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Ignace Pardies, S.J.
(1636 - 1673)
and his influence on Newton

Pardies' principle of the flexible cable

Ignace G Pardies, S.J. was born in Pau, France and died in Bicetre. In his La Statique ou la science des forces mouvantes (Paris, 1673) was interested in the tension in a flexible line and was responsible for the Pardies principle found in the solution of the suspension cable. He argued that the form of a flexible line would remain unchanged if the forces at two points A and a were replaced by suitable forces acting along the tangents at A and a. This princlple was used in the later work in analyses of the catenary by Bernouli and Leibniz.

Ignace Pardies, however, made his most important scientific contribution, not in his writings, but in his correspondence. It is there that we find the objections that Pardies expressed to Newton concerning his theory of colors and the "experimentum crucis" - objections that enabled Newton to clarify certain difficult points. Pardies was a temperate and courteous critic of Newton with a vigorous intellect, as is evident from his pedagogical writings and his contacts with the pioneers of geometry. Leibniz' in particular had impression of him. Pardies intervened at a certain decisive moment in a debate between Newton and Huygens, and his important contributions in his correspondence which reflected a vigorous intellect forced Newton to clarify his thinking. New meanings emerged from beneath the Aristotelian language, and he tried to effect a compromise between Descartes and Aristotle.

The effect of the prism experiment

The Transaction of the Royal Society had many articles about this young Jesuit. The TRS performed a very important function, that of scientific reporting. It made available information communicated to only a few individuals by private correspondence. The first editor, Henry Oldenburg, had created a new field of literature, which was rapidly extended because the Transactions was the first journal to print original communications. The Jesuit historian, Conor Reilly, S.J. has collected the references to Jesuit works in the TRS for the early 17th Century, and these include some rather remarkable items. For instance, an apology to the readers was needed for ANY intercommunication with the infamous Jesuits.
Whose goal . . . is to propagate their faith, and to greaten and enrich themselves by their craft; though I deny not but some of them are also ingenious and curious in the matters of a philosophical nature; these that are so, are, I doubt not, obliged to communicate them to heretics, except they were sure they would be well requited for it.
To emphasize this point another member of the Royal Society, John Beale once wrote a letter flattering Robert Boyle for his positive influence on these impossible, obdurate men, the Jesuits. Many readers of the TRS seemed convinced that the Jesuits had vices of heroic degree and Mr. Beale would not be swayed from that conviction.
I am confident that by your philosophy you have converted these very Jesuits to make some recompense for the destruction they have so long made of mankind, that by their universal commerce, incessant industry, and bottomless purses we may receive useful intelligence and experimental formation from all parts of the world.

Some Jesuit publications were translated and presented to the Royal Society by famous people such as Robert Hooke, Robert Boyle and Samuel Johnson. Thomas Birch's History of the Royal Society gives interesting connections between Jesuits and the Royal Society and it is to the credit of the first secretary, Henry Oldenburg, that, despite his undeniable personal prejudices, he did not refrain from including accounts of the "undertakings and labors" of considerable numbers of Jesuits. Actually it would have required a special effort to neglect them, because at that time Jesuits were astonishing Europe with their geographical and intellectual discoveries. New lands were still being discovered, people were eager for information about them, and Jesuits were in the forefront of both the exploration and the articulate reporting of their findings. It was obvious that their world-wide organization of highly educated men would be in a very favorable position for sending back valuable information to Europe. Oldenburg was well aware of the possibilities and made many efforts to enlist Jesuits among his overseas correspondents. So he was pleased when Ignace Pardies wrote, showing interest in the TRS. He replied, expressing his satisfaction at the prospect of having the French Jesuit as a continental correspondent.
Especially as those of your celebrated Society (the Jesuits) have the advantage of making, by means of your international correspondence, numerous excellent and useful observations on Nature and the Arts.

Pardies challenged Newton's explanation of his experiment
thereby forcing Newton to clarify his ideas

The TRS printed critiques of Newton's theory by Robert Hooke and by the Jesuit Ignatius Pardies . . . some animadversions upon Mr Isaac Newton . . . his Theory of Light but Newton did not take it well. It is referred to in the TRS as the Newton-Hooke-Pardies debate, but it really started with the teachings of the Jesuit physicist, Francesco Maria Grimaldi. In the course of the correspondence between Pardies and Newton published in the TRS, Pardies takes his arguments from Grimaldi. Pardies had argued that such a drastic departure from the accepted theory should not be entirely founded on the one experiment of the prism since the radical implication of Newton's paper would overthrow the accepted foundations of geometrical optics. But Pardies gradually comes to Newton's position, making a rather generous admission of error, which precipitated this reply from Newton:
In the observations of Reverend Fr. Pardies, one can hardly determine whether there is more of humility and candor in allowing my arguments their due weight, or penetration and genius in stating objections.

Within a year of his reply to Newton, on April 22, 1673, Pardies, at the age of 37, died of a fever caught while ministering to prisoners at Bicetre, near Paris. His death did not go unnoticed among his correspondents in England. At the end of a review of La Statique which appeared in the TRS for May 1673, Oldenburg wrote that the book was only part of a work that Pardies had planned.
But since the publications of this part of it we understand that he hath been prevented and cut off by an untimely death; being regretted by those that knew his frankness and strong inclinations to promote philosophical knowledge. How far indeed he hath advanced these other parts of his design, and whether those of his Society, in case he hath made good progress therein, will take care to see it published.


Archivum Historicum Societatis Iesu ( AHSI ) Rome: Institutum Historicum
Bangert, William A History of the Society of Jesus. St. Louis: St. Louis Institute, 1972uis, 1810 Thomas Birch: History of the Royal Society. London: 1756 vol. 2, p. 151. Thomas Birch:The works of the honourable Robert Boyle. 5 vols. London:1744, vol. 4 p. 62.
Boyer, Carl A history of mathematics. New York: Wiley, 1968
Gillispie, Charles. C. ed., Dictionary of Scientific biography. 16 vols. New York: Charles Scribner and Sons, 1970
{ Reference to Pardies in the Dictionary of Scientific Biography is found in v 6 p130, v 7 p583, v 10 p54, 314-315. James Newman: The World of Mathematics. New York: Simon & Schuster, ed. 1956, vol. 1, p. 260.
Oldenburg, Henry ed. Philosophical Transactions of the Royal Society. vols. 1-30. London: 1665-1715
{Articles by Pardies or concerning his work are found in the Philosophical Transactions of the Royal Society of London in v 6 p3064-3066, v 7 p4087-4090, v 7 p4091-4093, v 7 p5012-5013, v 7 p5014- 5018, v 7 p4054, v 7 p5150-5151, v 8 p6042-6046, v 9 p219, v 26 p270-288.}
Reilly, Conor "A catalogue of Jesuitica in the Philosophical Transactions of the Royal Society of London" in A.H.S.I. vol. 27,1958, p. 339-362 Conor Reilly: Francis Line, S.J., an exiled English Jesuit. Rome: I H S I, 1969, pgs. 109 and 111
Sarton, GeorgeThe study of the history of mathematics. Cambridge, Mass: Harvard, 1936
Sommervogel, Carolus Bibliothèque de la compagnie de Jésus. 12 volumes. Bruxelles: Société Belge de Libraire, 1890-1960
{16 entries are found in Sommervogel; some examples are the following:
Horologium Thaumaticum Duplex (Paris, 1662)
Elemens de Géometrie (Paris, 1671)
Discours du Mouvement local (Paris, 1670)}
Clifford Truesdell: Essays on the history of mechanics. New York: Springer-Verlag, 1968, p.20.

Adventures of Some Early Jesuit Scientists

José de Acosta, S.J. - 1600: Pioneer of the Geophysical Sciences
François De Aguilon, S.J. - 1617: and his Six books on Optics
Roger Joseph Boscovich, S.J. - 1787: and his atomic theory
Christopher Clavius, S.J. - 1612: and his Gregorian Calendar
Honoré Fabri, S.J. - 1688: and his post-calculus geometry
Francesco M. Grimaldi, S.J. - 1663: and his diffraction of light
Paul Guldin, S.J. - 1643: applications of Guldin's Rule
Maximilian Hell, S.J. - 1792: and his Mesmerizing encounters
Athanasius Kircher, S.J. - 1680: The Master of a Hundred Arts
Francesco Lana-Terzi, S.J. - 1687: The Father of Aeronautics
Francis Line, S.J. - 1654: the hunted and elusive clock maker
Juan Molina, S.J. - 1829: The First Scientist of Chile
Jerôme Nadal, S.J. -1580: perspective art and composition of place
Ignace Pardies, S.J. - 1673: and his influence on Newton
Andrea Pozzo, S.J. - 1709: and his perspective geometry
Vincent Riccati, S.J. - 1775: and his hyperbolic functions
Matteo Ricci, S.J. - 1610: who brought scientific innovations to China
John Baptist Riccioli, S.J. - 167I: and his long-lived selenograph
Girolamo Saccheri, S.J. - 1733: and his solution to Euclid's blemish
Theorems of Saccheri, S.J. - 1733: and his non Euclidean Geometry
Christopher Scheiner, S.J. - 1650: sunspots and his equatorial mount
Gaspar Schott, S.J. - 1666: and the experiment at Magdeburg
Angelo Secchi, S.J. - 1878: the Father of Astrophysics
Joseph Stepling, S.J. - 1650: symbolic logic and his research academy
André Tacquet, S.J. - 1660: and his treatment of infinitesimals
Pierre Teilhard de Chardin, S. J. - 1955: and The Phenomenon of man
Ferdinand Verbiest, S.J. - 1688: an influential Jesuit scientist in China
Juan Bautista Villalpando, S.J. - 1608: and his version of Solomon's Temple
Gregory Saint Vincent, S.J. - 1667: and his polar coordinates
Nicolas Zucchi, S.J. - 1670: the renowned telescope maker

Influence of Some Early Jesuit Scientists

The 35 lunar craters named to honor Jesuit Scientists: their location and description
Post-Pombal Portugal opinion of Pre-Pombal Jesuit Scientists: a recent conference
Seismology, The Jesuit Science. a Jesuit history of geophysics

Another menu of Jesuit Interest

Jesuit history, tradition and spirituality

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