Émilie du Châtelet

1706-1749

When I add the sum total of my graces, I confess I am inferior to no one.

Émilie du Châtelet was regarded as one of the most beautiful and brilliant women of the Enlightenment, even by her enemies; but for more than two centuries she was better known for being Voltaire’s mistress. “Judge me for my own merits,” she once protested. “Do not look upon me as a mere appendage to this general or that renowned scholar.” Few women of the period could write, much less conduct experiments in physics, chemistry, and mathematics, compose poetry, and translate Greek and Roman authors into French with ease as she did. Her work contributed to energizing the school of theoretical physics in France. She would have been extraordinary in any era, let alone the one she was born in. In her lifetime, she fought for the education and publication that she craved, but struggled under the burdens of society’s expectations for women of her class.

Gabrielle-Émilie Le Tonnelier de Breteuil grew up in the lap of luxury surrounded by servants in a three-story town house near the Tuileries gardens. She was doted on by her father, who encouraged her in her studies, refusing to let her mother send her to a convent. He made sure that she had the same education as her brothers, including fencing and riding lessons along with Latin, Italian, Greek, and German. She was so precocious that her father enjoyed showing her off to his intellectual friends. Her mother despaired at having such an unnatural daughter who refused to appreciate proper etiquette. But Émilie had a hunger for learning that just couldn’t be quenched with talk of fashion and gossip. When her father’s income shrank, and there was no money for new books, Émilie used her mathematical skills at the gaming tables to get her fix.

Tall and clumsy as a child, Émilie seemed destined for spinsterhood. Her father worried that “no great lord will marry a woman who is seen reading every day.” But suddenly at the age of fifteen, she grew from an ugly duckling into a swan. Although she was almost a giant at five foot nine in era when even most men were an average height of five foot six, she was also blond with a supermodel figure and a face that could launch a thousand ships. Raised away from court, Émilie took joyous delight in everything, and soon bets were being made by the court rakes to see who could seduce her first. Émilie nipped that idea in the bud the day she verbally fenced with a colonel with consummate skill. This display of her rapier wit served to keep the rest at bay. They soon turned their attentions elsewhere.

Émilie went husband hunting with a vengeance. She had a laundry list of requirements: he had to be older, of higher rank, and he had to be content that she was beautiful and bright since her dowry was pathetic. She found him in the marquis Florent-Claude du Chastellet,⁴ who was twelve years older, a career soldier from one of the oldest families in Lorraine, who preferred wars to court. Out of all of her suitors, he was the only one that Émilie felt she could tolerate. The marquis promised not to interfere with her studies, and Émilie promised to turn a blind eye to his infidelities. They were married on June 25, 1725, at Notre Dame. The story goes that the bride halted the ceremony to correct the clergyman’s pronunciation of a Latin phrase.

After bearing three children, Émilie was bored out of her mind. She moved to Paris to pursue her studies further while her husband stayed in the country. She hired the best tutors in math and physics from the Sorbonne, studying like a fiend. Since women weren’t allowed at Gradot’s, the “in” coffee shop for the scientific crowd, Émilie donned breeches and a frock coat to talk shop with her peers. The proprietors pretended they didn’t notice. Émilie still made time for high society, but she did it her way, dripping in diamonds and wearing gowns of gold and silver cloth, normally reserved for royalty, that were cut low enough to show off rouged nipples. She chatted happily about Descartes to her throngs of admirers. She held a salon in her newly renovated town house, decorated tastefully but expensively. When she ran out of money for the renovations, she gambled until she’d won enough to continue.

Once she’d given her husband an heir, Émilie indulged herself in a love affair with the duc de Richelieu.⁵ The duke was rich, powerful, and extremely handsome; men wanted to be him, and women threw themselves at his feet. Émilie was a different kettle of fish. He fell for her because he liked to talk to her. She was witty and chattered a mile a minute about the things she loved, mainly science and the theories of John Locke. The affair didn’t last long, as the duke couldn’t be faithful to anyone, and the very qualities that made Émilie different began to pall after a while. Still, they managed to end their affair with dignity and remain friends.

Émilie yearned for a man who could satisfy her both intellectually and sexually. She found him in Voltaire. They were introduced by mutual friends in 1733 after Voltaire’s return from a long exile in England. Already he was famous for his plays and poems and his ability to get into trouble. It was the coming together of two geniuses who defied social conventions. They were immediately attracted to each other and became lovers soon after they met. “Why did you reach me so late? What happened to my life before? I hunted for love but found only mirages,” he wrote to her. They broke the conventionally accepted rules of adultery, showing their affection in public, romping indiscreetly all over the city.

They made an odd couple. Not only was Émilie a head taller than her lover but she was twenty-six and Voltaire was thirty-nine. Voltaire had finally found a woman who was intellectually his equal, although his superior in rank, and who respected and adored him. Émilie finally had a man who respected her brain as well as her body. He was also one of the few men rich enough to afford her expensive tastes. Voltaire taught her how to speak English so that they could converse without anyone understanding what they were talking about. She read his work and gave him gentle criticisms.

Not long after they met, they moved into the Château Cirey, a tumbledown mansion owned by Émilie’s husband in the country between Champagne and Lorraine. The move was precipitated by Voltaire getting into trouble again for his radical political views. For the next fifteen years, they lived there together, embroiled in a private world of intense intellectual activity intertwined with romance. Émilie described their life at Cirey as “Paradise on Earth.” Voltaire lent the marquis forty thousand francs to pay for renovations to make the château livable, including a tub for Émilie’s daily baths. Playing architect, Émilie installed a kitchen inside the château, a novel idea at the time. They quickly amassed a library of twenty-one thousand volumes, more than in most universities in Europe. The marquis was happy with the renovations because the restored house gave him a place to hunt. His visits also gave their affair an aura of respectability. The marquis was not a jealous man. Since Émilie had no objections to his affairs, he refused to meddle in hers.

The château became something like a modern-day think tank. Émilie and Voltaire entertained some of the best minds from Paris, Basel, and Italy, including her former lover Pierre Maupertuis, Francesco Algarotti, and Clairaut, hailed as France’s new Isaac Newton, who at first came to scoff, but then hung around, impressed by what they saw. Visitors to the château were only entertained in the evenings since Émilie typically put in twelve to fourteen hours a day at her work. She had taken over the great hall as a physics lab, testing Newton’s theories with wooden balls hanging from the rafters. Eventually the hall became so cluttered that it was an impenetrable maze. Émilie had prodigious energy, often sleeping only three or four hours a night. When she was on a deadline, she plunged her hands into bowls of cold water to stay awake.

Rooms were dimly lit and the curtains were shut, the better for mental stimulation. Guests were expected to entertain themselves. Dinner was at no set time, just when Émilie and Voltaire decided they were hungry. Émilie would arrive at the dining room table powdered and perfumed and dressed as if at a court ball, dripping in diamonds, her fingers stained with ink. Guests served themselves from the dumbwaiters. Conversation was fast and furious as the lovers discussed what they were working on or argued mathematical equations. After dinner it was back to work. Late at night, they would put on plays in the little theater or Émilie would play the pianoforte and sing entire operas. There would be poetry readings at 4:00 a.m. or picnics in the middle of winter.

Émilie and Voltaire decided to collaborate on a major project: a treatise on the works of Newton, covering the entire spectrum of his philosophical, scientific, and mathematical studies. When word first leaked, all of Paris ridiculed the idea. But when it was finally published after two years of work, Émilie had the last laugh. It was hailed as a masterpiece by every scientist of note. Although Voltaire’s name was on the cover, he acknowledged her as coauthor. She was recognized as a woman of powerful intellect and finally treated with the respect that was due her. The Elements of Newton’s Philosophy was so influential that it persuaded the French to abandon the theories of their national hero, René Descartes, and jump on the Newton bandwagon.

Now Émilie made the most unorthodox decision of her life: to submit an essay to the Royal Academy of Sciences yearly competition. This year the theme was fire. Émilie had been helping Voltaire with his essay but she felt that his conclusions were wrong. Her thesis was that light and heat were the same element while Voltaire believed the opposite. She had an unfair advantage since she knew what Voltaire had written. In two weeks she wrote her essay, 139 pages long. She didn’t tell Voltaire that she was entering, although she did tell her husband; she needed his permission to enter. She submitted her entry anonymously, wanting it to be judged on its own merits. Neither Voltaire nor Émilie won, but he later persuaded the academy to publish her paper under her own name. It was the first time the academy had ever published a dissertation by a woman.

In her spare time, when she wasn’t conducting science experiments or learning advanced calculus, Émilie wrote poetry, translated Latin and Greek classics, and mastered law to defend her husband’s interests at court. For fun, she wrote one of the first self-help books, entitled Discourse on Happiness, which went through six editions. In it, Émilie taught women how to be as happy as she was. She advised them to cultivate “strong passions,” enjoy sex, enrich their minds through education, and make themselves mistresses of the “metaphysics of love.” Émilie translated the book into English herself and it was also translated into Dutch and Swedish.

But the idyll couldn’t last. Voltaire fell out of love first. It was hard living with a genius, particularly one who was almost always right. He had taken up history and given up science, realizing that Émilie was far ahead of him intellectually in that field. “I used to teach myself with you,” he wrote, “but now you have flown up where I can no longer follow.” Émilie grew tired of having to tend to his ego, when she wanted to do her own research; and she became upset over the time Voltaire spent at the court of Frederick the Great of Prussia, whom she didn’t like or trust. They both found solace in other lovers. Voltaire secretly began having an affair with his widowed niece Madame St. Denis. Émilie fell in love with the poet and soldier Jean François de Saint-Lambert, who was ten years younger. Their relationship eventually dwindled into a loving friendship. Although no longer lovers, they couldn’t do without one another. No one understood them as well as each other.

At the age of forty-two, she found herself inconveniently pregnant. The relationship with Saint-Lambert petered out at the news. Voltaire, however, stayed by her side and her husband graciously offered to accept paternity. In a letter to a friend she confided her fears that, because of her age, she would not survive her confinement. During her pregnancy she moved into a suite at Versailles, where she redoubled her efforts to finish her book on Newton’s Principles of Mathematics, staying up until the wee hours of the morning. She finished the book a few days before she went into labor in September. Émilie bore the child, but died six days later from an embolism. The child, a daughter, soon died as well.

Voltaire was distraught: “I’ve lost the half of myself—a soul for which mine was made.” Months after her death, his servant Longchamps would find him wandering through the apartments that he had once shared with Émilie in Paris, plaintively calling her name in the dark. He helped to prepare Émilie’s book, called The Principles of Mathematics and Natural Sciences of Newton, for publication. It came out ten years after her death, just in time for the return of Halley’s comet, which stimulated a burst of interest in Newton. To this day it is still considered to be the standard translation of Newton in French, a lasting testament to the woman Voltaire described as “a great man whose only fault was being a woman.”

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