Gilles de Roberval
Encyclopedia
Gilles Personne de Roberval (August 10, 1602 – October 27, 1675), French
mathematician
, was born at Roberval, Oise
, near Beauvais, France. His name was originally Gilles Personne or Gilles Personier, that of Roberval, by which he is known, being taken from the place of his birth.
Like René Descartes
, he was present at the siege of La Rochelle
in 1627 . In the same year he went to Paris
, where he was appointed to the chair of philosophy at Gervais College in 1631, and two years later to the chair of mathematics at the Royal College of France. A condition of tenure attached to this chair was that the holder should propose mathematical questions for solution, and should resign in favour of any person who solved them better than himself; but, notwithstanding this, Roberval was able to keep the chair till his death.
Roberval was one of those mathematicians who, just before the invention of the infinitesimal calculus
, occupied their attention with problems which are only soluble, or can be most easily solved, by some method involving limits
or infinitesimal
s, which would today be solved by calculus. He worked on the quadrature
of surfaces and the cubature of solids, which he accomplished, in some of the simpler cases, by an original method which he called the "Method of Indivisibles"; but he lost much of the credit of the discovery as he kept his method for his own use, while Bonaventura Cavalieri
published a similar method
which he independently invented.
Another of Roberval’s discoveries was a very general method of drawing tangent
s, by considering a curve
as described by a moving point whose motion is the resultant of several simpler motions. He also discovered a method of deriving one curve from another, by means of which finite areas can be obtained equal to the areas between certain curves and their asymptote
s.
To these curves, which were also applied to effect some quadratures, Evangelista Torricelli
gave the name "Robervallian lines."
Between Roberval and René Descartes
there existed a feeling of ill-will, owing to the jealousy aroused in the mind of the former by the criticism that Descartes offered to some of the methods employed by him and by Pierre de Fermat
; and this led him to criticize and oppose the analytical methods that Descartes introduced into geometry about this time.
As results of Roberval’s labours outside of pure mathematics may be noted a work on the system of the universe, in which he supports the Copernican heliocentric system and attributes a mutual attraction to all particles of matter and also the invention of a special kind of balance, the Roberval Balance
.
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
, was born at Roberval, Oise
Roberval, Oise
Roberval, Oise is a small village in northern France. It is designated municipally as a commune within the département of Oise....
, near Beauvais, France. His name was originally Gilles Personne or Gilles Personier, that of Roberval, by which he is known, being taken from the place of his birth.
Like René Descartes
René Descartes
René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...
, he was present at the siege of La Rochelle
La Rochelle
La Rochelle is a city in western France and a seaport on the Bay of Biscay, a part of the Atlantic Ocean. It is the capital of the Charente-Maritime department.The city is connected to the Île de Ré by a bridge completed on 19 May 1988...
in 1627 . In the same year he went to Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
, where he was appointed to the chair of philosophy at Gervais College in 1631, and two years later to the chair of mathematics at the Royal College of France. A condition of tenure attached to this chair was that the holder should propose mathematical questions for solution, and should resign in favour of any person who solved them better than himself; but, notwithstanding this, Roberval was able to keep the chair till his death.
Roberval was one of those mathematicians who, just before the invention of the infinitesimal calculus
Infinitesimal calculus
Infinitesimal calculus is the part of mathematics concerned with finding slope of curves, areas under curves, minima and maxima, and other geometric and analytic problems. It was independently developed by Gottfried Leibniz and Isaac Newton starting in the 1660s...
, occupied their attention with problems which are only soluble, or can be most easily solved, by some method involving limits
Limit (mathematics)
In mathematics, the concept of a "limit" is used to describe the value that a function or sequence "approaches" as the input or index approaches some value. The concept of limit allows mathematicians to define a new point from a Cauchy sequence of previously defined points within a complete metric...
or infinitesimal
Infinitesimal
Infinitesimals have been used to express the idea of objects so small that there is no way to see them or to measure them. The word infinitesimal comes from a 17th century Modern Latin coinage infinitesimus, which originally referred to the "infinite-th" item in a series.In common speech, an...
s, which would today be solved by calculus. He worked on the quadrature
Quadrature (mathematics)
Quadrature — historical mathematical term which means calculating of the area. Quadrature problems have served as one of the main sources of mathematical analysis.- History :...
of surfaces and the cubature of solids, which he accomplished, in some of the simpler cases, by an original method which he called the "Method of Indivisibles"; but he lost much of the credit of the discovery as he kept his method for his own use, while Bonaventura Cavalieri
Bonaventura Cavalieri
Bonaventura Francesco Cavalieri was an Italian mathematician. He is known for his work on the problems of optics and motion, work on the precursors of infinitesimal calculus, and the introduction of logarithms to Italy...
published a similar method
Cavalieri's principle
In geometry, Cavalieri's principle, sometimes called the method of indivisibles, named after Bonaventura Cavalieri, is as follows:* 2-dimensional case: Suppose two regions in a plane are included between two parallel lines in that plane...
which he independently invented.
Another of Roberval’s discoveries was a very general method of drawing tangent
Tangent
In geometry, the tangent line to a plane curve at a given point is the straight line that "just touches" the curve at that point. More precisely, a straight line is said to be a tangent of a curve at a point on the curve if the line passes through the point on the curve and has slope where f...
s, by considering a curve
Curve
In mathematics, a curve is, generally speaking, an object similar to a line but which is not required to be straight...
as described by a moving point whose motion is the resultant of several simpler motions. He also discovered a method of deriving one curve from another, by means of which finite areas can be obtained equal to the areas between certain curves and their asymptote
Asymptote
In analytic geometry, an asymptote of a curve is a line such that the distance between the curve and the line approaches zero as they tend to infinity. Some sources include the requirement that the curve may not cross the line infinitely often, but this is unusual for modern authors...
s.
To these curves, which were also applied to effect some quadratures, Evangelista Torricelli
Evangelista Torricelli
Evangelista Torricelli was an Italian physicist and mathematician, best known for his invention of the barometer.-Biography:Evangelista Torricelli was born in Faenza, part of the Papal States...
gave the name "Robervallian lines."
Between Roberval and René Descartes
René Descartes
René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...
there existed a feeling of ill-will, owing to the jealousy aroused in the mind of the former by the criticism that Descartes offered to some of the methods employed by him and by Pierre de Fermat
Pierre de Fermat
Pierre de Fermat was a French lawyer at the Parlement of Toulouse, France, and an amateur mathematician who is given credit for early developments that led to infinitesimal calculus, including his adequality...
; and this led him to criticize and oppose the analytical methods that Descartes introduced into geometry about this time.
As results of Roberval’s labours outside of pure mathematics may be noted a work on the system of the universe, in which he supports the Copernican heliocentric system and attributes a mutual attraction to all particles of matter and also the invention of a special kind of balance, the Roberval Balance
Roberval Balance
The Roberval Balance is a weighing scale presented to the French Academy of Sciences by the French mathematician Gilles Personne de Roberval in 1669....
.