Weights and measures

Weights and measures, units of weight, length, area, and volume commonly used in the home, in commerce, and in industry. Although, like other early peoples, the Hebrews used measures such as the foot, the cubit (the length of the human forearm), and the span, which could easily be realized in practice by using parts of the body, in commerce they also used standard containers and weights. Later, weights were based on the quantity of precious metal in coins. During and after the Middle Ages each region evolved its own system of weights and measures. In the 19th century these were standardized on a national basis, and then in turn were superseded by standards of the metric system. In the Western world, only the British Empire and the United States retained their own systems (the Imperial System and the U.S. Customary System, respectively) into the mid-20th century. With the United Kingdom's adoption of the International System of Units (Sl units), the United States remains one of the few countries that does not use metric units, although, as has been the case since 1959, the U.S. customary units are now defined in terms of their metric counterparts and not on the basis of independent standards. In the United States the administration of weights and measures is coordinated by the National Bureau of Standards.