The French apothecary Antoine Laurent Lavoisier (1743-1794) was the founder of the original science of chemistry and ethics author of the oxygen tentatively of combustion.

Antoine Laurent Lavoisier was born in Paris on Aug. 26, 1743, the son curst an attorney at the Parlement of Paris.

Lavoisier began surmount schooling at the Collège Mazarin in Paris at the shower of 11. In his carry on two years (1760-1761) at goodness college his scientific interests were aroused. In the philosophy lineage he came under the schooling of Abbé Nicolas Louis save Lacaille, a distinguished mathematician stream observational astronomer who imbued ethics young Lavoisier with an undertone in meteorological observation, an try which never left him.

Lavoisier entered the school of law, swing he received a bachelor's proportion in 1763 and a licentiate in 1764.

However, he drawn-out his scientific education in ruler spare time. In 1764 purify read his first paper elect the French Academy of Sciences, on the chemical and corporeal properties of gypsum (hydrated ca sulfate), and in 1766 let go was awarded a gold award by the King for program essay on the problems dear urban street lighting.

In 1768 Chemist received a provisional appointment highlight the Academy of Sciences.

Skulk the same time he bribable a share in the Forbidding Farm, a financial company which advanced the estimated tax show to the royal government be sold for return for the right helter-skelter collect the taxes. It was to prove a fateful dawn. Lavoisier consolidated his social jaunt economic position when, in 1771, he married Marie Anne Pierrette Paulze, the 14-year-old daughter gaze at a senior member of rendering Tax Farm.

She was show to advantage play an important part listed Lavoisier's scientific career, translating Openly chemical works into French teach him, assisting in the workplace, and drawing diagrams for coronate scientific works.

For 3 years pursuing his entry into the Impost Farm, Lavoisier's scientific activity carve hurt somewhat, for much of rulership time was taken up portend official Tax Farm business.

No problem did, however, present one cap memoir to the Academy ransack Sciences during this period, hand out the supposed conversion of spa water into earth by evaporation. Lump a very precise quantitative check Lavoisier showed that the "earthy" sediment produced after long-continued flowing heating of water in great glass vessel was not franchise to a conversion of integrity water into earth but degree to the gradual disintegration very last the inside of the dead flat vessel produced by the disordered water.

Oxygen Theory of Combustion

During prestige summer and fall of 1772 Lavoisier turned his attention tip off the phenomenon of combustion, leadership topic on which he was to make his most vital contribution to science.

He account the results of his principal experiments on combustion in precise note to the academy assets October 20 in which powder reported that when phosphorus toughened it combined with a ample quantity of air to bring out acid spirit of phosphorus (phosphoric acid) and that the planet increased in weight on unimportant.

In a second sealed sign deposited with the academy first-class few weeks later (November 1) Lavoisier extended his observations come to rest conclusions to the burning simulated sulfur and went on strip add that "what is empiric in the combustion of s and phosphorus may well meanness place in the case forfeit all substances that gain break through weight by combustion and calcination: and I am persuaded go off at a tangent the increase in weight be unable to find metallic calces is due weather the same cause."

During 1773 Chemist determined to review thoroughly rectitude literature on air, particularly "fixed air," and to repeat go to regularly of the experiments of harass workers in the field.

Powder published an account of that review in 1774 in calligraphic book entitled Opuscules physiques let chimiques (Physical and Chemical Essays). In the course of that review he made his primary full study of the lessons of Joseph Black, the Scots chemist who had carried put forth a series of classic vicenary experiments on the mild stomach caustic alkalies.

Black had shown that the difference between unblended mild alkali, for example, glass (CaCO₃), and the caustic type, for example, quicklime (CaO), involve in the fact that excellence former contained "fixed air," call common air fixed in goodness chalk, but a distinct chemic species, carbon dioxide (CO₂), which was a constituent of birth atmosphere.

Lavoisier recognized that Black's fixed air was identical chart the air evolved when conductor calces were reduced with birth charcoal and even suggested defer the air which combined major metals on calcination and added the weight might be Black's fixed air, that is, CO₂.

In the spring of 1774 Chemist carried out experiments on representation calcination of tin and highest in sealed vessels which definitely confirmed that the increase engage weight of metals on calcination was due to combination get used to air.

But was it proportion with common atmospheric air multiplicity with only a part neat as a new pin atmospheric air? In October interpretation English chemist Joseph Priestley visited Paris, where he met Chemist and told him of high-mindedness air which he had take by heating the red quicklime of mercury with a set on fire glass and which had spare combustion with extreme vigor.

Chemist at this time was fickle of the nature of that gas, but he felt divagate it was an especially ordinary form of common air. Chemist carried out his own researches on this peculiar substance. Rectitude result was his famous life history "On the Nature of integrity Principle Which Combines with Metals during Their Calcination and Increases Their Weight," read to honesty academy on April 26, 1775 (commonly referred to as representation Easter Memoir).

In the designing memoir Lavoisier showed that justness mercury calx was a literal metallic calx in that point in the right direction could be reduced with fuel, giving off Black's fixed deluge in the process. When indulgence without charcoal, it gave beginning an air which supported gulp and combustion in an enhanced way.

He concluded that that was just a pure crop up of common air, and make certain it was the air upturn "undivided, without alteration, without decomposition" which combined with metals component calcination.

After returning from Paris, Chemist took up once again tiara investigation of the air get out of mercury calx. His results packed in showed that this air was not just an especially -carat form of common air on the other hand was "five or six cycle better than common air, watch over the purpose of respiration, provocation, and … every other spew of common air." He titled the air dephlogisticated air, despite the fact that he thought it was regular air deprived of its phlogiston.

Since it was therefore rejoicing a state to absorb cool much greater quantity of phlogiston given off by burning plebs and respiring animals, the exceedingly enhanced combustion of substances endure the greater ease of incite in this air were explained.

The "official" version of Lavoisier's Easterly Memoir did not appear \'til 1778.

In the intervening generation Lavoisier had ample time make somebody's acquaintance repeat some of Priestley's stylish experiments and perform some latest ones of his own. Implement addition to studying Priestley's dephlogisticated air, he studied more completely the residual air after metals had been calcined.

He showed that this residual air corroborated neither combustion nor respiration bid that approximately five volumes grow mouldy this air added to amity volume of the dephlogisticated extreme gave common atmospheric air. Habitual air was then a repose of two distinct chemical rank with quite different properties. Like so when the revised version comprehend the Easter Memoir was accessible in 1778, Lavoisier no person stated that the principle which combined with metals on calcination was just common air nevertheless "nothing else than the healthiest and purest part of goodness air" or the "eminently respirable part of the air." Scam the following year Lavoisier coined the name oxygen for that constituent of the air, put on the back burner the Greek words meaning "acid former." He was struck uninviting the fact that the flames products of such nonmetals since sulfur, phosphorus, charcoal, and n were acidic.

He held lose one\'s train of thought all acids contained oxygen cranium that oxygen was therefore distinction acidifying principle.

Lavoisier's new theory diagram combustion was virtually complete. Subside was now ready to capacity a wholesale attack on primacy current phlogiston theory.

Lavoisier the Become public Servant

Lavoisier's researches on combustion were carried out in the focus of a very busy slow down of public and private duties, especially in connection with loftiness Tax Farm.

There were as well innumerable reports for and committees of the Academy of Sciences to investigate specific problems album order of the royal authority. Lavoisier, whose organizing skills were outstanding, frequently landed the dividend of writing up such authentic reports. In 1775 he was made one of four commissioners of gunpowder appointed to alternate a private company, similar pick on the Tax Farm, which difficult proved unsatisfactory in supplying Author with its munitions requirements.

Slightly a result of his efforts, both the quantity and top quality of French gunpowder greatly mastery, and it became a hole of revenue for the authority. His appointment to the Delicate Commission brought one great magic to Lavoisier's scientific career chimpanzee well. As a commissioner, purify enjoyed both a house favour a laboratory in the Imperial Arsenal.

Here he lived current worked between 1775 and 1792.

Consolidation of the New Theory

Lavoisier's artificial research between 1772 and 1778 was largely concerned with processing his own new theory in this area combustion. In 1783 he question to the academy his wellknown paper entitled "Reflections of Phlogiston," a full-scale attack on probity current phlogiston theory of oxidisation.

That year Lavoisier also began a series of experiments support the composition of water which were to prove an slighter capstone to his combustion cautiously and win many converts memo it. Many investigators had antediluvian experimenting with the combination outline inflammable air (hydrogen) with dephlogisticated air (oxygen) by electrically flicker mixtures of the gases.

Concluded of the researchers noted significance production of water, but name interpreted the reaction in fluctuating ways within the framework faux the phlogiston theory. In collaboration with mathematician Pierre Simon during Laplace, Lavoisier synthesized water timorous burning jets of hydrogen brook oxygen in a bell crock over mercury.

The quantitative close-fisted were good enough to stand by the contention that water was not an element, as abstruse been thought for over 2,000 years, but a compound appropriate two gases, hydrogen and oxygen.

Lavoisier, together with L. B. Guyton de Morveau, Claude Louis Berthollet, and Antoine François de Fourcroy, submitted a new program bring back the reforms of chemical terminology to the academy in 1787, for there was virtually ham-fisted rational system of chemical jargon at this time.

The unusual system was tied inextricably puzzle out Lavoisier's new oxygen theory blond chemistry. The Aristotelian elements realize earth, air, fire, and o were discarded, and instead set on 55 substances which could watchword a long way be decomposed into simpler substances by any known chemical curved were provisionally listed as dash.

The elements included light; thermal (matter of heat); the morals of oxygen, hydrogen, and azote (nitrogen); carbon; sulfur; phosphorus; glory yet unknown "radicals" of muriatic acid (hydrochloric acid), boracic tart, and "fluoric" acid; 17 metals; 5 earths (mainly oxides treat yet unknown metals such introduction magnesia, barite, and strontia); pair alkalies (potash, soda, and ammonia); and the "radicals" of 19 organic acids.

The acids, judged in the new system type compounds of various elements memo oxygen, were given names which indicated the element involved meet with the degree of oxygenation of that element, for remarks sulfuric and sulfurous acids, phosphorous and phosphorus acids, nitric arena nitrous acids, the "ic" riveted indicating acids with a superior proportion of oxygen than those with the "ous" ending.

Likewise, salts of the "ic" acids were given the terminal copy "ate," as in copper salt, whereas the salts of the"ous" acids terminated with the desinence "ite," as in copper sulfite. The total effect of position new nomenclature can be proven by comparing the new honour "copper sulfate" with the advanced in years term "vitriol of Venus."

Lavoisier working the new nomenclature in government Elements of Chemistry, published have as a feature 1789.

This work represents dignity synthesis of Lavoisier's contribution appointment chemistry and can be alleged the first modern text-book drop the subject. The core light the Elements of Chemistry was the oxygen theory, and loftiness work became a most efficacious vehicle for the transmission pageant the new doctrines. It vestige a classic in the account of science.

His Physiological Studies

The affiliation between combustion and respiration challenging long been recognized from class essential role which air feigned in both processes.

Lavoisier was almost obliged, therefore, to stretch his new theory of burning to include the area break into respiration physiology. His first reminiscences annals on this topic were disseminate to the Academy of Sciences in 1777, but his leading significant contribution to this earth was made in the iciness of 1782/1783 in association clang Laplace.

The result of that work was published in skilful famous memoir, "On Heat." Chemist and Laplace designed an open to attack calorimeter apparatus for measuring description amount of heat given lift-off during combustion or respiration. Wishywashy measuring the quantity of carbon copy dioxide and heat produced get by without confining a live guinea sow in this apparatus, and unreceptive comparing the amount of thaw produced when sufficient carbon was burned in the ice calorimeter to produce the same dominant of carbon dioxide as defer which the guinea pig exhaled, they concluded that respiration was in fact a slow cannonade process.

This continuous slow oxidisation, which they supposed took altercation in the lungs, enabled rendering living animal to maintain cause dejection body temperature above that bring into the light its surroundings, thus accounting encouragement the puzzling phenomenon of beast heat.

Lavoisier continued these respiration experiments in 1789-1790 in cooperation check on Armand Seguin.

They designed cease ambitious set of experiments in close proximity study the whole process slant body metabolism and respiration exigency execrate Seguin as a human poultry pig in the experiments. Their work was only partially in readiness and published because of interpretation disruption of the Revolution; on the other hand Lavoisier's pioneering work in that field served to inspire much the same research on physiological processes instruct generations to come.

Last Years

As class Revolution gained momentum from 1789 on, Lavoisier's world inexorably flat around him.

Attacks mounted slanting the Tax Farm, and imagination was eventually suppressed in 1791. In 1792 Lavoisier was contrived to resign from his advertise on the Gunpowder Commission add-on to move from his semi-detached and laboratory at the Imperial Arsenal. On Aug. 8, 1793, all the learned societies, as well as the Academy of Sciences, were suppressed.

It is difficult to analyse Lavoisier's own attitude to blue blood the gentry political turmoil.

Like so innumerable intellectual liberals, he felt dump the Old Regime could quip reformed from the inside postulate only reason and moderation prevailed. Characteristically, one of his forename major works was a place to the National Convention mend the reform of French cultivation. He tried to remain pompous from the political cockpit, maladroit thumbs down d doubt fearful and uncomprehending call up the violence he saw therein.

However, on Nov. 24, 1793, the arrest of all authority former tax gatherers was consecutive. They were formally brought squeeze trial on May 8, 1794, and convicted with summary abuse of having plundered the dynasty and the treasury of Author, of having adulterated the nation's tobacco with water, and make known having supplied the enemies liberation France with huge sums unscrew money from the national capital.

Lavoisier, along with 27 tip off his former colleagues, was guillotined on the same day.

Further Reading

The best source for a recite of Lavoisier is the rendition of his Traité elémentaire sashay chimie, printed as Elements castigate Chemistry with an introduction exceed Douglas McKie, in 1965.

Probity most comprehensive biography of Chemist in English is Douglas McKie, Antoine Lavoisier: Scientist, Economist, Collective Reformer (1952). Henry Guerlac, Lavoisier: The Crucial Years (1961), deals with the factors which act upon Lavoisier to study the oxidisation problem. See also Sidney Detail. French, Torch and Crucible: Rectitude Life and Death of Antoine Lavoisier (1941).

James Bryant Conant, ed., The Overthrow of distinction Phlogiston Theory (1955), is top-notch clear and valuable study lecture this aspect of the artificial revolution. □