Mersenne, Marin

, a learned French writer, was born at Oyse, in the province of Maine, Sept. 8, 1588. He cultivated the belles lettres at the college of la Flche; and afterwards went to Paris, and studied divinity at the Sorbonne. Upon his leaving the schools of the Sorbonne, he entered himself among the Minims, and received the habit of that order, July 17, 1611. In 1612 he went to reside in the convent of Paris, where he was ordained priest. He then applied himself to the Hebrew language, which he learned of father John Bruno, a Scotch Minim. From 1615 to 1619, he taught philosophy and theology in the convent of Nevers; and then returned to Paris, where he spent the remainder of his life. Study and conversatioa were afterwards his whole employment. He held a correspondence with most of the principal men of his time; being as it were the very centre of communication between literary men of all countries, by the mutual correspondence which he managed between them; and was in France what Mr. Collins was in England. He omitted no opportunity to engage them to publish their works; and the world is obliged to him for several excellent discoveries, which would probably have been lost, but for his encouragement; and on all accounts he had the reputation of being one of the best men, as well as philosophers, of his time. He was the chief friend and literary agent of Des Cartes, in particular, with whom he had contracted a friendship while he studied at la Flche, which continued to his death. He was that philosopher’s chief agent at Paris. Thus, when Mersenne gave out in that city, that Des Cartes was erecting a new system of physics upon the foundation of a vacuum, and found the public very indifferent to it on that very account, it was said, that he immediately sent intelligence to Des Cartes, that a vacuum was not then the fashion at Paris; which made that philosopher change his system, and adopt the old doctrine of a plenum. In the mean time, Mersenne’s residence at Paris did not hinder him from making several journies into foreign countries; for he went to Holland in 1629, and | stayed a year there; and he was in Italy four times; in 1639, 1641, 1644, and 1646. He fell sick, in 1648, of an abscess in the right side, which the physicians took to be a bastard pleurisy and bled him several times to no purpose. At last it was thought proper to open the side but he expired in the midst of the operation, when he was almost sixty years of age. He ordered the physicians at his death to open his body, which they did, and found an abscess two inches above the place where they had opened his side; so that, if the incision had been made at the proper place, his life might possibly have been saved.

He was a man of universal learning, but excelled so much in physical and mathematical knowledge, that Des Cartes scarcely ever did any thing, or at least was not perfectly satisfied with any thing he had done, without first knowing what Mersenne thought of it. He published a great many books, the first of which occasioned him some trouble. The title is, “Qusestiones celeberrimse in Genesim, cum accurata textus explicatione: in quo volumine athei & deisti impugnantur,” &c. Paris, 1623. Two sheets of this book, from column 669 to column 676 inclusive, were suppressed by him; and it is very difficult to meet with any copy in which these sheets are not taken out. He had given there a list of the atheists of his time, mentioned their different works, and specified their opinions, as appears from the index in the word Athei, which has not been altered. Whether this detail was thought of dangerous consequence, or whether Mersenne had enlarged too much the number of atheists, it was judged proper that he should retrench all he had said upon that subject. Baillet calls Mersenne, to whose 671st page he refers, the most credulous man alive for believing, that there could be at that time, us he supposes, 50,000 atheists in Paris; and considers this pretended number, as nothing more than a fiction of the Hugonots, that they might take, occasion thence to abuse the catholics. In this work, he has undoubtedly inserted a variety of things which are of a nature foreign to his main subject. Thus he calls it in his title-page, “Opus theologis, philosophis, medicis, jurisconsuhis, mathematicis, musicis vero & catoptricis praesertim utile.” His largest digression relatesao music, which be had studied, and upon which he wrote several books. He attacks also Dr. Robert Fludd, fellow of the college of physicians in London; the severity of whose answers raised up many defenders for Mersenne, and among the rest the | illustrious Gassendi, whose tract on this subject was printed at Paris in 1628, under this title: “Epistolica exercitatio, in qua proecipua principia philosophise Robert! Fludd deteguntur, & ad recentes illius libros ad versus patrem Marimim Mersennum scriptos respondetur.” This piece is reprinted in the third volume of Gassendi’s works at Paris, in 1658, under the title of “Examen philosophic Fltiddanae,” &c.

Mersenne was a man of good invention; and had a peculiar talent in forming curious questions, though he did not always succeed in resolving them; however, he at least gave occasion to others to do it. It is said* he invented the Cycloid, otherwise called the Roulette. Presently the chief geometricians of the age engaged in the contemplation of this new curve, among whom Mersenne himself held a distinguished rank.

Mersenne was author of many useful works, particularly the following: 1. “Questiones celeberrimae in Genesim,” already mentioned. 2. “Harmonicorum Libri.” 3. “De Sonorum Natura, Causis, et Effectibus.” 4. “Cogitata Physico-Mathematica,” 2 vols. 4to. 5. “La Verite des Sciences.” 6. “Les Questions inouies.” He has also many letters in the works of Des Cartes, and other authors. ¹