English unit

English unit is the American name for a unit in one of a number of systems of units of measurement, some obsolete, and some still in use in present-day USA, the UK, and elsewhere. The modern United States customary units system as a whole is not, and has never been, used in England, and the modern Imperial units system as a whole is not, and has never been, used in the United States. Both of those more specific subsystems are part of the English units.

Most of the units are based on, but not necessarily the same as, old units used in historical England. In spite of the name, 'English unit' does not refer to the (non-SI) system of units with similar names still in widespread but unofficial use in England and the rest of the United Kingdom. These other units with similar names, but often different sizes, in use the UK are called the Imperial System, and in most but not all cases have been phased out in favour of the Metric System.

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), inherited from tribes from Germany. 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 the English system 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 clear which system is being described. Some people also call it the "British system" in the US. It is interesting to note that referring to this system as the British or English system almost only occurs in the United States, mainly causing confusion in the United Kingdom when reading from American sources.

Length

; poppyseed : frac|1|4 of a barleycorn Fact|date=July 2008; barleycorn : Basic Anglo-Saxon unit, the length of a corn of barley. The unit survived after 1066, redefined as frac|1|3 inch. Note the relation to the "grain" unit of weight. ; digit : frac|3|4 inch; finger : frac|7|8 inch; hand : 4 inches; "ynch", inch : Anglo Saxon inch, 3 barleycorns. Based on the Roman "uncia" from 1066.; nail : 3 digits = frac|2|1|4 inches = frac|1|16 yard; palm : 3 inches; shaftment : Width of the hand and outstretched thumb, frac|6|1|2 "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 = frac|1|1|4 yard or 45 inches. Mostly for measuring clothing; fathom : From one fingertip on one hand to the other finger tip on the other hand, 6 feet; rod : Saxon "gyrd" measuring stick, might have been from 20 "natural feet". Retained its length but redefined as frac|16|1|2 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 (8) of furlongs.; league : Usually three miles. Intended to be an hour's walk.

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").

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.

Volume

General

In both the United Kingdom 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 frac|1|2 Ounce;Jigger: Mouthful × 2 = 1 oz.;Jack or Jackpot: Jigger × 2 = 2 oz.;Gill: Jack × 2 = 4 oz (U.S.) or 5 oz (imperial).;Cup: Gill × 2 = 8 oz.;Pint : Cup × 2 = 16 oz. (U.S.) or 20 oz (imperial) (and a "Pint's a pound the world around" or in the United Kingdom, "A pint of pure water weighs a pound and a quarter");Quart: Pint × 2 = 32 oz. (U.S.) or 40 oz (imperial);Pottle or Half Gallon: Quart × 2 = 64 oz. (U.S.) or 80 oz (imperial);Gallon: Pottle × 2 = 4 Quarts = 128 oz. (U.S.) or 160 oz (imperial);Peck: Gallon × 2;Kenning: Peck × 2 = 4 gal.;Bushel: Kenning × 2 = 8 gal.;Cask, Strike, or Coomb: Bushel × 2 = 16 gal.;Barrel: Cask × 2 = 32 gal.;Hogshead : Barrel × 2 = 64 gal.;Butt or Pipe: hogshead × 2 = 128 gal.;Tun : Butt × 2 = 256 gal. (A tun is a ton)

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

Wine

Brewery

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 frac|3|4 (barley) grains or about 48.6 milligrams.

Avoirdupois

; grain (gr) : 64.79891 mg, frac|1|7000 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 : frac|1|4 cwt; hundredweight (cwt) : 112 lb ("long") or 100 lb ("short"); ton : 20 cwtAdditions:; nail : frac|1|16 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 = frac|1|4 cwt (long)

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 the United Kingdom, 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.

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

Tower

; tower ounce : frac|18|3|4 dwt = 450 gr ≈ 29 g; tower pound : 12 oz T = 225 dwt = 5400 gr ≈ 350 g

Apothecary

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

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.

"See also:" slug and poundal.

See also

* Feudalism
* Domesday Book
* Weights and measures
* History of measurement
* Comparison of the imperial and US customary measurement systems
* Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States
* Approximate conversion of units
* Metrication
* Winchester measure
* Imperial units

External links

* [http://www.unc.edu/~rowlett/units/custom.html English Customary Weights and Measures]
* Jacques J. Proot's [http://users.aol.com/jackproot/met/spvolas.html Anglo-Saxon weights & measures] page.
* Alexander Justice, " [http://pierre-marteau.com/wiki/index.php?title=London:Measures A General Discourse of the Weights and Measures] " (London, 1707).