Stan, More simply; A "tonne" is a "metric ton" is 1 000 kg in coherent SI. The Mg has never been widely used and is not coherent or appropriate for masses of 1 000 kg and more. I object to promotion of the Mg on grounds of incoherence with the SI unit of mass, the kilogram.
Gene. ---- Original message ---- >Date: Mon, 23 Jun 2008 10:56:05 -0400 >From: "Stan Jakuba" <[EMAIL PROTECTED]> >Subject: [USMA:41200] tonne >To: "U.S. Metric Association" <[email protected]> > > A copy of a letter to Editor. > > > I liked the latest issue of your newsletter very > much, particularly the CO2 disposal analysis. It was > a news to me. > > Now a negative, the "tonne" issue. Please do not > introduce a redundant (and non SI) unit into The > Energy Advocate. > > You must know about the possibility for confusion > with the tonne. There is a whole bunch of tons > already, such as tun, tann, tuna, long t., short t., > metric t.,. boiler t., etc. worldwide. Some mean > mass, others force, and most both/either. You know > that most people have no understanding what all > those "t." really mean, and will guess the "tonne" - > an obvious chance for error. > > As you know, there is simply the Mg (as there are > mg, kg, Gg, etc.) for any mass, and their meaning is > undisputed. You can always use 1000 kg if 1 Mg is > too "foreign" for you. (I give preference to > "foreign" but specific over a "used" but a matter of > interpretation.) You also know, that, aside from the > two, there is the long established "metric ton." It, > like the other "t,s", requires a qualification such > as "of mass" (massic) or "of force." In any case, > these three "units" are more than enough - why a > fourth one? > > Please, apply the KISS principle and stick > with SI. Its usage will spread quicker without > tonnes. You will agree that the general population > will catch on anything if they see it repeated > enough times. Anybody can and will be comfortable > with Mg, or kN, or kW if all the "t." nicknames > disappear. I do not need to tell you that SI is the > ultimate goal and these silly "t" nicknames, even > those approved by BIPM, are only making > the simplicity of SI less obvious and fuel > anti-metric sentiments in the US. > > Also, I should not need to point out that the E. A. > is read outside the English speaking word - how is > "tonne" in Chinese?, Arabic?, Portuguese? - what is > its international symbol? > > Let's keep the tonne where it had been - in France - > and do not support its spread. > > All the best, > Stan Jakuba
