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How Pirates Of The Caribbean Hijacked America's Metric System (npr.org)
If the United States were more like the rest of the world, a McDonald's Quarter Pounder might be known as the McDonald's 113-Grammer, John Henry's 9-pound hammer would be 4.08 kilograms, and any 800-pound gorillas in the room would likely weigh 362 kilos. NPR explores: One reason this country never adopted the metric system might be pirates. Here's what happened: In 1793, the brand new United States of America needed a standard measuring system because the states were using a hodgepodge of systems. "For example, in New York, they were using Dutch systems, and in New England, they were using English systems," says Keith Martin, of the research library at the National Institute of Standards and Technology. This made interstate commerce difficult. The secretary of state at the time was Thomas Jefferson. Jefferson knew about a new French system and thought it was just what America needed. He wrote to his pals in France, and the French sent a scientist named Joseph Dombey off to Jefferson carrying a small copper cylinder with a little handle on top. It was about 3 inches tall and about the same wide. This object was intended to be a standard for weighing things, part of a weights and measure system being developed in France, now known as the metric system. The object's weight was 1 kilogram. Crossing the Atlantic, Dombey ran into a giant storm. "It blew his ship quite far south into the Caribbean Sea," says Martin. And you know who was lurking in Caribbean waters in the late 1700s? Pirates.
In your field the centimetre might be dead but it's not a dead unit in the SI system. It's used all of the time in Canada. It's a perfect unit because people can visualize what 1 cm is. It's harder to visualize 10 mm or 0.01 m. And for people that are used to inches it's the closest unit.
And if the centimetre is dead then the centilitre would be dead for the same reasoning. While not in use in Canada (we use the millilitre) the centilitre is sometimes used for small volumes in Europe. I recently bought some bottles to store home made vinegar and they were made in Italy. The sticker said the volume was 50 cl, not 500 ml. You can see it used on some cans of pop.
It's 12 pence in a shilling, 20 shillings in a pound.
The reason a foot is divided into 12 inches is because it lets you divide a foot evenly in half, thirds, quarters, sixths, or twelfths (eights are also possible with only a half inch). So dividing a foot into 12 inches lets you hit 3 of the most common subdivisions (half, third, quarter), and 4 of the 5 smallest subdivisions (sixth, missing fifth) using only integers.
Dividing units into 10 only gives you 1 of the 3 most common subdivisions (half), and only 2 of the 5 smallest subdivisions (half, fifth) using only integers.
English unit subdivions weren't picked at random. They were selected because they're more practical. A foot is 12 inches for easy subdivision. The English units of volume are based on halving (easy to do if you don't have standardized containers but you do have a scale) - a gallon is 2 quarts, a quart is 2 pints, a pint is 2 cups. An acre is about how much land a peasant could work in a day, and the furlong is defined based on an acre (1 furlong x 1 furlong = 10 acres). Likewise, a mile has 5280 feet because that's 8 furlongs. You'll also note the mile subdivides as integer feet into 10 of the smallest 12 subdivisions (only a 7th and 9th of a mile is not integer feet).
Until standardized measuring instruments became cheap and commonplace, English units were simply superior. Metric is only superior today because the biggest difficulty in modern usage is doing the math by hand (or in your head), not obtaining tools to measure things accurately. Even on computers, if you're doing sequential calculations without using infinite precision, English units are superior to metric - they accrue less roundoff error. Computers store numbers in base 2, and many English unit conversions will resolve down to at least base 4 before hitting a fraction and thus losing precision in binary representation. Except for a half, metric unit conversions don't fit at all into base 2, so lose precision with almost every calculation.
We're over 200 comments in, and still no mention of The Church of the Flying Spaghetti Monster's revelation that the cause of global warming is the decline in the number of pirates.
And there we have it my friends. Not only did pirates cause the adoption of the imperial system in the USA, but the metric system causes global warming! Think of the children!!!eleven
[Poe's Law disclaimer: yes, I'm kidding.]
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