"Guedj's novel is the story of the origin of the meter, a seemingly dull subject. Wrong. It's a tale of adventure, drama, comedy and danger and its background is the turbulence and terror of the French Revolution. . . . Arthur Goldhammer's translation from the French is miraculous."Roy Herbert, New Scientist
"He has chosen to present the story as a novel but one populated by many real-life personages. Foremost among these are Jean-Baptiste Delambre and Pierre Méchain, eminent astronomers appointed by the French Academy in 1792 to survey the meridian from Dunkirk to Barcelona. . . . But historical eventsin particular the French Revolutioninterrupt the project. Regimes topple and buildings chosen as survey stations are blown up. . . . [T]his book will be of particular interest to readers who enjoyed Dava Sobel's nonfiction book Longitude."Booklist
"With scrupulous detail and passionate attentiveness, Guedj follows the two scientists appointed to the huge task of measurement . . . as they go on their individual six-year odysseys . . . 'Seldom has history been so inextricably intertwined with the history of science,' comments Guedj. And seldom have such interesting books as his come from that union."Kirkus Reviews
An excerpt from
June 24, 1792. The Tuileries still bore traces of the human tide that had just washed over them: discarded food wrappings, deposits of excrement, bits of rag, trampled flower beds. A handful of gardeners gauged the damage, deliberately turning their backs on the sapling that a procession of marchers from the faubourgs had planted three days earlier over the objections of the king's guards. It was a fine tree, which would survive until at least the end of the century if nothingneither stroke of lightning, ax blow, fire, nor parasitesinterfered with its growth. Pinned to its trunk was a tricolor cockade in all its splendor.
At the end of the drive, parked back-to-back in front of a wing of the palace, stood two heavily laden berlins, ready to depart. Identical but for their colorone was green, the other bronzeeach was fitted out in the rear with an enormous, oddly shaped trunk. In the vicinity of these two carriages a small group had gathered: Lavoisier the distinguished chemist, Condorcet the philosopher and deputy of the Legislative Assembly, and the Chevalier de la Borda, a physicist. With them stood a woman and her three children.
This small group had gathered to bid farewell to Citizens Pierre Méchain and Jean-Baptiste Delambre, who were about to depart the capital.
"So then Méchain," Delambre greeted his partner. "The south for you, the north for me."
"So says the Assembly," the other man replied.
"And I'm staying in Paris," Lavoisier gloomily remarked as he handed each man a small strongbox containing letters of credit and pieces of gold and silver. Then Borda handed each traveler a briefcase containing passports and letters of recommendation signed by the king.
Thérèse Méchain tried hard to hide her anxiety. Dignified and silent, she remained aloof from the others. But as Delambre approached to take his leave, she could no longer contain herself. "If only you were going with him!" she blurted out. At this point Condorcet joined the two of them. He would stay in constant touch with both travelers, he reassured Mme Méchain, and would share any news with her the moment he received it.
Méchain climbed into the bronze carriage, Delambre into the green. Their eyes met. Did they really glow, as they seemed to, with the excitement of departure, or was the gleam merely a reflection of the bonfires of Saint John that had illuminated the heights of Montmartre for the past several nights?
"To Rodez! To Rodez!" both shouted simultaneously.
The two berlins shuddered into motion at the same time, heading off in opposite directions.
For Lavoisier this day marked an anniversary. Nine years earlier he had gone to work as usual in his laboratory at the Arsenal. That morning, by combining flammable air and vital air in a sealed bell jar in precisely calculated proportions, he had createdwater! A few dropsof matchless purityhad formed beads on the glass walls of the jar. Water from the inception!
Out of gases had come water! Hence one of the four elements that according to ancient myth made up the world was in fact a compound substance. This discovery spelled the end of man's belief in primary elements, in aristocratic substances that outranked all the rest. A revolution! As he left the Palais des Tuileries, Lavoisier, remembering that he was one of the fathers of the Republic of Matter in which all substances enjoyed equal rights, could not suppress a momentary fear that another Republic, this one not of Matter but of Men, was even now being born.
Alongside him walked Condorcet, whose sympathies were precisely the opposite of Lavoisier's. As a philosophe, the sole surviving Encyclopédiste, and president of the Legislative Assembly, he hoped that the Republic's time had come: better a sovereign who is absent, as he put it, than a sovereign who is present. As for Borda, despite his devotion to the monarchy, he had fought with the American "insurgents" in their battle to free themselves from the English crown.
The three men had not gathered in the courtyard of the Tuileries to debate the best form of government, however. They had come as overseers of a mission that the Assembly had authorized and the king approved. Why, then, was Thérèse so apprehensive?
It was not the first time her husband had been sent on a mission. But so much had happened in the past three years! Why, the very buildings of the Tuileries now had new names, and their occupant a new title. What had been the Pavillon de Marsan on the north side was now called Liberty. The pavilion in the center had been dubbed Unity, while Flore, to the south, was now Equality. Over all three buildings a tricolor pennant now flew day and night. As for the king of France, his title was henceforth "king of the French," and people now called one another "Citizen" and the old constable's corps, the maréchaussée, had been renamed the Gendarmerie Nationale. Just a week earlier, and only a few feet from this very spot, a great bonfire had been lit, and into it had been tossed the "playthings of the nobility": an enormous batch of letters patent and parchments attesting to the nobility of dukes, marquis, viscounts, and counts had been set ablaze at the foot of the statue of Louis XVI, which the flames had licked for hours. The patente, a new tax on professionals, had been enacted, and throughout France the right to own so much as a single slave had been abolished. Meanwhile, the Sorbonne had been closed, and Corsica had been opened up to the Continent. The bridge at Avignon had become French. And steps had been taken to root out the dialects and patois that prevented citizens from understanding one another, or so it was claimed.
If variety of dialect was undesirable, so was diversity of weights and measures. Wood for the fire was sold by the cord, charcoal by the hamper, peat by the basket, ocher by the barrel, and framing timbers by the mark or joist. Fruit for cider was sold by the poinonnée; salt by the muid, sétier, mine, minot, boisseau, and mesurette; lime by the poinçon; plaster by the bag. Wine could be bought by the pinte, chopine, camuse, roquille, petit pot, or demoiselle. Spirits were sold by the potée, wheat by the muid and écuellée. Fabric, carpeting, and tapestries went by the square ell. Woods and fields were measured in perches carrées and vineyards in daurées. An arpent, or acre, equaled twelve hommées, an hommée being the amount of land one man could till in one day. So was the oeuvrée. Apothecaries weighed in livres, onces, drachmes, and scrupules. A livre was equal to twelve onces, an once was eight drachmes, a drachme three scrupules, and a scrupule twenty grains.
Lengths were measured in toises and pieds de Pérou, one of which was equal to one pouce, one longe, and eight points du pied du Roi: this "king's foot" was that of Philicteres or of the king of Madedonia or the king of Poland; and there were also feet of Padua, Pesaro, and Urbino. The king's foot was approximately equal to the old foot of Franche-Comté, Maine, and Perche, although surveyors still used the foot of Bordeaux. Four of the latter were close to one aune, or ell, of Laval. Five made up the Roman "hexapod," which was equivalent to the canne of Toulouse and the verge, or rod, of Norai. This was the same as the rod of Raucourt as well as the corde of Marchenoir en Dunois. In Marseille the canne used to measure line was longer than that used to measure silk by roughly one-fourteenth. Imagine the confusion with some seven or eight hundred different units of measurement throughout the kingdom.
"Deux poids et deux mesures!" Two weights and two measures: the slogan captured the very essence of inequality, the notion of a "double standard." The Revolution, responding to grievances expressed not only by villages throughout France in 1789 but also as early as the Estates General of 1576, which had insisted that "everywhere in France there should be but one yard, one foot, one weight, and one measure," decided to enforce uniformity. It established a single standard system of measurement, thus facilitating trade and encouraging greater honesty in commercial transactions.
After leaving the Tuileries and passing without difficulty through the customs barrier around Paris, the bronze berlin headed due south across the countryside. Inside, with windows open and curtains lowered to allow a cool breeze to enter, Méchain sat comfortably and observed the man opposite him, who had already fallen asleep.
For Méchain had not set out on this mission alone, any more than Delambre had. Each was accompanied by an assistant: Citizen Bellet for Delambre, and Tranchot for Méchain.
Tranchot had the reputation of being a stalwart country fellow, strong-willed but competent. His familiarity with mountainous terrain would be invaluable when it came time to brave the Catalan peaks, the Pyrenees, the Corbières highlands, and the Montagne Noire. Méchain, staring at his companion's small hands as they lay idly on his thighs, guessed that they would prove agile and strong. Watching Tranchot as he slept, he sensed that this was not a man who worried overmuch about his inner weather. That was exactly what he wanted. The coach drove through a village. Méchain glanced outside and saw puzzled looks on the faces of the inhabitants. Was it the unusual construction of the carriage that drew their stares? Méchain settled into a comfortable position and set a small collapsible table into position. He then spread out a map of Catalonia and began to study it.
The carriage braked so suddenly that Tranchot was thrown from his seat onto the seat opposite, pinning Méchain's arm. "Citizens, your passes." The order of the officer of the National Guard who now appeared before them went unanswered. Méchain looked down at the smashed table, rubbed his sore arm, and picked up his map, which he tried absent-mindedly to smooth. The officer repeated his order. Dazed, Tranchot picked himself up. Through the window he caught sight of a rifle barrel glinting in the sun: the carriage was surrounded. Méchain remained silent while Tranchot tried to explain the nature of their mission to the officer. The officer listened politely but gave orders to search the carriage. Méchain, striking a hostile pose, seemed determined not to collaborate with the men carrying out the search. But Tranchot, who understood the reason for these checkpoints, displayed no ill will, for he knew that dozens of aristocrats and prelates were fleeing the country every day, taking their fortunes with them.
The search turned up neither arms nor jewels: only two letters of credit addressed to Spanish bankers. The soldiers were about to let the berlin pass when one of them discovered twenty sealed letters in a briefcase that had fallen under one of the seats. The officer wanted to open them, but the soldier objected, pointing out that the Constituent Assembly had issued a directive prohibiting the breaking of official seals unless an elected municipal official was present. The officer accepted this and sent someone to the nearby village of Essonnes to find the procureur-syndic, roughly the equivalent of a mayor.
Upon his arrival, the procureur took one of the letters, broke the seal, and at the request of the soldiers read it out loud: "The king recommends to the administration of la Creuse Messieurs Méchain and Delambre, astronomers of the Academy of Sciences."
"Where is this Delambre?" asked the officer. Since Méchain was still refusing to speak, Tranchot explained that Delambre was at that moment headed toward Dunkirk, while he and Monsieur Méchain were on their way to Barcelona. The official continued his reading: "Louis, by the grace of God and the constitutional law of the State King of the French: To all, now and to come, greetings."
Since the letter had been signed by the king, the majority of the guards agreed that the berlin should be allowed to pass. But one spoke up to point out that there were twenty more letters whose contents had yet to be examined. The procureur broke the seal of a second letter. It was addressed to the département of Aveyron. A third, to the département of the Tarn. A fourth, to the département of the Pyrénées-Orientales. The contents were identical.
The letters whose seals had been broken were spread out on one of the trunks that had been removed from the carriage. Those that remained sealed were neatly arrayed on a second trunk.
A driver whose oxen were grazing in a nearby field came over to see what was going on. A group of peasants on their way home from the fields joined him, abandoning their wagons and carts along the road. Several private carriages also stopped, and their occupants joined the swelling crowd of onlookers. As the letters were read everyone listened attentively, and they quickly realized that each new missive simply repeated the contents of the previous ones. Sitting off to one side, Méchain seemed to take no interest in the proceedings.
By now six letters had been read. Some of the assembled wanted to hear them all. Fifteen remained unopened. Suddenly the astronomer stood up. Brushing aside the curious, he marched straight up to the procureur-syndic and stated flatly that all the letters were identical. He then proposed a way of expediting the procedure. As an expert mathematician and specialist in the laws of probability, he suggested that a letter be chosen at random. If it was identical to the others, he should be allowed to proceed; otherwise he should be arrested on the spot. The spectators approved of this proposal because it meant that they would learn the outcome of the incident without having to stand around for hours in the middle of nowhere.
Everyone drew closer. The children were told to hush, and silence settled over the crowd. Tranchot took up a position alongside Méchain, his back to the carriage. The decisive letter was in the hands of the official, who slowly removed the seal. After quickly reading it over, he smiled: "The king recommends, etc." A shout went up. Tranchot squeezed Méchain's arm in a friendly way, and some of the onlookers hastened to congratulate them.
"The longest geodesic measurement in history, as Borda called it, is off to a bad start," Méchain grumbled as he climbed back into the carriage. A navigator, physicist, and inventor of instruments, Borda had just perfected a marvelous new device, a repeating circle. Two of the three existing specimens were packed away in Méchain's trunks.
How long would the expedition last? The optimists were saying a year. Méchain thought it would be at least two. The truth was that nobody really knew. Not the deputies in the Assembly who had sponsored the project, nor the scientists of the Academy who had discussed the principles involved, nor the members of the Commission on Weights and Measures who had done the planning. Sitting in the gallery of the Constituent Assembly and, later, the Legislative Assembly, Méchain had dutifully attended to the speeches of Talleyrand, Condorcet, and Prieur of the Côte-d'Or. He remembered his emotion when Condorcet, speaking to a chamber full to the bursting point, had dedicated the expedition "to all nations and all ages." Now there was a fellow who knew how to turn a phrase, but Lord, what a terrible speaker! Méchain could remember what he said almost word for word: "In carrying out this measurement, which is destined to enlighten all mankind and bring nations closer together, we must choose the right course: not that which is easiest but that which will yield the most perfect result possible."
What measurement was he talking about? Why, nothing less than to determine as precisely as possible the length of the meridian between Dunkirk and Barcelona. This was the daunting task that Méchain and Delambre, both astronomers and members of the Academy, had been chosen to carry out. They would start at opposite ends of the meridian and work their way toward Rodez, where they would meet at the conclusion of their work.
Unity in language, unity in government, unity against all enemies foreign and domestic: for three years everyone had been obsessed with unity, abhorred the arbitrary, and felt universal.
Measurement is quantity: that is why it exists. But people wanted it to be "quality" as well, hence universal, eternal, and invariable. Anything that stands alone, that depends on nothing else, that is arbitrary, is not fit to be adopted as a permanent standard, they insisted. As proof they cited the long history of humankind.
It had therefore been decided that any new unit of measurement must for the rest of time be intimately linked to changeless objects rather than to anything dependent on the vagaries of human decisions or events. What possessed the requisite qualities other than Nature? And what in Nature was more apt than the terrestrial globe itself to guarantee constancy, universality, and eternity?
Everything was in place: the time, the men, the institutions, and the technical resources. This, then, was the solemn moment of definition. It was proclaimed that the new unit of length would be a piece of the globe: "one forty-millionth of the circumference of the meridian."
Méchain tried to relax. He stretched out his legs. This berlin was comfortable indeed! Borda had overseen every detail of its design. A marvel of ingenuity: There was a folding table with extensions that could be used as a work surface. The well-upholstered seats could be converted into beds for two. Niches fashioned in the wooden walls served as storage compartments for various instruments: a traveling thermometer, a clock calibrated in seconds and another equipped with an alarm, two capillary hygrometers, two barometers, a compass, a small level, and two pocket magnifying glasses in their patent leather cases. A compartment in the ceiling held a bundle of maps. Borda had thought of many other clever systems as well, but Lavoisier, the Academy's treasurer, had put a stop to any further expenditure of funds.
The berlin was once again moving along at a good clip. Essonnes receded into the distance. Seated next to the coachman, looking down on the horses' hindquarters glistening with sweat, Tranchot admired the perfection of the mechanism that was transporting him to Spain. The first of the three-horse team raced ahead into the thickening dusk, and the two other horses followed blindly. The coachman dozed but kept a loose grip on the rawhide reins.
Tranchot had been upset by Méchain's behavior, at first irritated by his lack of emotion and then angered by his dejection, but in the end he had been won over by his companion's sudden burst of energy and skill in extricating them from an unpleasant situation. Méchain had the reputation of being a man who kept to himself. Like the pair of horses in the rear of the three-horse team, he and Méchain had no choice but to march in step. For months, perhaps even years, they would be sharing everything: the same jobs, the same meals, the same carriage, and more often than not the same bedroom. A regular marriage! The thought made him smile. A consensual marriage, he had to admit.
Was that Méchain's voice? It was hard to hear because of the wind. Tranchot turned around. Leaning out the window, the astronomer was shouting at the top of his lungs, but it was impossible to hear what he was saying. The carriage slowed to a stop, and Tranchot leaped down. Without opening the door, Méchain ordered the coachman to turn around. "We're going back to Paris! To be arrested, checked, and searched every step of the way! As if the natural obstacles weren't enough! I've decided to postpone the expedition."
"But th-that's impossible," Tranchot stammered. "Delambre has already left. He won't be turning back." The last sentence was uttered in a deliberately provocative tone. "And besides, Captain Gonzales will be waiting for us at the Spanish border. There won't be any second chance. If you put it off, you sink the mission."
"It's already sunk. You saw what happened. You saw how they treated us."
"All they did was check up on us and slow us down by a few hours. But we were allowed to continue."
Calmed down, Méchain grumbled a few more words, addressed more to himself than to his assistant. "We won't succeed unless we can count on the help of local officials, policemen, and ordinary citizens. We'll need carpenters, wood, porters, animals at every step of the way. No, it's impossible. The expedition has to be postponed."
"You don't understand, then," Tranchot erupted, emphasizing every word. "Things are not about to calm down! This is not a riot or peasant uprising. This is a revolution. If we go back to Paris, we won't be able to get out again for years."
Night was almost upon them. The next way station was still leagues away, but the bronze berlin had not moved. The coachman, sitting in the grass, his pipe in his mouth, was waiting for Méchain to make up his mind: would it be north and back to Paris, or south? He stood up. "Not to butt in," he said to the astronomer. "I don't make a habit of sticking my nose into other people's business. But I think he's right. What's happening now isn't going to be over tomorrow, believe me. And it's a good thing, too."
The astronomer climbed back into the carriage and called Tranchot, who was pacing up and down the road to calm himself down. "So what do we do?" the coachman asked. Méchain pointed to the south. "Head for Catalonia," he said.
The moment the berlin started to move, Méchain swore an oath to himself not to return to Paris until the meridian had been measured.