Antoine-Laurent Lavoisier
Antoine-Laurent Lavoisier (Paris, August 26, 1743 – Paris, May 8, 1794) was one of the major founders of modern chemistry. He performed experiments on the chemical reactivity of oxygen, recognizing it is a chemical element, thus rejecting the phlogiston hypothesis, and he discovered that the reaction of hydrogen with oxygen gives pure water. Lavoisier was one of the authors of the modern system for naming chemical substances. He proposed an early form of the law of conservation of mass, which later was cast into a more definite form by the British chemist John Dalton.
Having served as a tax collector before the French Revolution, he was guillotined together with 27 other tax collectors during the reign of terror.
Biography
Lavoisier was the oldest child and only son of a wealthy upper-middle class family. As a boy he showed an unusual studiousness. He went to the the prestigious Collège des Quatre-Nations, founded by Cardinal Mazarin where he was taught humanities, mathematics, and sciences. After graduation, he enrolled as a law student at the law faculty of the University of Paris. Since this study was easy for him he had much time to follow lectures on chemistry and physics and to do laboratory work under the tutelage of leading naturalists.
After obtaining his law degree in 1763, Lavoisier, like his father and his maternal grandfather before him, was admitted to the Order of Barristers, whose members presented cases before the High Court (Parlement) of Paris. However, Lavoisier did not start a law practice, but instead began pursuing scientific research that in 1768 gained him admission into one of France's most prestigious societies, the Académie des Sciences in Paris.
At the age of five Lavoisier received a considerable inheritance from his mother's estate, which he, shortly before entering the Academy of Sciences in 1768, used to purchase an interest in the Ferme générale (General Farm). The Ferme générale was, under the Ancien Régime, a franchised customs and excise operation which collected duties on behalf of the King, under 6-year contracts. The major tax collectors in that tax farming system were known as the fermiers généraux (general farmers). They collected certain sales and excise taxes, such as those on salt and tobacco. At the beginning of each financial cycle the tax farmers lent money to the government and were subsequently reimbursed through tax collections. Lavoisier spent considerable time as a tax farmer, and he was richly rewarded for his efforts. Although chemistry was Lavoisier's passion, throughout his life he devoted the majority of his time to financial and administrative affairs.
Three years after joining the General Farm, in 1771, Lavoisier married Marie Anne Paulze, the 14-year-old daughter of a colleague of the Farm. Although not educated in science, Marie Anne was an intelligent young woman. As Marie Anne and Lavoisier had no children, Marie Anne was able to devote her attentions to helping her husband in his research, and she soon became widely regarded as a valuable laboratory assistant and hostess. She knew English, which Lavoisier never did, and translated chemical works for him, for instance the works of Joseph Priestley. She employed her drawing talent to record the research conducted in the laboratory and to prepare engravings of apparatus for publications. In the laboratory she often recorded results that the experimenters dictated to her, and when Lavoisier announced his new theories she played an active role in campaigning for their acceptance. About 10 years after Lavoisier's death she married the American born Count Rumford (Benjamin Thompson).
Lavoisier also took on administrative duties within the Academy of Sciences and in other government agencies during the final years of the monarchy and the early years of the French Revolution. From 1775 to 1792 he served as a director of the French Gunpowder Administration and succeeded in making France self-sufficient in this critical military material. He developed a new method for the production of salpeter (potassium nitrate), an important ingredient of gun powder. He also conducted extensive experiments on agricultural production, advised the government on financial affairs and banking, and served on a commission whose efforts to unify weights and measures led to the adoption of the metric system.
After the revolution of 1789, Lavoisier, saw the change in power as an opportunity to rationalize and improve the nation's politics and economy. Lavoisier, being a child of the Enlightenment, valued highly the power of reason professed by the revolutionary governments. He continued to advise them on finance and science matters, and neither he nor his wife fled abroad when Maximilien Robespierre became the de facto dictator of France and the rule of terror started. Lavoisier soon found himself imprisoned along with other members of the General Farm. The Republic was being purged of its royalist past. In May 1794 Lavoisier, his father-in-law, and 26 other Tax Farmers were decapitated. Acknowledging Lavoisier's scientific stature, his contemporary, the great mathematician Joseph-Louis Lagrange, commented, "It took them only an instant to cut off that head, and a hundred years may not produce another like it."