Swedish German chemist who discovered oxygen (1742–1786)
Carl Wilhelm Scheele
An interpretation of Scheele from the late 19th or early 20th century as no contemporary portraits of him are known (by xylographer Ida Amanda Maria Falander (1842–1927))[1]
Scheele was born in Stralsund,[2] in western Pomerania, which at the time was a Swedish Dominion inside the Holy Roman Empire. Scheele's father, Joachim (or Johann[2]) Christian Scheele, was a grain dealer and brewer[2] from a respected Pomeranian family.[citation needed] His mother was Margaretha Eleanore Warnekros.[2]
Friends of Scheele's parents taught him the art of reading prescriptions and the meaning of chemical and pharmaceutical signs.[2] Then, in 1757, at the age of fourteen, Carl was sent to Gothenburg as an apprentice pharmacist[5] to another family friend and apothecary, Martin Andreas Bauch. Scheele retained this position for eight years. During this time he ran experiments late into the night and read the works of Nicolas Lemery, Caspar Neumann, Johann von Löwenstern-Kunckel and Georg Ernst Stahl (the champion of the phlogiston theory). Much of Scheele's later theoretical speculations were based upon Stahl.[2]
In the fall of 1770 Scheele became director of the laboratory of the great pharmacy of Locke, at Uppsala, about 65 km (40 mi) north of Stockholm. The laboratory supplied chemicals to Professor of Chemistry Torbern Bergman. A friendship developed between Scheele and Bergman after Scheele analyzed a reaction which Bergman and his assistant, Johan Gottlieb Gahn, could not resolve. The reaction was between melted saltpetre and acetic acid that produced a red vapor.[2][6] Further study of this reaction later led to Scheele's discovery of oxygen (see "The theory of phlogiston" below). Based upon this friendship and respect, Scheele was given free use of Bergman's laboratory. Both men were profiting from their working relationship. In 1774 Scheele was nominated by Peter Jonas Bergius to be a member of the Royal Swedish Academy of Sciences and was elected 4 February 1775.[2] In 1775 Scheele also managed for a short time a pharmacy in Köping. Between the end of 1776 and the beginning of 1777 Scheele established his own business there.[2]
On 29 October 1777, Scheele took his seat for the first and only time at a meeting of the Academy of Sciences and on 11 November passed the examination as apothecary before the Royal Medical College, doing so with the highest honours. After his return to Köping he devoted himself, outside of his business, to scientific researches which resulted in a long series of important papers.[2]
Isaac Asimov called him "hard-luck Scheele" because he made a number of chemical discoveries that were later credited to others.[citation needed]
Existing theories before Scheele
By the time he was a teenager, Scheele had learned the dominant theory of gases which in the 1770s was the phlogiston theory. Phlogiston, classified as "matter of fire", was supposed to be released from any burning material, and when it was exhausted, combustion would stop. When Scheele discovered oxygen he called it "fire air" as it supported combustion. Scheele explained oxygen using phlogistical terms because he did not believe that his discovery disproved the phlogiston theory.
Before Scheele made his discovery of oxygen, he studied air. Air was thought to be an element that made up the environment in which chemical reactions took place but did not interfere with the reactions. Scheele's investigation of air enabled him to conclude that air was a mixture of "fire air" and "foul air"; in other words, a mixture of two gases. Scheele performed numerous experiments in which he heated substances such as saltpetre (potassium nitrate), manganese dioxide, heavy metal nitrates, silver carbonate and mercuric oxide. In all of these experiments, he isolated the same gas: his "fire air", which he believed combined with phlogiston in materials to be released during heat-releasing reactions.
However, his first publication, Chemische Abhandlung von der Luft und dem Feuer, was delivered to the printer Swederus in 1775, but not published until 1777, at which time both Joseph Priestley and Antoine Lavoisier had already published their experimental data and conclusions concerning oxygen and the phlogiston theory. Carl was credited for finding oxygen with two other people, Joseph Priestley and Antoine Lavoisier. The first English edition, Chemical Observation and Experiments on Air and Fire was published in 1780, with an introduction "Chemical Treatise on Air and Fire".[7]
The theory of phlogiston
Engraving on the title page of Scheele's Chemical Treatise on Air and Fire (1777) (d. Königl. Schwed. Acad. d. Wissenschaft Mitgliedes, Chemische Abhandlung von der Luft und dem Feuer)
Scheele achieved astonishingly prolific and important results without the expensive laboratory equipment to which his Parisian contemporary Antoine Lavoisier was accustomed. Through the studies of Lavoisier, Priestley, Scheele, and others, chemistry was made a standardized field with consistent procedures. Although Scheele was unable to grasp the significance of his discovery of the substance that Lavoisier later named oxygen, his work was essential for the abandonment of the long-held theory of phlogiston.[8]
Scheele's study of the gas not yet named oxygen was prompted by a complaint by Torbern Olof Bergman, a professor at Uppsala University who would eventually become Scheele's friend. Bergman informed Scheele that the saltpeter he had purchased from Scheele's employer, after long heating, produced red vapors (now known to be nitrogen dioxide) when it came into contact with acetic acid. Scheele's quick explanation was that the saltpeter had absorbed phlogiston with the heat (had been reduced to nitrite, in modern terms) and gave off a new phlogisticated gas as an active principle when combined with an acid (even a weak acid).
Bergman next suggested that Scheele analyze the properties of manganese(IV) oxide. It was through his studies of manganese(IV) oxide that Scheele developed his concept of "fire air" (his name for oxygen). He ultimately obtained oxygen by heating mercuric oxide, silver carbonate, magnesium nitrate, and other nitrate salts. Scheele wrote about his findings to Lavoisier who was able to see the significance of the results. His discovery of oxygen (ca. 1771) was chronologically earlier than the corresponding work of Priestley and Lavoisier, but he did not publish this discovery until 1777, after both of his rivals had published.[9]
Although Scheele would always believe in some form of the phlogiston theory, his work reduced phlogiston to an unusually simple form, complicated only by the fact that chemists of Scheele's day still believed that light and heat were elements and were to be found in combination with them. Thus, Scheele assumed that hydrogen was composed of phlogiston (a reducing principle lost when objects were burned) plus heat. Scheele speculated that his fire air or oxygen (which he found the active part of air, estimating it to compose one quarter of air) combined with the phlogiston in objects to produce either light or heat (light and heat were presumed to be composed of differing proportions of phlogiston and oxygen).
When other chemists later showed water is produced when burning hydrogen and that rusting of metals added weight to them and that passing water over hot iron gave hydrogen, Scheele modified his theory to suggest that oxygen was the salt (or "saline principle" of water), and that when added to iron, water was reproduced, which added weight to the iron as rust.
Scheele made one other very important scientific discovery in 1774, arguably more revolutionary than his isolation of oxygen. He identified lime, silica, and iron in a specimen of pyrolusite (impure manganese dioxide) given to him by his friend, Johann Gottlieb Gahn, but could not identify an additional component (this was the manganese, which Scheele recognized was present as a new element, but could not isolate). When he treated the pyrolusite with hydrochloric acid over a warm sand bath, a yellow-green gas with a strong odor was produced.[21] He found that the gas sank to the bottom of an open bottle and was denser than ordinary air. He also noted that the gas was not soluble in water. It turned corks a yellow color and removed all color from wet, blue litmus paper and some flowers. He called this gas with bleaching abilities, "dephlogisticated muriatic acid" (dephlogisticated hydrochloric acid, or oxidized hydrochloric acid). Eventually, Sir Humphry Davy named the gas chlorine, with reference to its pale green colour.
Chlorine's bleaching properties were eventually turned into an industry by Berzelius, and became the foundation of a second industry of disinfection and deodorization of putrefied tissue and wounds (including wounds in living humans) in the hands of Labarraque, by 1824.
In the fall of 1785, Scheele began to suffer from symptoms described as kidney disease.[2] In early 1786, he also contracted a disease of the skin, which, combined with his kidney problems, so enfeebled him that he could foresee an early death. With that in mind, he married the widow of his predecessor,[2] Pohl, two days before he died, so that he could pass undisputed title to his pharmacy and his possessions to her.
While Scheele's experiments generated substances which have long since been found to be hazardous, the compounds and elements he used to start his experiments were dangerous to begin with, especially heavy metals. Like most of his contemporaries, in an age where there were few methods of chemical characterisation, Scheele would smell and taste any new substances he discovered.[22] Cumulative exposure to arsenic, mercury, lead, and their compounds and, perhaps, hydrofluoric acid, which he had discovered, as well as other substances, took their toll on Scheele. He died at the early age of 43, on 21 May 1786, at his home in Köping. Doctors said that he died of mercury poisoning.[citation needed]
Published papers
Mémoires de chymie, 1785, French translation by Mme. Claudine PicardetEarly history of chlorine, 1944
All of the following papers were published by Scheele within a span of fifteen years.[2]
Scheele's papers appeared first in the Transactions of the Swedish Academy of Sciences, and in various periodicals such as Lorenz Florenz Friedrich von Crell's Chemische Annalen. Scheele's work was collected and published in four languages beginning with Mémoires de Chymie by Mme. Claudine Picardet in 1785 and Chemical Essays by Thomas Beddoes in 1786, followed by Latin and German.[24]
Another English translation was published by Dr Leonard Dobbin, in 1931.[25]
^p101, A Source Book in Chemistry, 1400–1900, Henry Marshall Leicester, Herbert S. Klickstein – 1969
^J. R. Partington (1962). A History of Chemistry, vol. 3. Macmillan. pp. 205–236.
^J. R. Partington (1962). A History of Chemistry, vol. 3. Macmillan. pp. 219–220.
^Scheele's laboratory notebooks show that during 1771–1772, he observed a "besondere Erde" (peculiar earth [i.e., metal oxide]) in pyrolusite (an ore that contains mainly manganese dioxide, MnO2). See: Scheele, Carl Wilhelm (1892). Nordenskiöld, A.E. (ed.). Carl Wilhelm Scheele: Nachgelassene Briefe und Aufzeichnungen [Carl Wilhelm Scheele: Posthumously published letters and notes] (in German and Latin). Stockholm: P.A. Norstedt & Söner. p. 457. From p. 457: "In Gewächsen muss die besondere Erde, welche aus magn. nigra et acidis … mit acido vitrioli ein solches Præcipitat." (In plants, [there] must be present the peculiar earth [i.e., metal oxide], which arises from magnesia nigra [i.e., pyrolusite] and acid via precipitation with oil of vitriol [i.e., concentrated sulfuric acid], for plant ash which is well rinsed so that all potassium sulfate disappears, gives – [when it's] dissolved with nitric acid and salt acid [i.e., hydrochloric acid] – such a precipitate [when it's treated] with sulfuric acid.) See also pp. 455, 456, and 461.
In 1774, Scheele further investigated barium in pyrolusite: Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On brown-stone [i.e., pyrolusite] or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden]) (in Swedish). 35: 89–116. From p. 102: "4:to Något af en ny Jord-art, hvilken, så mycket jag vet, ännu är obekant." (4th Something of a new type of ore [i.e., mineral], which, as far as I know, is still unknown.) From p. 112: "Den besynnerliga Jord-arten, som visar sig vid alla klara uplösningar af Brunstenen, hvarom något är anfördt i 18. §." (This peculiar type of ore [i.e., mineral] appears in all clear solutions of brown-stone, concerning which something is stated in section 18.)
^Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On brown-stone [i.e., pyrolusite] or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden]) (in Swedish). 35: 89–116.
^Scheele, Carl Wilhelm (1778). "Försök med Blyerts, Molybdæna" [Experiment with lead, molybdæna]. Kongliga Vetenskaps Academiens Handlingar (in Swedish). 39: 247–255.
^Scheele, Carl Wilhelm (1781). "Tungstens bestånds-delar" [Tungsten's constituent components]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Sciences [of Sweden]) (in Swedish). 2: 89–95.
^Scheele, Carl Wilhelm (1784). "Anmärkning om Citron-Saft, samt sätt att crystallisera den samma" [Note on lemon juice, as well as ways to crystallize the same]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 5: 105–109.
^ abScheele, Carl Wilhelm (1780). "Om Mjölk och dess syra" [About milk and its acid]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 1: 116–124.
^ abScheele, Carl Wilhelm (1783). "Rön beträffande ett särskilt Socker-Ämne uti exprimerade Oljor och Fettmor" [Findings concerning a particular sweet substance in expressed oils and fatty substances]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 4: 324–329.
Scheele, Carl W. (1782). "Försök, beträffande det färgande ämnet uti Berlinerblå" [Experiment concerning the coloring substance in Berlin blue]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science [of Sweden] (in Swedish). 3: 264–275.
Reprinted in Latin as: Scheele, Carl Wilhelm; Schäfer, Gottfried Heinrich, trans. (1789). "De materia tingente caerulei berolinensis". In Hebenstreit, Ernst Benjamin Gottlieb (ed.). Opuscula Chemica et Physica [Chemical and Physical Works] (in Latin). Vol. 2. Leipzig (Lipsiae), (Germany): Johann Godfried Müller. pp. 148–174.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Scheele (1771) "Undersŏkning om fluss-spat och dess syra" (Investigation of fluorite and its acid), Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Academy of Science [of Sweden]), 32 : 129–138.
^Scheele, Carl Wilhelm (1777). Chemische Abhandlung von der Luft und dem Feuer [Chemical treatise on air and fire] (in German). Upsala, Sweden: Magnus Swederus. pp. 149–155. See: § 97. Die stinckende Schwefel Luft (The stinking sulfur air [i.e., gas]).
^Scheele, Carl Wilhelm (1782). "Anmärkningar om sättet att conserva ättika" [Notes on the way to preserve vinegar]. Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science) (in Swedish). 3: 120–122.
Scheele (1774). "Om brunsten, eller magnesia, och dess egenskaper" [On pyrolusite or magnesia, and its properties]. Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden] (in Swedish). 35: 89–116. On pages 93–94 (paragraph 6), "Med den vanliga Salt-syran." ([Reactions of manganese dioxide] with the standard salt-acid [i.e., hydrochloric acid]), Scheele describes a gas (chlorine) that was produced when he reacted manganese dioxide with hydrochloric acid. Further experiments with chlorine appear in paragraphs 23–26, pp. 105–110.
An English translation of the relevant passages about chlorine from Scheele's article appears in: Leicester, Henry M. (1952). A Source Book in Chemistry, 1400–1900. New York, New York, USA: McGraw-Hill. pp. 109–110. ISBN9780674822306.
^Scheele, Carl Wilhelm (1778). "Tilrednings-saettet af en ny groen Faerg" [Method of preparation of a new green color]. Kungliga Vetenskaps Akademiens Handlingar (in Swedish). 39: 327–328.
^Ferguson, John. "Karl Wilhelm Scheele". Encyclopaedia Britannica. 1902. Retrieved 8 December 2017.
^Journal of the Chemical Society: obituaries (L Dobbin), 1952
Cardwell, D.S.L. (1971). From Watt to Clausius: The Rise of Thermodynamics in the Early Industrial Age. Heinemann: London. pp. 60–61. ISBN0-435-54150-1.
Dobbin, L. (trans.) (1931). Collected Papers of Carl Wilhelm Scheele. G. Bell & Sons, London.
Farber, Eduard, ed. (1961). Great Chemists. New York: Interscience Publishers. pp. 255–261.
Greenberg, Arthur. (2003). The Art of Chemistry: Myths, Medicines and Materials. Hoboken: John Wiley & Sons, Inc. pp. 161–166. ISBN0-471-07180-3.
Schofield, Robert E (2004). The Enlightened Joseph Priestley: A Study of His Life and Work from 1773–1804. Pennsylvania: The Pennsylvania State University Press. ISBN0-271-02459-3.
