The Measure of All Things

by Ken Alder

  What Méchain did not know—because no resident of Barcelona yet knew it—was that a new era was on its way. France and Spain were already at war, though the city had so far seen only signs of rising tension. In early March, the Spanish authorities ordered French citizens to leave the country, and Méchain had to petition to stay long enough to complete his report. Then, in late March, Méchain’s Spanish collaborators, military officers all, were ordered to report to their regiments. Commander Gonzales set out to sea in the Corzo to escort a supply convoy to the fortress port of Roses. This ended any hope of extending the meridian measurement to Mallorca. Méchain successfully pleaded to keep Captain Bueno with him. Without an escort he would never be allowed to visit the two frontier stations linking Spain and France.

  The two kingdoms had been close allies throughout the eighteenth century, each ruled by a branch of the Bourbon family, with common enemies in England and the German states. The stirrings of the Revolution had not altered this basic equation, at least not initially. Carlos IV, newly ascended to the Spanish throne, promised not to join the coalition against the Republic so long as his cousin Louis remained unharmed. The French Republicans decided to treat this promise as an ultimatum. Not long after they executed Louis XVI, the French preemptively declared war on Spain. Spain reciprocated two weeks later, then waited another two weeks before summoning Barcelona’s citizens with church bells to hear the Crown’s vow to root out the Revolution. That same day, April 4, the Spanish military command ordered Méchain to leave Mont-Jouy castle and dismantle his observatory. The army could not tolerate the presence of an enemy citizen in the most important fortress on Spain’s Mediterranean coast. Obliged to take up residence in the city proper, Méchain rented a room in an inn known as the Fontana de Oro (the Golden Fountain). The hotel was located just off the renovated Rambla promenade on the Carrer des Escudellers, a street known in the eighteenth century for its fine hotels and potters, and famous today for its prostitutes and pottery shops.

  Initially, the war on France’s southern frontier attracted scant attention from Paris, which was understandably preoccupied by the Prussian and Austrian armies two days’ march from the capital. Still, the fighting on the southern front was fierce. Tens of thousands of soldiers fought, and thousands died: regular troops for the Spaniards, and a mix of raw recruits and militia for the French. For more than two years the seesaw campaign would range up and down both sides of the Pyrénées. In the summer of 1793, Spain would seem on the verge of reconquering its former province of Roussillon, along with its capital city of Perpignan. In 1794, France would appear to be on the verge of conquering all of Catalonia, even Barcelona. For two years, troops, militia, and miquelets—some owing allegiance to France, some to Spain, and some to neither—would attack through high passes, lay siege to valley towns, and fight for coastal fortresses. These battles would remind both sides that the frontier was not a natural border, but a line drawn in blood, defended with arms, and as yet unmarked by science.

  In April 1793, however, Méchain still had reason to be satisfied, despite the disastrous turn of international events. His work in Spain was complete, and to his own exacting standards. Under the circumstances, he saw no harm in agreeing to take a long-delayed excursion with his friend, Doctor Francesc Salvà i Campillo. Salvà was one of Barcelona’s enlightened savants: a physician who had campaigned for inoculation against smallpox and for healthy fruit consumption, an inventor who had designed proto-railroads and submarines, a natural philosopher who corresponded with the leading physicists of Europe. He had long urged Méchain to visit an innovative pumping station on the outskirts of Barcelona, admired by English visitors for its mechanical ingenuity.

  When they arrived at the pumping station, however, they found it closed for the May Day festivities, with no horses in harness to drive the beam. Méchain pronounced himself content to examine the machinery inert, but Salvà insisted on putting the pump in motion. With the help of his manservant he set to work turning the eight-foot beam, while Méchain gauged the water level in the reservoir. Sudden sharp cries roused Méchain from his post. A rise in the water pressure had forced the beam to reverse course, and it was now dragging the doctor and his servant backwards across the floor. Méchain leapt to their aid just as they released the bar. Struck in the chest, he was hurled against the wall, where he slumped to the floor, apparently dead.

  A horrified Salvà and his manservant carried Méchain’s unconscious body to a nearby house, where the doctor—the leading physician in Barcelona—succeeded in reviving the Frenchman’s pulse, though he remained unconscious. Fearing the worst, they lifted him into the carriage and drove back to town. They arrived at midnight and immediately summoned Doctor Sanpons, the town’s best surgeon. The profusion of blood pouring from Méchain’s right ear made it seem doubtful that he would survive the night. Nonetheless, they bled him still more to prevent any build-up of fluid in his brain, wrapped him in sheep’s fleece, and put off any treatment of his wounds until morning. The next morning, Méchain was still alive—though unconscious—so they proceeded with their examination. The entire right side of his chest had been caved in, his ribs crushed, his collarbone broken in several places. They wrapped him in bandages and placed him under close surveillance. Three days later his fever broke and he regained consciousness. Later he would recall with rueful gratitude that “without Doctor Salvà my misfortune would never have occurred, and without his presence, I would not have survived.”

  Méchain was immobilized. And even if he had been able to rise from his bed, he had nowhere to go. Whereas a month before he had been obliged to petition to stay in Spain, he was now told he would not be allowed to leave until the war was concluded. The new governor-general, appointed to direct the war effort against France, feared that Méchain’s geodetic data might aid his Revolutionary adversaries. On top of this, the Spanish Treasury had impounded French assets for the duration of the war, and Barcelona’s bankers refused to supply Méchain with additional funds.

  No wonder a note of self-pity crept into the letter he dictated to his French colleagues—even as he downplayed the extent of his injuries. “I am unable to write this letter myself and it may lack coherence because I was badly injured two weeks ago . . . , though I certainly expect to be back on the job two weeks from now.” He neglected to mention that he had been injured on a trip unconnected to his mission. And he refused to admit the full extent of his injuries, for fear his Paris colleagues would replace him. Not only did he fear to lose his chance at glory, he could have no guarantee that his replacement would continue the mission with the same exquisite care.

  News of Méchain’s accident took a month to reach Paris, where it caused great concern. Thérèse Méchain was beside herself with worry. She had been anticipating her husband’s return by summer’s end. Now she wanted to travel immediately to join him in Barcelona. Lavoisier and the other academicians dissuaded her. It would be difficult, to say the least, for her to cross the border where battles were raging. She spoke no Spanish. Besides, the news from Barcelona was already a month out of date; perhaps her husband had already recovered and was on his way back to France. In any case, her place was with her three young children.

  For his part, Lavoisier wrote to Méchain to assure him that fresh funds were on their way. Already he had deposited 34,000 francs with the Barcelona banks in 1793. As Treasurer of the Academy, he would insist that the Spanish bankers honor drafts for a project “which concerns the commerce of all nations.” Moreover, he would personally guarantee the sum—and everyone knew Lavoisier was one of the richest men in France. In the meantime, Méchain should spare no expense in taking care of himself. Indeed, Lavoisier gently scolded his colleague for skimping on comforts, as he was wont to do. Such frugality was not commensurate with the supreme importance of his mission.

  In truth, we should reproach you for having practiced too great an economy—one might even say parsimony—with regard to your expenses. You must not forget that yo
u are carrying out the most important mission that any man has ever been charged with, that you are working for all nations of the world, and that you are the representative of the Academy of Sciences and all the savants of the universe.

  Above all, Méchain should preserve his health and treat himself as “a person precious to science, to France, to his colleagues, and to his friends.”

  Lavoisier wrote these noble words of consolation, exhortation, and financial relief in mid-June. The difficulty was to convey them to Barcelona. No letter of credit could cross the border because seals were being broken to prevent the transmission of military information. The circuitous mail route through neutral Geneva and Genoa was uncertain. The best Lavoisier could do was ask that the letter be transmitted directly from the French general in charge of the army of the Pyrénées to his opposing general on the Spanish side. Adversaries at war always maintained a channel of communication, and surely both parties would wish to aid an injured savant engaged on a mission approved by both governments and dedicated to the pursuit of knowledge for the common good. After all, as Lavoisier noted while pleading Méchain’s cause, “The sciences are not at war.”

  CHAPTER THREE

  The Metric of Revolution

  “A Global Scheme! Ah knew it!” Dixon beginning to scream, “what’d Ah tell thee?”

  “Get a grip on yerrself, man,” mutters Mason, “what happen’d to ‘We’re men of Science?’ ”

  “And Men of Science,” cries Dixon, “may be but the simple Tools of others, with no more idea of what they are about, than a Hammer knows of a House.”

  —THOMAS PYNCHON, Mason & Dixon

  I fear that the mathematicians, who have not yet troubled the world, will trouble it at last; their turn has come.

  —LOUIS-SÉBASTIEN MERCIER, The New Paris, 1800

  The French Revolution was not one thing but many things, although it was principally a contest to assert just what one thing the Revolution was. Paris was the arena where this contest was the fiercest. But across the nation, villagers, townspeople, and peasants also asserted just what the Revolution meant to them. For some, the Revolution was a noble struggle between a virtuous people and a parasitic aristocracy. For others, the Revolution was a civil war between godless usurpers and a loyal flock. Some proclaimed the Revolution a war of national defense; others, a movement of international liberation; still others, a war of foreign conquest. The Revolution, some said, was an attempt by Paris to bring the countryside to heel; others said it was an attempt by the provinces to establish their autonomy. Some saw the Revolution as a movement to liberate commerce; others, as a social struggle to guarantee a just price for bread. And always, everywhere, the Revolution was a chance to launch a career, make a fortune, join a parade, set out on an adventure, or bemoan the passing of the good old order. Electric promises of equality and panicked warnings of betrayal traveled in waves from Paris to the nation’s boundaries—and were returned: distorted, amplified, transformed. Like a body of water pelted with stones, the nation was roiled by waves that seemed occasionally to cancel each other out while, under the calm, pressure built for another surge.

  The moment the authorities unsealed his carriages and supplied him with new passports, Delambre rushed to Saint-Martin-du-Tertre to sight the Collégiale at Dammartin before the church was demolished for scrap. Thanks to the National Assembly’s declaration that the meridian expedition was a mission of national importance, he could move freely through the Republic. It helped too that two weeks later the French armies stemmed the Prussian tide at Valmy. The countryside calmed down for the harvest.

  Yet no sooner had human events broken his way than nature conspired against him. A northern gray autumn settled on the land. Every day that dismal September Delambre climbed the steeple of the church at Saint-Martin-du-Tertre to peer across the shrouded farmlands. But even though his angle calculations told him exactly where to look, he could pick out neither the Collégiale of Dammartin nor the Paris dome of the Invalides through the mist.

  Conditions in the church steeple hardly approximated the laboratory ideal. Wind and icy rains chilled the bones and clogged the repeating circle. Every toll of the bell seemed likely to shake the narrow belfry to pieces. Even a slight shift in Delambre’s weight unsettled the floorboards and rattled the instrument. Eventually, he turned the observations over to his young aides, Lefrançais and Bellet, who took fixed spots in the high cramped tower so they could alternate scopes without having to shift positions. Lefrançais was smaller than Delambre, and fit into the confined space more easily. And Delambre’s weak eyesight obliged him to adjust the focus every time he swapped scopes, enough to disturb the instrument.

  Delambre and his team would wait three weeks for a clear view of Paris from the narrow church tower at Saint-Martin-du-Tertre, only to discover, after a rainstorm finally cleansed the atmosphere, that a low hill had been blocking their view of the Invalides dome all along. This left the Panthéon as the only plausible Paris station, meaning they would have to redo all the measurements they had conducted since the beginning of their expedition in June. After four months of labor and danger, they had yet to travel more than forty miles from Paris, and were no further advanced than when they had begun. It was progress worthy of Don Quixote.

  With the days growing shorter and the northern skies darkening Delambre pressed on, reversing his route of the previous summer to work his way clockwise around the capital. He completed the Collégiale at Dammartin just before ownership transferred to the demolition men. He returned to the Château de Belle-Assise, the scene of his earlier arrest, to retake his measurements there, this time without incident. (In the nineteenth century, years after these measurements were done, the château would come into the hands of Baron de Rothschild, before being destroyed, all but an ancient windmill that still stands watch over the valley of Euro Disney today.) Delambre observed from the church at Brie-Comte-Robert in early November. And by the end of the month he was back in Montlhéry, where he had begun his journey half a year earlier, in what was now another historical era. This time he decorated his signal pole as a Liberty tree to placate local suspicions. The winter was advancing. The team lit an open fire at the foot of the ancient tower to warm themselves as they worked.

  Delambre had hoped to call a halt at that point and return to the capital for the winter, but the owners of the Malvoisine farm, who had kindly allowed him to elevate their chimney as a signal, feared the structure would collapse during the next winter storm and asked him to remove it. This meant he would first have to complete his observations from the Malvoisine roof and from all its adjacent stations. Among these Delambre had selected a site dear to his heart, one he knew with astronomical intimacy: the Château de Morionville, the country residence of his patroness, Madame d’Assy, located just outside the town of Bruyères-le-Châtel. On summer days before the Revolution he had often set his astronomical equipment on the terrace outside his rooms there, or conducted observations from his open window. Viewed from the rooftop of the farm at Malvoisine, Madame d’Assy’s garden door appeared in his scope like a black stain against a white background.

  DELAMBRE’S OBSERVATORY ATOP THE PARIS PANTHÉON

  This drawing of the cupola on top of the dome of the Paris Panthéon was annotated by Delambre and shows the position of the illuminated globe he used as his sighting target during his triangulations of 1792–93, as well as the special observatory the architects rigged for him at (C). The illuminated globe was a temporary replacement for the cross that had once capped the dome. In February 1793, just before Delambre returned to the capital, it was in turn replaced by a half-dome pedestal for a statue of Renommée (Fame). Note that Delambre has penciled in the various dimensions in the old Paris measures. (From the Archives de l’Observatoire de Paris)

  THE PARIS PANTHÉON CROWNED BY “FAME”

  In this drawing of 1794 the artist De Machy imagines how the Panthéon would appear were it to be capped by the statue of Renommée (Fame). A f
ull-scale model of the statue was made, but it was never installed on its pedestal. (From the Bibliothèque Nationale de France, Paris; Collection Destailleur)

  These were the last observations he conducted that season. As he surveyed his way south toward the outskirts of the royal forests of Fontainebleau, snow began to fall on the woods. In these conditions, geodetic measurements became impracticable. No sooner had Delambre finally worked his way out of sight of Paris than it was time to return to the capital. He would spend February and March at the top of the dome of the Panthéon—the central geodetic station for the city of Paris—triangulating all the sites surrounding the city.

  The Panthéon, commissioned by Louis XV as the Church of Sainte-Geneviève, had been on the verge of completion when the Revolution erupted. It had since been converted into a temporary warehouse for the thousands of old weights and measures sent in by provincial towns to await comparison with the new Republican measures. Now the nation’s leaders wanted to transform the warehouse into a mausoleum for the nation’s greatest heroes. The building’s monumental gray dome dominated the capital’s highest hilltop, and the Revolutionaries felt that its pure neoclassical form made it a suitable architectural rebuke to the Gothic obscurantism of the royal tombs at Saint-Denis.

  But first the Panthéon had to be stripped of its churchly attributes. First to go was the cross on top of the cupola, replaced with an illuminated globe. It was this globe that Delambre had used as his sighting target while he circled the city. The architects had still grander plans, however, and in November—just as Delambre slipped out of sight of the capital—they had replaced the small illuminated globe with a much larger half-globe pedestal, slightly flattened, upon which they planned to set a colossal female statue dedicated to Renommée (Fame). Already a sculptor had prepared a full-scale model of the bare-breasted thirty-foot figure, with a fifty-foot wingspan and a trumpet at her lips that would sound (if only metaphorically) “to the frontiers of France, and be noted from the middle of the ocean.”