The original definition of the meter/metre was a certain fraction of the circumference of the earth. Today the definition is a certain number of wave lengths of the orange light given off by Krypton 86 at a particular temperature (or something like that). The modern, atandard English foot was derived by adding the lengths of the first ten grown men who entered a particular church one particular day and then dividing that sum by ten. This latter method, of course, was not arbitrary, but was completely intuitive. Bill Fairchild Franklin, TN
----- Original Message ----- From: "John Gilmore" <[email protected]> To: [email protected] Sent: Tuesday, January 7, 2014 5:03:50 PM Subject: Re: OT: SI units and precision All conceptually adequate systems of measurement are in some sense arbitrary, whether they be the Système Internationale (SI) or one that uses the furlong, troy ounce and fortnight instead. That conceded, the SI is the one used internationally, i.e., almost everywhere outside the United States (and, of course, by the scientific community within it). Our persistence in using antique English units not quite consistently instead is a dubious example of American particularism, as quaint as our obdurate persistence in using 12-hour clock time and AM and PM, the later much misused because M has been forgotten/suppressed. Moreover, "preoccupation with multiples of ten" is not at all silly. Conversion errors are very much more common in mixed-radix systems than they are in the SI. I could go on: the definition of the meter is not based upon the putative circumference of the earth, etc., etc. I am reminded of Oscar Wilde's characterization of fox hunting. John Gilmore, Ashland, MA 01721 - USA
