I think Joe Reid has done a good job of answering your question. However, to reiterate his point, SI is the current manifestation of the metric system. Under SI, many of the older metric units have been declared obsolete (either because they have been replaced by more manageable units or because they are redundant).
Metric units, whether SI or pre-SI are those whose definition is based solely on the base units. Originally, those base units were centimeter, gram and second; subsequently, they were meter, kilogram (the only prefixed base unit), second and amp�re. With SI, the base units are meter (length), kilogram (mass), second (time), amp�re (current), kelvin (thermodynamic temperature), mole (amount of substance) and candela (luminous intensity). All other SI units are derived from those seven. 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: Wednesday, October 23, 2002 16:03 >To: U.S. Metric Association >Subject: [USMA:22908] RE: Mishmash of units at the liquor store > > >>"Metric" is understood, in today's context, to mean SI. > >>However, "modern >>metric system" indicates SI unambiguously. > >OK. Let us forget about the past and only deal with current SI and >current metric. > >> "Metric-system" is incorrect. The term is never hyphenated. > >OK. I must have put that in accidentally because it helps with web >search engines when searching for adjacent words. > > >> In general, though, metric does not necessarily mean SI. Erg, dyne, >gauss, >> oersted, curie, and so on are all metric, but they are not SI. >> >> Therefore, "non-SI" does not mean "non-metric." > >So I understand that you mean that SI is a subset of metric. Where do >you get this definition from? What makes something metric and >non-metric? >
