Joseph B. Reid >Terry Simpson wrote in USMA 22953: >>I read: >>"the International System of Units (SI), which is the modern >>form of the metric system." >> >>and I conclude: >>1. SI unit = unit of the 'modern form of the metric system' >>(we appear to agree about this). >> >>2. Non-SI unit = not a unit of the 'modern form of the >>metric system' (we do not appear to agree about this). >> >>Am I wrong in my second conclusion? > >Yo9u are wrong See Tables 6, 7, and 8 of the "The >International System of Units". >Table 6. Non-SI units accepted for use with the Intenational >System >Table 7. Non-SIunits accepted for use with the International >system, whose values in SI units are obtained experimentally. >Table 8. Other non-SI units currently accepted for use with the >International System.. > >It is the units of Tables 9 and 9 that should be avoided, although >many people still use them. > Table 9. Derived CGS units with special names > Table 10. Examples of other non-SI units
Thank you for your reply. I see that table 6, 7 and 8 are non-SI units that are 'accepted for use'. I see also that tables 9 and 10 are non-SI units that are 'not encouraged'. We agree about all these being 'non-SI'. The problem only comes into play when we start using the term 'metric system' which is not mentioned in these tables. I need to see a currently valid definition of 'metric system'. If found the phrase 'metric system' here: "the International System of Units (SI), which is the modern form of the metric system." I conclude: 1. SI unit = unit of the 'modern form of the metric system' (we appear to agree about this). 2. Non-SI unit = not a unit of the 'modern form of the metric system' (we do not appear to agree about this). When you say: "You are wrong" I take it to mean that either the definition or one of my conclusions is wrong but I do not know which it is, can you tell me which? I appreciate you taking time to clarify this. I would be happy if anybody else in the list could clarify this for me. -- Terry Simpson Human Factors Consultant [EMAIL PROTECTED] www.connected-systems.com Phone: +44 7850 511794
