Hair's breadth explained

A hair's breadth, or the width of human hair, is used as an informal unit of a very short length.[1] It connotes "a very small margin" or the narrowest degree in many contexts.[2] [3] [4]

Definitions

This measurement is not precise because human hair varies in diameter, ranging anywhere from 17 μm to 181 μm [millionths of a metre][5] One nominal value often chosen is 75 μm, but this – like other measures based upon such highly variable natural objects, including the barleycorn – is subject to a fair degree of imprecision.

Such measures can be found in many cultures. The English "hair's breadth" has a direct analogue in the formal Burmese system of Long Measure. A "tshan khyee", the smallest unit in the system, is literally a "hair's breadth". 10 "tshan khyee" form a "hnan" (a Sesamum seed), 60 (6 hnan) form a mooyau (a species of grain), and 240 (4 mooyau) form an "atheet" (literally, a "finger's breadth").

Some formal definitions even existed in English. In several systems of English Long Measure, a "hair's breadth" has a formal definition. Samuel Maunder's Treasury of Knowledge and Library of Reference, published in 1855, states that a "hair's breadth" is one 48th of an inch (and thus one 16th of a barleycorn). John Lindley's An introduction to botany, published in 1839, and William Withering' An Arrangement of British Plants, published in 1818, states that a "hair's breadth" is one 12th of a line, which is one 144th of an inch or ~176 μm (a line itself being one 12th of an inch).Carl Linnaeus had earlier recommended, in place of Joseph Pitton de Tournefort's geometric scale for botanical measurements, a scale starting with a "hair's breadth" (Latin: capillus) which was one 12th of a line (Latin: linea), one 6th of a (finger) nail (Latin: unguis), and likewise 144th of a thumb (Latin: pollex); which itself was equal to a (Parisian) inch.

Other body part measurements

Winning a competition, such as a horse race, "by a whisker" (a short beard hair) is a narrower margin of victory than winning "by a nose."[6] [7] An even narrower anatomically-based margin might be described in the idiom "by the skin of my teeth," which is typically applied to a narrow escape from impending disaster. This is roughly analogous to the phrase "as small as the hairs on a gnat's bollock."[8] Some German speakers similarly use “Muggeseggele,” literally “housefly’s scrotum,” as a small unit of measurement.[9]

See also

References

Sources

Further reading

Notes and References

  1. Web site: Hair's breadth (hare's breath) . 10 February 2011 . . January 27, 2015.
  2. Book: Hairs breadth . . https://web.archive.org/web/20150203171433/http://www.oxforddictionaries.com/us/definition/english/a-hair%27s-breadth . dead . February 3, 2015 . January 28, 2015.
  3. Web site: Hairs breadth . . January 27, 2015.
  4. Web site: Hairs breadth . . January 27, 2015.
  5. Web site: Diameter of a human hair. Brian. Ley. 1999. The Physics Factbook. Elert. Glenn. 2018-12-08.
  6. Web site: Win by a nose . January 27, 2015 . The American Heritage® Idioms Dictionary . 2002. Houghton Mifflin Company/Dictionary.com.
  7. Web site: By a nose . Free Dictionary . December 30, 2016.
  8. Web site: The meaning and origin of the expression: By the skin of your teeth . The phrase finder . January 28, 2015.
  9. News: Schönstes schwäbisches Wort: Großer Vorsprung für Schwabens kleinste Einheit . Sellner . Jan . 9 March 2009 . . de . 13 August 2013 . dead . https://web.archive.org/web/20130927133628/http://content.stuttgarter-nachrichten.de/stn/page/1968288_0_9223_schoenstes-schwaebisches-wort-grosser-vorsprung-fuer-schwabens-kleinste-einheit.html . 27 September 2013 .

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