by Ken Alder
The native son of verdant Picardy, dazed by the light of the summer Riviera, sat by the writing desk in his darkened hotel room and considered his dilemma from every angle. Emigration was a capital offense. Even the rumor that he was contemplating emigration might cost him his position, the livelihood his family depended on, and any hope of ever returning to France. Yet how could he return there now? He had been sent out on his mission with the best technology in the world. He had made himself personally responsible for the observations. And he had performed the calculations according to the most reliable methods. Yet the results were inconsistent. Méchain could not bring himself to blame the instruments or the calculations. He blamed himself. And if he blamed himself, then surely others would do so too. In a rare display of understatement he informed Slop: “I have been through some tough moments since I left you [in Pisa], but it is all my fault. I have placed myself in the hands of chance when I should have stuck to the path of certainty. One must suffer and not complain, or risk suffering still more.” He told himself to put the past behind him and think only of the present and the future. Yet he could not help but worry and he could not help but complain.
In early October the French ambassador to Genoa was recalled to Paris to account for his Jacobin sympathies, and his replacement, Ambassador Villars, arrived with funds and passports to speed the team’s return. The time had come to leave Genoa. Tranchot went down to the warehouse to pack the instruments for their voyage. Calon asked that the instruments travel across the Alps by mule, for safety’s sake.
Méchain publicly announced his intention to return. Indeed, he wrote to the prominent Milanese astronomer Barbera Oriani (whom Méchain had met a few years before in Paris) to tell him he would be leaving Genoa “on the thirteenth or perhaps the fifteenth of this month.” He asked Oriani to supply him with his most recent observations to carry across the frontier to Lalande. For his part, Méchain appended a gift offering, one of those gifts by which a savant elicits the free concession of scientific information from another: a summary of his own astronomical findings in Catalonia, including various eclipses, various stars, and a summary of the latitude data for Barcelona.
Oriani’s response was to rush down from Milan to visit Méchain before he left Italy. In honor of this visit, the Frenchman retrieved one of his repeating circles from the depot (even as Tranchot was packing their trunks) to demonstrate its marvelous capacities. They set up the apparatus on the terrace of the Hôtel du Grand Cerf—“one of the best hotels in town, magnificently situated right across from the sea”—and together took latitude measurements through the mid-October nights.
Oriani fell in love with the circle, and when his colleagues in Milan learned of its capabilities, they were eager to procure one of these marvels for themselves. The Milanese had been conducting their own geodetic survey, and Oriani suggested that he and Méchain connect the French and Italian grids via Genoa. “It is desirable that so beautiful an enterprise be undertaken.” Méchain wrote to Calon for his approval. To Méchain’s surprise Calon not only seconded the project, he even promised the Milanese a repeating circle of their own as soon as Lenoir could fashion one. The project would, after all, link the maps of France and Italy just as the French army was closing in on Turin to the immediate north. But there was to be no reprieve for Méchain; Calon still insisted that he report to Paris. “For you are not destined to return to Italy, but to extend the measure of the meridian in concert with Delambre.”
So Méchain concocted another plan to justify his sojourn in Genoa. (Never underestimate the ability of a scientist to generate new and interesting scientific questions when the need arises.) As Méchain pointed out, Genoa was near the 45-degree parallel, halfway between the equator and the pole. Bordeaux was not the only site suitable for a pendulum experiment to determine the length of the meter. If Calon would just send him the Observatory’s platinum-bob pendulum, Méchain would save the Commission the trouble of transporting a scientific team to Bordeaux. Or, alternatively, he might conduct observations at Genoa to supply new refraction corrections (and secretly resolve the discrepancy in his own Barcelona data).
In the end, the new French ambassador rescued Méchain by taking matters out of his hands. In a month on the job, Ambassador Villars had become familiar with Méchain’s vacillating ways, and Méchain had come to consider Villars “a friend of the arts and sciences.” The ambassador certainly proved a good friend to Méchain. Villars was savvy in the ways of officialdom. He advised Méchain to request further instructions from Paris—no one could ever fault a public servant for seeking to clarify his orders—and in the interim he would refuse to issue Méchain a passport, thereby taking responsibility for the delay upon his own head. All Méchain had to do was to write the request. On Monday morning, Villars told him that he expected the official request by two that afternoon, before the mail boat set out. When Méchain arrived at the post office at half past three—“I was still hesitating,” he admitted to Slop—the outgoing mail was already in the satchel, and Villars and the carrier were waiting impatiently. Villars snatched the letter out of Méchain’s hand and stuffed it in the satchel. “Your shilly-shallying is futile,” he told Méchain. “Your worries have no basis. Calm yourself and spend the rest of the afternoon with me.”
Villars’ maneuver worked. Tranchot stopped packing. And Méchain spent the rest of the winter on the Italian Riviera. “Our ambassador here,” he informed Oriani, “has required me to defer my departure.” In the meantime, he even took in some theater. While his traveling companions favored melodrama, Méchain preferred the classical theater, in which “order and tranquility reign, virtue is honored, and the happiness of all is every day more assured.” Some days, he even felt a degree of calm in his heart, only to suffer horrible presentiments of ruin at night. Folded inside a letter to Slop, he slipped a note labeled “For your eyes only.” “I do not believe I have given any cause for reproach,” he wrote, “but in the present circumstances, who can be sure he is safe from reproach, envy, enmity, and jealousy?” He had heard rumors that his enemies in Paris were conspiring to thwart his plans—although his wife seemed to be shielding him from these intrigues. “You see that I am well informed about events six hundred miles away and that my fears are not all chimeras.”
Today we have our own clinical terms for such psychological states. Méchain was depressive, we would say; he was paranoid, obsessive, passive-aggressive. No doubt this is true. Yet even feelings have their history, and Méchain was a man of the eighteenth century, a man who suffered from the exquisite malady known as melancholy. Melancholy was a complex affliction fueled by a disequilibrium of body and mind. It preyed on solitude and could encompass many moods. A voluptuous melancholy delighted in tombs and barren landscapes; nothing could be more delightful for an elegiac poet. A bitter misanthropic melancholy, such as beset Candide when he encountered the world’s cruelty, extinguished all hope in the future. And an anguished melancholy, oppressed by regrets too great to bear, might drive the mind to madness, or suicide.
Méchain exhibited all the melancholic symptoms featured in the nosology of Doctor Philippe Pinel, director at the Bicêtre asylum and Méchain’s colleague at the Academy: taciturnity, gloomy suspicion, monomania, and love of solitude. But if Méchain suffered from paralyzing doubt, it was because he faced an awful dilemma. If he trusted no one, it was because he did not trust himself. If he worried about conspiracies, it was because he was himself keeping a secret.
That winter, Méchain did not conduct the pendulum experiment. Nor did he measure geodetic triangles with the Milanese. A nameless colleague back in Paris was preventing Calon from sending him the pendulum, or so Méchain believed. As for the triangles linking Italy and France, Lenoir had yet to fashion another circle. At least Méchain had a neat solution for the latter problem. He asked Calon if he might sell one of his own circles to Oriani and take Lenoir’s new circle when it was ready. This would equip his team with hard currency and obviate the need t
o transport the circle home. To his surprise Calon again approved, and a week later Méchain was able to offer Oriani his choice of repeating circles: the one ruled in the traditional 360-degree scale, or the one ruled in the new 400-degree scale. Oriani chose the 360-degree circle and the two savants settled, somewhat awkwardly, on a price of 1,200 livres.
Méchain did conduct a few astronomical observations that winter from the bell tower of San Lorenzo cathedral, and at the famous Lanterna. One purpose of these observations was to test his conjecture about the refraction correction. The results were inconclusive. He also learned that Oriani intended to publish his Barcelona results, despite Méchain’s warning that they did not seem to follow the usual rule of refraction.
In late December Esteveny, the instrument-maker, decided to return to his family and business in Paris via the mail boat to Nice. The voyage was a month-long fiasco. A sudden storm forced all the passengers to toss their belongings into the sea, and Esteveny arrived in France with only the shirt on his back. Then, as he disembarked, the French authorities arrested him as a returning émigré. Freed on the say-so of the captain, he was hampered at every stage of his overland trip by a lack of hard currency. When reports of his unhappy voyage filtered back to Méchain, it only confirmed the latter in his caution. Just imagine what would have happened had Méchain entrusted Esteveny with his precious instruments, or worse, with his irreplaceable data!
Méchain still had Tranchot, though the two men had grown increasingly estranged. They no longer lodged at the same inn, nor spent time in one another’s company. Both men came from the lower strata of the Ancien Régime, yet neither had found his place in the new. Tranchot was a military engineer, a man of action, robust and confident. He was a bachelor who had yet to draw upon his expedition salary. He wrote short frank letters in a neat square hand. Yet he aspired to the trappings of polite society. During his twenty years in Corsica, he had amassed a small collection of minerals and fossils, and during his sojourn in Italy he added petrified fish, feldspar, and crystals “very sought after by connoisseurs in Paris.”
Each man operated according to his own exacting conscience. Tranchot had his military patriotism and Méchain his passionate rectitude. Perhaps this was why they found one another so exasperating. Tranchot considered Méchain’s delays a dereliction of duty, and his vacillation pathetic. When Méchain announced for the umpteenth time that they would soon be leaving Genoa, the engineer wryly commented, “According to Monsieur Méchain we will be leaving after Easter, but I don’t yet know if that is really true.”
For his part, Méchain swore he bore no enmity toward his adjutant, despite his suspicion that Tranchot was plotting to usurp his leadership. Tranchot’s impatience was a continual reproach, his competence a continual challenge.
[G]iven what I have seen since our departure from Barcelona, I would be deluding myself to count any longer on his friendship, affection, or trust. Since arriving here he has expressed himself all too clearly, and I am not so stupid as to expect any resumption of his previous feelings. But honesty and probity have always been my rules of conduct with him, as with others.
Yet Méchain had to wonder whether Tranchot knew his secret. And whether he might give it away.
As spring approached, and the season for geodetic campaigning drew near, Calon tried again to lure Méchain back to France. He tried to make the prospect appealing to Méchain’s honor. Many of France’s most illustrious savants had signed onto his new geographic enterprise, he noted: Lalande, Delambre, Laplace, all his old colleagues. “You will not find yourself a stranger in the presence of those who share your labor,” he said—not realizing, of course, that these were the very people Méchain feared would unmask his error.
Not until the law of 18 germinal III (April 7, 1795) formally revived the meridian survey and restored Delambre to the mission did Méchain pack in earnest to leave Genoa—though even at this last minute he claimed intrigues in the capital jeopardized the expedition. Again he began making excuses not to return. This time, however, he could no longer postpone his departure. To fail to leave now would cost him his position and his family’s sole means of support. In his last letter to Slop he even summoned a stoic courage: “But the die is cast, and I will attempt the adventure.” In late April, he boarded the mail boat for Marseille with his one remaining circle and his one remaining assistant.
Even as Méchain left Genoa, the Revolutionary Republic moved against the patrician city. Tranchot had been tracking the war’s progress. In November, he boasted of French victories that would oblige the enemy to recognize the sovereignty of the French people. Nearer to Genoa, plans were afoot to land 20,000 French soldiers behind Austrian lines. In mid-March, Tranchot climbed the hills above town to watch the French fleet engage the English navy. The guns sounded from four in the morning until three-thirty in the afternoon, and Tranchot initially reported a French victory, one which he hoped would oblige the Genovese patricians to abandon their cowardly neutrality. Then, when he discovered that the battle had actually forced the French to retreat to Toulon, he dismissed this as yet another betrayal of France from within. Oh when, Tranchot wondered, would France find a hero to right its reversals?
Within a year Bonaparte led his armies across Italy in one of the most dramatic military campaigns of modern history. In April 1796 his army occupied Genoa, the city he had judged ripe for the picking during his visit of 1794. In May 1796 Milan opened its gates to the conqueror, only to have the city pillaged by French troops—though Napoleon assured the astronomer Oriani that men of science would gain from his conquest: “All men of genius, all those who have achieved distinction in the Republic of Science, are French, no matter what their native land.” In June 1796, French troops occupied Livorno and Pisa, where Slop’s son went to work as an agent of the French Republic.
When Méchain and Tranchot arrived in Marseille by mail boat in the spring of 1795, Méchain’s colleagues had every reason to think he would proceed immediately to Paris to consult with them before resuming his mission. Paris was only a week’s ride north by carriage. Or perhaps he would prefer to head directly to Perpignan to pick up his triangulations where he had left off. Perpignan was only a few days’ ride to the west. Yet Méchain holed up at Marseille for the next five months. During those summer months, the best season for geodetic observations, Delambre measured the entire sector from Orléans to Bourges.
Méchain’s dithering infuriated Tranchot, exasperated Calon, and baffled his colleagues. To prompt him to resume the mission, Calon sent Esteveny down to rejoin him in Marseille, as well as two new assistants to replace Tranchot. The French army was desperate for surveyors, and Tranchot was one of the nation’s most experienced military cartographers. Calon wanted him to triangulate the mountainous frontier along the Swiss-Italian border, where Napoleon was preparing his invasion.
Privately, Méchain admitted that Tranchot no longer wished to serve under him. “I know he does not want to be under my direct authority, and may God grant his wish!” Yet he did not want to forgo Tranchot’s services either. Nor can he have been eager to have his assistant—the one person on earth who might have guessed his secret—far out of sight. So when his new assistants arrived in Marseille, he refused to release the engineer. He wrote to Lalande that Calon wanted to deprive him of his most capable aide. “We got on well together while on mission; he assisted me marvelously in my astronomical observations.” He wrote to Delambre that without Tranchot his progress would be slow. Admittedly, a second observer might seem superfluous now that he had only one repeating circle. But Calon himself had approved the sale of the other circle to the Milanese, and it was not Méchain’s fault that Lenoir had yet to supply a replacement. In mid-August, Calon relented. “I must at last defer to your wish that I not separate you and Tranchot. You may use him as you judge most convenient.”
This suited Méchain. With Tranchot under his direct authority, and with only one circle available, he controlled both the observations and t
he data.
Tranchot, however, could hardly have been more disappointed. Instead of commanding his own survey, he was once again under the authority of the vacillating, exasperating savant. He obeyed Calon’s orders—it was wartime and he was an officer—but he insisted that the expedition get underway. He requested permission to rent a coach and driver at 10 francs a day to carry the team overland to Perpignan. Yet, after approving this plan, Méchain balked at boarding the carriage and instead booked a passage on a naval vessel traveling to the port of Sette. (Four years later, their expedition done, the driver of the Marseille coach turned up in Paris with the signed contract to collect his 15,000 francs in accumulated daily fees, and Delambre was obliged to bargain his bill down to the cost of a new coach instead.) In late August 1795, Méchain and his team sailed from Marseille to the port of Sette. From Sette the team was rowed in longboats onto the beach at Canet. And from there soldiers were commandeered to haul their equipment four miles across the flatlands to Perpignan. After a hiatus of two and a half years, Méchain had at last resumed the measurement of the meridian.
CHAPTER SEVEN
Convergence
And every Space that a Man views around his dwelling-place Standing on his own roof, or in his garden on a mount Of twenty-five cubits in height, such space is his Universe: And on its verge the Sun rises & sets, the Clouds bow To meet the flat Earth & the Sea in such an order’d Space: The Starry heavens reach no further but here bend and set On all sides & the two Poles turn on their valves of gold; And if he move his dwelling-place, his heavens also move Where’er he goes, & all his neighbourhood bewail his loss. Such are the Spaces called Earth & such its dimension.