----- Doorgestuurd bericht van "Joseph B. Fox" <[EMAIL PROTECTED]> -----
Datum:Thu, 30 Aug 2001 14:22:45 +0100
Van:"Joseph B. Fox" <[EMAIL PROTECTED]>
Antwoord aan:"Joseph B. Fox" <[EMAIL PROTECTED]>
OnderwerpRe: Questions about measurement standards
Aan:Austin Spreadbury <[EMAIL PROTECTED]>, mail <[EMAIL PROTECTED]>,
han maenen <[EMAIL PROTECTED]>
Austin,
Thank you for clarifying the exact curent definition of the metre. But
in
doing so, you make my point for me - as technology advances, so the way
units are defined changes. The metre was once defined as the distance
between two marks on a bar in S�vres. The present definition will chnge
when a better time standard is established - which I believe is about to
happen.
----------
>From: Austin Spreadbury <[EMAIL PROTECTED]>
>To: "'Joseph B. Fox'" <[EMAIL PROTECTED]>, mail
<[EMAIL PROTECTED]>,
Han Maenen <[EMAIL PROTECTED]>
>Cc: [EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED],
[EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED]
>Subject: RE: Questions about measurement standards
>Date: Aug 30, 2001, 13:17
>
>I think it's wrong to say that metric measurements are defined in terms
of
>imperial ones. IMHO it's quite clearly the other way around: when
(for
>example) the inch was standardized, it was fixed at EXACTLY 25.4mm,
>splitting the difference between the former values of the UK and US
>definitions. The inch changed, not the metre, so the direction of
>dependency is quite clear.
>
>For the record, the metre is in fact now (since 1983) defined as "the
length
>of the path travelled by light in vacuum during a time interval of
>1/299,792,458 of a second", with the second being defined in terms of
some
>measurable atomic constant.
>
>Austin.
>
>-----Original Message-----
>From: Joseph B. Fox [mailto:[EMAIL PROTECTED]]
>Sent: 30 August 2001 12:57
>To: mail; Han Maenen
>Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED];
>[EMAIL PROTECTED]; [EMAIL PROTECTED];
>[EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED];
>[EMAIL PROTECTED]; [EMAIL PROTECTED]
>Subject: Re: Questions about measurement standards
>
>
>To take the first point last: recipes should be in imperial throughout
(at
>least in this country). The fact that water pressure of 9 bar was
>reccommended demonstrates that the writer had no real knowledge of the
>metric system - 9 bar is more than twice the pressure at which water
comes
>into our homes. Should have stuck with psi!
>
>As for imperial units being defined in metric terms, you could just as
well
>say that metric units are defined in imperial terms. Of course there
must
>be one and one only set of conversions - but bear in mind that the
metre is
>now defined in terms of so many wavelengths of a particualr kind of
light.
>
>But our Dutch correspondent is on firmer ground when it comes to using
>metric units to rip off the customer. The fault here lies with the
>retalier. (Same principle as "guns don't kill people - people do",
which
>sentiment I hope our new friend will thoroughly endorse.)
----- Einde doorgestuurd bericht -----
