Editing Calibration (section)

===Calibration of weights and distances ({{circa|lk=no|1100 CE}})===
{{see also|Weights and Measures Act}}

[[Image:Avery postal scale.JPG|thumb|upright|right|An example of a [[weighing scale]] with a {{frac|1|2}} ounce calibration error at zero. This is a "zeroing error" which is inherently indicated, and can normally be adjusted by the user, but may be due to the string and rubber band in this case]]
Early measurement devices were ''direct'', i.e. they had the same units as the quantity being measured. Examples include length using a yardstick and mass using a weighing scale. At the beginning of the twelfth century, during the reign of Henry I (1100-1135), it was decreed that a yard be "the distance from the tip of the King's nose to the end of his outstretched thumb."<ref name="Ackroyd2012">{{cite book|last=Ackroyd|first=Peter|title=Foundation: The History of England from Its Earliest Beginnings to the Tudors|url=https://books.google.com/books?id=Z2XHs80O0OEC&pg=PT133|date=16 October 2012|publisher=St. Martin's Press|isbn=978-1-250-01367-5|pages=133–134}}</ref> However, it wasn't until the reign of Richard I (1197) that we find documented evidence.<ref name="BlandTawney1919">{{cite book|last1=Bland|first1=Alfred Edward|last2=Tawney|first2=Richard Henry|title=English Economic History: Select Documents|url=https://archive.org/details/ajc0024.0001.001.umich.edu|year=1919|publisher=Macmillan Company|pages=[https://archive.org/details/ajc0024.0001.001.umich.edu/page/154 154]–155}}</ref>
:''Assize of Measures''
:"Throughout the realm there shall be the same yard of the same size and it should be of iron."

Other standardization attempts followed, such as the [[Magna Carta]] (1225) for liquid measures, until the [[Mètre des Archives]] from France and the establishment of the [[Metric system]].