back to article Boffins mount campaign against France's official kilogramme

International boffins are mounting a determined diplomatic push to end the practice of measuring mass by reference to a 130-year-old metal cylinder kept in France, saying that the French ingot is no longer up to the job. The Consultative Committee for Units, whose chairman is Blighty's Professor I M Mills FRS, and which counts …


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  1. Stoneshop Silver badge


    Le Kilogramme is to walk the Planck.

    1. IglooDude

      leading to...

      Mass panic amongst the boffinry.

  2. Code Monkey

    Good call

    Thanks for the metric system and all. It whizzes on pounds and ounces from a great height.

    Now it's time to let go before the French "kilo" becomes as anachronistic as the comedy weights and measures it replaced.

    1. Number6


      Imperial units are good for random party pieces, such as asking people if they actually know the size of an acre (one chain by one furlong). SI units are boring in comparison.

      1. Graham Dawson

        It's all about factors

        The reason we use a 360 degree circle and 60 seconds in a minute are because of the factors you can get from this. A base 12 measurement system gives you more factors to work with than base ten, which gives you five, two and... ten. With base 12 you get five, two, ten, six and three, which is easy to understand when you're working with fractional mathematics. Fractions, I find, are more intuitive than decimal maths. Get a decimal point on the wrong place and you're out by an increasingly large factor. Get a fraction wrong and it's obvious immediately.

        By curious coincidence the length of a yard, and a foot (and consequently an inch) can be derived using nothing more than a time standard and the motion of the stars. Despite popular belief these measurements aren't based on some sovereign's oversized foot, which is why they're remained so constant for so many thousands of years (tens of thousands if you count the megalithic yard).

        This is the best page I could find describing the process:

        Now, the problem with imperial measurements isn't an inherent one: they lack standardisation, which isn't a flaw of the units but of the people using them. Many were derived from the existing basic units for use in agriculture, and others were modified to fit that use (the mile used to be 5000 feet long, the same distance as used by the Romans, but was modified under Elizabeth the first for some reason). The solution would be standardisation, which was never actually tried on anything other than an ad-hoc and contradictory basis (most of the criticism of imperial measurements is how ad-hoc they appear, which is true if you take the entire gamut of measurements grouped together under "imperial", many of which were taken from informal measures for various things but which aren't actually related to the basic units). If you go back and work from the basic measurement of the inch, foot and yard you could create a set of standard measures for weight, volume and length that would be far more versatile than base ten metric. It would be rather revolutionary.

        On the other hand metric can be converted between units counting on your fingers, if you're willing to give up some flexibility and a few useful factors. It's all about what you want to do with it.

        Advocacy over. :)

        1. Anonymous Coward
          Thumb Up

          I would add...

          I agree with all of that and I would add that the current metric measures also lead to unwieldy amounts like 498 ml cans of stuff which might have been measured imperially using single digits.

          Metric measures may be easier to calculate with arithmetically (being based on units of 10) but they don't actually make for handy numbers in real life..

          1. joylessdave


            that is the stupidy of the manufacturer for not adding 2ml and labeling it as .5L or 1/2L not the fault of the metric system

        2. Anonymous Coward

          Say whaaaaa!!!??

          "A base 12 measurement system gives you more factors to work with than base ten, which gives you five, two and... ten. With base 12 you get five, two, ten, six and three, which is easy to understand when you're working with fractional mathematics."

          Copy-paste fail, one presumes? But I have to ask... what were you hoping to save time on?

        3. Rombizio
          Thumb Down


          The metric system is the only one that can be used for accurate microscopic measurement. Also, the metric system is MUCH more intuitive since division by ten is easier than divisions by 12. You think the Imperial system is more intuitive only because it is the one you have been using. Try to measure the larvae of bed bugs on my laboratory using the Imperial system and you will never use it again in your life.

          Have said that, there is a reason why the Imperial system lacks standartisation: It is based on a very old method of measurement that has not evolved because it has no precision for scientific application. No reason to have two systems imo.

          1. David Cantrell

            Pointless title, which must contain letters and/or digits.

            "The metric system is the only one that can be used for accurate microscopic measurement"? Bullshit. Just like you can measure a billionth of a metre, you can measure a billionth of a yard. Your problem is simply that your tools are set up to provide easy access to SI units.

          2. Red Bren

            Your laboratory?

            "Try to measure the larvae of bed bugs on my laboratory"

            Do you mean your bed? What other experiments do you carry out? Actually, no! I don't want to know...

            Mine's the white one with the biros in the chest pocket.

          3. Anonymous Coward
            Anonymous Coward

            I don't know about you but...

            I count by adding one the previous number. It's simple and easy, even for me.

        4. Jimbo 6

          Factors / base 12

          @ Graham :

          Surely multiples of 12 aren't used much in Imperial weight systems (unless you're talking the 12 troy oz in a troy pound) - 12 is more commonly used in money calculations (12 pence in a shilling, 240 in £1) ?

          The main multipliers in the Avoirdupois weights system are 8 and 7 (16 oz in a pound, and 14 pounds in a stone - hence everything upwards is neatly divisible by 7 and 8). Why ? ~ because there are 7 days in the week, and the Roman army unit was eight men (as the British Army unit still is).

          So a hundredweight (112 lb) of wheat, for example, easily breaks down into 1 stone per man; if it has to last them a fortnight, they each have exactly 1 pound per day. One pound of meat = 2 oz per man, etc. That's where the metric system really falls down, just try splitting a ton of horse feed into 7 equal parts.

          (Also - IIRC - there is a theory that the Mesopotamians - from whom we get our 360 degrees & 60 minutes - used base 60 because they counted using each joint on each finger, not because they knew it could easily be broken down into factors. Though they may just have been clever bastards.)

          1. Anomalous Cowherd Silver badge

            Makes you think

            If only the author of Genesis had decided that god creating the world in 8 days instead of 7, we'd all be working on a base-2 system. 64 minutes in an hour, 16 ounces to a pound, 128 pounds to a hundredweight...

            And who wants to be a millionaire would be satisfyingly binary all the way up.

        5. Lukin Brewer

          Celestially inspired.

          Heh. The Mesopotamians and Babylonians also started western astrology. Most people are familiar with the 12 signs of the Zodiac. However, each sign (or house) was divided into three decans (because there are three signs ruled by each of the four elements, natch) and each decan was graduated into 10 degrees (for accurate recording of the positions of the planets - do keep up). 12 houses make 36 decans make 360 degrees. Simples! So much nicer than those dreary new grads, too.

          If it's ease of use (and factorization) that you want, I'd say go for a binesimal system: divide the circle in half, then keep halving the divisions until they come out small enough, like with a compass rose. How does a 512-degree circle (and a 128-degree right angle) sound? 'Cause, as any physicist will tell you, the only measure of angle that's scientifically meaningful is the radian, and I can't really see Joe Public getting to grips with that.

      2. Paul Crawford Silver badge


        Surly you mean good for jokes such as:

        Q: Why has an elephant got 4 feet?

        A: Because it would look silly with 6 inches!

        Thanks, its the one without the good joke book...

        p.s. If a child asks, its the trunk you are referring to.

      3. Telboy

        rods poles perches

        Surely you mean 160 Rods or is that poles or perches.

        All in fact are the same thing,

      4. bluesxman

        RE: Fun

        I realise we don't know each other, but for the avoidance of doubt -- please do not invite me to any parties.

  3. Harry

    So, how long will it be ...

    ... before the first spoof "official 1Kg weight" advert appears on eBay Nigeria ?

  4. Anonymous Coward
    Anonymous Coward


    ...if someone breaks in there and slices a bit off, will everything weigh more? It sounds like some crazy villain's plot to take over the world - when the kilogram weighs less he'll be able to get into some bank vault because the pressure sensors calibrated to 50 kilograms won't work anymore, etc etc...

  5. frank ly

    I am amazed

    "Elaborate precautions are taken to ensure that the kilogramme doesn't change mass - a complicated official cleaning procedure is carried out to remove atmospheric oxidants from the surface. "

    This is ridiculous. All they need to do is give it two coats of epoxy varnish and the problem is solved.

    1. TeeCee Gold badge

      Re: Sooo...

      He wouldn't need to get into some bank vault by devious means, accessing it in the conventional manner will do.

      1) Deposit 100 kilos of gold ingots in bank vault. Get receipt for same.

      2) Saw 30% off the standard kilo.

      3) Withdraw 100 kilos of gold from bank vault.

      4) Wait for new kilo definition issue to be resolved.

      5) Profit!

      1. Anonymous Coward
        Anonymous Coward

        Buy a few billion kilos of gold,

        And the gamble of switching might pay off.

        on second thoughts, probably just better off going to ladbrokes.

        1. Anonymous Coward
          Anonymous Coward

          And the rest of us would be laughing at you

          Cos gold is still measured (and traded) in pounds troy, not kilos.

          1. jonathanb Silver badge

            That is true

            however imperial measrements are now defined by reference to their metric equivalents. For example, the troy ounce is defined as being exactly 31.1034768g.

      2. JohnG


        Nice idea TeeCee but don't the banks measure gold by the Troy ounce?

      3. Yag


        If you deposit 100 Kg of gold, *reduce* the actual weight of the Kg by sawing off the standard Kilogramme, then withdraw 100 (new)Kg of gold...

        Won't you actually *lose* gold?

    2. Stoneshop Silver badge
      Thumb Up

      You may want

      to get hold of the Superdupont comic, the first album. Okay, it's about the meter, but one of the stories is quite like your plot.

  6. Anonymous Coward

    But surely...

    ..the measurement should be a gramme, not 1000 grammes

    1 Litre

    1 Metre

    1 Gramme.

    All other mesurements are derivitives of this.

  7. Robert Heffernan

    Does that mean...

    ... when a builder asks his apprentice how heavy those planks are, the correct answer is always 1kg?

    1. mspletz

      meters and liters and Kilos, oh my!

      > the measurement should be a gramme, not 1000 grammes

      The choice is somewhat arbitrary; just because gram doesn't have a prefix doesn't mean it is the basis for the unit. After all, a liter isn't really a base unit either, being a volume of 1 /1000 of a cubic meter... What determines the basis for the set is really just convenience.

      There are two basic SI 'sets' of units, the MKS set (meter, kilogram and second) and CGS (centimeter, gram and second). The MKS set is the most common, as it is a good set for 'ordinary' things such as cars, factories,etc. The CGS set is preferred typically by the nuclear boffins, as the smaller unit set aligns more closely with the smaller scales involved.

      1. Chemist

        "aligns more closely with the smaller scales involved..."

        Bit of a Hobson's Choice really - I don't think working with 1e-18 kg or 1e-15 g makes too much difference

      2. Daniel Evans

        A mere 7 base units and all (one per day of the week?)

        Although the Candela is unloved by most, and the Mole is slightly strange, as it's just a big number.

        1. M man


          7 Units 7Days.....hmmm thank god its Kelvinday.

      3. Charles Manning


        Naah, millimetres.

        Metric building/engineering plans are almost always in mm, even for "big things" like houses, cars and the like.

        Nuke boffinss will likely be dealing with far smaller units than mm. As soon as you start using exponents then you use metres: 55x10^18m. Nobody uses exponents with mm.

        Centimetres are just a low-brow measurement for "something about the same magnitude as an inch". Use them in any professional capacity (building trade, science, etc and you'll be marked as an impostor).

        1. Naughtyhorse

          marked as an impostor

          or of course an american, they do love their centimetre. dolts

          even better than that, in some states some utilities use imperial and others use metric, giving rise to such wonderful questions/statements as 'our 110kV cable runs 85m alongside the road, 3m from the kerbline, the 9 inch watermain joins out route 54 feet from one end and runs 12 feet 6 from the kerbline... so when we energise will there be a bang?

          metic is the only rational system, I had endless arguments with my old man about factors of this that and the other, and roman soldiers getting their bread for a fortnight. it's all bollocks.

          Any measurment system can me useful so long as there are human scale units in there - microfortnight, attoparsecs, or indeed the bulgarian airbag all work. though with a rational system you dont need to remember millions of factors to convert between them eg feet per second into miles per hour etc etc etc

          more interesting question is _why_ is THE kilo gaining weight whe compared to al lthe witnesses?

      4. Steven Jones

        SI Units

        If a bunch of spanner-wielders want to use something else, then fine, but the SI units of meter, second, second, ampere etc. and the derived quantities, like the Newton, were agreed on by the scientific community in 1960. They are defined by physicists and it isn't going to change.

        The CGS units are not SI units by the way. It may be an alternative metric unit, but SI it is not.

        1. Stoneshop Silver badge

          Which one?

          "the SI units of meter, second, second, ampere etc"

          The first second, or the second?

      5. Tom 13


        Or Celestial Goofy Shit as we called in Asto class because we never could figure out why you'd choose it as your base when the closest star is over 4 light years away. But for some reason it was and therefore the exponents were always even larger.

        1. PT


          I see we are still some way off achieving standards of spelling. Gramme? Metre? Seriously, WTF? Speak English. Once the perfidious French lose control of the last physical standard there will be no further reason to humour them.

    2. John I'm only dancing

      And also surely

      1/1000 of a litre is 1gram of pure water, you know a 1/1000 of a kilogram. Why not base all measurement on pure water, not heavy water, just normal water...

      On second thoughts, best not, some trendy "I only drink pure water' git will come along and drink it!!

  8. Nebulo


    There doesn't seem to be an official (= Register) unit of mass. Yet.

  9. AlistairJ
    Thumb Up

    Put it on eBay

    It will make a fine paperweight.

    1. Loyal Commenter Silver badge

      There is the Jub

      Although technically, that is a unit of weight, I'm pretty sure The Reg unit of mass could be defined as the mass required to produce 1 Jb of weight, under standard gravity at sea-level. (1Jb = 4.2Kg)

    2. Graham Dawson


      The most common comparisons seem to be a fully loaded 747 and a bag of cement. A london bus must surely be in there somewhere as well.

      1. Blue eyed boy
        Thumb Up

        Not forgetting Wales as a unit of area.

        If it were flattened out it would be bigger than E*****d

    3. Nigel 11

      Register unit of Mass

      Isn't the Pound (1 lb) odd enough, considered along with its siblings: grains, ounces, stones, hundredweights, tons, and you really don't want to know about its cousins. Oh, you do? Well google "Imperial Units of weight"

      The centihundredweight (or cCwt?) might be amusing: cancelling, you get exactly one weight. (1 wt.)

      In passing, why do the French use tonnes, when clearly they ought to use megagrammes?

      1. Graham Dawson

        Same reason there's a 500g metric pound

        Stubborn refusal to give something up. Sort of like me with feet, as you will hopefully see somewhere higher up. :D

    4. Geoff 25


      Or should that be paper-mass?

      1. C-N

        re: paper-mass

        As long as you use it here on Earth, it makes a decent paperweight.

    5. jonathanb Silver badge

      Re: Er

      How about the John Prescott? That is sometimes used elsewhere as a unit of mass.

  10. Lottie


    Weights and measures should always be reviewed to keep them as accurate as possible.

  11. The Indomitable Gall

    Just as well...

    It's just as well the metric system wasn't invented in England. Imagine the Daily Mail's reaction if the kilogramme in question was stored at the Royal Society's headquarters!!!!!!

  12. Rob 30

    raises more questions..

    such as why is it made from platinum and iridium, rather than say, lead or rock?

    how does it change weight? if it's in a sealed chamber it would seem there's not enough there to affect it..

  13. micheal

    would it not be easier

    to define it as a perch plus a bushell, minus a rod and add 3 gerbils to counterbalance the lot?

    mine's a 0.476 litre if you're buying!!

    1. Ian Stephenson Silver badge

      Why do you want 83.8% of a pint?

      I'll have 568ml please!

    2. The Indomitable Gall


      Wouldn't you prefer a 0.568 litre...?

    3. Mike Richards

      Why platinum and iridium

      They're pretty unreactive elements so unlikely to accumulate mass by grabbing oxygen atoms from the atmosphere. The iridium is probably there to harden the platinum.

      There is a project to calculate the kilogram as the mass of a certain number of atoms of a crystalline substance such as silicon:

      1. mspletz

        buoyancy too

        The other reason they use the platinum iridium alloy is it is also very dense. The smaller the volume, the smaller the error introduced during measuring from it's buoyancy (i.e., the amount of air it displaces). It may not seem like much, but when you're worried about fractions of a microgram, it becomes important. If you still doubt it, consider the complications of weighing (in air) the standard kilogram if it was defined as a the mass of certain volume of helium...

      2. Blue eyed boy

        But platinum is radioactive!

        Platinum contains two naturally occurring radioactive isotopes (190 and 192). OK so they have half-lives longer than the age of the universe, but their decay ought to be detectable. Wouldn't explain where the mercury has come from though.

    4. BristolBachelor Gold badge

      Weight change

      One of the contaminants that they found on it just before the official polisher retired was mercury. They wondered where the hell it came from and then realised that people were breathing it out from their fillings.

      I think I am never going to breathe in through my mouth again; mercury poisoning is not very nice!

      1. Stevie Silver badge


        Disbelief have I.

        More likely that the Mercury came from the gills of all the fish in the atmosphere.

        Mercury in good old British fillings is already bonded with silver quite tightly.

        Unless, of course, this is evidence of yet another French Innovation: Silver-free amalgam fillings.

        I've had "dangerous" amalgam fillings in my head for nearly 50 years and it hasn't harmed me.

        Major Frisnit le Boeuf en Croute (Mrs).

        P.S. Baaaaa!

    5. Stevie Silver badge


      Obviously a failed French attempt to make a Positronic Brain.

  14. James Pickett


    Sounds like a good opportunity to restore proper Imperial measurements to their rightful place. I have a pound of sausages they could use...

    OK - it’s 454g, but what the hell.

  15. Popup

    There are other options

    That's only one of several competing contenders for an updated definition.

    One idea that I tend to like is to simply count the number of atoms of a certain isotope, and define Avogadros constant at the same time. A kilogram would then simply be defined as the weight of a certain number of Carbon-12 atoms.

    1. Anonymous Coward

      Its mass, not weight

      A pound of sausages weighs one pound... on Earth.

      But a kilo is a unit of mass, not weight. A kilo of sausages is still a kilo unless you approach the speed of light...

      1. Big-nosed Pengie

        It would seem appropriate

        to define the kilo as a certain number of sausages.

        If it doesn't work you can always eat them!

        1. John I'm only dancing

          At what temperature?

          If you are talking about mass, at -273 degrees C, or ZERO kelvin, there is no mass as protons, electrons, positrons,etc, do not move.

          1. Ken Hagan Gold badge

            Re: At what temperature

            Umm, you might want to have a google for "rest mass" and for "zero-point energy".

    2. Anonymous Coward

      Had to be done

      "A kilogram would then simply be defined as the weight of a certain number of Carbon-12 atoms."

      A kilogram is a measurement of mass, not weight.

  16. Maurice Shakeshaft

    I understood the Planck constant wasn't...

    and that it varied depending upon your location in space...? I'm as thick as one though - a plank, that is - so may be feeling the sword point at my back.

    Perhaps it is adequately specific and accurate for local purposes but then again so may be the mass in Paris.

    Sound like a lot of effort for nothing dramatically important. Or have I missed the fundamental point at debate here? Is this the most important 'Standards' issue or just the one that will catch the most headlines and earn the most grants?

    1. David Gosnell

      It would seem to be constant everywhere

      However, looking into this, I see that its value is rather contentious after about 9 significant figures, which makes one wonder whether these microgramme variations in the kilogramme standard are really much to be worrying about, and whether the Planck solution is actually any more reliable.

      1. Ken Hagan Gold badge

        more reliable

        If Planck's constant is constant, then even if we don't know it to more than 9 sig fig today, any definition of the kilogram based on it would be reproducible to whatever level of experimental accuracy we are capable of in the future. It's that reproducibility that matters here. We're not trying to measure the mass of that cylinder, we're trying to compare other masses with it and hoping to get the same results as other people who are also trying to compare other masses with it.

        If Planck's constant varies, then either it varies on a cosmological timescale, which wouldn't bother us in the near future, or we've discovered some exciting new physics. I doubt any physicist would consider the latter to be a problem.

        Lastly, although I haven't looked at this particular issue, it wouldn't surprise me if there are reasons why we can be certain of the constancy of Planck's constant to rather more sig figs than we can be certain of its actual value.

  17. TeeCee Gold badge

    Cleaning the kilo.

    As I heard it, there's one elderly bloke allowed to do this. Apparently he knows how to do it without rubbing off any of the actual kilo.

    Personally I find the fact that you can currently put a serious crimp in the laws of physics using only Vim and a Brillo pad rather amusing.....

  18. Andrew Stevenson

    Wow, I thought this happened years ago

    Wow, I thought this happened years ago

  19. Rogerborg

    Bah, more short term thinking

    Back in my undergraduate days, we used to joke about it being the Planck Very-Nearly-Constant. Oh, we were a laugh-an-aeon, I can tell you.

    In all seriousness, Planck's Constant will (likely) vary over cosmological time, so we may have to come up with a new measure by the time the sun burns out, or we get flying cars, whichever comes first.

  20. Velv Silver badge

    Compared to what ?

    "But it is compared from time to time with other exact copies held by other nations, and it is known that in reality slight changes on the order of microgrammes - a billionth of a kilo - do occur"

    And how do they know it is not the "exact copies" that have changed mass ? (and clearly they can't be exact copies!)

    And how do they do the measurement ? Which "unit" do they take to the other to do the comparison, and would this "transportation" of one unit not introduce substantial risk of change (e.g., when it gets X-rayed at the airport, could the x-rays knock off a few atoms, thus changing the weight)

    1. Brian Morrison

      You use...

      ....the three-cornered-hat techniques, essentially by comparing pairs of weights and looking at the differences between each pair and then comparing those differences in a multiple simultaneous equation.

      At least, I think that's how you do it.....

    2. Tom 13

      @velv: You should never expect certainty

      when Planck is involved.

  21. AlGodet

    UK and US

    It is interesting to see that the countries behind the campaign are :

    - UK : which did not use SI until quite recently (about 20 years)

    - US : which DOES NOT use SI

    Come on guys, get back to bed ! And wake up again when you own backyard is cleaned...

    1. Chemist

      Re : UK and US →

      All the scientists do - as well as most engineers etc

      1. Apocalypse Later

        A few don't

        "All the scientists do - as well as most engineers etc"

        They don't all use metric. Britain's martian probe burned up on entry because the Brits specified something in metric and the US space boffins in charge of transporting it read the figures as whatever passes for Imperial in the US. Are those guys just engineers, or is it rocket science?

      2. Nick Ryan Silver badge

        US engineers?

        US engineers using SI? Not from experience they don't.

        UK engineers tend to use SI though, however this also varies by their age.

    2. Anonymous Coward

      @ UK & US

      I must be about 45 years younger than I thought: as a schoolboy in England in the sixties, doing sciences actually, as well as the usual maths, we definitely used the metric system. I do remember the usual mental arithmetic questions in the mid to late 1950's (how much does a dozen eggs cost at 3 farthings an egg .... Absolutely invaluable skill now). I even recall my first physics laboratory lesson, working out that one inch is 2.54 centimetres.

      Actually, I think UK was metric for scientific matters much longer than that.

      As for the US, apart from short-changing most of the world in most things, they even short-change themselves in liquid matters - took the wrong measuring bucket with them when they invaded the place, apparently.

    3. Marco van de Voort

      US interest in redefining.

      > US : which DOES NOT use SI

      The US imperial system is specified in SI base units much longer than the UK one. Stronger even, some of the so called Founding Fathers already made a case for SI (because they could get better standards info from their ally France than from the Brits that were still fumigating because of some lost tea).

      IIRC the American Imperial System is defined in SI base units since the 1870s. Like the UK, it is the plebs that can't deal with it.

  22. Havin_it

    Was all this necessary?

    I hope I have this right, but I seem to recall from school that 1g is the mass of 1cm^3 of water (I assume there's a specified temperature applicable here, but who knows what that is). I also recall the school had a rather nice heavy wooden weapon^H^H^H^H teaching aid that was a 10x10x10cm cube.

    Shirley then, all you need to do is fill the bath to the top, lob the block in and weigh the water that pours out. Platinum-iridium chamfered cylinder? Has the world gone mad? (Or just the French?)

  23. Anonymous Coward

    An appalling lack of physicists around here

    "how does it change weight?" Radioactive decay, for one.

  24. Nigel 11

    Another subtlety

    Another subtlety is whether gravitational mass (commonly known as weight) is the same as inertial mass. It's been shown to very high accuracy that the two are equivalent for everyday forms of matter. But is the inertial mass of a kilogramme of electrons the same as that of a kilogramme of protons or a kilogramme of neutrons?

    1. Chemist

      Re : "kilogramme of electrons......."

      If I had a kilo of electrons in one hand and a kilo of protons in the other - I'd be very dead I think !

      1. Ian Stephenson Silver badge

        Dont be ...



  25. Yet Another Anonymous coward Silver badge

    @UK and US

    The US has always been metric, when they had their little tantrum over the tea in Boston harbour we wouldn't let them into the houses of parliament to compare their yard against the real one.

    So the french lent them a metre ruler - but they didn't quite do the sums right which is why a US inch and a proper inch used to be slightly different - until we compromised on the international inch.

  26. DI_Wyman

    why not...

    .....just use half a 2Kg bag of sugar from Sainsburys?

  27. James Pickett


    “1 Jb of weight, under standard gravity at sea-level.”

    Have to make it just above sea-level, I think. Jubs are pretty much weightless in seawater in my experience...

    1. Red Bren

      @James Pickett or should that be Jamie?

      "Jubs are pretty much weightless in seawater in my experience"

      Have you been overdoing the HRT?

  28. Cameron Colley


    They should use a definition based upon the Hubble constant -- would be far more accurate.

    1. Chemist

      Re : Pah!

      It's accuracy is known to ~50 parts per billion which is rather better than the Hubble constant which is ~ +/- 2%


  29. Trollslayer Silver badge

    I may as well be the first to say

    "and by the middle of the decade the French official kilogramme can be retired" - at 62?

  30. Alex Walsh


    Wasn't there a bit on here about clocks running at different times if one was half way up the stairs? What is the stairs effect Plancks constant in a similar way?

    1. Chemist

      Re : height

      It's not that clocks run at different times - it's time that runs differently.

      It's affected by lots of stuff, gravity, velocity, acceleration. That's why the train is usually late

  31. Sam Liddicott

    for some reason

    "but was modified under Elizabeth the first for some reason)"

    have you found any reasons? I've heard of one supposed and mystical reason to do with the number of miles of key sites from Jerusalem and major events related to those sites.

    Should SI units have a metaphysical basis?

  32. JaitcH

    What is the significance of a "chamfered cylinder" in a standard?

    I understand the mechanical benefits of a chamfered cylinder, but what beneficial effects would they have on a static standard of weight?

    1. Stoneshop Silver badge


      If the top and bottom had straight edges, you would be more likely to chip off a few atoms when you set it down. At least, that's the reason I can think of for doing it

  33. Fluffykins Silver badge

    There's one way the French will buy it:

    Consultative Committee for Units have proposed that the kilo should instead be defined in terms of the Planck constant

    Just tell our vintneous friends that it will be referred to as the Plonk constant.

    Tres simples.

  34. Heff


    the thing I found most fascinating about the article is wondering how these fumbling fucks get paid. you want to hold a kilo of platinum (if it were pure, you're looking at around 35 grand for a hunk that big) in several nested boxes polished by some geriatric frenchman who probably has no other job, in some specially constructed little room of wonder?

    how much does this anachronistic bullshit cost us versus just defining it via non-corporeal means? hell, if you'd put the price points in and shown us how The British Taxpayer Pays for French billion-dollar paperweight, the Daily Fail woulda picked this shit up in a heartbeat.

    mines the one with the quarter of bonfire toffee. mmmn. toffee.

  35. CADmonkey

    Oi! Metric Sytem!

    Represent a third.....go on! What's that? three point three what? LOL


    1. Tonik


      1/3 kg, here you have it one third of a kilogram.

    2. M Gale

      33.33% recurring.

      Now, define Pi in fractions, please. 3 and how many whats?


  36. Sailfish

    Up Next: What to do about that pesky metre?

    "Although it was later determined that the first prototype metre bar was short by a fifth of a millimetre because of miscalculation of the flattening of the Earth, this length became the standard. The circumference of the Earth through the poles is therefore slightly more than forty million metres."


  37. Anonymous Coward


    If it was good enough in 1879, it is good enough now!

    But FAIL because mass is not a verb.

    1. Ken Hagan Gold badge

      Re: mass is not a verb

      Yeah but we know what he meant and if he'd said weighs we'd have have an army of pedants massing at the gates to the comments pages. Oh hang on, someone did, and they did.

      1. Jimbo 6

        Wouldn't they be...

        ...weighting at the gates ?

  38. AlanS

    MKS vs. CGS

    An important difference between MKS and CGS is the unit of work. To raise perhaps 80kg by 1 metre in a 1g (10 m/s2) gravity field uses 800 Joules; in CGS, that is 80 million ergs, and that's only enough for me to get out of bed in the morning!

  39. Rombizio

    It's 2010...

    Where is my flying car?

  40. PatrickE

    Used kilogram

    If they don't have any use for it - can I have it please? Make a great door stop.

  41. Eddy Ito Silver badge

    While we're at it.

    Can we just define the mole as exactly 6 x 10e23 and round off all those other nasty constants? Let's face it, does anyone really care if a mole is about 0.37% off it's old number? I thought not, daltons are still daltons and the kilogram has been defined in more absolute terms; at least until something ionizes but who cares as long as they keep their hands off our bulgarian airbags.

  42. -tim

    12 Inch pianist?

    If the French been better with their astronomy, a metric foot would be nano-light-second.

  43. Herby Silver badge

    Changing kilogram...

    Kinda like the Mel Brooks "History of the World, Part 1", where Moses comes down from the mountain and says: "Here are the 15 [drops one tablet] ooops, 10 commandments". Changing kilogram, might happen so, if it changes, will my body mass index change as well, and the government charge me more for my medical insurance if it goes the wrong way?

    As for the US being on the SI system. Yes, it has been for many years. All our units are defined in terms of metric units. Like an inch IS 2.54 cm.

    As for Troy ounces, Linux's units command yields that they are 31.1... grams. So when you see the late night ads for "gold leaf coins" that have 31 milligrams of gold on them, that is 1/1000 of a troy ounce, or about $1.34 or so, or not very much!

  44. Wibble

    State of the sun & moon?

    I've always wondered if the state of the sun and moon should be considered when weighing things to this accuracy. After all, these celestial objects are responsible for moving giga-tons of water around the planet. Just ask Canute. Oh, he drowned.

  45. Clyde

    sacré vache

    That should be sacrée vache, a vache being feminine

  46. Adam Trickett

    Troy Ounce are derived from metric units?

    I thought that all "modern" Imperial measurements were now legally defined by deriving them from an SI unit, so even though the bank may use an ounce of gold it's actually based on the Kilo anyway...!

  47. Martin H Watson

    What I've never known is...

    ...why we pronounce Cen'timetre, Mill'imetre, but some folk say kilom-etre.

  48. AndrueC Silver badge

    Prefixes to the lot of you

    I'd far rather 'they' spent money educated people about SI prefixes.

    I'm fed up with people who whine because they 'only' have a 4MB/s internet connection.

    Or people who boast because they have a 50mb/s connection.

    There's also no such thing as a 1tb disk. If there were it wouldn't store much data.

    1. Sir Runcible Spoon Silver badge


      educated != educating

      You broke the first rule of pedantry.

    2. M Gale

      One terabit? 128 gigabytes?

      I'd call that a fuckload, myself.

      Question is, how much of that data is information.

  49. mark 63 Silver badge

    A litre of water weighs 1Kg

    surely thats not a coincidence?

    so whatever defines a litre also defines the KG , not some rusty block in paris?

    unless the liter is defined from the 1 kg of water

  50. Stoneshop Silver badge

    No definition

    A liter of water (at 277K and 1*10^6Pa) is indeed 1kg, but try varying the temperature or ambient pressure a bit and you'll be sufficiently off to throw any semblance of precision out the window. And precision counts in definitions. So anything that doesn't rely on other measurements is to be preferred: [large_number of stable_atoms] is quite a bit better than [amount of fluid that goes in a container of some size at this temperature and that pressure]

    1. jonathanb Silver badge

      Re: definition

      But the main problem is that the Pascal unit to measure pressure is in part derived from the kilogram, so the kg can't be based on an amount of water at a particular pressure because then you get a circular definition.

  51. James Pickett

    Alive and well

    I was pleased to hear a recent birth announcement on the radio expressed in pounds and ounces. Metric never quite cuts it for babies, somehow.

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