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Fathom
A fathom is a unit of length in the imperial and the U.S. customary systems equal to , used especially for measuring the depth of water. The fathom is neither an international standard (SI) unit, nor an internationally accepted non-SI unit. Historically it was the maritime measure of depth in the English-speaking world but, apart from within the US, charts now use metres. There are two yards (6 feet) in an imperial fathom. Originally the span of a man's outstretched arms, the size of a fathom has varied slightly depending on whether it was defined as a thousandth of an (Admiralty) nautical mile or as a multiple of the imperial yard. Formerly, the term was used for any of several units of length varying around . Etymology The term (pronounced ) derives (via Middle English ''fathme'') from the Old English ''fæðm'', which is cognate with the Danish word ''favn'' and means "embracing arms" or "pair of outstretched arms". It is maybe also cognate with the Old High German wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Sounding
Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditionally shown on nautical charts in fathoms and feet. The National Oceanic and Atmospheric Administration (NOAA), the agency responsible for bathymetric data in the United States, still uses fathoms and feet on nautical charts. In other countries, the International System of Units (metres) has become the standard for measuring depth. Terminology "Sounding" derives from the Old English ''sund'', meaning "swimming, water, sea"; it is not related to the word ''sound'' in the sense of noise or tones, but to ''sound'', a geographical term. Traditional terms for soundings are a source for common expressions in the English language, notably "deep six" (a sounding of 6 fathoms). On the Mississippi River in the 1850s, the leadsmen also used old-fashi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial Units
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 imperial system developed from earlier English units as did the Comparison of the imperial and US customary measurement systems, related but differing system of United States customary units, customary units of the United States. The imperial units replaced the Winchester measure, Winchester Standards, which were in effect from 1588 to 1825. The system came into official use across the British Empire in 1826. By the late 20th century, most nations of the former empire had metrication, 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 empi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Customary Units
United States customary units form a system of measurement units commonly used in the United States and most U.S. territories since being standardized and adopted in 1832. The United States customary system developed from English units that were in use in the British Empire before the U.S. became an independent country. The United Kingdom's system of measures evolved by 1824 to create the imperial system (with imperial units), which was officially adopted in 1826, changing the definitions of some of its units. Consequently, while many U.S. units are essentially similar to their imperial counterparts, there are noticeable differences between the systems. The majority of U.S. customary units were redefined in terms of the meter and kilogram with the Mendenhall Order of 1893 and, in practice, for many years before. T.C. Mendenhall, Superintendent of Standard Weights and MeasuresOrder of April 5, 1893, published as Appendix 6 to the Report for 1893 of the United States Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byzantine Units Of Measurement
Byzantine units of measurement were a combination and modification of the ancient Greek and Roman units of measurement used in the Byzantine Empire. Until the reign of Justinian I (527–565), no universal system of units of measurement existed in the Byzantine world, and each region used its traditional measures. Justinian began the process of standardization that resulted in a specifically Byzantine system, chiefly due to the need of such a system for the fiscal administration. Official measurement and weighing was performed subject to an array of charges including the ''mestikon'', ''miniatikon'', ''zygastikon'', ''kambaniatikon'', ''gomariatikon'', and ''samariatikon''. Despite the central government's insistence on the use of official measures, other systems continued to be used in parallel, whether due to local traditions or foreign influences, or in order to cover the necessities of specific trades or crafts. In addition, from the 12th century, foreign merchants such as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byzantine Units
Byzantine units of measurement were a combination and modification of the ancient Greek and Roman units of measurement used in the Byzantine Empire. Until the reign of Justinian I (527–565), no universal system of units of measurement existed in the Byzantine world, and each region used its traditional measures. Justinian began the process of standardization that resulted in a specifically Byzantine system, chiefly due to the need of such a system for the fiscal administration. Official measurement and weighing was performed subject to an array of charges including the ''mestikon'', ''miniatikon'', ''zygastikon'', ''kambaniatikon'', ''gomariatikon'', and ''samariatikon''. Despite the central government's insistence on the use of official measures, other systems continued to be used in parallel, whether due to local traditions or foreign influences, or in order to cover the necessities of specific trades or crafts. In addition, from the 12th century, foreign merchants such as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of a second, where the second is defined by a hyperfine transition frequency of caesium. The metre was originally defined in 1791 by the French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's polar circumference is approximately . In 1799, the metre was redefined in terms of a prototype metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meter (unit)
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of a second, where the second is defined by a hyperfine transition frequency of caesium. The metre was originally defined in 1791 by the French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's polar circumference is approximately . In 1799, the metre was redefined in terms of a prototype metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path trav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek Units Of Measurement
Ancient Greek units of measurement varied according to location and epoch. Systems of ancient weights and measures evolved as needs changed; Solon and other lawgivers also reformed them ''en bloc''. Some units of measurement were found to be convenient for trade within the Mediterranean region and these units became increasingly common to different city states. The calibration and use of measuring devices became more sophisticated. By about 500 BC, Athens had a central depository of official weights and measures, the '' Tholos'', where merchants were required to test their measuring devices against official standards. Length Some Greek measures of length were named after parts of the body, such as the (''daktylos'', plural: ''daktyloi'') or finger (having the size of a thumb), and the ('' pous'', plural: ''podes'') or foot (having the size of a shoe). The values of the units varied according to location and epoch (e.g., in Aegina a ''pous'' was approximately , whereas in Athen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yard
The yard (symbol: yd) is an English units, English unit of length in both the British imperial units, imperial and US United States customary units, customary systems of measurement equalling 3 foot (unit), feet or 36 inches. Since 1959 it has been by international yard and pound, international agreement standardized as exactly 0.9144 Metre, meter. A distance of 1,760 yards is equal to 1 mile. The theoretical survey foot, US survey yard is very slightly longer. Name The term, ''yard'' derives from the Old English , etc., which was used for branches, staves and measuring rods. It is first attested in the late 7th century Ine of Wessex#Laws, laws of Ine of Wessex, wherein the "yard of land" mentioned is the virgate, yardland, an old English unit of tax assessment equal to hide (unit), hide. Around the same time the Lindisfarne Gospels account of the messengers from John the Baptist in the Gospel of Matthew used it for a branch swayed by the wind. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmspan
The palm is an obsolete anthropic unit of length, originally based on the width of the human palm and then variously standardized. The same name is also used for a second, rather larger unit based on the length of the human hand. The width of the palm was a traditional unit in Ancient Egypt, Israel, Greece, and Rome and in medieval England, where it was also known as the hand,. handbreadth, or handsbreadth.. The length of the hand—originally the Roman "greater palm"—formed the palm of medieval Italy and France. In Spanish customary units ' or ' was the palm, while ' was the span, the distance between an outstretched thumb and little finger. In Portuguese ' or ' was the span. History Ancient Egypt The Ancient Egyptian palm () has been reconstructed as about . The unit is attested as early as the reign of Djer, third pharaoh of the First Dynasty, and appears on many surviving cubit-rods. The palm was subdivided into four digits () of about . Three palms made up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
