Changing standards and definitions, including several best forgotten

After the controversy of recent weeks with bashed bridges, furlongs and novel signs, we turn to something deadly dull – the definitions of length, mass (or weight) and capacity (or volume) and their relationships.

The earliest civilisations, the Sumerians, the Egyptians, the Greeks and Romans, all developed metrological systems, and central to those systems were standards of mass and length, traditionally a metal block or cylinder and a metal rod from which copies could be made as and when required. But what about the standard for capacity, which could be based on either length or mass?

It might seem that length is the obvious choice, and indeed the US gallon is derived from the English gallon of 1707, defined as a cylinder seven inches in diameter and six inches high, giving a volume of exactly 231 cubic inches (pi was assumed to be 22/7).

Ah, ha! Not so fast. When the Secretary of the Royal Society, John Wilkins, made proposals in 1668 for a measurement system based on a universal measure of length he suggested that the standard of mass be “this cubical content of distilled rainwater”. This “cubical content” was his proposed standard of capacity, which came from his proposed universal measure of length cubed. This idea, linking mass to volume, would appeal, but in different ways, to the founders of both the metric and Imperial systems, bringing benefits and problems to both.

The fathers of metric system set out in 1793 to define the grave, as the kilogram was then known, as a cubic decimetre of rainwater weighed in a vacuum at the melting point of ice. But for the standard, they reverted to a traditional metal cylinder. The original prototype kilogram, manufactured in 1799, had a mass equal to that of 1.000 025 litres of water at 4°C.

Britain too was beginning to realise that its chaotic collection of measures was no longer fit for purpose. In 1819, a Royal Commission was appointed to consider the issue. The Commission included polymath Thomas Young, who favoured rationalising existing measures rather than adopting the decimal metric system, and this view prevailed. However, in its first report, the Commission made this recommendation:

“… on account of the great convenience which would be derived from the facility of determining a gallon and its parts, by the operation of weighing a certain quantity of water, amounting to an entire number of pounds and ounces without fractions, we venture strongly to recommend, that the Standard Ale and Corn Gallon should contain exactly ten pounds Avoirdupois of distilled water, at 62° of Fahrenheit, …”

The recommendations of the Commission led to the Imperial system of measures, but also to the divergence of UK and US measures of capacity.

This Imperial gallon, not to be confused with its US counterpart, would also cause a headache for metrologists, as the definition that applied up to 1976 indicates:

“a gallon is the space occupied by 10 pounds of distilled water of density 0.998 859 g/mL weighed in air of density 0.001 217 g/mL against weights of 8.136 g/mL.”

Meanwhile, the Bureau International des Poids et Mesures (BIPM), the international body set up in 1875 to ‘maintain’ the metric system, was trying to ensure a precise 1:1 relationship between capacity and mass. From 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density and standard pressure, which gave a volume of 1.000 028 dm³. It is now defined as one cubic decimetre.

Eventually, in 1976, the Imperial gallon was redefined as exactly 4.546 09 dm³. Twenty years later, it ceased to be legally authorised in the UK, although it remains in use for specifying fuel consumption, confusingly for any cars that also sell in the USA.

And what about the Imperial standards for mass and length?

In 1959, Australia, Canada, New Zealand, South Africa, the UK and the USA agreed on these definitions:

the avoirdupois pound is exactly 0.453 592 37 kg;
the yard is exactly 0.914 4 m.

In the UK, they were implemented in the Weights and Measures Act 1963. The traditional metal standards for the yard and the pound, dating back to the middle of the nineteenth century and in semi-retirement since 1898, were finally pensioned off.

And the standard metre and kilogram?

In 1960 the metre was redefined in terms of the wavelength of light, and the International Prototype Metre forged by Johnson Matthey in London in 1879 became a museum piece. Then, in 1983, this new definition was replaced by one based on the speed of light.

However, for mass, the International Prototype Kilogram, also manufactured in 1879 by Johnson Matthey, still reigns supreme from its home at Sevres near Paris. It remains the worldwide standard for mass. However, even that may be changing, as explained in this recent article:

So, John Wilkins, where does that leave us? Well, for a start there are some easy-to-remember relationships:

1 L of water has a mass of about 1 kg;
1 m³ of water has a mass of about 1 tonne; and, for example,
1 L of cooking oil of specific gravity 0.92 has a mass of 920 g;
the kids’ paddling pool, 1.5 x 1.0 m with water 120 mm deep, requires 180 L to fill it.

Other readers may be able to suggest areas where the switch from Imperial to metric measures of capacity has made life easier or safer for them.

The latest article from the Metric Maven in the US discusses some of these issues, but adopts a totally different approach:

40 thoughts on “Changing standards and definitions, including several best forgotten”

  1. @Ramsden:

    “Other readers may be able to suggest areas where the switch from Imperial to metric measures of capacity has made life easier or safer for them.”

    We occasionally go over to France and buy some wine. How much can my car carry? Well, after my wife and me and our luggage I have about 300 kg of load-carrying capacity available. Wine has a density almost exactly that of water (between 0.97 and 0.99% of water to be exact), so 750 mL of wine will weigh 0.75 kg to all intents and purposes. Add the weight of the bottle and the boxes (average 500 g per bottle), and that equates roughly to 1.25 kg per bottle. Ergo, 300 kg means I can load up 240 bottles. I can’t even think of doing that in Imperial!


  2. Well I think that was a very interesting article – thanks for that!

    There is just one confusing/confused/misleading piece I want to ask about though.

    This piece:
    “Eventually, in 1976, the Imperial gallon was redefined as exactly 4.546 09 dm³. Twenty years later, it ceased to be legally authorised in the UK, although it remains in use for specifying fuel consumption, confusingly for any cars that also sell in the USA.”

    Exactly what does “ceased to be legally authorised” mean and in what context is the use of the gallon illegal?


  3. @John Frewen-Lord
    You said “I can’t even think of doing that in Imperial!”. Let me give you a method. Weigh a bottle of wine, let’s say it is 2 3/4 pounds. You say you have 300 kg load capacity in your car, that’s about 660 pounds. Then, using your head, smartphone calculator, or whatever, divide the 660 by the 2.75 – just as you would the 300 by 1.25. I make it 240 bottles, the same answer as using your method! But I think my method was more straightforward than yours. 🙂


  4. @ Charlie P
    The article says: – “Eventually, in 1976, the Imperial gallon was redefined as exactly 4.546 09 dm³. Twenty years later, it ceased to be legally authorised in the UK, although it remains in use for specifying fuel consumption, confusingly for any cars that also sell in the USA.”
    I am not a legal expert, so I do not know if “not legally authorised” means it is illegal (as a primary measure).
    However, with your legal expertise you could read this stuff and educate the rest of us accordingly.

    The Units of Measurement Regulations 1995
    Made 13th July 1995
    Laid before Parliament 14th July 1995
    Coming into force 1st October 1995

    “ Part iv Units of measurement on and after 1st October 1995

    12. Subject to Regulations 13 and 14 below, the units of measurement and their symbols and abbreviations specified in Part iv of Schedule 3 to these Regulations are not authorised for use in the specified circumstances on and after 1st October 1995 (except as supplementary indications in accordance with Regulation 7).

    13. The units of measurement specified in Schedule 3A to these Regulations are, together with their symbols and abbreviations, authorised for use on and after 1st October 1995, but before 1st January 2000, in the fields of application specified in relation to them in that Schedule.

    14. The units of measurement specified in Schedule 3B to these Regulations are, together with their symbols and abbreviations, authorised for use on and after 1st October 1995 in the fields of application specified in relation to them in that Schedule.”.

    (5) For “(Regulation 8(2))” at the head of Schedule 3 there shall be substituted “(Regulations 8(2) and 12)”; for the heading of Schedule 3 there shall be substituted “UNITS OF MEASUREMENT WHICH ARE NOT AUTHORISED FOR USE IN THE SPECIFIED CIRCUMSTANCES EXCEPT AS SUPPLEMENTARY INDICATIONS”; …..


  5. I was unaware that the Imperial gallon was intended as a compromise between the prior ale and corn gallons. The prior corn gallon (times eight) is the basis of the US bushel and all US dry measure. That is why it is reasonably close to an Imperial bushel. Thanks for that tidbit.

    Most small two-cycle (two-stroke in the UK) engines require mixing oil and gasoline to a specified ratio. Unfortunately, you mix ounces of oil with gallons of gasoline. The factor of 128 fl oz/US gallon or 160 fl oz/Imp. gallon confounds the calculation. I find it easier to do the calculation initially in metric, measure the oil in milliliters, even though I have to convert liters to gallons of gasoline to buy it at the pump.


  6. @BrianAC
    That’s a cop-out, and what’s with the sneaky “illegal (as a primary measure)” caveat? In the original piece there was no such caveat, it said: “it ceased to be legally authorised in the UK”.

    All I’m asking (of the author preferably) is to know what he meant by “ceased to be legally authorised” and in what context is the use of the gallon illegal.


  7. Charlie P says: 2015-07-24 at 13:34
    That’s a cop-out, and what’s with the sneaky “illegal (as a primary measure)” caveat? In the original piece there was no such caveat, it said: “it ceased to be legally authorised in the UK”.
    As far as I know there is (are) no restrictions on supplementary units. From this I assume (yes it is only an assumption, maybe someone can tell me) there would be no legal reason why a garage could not advertise petrol in US gallons as a supplementary to litres. Or a cloth seller using ells alongside metres.
    If it is stated in this article as illegal then that clearly does not refer to supplementary measures and thus refers to the primary measure. That may well be flawed logic on my part yet again, I added it on the basis of my interpretation.


  8. @ Charlie P says: 2015-07-24 at 10:36
    @John Frewen-Lord
    You said “I can’t even think of doing that in Imperial!”

    Well I certainly could not even start!
    But then, why would anyone want to convert everything (or anything) to Imperial anyway?
    Apart from that it would also require one to know how to convert from metric to Imperial, us old folk would not know how to do that. I would have little idea how to convert 750 ml (cc to me) to pints, lbs or ounces, I have no idea except from these pages I have learned, much to my displeasure, that 1 gallon of water weighs 10 lb. (Thanks UKMA, I really did not need to know that). From the milk I buy, I also know 2 pints is 1.136 litres, (thank you Mr. Tesco, I really did not need nor want to know that either).
    Now standing in a French supermarket trying to convert all that …Why?


  9. @Charlie P
    This is a big subject and perhaps deserving another article, but I suspect MV’s readers would not thank us. Furthermore, I am not an expert in trading standards, in particular the changes in the law that occurred in 1995, so if what follows is wrong, I hope there is a Trading Standards Officer out there who will correct me.

    Section 7 of the Weights and Measures Act 1985 states:

    “7 Meaning of “use for trade”.
    (1) In this Act “use for trade” means, subject to subsection (3) below, use in Great Britain in connection with, or with a view to, a transaction falling within subsection (2) below where—
    (a) the transaction is by reference to quantity or is a transaction for the purposes of which there is made or implied a statement of the quantity of goods to which the transaction relates, and
    (b) the use is for the purpose of the determination or statement of that quantity.
    (2) A transaction falls within this subsection if it is a transaction for—
    (a) the transferring or rendering of money or money’s worth in consideration of money or money’s worth, or
    (b) the making of a payment in respect of any toll or duty.
    (3) Use for trade does not include use in a case where—
    (a) the determination or statement is a determination or statement of the quantity of goods required for despatch to a destination outside Great Britain and any designated country, and
    (b) the transaction is not a sale by retail, and
    (c) no transfer or rendering of money or money’s worth is involved other than the passing of the title to the goods and the consideration for them.”

    As a result of The Units of Measurement Regulations 1995, the gallon could no longer legally be used for trade. The Regulations also refer to “a provision of any contract, agreement, licence, authority, undertaking or statement made” and “a provision of any deed, instrument or document”. My understanding is that reference to the gallon in any of these would also be unenforceable in Court.

    The Regulations were intended to affect the substitution of metric for Imperial units for “economic, public health, public safety or administrative purposes”, and there has been some discussion lately as to how far the legal requirements go beyond “use for trade” – see an earlier article on MV:

    Of course, “gallon” can be used in conversation, perhaps for dramatic effect – “the pipe burst, and thousands of gallons of water poured into my basement”; in books, plays and films, perhaps to provide a period feel; in descriptions – “the drums for the steel band were made from 55 gallon oil drums”; and so on.

    But when the quantity matters, it would be as well to make clear which gallon is being referred to – the US gallon is still legally authorised in the US – and for younger audiences a supplementary metric conversion might be helpful.


  10. @ Charlie P:

    As BrianAC said, WHY CONVERT? The wine is metric (750 mL per bottle), my car’s carrying capacity is given ONLY in metric (kg), JUST WHY WOULD ANY SENSIBLE PERSON BOTHER TO CONVERT? What does that achieve? NOTHING! (Except a lot of extra work and the possibility of error.)

    For Imperial supporters to keep converting (and CharlieP you have left us in no doubt you are one), that just seems like utter stupidity. Thankfully, notwithstanding the likes of ARM et al, the world seems to show a bit more common sense.


  11. The truth is beginning to emerge, or at least it is being dragged out, but slowly. So, for the statement “legally unauthorised”, we should read “not authorised for use in the specified circumstances”. With those “specified circumstances” apparently being “for trade”, and even that has a very narrow definition.

    It would probably be clearer, and definitely be more honest to replace:
    “ceased to be legally authorised”
    “for certain specified trading purposes, had also to be accompanied by metric units to remain legal”.
    Or something like that.

    We certainly shouldn’t be using denialism to try to trick or fool the readers.


  12. @John Frewen-Lord
    You yelled ” WHY CONVERT?”.

    For one reason: because you gave your car capacity in kilos, for no other reason. It was you who said “I can’t even think of doing that in Imperial!”. I was showing you how. That was all I converted, I would have weighed a bottle of wine in pounds to cut out all the guess-work and unnecessary calculations and divided that into the capacity of the car.

    Now for your “For Imperial supporters to keep converting (and CharlieP you have left us in no doubt you are one), that just seems like utter stupidity.”
    1. You are confusing opposition to your methods with opposition to your goals. There is more than one way of skinning a cat, and the choice of a more efficient method than your own does not mean that the cat will not be skinned; indeed the choice of the more efficient method would mean that it is skinned more quickly and cleanly.
    2. I haven’t kept converting anything, nor suggested converting anything. The two systems are mostly used in different realms, metric where essential for work, imperial elsewhere, so conversion is rarely required.


  13. @Charlie P
    I fell at the first hurdle. In the French supermarket I had no way of weighing the bottle of wine in lbs. I guess you must carry a little fishing balance around with you.
    What other units are car capacities given in then? If you want to go back to the good old days, then car capacities were in cwt, that you would need to convert to lbs or stones or whatever.
    Apart from that, the fact is trying to calculate any given values in Imperial is far more difficult than the same calculation in metric, that is ‘probably’ why the world changed.
    Even given the two examples shown, metric and Imperial, without your sneaky bypass of trying to estimate the weight of the bottle, and of the effort to convert kg to pounds, I would say the metric calculations far easier than Imperial. That holds true for ANY calculation which in Imperial involves different units. That is the whole reason, for me at least, for changing to metric in the first place! I guess the rest of the world, outside the US, feels the same way.


  14. @Charlie P,
    ““for certain specified trading purposes, had also to be accompanied by metric units to remain legal”.

    Well, perhaps. A more honest statement might be “Metric is mandatory. Imperial is tolerated as supplemental information for old people who are determined to die before they learn metric.”

    I think you need to face that metric is required for trade, and as long as it is there, officials don’t care if you include Imperial or not. That says something powerful about the state of Imperial that you are in denial about.

    You’d love the US where, for a very broad class of products, BOTH SI and Customary are legally required. Although certainly metric advocates here are trying to kill the requirement for Customary and make it optional.


  15. @Charlie P
    You said, “I haven’t kept converting anything”. How then did you arrive at the value of 2.75 pounds for the weight of the bottle?

    You say that the bottle weighed 2 3/4 pounds. Where did the 3/4 come from? If I switch my digital scales to imperial I would get a reading in “lb oz” something like “2 12.0”. To obtain “2.75” it is necessary to CONVERT the ounces to pounds (by dividing the “12.0” by the number of ounces in a pound). You may find this straight forward and, in this example, you can probably do the conversion in your head, but many people can’t.

    If however, I weigh the bottle in kilograms I get a single reading in decimal that I can instantly input into a calculator without doing any preliminary conversions.

    To extend this scenario, imagine there were 3 different wine bottles, 2lb 13.4oz, 2lb 15.7oz, and 2lb 7.2oz. Using a calculator, how would you calculate the average weight in pounds and ounces?

    Answer: You would have to CONVERT the weight of each bottle into either ounces-only or decimal pounds, before adding the weights together, and dividing by 3. You would then have to perform further calculations to CONVERT the result back to pounds and ounces.

    Why bother, when you can simply weigh the bottles in kilograms, add the values together, and then divide by 3. All without the need for any conversions.


  16. Changing the argument to relieve boredom, maybe some Imperial fanatic could show me how to calculate BMI using stones and pounds and ounces and feet and inches. I know how USA do it (sort of). I want to see how we are supposed to divide our beloved stones and pounds by feet and inches. I am sure it is very simple as ‘everyone’ uses stones and pounds to weigh themselves and feet and inches to measure their height, yes it must be easy.


  17. I don’t endorse, but there are two ways of doing this:
    *Extend the weight to pounds, and height to inches
    *Use decimal stones and decimal feet (divide the odd pounds by 14, inches by 12)
    The problem is to deduce the “magic number,” the constant that fixes the units.

    For the first, which is American style, 0.453 592 37/(0.0254)² = 703.07
    For the second, 14*0.453 592 37/(0.3048)² = 4.8824

    Let us take a young women 112 lb or 8 st, 5 ft or 60 in
    703.07*112/3600 = 21.9
    4.8824*8/25 = 21.9

    Of course NHS would know she is 50.8 kg, 1.524 m, BMI = 21.9

    The numerator is the constant that converts the mass unit to kilograms, the denominator is the square of the conversion of the height unit to meters. I certainly wouldn’t say it was easy, and decimal stones would no doubt appall a Brit. I don’t have any idea how to do mixed based division, especially after squaring height.


  18. @ John Steele 2015-07-27 at 00:01
    I was hoping you would not be the first to reply! Yes, Americans can do it.
    I want to know how those in UK that measure themselves in those quaint old units cope with this.
    First there is the ingrained UK response, CONVERT EVERYTHING. That was always the irksome chore of any calculation, I can still see the maths teacher grinning whenever he said that. He was either a sadist or would rather be using metric. Reduce the quantities to a common denominator. Decimal feet? Don’t suggest that! You already know from the wine bottle it has to be a fraction, decimals are a no-go in the Imperial UK world.

    I doubt if anyone in UK would have any idea of the constant, even if they realised there had to be one, for converting the Imperial answer to the NHS BMI figure, which itself works only in metric.


  19. Clearly, when “incompatible” units are being used you have no choice but to convert everything so they become comparable (like finding a common denominator for fractions by finding the least common multiple).

    The beauty of the SI is that you don’t have to convert anything … all the units fit together with a minimal set of “orthogonal” dimensions (mass, time, etc.)

    Both elegant and easy as pie. What more could one want? 🙂


  20. @BrianAC
    I was giving a simpler method to show John Frewen-Lord that it doesn’t need to as difficult as he makes out. But as you seem determined to make it as difficult for yourself as possible, let me give you some tips.
    1. As the weights of bottles won’t vary that much, weigh a full one before you leave, in the comfort of your own home, with your favourite scales, and in the units of your choice. It is far easier than trying to remember the specific gravity of wine and estimate the weight of an empty bottle.
    2. Also, as the weight of your car, yourself, your wife and your luggage aren’t going to vary by a significant amount while you are away, why not go via a handy local authority weighbridge, and get an accurate weight for your laden vehicle. The chances are, this will be given in kg.
    3. Lookup the maximum laden weight of your car – again if it’s a recent model, this will appear in the handbook in kg.
    4. Subtract the laden weight in kg from the mlw in kg. This will give your available capacity in kg.
    5. If you chose kg to weight your bottle, then divide the available capacity by the bottle weight to get the maximum number of bottles you can buy. Subtract 10% to give a reasonable margin of error. If you chose lbs to weigh your bottle, double the available capacity weight of your car and divide that to get the maximum number of bottles with the 10% safety margin built in for free!

    Here’s a worked example.
    *Bottle weight: 1.25kg or 2 3/4lb
    *Car spare capacity: 300kg or 600lb (including safety factor)
    *Calc in kg: 300kg / 1.25kg * 0.9 (safety factor) = 216 bottles
    *Calc in lb: 600lb / 2 3/4lb = 218 bottles

    Mmm, looks like imperial is better – it allows 2 more bottles to be bought. 🙂

    @Peter K
    The 2 3/4lbs was arrived at by weighing a full bottle. I thought that more accurate, and easier, than estimating it. The scales said 2lbs 12oz, that is the same as 2 3/4lb. I could have stated it either way. To the nearest 1/4lb is perfectly satisfactory for this application. To get the average weight of 3 bottles I’d put them all on the scales to get the total weight, then divide by 3. In your example that would give 8 1/3lb. Divide that by 3 gives 2 2/3 + 1/9 = 2 3/4lb, as near as damn it. Mental arithmetic is sooo easy in imperial. 🙂

    Not that I’m any more an imperial fanatic than I am a metric fanatic, but I enjoy a challenge. If we assume that the desired result is in the metric-derived BMI units, rather than an imperial derived bmi unit, then, clearly, a conversion from one to the other will be required. But that’s only because the question is biased to favour metric, no other reason.

    The formula for the is (st*14 + lb)/(ft*12+in)/(ft*12+in) * conversion factor.

    E.g for a 16st-3lb individual of 6ft-1in height we get:
    (16*14+3)/(6″12+1)/(6*12+1) * conversion factor
    = 0.042597 * conversion factor
    = 0.042597 * 703.0696 = 30. 🙂


  21. Why is this even a cause of contention? Of course it’s easier to work out the BMI in metric measures. In the mean time, enjoy this metric version of an old song:

    My doll is as dainty as a sparrow,
    Her figure is somethin’ to applaud.
    Where she’s narrow she’s as narrow an arrow,
    And she’s broad where a broad should be broad.

    Just fifty-one kilos of fun,
    That’s my little honey bun!
    Get a load of honey bun tonight.

    I’m speakin’ of my Sweetie Pie,
    Just one meter fifty-five,
    Ev’ry millimeter’s dynamite!

    Her hair is blond and curly,
    Her curls are hurly-burly.
    Her lips are pips!
    I call her hips ‘Twirly’ and ‘Whirly.’

    She’s my baby, I’m her pap!
    I’m her booby, she’s my trap!
    I am caught and I don’t wanna run,
    ‘Cause I’m havin’ so much fun with honey bun!

    Believe me sonny!
    She a cookie who can cook you ’till you’re done,
    Ain’t bein’ funny!
    Sonny, put your money on my honey bun!

    So what has been gained – and lost – in the transformation? Well, Sweetie-Pie has been beefed up a little. Her BMI has risen from a scrawny 19.7 to a slightly more rounded 21.2. With that little extra padding she really can be broad where a broad should be broad. At 155 cm, she’s 2.4 cm taller but, she’s still petite, as the average 20 year old woman is about 164 cm. The biggest transformation is to change every inch packed with dynamite to every millimetre. So Honey Bun packs an even bigger punch!

    The original can be found at


  22. @BrianAC The “conversion chart” seems to be the Imperial users best friend when it comes to dealing with this sort of thing. Either that or the number of web-based or smart phone apps that take your measurements in imperial and then spit out the BMI without having to worry about it.

    IT is a tool that makes our lives easier… sadly it also makes us lazy in that we no longer have to think about such things which is probably part of the reason why imperial measures have lingered so long. Without access to technology I have no doubt that people would soon pick the system that was easier to work with.


  23. @Charlie P,

    BMI is commonly bandied about as though it were a unitless number. It isn’t. The numbers commonly referred to are actually quantities, a number times a unit, 25 kg/m² being the boundary between normal and over-weight. As the units are metric, it is inherently easier to work in metric. The “magic number” flows directly from the conversion of Imperial to metric for each variable. With metric mass and height, that step can be eliminated.

    Working directly in metric avoids 3 multiplies, 2 adds, and memorizing 3 conversion factors; that seems simpler. However, if the conversions are known, any system of measure could be used, including talents/cubit². But why not use the easy, worldwide one?


  24. @Michael Glass: So you feel the need to modify not only modern use of inch-pound measure, you also feel the need to change the lyrics of musicals from the ’50s?

    No doubt, there WERE in fact denizens extolling the virtues off ’51 kilos of fun.’. They were also, no doubt singing the praises of ‘Der Fuhrer’ or ‘The Emperor,’ or ‘Comrade Premier.’. They were not singing English, however. Another ‘advantage’ they were flying their aircraft in metres and droppig ordnance in kilogrammes. Perhaps you would have preferred a different end to the combat, which would have performed your desired cultural ‘improvement’ no doubt, in addition to several others. UKMA has also lamented Napoleon not conquering Europe, for similar reasons. Indeed, comrades, it is regretable to see Democracy repeatedly triumph over absolute rulers whose mandates on metrication would have been the tip of the iceburg!


  25. @ARM,

    So Anglo-sphere nations who use metric, like Australia, Canada, New Zealand only do so because they were overrun by Germans? Do you know what units the US Army uses (mostly due to our NATO allies). I do admit the US Navy and Air Force are less metric.

    So what does the rant say about your mandate for Imperial on the roads, vandalizing any use of metric you find (including legal dual signage as advertised on your own website, documented with photos). Your mission seems to be to deny the choice to use metric.


  26. ARM, what a fuddy duddy you are! You go on as if having a bit of fun with an old song is like supporting Hitler and Napoleon.

    Here then is something else to raise your blood pressure:

    My grandfather’s clock was too large for the shelf,
    so it stood ninety years on the floor.
    It was taller by half than the old man himself,
    though it weighed not a gram or two more.
    It was bought on the morn of the day that he was born,
    and was always his treasure and pride.

    But, it stopped, short, never to go again,
    when the old man died.

    Having apoplexy yet? Let me assure you that the transformation was well within musical tolerances. A pennyweight, Google informs me, is 1.55517384 grams, so “1 or 2 grams” is near enough.

    Still think I’m murdering the classics? No more than transforming the ell (45 inches) into a mile (63, 360 inches) in “Give them an inch and they’ll take an ell”

    Have a nice day, and do try to smile.


  27. @ARM:

    “They were also, no doubt singing the praises of ‘Der Fuhrer’ or ‘The Emperor,’ or ‘Comrade Premier.’. They were not singing English, however.”

    Good grief ARM, now you really are bordering on insanity! Next you’ll be saying that the Pope isn’t really catholic, and that Margaret Thatcher once worked for the Kremlin.

    To accuse someone (in this case Michael Glass) of wanting to live under a true and undemocratic dictatorship is an uncalled for insult to him, and would deserve an apology from any ethical accuser. But I doubt you are that ethical, and will resort to pseudo-legalese instead.

    What you are saying is that under a democracy, there can be NO laws at all! In other words, complete anarchy. That is of course complete nonsense. Even the most free of nations have very many laws, to ensure that the rights of individuals are balanced (and quite often nullified) by what’s in the best interests of society as a whole. In terms of legislating weights and measures, every single country in the world does it – no exceptions. And ALMOST every single country in the world – free democracies and oppressive dictatorships alike – legislates the metric system solely as its method of enforcing weights and measures, UK included (minor exception for road signs).

    To think you have some special right to flout those laws (as you have stated you do), shows you to be a danger to society as a whole. You may not like the metric system – that is your prerogative – but the law still needs to be obeyed. I don’t like speed limits, but I still have to obey them, and, as much as I don’t like them, I also recognise that they are there for the benefit of society as a whole. That is something that ARM obviously has yet to learn.


  28. @John Steele
    You addressed that remark to me? You are correct that BMI, as we know it, is measured in kg/m². I acknowledged that with my comment above: “If we assume that the desired result is in the metric-derived BMI units, rather than an imperial derived bmi unit, then, clearly, a conversion from one to the other will be required.” I used character case (capitalisation) to differentiate the two. The “bmi” derived from lbs and inches is lb/sq-in. The conversion factor I used to get from bmi to BMI was is 703.0696.

    However, in principle, lb/sq-in is no less valid as a measure than kg/m², in the same way that speed can be measured in mph or km/h.


  29. Well, let’s say, for a moment, that the metric system is being imposed from above on your country’s citizens… But what, then, about the old imperial system? Even more forced from above, historically, that one, being that in the past the “governments” usually were much less “democratic” (absolute monarchies, unrepresentative parliaments, feudalism, empires and so on) than today.

    So, the metric system, albeit of course still not perfect (it still has some historical inconsistencies, so to speak), would anyway always be more “free” – for today’s standards – than the older systems!

    But, anyway, measurement systems have very little to do with personal freedom(s) and instead very much to do with a modern common sense and the common good.

    … Returning more in topic, a rather strange thing is that the cubic decimetre was taken as the base for mass (kilogram) and volume (litre): it would have made more logical sense to take the cubic metre (tonne) as that base; at least, IMHO: YMMV – pardon, YKMV… 😉 🙂


  30. I read in the July-August Metric Today from USMA that the new definition of the kilogram can be expected in 2018.


  31. @ ARM: ‘UKMA has also lamented Napoleon not conquering Europe, for similar reasons.’
    When did UKMA that? As far as I know, never, because UKMA knows what Napoleon really did. If he had really conquered Europe, there would have been no metric system, because the Emperor was opposed to it. Under Napoleon France reverted in 1812 to the old units. The United Kingdom of the Netherlands (the present Netherlands, Belgium, Luxembourg) went metric from 1820 onwards under a law from 1816. No other country did so until 1840. In that year France went metric for good, and from now on country after country adopted it.
    Napoleon was on your side!


  32. @ARM
    ‘Der Fuhrer’ burned books to remove un-German ideas.
    ARM defaces or buries road signs they consider to be Un-British.
    Not a lot of difference in these actions I’m afraid.


  33. @@John Steele – The British Army used metric maps during World War I (the Belgians managed to get their master copies over to England in 1914 before the Germans took Antwerp). On seeing the superiority of metric units, the War Office decided to replace the existing yard-based grid with a metric grid. The resultant “Cassini Grid” was in place before WWII. In 1938 an alternative metric grid was in preparation. This newer grid replaced the Cassini grid after WWII and is the basis of today’s National Ordnance Survey Grid.


  34. @Han Maenen – not 100% correct. Napoleon might have disliked the metric system, but he saw the value of having one system of measure across the entire country, so he based the mesures usuelles on the metre and kilogram. Mesures usuelles were only used for retail trade.

    Before the Revolution, France has a myriad of units of measure – there might have been the “kings measure”, but this only applied to transactions that involved the king (ie royal taxes) – nobles, merchants, lords of the manor and others in authority were free to adapt units in respect of dues due to themselves or payments that they might make. In contrast, Britain had the concept of a single unit of measure across the realm (this concept was written into the Magna Carta in 1215). Thus, when in 1776 the American colonies declared independence, they inherited a system of measure that worked so the rank and file Americans were reluctant to accept a different (metric) system. In 1776 however, the coinage in the UK (and also in her colonies) was a mess, so the Americans quite happily created their own independent currency.


  35. @ Martin Vlietstra

    You are right of course, but I still think that there would not have been an international metric system if Napoleon had conquered Europe. The mesures usuelles would have been further developed and imposed on all conquered areas. The Netherlands, Belgium and Luxembourg were annexed to France in 1810 and the mesures usuelles were legally imposed on these countries. 1813 made short shrift of that. In 1819, just before metrication started, the usuelle standards deposited in the Netherlands were destroyed.
    By the way, the mesures usuelles and the US Customary units have in common that both are based on the metre and the kilogram, USC since 1893. ‘Usuel’ also translates to ‘customary’. It seemed at that time that decimal metric was going to follow decimal time and the Revolutionary Calendar towards oblivion.


  36. @H Maenen & Martin Vliestra:

    Mesures usuelles is much preferred to both USC and imperial and if USC and imperial were to be redefined along the lines of mesures usuelles more than half the battle would be won.

    When it come to measuring, people prefer round numbers in whatever system they use. Presently there is a disconnect between USC, imperial and SI. This is due to the unfriendly conversion factors that exist between units of USC, imperial and SI in which rounded numbers in one result in non-rounded confusion in the other. Who can ever be comfortable with increments and decrements of 25.4 or 0.45359237, just to name two.

    The US media in the 70s used scare tactics in their attack of metrication by insisting that common rounded USC units and sizes will not change but they would have to be expressed in new, strange numbers 10 decimal places long.

    Even when mesures usuelles was abolished it lived on and in some areas still does to this day. People still use the livre in the market. But this is not a problem because under mesures usuelles it was fixed to 500 g. The market uses a gram only scale and easily converts a livre to 500 g.

    You can’t stop people from wanting to use the old words, but what if those old words were turned into a mesures usuelles where they meant something more friendly in SI? If all ounces were 30 mL or 30 g, if the inch was 25 mm exactly and the foot 300 mm and the yard either 900 mm or 1 m, it would make it much easier to for us metric users to relate to what other people say when they use mesures usuelles.

    Would it matter if a pound was 500 g? This way those who insist in giving their weight in pounds would make it easier for us to think instantly of that value in kilograms. A person who gives their “weight” as 160 lb, we would know without a lapse of thought that they are referring to 80 kg. There would be no need for pound scales, only kilograms and those that “weigh” themselves in pounds and prefer to express it as so would simply double the number. A scale mass of 90 kg would be 180 lb.

    The battle between SI and USC/imperial will go on and on and nothing will be resolved unless there is a revision of USC/imperial into a mesures usuelles that makes the issue moot. I know most people won’t agree with this approach, but those same people are going to have to be frustrated for a very long time. Is that what we want?


  37. @ Daniel who wrote “Would it matter if a pound was 500 g? … A person who gives their “weight” as 160 lb, we would know without a lapse of thought that they are referring to 80 kg. ”

    The idea of adapting imperial measures to round metric numbers to enable the imperial names to continue in use is interesting but not new. What you of course would be doing is creating a further disconnect between the original imperial measures and the US customary measures that actually ‘do’ mean the same thing, like the ‘pound’, as opposed to those which do not mean the same thing like the ‘gallon’. I see no intrinsic value in having a ‘new pound’ of 500 g or a ‘new inch’ of 25 mm exactly. I don’t believe any country that has handled its metrication programme properly and seen it through to all areas of life (such as Australia) has gone done that route. You would effectively be creating another set of measures (the new imperial units as opposed to the old ones) and be generating even more potential confusion. It much makes more sense to get the actual conversion process over and done with and put the old names to bed. They will live on popular sayings and literature and the metric names will generate their own everyday expressions (like ‘k’ for kilometre, as in a 10k race).


  38. @Martin Vlietstra
    You said: “The British Army used metric maps during World War I”.

    That statement is contradicted here in an article about British Army WW1 Trench Maps. It describes how the British used the Belgian (and French) maps as a basis for their own, because the surveying had already been done, but it says: “The British squaring system was in yards instead of metres as in the Belgian and French maps it was based on.”

    Another point is that “Cassini” is the projection system that was used, not the grid spacing. The Cassini projection system was introduced in 1745 – half a century before the metric system was invented – and first used by the OS for their one-inch maps of 1805. The OS dropped Cassini projection in 1945 in favour of the Transverse Mercator projection system.

    The current National Grid is metric, not because of anything that happened in WWI, and certainly not because the War Office saw “the superiority of metric units”. Indeed a 5000-yard grid was used for the fifth series of one-inch maps (introduced from 1929). It wasn’t until the time of the 1938 Davidson Committee Report, which recommended that a single national grid should be used on all maps, that the idea of using the international metre as the basis for the grid was put forward.


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