Mersenne

Name: Marin Mersenne

Achievements: A network of scientific contacts throughout Europe.

Born: September 8, 1588; Oize, Maine, France

Died: September 1, 1648; Paris, France (Aged 59)

Field & Discipline: Mathematics; Acoustics; Philosophy

Language: French

Father: Julien Mersenne

Mother: Jeanne Mouliere

Siblings: Unknown

Spouse: None

Children: None

Education: College of Mans (1599-1604); Jesuit College, La Fleche (1604-09);

University of the Sorbonne (1609-11)

Major Work:

“Harmonie Universelle” (1636-1637)

Life & Times:

Mersenne studied theology at the Sorbonne from 1609 to 1611, then joined the Roman Catholic Order of Minims, an order that devoted itself to prayer, study and scholarship. 

He continued his education within the order, first in Nigeon and then Meaux.  In October 1612, he returned to Paris, where he was ordained at the Place Royale, holding  his first Mass a year later.

Mersenne taught philosophy at the Minim Convent at Nevers from 1614 to 1618, and the following year he went back to Paris, to the Convent de l'Annociade near Place Royale.  There he was given the job of  “Correcteur”, or teacher, and remained there, apart from occasional visits to other western European cities, for the rest of his life.

Mersenne opposed the mystical doctrines of alchemy and astrology, and strongly supported natural science, in particular the philosophy of [supporter of] Descartes* and the astronomical theories of [supporter of] Galileo*.

In 1623, he published his first work, in which he defended orthodox theology against “deists, atheists and occultists”, in particular [attacked views of] Bruno*, whom he continued to attack in “L'Impiete des Deistes, Athees, et Libertins de ce Temps”.

Published in 1624, this work attracted the attention of the philosopher and mathematician [a pal of] Gassendi*, who met Mersenne in 1624, becoming his closest friend.

From about 1623, Mersenne’s regular visitors or correspondents came to include   [corresponded with] Peiresc*, Descartes,  [corresponded with] Roberval*, Girard Desargues, [wrote to/met ] Beeckman*, [wrote to/met ] Helmont*, [wrote to/met ] Fermat*, [wrote to/met ] Hobbes*,  [wrote to/met ]  Blaise Pascal*, and [wrote to/met] Perier*.

Mersenne's correspondence network played a major role in spreading scientific knowledge throughout Europe.  In 1625, Mersenne published “La Verité des Sciences”, a defence of the possibility of true human knowledge against rising skepticism, developed most notably by [attacked views of] Montaigne*.

The following year, he published “Synopsis Mathematica”, a collection of classical and more recent texts on mathematics and mechanics.  His “Traité d'Harmonie Universelle” in 1627 was a work on music, acoustics and instruments, a subject that he continued to work on throughout his life.

Through his extensive experiments in acoustics, Mersenne pioneered the scientific study of the upper and lower limits of audible frequencies, of harmonics, and of the measurement of the speed of sound, which he showed to be independent of pitch and strength.  He also proved that the intensity of sound, like that of light, is inversely proportional to the distance from its source.

In 1630, Mersenne went to Holland, where he visited Beeckman, Descartes and van Helmont*.  From their philosophical discussions and his own religious and scientific beliefs, Mersenne began to shape his philosophical and scientific stance.

He upheld both Catholic orthodoxy and the new mechanical concept of nature, rejecting

Renaissance Naturalism, a magical interpretation of the world, and Skepticism, which rejected the possibility of certainty in knowledge.  Central to Mersenne’s argument was his belief that mankind was denied independent rational knowledge of God's causes, that  he described as the “essence” of things.

Unlike Galileo and Descartes, who aimed at certainty in physical science, Mersenne aimed instead at experimental and quantitative precision in describing natural phenomena, as “one should not rely too much only on reasoning”.

Mersenne agreed, on the other hand, with Descartes, regarding nature as a mechanism and all living things,  with the exception of humankind, as automata, an idea he first expressed in his “Les Preludes de l'Harmonie Universelle”, in 1634.

His other publication in that year was a further investigation into acoustics, “Questions Harmoniques”, followed, two years later, with “L’Harmonie Universelle”, an important work on mathematical physics.

From the beginning of the decade, Mersenne’s interest in Galileo’s work had increased.  In support of Galileo's “Dialogo”, published in 1632, Mersenne wrote his critique “Traité des Mouvements” in 1633 and, a year later,  “Les Mechaniques de Galilee”, a version of Galileo's lectures on mechanics.

He translated parts of “Dialogo” into French, and, in 1639, published a translation of Galileo's “Discorsi”, which he called “Les Nouvelles Pensees de Galilee”.  It was through his efforts that Galileo's work became known outside Italy.

Mersenne’s interest in mathematics led him to investigate cycloids.  In 1634, a year before Galileo, he established a law stating that the frequency of a pendulum is inversely proportional to the square root of the length.  This work let him to propose to the Dutch physicist [suggested pendulum to] Christiaan Huyghens* the use of the pendulum as a timing device, inspiring the first pendulum clock, built in 1657.

Mersenne’s mathematical work is probably best remembered for his investigation of prime numbers, published in “Cogitata Physico-Mathematica” in 1644.

In the same year, Mersenne went on a visit to Italy.  When he came back to France, he studied Italian, and later French, experiments with a Torricellian vacuum tube and considered their bearing on the transmission of sound.

His thoughts on this, and on the existence of atmospheric pressure, helped to inspire the important work being carried out in England by [influenced] Boyle* and[influenced] Hooke*, on air, vacuum, combustion and respiration.

After his death a few years later, letters were found in his convent cell from 78 different correspondents, including Huyghens, Galileo, and [corresponded with] Torricelli*.

Extra Connections:  His work influenced that of economist [influenced] Sir William Petty* and hydrologist [influenced] Pierre Perrault*.

Assessment: Mersenne served as a focal point of French and European scientific thought at a critical stage in its development. At a time when formal institutions and international journals scarcely existed, he personally undertook the publication or translation of fundamental scientific treatises.

Oneliner: Marin Mersenne, 17^th century science networker

Bibliography:

• Dear, Peter, Mersenne and the Learning of the Schools, Ithaca and London, Cornell University Press, 1988.