The best reference for the introduction of mean solar time, and indeed for things such as railway time, local times, daylight savings time, etc. is a 2-volume work by Doris Chase Doane. I'm quite positive about her name, but don't remember the title of the work itself; she is the authority used -- hold your breath folks -- by professional astrologers, who of course need to know what variety of time they're delaing with for any given nativity. The book is not that rare, possibly reprinted, it wouldn't surprise me, and can be found or ordered thru serious astrology supply houses. Vol. I covers the United States, Vol. II the rest of the world. That is not exactly chauvinism, BTW: due to our autonomous states, early railways over large distances in longitude, etc. the history of time zones in the US is unusually complicated.
Bill Thayer LacusCurtius http://www.ukans.edu/history/index/europe/ancient_rome/E/Roman
