Nicolas Fatio de Duillier (alternative names are Facio or Faccio) was a known for his work on the zodiacal light problem, for his role in the Newton v. Leibniz calculus controversy, and for originating the "push" or "shadow" theory of gravitation. He also developed and patented a method of perforating jewels for use in clocks.
Fatio was born as the 7th of 14 children of Jean-Baptiste and Cathérine Fatio in Basel. The family moved in 1672 to Duillier. In 1682 at the age of 18 Fatio travelled to Paris to perform astronomical studies under the astronomer Giovanni Domenico Cassini at the Parisian observatory. His greatest success was the explanation of the nature of the zodiacal light in 1684, which he attributed to particles reflecting the light of the sun.
In 1686 Fatio by chance became a witness to a conspiracy aimed at William of Orange, which he helped to foil. In the same year he made the acquaintance of Jakob Bernoulli and Christiaan Huygens, with whom a particularly close cooperation was developed. Main contents of their work were the calculus.
In 1687 he travelled to London and made the acquaintance with John Wallis and Edward Bernard (1638-1697) and worked out a solution of the inverse tangent problem. He also was friendly connected with Gilbert Burnet, John Locke, Richard Hampden and his son John Hampden. He became a fellow of the Royal Society in 1688 on the recommendation of John Hoskyns.
In 1688 he gave an account on the mechanical explanation of gravitation of Huygens before the Royal Society, whereby he tried to connect Huygens' theory with that of Newton. In 1690 he wrote a letter to Huygens, in which he outlined his own gravitational theory, which later was known as Le Sage's theory of gravitation. Soon after that he read its content before the Royal Society. This theory, on which he worked until his death, is based on minute particles which push gross matter to each other.
To optimize the capture of solar energy, and thereby plant productivity, Fatio in 1699 suggested using a tracking mechanism which could pivot to follow the Sun.
Around 1700 he and Pierre de Baufre tried to use jewels as wheel bearings in mechanical clocks. In 1705 both received a patent for that still common technology.
He had a very close relationship with Isaac Newton, and from the beginning he was impressed by Newton's gravitational theory. In 1691 he planned to prepare a new version of Newton's Philosophiae Naturalis Principia Mathematica, but never finished it. Some of Newton's biographers have suggested that the relationship may have been romantic. However, in 1694 the relationship between the two men cooled down. At this time several letter exchanges with Gottfried Wilhelm Leibniz also took place.
However, Fatio is most known by his important role at the Newton v. Leibniz calculus controversy, over who was the inventor of the calculus. He indirectly reproached Leibniz in a letter in 1699, that Leibniz has taken hold of an intellectual property not belonging to him and therefore started the quarrel.
In 1707 Fatio came under the influence of a fanatical religious sect, the Camisards, which ruined Fatio's reputation. He left England and took part in pilgrim journeys across Europe. After his return only a few scientific documents by him appeared. He died in 1753 near Worcester, England.
After his death his Geneva compatriot Georges-Louis Le Sage tried to purchase the scientific papers of Fatio. These papers together with Le Sage's are now in the Library of the University of Geneva.
A few Freudian analysts have suggested that Newton was a repressed homosexual. The main evidence is that in his middle age Newton became infatuated with Nicolas Fatio de Duillier, a disciple twenty years his junior. Gale Christianson, in his 1984 biography of Newton, In the Presence of the Creator, strongly doubts any sex activity between the pair took place, but adds:
"On the other hand, their correspondence - with its lavish praise, requited loneliness at separation, and melancholy swings of mood - bears haunting overtones of an ill-fated romance. The final break itself appears to have been prefigured in their agonizing desire to share the same chambers, a desire quite possibly overridden by the fear of what might happen if they were to attempt it."