The tun (Old English: tunne, Latin: tunellus, Medieval Latin: tunna) is an English unit of liquid volume (not weight), used for measuring wine,[1] oil or honey. Typically a large vat or vessel, most often holding 252 wine gallons, but occasionally other sizes (e.g. 256, 240 and 208 gallons) were also used.[2] The modern tun is about 954 litres.
The word tun is etymologically related to the word ton for the unit of mass, the mass of a tun of wine being approximately one long ton, which is 2240 pounds (1016 kg).
History edit
Originally, the tun was defined as 256 wine gallons;[nb 1] this is the basis for the name of the quarter of 64 corn gallons. At some time before the 15th century, it was reduced to 252 wine gallons, so as to be evenly divisible by other small integers, including seven.[nb 2]
In one Early Modern English example from 1507, a tun is defined as 240 gallons.
He that ys a gawner owght to understonde there ys in a tunne lx systerns and every systern ys iiii galons be yt wyne or oylle. | He that is a gauger ought to understand that there is in a tunne 60 sesters, and every sester is 4 gallons, be it wine or oil. |
| —Untitled manuscript, consisting of a list of various customs duties, dated 15 July 1507[2][3][4] |
With the adoption of the Queen Anne wine gallon of 231 cubic inches in 1706 the tun approximated the volume of a cylinder with both diameter and height of 42 inches.[nb 3] These were adopted as the standard US liquid gallon and tun.
When the imperial system was introduced in 1824 the tun was redefined in the UK and colonies as 210 imperial gallons. The imperial tun remained evenly divisible by small integers.[nb 4] There was also little change in the actual value of the tun.[nb 5]
Standard tuns of wine came to serve as a measure of a ship's capacity.[5]
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Definitions edit
In the US customary system, the tun (symbol: US tu[6]) is defined as 252 US fluid gallons (about 954 litres).[6]
In the imperial system, the tun is defined as 210 imperial gallons (about 955 litres).
Conversions edit
Both the imperial and US tuns were subdivided into smaller units as follows.
| 1 tun | ≡ | 2 | butts or pipes |
| ≡ | 3 | puncheons or tertians | |
| ≡ | 4 | wine hogsheads[6] | |
| ≡ | 6 | tierces | |
| ≡ | 8 | wine barrels | |
| ≡ | 14 | rundlets | |
| Conversions of the imperial tun are as follows. | |||
| 1 imperial tun | ≡ | 210 | imperial gallons |
| ≡ | 1680 | imperial pints | |
| ≡ | 954.6789 | litres[nb 7] | |
| ≡ | 0.9546789 | cubic metres[nb 7] | |
| ≈ | 58258 | cubic inches | |
| ≈ | 33.7142 | cubic feet | |
| ≈ | 252.199484 | US fluid gallons | |
| ≈ | 2017.595875 | US fluid pints | |
| Conversions of the US tun are as follows. | |||
| 1 US tun | ≡ | 252 | US fluid gallons[6] |
| ≡ | 2016 | US fluid pints[6] | |
| ≡ | 953.9237769568 | litres[nb 8] | |
| ≡ | 0.953923769568 | cubic metres[nb 8] | |
| ≡ | 58212 | cubic inches | |
| ≡ | 33.6875 | cubic feet | |
| ≈ | 209.833895 | imperial gallons | |
| ≈ | 1678.671156 | imperial pints | |
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Explanatory notes edit
- ^ 256=28
- ^ 252 = 22×32×7
- ^ The volume, V, of this cylinder may be approximated from the height, h, and the radius, r, as follows.
V = πr2h ≈ 22⁄7×(21 in)2×42 in since π ≈ 22⁄7 = (22×32×7)×(3×7×11) cu in = 252×231 cu in
- ^ 210 = 2×3×5×7
- ^ The imperial tun is only about 0.0792% larger than the US tun assuming current definitions. Note that 5 imp gal ≈ 6 US gal.
- ^ The conversion to litres is approximate and given as a range to reflect the varying definitions of the gallon and the tun in terms of the gallon.
- ^ a b c The conversion to litres is exact assuming the current 4.54609-litre definition of the imperial gallon.
- ^ a b c The conversion to litres is exact assuming the current 25.4-millimetre definition of the international inch.