The first work of importance from the pen of the Marquise was entitled _Institutions de Physique_. In it she gave an exposition of the philosophy of Leibnitz and dissertations on space, time and force. In the discussion of the last topic she seems to have anticipated some of the later conclusions of science respecting the nature of energy. Her most noted achievement, however, was her translation of Newton's _Principia_, the first translation into French of this epoch-making work. To translate this masterpiece from its original Latin, it was necessary that the Marquise, in order to make it intelligible to others, should have a thorough understanding of it herself. To the translation she added a commentary, which shows that Mme. du Chatelet had a mathematical mind of undoubted power. She labored assiduously on this great undertaking for many years and completed it only shortly before her death; but it was not published until ten years after her demise. In his _Elogie Historique_ on the Marquise's translation of the _Principia_, Voltaire, in his usual flamboyant style, declares "Two wonders have been performed: one that Newton was able to write this work, the other that a woman could translate and explain it." In an effort to express in a single sentence all his admiration for his talented friend he does not hesitate to state: "Never was woman so learned as she, and never did anyone less deserve that people should say of her, 'She is a learned woman.'" Again he refers to her with characteristic Frenchiness as "a woman who has translated and explained Newton, in one word a very great man--_en un mot un tres grand homme_."[122] But, although the extent of her attainments and her ability as a mathematician were unquestionable, she fell far short of her great contemporary, Gaetana Agnesi, both in the depth and breadth of her scholarship and in her power of infinitesimal analysis. As to her moral character, she was infinitely inferior to the saintly savante of Milan. She was by inclination and profession an Epicurean and an avowed sensualist. In her little treatise, _Reflexions sur le Bonheur_--Reflections on Happiness--she unblushingly asserts "that we have nothing to do in this world except procure for ourselves agreeable sensations." Considering her profligate life, bordering at times on utter _abandon_, we are not surprised that one of her countrymen has characterized her as "_Femme sans foi, sans moeurs, sans pudeur_,"--a woman without faith, without morals, without shame.[123] Anna Barbara Reinhardt of Winterthur in Switzerland was another woman of exceptional mathematical talent. She is remarkable for having extended and improved the solution of a difficult problem that specially engaged the attention of Maupertuis. According to so competent an authority as Jean Bernouilli, she was the superior, as a mathematician, of the Marquise de Chatelet.