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Metrication matters - Number 74 - 2009-07-10

Dear Subscriber,

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Metrication matters is an on-line metrication newsletter for you:

  • if you are actively involved in a metrication upgrade,
  • if you are planning a metrication upgrade, or
  • if you have a general interst in the metrication process.

You can read all previous issues at /newsletter when you scroll to the bottom of the page. You will also find useful resources for your inevitable metrication upgrade from the Metrication matters web page at http://www.metrictionmatters.com.htm


1 Feedback - notes and comments from readers 2 Editorial 3 Oddities - measurements from around the world 4 Tips - pointers and methods to make your measurements easier. 5 Signs of the times 6 Quotations 7 Q&A - readers' questions and answers 8 Rule of thumb 9 History 10 Hidden metric

1 Feedback

Duncan Bath from Peterborough in Canada wrote about the signs of the times item in Metrication matters 73 when I referred to the international date format (ISO 8601)


Was delighted to see this item (though not, strictly, SI) in your current Metrication Matters.

I have been fighting this (ad hoc date) windmill for over 40 years. The attempts (in a business context, in the public domain) to attempt to 'do' all-numeric dates in ad hoc ways are so irrational! My favourite example is 1/4/09. Assuming that the intended year is 2009, what's the rest of it - January 4th or April Fool's day?

You can read more about date formats in the article, Is 07 04 2007 The Fourth Of July? You can find this at: /docs/Is07042007TheFourthOfJuly.pdf

Mark Sugrue, from Ireland, wrote:

Hi Pat,

I live near Sixmilebridge in Ireland. Curiously, it isn't six miles from anywhere, being 14 km from Limerick city. It is possible that the name comes from the town being 6 miles by river from the Shannon River, or because it was, at some time 6 'Irish' miles from Limerick.

An 'Irish mile' was never properly defined, changing length from time to time and place to place. In the 16th century it was 20% larger than an English mile, but by the 18th century it had grown to 27% longer.

In the Irish language the town has a more sensible name- Droichead Abhann Uν gCearnaigh, meaning 'Bridge of the River of O'Kearney'. Far less confusing.

Mark in Ireland

John Frewen-Lord, from the UK, wrote to the USMA mail list to report:

Last week we were in Bournemouth, Dorset. We walked virtually the entire seafront between Hengistbury Head in the east to Poole in the west (a distance of around 10 km or so). Every 300 or 400 m there is a signboard showing nearest amenities, plus nearest point of interest. Everything was metric (e.g. Bournemouth Town Centre 2.5 km, Bistro Restaurant 120 m, toilets 85 m, cliff top elevation 48 m, etc).

Not an imperial measurement to be seen.

John F-L

Martin Vlietstra, from London, added a good line to the interesting blog at http://sobeale.blogspot.com/2009/07/your-modern-gop.html when he wrote:

How do you find the average of 4ft 11Ύin, 3ft 6½, 5ft 0Όin and 5ft 3in on a calculator or a spreadsheet? With difficulty. Try using pencil and paper? Why were calculators and spreadsheets invented?

Now try finding the average of 1.515m, 1.080m, 1.530m and 1.600m (the same lengths as above, rounded to the nearest 5mm) on a spreadsheet or calculator. You probably have a button to do it. Or don't you do math because you get so confused by customary units?

2 Editorial

Computers and metrication

The computer industry is possibly one of the most dangerous and implacable enemies the International System of Units (SI) has encountered. After 200 years of development of SI it is amazing that the home and personal computer industry are so addicted to medieval measuring units, while presenting themselves as being at the cutting edge of technology.

Clearly the computer industry is one of the main threats to the universal adoption of SI. Their practices in a number of areas seem clearly to be aimed at not only the reintroduction of old colonial units into the world but also the introduction of some measures the world has never seen before.

It may be that software writers are not actively working toward the destruction of fair and honest measuring standards. It may simply be that they are operating from simple ignorance. As you work with computer application programs, say an ordinary word processor, it soon becomes clear that the software writers have absolutely no knowledge of the International System of Units (SI) or of the metric system at all.

Although the appropriate unit for all printing measurements is the millimetre the computer industry has avoided the simplicity of using only one unit and instead has used the opportunity of metrication to make computer use as complex as possible. Again, to be fair to software writers, it could be that when they look at the world of typographers and the measures they use they might simply throw up their hands in horror (see http://en.wikipedia.org/wiki/Typographic_unit#Metric_units ) at the layering of jargon that they meet there.

On a computer there are always at least two methods for measuring – one group of measures for horizontal measures (inches, picas, centimetres) and several other groups for vertical measures (points, inches, centimetres). This means you need to learn different methods for measuring across a page as opposed to measuring up or down the same page. The complexities introduced by the computer industry include these practices.

  • They have introduced units, such as points, picas and inches, into areas such as schools and offices where they have never been used before, and where there is no need for them.
  • They have redefined the printers point so that the computer 'printer's point' and the printer's 'printer's point' are now not the same. This means that it is impossible to layout a pamphlet or a booklet on your word processor and be confidant that the layout will be usable by your printer – usually all the page layouts need to be completely redone by the printer (at your expense).
  • They have invented another new unit, 'dpi' to describe printer behaviour in a way that incorporates the low technology old units into the computer industry. Originally the Dutch company OCΘ made laser printers to a standard of 20 dots per square millimetre vertically and 20 dots per square millimetre horizontally. (You may recall that I mentioned this as 'Hidden metric' in the last newsletter.)
  • They are attempting to support the old 'cgs' units with their implicit support for the centimetre. If they had selected millimetres only there would be no need, either in page layout or printing for the use of a decimal point, making working in millimetres much more convenient as all measurements and calculations would only use whole numbers.
  • They have added the old inches and picas to a new kind of computer point for measuring letter sizes – using a new definition for computer use that is different to the point used in the printing trade for printing.
  • They have falsified the measure of computer disks on a regular basis. The now defunct 90 mm floppy had been relabelled in inches – very approximately – and the wrong measure was then built into operating systems so that a normal user could not change it back to the correct metric measure. This meant that an entire generation of school and college students all around the world had to erroneously learn that the size of the 90 mm floppy disk was 3 1/2 inches.
  • They have reintroduced fractions other than decimal fractions for use with computers. The favorites are sixths for use with picas, seventy-seconds to use with points, and the extremely strange use of quarters and eighths with centimetres! This has meant that schools have retained the unnecessary teaching of fractions other than decimals.
  • They have used inches to give the nominal size of computer screens – almost always inaccurately – and in some cases this has meant that the computer industry has had to lobby governments to change measurement regulations so that computer retailers can lie to us. A curiosity of this practice is that many sales staff use the old abbreviations ' and " interchangeably. If you see an advertisement for 17' monitors or 3.5' (90 mm) disks you might wonder how you get these things safely home and where you would find space to put them.
  • They are exporting the use of the old colonial units into nations that have been metric for years. It is now possible to buy a TV set or a USA designed computer monitor in the Netherlands with their size, in inches, written in French on the side of the box.
  • They attempted to impose non-standard formats for date and time formats on to the rest of the world by using default settings inside operating system software. These included the old a.m. and p.m. clock format and date standards that do not conform to ISO 8601 standards. This can be important for businesses that trade internationally as they often have to use computer software that does not include the international standard date format.
  • They have set the defaults in word processing software in the English language where it is now probable that any student, in any subject, in any school in Australia will complete the page layout using the default values set in inches. So even if a student is studying the history of the International System of Units (SI) it is likely that the pages will be laid out in inches or picas, and that the sizes of the letters will be selected in the new computer points devised by the computer industry to replace the printer's printer points.

The solution to all of these issues is quite simple. The computer software writers could agree to use millimetres for such things as page lengths and widths; millimetres for default margins and line spacing; millimetres for graphics programs; and micrometres for letter heights, widths, and kerning. The rule for how to decide between millimetres and micrometres would be: which provides whole numbers in the majority of cases. See the article, Whole number rule, at /docs/WholeNumberRule.pdf

3 Oddities

Education about the metric system has been highly ineffective in schools in the USA. For example, while the metric system is taught in science and mathematics classes this does not transfer to the sports fields outside the classrooms of the same school. Most high schools still describe school athletic events in the old pre-metric measures of yards for horizontal measures and feet and inches for vertical measures.

All this changes at the next educational level. When students arrive at college they then meet the rules of the National College Athletics Association (NCAA) that insists that field events be measured and recorded by students and administrators in metric units. The NCAA then encourages the dumbing down of the metric units into old pre-metric measures for the audience and the media using their own rather strange rounding rules that have different conversion methods for vertical jumps, horizontal jumps, and throwing events.

Carleton MacDonald and John M. Steele alerted me to this issue when they discussed a correction in The Washington Post (2009-06-05) on the USMA mail list.

A June 2 Sports article misstated the distance of Wilson High School junior Ibrahima Kebe's winning discus throw at the DCIAA track and field championships. Kebe's throw was 120 feet 11.5 inches, not 120 meters 11.5 centimeters.

The original article is at: http://www.washingtonpost.com/wp-dyn/content/article/2009/06/01/AR2009060103851.html

4 Tips – pointers and methods to make your measurements easier.

Metric conversion does not work in any reasonable time frame. Moving from a mindset based on inch-ounce measures to a mindset based on conversion factors between old pre-metric measures and metric units is simply not practical or productive. It has been repeatedly demonstrated that metric conversion is far too hard and it takes too long. See /metric_conversion.html

The best way to achieve metrication is by the direct route where you develop a new metric mindset without referring to old measures or conversion factors at all. Consider this approach:

  • Measure the width of the nail on your little finger. It is about 10 millimetres wide.
  • Measure the widths of each of your other three fingers. They are all about 20 millimetres wide.
  • Look at the width of your fist across the knuckles. It is about 100 millimetres wide.

Remember these and you can estimate short lengths quite readily using your own 'handy' references.

5 Signs of the times

Michael Quinion, in his excellent newsletter, World Wide Words, (see http://www.worldwidewords.org/nl/upja.htm ) reports on names given to bottles. Firstly he states that it's now illegal in the UK to use any of them except one. The only bottle name that's still allowed is 'magnum', which refers to a bottle containing two standard bottles or 1.5 litres. He then continues:

The remainder of the set, as usually quoted in reference books, are jeroboam (4 bottles/3 litres), rehoboam (6/4.5), methuselah (8/6), salmanazar (12/9), balthazar (16/12), nebuchadnezzar (20/15), melchior (24/18), solomon (28/21), sovereign (33.3/25), and primat (36/27). Some lists include the melchizedek, holding 40 standard bottles or 30 litres. The largest sizes refer only to champagne and are extremely rare, not least because it would be almost impossible to lift the bottles.

6 Quotation

Richard Phelps, of Iowa City, quotes the work of E. James Tew, the Director for Quality Assurance at Texas Instruments. Richard Phelps wrote:

In a 1985 study, Tew had two equivalent groups perform some paper-and-pencil computations, one using metric measures, the other using inch-pound measures. He found that the metric computations could be completed more quickly, in 44.9 percent less time.

As this almost doubles the costs of all calculations in the USA, it makes my estimate of the costs of non-metrication – at a bit more than a trillion dollars a year – look somewhat conservative (See /docs/CostOfNonMetrication.pdf ).

7 Q&A


Alan Young wrote:

Dear Pat

Thanks for the newsletter as usual. One question I have always wanted to know the answer to is: 'What units do aircraft pilots use internationally when flying around the world?' They always give us the height in feet, but surely they do not really use feet to communicate with ground control in all countries in the world?

A couple of weeks ago I went on holiday to Italy and managed to find a steward who said he knew the answer (I was not allowed to talk to the pilot for obvious reasons). He said that they did use feet all around the world but they took off the last two digits. In other words, they work in units of 100 feet. I was astounded! Do you know this to be true? And what units do they use for distances and air speed?

Are there any plans for metrication in this department?

Keep up the good work.

Best wishes, Alan Young


As I didn't know the answer to this question, I asked advice from Michael Payne, who is an aircraft pilot who regularly travels internationally. Mike wrote:

Hi Pat,

Yes we do use feet with some exceptions. I've tried to do some research into when all of this came about with little luck. Apparently in the early days of aviation after the first world war no one worried about altitude, there were not enough planes, and it was all visual flying (not in clouds or at night). When regular scheduled flights took place in the 30's Europe used meters and the English and Americans used feet. The latter won the Second World War and ICAO standardized things on feet.

What the gentleman was referring to is correct, we use feet when using a local altimeter setting (QNH is what it's called) up to a transition altitude (which varies) where we set the standard 1013 hPa and drop the last 2 zeros and call it a Flight Level. So if you are at 10 000 ft it's called Flight Level 100, 30 000 ft is FL300 etc. The Transition Altitude in Australia is 10 000 ft, here in the US it's 18 000 ft, in Mexico it's 20 000 ft. In Europe it varies and is normally 2 000-3 000 feet above each airport, generally the same the world over.

China, Russia, Mongolia and the former soviet republics still use meters for altitude with the exception of Eastern Europe who have all gone to feet to standardize with the rest of Europe. I personally think at some time in the future we'll all be flying meters but it will probably be in 100 m vertical intervals instead of the present 300 m intervals. We have the capability in our aircraft to press a button and get the altimeter to switch to meters. Bear in mind here we have what are called glass cockpits, everything is presented on a CRT or LCD screen and the actual altimeter picture is generated by a symbol generator.

The US transitioned to giving pilots Celsius temperature about 10 years ago, the next step may be to get everyone to use hPa, it's going to be a while to get altitude to feetis this correct? metres surely and the British will have to be totally metric for quite a time before everyone pushes the US to change.

Regards, Mike

8 Rule of thumb

If a baseball is pitched at 150 kilometres per hour (42 metres per second) it takes about 400 milliseconds (0.4 seconds) to reach the home plate. This is a high, but not a record speed; pitching speed records can be found at http://hypertextbook.com/facts/2000/LoriGrabel.shtml

9 History

A mediaeval suit of armour had a mass of about 25 kilograms.

10 Hidden metric

King Edward I, of England, first standardized shoe sizes in 1305. A shoe size was defined as the length of a dried barleycorns chosen from the middle of the ear, full and round. Do you carry a pocketful of barley when you visit the shoe store?


Pat Naughtin

Geelong Australia

Pat Naughtin is a writer, speaker, editor, and publisher. Pat has written several books and has edited and published many others. For example, Pat has written a chapter of a chemical engineering Encyclopedia, and recently he edited the measurement section for the Australian Government 'Style manual: for writers, editors and printers'. Pat has been recognised by the United States Metric Association as a Lifetime Certified Advanced Metrication Specialist.

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