>>> 1 meter/39.37 inches = 0.02540 meters/inch = 2.54 cm/inch = 25.4 mm/inch >>> >>> Exactly. >>> >> As long as exact means within a few parts per million: >> >> 1/meter/39.37 inches = 0.025400051 meters/inch ... >> >> >>> -Chuck Harris >>> >> _______________________________________________ >> time-nuts mailing list >> [email protected] >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> > Chuck > > That's a little sloppy for this list surely. > > In fact the US currently uses 2 different inches the "survey" inch (plus > yard, mile etc) which is defined by the relation > > 1 metre = 39.37 "survey" inches exactly. > > This inch is used purely for surveying purposes. > > The other inch defined by > > 1 inch = 25.4mm exactly > > is used for everything else.
My recollection when I posted the earlier letter was 24.5 mm/inch was exact by definition, and I recalled that 39.37 inches/meter was also exact... a quick calculator check to 6 figures showed that it was exact, then I tried to 9 figures, and saw that pesky little 0.000000051. > For confirmation read the appendix C of NIST Handbook 44, where these > and other units of measurement are described. > Why on earth one has to have different units all called barrels for oil, > cranberry juice, dried fruits, liquor (this one varies from state to > state) etc., defies imagination. I think the biggest push for metric is the chance to start fresh. But when metric includes piezes, and poises, and sthenes and steres and stokes... I guess it ain't all that fresh. -Chuck _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
