Dram (unit)
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The dram (archaic spelling drachm; apothecary symbol ℨ) was historically both a coin and a weight. It refers both to a unit of mass in the Apothecaries' system of weights and a unit of volume in the imperial system. The latter unit is more correctly called a fluid dram or, in contraction, fluidram.
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[edit] Ancient unit of mass
- The Greek drachm is a weight of 1⁄100 Greek mine, or about 4.37 grams.
- The Roman drachm is a weight of 1⁄96 Roman pounds, or about 3.41 grams.
Greek and Roman drachm are related by the approximate ratio 32 : 25.
The Ottoman dirhem is based on the Sassanian drachm, which is itself based on the Roman dram/drachm. Modern Armenian drams, the currency of the Republic of Armenia, share this origin.
[edit] Modern unit of mass
In the avoirdupois system, the dram is the mass of 1⁄256 pound or 1⁄16 ounce. So the dram weighs 875⁄32 grains or exactly 1.771 845 195 312 5 grams.[1]
The dram is 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 is equal to 3 scruples (℈) or 60 grains (G). Thus, it is equal to exactly 3.887 9346 grams.
[edit] Unit of 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 United States and
- 3.551 632 812 500 0 mL in the Commonwealth and Ireland.
In the United Kingdom, a teaspoon was originally (from c. 1660) defined as one fluid dram. Circa 1710 the East India Company began importing tea direct to England, at which point the price of tea came down, and the size of teaspoons (and teacups) went up to 1/3 tablespoon or 1/6 of an ounce, often rounded, for the sake of convenience, to one fluid dram and half (now 5 mL).
"Dram" is also used as a measure of the powder charge in a shotgun shell.
Dram is also used informally to mean a small amount of liquid, especially Scotch whisky. In this case the "dram" will usually be 30 ml - see Alcoholic spirits measures.
[edit] References
- ^ Zupko, Ronald Edward (1985). A dictionary of weights and measures for the British Isles: the Middle Ages to the twentieth century. American Philosophical Society. p. 113. ISBN 978-0-87169-168-2. http://books.google.com/books?id=0l_k-XMIiQIC&pg=PA113. Retrieved 24 December 2011.
[edit] External links
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Look up dram in Wiktionary, the free dictionary. |
