Passionate Minds

by David Bodanis

  It was the sort of genius that has arisen only a very few times in human history—but Newton didn't publish what he'd found. He knew that what he kept secret could never be criticized by anyone else. When the plague ended and he returned to Cambridge, he seems to have told almost no one of what he now knew. For decades he became immersed in secret worlds: alchemy, biblical interpretation, and discovering the truth about Solomon's ancient temple, scribbling his results in volume after volume of cryptic notes.

  What inspired him to finally publish his early science results was the realization, almost two decades later, that other researchers were beginning to touch on a few of the results he'd uncovered on his mother's farm. He loved secrecy, but he also loved acclaim: not petty academic acclaim, but the awe that being known for coming closer than any other mortal to uncovering God's plans could inspire. In a quick, two-year burst, he began writing up what he knew, in the enormous, impressive folio volumes that he labeled his Principia.

  To Voltaire and most others, the Principia was a great storehouse from which to pluck useful results: that apples fell to the ground at particular speeds, that planets orbited following certain rules. But why did this happen? That was the question Emilie had become fascinated with from her several years' excursion into Leibniz, and she believed that Newton had intentionally hidden the answers away deep within his convoluted text. What was the true reason—what had he been puzzling over?— that he'd felt obliged to wait twenty years before writing up what he'd seen? And then, why had he presented it through elaborate, old-style geometry when he clearly had the skill to present it more directly, using the modern tools of calculus (which he himself had invented)?

  Emilie knew, from her readings of biblical commentaries, that there was a great tradition of hidden writing, in which mystics, prophets, or others who felt they had access to powerful knowledge presented their findings to be read in two ways. There would be a surface interpretation, which ordinary readers or listeners would grasp, but there would also be a deeper level, hidden away.

  Newton lusted for immortality—or at least for understanding how God's universe could be immortal. For seventy years people had read his Principia but missed these deeper findings. Emilie was convinced she could unearth them amidst the immense range of theorems in the thick Principia volumes. By revealing the right ones, it would be as if she could see through a portal.

  She could, in what might be these last months of her life, glimpse what it would be like to survive forever.

  That was what she had been doing in Paris once she'd collected the books she'd left, and made contact again with key researchers she knew from the Academy of Sciences. Her previous achievements weren't enough: the essays, books, and fame, the skills at languages and mathematics and everything else. She needed this deeper work—but there wasn't much time. “I lost a year in Lorraine,” she wrote to her mathematician colleagues Father Jacquier and Johann Bernoulli, “where it was impossible to work…. I'm here to finish my Newton. I won't leave until it's done.”

  The bulk of the direct translation was already complete—she'd managed that even before the Sceaux escapade and the trips to Lunéville. But that wasn't what counted. Now, in her limited time, she made sure she didn't miss the two central groups of theorems in Newton's work.

  Voltaire had simply accepted that apples and moons and everything else tumble down, falling at a predictable rate. Emilie, however, was hunting through Newton's vast text to find the seemingly casual theorems where he tried to work out how gravity stretched up, shooting from the very center of the Earth and going outward.

  The answer was in the theorems that Newton had numbered 70 through 75. In the complicated geometrical form in which Newton had presented them, their significance was hard to see. Emilie translated the ideas behind them into more modern, transparent language: showing how the Earth, Sun, or any other body could be imagined as divided like an onion into one slender inner layer wrapped around another. She went through the analysis of how those layers would affect each other—all the rock or magma or whatever else might exist for the thousands of miles beneath our feet—and confirmed the wondrous conclusion that the entire bulk of a planet or star acted as if its huge mass wasn't spread out at all.

  As a result, it was possible to treat the whole planet as a single mathematical point, suspended in an empty cage, right at the center of our globe. It was from that single point that the ruler of the universe had arranged matters for the streaming gravitational force to emerge.

  The other group of theorems she made a point to bring out were—to use modern terminology—the ones on the conservation of energy. She'd struggled with that in her own work following on from her fire experiments; she'd also engaged in lengthy public debates with senior researchers at the Academy of Sciences about what it meant.

  But the deepest answer was already in Newton—if one just knew how to look.

  The seemingly minor corollary 40, attached to theorem 13, was where it was hidden. There had been hints of that in Leibniz's work too, but Emilie wanted to go further in showing exactly what the idea meant, and thus guide her successors for their research to come. Somewhere in there might also be the answer to all her questions about free will: about why she'd had to go to Lunéville and take up with SaintLambert; about what would happen to Cirey, centuries in the future, after she and everyone she knew was gone.

  From the time she'd been a little girl at her father's table, she'd wondered what the future would make of us. With this task, she could get a glimpse. She was confident now. Her work was important, and her life could be a success.

  All she needed was time. Emilie was about four months pregnant when she accepted Stanislas's offer to stay at the Trianon palace. In the quiet rooms there, she started driving herself even harder than she had before. She stopped seeing other friends, and aside from a coffee break around 3p.m. would work all day, only stopping for a single meal around 10 p.m. She'd chat with Stanislas over dinner, or Voltaire if he was visiting from Paris, but when Stanislas went to bed, or Voltaire withdrew for political machinations, she'd return, candles lit, to her writing for hours more.

  George Bernard Shaw once said that for someone who didn't comprehend the music of Bach, it sounded as tedious as the empty clacking of an industrial sewing machine with no fabric going through it. But once you understood the music, you saw the beautiful multicolored tapestry being poured out. Voltaire couldn't follow Emilie's mathematical symbols and begged her to start going to sleep earlier. He told her it was bad for her to stay up so late—increasingly till 3 or 4a.m.—but she shrugged him off. How important was her health, anyway, if her notion that she wasn't going to survive the labor were to come true? In her old manuscript “Happiness” she'd written: “It's rare to admit it, but we all secretly like the idea of being talked about after our death. In fact, it's a belief we need.” This is what she was desperate to ensure now.

  She kept up her work pace during that strange Paris summer. The weather was odd, sometimes unseasonably cold, with driving rain under gray skies, then abrupt, humid, thick air. Her son was angry at her, embarrassed by her being pregnant at her age. Voltaire was more and more tense. The reformist minister Machault, who was trying to get the king to push for even a minimum general tax on the wealthiest groups in society, was being blocked. At one point, when Voltaire was attending a play of his own at the Comédie Française, he started screaming at the crowd. There hadn't been a professional claque acting against him. It was just a few ordinary theatergoers, laughing more loudly than he wished. His rage was so extreme that they went quiet.

  By June, Stanislas had to leave for Lunéville, and it would be hard for Emilie to remain at the Trianon without him. She moved back to Paris, but it was getting too uncomfortable to stay there. The police were on edge, for the recent peace treaty with Austria was leading to the appearance of large numbers of unemployed veterans on the Paris streets; there were religious mobs crowding in ominous numbers. Roundups of popular religious lea
ders and radical thinkers were under way. It was time to take up Stanislas's offer and follow him to Lorraine. Saint-Lambert was still mostly withdrawn, but just occasionally his letters were warm. Emilie kept on writing to him, desperate for companionship (“I feel an emptiness that I would love you to fill”), even though she knew he couldn't really be trusted.

  Voltaire was coming with her. He knew that no one had ever understood him as she had; if the worst happened, no one would ever understand him in that way again. “These links have lasted a lifetime,” he wrote. “How could I possibly break them?”

  Late in June they all got in the carriage again, Voltaire and Emilie and her maid—and this time all the manuscripts she was working on packed tight with them. Longchamp again had to ride a certain distance ahead, and although he clearly wouldn't have minded traveling in safe daylight, “it was the wish of Madame that we travel in these nocturnal hours. Her reason, she informed me, was that since there is always time lost during a voyage, it was better that this be a portion of one's sleep, rather than to lose time in which one might work.”

  They stopped at Cirey for a few weeks, and there she worked even longer hours, settling in for work sessions after late dinners and coffee, and continuing them almost till dawn, just as she'd done during her fire experiments years before. Voltaire couldn't get her to slow down: “She believed that death was striking,” he wrote, and “… all she thought about was how to use the little time she had left, to deprive death of taking what she felt was the best part of herself.”

  At Lunéville Stanislas had prepared a summer guest house for her, even painting it a gentle blue inside. (Charles Stuart was another guest in Lunéville that summer, for after his failure in Scotland he'd ended up expelled from France—and Stanislas had a great understanding of the plight of monarchs who lacked a country.)

  Saint-Lambert was kind to Emilie at first, helping her walk around the grounds, but it didn't last long. After one dreadful dinner she quickly wrote him: “My God, you treated me cruelly, you didn't glance my way once. I was used to looking in your eyes and seeing how much you cared for me, how much you loved me. I looked tonight, and didn't find anything…. I bitterly repent for having been seduced by your love; for once having believed your feelings matched mine.”

  There were still calculations for the Newton project to finish off, but she also began speaking confidentially to Longchamp, asking him to help put her private papers in order. “Lunéville had the most excellent facilities for Madame's health… yet she approached me with various sealed envelopes, and made me promise that, if she were not to survive the dangers she was soon to face, I was to execute her instructions with complete accuracy.”

  Saint-Lambert, now in full cowardice, had found reason to leave Lunéville and serve at his garrison in Nancy. Late in August she wrote asking him to see her one more time. Voltaire never left her, and although not disparaging her fears, he assured her—for who would know as well as he how amazingly one's greatest health worries can be false?—that she really did have a good chance of surviving. She was fit; the pregnancy had advanced with no complications; Lunéville was clean and the air was fresh.

  He might well be right. In the direct translation portion of her work, she'd written out Newton's words: “The admirable arrangement of the sun, the planets, and the comets can only be the work of an allpowerful and wise being.” Not everyone her age failed to survive childbirth. If there was any justice, shouldn't she be one of the fortunate ones?

  Sometimes the uncertainty was too much (“I'm terrified when I think my premonitions might be true”). But she continued her intense writing schedule and did manage to finish the manuscript, on August 30. She wrote to the director of the King's Library that her pages were on the way: “It would be most kind to…have them registered so that they can't get lost. Mr. de Voltaire, who is here beside me sends you his tenderest compliments.” In her final letter, dated August 31, 1749, she was tired, but still had hope:

  I walked to my little summer house today, and my stomach is so swollen, and my back so sore, that I wouldn't be surprised if I had the baby tonight.

  Emilie du Châtelet gave birth on the night of September 3. She died on September 10 of infection stemming from the labor; the child— a girl—died soon after. Her translation and commentary on Newton's Principia became fundamental to key eighteenth-century developments in theoretical physics, laying the groundwork for much of contemporary science.

  Voltaire was bereft: “I've lost the half of myself—a soul for which mine was made.” Months later, after Voltaire had abandoned Cirey and moved back to Paris, Longchamp would find him wandering at night in the apartments he'd shared with Emilie, plaintively calling her name in the dark.

  I shall await you

  quietly

  In my meridian

  in the fields of Cirey

  Watching one star only

  Watching my Emilie.

  —V, “Ode”

  What Followed

  Emilie's great work, Principes mathématiques de la philosophie naturelle de Newton, traduits du latin par Mme du Châtelet, was published ten years after her death, when the return of Halley's comet in 1759 stimulated a burst of interest in Newtonian mechanics. The key notion she brought out and elaborated from Newton proved to be as important as she'd hoped. This was the new concept of “energy,” which showed that there was a total amount of movement in the world, and although the way it was arranged could fluctuate wildly—there could be cities that rose up and took dominion over others; there could be civilizations that were broken apart, and their inhabitants dispersed—despite all those shifts, that total amount would never change. Just as she'd hoped, it was a proof that nothing ever fully disappears, that nothing ever dies.

  More technical aspects of her work played a great role in energizing the French school of theoretical physics, associated with Lagrange and Laplace, whose formal achievements (the Lagrangian and Laplacian stability calculations) ended up as fundamental working tools in subsequent science, from Faraday and Maxwell's field theory of the nineteenth century to quantum theory and relativity in the twentieth. English researchers, lacking the advantage of seeing Newton's work clearly brought out with Emilie's more modernized notation, stuck to Newton's cumbersome original forms, which slowed their progress for over two generations.

  Emilie's role in focusing and spreading the political ideals of the Enlightenment continued to the end. In 1748 she'd carefully helped an obscure Parisian investigator with questions he'd had about the equations for the air resistance faced by a moving pendulum. The following year, he hesitantly sent her a long essay he'd written on the origins of morality. Her thoughtful, encouraging reply was what the author—it was Denis Diderot—termed one of the “two sweet moments” of his life.

  When Diderot was imprisoned in the fortress of Vincennes for this essay, in July 1749, Emilie interrupted her own writing to use family connections to ensure that he was treated well, even though she was almost eight months pregnant. After his release, Diderot went on to be the main developer of the grand, twenty-eight-volume Encyclopédie, which built on Cirey's approach of sharing and analyzing all knowledge, extending it for the next generation.

  At the time of Emilie's death, Voltaire's greatest work—Candide— was still before him. Its themes of optimism versus pessimism and whether God intervenes in our life had been at the heart of his discussions with Emilie. Her abrupt death made its cynical conclusions impossible for Voltaire to resist; yet the model of their earlier years together—sharing a life with this vigorous, brilliant woman—was behind his constant calls for liberty and freedom of opinion, which were important not just in the ideas leading to the American Bill of Rights, but also in the intellectual case for feminism, as developed by Mary Wollstonecraft and then others in generations to come.

  Voltaire left France a year after Emilie's death, moving to Berlin, where he was abortively involved with Frederick's planned Berlin Academy of Sciences. In 1758, at age six
ty-four, he settled in the small town of Ferney, just across from Geneva, yet inside the French border. He lived there for twenty years, publishing Candide and other works, leading public intervention against cases of religious persecution, and encouraging Diderot and others associated with the vast progressive Encyclopédie project.

  Visitors came by when Voltaire was very old:

  I sent in to enquire whether a stranger might be allowed to see Voltaire's house & was answered in the affirmative. The servant conducted me into the cabinet… where his master had just been writing. I should have said that close to the chapel…is the theater that [Voltaire] built some years ago, but which he uses only as a receptacle for wood and lumber, there having been no play acted in it these 4 years.

  …When the weather is favorable he takes an airing in his coach, with his niece, or with some of his guests. Sometimes he saunters in his garden; or if the weather does not permit he employs his leisure hours in playing at chess with Father Adam, or in dictating and reading letters, for he still retains correspondents in all the countries of Europe, who inform him of every remarkable occurrence, and send him every new literary production as soon as possible.

  … Seeing me…[Voltaire] approached the place where I stood. It is not easy to conceive it possible for life to subsist in a form so nearly composed of mere skin and bone, as that of M. de Voltaire. He complained of decrepitude, and said he supposed I was curious to form an idea of the figure of one walking after death.

  However, though emaciated, his eyes are still full of fire, and a more lively expression cannot be imagined. He enquired after English news, and what poets we had now…. Said he: you seem to have no one [anymore] who lords it over the rest like Dryden, Pope and Swift.