The ''ligne'' ( ), or line or Paris line, is a historic unit of length used in France and elsewhere prior to the adoption of the

metric system The metric system is a system of measurement that succeeded the decimalised system based on the metre that had been introduced in France in the 1790s. The historical development of these systems culminated in the definition of the Interna ...

in the late 18th century, and used in various sciences after that time. The ''loi du 19 frimaire an VIII'' (Law of 10 December 1799) states that one metre is equal to exactly 443.296 French lines. It is

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

ly retained today by French and Swiss

watch A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached b ...

makers to measure the size of watch casings, in button making and in ribbon manufacture.

Current use

Watchmaking

There are 12 ''lignes'' to one French inch (''pouce''). The standardized conversion for a ligne is 2.2558291 mm (1 mm = 0.443296 ''ligne''), and it is abbreviated with the letter L or represented by the triple

prime A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...

, . 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 English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

inch), used prior to 1824. (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, at 11.26 per international inch.

Button making

The

button A button is a fastener that joins two pieces of fabric together by slipping through a loop or by sliding through a buttonhole. In modern clothing and fashion design, buttons are commonly made of plastic but also may be made of metal, wood, o ...

trade uses the term ''ligne'' (sometimes "line"), but with a substantially different definition: .

Notes

References