[USMA:10192] Re: Prefixes for Mass

[Gene Mechtly]

On Sun, 31 Dec 2000, Duncan Bath wrote:
> ... the Mg IS true SI;
> ...
Duncan,

        The BIPM does not define "true SI".  What is your definition?
Do you mean "anything approved for use by the BIPM"?

        The BIPM does define the (one and only one) "SI Unit" of mass as
the kilogram.
        The gram is an exactly defined submultiple of the kilogram, and
is certainly a part of SI, but the gram itself is not an "SI Unit" under 
the precise BIPM definition of the term "SI Unit".
Gene.