Meridians and Paris Time

Did you know that for a while, official Paris time was 9 minutes and 21 seconds ahead of Greenwich Mean Time (GMT)? Let me tell you how that happened.

First of all, I assume you know a meridian is a line that runs from the North Pole to the South Pole. It is used to indicate the longitude of a location.

The Royal Observatory, Greenwich

The Royal Observatory, Greenwich (a town just outside London), is the reference point for both the Prime Meridian, putting Greenwich at 0° longitude, and Greenwich Mean Time. Both these references were progressively adopted around the world over the second half of the 19th century, some international conferences helping the process along.

The Prime Meridian at the Royal Observatory, Greenwich

Paris is in the GMT+1 time zone and at a longitude of ~2°20’E. New York is in the GMT-5 time zone and at ~74’W.

Back in the 17th century, Sun King Louis XIV authorized the building of the royal observatory of Paris (today the Paris Observatory). On Midsummer’s Day 1667, scientists traced the outline of the building in such a way that the Paris Meridian bisected the site from north to south. Meridians were really important in that time as scientists attempted to determine the size and the figure of the earth.

The Paris Observatory

So we now have the Paris Meridian. What about Paris time?

Once upon a time and ironically long before the Sun King came along, people told time by the sun. Later, church bells calling to prayer marked time during the day. Each village, each town lived by the time of their local clocks.

It was only with the arrival of the train that France started to feel the need to unify time across its territory. In order to assure a regular train service, the train companies used Paris time. Progressively, over the second half of the 19th century, French towns adopted double display, local time and Paris time, and in 1891, Paris time was enforced by law across the country.

However, in the meantime, the Greenwich Meridian and GMT had been widely adopted around the world, first by navies, then by train companies and then (nearly) everyone else.

Finally, with the law of March 9, 1911, France adopted the time of the Greenwich Meridian and the division of the day into 24 hours instead of two times 12 hours. However, the text of the law never mentioned Greenwich. Indeed, the reference time remained “Paris time” which is 9 minutes and 21 seconds ahead of GMT. This corresponds to the distance between the Paris Meridian and the Greenwich Meridian.

La Mire du Sud – a sight that originally stood on the Paris Meridian in the gardens of the Paris Observatory, allowing to focus on the Meridian (today it can be found in the public Parc Montsouris)
Paris Observatory and Paris Meridian

In Paris, the Meridian is materialized both inside and outside the Observatory, as well as across town by the Arago medallions, named for Astronomer François Arago (1786-1853) whose statue near the observatory was destroyed by the Vichy Regime in 1942.

Many of the Arago medallions have gone missing since their installation in 1994, not least due to the Da Vinci Code, which has their location all wrong, so don’t go looking for one at the Louvre Pyramid! (Please don’t take any of the remaining medallions. Eiffel Tower key chains only cost 0.50€.)

And if you go to Villers-sur-Mer  in Normandy, you will find a marker materializing the Greenwich Meridian on the beach wall. That’s how much 2°20’ are in distance!

Location of the Paris Observatory on a map of Paris
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The Institut de France

The Institut de France is a French institution founded in 1795, located in the 6tharrondissement. It assembles the scientific, literary and artistic elites of France so they can work together. It regroups five Académies, the best-known of which is the Académie française.
The Académie française was founded in 1634 by Cardinal Richelieu to normalize the French language and is tasked with publishing an official dictionary of the French language. Its 40 members hold office for life, they are called the “immortals”.

The building also houses the Bibliothèque Mazarine, the oldest public library in France, founded by Cardinal Mazarin under King Louis XIV. It was his private library at first but was opened to the public in 1691.

Location of the Institut de France
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Le Val de Grâce

In 1645, seven-year-old Sun King Louis XIV, and his mother, Anne of Austria, laid the first stone of the Val de Grâce church. The queen mother this fulfilled an oath she had made earlier, to thank God for giving her a son.

Up until the French Revolution, the ^Val de Grâce was the church of the Royal Val de Grâce Abbey. It is located on the grounds of the Val de Grâce hospital. Thanks to the Benedictine nuns providing medical care to injured revolutionaries, the church was spared much of the desecration and vandalism churches such as Notre Dame and Saint Eustace suffered during the French Revolution. Still, it became a military teaching hospital in 1796.

It remained a military hospital until 2016 and treated normal patients as well as the French presidents Jacques Chirac and Nicolas Sarkozy during their respective mandates.

Today, only the training, research and museum activities remain on site. In 2020, the French president Emmanuel Macron announced it would house three new research institutes, a campus to be completed by 2028.

Location of the Val de Grâce
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The Paris Observatory

The Paris Observatory was founded in 1667 under Sun King Louis XIV and is the oldest observatory in the world still in operation.

It was to be situated on the Paris Meridian (today at 2°20′ East),  which was for a long time in competition with the Greenwich meridian. On Solstice Day 1667, mathematicians traced the lines on the ground where the observatory was to be built. The Paris meridian bisected the site. Today, it is traced on the ground inside the observatory, and the Avenue de l’Observatoire runs along its axis.

The Paris Meridian can also be traced in the city of Paris by the Arago medallions. 135 originally, some of them have disappeared since 1994. They are named after François Arago, director of the Observatory in the 19th century.

The first directors of the Observatory were four generations of Cassinis: Giovanni Domenico Cassini, Jacques Cassini, César François Cassini de Thury and Jean Dominique Comte de Cassini. They held the office until the French Revolution.

The copula of the observatory houses the Arago telescope. Completed in 1854, it was the biggest of its time, and remained in use for over a hundred years. In the 1880, it conducted photometry measurements of Jupiter’s moons (only four were known at the time, though).

Location of the Paris observatory
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La Sorbonne

The Sorbonne is a building in the 5th arrondissement in the Latin Quarter. It is named after 13th-century theologist Robert de Sorbon, founder of the Sorbonne College of the Université de Paris, college of theology. The term Sorbonne is also used as metonym for the former Université de Paris (1200-1793 and 1896-1971).

The Baroque façade belongs to the Saint Ursula chapel, completed in 1642. Following the law of the separation between Church and State, it was deconsecrated and is now used for receptions and exhibitions.
It was at the Sorbonne that Pierre de Coubertin founded the International Olympic Committee in 1894.

Today, the Sorbonne is the seat of the Paris Board of Education. It also houses part of the activities of the universities Paris 1 Panthéon-Sorbonne, Paris 3 Sorbonne Nouvelle and Sorbonne Université. The Sorbonne University Library serves all these universities and the Université de Paris.

Location of the Sorbonne
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The Panthéon – for great men and women

The Pantheon is located on the Sainte Geneviève mountain in the heart of the Latin Quarter. Built in the 18th century, it was originally meant to accommodate relics of Sainte Geneviéve, the patron saint of Paris, but since the French Revolution, it honors distinguished French citizens, as the inscription on the front says:

AUX GRANDS HOMMES LA PATRIE RECONNAISSANTE
To the great men, from a grateful nation

When the remains of a distinguished person are transferred to the Panthéon, they obtain a almost mythical status. Only very few panthéonisés have been directly buried there, such as Victor Hugo.
The “grands hommes” are still in a large majority men, the first woman was the wife of a grand homme whose family only agreed to the transfer if his wife’s remains could accompany his. The first woman to accede to Pantheéon status on her own merits was Marie Curie. Only three more women have followed her since, two Résistantes, and more recently, Simone Veil.

How do you become a grand homme? Only the national assembly can propose new candidates for the Panthéon, the final decision is made by the president.

Location of the Panthéon
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Le Dôme des Invalides

The Hôtel des Invalides (remember: not every hôtel is a hotel) is a building complex built on the orders of the Sun King Louis XIV for the invalids of his armies.
Today it is still true to its initial purpose, but in addition to a retirement home for war veterans, it houses the Army Museum, the military models museum Musée des Plans-Reliefs, the Museum of contemporary history, two churches (at the time one was for the soldiers, one for the royal family) as well as the tombs of several French war heroes. And of course, the tomb of Napoléon Bonaparte who died 200 years ago this year in exile.

The Dôme des Invalides can’t be mistaken for another one – it is covered in 12kg of gold that glitters in the sunlight.

Location of the Hôtel des Invalides
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Cupolas of Paris

There are a number of cupolas in the Paris skyline. In this new series, Cupolas of Paris, we will have a look at the most prominent ones and what is hidden below them:

  • The Dôme des Invalides – 7th arrondissement – built under Sun King Louis XIV in the 17th century
  • The Panthéon – 5th arrondissement – built in the 18th century
  • The Sorbonne – 5th arrondissement – built in the 17th century
  • The Observatory – 14th arrondissement – built under Sun King Louis XIV in the 17th century
  • The Val de Grâce – 5th arrondissement – built under Sun King Louis XIV in the 17th century
  • The Institut de France – 6th arrondissement – built under Sun King Louis XIV in the 17th century
1 Invalides – 2 Panthéon – 3 Sorbonne – 4 Observatory – 5 Val de Grâce – 6 Institut de France
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