During the last century, historians have discovered that between the 13th and 18th centuries, at least six sages discovered that the air we breathe contains something that we need and use. Ibn al-Nafis (1213–1288) in Cairo and Michael Servetus (1511–1553) in France accurately described the pulmonary circulation and its effect on blood color. Michael Sendivogius (1566–1636) in Poland called a part of air “the food of life” and identified it as the gas made by heating saltpetre. John Mayow (1641–1679) in Oxford found that one-fifth of air was a special gas he called “spiritus nitro aereus.” Carl Wilhelm Scheele (1742–1786) in Uppsala generated a gas he named “fire air” by heating several metal calcs. He asked Lavoisier how it fit the phlogiston theory. Lavoisier never answered. In 1744, Joseph Priestley (1733–1804) in England discovered how to make part of air by heating red calc of mercury. He found it brightened a flame and supported life in a mouse in a sealed bottle. He called it “dephlogisticated air.” He published and personally told Lavoisier and other chemists about it. Lavoisier never thanked him. After 9 years of generating and studying its chemistry, he couldn't understand whether it was a new element. He still named it “principe oxigene.” He was still not able to disprove phlogiston. Henry Cavendish (1731–1810) made an inflammable gas in 1766. He and Priestley noted that its flame made a dew. Cavendish proved the dew was pure water and published this in 1778, but all scientists called it impossible to make water, an element. In 1783, on June 24th, Lavoisier was urged to try it, and, when water appeared, he realized that water was not an element but a compound of two gases, proving that oxygen was an element. He then demolished phlogiston and began the new chemistry revolution.
lavoisier, the greatest chemist of the 18th century, both plagiarized and stumbled until he was urged to do a simple experiment.
Ibn al-Nafis (1213–1288)
The story of oxygen begins in the 13th century with Ibn al-Nafis (Fig. 1), a Syrian physician and anatomist who became the Egyptian sultan's doctor and chief of Cairo's hospital. In 1250 CE, he correctly described the pulmonary circulation and oxygen in a single sentence: “Pulmonary arterial blood passes through invisible pores in the lung, where it mingles with air to form the vital spirit and then passes through the pulmonary vein to reach the left chamber of the heart.” Vital spirit was a term used by Galen in ∼200 CE to refer to red (arterialized) blood.
Al-Nafis clearly was the first to understand lung blood flow, 400 years before William Harvey. This finding was scarcely known in the West until discovered in the Prussian state library in 1924 (1, 2) by Egyptian medical historian Muhyo al-Deen.
Nafis wrote over 100 medical texts, science fiction novels, and humorous theological novels.
Michael Servetus (1511–1553)
Three hundred years later, Michael Servetus (Fig. 2) rediscovered the pulmonary circulation and blood color change in the lung. He was a brilliant polymath, geographer, mapmaker, biblical scholar, and doctor who became physician to the archbishop of Vienne (Dauphiné), France. Early in Martin Luther's Reformation, Servetus got into trouble by repeatedly writing that doctrines of the trinity and infant baptism were not biblical. Both Catholics and Protestants declared him a heretic. To avoid the Inquisition, he hid in Strasburg, and, under a pseudonym, he wrote Christianity Restored (also called Restoration of Christianity) in 1553, proposing that the Reformation should return to biblical roots. He sent John Calvin a copy. Calvin realized his authorship.
Figure 3 shows the cover page of Christianity Restored. Calvin threatened to have him killed for heresy if he came to Geneva. Inquisition leaders burned him in effigy.
While escaping to Italy, rashly and inexplicably, he snuck into Calvin's church in Geneva. He was recognized, reported, arrested, and jailed as a heretic by order of Geneva's government. He was held for over 2 month in prison while Calvin consulted with all the Swiss cantons and was then indicted.
On Oct. 27, 1553, Servetus was burned at the stake in the Champel district of Geneva, with a copy of Christianity Restored strapped to his leg.
Calvin ordered the burning of all copies of his book. It contained Servetus's only description of the effects of air on blood in the lung. His science report remained unknown for 400 years.
A French historian, August Dide, published a book called “Heretics and Revolutionaries” in 1887. After his election as a Senator in 1900, Dide proposed erecting a monument in Geneva to Michael Servetus as France's most important heretical martyr. In 1907, Rodin's pupil, Clothilde Roch, finished a sculpture of Servetus in prison. The Calvinist Geneva town council refused to celebrate a heretic. So Dide had it mounted nearby in France, angering the Calvinists. During World War II, the Vichy government melted it because Servetus championed freedom of speech. In 2011, on Servetus's 500th birthday, Roch's sculpture was recast and mounted in Geneva near the site of his burning with the agreement of Geneva's now secular government (Fig. 4).
In 1953, 400 years after Servetus' martyrdom, Roland Bainton, Yale Professor of Ecclesiastical History, by borrowing one of the three surviving copies of Servetus' heretical book, published the most authoritative Servetus biography, Hunted Heretic (3). Bainton had spent most of 20 years studying Servetus' life and works. Bainton's colleague at Yale, John Fulton, Professor of Physiology, found in it Servetus's unknown description of the pulmonary circulation (4, 5). It is now clear that Servetus had discovered, a century before William Harvey, that blood flows through lung tissue, excreting waste products into the air and changing the color of blood (5, 6).
Michael Sendivogius (1566–1636)
The third sage was a famous 16th century Polish noble physician and alchemist, Michael Sendivogius (Fig. 5). In 1604, he published that air contains what he named the “secret food of life.” He had realized that this “food” was the same gas emitted by saltpetre (potassium nitrate) when heated. He called it part of the “saltnitre of the earth.” Sendivogius's writings were frequently copied and read for over a century. However, no one grasped the chemical importance of his discovery, not even physicists Boyle and Newton at Oxford, who read his work 60 years later.
In 1621, a Dutch inventor named Drebbel built the world's first manned submarine (Fig. 6). King James I and a horde of viewers watched it travel submerged 10 miles down the Thames from Westminster to Greenwich. Drebbel never revealed the secret of refreshing submarine air, but newspapers and others believed that he had learned from Sendivogius in Prague how to make oxygen on board. I doubt that and suspect the rowers sucked in air through tubes to snorkles from little surface floats some said they saw.
Forty years later, Robert Boyle in Oxford wrote that he had spoken with a mathematician who had been on Drebbel's submarine. He said that “Drebbel used a chemical liquor to replace the quintessence of air.” Although both Boyle and Newton read Sendivogius, they ignored his work, perhaps because they didn't grasp the importance of his chemistry. Or, perhaps they thought he was just another fraudulent alchemist.
Sendivogius' “food of life” story was only recently rediscovered. A biography of Sendivogius was published in Polish in Warsaw by Roman Bugnai in 1968 (6) as a study of his alchemical pursuits. Water Which Does Not Wet Hands: the alchemy of Michael Sendivogius was published in English in 1994 by Andrew Szydlo (7). Szydlo was born of Polish parents in England and educated in London's universities. He teaches chemistry at London's Highgate School. He is a dramatic lecturer with demonstrations to fascinated audiences.
John Mayow (1641–1679)
In Oxford, in 1668, Robert Boyle's former student, John Mayow (Fig. 7), wrote a book about a part of air he named “spiritus nitro-aereus.” He wrote that it is consumed in fire and that we breathe it to provide both body heat and energy. He was the fourth discoverer of oxygen. He was unaware of Sendivogius.
Mayow's own work sank into obscurity when all scientists accepted the false phlogiston theory postulated by a famous German physician, Georg Ernst Stahl, in the early 17th century. This mythical substance postulated that a fire-like element called phlogiston is contained within combustible bodies and released during combustion, avoiding the need for air in fire or life. This idea obstructed reality-based science for nearly a century.
In 1955, Mayow's book about oxygen was rediscovered and published by Donald Proctor at Johns Hopkins University School of Medicine (9).
Carl Wilhelm Scheele (1742–1786)
The fifth discoverer of oxygen, Carl Wilhelm Scheele (Fig. 8), was born in German-speaking Pomerania. Trained in Sweden, he became a very clever apothecary and chemist. In 1768, he published new studies of metal chemistry. In 1770, he became director of Locke Pharmacy in Uppsala. He worked at the university there with the famous chemist Torbern Bergman, who helped him publish his work in Latin in the journal Nova Acta.
In 1774, Lavoisier sent his new chemistry textbook to Bergman, including a copy for Scheele, whose published work he much admired.
Scheele promptly wrote Lavoisier to thank him for the book. He explained how, in 1771, he had generated a strange new gas by heating certain metallic earths. He had named it fire air because it greatly brightened a candle flame and supported life in mice. Because neither he nor Bergman could relate it to the phlogiston theory, Scheele had delayed publishing. He asked Lavoisier to repeat the experiment and then help him explain it.
By the time Scheele finally decided in 1775 to publish his fire air with all his experimental findings, he had read about Joseph Priestley's 1774 discovery of the same gas, so it was too late to claim its discovery. Scheele wrote that Lavoisier never answered his letter (10). His book was finally published in 1777, but he could not confirm his claim of discovering fire air. Scientists and historians therefore ignored his oxygen discovery.
Working in Uppsala and later in Köping, Sweden, as an apothecary, Scheele became one of the world's greatest experimental chemists. He discovered seven elements and much other new chemistry. On February 4, 1775, he was elected to membership in the Royal Swedish Academy of Sciences, although his discovery of oxygen was unpublished and unknown. This great honor, with the King of Sweden attending, had never before or since been given to an apothecary. Over his last 15 years, he published 48 chemistry discovery papers.
In 1893, French historian Édouard Grimaux was shown Scheele's letter to Lavoisier, never previously seen. He published the text but could not show it because it had been withdrawn by its private owners.
A century later, in 1993, various Lavoisier artifacts were donated to the French Academy of Science to avoid high taxation. Among them was Scheele's 1774 letter to Lavoisier. Descendants of Lavoisier's wife's brother had hidden the letter for 219 years because they were aware that it proved that the great chemist used Scheele's methods without acknowledgement, proving him guilty of plagiarism.
Joseph Priestley (1733–1804)
Oxygen's sixth discoverer was Unitarian minister Joseph Priestley (Fig. 9). Two churches fired him as too radical, but he soon became famous while teaching grammar and science at Warrington Academy near Manchester, helping to make it a leading school for dissenters–in fact, the “cradle of Unitarianism,” as one scholar called it.
In the 1760s, Benjamin Franklin, while living in England, befriended Priestley and provided books on electricity as well as experimental apparati. In 1766, Franklin persuaded the Royal Society to elect Priestley to membership at the age of 33 years. The next year, Priestley published the most authoritative and popular text on electricity. He was awarded the Royal Society's Copley medal in 1773, partly for discovering how to make cheap soda water from brewery exhaust. Encouraged by Franklin, the Earl of Shelburne offered Priestley a laboratory on his Bowood estate in Wiltshire.
On August 1, 1774, Priestley, by heating red mercury calc, made a gas that caused a glowing splinter to burst into flame and supported life in a mouse in a bottle. He named it dephlogisticated air (12). In October 1774 in Paris, he described his method of making it to Lavoisier, who never acknowledged his help.
Antoine Laurent Lavoisier (1743–1794)
Lavoisier (Fig. 10) had become the world's most brilliant chemist by the age of 30 years. In the spring of 1775, he began his studies of Priestley's newly published gas. He named it principe oxigene but continued to refer to it as “vital air.” However, after 8 years of extensively examining its chemistry, he was still unable to prove whether vital air was a new element or a compound. And he doubted but still couldn't disprove the phlogiston theory. By 1783, he was stalled by these dilemmas (13).
Henry Cavendish (1731–1810)
In 1766, Cavendish (Fig. 11) discovered and published how to make an inflammable gas (H2) by putting iron filings in strong acid (14). In the late 1770s, he and Priestley noted that burning inflammable air caused dew to form on glass walls. Cavendish analyzed and proved the dew was pure water. His peers in the Royal Society considered his claim of making water to be wrong, since all assumed that water was an element that can't be made.
In 1783, when Cavendish's associate, physicist Charles Blagden, became president of the Royal Society, he proposed to be sent to ask Lavoisier to help understand the unbelievable Cavendish report. He persuaded Lavoisier to test the Cavendish-Priestley observation by burning inflammable air himself.
On June 24, 1783, Lavoisier invited eight chemists to watch him prove that Cavendish was wrong. When water appeared, Lavoisier was stunned! He suddenly realized that the Cavendish observation had revealed a universally accepted error. He declared:
Water is not an element, but a compound made of inflammable air and vital air.
Lavoisier then named inflammable air “hydrogen” and vital air “oxygen.”
Lavoisier's insight created the greatest Kuhnian paradigm shift (15) in the history of chemistry. It led to his great chemical revolution. Cavendish had provided the key.
Over the next 6 years, Lavoisier demolished phlogiston and revised all chemical theory. In 1788, at age of the 45 years, he finished writing his revolutionary treatise, Elements of Chemistry (16).
In celebration, his 29-year-old wife Marie Anne commissioned a portrait from France's greatest artist of the time, Jacques Louis David. He charged perhaps the highest artistic fee of all time, 7,000 livre (about a quarter million United States dollars) for this now-famous huge (2.6 m tall) double portrait of Lavoisier and his wife (Fig. 12).
What About Lavoisier?
In his Elements of Chemistry, Lavoisier falsely wrote that “This species of air was discovered almost at the same time by Mr. Priestley, Mr. Scheele, and myself,” both a bold lie and proof that he had read Scheele's 1774 letter, using his method of making fire air while failing to acknowledge Scheele!
Lavoisier was condemned in print by Edmond Genet, later French ambassador to the United States, by Joseph Black, the discoverer of CO2, and by Priestley himself, who accused him of plagiarism (17) for claims of discoveries that actually belonged to others.
Lavoisier was a brilliant polymath, meticulous scientist, and the most able chemist of his time. Born into a wealthy family, he became even richer as a despised tax “farmer” in France's ancien régime, who built a hated wall around Paris to ensure that incoming merchants would pay taxes. As a leading figure in the Academy of Science in 1780, he belittled the work of an aspiring academician, Jean Paul Marat, making a bitter enemy. More than a decade later, during the French Revolution, the now-radical revolutionary publicist Marat would repeatedly demand in newspapers that Lavoisier be guillotined as among the worst of the ancient régime. At the peak of the Reign of Terror, the Revolutionary Tribunal tried, convicted, and beheaded the great chemist all in one day, May 8, 1794 (11).
What About Henry Cavendish (Fellowship of the Royal Society)?
Cavendish was part of eight centuries of an immensely wealthy aristocratic family. He was very shy and reclusive. He never married and never sat for a portrait. He built his laboratory and lived part of his life in the home of his father, Lord Charles Cavendish, in Bloomsbury on the corner of Bedford Square beside the British Museum and University College. This plaque (Fig. 13) is on the wall there (18).
Cavendish was a natural philosopher, scientist, and great experimental and theoretical chemist and physicist. He was first to weigh the earth by a method still named the Cavendish experiment. These very famous original and new physics laboratories (Fig. 14) in Cambridge are named after him.
In conclusion, I submit that Cavendish made the most important single experimental observation of science because it solved Lavoisier's dilemma. This merits calling Cavendish the eighth discoverer of oxygen. The Encyclopedia Britannica calls him the greatest experimental and theoretical English chemist and physicist of his age. But no one of these eight sages can now be called the most important discoverer of oxygen.
No conflicts of interest, financial or otherwise, are declared by the author(s).
J.W.S. edited and revised manuscript; J.W.S. approved final version of manuscript.
Milton Djuric (history editor at Williams College) greatly assisted me with both the history and text. Martyna Elas (biochemist at Krakow University) informed me of the evidence about Sendivogius. Nobelist Cornell Prof. Roald Prof. Roald Hoffmann sent me a copy of Scheele's letter to Lavoisier. A condensed version of this article has previously been posted online at http://www.josephpriestleyhouse.org/wp-content/uploads/Eight-Sages-over-Five-Centuries-Share-Oxygen-Discovery.pdf.
- Copyright © 2016 The American Physiological Society