family]]. For the tributary of the Sambre, see [[Ligne River]].}}
{{hatnote|Not to be confused with the [[French Line]], a shipping company, or ''[[The French Line]]'', a 1954 musical.}}
{{Infobox unit
| standard = [[Units of measurement in France before the French Revolution|French]]
| quantity = [[length]]
| units1   = French units
| inunits1 = 12 [[Point (typography)#French points|''Truchet point'']]<br /><!--
-->&emsp;{{sfrac|12}} [[Units of measurement in France before the French Revolution#Length|''pouce'']]
| units2   = [[metric system|metric]] ([[SI]]) units
| inunits2 = 2.2558&nbsp;[[millimetre|mm]]
| units3   = [[imperial units|imperial]]/[[US customary units|US]]&nbsp;units
| inunits3 = 0.08881&nbsp;[[inch|in]]
}}
The '''''ligne''''' ({{IPA|fr|liɲ|pron}} ), or '''line''' or '''Paris line''',<ref>{{cite journal |author=Gates, E.J. |year=1915 |title=The Determination of the Limens of Single and Dual Impression by the Method of Constant Stimuli |journal=The American Journal of Psychology |volume=26 |issue=1 |pages=152–157 |jstor=1412884 |doi=10.2307/1412884}}</ref> is a historic unit of length used in France and elsewhere prior to the adoption of the [[metric system]] in the late 18th century, and used in various sciences after that time.<ref>{{cite book |author=Stearn, W.T. |year=1992  |title=Botanical Latin: History, grammar, syntax, terminology and vocabulary, Fourth edition |publisher=David and Charles}}</ref><ref>{{cite journal |author=Neumann, F. |date=January 1863 |title=IX. Experiments on the calorific conductibility of solids |journal=[[Philosophical Magazine]] |series=4 |volume=25 |issue=165 |pages=63&ndash;65 |doi=10.1080/14786446308643418 |url=https://books.google.com/books?id=YIk7AQAAMAAJ&pg=PA63}}</ref> The ''loi du 19 frimaire an VIII'' (Law of 10 December 1799) states that one metre is equal to exactly 443.296 French lines.<ref name=Débarbat>{{cite web
|url = http://www.culture.gouv.fr/culture/actualites/celebrations/metre.htm
|language = French
|title = Fixation de la longueur définitive du mètre
|trans-title=Establishing the definitive metre
|author = Suzanne Débarbat
|publisher = Ministère de la culture et de la communication ([[French language|French]] ministry of culture and communications)
|accessdate = 2011-03-01}}</ref>
It is [[vestigial]]ly retained today by [[France|French]] and [[Switzerland|Swiss]] [[wristwatch|watch]]makers to measure the size of watch casings,<ref name=Swiss>{{citation |title=Foire aux questions sur l'horlogerie et les montres |trans-title=Frequently asked questions about watches and clocks |language=fr |url=http://www.horlogerie-suisse.com/horlomag/articles-horlogers/00199/foire-aux-questions-sur-l-horlogerie-et-les-montres |accessdate=2022-01-18 |website=horlogerie-suisse.com }}</ref>{{efn|{{lang|fr|Par tradition ancestrale, les horlogers n’utilisent pas le millimètre mais la ligne pour désigner le diamètre d'encageage d'un mouvement.}}<ref name=Swiss /> [By ancestral tradition, watchmakers do not use the millimeter but the line to designate the casing diameter of a movement]}}  in button making and in ribbon manufacture.
==Current use==
===Watchmaking===
[[File:BwcOmega911a.jpg|thumb|The ligne is still used by French and Swiss watchmakers]]
There are 12&nbsp;''lignes'' to one [[Units of measurement in France before the French Revolution|French inch (''pouce'')]]. The standardized conversion for a ligne is 2.2558291&nbsp;[[millimetre|mm]] (1&nbsp;mm = 0.443296&nbsp;''ligne''),<ref name=Débarbat /> and it is abbreviated with the letter L or represented by the triple [[Prime (symbol)|prime]], {{char|‴}}.<ref name=Swiss />  One ligne is the equivalent of 0.0888 international [[inch]].
This is comparable in size to the British measurement called "[[line (length)|line]]" (one-twelfth of an [[English units|English]] inch), used prior to 1824.<ref>Oxford English Dictionary</ref> (The French inch at that time was slightly larger than the English one, but the system of 12 inches to a foot and 12 lines to an inch was the same in both cases.)
===Hatmaking===
''Ligne'' is used in measuring the width of ribbons in men's hat bands,<ref>{{Cite web|url=http://www.levinehat.com/blog/2011/08/what-are-french-lignes/|title = What are French Lignes?}}</ref> at 11.26 per international inch.<ref>{{Cite web|url=http://www.levinehat.com/lignes-to-inches-converter|title=Converting between lignes and inches}}</ref>
==Button making==
The [[button]] trade uses the term ''ligne'' (sometimes "line"), but with a substantially different definition: {{convert|1/40|inch|mm|3}}.<ref>{{cite web |title=An Easy Guide to Button Measurement and Sizing |url=https://www.sunmeibutton.com/button-measurement/ |date=2019-06-19 |publisher=Sun Mei Button Enterprise Co., Ltd.}}</ref><ref>{{cite book |title=The Metric System {{!}} Hearings Before a Subcommittee of the Committee on Manufactures, United States Senate, Sixty-seventh Congress, First and Second Sessions on S. 2267 a Bill to Fix the Metric System of Weights and Measures as the Single Standard of Weights and Measures for Certain Uses.|page=216 |date=October 11, 1921 |publisher=By United States. Congress. Senate. Committee on Manufactures}}</ref>
== See also ==
* {{anli|Line (unit)}}
* {{anli|Traditional French units of measurement}}
* {{anli|Horology}}
==Notes==
{{Notelist}}
== References ==
{{reflist}}
[[Category:Obsolete units of measurement]]
[[Category:Units of length]]