Measuring Misfortune: The Pirate Who Stole America’s Metric System

In the late 18th century, America was THIS close to adopting the metric system. Washington wanted it. Jefferson wanted it. France was helping by sending a ship with official metric weights and measures. But the entire plot was ruined by British Pirates. In this episode, we tell the story of America’s closest flirt with the metric system, how the plan failed and then we play the quiz with Comedian Glen Tickle!

Today’s story is about pirates.

But it’s also about science, and bureaucracy, and just how close the United States came to joining the rest of the world in using meters and kilograms. This is a weird tale of swashbuckling sabotage—with the twist that it doesn’t involve sword fights or treasure maps… but instead, a very specific copper cylinder.

Before we get into that story, I have to tell you about something I find absolutely fascinating. 

If you drive parts of I-19 in Arizona or along I-394 near Minneapolis—you’ll actually find highway signs marked in kilometers instead of miles. I-19 runs from Tucson to Nogales, right on the U.S.–Mexico border. When the road was constructed in the 1970s, there was a push for metrication in the U.S., and the Federal Highway Administration allowed metric signs as part of a broader metric test program. The thinking was that metric signage would help facilitate trade with Mexico, which uses the metric system. While the metric push fizzled out nationally, the signs stayed—so to this day, you’ll see distances in kilometers along I-19. In the early 1990s, a short section of I-394 in Minneapolis used dual-unit signage (both miles and kilometers) as part of an experimental project aimed at familiarizing the public with the metric system. That effort was also part of a brief national metrication push, but like I-19, it was never expanded. Most of the metric signage has since been removed, but some remnants linger. So in short, these are leftovers from the last time the U.S. seriously flirted with going metric in the 1970s and ’80s. The signs are oddities now—but they’re relics of a road not taken.

Despite the widespread use of the imperial system in everyday American life, the metric system quietly exists in more places than you might expect. Science, medicine, and the military all rely heavily on metric units—doctors measure medication in milligrams, scientists calculate distances in meters and kilometers, and military maps use metric grids. Bottled beverages are labeled in liters, and most car manufacturers list engine displacement in liters instead of cubic inches. Even track and field events measure races in meters. Yet despite these scattered adoptions, the U.S. remains resistant to fully embracing metrication. Road signs overwhelmingly show miles. Temperatures are Fahrenheit. People measure their height in feet and inches. It’s as if the U.S. has one foot in the metric world—but refuses to take the next step.

Now we’re going all the way back to the 1790s, when America was still figuring out how much things should weigh.

In the early years of the United States, measurement was a disaster.

Different states used different units. Sometimes even towns used their own standards. There were British imperial units, leftover Dutch and Spanish measurements, and local adaptations. You might buy flour by the bushel in one place and by the stone in another. And good luck figuring out how long a “rod” was without arguing with your neighbor.

This wasn’t just annoying—it made commerce harder. You couldn’t trust the quantity you were buying or selling, and it stifled interstate trade. Even George Washington called for a standardized system of weights and measures in his very first address to Congress.

On January 8, 1790, he said in his First Annual Address to Congress, “Uniformity in the currency, weights and measures of the United States is an object of great importance, and will, I am persuaded, be duly attended to.”

So when Thomas Jefferson became Secretary of State in 1790, he decided to fix it.

Now, Jefferson was a bit of a measurement nerd. He loved scientific reasoning and Enlightenment ideals. And he believed America needed a rational, consistent, universal system—something rooted in logic, not tradition.

At the same time, across the ocean, France was having its own revolution. And in the middle of all that chaos, French scientists were busy inventing a new system of measurement based entirely on the natural world.

They called it the metric system. Well, technically they called it, “Système métrique décimal,” but you know me and French pronunciations. And this all happened while the U.S. was still dragging their feet debating a standardized system of measurement. Jefferson wrote: “The element of measure adopted by the National Assembly excludes, ipso facto, every nation on earth from a communion of measurement with them.”

This new French system was elegant. A meter was one ten-millionth of the distance from the North Pole to the Equator along the meridian. A liter was the volume of a cube 10 centimeters on each side. And a kilogram? That was the mass of one liter of water at the freezing point. Everything was base-10. Simple. Logical. Standardized. Easy to teach to children. Jefferson loved it.

In fact, he wrote extensively to French scientists, expressing interest in bringing this revolutionary system to the United States. And the French, eager to spread their rational ideas across the globe, decided to help. They commissioned the creation of a set of official metric standards—one kilogram and one meter—to be sent to the U.S. as diplomatic and scientific gifts.

And to deliver these precious prototypes, they chose a man named Joseph Dombey.

Joseph Dombey was a respected botanist and scientist. He’d traveled South America collecting plant specimens, worked with the French Academy of Sciences, and supported the revolutionary government in France. But in 1794, he was tasked with something different: bringing the metric system to America.

He set sail for Philadelphia with an official kilogram—a copper cylinder, precisely calibrated to match the new French standard. This wasn’t just a gift—it was a physical reference, something American scientists could use to create their own identical copies. It was, quite literally, the foundation of a future metric America. Jefferson was waiting. Dombey was ready.

And the United States was about to change… forever.

But then—something happened at sea.

What happened to Dombey’s ship? Why didn’t the U.S. receive the kilogram?

Stick around—because when we come back, pirates get involved. And everything goes sideways.

So, Joseph Dombey, carrying a kilogram that could’ve changed American history, set sail from France to the United States. But he never made it.

His ship was intercepted.

Now, this wasn’t the work of random criminals—it was British privateers.

At the time, France and Britain were basically in a constant state of war, and privateering was a common practice. Governments issued “letters of marque” to private citizens, giving them legal permission to raid enemy ships. So these guys were pirates, but with paperwork.

Dombey’s ship was captured somewhere in the Atlantic. Possibly near the Caribbean. He was taken prisoner and brought to the island of Monserrat, which was a British held island in the Caribbean, and he died in captivity—never completing his mission. And so at that time – in 1794 – the metal kilogram weight never made it to the U.S. and was lost.

And that single event derailed the U.S.’s early flirtation with the metric system.

Back in Philadelphia, Jefferson never received the kilogram. The French revolution was making communication chaotic. And without a standardized reference in hand, the metric system remained just an idea.

Jefferson couldn’t convince Congress to act without that physical object. And as administrations changed, so did priorities. The opportunity faded.

America stuck with the British imperial system, even after Britain itself began transitioning to metric in the 20th century.

Congress eventually legalized metric units in 1866, but adoption was never mandated. Today, the U.S. is one of only three countries in the world that hasn’t fully embraced the metric system. The others? Liberia and Myanmar.

All because one man’s voyage was cut short by pirates.

Here’s a fun twist: that very same kilogram? It turned up later. It’s exact path isn’t certain, it was probably confiscated by the British – that’s what happened to most of the stuff seized by these privateers back then. 

Somehow it ended up finding its way to America around a century later. It was eventually transferred to the National Bureau of Standards, which is now the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. NIST currently holds the artifact and confirms it as one of the earliest metric standards intended for the U.S.

But by the time it made it to the U.S., the imperial system had become deeply entrenched. Too many industries, too much infrastructure, and too many habits had formed around inches, feet, gallons, and pounds.

That single missed connection in 1794—caused by a pirate raid—may have been our best chance to make the switch.

So, what if Dombey had made it? What if Jefferson received the kilogram? Would we all be measuring our height in centimeters today? Would American ovens be set to 180 degrees Celsius? Would your speedometer have kilometers per hour on the outside ring instead of buried inside?

It’s hard to say for certain—but historians agree that early adoption would’ve given metric a much better shot in the U.S. The country was still young. Flexible. Open to new systems. If it had been standardized from the start, Americans today might not even think about metric being foreign.

Instead, we have generations of students wondering why water freezes at 32 degrees, not zero.

All because one copper cylinder didn’t make it to its destination. The Internet Says it’s True.

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