# 1911 Encyclopædia Britannica/Mersenne, Marin

**MERSENNE, MARIN** (1588–1648), French philosopher and
mathematician, was born of peasant parents near Oizé (Sarthe)
on the 8th of September 1588, and died in Paris on the 1st of
September 1648. He was educated at the Jesuit College of
La Flèche, where he'was a fellow-pupil and friend of Descartes.
In 1611 he joined the Minim Friars, and devoted himself to
philosophic teaching in various convent schools. He settled
eventually in Paris in 1620 at the convent of L'Annonciade.
For the next four years he devoted himself entirely to philosophic
and theological writing, and published *Questions celeberrimae*
*in Genesim* (1623); *L'Impiété des déistes* (1624); *La Vérité des*
*sciences* (1624). These works are characterized by wide scholarship
and the narrowest theological orthodoxy. His greatest
service to philosophy was his enthusiastic defence of Descartes,
whose agent he was in Paris and whom he visited in exile in
Holland. He submitted to various eminent Parisian thinkers
a manuscript copy of the *Meditations*, and defended its orthodoxy
against numerous olerical critics. In later life, he gave up
speculative thought and turned to scientific research, especially
in mathematics, physics and astronomy. Of his works in this
connexion the best known is *L'Harmonie universelle* (1636),
dealing with the theory of music and musical instruments.

Among his other works are: *Euclidis elementorum libri*, &c.
(Paris, 1626); *Universae geometriae synopsis* (1644); *Les Mécaniques*
*de Galilée* (Paris, 1634); *Questions inouies on récréations des savants*
(1634); *Questions théologiques, physiques*, &c. (1634); *Nouvelles*
*découvertes de Galilée* (1639); *Cogitata physico-mathematica* (1644).

See Baillet, *Vie de Descartes* (1691); Poté, *Éloge de Mersenne*
(1816).