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A vernier scale is a device that lets the user measure more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale. It is a scale that indicates where the measurement lies in between two of the marks on the main scale. Verniers are common on sextants used in navigation, scientific instruments used to conduct experiments, machinists' measuring tools (all sorts, but especially calipers and micrometers) used to work materials to fine tolerances, and on theodolites used in surveying. ==History== Calipers without a vernier scale originated in ancient China as early as the Xin dynasty (9 AD).〔. An abridged version.〕〔(【引用サイトリンク】title=Bronze Caliper of the Wang Mang Regime )〕 The secondary scale, which contributed extra precision, was invented in 1631 by French mathematician Pierre Vernier (1580–1637). Its use was described in detail in English in ''Navigatio Britannica'' (1750) by mathematician and historian John Barrow.〔Barrow called the device a Vernier scale. See: John Barrow, ''Navigatio britannica: or a complete system of navigation'' … (London, England: W. and J. Mount and T. Page, 1750), (pp. 140–142 ), especially page 142.〕 While calipers are the most typical use of Vernier scales today, they were originally developed for angle-measuring instruments such as astronomical quadrants. In some languages, the Vernier scale is called a nonius. It was also commonly called a nonius in English until the end of the 18th century.〔 ''Nonius'' is the Latin name of the Portuguese astronomer and mathematician Pedro Nunes (1502–1578), who in 1542 invented a different system for taking fine angular measurements. Nunes' nonius was not widely adopted, being difficult to make and also difficult to read. Tycho Brahe used it on at least one instrument.〔Daumas, Maurice, ''Scientific Instruments of the Seventeenth and Eighteenth Centuries and Their Makers'', Portman Books, London 1989 ISBN 978-0-7134-0727-3〕〔(1911 Encyclopaedia Britannica article on Navigation ). Accessed April 2008〕 The name "vernier" was popularised by the French astronomer Jérôme Lalande (1732–1807) through his ''Traité d'astronomie'' (2 vols) (1764).〔Lalande, Jérôme (1746), ''Astronomie'', vol. 2 (Paris, France: Desaint & Saillant), (pages 859-860 ).〕 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「Vernier scale」の詳細全文を読む スポンサード リンク
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