Convert from dram to libra [ancient Rome]

Unit Definition (dram)
The dram is a unit of weight in the traditional avoirdupois system, equal to 1/16 ounce or 1/256 pound. One dram equals about 1.7718 gram. The word dram comes from a Latin weight unit, the dragma, and derives ultimately from the Greek drachme, meaning a handful. The word is usually spelled "drachm" in Britain and "dram" in the United States, but both spellings are pronounced "dram." The avoirdupois dram is sometimes abbreviated dr. av. to distinguish it from the apothecaries' dram.

Unit Definition (libra [ancient Rome])
The libra [ancient Rome] is a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The Roman libra contained only 12 unciae (ounces) and was about 0.722 English pound. The word "libra" is sometimes used now for the kilogram, a much larger unit.