The Atlantic, on why we didn’t go metric in the late 1800s:
…the most sophisticated and powerful opponents of the metric system were anything but cranks. They were engineers who built the industrial infrastructure of the United States. And their concerns, while self-interested, were not entirely off base. Whatever the drawbacks of the English units, the inch was divided in ways that made sense to the mechanics and machinists of the era: it was built around “2s” rather than “10s,” with each inch subdivided in half and in half again—and so forth. This permitted various sizes of screw thread to have some logical correspondence to all the other increments. The same was true of the sizes of other small parts that were essential modern machinery.
This comes up again and again: metric is arbitrary. True, all measuring systems are arbitrary, but metric is arbitrary in base ten, which is a real pain in the ass when it comes to dividing things up evenly. There’s a reason why merchants and engineers might like standard measurements where you can evenly divide stuff by two and three.
Via @jimgeraghty, who is perhaps rather smug about being called out by the Atlantic on this matter. Certainly I would be.
the meter’s base is in a measurable wavelength of mumble-mumble-something. the inch is based on because we say so.
Im not saying switch, im just saying.
IIRC, the original definition of the meter was one ten millionth of the distance from the North (or South) Pole to the equator.
But the geniuses (Genii?) in France screwed up the measurement calculation and now the meter is based on a gold bar in Paris because SCIENCE!
Be fair. It would be a hard thing to do, putting together a unified system of measures while creating another calendar, another god (Reason), fighting off foreign armies, whilst trying to keep up the lists of whose heads needed severing next week!
Got to expect someone to drop the ball somewhere.
You’re making us look bad. The meter was based on a platinum-iridium alloy bar in Paris until 1960, which was 9 years before America landed on the moon (using the metric system because they weren’t particularly concerned with matching existing tooling or top-of the head calculations.)
From 1960 to 1983, like when it was used for the moon landing, the meter was based on 1,650,763.73 wavelengths of light from the 2p10 and 5d5 transition in krypton-86, like xander-drax said.
Now it’s based on how far light travels in a vaccuum in 1/299,792,458 of a second.
Twelve inches per foot is pretty darned convenient when you need to divide it into halves, thirds, quarters, or sixths. Sixty minutes per hour lets you divide evenly by five as well. 360 degrees per circle has eight, nine, ten, twelve, and twenty as divisors, too, and beats the snot out of radians and grads for most practical calculations.
Twelve inches in a foot is super convenient sometimes, and if we had a totally base-12 numbering system it would be just perfect with a base-12 version of version of metric to go with it. Easy to count on your finger joints in base-12, and two hands gives you two digits so you can count by dozens to a gross really easily. However if you’re going to count in base 10, no non-metric system out there really makes sense unless you’re dealing with something that is inherently kind of limited, like degrees in a circle. (Not often a need to convert, say, 10.6 rotations into degrees.)
Feet are nicely divisible, but when you need a third of an inch I’d much prefer something decimal.