English unit

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English unit refers to a unit in one of a number of systems of units of measurement, some obsolete, and some still in use. In spite of the name, it does not necessarily refer to the (non-SI) system of units still in widespread, but mostly unofficial, use in England itself. The latter is known outside the United States as the Imperial System. The American term 'English unit' includes the Imperial units as well as various other U.S. units such as the U.S. gallon (Queen Anne's wine gallon) and the U.S. bushel (Winchester bushel).

Various standards under the name 'English units' have applied at different times, in different places and for different things. Prior to the Battle of Hastings in 1066 the Anglo-Saxon system of measurement had been based on the units of the barleycorn and the gyrd (rod). This system presumably had Germanic origins. After the Norman conquest, Roman units were reintroduced. The resultant system of English units was a combination of the Anglo-Saxon and Roman systems.

Later development of the English system continued by defining the units by law in the Magna Carta of 1215, and issuing measurement standards from the then capital Winchester. Standards were renewed in 1496, 1588 and 1758. The last Imperial Standard Yard in bronze was made in 1845; it served as the standard in the United Kingdom until the yard was internationally redefined as 0.9144 metre in 1959 (statutory implementation: Weights and Measures Act of 1963).

The use of English units spread throughout the British Isles and to the British colonies. These units form the basis for the Imperial system formerly used in Commonwealth countries and the customary system used in the United States. Whilst these two systems are quite similar there are a number of notable differences between the Imperial and U.S. systems.

Usage of the term "English System" or "English Unit" is common in the US, but it is problematical. It can be ambiguous. It usually refers to either the Imperial System or the US Customary System, and in cases where these two systems differ, it is not not clear which system is being described.

Contents

[edit] Historical English units

[edit] Length

poppyseed 
¼ of a barleycorn
barleycorn 
Basic Anglo-Saxon unit, the length of a corn of barley. The unit survived after 1066, redefined as 1/3 inch. Note the relation to the grain unit of weight.
digit 
¾ inch
finger 
7/8 inch
hand 
4 inches
ynch, inch 
Anglo Saxon inch, 3 barleycorns. Based on the Roman uncia from 1066.
nail 
3 digits = 2¼ inches = 1/16 yard
palm 
3 inches
shaftment 
Width of the hand and outstretched thumb, 6½ ynches before 1066, 6 inches thereafter
span 
Width of the outstretched hand, from the tip of the thumb to the tip of the little finger, 3 palms = 9 inches
foot 
Usually 13 inches but also other variants. Shortened to 12 inches by basing it on the Roman pes from 1066.
cubit 
Forearm, 18 inches
yard 
Introduced after 1066, 3 feet = 36 inches.
ell 
Elbow, 20 nails = 1¼ yard or 45 inches. Mostly for measuring clothing
fathom 
From one fingertip to the other, 6 feet
rod 
Saxon gyrd measuring stick, might have been from 20 "natural feet". Retained its length but redefined as 16 ½ Roman feet after 1066.
chain 
four linear rods. Named after the length of surveyor's chain used to measure distances until quite recently. Any of several actual chains used for land surveying and divided in links. Gunter's chain, introduced in the 17th century, is 66 feet.
furlong 
"One plough's furrow long" (Saxon furrow is furh), the distance a plough team could be driven without rest. This varied from region to region depending on soil type and local habit. In modern context, it is deemed to be 660 feet, 40 rods or ten chains.
mile 
Introduced after 1066, originally the Roman mile at 5000 feet, in 1592 it was extended to 5280 feet to make it an even number of furlongs, i.e. 8.
league 
Usually three miles. Intended to be an hour's walk.

[edit] Area

perch
one rod, when referring to length; one square rod when referring to area; one rod by one foot by a foot and a half when referring to volume (usually specifically for masonry stonework)
acre
area of land one chain (four rods) in width by one furlong in length. As the traditional furlong could vary in length from country to country, so did the acre. In England an acre was 4,840 square yards, in Scotland 6,150 square yards and in Ireland 7,840 square yards. It is a Saxon unit, meaning field. Probably meant to be "as much area as could be plowed in one day".
rood
one quarter of an acre, confusingly sometimes called an acre itself in many ancient contexts. One furlong in length by one rod in width, or 40 square rods.
carucate
an area equal to that which can be ploughed by one eight-oxen team in a single year (also called a plough or carve). Approximately 120 roods.
bovate
the amount of land one ox can plough in a single year (also called an oxgate). Approximately 15 roods or one eighth of a carucate.
virgate
the amount of land a pair of oxen can plough in a single year. Approximately 30 roods (also called yard land).

[edit] Administrative units

hide
four to eight bovates. A unit of yield, rather than area, it measured the amount of land able to support a single household for agricultural and taxation purposes.
knight's Fee
five hides. A knight's fee was expected to produce one fully equipped soldier for a knight's retinue in times of war.
hundred
or wapentake - 100 hides grouped for administrative purposes.

[edit] Volume

[edit] General

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In both Britain and America, in addition to perch as a measure of length, there is also the perch which refers to the volume measurement of stone; one perch is equal to 16.5 ft × 1.5 ft × 1 ft = 24.75 cu. ft. of dry stone. The relationship to the unit of length (one perch = 16.5 feet) should be obvious.

Units of volume included:

Mouthful
about ½ Ounce
Jigger
Mouthful × 2
Jack or Jackpot
Jigger × 2
Jill or Gill
Jack × 2
Cup
Jill × 2
Pint 
Cup × 2 (and a "Pint's a pound the world around" or in Britain, "A pint of pure water weighs a pound and a quarter")
Quart
Pint × 2
Pottle or Half Gallon
Quart × 2
Gallon
Pottle × 2
Peck
Gallon × 2
Half Bushel
Peck × 2
Bushel
Half bushel × 2
Cask, Strike, or Coomb
Bushel × 2
Barrel
Cask × 2
Hogshead 
Barrel × 2
Butt or Pipe
hogshead × 2
Tun 
Butt × 2 (A tun is a ton)

A Tun would actually be about 2,048 lb. but is a pretty close estimate given that you could derive the weight and volume all from mouthfuls of water.

[edit] Wine

English casks of wine [1]
gallon rundlet barrel tierce hogshead firkin, puncheon, tertian pipe, butt tun
1 tun
1 2 pipes, butts
1 1+1⁄2 3 firkins, puncheons, tertians
1 1+1⁄3 2 4 hogsheads
1 1+1⁄2 2 3 6 tierces
1 1+1⁄3 2 2+2⁄3 4 8 barrels
1 1+3⁄4 2+1⁄3 3+1⁄2 4+2⁄3 7 14 rundlets
1 18 31+1⁄2 42 63 84 126 252 gallons (US/wine)
3.79 68.14 119.24 158.99 238.48 317.97 476.96 953.92 litres
1 15 26+1⁄4 35 52+1⁄2 70 105 210 gallons (imperial)
4.55 68.19 119.3 159.1 238.7 318.2 477.3 954.7 litres

[edit] Brewery

English casks of ale and beer [2]
gallon firkin kilderkin barrel hogshead (butt) (tun) Year designated
1 tuns
1 1+3⁄4 butts
1 3 5+1⁄4 hogsheads
1 1+1⁄2 4+1⁄2 7+7⁄8 barrels
1 2 3 9 15+3⁄4 kilderkins
1 2 4 6 18 31+1⁄2 firkins
1 8 16 32 48 144 252 ale gallons (ale) (1454)
= 4.62 = 36.97 = 73.94 = 147.88 = 221.82 = 665.44 = 1164.52 litres (ale)
1 9 18 36 54 162 283+1⁄2 ale gallons (beer)
= 4.62 = 41.59 = 83.18 = 166.36 = 249.54 = 748.62 = 1310.09 litres (beer)
1 8+1⁄2 17 34 51 ale gallons 1688
= 4.62 = 39.28 = 78.56 = 157.12 = 235.68 litres
1 9 18 36 54 ale gallons 1803
= 4.62 = 41.59 = 83.18 = 166.36 = 249.54 litres
1 9 18 36 54 imperial gallons 1824
= 4.55 = 40.91 = 81.83 = 163.66 = 245.49 litres

[edit] Weight

The Avoirdupois, Troy and Apothecary systems of weights all shared the same finest unit, the grain, however they differ as to the number of grains there are in a dram, ounce and pound. Originally, this grain was the weight of a grain seed from the middle of an ear of barley. There also was a smaller wheat grain, said to be ¾ (barley) grains or about 48.6 milligrams.

[edit] Avoirdupois

grain (gr) 
64.79891 mg, 1/7000th of a pound
dram/drachm (dr) 
27.34375 gr (sixteenth of an ounce) (possibly originated as the weight of silver in ancient Greek coin drachma)
ounce (oz) 
16 dr = 437.5 grains ≈ 28 g
pound (lb) 
16 oz = 7000 grains ≈ 454 g
quarter 
¼ cwt
hundredweight (cwt) 
112 lb (long) or 100 lb (short)
ton 
20 cwt

Additions:

nail 
1/16 cwt = 7 lb
clove 
7 lb (wool)
stone (st) 
2 cloves = 14 lb (an Anglo-Saxon unit changed to fit in)
tod 
2 st = ¼ cwt (long)

[edit] Troy and Tower

The Troy and Tower pounds and their subdivisions were used for coins and precious metals. The Tower pound, which is based upon an earlier Anglo-Saxon pound, was abolished in 1527.

In terms of (silver) currency a pound was 20 shillings of 12 pennies each (i.e. 240) from the late 8th century (Charlemagne/Offa of Mercia) to 1971 in Great Britain, but lighter than a troy one. Most old European currencies, like mark, shilling/solidus/groschen/øre, penny/pfennig/denar, taler/dollar/krone, florin/gulden/guilder/pound/złoty also belong into this monetary system.

[edit] Troy
grain (gr) 
≈ 65 mg
pennyweight (dwt) 
24 gr ≈ 1.56 g
ounce (oz t) 
20 dwt = 480 gr ≈ 31.1 g
pound (lb t) 
12 oz t = 5760 gr ≈ 373 g
mark
8 oz t

[edit] Tower
tower ounce 
18¾ dwt = 450 gr ≈ 29 g
tower pound 
12 oz T = 225 dwt = 5400 gr ≈ 350 g

[edit] Apothecary

grain (gr) 
≈ 65 mg
scruple (s ap) 
20 gr
dram (dr ap) 
3 s ap = 60 gr
ounce (oz ap) 
8 dr ap = 480 gr
pound (lb ap) 
5760 gr = 1 lb t

[edit] Others

Merchants/Mercantile pound 
15 oz tower = 6750 gr ≈ 437.4 g
London/Mercantile pound 
15 oz troy = 16 oz tower = 7200 gr ≈ 466.6 g
Mercantile stone 
12 lb L ≈ 5.6 kg
Tron pound (Edinburgh/Scots) 
16 oz Tron ≈ 623.5 g
Butcher's stone 
8 lb ≈ 3,63 kg
Sack 
26 st = 364 lb ≈ 165 kg

The carat was once specified as four grains in the English-speaking world. Some local units in the English dominion were (re-)defined in simple terms of English units, such as the Indian tola of 180 grains.

English pounds
Pound Pounds Ounces Grains Metric
avdp. troy tower merc. lond. metric avdp. troy tower (gr) (g) (kg)
Avoirdupois 1 175⁄144 35⁄27 28⁄27 35⁄36 10⁄11 16 14+7⁄12 15+5⁄9 7000 453.59 9⁄20
Troy 144⁄175 1 16⁄15 64⁄75 5⁄6 3⁄4 13+29⁄175 12 12+4⁄5 5760 373.24 3⁄8
Tower 27⁄35 15⁄16 1 4⁄5 3⁄4 7⁄10 12+12⁄35 11+1⁄4 12 5400 349.91 7⁄20
Merchant 27⁄28 75⁄64 5⁄4 1 15⁄16 7⁄8 15+3⁄7 14+1⁄16 15 6750 437.39 7⁄16
London 36⁄35 6⁄5 4⁄3 16⁄15 1 14⁄15 16+16⁄35 15 16 7200 466.55 7⁄15
Metric 11⁄10 4⁄3 10⁄7 8⁄7 15⁄14 1 17+3⁄5 16 17+1⁄7 7716 500.00 1⁄2

See also: slug and poundal.

[edit] See also

[edit] External links

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