Тас салмағының тарихы және өлшемдері

Imperial unit of mass equal to 14 pounds
the European unit of mass

The stone or stone weight (abbreviation: st.) is an English and British imperial unit of mass equal to 14 pounds (6.35 kg). The stone continues in customary use in the United Kingdom and Ireland for body weight. England and other Germanic speaking countries of Northern Europe formerly used various standardised "stones" for trade, with their values ranging from about 5 to 40 local pounds (2.3 to 18.1 kg) depending on the location and objects weighed. With the advent of metrication, Europe's various "stones" were superseded by or adapted to the kilogram from the mid 19th century onward.

The name "stone" derives from the historical use of stones for weights, a practice that dates back into antiquity. The Biblical law against the carrying of "diverse weights, a large and a small" is more literally translated as "you shall not carry a stone and a stone (אבן ואבן), a large and a small". There was no standardised "stone" in the ancient Jewish world, but in Roman times stone weights were crafted to multiples of the Roman pound. Such weights varied in quality: the Yale Medical Library holds 10 and 50 pound examples of polished serpentine, while a 40 pound example at the Eschborn Museum is made of sandstone.

The Scottish stone was equal to 16 Scottish pounds (17 lb 8 oz avoirdupois or 7.936 kg). In 1661, the Royal Commission of Scotland recommended that the Troy stone be used as a standard of weight and that it be kept in the custody of the burgh of Lanark. The tron (or local) stone of Edinburgh, also standardised in 1661, was 16 tron pounds (22 lb 1 oz avoirdupois or 9.996 kg). In 1789 an encyclopedic enumeration of measurements was printed for the use of "his Majesty's Sheriffs and Stewards Depute, and Justices of Peace,  and to the Magistrates of the Royal Boroughs of Scotland" and provided a county by county and commodity by commodity breakdown of values and conversions for the stone and other measures. The Scots stone ceased to be used for trade when the Weights and Measures Act 1824 established a uniform system of measure across the whole of the United Kingdom, which at that time included all of Ireland.

Before the early 19th century, as in England, the stone varied both with locality and with commodity. For example, the Belfast stone for measuring flax equaled 16.75 avoirdupois pounds. The most usual value was 14 pounds. Among the oddities related to the use of the stone was the practice in County Clare of a stone of potatoes being 16 lb in the summer and 18 lb in the winter. Under the guidance of the Metrication Board, the agricultural product markets achieved a voluntary switchover by 1976. The stone was not included in the Directive 80/181/EEC as a unit of measure that could be used within the EEC for "economic, public health, public safety or administrative purposes", though its use as a "supplementary unit" was permitted. The scope of the directive was extended to include all aspects of the EU internal market from 1 January 2010. With the adoption of metric units by the agricultural sector, the stone was, in practice, no longer used for trade; and, in the Weights and Measures Act 1985, passed in compliance with EU directive 80/181/EEC, In 1983, in response to the same directive, similar legislation was passed in Ireland. The act repealed earlier acts that defined the stone as a unit of measure for trade. The invariant plural form of stone in this context is stone (as in, "11 stone" or "12 stone 6 pounds"); in other contexts, the correct plural is stones (as in, "Please enter your weight in stones and pounds"). In Australia and New Zealand, metrication has entirely displaced stones and pounds since the 1970s. In many sports in both the UK and Ireland, such as professional boxing, wrestling, and horse racing, the stone is used to express body weights.

In the Netherlands, where the metric system was adopted in 1817, the pond (pound) was set equal to half a kilogram, and the steen (stone), which had previously been 8 Amsterdam pond (3.953 kg), was redefined as being 3 kg. In modern colloquial Dutch, a pond is used as an alternative for 500 grams or half a kilogram, while the ons is used for a weight of 100 grams, being 1/5 pond.