MERSENNE (Martin)

, a learned French author, was born at Bourg of Oyse, in the province of Maine, 1588. He studied at La Fleche at the same time with Des Cartes; with whom he contracted a strict friendship, which continued till death. He afterwards went to Paris, and studied at the Sorbonne; and in 1611 entered himself among the Minims. He became well skilled in Hebrew, philosophy, and mathematics. From 1615 to 1619, he taught philosophy and theology in the convent of Nevers; and became the Superior of that convent. But being desirous of applying himself more freely and closely to study, he resigned all the posts he enjoyed in his order, and retired to Paris, where he spent the remainder of his life; excepting some short excursions which he occasionally made into Italy, Germany, and the Netherlands.

Study and literary conversation were afterwards his whole employment. He held a correspondence with most of the learned 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; being 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. No person was more curious in penetrating into the secrets of nature, and carrying all the arts and sciences to perfection. He was the chief friend and literary agent of Des Cartes at Paris; giving him advice and assistance upon all occasions, and informing him of all that passed at Paris and elsewhere. For, being a person of universal learning, but particularly excelling in physical and mathematical knowledge, Des Cartes scarcely ever did any thing, or at least was not perfectly satissied with any thing he had done, without sirst knowing what Mersenne thought of it. It is even said, that when Mersenne gave out in Paris, 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, he immediately sent notice to Des Cartes, that a vacuum was not then the fashion at Paris; upon which, that philosopher changed his system, and adopted the old doctrine of a plenum.

Mersenne was a man of good invention also himself; and he 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. After a very studious and useful life, he died at Paris in 1648, at 60 years of age.

Mersenne was author of many useful works, particularly the following:

1. Questiones celeberrimæ in Genesim.

2. Harmonicorum Libri.

3. De Sonorum Natura, Causis, et Effectibus.

4. Cogitata Physico-Mathematica; 2 vols. 4to.

5. La Verité des Sciences.

6. Les Questions inouies.

Besides many letters in the works of Des Cartes, and other authors.