[tz] switches at 1883-11-18 at the same instant
Michael H Deckers
michael.h.deckers at googlemail.com
Tue Mar 20 22:12:03 UTC 2018
On 2018-03-19 22:51, Paul Eggert wrote abput my proposal to
change the switches on 1883-11-18 in the US to a single instant:
> But we have a reliable eyewitness account that New York had two noons
> that day. See the quotation from William F. Allen in the
> "northamerica" file, taken from Bartky's 1989 paper
> <http://dx.doi.org/10.2307/3105430>. So the New York switch cannot
> have been at 18:00 GMT that day, as that would have meant two
> instances of 13:00, not two instances of 12:00. Bartky writes that it
> was called the "day of two noons" because eastern parts of the new
> zones observed noon twice, which wouldn't have happened if everyone
> switched at 18:00 GMT.
> Allen also wrote that New York got its time signal from the Naval
> Observatory, not from the Allegheny Observatory. Back then, different
> observatories were competing for the time-setting business. Perhaps
> the SpaceWatchtower sources included Allegheny partisans? (It's hard
> to tell from its source list.)
> It's possible that parts of the US switched at around 12:00 local time
> while other parts switched at 18:00 GMT; but if that's the case, I'd
> like sources for which parts switched which way.
Yes, I do not know a primary source supporting my propsal,
so you are right to ignore it.
On the other hand, one cannot trust [Bartky 1989] in this
technical matter: he implies on [page 49] that the railway time
scales switching on 1883-11-18 started the new scale with
1883-11-18 + 12 h while he reproduces a primary source on [p 50]
that shows that the new scale in Louisville, KY started with
1883-11-18 + 10 h, so that no "double noon" could occur.
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