English units

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English units are the historical units of measurement used in England up to 1824, which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications. The units were redefined in the United Kingdom in 1824 by a Weights and Measures Act, which retained many but not all of the unit names and redefined some of the definitions.

The term "English units" is ambiguous, as it could refer either to the imperial units used in the UK, or to United States customary units, which retains some unit names but has some different definitions.[1] (The terms imperial units or imperial measurements are used in the UK to refer to the non-metric system since they were used as a standard throughout the British Empire and the Commonwealth.)

History[edit]

Very little is known of the measurement units of the British Isles prior to Roman colonization in the 1st century CE. During the Roman period, Roman Britain relied on Ancient Roman units of measurement. During the Anglo-Saxon period, the North German foot of 335 millimetres (13.2 inches) was the nominal basis for other units of linear measurement. The foot was divided into 4 palms or 12 thumbs. A cubit was 2 feet, an elne 4 feet. The rod was 15 Anglo-Saxon feet, the furlong 10 rods. An acre was 4 × 40 rods, i.e., 160 square rods or 36,000 square Anglo-Saxon feet. However, Roman units continued to be used in the construction crafts. From the time of Offa King of Mercia (8th century) until 1526 the Saxon pound, also known as the moneyers' pound (and later known as the Tower pound) was the fundamental unit of mass measurement.

Prior to the enactment of a law known as the Composition of Yards and Perches (Compositio ulnarum et perticarum)[2] some time between 1266 and 1303, the English system of measurement had been based on that of the Anglo-Saxons, inherited from tribes from northern Germany. The Compositio retained the Anglo-Saxon rod of 5.03 metres and the acre of 4 × 40 rods. However, it redefined the yard, foot, inch, and barleycorn to 1011 of their previous value. Thus, the rod went from 5 old yards to 5 12 new yards, or 15 old feet to 16 12 new feet. The furlong went from 600 old feet (200 old yards) to 660 new feet (220 new yards). The acre went from 36,000 old square feet to 43,560 new square feet. Scholars have speculated that the Compositio may have represented a compromise between two earlier systems of the units, the Anglo-Saxon and the Roman.

Contrary to popular belief, the Norman conquest of England had little effect on British weights and measures other than to introduce one new unit: the bushel. William the Conqueror, in one of his first legislative acts, confirmed existing Anglo-Saxon measurement, a position which was consistent with Norman policy in dealing with occupied peoples. Another popular myth is that the Magna Carta of 1215 (specifically chapter 35) had any significant effect on English weights and measures, as this document only mentions one unit (the London Quarter) but does not define it.

Later development of the English system continued by defining the units by law and issuing measurement standards. 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 redefined by the international yard and pound agreement as 0.9144 metre in 1959 (statutory implementation: Weights and Measures Act of 1963). The English system then spread to other parts of the British Empire.

Length[edit]

Chart showing the relationships of distance measures.
Poppyseed 
about 14 of a barleycorn[3]
Line 
14 of a barleycorn[4]
Barleycorn 
13 of an inch, the base unit used for UK and US shoe sizes.
Digit 
34 inch
Finger 
78 inch
Hand 
4 inches
Ynch, inch 
Anglo Saxon inch, 3 barleycorns.
Nail 
3 digits = 2 14 inches = 116 yard
Palm 
3 inches
Shaftment 
Width of the hand and outstretched thumb, 6 12 ynches before 1066, 6 inches thereafter
Link 
7.92 inches or one 100th of a chain.[5]
Span 
Width of the outstretched hand, from the tip of the thumb to the tip of the little finger, 3 palms = 9 inches
Foot 
Prior to the Anglo-Saxon invasions, the Roman foot of 11.65 inches (296 mm) was used. The Anglo-Saxons introduced a North-German foot of 13.2 inches (335 mm), divided into 4 palms or 12 thumbs, while the Roman foot continued to be used in the construction crafts. In the late 13th century, the modern foot of 304.8 mm was introduced, equal to exactly 1011 Anglo-Saxon foot.
Cubit 
From fingertips to elbow, 18 inches.
Yard 
3 feet = 36 inches.
Ell 
From fingertip of outstretched arm to opposite shoulder, 20 nails = 1 14 yard or 45 inches. Mostly for measuring cloth
Fathom 
Distance fingertip to fingertip arms outstretched, 6 feet
Rod (= perch) (= pole)
Used for surveying land and in architecture. The rod is the same length today as in Anglo-Saxon times. It is 16 1/2 feet long. The pole is commonly used as a measurement for Allotment Gardens. (See also perch as an area and a volume unit.)
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), nominally the distance a plough team could be driven without rest, it was actually a very precise measure of 40 rods or 600 Anglo-Saxon feet (ten percent longer than the modern foot). Thus, 660 modern 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 a whole number (8) of furlongs.
League 
Usually three miles. Intended to be an hour's walk.

Area[edit]

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. Traditionally said to be "as much area as could be ploughed 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 acres.
Bovate
the amount of land one ox can plough in a single year (also called an oxgang). Approximately 15 acres or one eighth of a carucate.
Perch
an area equal to one square rod. (See also perch as a length and volume unit.)
Virgate
the amount of land a pair of oxen can plough in a single year. Approximately 30 acres (also called yard land).

Administrative units[edit]

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.

Volume[edit]

General[edit]

Chart showing the relationships of volume measures.
Dram
60 minim or drops or 18 fluid ounce (fl oz)
Teaspoon
80 minim or drops or 16 fl oz
Tablespoon or mouthful
4 dram, 3 teaspoons or 12 fl oz
Pony
6 dram or 34 fl oz
Jigger
3 tablespoons, 2 pony or 1.5 fl oz
Jack or jackpot
5 tablespoons or 2.5 fl oz (double this for milk and beer in Northern England)
Gill
2 jack or 5 fl oz (or double this for milk and beer in Northern England)
Cup
2 gill or 10 fl oz
Pint
2 cup or 20 fl oz ("A pint of pure water weighs a pound and a quarter")
Quart
2 pint, 40 fl oz or 14 gallon
Pottle
2 quart, 80 fl. oz or 12 gallon
Gallon
2 pottle, 4 quarts, 8 pints or 160 fl oz

Dry goods[edit]

Dry gallon
4 dry quarts or 8 dry pints
Peck
2 dry gallons
Kenning
2 peck or 4 dry gallons
Bushel
2 kenning, 4 pecks or 8 dry gallons
Strike
2 bushels or 16 dry gallons
Coomb or dry barrel
2 strike, 4 bushels or 32 dry gallons
Dry hogshead
2 Coomb, 64 dry gallons or 14 dry tun
  tablespoon pony jack gill cup pint quart pottle gallon peck kenning bushel strike coomb hogshead butt/pipe 2n gal.
1 tablespoon = 1 12 14 18 116 132 164 1128 1256 1512 11024 12048 14096 18192 116384 132768 –8
1 pony = 2 1 12 14 18 116 132 164 1128 1256 1512 11024 12048 14096 18192 116384 –7
1 jack = 4 2 1 12 14 18 116 132 164 1128 1256 1512 11024 12048 14096 18192 –6
1 gill = 8 4 2 1 12 14 18 116 132 164 1128 1256 1512 11024 12048 14096 –5
1 cup = 16 8 4 2 1 12 14 18 116 132 164 1128 1256 1512 11024 12048 –4
1 pint = 32 16 8 4 2 1 12 14 18 116 132 164 1128 1256 1512 11024 –3
1 quart = 64 32 16 8 4 2 1 12 14 18 116 132 164 1128 1256 1512 –2
1 pottle = 128 64 32 16 8 4 2 1 12 14 18 116 132 164 1128 1256 –1
1 gallon = 256 128 64 32 16 8 4 2 1 12 14 18 116 132 164 1128 0
1 peck = 512 256 128 64 32 16 8 4 2 1 12 14 18 116 132 164 1
1 kenning = 1,024 512 256 128 64 32 16 8 4 2 1 12 14 18 116 132 2
1 bushel = 2,048 1,024 512 256 128 64 32 16 8 4 2 1 12 14 18 116 3
1 strike = 4,096 2,048 1,024 512 256 128 64 32 16 8 4 2 1 12 14 18 4
1 coomb = 8,192 4,096 2,048 1,024 512 256 128 64 32 16 8 4 2 1 12 14 5
1 hogshead = 16,384 8,192 4,096 2,048 1,024 512 256 128 64 32 16 8 4 2 1 12 6
1 butt/pipe = 32,768 16,384 8,192 4,096 2,048 1,024 512 256 128 64 32 16 8 4 2 1 7

Specific goods[edit]

Oil barrel
35 gallons (or 42 wine gallons)
Perch
24.75 cubic feet of dry stone, derived from the more commonly known perch, a unit of length equal to 16.5 feet.[6]
Cord
128 cubic feet of firewood, a stack of firewood 4 ft × 4 ft × 8 ft[7]

Ale, beer and liquids[edit]

Pin
4.5 gallons or 18 beer barrel
Firkin
2 pins, 9 gallons (ale, beer or goods) or 14 beer barrel
Kilderkin
2 firkins, 18 gallons or 12 beer barrel
Beer barrel
2 kilderkins, 36 gallons or 23 beer hogshead
Beer hogshead
3 kilderkins, 54 gallons or 1.5 beer barrels
Beer pipe or butt
2 beer hogsheads, 3 beer barrels or 108 gallons
Beer tun
2 beer pipes or 216 gallons
English brewery cask units[8]
gallon firkin kilderkin barrel hogshead Year designated
1 hogsheads
1 1 12 barrels
1 2 3 kilderkins
1 2 4 6 firkins
1 8 16 32 48 ale gallons (1454)
= 4.621 l = 36.97 l = 73.94 l = 147.9 l = 221.8 l
1 9 18 36 54 beer gallons
= 4.621 l = 41.59 l = 83.18 l = 166.4 l = 249.5 l
1 8 12 17 34 51 ale gallons 1688
= 4.621 l = 39.28 l = 78.56 l = 157.1 l = 235.7 l
1 9 18 36 54 ale gallons 1803
= 4.621 l = 41.59 l = 83.18 l = 166.4 l = 249.5 l
1 9 18 36 54 imperial gallons 1824
= 4.546 l = 40.91 l = 81.83 l = 163.7 l = 245.5 l

Wine[edit]

Wine is traditionally measured based on the wine gallon established by Queen Anne in 1707. Defined as 231 cubic inches, it differs from the later imperial gallon, but is equal to the United States customary gallon.

Rundlet
18 wine gallons or 17 wine pipe
Wine barrel
31.5 wine gallons or 12 wine hogshead
Tierce
42 wine gallons, 12 puncheon or 13 wine pipe
Wine hogshead
2 wine barrels, 63 wine gallons[9] or 14 wine tun
Puncheon or tertian
2 tierce, 84 wine gallons or 13 wine tun
Wine pipe or butt
2 wine hogshead, 3 tierce, 7 roundlet or 126 wine gallons
Wine tun
2 wine pipe, 3 puncheon or 252 wine gallons
English wine cask units[10]
gallon rundlet barrel tierce hogshead puncheon, tertian pipe, butt tun
1 tun
1 2 pipes, butts
1 1 12 3 puncheons, tertians
1 1 13 2 4 hogsheads
1 1 12 2 3 6 tierces
1 1 13 2 2 23 4 8 barrels
1 1 34 2 13 3 12 4 23 7 14 rundlets
1 18 31 12 42 63 84 126 252 gallons (wine)
3.785 68.14 119.24 158.99 238.48 317.97 476.96 953.92 litres
1 15 26 14 35 52 12 70 105 210 gallons (imperial)
4.546 68.19 119.3 159.1 238.7 318.2 477.3 954.7 litres

Weight[edit]

Chart showing the relationships of weight measures.

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. This grain was legally defined as the weight of a grain seed from the middle of an ear of barley. There also was a smaller wheat grain, said to be 34 (barley) grains or about 48.6 milligrams.

Avoirdupois[edit]

Grain (gr) 
64.79891 mg, 17000 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 (NB: 'lb' stands for libra)
Quarter 
14 cwt
Hundredweight (cwt) 
112 lb
Ton 
20 cwt

Additions:

Nail 
116 cwt = 7 lb
clove 
7 lb (wool) or 8 lb (cheese)
Stone (st) 
2 cloves = 14 lb (an Anglo-Saxon unit changed to fit in)
Tod 
2 st = 14 cwt (long)

Troy and Tower[edit]

The Troy and Tower pounds and their subdivisions were used for coins and precious metals. The Tower pound, which was based upon an earlier Anglo-Saxon pound, was replaced by the Troy pound when a proclamation dated 1526 required the Troy pound to be used for mint purposes instead of the Tower pound.[11] No standards of the Tower pound are known to have survived.[12]

In terms of nominal currency units, a pound was 20 shillings of 12 pennies each (i.e. 240) from the late 8th century (Charlemagne/Offa of Mercia) to 1971 in the United Kingdom.

Troy[edit]

Grain (gr) 
= 64.79891 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

Tower[edit]

Grain (gr) 
= 4564 gr t ≈ 45.5 mg
Pennyweight (dwt) 
32 gr T = 22 12 gr t ≈ 1.46 g
Tower ounce 
24 dwt T = 640 gr T = 18 34 dwt t = 450 gr t ≈ 29 g
Tower pound 
12 oz T = 240 dwt T = 7680 gr T = 225 dwt t = 5400 gr t ≈ 350 g
Mark
8 oz T =

Apothecary[edit]

Grain (gr) 
= 64.79891 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

Others[edit]

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
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
Unit Pounds Ounces Grains Metric
Avdp. Troy Tower Merchant London Metric Avdp. Troy Tower Troy Tower g kg
Avoirdupois 1 175/144 = 1.21527 35/27 = 1.296 28/27 = 1.037 35/36 = 0.972 ≈ 0.9072 16 14 7/12 = 14.583 15 5/9 = 15.5 7000 09955 5/9 ≈ 454 5/11
Troy 144/175 ≈ 0.8229 1 16/15 = 1.06 64/75 = 0.853 4/5 = 0.8 ≈ 0.7465 13 29/175 ≈ 13.17 12 12 4/5 = 12.8 5760 08192 ≈ 373 3/8
Tower 27/35 ≈ 0.7714 15/16 = 0.9375 1 4/5 = 0.8 3/4 = 0.75 ≈ 0.6998 12 12/35 ≈ 12.34 11 1/4 = 11.25 12 5400 07680 ≈ 350 7/20
Merchant 27/28 ≈ 0.9643 75/64 = 1.171875 5/4 = 1.25 1 15/16 = 0.9375 ≈ 0.8748 15 3/7 ≈ 15.43 14 1/16 = 14.0625 15 6750 09600 ≈ 437 7/16
London 36/35 ≈ 1.029 5/4 = 1.25 4/3 = 1.3 16/15 = 1.06 1 ≈ 0.9331 16 16/35 ≈ 16.46 15 16 7200 10240 ≈ 467 7/15
Metric ≈ 1.1023 ≈ 1.3396 ≈ 1.4290 ≈ 1.1431 ≈ 1.0717 1 ≈ 17.64 ≈ 16.08 ≈ 17.15 7716 10974 = 500 = 1/2

See also[edit]

References[edit]

  1. ^ Marks' Standard Handbook for Mechanical Engineers, McGraw Hill, 2006
  2. ^ Zupko, Ronald Edward (1977). British Weights and Measures: A History from Antiquity to the Seventeenth Century. University of Wisconsin Press. pp. 20–21. ISBN 978-0-299-07340-4. 
  3. ^ "poppyseed". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. 
  4. ^ H. Arthur Klein (1974). The world of measurements: masterpieces, mysteries and muddles of metrology. New York: Simon and Schuster. p. 63. 
  5. ^ Merriam Webster Online Dictionary, Link definition
  6. ^ Blocksma, Mary. Reading the Numbers. New York: Penguin Books, 1989.
  7. ^ "cord, n 1". Oxford English Dictionary (2 ed.). Oxford, England: Oxford University Press. 1989. "from Richard Boyle, 1616" 
  8. ^ http://www.sizes.com/units/barrel_alebeer.htm
  9. ^ Unwin, Tim (1991). Wine and the Vine. London: Routledge. p. 364. ISBN 0-415-14416-7. 
  10. ^ http://www.sizes.com/units/barrel_wine.htm
  11. ^ A proclamation of Henry VIII, 5 November 1526. Proclamation 112 in Paul L. Hughes and James F. Larkin, editors. Tudor Royal Proclamations. Volume 1. New Haven: Yale University Press,1964.[1]
  12. ^ R. D. Connor and A. D. C. Simpson.Weights and Measures in Scotland. A European Perspective.National Museums of Scotland and Tuckwell Press, 2004, page 116, quoting from H. W. Chisholm, Seventh Annual Report of the Warden for the Standards..for 1872-73 (London, 1873), quoting from 1864 House of Commons Paper.[2]

External links[edit]