Apothecaries' Drams to Ounces (ʒ to oz)

1 apothecaries' dram equals 0.1371428571 ounces (rounded).

1 apothecaries' dram = 0.1371428571 ounces

How to convert apothecaries' drams to ounces

To convert apothecaries' drams to ounces, multiply the number of apothecaries' drams by 0.1371428571. The factor is rounded to 10 significant digits. To go the other way, multiply ounces by 7.291666667 (rounded).

ounces = apothecaries' drams × 0.1371428571

Example: 10 apothecaries' drams = 1.371428571 ounces.

About these units

Apothecaries' Dram (ʒ)

Troy & apothecaries'Historical unit (no longer in standard use)

60 grains or 3 scruples (3.888 g). Used in old medical prescriptions.

Greek drachma coins left their mark on this unit, which the apothecaries' tables spelled drachm or dram and abbreviated with a curled symbol. It was worth 60 grains, or three scruples, or about 3.89 grams, and eight of them filled an apothecaries' ounce.

Doctors wrote it into Latin prescriptions with Roman numerals, so three drams appeared as the symbol followed by iij and half a dram as the symbol followed by ss, short for semis. Until about 1900 most prescriptions were written this way.

Do not confuse it with the avoirdupois dram, which is much smaller than this one, and with the fluid dram used for liquids. An Irish pharmacopoeia of 1850 even proposed an avoirdupois-based version of about 54.68 grains. British law ended the apothecaries' system in the 1970s, and modern doses are given in grams or milligrams.

1 apothecaries' dram = 0.0038879346 kilograms (exactly).

Sources: Wikipedia: Apothecaries' system; Wikipedia: Troy weight

Ounce (oz)

US & ImperialCurrent unit

One sixteenth of a pound, exactly 28.349523125 g. Used for food, mail and consumer goods in the US and UK.

A twelfth part is what ounce originally meant. It comes from the Roman uncia, one twelfth of the Roman pound, a word that also gave English the inch. The abbreviation oz does not come from English at all but from the Italian onza or oncia. Over the centuries many regions and trades used different ounces: the English Tower ounce of 29.16 g was abolished by Henry VIII in 1527, and the Dutch ons was redefined as exactly 100 g in 1820.

The avoirdupois ounce used for everyday goods is one sixteenth of a pound, exactly 28.349523125 g or 437.5 grains, the standard in the US and under the UK imperial system. It is not the same as the troy ounce for precious metals, and neither is the fluid ounce, which measures volume. Ounces still describe portions such as steaks and burgers, and they show up in unexpected places: fabric is graded by weight per area, so a 16 oz denim is a heavy cloth, and the copper on a circuit board is specified in ounces, where 1 oz is roughly 34.7 micrometres thick.

1 ounce = 0.02834952313 kilograms (approximately).

Sources: Wikipedia: Ounce; NIST Guide to the SI, Appendix B.8 (mass conversions)

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