The proposal, conceived by a bunch of pointy-headed Parisian philosophers, sounded brilliant: A universal system of measurement, derived from decimal-based units and identified by a shared set of prefixes.
It would end the era of merchants buying goods according to one unit, selling in another, and pocketing the ill-gotten profit. It would simplify scientific calculations and enable the free exchange of ideas around the world.
It was an enlightened system for an enlightened time. If only the French scientists could persuade other countries to adopt it.
But pirates have a way of ruining even the best-laid plans.
In 1793, botanist and aristocrat Joseph Dombey set sail from Paris with two standards for the new "metric system": a rod that measured exactly a metre, and a copper cylinder called a "grave" that weighed precisely one kilogram.
He was journeying all the way across the Atlantic to meet Secretary of State Thomas Jefferson - a fellow fan of base-ten systems who, Dombey hoped, would help persuade Congress to go metric.
Then a storm rolled in, knocking Dombey's ship off course. The unlucky academic was washed into the Caribbean - and straight into the clutches of British pirates.
Technically, they were "privateers" because they were tacitly sanctioned by His Majesty's government so long as they only raided foreign ships. But it amounted to the same thing.
The brigands took Dombey hostage and looted his equipment. The luckless scientist died in prison shortly after his capture; his belongings were auctioned off to the highest bidders.
France sent a second emissary to promote the metric system. But by the time the replacement arrived, America had a new secretary of state, Edmund Randolph, who apparently didn't care much for measurement.
As the rest of the world adopted the metric system, the US continued to bumble around with unwieldy imperial units. Aaaarrrgh!
We bring you this story not just because it was just International Talk Like a Pirate Day (avast!) and an excuse to spin a swashbuckling yarn, but because, more than two centuries later, Americans are still suffering its consequences.
Had Dombey made it to the US on schedule, he and Jefferson may have talked Congress into caring about how we measure distance and mass.
This country could have gone metric right from the beginning, instead of being dragged into the system kicking and screaming. Just think of all the time we might have saved! I mean, those hours lost converting the gram measurements in Great British Bake-Off recipes alone.
Elizabeth Gentry, metric coordinator for the National Institute of Standards and Technology, cautioned that this is not quite a case of "for the want of a kilogram, the kingdom was lost."
She'd know better than anyone. Gentry's job for the past 12 years has been to talk Americans into adopting the metric system - now known as Système International, or SI.
SI is simpler and easier to use, she said, not to mention the system of choice for pretty much the rest of the world.
Gentry doesn't just talk the talk: Her car speedometer displays kilometres per hour and the weather app on her cellphone gives the temperature in degrees Celsius.
"Practicing and thinking about it and shifting the way you think - it's really pretty easy," she said.
She and her colleagues have made a convincing case: Metric units are now more commonplace than you realise.
American companies use metres and grams for most manufacturing and all international trade; we buy soda in litres, not gallons; high school chemistry students make calculations in metric every day.
"I would describe Dombey's misfortune as a missed opportunity," Gentry said.
See, in the days just after the Revolutionary War, this country had no standard system of measurement.
We barely had a single currency. A bushel of oats purchased in New Jersey contained 32 pounds of grain; but a merchant could then take his wares north to Connecticut, where a bushel was just 28 pounds, and turn a tidy profit. It was madness.
Even George Washington thought so. The president devoted part of the first-ever State of the Union to arguing for a system of standard weights and measures, which he called "an object of great importance."
Jefferson was assigned to develop a standardised system, a task he took up with gusto, but Congress only considered his proposals in a "desultory way," according to a 1973 history published by NIST.
Back in Paris, proponents of the new metric system saw their opportunity. Jefferson was a noted Francophile, and France had just helped America win the Revolutionary War.
A shared system of measurement would promote trade between the two nations and serve as slap in the face to the British, who were still fumbling about with feet and furlongs.
So they sent Dombey to Washington. He seemed like a good choice: smart, hard-working, a veteran of previous trans-Atlantic voyages.
"He was only missing one trait," joked NIST research librarian Keith Martin. "Luck."
In the previous decade, Dombey had the yield of one collecting trip stolen by the British and thousands of specimens from another expedition confiscated by Spain.
He had escaped from a Spanish prison and fled home to France only to find his country in the throes of revolution and several of his aristocrat friends in line for the guillotine. Capture by pirates was perhaps par for the course.
"The Dombey event is probably a bit of a footnote to history," acknowledged Martin. But, had he and Jefferson achieved what they set out to do, "it could have made a big difference."
Since everyone was using different systems anyway, they might have been more willing to convert to metric, Martin suggested.
At any rate, it would have given Luddites 85 extra years to adjust to the new system.
In 1875, the US signed the Treaty of the Metre, which set up the International Bureau for Weights and Measures and established metric as the system of international commerce.
But it wasn't until 1975 that Congress passed the Metric Conversion Act, which called for increased use of the metric system at home.
Gentry calls measurement "that invisible infrastructure that goes on around us every day."
Nearly every experience you have had since the moment you woke up this morning - the tick of your alarm clock, the weather forecast on TV, the cereal you poured into your bowl - was based on a measurement, probably one taken in metric units.
Dombey's dull metre rod and copper grave are a lot more important than they look.
And whatever became of those standards? After being sold, the metre and grave made their way through a series of French intermediaries to Randolph, who apparently failed to realise their significance.
No one is certain what happened next, but a similar grave ended up in the hands of land surveyor Andrew Ellicott, who was working on the street plan for Washington, D.C. A century and a half later, Ellicott's descendant A.E. Douglass found the copper cylinder in an old trunk and offered it to NIST for display.
It's impossible to tell whether this is the same grave that was stolen by pirates two centuries ago. But only six of these objects were ever produced, so Martin thinks it's likely.
Either way, the object now sits in the museum at the NIST campus in Gaithersburg, Maryland, finally surrounded by people who appreciate its worth.
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This article was originally published by The Washington Post.