View Full Version : History of the 24-hour day?

Cyberseeker

2013-Feb-28, 10:51 PM

Jesus answered, "Are there not twelve hours in the day? If anyone walks in the day, he does not stumble, because he sees the light of this world."

We date this statement to 29 AD and I would assume he is referring to the Roman method of dividing the day into 24 hours because the old Hebrew system was different.

It was a long time ago, so I have a question concerning the history of our clock. How much earlier than the Romans did we divide time into increments of 12 or 24-hours? Can someone suggest a starting point for when it came into general usage?

Thanks for any info. :)

Cyberseeker

grapes

2013-Feb-28, 11:05 PM

I believe the Sumerians divided the whole day into twelve parts. My personal theory is that they were dividing the month into 360 parts just like the year (divided into about 360 days), a thirty day month then.

When the Egyptians started using sundials, they kept the convention, but only during the day--sundials are notorious for lack of nighttime effectiveness.

Cyberseeker

2013-Mar-02, 07:04 AM

Thanks, it makes sense about 360 days being in the same pattern as 60 minutes and so on. I managed to find this link too. They seem to think Egypt was the first. http://curious.astro.cornell.edu/question.php?number=594

Someone told me that the Japanese had two 12-hour watches also. I wonder what it was about "12" that different cultures should come up with the same idea independently of each other?

silylene

2013-Mar-04, 03:45 PM

Base 12 counting systems were used in several historical groups across the Middle East, Tibet, Africa.

Perhaps it is because we have 12 fingerbones (count them!), all which could be touched by the thumb for counting on one hand.

2 hands = 24 hours.

grapes

2013-Mar-04, 04:51 PM

Base 12 counting systems were used in several historical groups across the Middle East, Tibet, Africa.

Perhaps it is because we have 12 fingerbones (count them!), all which could be touched by the thumb for counting on one hand.

More likely because it made whole fractional parts--half is 6, a third is 4, a fourth is 3, a sixth is 2. The only thing missing is a fifth, and that is solved by using base 60, which we did early on (and to this day).

2 hands = 24 hours.

I would say no, for two reasons. First, counting had gone beyond simple finger systems long before the adoption of the 24-hour day, and second, I can't imagine someone standing there slowly counting away the hours of a day using their thumbs and fingers. :)

silylene

2013-Mar-04, 06:02 PM

Yes, agreed on the fractional parts, and this is the obvious reason for twelve as we all know.

However I have a hypothesis (probably untestable unless we find a pre-historic counting stick) that goes like this:

I do think the original counting system of Homo far predates fractions and mathematics. Probably our first and earliest counting system originated at the latest with modern H. sapiens, if not earlier maybe even as early as H. erectus. Thus I believe that the original counting system predates fractions by at least a couple hundred thousand years. (And for that matter it predates 24 hours in a day too)

If you look at 'primitive' counting systems currently in use by at least a few of the stone age cultures, they are like this: one, two, three, many. No number after three.

Now if you count your phalanges, they are grouped by threes: one-three, two-three, three-three, four-three, total = 12. It's like a base three abacus. I think this could have been the first counting system, at least for some early pre-historical groups, as it matches well with the even earlier primitive one,two,three, many counting system.

The alternative counting system is to count fingers, grouped by fives, as one-five, two-five which gives total = 10 (the one-five, two-five system is how the Mayans counted)

Of course when the modern system is later settled on as 10 or twelve 9depending on the culture), and as math and fractions are figured out, then the counting base can be rationalized after the fact. Whether the modern counting systems (either base 10 or base 12) were created out of thin air because they were rational, or whether they stayed in use because they matched well with a pre-dated pre-historic practices (which is pre-fraction and pre-mathematical), I do not think we know.

Grey

2013-Mar-04, 10:03 PM

Your comments made me curious, so I went looking on the web to see what I could find. The oldest tally sticks (the Ishango Bone (http://en.wikipedia.org/wiki/Ishango_Bone), the Lebombo Bone (http://en.wikipedia.org/wiki/Lebombo_Bone), and the Wolf Bone (http://en.wikipedia.org/wiki/Wolf_bone#Paleolithic_tally_sticks)) known are from about 20,000 to 35,000 years ago. From looking at images of them, it's hard to piece out specific patterns. There definitely does not appear to be a tendency to group tally marks into groups, the way we often do now. For whoever made this, if they wanted 21 tally marks, they just made 21 lines, not 4 groups of 5 plus 1 more, or a group of 12 and a group of 9. There definitely doesn't seem to be a tendency with any of these things to group marks into dozens or anything like it.

But the Ishango Bone in particular has some very interesting groupings, including some that add up to 60. It sounds like nobody is exactly sure what these were used for, or knows what the significance of the numbers was.

profloater

2013-Mar-04, 11:08 PM

absolutely no evidence for this but one guess is as good as another. If I use my fingers to count I might close my fist for 6 and then use the other hand to get 12. If I want to communicate numbers a fist and fingers makes a good system, easy to see. The need to go over 12 is maybe rare. Just a speculation.

silylene

2013-Mar-05, 12:23 PM

Grey, thanks for looking up the tally sticks. I checked those references, interesting! The counting looked ungrouped.

The Chumash (http://en.wikipedia.org/wiki/Chumashan_languages) indians (San Diego area), Ventureno (http://en.wikipedia.org/wiki/Venture%C3%B1o_language) indians (SW US area) and the Kharosthi (http://en.wikipedia.org/wiki/Kharosthi#Numerals) (original inhabitants of the Stans in Asia) all used quaternary counting systems (base 4). Duodecimal counting systems were in original use in the Nigerian tribal areas of Africa and small parts of India.

The Yoruba in Africa, Bhutanese, Mayans and Aztec used vigesimal systems (http://en.wikipedia.org/wiki/Base_20)(base 20), as well as the Ainu and Basques. It is also a relic counting system among the Gaelic and Celtic languages, and has some traces in French.

grapes

2013-Mar-05, 01:46 PM

Yes, agreed on the fractional parts, and this is the obvious reason for twelve as we all know.

However I have a hypothesis (probably untestable unless we find a pre-historic counting stick) that goes like this:

I do think the original counting system of Homo far predates fractions and mathematics. Probably our first and earliest counting system originated at the latest with modern H. sapiens, if not earlier maybe even as early as H. erectus. Thus I believe that the original counting system predates fractions by at least a couple hundred thousand years.

If you mean subdivisions of the principle base, like we've been discussing, I'm sure that that's not so--such divisions were probably the second development beyond the idea of a base itself, and as I've said probably even influenced the choice of base. Counting off an integral number of groups and being able to divide that total into equal shares seems to have had almost universal appeal--meaning that the base is an even number. That's possible, too, with two hands, but not one. :)

Cyberseeker

2013-Mar-16, 06:35 PM

Thanks for all the ideas. Fingerbones, fractions etc. Yep, logical. It reminds me of the question of railway tracks. Someone tried to figure out why its unusual width and did a bit of research on the subject. Apparently the gauge is based on the width of a horses backside. :eek: because the gauge was based on ancient Roman roads in Britain which in turn were based on the grooves made by chariot wheels.

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