The Paris Meridian

In 1667 a national observatory was built in Paris, south of the Luxembourg palace.

In 1669-70, Jean Picard measured by triangulation the distance from Paris to Amiens along the meridian that passes through the observatory, to calculate the size of the earth. (A meridian of longitude is a circle around the earth passing through North and South poles.)

Between 1683 and 1700 J-D Cassini measured the same meridian, this time across the length of France, to determine the size and shape of the earth. When the result was questioned, as a result of astronomical measurements, it was found that Picard’s baseline measurement was inaccurate. (The baseline, in this case a 5,500 toise (eleven kilometre) line from Juvisy to Villejuif, is the only line measured on the ground; all over measurements are established by trigonometry. Later surveys used two baseline measurements, Juvisy-Villejuif, near Paris, and Vernet to Salse, near Perpignan.)

In 1739-1740 Lacaille resurveyed the Meridian. In 1747 a map of France was produced in 18 sheets at a scale of 1:870,000.

In 1750 a new survey and mapping of France was begun, at a scale of 1:86,400.  It took until 1800 to produce the 182 sheets. Robb gives a vivid account of the confrontations between the surveyors, modern wizards building strange towers and pointing mysterious instruments, and the superstitious peasants of la France profonde.  

Between 1791 and 1799 the Paris meridian was measured again (by Delambre from Dunkirk to Rodez, by Méchain from Rodez to Barcelona), to determine the size of the earth, and derive from it a new, universal measure, the metre, one ten millionth of the distance from the pole to the equator. From 1817 to 1866 France was remapped from the Paris meridian at a scale of 1:80,000.

So, although in 1884 the Paris meridian lost out to Greenwich as the world prime meridian, it has been, since the establishment of the modern French state as l’Hexagone from 1659, central to French self-definition.

(French rationalism triumphed, of course, in world-wide metrication. Initially with ten-day weeks, ten-month years, what the British call, ‘taking it to extremes’, quoting the Delphic ‘nothing in excess’. To which the Frenchman replies, triumphantly – ‘not excess, simply the logical conclusion’. ‘Exactly my point,’ the Englishman sighs.)

And for the millennium the Meridian was given renewed significance by its designation as la Méridienne Verte. Banners on the route proclaimed:

‘On 25 November 1999, “la Meridienne Verte prend racine [takes root], des arbres par millers [trees by the thousand].” (10,000 are planned, one every hundred metres, oaks in the north, pines in the centre, olives in the south.)
18 June 2000 “Ouverture du chemin de randonnée Dunkerque à Barcelone” [opening of the excursion route Dunkirk to Barcelona]
July 2000 “Variations sur toute la ligne, 20 sites en fleur.” [various events along the length of the line. 20 places in bloom]
14 July “l’Incroyable Pique-Nique.” [the Incredible Picnic].’

On Bastille Day was held la fête du Millenaire, “the biggest party in history”, in each of the 337 towns and villages on the meridian. Runners, cyclists, horse riders and balloonists took part in relay races along its length, 2000 racing pigeons from Perpignan were released in Dunkirk and sped unerringly along it, home. A line of flapping red-and-white-check tablecloths in every village, uniting the French in Frenchness.
But also, with the changing drinks and foods on those tablecloths – frikandelle and Chti beer on the Channel coast, duck paté and leek pie in Picardy, the thousand cuisines of the Île de France and Paris, coq au vin in Berrichonne, wine of Berry, river fish and white wines in the Loire valley, pork and cheese with light reds in Auvergne, and cassoulet and the heavy red wines of the Midi; and the voices around those tables, the different accents, dialects, languages of France, from Flemish to langue d’oil, langue d’oc to Catalan – giving notice of difference, the importance to the French of region, locality, of pays (from the Latin pagus, the smallest Roman administrative unit, retained in Merovingian and Carolingian times). When de Gaulle said, “how can anyone govern a nation that has 246 different kinds of cheese?”, he was speaking with pride as well as exasperation.

After the food and drink, the ceremonial unveiling of hundreds of markers, on posts and walls, in every commune, marked “An 2000 – la Méridienne Verte“. And, over time, as the trees grow, would come the greening of the line.

Now, fifteen years on, they should be well grown, each tree visible from the next, a relay of trees across plains, through forests, over mountains, from sea shore to mountain frontier, that I will follow …

The Celtic Meridian

Graham Robb’s The Ancient Paths: Discovering the Lost Map of Celtic Europe was reviewed as ‘an overarching, wondrous reworking of history rooted in painstaking research’. ‘Presenting one of the most astonishing, significant discoveries in recent memory, Robb, winner of the Duff Cooper Prize and Ondaatje Award for The Discovery of France, upends nearly everything we believe about history – or, as he calls it, protohistory – of early Europe and its barbarous Celtic tribes and semimythical Druids.’ His thesis, briefly, is that Celtic scientists mapped the heavens onto the earth (‘as above, so below’), creating a vast and intricate geographical latticework that structured their society. The lines relevant here are the Celtic Meridian, parallel to and 10km west of the Paris Meridian. And the Heraklian Way, from the Sacred Promontory on the coast of SW Portugal, across the Pyrenees, crossing the Paris Meridian at Pic de Bugarach. It meets Robert Coon’s Eagle Line (from Glastonbury through Shaftesbury to Delphi) in Switzerland. These two lines, with the Meridian, create an equilateral triangle.

Latest archaeological research, especially by Barry Cunliffe and John Koch, places the origin of the Celtic language exactly in the area of the Sacred Promontory. (The Celts, Roberts p 233.)

Graham Robb, The Discovery of France p187, 346
Graham Robb, The Ancient Paths p4, 65