Stone (mass)
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The stone is a unit of weight, that is, the force the gravitational field of the Earth exerts on a mass. The Imperial unit of mass is the slug, which weighs 32.17405 pounds -- or 2.29815 stone -- in Earth's gravitational field. The stone is part of the Imperial system of weights and measures used in the United Kingdom, and formerly used in several Commonwealth countries. It is equal to 14 pounds (more precisely avoirdupois pounds), or 6.35029318 kilograms.
Eight stone make a hundredweight in the Imperial system.
When used as the unit of measurement, the plural form of stone is correctly stone (as in, "11 stone"), though stones is sometimes used, but not usually by British natives. The abbreviation is st. When describing the units, the correct plural is stones (as in, "Please enter your weight in stones and pounds").
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[edit] History
The stone was originally used for weighing agricultural commodities. Historically the number of pounds in a stone varied by commodity, and was not the same in all times and places even for one commodity. Potatoes, for example, were traditionally sold in stone and half-stone (14-pound and 7-pound) quantities but the OED contains examples[1] including:
| Commodity | Number of Pounds |
|---|---|
| Wool | 14, 15, 24 |
| Wax | 12 |
| Sugar and spice | 8 |
| Beef and Mutton | 8 |
Another example is the definition of the "stone" in the 1772 edition of Encyclopaedia Britannica[2] which reads "STONE also denotes a certain quantity or weight of some commodities. A stone of beef, in London, is the quantity of eight pounds; in Hertfordshire, twelve pounds; in Scotland sixteen pounds."
[edit] Current use
Although the 1985 Weights and Measures Act[3] expressly prohibited the use of the stone as a unit of measure for purposes of trade (other than as a supplementary unit), the stone remains widely used within the United Kingdom (and Ireland) as a means of expressing human body weight. People in these countries normally describe themselves as weighing, for example, "11 stone 4" (11 stone and 4 pounds), rather than "72 kilograms" in most other countries, or "158 pounds" (the conventional way of expressing the same weight in the United States and Canada).
Its widespread colloquial use may be compared to the persistence in the United Kingdom of other Imperial units like the foot, the inch, and the mile, despite these having been supplanted entirely or partly by metric units in official use and other contexts. Thus on a National Health Service Web site the user may select either metric or Imperial units,[4] but the law requires that if this information is officially recorded, then such records shall be in metric units.[5]
[edit] See also
[edit] References
- ^ OED Definition for Stone - meaning 14a
- ^ Encyclopaedia Britannica Vol III, Edinburgh - 1772
- ^ 1985 Weights and Measures Act [1]
- ^ NHS Online Calorie Counter
- ^ [2] The National Child Measurement Program - Guidance for PCTs 2008/9 school year
