Emilie du Châtelet
Gabrielle Émilie Le Tonnelier de Breteuil, marquise du Châtelet (1706 – 1749) was a France mathematician, physicist, and author during the age of intellectual enlightenment. Châtelet’s research predicted what is today known as infra-red radiation and the nature of light. In the year of her death, she completed the work regarded as her outstanding achievement: her translation into French, with her own commentary, of Newton’s Principia Mathematica, including her derivation from its principles of mechanics the notion of conservation of energy.
Early Life and Education
Her father was the Principal Secretary and Introducer of Ambassadors to Louis XIV. Émilie’s father, recognising her early brilliance, arranged for Fontenelle, the perpetual secretary of the Frency Académie des Sciences to visit and talk about astronomy with her when she was 10 years old. By the age of twelve she was fluent in Latin, Italian, Greek and German; she was later to publish translations into French of Greek and Latin plays and philosophy. She received education in mathematics, literature and science. As a teenager, she used her mathematical skills to devise highly successful strategies for gambling.
Marriage and Relationships
On 20 June 1725 she married the Marquis Florent-Claude du Chastellet, and thus became Marquise du Chastellet (the spelling Châtelet was introduced by Voltaire, and has now become standard). It was an Arranged marriage . After bearing three children, Émilie, considering her marital responsibilities fulfilled, made an agreement with her husband to live separate lives while still maintaining one household.
At the age of twenty-four Émilie du Châtelet had an affair with the Duc de Richelieu that lasted for a year and a half. Châtelet expressed an interest in the works of Isaac Newton, and Richelieu encouraged her to take lessons in higher mathematics to better understand his theories. Moreau de Maupertuis, a member of the Academy of Sciences, became Châtelet’s tutor in geometry. He was a mathematician, astronomer and physicist, and supported Newton’s theories. Émilie had an affair also with Voltaire, after he returned from his exile in London. Châtelet invited him to live in her country house at Cirey-sur-Blaise in Haute-Marne, and he became her long-time companion. There she studied physics and mathematics and published scientific articles and translations.
In her early 40s, she had an affair with the poet Jean François de Saint-Lambert and became pregnant. Châtelet bore the child, but died six days later from an embolism at the age of 42. Voltaire, in a letter to his friend King Frederick II of Prussia, declared that du Châtelet was “a great man whose only fault was being a woman”.
n 1737, Châtelet published a paper entitled Dissertation sur la nature et la propagation du feu, based upon her research into the science of fire, that predicted infra-red radiation and the nature of light. Her book Institutions de Physique (“Lessons in Physics”) published in 1740; sought to reconcile complex ideas from the leading thinkers of the time. In it she combined the theories of Gottfried Leibniz and the practical observations of Willem ‘s Gravesande to show that the energy of a moving object is proportional not to its velocity, as had previously been believed by Newton, Voltaire and others, but to the square of its velocity (E ∝ v²). She also translated Newtown’s Principia Mathematica with her own commentary in 1749.
Today du Châtelet’s translation of Principia Mathematica is still the standard translation of the work into French. A crater on Venus has been named in her honour.