steelyard balance

The steelyard exemplifies the law of the lever, wherein, when balanced, the weight of the object being weighed, multiplied by the length of the short balance arm to which it is attached, is equal to the weight of the counterweight multiplied by the distance of the counterweight from the pivot.{{cite book |last1=Whewell |first1=William |author1-link=William Whewell |title=First principles of mechanics, with historical and practical illustrations |date=1832 |publisher=Deighton |location=Cambridge, England |oclc=13469803 |page=35}}

According to Thomas G. Chondros of Patras University, a simple steelyard balance with a lever mechanism first appeared in the ancient Near East over 5,000 years ago.{{cite book |last1=Paipetis |first1=S. A. |last2=Ceccarelli |first2=Marco |title=The Genius of Archimedes -- 23 Centuries of Influence on Mathematics, Science and Engineering: Proceedings of an International Conference held at Syracuse, Italy, June 8-10, 2010 |date=2010 |publisher=Springer Science & Business Media |isbn=9789048190911 |page=416}} According to Mark Sky of Harvard University, the steelyard was in use among Greek craftsmen of the 5th and 4th centuries BC, even before Archimedes demonstrated the law of the lever theoretically.{{cite web|last1=Simon|first1=Emily|title=Even Without Math, Ancients Engineered Sophisticated Machines|url=http://fas.harvard.edu/home/news_and_events/releases/math_10012007.html|publisher=Faculty of Arts & Science, Harvard University|date=11 October 2007|url-status=bot: unknown|archiveurl=https://web.archive.org/web/20071011010453/http://fas.harvard.edu/home/news_and_events/releases/math_10012007.html|archivedate=11 October 2007}} The Latin name statera comes from the Ancient Greek στατήρ (statḗr). Roman and Chinese steelyards were independently invented around 200 BC. Steelyards dating from AD 100 to 400 have been unearthed in Great Britain. Steelyards and their components have also been excavated from shipwrecks of the Byzantine period in the Mediterranean and the Red Sea, such as the 7th-century wreck at Yassi Ada, Turkey, and the mid-first millennium shipwreck at Black Assarca Island, Eritrea. The Oxford English Dictionary suggests that the name "steelyard" is derived from steel combined with yard, influenced by an allusion to the Steelyard, the main trading base of the Hanseatic League in London in the 14th century.{{OED|steelyard, n.2}}

File:Grade II Listed Steelyard, Fountain Lane (geograph 3842770).jpg]]

Large steelyard balances (known as cart balances), both public and private, were a common feature in agricultural areas in England from the eighteenth century forward. An example of a public cart steelyard remains at Soham, Cambridgeshire, and another is at Woodbridge, Suffolk.{{cite web|title=Steelyard at the Fountain Inn|url=https://historicengland.org.uk/listing/the-list/list-entry/1331736|website=Historic England|accessdate=3 September 2016}}{{cite book|last1=Slight|first1=James|last2=Burn|first2=Robert Scott|editor1-last=Stephens|editor1-first=Henry|title=The Book of Farm Implements & Machines|publisher=Blackwood|location=Edinburgh|year=1868|oclc=458892190|pages=425–428|chapter=Machines for the products of the soil}}{{cite book|last1=Fairhall|first1=David|title=East Anglian shores : history, harbours, rivers, fisheries, pubs and architecture|date=2013|publisher=Bloomsbury|isbn=9781472903402|page=123}}

Steelyards of different sizes have been used to weigh loads ranging from ounces to tons. A small steelyard could be a foot or less in length and thus conveniently used as a portable device that merchants and traders could use to weigh small ounce-sized items of merchandise. In other cases a steelyard could be several feet long and used to weigh sacks of flour and other commodities. Even larger steelyards were three stories tall and used to weigh fully laden horse-drawn carts.

A Scandinavian steelyard is a variant which consists of a bar with a fixed weight attached to one end, a movable pivot point, and an attachment point for the object to be weighed at the other end. Once the object to be weighed is attached to its end of the bar, the pivot point, which is frequently a loop at the end of a cord or chain, is moved until the bar is balanced. The bar is calibrated so that the object's weight can be read off directly from the position of the pivot. This type is known in Sweden, Denmark, Norway and Finland

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File:Besman (ur Nordisk familjebok).png|Scandinavian steelyard balance with moveable pivot

File:Scandinavian steelyard balance movable handle fixed hook 82 cm wide Sweden.jpg|Scandinavian steelyard balance

File:A Roman steelyard and weight Wellcome M0000471.jpg|Steelyard balance from ancient Rome

File:Scandinavian steelyard balance Nyhammar Grangaerde Sweden max 10 kilos 62 cm wide.jpg|Swedish steelyard balance with fixed weight and movable, combined hook and handle

• Weigh house

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{{Commons category|Steelyard balances}}

• [https://archive.org/details/anelementarytre02parkgoog/page/n125 The physics of the steelyard]
• [https://archive.org/details/anelementarytre01bowsgoog To calibrate a steelyard]
• [http://www.gtj.org.uk/en/item1/28757 Roman steelyard and weight from Caernarfon]
• [http://www.scales-and-weights.com/scales/html/steelyards/romschnell.htm Iron steelyard]
• [http://www1.fis.uc.pt/museu/65ing.htm Steelyard with sliding weight]
• [http://www.metmuseum.org/toah/ho/05/waa/ho_1980.416ab.htm Steelyard Weight and Hook]
• [http://www.ingenious.org.uk/See/?s=S1&ObjectID=%7B1CA5AA74-23C4-CE56-7591-418A53F42CF2%7D&source=Search&target=SeeMedium A Roman steelyard, 79 AD]
• [http://www.china-window.com/china_culture/china_culture_essentials/chinese-steelyard-ganchen.shtml The Chinese steelyard dates to 200 B.C.E.]
• [http://www.ukdfd.co.uk/ukdfddata/showrecords.php?product=915&sort=2&cat=all&page=1 Roman steelyards unearthed in Britain]
• [https://web.archive.org/web/20060722222436/http://www.thefountain.co.uk/hist.htm A three-storey steelyard]

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Category:Weighing instruments