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Antoine Lavoisier

Antoine-Laurent de Lavoisier ( ; 26 August 1743 – 8 May 1794), also Antoine Lavoisier after the French Revolution, was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.

It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely 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 named oxygen (1778), recognizing it as an element, and also recognized hydrogen as an element (1783), opposing 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 discovered that, although matter may change its form or shape, its mass always remains the same. His wife and laboratory assistant, Marie-Anne Paulze Lavoisier, became a renowned chemist in her own right.

Lavoisier was a powerful member of a number of aristocratic councils, and an administrator of the Ferme générale. The Ferme générale 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 agents. All of these political and economic activities enabled him to fund his scientific research. At the height of the French Revolution, he was charged with tax fraud and selling adulterated tobacco, and was guillotined despite appeals to spare his life in recognition of his contributions to science. A year and a half later, he was exonerated by the French government.

Early life and education
Antoine-Laurent Lavoisier was born to a wealthy family of the nobility in Paris on 26 August 1743. The son of an attorney at the Parlement of Paris, he inherited a large fortune at the age of five upon the death of his mother. Lavoisier began his schooling at the Collège des Quatre-Nations, University of Paris (also 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.

Research benefitting the public good
While Lavoisier is commonly known for his contributions to the sciences, he also dedicated a significant portion of his fortune and work toward benefitting the public. Lavoisier was a humanitarian—he cared deeply about the people in his country and often concerned himself with improving the livelihood of the population by agriculture, industry, and the sciences. The first instance of this occurred in 1765, when he submitted an essay on improving urban street lighting to the French Academy of Sciences.

Three years later in 1768, he focused on a new project to design an aqueduct. The goal was to bring water from the river Yvette into Paris so that the citizens could have clean drinking water. But, since the construction never commenced, he instead turned his focus to purifying the water from the Seine. This was the project that interested Lavoisier in the chemistry of water and public sanitation duties.

Additionally, he was interested in air quality and spent some time studying the health risks associated with gunpowder's effect on the air. In 1772, he performed a study on how to reconstruct the Hôtel-Dieu hospital, after it had been damaged by fire, in a way that would allow proper ventilation and clean air throughout.

At the time, the prisons in Paris were known to be largely unlivable and the prisoners' treatment inhumane. Lavoisier took part in investigations in 1780 (and again in 1791) on the hygiene in prisons and had made suggestions to improve living conditions, suggestions which were largely ignored.

Once a part of the Academy, Lavoisier also held his own competitions to push the direction of research towards bettering the public and his own work.

Sponsorship of the sciences
Lavoisier had a vision of public education having roots in "scientific sociability" and philanthropy.

Lavoisier gained a vast majority of his income through buying stock in the General Farm, which allowed him to work on science full-time, live comfortably, and allowed him to contribute financially to better the community. (It would also contribute to his demise during the Reign of Terror many years later. )

It was very difficult to secure public funding for the sciences at the time, and additionally not very financially profitable for the average scientist, so Lavoisier used his wealth to open a very expensive and sophisticated laboratory in France so that aspiring scientists could study without the barriers of securing funding for their research.

He also pushed for public education in the sciences. He founded two organizations, and Musée des Arts et Métiers, which were created to serve as educational tools for the public. Funded by the wealthy and noble, the Lycée regularly taught courses to the public beginning in 1793.

Ferme générale and marriage

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. On behalf of the Ferme générale Lavoisier commissioned the building of a wall around Paris so that customs duties could be collected from those transporting goods into and out of the city. His participation in the collection of its taxes did not help his reputation when the Reign of Terror began in France, as taxes and poor government reform were the primary motivators during the French Revolution.

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.

A portrait of Antoine and Marie-Anne Lavoisier was painted by the famed artist Jacques-Louis David. Completed in 1788 on the eve of the Revolution, the painting was denied a customary public display at the Paris Salon for fear that it might inflame anti-aristocratic passions.

For three 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. He also attempted to introduce reforms in the French monetary and taxation system to help the peasants.

Adulteration of tobacco
The Farmers General held a monopoly of the production, import and sale of tobacco in France, and the taxes they levied on tobacco brought revenues of 30 million livres a year. This revenue began to fall because of a growing black market in tobacco that was smuggled and adulterated, most commonly with ash and water. Lavoisier devised a method of checking whether ash had been mixed in with tobacco: "When a spirit of vitriol, aqua fortis or some other acid solution is poured on ash, there is an immediate very intense effervescent reaction, accompanied by an easily detected noise."

Lavoisier also noticed that the addition of a small amount of ash improved the flavour of tobacco. Of one vendor selling adulterated goods, he wrote "His tobacco enjoys a very good reputation in the province... the very small proportion of ash that is added gives it a particularly pungent flavour that consumers look for. Perhaps the Farm could gain some advantage by adding a bit of this liquid mixture when the tobacco is fabricated." Lavoisier also found that while adding a lot of water to bulk the tobacco up would cause it to ferment and smell bad, the addition of a very small amount improved the product.

Thereafter the factories of the Farmers General added, as he recommended, a consistent 6.3% of water by volume to the tobacco they processed. To allow for this addition, the Farmers General delivered to retailers seventeen ounces of tobacco while only charging for sixteen. To ensure that only these authorised amounts were added, and to exclude the black market, Lavoisier saw to it that a watertight system of checks, accounts, supervision and testing made it very difficult for retailers to source contraband tobacco or to improve their profits by bulking it up.

He was energetic and rigorous in implementing this, and the systems he introduced were deeply unpopular with the tobacco retailers across the country. This unpopularity was to have consequences for him during the French Revolution.

Royal Commission on Agriculture
Lavoisier urged the establishment of a Royal Commission on Agriculture. He then served as its Secretary and spent considerable sums of his own money in order to improve the agricultural yields in the Sologne, an area where farmland was of poor quality. The humidity of the region often led to a blight of the rye harvest, causing outbreaks of ergotism among the population. In 1788 Lavoisier presented a report to the Commission detailing ten years of efforts on his experimental farm to introduce new crops and types of livestock. His conclusion was that despite the possibilities of agricultural reforms, the tax system left tenant farmers with so little that it was unrealistic to expect them to change their traditional practices.

Gunpowder Commission

Lavoisier's researches on combustion were carried out in the midst of a very busy schedule of public and private duties, especially in connection with the Ferme Générale. There were also innumerable reports for and committees of the Academy of Sciences to investigate specific problems on order of the royal government. Lavoisier, whose organizing skills were outstanding, frequently landed the task of writing up such official reports. In 1775 he was made one of four commissioners of gunpowder appointed to replace a private company, similar to the Ferme Générale, which had proved unsatisfactory in supplying France with its munitions requirements. As a result of his efforts, both the quantity and quality of French gunpowder greatly improved, and it became a source of revenue for the government. His appointment to the Gunpowder Commission brought one great benefit to Lavoisier's scientific career as well. As a commissioner, he enjoyed both a house and a laboratory in the Royal Arsenal. Here he lived and worked between 1775 and 1792.

Lavoisier was a formative influence in the formation of the Du Pont gunpowder business because he trained Éleuthère Irénée du Pont, its founder, on gunpowder-making in France; the latter said that the Du Pont gunpowder mills "would never have been started but for his kindness to me."

During the Revolution
In June 1791, Lavoisier made a loan of 71,000 livres to Pierre Samuel du Pont de Nemours to buy a printing works so that du Pont could publish a newspaper, La Correspondance Patriotique. The plan was for this to include both reports of debates in the National Constituent Assembly as well as papers from the Academy of Sciences. The revolution quickly disrupted the elder du Pont's first newspaper, but his son E.I. du Pont soon launched Le Republicain and published Lavoisier's latest chemistry texts.

Lavoisier also chaired the commission set up to establish a uniform system of weights and measures which in March 1791 recommended the adoption of the metric system. The new system of weights and measures was adopted by the Convention on 1 August 1793. Lavoisier was one of the 27 Farmers General who, by order of the Convention, were all to be detained. Although temporarily going into hiding, on 30 November 1793 he handed himself into the Port Royal convent for questioning. He claimed he had not operated on this commission for many years, having instead devoted himself to science.

Lavoisier himself was removed from the commission on weights and measures on 23 December 1793, together with mathematician Pierre-Simon Laplace and several other members, for political reasons.

One of his last major works was a proposal to the National Convention for the reform of French education. He also intervened on behalf of a number of foreign-born scientists including mathematician Joseph Louis Lagrange, helping to exempt them from a mandate stripping all foreigners of possessions and freedom.

Final days and execution

As the French Revolution gained momentum, attacks mounted on the deeply unpopular Ferme générale, and it was eventually abolished in March 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 at the request of Abbé Grégoire.

On 24 November 1793, the arrest of all the former tax farmers was ordered. Lavoisier and the other Farmers General faced nine accusations of defrauding the state of money owed to it, and of adding water to tobacco before selling it. Lavoisier drafted their defense, refuting the financial accusations, reminding the court of how they had maintained a consistently high quality of tobacco. The court, however, was inclined to believe that by condemning them and seizing the goods of the Farmers General, it would recover huge sums for the state. Lavoisier was convicted and guillotined on 8 May 1794 in Paris, at the age of 50, along with his 27 co-defendants.

According to popular legend, the appeal to spare his life, in order that he could continue his experiments, was cut short by the judge, Coffinhal: "La République n'a pas besoin de savants ni de chimistes; le cours de la justice ne peut être suspendu." ("The Republic needs neither scholars nor chemists; the course of justice cannot be delayed.") The judge Coffinhal himself would be executed less than three months later, in the wake of the Thermidorian reaction.

Lavoisier's importance to science was expressed by 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.")

Exoneration
A year and a half after his execution, Lavoisier was completely exonerated by the French government. During the White Terror, his belongings were delivered to his widow. A brief note was included, reading "To the widow of Lavoisier, who was falsely convicted".

Blinking experiment
An apocryphal story exists regarding Lavoisier's execution in which the scientist blinked his eyes to demonstrate that the head retained some consciousness after being severed. Some variants of the story include Joseph-Louis Lagrange as being the scientist to observe and record Lavoisier's blinking. This story was not recorded in contemporary accounts of Lavoisier's death, and the execution site was too removed from the public for Lagrange to have viewed Lavoisier's alleged experiment. The story likely originated in a 1990s Discovery Channel documentary about guillotines and then subsequently spread online, becoming what one source describes as an urban legend.

Oxygen theory of combustion

Contrary to prevailing thought at the time, Lavoisier theorized that common air, or one of its components, combines with substances when they are burned. He demonstrated this through experiment.

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."

Joseph Black's "fixed air"
During 1773 Lavoisier determined to review thoroughly the literature on air, particularly "fixed air," and to repeat many of the experiments of other workers in the field. He published an account of this review in 1774 in a book entitled Opuscules physiques et chimiques (Physical and Chemical Essays). In the course of this review, he made his first full study of the work of Joseph Black, the Scottish chemist who had carried out a series of classic quantitative experiments on the mild and caustic alkalies. Black had shown that the difference between a mild alkali, for example, chalk (CaCO3), and the caustic form, for example, quicklime (CaO), lay in the fact that the former contained "fixed air," not common air fixed in the chalk, but a distinct chemical species, now understood to be carbon dioxide (CO2), which was a constituent of the atmosphere. Lavoisier recognized that Black's fixed air was identical with the air evolved when metal calces were reduced with charcoal and even suggested that the air which combined with metals on calcination and increased the weight might be Black's fixed air, that is, CO2.

Joseph Priestley
In the spring of 1774, Lavoisier carried out experiments on the calcination of tin and lead in sealed vessels, the results of which conclusively confirmed that the increase in weight of metals in combustion was due to combination with air. But the question remained about whether it was in combination with common atmospheric air or with only a part of atmospheric air. In October the English chemist Joseph Priestley visited Paris, where he met Lavoisier and told him of the air which he had produced by heating the red calx of mercury with a burning glass and which had supported combustion with extreme vigor. Priestley at this time was unsure of the nature of this gas, but he felt that it was an especially pure form of common air. Lavoisier carried out his own research on this peculiar substance. The result was his memoir On the Nature of the Principle Which Combines with Metals during Their Calcination and Increases Their Weight, read to the Academy on 26 April 1775 (commonly referred to as the Easter Memoir). In the original memoir, Lavoisier showed that the mercury calx was a true metallic calx in that it could be reduced with charcoal, giving off Black's fixed air in the process. When reduced without charcoal, it gave off an air which supported respiration and combustion in an enhanced way. He concluded that this was just a pure form of common air and that it was the air itself "undivided, without alteration, without decomposition" which combined with metals on calcination.

After returning from Paris, Priestley took up once again his investigation of the air from mercury calx. His results now showed that this air was not just an especially pure form of common air but was "five or six times better than common air, for the purpose of respiration, inflammation, and ... every other use of common air". He called the air dephlogisticated air, as he thought it was common air deprived of its phlogiston. Since it was therefore in a state to absorb a much greater quantity of phlogiston given off by burning bodies and respiring animals, the greatly enhanced combustion of substances and the greater ease of breathing in this air were explained.

Pioneer of stoichiometry
Lavoisier's researches included some of the first truly quantitative chemical experiments. He carefully weighed the reactants and products of a chemical reaction in a sealed glass vessel so that no gases could escape, which was a crucial step in the advancement of chemistry. In 1774, he showed that, although matter can change its state in a chemical reaction, the total mass of matter is the same at the end as at the beginning of every chemical change. Thus, for instance, if a piece of wood is burned to ashes, the total mass remains unchanged if gaseous reactants and products are included. Lavoisier's experiments supported the law of conservation of mass. In France it is taught as Lavoisier's Law and is paraphrased from a statement in his Traité Élémentaire de Chimie: "Nothing is lost, nothing is created, everything is transformed." Mikhail Lomonosov (1711–1765) had previously expressed similar ideas in 1748 and proved them in experiments; others whose ideas pre-date the work of Lavoisier include Jean Rey (1583–1645), Joseph Black (1728–1799), and Henry Cavendish (1731–1810).

Chemical nomenclature
Lavoisier, together with Louis-Bernard 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. This work, titled Méthode de nomenclature chimique (Method of Chemical Nomenclature, 1787), introduced a new system which 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 33 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), boric acid, and "fluoric" acid; 17 metals; 5 earths (mainly oxides of yet unknown metals such as magnesia, baria, 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 phosphorous 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's new nomenclature spread throughout Europe and to the United States and became common use in the field of chemistry. This marked the beginning of the anti-phlogistic approach to the field.

Chemical revolution and opposition
Lavoisier is commonly cited as a central contributor to the chemical revolution. His precise measurements and meticulous keeping of balance sheets throughout his experiment were vital to the widespread acceptance of the law of conservation of mass. His introduction of new terminology, a binomial system modeled after that of Linnaeus, also helps to mark the dramatic changes in the field which are referred to generally as the chemical revolution. Lavoisier encountered much opposition in trying to change the field, especially from British phlogistic scientists. Joseph Priestley, Richard Kirwan, James Keir, and William Nicholson, among others, argued that quantification of substances did not imply conservation of mass. Rather than reporting factual evidence, opposition claimed Lavoisier was misinterpreting the implications of his research. One of Lavoisier's allies, Jean Baptiste Biot, wrote of Lavoisier's methodology, "one felt the necessity of linking accuracy in experiments to rigor of reasoning." His opposition argued that precision in experimentation did not imply precision in inferences and reasoning. Despite opposition, Lavoisier continued to use precise instrumentation to convince other chemists of his conclusions, often results to five to eight decimal places. Nicholson, who estimated that only three of these decimal places were meaningful, stated: "If it be denied that these results are pretended to be true in the last figures, I must beg leave to observe, that these long rows of figures, which in some instances extend to a thousand times the nicety of experiment, serve only to exhibit a parade which true science has no need of: and, more than this, that when the real degree of accuracy in experiments is thus hidden from our contemplation, we are somewhat disposed to doubt whether the exactitude scrupuleuse of the experiments be indeed such as to render the proofs de l'ordre demonstratif."

Easter memoir
The "official" version of Lavoisier's Easter Memoir appeared in 1778. In the intervening period, Lavoisier had ample time to repeat some of Priestley's latest experiments and perform some new ones of his own. In addition to studying Priestley's dephlogisticated air, he studied more thoroughly the residual air after metals had been calcined. He showed that this residual air supported neither combustion nor respiration and that approximately five volumes of this air added to one volume of the dephlogisticated air gave common atmospheric air. Common air was then a mixture of two distinct chemical species with quite different properties. Thus when the revised version of the Easter Memoir was published in 1778, Lavoisier no longer stated that the principle which combined with metals on calcination was just common air but "nothing else than the healthiest and purest part of the air" or the "eminently respirable part of the air". The same year he coined the name oxygen for this constituent of the air, from the Greek words meaning "acid former". He was struck by the fact that the combustion products of such nonmetals as sulfur, phosphorus, charcoal, and nitrogen were acidic. He held that all acids contained oxygen and that oxygen was therefore the acidifying principle.

Dismantling phlogiston theory
Lavoisier's chemical research between 1772 and 1778 was largely concerned with developing his own new theory of combustion. In 1783 he read to the academy his paper entitled Réflexions sur le phlogistique (Reflections on Phlogiston), a full-scale attack on the current phlogiston theory of combustion. That year Lavoisier also began a series of experiments on the composition of water which were to prove an important capstone to his combustion theory and win many converts to it. Many investigators had been experimenting with the combination of Henry Cavendish's inflammable air, now known as hydrogen, with "dephlogisticated air" (air in the process of combustion, now known to be oxygen) by electrically sparking mixtures of the gases. All of the researchers noted Cavendish's production of pure water by burning hydrogen in oxygen, but they interpreted the reaction in varying ways within the framework of phlogiston theory. Lavoisier learned of Cavendish's experiment in June 1783 via Charles Blagden (before the results were published in 1784), and immediately recognized water as the oxide of a hydroelectric gas.

In cooperation with Laplace, Lavoisier synthesized water by burning jets of hydrogen and oxygen in a bell jar over mercury. The quantitative results were good enough to support the contention that water was not an element, as had been thought for over 2,000 years, but a compound of two gases, hydrogen and oxygen. The interpretation of water as a compound explained the inflammable air generated from dissolving metals in acids (hydrogen produced when water decomposes) and the reduction of calces by inflammable air (a combination of gas from calx with oxygen to form water).

Despite these experiments, Lavoisier's antiphlogistic approach remained unaccepted by many other chemists. Lavoisier labored to provide definitive proof of the composition of water, attempting to use this in support of his theory. Working with Jean-Baptiste Meusnier, Lavoisier passed water through a red-hot iron gun barrel, allowing the oxygen to form an oxide with the iron and the hydrogen to emerge from the end of the pipe. He submitted his findings of the composition of water to the Académie des Sciences in April 1784, reporting his figures to eight decimal places. Opposition responded to this further experimentation by stating that Lavoisier continued to draw the incorrect conclusions and that his experiment demonstrated the displacement of phlogiston from iron by the combination of water with the metal. Lavoisier developed a new apparatus which used a pneumatic trough, a set of balances, a thermometer, and a barometer, all calibrated carefully. Thirty savants were invited to witness the decomposition and synthesis of water using this apparatus, convincing many who attended of the correctness of Lavoisier's theories. This demonstration established water as a compound of oxygen and hydrogen with great certainty for those who viewed it. The dissemination of the experiment, however, proved subpar, as it lacked the details to properly display the amount of precision taken in the measurements. The paper ended with a hasty statement that the experiment was "more than sufficient to lay hold of the certainty of the proposition" of the composition of water and stated that the methods used in the experiment would unite chemistry with the other physical sciences and advance discoveries.

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.

Physiological work

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 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 Revolution's disruption, but Lavoisier's pioneering work in this field inspired similar research on physiological processes for generations.

Legacy

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 also responsible for the construction of the gasometer, an expensive instrument he used at his demonstrations. While he used his gasometer exclusively for these, he also created smaller, cheaper, more practical gasometers that worked with a sufficient degree of precision that more chemists could recreate.

Overall, his contributions are considered the most important in advancing chemistry to the level reached in physics and mathematics during the 18th century.

Following his death, a collection comprising most of his scientific manuscripts and instruments was established by his relatives at the Château de la Canière in Puy-de-Dôme.

Mount Lavoisier in New Zealand's Paparoa Range was named after him in 1970 by the Department of Scientific and Industrial Research.

Awards and honours
During his lifetime, Lavoisier was awarded a gold medal by the King of France for his work on urban street lighting (1766), and was appointed to the French Academy of Sciences (1768). He was elected as a member of the American Philosophical Society in 1775.

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. Antoine Laurent Lavoisier's Louis 1788 publication entitled Méthode de Nomenclature Chimique, published with colleagues Louis-Bernard Guyton de Morveau, Claude Louis Berthollet, and Antoine François, comte de Fourcroy, was honored by a Citation for Chemical Breakthrough Award from the Division of History of Chemistry of the American Chemical Society, presented at the Académie des Sciences (Paris) in 2015.

A number of Lavoisier Medals have been named and given in Lavoisier's honour, by organizations including the Société chimique de France, the International Society for Biological Calorimetry, and the DuPont company  He is also commemorated by the Franklin-Lavoisier Prize, marking the friendship of Antoine-Laurent Lavoisier and Benjamin Franklin. The prize, which includes a medal, is given jointly by the Fondation de la Maison de la Chimie in Paris, France and the Science History Institute in Philadelphia, PA, USA.

Selected writings

 * Opuscules physiques et chimiques (Paris: Chez Durand, Didot, Esprit, 1774). (Second edition, 1801)
 * L'art de fabriquer le salin et la potasse, publié par ordre du Roi, par les régisseurs-généraux des Poudres & Salpêtres (Paris, 1779).
 * Instruction sur les moyens de suppléer à la disette des fourrages, et d'augmenter la subsistence des bestiaux, Supplément à l'instruction sur les moyens de pourvoir à la disette des fourrages, publiée par ordre du Roi le 31 mai 1785 (Instruction on the means of compensating for the food shortage with fodder, and of increasing the subsistence of cattle, Supplement to the instruction on the means of providing for the food shortage with fodder, published by order of King on 31 May 1785).
 * (with Guyton de Morveau, Claude-Louis Berthollet, Antoine Fourcroy) Méthode de nomenclature chimique (Paris: Chez Cuchet, 1787)
 * (with Fourcroy, Morveau, Cadet, Baumé, d'Arcet, and Sage) Nomenclature chimique, ou synonymie ancienne et moderne, pour servir à l'intelligence des auteurs. (Paris: Chez Cuchet, 1789)
 * Traité élémentaire de chimie, présenté dans un ordre nouveau et d'après les découvertes modernes (Paris: Chez Cuchet, 1789; Bruxelles: Cultures et Civilisations, 1965) (lit. Elementary Treatise on Chemistry, presented in a new order and alongside modern discoveries) also here
 * (with Pierre-Simon Laplace) "Mémoire sur la chaleur," Mémoires de l'Académie des sciences (1780), pp. 355–408.
 * Mémoire contenant les expériences faites sur la chaleur, pendant l'hiver de 1783 à 1784, par P.S. de Laplace & A. K. Lavoisier (1792)
 * Mémoires de Physique et de Chimie, de la Société d'Arcueil (1805: posthumous)

In translation

 * Essays Physical and Chemical (London: for Joseph Johnson, 1776; London: Frank Cass and Company Ltd., 1970) translation by Thomas Henry of Opuscules physiques et chimiques
 * The Art of Manufacturing Alkaline Salts and Potashes, Published by Order of His Most Christian Majesty, and approved by the Royal Academy of Sciences (1784) trans. by Charles Williamos of L'art de fabriquer le salin et la potasse
 * (with Pierre-Simon Laplace) Memoir on Heat: Read to the Royal Academy of Sciences, 28 June 1783, by Messrs. Lavoisier & De La Place of the same Academy. (New York: Neale Watson Academic Publications, 1982) trans. by Henry Guerlac of Mémoire sur la chaleur
 * Essays, on the Effects Produced by Various Processes On Atmospheric Air; With A Particular View To An Investigation Of The Constitution Of Acids, trans. Thomas Henry (London: Warrington, 1783) collects these essays:
 * 1) "Experiments on the Respiration of Animals, and on the Changes effected on the Air in passing through their Lungs." (Read to the Académie des Sciences, 3 May 1777)
 * 2) "On the Combustion of Candles in Atmospheric Air and in Dephlogistated Air." (Communicated to the Académie des Sciences, 1777)
 * 3) "On the Combustion of Kunckel's Phosphorus."
 * 4) "On the Existence of Air in the Nitrous Acid, and on the Means of decomposing and recomposing that Acid."
 * 5) "On the Solution of Mercury in Vitriolic Acid."
 * 6) "Experiments on the Combustion of Alum with Phlogistic Substances, and on the Changes effected on Air in which the Pyrophorus was burned."
 * 7) "On the Vitriolisation of Martial Pyrites."
 * 8) "General Considerations on the Nature of Acids, and on the Principles of which they are composed."
 * 9) "On the Combination of the Matter of Fire with Evaporable Fluids; and on the Formation of Elastic Aëriform Fluids."
 * “Reflections on Phlogiston”, translation by Nicholas W. Best of “Réflexions sur le phlogistique, pour servir de suite à la théorie de la combustion et de la calcination” (read to the Académie Royale des Sciences over two nights, 28 June and 13 July 1783). Published in two parts:
 * Method of chymical nomenclature: proposed by Messrs. De Moreau, Lavoisier, Bertholet, and De Fourcroy (1788) Dictionary
 * Elements of Chemistry, in a New Systematic Order, Containing All the Modern Discoveries (Edinburgh: William Creech, 1790; New York: Dover, 1965) translation by Robert Kerr of Traité élémentaire de chimie. ISBN 978-0-486-64624-4 (Dover).
 * 1799 edition
 * 1802 edition: volume 1, volume 2
 * Some illustrations from 1793 edition
 * Some more illustrations from the Science History Institute
 * More illustrations (from Collected Works) from the Science History Institute
 * Some more illustrations from the Science History Institute
 * More illustrations (from Collected Works) from the Science History Institute

authors: نوفاك اتشمان

title: Antoine Lavoisier


text:
Hermann Kolbe

Adolph Wilhelm Hermann Kolbe (27 September 1818 – 25 November 1884 ) was a major contributor to the birth of modern organic chemistry. He was a professor at Marburg and Leipzig. Kolbe was the first to apply the term synthesis in a chemical context, and contributed to the philosophical demise of vitalism through synthesis of the organic substance acetic acid from carbon disulfide, and also contributed to the development of structural theory. This was done via modifications to the idea of "radicals" and accurate prediction of the existence of secondary and tertiary alcohols, and to the emerging array of organic reactions through his Kolbe electrolysis of carboxylate salts, the Kolbe-Schmitt reaction in the preparation of aspirin and the Kolbe nitrile synthesis. After studies with Wöhler and Bunsen, Kolbe was involved with the early internationalization of chemistry through work in London (with Frankland). He was elected to the Royal Swedish Academy of Sciences, and won the Royal Society of London's Davy Medal in the year of his death. Despite these accomplishments and his training important members of the next generation of chemists (including Zaitsev, Curtius, Beckmann, Graebe, Markovnikov, and others), Kolbe is best remembered for editing the Journal für Praktische Chemie for more than a decade, in which his vituperative essays on Kekulé's structure of benzene, van't Hoff's theory on the origin of chirality and Baeyer's reforms of nomenclature were personally critical and linguistically violent. Kolbe died of a heart attack in Leipzig at age 66, six years after the death of his wife, Charlotte. He was survived by four children.

Life
Kolbe was born in Elliehausen, near Göttingen, Kingdom of Hanover (Germany) as the eldest son of a Protestant pastor. At the age of 13, he entered the Göttingen Gymnasium, residing at the home of one of the professors. He obtained the leaving certificate (the Abitur) six years later. He had become passionate about the study of chemistry, matriculating at the University of Göttingen in the spring of 1838 in order to study with the famous chemist Friedrich Wöhler.

In 1842, he became an assistant to Robert Bunsen at the Philipps-Universität Marburg. He took his doctoral degree in 1843 at the same university. A new opportunity arose in 1845, when he became assistant to Lyon Playfair at the new Museum of Economic Geology in London and a close friend of Edward Frankland. From 1847, he was engaged in editing the Handwörterbuch der reinen und angewandten Chemie (Dictionary of Pure and Applied Chemistry) edited by Justus von Liebig, Wöhler, and Johann Christian Poggendorff, and he also wrote an important textbook. In 1851, Kolbe succeeded Bunsen as professor of chemistry at Marburg and, in 1865, he was called to the Universität Leipzig. In 1864, he was elected a foreign member of the Royal Swedish Academy of Sciences. He was elected as a member of the American Philosophical Society in 1874.

In 1853, he married Charlotte, the daughter of General-Major Wilhelm von Bardeleben. His wife died in 1876 after 23 years of happy marriage. They had four children.

Work in chemical research
As late as the 1840s, and despite Friedrich Wöhler's synthesis of urea in 1828, some chemists still believed in the doctrine of vitalism, according to which a special life-force was necessary to create "organic" (i.e., in its original meaning, biologically derived) compounds. Kolbe promoted the idea that organic compounds could be derived from substances clearly sourced from outside this "organic" context, directly or indirectly, by substitution processes. (Hence, while by modern definitions, he was converting one organic molecule to another, by the parlance of his era, he was converting "inorganic"—anorganisch—substances into "organic" ones only thought accessible through vital processes.) He validated his theory by converting carbon disulfide (CS2) to acetic acid (CH3COOH) in several steps (1843–45). Kolbe also introduced a modified idea of structural radicals, so contributing to the development of structural theory. A dramatic success came when his theoretical prediction of the existence of secondary and tertiary alcohols was confirmed by the synthesis of the first of these classes of organic molecules. Kolbe was the first person to use the word synthesis in its present-day meaning, and contributed a number of new chemical reactions.

In particular, Kolbe developed procedures for the electrolysis of the salts of fatty and other carboxylic acids (Kolbe electrolysis) and prepared salicylic acid, a building block of aspirin in a process called Kolbe synthesis or Kolbe-Schmitt reaction. His method for the synthesis of nitriles is called the Kolbe nitrile synthesis, and with Edward Frankland he found that nitriles can be hydrolyzed to the corresponding acids. In addition to his own bench research and scholarly and editorial work, Kolbe oversaw student research at Leipzig and especially at Marburg; students spending time under his tutelage included Peter Griess, Aleksandr Mikhailovich Zaitsev (known for Zaitsev's rule predicting the product composition of elimination reactions), Theodor Curtius (discoverer of diazo compounds, hydrazines, and the Curtius rearrangement), Ernst Otto Beckmann (discoverer of the Beckmann rearrangement), Carl Graebe (discoverer of alizarin), Oscar Loew, Constantin Fahlberg, Nikolai Menshutkin, Vladimir Markovnikov (first to describe carbocycles smaller and larger than cyclohexane, and known for Markovnikov's rule describing addition reactions to alkenes), Jacob Volhard, Ludwig Mond, Alexander Crum Brown (first to describe the double bond of ethylene), Maxwell Simpson, and Frederick Guthrie.

Work as journal editor
Besides his work for periodicals he wrote numerous books Kolbe served for more than a decade as what, in modern terms, would be understood the senior editor of the Journal für Praktische Chemie (Journal of practical chemistry, from 1870 to 1884), Kolbe was sometimes so severely critical of the work of others, especially after about 1874, that some wondered whether he might have been suffering a mental illness. He was intolerant of what he regarded as loose speculation parading as theory, and sought through his writings to save his beloved science of chemistry from what he regarded as the scourge of modern structural theory.

His rejection of structural chemistry, especially the theories of the structure of benzene by August Kekulé, the theory of the asymmetric carbon atom by J.H. van't Hoff, and the reform of chemical nomenclature by Adolf von Baeyer, was expressed in his vituperative articles in the Journal für Praktische Chemie. Some translated quotes illustrate his manner of articulating the deep conflict between his interpretation of chemistry and that of the structural chemists: "«...Baeyer is an excellent experimentor, but he is only an empiricist, lacking sense and capability, and his interpretations of his experiments show particular deficiency in his familiarity with the principles of true science...»"The violence of his language worked to limit his posthumous reputation.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Hermann Kolbe


text:
April 18

Pre-1600

 * 796 – King Æthelred I of Northumbria is murdered in Corbridge by a group led by his ealdormen, Ealdred and Wada. The patrician Osbald is crowned, but abdicates within 27 days.
 * 1428 – Peace of Ferrara between Republic of Venice, Duchy of Milan, Republic of Florence and House of Gonzaga: ending of the second campaign of the Wars in Lombardy fought until the Treaty of Lodi in 1454, which will then guarantee the conditions for the development of the Italian Renaissance.
 * 1506 – The cornerstone of the current St. Peter's Basilica is laid.
 * 1518 – Bona Sforza is crowned as queen consort of Poland.
 * 1521 – Trial of Martin Luther begins its second day during the assembly of the Diet of Worms. He refuses to recant his teachings despite the risk of excommunication.

1601–1900

 * 1689 – Bostonians rise up in rebellion against Sir Edmund Andros.
 * 1738 – Real Academia de la Historia ("Royal Academy of History") is founded in Madrid.
 * 1775 – American Revolution: The British advancement by sea begins; Paul Revere and other riders warn the countryside of the troop movements.
 * 1783 – Three-Fifths Compromise: The first instance of black slaves in the United States of America being counted as three fifths of persons (for the purpose of taxation), in a resolution of the Congress of the Confederation. This was later adopted in the 1787 Constitution.
 * 1831 – The University of Alabama is founded in Tuscaloosa, Alabama.
 * 1847 – American victory at the battle of Cerro Gordo opens the way for invasion of Mexico.
 * 1857 – "The Spirits Book" by Allan Kardec is published, marking the birth of Spiritualism in France.
 * 1864 – Battle of Dybbøl: A Prussian-Austrian army defeats Denmark and gains control of Schleswig. Denmark surrenders the province in the following peace settlement.
 * 1897 – The Greco-Turkish War is declared between Greece and the Ottoman Empire.
 * 1899 – The St. Andrew's Ambulance Association is granted a royal charter by Queen Victoria.

1901–present

 * 1902 – The 7.5 Guatemala earthquake shakes Guatemala with a maximum Mercalli intensity of VIII (Severe), killing between 800 and 2,000.
 * 1906 – The 7.9 earthquake and fire destroy much of San Francisco, California, killing more than 3,000 people, making one of the worst natural disasters in American history.
 * 1909 – Joan of Arc is beatified in Rome.
 * 1912 – The Cunard liner RMS Carpathia brings 705 survivors from the RMS Titanic to New York City.
 * 1915 – World War I: French pilot Roland Garros is shot down and glides to a landing on the German side of the lines.
 * 1916 – World War I: During a mine warfare in high altitude on the Dolomites, the Italian troops conquer the Col di Lana held by the Austrian army.
 * 1930 – A fire kills 118 people at a wooden church in the small Romanian town of Costești, most of them schoolchildren, after starting during Good Friday services.
 * 1939 – Robert Menzies, who became Australia's longest-serving prime minister, is elected as leader of the United Australia Party after the death of Prime Minister Joseph Lyons.
 * 1942 – World War II: The Doolittle Raid on Japan: Tokyo, Yokohama, Kobe and Nagoya are bombed.
 * 1942  – Pierre Laval becomes Prime Minister of Vichy France.
 * 1943 – World War II: Operation Vengeance, Admiral Isoroku Yamamoto is killed when his aircraft is shot down by U.S. fighters over Bougainville Island.
 * 1945 – World War II: Over 1,000 bombers attack the small island of Heligoland, Germany.
 * 1945  – Italian resistance movement: In Turin, despite the harsh repressive measures adopted by Nazi-fascists, a great pre-insurrectional strike begins.
 * 1946 – The International Court of Justice holds its inaugural meeting in The Hague, Netherlands.

 * 1946 – Jackie Robinson makes his regular season debut for the Montreal Royals of the International League, to make them the first integrated modern professional baseball team.
 * 1947 – The Operation Big Bang, the largest non-nuclear man-made explosion to that time, destroys bunkers and military installations on the North Sea island of Heligoland, Germany.
 * 1949 – The Republic of Ireland Act comes into force, declaring Éire to be a republic and severing Ireland "association" with the Commonwealth of Nations.
 * 1954 – Gamal Abdel Nasser seizes power in Egypt.
 * 1955 – Twenty-nine nations meet at Bandung, Indonesia, for the first Asian-African Conference.
 * 1972 – East African Airways Flight 720 crashes during a rejected takeoff from Addis Ababa Bole International Airport in Addis Ababa, Ethiopia, killing 43.
 * 1980 – The Republic of Zimbabwe (formerly Rhodesia) comes into being, with Canaan Banana as the country's first President. The Zimbabwean dollar replaces the Rhodesian dollar as the official currency.
 * 1980 – The town of Elmore City, Oklahoma holds its first dance in the town’s history.
 * 1988 – The United States launches Operation Praying Mantis against Iranian naval forces in the largest naval battle since World War II.
 * 1988  – In Israel John Demjanjuk is sentenced to death for war crimes committed in World War II, although the verdict is later overturned.
 * 2018 – King Mswati III of Swaziland announces that his country's name will change to Eswatini.
 * 2018  – Anti-government protests start in Nicaragua.
 * 2019 – A redacted version of the Mueller report is released to the United States Congress and the public.

Pre-1600

 * 359 – Gratian, Roman emperor (d. 383)
 * 588 – K'an II, Mayan ruler (d. 658)
 * 812 – Al-Wathiq, Abbasid caliph (d. 847)
 * 1446 – Ippolita Maria Sforza, Italian noble (d. 1484)
 * 1480 – Lucrezia Borgia, daughter of Pope Alexander VI (d. 1519)
 * 1503 – Henry II of Navarre (d. 1555)
 * 1534 – William Harrison, English clergyman (d. 1593)
 * 1580 – Thomas Middleton, English Jacobean playwright and poet (d. 1627)
 * 1590 – Ahmed I, Ottoman Emperor (d. 1617)

1601–1900

 * 1605 – Giacomo Carissimi, Italian priest and composer (d. 1674)
 * 1666 – Jean-Féry Rebel, French violinist and composer (d. 1747)
 * 1740 – Sir Francis Baring, 1st Baronet, English banker and politician (d. 1810)
 * 1759 – Jacques Widerkehr, French cellist and composer (d. 1823)
 * 1771 – Karl Philipp, Prince of Schwarzenberg (d. 1820)
 * 1772 – David Ricardo, British economist and politician (d. 1823)
 * 1794 – William Debenham, English founder of Debenhams (d. 1863)
 * 1813 – James McCune Smith, African-American physician, apothecary, abolitionist, and author (d. 1865)
 * 1819 – Carlos Manuel de Céspedes, Cuban lawyer and activist (d. 1874)
 * 1819  – Franz von Suppé, Austrian composer and conductor (d. 1895)
 * 1838 – Paul-Émile Lecoq de Boisbaudran, French chemist and academic (d. 1912)
 * 1854 – Ludwig Levy, German architect (d. 1907)
 * 1857 – Clarence Darrow, American lawyer (d. 1938)
 * 1858 – Dhondo Keshav Karve, Indian educator and activist, Bharat Ratna Awardee (d. 1962)
 * 1858  – Alexander Shirvanzade, Armenian playwright and author (d. 1935)
 * 1863 – Count Leopold Berchtold, Austrian-Hungarian politician and diplomat, Joint Foreign Minister of Austria-Hungary (d. 1942)
 * 1863  – Linton Hope, English sailor and architect (d. 1920)
 * 1863  – Siegfried Bettmann, founder of the Triumph Motorcycle Company and Mayor of Coventry (d. 1955)
 * 1864 – Richard Harding Davis, American journalist and author (d. 1916)
 * 1874 – Ivana Brlić-Mažuranić, Croatian author and poet (d. 1938)
 * 1877 – Vicente Sotto, Filipino lawyer and politician (d. 1950)
 * 1879 – Korneli Kekelidze, Georgian philologist and scholar (d. 1962)
 * 1880 – Sam Crawford, American baseball player, coach, and umpire (d. 1968)
 * 1882 – Isaac Babalola Akinyele, Nigerian ruler (d. 1964)
 * 1882  – Leopold Stokowski, English conductor (d. 1977)
 * 1883 – Aleksanteri Aava, Finnish poet (d. 1956)
 * 1884 – Jaan Anvelt, Estonian educator and politician (d. 1937)
 * 1889 – Jessie Street, Australian activist (d. 1970)
 * 1892 – Eugene Houdry, French-American mechanical engineer and inventor (d. 1962)
 * 1897 – Ardito Desio, Italian geologist and cartographer (d. 2001)
 * 1898 – Patrick Hennessy, Irish soldier and businessman (d. 1981)
 * 1900 – Bertha Isaacs, Bahamian teacher, tennis player, politician and women's rights activist (d. 1997)

1901–present

 * 1901 – Al Lewis, American songwriter (d. 1967)
 * 1901  – László Németh, Hungarian dentist, author, and playwright (d. 1975)
 * 1902 – Waldemar Hammenhög, Swedish author (d. 1972)
 * 1902  – Giuseppe Pella, Italian politician, 32nd Prime Minister of Italy (d. 1981)
 * 1904 – Pigmeat Markham, African-American comedian, singer, and dancer (d. 1981)
 * 1905 – Sydney Halter, Canadian lawyer and businessman (d. 1990)
 * 1905  – George H. Hitchings, American physician and pharmacologist, Nobel Prize laureate (d. 1998)
 * 1907 – Miklós Rózsa, Hungarian-American composer and conductor (d. 1995)
 * 1911 – Maurice Goldhaber, Ukrainian-American physicist and academic (d. 2011)
 * 1914 – Claire Martin, Canadian author (d. 2014)
 * 1915 – Joy Davidman, Polish-Ukrainian American poet and author (d. 1960)
 * 1916 – Carl Burgos, American illustrator (d. 1984)
 * 1918 – Gabriel Axel, Danish-French actor, director, and producer (d. 2014)
 * 1918  – André Bazin, French critic and theorist (d. 1958)
 * 1918  – Shinobu Hashimoto, Japanese director, producer, and screenwriter (d. 2018)
 * 1918  – Clifton Hillegass, American publisher, founded CliffsNotes (d. 2001)
 * 1918  – Tony Mottola, American guitarist and composer (d. 2004)
 * 1919 – Virginia O'Brien, American actress and singer (d. 2001)
 * 1919  – Esther Afua Ocloo, Ghanaian entrepreneur and pioneer of microlending (d. 2002)
 * 1920 – John F. Wiley, American football player and coach (d. 2013)
 * 1921 – Jean Richard, French actor and singer (d. 2001)
 * 1922 – Barbara Hale, American actress (d. 2017)
 * 1924 – Clarence "Gatemouth" Brown, American singer-songwriter and guitarist (d. 2005)
 * 1925 – Marcus Schmuck, Austrian mountaineer and author (d. 2005)
 * 1926 – Doug Insole, English cricketer (d. 2017)
 * 1927 – Samuel P. Huntington, American political scientist, author, and academic (d. 2008)
 * 1927  – Tadeusz Mazowiecki, Polish journalist and politician, Prime Minister of Poland (d. 2013)
 * 1928 – Karl Josef Becker, German cardinal and theologian (d. 2015)
 * 1928  – Otto Piene, German sculptor and academic (d. 2014)
 * 1929 – Peter Hordern, English soldier and politician (d. 2024)
 * 1930 – Clive Revill, New Zealand actor and singer
 * 1931 – Bill Miles, American director and producer (d. 2013)
 * 1934 – James Drury, American actor (d. 2020)
 * 1934  – George Shirley, African-American tenor and educator
 * 1935 – Costas Ferris, Egyptian-Greek actor, director, producer, and screenwriter
 * 1936 – Roger Graef, American-English criminologist, director, and producer (d. 2022)
 * 1936  – Vladimir Hütt, Estonian physicist and philosopher (d. 1997)
 * 1937 – Keiko Abe, Japanese marimba player and composer
 * 1937  – Jan Kaplický, Czech architect, designed the Selfridges Building (d. 2009)
 * 1939 – Glen Hardin, American pianist and arranger
 * 1939  – Thomas J. Moyer, American lawyer and judge (d. 2010)
 * 1940 – Joseph L. Goldstein, American biochemist and geneticist, Nobel Prize laureate
 * 1940  – Mike Vickers, English guitarist, saxophonist, and songwriter
 * 1941 – Michael D. Higgins, Irish sociologist and politician, 9th President of Ireland
 * 1942 – Michael Beloff, English lawyer and academic
 * 1942  – Robert Christgau, American journalist and critic
 * 1942  – Jochen Rindt, German-Austrian racing driver (d. 1970)
 * 1944 – Kathy Acker, American author and poet (d. 1997)
 * 1944  – Philip Jackson, Scottish sculptor and photographer
 * 1945 – Bernard Arcand, Canadian anthropologist and author (d. 2009)
 * 1946 – Hayley Mills, English actress
 * 1947 – Moses Blah, Liberian general and politician, 23rd President of Liberia (d. 2013)
 * 1947  – Jerzy Stuhr, Polish actor, director, and screenwriter
 * 1947  – James Woods, American actor and producer
 * 1948 – Régis Wargnier, French director, producer, and screenwriter
 * 1950 – Grigory Sokolov, Russian pianist and composer
 * 1953 – Rick Moranis, Canadian-American actor, comedian, singer and screenwriter
 * 1954 – Robert Greenberg, American pianist and composer
 * 1956 – Eric Roberts, American actor
 * 1958 – Gabi Delgado-López, Spanish-German singer, co-founder of D.A.F. (d. 2020)
 * 1958  – Malcolm Marshall, Barbadian cricketer and coach (d. 1999)
 * 1959 – Susan Faludi, American journalist, author and feminist
 * 1960  – Yelena Zhupiyeva-Vyazova, Ukrainian runner
 * 1961 – Jane Leeves, English actress and dancer
 * 1961  – John Podhoretz, American journalist and author
 * 1962 – Jeff Dunham, American ventriloquist and comedian
 * 1963 – Eric McCormack, Canadian-American actor
 * 1963  – Conan O'Brien, American television host, comedian, and podcaster
 * 1964 – Niall Ferguson, Scottish historian and academic
 * 1967 – Maria Bello, American actress
 * 1969 – Keith DeCandido, American author
 * 1970 – Saad Hariri, Saudi Arabian-Lebanese businessman and politician, 33rd Prime Minister of Lebanon
 * 1970  – Willie Roaf, American football player
 * 1971 – David Tennant, Scottish actor
 * 1972 – Rosa Clemente, American journalist and activist
 * 1972  – Eli Roth, American actor, director, producer, and screenwriter
 * 1973 – Derrick Brooks, American football player
 * 1973  – Haile Gebrselassie, Ethiopian runner
 * 1974 – Edgar Wright, English filmmaker
 * 1976 – Melissa Joan Hart, American actress
 * 1979 – Kourtney Kardashian, American television personality
 * 1981 – Audrey Tang, Taiwanese computer scientist and academic
 * 1983 – Miguel Cabrera, Venezuelan baseball player
 * 1984 – America Ferrera, American actress
 * 1985 – Łukasz Fabiański, Polish footballer
 * 1986 – Tina Bru, Norwegian politician
 * 1988 – Vanessa Kirby, English actress
 * 1989 – Jessica Jung, South Korean-American singer, songwriter, actress, author, fashion designer and businesswoman
 * 1989  – Alia Shawkat, American actress
 * 1990 – Wojciech Szczęsny, Polish footballer
 * 1992 – Chloe Bennet, American actress
 * 1993 – Mika Zibanejad, Swedish ice hockey player
 * 1994 – Aminé, American singer-songwriter
 * 1995 – Divock Origi, Belgian footballer
 * 1996 – Ski Mask the Slump God, American rapper
 * 2001 – PinkPantheress, English singer, songwriter, and record producer

Pre-1600

 * 727 – Agallianos Kontoskeles, Byzantine commander and rebel leader
 * 850 – Perfectus, Spanish monk and martyr
 * 909 – Dionysius II, Syriac Orthodox patriarch of Antioch
 * 943 – Fujiwara no Atsutada, Japanese nobleman and poet (b. 906)
 * 963 – Stephen Lekapenos, co-emperor of the Byzantine Empire
 * 1161 – Theobald of Bec, French-English archbishop (b. 1090)
 * 1176 – Galdino della Sala, Italian archdeacon and saint
 * 1430 – John III, Count of Nassau-Siegen, German count
 * 1552 – John Leland, English poet and historian (b. 1502)
 * 1555 – Polydore Vergil, English historian (b. 1470)
 * 1556 – Luigi Alamanni, Italian poet and politician (b. 1495)
 * 1567 – Wilhelm von Grumbach, German adventurer (b. 1503)
 * 1587 – John Foxe, English historian and author (b. 1516)

1601–1900

 * 1636 – Julius Caesar, English judge and politician (b. 1557)
 * 1650 – Simonds d'Ewes, English lawyer and politician (b. 1602)
 * 1674 – John Graunt, English demographer and statistician (b. 1620)
 * 1689 – George Jeffreys, 1st Baron Jeffreys, Welsh judge and politician, Lord Chancellor of Great Britain (b. 1648)
 * 1732 – Louis Feuillée, French astronomer, geographer, and botanist (b. 1660)
 * 1742 – Arvid Horn, Swedish general and politician (b. 1664)
 * 1763 – Marie-Josephte Corriveau, Canadian murderer (b. 1733)
 * 1794 – Charles Pratt, 1st Earl Camden, English lawyer, judge, and politician, Lord Chancellor of Great Britain (b. 1714)
 * 1796 – Johan Wilcke, Swedish physicist and academic (b. 1732)
 * 1802 – Erasmus Darwin, English physician and botanist (b. 1731)
 * 1832 – Jeanne-Elisabeth Chaudet, French painter (b. 1761)
 * 1859 – Tatya Tope, Indian general (b. 1814)
 * 1864 – Juris Alunāns, Latvian philologist and linguist (b. 1832)
 * 1873 – Justus von Liebig, German chemist and academic (b. 1803)
 * 1890 – Paweł Bryliński, Polish sculptor (b. 1814)
 * 1898 – Gustave Moreau, French painter and academic (b. 1826)

1901–present

 * 1906 – Luis Martín, Spanish religious leader, 24th Superior-General of the Society of Jesus (b. 1846)
 * 1912 – Martha Ripley, American physician (b. 1843)
 * 1917 – Vladimir Serbsky, Russian psychiatrist and academic (b. 1858)
 * 1923 – Savina Petrilli, Italian religious leader (b. 1851)
 * 1936 – Milton Brown, American singer and bandleader (b. 1903)
 * 1936  – Ottorino Respighi, Italian composer and conductor (b. 1879)
 * 1938 – George Bryant, American archer (b. 1878)
 * 1942 – Aleksander Mitt, Estonian speed skater (b. 1903)
 * 1942  – Gertrude Vanderbilt Whitney, American heiress, sculptor and art collector, founded the Whitney Museum of American Art (b. 1875)
 * 1943 – Isoroku Yamamoto, Japanese admiral (b. 1884)
 * 1945 – John Ambrose Fleming, English physicist and engineer, invented the vacuum tube (b. 1849)
 * 1945  – Ernie Pyle, American journalist and soldier (b. 1900)
 * 1947 – Jozef Tiso, Slovak priest and politician, President of Slovakia (b. 1887)
 * 1951 – Óscar Carmona, Portuguese field marshal and politician, 11th President of Portugal (b. 1869)
 * 1955 – Albert Einstein, German-American physicist, engineer, and academic (b. 1879)
 * 1958 – Maurice Gamelin, Belgian-French general (b. 1872)
 * 1963 – Meyer Jacobstein, American academic and politician (b. 1880)
 * 1964 – Ben Hecht, American director, producer, and screenwriter (b. 1894)
 * 1965 – Guillermo González Camarena, Mexican engineer (b. 1917)
 * 1974 – Marcel Pagnol, French author, playwright, and director (b. 1895)
 * 1988 – Oktay Rıfat Horozcu, Turkish poet and playwright (b. 1914)
 * 1995 – Arturo Frondizi, Argentinian lawyer and politician, 32nd President of Argentina (b. 1908)
 * 2002 – Thor Heyerdahl, Norwegian ethnographer and explorer (b. 1914)
 * 2004 – Kamisese Mara, Fijian politician, 2nd President of Fiji (b. 1920)
 * 2008 – Germaine Tillion, French ethnologist and anthropologist (b. 1907)
 * 2012 – Dick Clark, American television host and producer, founded Dick Clark Productions (b. 1929)
 * 2012  – René Lépine, Canadian businessman and philanthropist (b. 1929)
 * 2012  – Robert O. Ragland, American musician (b. 1931)
 * 2012  – K. D. Wentworth, American author (b. 1951)
 * 2013 – Goran Švob, Croatian philosopher and author (b. 1947)
 * 2013  – Anne Williams, English activist (b. 1951)
 * 2014 – Guru Dhanapal, Indian director and producer (b. 1959)
 * 2014  – Sanford Jay Frank, American screenwriter and producer (b. 1954)
 * 2014  – Brian Priestman, English conductor and academic (b. 1927)
 * 2019 – Lyra McKee, Irish journalist (b. 1990)
 * 2022 – Harrison Birtwistle, British composer (b. 1934)
 * 2024 – Crandell Addington, American Hall of Fame poker player. (death announced on this date) (b. 1938)
 * 2024 – Dickey Betts, American guitarist, singer, songwriter and composer (b. 1943)
 * 2024 – Mandisa, American gospel singer (b. 1976)

Holidays and observances

 * Christian feast day:
 * Apollonius the Apologist
 * Corebus
 * Cyril VI of Constantinople (Eastern Orthodox Church)
 * Eleutherius and Antia
 * Galdino della Sala
 * Molaise of Leighlin
 * Perfectus
 * April 18 (Eastern Orthodox liturgics)
 * Army Day (Iran)
 * Coma Patients' Day (Poland)
 * Friend's Day (Brazil)
 * Independence Day (Zimbabwe)
 * International Day For Monuments and Sites
 * Invention Day (Japan)
 * Victory over the Teutonic Knights in the Battle of the Ice (Russia; Julian Calendar)
 * World Amateur Radio Day

title: April 18