Conversion from 50 Hundredweights to Drams

Information about the Hundredweight (cwt)

The hundredweight is a unit of mass whose value depends on which side of the Atlantic you are standing. The imperial or long hundredweight is 112 pounds, about 50.802 kilograms. The US or short hundredweight is 100 pounds, about 45.359 kilograms. Its symbol is cwt, from the Latin centum and the English weight.

The name promises a hundred and the imperial version delivers a hundred and twelve, which looks like an error until the arithmetic behind it is seen. Twenty hundredweight make a long ton of 2240 pounds, and a hundredweight is eight stone of fourteen pounds each. The chain of halvings and doublings that runs from the pound to the ton only closes neatly if the intermediate unit is 112, so the number is a consequence of the system rather than a mistake in it.

Its working life was in bulk trade. Coal, cement, grain, potatoes and fertiliser moved by the hundredweight, and sack sizes were built around it: the standard British coal sack held one hundredweight, which is why a coal merchant's cart was rated in a number of hundredweight rather than in tons. Vans and light trucks were once classified the same way, and the phrase survives in some vehicle names.

In the United States the short hundredweight is still used in agricultural markets, where livestock, grain and milk prices are quoted per hundredweight rather than per pound or per ton. Elsewhere the unit has largely given way to the tonne and the kilogram, and its main modern role is to make old records intelligible.

Continental Europe kept a cousin of it under a different name. The quintal, from the Arabic qintar by way of medieval Latin, served the same purpose in French, Spanish, Italian and Portuguese trade, and when the metric system arrived it was simply redefined as a round 100 kilograms. That metric quintal is still the unit in which grain harvests are reported across much of southern Europe, Latin America and India, and it sits close enough to the imperial hundredweight of 50.8 kilograms that old and new figures can look deceptively similar. The parallel is instructive: both units survived because a sack a strong worker could handle is a more natural quantity than any round metric mass.

One imperial hundredweight equals 112 pounds, about 50.802 kilograms, or 8 stone.

Information about the Dram (dr)

The dram is a unit of mass equal to one sixteenth of an avoirdupois ounce, or about 1.7718 grams. Its symbol is dr. There are 256 drams in a pound and 27.34375 grains in a dram, a set of numbers that shows how far the avoirdupois system drifted from tidy arithmetic.

The name descends from the Greek drachma through Latin and Old French, and the same root gives the modern currency of Armenia and the historical coin of Athens. The apothecaries' dram was a different and larger unit, one eighth of a troy ounce or 3.888 grams, and pharmacists used it until the twentieth century. Recipes and old medical texts therefore need reading with care, since an unqualified dram may be either.

Modern survival is narrow but real. Shotgun shells are the best-known case: the dram equivalent printed on a box of cartridges is a legacy figure describing the propellant charge in terms of the black powder that would have produced the same velocity, not the actual weight of modern smokeless powder. American recipes occasionally call for drams, and the unit persists in some descriptions of small hardware and fishing weights.

For everyday purposes the dram is now a curiosity, kept alive by its appearance on packaging and in older texts rather than by any working need. Where precision matters the same quantity is stated in grams, and where tradition matters the word survives without its arithmetic being examined too closely.

Two other drams complicate the picture. The apothecaries' dram, used in pharmacy until the twentieth century, was one eighth of a troy ounce and weighed about 3.888 grams, more than twice the avoirdupois dram described here. The fluid dram is a measure of volume rather than mass, one eighth of a fluid ounce, and it still appears on the graduations of old medicine glasses and on some American pharmacy equipment. A recipe or a formula written before the metric era therefore has to be read with its system identified first, because the same word can mean two different masses and a volume, and nothing in the notation distinguishes them.

One dram equals about 1.7718 grams, one sixteenth of an ounce, or 27.34375 grains.