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The Imperial system is a 19th century British invention made necessary by the loss of their standards in the fire that destroyed the Houses of Parliament in 1834. They relabeled the traditional yard and avoirdupois pound as "Imperial" (how typical of them), and created new decimalized versions of the gallon and bushel to compete with the godless French. These new units (and their subdivisions) are quite different from the ones that continue to be used in the U.S.
