Why did the French implement decimal time during the French Revolution?

Sounds like an odd and impractical decision. Any historians or people otherwise knowledgeable on the subject who can explain that shortlived change? Thank you.

What is the impracticality to which you refer? What’s odd about decimal time, especially in the context of also implementing decimal distance, volume, area, and mass measurements?

Same reason they put forth the metric system. It was scientific and logical, rather than a hodge-podge of ancient measures. Why should a day be 24 hours of 60 minutes of 60 seconds, repeated from 1 to 12 twice a day? A decimal system represented the future, a clean slate from the creaking leftovers of the past. Why not make time part of a fully scientific comprehensive system of measurement?

Because they could?
As others have observed, there isn’t really anything “natural” about our current system, except that it’s easily divisible by a lot of numbers. Decimal time would be as easy to use, with simpler conversions. In fact, people using digital clocks tend to automatically assume decimal time, and I’ve heard stories about people being surprised that 10:59 is followed by 11:00. People end up late to affairs that way.

When I first saw Fritz Lang’s film Metropolis I noted that the clock the workers used only went up to 10, and assumed that Lang assumed a future with decimal time (and with ritzy art-deco numbers, so the “4” looks like a “+”):

But then I noticed that Frederson, the Master of Metropolis, wears a wristwatch with the conventional 12 hours, and so it seems that the worker’s clock actually represents their 10-hour work day.

The rest of the decimal system was logical. A “foot” was originally the king’s foot, since feet are variable and they had to pick one as the standard. Comes the revolution, they want to obliterate any hint of “king” so redefine distance. While they were at it, redefine everything else too that evolved willy-nilly over the centuries. If you’ve seen the mish-mash of Imperial units - feet, inches, rods, chains, cable, furlongs, miles, leagues, and nautical miles, fathoms, acres etc.and then pint, quart, gallon, hogshead, barrel, cup, and pound, ounce, stone, ton, troy ounce, troy pound, …

Humans have this instinctive desire to fix things. Once you start with things defined in feet, you slowly find you have to replace everything.

A better question for historians is, why didn’t it stick? Paragraph 22 of the “Décret relatif aux poids et aux mesures” of 18 Germinal, Year III simply states that the previous year’s law making official use of decimal time obligatory is “suspended indefinitely”.

I think the traditional time system was stronger than the traditional measuring system.

Many people don’t realize that there wasn’t an international system of measurement in the 18th century. The French had one system of measurements, the British had another one, the Dutch had a different one, the Swedes also had one, and there were several systems in Germany and Italy.

There had been a long standing movement to create a single universal system of measurements. There had been some progress; most countries had adopted a single national system, Spain had adopted the French system, and Russia had adopted the English system. So when the French revolutionaries enacted a new system, they were part of an existing movement.

The reason their system ended up supplanting the other options was mostly due to Napoleon. He didn’t actually impose the metric system on Europe; he had a different system which was a mixture of renamed metric units and traditional French units. But he did generally succeed in imposing a single system of measurements across most of the continent. The benefits of that were obvious enough that it lasted even after Napoleon fell from power. And when people decided they wanted a single international system, the metric system was the one that was chosen.

To get back to the question, there was no equivalent perceived need with time. Most places had adopted the twenty-four hour, the seven day week, and the twelve month year and it was a de facto international system. So there was no void for the proposed decimal time system to fill.

The calendar reform was really despised. 10 day weeks which was eliminated even before the repeal of the calendar. New month names. New year starting the wrong time of year. Confusion over leap days. Etc.

Wikipedia link. (Has art representing months via female personification, so spoiler boxed, because, you know, French art.)

The incredible influence of the Catholic Church was a major concern of the Republic. The old calendar was heavily oriented towards holy days, feasts, saints, etc. So out that went.

But time and the calendar are somewhat related so that was in for reform as well.

And since times were dictated by the Church for prayers and such, this was supposed to help free people from those rules, too.

Note that for centuries people were used to coins, weights and measures being dictated from above. If the King says there’s eight Ningis to one Pu, that’s the law. But time has a more traditional aspect to it.

Both the calendar ‘reform’ and the time one failed largely because they were out of step with everybody else around. The other Metric measures (distance, volume, weight) were competing with lots of different systems in different countries (and made more sense than most of them). Also, it was designed internationally, so changing to it was less political than adopting the system of a neighboring, rival country.

Interesting that these changes to measurement systems seem to always stick it to poor people.

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.

The French Republic change from a 7-day week (6 workdays and 1-day weekend off) became a 10-day week, with 9 workdays and still only 1 day off. More workdays and less time off for the workers.

And it continues today. USA corporations are using their conversion to metric measurements to sneakily reduce sizes or increase prices. Liquor used to be sold in fifths (1/5th gallon) = 757 milliliters. Now it often comes in 750 ml size (7 ml short) or even European size 700 ml (57 ml short) – but for the same price.

Even worse, the French actually had hundreds of differing systems of measurements, as there was no national standard, and each region, or even town, had their own definitions (for example, the *lieue *(league) could vary from 3.268 km in Beauce to 5.849 km in Provence). This had been identified as significant problem for trade well before the Revolution.

Hubba, hubba! Check out the pomegranates on Miss Fructidor (18 Aug - 16 Sept).
And that’s my thousandth post, every one a pearler!

This has little or nothing to do with the metric system. The same thing has happened to hundreds of products marked in ounces.

The liquor industry converted to metric for the same reason the French did: rationalizing their products. There had been 38 sizes and shapes and now there are six.

Look at ice cream as a common example. They didn’t switch the standard package size to metric units. They just shrank it from a half gallon (sixty four ounces) to one and a half quarts (forty-eight ounces).

Look at your own first link. The interpretation of those particular people is that the workers use decimal time and the masters use the old measures. This makes sense both as a class marker and because it means the workers are working half-days; if they were working ten “normal” hours, the shifts would keep shifting forward.

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.

I don’t think the “clock” in that link is a clock at all, but some kind of controller with settings from 1 to 10. Notice the lights all around the perimeter? As I recall that scene from seeing the movie ages ago, the character seen in the picture holding the “clock” hands had to keep moving the hands to where a light was flashing, and he got worn out because the lights were flashing too fast for him to keep up.

Not just a hodge podge : a *regional *hodge podge. That is to say, there were any number of weight & volume systems being used all over the place, some overlapping, and some using the same word for different measures. This obviously made commerce a pain in the arse.
Same went with money - many towns were still on the “we stamp our own coins” system, having earned the privilege from the King at some point in the Middle Age for some reason or another ; and you had to have change stations everywhere to turn your, say, Avignon pounds into Marseilles denarii and, again, it made commerce a bitch (not to mention many moneychangers were crooks).

The hour system however is a bit of a different story : medieval hours were Church hours - vespers, matines and so on. And obviously Revolutionary France couldn’t be having with no churchy bullshit, so, decimal time. It didn’t catch on, and neither did the calendar (because while the city bourgeois who came up with those schemes were fine with them ; peasants reckoned most agricultural tasks by Roman calendar dates and saints’ days and simply stuck with those)

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.

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.

Decimal time does survive-- sort of-- and is actually used in certain astronomical formulae and records in the form of Julian days, though I am not sure whether there is any link to French revolutionary or earlier uses of decimal time. A “Julian” date of xyz.25 indicates a quarter of a day past noon, or 6 p.m. Universal time, for example, and xyz.1 is 2:24 p.m. Even Microsoft Excel handles time in a similar way.

As this is general questions I need to correct this, the choice of base 10 is convention and not due to it being “scientific and logical”

Out time is based on Babylonian numbers which were base 60, which is a “superior highly composite number”

Or with less math…60 is evenly divisible 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

360 degrees, which the Babylonian also used for degrees is also a “superior highly composite number” and when divided by 15 = 24…or the number of “hours in a day”. Now the Babylonians tended to divide small segments of time into ‘ush’ which are 4 minutes and 60 / 15 = 4.

So note here we have the “superior highly composite numbers” when divided work out to

360 degrees / 4 seasons / 3 = 30 days in a year
360 degrees rotation / 15 ( 5 * 3) = 24 hours in a day
60 / 15 (5 * 3) = 4 minutes in a ush

365.256 sidereal year is close to 360 days in a year, and because is is easy to count to 60 on your fingers (if not as easy as 10) it is quite clear that to claim that the move to decimal was due to it being “scientific and logical” is unfounded. In fact it is one of the most scientific if you consider the amount of observations involved and the relation to pi and orbits. Note how they liked what are prime numbers when making that pi relation again.

That said, deciding on conventions is important as the are efficient and prevent errors and as by the time the French revolution happened society was using a decimal number system. I am not anti-Metric, but the unification of conventions is the main value and that is very valuable.*

There is a huge value in standardizing as much as possible but there is a challenge when 60 and 360 are both Colossally abundant numbers and Superior Highly Composite Numbers compared to having a divisor within the base numbers in this case for the critical users.

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).