Dram (unit)
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Also see the article : Greek drachma.
The dram (American spelling) or drachm (British spelling) was historically both a coin and a weight.
Currently drachm or dram is both
- a small mass in the system of weights avoirdupois and
- a small unit of volume. This unit is called more correctly fluid dram or in contraction also fluidram.
[edit] Drachm (mass)
[edit] Ancient masses
- The Greek drachm was a weight of 1/100 Greek mine, which is about 4.37 grams.
- The Roman drachm was a weight of 1/96 Roman pounds, which is about 3.41 grams.
Greek and Roman drachm were related by the ratio 25 : 32.
[edit] Masses in the English-speaking world
The dram is the mass of 1/256 pound avoirdupois and 1/16 ounce. So the dram weighs 875 / 32 grains.
- 7 x 64.80000 / 256 = 1.771 875 000 000 0 gram : This is the conventional, however not the official value of the mass called dram.
- 7 x 64.79891 / 256 = 1.771 845 195 312 5 gram : This is the legal value, exactly 99.9983179012345679 % of the value above.
The dram (symbol: ʒ) was also the mass of 1/96 pound (℔) or 1/8 ounce (℥) in the apothecaries' system that survived until the middle of the 20th century in English-speaking countries. It was equal to 3 scruples (℈) or 60 grains (G). Thus, it was equal to 3.888 grams (in the SI).
[edit] Drachm (volume)
The fluid dram is defined as 1/8 of a fluid ounce, which means it is exactly equal to
- 3.696 691 195 312 5 mL in the U.S. and
- 3.551 632 812 500 0 mL in most other Anglo-Saxon countries.
Dram is also used informally to mean a small amount of liquid, especially Scotch whisky.
[edit] See also
