GILLES PERSONNE See also:

• GILLES PERSONNE ROBERVAL (or PERSONIER) DE (1602-1675)

ROBERVAL (or PERSONIER) DE (1602-1675)  , See also:

• FRENCH
• FRENCH, DANIEL CHESTER (1850– )
• FRENCH, NICHOLAS (1604-1678)

French mathematician, was See also:

• BORN, IGNAZ, EDLER VON (1742–1791)

born at See also:

• ROBERVAL, GILLES PERSONNE (or PERSONIER) DE (1602-1675)

Roberval, near See also:

• BEAUVAIS

Beauvais, on the 8th of See also:

• AUGUST (originally Sextilis)

August 1602 . His name was originally Gilles Personne, that of Roberval, by which he is known, being taken from the See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place of his See also:

• BIRTH (a word common in various forms to Teutonic languages from the root of the verb " to bear ")

birth . Like Rene See also:

• DESCARTES, RENE (1596-1650)

Descartes, he was See also:

• PRESENT

present at the See also:

• SIEGE (0. Fr. sege, siege, mod. siege, seat, ultimately from sedere, to sit, cf. Class. Lat. obsidium, a siege)

siege of La Rochelle in 1627 . In the same See also:

• YEAR

year he went to See also:

• PARIS
• PARIS (also called ALEXANDROS)
• PARIS, ALEXIS PAULIN (1800-x881)
• PARIS, BRUNO PAULIN GASTON (1839-1903)
• PARIS, FRANCOIS DE (169o-1727)
• PARIS, LOUIS PHILIPPE ALBERT
• PARIS, TREATIES OF (1814-1815)

Paris, where he was appointed to the See also:

• CHAIR (in. Mid. Eng. chcere, through O. Fr. chaire or chaiere, from Lat. cathedra, later caledra, Gr. xaOi3pa, seat, cf. "cathedral"; the modern Fr. form chaise, a chair, has been adopted in English with a particular meaning as a form of carriage; chaire

chair of See also:

• PHILOSOPHY (Gr. gthos, fond of, and vo4 (a, wisdom)

philosophy in the See also:

• GERVAIS, PAUL (1816-1879)

Gervais See also:

• COLLEGE (Collegium)

College in 1631, and two years later to the chair of See also:

• MATHEMATICS (Gr. /saBnµar1Kil, Sc. vOcvn or E7rlQTt'µn; from p iN.La, "learning" or "science ")

mathematics in the Royal College of See also:

• FRANCE
• FRANCE, ANATOLE (1844– )

France . A See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition of See also:

• TENURE (Fr. tenure, from Lat. tenere, to hold)

tenure attached to this chair was that the holder should propose mathematical questions for See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution, and should resign in favour of any See also:

• PERSON, OFFENCES AGAINST THE

person who solved them better than himself; but, notwithstanding this, Roberval was able to keep the chair till his See also:

• DEATH

death, which occurred at Paris on the 27th of See also:

• OCTOBER

October 1675 . Roberval was one of those mathematicians who, just before the invention of the infinitesimal calculus, occupied their See also:

• ATTENTION (from Lat. ad-tendo, await, expect; the condition of being " stretched " or " tense ")

attention with problems which are only soluble, or can be most easily solved, by some method involving limits or infinitesimals, and in the solution of which accordingly the calculus is always now employed . Thus he devoted some attention to the See also:

• QUADRATURE (from Lat. quadratura, a making square)

quadrature of surfaces and the cubature of solids, which he accomplished, in some of the simpler cases, by an See also:

• ORIGINAL

original method which he called the " Method of Indivisibles "; but he lost much of the See also:

• CREDIT (Lat. credere, to believe)

credit of the See also:

• DISCOVERY

discovery as he kept his method for his own use,while See also:

• BONAVENTURA, SAINT (JOHN OF FIDANZA)

Bonaventura Cavalieri published a similar method which he himself had invented . Another of Roberval's discoveries was a very See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general method of See also:

• DRAWING

drawing tangents, by considering a See also:

• CURVE (Lat. curvus, bent)

curve as described by a moving point whose See also:

• MOTION (Lat. motio, from movere, to move)
• MOTION, LAWS OF

motion is the resultant of several simpler motions . (See INFINITESIMAL CALCULUS.) 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 asymptotes . To these curves, which were also applied to effect some quadratures, Evangelista See also:

• TORRICELLI, EVANGELISTA (1608—1647)

Torricelli gave the name of " Robervallian lines." Between Roberval and Descartes there existed a feeling of See also:

• ILL

ill-will, owing to the See also:

• JEALOUSY (adapted from Fr. jalousie, formed from jaloux, jealous, Low Lat. zelosus, Gr. j'i os, ardour, zeal, from the root seen in '&u', to boil, ferment; cf. " yeast ")

jealousy aroused in the mind of the former by the See also:

• CRITICISM
• CRITICISM (from the Gr. KpiTrlS, a judge, Kpivew, to decide, to give an authoritative opinion)

criticism which Descartes offered to some of the methods employed by him and by See also:

• PIERRE

Pierre de See also:

• FERMAT, PIERRE DE (1601-1665)

Fermat; and this led him to criticize and oppose the See also:

• ANALYTICAL

analytical methods which Descartes introduced into See also:

• GEOMETRY

geometry about this See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time . As results of Roberval's labours out-See also:

• SIDE
• SIDE (mod. Eski Adalia)

side the See also:

• DEPARTMENT (Fr. departement, from departir, to separate into parts)

department of pure mathematics may be noted a See also:

• WORK

work on the See also:

• SYSTEM

system of the universe, in which he supports the Copernican system and attributes a mutual attraction to all particles of See also:

• MATTER

matter; and also the invention of a See also:

• SPECIAL

special See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind of See also:

• BALANCE (derived through the Fr. from the Late Lat. bilantia, an apparatus for weighing, from bi, two, and lanx, a dish or scale)

balance which goes by his name . His See also:

• WORKS

works were published in 1693 by the See also:

• ABBE (Serbo-Croatian Rai))

Abbe Gallois, in the Recited of the Memoires de l'Academie See also:

• DES

des Sciences .

See J . A . N. de C . See also:

• CONDORCET, MARIE JEAN ANTOINE NICOLAS CARITAT, MARQUIS DE (1743-1794)

Condorcet, Eloge de Roberval (Paris,' 1773): J . E . See also:

• MONTUCLA, JEAN ETIENNE (1725-1799)

Montucla, Histoire des mathematiques (1802) .