CHASTELET, shit-la, Gabrielle Emilie Breteuil, bre-te-yei, MARQUISE DU : b. Picardy 1706; d. Luniville 1749. She was of an ancient family, was taught Latin by her father, Baron •Breteuil, and was well acquainted with that language; but her favorite study was mathe matics. She had a sound judgment and much taste, loved society and the amusements of her age and sex, but after the publication of the (Philosophical Letters' by Voltaire had roused the Jesuits' criticism against him, she abandoned all these pleasures, and in 1733 retired with him to the dilapidated castle of Cirey, situated in a dreary region on the borders of Champagne and Lorraine. She embellished this residence; formed a library, collected instruments, etc. Cirey was often visited by the learned,— by Maupertuis, John Bernouilli, etc. Here the Marchioness learned English of Voltaire in the space of three months, and read with him New ton, Locke and Pope. She also wrote an analy
sis of the system of Leibnitz, and translated Newton's with an algebraic com mentary. Voltaire lived six years with her at Cirey, where they employed their time in the study of science, and in getting up lovers' quar rels for the pleasure of patching them up again. At the end of this time she went to. Brussels to prosecute a lawsuit, which was terminated by an advantageous compromise, brought about by Voltaire. She also carried on a correspond; ence with the philosopher, Wolf, until her death. Her 'Trade de la nature du feu' obtained•the prize of the Parisian Academy of Sciences, and is published in their collections. Her husband, the Marquis du Chastelet Lomont, was high-steward of King Stanislaus Lesczin sky at Luneville.