weights and measures

The United States is the only industrialized country that has not yet completely converted to the Metric System. The British system (no longer in legal use in the UK, its colonies or the Commonwealth) is particularly confusing. It is impossible to summarize, but Wikipedia explains the history of UK measurement in detail.

Prior to 1826 the English system was very complex:

English units evolved as a combination of the Anglo-Saxon and Roman systems of units. Contrary to popular belief, the Norman conquest of England in 1066 had little effect on British weights and measures other than to introduce one new unit: the bushel. The two main sets of English units were the Winchester Units, in effect from 1495–1587, as reaffirmed by King Henry VII, and the Exchequer Standards, in effect from 1588–1825, as first defined by Queen Elizabeth I.

Beginning in 1826 the system was simplified, but only a bit, and was known as the imperial system:

There is a more general article in Wikipedia on “History of Measurement“.

Here are some passages that I found interesting:

The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction, and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. […]

Early Babylonian and Egyptian records and the Hebrew Bible indicate that length was first measured with the forearm, hand, or finger and that time was measured by the periods of the sun, moon, and other heavenly bodies. […]

… [T]he Greeks and Romans inherited the foot from the Egyptians. The Roman foot (~296 mm) was divided into both 12 unciae (inches) (~24.7 mm) and 16 digits (~18.5 mm). The Romans also introduced the mille passus (1000 paces) or double steps …. The Roman mile of 5000 feet (1480 m) was introduced into England during the occupation. Queen Elizabeth I (reigned from 1558 to 1603) changed, by statute, the mile to 5280 feet (~1609 m) ….

The introduction of the yard (0.9144 m) as a unit of length came later, but its origin is not definitely known. […]
Goods of commerce were originally traded by number or volume. When weighing of goods began, units of mass based on a volume of grain or water were developed. ….

The stone, quarter, hundredweight, and ton were larger units of mass used in Britain. Today only the stone continues in customary use for measuring personal body weight. The present stone is 14 pounds (~6.35 kg), but an earlier unit appears to have been 16 pounds (~7.25 kg). The other units were multiples of 2, 8, and 160 times the stone, or 28, 112, and 2240 pounds …. The ton of 2240 pounds is called the “long ton”. The “short ton” is equal to 2000 pounds (~907 kg). A tonne (t) is equal to 1000 kg.

[…] … Simon Stevin … in 1585 first advocated the use of decimal numbers for everyday purposes in his booklet De Thiende (old Dutch for ‘the tenth’). […]

In 1790, Thomas Jefferson submitted a report to the United States Congress in which he proposed the adoption of a decimal system of coinage and of weights and measures. […]

The metric system was first described in 1668 and officially adopted by France in 1799. Over nineteenth and twentieth centuries, it became the dominant system worldwide, although several countries, including the United States and China, continue to use their customary units. Among the numerous customary systems, many have been adapted to become an integer multiple of a related metric unit: The Scandinavian mile is now defined as 10 km, the Chinese jin is now defined as 0.5 kg, and the Dutch ons is now defined as 100 g. The American [US] system is unusual in that its units have not been adapted in such a manner.


Now for a question that bothers me: why does measurement of eggs vary from country to country? In Latin America they are sold by weight (kilograms). In Europe (at least in the countries that I know), they are sold in packs of ten. In North America (the US and Canada), they are sold by the dozen or half-dozen. In the Wikipedia articles on measurement, measurement of eggs is not mentioned. I will search for information on the use of dozen as a measure (for eggs and some bakery goods as well), and report any findings. We have 10 fingers (or toes), so from where did the unit of twelve come?

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