Terry: I'm not sure why you keep inserting the word "form."
SI is the modern metric system. We often express it as "modern metric system (SI)." Mks and cgs are older metric systems. I think we should regard "system" as being the important word. Each of the three systems is made up of units that were considered coherent and useful at the time. The modern metric system (SI) has rid itself of anomalous, inappropriate, redundant, hard-to-manage and hard-to-justify units. Although it's vastly better and more clearly coherent than the older systems, it is, of course, still a work in progress -- hence the regular CGPM meetings. Those older cgs and mks units that are not included in SI are still metric. They are not units of the modern metric system (SI), but they are metric, nonetheless. All units, metric or not, that are not part of SI can legitimately be referred to as non-SI. Thus, a peck (which is non-metric) is non-SI. However, as peck (along with thousands of other units) has never been considered useful by the "metric community," it's only ever mentioned in the context of conversion tables (such as those provided in the NIST SP 811 document). John Schweisthal's example of the gauss (non-SI) and the tesla (SI) quite amply illustrates how non-SI units can be quite thoroughly metric -- just not part of the modern metric system (SI). Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator] >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:owner-usma@;colostate.edu]On >Behalf Of [EMAIL PROTECTED] >Sent: Sunday, October 27, 2002 09:00 >To: U.S. Metric Association >Subject: [USMA:22961] Re: 'metric' versus 'SI' > > >kilopascal wrote: >>Here is an example: > >Thanks but I am not trying to establish what was valid in the past. My >clients in engineering companies are not required to comply with out of >date definitions. I am trying to establish what is currently valid today >so that I can give correct advice. > > >Does the statement: >"...the International System of Units (SI), which is the modern form of >the metric system." > >mean that: > >[modern form of the metric system] = [SI]? > >-- >Terry Simpson >Human Factors Consultant >[EMAIL PROTECTED] >www.connected-systems.com >Phone: +44 7850 511794 > >
