Chastelet, Gabriel Emilia De Breteuil, Marchioness

, descended of a very ancient family of Picardy, was born December 17, 1706. Among the women of her nation who have rendered themselves illustrious, she is certainly entitled to the first rank. Before her, many of them had acquired reputation by agreeable romances, and by poetical pieces, in which there appeared the graces of wit, and the charms of sentiment. Several also, by applying themselves to the study of languages, by making their beauties to pass into their own, and by enriching their versions with valuable commentaries, had deserved | well of the republic of letters. By composing works on subjects which unfold themselves only to men of rare genius, she has classed herself, in the opinion of her countrymen, with the greatest philosophers, and may be said to have rivalled Leibnitz and Newton. From her early youth she read the best authors, without the medium of a translation: Tasso, Milton, and Virgil were alike familiar to her; and her ear was particularly sensible to the melody of verse. She was endowed with great eloquence, but not of that sort which consists only in displaying wit or acquirements; precision was the character of her’s. She would rather have written with the solidity of Pascal than with the charms of S6vigne. She loved abstract sciences, studied mathematics deeply, and published an explanation of the philosophy of Leibnitz, under the title of “Institutions de Physique,” in 8vo, addressed to her son, the preliminary discourse to which is said to be a model of reason and eloquence. Afterwards she published a treatise on “The Nature of Fire.” To know common geometry did not satisfy her. She was so well skilled in the philosophy of Newton, that she translated his works, and enriched them by a commentary, in 4 vols. 4to its title is “Principes Mathematiques de la Philosophe Naturelle.” This work, which cost her infinite labour, is supposed to have hastened her death, which took place in 1749. With all her talents and personal qualifications, however, it is generally admitted that she had no pretensions to chastity. 1