[Boatanchors] Fw: Re: SI units and the rest

[CLIVE COLLINS]

--- On Wed, 17/11/10, CLIVE COLLINS <dartaviation at btopenworld.com> wrote:

> From: CLIVE COLLINS <dartaviation at btopenworld.com>
> Subject: Re: [Boatanchors] SI units and the rest
> 
> Date: Wednesday, 17 November, 2010, 1:01
> Greetings from the home of the
> Imperial system, God bless it!
> The original metre (note the spelling)was said to be one
> ten millionth of the distance between the North Pole and the
> equator. However the longitude was not given a reference for
> the measurement by the French and didnt take into account
> geographical terrain variations so today we settle for an
> electronic version. By the way, for those who might be
> interested and visiting London, the Britsh Standard foot and
> yard are made of bronze and are located in Trafalgar square
> on the South Africa House side of the plaza.
> Those are the public versions including the standard
> "chain" (twenty two yards) that is laid out on the ground.
> The reference measures are kept at the British Standards
> Institution in very closely controlled conditions.
> Regards
> Clive GW3WEQ North Wales Coast UK
> 
> --- On Wed, 17/11/10, mikea <mikea at mikea.ath.cx>
> wrote:
> 
> > From: mikea <mikea at mikea.ath.cx>
> > Subject: Re: [Boatanchors] SI units and the rest
> > To: boatanchors at mailman.qth.net
> > Date: Wednesday, 17 November, 2010, 0:33
> > On Tue, Nov 16, 2010 at 07:21:30PM
> > -0500, WA5CAB at cs.com
> > wrote:
> > > I'm curious as to why it isn't 1/(3*10^8).  
> > > 
> > > In a message dated 11/16/2010 11:39:45 AM
> Central
> > Standard Time, 
> > > w7qho at aol.com
> > writes: 
> > > > The original definition of a METER  was
> > based on a measured standard  
> > > > bar.  The standard was redefined in 1983
> as
> > the distance traveled by  
> > > > light in a vacuum during a time interval of
> > 1/299,792,458 of a  
> > > > second,   The standard kilogram is
> > a a cylindrically shaped platinum- 
> > > > iridium slug and is the only SI unit still
> > defined by an artifact  
> > > > rather than a fundamental physical property
> that
> > can be reproduced in  
> > > > different laboratories.
> > > > 
> > > > Dennis D. W7QHO
> > > > Glendale, CA
> > 
> > The second was deemed to be a more fundamental unit,
> since
> > it could be
> > defined directly from a quantum transition, and so
> the
> > meter became a
> > derivative unit defined in terms of the second. 
> > 
> > -- 
> > Mike Andrews, W5EGO
> > mikea at mikea.ath.cx
> > Tired old sysadmin 
> >
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