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Grain (measure)
Encyclopedia
A grain is a unit of measurement of mass
that is nominally based upon the mass of a single seed of a cereal
. From the Bronze Age into the Renaissance the average masses of wheat
and barley
grains were part of the legal definition of units of mass. However, there is no evidence of any country ever having used actual seeds or cereal grains. Rather, expressions such as "thirty-two grains of wheat, taken from the middle of the ear" appear to have been ritualistic formulas, essentially the premodern equivalent of legal boilerplate
.
The fundamental unit of the troy
, apothecary
and avoirdupois
systems, commonly known as the grain (or less commonly the barleycorn), is nominally based on the grain of barley. The fundamental unit of the pre-1527 English weight system for coins, known as Tower weights, was a different sort of grain known as the wheat-grain.
The grain is the only unit of mass measure common to the three traditional English mass and weight systems
(avoirdupois
, Apothecaries', troy
); the obsolete Tower grain was, by definition, exactly 45/64 of a troy grain.
Since 1958, the grain or troy grain (Symbol: gr) measure has been defined in terms of units of mass in the International System of Units
as precisely . However, the measure for pearl
s and diamond
s - the pearl grain and the metric grain - are equal to of a (metric) carat, i.e. 50 mg (0.77 gr).
There are precisely 7,000 grains per avoirdupois
pound in the Imperial and U.S. customary units
, and 5,760 grains in the Troy pound.
The grain is used to measure the mass of bullet
s, gunpowder
, smokeless powder
, and preformed gold foil; it is the measure used by the balances used in handloading
; bullets are measured in increments of one grain, gunpowder in increments of 0.1 grains. Moreover, the grain is used to weigh fencing
equipment, including the foil. In archery
, the grain is used to weigh arrows and arrow parts.
The grain is the most common unit used to measure the hardness of water. In particular it is used to quantitively describe the abundance of calcium Ca2+ and magnesium Mg2+ minerals in water. Typically, the measure is noted in Grains per Gallon
(GPG). Water, untreated, typically can measure up to 100 gpg. This measure is critical to setting accurately the resin cation bead regeneration cycle periodicity of both sodium chloride brine and potassium chloride brine flushed water softeners.
Grains are still used occasionally in medicine in the United States, especially in medical prescription
s, usually via the abbreviation "gr." For example, a regular tablet of aspirin
is sometimes referred to as "five grain aspirin," or 325 mg. Grains are commonly used for medication
s that have been included in the United States Pharmacopeia for many decades, such as codeine
, opium
and phenobarbital
combinations. For example, a prescription for tablets containing 325 mg of aspirin and 30 mg of codeine (brand name is Empirin with codeine), is written thus: "ASA gr. v c cod. gr. ss tablets," where "ASA" is short for aspirin (AcetylSalicylic Acid), "v" is the roman numeral for five, "c" is the abbreviation for "with" and "ss" stands for one-half. Likewise, a prescription for B&O Supprettes #15A, which is a compound medication containing belladonna alkaloid
s and opium
, may be written: "Belladonna gr. 1/4 c opium gr ss", as B&O Supprettes
#15A contain 16.2 mg (1/4 grain) of powdered belladonna and 30 mg (1/2 grain) of opium. Similarly, a prescription for 60 mg (1 grain) of phenobarbital is often written: "Phenobarb. gr. i". Formulations of these older medications (e.g., Donnatal
, Phenobarbital
, etc.), often use grains on the product label along with the metric equivalent. For example, Extended-Release Donnatal tablets contain (approximately 48.6 mg) of phenobarbital. Given the potential error in mistaking the abbreviations for "grains" and "grams" (gr and g, respectively), and for consistency with other medical orders, metric units are preferred to avoirdupois
or apothecary
units; hence, the use of grains in the medical profession is rapidly becoming outmoded.
Grains are also used in environmental permitting to quantify particulate emissions. Grains are used to measure the amount of moisture per cubic foot of air, a measure of absolute humidity.
At least since antiquity
, grains of wheat
or barley
were used by Mediterranean traders
to define units of mass; along with other seeds, especially those of the carob tree. According to a longstanding tradition, 1 carat (the mass of a carob seed) was equivalent to the weight of 4 wheat grains or 3 barleycorns. But since the weights of these seeds are highly variable, especially that of the cereals as a function of moisture, this is a convention more than an absolute law.
The history of the modern grain can be traced back to a royal decree in 13th century England:
The traditional reading of this text is that it refers to the troy pound, and that the reference to sterling pennies is purely symbolic. According to a more recent reading, however, the pound in question is the Tower pound, and it talks about the actual mass of real sterling pennies. The Tower pound, abolished in 1527, consisted of 12 ounces like the troy pound, but was lighter. In any case, with both readings one needs to substitute 24 barley grains for the 32 wheat grains of the text, according to the general convention of a 4:3 equivalence, for it to make sense. The weight of the original sterling pennies was 22½ troy grains, or 24 "Tower grains" if the Tower pound was divided in the same way as the troy pound. Regardless of which pound this text originally referred to, a (troy) ounce still equals 20×24 = 480(troy) grains, and a pound consists of 12×20×24 = 5760 grains.
Originally the troy pound was only "the pound of Pence, Spices, Confections, as of Electuaries
", and the merchants used different standards, which had to be compatible with those used abroad. One such standard, the avoirdupois pound, was later fixed officially at exactly 7000 troy grains. It consists of 16 avoirdupois ounces of 437½ troy grains each.
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
that is nominally based upon the mass of a single seed of a cereal
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...
. From the Bronze Age into the Renaissance the average masses of wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
and barley
Barley
Barley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
grains were part of the legal definition of units of mass. However, there is no evidence of any country ever having used actual seeds or cereal grains. Rather, expressions such as "thirty-two grains of wheat, taken from the middle of the ear" appear to have been ritualistic formulas, essentially the premodern equivalent of legal boilerplate
Boilerplate (text)
Boilerplate is any text that is or can be reused in new contexts or applications without being changed much from the original. Many computer programmers often use the term boilerplate code. A legal boilerplate is a standard provision in a contract....
.
The fundamental unit of the troy
Troy weight
Troy weight is a system of units of mass customarily used for precious metals, gemstones, and black powder.There are 12 troy ounces per troy pound, rather than the 16 ounces per pound found in the more common avoirdupois system. The troy ounce is 480 grains, compared with the avoirdupois ounce,...
, apothecary
Apothecaries' system
The apothecaries' system of weights is a historical system of mass units that were used by physicians and apothecaries for medical recipes, and also sometimes by scientists. The English version of the system is closely related with the English troy system of weights, the pound and grain being...
and avoirdupois
Avoirdupois
The avoirdupois system is a system of weights based on a pound of 16 ounces. It is the everyday system of weight used in the United States and is still widely used to varying degrees by many people in Canada, the United Kingdom, and some other former British colonies despite the official adoption...
systems, commonly known as the grain (or less commonly the barleycorn), is nominally based on the grain of barley. The fundamental unit of the pre-1527 English weight system for coins, known as Tower weights, was a different sort of grain known as the wheat-grain.
The grain is the only unit of mass measure common to the three traditional English mass and weight systems
English unit
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...
(avoirdupois
Avoirdupois
The avoirdupois system is a system of weights based on a pound of 16 ounces. It is the everyday system of weight used in the United States and is still widely used to varying degrees by many people in Canada, the United Kingdom, and some other former British colonies despite the official adoption...
, Apothecaries', troy
Troy weight
Troy weight is a system of units of mass customarily used for precious metals, gemstones, and black powder.There are 12 troy ounces per troy pound, rather than the 16 ounces per pound found in the more common avoirdupois system. The troy ounce is 480 grains, compared with the avoirdupois ounce,...
); the obsolete Tower grain was, by definition, exactly 45/64 of a troy grain.
Since 1958, the grain or troy grain (Symbol: gr) measure has been defined in terms of units of mass in the International System of Units
International System of Units
The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...
as precisely . However, the measure for pearl
Pearl
A pearl is a hard object produced within the soft tissue of a living shelled mollusk. Just like the shell of a mollusk, a pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other...
s and diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...
s - the pearl grain and the metric grain - are equal to of a (metric) carat, i.e. 50 mg (0.77 gr).
There are precisely 7,000 grains per avoirdupois
Avoirdupois
The avoirdupois system is a system of weights based on a pound of 16 ounces. It is the everyday system of weight used in the United States and is still widely used to varying degrees by many people in Canada, the United Kingdom, and some other former British colonies despite the official adoption...
pound in the Imperial and U.S. customary units
United States customary units
United States customary units are a system of measurements commonly used in the United States. Many U.S. units are virtually identical to their imperial counterparts, but the U.S. customary system developed from English units used in the British Empire before the system of imperial units was...
, and 5,760 grains in the Troy pound.
Usage in North America
Bullet
A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration...
s, gunpowder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
, smokeless powder
Smokeless powder
Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...
, and preformed gold foil; it is the measure used by the balances used in handloading
Handloading
Handloading or reloading is the process of loading firearm cartridges or shotgun shells by assembling the individual components , rather than purchasing completely assembled, factory-loaded cartridges...
; bullets are measured in increments of one grain, gunpowder in increments of 0.1 grains. Moreover, the grain is used to weigh fencing
Fencing
Fencing, which is also known as modern fencing to distinguish it from historical fencing, is a family of combat sports using bladed weapons.Fencing is one of four sports which have been featured at every one of the modern Olympic Games...
equipment, including the foil. In archery
Archery
Archery is the art, practice, or skill of propelling arrows with the use of a bow, from Latin arcus. Archery has historically been used for hunting and combat; in modern times, however, its main use is that of a recreational activity...
, the grain is used to weigh arrows and arrow parts.
The grain is the most common unit used to measure the hardness of water. In particular it is used to quantitively describe the abundance of calcium Ca2+ and magnesium Mg2+ minerals in water. Typically, the measure is noted in Grains per Gallon
Grains per Gallon
Grain per gallon is a unit of water hardness defined as 1 grain of calcium carbonate dissolved in 1 US gallon of water . It translates into 1 part in about 58,000 parts of water or 17.1 parts per million...
(GPG). Water, untreated, typically can measure up to 100 gpg. This measure is critical to setting accurately the resin cation bead regeneration cycle periodicity of both sodium chloride brine and potassium chloride brine flushed water softeners.
Medical prescription
A prescription is a health-care program implemented by a physician or other medical practitioner in the form of instructions that govern the plan of care for an individual patient. Prescriptions may include orders to be performed by a patient, caretaker, nurse, pharmacist or other therapist....
s, usually via the abbreviation "gr." For example, a regular tablet of aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...
is sometimes referred to as "five grain aspirin," or 325 mg. Grains are commonly used for medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
s that have been included in the United States Pharmacopeia for many decades, such as codeine
Codeine
Codeine or 3-methylmorphine is an opiate used for its analgesic, antitussive, and antidiarrheal properties...
, opium
Opium
Opium is the dried latex obtained from the opium poppy . Opium contains up to 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. The latex also includes codeine and non-narcotic alkaloids such as papaverine, thebaine and noscapine...
and phenobarbital
Phenobarbital
Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...
combinations. For example, a prescription for tablets containing 325 mg of aspirin and 30 mg of codeine (brand name is Empirin with codeine), is written thus: "ASA gr. v c cod. gr. ss tablets," where "ASA" is short for aspirin (AcetylSalicylic Acid), "v" is the roman numeral for five, "c" is the abbreviation for "with" and "ss" stands for one-half. Likewise, a prescription for B&O Supprettes #15A, which is a compound medication containing belladonna alkaloid
Alkaloid
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...
s and opium
Opium
Opium is the dried latex obtained from the opium poppy . Opium contains up to 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. The latex also includes codeine and non-narcotic alkaloids such as papaverine, thebaine and noscapine...
, may be written: "Belladonna gr. 1/4 c opium gr ss", as B&O Supprettes
B&O Supprettes
B&O Supprettes is the brand name for a prescription medication containing powdered opium and belladonna alkaloids in a suppository form. They are indicated for the treatment of moderate to severe pain from urethral spasm, and for extending the interval between injections of opiates...
#15A contain 16.2 mg (1/4 grain) of powdered belladonna and 30 mg (1/2 grain) of opium. Similarly, a prescription for 60 mg (1 grain) of phenobarbital is often written: "Phenobarb. gr. i". Formulations of these older medications (e.g., Donnatal
Donnatal
Donnatal is a proprietary combination medication for the treatment of intestinal cramping due to various causes, often administered as part of a GI Cocktail. It is classed as an anticholinergic antispasmodic drug. Donnatal is marketed by PBM Pharmaceuticals. It is available as tablets, capsules,...
, Phenobarbital
Phenobarbital
Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...
, etc.), often use grains on the product label along with the metric equivalent. For example, Extended-Release Donnatal tablets contain (approximately 48.6 mg) of phenobarbital. Given the potential error in mistaking the abbreviations for "grains" and "grams" (gr and g, respectively), and for consistency with other medical orders, metric units are preferred to avoirdupois
Avoirdupois
The avoirdupois system is a system of weights based on a pound of 16 ounces. It is the everyday system of weight used in the United States and is still widely used to varying degrees by many people in Canada, the United Kingdom, and some other former British colonies despite the official adoption...
or apothecary
Apothecary
Apothecary is a historical name for a medical professional who formulates and dispenses materia medica to physicians, surgeons and patients — a role now served by a pharmacist and some caregivers....
units; hence, the use of grains in the medical profession is rapidly becoming outmoded.
History
| carob seed | ~200 mg |
| barley grain | ~65 mg |
| wheat grain | ~50 mg |
At least since antiquity
Classical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...
, grains of wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
or barley
Barley
Barley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
were used by Mediterranean traders
History of the Mediterranean region
The history of the Mediterranean region is the history of the interaction of the cultures and people of the lands surrounding the Mediterranean Sea —the central superhighway of transport, trade and cultural exchange between diverse peoples...
to define units of mass; along with other seeds, especially those of the carob tree. According to a longstanding tradition, 1 carat (the mass of a carob seed) was equivalent to the weight of 4 wheat grains or 3 barleycorns. But since the weights of these seeds are highly variable, especially that of the cereals as a function of moisture, this is a convention more than an absolute law.
The history of the modern grain can be traced back to a royal decree in 13th century England:
The traditional reading of this text is that it refers to the troy pound, and that the reference to sterling pennies is purely symbolic. According to a more recent reading, however, the pound in question is the Tower pound, and it talks about the actual mass of real sterling pennies. The Tower pound, abolished in 1527, consisted of 12 ounces like the troy pound, but was lighter. In any case, with both readings one needs to substitute 24 barley grains for the 32 wheat grains of the text, according to the general convention of a 4:3 equivalence, for it to make sense. The weight of the original sterling pennies was 22½ troy grains, or 24 "Tower grains" if the Tower pound was divided in the same way as the troy pound. Regardless of which pound this text originally referred to, a (troy) ounce still equals 20×24 = 480(troy) grains, and a pound consists of 12×20×24 = 5760 grains.
Originally the troy pound was only "the pound of Pence, Spices, Confections, as of Electuaries
Electuary
An electuary is a medicinal paste composed of powders, or other medical ingredients, incorporated with sweeteners to hide the taste, like syrup, honey, jam, etc., for the purposes of oral consumption....
", and the merchants used different standards, which had to be compatible with those used abroad. One such standard, the avoirdupois pound, was later fixed officially at exactly 7000 troy grains. It consists of 16 avoirdupois ounces of 437½ troy grains each.