Russell McMahon wrote: > Last I recall it was actually N times the wavelength of a certain > emisison line of a certain gas (but they keep 'improving' these things > so ... ) :-) That was the previous standard. With new more accurate atomic clocks available the meter was redefined as the distance light travels in vacuum during a specific time. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist