In the judgment of D'Alembert the Cartesan theory was the best that the observations of the age admitted; and " its explanation of gravity was one of the most ingenious hypotheses which philosophy ever imagined."
He first visited Paris, where he saw a good deal of d'Alembert, Diderot, Barthelemy, Raynal, Helvetius, Baron d'Holbach and others of that circle, and was often a welcome guest in the saloons of Madame Geoffrin and Madame du Deffand.
He made his first appearance in public as the critic of Newton, and the arbiter between d'Alembert and Euler.
His treatise was remarkable, not only as offering a satisfactory explanation of the coincidence between the lunar periods of rotation and revolution, but as containing the first employment of his radical formula of mechanics, obtained by combining with the principle of d'Alembert that of virtual velocities.
C. Clairault, d'Alembert, Condorcet and the Abbe Marie.
The post of director of the mathematical department of the Berlin Academy (of which he had been a member since 1759) becoming vacant by the removal of Euler to St Petersburg, the latter and d'Alembert united to recommend Lagrange as his successor.
D'Alembert, then at the height of his fame, in the hope of finding a career in Paris.
"You," said d'Alembert to him, "needed no introduction; you have recommended yourself; my support is your due."
C. Maclaurin, Legendre and d'Alembert had furnished partial solutions of the problem, confining their 1 Annales de chimie et de physique (1816), torn.
Fontenelle forms a link between two very widely different periods of French literature, that of Corneille, Racine and Boileau on the one hand, and that of Voltaire, D'Alembert and Diderot on the other.
He undoubtedly instigated D'Alembert to include a censure of the prohibition in his Encyclopedic article on "Geneva," a proceeding which provoked Rousseau's celebrated Lettre a D'Alembert sur les spectacles.
These equations were found by d'Alembert from two principles - that a rectangular canal, taken in a mass of fluid in equilibrium, is itself in equilibrium, and that a portion of the fluid, in passing from one place to another, preserves the same volume when the fluid is incompressible, or dilates itself according to a given law when the fluid is elastic. His ingenious method, published in 1752, in his Essai sur la resistance des fluides, was brought to perfection in his Opuscules mathematiques, and was adopted by Leonhard Euler.
This calculus was first applied to the motion of water by d'Alembert, and enabled both him and Euler to represent the theory of fluids in formulae restricted by no particular hypothesis.
Received at first in the ranks of the philosophes, he soon went over to their opponents, possibly more from contempt than from conviction, the immediate occasion for his change being a quarrel with d'Alembert in 1762.
Comte was as inconsolable after Madame de Vaux's death as D'Alembert after the death of Mademoiselle L'Espinasse.
Jean le Rond d'Alembert acknowledges with gratitude, that "whatever she knew of mathematics he owed to the works of Jean Bernoulli."
The problem of vibrating cords, which had been some time before resolved by Brook Taylor (1685-1731) and d'Alembert, became the subject of a long discussion conducted in a generous spirit between Bernoulli and his friend Euler.
His memoir (1775) on the rotatory motion of a body contains (as the author was aware) conclusions at variance with those arrived at by Jean le Rond, d'Alembert and Leonhard Euler in their researches on the same subject.
The publications in which Quesnay expounded his system were the following: - two articles, on "Fermiers" and on "Grains," in the Encyclopedie of Diderot and D'Alembert (1756, 1757); a discourse on the law of nature in the Physiocratie of Dupont de Nemours (1768); Maximes generale y de gouverriement economique d'un.
In 1758 appeared his Lettre a d'Alembert contre les spectacles, written in the winter of the previous year at Montlouis.
This was at once an attack on Voltaire, who was giving theatrical representations at Les Delices, on D'Alembert, who had condemned the prejudice against the stage in the Encyclopedic, and on one of the favourite amusements of the society of the day.
He also, about this time, wrote his " Recherches sur la figure des planetes," published in the Memoires of the French Academy, of which he was elected a member in succession to le Rond d'Alembert in 1783.
During forty years the resources of analysis, even in the hands of d'Alembert, Lagrange and Laplace, had not carried the theory of the attraction of ellipsoids beyond the point which the geometry of Maclaurin had reached.
Possessed of easy means and being of hospitable disposition, he kept open house for Helvetius, D'Alembert, Diderot, Condillac, Turgot, Buffon, Grimm, Hume, Garrick, Wilkes, Sterne, and for a time J.
Smith at this time lived in the society of Quesnay, Turgot, d'Alembert, Morellet, Helvetius, Marmontel and the duke de la Rochefoucauld.
Massillon enjoyed in the 18th century a reputation equal to that of Bossuet and of Bourdaloue, and has been much praised by Voltaire, D'Alembert and kindred spirits among the Encyclopaedists.
To every Salon Houdon was a chief contributor; most of the leading men of the day were his sitters; his busts of d'Alembert, Prince Henry of Prussia, Gerbier, Buffon (for Catharine of Russia) and Mirabeau are remarkable portraits; and in 1778, when the news of Rousseau's death reached him, Houdon started at once for Ermenonville, and there took a cast of the dead man's face, from which he produced the grand and life-like head now in the Louvre.
The society of Paris was peculiarly ready to receive a great philosopher and historian, especially if he were known to be an avowed antagonist of religion, and Hume made valuable friendships, especially with D'Alembert and Turgot, the latter of whom profited much by Hume's economical essays.
This error was treated by Jean le Rond d'Alembert, and, in special detail, by C. F.