[time-nuts] Standards for units

James Cloos cloos+febo-time-nuts at jhcloos.com
Mon Apr 2 23:29:57 EDT 2007


>>>>> "David" == David Dameron <ddameron at earthlink.net> writes:

David> (I was taught that 1 meter was 39.37 inches, to define the
David> inch, but now I see more of 1 inch = 2.54 cm, as someone just
David> referred to.)

That was the old inch.  It was changed back around 1954 or so.  They
decided they didn't want to have an SI unit looking like it was
defined in terms of a legacy unit, and so changed from 1 meter = 39.37
inches to 1 inch = .0254 meters so that the inch was defined in terms
of the meter.  

Or, as likely, from 1 meter = 3937/1200 feet to 1 foot = .3048 meters.

The old length is still used for so called survey feet in the US.

Many conversion routines -- including unix's units(1) and HP's line of
RPL calculators -- call them US feet.

-JimC
-- 
James Cloos <cloos at jhcloos.com>         OpenPGP: 1024D/ED7DAEA6



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