Émilie du Châtelet (1706–1749)

Émilie du Châtelet was born in Paris to a family of French minor nobility. Her parents were baron Louis Nicholas le Tonnelier de Breteuil and his wife Gabrielle Anne de Froullay. Her father, who was at that time the principal secretary and introducer of ambassadors to King Louis XIV, held a weekly salon that attracted well-known writers and scientists.
He hired tutors to teach Emilie to speak Latin, Italian, Greek and German; she would later publish translations into French of Greek and Latin plays and philosophy. She also received a rare education for a girl of her time in mathematics, literature, and science. In 1725, at age 19, she was married to the marquis Florent-Claude de Châtelet-Lomont, with whom she had three children. She met Voltaire, who became her lover and life-long intellectual companion, in 1733, and they retired to her country estate at Cirey in the Haute-Marne in northeastern France. The house was remodeled to include a laboratory with instruments for their shared passion for scientific experiments.

In her intellectual work, Madame du Châtelet focused particularly on Newton, Leibniz, and Christian Wolff.

In 1740, she published the book Institutions de Physique (The Foundations of Physics), a highly original work in natural philosophy. Early in that 1740s, she began work on her greatest achievement, a two-volume translation of and commentary on Newton's Principia. She died shortly after completing this work, which remained unpublished until 1759. It is still the leading French translation of Newton's book.

Among other works, she also translated Bernard Mandeville's book The Fable of the Bees; wrote a critical analysis on the Bible called Examens de la Bible; and a semi-autobiographical book on the nature of happiness, Discours sur le bonheur. In 1748, at age 42, she began an affair with Jean-François de Saint-Lambert, a poet, and became pregnant with her fourth child. She gave on September 4, 1749 and died six days later.