Émilie du Châtelet field of work mathematics
Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (French pronunciation: [emili dy ʃɑtlɛ] (listen); 17 December 1706 – 10 September 1749) was a French natural philosopher and mathematician from the early 1730s until her death due to complications during childbirth in 1749.
Her most recognized achievement is her translation of and commentary on Isaac Newton's 1687 book Philosophiæ Naturalis Principia Mathematica containing basic laws of physics. The translation, published posthumously in 1756, is still considered the standard French translation.
Her commentary includes a contribution to Newtonian mechanics—the postulate of an additional conservation law for total energy, of which kinetic energy of motion is one element. This led to her conceptualization of energy as such, and to derive its quantitative relationships to the mass and velocity of an object.
Her philosophical magnum opus, Institutions de Physique (Paris, 1740, first edition; Foundations of Physics), circulated widely, generated heated debates, and was republished and translated into several other languages within two years of its original publication.
She participated in the famous vis viva debate, concerning the best way to measure the force of a body and the best means of thinking about conservation principles. Posthumously, her ideas were heavily represented in the most famous text of the French Enlightenment, the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert, first published shortly after du Châtelet's death.
Numerous biographies, books and plays have been written about her life and work in the two centuries since her death. In the early 21st century, her life and ideas have generated renewed interest.
Émilie du Châtelet had, over many years, a relationship with the writer and philosopher Voltaire.Resumption of studies
After bearing three children, Émilie, Marquise du Châtelet, considered her marital responsibilities fulfilled and reached an agreement with her husband to live separate lives while still maintaining one household. In 1733, aged 26, du Châtelet resumed her mathematical studies. Initially, she was tutored in algebra and calculus by Moreau de Maupertuis, a member of the Academy of Sciences; although mathematics was not his forte, he had received a solid education from Johann Bernoulli, who also taught Leonhard Euler. However by 1735 du Châtelet had turned for her mathematical training to Alexis Clairaut, a mathematical prodigy known best for Clairaut's equation and Clairaut's theorem. Du Châtelet resourcefully sought some of France's best tutors and scholars to mentor her in mathematics. On one occasion at the Café Gradot, a place where men frequently gathered for intellectual discussion, she was politely ejected when she attempted to join one of her teachers. Undeterred, she returned and entered after having men's clothing made for her.Relationship with Voltaire
Du Châtelet may have met Voltaire in her childhood at one of her father's salons; Voltaire himself dates their meeting to 1729, when he returned from his exile in London. However, their friendship developed from May 1733 when she re-entered society after the birth of her third child.Du Châtelet invited Voltaire to live at her country house at Cirey in Haute-Marne, northeastern France, and he became her long-time companion. There she studied physics and mathematics and published scientific articles and translations. To judge from Voltaire's letters to friends and their commentaries on each other's work, they lived together with great mutual liking and respect. As a literary rather than scientific person, Voltaire implicitly acknowledged her contributions to his 1738 Elements of the Philosophy of Newton. This was through a poem dedicated to her at the beginning of the text and in the preface, where Voltaire praised her study and contributions. The book's chapters on optics show strong similarities with her own Essai sur l'optique. She was able to contribute further to the campaign by a laudatory review in the Journal des savants.Sharing a passion for science, Voltaire and du Châtelet collaborated scientifically. They set up a laboratory in du Châtelet's home in Lorraine. In a healthy competition, they both entered the 1738 Paris Academy prize contest on the nature of fire, since du Châtelet disagreed with Voltaire's essay. Although neither of them won, both essays received honourable mention and were published. She thus became the first woman to have a scientific paper published by the Academy.
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