# Why did the French implement decimal time during the French Revolution? **URL:** \ **Category:** Factual Questions\ **Created:** [September 17, 2019, 5:33pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390 "2019-09-17T17:33:11Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [September 18, 2019, 5:21pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/21 "2019-09-18T17:21:00Z")
> [@Nava](#): > > Underline mine: what French system, and no we hadn’t. Many of our unit names were similar (Romance languages and neighbors, you see), but at the time there was your libra castellana, your libra leonesa, your libra aragonesa… and your vara castellana, and your vara navarra and your vara leonesa and… > > Vara means “long, thin piece of wood” but it’s also a measurement of length and the sticks used to measure according to that unit. There’s a clothesmonger in my home town which is in their 6th generation (the 7th is starting to join now), founded in 1860 IIRC. They use their metric varas (one meter from end to end) but also have on display their original varas from Aragon, Navarre and Castille. From what I’ve read it happened when the Bourbon dynasty took over the Spanish crown. An order was issued in 1718 telling the army to use French measurements: > [@](#): > > and for the measurements they will use the fathom and foot of France, as it has been referred in the Article 14, in order that being general and common in the whole Spain, they would be avoided the doubts and confusions that cause the ordinary measurements of every province A lot of local Spaniards still used the traditional measurements they were used to, but this was the official policy of the Spanish government. From 1720 to 1760, the Spanish government used the French fathom (called the toise in French and the toesa in Spanish) as its official unit when there were projects like building a road, a bridge, a fort, a port, or a civic building. In 1760, King Carlos III modified the official policy. The fathom would still be used for military buildings but the Burgosian rod (vara de Burgos) would be the official unit for civilian projects. But the problem was there was no clear standard of exactly how long a Burgosian rod was. So a value was set; a Burgosian rod was equal to 7/3 of a Parisian fathom. [The units of length in the Spanish treatises of military engineering](http://www.2iceshs.cyfronet.pl/2ICESHS_Proceedings/Chapter_16/R-8_Navarro_Merino.pdf) ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [September 18, 2019, 5:25pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/22 "2019-09-18T17:25:56Z")
> [@Exapno\_Mapcase](#): > > The big exception are sodas, which of course have grown tremendously. A Coke bottle was 6 oz. for decades. Underdog Pepsi fought back by making their standard size 12 oz. for the same nickel. Much later, when the soda industry was transitioning into plastic containers and standard sizes, Pepsi came up with a two-liter bottle that the whole industry adopted. That’s 67.6 oz. and is often on sale for 99 cents, close to the same buying power as a nickel in the early part of the 20th century, but consumers get 11 times as much. Soda prices are basically insane. Last month, I saw a twelve pack of soda selling for less than a six pack of the exact same soda being sold next to it on the shelf. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [September 18, 2019, 5:39pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/23 "2019-09-18T17:39:09Z")
> [@Limmin](#): > > In a decimal time system\*, how long is a “second?” > > I’m going to guess that part of the appeal of our current system, being based on 60s, is that one second is about the same duration as a human heartbeat, therefore easy to visualize. > > My thought: If we had a 10 hour day, each hour 100 minutes, then each minute 100 seconds, then one decimal second would be 0.864 of our current seconds. Clocks would tick faster, but hours would be a lot slower than before (about 1.5 of our current hours). If you read the (short-lived) French law, then one “decimal second” [seconde décimale] is equal to 1/100000 of a day. There were indeed decimal clocks in France, for a few years, anyway. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 18, 2019, 5:49pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/24 "2019-09-18T17:49:43Z")
> [@Limmin](#): > > My thought: If we had a 10 hour day, each hour 100 minutes, then each minute 100 seconds, then one decimal second would be 0.864 of our current seconds. Clocks would tick faster, but hours would be a lot slower than before (about 1.5 of our current hours). Actually, in such a decimal system, a New Hour would be exactly 2.4 Old Hours. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [September 18, 2019, 5:52pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/25 "2019-09-18T17:52:21Z")
> [@Little\_Nemo](#): > > From what I’ve read it happened when the Bourbon dynasty took over the Spanish crown. An order was issued in 1718 telling the army to use French measurements: > > A lot of local Spaniards still used the traditional measurements they were used to, but this was the official policy of the Spanish government. 1.- The military is not the whole government. Not only locals, but most branches of the government used the local systems of measures. 2.- The Spanish crown was still two crowns at the time (under Felipe V but also under Carlos III, both hereby mentioned under the Castilian numerals but with different numbers for Navarre); the largest crown included multiple realms with their own systems of measure. 3.- There wasn’t one French system. “The Parisian fathom” to use a unit your own cite mentions was in use in part of France. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [September 18, 2019, 7:05pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/26 "2019-09-18T19:05:07Z")
> [@Exapno\_Mapcase](#): > > And most canned goods have shrunk. Older recipes might call for a 12 oz. can of tomato sauce, but today’s shelves would only have 11.5, or 11 or even 10 oz. cans. (Just an example. Don’t quote this.) Do you try to adjust all the other ingredients? Buy two cans and let some go to waste? > > Cereal boxes have continually shrunk the same way. It’s a near universal. Actually that’s less driven by a desire to fool the consumer by stealthily shrinking packages while keeping the same price, and more driven by consumer bitching about price point changes for the larger increment of measure. In other words, people get it in their head that “a can of coffee”(to use an example) ought to cost $X dollars. But when prices rise, manufacturers find it less problematic to keep the price the same, and adjust the size, instead of keeping the size the same and adjusting the price. That way, “a can of coffee” mostly costs the same, but may be 15 oz rather than a full pound. It also gives manufacturers more wiggle room to maintain a particular price point relative to competitors while maintaining their preferred profit margins. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [September 18, 2019, 7:41pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/27 "2019-09-18T19:41:55Z")
> [@bump](#): > > Actually that’s less driven by a desire to fool the consumer by stealthily shrinking packages while keeping the same price, and more driven by consumer bitching about price point changes for the larger increment of measure. > > In other words, people get it in their head that “a can of coffee”(to use an example) ought to cost $X dollars. But when prices rise, manufacturers find it less problematic to keep the price the same, and adjust the size, instead of keeping the size the same and adjusting the price. That way, “a can of coffee” mostly costs the same, but may be 15 oz rather than a full pound. It also gives manufacturers more wiggle room to maintain a particular price point relative to competitors while maintaining their preferred profit margins. Yes, absolutely. IOW, no connection to the metric system at all. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [September 18, 2019, 8:18pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/28 "2019-09-18T20:18:54Z")
> [@Limmin](#): > > In a decimal time system\*, how long is a “second?” That’s like asking “in a decimal linear measurement system, how long is a foot?” There are a few likely built-in natural durations to chop into segments for a decimal time system. The “second” ain’t one of them. I would go with the day, myself. We would of course eventually define the day in terms of a certain number of something else defined as the microday or the attoday or some such thing, rather than obtaining the perfect measure of the average day, but in plain parlance the time from one sunrise to the next = day, then divide that up into millidays (shorter than minutes) and slice those into hundredths to get a momentary unit akin to a second (they’re about 3/4 of a second actually). I got obsessed with it as a hobby once upon a time and made conversion charts and actually memorized the exact time (as measured in conventional hours::minutes::seconds) that each deciday rolled past and so forth. ETA: my name for the 100,000 of a day was “centimil” ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [September 18, 2019, 9:00pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/29 "2019-09-18T21:00:08Z")
Let me observe that any attempt to mess with the week would run afoul every Abrahamic religion in the world. In one of his regular columns that ran in F&SF, Asimov discusses the question of what the English learned in school since they didn’t learn long division (a fact mention by, IIRC, Pepys) what arithmetic did they learn. The answers included such things as pounds, shillings, and pence, but also learning how to convert among the dairyman’s ounce (and pint and quart and gallon), the vintner’s ounce, the brewer’s ounce, and so on. So standardization was a really welcome change. Of course, the English did not adopt metric until the 1960s, but at least they adopted some standard. Note that the British ounce is not the same as the US ounce and the pint, quart, and gallon are even further off. Notice that the claim that “A pint’s a pound the world round” is and always was false everywhere. A US pint (of water at 4 deg C, 1 At pressure weighs about 4% more than a pound) and, while 16 imperial ounces of water does weigh one pound, a pint is 20 oz. and weighs 1.25 lb. The sensible way to decimalize time would be to have 10 hours of 100 minutes of 100 seconds each and the new second would indeed be .846 old seconds. A pulse that currently reads 60 would now be 69.4444… ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [September 18, 2019, 9:45pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/30 "2019-09-18T21:45:04Z")
The US gallon is the wine gallon or the Queen Anne gallon, which was required by statute in the UK from 1707 through 1826 when the adoption of the the Imperial system changed it. Obviously that was after the US revolution. The history is complex but the same is true of anything that is focused around taxation. Here is a good history to just show how complicated it was along with trying to keep sizes similar to the roman sizes while supporting division by 1/8ths for the “pieces of eight” > **[Carysfort\_Wine\_Gallon.pdf](https://www.sizes.com/library/British_law/Carysfort_Wine_Gallon.pdf)** > > 49.73 KB The difference in time is that while France was trying to develop a cohesive unified unit of measure there was already an international standard for degrees of angle and time while the same didn’t exist for volume, weight, and length. It does take a lot of work to convert from decimal if you reads some of Laplace’s work which he did use decimal degrees…which a right triangle == 100 degrees and a circle would have been 400 degrees. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [September 18, 2019, 10:37pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/31 "2019-09-18T22:37:21Z")
> [@Nava](#): > > The military is not the whole government. Not only locals, but most branches of the government used the local systems of measures. True, but I imagine that things like the court system and the diplomatic corps and the post office didn’t use measurements all that much. It was the military that built things for the government so they were probably the only branch of the government that used official measurements of a regular basis. And while I’ve acknowledged that people in Spain may have stuck with the traditional local measurements they were used to, I think it’s reasonable that when we talk of Spain doing something to refer to what the the Spanish government does. If I said “Spain joined the European Union in 1986” most people would accept that I was talking about an action by the Spanish government and I didn’t mean that all of the individual people who lived in Spain somehow joined the EU. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [September 19, 2019, 9:15am UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/32 "2019-09-19T09:15:34Z")
> [@Little\_Nemo](#): > > . The French had one system of measurements, the British had another one, The French, like the British, had _hundreds_ of different measurement systems. The British Imperial system, with _one_ system of measurements was developed over decades if not centuries, and was resisted by users of customary measures every step of the way. That I know of, they were still working on standardizing Imperial weights and measures in the late 1800s. You could, if you wanted, convert between the different systems of measurement: you could sell a bag of wheat at a different port, and than have it shipped to a different port, and then have it sold to a different customer. But if you were a farmer, you couldn’t actually compare prices at different destinations, because you didn’t know what the measures meant. And that’s just one grain: in the same location, you might be using different measures for different grains. ---
**Author:** ![APB](https://avatars.discourse-cdn.com/v4/letter/a/8e8cbc/32.png) [@APB](https://boards.straightdope.com/u/APB)\ **Post date:** [September 19, 2019, 11:39am UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/33 "2019-09-19T11:39:24Z")
> [@Tim\_T-Bonham.net](#): > > The calendar change in England caused some riots, that people laugh about now. But it was a real hit to the workers: they paid rent by the month, but that month was suddenly 10 days shorter, but the rent was unchanged. And most workers were paid by the day, so their income didn’t change, but their rent did. All that’s simply incorrect. [The 1752 calendar riots never happened](https://www.academia.edu/2342015/Give_us_our_eleven_days_) and section VI of [the 1751 Calendar Act](https://en.wikisource.org/wiki/British_Calendar_Act_of_1751) dealt with the problem of rents etc. by specifying that they should be paid as if the old calendar was still in use. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [September 20, 2019, 1:20am UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/34 "2019-09-20T01:20:26Z")
> [@Melbourne](#): > > The French, like the British, had _hundreds_ of different measurement systems. The British Imperial system, with _one_ system of measurements was developed over decades if not centuries, and was resisted by users of customary measures every step of the way. That I know of, they were still working on standardizing Imperial weights and measures in the late 1800s. > > You could, if you wanted, convert between the different systems of measurement: you could sell a bag of wheat at a different port, and than have it shipped to a different port, and then have it sold to a different customer. But if you were a farmer, you couldn’t actually compare prices at different destinations, because you didn’t know what the measures meant. And that’s just one grain: in the same location, you might be using different measures for different grains. Exactly. I remember visiting a small village in rural France that had preserved its 16th century market plaza. In the middle of it was a large slab of… well, it probably wasn’t concrete but it looked like it, sandstone presumably ? I don’t know. The top of the slab was flat, with a number of hemicircular divots of different widths and depths, which were the official measures for this or that grain. If you bought one Town Unit of barley and you thought you had been cheated, you’d ask the town official to pour the sack into the official barley divot, and if it didn’t reach the top then you’d have a case. Pointedly, next to the slab was a little pedestal which used to feature the town’s stocks. Caveat motherfucker. Merchant guilds did not fuck around with cheats, for good reason : a market with a reputation for dishonesty or lax standards would be avoided ; and reputation was EVERYTHING back in the day. And you thought a bad Yelp review was harsh :D. But, again, this was the measure for that one pissant village. The next village over presumably had its own slab with its own divots, which were implicitly much better divots that the ones those weirdoes over \*there \*use, and the bastards put the toilet paper roll the wrong way around too ! ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [September 20, 2019, 1:27am UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/35 "2019-09-20T01:27:36Z")
> [@Hari\_Seldon](#): > > Let me observe that any attempt to mess with the week would run afoul every Abrahamic religion in the world. Again, that was absolutely the point, in the case of French revolutionaries. ---
**Author:** ![Cugel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cugel/32/1199_2.png) [@Cugel](https://boards.straightdope.com/u/Cugel)\ **Post date:** [September 20, 2019, 8:04am UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/36 "2019-09-20T08:04:09Z")
> [@Banksiaman](#): > > Hubba, hubba! Check out the pomegranates on Miss Fructidor (18 Aug - 16 Sept). According to the SDMB software, you posted on 9-18… maybe Fructidor is the mysterious 18th month? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [September 20, 2019, 1:06pm UTC](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390/37 "2019-09-20T13:06:16Z")
The main thing is probably, as already mentioned, that there already was an international standard for time. Another is that we much more rarely deal with time unit conversions the way we deal with other unit conversions and it was even rarer back then. [Previous page](https://boards.straightdope.com/t/why-did-the-french-implement-decimal-time-during-the-french-revolution/840390.md?page=1)