Brian, My reading of Pat's statement is than since 1959, the inch and the pound are *defined* as exact multiples of the meter and the kilogram respectively, two of the SI *Base Units*. The millimeter and the gram are both *submultiples* of their respective coherent SI *Base Units* and are *not* units themselves independent of their respective coherent SI units the meter and the kilogram.
I object to designating SI submultiples and multiples such as the mm, cm, km, mg, and g, etc. as "units"; implying that they exist independent of their origins in coherent SI units. Call all prefixed units "multiples" (to include fractional multiples, i.e. "submultiples) but do not call them units. I am aware that the CIPM has opened the door to confusion by authorizing multiples to be called units, but I oppose this malpractice in, at least, well-disciplined discussions. One can argue, as I believe Pat does, that the inch and the pound are merely non-decimal submultiples of the meter and the kilogram. ---- Original message ---- >Date: Sat, 24 Jan 2009 20:51:47 +1100 >From: Pat Naughtin <[email protected]> >Subject: [USMA:42422] Re: A thin veneer of dishonesty >To: "U.S. Metric Association" <[email protected]> >Cc: "U.S. Metric Association" <[email protected]> > > On 2009/01/23, at 11:36 AM, Brian J White wrote: > > Not sure I truly understand what you're meaning > with this statement Pat....expand? > > At 14:01 2009-01-22, Pat Naughtin wrote: > > 8 Last, but not least, almost all length > measuring is done using the metric inch (of > exactly 25.4 millimetres), the metric foot (of > exactly 304.8 millimetres) and the metric mile > (of exactly 1609.344 metres). Meanwhile, almost > all mass measurements are carried out using the > metric pound (of exactly 453.5924 grams). > > Dear Brian, >... > 1959 > > In response to problems that arise because of a > range of slightly different inches being used, > several nations (Australia, Canada, New Zealand, > South Africa, the UK, and the USA) agreed to common > standards for the inch and the pound by defining > both of these in terms of international metric > standards (except that the USA still uses one of > their old definitions for the USA Survey foot that > makes the survey inch, at 25.400 051 millimetres, a > little larger than the international inch). The > agreed inch was made exactly equal to 25.4 > millimetres and 1 pound was made exactly equal to > 453.592 37 grams. > > The result of this agreement is that since 1959 all > of the citizens of all of these nations, Australia, > Canada, New Zealand, South Africa, the UK, and the > USA, now use a metric inch and a metric pound every > time they measure in inches or pounds. Many people > don't know that they are using the metric system > when they order a 2" x 4" or use a piece of paper > that's 8 1/2 inches by 11 inches. > > Cheers, > > Pat Naughtin > PO Box 305 Belmont 3216, > Geelong, Australia > Phone: 61 3 5241 2008 >
