# 24-hour clock

**URL:** <https://boards.straightdope.com/t/24-hour-clock/109264>\
**Category:** Factual Questions\
**Created:** [May 15, 2002, 8:44pm UTC](https://boards.straightdope.com/t/24-hour-clock/109264 "2002-05-15T20:44:45Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![regnad\_kcin](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@regnad\_kcin](https://boards.straightdope.com/u/regnad_kcin)\
**Post date:** [May 15, 2002, 8:44pm UTC](https://boards.straightdope.com/t/24-hour-clock/109264/1 "2002-05-15T20:44:45Z")

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Who came up with this idea?

I assume this time system, which appears to be pretty arbitrary, has been imposed upon the world. What were Asian countries using before adopting the 24-hour clock? When did, say, Japan adopt it?

Has anybody seriously considered a metric clock? Was it considered by the French revolutionaries who developed the metric system and reset the calendar?

RK

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**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\
**Post date:** [May 15, 2002, 9:18pm UTC](https://boards.straightdope.com/t/24-hour-clock/109264/2 "2002-05-15T21:18:25Z")

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Sure enough, the French had a [ten-hour](http://webexhibits.org/calendars/calendar-french.html), 100,000 second day. I have seen a few pictures of ten-hour clocks, but unfortunately I can’t find one.

Curiously enough, Fritz Lang chose to [incorporate](http://fledge.watson.org/~mccann/Metropolis/Machines/Clock.html) the idea into his film _Metropolis_.

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [May 15, 2002, 9:35pm UTC](https://boards.straightdope.com/t/24-hour-clock/109264/3 "2002-05-15T21:35:47Z")

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The French calandar also had twelve months of 30 days each, followed by 5 or 6 additional days sprinkled throughout to make it 365 or 366 days. Each month was divided into three weeks of ten days each, which was a very unpopular idea because only one day in ten was considered a “rest” day as Sunday is in the traditional system.

A metric second is 0.864 regular seconds.

I always prefered the [Discordian calendar](http://nuzban.wiw.org/wiki/index.php?Discordian%20Calendar), which has five months of 73 days each, and one leap-day.

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**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\
**Post date:** [May 15, 2002, 9:38pm UTC](https://boards.straightdope.com/t/24-hour-clock/109264/4 "2002-05-15T21:38:52Z")

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Here is everything you want to know about [**time**](http://library.thinkquest.org/28906/time_measurement.htm).

For example:

> [@](#):
>
> Five thousand years ago, Sumerians in the Tigris-Euphrates valley in today’s Iraq had a calendar that divided the year into 30-day months, divided the day into 12 periods (each corresponding to 2 of our hours), and divided these periods into 30 parts (each like 4 of our minutes).

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**Author:** ![Swede\_Hollow](https://avatars.discourse-cdn.com/v4/letter/s/3bc359/32.png) [@Swede\_Hollow](https://boards.straightdope.com/u/Swede_Hollow)\
**Post date:** [May 16, 2002, 12:13am UTC](https://boards.straightdope.com/t/24-hour-clock/109264/5 "2002-05-16T00:13:29Z")

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I had heard that the 24 hour clock came first and the 12 hour clock came later when mechanical clocks became the norm. (As James Burke said when refering to Big Ben “Can you imagine striking 24 on one of these?”)