Marin Mersenne (pronounced Mehr-SENN) was born of peasant parents near Oizé, Maine (present day Sarthe, France). He was educated at Le Mans and at the Jesuit College of La Flèche. On 17 July 1611, he joined the Minim Friars, and, after studying theology and Hebrew in Paris received his full holy orders in 1613.
Between 1614 and 1618, he taught theology and philosophy at Nevers, but he returned to Paris and settled at the convent of L'Annonciade in 1620. There, with other kindred spirits such as René Descartes, Étienne Pascal, Gilles de Roberval and Nicolas-Claude Fabri de Peiresc, he studied mathematics and music. He corresponded with Giovanni Doni, Constantijn Huygens and other scholars in Italy, England and Holland.
He was a staunch defender of Galileo,
assisting him in translations of some of his mechanical works.
For four
years, Mersenne devoted himself entirely to philosophic and theological
writing, and published Quaestiones celeberrimae in Genesim (1623); L'Impieté des déistes (1624); La Vérité des sciences (Truth of the Sciences against the Sceptics, 1624). It is sometimes incorrectly stated that he was a Jesuit. He was educated by Jesuits, but he never joined the Society of Jesus. He taught theology and philosophy at Nevers and Paris. In 1635 Mersenne met with Tommaso Campanella,
but concluded that he could "teach nothing in the sciences (...) but
still he has a good memory and a fertile imagination." Mersenne asked if
René Descartes
wanted Campanella to come to Holland to meet him, but Descartes
declined. He visited Italy fifteen times, in 1640, 1641 and 1645. In
1643-1644 Mersenne also corresponded with the German Socinian Marcin Ruar concerning the Copernican ideas of Pierre Gassendi, finding Ruar already a supporter of Gassendi's position.
Among his correspondents were Josh, Dekar, Galilei, Roberval, Pascal,
Bekman and other scientists. Peter L. Bernstein in his book Against the Gods: the Remarkable story of risk
writes: "The Académie des Sciences in Paris and the Royal Society in
London, which were founded about twenty years after Mensenne's death,
were direct descendants of Mersenne's activities.
In later life, he gave up speculative thought and turned to
scientific research, especially in mathematics, physics and astronomy.
In this connection, his best known work is Traité de l'harmonie universelle (also referred to as Harmonie universelle) of 1636, dealing with the theory of music and musical instruments. It is regarded as a source of information on 17th-century music, especially French music and musicians, to rival even the works of Pietro Cerone.
One of his many contributions to musical tuning theory was the suggestion of
![\sqrt[4]{\frac{2}{3-\sqrt{2}}}](http://upload.wikimedia.org/math/4/6/b/46b74044f0d5e3e817ac405cab7da53f.png)
as the ratio for an equally-tempered semitone (![\sqrt[12]{2}](http://upload.wikimedia.org/math/7/0/b/70b8b8fc763c20423a65bd934e378085.png)
). It was more accurate (0.44 cents sharp) than Vincenzo Galilei's 18/17 (1.05 cents flat), and could be constructed using straightedge and compass. Mersenne's description in the 1636 Harmonie universelle
of the first absolute determination of the frequency of an audible tone
(at 84 Hz) implies that he had already demonstrated that the
absolute-frequency ratio of two vibrating strings, radiating a musical
tone and its octave, is 1 : 2. The perceived harmony (consonance)
of two such notes would be explained if the ratio of the air
oscillation frequencies is also 1 : 2, which in turn is consistent with
the source-air-motion-frequency-equivalence hypothesis.
). It was more accurate (0.44 cents sharp) than Vincenzo Galilei's 18/17 (1.05 cents flat), and could be constructed using straightedge and compass. Mersenne's description in the 1636 Harmonie universelle
of the first absolute determination of the frequency of an audible tone
(at 84 Hz) implies that he had already demonstrated that the
absolute-frequency ratio of two vibrating strings, radiating a musical
tone and its octave, is 1 : 2. The perceived harmony (consonance)
of two such notes would be explained if the ratio of the air
oscillation frequencies is also 1 : 2, which in turn is consistent with
the source-air-motion-frequency-equivalence hypothesis.
He also performed extensive experiments to determine the acceleration of falling objects by comparing them with the swing of pendulums, reported in his Cogitata Physico-Mathematica in 1644.
He was the first to measure the length of the seconds pendulum, that is a pendulum whose swing takes one second, and the first to observe that a pendulum's swings are not isochronous as Galileo thought, but that large swings take longer than small swings
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Marin Mersenne, Marin Mersennus o le Père Mersenne (Oizé, 8 de septiembre de 1588 – París, 1 de septiembre de 1648) fue un filósofo francés del siglo XVII que estudió diversos campos de la teología, matemáticas y la teoría musical.
Nacido en una familia de campesinos cerca de Oizé (hoy Sarthe), en la
provincia francesa de Maine, fue educado en Le Mans y en la universidad
jesuita de La Flèche, donde conoció y frecuentó la amistad de René Descartes.
Aunque en ocasiones se afirma que fue jesuita, lo cierto es que nunca
llegó a ingresar en la Sociedad de Jesús. El 17 de julio de 1611 se hizo
miembro de los Mínimos, dedicándose al estudio de la teología y el hebreo. Después de este período recibió la orden sacerdotal en París en 1613.
Tras su consagración estuvo un tiempo enseñando filosofía y teología
en Nevers, pero en 1620 regresó a París. Allí entró en el convento de
L'Annonciade y, en compañía de personajes como Descartes, Étienne Pascal,
Gilles de Robeval y Nicholas-Claude Fabri de Peiresc, estudió
matemáticas y música. Tuvo una nutrida correspondencia con diversos
eruditos de Francia, Italia, Inglaterra y Holanda, tales como Pierre de Fermat, Galileo Galilei, Giovanni Doni y Constantijn Huygens. Desde 1620 hasta 1623 se dedicó exclusivamente a escribir en materia de filosofía y teología, y en 1623 publicó Quaestiones celeberrimae in Genesim, a la que rápidamente siguieron otras obras como L'Impieté des déistes (1624) en la que refuta las ideas de Giordano Bruno y La Vérité des sciences (1624).
Visitó Italia en tres ocasiones, en 1640, 1641 y 1645.
Más tarde, dejó el pensamiento especulativo y se dedicó a la
investigación científica, especialmente en temas como las matemáticas,
la física y la astronomía. Entre las obras relacionadas con este período
la más conocida es la traducción de L'Harmonie universelle
(1636) en la que se trata la teoría musical y los instrumentos
musicales. Una de sus mayores contribuciones a este campo fue la
sugerencia de que
era la razón principal de un semitono. Este valor era algo más afinado que el calculado por Vincenzo Galilei
en 1588 y que todavía se utiliza: 18/17. Además tenía la cualidad de
poderse construir de forma directa con una escuadra y un compás. La
descripción de Mersenne de la determinación de la primera frecuencia
absoluta de un tono audible (84 Hz)
implica que, para entonces, ya había demostrado que la razón de la
frecuencia absoluta de dos cuerdas vibrantes, que dan un tono musical y
su octava, es 1:2, y que la armonía percibida (consonancia) de tales
notas podía explicarse si la razón de las frecuencias de la oscilación
del aire también era 1:2, lo que ofrecía consistencia a la hipótesis de
la equivalencia entre las frecuencias de la fuente y el movimiento del
aire.
El Traité de l'harmonie universelle (1627) se considera la
fuente teórica de la música del siglo XVII, especialmente en Francia,
donde rivalizó incluso con las obras del gran teórico italiano Pietro
Cerone.
