The basic unit of weight in the British system is the grain - originally
based on the
weight of a grain of barley (but note that money was based on the grain of
wheat - and that three grains of barley weigh the same as four of wheat).
This grain is the troy grain - there is no other weight of the same name.
The weight of one grain is constant throughout the many different systems of
British weights. As you will see below, the ounce and pound are anything but
contstant, but have altered to meet circumstances over a period of over a
thousand years.
The avoirdupois pound is the pound in general use today. As its name
implies, it was intended to be used for weighing heavy goods. This pound
is of 7000 grains, and is split into 16 ounces (each, therefore of 437.5
grains). Each ounce is divided into 16 drams.
Avoirdupois Weights
16 drams= 1 ounce
16 ounces= 1 pound
7 pounds= 1 clove
14 pounds= 1 stone
28 pounds= 1 tod
112 pounds= 1 hundredweight
364 pounds= 1 sack
2240 pounds= 1 ton
2 stones= 1 quarter
4 quarters= 1 hundredweight
20 hundredweight= 1 ton
The sack is not in common use. There was a 'Butchers
stone' of 8lb until the end of 1939.
The Troy pound was of 5760 grains, and was divided into 12 ounces, so
a troy pound is lighter than an avoirdupois pound, but a troy ounce (at 480
grains) weighs more than an avoirdupois ounce. The troy pound was declared
illegal in 1878, but the troy ounce continues in use today for weighing gold.
The troy ounce is split into 480 grains, and you will see 1/2 ounce weights
marked both '240 grains' and '0.5oz'. However, the apothecaries
system also has an ounce weighing 480 grains, being divided into 8 drams
(sometimes spelled drachms) of 60 grains, each dram being split into 3
scruples, of 20 grains. To make things more fun, a 2 dram weight would be
marked '3ij' - I think that '3' means 'scruples' (there being 3 to the
dram), and the 'ij' being an old-fashioned way of quoting the Roman numeral
'ii'. It doesn't end there - there are 20 penny-weights to the troy
ounce, so the 1/2 ounce weight mentioned above could also be marked as '3iv'
or '10dwt'.
Troy & apothecaries weights
1 ounce= 480 grains
1 ounce= 24 scruples
1 ounce= 20 pennyweights
1 ounce= 8 drams
The wool pound was of 6992 grains, and was (of course) used for
weighing wool. The clove, stone and tod mentioned above were also used.
The tower pound was used for weighing coins, and was of 5400 grains.
I believe the name tower comes from Tower Hill, the site of the royal
mint. This number of grains comes from the traditional weight of an English
silver penny of 22 1/2 grains (Troy, or grains of barley - the same as
30 grains of wheat), and 240 pennies to the pound. The tower pound was abolished
in 1527.
The London pound, or libra mercatoria (trade pound) was 7200
grains (i.e. 15 troy ounces). This died out around the middle of the 14th
century. One London stone was of 12 1/2 London pounds.
Dram
An ancient unit of weight, also a Greek coin. It is believed to have originally
meant the amount which one could hold in one's hand.
16 drams = 1 ounce avoirdupois
8 drams = 1 ounce apothecaries
1 dram (avoirdupois) = 27.34375 grains
1 dram (avoirdupois)= 1.772 grams
1 dram (apothecaries) = 60 grains
Therefore:
1 dram apothecaries = 2.194286 drams avoirdupois
Imperial System
A British system developed and refined from the earlier Roman systems used
in Britain during the middle ages.
In 1824 the troy pound was defined or confirmed.
In 1863 the Imperial or avoirdupois pound was redefined as 0.45359237 kilograms.
20 stones avoirdupois = 1 ton avoirdupois
14 pounds avoirdupois = 1 stone avoirdupois
16 ounces avoirdupois = 1 pound avoirdupois
1 ounce avoirdupois = 28.349523 grams approx.
1 pound avoirdupois = 453.59237 grams
1 ton avoirdupois = 2240 pounds avoirdupois
Troy
A system historically used for measuring the weight of drugs, precious metals
and gemstones. The name comes from the French city of Troyes.
480 grains = 1 ounce troy
31.1035 grams = 1 ounce troy
12 troy ounces = 1 troy pound
20 pennyweights (dwt) = 1 ounce troy
1 pound = 373.242 grams
1 pound = 5760 grains
Pennyweight
The pennyweight was the weight of a silver penny in medieval England. When
pennies were introduced in England in the 8th century, their original weight
is believed to have been 24 grains. This was gradually reduced, in at least
thirteen stages until it reached 7.27 grains by 1816.
According to one knowledgeable source, the pennyweight was introduced by Henry
III in 1266 as the weight of 32 grains of wheat. We believe this may simply
have been clarifying and codifying an existing standard.
24 grains = 1 pennyweight
20 pennyweights = 1 ounce troy
240 pennyweights = 1 pound troy
It is no coincidence that there were 240 pennies to the English pound , and
240 silver pennies were equivalent to a pound of silver, or that the word sterling
applies both to the english pound and to a standard purity of silver.
based on the
weight of a grain of barley (but note that money was based on the grain of
wheat - and that three grains of barley weigh the same as four of wheat).
This grain is the troy grain - there is no other weight of the same name.
The weight of one grain is constant throughout the many different systems of
British weights. As you will see below, the ounce and pound are anything but
contstant, but have altered to meet circumstances over a period of over a
thousand years.
The avoirdupois pound is the pound in general use today. As its name
implies, it was intended to be used for weighing heavy goods. This pound
is of 7000 grains, and is split into 16 ounces (each, therefore of 437.5
grains). Each ounce is divided into 16 drams.
Avoirdupois Weights
16 drams= 1 ounce
16 ounces= 1 pound
7 pounds= 1 clove
14 pounds= 1 stone
28 pounds= 1 tod
112 pounds= 1 hundredweight
364 pounds= 1 sack
2240 pounds= 1 ton
2 stones= 1 quarter
4 quarters= 1 hundredweight
20 hundredweight= 1 ton
The sack is not in common use. There was a 'Butchers
stone' of 8lb until the end of 1939.
The Troy pound was of 5760 grains, and was divided into 12 ounces, so
a troy pound is lighter than an avoirdupois pound, but a troy ounce (at 480
grains) weighs more than an avoirdupois ounce. The troy pound was declared
illegal in 1878, but the troy ounce continues in use today for weighing gold.
The troy ounce is split into 480 grains, and you will see 1/2 ounce weights
marked both '240 grains' and '0.5oz'. However, the apothecaries
system also has an ounce weighing 480 grains, being divided into 8 drams
(sometimes spelled drachms) of 60 grains, each dram being split into 3
scruples, of 20 grains. To make things more fun, a 2 dram weight would be
marked '3ij' - I think that '3' means 'scruples' (there being 3 to the
dram), and the 'ij' being an old-fashioned way of quoting the Roman numeral
'ii'. It doesn't end there - there are 20 penny-weights to the troy
ounce, so the 1/2 ounce weight mentioned above could also be marked as '3iv'
or '10dwt'.
Troy & apothecaries weights
1 ounce= 480 grains
1 ounce= 24 scruples
1 ounce= 20 pennyweights
1 ounce= 8 drams
The wool pound was of 6992 grains, and was (of course) used for
weighing wool. The clove, stone and tod mentioned above were also used.
The tower pound was used for weighing coins, and was of 5400 grains.
I believe the name tower comes from Tower Hill, the site of the royal
mint. This number of grains comes from the traditional weight of an English
silver penny of 22 1/2 grains (Troy, or grains of barley - the same as
30 grains of wheat), and 240 pennies to the pound. The tower pound was abolished
in 1527.
The London pound, or libra mercatoria (trade pound) was 7200
grains (i.e. 15 troy ounces). This died out around the middle of the 14th
century. One London stone was of 12 1/2 London pounds.
Dram
An ancient unit of weight, also a Greek coin. It is believed to have originally
meant the amount which one could hold in one's hand.
16 drams = 1 ounce avoirdupois
8 drams = 1 ounce apothecaries
1 dram (avoirdupois) = 27.34375 grains
1 dram (avoirdupois)= 1.772 grams
1 dram (apothecaries) = 60 grains
Therefore:
1 dram apothecaries = 2.194286 drams avoirdupois
Imperial System
A British system developed and refined from the earlier Roman systems used
in Britain during the middle ages.
In 1824 the troy pound was defined or confirmed.
In 1863 the Imperial or avoirdupois pound was redefined as 0.45359237 kilograms.
20 stones avoirdupois = 1 ton avoirdupois
14 pounds avoirdupois = 1 stone avoirdupois
16 ounces avoirdupois = 1 pound avoirdupois
1 ounce avoirdupois = 28.349523 grams approx.
1 pound avoirdupois = 453.59237 grams
1 ton avoirdupois = 2240 pounds avoirdupois
Troy
A system historically used for measuring the weight of drugs, precious metals
and gemstones. The name comes from the French city of Troyes.
480 grains = 1 ounce troy
31.1035 grams = 1 ounce troy
12 troy ounces = 1 troy pound
20 pennyweights (dwt) = 1 ounce troy
1 pound = 373.242 grams
1 pound = 5760 grains
Pennyweight
The pennyweight was the weight of a silver penny in medieval England. When
pennies were introduced in England in the 8th century, their original weight
is believed to have been 24 grains. This was gradually reduced, in at least
thirteen stages until it reached 7.27 grains by 1816.
According to one knowledgeable source, the pennyweight was introduced by Henry
III in 1266 as the weight of 32 grains of wheat. We believe this may simply
have been clarifying and codifying an existing standard.
24 grains = 1 pennyweight
20 pennyweights = 1 ounce troy
240 pennyweights = 1 pound troy
It is no coincidence that there were 240 pennies to the English pound , and
240 silver pennies were equivalent to a pound of silver, or that the word sterling
applies both to the english pound and to a standard purity of silver.
