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Encyclopedia Britannica - Main :: LAP-LEO |
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LAVOISIER, ANTOINE LAURENT (1743-1794) , French chemist, was born in Paris on the 26th of August 1743. His father, an avocat au parlement, gave him an excellent education at the college Mazarin, and encouraged his taste for natural science; and he studied mathematics and astronomy with N. L. de Lacaille, chemistry with the elder Rouelle and botany with Bernard
series of posts in which his administrative abilities found full scope. Appointed regisseur des poudres in 1775, he not only abolished the vexatious search for saltpetre in the cellars of private houses, but increased the production of the salt and improved the manufacture of gunpowder. In 1785 he was nominated to the committee on agriculture, and as its secretary drew up reports and instructions on the cultivation of various crops, and promulgated schemes for the establishment of experimental agricultural stations, the distribution of agricultural implements and the adjustment of rights of pasturage. Seven years before he had started a model farm at Frechine, where he demonstrated the advantages of scientific methods of cultivation and of the introduction of good breeds of cattle and sheep. Chosen a member of the provincial assembly of Orleans in 1787, he busied himself with plans for the improvement of the social and economic conditions of the community by means of savings banks, insurance societies, canals, workhouses, &c.; and he showed the sincerity of his philanthropical work by advancing money out of- his own pocket, without interest
scheme of taxation in connexion with which he produced a report De la richesse territoriale de la France, and he was further associated with committees on hygiene, coinage, the casting of cannon, &c., and was secretary and treasurer of the commission appointed in 1790 to secure uniformity of weights and measures.In 1791, when Lavoisier was in the middle of all this official activity, the suppression of the farmers-general marked the beginning of troubles which brought about his death. His membership of that body was alone sufficient to make him an object of suspicion; his administration at the regie des poudres was attacked; and Marat accused him in the Ami du Peuple of putting Paris in prison and of stopping the circulation of air in the city by the mur d'octroi erected at his suggestion in 1787. The Academy, of which as treasurer at the time he was a con- he assigned to dephlogisticated air the name oxygen, or " acid-producer," on the supposition that all acids were formed by its union with a simple, usually non-metallic, body; and having verified this notion for phosphorus, sulphur, charcoal, &c., and even extended it to the vegetable acids, he naturally asked himself what was formed by the combustion of " inflammable air " (hydrogen). This problem he had attacked in 1774, and in subsequent years he made various attempts to discover the acid which, under the influence of his oxygen theory, he expected would be formed. It was not till the 25th of June 1783 that in conjunction with Laplace he announced to the Academy that water was the product formed by the combination of hydrogen and oxygen, but by that time he had been anticipated by Cavendish, to whose prior work, however, as to that of several other investigators in other matters, it is to be regretted that he did not render due acknowledgment. But a knowledge of the composition of water enabled him to storm the last defences of the phlogistonists. Hydrogen they held to be the phlogiston of metals, and they supported this view by pointing out that it was liberated when metals were dissolved in acids. Considerations of weight had long prevented Lavoisier from accepting this doctrine, but he was now able to explain the process fully, showing that the hydrogen evolved did not come from the metal itself, but was one product of the decomposition of the water of the dilute acid, the other product, oxygen, combining with the metal to form an oxide which in turn united with the acid. A little later this same knowledge led him to the beginnings of quantitative organic analysis. Knowing that the water produced by the combustion of alcohol was not pre-existent in that sub-stance but was formed by the combination of its hydrogen with the oxygen of the air, he burnt alcohol and other combustible organic substances, such as wax and oil, in a known volume of oxygen, and, from the weight of the water and carbon dioxide produced and his knowledge of their composition, was able to calculate the amounts of carbon, hydrogen and oxygen present in the substance. Up to about this time Lavoisier's work, mainly quantitative in character, had appealed most strongly to physicists, but it now began to win conviction from chemists also. C. L. Berthollet, L. B. Guyton de Morveau and A. F. Fourcroy, his collaborators in the reformed system of chemical terminology set forth in 1787 in the Methode de momenclature chimique, were among the earliest French converts, and they were followed by M. H. Klaproth and the German Academy, and by most English chemists except Cavendish, who rather suspended his judgment, and Priestley, who stubbornly clung to the opposite view. Indeed, though the partisans of phlogiston did not surrender without a struggle, the history of science scarcely presents a second instance of a change so fundamental accomplished with such ease. The spread of Lavoisier's doctrines was greatly facilitated by the defined and logical form in which he presented them in his Traite elementaire de chimie (presente daps un ordre nouveau et d'apres les decouvertes modernes) (1789). The list
In addition to his purely chemical work, Lavoisier, mostly in conjunction with Laplace, devoted considerable attention to physical problems, especially those connected with heat. The two carried out some of the earliest thermochemical investigations, devised apparatus for measuring linear and cubical expansions, and employed a modification of Joseph Black's ice calorimeter in a series of determinations of specific heats. Regarding heat (matiere de feu or fluide igne) as a peculiar kind of imponderable matter, Lavoisier held that the three states of aggregationsolid, liquid and gaswere modes of matter, each depending on the amount of matiere de feu with which the ponderable substances concerned were interpenetrated and combined; and this view enabled him correctly to anticipate that gases would be reduced to liquids and solids by the influence of cold and pressure. He also worked at fermentation, respiration and animal heat, looking upon the processes concerned as essentially chemical in nature. A paper discovered many years after his death showed that he had anticipated later thinkers in explaining the cyclical process of animal and vegetable life, for he pointed out that plants derive their food from the air, from water, and in general from the mineral
mineral
A complete edition of the writings of Lavoisier, Euvres de Lavoisier, publiees par les soins du ministre de l'instruction publique, was issued at Paris in six volumes from 1864-1893. This publication comprises his Opuscules physiques et chimiques (1774), many memoirs from the Academy volumes, and numerous letters, notes and reports relating to the various matters on which he was engaged. At the time of his death he was preparing an edition of his collected works, and the portions ready for the press were published in two volumes as Memoires de chimie in 18o5 by his widow (in that year married to Count Rumford), .who had drawn
See E. Grimaux, Lavoisier 1743-1794, d'apres sa correspondance, ses manuscripts, &c. (1888), which gives a list
LA VOISIN. CATHERINE MoNvolsIN, known as "La Voisin " (d. 168o), French sorceress, whose maiden name was Catherine Deshayes, was one of the chief
chief
of Mme de Montespan to poison Louis XIV. and of other crimes, planned by personages who could not be attacked without scandal which touched the throne, caused Louis XIV. to close the chambre ardente, as the court was called, on the 1st of October 1680. It was reopened on the 19th of May 1681 and sat until the 21st of July 1682. Many of the culprits escaped through private influence. Among these were Marie Anne Mancini, duchesse de Bouillon, who had sought to get rid of her husband in order to marry the duke of Vendome, though Louis XIV. banished her to Nerac. Mme de Montespan was not openly disgraced, because the preservation of Louis's own dignity was essential, and some hundred prisoners, among them the infamous Guibourg and Lesage, escaped the scaffold
See F. Ravaisson, Archives de la Bastille, vols. iv.-vii. (187o1874) ; the notes of La Reynie, preserved in the Bibliotheque Nationale; F. Funck-Brentano, Le Drame des poisons (1899); A. Masson, La Sorcellerie et la science des poisons an X VIP siecle (1904). Sardou made the affair a background for his Affaire des poisons (1907). There is a portrait of La Voisin by Antoine Coypel, which has been often reproduced. End of Article: LAVOISIER, ANTOINE LAURENT (1743-1794) If you wish, you can link directly to this article.
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