# 10-10-10. A reason for celebration

For many in Britain, the metric system and decimal measures are the same. Sunday’s once-in-a-century date provides an opportunity to consider the link between the two.

Since 1983, Metric Week in the US has been celebrated during the week that includes 10 October. It enjoys the support of the National Council of Teachers of Mathematics, recognising the way decimal measures facilitate the teaching of maths (or math, depending on which side of the Atlantic you live). And this year, the USA Science and Engineering Festival runs from 10 to 24 October, emphasising the link between science and engineering and decimal measures. As far as is known, no celebration is planned in the UK on 10 October – there may be those who would prefer to mark the anniversary of 12-3-1760.

Decimal relationships have in the past been the most controversial feature of the metric system. The Dozenal Society of Great Britain still argues in favour of a multiplier of twelve. Others say that ‘natural’ measures are more important: the size of a barleycorn or a man’s foot, the distance from King Henry I’s outstretched thumb to his nose or the area a horse can plough in a day. They believe ‘natural’ measures should govern the relationships between units of measurement. And there are others who prefer to be left to use the measures they are familiar with, no matter how complex, irrational and parochial these may be.

So how is it that preference for powers of ten is now possibly the most important feature of the world’s most widely used system of measurement?

The Age of Enlightenment produced some of the first suggestions for rational systems of measures. Bishop John Wilkins in England (1668) and Gabriel Mouton in France (1670) both proposed decimal systems of measures based on a universal standard of length. Mouton’s ideas were taken up by the French Academy of Sciences, and, as a result of revolution, people in France and then elsewhere in continental Europe had the opportunity to try them out. Old habits die hard, and the experiment was abandoned in 1812 – Napoleon had other more pressing matters on his mind. Reversion to the old measures was not possible – contemporaries estimated that under the cover of eight hundred names, ancien regime France contained a staggering 250 000 different units of weights and measures. So a compromise between traditional and metric measures was devised, known as mesures usuelles, which was based on metric units of measurement but used familiar subdivisions and multiples. Thus two metres became one toise equal to six pieds each equal to 12 pouces, and one kilogram became two livres each equal to 16 onces. The decimal principle had been dropped!

Even the founders of the United States hedged their bets with the world’s first decimal currency, which has cents and dimes, but also quarters.

Today the metric system, predominantly decimal, is the primary measurement system in 98% of the countries of the world. How did it survive the initial setback?

Before the French Revolution, the diversity of measures in the Low Countries had long frustrated administrators. Occupied during the time of Napoleon’s Empire, Holland, Belgium and Luxembourg had for a while enjoyed the benefits of a unified system of measures. Collapse of the Empire threatened complete metrical chaos. King William I of Orange saw the benefits of central administration of measures for a nation relying on trade, and ordered the decimal system of measures obligatory throughout the Low Countries by 1820. Uniformity, rather than simplicity, was his primary consideration.

France did not rejoin the metric nations until 1840.

Other factors aided the spread of the metric system in Western Europe, in particular in Italy and Germany. In Italy, the adoption of a common measure pointed towards the creation of an Italian nation state. Piedmont and Sardinia were the first to follow France in declaring the metric system obligatory in 1850. Over the next decade, other Italian city-states followed suit. In Germany, facing unification under the domination of Prussia, the metric system appealed to many of the German states because it favoured none. Prussia wanted the industrialised, prosperous, western states to agree to unification willingly. It agreed not to impose its own measures and instead to adopt the metric system as the natural, neutral standard sanctioned by science.

So far, the enactment of the metric system had followed from the political considerations of governments. These paid little regard to the needs of the governed, who would have to switch from the familiar to the new. Yet the subsequent popular adoption of the metric system followed quite a different pattern; it accompanied the expansion of networks of communication, transport, trade and education. Now the system’s principles of simplicity and logic, and those controversial decimals, became crucial to its widespread and often swift adoption. Particularly in the twentieth century, when the system broke out from its heartland of the countries of continental Europe and their present and former colonies, simplicity became important if governments were to persuade reluctant electorates to follow their lead.

There are still many obstacles to the metric system becoming, as its founders intended, ‘for all people, for all time’, and these are frequently discussed on Metric Views. However, decimals have become respectable at last and the metric system’s decimal principle, a handicap two centuries ago as we have seen, is now never seriously challenged. (I am not sure, though, whether we should welcome the decimal inches, not fractions, used to describe the screens of digital cameras, notebooks, laptops, monitors and TVs).

To the organisers in the USA of Metric Week and the Science and Engineering Festival, Metric Views sends greetings and good wishes, and hopes that success accompanies your efforts on 10-10-10 and the days thereafter.

(Metric Views acknowledges the assistance of “The measure of things” by Ken Alder, Abacus 2004, in the preparation of this article.)

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### 24 Responses to 10-10-10. A reason for celebration

1. Jonty Stern says:

I thought the Russians had the first ever decimal currency back in 1705?

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2. A says:

Russia was the first country to introduce the decimal currency system according to the source on Wikipedia.

What happened on 12-3-1760?

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3. John Frewen-Lord says:

Looking at the various date formats, both in the article and in the replies. this would be a good time to standardise on the YY-MM-DD format. That way, there is no confusion between the MM-DD-YY date format used in the US and the DD-MM-YY format used in the rest of the world.

I notice I get ever more documents and communications using the YYYY-MM-DD format, especially in online financial transactions and the like, so it looks as if more and more organisations sre turning to this format to avoid confusion.

The 10-10-10 date of course works in all formats (and so will 11-11-11 next year and 12-12-12 the year after, but not after then).

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4. Ken Cooper says:

"What happened on 12-3-1760?"

Thomas Arne celebrated his 50th birthday.

Arne is most famous for composing the music to "Rule Britannia!"

"Rule Britannia!" originally included the famous "lost" 7th verse which set out the easy-to-remember relationships between the various units of the imperial system 🙂 🙂 🙂

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5. Seares says:

What happened on 12-3-1760? -
We got inches-feet-yards (in something)
Date Formats: Advantage of YYYY-MM-DD for computer use is that files on a given subject in a folder arrange themselves in chronological order- as long as the date is the only thing that alters in the titles. I use this system for logging minutes of meetings as it makes it easy to find any given date. (like they are listed in this forum)

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6. John Steele says:

Not YY-MM-DD; that gives 10-10-10 three possible interpretations (obviously not a problem when all the fields are 10). That confuses everyone. Even ISO 8601 has dropped any short forms with two digit year. The required form is YYYY-MM-DD (the hyphens may be omitted). If the year is outside 0000 - 9999, a plus or minus sign is required.

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7. Mike Joy says:

I have changed my letter template in my computer so that all future correspondence will automatically have a 'yyyy-mm-dd' date format at the top.
No more will Americans wonder if 7/10/2010 means July 10, 2010 or not.

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8. Martin Vlietstra says:

Edinburgh has a "Royal mile". London has nothing. One good candidate for the "Royal kilometre" is The Mall (which is one kilometre in length).

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9. Richard Ational says:

The internationally recognised format for the representation of dates and time is governed by ISO 8601:2004. Visit http://www.iso.org/iso/date_and_time_format for details.

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10. Peter K says:

If “Rule Britannia!” had a verse setting out the relationships between the various units of the imperial system, it must have been a heck of a long verse.

Here's just a few of the numbers it would have needed ...

Length
12, 3, 36, 6, 16.5, 22, 80, 1760, 5280

Weight
437.5, 16, 14, 20, 2240

Volume
34.678, 20, 2, 4, 8, 27, 1728, 49.833, 5451776000

I admit that I had to look these up as, unlike some, I don't find these values easy to remember at all.

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11. Percy says:

I haven't a copy of the latest edition of ISO 8601, however in the first edition 1988-06-15 it shows for Complete representation in the Extended format: CCYY-MM-DD.
C represents the century component.

I cannot see ISO examples that use four Y's.
I cannot see ISO examples that use a '/' instead of a '-'

So has 'YYYY-MM-DD' been made official, or is it just another variation from the International Standard?

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12. John Steele says:

Percy,
YYYY-MM-DD is official (or without hyphens) in the 2004 edition.

The CC for century has been dropped along with any 2 digit year representations. "/" is not permitted as a date separator. It is used as the separator for the two elements of an interval.

I discarded prior versions, so I can't determine the history of this change

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13. John Steele says:

Percy,
I was able to do some backtracking from draft files maintained at the ISO8601 Yahoo group. In early drafts for the second edition, the CCYY concept was retained. However, somewhere in the draft process, it disappeared. The final (2000) draft for the 2nd edition replaced it with YYYY, not even defining the "CC" term. However, the 2nd edition still allowed truncated two digit years.

The 3rd (2004) edition does not permit truncated two digit year. Expanded representations exist by mutual agreement for years outside 0000 - 9999. However, if the year is not (at least) four digits, it is not ISO8601. Happy 2010-10-10, everybody.

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14. David Brown says:

It is interesting that the discussion here has focused on the ISO date format. I use that format whenever I write a date because a single international standard appeals to me; just like the International System of Units. However, I only became aware of this date notation through my work in the IT industry. I have never seen it used in the media or in any government communications. Bizarrely, it seems to be the default on Microsoft’s flagship word processing package, but I frequently get asked why I’ve written the date like that. I think that this, the metric system and to a lesser extent the European emergency number (112) are all examples of how British leaders, and the British public they lead, are unable to make effective change. This does not auger well for the future, when the pace of change is likely to increase exponentially. As we have seen over the past couple of years, the world is a connected place and countries which can embrace change are the ones who will succeed in the future, with the laggards being left to pick up the scraps that the leaders drop for them.

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15. A says:

David - I don't think that the lack of change to the ISO date standard in Britain has anything to do with British leaders or resistance to change. Most countries use dd/mm/yyyy and Britain is one of them. Only one country uses yyyy-mm-dd exclusively and a few use a mix of the two.

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16. John Steele says:

Who uses yyyy-mm-dd exclusively? The US mostly uses mm/dd/yyyy, but there is some use of ISO8601, and Americans might recognize it better than the European dd/mm/yyyy format.

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17. John Frewen-Lord says:

Before the late 1970s, Canada used dd/mm/yyyy. When Canada metricated, official government policy was to switch to the YYYY-MM-DD format, though few in the private sector made such a switch. Lately, I have seen Canada, even at local government level, start to regress into the US mm/dd/yyyy format, and that is I suspect due to pretty well all computer software (including Windows) sold in Canada being set to US defaults. Official forms and documents (e.g. customs forms, provincial driving licences, etc) are all in YYYY-MM-DD format.

My Canadian cheques on my Royal Bank of Canada account are very explicit in which order you write the date - dd/mm/yyyy. In spite of that, my online bank statements show the date in American format, just to confuse things!

Interestingly, if you fill in a US customs form, the date is entered in separate boxes in DD, MM, YYYY order, so the US must use this format in some circumstances or at some government departments.

In terms of David's comment that this discussion has focussed on this issue, I would suggest that is because that is inherent in the title of this article - all about a date (albeit a special one). Notwithstanding all of the above comments, I go back to my original statement - in our very connected (metric) world, we do need to standardise on just one date format.

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18. philh says:

I image that most readers will have cottened on by now but just for the record the date '12-3-1760' is a wry comment by the author that supporters of imperial units might celebrate it in the same vein as we prometrics are marking 2010-10-10 i.e. purely numeric significance.

Fortunately they'll have to wait another 50 years for its tri-centenary 🙂

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19. philh says:

I strongly agree with the sentiment expressed above about date formats. The mixed use of DD/MM/... and MM/DD/... is very annoying.
I have come across software that uses MM/DD in textual output such as log files and there is no way for the user to change it!
Given that there is more than a 30% chance of confusion the problem is quite significant.

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20. John Steele says:

Philh,

I think 12-3-1760 is far less obvious to the Americans because we don't use yards much (except football). We are more likely to have memorized 5280 ft per mile, and have to work 1760 yds from that.

If countries can't agree on date order, perhaps required date format should include 4 digit year, YYYY, 3 alpha month, MMM, and 2 digit day, DD. Then order doesn't matter.

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21. David Brown says:

To John Steele's comment, the reason for not using alpha month names is that you then get a language dependency. Whilst a standard worldwide language may appeal for functional reasons (just like a standard set of units), the issue is, in reality, infinitely more complex. Language is not just used for measurement.
On A's comment that only one country uses the ISO date format exclusively, I don't know if that is true or not; but I understand that China uses this format. If that is so then it's 20% of the world's population on board with no conversion required.

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22. ‘John Steele, Who uses yyyy-mm-dd exclusively?’

I knew Japan did, Wikipedia suggests more.

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23. M says:

Here's another auspicious date 2010-10-20.

Apparently it's the 50th anniversary of SI (as defined by the 11th meeting of the CGPM held in October 1960).

http://www.bbc.co.uk/news/science-environment-11570173

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24. Martin Vlietstra says:

Both South Africa and Sweden use the YYYY-MM-DD format (or CCYY-mm-dd) if you are being pedantic.

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