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Unraveling the mystery of Marquise Du Châtelet

Marquise Du Châtelet was a mother, wife, mathematician, physicist, author, and mistress of Voltaire. Marquise Du Châtelet was a mother, wife, mathematician, physicist, author, and mistress of Voltaire. (FROM THE COLLECTION OF THE CHATEAU DE BRETEUIL)

La Dame d’Esprit: A Biography of the Marquise Du Châtelet, By Judith P. Zinsser, Viking, 376 pp., illustrated $24.95

Judith Zinsser's "La Dame d'Esprit: A Biography of the Marquise Du Châtelet," is at heart a mystery story. As a daughter, wife, and mother, the marquise fulfilled her duties with aplomb. Born in Paris in 1706 to a noble family, Gabrielle Émilie le Tonnelier de Breteuil studied etiquette, speech, and deportment. At 18 she married the Marquis Du Châtelet-Lomont , a military officer and member of one of France's most elite families. She supervised her household, oversaw her children's education, advanced the family's interests, and found time to enjoy the pleasures of Paris, from shopping excursions to masked balls. How and why, then, did this apparently conventional woman become a mathematician and physicist; an author of works on Newton, Descartes, and Leibniz ; and mistress of Voltaire?

Even with such sources available as Du Châtelet's letters and writings, Zinsser must contend with many gaps in the record; little is known, for example, about her subject's childhood. Nevertheless, Zinsser admirably charts her journey, demonstrating her scholarly gifts and her flair for arranging circumstances to her liking.

Upper-class girls in 18th-century France were typically schooled in "Christian piety" and "the virtues and good morals . . . appropriate to their sex." Du Châtelet had other ideas. "If I were king," she wrote, "I would establish [elite secondary schools] for women." Ambition, in her view, was an "insatiable" quality. Throughout her life, she made it her business to find ways to do what she wanted; unburdened by guilt or self-doubt, she studied the cosmos, starred in theatricals, attended the queen, took lovers.

Voltaire was already a leading playwright and a scourge of authority when he and Du Châtelet met in Paris in 1733. Protecting him from the legal consequences of his notorious outspokenness would prove another of her chief occupations. In 1735, the two retired to Cirey , the Du Châtelet country estate, where they embarked on a life of shared reading, scientific experimentation, and writing. Du Châtelet thought of Cirey as a "paradise on earth," her own academy of learning.

The "wonder" of Du Châtelet, Zinsser argues, is that she saw no conflict between women's prescribed roles and her own intellectual aspirations. In a "Discours" on happiness, she reasoned that since women's "estate" excluded them from war, government, and diplomacy, they could achieve glory by cultivating knowledge. Friendships with "people who think," boredom with the social whirl of Paris, and the French publication of John Locke's "Essay on Human Understanding" in 1729 all inspired her to rechannel her passions. Her studies offered an alternative to a life spent, in her words, "doing stupid things, repairing them, and repenting them." Happily, she had a sympathetic, obliging husband.

Zinsser conveys Du Châtelet's strong-willed personality and contrarian outlook. Her books won praise and recognition, but when a critic reviewed her work unfavorably, she fought back. She once called Jesus "a pious fraud." Her manuscripts, filled with painstaking notations, reflect the devotion she brought to her scientific studies.

The author challenges historians who have explored her subject's love life at the expense of her accomplishments. She emphasizes how Du Châtelet became increasingly adventurous in her studies, formulating her own questions and ideas independently of Voltaire and other mentors. Du Châtelet's is finally a story of luck and imagination; while birth and connections eased her way, she decided for herself what a life of privilege could hold.