The Mètre des Archives, 1799
The Mètre des Archives, a bar of solid platinum, forged and officially adopted by the Convention in Paris in 1799.
Transcript
“How far did you say it was again? A couple of blocks, more or less?” Picture us, wandering the streets of Paris, looking for a stone shelf set into a wall, across from the Luxembourg Gardens, 36 rue Vaugirard to be exact, on a warm summer’s afternoon several years ago. I’d read about it and it seemed like one of those quirky things one does on vacation when you can’t stand Yet Another Cathedral. So my dutiful husband follows me around – love may not always be blind, though it is patient – and eventually we find it, and thus the picture of me standing next to the last remaining original mètre étalon, a standard meter installed in 1796 to enable citizens to calibrate their own measuring devices.
Now after a couple of centuries of wear and tear, that meter is pretty rough now, and while it sufficed, it was never terribly precise, and certainly not as precise as the standard meter that came after that, or the one after that, or the one after that, or the one after that. This is a not-terribly-long story about a not-terribly-short stick that took about a century to have implications far and wide, once almost everybody agreed on it.
A document that changed the world: The Mètre des Archives, a bar of solid platinum, forged and officially adopted by the Convention in Paris, 1799
I’m Joe Janes of the University of Washington Information School, and if you’re the sort of person who thinks that “I love you, a bushel and a peck” is insufficiently specific, you’ve come to the right place. Bushels and pecks are but 2 of the hundreds and thousands of units of measurement invented since time immemorial. Linear and area measurements likely came first; one book on metrology lists 63 historical examples in its index, acres, cords, fathoms, furlongs, rods, thumbs, yards, 8 different kinds of cubit, a whole bunch you’ve never heard of, and of course feet, which are obvious because, well, most of us have them and there they are, and much the same could be said for lots of early measurements based on the proportions of the human body. But – which body, or more to the point, whose? Egyptian “standard” cubits, used for reference in building, were based on the length of the pharaoh’s arm from elbow to tip of middle finger, plus the span of his hand; the yard derived from the length of King Henry I’s arm; his great-grandson Henry III established the weight of a penny to be 32 grains of wheat, taken from the middle of the ear, and an ounce to be 20 pennies, and 12 ounces make the London pound. Got it? Many of these standards were established by edict or decree and some were “published” in a sense: We have Egyptian royal cubits made of wood, and a Roman foot made of bronze, there was a set of metal weights established by Charlemagne. Some emerged from everyday, often local, practice; areas were often measured in terms of how much land could be plowed and by a man with an ox in a given day, and thus might be different in size for different crops and in different places.
As you might have guessed, our story takes us back to France, in this case Revolutionary France which was, um, revolutionary – and not exclusively in political terms, but we’ll get there shortly. July 14 of 1789 the Bastille falls; 3 weeks later, on the 4th of August, the new National Assembly abolishes the feudal system, which meant that the collection of over 700 units of measurement often used for fraud and abuse effectively went with it, so yay for liberty but what do we do now? No less a figure than Talleyrand, the notorious side-switcher, then a bishop who had supported the appropriation of church property, eventually to lead the French delegation to the Congress of Vienna, was asked to propose a complete overhaul, meant to unite the world in sweeping away all traditional measures, based first on the period of the swing of a pendulum.
That didn’t fly, but the Assembly did eventually settle on a decimal system – very much in vogue as they also implemented a new calendar with new months, weeks of 10 days of 10 hours of 100 minutes of 100 seconds, for real – defining a “meter” (from the Greek for “measure”) as 1/10,000,000th of the meridian distance through Paris from the North Pole to the Equator, perhaps because that was roughly half the size of the existing medieval toise, the span of a man’s 2 arms. A standard iron toise was embedded in the wall of the Grand Chatelet by the 14th century and the refined Toise of Peru – really – was made official in 1766.
Louis XVI, still alive and sort of reigning, though in prison, approves this plan in June of 1791, his last free official act, the day before his ill-fated attempt to flee the country with Marie-Antoinette. Many twists and turns follow, first among which is how in the heck do you determine that meridional distance? Answer: send out 2 surveyors in 1792 with a complex plan to measure from Dunkirk to Barcelona, starting in Paris and headed in opposite directions. Which was a breeze, except for the imprisonments, the technical problems, the mountains, the political upheaval, the accidents and near-fatal injuries, the battlefronts, and the fact that one of them made meticulous and scrupulous notes and measurements and the other one didn’t, which meant that errors were baked into his numbers from the word go and he knew it but didn’t know how or why and didn’t want to admit it until his wife came along to help sort it out, kind of. Oops.
1793, the Terror grips Paris; Louis is executed in January, many scientists and thinkers follow for being insufficiently “revolutionary”. Bread riots break out in April of 1795 and within the week, the Convention formally adopts and mandates the metric system in the law of 18 Germinal, year III, with a motto no less: “For all times. For all peoples.” Very noble – though they acted not so much out of a sense of rationality, order and universality as desperately trying to control hyperinflation and save their own skins. Which didn’t work – they were overrun by new food riots within the month, but the deed was done. Bear in mind – the survey was still going on, and would continue for another 3 years, so they made a guess with a provisional version which got plonked on the wall we found.
Many more complications later, they finally defined something official based on the survey (which used 2-toise measuring sticks, by the way), in the form of a bar of pure platinum, which was forged by a formal royal goldsmith coaxed back from hiding to be the standard and placed in the National Archives – hence the name – in 1799, mimicking that familiar centuries-old physical toise standard. It’s 25mm wide and 4 mm deep and is – or was - exactly 1 meter in length, by definition, meaning that, that particular thing, was “the meter” and everything else needed to be gauged to that object, not because it meant or represented anything inherently, but because it was made for that purpose; it’s the idea of the thing and the actuality of the thing itself that establishes what the “standard” is.
It’s not, any more, partially because physical objects change no matter how carefully they’re kept, and finally fixing the errors in the original calculations required adding .2mm to the definition, approved in 1872 by the International Metre Commission, in Paris of course, and further meetings of almost entirely Western national representatives led to the Treaty of the Metre in 1875 (Paris again) and the establishment of the International Bureau of Weights and Measures, guardians of the system to this very day. New prototypes were fabricated in 1889; the US got number 27 in a lottery, and that was the official American standard until 1960, now sitting in a museum at the National Institute of Standards and Technology in Maryland.
All fixed, yes? No. “The people” did not embrace this wonder of rationality for the reasons people don’t like change – these newfangled things are unfamiliar, we don’t understand it, why are we doing this, and it takes work, many other processes and functions have to change too. They didn’t like the new measures or the new names. So the meter gets new-old names to make adoption easier in 1800, which failed, even Napoleon gave up on them in 1809, permitting the use of older and more familiar measures; Louis XVIII bans the metric units outright in 1816, Louis-Phillippe reverses that in 1837 and in 1840, finally, finally, the meter is the meter, whatever it is. Except – it isn’t; it’s since been re-re-defined, in terms of the wavelength of krypton-86, and now, now – at time of recording - 1/299,792,458th of the distance traveled by light in a vacuum. A clumsy, decidedly unlovable definition, still for all times, for all people as the motto remains, even though removed from all human experience or reference.
Now, they tell us, it’s all settled, one nice tidy package, the Système international, integrated, seamless, you’re welcome, the metre and its cousins the second, the kilogram, the ampere, the kelvin, and mole and candela, and so many of our processes, devices, and lives are bound up by increasingly precise measurement that it’s hard to imagine any dramatic revolutionary – heh – overhaul, and yet the drive for precision goes on, no matter how minuscule or seemingly meaningless the refinement may seen.
The meter as we have it is the result of untold mistakes, errors, political intrusions and intrigues, and misadventures, which matter, but really don’t because no matter how you get there, there you are – the meter is the meter because everybody says, so and more or less agrees and it looks more or less like half of a centuries-old French rod and that is that.
Creating and articulating a standard, of anything, is relatively easy; communicating it is harder, and getting people to agree, and use it, and give up the old ways, is harder still, which is Americans have 2 liter soda bottles and grams of sodium on nutritional labels and used to have 35mm photographic film and that’s about it, although, even our old ones have succumbed; the yard for instance is now officially 0.9144m. So it goes.
The metric system was meant to be divorced from any particular culture and based solely on rationality and Nature, capital N. But you can’t remove the meter, or any measure, from its social and historical context, and the only way for a measure to be universal is if you do or at least pretend to. The meter is what it is because it emerged from Revolutionary France; if some other system had been invented, adopted, promulgated somewhere, somewhen else – it’d be different, but the net effect would be effectively nothing, because the standard is the standard…more or less.
References
Alder, Ken. The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World. New York: Free Press, 2002.
—ĔĔ. The Measure of the World. Dibner Library Lecture. Washington, D.C: Smithsonian Institution Libraries, 2003.
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“History of the Metre.” In Wikipedia, May 15, 2024. .
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McDonald, Daniel McLean. The Origins of Metrology: Collected Papers of Dr. Daniel McLean McDonald. Cambridge: McDonald Institute for Archaeological Research, 1992.
—ĔĔ. The Origins of Metrology: Collected Papers of Dr. Daniel McLean McDonald. Cambridge: McDonald Institute for Archaeological Research, 1992.
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Williams, Jeffrey H. Defining and Measuring Nature: The Make of All Things. IOP Concise Physics. San Rafael, CA: Morgan & Claypool Publishers, 2014.
Winchester, Simon. “Galileo, Krypton, and How the True and Accurate Meter Came to Be.” Wired. Accessed July 4, 2024. .
World in the Balance : The Historic Quest for an Absolute System of Measurement - University of Washington. Accessed July 4, 2024. .