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
Yoke (unit of measurement) soils on the Downs one yoke is 231 acres. Yoke (unit of measurement) A yoke was a unit of land measurement used in Kent in England at the time of the Domesday Book for tax purposes. It was equal to a quarter of a sulung. A sulung was the amount of land which could be ploughed by 4 ox-pairs (or approximately 2 hides), therefore a yoke was a pair of oxen, representing the amount of land that could be cultivated by an ox pair. A yoke also described the device used to harness two oxen together (see photo). In early