Ch�telet-Lomont, Gabrielle �milie, Marquise du 1706-49
French mathematician and physicist

She was born in Paris, and after her marriage in 1725 to the Comte du Ch�telet-Lomont she studied mathematics and the physical sciences. In 1733 she met Voltaire, and became his mistress. Voltaire came to live with her at her husband's estate at Cirey, where they set up a laboratory and studied the nature of fire, heat and light. She connected the causes of heat and light, and believed that both represented types of motion. She wrote Institutions de physique (1740) and Dissertation sur la nature et la propagation du feu (1744. 'Dissertation on the Nature and Propagation of Fire'), but her chief work was her translation into French of Sir Isaac Newton's Principia Mathematica, posthumously published in 1759.