| |
Gram
A gram or gramme is a standard metric unit of
weight. There are 1000 grams per kilogram.
In 1960, the ISO confirmed the IS unit system which was based upon the
existing MKS (Metres, Kilograms, and Seconds) system.
The kilogram was defined as the weight of the International Prototype made
of platinum and iridium which is held at the International Bureau of Weights
and Measures in Sèvres in France.
Grain
An ancient unit, which was originally based on
the weight of a grain of wheat. The grain is the smallest unit of weight in
the avoirdupois, troy, and apothecaries systems. Surprisingly it is
identical in all three systems.
4 grains = 1 carat
24 grains =1 pennyweight
480 grains = 1 troy ounce
5760 grains = 1 troy pound
437.5 grains = 1 ounce avoirdupois
7000 grains = 1 pound avoirdupois
1 grain = 0.0648 grams (0.06479891)
15.432 grains = 1 gram
Although we have stated above that the grain weighted the same in both of
the above systems, there were at least two different grains. The troy system
used the supposed weight of the barley grain, whereas the wheat grain was
also used as a standard of weight. There were three barley grains to four
wheat grains.
Momme
A unit of weight previously used in Japan to
weigh pearls.
75 grains = momme
18.75 carats = 1 momme
3.75 grams = 1 momme
Dram
or Drachm
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.
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.
Tolas
The tola is an old Indian unit of weight. It
was the equivalent of the silver rupee issued by the British East India
Company, at 180 grains, which equate to 11.6638038 grams, so:-
180 grains = 1 tola
11.66 grams = 1 tola
0.375 troy ounces = 1 tola
Tower
Pound
The tower pound was also used for weighing
coins, and possibly precious metals, until 1527. The tower pound weighed
5400 grains, equal to 225 pennyweights, making 11.25 troy ounces per tower
pound. One source we have seen believes that the tower pound was named after
Tower Hill, the site of the Royal Mint, but we believe it is from the Tower
of London, from which Tower Hill also got its name.
From about the tenth century, English silver pennies weighed 22.5 grains,
and there were therefore 240 pennies per Tower pound. The Tower pound
appears to have been the same as the previous Saxon pound, and simply
underwent a change of name at some stage.
|
