Antoine Lavoisier

Antoine-Laurent de Lavoisier

Antoine-Laurent de Lavoisier (also Antoine Lavoisier after the French Revolution; 26 August 1743 – 8 May 1794; French pronunciation: [ɑ̃twan lɔʁɑ̃ də lavwazje]) was a French nobleman and chemist central to the 18th-century chemical revolution and had a large influence on both the history of chemistry and the history of biology. He is widely considered in popular literature as the "father of modern chemistry". This label, however, is more a product of Lavoisier's

eminent skill as a self-promoter and underplays his dependence on the instruments, experiments, and ideas of other chemists

It is generally accepted that Lavoisier's great accomplishments in chemistry largely stem from his changing the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and was also the first to establish that sulfur was an element (1777) rather than a compound. He discovered that, although matter may change its form or shape, its mass always remains the same.

Lavoisier was a powerful member of a number of aristocratic councils, and an administrator of the Ferme Générale. The Ferme general was one of the most hated components of the Ancien Régime because of the profits it took at the expense of the state, the secrecy of the terms of its contracts, and the violence of its armed agentsAll of these political and economic activities enabled him to fund his scientific research. At the height of the French Revolution, he was accused by Jean-Paul Marat of selling adulterated tobacco and of other crimes, and was eventually guillotined a year after Marat's death.

Biography Early life and education

Antoine-Laurent Lavoisier was born to a wealthy family in Paris on 26 August 1743. The son of an attorney at the Parliament of Paris, he inherited a large fortune at the age of five with the passing of his mother

Lavoisier began his schooling at the Collège des Quatre-Nations,

University of Paris, (known as the Collège Mazarin) in Paris in 1754 at the age of 11. In his last two years (1760–1761) at the school, his scientific interests were aroused, and he studied chemistry, botany, astronomy, and mathematics. In the philosophy class he came under the tutelage of Abbé Nicolas Louis de Lacaille, a distinguished mathematician and observational astronomer who imbued the young Lavoisier with an interest in meteorological observation, an enthusiasm which never left him. Lavoisier entered the school of law, where he received a bachelor's degree in 1763 and a licentiate in 1764. Lavoisier received a law degree and was admitted to the bar, but never practiced as a lawyer. However, he continued his scientific education in his spare time.

Early scientific work

Lavoisier's education was filled with the ideals of the French Enlightenment of the time, and he was fascinated by Pierre Macquer's dictionary of chemistry. He attended lectures in the natural sciences. Lavoisier's devotion and passion for chemistry were largely influenced by Étienne Condillac, a prominent French scholar of the 18th century. His first chemical publication appeared in 1764. From 1763 to 1767, he studied geology under Jean-Étienne Guettard. In collaboration with Guettard, Lavoisier worked on a geological survey of Alsace-Lorraine in June 1767. In 1764 he read his first paper to the French Academy of Sciences, France's most elite scientific society, on the chemical and physical properties of gypsum (hydrated calcium sulfate), and in 1766 he was awarded a gold medal by the King for an essay on the problems of urban street lighting. In 1768 Lavoisier received a provisional

appointment to the Academy of Sciences. In 1769, he worked on the first geological map of France.

Ferme générale and marriage

Portrait of Antoine-Laurent Lavoisier and his wife by Jacques-Louis David, ca. 1788

At the age of 26, around the time he was elected to the Academy of Sciences, Lavoisier bought a share in the Ferme générale, a tax farming financial company which advanced the estimated tax revenue to the royal government in return for the right to collect the taxes. Lavoisier attempted to introduce reforms in the French monetary and taxation system to help the peasants. While in government work, he helped develop the metric system to secure uniformity of weights and measures throughout France.

Lavoisier consolidated his social and economic position when, in 1771 at age 28, he married Marie-Anne Pierrette Paulze, the 13-year-old daughter of a senior member of the Ferme générale. She was to play an important part in Lavoisier's scientific career—notably,

she translated English documents for him, including Richard Kirwan's Essay on Phlogiston and Joseph Priestley's research. In addition, she assisted him in the laboratory and created many sketches and carved engravings of the laboratory instruments used by Lavoisier and his colleagues for their scientific works.

Madame Lavoisier edited and published Antoine's memoirs (whether any English translations of those memoirs have survived is unknown as of today) and hosted parties at which eminent scientists discussed ideas and problems related to chemistry. For 3 years following his entry into the Ferme générale, Lavoisier's scientific activity diminished somewhat, for much of his time was taken up with official Ferme générale business. He did, however, present one important memoir to the Academy of Sciences during this period, on the supposed conversion of water into earth by evaporation. By a very precise quantitative experiment Lavoisier showed that the "earthy" sediment produced after long-continued reflux heating of water in a glass vessel was not due to a conversion of the water into earth but rather to the gradual disintegration of the inside of the glass vessel produced by the boiling water.

Oxygen theory of combustion

Antoine Lavoisier's famous phlogiston experiment. Engraving by Mme Lavoisier in the 1780s taken from Traité élémentaire de chimie (Elementary treatise on chemistry)

During late 1772 Lavoisier turned his attention to the phenomenon of combustion, the topic on which he was to make his most significant contribution to science. He reported the results of his first experiments on combustion in a note to the Academy on 20 October, in which he reported that when phosphorus burned, it combined with a large quantity of air to produce acid spirit of phosphorus, and that the phosphorus increased in weight on burning. In a second sealed note deposited with the Academy a few weeks later (1 November) Lavoisier extended his observations and conclusions to the burning of sulfur and went on to add that "what is observed in the combustion of sulfur and phosphorus may well take place in the case of all substances that gain in weight by combustion and calcination: and I am persuaded that the increase in weight of metallic calces is due to the same cause.

Chemical nomenclature

Lavoisier's Laboratory, Musée des Arts et Métiers, Paris.

Lavoisier and Berthollet, Chimistes Celebres, Liebig's Extract of Meat Company Trading Card, 1929

Lavoisier, together with L. B. Guyton de Morveau, Claude-Louis Berthollet, and Antoine François de Fourcroy, submitted a new program for the reforms of chemical nomenclature to the Academy in 1787, for there was virtually no rational system of chemical nomenclature at this time. The new system was tied inextricably to Lavoisier's new oxygen theory of chemistry.

The Classical elements of earth, air, fire, and water were discarded, and instead some 55 substances which could not be decomposed into simpler substances by any known chemical means were provisionally listed as elements. The elements included light; caloric (matter of heat); the principles of oxygen, hydrogen, and azote (nitrogen); carbon; sulfur; phosphorus; the yet unknown "radicals" of muriatic acid (hydrochloric acid), boracic acid, and "fluoric" acid; 17 metals; 5 earths (mainly oxides of yet unknown metals such as magnesia, barite, and strontia); three alkalies (potash, soda, and ammonia); and the "radicals" of 19 organic acids. The acids, regarded in the new system as compounds of various elements with oxygen, were given names which indicated the element involved together with the degree of oxygenation of that element, for example sulfuric and sulfurous acids, phosphoric and phosphorus acids, nitric and nitrous acids, the "ic" termination indicating acids with a higher proportion of oxygen than those with the "ous" ending. Similarly, salts of the "ic"

acids were given the terminal letters "ate," as in copper sulfate, whereas the salts of the "ous" acids terminated with the suffix "ite," as in copper sulfite. The total effect of the new nomenclature can be gauged by comparing the new name "copper sulfate" with the old term "vitriol of Venus." Lavoisier described this system of nomenclature in Méthode de nomenclature chimique (Method of Chemical Nomenclature, 1787).

Elementary Treatise of Chemistry Lavoisier employed the new nomenclature in his Traité élémentaire de chimie (Elementary Treatise on Chemistry), published in 1789. This work represents the synthesis of Lavoisier's contribution to chemistry and can be considered the first modern textbook on the subject.

The core of the work was the oxygen theory, and the work became a most effective vehicle for the transmission of the new doctrines. It presented a unified view of new theories of chemistry, contained a clear statement of the law of conservation of mass, and denied the existence of phlogiston. This text clarified the concept of an element as a substance that could not be broken down by any known method of chemical analysis, and presented Lavoisier's theory of the formation of chemical compounds from elements

It remains a classic in the history of science. While many leading chemists of the time refused to accept Lavoisier's new ideas, demand for Traité élémentaire as a textbook in Edinburgh was sufficient to merit translation into English within about a year of its French publication. In any event, the Traité élémentaire was sufficiently sound to convince the next generation.

Lavoisier conducting an experiment on respiration in the 1770s

Physiological work

Constant-pressure calorimeter, engraving made by madame Lavoisier for thermochemistry experiments

The relationship between combustion and respiration had long been recognized from the essential role which air played in both processes. Lavoisier was almost obliged, therefore, to extend his new theory of combustion to include the area of respiration physiology. His first memoirs on this topic were read to the Academy of Sciences in 1777, but his most significant contribution to this field was made in the winter of 1782/1783 in association with Laplace. The result of this work was published in a famous memoir, "On Heat." Lavoisier and Laplace designed an ice calorimeter apparatus for measuring the amount of heat given off during combustion or respiration. The outer shell of the calorimeter was packed with snow, which melted to maintain a constant temperature of 0 °C around an inner shell filled with ice.

By measuring the quantity of carbon dioxide and heat produced by confining a live guinea pig in this apparatus, and by comparing the amount of heat produced when sufficient carbon was burned in the ice calorimeter to produce the same amount of carbon dioxide as that which the guinea pig exhaled, they concluded that respiration was in fact a slow combustion process. Lavoisier stated, "la respiration est donc une

combustion," that is, respiratory gas exchange is a combustion, like that of a candle burning.

This continuous slow combustion, which they supposed took place in the lungs, enabled the living animal to maintain its body temperature above that of its surroundings, thus accounting for the puzzling phenomenon of animal heat. Lavoisier continued these respiration experiments in 1789–1790 in cooperation with Armand Seguin. They designed an ambitious set of experiments to study the whole process of body metabolism and respiration using Seguin as a human guinea pig in the experiments. Their work was only partially completed and published because of the disruption of the Revolution; but Lavoisier's pioneering work in this field served to inspire similar research on physiological processes for generations to come.

Final days and execution As the French Revolution gained momentum from 1789 on, Lavoisier's world inexorably collapsed around him. Attacks mounted on the deeply unpopular Ferme Générale, and it was eventually suppressed in 1791. In 1792 Lavoisier was forced to resign from his post on the Gunpowder Commission and to move from his house and laboratory at the Royal Arsenal. On 8 August 1793, all the learned societies, including the Academy of Sciences, were suppressed.

It is difficult to assess Lavoisier's own attitude to the political turmoil. Like so many intellectual liberals, he felt that the Ancien Régime could be reformed from the inside if only reason and moderation prevailed. Characteristically, one of his last major works was a proposal to the National Convention for the reform of French education. He tried to remain aloof from the political cockpit, no doubt fearful and uncomprehending of the violence he saw therein. However, on 24 November 1793, the arrest of all the former tax gatherers was ordered. He was branded a traitor by the Convention under Maximilien de Robespierre during the Reign of Terror, in 1794. He had also intervened

on behalf of a number of foreign-born scientists including mathematician Joseph Louis Lagrange, which helped to exempt them from a mandate stripping all foreigners of possessions and freedom. Lavoisier was tried, convicted, and guillotined on 8 May 1794 in Paris, at the age of 50, along with his 27 co-defendants.

According to a (probably apocryphal) story, the appeal to spare his life so that he could continue his experiments was cut short by the judge: "La République n'a pas besoin de savants ni de chimistes ; le cours de la justice ne peut être suspendu." ("The Republic needs neither scientists nor chemists; the course of justice cannot be delayed.") Lavoisier was convicted with summary justice of having plundered the people and the treasury of France, of having adulterated the nation's tobacco with water, and of having supplied the enemies of France with huge sums of money from the national treasury.

Lavoisier's importance to science was expressed by Joseph Louis Lagrange who lamented the beheading by saying: "Il ne leur a fallu qu’un moment pour faire tomber cette tête, et cent années peut-être ne suffiront pas pour en reproduire une semblable." ("It took them only an instant to cut off this head, and one hundred years might not suffice to reproduce its like.")

Post-mortem

Statue of Lavoisier, at Hôtel de Ville, Paris

A year and a half after his death, Lavoisier was exonerated by the French government. When his private belongings were delivered to his widow, a brief note was included, reading "To the widow of Lavoisier, who was falsely convicted"

About a century after his death, a statue of Lavoisier was erected in Paris. It was later discovered that the sculptor had not actually copied Lavoisier's head for the statue, but used a spare head of the Marquis de Condorcet, the Secretary of the Academy of Sciences during Lavoisier's last years. Lack of money prevented alterations from being made. The statue was melted down during the Second World War and has not since been replaced.

However, one of the main "lycées" (high schools) in Paris and a street in the 8th arrondissement are named after Lavoisier, and statues of him are found on the Hôtel de Ville and on the façade of the Cour Napoléon of the Louvre. His name is one of the 72 names of eminent French scientists, engineers and mathematicians inscribed on the Eiffel Tower as well as on buildings around Killian Court at MIT in Cambridge, MA US.

Lavoisier is listed among eminent Roman Catholic scientists, and as such he defended his faith against those who attempted to use science to attack it. Louis Edouard Grimaux, author of the standard French biography of Lavoisier, and the first biographer to obtain access to Lavoisier's papers, writes the following:

Raised in a pious family which had given many priests to the Church, he had held to his beliefs. To Edward King, an English author who had sent him a controversial work, he wrote, "You have done a noble thing in upholding revelation and the authenticity of the Holy Scripture, and it is remarkable that you are using for the defense precisely the same weapons which were once used for the attack".

Legacy

The work of Lavoisier was translated in Japan in the 1840s, through the process of Rangaku. Page from Udagawa Yōan's 1840 Seimi Kaisō

Lavoisier's fundamental contributions to chemistry were a result of a conscious effort to fit all experiments into the framework of a single theory. He established the consistent use of the chemical balance, used oxygen to overthrow the phlogiston theory, and developed a new system of chemical nomenclature which held that oxygen was an essential constituent of all acids (which later turned out to be erroneous). Lavoisier also did early research in physical chemistry and thermodynamics in joint experiments with Laplace. They used a calorimeter to estimate the heat evolved per unit of carbon dioxide produced, eventually finding the same ratio for a flame and animals, indicating that animals produced energy by a type of combustion reaction.

Lavoisier also contributed to early ideas on composition and chemical changes by stating the radical theory, believing that radicals, which function as a single group in a chemical process, combine with oxygen in reactions. He also introduced the possibility of allotropy in chemical elements when he discovered that diamond is a crystalline form of carbon.

He was essentially a theorist, and his great merit lay in his capacity to take over experimental work that others had carried out—without always adequately recognizing their claims—and by a rigorous logical procedure, reinforced his own quantitative experiments, expounding the true explanation of the results. He completed the work of Black, Priestley and Cavendish, and gave a correct explanation of their experiments.

Overall, his contributions are considered the most important in advancing chemistry to the level reached in physics and mathematics during the 18th century. Lavoisier's work was recognized as an International Historic Chemical Landmark by the American Chemical

Society, Académie des sciences de L'institut de France and the Société Chimique de France in 1999.