The line (abbreviated L or l or ‴ or lin.) was a small

English unit English units are the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at d ...

of length, variously reckoned as , , , or of an inch. It was not included among the units authorized as the British

Imperial system The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed th ...

in 1824.

Size

The line was not recognized by any statute of the

English Parliament The Parliament of England was the legislature of the Kingdom of England from the 13th century until 1707 when it was replaced by the Parliament of Great Britain. Parliament evolved from the great council of bishops and peers that advised t ...

but was usually understood as of a barleycorn, which itself was recognized by statute as of an inch. The line was eventually decimalized as of an inch, without recourse to barleycorns. The US

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 same or a similar term but defined as one-fortieth of the US-customary inch (making a button-maker's line equal to 0.635 mm).

In use

Botanists This is a list of botanists who have Wikipedia articles, in alphabetical order by surname. The List of botanists by author abbreviation is mostly a list of plant taxonomists because an author receives a standard abbreviation only when that auth ...

formerly used the units (usually as inch) to measure the size of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

parts. Linnaeus's ''Philosophia botanica'' (1751) includes the Linea in its summary of units of measurements, defining it as "Linea una Mensurae parisinae"; Stearns gives its length as 2.25 mm. Even after

metrication Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, countries have transitioned from local and traditional units of measurement to the metric system. This process began in ...

, British botanists continued to employ tools with gradations marked as ''linea'' (lines); the British line is approx. 2.1 mm and the Paris line approx. 2.3 mm. Entomologists, both in the UK and in other European countries, in the 1800s were using lines as a unit of measurement for insects, at least for the relatively large mantids and phasmids - examples include Westwood, in the UK, and de Haan in the Netherlands. Gunsmiths and armament companies also employed the -inch line (the "decimal line"), in part owing to the importance of the German and

Russian Russian(s) refers to anything related to Russia, including: *Russians (, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *Rossiyane (), Russian language term for all citizens and peo ...

arms industries. These are now given in terms of

millimeter 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, -er, ...

s, but the seemingly arbitrary

7.62 mm caliber The 7.62 mm caliber is a nominal caliber used for a number of different cartridges. Historically, this class of cartridge was commonly known as .30 caliber, the imperial unit and customary unit equivalent, and was most commonly used for ...

was originally understood as a 3-line caliber (as with the 1891 Mosin–Nagant rifle). The 12.7 mm caliber used by the M2 Browning machine gun was similarly a 5-line caliber.

Foreign units

Other similar small units called lines include: * The

' (ли́ния), of the ''diuym'' which had been set precisely equal to an English inch by Peter the Great * The French ' or "Paris line", of the French inch (''french: pouce''), 2.256 mm and about 1.06 L. * The

Portuguese Portuguese may refer to: * anything of, from, or related to the country and nation of Portugal ** Portuguese cuisine, traditional foods ** Portuguese language, a Romance language *** Portuguese dialects, variants of the Portuguese language ** Portu ...

', of the Portuguese inch or 12 "points" (') or 2.29 mm * The German ' was usually of the German inch but sometimes also German inch * The Vienna line, of a Vienna inch. Karl Wilhelm Naegeli; Simon Schwendener
"The Microscope in Theory and Practice"
p. 294.

References

Citations

Bibliography