Gabrielle du Chatelet-Lomont. Portrait of Gabrielle Emilie Chatelet-Lomont (1706-49), French physicist. As she was tall, Chatelet-Lomont's father believed her unmarriageable and so provided her with an education. Chatelet-Lomont did marry and also became the mistress of Voltaire. With Voltaire she studied the nature of fire, heat and light, believing that all three were types of motion. She translated Isaac Newton's Principia Mathematica into French. She helped to popularise Newton's and Leibniz's work in France, though the translation of Principia was not published until ten years after her death.