However, Joe, I'm suggesting constructing such a clock (although, strangely, at least one person has).
An example of the use of 24:00 would be the Catholic Church's Christmas midnight mass. As people who attend it leave their houses on December 24, it's less confusing to say that it starts at 24:00 on December 24, rather than at 00:00 on December 25. Catholics, of course, know very well the date on which they must set out to attend midnight mass. However, the same approach would apply to and be useful for less familiar midnight events. Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Joseph B. Reid Sent: Thursday, January 03, 2002 12:41 To: U.S. Metric Association Subject: [USMA:17171] RE: Celebrations in Maastricht Thanks, Bill. I don't recall mentioning 24:00, but I agree with what you wrote in USMA 17129. However, I would add that 24 lasts for only one second; 24:00:01 is not valid. Hence it would be very complicated to construct a clock that would show 24:00 >As Joe Reid (I think) has pointed out, it depends on the context. > >Although 24-hour clocks don't display 24:00, expressing midnight as 24:00 is >explicitly permitted by ISO 8601:1988 as an alternative to 00:00 -- in >emphasizing the completion of one day, for example, rather than the >beginning of the next. > >I haven't checked ISO 8601:2000, as I don't have a copy. However, Markus >Kuhn's web site (accessible from http://metric1.org/dateandtime.htm) >contains the following: > >As every day both starts and ends with midnight, the two notations 00:00 and >24:00 are available to distinguish the two midnights that can be associated >with one date. This means that the following two notations refer to exactly >the same point in time: > >1995-02-04 24:00 = 1995-02-05 00:00 > >In case an unambiguous representation of time is required, 00:00 is usually >the preferred notation for midnight and not 24:00. Digital clocks display >00:00 and not 24:00. > >Bill Potts, CMS Joseph B.Reid 17 Glebe Road West Toronto M5P 1C8 TEL. 416-486-6071
