{{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 = French | quantity = length | units1 = French units | inunits1 = 12 ''Truchet point''<br /><!-- --> {{sfrac|12}} ''pouce'' | units2 = metric (SI) units | inunits2 = 2.2558 mm | units3 = imperial/US units | inunits3 = 0.08881 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=63–65 |doi=10.1080/14786446308643418 |url=https://books.google.com/books?id=YIk7AQAAMAAJ&pg=PA63|url-access=subscription }}</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 |author=Débarbat |first=Suzanne |author-link=Suzanne Débarbat |title=Fixation de la longueur définitive du mètre |trans-title=Establishing the definitive metre |url=http://www.culture.gouv.fr/culture/actualites/celebrations/metre.htm |accessdate=2011-03-01 |publisher=Ministère de la culture et de la communication (French ministry of culture and communications) |language=French}}</ref>
It is vestigially retained today by French and Swiss watchmakers 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 |archive-date=2022-01-21 |archive-url=https://web.archive.org/web/20220121164847/http://www.horlogerie-suisse.com/horlomag/articles-horlogers/00199/foire-aux-questions-sur-l-horlogerie-et-les-montres |url-status=dead }}</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=== thumb|The ligne is still used by French and Swiss watchmakers There are 12 ''lignes'' to one Paris inch ({{lang|fr|pouce}}). The standardized conversion for a ligne is 2.2558291 mm (1 mm = 0.443296 ''ligne''),<ref name=Débarbat /> and it is abbreviated with the letter L or represented by the triple 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" (one-twelfth of an 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? | date=18 April 2015 }}</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:Traditional French units of measurement Category:Units of length