Pierre-Louis Moreau de, a celebrated French academician, was born at St Malo in the year 1698. At the age of sixteen he was placed under the eminent professor of philosophy M. le Blond, in the college of La Marche at Paris, where he displayed a peculiar aptitude for mathematical studies, and particularly for geometry. He entered the army at the age of twenty, and first served in the Gray Musketeers; but in the year 1720 his father purchased for him a company of cavalry in the regiment of La Roche-Guyon. He remained only five years in the army, during which time he pursued his mathematical studies with great vigour and success. In the year 1723 he was received into the Royal Academy of Sciences, and read his first performance, which was a memoir upon the construction and form of musical instruments (15th November 1724). During the first years of his admission he did not wholly confine his attention to mathematics; he likewise turned his attention to natural philosophy, and made ingenious observations and experiments upon animals. Maupertuis made a pilgrimage to the country which gave birth to Sir Isaac Newton; and during his residence in London he became as zealous an admirer and follower of that philosopher as any one of his own countrymen. On his return, he visited Basle in Switzerland, where he formed a friendship with John Bernoulli which continued till his death. Returning to Paris, he applied himself to his favourite studies with greater zeal than ever, of which abundant evidence is to be found in the Memoirs of the Academy from the year 1724 to 1736. The most sublime questions in geometry and the relative sciences were handled with that peculiar elegance, clearness, and precision, so remarkable in all his writings. In the year 1736 he was sent by the King of France to the polar circle to measure a degree of the meridian, in order to ascertain the figure of the earth, accompanied by MM. Clairaut, Camus, Le Monnier, the Abbé Outhier, and Celsius the celebrated professor of astronomy at Upsal. This distinction rendered him so famous that at his return he was admitted a member of almost every academy in Europe. In the year 1740 Maupertuis received an invitation from the King of Prussia to go to Berlin, which was too flattering to be refused. Having followed his Prussian majesty into the field to witness the battle of Mollwitz, his horse, during the heat of the action, ran away with him, and falling into the hands of the enemy, he was carried prisoner to Vienna, where he received distinguished honours from their imperial majesties. On his return to Paris, Maupertuis was in 1742 chosen director of the Academy of Sciences. In 1753 he was received into the French Academy, which was the first instance of the same person being at the same time a member of both the academies at Paris. He again assumed the character of a soldier at the siege of Fribourg, and was employed, on the surrender of that citadel, to carry the news to the French king. Having in 1744 married Mademoiselle de Borck, a lady nearly related to M. de Borck, then minister of state at the court of Berlin, Maupertuis took up his residence at that city. In the year 1746 he was chosen president of the Royal Academy of Sciences at Berlin; and soon afterwards was honoured with the Order of Merit. However, all these accumulated honours and advantages only furnished new allurements to labour and application. Nor did he confine himself solely to mathematical studies: metaphysics, chemistry, botany, polite literature, all shared his attention, and contributed to his fame. At the same time his temper was none of the best, and he had the misfortune to be engaged in several quarrels. He had a dispute with Koenig, the professor of philosophy at Franeker, and another of a more serious kind with Voltaire. The former unjustly charged Maupertuis with plagiarizing from Leibnitz; and the latter, with his accustomed wit and satire, exposed the cause of the German professor. The dispute became so serious that Maupertuis found it expedient in 1753 to quit the court of Prussia. Maupertuis's constitution had long been considerably impaired by the fatigues of various kinds in which his active mind had involved him; indeed, to the amazing hardships he had undergone in his northern expedition most of his future bodily sufferings may be traced. Yet his mind seemed still to possess the greatest vigour; for the best of his writings were produced, and his most sublime ideas developed, during the time of his confinement by sickness, when he was unable to occupy his chair as president at the academy. He took several journeys to St Malo in quest of health; and after visiting Toulouse and Neufchatel, he at length arrived at Basle on the 16th of October 1758, where he was received by his friend John Bernoulli and his family with the utmost tenderness and affection. He at first found himself much better there than he had been at Neufchatel; but this amendment was of short duration; for, after languishing here many months, he died in 1759.

The works of Maupertuis were collected into 4 volumes 8vo, and published in 1759 at Lyons, where a new and elegant edition was also printed in 1768. These consist of: Essai de Cosmologie, first published at Berlin in 1748; Discours sur la Figure des Astres, first published in 1732; Essai de Philosophie Morale, in which he maintains that the sum of evil surpasses that of good; Réflexions Philosophiques sur l'Origine des Langues et la Signification des Mots; Venus Physique, or an Exposition of the System of Generation; Système de la Nature, first published in 1751, and which may be considered as the sequel of the preceding work; Lettres on various subjects; Éléments de Géométrie, published at Paris in 1742, and containing a solution of the problem for determining the figure of the earth; Relation d'un Voyage fait par ordre du Roi au Cirque Polaire, printed at Paris as early as 1738; Relation d'un Voyage au fond de la Laponie; Lettre on the Comet of 1742; Discours Académiques, pronounced in the French and Prussian Academies; Mémoire sur la moindre quantité d'Action d'Astronomie Nautique, a work much praised when it first appeared, but now little read; Parallaxe de la Lune; Mémoire du Degré du Nord. Besides these treaties, Maupertuis was the author of a great number of papers, printed partly in the Memoirs of the French Academy of Sciences, and partly in those of the Academy of Berlin.