“Chemistry, like all other sciences, had arisen from the reflections of ingenious men on general facts, which occur in the practice of the various arts of common life.”
“As dangerous as is the desire to systematize in the physical sciences, it is, nevertheless, to be feared that in storing without order a great multiplicity of experiments we observe the science rather than clarify it, render it difficult of access to those desirous of entering upon it, and finally, obtain at the price of long and tiresome work only disorder and confusion. Facts, observations, experiments—these are the materials of a great edifice, but in essembling them we must combine them into clusters, distinguish which belongs to which order and which part of the whole each pertains.”
Lavoisier in his Memoir on Combustion in General (1777)
Known as founder of modern chemistry, Lavoisier instilled in his colleagues a new aspect for quantitative techniques, the foundation of all progress in the field. While Black and Cavendish both instituted the use of careful quantitative analysis, Lavoisier succeeded in convincing other chemists of their importance. He did for chemistry what Galileo for physics: introduced sound methodology, empiricism and a quantitative approach.
Ray Spangenburgh and Diane K. Moser in History of Science In the Eighteenth Century, Universities Press (India) Limited, 1999.
Antoine Laurent Lavoisier, a ‘many-sided genius’, is regarded as founder of modern chemistry. He is one of those scientists, whose work actually led to the establishment of the foundations upon which modern science rests. When Lavoisier started working in chemistry it could hardly be called a distinct scientific discipline. While there was a large mass of empirical information but there was very little theoretical basis and it had no formal language of its own. The characteristics of metals, salts, acids and alkalis were well-known but gases were hardly known to exist. Modern chemistry was born when Lavoisier, with the help other chemists, derived his theory of combustion. While demonstrating the central role of oxygen in combustion, Lavoisier disproved the phlogiston theory. Lavoisier’s theory of combustion revolutionized the field of chemistry as a whole. He clearly demonstrated the role of oxygen in respiration of both animals and plants. He showed quantitatively the similarity between respiration and combustion. He appreciated the importance of measurements in chemistry. For making careful measurements, he got balances constructed, which were of very high precision. Lavoisier’s most sensitive Fortin balance was accurate to 1 part in 40,000. Lavoisier’s use of measurements in experiments changed chemistry from a science of observation to science of measurement. He established the composition of water and many organic compounds. He clarified the distinction between compounds and elements and provided a logical system of chemical nomenclature. He made precise measurements of the mass changes in chemical reactions. And in doing so he formulated the law of conservation of mass, that matter is neither created nor destroyed in chemical changes. Lavoisier laid the framework for understanding chemical reactions as combination of different substances. He also produced pioneering work on anatomy and physiology.
Lavoisier’s monumental achievements in chemistry constituted only one of his many activities. It is interesting to note that his public duties were so numerous that he could spare only one day in a week for scientific investigations. He performed many important administrative functions in the Royal Academy of Sciences. He made significant improvements in the manufacture of gunpowder. He wrote important papers on economics. As a member of the Temporary Commission on Weights and Measurements (1791-93), he played an important role in planning for the metric system. Lavoisier made contributions to agriculture and demonstrated the advantages of scientific farming at a model farm near Blois. In 1785 Lavoisier was appointed as secretary to the Government’s committee on agriculture. He drew up reports and instructions on the cultivation of crops. He also promulgated various agricultural schemes. He was a member of a committee concerned with social conditions of France and he developed schemes for improving public education, equitable taxation, savings banks, old age insurance and other welfare schemes. Lavoisier served on a committee that explored hospitals and prisons of Paris and then recommended remedies for their horrible state. Lavoisier worked on a scheme for improving the water supply to Paris and on a method for purifying water. During the Revolution he published a report on the state of France’s finances. He had given money without interest to the towns of Blois and Romorantin for the purchase of barley during the famine of 1788. Politically Lavoisier was a liberal. He saw the great necessity for reform in France and he worked for it but he opposed revolutionary methods.
Lavoisier was born in Paris on August 26, 1743. His father Jean-Antoine Lavoisier was a Parliamentary counsel (avocat au parlement). His mother Emilie Punctis was the daughter of a wealthy attorney. After the early death of his mother, Lavoisier was brought up by a maiden aunt. He had a happy childhood. He studied at the College Mazarin, in which he enrolled in 1754. At the College Mazarin he studied mathematics and astronomy with Nicolas de Lacaille (1713-62), chemistry with Guillaume-Francois Rouelle (1703-70) and botany with Bernard de Jussieu (1699-1786). He received an outstanding education in language, literature, science and mathematics. Following his family tradition, he pursued the study of law and he finished his education in the Faculty of Law in 1763. He obtained his license to practice law in 1764. But his inquiring mind took him to the world of science. First he studied geology (1763-67) under Jean Etienne Guettard (1715-86), who was the first to prepare a geological map of France. Lavoisier accompanied Guettard on several extensive geological trips through various regions of France. Lavoisier assisted Guettard in preparing Mineralogical Atlas and Description of France. While going through these geological trips, Lavoisier realized the close relationship between field mineralogy and the chemical analysis of minerals. He set up a laboratory in his own home. In 1765 Lavoisier published a paper on how to improve the street lighting of a large city like Paris. For this paper he received a Gold Medal from the Royal Academy of Sciences in 1766. In 1768 Lavoisier presented a paper on the analysis of water samples. Following this he was admitted to the Royal Academy of Science as adjoint-chimiste (associate chemist). In his early days Lavoisier published research papers on the Aurora Borealis, on thunder and on the composition of gypsum.
In 1768 Lavoisier became a member of a private consortium called the Fermiers Generaux (Farmers General), which had leased from the Government the right to collect some indirect taxes for six years. This was to ensure a steady income for financing his scientific investigations. Lavoisier had the wealth to invest as through his family he had became independently wealthy as early as in his early 20s. Lavoisier took his duties as tax collector very seriously and spent much time away from Paris on inspection duty. Lavoisier’s father bought him a title of nobility in 1772. In 1777 Lavoisier had purchased the country estate of Frechines near Blois.
In 1771, Lavoisier married Marie-Anne-Pierette Paulze (1758-1836). She was 14 at the time of her marriage with Lavoisier. Her father was a colleague of Lavoisier in the Farmers General. Marie Paulze’s mother was a niece of Abbe Terray, France’s Controller General of Finances and one of the most influential men of the French kingdom. Lavoisier’s marriage with Marie Paulze proved to be very successful. She was a skilled artist, engraver and painter. She studied under Louis David (1746-1825), who painted the only known portrait of Lavoisier from life. She kept laboratory records and made sketches of her husband’s experiments. She learnt English and Latin. She translated the new chemical treatises from England, which included the works of Priestley and Cavendish. Ray Spangenburg and Diane K. Moser wrote: “Lavoisier was a mover in the scientific world; although his money came to be sure, from the Fermiers Generaux, he spent it lavishly in the interest of science, and his private laboratory was a meeting place for all the major scientific figures of Europe. Thomas Jefferson and Benjamin Franklin both were warmly welcomed there. Lavoisier’s wife, Marie-Anne, who married him when she was 14, attended these meetings, illustrated them for Lavoisier’s books and was always deeply involved in his work. She translated works from English for him, took notes and participated actively.”
Lavoisier, after being appointed to the National Gunpowder Commission in 1775, shifted his residence to the Royal Arsenal of Paris. At the Arsenal, Lavoisier was in effective charge of gunpowder production and research. He was appointed as a director of the gunpowder administration (regisseur des poudres). Before Lavoisier took charge of the gunpowder administration in France, it was in a very chaotic state. He greatly improved the gunpowder, its supply and manufacture. Lavoisier abolished the vexatious search for saltpetre in the cellars of private house. He also built an excellent laboratory of his own in his home. His new home became a gathering place for scientists and freethinkers. After dinners, which used to be presided over by his wife, the guests often used to be escorted to the laboratory to witness demonstration of new experiments. One of Lavoisier’s co-workers at the Arsenal was Pierre Simon Laplace (1749-1827). Lavoisier, with the help of Laplace, extended Joseph Black’s early work on calorimetry. They developed an ingenious ice calorimeter and with this they measured heats of combustion and respiration. It was a modified version of Black’s calorimeter. This was the beginning of thermochemistry. They also derived an apparatus for measuring linear and cubical expansions. It may be noted here that Eleuthere Irenee du Pont (1771-1834) was an assistant to Lavoisier at the Arsenal. Du Pont later migrated to the USA (1800) and in 1802 he established a factory on the banks of the Brandywine River in Delware for making gunpowder. This venture of du Pont later developed into one of the world’s largest chemical concerns.
Lavoisier is best known not for his major experiments or discoveries but for his synthesis of the existing chemical knowledge. Much of Lavoisier’s work was the result of extending and coordinating the research of others. He interpreted and organized the experimental results of others and whenever necessary substantiated by his own experiments. Justus von Liebig (1803-73), the great German chemist, said that Lavoisier “discovered no new body, no new property, no natural phenomenon previously unknown. His immortal glory consists in this—he infused into the body of science a new spirit.” Lavoisier could achieve all this because he was not working as an isolated scientist. He was the focus of a school of collaboration. He was an important member of France’s Royal Academy of Sciences—the world’s most impressive assemblage of scientists. He was also an important public figure—he was at the centre of efforts to reform the French political economy.
In 1777 Lavoisier published a paper on respiration. The title of the paper was “Experiments on the respiration of animals and on the changes, which the Air undergoes in passing through the lungs.” Lavoisier demonstrated that respiration was a slow combustion or oxidation. The process of respiration used oxygen and released carbon dioxide. In his Memoir of Heat, Lavoisier wrote: “the heat released in the conversion of pure air by respiration is the principal cause of the maintenance of animal heat.”
In 1783, Lavoisier, jointly with Claude Berthollet, Antoine Francois de Fourcroy and L. B. Guyton de Morveau, published Methode de nomenclature (System of Chemical Nomenclature). It proposed new names for elements. The need for an international nomenclature consistently reflecting the composition of substances became evident to Lavoisier when he was asked to write an article on history of chemistry for an encyclopedia. Before Lavoisier the language used in chemical texts was full of inconsistencies, imprecision and double meanings. The terms used in old alchemical and chemical texts were drawn from many languages – Greek, Hebrew, Arabic and Latin. The names of chemical substances were based on a variety of analogies and impressions. A few examples of the terms used in early chemical and alchemical texts are indicated below:
Flowers of Zinc Zinc Oxide
Oil of Vitriol Sulphuric acid
Spanish Green Copper acetate
Lavoisier suggested that the elements in a compound should be reflected in its name. Based on this suggestion ‘Flowers of zinc’ became zinc oxide (a compound of zinc and oxygen) and ‘oil of vitriol’ became sulphuric acid), a compound of sulphur, oxygen and hydrogen). The new system of nomenclature proposed by Lavoisier had a provision for indicating relative proportions of the elements in a compound, for example sulphurous acid contains less oxygen than sulphuric acid.
In 1789 Lavoisier published Traite elementair de chimie (Elementary Treatise on Chemistry). Many consider it as the first textbook on modern chemistry. While Lavoisier not only designed this book for beginning students but in it he also used his own experiments and discoveries to redefine the content and practice of chemistry. It beautifully summarized Lavoisier’s main experiments and theories on which he based his movement to revolutionise chemistry. It incorporated the earlier knowledge of chemistry of salts into the new framework. In this book Lavoisier described in detail the experimental basis for his rejection of phlogiston theory in favour of his own theory of oxygen. In this book Lavoisier presented his definition of an element, as ‘the last point which analysis can reach.’ Lavoisier conclusively rejected the four-element theory, an idea that dated back to Empedocles and Aristotle. According to this theory everything was believed to be composed of earth, air, fire and water combined in different proportions. Each of these supposedly element represented different pairs of essential qualities—earth the cold and dry; water, cold and weight; fire, hot and dry; and air, hot and weight. It used to be believed that an important consequence of four-element theory was that water could be converted into earth. Lavoisier refuted this claim without any scope of doubt. The contained a list of 33 elements known at that time. His list included metallic and nonmetallic solids, earthy substances; the gases oxygen, nitrogen (then called azote), and hydrogen; and light and heat (caloric). Lavoisier’s list of elements provided the basis from which modern periodic table of elements has grown. The book had such an enormous influence on chemistry that it is compared with Newton’s Prinicipia in physics.
Lavoisier, based on his own experiments and by interpreting the experimental results obtained by others, worked out a theory of combustion. Before Lavoisier it was phlogiston theory, which explained combustion. Lavoisier also went on to show that air is a mixture of two gases—oxygen and nitrogen (he called it azote). Of course, now we know that air contains other gases also. But before Lavoisier air was considered a single substance and not a mixture. Lavoisier showed that it was oxygen which supported combustion. The phlogiston theory was the first comprehensive theory of chemistry. Its chief proponent was Georg Ernst Stahl. The term “phlogiston” was coined by Stahl from the Greek word for “inflammable.” Stahl used this term for the first time in his treatise (1697), in which he sought to distinguish combustion from fermentation. In the seventeenth century chemists generally believed that some combustible substances contain an “inflammable principle.” And when such substances burn this so called inflammable principle is released. Stahl sharpened this concept. He equated the inflammable principle or phlogiston with elementary principle, as fire was thought in those days. Phlogiston could not be obtained in isolation. Stahl reasoned that sulphur was composed of vitriolic acid and phlogiston because it could be produced by treating vitriolic acid with charcoal, a phlogiston-rich substance. Similarly metals are made of their oxides (calxes) and phlogiston as oxides could be converted back into metals by heating with charcoal. Stahl’s ideas about phlogiston came to be known as phlogiston theory. This theory stated that combustion was a loss of substance called phlogiston. And so the residue or ash was composed of the original material deprived of its phlogiston.
Phlogiston was regarded a weightless or nearly weightless substance. Though the phlogiston theory was derived from an erroneous concept it helped to explain innumerable puzzling chemical phenomena. For chemists of those days the phlogiston theory became an important means of organizing otherwise disconnected observations into a coherent body of knowledge. It stimulated all kinds of experiments on combustion, on oxidation, on respiration and on photosynthesis. While carrying out these experiments chemists came across many phenomena, which could not be explained by resorting to the phlogiston theory. It was found that when some metals were calcined, the resulting calx was heavier than the initial metal. Supporters of phlogiston theory tried to explain this phenomenon by proposing that in some metals, phlogiston had negative weight. It was found that the red precipitate of mercury (mercury oxide) could be turned back into a metal simply by heating. This implied that no phlogiston-rich source such as charcoal was needed. In spite of these problems most chemists of eighteenth century did not discard the phlogiston theory and while subscribing to this erroneous theory they made pioneering contributions particularly to the study of gases.
In a series of experiments carried out during 1772-74, Lavoisier burned phosphorus, lead, sulphur, and other elements in closed containers. While carrying out these experiments Lavoisier found that while the weight of the solid increased but the weight of the container and its contents remained same. The immediate consequence of this observation was that some part of the whole system must have lost weight. The most probable candidate for this was the air present in the vessel. Now if air lost something, a partial vacuum would exist in the closed vessel. This is because the experiment was carried out in a closed vessel. This was exactly what was found by Lavoisier. When he opened the vessel, the air rushed in to fill up the vacuum. And after this when Lavoisier weighed the container and its contents he found that the weight increased than the original. It clearly demonstrated that the formation of the oxide (or calx) was the result of the combination of air and the metal. The weight increased because of the gain of air and not due to loss of phlogiston. Lavoisier also discovered that the gas generated by heating an oxide (calx) with charcoal was nothing but fixed air earlier discovered by Joseph Black.
It was from Joseph Priestley’s experiments that Lavoisier got the idea that oxygen supported combustion. Priestley had discovered oxygen. However, he could not realize the full significance of his discovery. Lavoisier correctly interpreted the discovery made by Joseph Priestley.Even before Priestley, Pierre Bayen, an apothecary in the French army, isolated oxygen. In 1774 Bayen observed that red precipitate of mercury (mercuric oxide or HgO) produced a gas when it was heated. Bayen identified it ‘fixed air’ (CO2) earlier produced by Joseph Black. Soon after Bayen’s demonstration Priestley repeated Bayen’s experiment, probably independently. Priestley’s experiments identified the chemical nature of the gas. Priestley observed that the gas, produced by the red precipitate of mercury, supported combustion better than the normal air. As Priestley believed in phlogiston theory, he called this new air phlosisticated air. The properties of Priestley’s new air seemed to be exactly the reverse of Black’s dephlogisticated air. He also found that breathing it “peculiarly light and easy.” It may also be noted that Carl Wilhelm Scheele (1742-86), a Swedish chemist, also discovered the same gas. He called it ‘fire air’ and he postulated that fire air was part of atmospheric air. However, Scheele’s discovery was published later. Lavoisier was quick to see the significance of new findings. After knowing Priestley’s experiment, Lavoisier immediately recognized its true significance. He realized that Priestley had isolated one part of the air that supports combustion and respiration and other part of the air does not. In 1779 Lavoisier finally announced that the air is composed of two gases—one that supports combustion and the other gas does not support combustion. The part that supported combustion, Lavoisier named oxygen, a name derived from Greek roots meaning “to give rise to acids.” He thought all acids contain oxygen. Here Lavoisier was proved to be wrong later. It was one of those rare occasions when Lavoisier was wrong. Though Lavoisier proved wrong the name “oxygen” has been retained. The other gas he named “azote” again from Greek root meaning “no life”. Unlike oxygen, azote was renamed nitrogen in 1790.
Priestley lived in Leeds, a city in north England. He was a Unitarian minister. A Unitarian is a person who denies the doctrine of Trinity—the union of three divine persons Father, Son, and Holy spirit) in one Godhead and believes that God exists in one person or being. A Unitarian accepts the moral teachings, but rejects the divinity of Jesus. In his political belief Priestley was a radicalist. He supported the American colonists when in 1776 they revolted against George III (1760-1820), King of Great Britain and Ireland (1760-1820). He was against slave trade and religious bigotry. Priestley sympathised with the French Revolution. He began his scientific experiments in a local brewery of the city of Leeds. In 1780, Priestley moved to Birmingham, where he became a member of the Lunar Society. Other member of this society included Erasmus Darwin (1731-1802), James Watt and Matthew Boulton. In Birmingham, Priestley built an elaborate laboratory, which was considered by many as one of the best laboratories of that time in Europe. It may be noted that on the day of Lavoisier’s execution at the Guillotine, Priestly was forced to leave England for safety. For his support to revolutionaries in France, the rioting anti-revolutionaries burnt down his house. He spent his last ten years of his life in USA.
Thomas Kuhn in his much discussed book, The Structure of Scientific Revolution, cited Lavoisier’s revolution in chemistry as a major example of scientific revolutions and paradigm shift. While many tend to agree with Kuhn but then there are some who fail to see how Lavoisier’s chemistry provided an example to support Kuhn’s theory. Because even after Lavoisier proposed his combustion theory, chemists took a long time to abandon the phlogiston theory in favour of Lavoisier’s theory. It was certainly not a sudden change.
It was Lavoisier, who first showed that all substances can exist in the three stages of matter–solid, liquid and gas. He believed that those changes in state were the result of fire combining with matter. Lavoisier thought that the “matter of fire” or caloric, as he called it, was weightless and combined with solid to form liquid and combined with liquid to form gas. Lavoisier in his Memoir on Combustion in General published in 1777 wrote: “Undoubtedly it will not amiss to ask first what is meant by the matter of fire. I reply with Franklin, Boerhaave, and some of the philosophers of antiquity that the matter of fire or of light is a very subtle, very elastic fluid which surrounds all parts of the planet which we inhibit, which penetrates bodies composed of it with greater or less ease, and which tends when free to be in equilibrium in everything.
I will add, borrowing the language of chemistry, that this fluid is the dissolvent of a large number of bodies; that it combines with them in the same manner as water combines with salt and as acids combine with metals; and that the bodies thus combined and dissolved by the igneous fluid lose in part the properties which they had before the combination and acquire new ones which make them more like the matter of fire.”
Reign of Terror in France did not spare Lavoisier, one of the greatest scientists of all times. As a tax collector of the Government that was deposed by the revolutionary forces, many considered Lavoisier as public enemy. After all, they argued, he was member of the agency, which collected taxes from poor and downtrodden populace for an unpopular king. Lavoisier’s problem compounded when Jean-Paul Marat gained power in the revolutionary government and became a key force in the Reign of Terror that washed the streets of Paris in blood. Marat was a journalist who had early in his career pursued scientific ambition and he fancied himself a scientist. Lavoisier had condemned Marat’s worthless pamphlet Physical Researches on Fire and he had also opposed the admission of Marat to the French Academy of Sciences. Marat had never forgotten this. Lavoisier had been arrested alongwith all members of the Farmers General were arrested and thrown into prison. Though the tax collecting farm was a natural target but it affairs were in good order and the charges against its members could be refuted. But Marat wanted to punish Lavoisier. A new charge of ‘counter revolutionary activity’ was contrived which ensured a guilty verdict. In 1787, at Lavoisier’s suggestion a wall was erected was erected to stop the influx of contraband. The extremist revolutionaries charged Lavoisier of imprisoning Paris and stopping the circulation of air. In 1791 the Farmers General was abolished and not long after Lavoisier was removed from his post in gunpowder administration and he was forced to leave the arsenal. Lavoisier was arrested in November 1793. On May 08, 1794 after a trial that lasted less than a day Lavoisier was guillotined. Along with him his father in law and other members of the Farmers General were also executed. Lavoisier’s estate was confiscated, including his library and laboratory instruments. His wife Marie-Anne was also imprisoned but later released. She took refuge with a family servant. Marat who was instrumental in getting Lavoisier and other members of Farmers General convicted, himself was was arrested and guillotined before Lavoisier. But that did not help Lavoisier. It has been reported that Lavoisier requested time to complete some scientific work. His request was refused and the presiding judge was said to have answered, “The Republic has no need of scientists.” Joseph Louis Lagrange said: “It took but a moment to cut off that head: perhaps a hundred years will be required to produce another like it.”
After Lavoisier’s execution, his wife petitioned for the return of his estate. And after obtaining Lavoisier’s papers and books, she took up the task of publishing Lavoisier’s unfinished memoirs. Thus Lavoisier’s Memoires de chimie or Memoirs of Chemistry were published in two volumes in 1803. She presented copies to the important scientific societies and eminent scientists of Europe. As in the days when Lavoisier was alive, her home also became a meeting place to the leaders of science in France. Jean Baptiste Joseph Delambre (1749-1822), Baron Georges Lepold Chretien Frederic Dagobert Cuvier (1769-1832), Comte Joseph Louis Lagrange (1736-1813), Marquis Pierre Simon de Laplace (1749-1827), Pierre Eugene Marcellin Berthollet (1827-1907), Dominique Francois Jean Arago (1786-1853), Jean Baptiste Biot (1774-1862), Alexander von Humboldt (1769-1859) and others attended meetings at her home. She refused to attend those whom she thought did not use their political connections to save her husband. In 1804 Marie-Anne married Count Rumford. She kept Lavoisier’s name after her marriage to Rumford. At the time of her marriage to Rumford, she was 47 and Rumford was 50. Her second marriage did not go well and it lasted for only four years.
Lavoisier’s life ended at the whims of some lunatics but the great revolution in chemistry ushered in by him did not stop there. “With Lavoisier’s death in 1794, his part in the great revolution came to a conclusion, but progress did not end there. From the foundations laid by Lavoisier, Black, Scheele, Priestley, Cavendish and, in a way, even Stahl, chemists in the 19th century were able to build an ever-more-accurate understanding of chemical elements, their nature, how they react with one another and what processes take place in those reactions.”
1 – The History of Science in the Eighteenth Century by Ray Spangenburgh and Diane K. Moser. Hyderabad: Universities Press (India) Limited, 1999.
2 – Chambers Biographical Dictionary (Centenary Edition), edited by Melanie Parry. Edinburgh and New York: Chambers Harrap Publishers Limited, 1997.
3 – The Cambridge Dictionary of Scientists (2nd Edition) by David, Ian John & Margaret Millar. Cambridge: Cambridge University Press, 2002.
4 – A Dictionary of Scientists. Oxford and New York: Oxford University Press, 1999.
5 – The Oxford Companion to The History of Modern Science, edited by J. L. Heilborn. Oxford: Oxford University Press, 2003.
6 – The New Encyclpaedia Britannica (15th Edition). Chicago: Encyclopaedia Britannica, Inc, 1994.
7 – Antoine Lavosier : Science. Administration, and Revolution by Arthur L. Donovan, Oxford (England) and Cambridge: Massachusetts. Blackwell Science Biographies, 1993.
8 – Lavosier and the Chemistry of life : An Exploration of Scientific Creativity by Frederic Lawrence Holmes. 9 – Wisconsin Publications in the History of Science and Medicine . 4. Madison and London : University of Wisconsin Press, 1985.
9 – Revolution in Science by I Bernard Cohem. Cambridge, Massachusetts : Belknap Press of Harvard University Press, 1985
List of Illustrations
1 – Antine Laurent Lavoisier
2 – Lavoisier and is wife
3 – Antoine Lavoisier and his wife, Marie-Anne, presiding at the death of phlogiston (courtesy, Park Davis, Division of Warner-Lambert Company)
4 – Lavoisier demonstrating the composition of air (Figure: Vies des savants, 1870)
5 – An experiment in Lavoisier’s laboratory drawn by his wife.
6 – Pierre Simon Laplace
7 – E. I. Du Pont
8 – Claude Berthollet
9 – Antoine Francois de Fourcroy
10 – L. B. Guyton de Moreau
11 – Georg Ernst Stahl
12 – Joesph Priestley
13 – Joseph Black
14 – Carl Wilhelm Scheele
15 – Henry Cavendis