Earth's circumference mile in the seventeenth century and the metre in the eighteenth. Earth's polar circumference is almost exactly 40,000 km because the metre was originally calibrated on this measurement (1/10-millionth of the distance between the poles and the equator), which is almost exactly 21,600 nautical miles (being defined as one minute of a degree – i.e. 360 multiplied by 60). It has been described as "the single most important measurement" of the Earth, assuming the Earth to be a sphere (the Earth is an technically an ellipsoid, albeit with just 0.3% flattening). Earth's circumference lines are the foundation of the coordinate
Units of measurement in France a sound basis for a system of measurement. Under the "décret impérial du 12 février 1812" (imperial decree of 12 February 1812), he introduced a revised system of measure – the "mesures uselles" or "customary measures" for use in small retail businesses. However, all government, legal and similar works still had to use the metric system and the metric system continued to be taught at all levels of education. The names of many pre-metric units were reintroduced, but were redefined in terms of metric units. Thus the "toise" (fathom) was defined as being two metres with six "pied" (feet) making