MAUPERTUIS (PATER Louis Mori CEAU as), a celebrated French mathe matician and philosopher, was born at St. Malo in 169S, and was there private ly educated till he attained his sixteenth year, when he was placed under the celebrated professor of philosophy, M. Le Blond, in the college of La Marche, at Paris ; while AL Guisnee, of the Acade my of Sciences, was his instructor in ma thematics.
For this science he soon discovered a strong inclination, and particularly for geometry. He likewise practised in strumental music, in his early years, with great success ; but fixed on no pro• fession till he was twenty, when he en tered into the army ; in which he re mained about five years, during. which time he pursued his mathematical studies with great vigour ; and it was soon re marked by M. Freret, and other acade micians, that nothing but mathematics could satisfy his active soul and unbound ed thirst for knowledge.
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. During the first years of his admission, he did not wholly confine his attention to ma thematics; he dipped into natural philoso phy, and discovered great knowledge and dexterity in observations and experi ments upon animals.
If the custom of travelling into remote countries, like the sages of antiquity, in order to be initiated into the learned mys teries of those times, had still subsisted, no one would have conformed to it with more eagerness than Maupertuis. His first gratification of this passion was to visit the country which haul given birth to Newton ; and during his residence at London he became as zealous an admirer and follower of that philosopher as any of his own countrymen. His next excur sion was to Basil in Switzerland, where he formed a friendship with the celebrat ed John flernoulli and his family, which continued till his death. At his return to Paris, he applied himself to his favourite studies with greater zeal than ever. And how well he fulfilled the duties of an academician, may be seen by running over the memoirs of the academy from the year 1724 to 1744; where it appears be was neither idle, nor occupied by ob jects of small importance. The most sublime questions in the mathematical sciences, received from his hand that elegance, clearness, and precision, so remarkable in all his writings.
In the year 1736, he was sent to the polar circle, to measure a degree of the meridian, in order to ascertain the figure of the earth ; in which expedition he was accompanied by Messrs. Clairault, Camus, Monnier, Outhier, and Celsus, the celebrated professor of astronomy at Upsal. This business rendered him so famous, that on his return he was ad mitted a member of almost every acade my in Europe.
In the year 1740, Maupertuis had an invitation from the King of Prussia to go to Berlin ; which was too flattering to be refused. His rank among men of letters had not wholly effaced his love for his profession, that of arms. He followed the King to the field, but at the battle of Molwitz. was deprived of the pleasure of being present, when victory declared in favour of his royal patron, by a singular kind of adventure. His horse during the beat of the action running away with him, lie fell into the hands of the enemy ; and was at first but roughly treated by the Austrian Hussars, to whom he could not make .himself known for want of lan guage ; but being carried prisoner to Vienna, he received such honours from the Emperor as never were effaced from his memory. Maupertuis lamented very much the loss of a watch of Mr.Graham's, the celebrated English artist, which they had taken from him ; the Emperor, who happened to have another by the artist, but enriched with diamonds, pre sented it to him, saying, " The Hussars meant only to jest with you, they have sent me your watch, and I return it to you." Ile went soon after to Berlin, but as the refhrm of the academy which the King of Prussia then meditated was not yet mature, he repaired to Paris, where his affitirs called him, and was chosen, in 1742, director of the Academy of Sciences. In 1743, he was received into. the French Academy, which was the first instance of the same person being a mem ber of both the academies at Paris at the same time. Maupertuis again assumed the soldier at the siege of Fribourg, and was pitched upon by Marshal Coigny and the Count d'Argenson, to carry the news to the French King of the surrender of that citadel.