James Freysinger wrote in USMA 17873: >Duncan Bath wrote: >> >> -----Original Message----- >> From: Pat Naughtin <[EMAIL PROTECTED]> >.... >> >Is a micron a nickname for micronewtons, mirolitres, micrometres, or >> >micrograms? >> >> Good question. It answers mine! >> On second thought - does it? The micron was specific to length, was it >> not?. > > Yes, in 1948 the 9th CGPM declared, in Resolution 7, the micron's >symbol to be the lowercase Greek letter mu, but the micron existed >before then as a unit of length (not of mass, volume, or any other >quantity). I do not find in the brochure a note on when the micron was >first defined. The table accompanying the 1866 Act of Congress in the >U.S. does not include the micron (the length table ranges from >myriameter* down to millimeter) so that probably puts an early bound on >its inception. My Webster's Ninth New Collegiate Dictionary gives 1892 >as the date it was first used and interestingly it was one year later >that the Mendenhall Order was published. > >Jim >* myriameter = 10 km = 10 000 m; myria was an old metric prefix for 10 >000.
The Shorter Oxford Dictionary dates birth of the micron as 1892 Joseph B.Reid 17 Glebe Road West Toronto M5P 1C8 TEL. 416-486-6071
