The Polish astronomer, Hevilius, who had an observatory at Dantzig, is noted for having made the most accurate observations that had been known before the adaptation of the telescope to astronomical instruments. He is also noted for his _Prodromus Astronomiae_, a catalogue of 1,888 stars; for his _Selenographia_, containing accurate descriptions and drawings of the moon in her different phases and librations, and for his _Machina Coelestis_, which contained the results of forty years of observations and labor. Much of his success and eminence, however, was due to his intelligent and devoted wife, Elizabeth, who, during twenty-seven years, was a zealous collaborator and should share the credit usually given to her husband. It was she who, after his death, edited and published their joint work, the _Prodromus Astronomiae_. Among the women most distinguished in the eighteenth century for astronomical pursuits was the Marquise du Chatelet, who was likewise famous for her knowledge of mathematics. It was she who accomplished the difficult task of translating Newton's _Principia_ into French. "This translation," writes Voltaire, "which the most learned men of France should have made and which the others should study, was undertaken by a woman and completed to the astonishment and glory of her country."[140] France was at this time devoted to the doctrines of Descartes and to his theory of elementary vortices; and Voltaire, who had been deeply impressed by the admirable simplicity of Newton's theory of universal attraction as a means of explaining the seemingly complex motions of the heavenly bodies, resolved to make his countrymen acquainted with the teachings of the great English geometer and, at the same time, dethrone Descartes in the French Academy. It was, indeed, a huge undertaking; but, thanks to the ability which Mme. du Chatelet displayed in translating and elucidating Newton's immortal masterpiece, he lived to see his dream realized. How proud Mme. du Chatelet's countrywomen must have been of her! How they must have rejoiced in her success and acclaimed her as the intellectual glory of her sex! How they must have pointed to her work as a triumphant refutation of the age-old belief in woman's incapacity for mathematics and all abstract science! How they must have been elated to find one of their number successfully executing a task which would have taxed the powers of the most eminent mathematicians of France! How they must have associated her truly notable performance with similar achievements of Hypatia and Maria Gaetana Agnesi and discerned in it concrete evidence of the falsity of all those imputations of mental inferiority which had been fostered by "man's huge egotism and woman's carefully coddled superstition." How they must have been encouraged by her achievement and spurred on to emulate her by similar contributions to the advancement of science!