Getting a Grip on Grains and Karats
By
August 22, 2012
August 22, 2012
Newcomers to numismatics
can become a little perplexed when measurements from mankind’s past raise their
heads. The carat and ounce stubbornly lurk amidst the bullion fraternity. And
the grain possesses a longevity that is astounding.
These terms hark back to a day and age when merchants engaged in trade required ways of measuring weight and/or volume and/or size that were agreed upon by all participants. This was true whether a deal was undertaken in the local bazaar or between nations. It was essential when the participants did not share a common language.
Grains of Truth
When it came to weight, all major ancient markets throughout Europe and the Middle East agreed there would be one universal measure: the grain. Traditionally, this was the weight of a dried barleycorn taken from the middle of an ear. It may seem odd, but it was remarkably consistent weight.
These terms hark back to a day and age when merchants engaged in trade required ways of measuring weight and/or volume and/or size that were agreed upon by all participants. This was true whether a deal was undertaken in the local bazaar or between nations. It was essential when the participants did not share a common language.
Grains of Truth
When it came to weight, all major ancient markets throughout Europe and the Middle East agreed there would be one universal measure: the grain. Traditionally, this was the weight of a dried barleycorn taken from the middle of an ear. It may seem odd, but it was remarkably consistent weight.
The grains of hulled
barley proved ideal for the purpose. The crop had been cultivated widely in the
Near and Middle East from at least 8500 B.C.E. It became widespread through
trade and proved extremely adaptable, growing happily under both cool and
tropical conditions. Importantly, it provided both bread and beer. It became
such a dominant staple that Jared Diamond argues that its availability was a
principal factor in the endurance and dominance of Eurasian civilizations for
13,000 years.
As so it was that the dried barleycorn became the common international weight standard. It happened quickly. It was adopted for weighing, among other things, precious metals and the coins made from them.
And it also happened very early. One of the first written references occurs in the remarkable Hindu Sanskrit text, Manusmriti, or The Laws of Manu, that dates from perhaps 200 B.C.E. It notes that, “Six white mustard seeds equal one medium sized barleycorn, and three barleycorns make one berry; five berries make a bean, and sixteen beans a gold piece.”
Of course the opportunities for sharp practice when selecting particular grains for weighing were manifold. There are frequent references in the Old Testament that are elaborated in the Talmud: Do not have two differing weights in your bag – one heavy, one light. Do not have two differing measures in your house – one large, one small. You must have accurate and honest weights and measures, so that you may live long in the land the LORD your God is giving you. For the LORD your God detests anyone who does these things, anyone who deals dishonestly. Deuteronomy 25:13-16 Just balances, just weights, a just ephah [measure], and a just hin [another measure], shall ye have: I am the Lord your God, which brought you out of the land of Egypt. Leviticus 19:36 The Lord abhors dishonest scales, but accurate weights are His delight. Proverbs 11:1 By the end of the Bronze Age, hulled barley had made it to England. It brought with it the penchant for using cereal grains as a weight – and a linear – measure. Philip Grierson notes in the laws of King Ethelbert of Kent, which date from the first decade of the 17th century: … we meet with our earliest units, one of length and two of weight. Those of weight, which are used to define quantities of gold required in compensation for injuries and offences, are the Sceatta, which must be understood as meaning a Grain [barleycorn] of gold and not as has usually been assumed, a silver coin, and its multiple the Scilling [shilling] of twenty sceatta.
Numbered, Weighed and Divided
When King Offa of Mercia assumed Charlemagne’s notion of slicing a pound of silver into 240 pennies, around about 780 C.E., he used a pound of 5,400 grains, giving each of his coins a weight of 22.5 grains. Eventually this 5,400 grain pound would be taken by William Conqueror as the norm for the coin of his new realm. He placed the standard silver pound in his new tower in London, where it became known as the Tower Pound. It would remain the standard for English coin weight until 1527.
All of it may seem quite straightforward, but it isn’t. For starters, a preference evolved for using the smaller wheat grain as a weight measure. Professor Harold Miskimin gives the weight of an average barleycorn as 0.0637 g. Wheat comes in at about 0.05 g. A long-standing tradition developed that 4 wheat grains were equivalent to 3 barleycorns.
The wheat grain measure was well established in England by the 13th century when the Assize of Weights and Measures declared, “by consent of the whole realm the king’s measure was made, so that an English penny, which is called the sterling, round without clipping, shall weigh thirty-two grains of wheat dry in the midst of the ear,” i.e. 24 barley grains.
Clearly it is important to be aware which grain is being referred to in any historic discussion. It is not always evident. Equally so, it is important to be alert to the type of pound being referred to. Not all pounds were created equal with many different versions in use in medieval Europe. The Carolingian pound of Charlemagne, which he carved into 240 deniers, weighed in at 7,680 grains, but was he using wheat or barley grains?
Fine Tuning
Commonly these days, mints describe precious metal coins, be they commemoratives or bullion pieces, as being of a specific millesimal fineness. This system describes their purity as so many parts per thousand. For example, a Walking Liberty half dollar consists of 90.0 percent silver, i.e. it contains 900 parts of silver for every 1,000 parts of alloy. This can be expressed as .900 fine, given that pure or fine silver contains 1,000 parts of silver in every 1,000 and is hence 1.000 fine. Sometimes the fineness is stated as simply 900 fine with no decimal point, or even 90.0.
Expressing metal purity in this way provides an alternative to the much older karat carat (or karat) system. This was/is commonly used for gold with the purity (fineness) expressed as a fraction of 24.
British sovereigns were struck in 22 karat alloy, i.e. each consisted of 91.7 percent pure gold and 8.3 percent copper (or silver). Similarly, 18 karat gold is 75 percent gold, 9 karat gold is 37.5 percent gold and, of course, 24 karat gold is 100 percent gold – although 99.9 percent and even 99.5 percent is what generally cuts the mustard.
The karat is another unit of weight derived from the practice of using seeds as a universal weight standard. In this case, the seed was that of the carob tree, Ceratonia siliqua, found throughout the Mediterranean and Middle East. In late Roman times, a pure gold solidus that weighed the same as 24 carob seeds was taken as being of full weight. It is this measure that led to the carat (karat) scale a few centuries down the track. In general, it is not used for silver or platinum.
In England, the weight of a carob seed was set equivalent to 4 grains (i.e. 0.25 g today if my arithmetic is correct).
The first legal definition of “sterling silver” comes in England from an Act of Edward I in 1275. It specified that 12 ounces of coinage silver should contain 11 ounces 2-1/4 pennyweights of silver and 17-3/4 pennyweights of alloy, where a pennyweight now weighed 24 grains. This subsequently became the standard (=sterling) for silver to be used for coin and plate throughout the kingdom. A hallmark consisting of a lion passant gardant denoted plate as sterling. However, there was a problem. It came to a head four centuries down the track.
In 1697 during the Great Recoinage of William III, Parliament passed a further Act to replace sterling as the obligatory standard for items such as silver plate to allow them to be made of “Britannia silver” – .958 fine. The notion was that this higher standard for plate would provide less incentive to pop newly issued sterling coins in the melt pot as had become commonplace over the years. Britannia silver was distinguished with a hallmark consisting of “the figure of a woman commonly called Britannia.” And today the Royal Mint strikes its silver bullion Britannias in Britannia silver.
As for Troy ounces, that is another story and one that is seldom told correctly.
Source: http://www.numismaster.com/ta/numis/Article.jsp?ad=article&ArticleId=25678
As so it was that the dried barleycorn became the common international weight standard. It happened quickly. It was adopted for weighing, among other things, precious metals and the coins made from them.
And it also happened very early. One of the first written references occurs in the remarkable Hindu Sanskrit text, Manusmriti, or The Laws of Manu, that dates from perhaps 200 B.C.E. It notes that, “Six white mustard seeds equal one medium sized barleycorn, and three barleycorns make one berry; five berries make a bean, and sixteen beans a gold piece.”
Of course the opportunities for sharp practice when selecting particular grains for weighing were manifold. There are frequent references in the Old Testament that are elaborated in the Talmud: Do not have two differing weights in your bag – one heavy, one light. Do not have two differing measures in your house – one large, one small. You must have accurate and honest weights and measures, so that you may live long in the land the LORD your God is giving you. For the LORD your God detests anyone who does these things, anyone who deals dishonestly. Deuteronomy 25:13-16 Just balances, just weights, a just ephah [measure], and a just hin [another measure], shall ye have: I am the Lord your God, which brought you out of the land of Egypt. Leviticus 19:36 The Lord abhors dishonest scales, but accurate weights are His delight. Proverbs 11:1 By the end of the Bronze Age, hulled barley had made it to England. It brought with it the penchant for using cereal grains as a weight – and a linear – measure. Philip Grierson notes in the laws of King Ethelbert of Kent, which date from the first decade of the 17th century: … we meet with our earliest units, one of length and two of weight. Those of weight, which are used to define quantities of gold required in compensation for injuries and offences, are the Sceatta, which must be understood as meaning a Grain [barleycorn] of gold and not as has usually been assumed, a silver coin, and its multiple the Scilling [shilling] of twenty sceatta.
Numbered, Weighed and Divided
When King Offa of Mercia assumed Charlemagne’s notion of slicing a pound of silver into 240 pennies, around about 780 C.E., he used a pound of 5,400 grains, giving each of his coins a weight of 22.5 grains. Eventually this 5,400 grain pound would be taken by William Conqueror as the norm for the coin of his new realm. He placed the standard silver pound in his new tower in London, where it became known as the Tower Pound. It would remain the standard for English coin weight until 1527.
All of it may seem quite straightforward, but it isn’t. For starters, a preference evolved for using the smaller wheat grain as a weight measure. Professor Harold Miskimin gives the weight of an average barleycorn as 0.0637 g. Wheat comes in at about 0.05 g. A long-standing tradition developed that 4 wheat grains were equivalent to 3 barleycorns.
The wheat grain measure was well established in England by the 13th century when the Assize of Weights and Measures declared, “by consent of the whole realm the king’s measure was made, so that an English penny, which is called the sterling, round without clipping, shall weigh thirty-two grains of wheat dry in the midst of the ear,” i.e. 24 barley grains.
Clearly it is important to be aware which grain is being referred to in any historic discussion. It is not always evident. Equally so, it is important to be alert to the type of pound being referred to. Not all pounds were created equal with many different versions in use in medieval Europe. The Carolingian pound of Charlemagne, which he carved into 240 deniers, weighed in at 7,680 grains, but was he using wheat or barley grains?
Fine Tuning
Commonly these days, mints describe precious metal coins, be they commemoratives or bullion pieces, as being of a specific millesimal fineness. This system describes their purity as so many parts per thousand. For example, a Walking Liberty half dollar consists of 90.0 percent silver, i.e. it contains 900 parts of silver for every 1,000 parts of alloy. This can be expressed as .900 fine, given that pure or fine silver contains 1,000 parts of silver in every 1,000 and is hence 1.000 fine. Sometimes the fineness is stated as simply 900 fine with no decimal point, or even 90.0.
Expressing metal purity in this way provides an alternative to the much older karat carat (or karat) system. This was/is commonly used for gold with the purity (fineness) expressed as a fraction of 24.
British sovereigns were struck in 22 karat alloy, i.e. each consisted of 91.7 percent pure gold and 8.3 percent copper (or silver). Similarly, 18 karat gold is 75 percent gold, 9 karat gold is 37.5 percent gold and, of course, 24 karat gold is 100 percent gold – although 99.9 percent and even 99.5 percent is what generally cuts the mustard.
The karat is another unit of weight derived from the practice of using seeds as a universal weight standard. In this case, the seed was that of the carob tree, Ceratonia siliqua, found throughout the Mediterranean and Middle East. In late Roman times, a pure gold solidus that weighed the same as 24 carob seeds was taken as being of full weight. It is this measure that led to the carat (karat) scale a few centuries down the track. In general, it is not used for silver or platinum.
In England, the weight of a carob seed was set equivalent to 4 grains (i.e. 0.25 g today if my arithmetic is correct).
The first legal definition of “sterling silver” comes in England from an Act of Edward I in 1275. It specified that 12 ounces of coinage silver should contain 11 ounces 2-1/4 pennyweights of silver and 17-3/4 pennyweights of alloy, where a pennyweight now weighed 24 grains. This subsequently became the standard (=sterling) for silver to be used for coin and plate throughout the kingdom. A hallmark consisting of a lion passant gardant denoted plate as sterling. However, there was a problem. It came to a head four centuries down the track.
In 1697 during the Great Recoinage of William III, Parliament passed a further Act to replace sterling as the obligatory standard for items such as silver plate to allow them to be made of “Britannia silver” – .958 fine. The notion was that this higher standard for plate would provide less incentive to pop newly issued sterling coins in the melt pot as had become commonplace over the years. Britannia silver was distinguished with a hallmark consisting of “the figure of a woman commonly called Britannia.” And today the Royal Mint strikes its silver bullion Britannias in Britannia silver.
As for Troy ounces, that is another story and one that is seldom told correctly.
