Maupertuis returned to Berlin in the year 1744, when a marriage was nego tiated and brought about, by the good offices of the Queen mother, between our author and Mademoiselle de Borck, a lady of great beauty and merit, and nearly related to M. de Bora, at that time Mi nister of state. This determined him to settle at Berlin, as he was extremely at tached to his new spouse, and regarded this alliance as the most fiirtunate cir cumstance of his life.
In the year 1746, Maupertuis was de clared, by the King of Prussia, president of the Royal Academy of Sciences at Berlin, and soon after by the same prince was honoured with the Order of Merit. However, all these accumulated honours and adyantages, so far from lessening his ardour for the sciences, seemed to furnish new allurements to labour and applica tion. Not a day passed but he produced some new project or essay the the ad. vancement of knowledge. Nor did he confine himself to mathematical studies only ; metaphysics, chemistry, botany, polite literature, all shared his attention, and contributed to his fame. At the same time he had, it seems, a strange inquietude of spirit, with a dark atra bilaire humour, which rendered him mi serable amidst honours and pleasures. Such a temperament did not promise a pacific life ; and he was in fact engaged in several quarrels. One of these was with Koenig, the professor of philosophy at Franeker, and another more terrible with Voltaire. Maupertuis had inserted in the volume of memoirs of the academy of Berlin for 1746, a discourse upon the laws of motion ; which Koenig w as not content with attacking, but attributed to Leibnitz. Maupertuis, stung with the im putation of plagiarism, engaged the aca demy of Berlin to call upon him for his proof ; which Koenig failing to produce, his name was struck out of the academy, of which he was a member.
Several pamphlets were the conse quence of this measure ; and Voltaire, for some reason or other, engaged in the quarrel against Maupertuis. \Ye say, the seine reason or other, because Mauper tuis and .Voltaire were apparently upon the most amicable terms ; and the latter respected the former as his master in the mathematics. Voltaire, upon this occa sion, exerted all his wit and satire against him ; and upon the whole was so much transported beyond what was thought right, that he found it expedient, in 1753, to quit the court of Prussia.
Our philosopher's constitution had long been considerably impaired by the great fatigues of various kinds in which his active mind had involved him ; though, from the amazing hardships he had un dergone, in his northern expedition, most of his bodily sufferings may be traced. The intense sharpness of the air could only be supported by means of strong liquors, which helped but to lacerate his lungs, and to bring on a spitting of blood, which began at least twelve years before he died. Yet still his mind seemed to enjoy the greatest vigour ; for the best of his writings were produced, and most sublime ideas developed, during the time of his confinement by sickness, when he was unable to occupy his presidial chair at the academy. He took several journies to St Malo, during the last years of his life, for the recovery of his health ; and though he always received benefit by breathing his native air, yet still, upon his return to Berlin, his disorder likewise re turned with greater violence.
His last journey into France was under taken in the year 1757; when he was obliged, soon after his arrival there, to quit his favourite retreat at St. Maio, on account of the danger and confusion which that town was thrown into by the arrival of the English in its neighbour hood. From thence he went to Bour deaux, hoping there to meet with a neu tral ship to carry him to Hamburgh, in his way back to Berlin ; but being disap pointed in that hope, he went to Toulouse, where he remained seven months. He had then thoughts of going to Italy, in hopes a milder climate would restore him to health ; but finding himsellgrow worse, he rather inclined towards Germany, and went to Neufchatel, where for three months he enjoyed the conversation of Lord Marischal, with whom he had 'for merly been much connected. At length he arrived at Basil, Oct. 16, 1758, where he was received by his friend Bernoulli and his family with the utmost tenderness and affection. He at first found himself much better here than he had been at Neufchatel; but this amendment was of short duration ; for as the winter ap proached his disorder returned, accom panied by new and more alarming symp toms. He languished here many months, during which he was attended by M. de la Concamine, and died in 1759, at 61 years of age.
The works which he published were collected into 4 vols. 8vo. published at Lyons in 1756, where also a new and elegant edition was printed in 176&. These contain the following works : 1. Essay on Cosmology.-2. Discourse on the different Figures of the Stars.-3. Essay on Moral Philosophy.-4 Philoso phical Reflections upon the Origin of Lan guages, and the Signification of Words.— 5. Animal Physics, concerning Genera tion, &c.-6. System of Nature, or the Formation of Bodies.-7. Letters on va rious Subjects.-8. On the Progress of the Sciences.-9. Elements of Geogra phy.-10. Account of the Expedition to the Polar Circle, for determining the Figure of the Earth ; or the Measure of the Earth at the Polar Circle.-11. Ac count of a Journey into the Heart of Lap land, to search for an ancient Monu ment.-12. On the Comet of 1742.-13. Various Academical Discourses, pronoun ced in the French and Prussian Acade mies.-14. Dissertation upon 15. Agreement of the different Laws of Nature, which have hitherto appeared in compatible.-16. Upon the Laws of Mo tion.-17. Upon the Laws of Rest.-18. Nautical Astronomy.-19. On the Paral lax of the Moon.---20. Operations for de termining the • Figure of the Earth, and the Variations of Gravity.-21. Measure of a Degree of the Meridian at the Polar Circle.
Besides these works, Maupertuis was author of a great multitude of interesting papers, particularly those printed in the Memoirs of the Paris and Berlin Acade mies, far too numerous here to mention, viz. in the Memoirs of the Academy at Paris from the year 1724 to 1749; and in those of the Academy of Berlin, from the year 1746 to 1756.