The first systems of measurement originated in ancient Egypt. These systems, which originated over 4,000 years ago, were based upon several methods, including astronomical and meridian measurements. An Egyptian cubit was a length of 24 fingers, or roughly 450 mm. Weight was measured by a unit known as a deben, which was 91 grams of precious metal. The measurement standards of the Roman Empire were based on the Greek system, with some Egyptian concepts mixed in. Dry measurement was based on the peck, a weight of roughly 8.66 liters.

In medieval times, old standards were lost, but their names were kept and European nations adopted new standards. Troy weight originated in the 9th century in France. Traders gathered in large groups, where coins were sold by weight. The standard weight of the fair at Troyes became the standard weight for all of Europe. Troy weight was eventually adopted in the 17th Century.

In 1266, a penny sterling was considered the equivalent of 32 wheat grains. 20 pennyweights made an ounce; 12 ounces made a pound; eight pounds made a gallon of wine, and eight gallons constituted a bushel. Almost a century later, the 16 ounce pound was introduced, better known as the avoirdupois pound. Oddly enough, in England compounding scales use the apothecary standard, while the buying and selling of medicine is based on the avoirdupois standard.

The modern period started in the 16th century. European countries worked towards establishing better standards that would be more widely adopted. The metric system was developed in France. It posited that a single standard unit should be established. This unit was called the meter. All units of length and capacity were to be derived from the meter, while units of mass would be derived from the kilogram. This system is now in use around the world…

…except in the United States of America. Not long after the Constituition was signed, the systems of measurement at use in Europe were considered for the American standard. However, nothing came of this until the early 19th Century, when the British standards were adopted, except for the gallon, which was completely different from a British gallon. Avoirdupois weight is generally used in America, including the commerce of drugs. The metric system was legalized, but not made compulsory for use, which ultimately meant it was not used except in science. A feeble attempt to bring America over to the metric system was made in the 1970s, but it ultimately bore no fruit. The history of pharmacy scales and analytical balances will no doubt undergo many more changes as time goes on.