Hello and bonjour-euh !
It is a wintery February day and I’m in central Paris.
Because have you ever been wandering around the courtyard of the Louvre
(as you do)
and found a small metal disc in the ground with the word Arago written on it?
[Tim] Found one!
Let’s face it, you probably haven’t.
I mean, what kind of person comes to the Louvre
and then spends their time staring at the ground?
But if you know where to look, you can find more of these Arago discs
- and not just at the Louvre.
There’s another one here,
another one here x2
another one here x3
another one here x4
another one here x5
...you get the idea.
And if we zoom out for a second
and start to plot their locations on a map
you might notice something.
They are all in a perfect straight line north to south through the city.
Because what we are looking at here is the old Paris Meridian,
which was once as famous as the more famous Greenwich Meridian,
but is now nowhere near as famous.
So today we’re going to follow the route of the old meridian through the centre of Paris,
and along the way we’re going to try and answer the question:
how close were we to using the Paris meridian instead of Greenwich?
This is the story of the Greenwich meridian’s forgotten rival.
Ok before we start, let’s just quickly define what a meridian is and what they do.
If you draw a straight line from the north pole to the south pole, that is a meridian.
Doesn’t matter where you draw it,
as long as it goes straight from one pole to the other, it’s a meridian.
But what we’re really talking about today is what’s called a prime meridian,
and that’s when we all agree on one chosen meridian line to be the zero line on all maps,
and then we use that line to calculate things like coordinates,
and degrees east and west, and all that stuff.
So for example, if you’re in the military,
and your commanding officer asks you to attack the target at 51.631 North 0.264 West,
it’s kind of important that you’re both using the same meridian.
And it’s only really the last century and a bit that the world has agreed on Greenwich.
Before that, different countries drew their maps using their own meridians:
France had the Paris meridian,
the United States had a Washington meridian,
Spain had a Madrid meridian...
in fact the idea goes back at least as far as the ancient Greeks & Romans,
and would you like to guess where the Romans put the Roman meridian?
That’s right: the western end of the Canary Islands.
The reason the Romans put their meridian there
is because their numbering system didn’t have negative numbers,
so they simply stuck the line at the westernmost point
of the westernmost piece of land they knew about,
and then all they had to do was count upwards.
As a result, this line eventually became known as the Ferro Meridian,
or the El Hierro meridian,
named after the island at the western end of the Canaries.
Anyway, fast forward a millennium and half to the 1600s
and French maps are still using the Ferro meridian.
Or at least... sort of.
What they were actually doing was shifting the meridian very slightly further west
so that they could put Paris exactly on the 20 degree line.
But then one day King Louis XIV said
"This is stupid is it not?
If we want to draw the line through Paris,
why don’t I just make Paris the meridian?”
And thus the Paris meridian was born.
The King was a huge supporter of science, so on top of the new meridian
(and I mean that in most literal way possible)
he also approved the construction of the Paris observatory.
- I think it's that way.
This is now the oldest observatory still in operation,
but at the time it was a massive boost for French scientists,
partly because it allowed them to make more accurate maps,
but also because they wanted to do things like geodetic surveys,
and measuring the arc of the earth,
and then use those measurements to start creating the metric system.
And of course all those complicated calculations are made that little bit simpler…
...if your zero line just happens to be in the middle of Paris,
directly underneath your newly-built national observatory.
So France was way ahead on this stuff.
Paris had established both its meridian and its observatory before Greenwich did.
And over the years some incredible work was carried out here by some incredible nerds.
There are far too many of them for me to mention them all,
but there is one that I need to mention,
and that is an astronomy student from the early 1800s
called Francois Arago.
- Bonjour !
In 1806, at the age of just 20,
Arago was selected to travel due south and finish the work of the previous nerds
by measuring the path of the Paris meridian through Spain and Algeria.
The job took him 3 years to complete,
not helped by the fact that France declared war on Spain while he was there,
- Excuse me lads, can I just measure some stuff?
and he was promptly imprisoned by the Spanish who thought he was a spy,
- No really I just want to measure it
but he eventually escaped and returned to Paris with his results.
- Bonjour, c’est moi !
Arago was welcomed back as a hero.
Thanks to his hard work, France was now the proud owner
of the world’s most accurately measured meridian.
Which you can tell, because even German maps had started using it.
(Although admittedly, that might also have something to do with Napoleon,
who currently controlled most of Germany.)
But either way,
with France producing the best maps in the world,
and Napoleon defeating every army Europe could throw at him,
it was beginning to look like the Paris meridian could become THE meridian.
So where did it all go wrong?
Well, it begins to go wrong when Napoleon starts losing.
First he loses that war in Spain,
and then he loses in Russia,
and then the battle of Leipzig,
and finally the battle of Waterloo.
And this changes everything.
Because with the French army fundamentally nobbled (technical term),
the British are now free to head off to sea,
build a global empire,
and in their own words,
"rule the waves."
A side effect of which is that Britain starts producing the world’s best navigational charts,
which everyone else starts using,
which means half the planet is now using...
the Greenwich Meridian.
So that’s one chain of events.
And then there’s a second chain,
which begins when the British (yes, them again) invent the steam train.
Ok - how does a chuffing steam train change which meridian we use?
Well, it's more than that: they changed the concept of time.
Until then, every city used to run its clocks on their own local time,
depending on how far east or west you were.
So Oxford was 5 minutes behind London,
and Bristol was another 5 minutes behind Oxford.
But the moment we had the railways, we needed to have timetables,
and the moment we had timetables, we needed to synchronise our clocks,
because if we continued having different time in different cities
that would be, at best, confusing for passengers
and at worst, it could cause accidents.
- What are you doing?! It’s 12:00, I’m supposed to be here.
- No it’s not, it’s 12:05, I’m supposed to be here.
So effectively the railways forced us to standardise our clocks.
Britain standardised on Greenwich time,
and France standardised on Paris time.
But meanwhile over in the United States, they had a problem.
- Gosh darn it! Looks like we’re going to have to standardise our clocks as well.
- Sure, but how do we do it? America’s just too big to have one standard time.
- Yeah what are we going to do?
- Wait a minute. I’ve got an idea!
The brilliant solution the US railroads came up with
was a thing called "time zones".
And they split the contiguous states into 5 time zones,
which later became 4,
with clocks set to 5, 6, 7, and 8 hours behind London;
in other words, from the start, the system was based on Greenwich.
And these time zones worked so well in North America
that the rest of the world started to say
"Hang on. Why don’t we all do this?
We could split the entire planet into 24 equal time zones
each one 15 degrees apart.
All we need to do is agree where the zero line goes."
And of course, that zero degree line could have gone anywhere.
But there were two stand-out candidates,
and I think you can guess what they are...
the Paris meridian, and the Greenwich meridian.
So in 1884, a conference was organised
bringing together the best map experts from 25 different countries
to make the final decision.
And to summarise what happened,
the French delegation argued:
- Euh... we think the best solution is the Paris meridian,
because it is French, and therefore it is better.
Meanwhile the British delegation argued:
- Er, no.
We should use the Greenwich meridian,
because it is British, and therefore it is better.
And also because most of you are using it already.
And after a long debate
(because the decision was a bit more complex than I just made it look)
22 of the 25 countries present voted in favour of Greenwich.
The world had made its decision.
And that meant that, unfortunately, after all that work by all those nerds,
this was the end for the Paris meridian.
Except it wasn’t!
Because France reacted to the result by completely ignoring it
and continuing to use the Paris meridian for nearly 30 years.
For example, here is a French map from 1890, still proudly using the Paris meridian,
and they also refused to change their clocks,
which meant when everyone else standardised to the new time zones,
France ended up in its own time zone,
precisely 9 minutes and 21 seconds ahead of London.
In fact it wasn’t until 1911 that the French government finally gave in
and quietly moved to Greenwich Mean Time.
Or as they called it,
"Paris time [delayed by 9 minutes and 21 seconds]."
And in theory, that WAS the end of the Paris meridian.
Except... to this day, French law has never mentioned the word "Greenwich".
So France officially remained on Paris time
[delayed by 9 minutes and 21 seconds]
up until the 1940s,
when the Nazi occupiers moved it into the Berlin time zone
and made everyone wake up one hour earlier in the mornings.
And as if you didn’t think the Nazis were bad enough already,
they then took down the statue of Arago that used to stand on the Boulevard Arago,
and destroyed it in order to make weapons.
The statue has never been replaced.
Which feels a bit rough on poor old Arago.
So in the 1990s, Paris decided to commemorate him instead
with a series of little brass discs running through the city,
along the old meridian line,
leading you to the exact spot where his statue isn’t.
In other words,
this really is the end of the Paris meridian.
(Technically, wouldn’t the end be at the North Pole?)
If you’re in Paris some time soon
and you’d like to follow the path of the meridian,
I’ve created a walking route on Google Maps and I’ll put a link in the description.
Although let’s face it, it’s not complicated:
basically you go to the Louvre and then head due south,
avoiding the occasional building.
Meanwhile the route is completely flat and should be fairly accessible to anyone,
although there are a few narrow pavements in the left bank area.
And that’s about it for today.
As always, thank you very much for watching,
and I’ll see you soon.