Alois Treindl wrote:>
All Swiss timezone history sources in astrology books and data collections maintain that all of Switzerland was legally on Berne time, starting 1851, until the introduction of CET on 1 June 1894.
That disagrees with Shanks and with the tz data, but I suppose we should trust Swiss astrology books over Shanks for Swiss data. Is there a specific astrology-book source for that? Also, exactly when in 1851 was the transition? And what exactly was Berne time's offset from GMT? (Shanks gives two values, which disagree!) Do these Swiss astrology books give sources? For example, if there was an 1851 Swiss federal law, what law was it? Given the information I've seen already, I think it unlikely that all of Switzerland (save Geneva) switched at the same time. I think it more likely that the Neuchatel Observatory established a standard (perhaps with some legal backing) and that various localities adopted the standard one by one.
There may be anecdotal evidence that some church clocks handled it differently
There sure is. Here's another. On May 15, 1905, Albert Einstein moved to the edge of Bern's unified time zone. A neighboring clock tower in Muri kept a different time -- thus helping inspire Einstein to the special theory of relativity. Yes, this is just anecdotal evidence and yes, this was after 1894 so the Muri clock was likely nonstandard, but the point is that circa-1900 civil Swiss timekeeping was not as uniform as modern observers might naively imagine. And the Swiss were the best timekeepers of the day....
My source at hand: Gabriel, Traite de l'heure dans le monde, edition 1991.
Ah, so Gabriel agrees with Shanks for Vaduz. Does Gabriel give sources? If Gabriel was compiled the same way that Shanks was and doesn't give sources, then I'm afraid I wouldn't trust Gabriel much either, as most likely Gabriel is just guessing too. But if there are sources that would be another matter. My source for Einstein: Galison P. Einstein's clocks: the place of time. Critical Inquiry 2000;26(2:)355-89 http://www.jstor.org/stable/1344127