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Francesco Maria Grimaldi

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The Rev. Dr.
Francesco Maria Grimaldi
Born(1618-04-02)2 April 1618
Died28 August 1663(1663-08-28) (aged 45)
Other names
  • Francisco Maria Grimaldo
  • Franciscus Grimaldi
Known forFree fall, diffraction
Scientific career
FieldsMathematics, Physics

Francesco Maria Grimaldi, SJ (2 April 1618 – 28 December 1663) was an Italian Jesuit priest, mathematician and physicist who taught at the Jesuit college in Bologna. He was born in Bologna to Paride Grimaldi and Anna Cattani.[1]


Between 1640 and 1650, working with Riccioli, he investigated the free fall of objects, confirming that the distance of fall was proportional to the square of the time taken. Grimaldi and Riccioli also made a calculation of gravity at the Earth's surface by recording the oscillations of an accurate pendulum.[2]

In astronomy, he built and used instruments to measure lunar mountains as well as the height of clouds, and drew an accurate map or, selenograph, which was published by Riccioli and now adorns the entrance to the National Air and Space Museum in Washington D.C.

He was the first to make accurate observations on the diffraction of light[3][4] (although by some accounts Leonardo da Vinci had earlier noted it[5]), and coined the word 'diffraction'. In his book Physico-Mathesis de Lumine, Coloribus et Iride (1665), he stated the theory of the reconstitution of sunlight from refracted coloured light. [6]

Through experimentation he was able to demonstrate that the observed passage of light could not be reconciled with the idea that it moved in a rectilinear path. Rather, the light that passed through the hole took on the shape of a cone. Later physicists used his work as evidence that light was a wave, significantly, Dutch mathematician Christiaan Huygens. He also discovered what are known as diffraction bands.[7]

The crater Grimaldi on the Moon is named after him.


He only published one work:

  • Physico-mathesis de lumine, coloribus et iride aliisque adnexis (in Latin). Girolamo Bernia: Johann Zieger. 1665.

The work is mainly remembered for being the first report of diffraction. In the work, he was mainly concerned with two questions:

  1. Is light a substance or an accident [roughly the same as "property"]?
  2. What is the relation between light and color?

He argued that light is probably a subtle fluid (thus a substance), though it might still be an accident (as Aristotelians believed). He also argued that color is associated with undulations of the subtle fluid.[8]

See also[edit]


  1. ^ Hockey, Thomas (2009). The Biographical Encyclopedia of Astronomers. Springer Publishing. ISBN 978-0-387-31022-0. Archived from the original on 2013-02-03. Retrieved August 22, 2012.
  2. ^ J.L. Heilbron, Electricity in the 17th and 18th Centuries: A Study of Early Modern Physics (Berkeley: University of California Press, 1979), 180.
  3. ^ Francesco Maria Grimaldi, Physico mathesis de lumine, coloribus, et iride, aliisque annexis libri duo (Bologna ("Bonomia"), Italy: Vittorio Bonati, 1665), pp. 1–11 (in Latin).
  4. ^ Florian Cajori (1899). A history of physics in its elementary branches: including the evolution of physical laboratories. The Macmillan Company. pp. 88–. Retrieved 14 August 2011.
  5. ^ Guglielmo Libri, Histoire des sciences mathematiques en Italie Archived 2006-11-28 at the Wayback Machine (1840)
  6. ^ David L. MacAdam (1993). Selected Papers on Colorimetry - Fundamentals. SPIE, The International Society for Optical Engineering. pp. xiv–xvi. ISBN 0-8194-1296-1.
  7. ^ Thomas E. Woods (2005). How the Catholic Church built Western civilization. Regnery Publishing. pp. 105–. ISBN 978-0-89526-038-3. Retrieved 14 August 2011.
  8. ^ Lindberg, David C. (April 1969). "Physico-mathesis de lumine, coloribus, et iride . Francesco Maria Grimaldi". Isis. 60 (1): 119. doi:10.1086/350461. ISSN 0021-1753.

External links[edit]