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English units are the historical units of measurement used in England up to 1824, which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications. The units were redefined in the United Kingdom in 1824 by a Weights and Measures Act, which retained many but not all of the unit names and redefined some of the definitions. The term "English units" is ambiguous, as it could refer either to the imperial units used in the UK, or to United States customary units, which retains some unit names but has some different definitions.〔Marks' Standard Handbook for Mechanical Engineers, McGraw Hill, 2006〕 (The terms ''imperial units'' or ''imperial measurements'' are used in the UK to refer to the non-metric system since they were used as a standard throughout the British Empire and the Commonwealth.) ==History== Very little is known of the measurement units of the British Isles prior to Roman colonization in the 1st century CE. During the Roman period, Roman Britain relied on Ancient Roman units of measurement. During the Anglo-Saxon period, the North German foot of 335 millimetres (13.2 inches) was the nominal basis for other units of linear measurement. The foot was divided into 4 palms or 12 thumbs. A cubit was 2 feet, an elne 4 feet. The rod was 15 Anglo-Saxon feet, the furlong 10 rods. An acre was 4 × 40 rods, i.e., 160 square rods or 36,000 square Anglo-Saxon feet. However, Roman units continued to be used in the construction crafts and reckoning by the Roman mile of 5000 feet or 8 stades continued, in contrast to other Germanic countries who adopted the name "mile" for a longer native length closer to the league. From the time of Offa King of Mercia (8th century) until 1526 the ''Saxon pound'', also known as the ''moneyers' pound'' (and later known as the Tower pound) was the fundamental unit of mass measurement. Prior to the enactment of a law known as the "Composition of Yards and Perches" ((ラテン語:Compositio ulnarum et perticarum)) some time between 1266 and 1303, the English system of measurement had been based on that of the Anglo-Saxons, inherited from tribes from northern Germany. The ''Compositio'' retained the Anglo-Saxon rod of 5.03 metres and the acre of 4 × 40 rods. However, it redefined the yard, foot, inch, and barleycorn to of their previous value. Thus, the rod went from 5 old yards to new yards, or 15 old feet to new feet. The furlong went from 600 old feet (200 old yards) to 660 new feet (220 new yards). The acre went from 36,000 old square feet to 43,560 new square feet. Scholars have speculated that the ''Compositio'' may have represented a compromise between two earlier systems of the units, the Anglo-Saxon and the Roman. Contrary to popular belief, the Norman conquest of England had little effect on British weights and measures other than to introduce one new unit: the bushel. William the Conqueror, in one of his first legislative acts, confirmed existing Anglo-Saxon measurement, a position which was consistent with Norman policy in dealing with occupied peoples. Another popular myth is that the Magna Carta of 1215 (specifically chapter 35) had any significant effect on English weights and measures, as this document only mentions one unit (the London Quarter) but does not define it. Later development of the English system continued by defining the units by law and issuing measurement standards. Standards were renewed in 1496, 1588 and 1758. The last ''Imperial Standard Yard'' in bronze was made in 1845; it served as the standard in the United Kingdom until the yard was redefined by the international yard and pound agreement as 0.9144 metre in 1959 (statutory implementation: Weights and Measures Act of 1963). The English system then spread to other parts of the British Empire. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「English units」の詳細全文を読む スポンサード リンク
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