Hair's breadth

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

Scanning electron microscope image of a human hair

Definitions

This measurement is not precise because human hair varies in diameter, ranging anywhere from 17 μm to 181 μm [millionths of a metre] One nominal value often chosen is 75 micrometres (0.0030 in), 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" (capillus) which was one 12th of a line (linea), one 6th of a (finger) nail (unguis), and likewise 144th of a thumb (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." 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." Some German speakers similarly use “Muggeseggele,” literally “housefly’s scrotum,” as a small unit of measurement.

See also

• Beard-second
• List of humorous units of measurement
• List of unusual units of measurement
• Indefinite and fictitious numbers

References

Sources

• Boaz, James (1823-03-21). "On a fixed Unit of Measure". In Tilloch, Alexander; Taylor, Richard (eds.). Philosophical Magazine. Vol. 61. London: Richard Taylor. pp. 266–269.
• Carey, Felix (1814). "Of Weights &c.". A grammar of the Burman language. Mission Press/Internet Archive. p. 209.
• Crook, John; Osmaston, Henry (1994). "Weights and Measures". Himalayan Buddhist Villages. Delhi: Shri Jainendra Press. p. 133. ISBN 978-0-86292-386-0.
• Johnson, Cuthbert William (1842). "Weights and Measures". The farmer's encyclopædia, and dictionary of rural affairs. London: Longman, Orme, Brown, Green, & Longmans/Internet Archive. p. 1257.
• Latter, Thomas (1991). "Measures". A Grammar of the Language of Burmah (republished ed.). Asian Educational Services. p. 167. ISBN 978-81-206-0693-7.
• Lindley, John (1839). "Glossology". An introduction to botany (3rd ed.). London: Longman, Orme, Brown, Green, & Longmans. p. 474.
• Maunder, Samuel (1855). "Measures of Length". Treasury of Knowledge and Library of Reference. New York: J. W. Bell. p. 12.
• Milne, Colin (1805). "Mensura". A Botanical Dictionary: Or, Elements of Systematic and Philosophical Botany (3rd ed.). London: H.D. Symonds.
• Smith, Graham T. (2002). Industrial metrology. Springer. pp. 253. ISBN 978-1-85233-507-6.
• Withering, William (1818). "Botanical Terms". An Arrangement of British Plants. Vol. 1 (6th ed.). London: Longman & Co., Robert Scholey, et al. p. 69.

Further reading

• Dalzell, Tom; Victor, Terry, eds. (2013). The New Partridge Dictionary of Slang and Unconventional English. Routledge, Taylor & Francis Group. p. 1843. ISBN 978-1-317-37252-3.
• Dickson, Paul (1994). War Slang: Fighting Words and Phrases of Americans from the Civil War to the Gulf War. Ann Arbor: University of Michigan Press. p. 286. ISBN 0-671-75022-4.
• Dickson, Paul (April 11, 2011). War Slang: American Fighting Words & Phrases Since the Civil War. Courier Corporation. p. 286. ISBN 978-0-486-47750-3.
• Dorson, Richard Mercer (1986). Handbook of American Folklore. Bloomington, Indiana: Indiana University Press. p. 123. ISBN 0-253-20373-2.
• Hales, John (2005). Shooting Polaris a personal survey in the American West. Columbia, Missouri: University of Missouri Press. p. 45. ISBN 0-8262-1616-1.
• Jillette, Pen (2004). Sock: A Novel. St. Martin's Publishing. p. 114. ISBN 1-4299-6131-7.
• Johnson, Sterling (1995). English as a Second f*cking Language. New York: Saint Martin's Press, St. Martin's Griffin. ISBN 978-0-312-14329-9.
• McYoung, Mark Animal (1991). Fists, Wits and a Wicked Right:Surviving on the Wild Side of the Street. Boulder, Colorado: Paladin Press. p. 25.
• Michaelis, David (1983). The best of friends: profiles of extraordinary friendships (Print). New York: Morrow. p. 231. ISBN 0-688-01558-1.
• Morton, Mark S. (2003). The lover's tongue a merry romp through the language of love and sex (Print). Toronto Ontario: Insomniac Press. p. 134. ISBN 1-894663-51-9.
• Partridge, Eric; Dalzell, Tom; Victor, Terry (2008). The Concise New Partridge Dictionary of Slang and Unconventional English (Print). London New York: Routledge. pp. 535, 1596 & 1601. ISBN 978-0-415-21259-5.
• Raudaskoski, Heikki (January 1997). "'The Feathery Rilke Mustaches and Porky Pig Tattoo on Stomach': High and Low Pressures in Gravity's Rainbow". Postmodern Culture. 7 (2). doi:10.1353/pmc.1997.0007. Retrieved January 20, 2015.
• Spelvin, Georgina (2008). The Devil Made Me Do It (Print). Los Angeles, California: Lulu.com, Little Red Hen Books. p. 110. ISBN 978-0-615-19907-8.