Date: Sat, 07 Apr 2001 22:40:32 -0700
From: "Alan S." <as173 AT cornell DOT edu>
Subject: Re: [off-topic] shutting down
To: opendos AT delorie DOT com
Message-id: <3ACFF9D0.681E32CF@cornell.edu>
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References: <200104072210 DOT SAA14388 AT delorie DOT com>
Reply-To: opendos AT delorie DOT com

However, IIRC, there are two very slightly different 'inches', viz.:

The 'Historical' Imperial Inch equal to 2.539998... cm
and the SI Inch which is an (SI) Special Name for [exactly] 2.54 cm

You have to be a true pedant to distinguish between the two -- they
differ by only 0.000 078 740 219 480 487 779 911 637 73 % after all. 
But the resizing (enlargement!) of the inch resulted in some
simplification in conversions especially in the pre calculator and pre
PC days.

[ For that matter, the litre was resized from 1,000.028 cubic cm to be a
Special Name for (exactly) 1,000 cubic cm in 1964. ]

Alan S.
4-7-2001




rgrunsk AT attglobal DOT net wrote:
> 
> In <2 DOT 07b7 DOT V7YB DOT GBFYZF AT belous DOT munic DOT msk DOT su>, on 04/08/01
>    at 01:42 AM, "Arkady V.Belousov" <ark AT belous DOT munic DOT msk DOT su> said:
> 
> >     In 1975 Congress of USA decise to accept SI metric system in the
> >10 years period, but up to now there used non-metric units like `inch',
> >`foot', `lb', `gallon', etc. More worser, American units differes from
> >English: English gallon=4.54 litre, American gallon=3.78 litre. Same
> >for most other units, including inch.
> 
> Uh No!
> 
> There is a US and Imperial system of measure for volume (Ounce, gallon
> etc) but the units of linear measure and all others are the same. There
> is *NO* such thing as a US Inch vs an Imperial Inch. You may be thinking
> of the statute mile and the nautical mile (knot) which are two different
> measures.
> 
> Most Commonwealth countries have now gone to SI units but the Imperial
> system is still legal and used. In Canada, lumber measurements are still
> given in inches.