Marcus, in USMA 19409, indicates that he still does not believe that the latest definition of the metre involves the second. I can only refer him to the metric bible, page 116, Resolution 1 of the 17th CGPM, 1983 which stated: "The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second."
>Possible, of course. But it would help foster better understanding if you >present how I was supposed to have understood that message of yours... >;-) > >Thanks in advance for your willingness to clarify that, if you'd be so kind. > >Marcus > >On Wed, 10 Apr 2002 16:47:28 > Joseph B. Reid wrote: >>I am afraid Ma Be in USMA 19387 completely misunderstood what I wrote in >>USMA 19374. >> >>> Joseph B. Reid wrote: >>>... >>>>Appendix 1 of the metric bible states that the CPGM of 1975 redommended a >>>>value for the speed of light. The second is the most accurately defined >>>>unit that we have. It is axiomatic that >>>> c = speed of light = lamda X frequency. >>>>The frequency of a laser can be determined, and by the equation, so can its >>>>wavelength. This gives a standard of length that is more accurate than the >>>>previous metal bars. It could be stated that it as based on the wavelength >>>>of a radiation of a specified frequency, or as the path travelled by light >>>>in a specified time interval. The CPGM decided in favor of the latter form >>>>of the statement. >>>>... >>>Very good, Joe. Thanks. Which goes to show that one CAN define the metre >>>without resorting to the "crutch" of the second after all. Again, it goes >>>to show how much we may still have to do and work in terms of the >>>*conceptual* aspect of defining a system of units. >>> >>>Marcus Joseph B.Reid 17 Glebe Road West Toronto M5P 1C8 Tel. 416 486-6071
