Volume Imperial volume units, illustrated as jugs of various sizes. Note: *The square rod has been called a pole or perch or, more properly, square pole or square perch for centuries. The rod is also called pole or perch and equal to 5 + 1⁄ 2 yardsĪrea Table of area units and equivalents Gunter's survey units (17th century onwards)ġ⁄ 100 of a chain and 1⁄ 1000 of a furlong Until the adoption of the international definition of 1852 m in 1970, the British nautical (Admiralty) mile was defined as 6080 ft. Used for measuring distances at sea (and also in aviation) and approximately equal to one arc minute of a great circle.
Equal to 100 fathoms under the strict definition.
6.08 ft) until the adoption of the international nautical mile. This was despite its being 1⁄ 1000 of a nautical mile (i.e. The British Admiralty in practice used a fathom of 6 ft. No longer an official unit in any nation. The distance between the two wickets on a cricket pitch. US and Commonwealth) nations to measure heights of horses.ĭefined as exactly 0.9144 m by the international yard and pound agreement of 1959ġ00 links, 4 rods, or 1⁄ 10 of a furlong. Still used in some English-speaking (i.e. Table of length equivalent unitsĪbbreviation of "thousandth of an inch". Before this date, the most precise measurement of the imperial Standard Yard was 0.914 398 415 metres.
Metric equivalents in this article usually assume the latest official definition. The Medical Act 1858 transferred to The Crown the right to publish the official pharmacopoeia and to regulate apothecaries' weights and measures. Imperial apothecaries' measures, based on the imperial pint of 20 fluid ounces, were introduced by the publication of the London Pharmacopoeia of 1836, the Edinburgh Pharmacopoeia of 1839, and the Dublin Pharmacopoeia of 1850. The three colleges published, at infrequent intervals, pharmacopoeias, the London and Dublin editions having the force of law. In Scotland, apothecaries' units were unofficially regulated by the Edinburgh College of Physicians. At the time, apothecaries' weights and measures were regulated "in England, Wales, and Berwick-upon-Tweed" by the London College of Physicians, and in Ireland by the Dublin College of Physicians. Apothecaries' units Imperial standards of length 1876 in Trafalgar Square, LondonĪpothecaries' units are not mentioned in the acts of 18. The 1824 Act allowed the continued use of pre-imperial units provided that they were customary, widely known, and clearly marked with imperial equivalents. The Weights and Measures Act 1825 pushed back the date to 1 January 1826. The Weights and Measures Act 1824 was initially scheduled to go into effect on. The modern UK legislation defining the imperial system of units is given in the Weights and Measures Act 1985 (as amended). The system came into official use across the British Empire in 1826.īy the late 20th century, most nations of the former empire had officially adopted the metric system as their main system of measurement, but imperial units are still used alongside metric units in the United Kingdom and in some other parts of the former empire, notably Canada. The imperial units replaced the Winchester Standards, which were in effect from 1588 to 1825. The imperial system developed from earlier English units as did the related but differing system of customary units of the United States. The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments. The former Weights and Measures office in Seven Sisters, London (590 Seven Sisters Road) For the political ideology, see Imperialism. For an overview of UK and US units, see Imperial and US customary measurement systems. For United States customary units, see United States customary units. For the system of weight, see Avoirdupois. For the units used in England before 1824, see English units. This article is about the post-1824 measures used in the British Empire and countries in the British sphere of influence.