Lavoisier, Antoine Laurent

Born Aug. 26, 1743, in Paris; died there May 8, 1794. French chemist; member of the Paris Academy of Sciences (1772; associate member, 1768).

Lavoisier graduated from the faculty of law at the University of Paris. He also studied the natural sciences, particularly physics and chemistry. In 1766 he was awarded a gold medal by the academy for his work in developing the best scheme for a street lighting system. In 1768–91 he amassed considerable wealth as a member of the ferme générale (an organization of financiers that collected taxes for the state), part of which he spent for the construction of a laboratory and for scientific research. He was a staunch supporter of the constitutional monarchy during the Great French Revolution. In 1794, Lavoisier and other members of the ferme générale were sentenced to death by a revolutionary tribunal and executed.

Lavoisier’s work fostered the transformation of chemistry into a science based on precise measurements. He systematically applied quantitative methods, particularly precision weighing, to the study of chemical transformations. Using the law of conservation of matter as a guide, Lavoisier disproved the erroneous phlogiston theory, which stated that all combustible substances, including metals, which are converted into “limes,” “earths,” and “cinders” upon burning, contain a source of combustibility called phlogiston, which is liberated from the substances upon burning or roasting. In 1772–77 he conducted a number of precision experiments to demonstrate the complex composition of atmospheric air and was the first to interpret correctly the phenomena of combustion and roasting as processes that involve the combination of substances with oxygen. Neither the British scientist J. Priestley nor the Swedish chemist K. Scheele was able to draw this conclusion, even though they both discovered oxygen before Lavoisier. In the words of F. Engels, “the element that was destined to overthrow all the theories on phlogiston and revolutionize chemistry was completely wasted in their hands” (K. Marx and F. Engels, Soch., 2nd ed., vol. 24, p. 19). Lavoisier, guided by the discovery of oxygen, “was the first to set the science of chemistry firmly on its feet, since it had been turned on its head in its phlogiston form” (ibid., p. 20.) In collaboration with the French military engineer J. Meusnier, Lavoisier demonstrated that water is a compound of hydrogen and oxygen (1783) and synthesized water from oxygen and hydrogen (1785). The establishment of the complex composition of water dealt the final blow to the phlogiston theory. The French mathematicians P. Laplace and G. Monge, as well as the French chemists C. Berthollet, L. Guyton de Morveau, and A. Four-croy, supported Lavoisier’s teachings.

In 1786–87, Lavoisier collaborated with the chemists mentioned above to devise a system of chemical nomenclature, which soon became universally accepted. The basic principles of the system have been preserved up to the present time. In 1789, Lavoisier and other French scientists founded the journal Annales de chimie, one of the first chemistry periodicals.

In 1789, Lavoisier published his Manual of Elementary Chemistry, in which he defined chemistry as the science of the composition of substances and their analysis. He called simple those substances that at that time could not be decomposed. They included all the nonmetals and metals, as well as “earths” and radicals, known at the time. He also classified the “hypothetical imponderables” (fluids)—light and matière de feu (heat)—as simple substances.

The trend created by Lavoisier led to the discovery of new substances and to the experimental substantiation of stoichiometric laws, which paved the way for the final introduction of atomism into the science of chemistry. Lavoisier’s views received universal recognition around the beginning of the 19th century. Academicians Ia. D. Zakharov, V. M. Severgin, and V. V. Pe-trov contributed greatly to their propagation in Russia.

Lavoisier was one of the founders of thermochemistry. In 1783 he and Laplace designed an ice calorimeter, compiled a description of the device, and conducted the first experiments to determine the heat of combustion of a number of substances. They concluded that the heat of decomposition of a compound is equal to its heat of formation. In 1777, Lavoisier proved that oxygen is absorbed and carbon dioxide is formed during the process of respiration (that is, that respiration is similar to combustion). In 1783–84, Lavoisier and Laplace established that the process of respiration is the main source of heat in animals. Lavoisier was a proponent of the materialistic views of the thinkers of the Enlightenment.