Metrication matters - Number 9 - 2004-02-10
1 Feedback - notes and comments from readers
3 Oddities - measurements from around the world
4 Tips - pointers and methods to make your measurements easier.
5 Signs of the times
7 Q&A - readers' questions and answers
8 Rule of thumb
10 Hidden metric
A 'Metrication matters' reader, BJH, referred to the old ways of setting a standard rod, pole, or perch by measuring the combined left feet of the first sixteen men to leave church on Sunday morning. She suggested that: 'As the first men to leave church were probably aiming (quickly) for the best seats in their nearby ale house ... it is highly probable, though not now measurable, that some of the sixteen, in their haste, omitted to touch ground (on leaving church) and so the actual historical measure of the (rod, pole, or) perch might have to be reconstrued'.
Often we muddle metrication changes with language changes. We all know that there is a difference between mass and weight; anyone who has seen people floating around in spacecraft knows that someone can lose all of their weight, becoming weightless, while they retain all of their body mass. In SI units, mass is measured in kilograms and weight is measured on newtons. Although Isaac Newton (1642 - 1727) clearly distinguished between weight and mass some 300 years ago, many people are still struggling with the difference in words between these two ideas. At its heart, this is a change in language, specifically in the meanings of the two words, mass and weight. This change may yet take some time to be fully resolved (only 300 years so far), although terms in the modern vernacular such as 'Body Mass Index or BMI' will probably have an effect.
On recently made cars, in the USA, a speedometer scale is provided that contains a scale for kilometres per hour (km/h). So drivers in the USA have metric scales on their speedometers, but no metric speed limits.
Air Conditioning in cars: – You can check the efficiency of your car's air conditioner by noting the maximum temperature difference it can produce. It should be able to produce a difference of about 15 °C between the outside and inside temperatures.
5 Signs of the times
This is a repeat of an item that appeared in an earlier 'Metrication matters', but in the earlier edition I left out the words 'English-speaking' from the last line.
The metric bible, 'Le Système International d'Unités'* says in the preface to English translation of the 7th edition, 1998: 'A point to note is that slight spelling variations occur in the language of the English-speaking countries (for instance, "metre" and meter", "litre" and "litre"). In this respect, the English text presented here follows International Standard ISO 31 (1992), "Quantities and units".'
The British reprint of the above brochure bears the name of Chester H. Page of the (US) National Bureau of Standards as an editor, while the US reprint of the brochure does not. That was because the (US) Government Printing Office insisted that US spelling must be -er and Chester Page refused to allow his name to be associated with the change.
So far as I know, the USA is the only English-speaking country that uses the -er spelling.
- You can obtain your own free copy of 'The International System of Units SI', known as the metric bible, from http://www.bipm.org/
Always remember that you are absolutely unique. Just like everyone else.
Margaret Mead (1901/1978)
Q: Carl Sorensen asked: 'Pat, you said in an edition of the metrication matters that almost all airplanes fly lower than 8500 meters. I don't think this is right. I think commercial planes usually fly at higher than 10,000 m. I was on a JetBlue flight from Salt Lake City to New York, and the altitude was given to us as ... 11,200 m.
A: Carl and I are both right (sort of). Most planes are small planes and these are the ones that fly lower than 8500 metres. However, commercial aircraft, which are lesser in numbers, fly at altitudes above 8500 metres.
8 Rule of thumb
Baby animals: – Keep baby animals at 35 °C until their eyes open. After that lower the temperature by 3 °C a week until you get to room temperature. At 20 °C this will take five weeks.
By the way, I am always on the lookout for 'Rules of thumb' to add to my collection. I prefer metric ones but I also convert 'Rules of thumb' from old units to SI units. Please send your 'Rules of thumb' to
In 1790 on March 9, a French politician, Talleyrand, in proposing measurement reform, listed 182 measuring units that were currently in use in France. The unit names were:
- aune, canne, and pied for measuring length;
- livre for measuring mass; and
- anée, bichet, boisseau, carte, charge, emine, mine, muid, razière, sac, septier, tonneau, barrique, baral, quartaut, queue, velte, and pot for measuring volume or capacity.
Each of these unit names had at least two definitions. For example, the aune had 18 different definitions varying in size from 677 millimetres to 1191 millimetres; the livre had twenty different definitions that varied from 344 grams to 519 grams; and the boisseau had 25 definitions from about 2 litres to 102 litres.
10 Hidden metric
Recently, I have been reading some woodworking project books. I use the local library and so my references come from all around the world. It is interesting to see that many writers of these books are obviously doing their design and prototype building using millimetres as their basic measuring unit, and then translating their finished design into inches and fractions of inches so that their book might be able to be sold in the amateur woodworking market of the USA.
Pat Naughtin is a writer, speaker, editor, and publisher. Pat has written several books and he has edited and published many others. For example, Pat was the lead writer of 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.
Copyright notice: © 2004 Pat Naughtin All rights reserved. You are free to quote material from 'Metrication matters' in whole or in part, provided you include this attribution to 'Metrication matters'. 'This was written by Pat Naughtin of "Metrication matters". Please contact for additional metrication articles and resources on commercial and industrial metrication'. Please notify me where the material will appear. Copying for any other purpose, whether in print, other media, or on websites, requires prior permission. Contact:
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