Apothecaries' weight

Apothecaries' weight is a historical system of mass units that were used by the apothecaries and physicians in the past for the purpose of prescribing and compounding medicines. This system is distinct from the more commonly known avoirdupois system, which is used in the United States for weighing general goods and produce. The apothecaries' weight system was officially used in many countries until the 19th and early 20th centuries, when it was gradually replaced by the metric system.

History

The origins of the apothecaries' weight system can be traced back to the ancient Roman and Greek civilizations. It was standardized in the Middle Ages and used extensively across Europe. This system was brought to the United States by early settlers and remained in use until the adoption of the metric system.

Units

The basic units of the apothecaries' weight system include the grain, dram (or drachm), ounce, and pound. The system is based on a pound of 12 ounces, an ounce of 8 drams, and a dram of 3 scruples. The smallest unit, the grain, is the same in both the apothecaries' and avoirdupois systems, and is derived from the weight of a single grain of wheat.

• Grain: The smallest unit of weight in the apothecaries' system, used to measure very small quantities.
• Dram (Drachm): Equal to 3 scruples or 60 grains.
• Ounce: Equal to 8 drams or 480 grains.
• Pound: The largest unit in the apothecaries' weight system, equal to 12 ounces or 5760 grains.

Conversion to Metric

With the widespread adoption of the metric system, the use of apothecaries' weight has declined. However, its influence can still be seen in certain areas, such as the use of grains to measure the mass of bullets and precious metals. Conversion to metric units requires knowledge of the specific unit being converted. For example, one grain is equal to approximately 0.0648 grams.

Modern Usage

Today, the apothecaries' system is largely obsolete, with the metric system being the standard for medical prescriptions and measurements worldwide. However, understanding the apothecaries' weight system is important for historical research and for interpreting old medical documents and prescriptions.

See Also

• Metric system
• Avoirdupois system
• History of pharmacy