A foot (plural: feet; abbreviation or symbol: ft or ′ (the prime symbol)) is a unit of length. Since 1960 the term has usually referred to the international foot, defined as being one third of a yard, making it 0.3048 meters exactly. It is an integral part of both the imperial and United States customary systems of units. The foot is subdivided into 12 inches.
Historically the foot, which was used in Ancient Greece, Ancient Rome, England, Scotland and many Continental European countries and which varied from country to country and in some cases from city to city, was a partly local systems of units. Its length was usually between 250 mm and 335 mm and was generally, but not always, subdivided into 12 inches or 16 digits.
Historically the human body has been used to provide the basis for units of length. The foot of a white male is typically about 15.3% of his height, giving a person of 160 cm (5 ft 3 in) a foot of 245 mm and one of 180 cm (5 ft 11 in) a foot of 275 mm. These figures are less than the foot used in most cities over time, suggesting that the "foot" was actually a synonym for a "shoe".
The Greek foot (ποὐς,pous) had a length of 1/600 of a stadion, one stadion being about 181.2 m, therefore a foot being at the time about 302 mm. Its exact size varied from city to city and could range as much as between 270 mm and 350 mm, but lengths used for temple construction appear to have been about 295 mm to 325 mm, the former being close to the size of the Roman foot.
The standard Roman foot (pes) was normally about 295.7 mm, but in the provinces, the pes Drusianus (foot of Nero Claudius Drusus) with a length of about 334 mm was used. (In reality, this foot predated Drusus).
Originally both the Greeks and the Romans subdivided the foot into 16 digits, but in later years, the Romans also subdivided the foot into 12 unciae (from which both the English words "inch" and "ounce" are derived).
After the fall of the Roman Empire, some Roman traditions were continued but others fell into disuse. In 790 CE Charlemagne attempted to reform the units of measure in his domains. His units of length were based on the toise and in particular the toise de l'Écritoire, the distance between the fingertips of the outstretched arms of a man. The toise has 6 pied (feet) each of 326.6 mm (12.86 in).
He was unsuccessful in introducing a standard unit of length throughout his realm: an analysis of the measurements of Charlieu Abbey shows that during the 9th century the Roman foot of 296.1 mm was used; when it was rebuilt in the 10th century, a foot of about 320 mm[Note 1] was used. At the same time, monastic buildings used the Carolignian foot of 340 mm.[Note 1]
The procedure for verification of the foot as described in the 16th century by Jacob Koebel in his book Geometrei. Von künstlichem Feldmessen und absehen is:
Stand at the door of a church on a Sunday and bid 16 men to stop, tall ones and small ones, as they happen to pass out when the service is finished; then make them put their left feet one behind the other, and the length thus obtained shall be a right and lawful rood to measure and survey the land with, and the 16th part of it shall be the right and lawful foot.
The Roman foot was introduced to Britain in the 1st century CE. The length of the Roman foot has been estimated at 296 mm or 11.65 inches. In the 5th century, the Anglo-Saxons introduced the North German foot of 335 mm (13.2 inches). The new foot was used for land measurement, while the Roman foot continued to be used in the construction crafts. Some time between 1266 and 1303 the weights and measures of England were radically revised by a law known as the Composition of Yards and Perches (Compositio ulnarum et perticarum) often known as the Compositio for short. This law, attributed to either Henry III or his successor Edward I, instituted a new foot that was exactly 10/11 the length of the old foot, with corresponding reductions in the size of the yard, ell, inch, and barleycorn. Miles, furlongs and rods, however, remained the same. The furlong remained an eighth of a mile, but changed from 600 old feet to 660 new feet. The rod remained the same length, but changed from 15 old feet to 16.5 new feet.
Ordinatum est, quod tria grana ordei sicca et rotunda faciunt pollicem, duodecim pollices faciunt pedem, tres pedes faciunt ulnam, quinque ulnae et dimidia faciunt perticam, et quadraginta perticae in longitudine et quatuor in latitudine faciunt unam acram. — Compositio ulnarum et perticarum
"It is ordained that three dry round grains of barley make an inch, 12 inches make a foot, three feet make a yard, five yards and a half make a perch, and 40 perches in length and four in breadth make one acre."
- ↑ Oswald Ashton Wentworth Dilke (May 22, 1987). Mathematics and measurement. University of California Press. p. 23. ISBN 978-0-520-06072-2. http://books.google.com/books?id=AKJZvXOS7n4C&pg=PA26. Retrieved February 2, 2012.
- ↑ Fessler, Daniel M; Haley, Kevin J; Lal, Roshni D (January–February 2005). "Sexual dimorphism in foot length proportionate to stature". Annals of Human Biology, 32 (1): 44–59. http://www.sscnet.ucla.edu/anthro/faculty/fessler/pubs/AHBFootSizeDimorphism.pdf.
- ↑ http://archive.org/stream/historyofherod02hero/historyofherod02hero_djvu.txt , book II ,6.7
- ↑ http://www.perseus.tufts.edu/hopper/artifact?name=Epidauros%2C+Stadium&object=Building
- ↑ Oswald Ashton Wentworth Dilke (May 22, 1987). Mathematics and measurement. University of California Press. p. 26. ISBN 978-0-520-06072-2. http://books.google.com/books?id=AKJZvXOS7n4C&pg=PA26. Retrieved February 2, 2012.
- ↑ Russ Rowlett. "How Many? A Dictionary of Units of Measurement". Center for Mathematics and Science Education, University of North Carolina at Chapel Hill. http://www.unc.edu/~rowlett/units/dictT.html. Retrieved February 28, 2011.
- ↑ Sutherland, Elizabeth R (May 1957). "Feet and dates at Charlieu". Journal of the Society of Architectural Historians 16 (2).
- ↑ Jacob Koebel (16th century) (in German). Geometrei. Von künstlichem Feldmessen und absehen. http://www.robweir.com/blog/2007/12/right-and-lawful-rood.html.
- ↑ Great Britain (1762). The statutes at large: from the Magna Charta, to the end of the eleventh Parliament of Great Britain, anno 1761 (continued to 1807). The statutes at large. 1. Printed by J. Bentham. p. 400. http://books.google.com/books?id=iPQuAAAAIAAJ&pg=PA400&dq=Compositio+ulnarum+et+perticarum#v=onepage&q=Compositio%20ulnarum%20et%20perticarum&f=false. Retrieved November 30, 2011.
- ↑ Zupko, Ronald Edward (1977). British Weights and Measures: A History from Antiquity to the Seventeenth Century. University of Wisconsin Press. pp. 6, 10, 20. ISBN 978-0-299-07340-4. http://books.google.com/books?id=pWUgAQAAIAAJ&dq=zupko&q=millimeters#search_anchor.
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