The life of Emilie de Breteuil, Marquise du Châtelet was surprising in many ways. Born into 18th century French nobility, her name has been linked with the work of Leibniz, Newton, Maupertius, Koenig, and Voltaire. Emilie lived but 43 years. Looking back, one of the most notable features of her extraordinary life was how natural it seemed for her.
Gabrielle-Emilie Le Tonnelier de Breteuil was born in Paris on December 17, 1706. Education of girls at that time was either in convent schools or at home. Emilie was taught at home, and showed great academic promise at a young age. It was the opinion of those close to her that she would have no great beauty, so excellent tutors and governesses were engaged to foster her intellect. Emilie proved to be a natural linguist, and mastered Latin, Italian, and English. She studied Virgil, Tasso, Milton, Horace, and Cicero. She also learned to ride and fence, but her true love was mathematics.
By her late teenage years, Emilie had become beautiful and independent, with a strong and passionate nature. She evaluated her prospects for marriage, realizing that she wanted a husband who would appreciate her while leaving her the independence she valued for pursuing her own interests. She found whom she sought in Florent-Claude, Marquis du Châtelet and Count of Laumont. They were married in 1725, when Emilie was 19 years old.
The Marquis and Marquise du Châtelet lived the next five years at Semur-en-Auxios, where Florent-Claude was governor. They had first a girl, Gabrielle Pauline, and then a boy, Louis-Marie-Florent, in 1726 and 1727. In 1730, Florent-Claude was made a regimental colonel. Thereafter he spent a significant amount of time with his troops. Emilie returned to the whirlwind of Paris high society, gambling, socializing, and enjoying ever more freedom.
When Emilie was 27 the couple had their last child, a boy called Victor-Esprit. He was not long-lived. It was after his birth that Emilie returned to the serious study of mathematics. She engaged fine tutors, and spent long hours in salons and cafés discussing all matters. One particular café was a gathering place for scientists and mathematicians, but when Emilie went there, she was not admitted. She returned to the café dressed as a man. Although her friends and colleagues inside were not fooled, she did gain admittance to join in their discourse.
Emilie’s interest in mathematics and science overlapped with her affairs of the heart. She was a friend to Alexis Claude Clairaut, who supported Newtonian physics when the French still favored Descartes. She had an affair with one of her tutors, Pierre Louis Moreau de Maupertius, who was also a supporter of Newton’s theories (Tee, 21).
It was in 1733 that Emilie began a friendship and affair with Voltaire that would last the rest of her life. Voltaire was exiled to England in the 1720s, and there he, too, had become a supporter of Newton. He continued to write philosophical interpretations of the world and of scientific work, and was often on the verge of arrest due to the controversial nature of his writings. In 1734, Voltaire and Emilie moved to a du Châtelet family home at Cirey, near the Belgian border, where they thought he could avoid persecution. There they set up a well-equipped lab, and spent their days studying and writing.
Voltaire and the Marquise often had guests at Cirey, but even then they worked throughout the days. Evenings were for entertainment, and Emilie enjoyed acting in theatrical scenes written by Voltaire. The Marquis du Châtelet sometimes stayed at Cirey, as well, and a respectful friendship seems to have existed between him and Voltaire.
When there were no guests, the couple worked almost without ceasing. Unbeknownst to Voltaire, Emilie entered an essay on the nature of fire in a contest sponsored by the French Academy of Science, a contest that he was also entering. Neither won, though they were both recognized for their work.
Voltaire published Éléments de la philosophie de Newton in 1738, though the work is thought by some to have been that of Emilie (Thornhill). Emilie, realizing that the classic physics text in use at the time was 80 years old, wrote a comprehensive textbook that she hoped her son would be able to use. Her text, Institutions de physique, was based on the theories of Leibniz, and was published in 1740 after some of her work with Koenig. Koenig spread rumors in Paris that the book was really his, and even when the truth was known Emilie felt her gender clouded people’s judgement of her work. Still, young scientists began to seek out Cirey to stay and study mathematics with the Marquise du Châtelet. Clearly, the merit of her work stood without regard to her gender.
Surrounded as she often was by proponents of Newton’s theories, Emilie began working on a translation and analysis of Newton’s Principia. This work included the idea that the force Kepler described as keeping the planets in their orbits and the force Galileo measured that makes objects fall down are the same force. Newton’s idea was formalized in the Principia as the theory of universal gravitation. His laws of motion predicted both behaviors, and had the effect of unifying seemingly unrelated events (Perl, 37).
In 1748, Emilie fell in love with the Marquis de Saint-Lambert while visiting at Luneville. He did not share her passion for life or work, but a relationship developed. Voltaire learned of the affair, but remained supportive of Emilie. When she became pregnant by Saint-Lambert, Voltaire helped to deceive the Marquis du Châtelet into believing that the baby she was carrying was that of her husband.
During the pregnancy in 1749, Emilie strove intensely to finish her work on Newton’s Principia. She continued to work until the birth of her second daughter, and it is generally told that the baby arrived quite suddenly while the Marquise was working at her desk, on September 2, 1749. Emilie seemed to be recovering normally after the birth, but died unexpectedly just days later, on September 10, 1749. Her daughter died soon after.
Emilie’s translation and algebraic commentary on the Principia remain her best known work. She made Newton’s work available to French scholars, and her synthesis contributed to the development of Newtonian science. The work, to which Voltaire added a historical preface, was finally published in 1759, ten years after Emilie du Châtelet’s death. It was reprinted in 1966, and remains the only French translation of the Principia.
|Contributed by Laurie Kiss|