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... Gianluigi Parmeggiani

Osservatorio Astronomico di Bologna

The origin of time zones.

In the past every Country had its own time, founded on the apparent movement of the sun. It was measured with the solar quadrant or the sundial; when the sun passed on the local meridian it was midday. Unfortunately the sun is not an exact watch because its apparent movement along the ecliptic is not regular and the duration of the day considered as the interval between two successive passages of the sun on the meridian is variable. These differences were probably unknown to the ancient peoples that did not have precise measure instruments but they were well known from 1657 onwards with the discovery of the isocronism in pendulum oscillation and its application to watches.

The Paris watchmakers had adopted the motto: "solis mendaces arguit horas " in order to convince their customers of the quality of their watches that indicated a time different from that of the sun.

In order to obviate to this inconvenient a fictitious Sun was introduced, that could move with regularity. In this way it is possible to define an average day, constant throughout the year, and an average time different from the real time.

The different between the two middays (real and average) is about 16 minutes more and 14 minutes less (such extremes happen only twice a year); usually the difference is less than 5 minutes (about 200 days) and in four days the two middays coincide.

The first city to use the average time was Geneva in 1780 with the stoke of the big bell of the cathedral to announce midday, obviously average.

London introduce the average time in 1792, Berlin in 1810 and Paris in 1816.

In Paris the Prefect required from the Bureau des longitudes to reassure the people that were afraid that the new time could produce abuses in calculating the working hours (in fact the average midday divided the interval between sun set and sunrise in two unequal parts). In Italy the average time was adopted in Turin in 1852, in Bologna in 1858 and in Milan in 1860.

In Rome the average time was introduced in 1855 unofficially (without any government decree ) as a consequence of the development of railways and telegraph.

The drivers of the mail coaches regulated their watches every morning at departures and then informed the sexton and the postmen.

All the countries on the same meridian have at the same moment the same local time (average or real), but, at the same moment the local time is different from country to country, when these are not on the same meridian. Their local times are different according to a constant quantity which is equal to the difference in longitude between the two places (for any west longitude degree the local midday is 4 minutes later).

It is difficult to remember how quickly local times vary with longitude: for instance , at our latitude the local time difference is 1 minute for only 20 Km of east-west distance.

The discordance of local times had no influence inside a local community, but it started creating problems when people began to move more easily between different towns and provinces due to the development of the railways.

In the old times only in travels of many days duration, one could go over a one hour longitude difference and in normal commercial relations nobody was disturbed by a difference in time of less than an hour.

But the railways system and the telegraph obliged to take into account minutes and their fractions. It was necessary to re-think the time system, especially in the railways that had to work regularly and safely. At the beginning the railways connections were isolated and their timing was based on the main city from which the connection started.

As the railways system was becoming more complex, there were as many railway times as there were main cities and in the intermediate stations there was the passage from one railway time to another.

According to an idea of an astronomer John Herschel (in 1828), it was proposed a regional or even national unification of the various railway times, with a unique railway time (generally that of the capital or a better suited city).

Such unification was effected for the first time in Great Britain in 1848 ( Greenwich time for England, and Scotland and Dublin time for Ireland) and these two times were also used in the public life.

It was common in England , up to the beginning of XX century to call railway time the Greenwich time.

In Italy in 1866 there were 6 railway times (Torino, Verona, Firenze, Roma, Napoli, Palermo). On that year it was decided to unify them, adopting the average time of Rome (even if this city was not yet part of the kingdom). On the 12th December 1866, on the starting of the winter time table, it took effect in the railways, the post office and the telegraph, not only for the internal service but also for the public.

Moreover, without any particular law, but on a free initiative of the main Italian cities and as a consequence of the practical advantages of tying the railway time to the city time, and also for patriotic reasons ( Rome was not part of kingdom) it was decided to use the Rome time in public and private life producing thus a national time.

Milano set the public watches on the Rome time on the same day (12th December 1866), Torino and Bologna on the 1st January 1867, Venezia the 1st May 1880 and the last city was Cagliari in 1886.

A national time was previously adopted in Great Britain, as we said before, and in Sweden in 1879 look an exceptional decision in not adopting, the Stockholm time, but the Greenwich time.

France introduced the national time only the 14th March 1891, using the Paris time, with the quaint exception of the station internal watches that were 5 minutes late, in order to hurry the travellers.

The transition from local to railway and then national time resulted in making the time measuring uniform inside a country, but did not solve the problem outside the countries border.

The old Italian railway time table had a 47 minutes difference with the French time, a 20 minutes difference with the Swiss and a 10 minutes difference with the Austro-Hungarian time.

In longer travels everything became even more complicated: from Rome to Petersburg there were 7 different time and 12 from Paris to Costantinople; the Prussian times were as numerous as the stations ....

So on an international basis the difficulties were the same of the various local times inside a country: these had been abolished in favour of railway or national times and the problem now was whether it could not be wire to forego national times in favour of a world timing.

The solution was far from simple: abandoning national times could create political problems, and moreover the unification could not use too radical changes because life was still regulated by the sun and it was not possible to impose time that differed too much from the real ones.

A possible radical reform was the absolute universal time as proposed by Theodor von Oppolzer (1841-1886, Director of the Astronomical Observatory of Wien ) that simply extended to the whole world and for every purpose the Greenwich or any of the meridian time.

All over the world the watches would have had the same hours.

The legal day would have started all over at midnight Greenwich time, but in that case in would have been 7 p.m. in New York..

The words yesterday, today and tomorrow would have last any meaning and a great confusion would have started .....

Quirico Filopanti , pseudonym of Giuseppe Barilli, (1812-1894), a professor and political man of Bologna in 1859 suggested in his book " Miranda" a genial solution.

He proposed to divide the earth in 24 longitudinal zones along the meridians that differ from one another of one hour, with exact coincidence of minutes and seconds. The first time zone was centred on the Rome meridian and included Italy, Germany, Sweden and a part of Africa. If here it was 6 a.m. in the second going westward it would have been 7, and so on.

Filopanti also introduced a universal time to be used in astronomy and in telegraph system. To give people the knowledge of the universal and the local time the watches would have had two faces one with the letter U for the universal time, and one with the letter L for the local time, while the minutes would have been the same.

Filopanti wrote that " ..when a punctual watch at average, universal or local time, will strike an hour, the watches all over the world will strike at the same moment the same or another full hour".

Filopanti's proposal was quite practical, though its inspiration was ethical or religious.

As the earth is divided longitudinally in 360 degrees, by dividing the earth surface in 24 zones, each zone is contained between two meridians separated by 15 degrees and each zone has the time of its middle meridian separated by 7 and a half degrees from the border meridians.

With this system the unification of time measuring is reached. In fact all the States included in the same time zone, have the same time, the difference between two limitrophe time zones is exactly one hour and the various times are easily comparable.

And finally, this unification is reached without going too far from real time because in each State (or part of it) of the same time zone the difference between the real and the local time is never over half an hour.

Why then Filopanti is rarely remembered when talking about time zones ?

Probably because his proposal was too much in advance of his times (only Great Britain had a national time in 1859 and the other states still had local times), or against the spirit of the times (from 1872 to the end of the century, the scientific debate was about the absolute universal time). But the main reason probably is that in his times there were no strong economic powers like great railways or telegraph companies that would have been more interested in any system to regulated time.

In order to understand this point let us consider the United States .

In view of its great longitudinal dimension a common railway or national time was impossible: as a consequence each railways company had developed its own time table.

At the beginning of 1870 there were about 50 of them and each city had its own local time and as many railway times as lines it served....

Charles F. Dowd (1825- 1904), rector of a women college at Saratoga , N.Y. ,proposed in 1870 a System of National Time for railroads based on longitude.

The Washington time would have been the standard time and in order to homologue the railway to the local times, at every multiple of fifteen degrees from Washington ( corresponding to one hour )there would be a reduction of one hour, thus dividing the United States in four zones. Dowd presented his project first to a convention of railway superintendents then in a booklet, which contained a description of scientific principles on which the proposal was based and an example of time table for all the railroads.

The booklet has a large diffusion but also discussion on the opportunity to use the Washington meridian, which Dowd himself substituted with the Greenwich meridian, that the United States were already using since 1850 for maritime purposes.

On Dowd's grave an inscription in bronze reads " In solving the problem of standard time he proved himself a world benefactor".

Unbelievably Dowd's contribution is almost unknown not only in Europe but even in the States.

One of his contemporaneous was Sir Stanford Fleming (1827-1915), chief engineer of Canadian railways who is generally considered the inventor of time zones.

There is no information of his being interested on the problem of time before 1876, when his work " Terrestrial time " was privately published and then re-written, amplified and published in 1878.

This work proposed that all the watches in the world should indicate at the same moment the same time that Fleming proposed to call Uniform Time or Terrestrial Time .

If his system had been adopted, the local time would have been used for everyday life and, when it became necessary to have the exact time, terrestrial time should have been used. This system, even if imposed by law, would have created the greatest confusion, especially in the states far from the initial meridian. He too proposed watches with a double system of hands to show the two times.

The acceptance of time zone system came in 1879 when, in a conference he proposed the extension of the Dowd system to the whole world. Fleming proposed the creation of 24 standard times which should have been different from the initial meridian by a whole multiples.

Fleming had a large part in preparing the International Meridian Conference organised in Washington by President Chester A. Arthur to discuss the choice of the initial meridian (zero longitude ) and the creation of an international time for railways, telegraph and mail.

The same problem had been discussed at the Geodetic Conference in Rome in 1883, but with no final agreement.

The reason for unification was mainly scientific, as the lack of common time produced "loss of time to those who in astronomy , geography and geology are bound to extend their research in far way places ".

In the final resolutions " the congress proposed to adopt as first meridian the one that passes through the centre of the instrument of the Greenwich Observatory..... the congress proposed also the adoption of an universal day , which could be used where ever it may be consider useful, without proposing at the same time the elimination of local times or any other times now in use. Giovanni Celoria, then second astronomer at the Brera Observatory, commenting the decision of the Congress wrote that " from a practical point of view and in everydaylife the universal time has a minimum value. It would be ridiculous that the inhabitants of San Francisco, for instance, should count midday at about four in the morning of their local time .......obviously the life and business of the inhabitants of a given region cannot be regulated on any other time than the local, or on a time very little different from theirs, and having the simplest relation with the universal time . The United States have solved the problem in a very good way...... The Country was divided in four sections governed respectively by the time of the meridians at 75,90,105 and 120 degrees West of the Greenwich meridian.......they all differ from the Universal time of a full number of hours, and passing in the railways time tables and the telegraph from one to the other time it is sufficient to change the hour, leaving unchanged the minutes and this simple and quick calculation cannot produce mistakes and confusion.......In Europe the various Nations having their territories generally not so wide in longitude , regulate their time tables on the time of one of the national meridians. The only reform useful from an international point of view should be to choose national time differing from one another and from the Universal Time of a full number of hours making thus easy and quick the passage from one to another. But in almost all Europe this reform and the Universal Time is not taken in consideration ".

Filopanti had arrived at the same conclusion 25 years before !

However in the United States and in Canada the standard time became effective thanks to a decision of the American Railway Association at midday on the 18th November 1883 and it was quickly extended to all everyday uses. The great number of railway time tables and the impracticability of the absolute universal time for practical purposes had been fundamental.

It was also essential the intervention of W.F. Allen secretary of the general time convention , that was the organisation superintending time tables and safety of the railroads : he proved that the idea of the Standard Time corresponded to the requirements of the railroads (in fact, the number of railways times passed from 56 to 4).

There were not many oppositions but some maintained that the local time was God's time, some others did not like the zone in which they had been inserted and continued to use the old time system. That day in New York two middays were stroked, one with the local time and the other with the standard time.

The extension of the time zones all over the world was not immediate. The doubts were mainly due to the fear to loose the national time, to confuse the times of the various zones and to have not clearly defined borders of the zones, but in the end the practical advantages compared to the Universal Time were decisive.

In Europe the main supporter of the new system was the German Ernst von Hesse - Wartegg in his book "Die Einhetszeit nach Stundenzonen".

But what really counted was the opinion of Marshall Moltke who wanted it adopted by Germany because the anarchy of the railway times could mean difficulties and delays in mobilising the German Army.

In Italy the system was adopted on the 10 August 1893 by a Royal Decree (the meridian that gives the time in the zone in which Italy is included , the second one, passes through the Etna). During the night of the 31 October the watches of the railways and the government administrations were put forwards 10 minutes, this being the difference between the Rome time and that of Central Europe and in this way our country realised in its best part the change of time that a very intelligent Italian Q. Filopanti had first imagined since 1859.

In 1897 practically all European Countries had adopted the Time Zone System with the only exception of France. Only with a 1911 law this country adopted the Greenwich time declaring however that it was in fact the Paris time delayed 9 minutes and 21 seconds.

 

Translation : Cristina Palici di Suni.