Quirico Filopanti (continued)
Filopanti was the first to suggest the rule used today for synchronizing clocks all over the world – the idea of time zones. After the invention of the mechanical clock, this is the most important development in the history of the measurement of time.
| Fig. 1:
Departure
of a Great Western Railway train from Paddington Station, London. (Credit: William Powell Frith, The railway station, olio su tela, 1862) |
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As all children quickly discover when learning to tell the time, there is only one "time", which passes in a uniform way and which can be divided into equal parts. Until the beginning of the 18th century this "time" was local time, regulated by the apparent movement of the Sun and changing in accordance with variations in longitude. But with the coming of transcontinental trains, ocean-going vessels and the telegraph, this "time" fell into confusion. Between two cities 500 kilometres apart, the "time" difference in measuring mid-day, for example, is about eight minutes. Since a train travelled this distance in less than two hours, which time were they to use - the place of departure's time or the place of arrival's time? And which time should appear in the train timetable?
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They therefore needed to rethink the measurement of time. They needed to invent a time which differed slightly from local time or which had a relatively simple relationship with it. It also had to be a system that was coordinated on a worldwide level and that allowed people to work out easily the time in New York or Moscow if they knew, for example, what time it was in Bologna. | |
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Fig. 2:
Map used
in the book "A new Astronomy" by David P. Todd, probably published in 1898,
to show the different times round the world with the use of time zones. (Credit: Biblioteca 'Guido Horn d'Arturo' del Dipartimento di Astronomia dell'Università degli Studi di Bologna) |
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