---------- Forwarded message ----------
Date: Fri, 29 Jun 2001 15:56:14 +0200
From: Terry Quinn <[EMAIL PROTECTED]>
To: Ian Mills <[EMAIL PROTECTED]>, Gene Mechtly <[EMAIL PROTECTED]>,
"Martin, Peter" <[EMAIL PROTECTED]>,
"Taylor, Barry N." <[EMAIL PROTECTED]>
Subject: Re: Symbols for SI Prefixes
Dear Ian
Symbols for SI prefixes.
I have recently been informed by the European Commission that the
apparent acceptance in a European Directive of the symbols D, H, and K is
now recognized as having been a simple mistake and that steps are being
taken to rectify it.
With best regards
Terry
At 12:27 28/06/2001 +0100, Ian Mills wrote:
>Dear Gene,
>
>I am sorry to have been so slow in replying to your last email. For various
>reasons it did not get an immediate reply, and then it got lost in the
>press of
>other matters that I have had to deal with.
>
>However I have little to add, in reply to your questions, to the
>information that I
>reported in my last message to you. The proposal for the alternative
>symbols D, H
>and K to be allowed in parallel with the existing symbols da, h and k was
>discussed, and the decision was taken to make no change in the current
>rules for
>prefixes. We did not actually vote because the decision was essentially
>unanimous. The reason for making no change was that the CCU is strongly
>of the
>opinion that making many small changes to the SI will lead to confusion,
>and hence
>that it is better to make no changes unless we feel the case to be
>overwhelming.
>In this case the meeting did not feel that the case was so strong. The CCU
>receives many proposals for small changes to the SI, and generally these
>are not
>accepted, even though many of them have some logical support.
>
>It is not for me to detail who spoke which way on issues of this
>kind. The members
>of the CCU are there as representatives of their supporting institutions,
>such as
>the NIST, the NPL, the IUPAP, and the IUPAC; they are not present in a
>personal
>capacity. Thus you should lobby your representative from one of these
>bodies if
>you wish to express a view.
>
>In my last message I also mentioned the problem of the two alternative
>names "SI
>units" and "units of the SI", which have been given different meanings in the
>ruling of the CCU in recent years. In this case we again considered the
>alternative of making no change, for the reasons mentioned above, but we felt
>ourselves forced to make a change for two reasons.
>First, it is a violation of the English language to attach different
>meanings to
>the phrases "SI units" and "units of the SI". That was put to us by several
>people, and it seemed a compelling reason for making a change.
>Second, it was also put to us that most ordinary folk, indeed almost all folk
>whether or not they are trained scientists, find it extraordinary to be
>told (for
>example) that the kilometre, the centimetre, and the millimetre are not SI
>units.
>It seems to violate common understanding.
>We therefore decided to make the change that I believe I described briefly
>in my
>last message, namely that one should use the phrase "coherent SI units" to
>refer to
>only the SI base units and the coherent derived units (i.e. those without
>prefixes,
>excluding the exceptional case of the kilogram). Then the phrases "SI
>units" and
>"units of the SI" may both be taken to refer to all the units with or without
>prefixes.
>
>I am sorry to disappoint you.
>
>With my best wishes, Ian Mills
>---------------------------------------------------------
>from: Ian Mills, President of the CCU
> Department of Chemistry
> University of Reading
> Reading RG6 6AD U.K.
>phone: +44 (0)118 931 8456
>fax: +44 (0)118 931 1610
>email: [EMAIL PROTECTED]
>web: http://www.chem.rdg.ac.uk//dept/staff/phys/imm.html
>
