Carl Wilhelm Scheele was a Swedish Pomeranian and pharmaceutical chemist.
Isaac Asimov called him "hard-luck Scheele" because he made a number of
chemical discoveries before others who are generally given the credit. For
example, Scheele discovered oxygen, and identified molybdenum, tungsten, barium,
hydrogen, and chlorine before Humphry Davy, among others. Scheele discovered
organic acids tartaric, oxalic, uric, lactic, and citric, as well as
hydrofluoric, hydrocyanic, and arsenic acids. He preferred speaking German to
Swedish his whole life, as German was commonly spoken among Swedish
pharmacists. Biography
Scheele was born in Stralsund, in western Pomerania, which was at the time
part of Sweden. Scheele's father Joachim Christian Scheele, was a grain dealer
and brewer from a respected German family. His mother was Margaretha
Eleanore Warnekros. Friends of Scheele's parents taught him
the art of reading prescriptions and the meaning of chemical and pharmaceutical
signs. Then, in 1757, at age fourteen Carl was sent to Gothenburg as an
apprentice pharmacist with another family friend and apothecary.. 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. Much of Scheele's later
theoretical speculations were based upon Stahl.
In 1765 Scheele worked under the progressive and well informed
apothecary, C. M. Kjellström in Malmö, and became acquainted with Anders Jahan
Retzius who was a lecturer at the University of Lund and later a professor
of chemistry at Stockholm. Scheele arrived in Stockholm between 1767 and
1769 and worked as a pharmacist. During this period he discovered tartaric acid
and with his friend, Retzius, studied the relation of quicklime to calcium
carbonate. While in the capital, he also became acquainted with many luminaries,
such as: Abraham Bäck, Peter Jonas Bergius, Bengt Bergius and Carl
Friedreich von Schultzenheim. In the fall of 1770 Scheele became
director of the laboratory of the great pharmacy of Locke, at Uppsala which is
about 40 miles 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 which which produced a red vapor. Further study of
this reaction later led to Scheele's discovery of oxygen. Based upon this
friendship and respect Scheele was given free use of Bergman's laboratory. Both
men 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 February 4, 1775. 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.
On October 29, 1777, Scheele took his seat for the first, and only time, at a
meeting of the Academy of Sciences and on November 11 passed the examination as
apothecary before the Royal Medical College and did so with 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.
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 saltpeter, 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 Lavoisier had already published their experimental data and
conclusions concerning oxygen and the phlogiston theory. 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".
The theory of phlogiston Scheele achieved astonishingly prolific
and important results without the expensive laboratory equipment to which
his Parisian contemporary Antoine-Laurent Lavoisier was
accustomed. Through the studies of Lavoisier, Joseph 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.
Scheele's study of the gas not yet named oxygen was prompted by a complaint by
Torbern Olof Bergman, a professor at Upsala 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
when it came into contact with acetic acid. Scheele's quick explanation was
that the saltpeter had absorbed phlogiston with the heat and gave off a
new phlogisticated gas as an active principle when combined with an acid.
Bergman next suggested that Scheele analyze the properties of manganese
dioxide. It was through his studies of manganese dioxide that Scheele developed
his concept of "fire air". 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 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.
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 plus heat. Scheele speculated
that his fire air or oxygen combined with the phlogiston in objects to
produce either light or heat. 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, and that when added to iron, water
was reproduced, which added weight to the iron as rust.
New elements and compounds In addition to his joint recognition for
the discovery of oxygen, Scheele is argued to have been the first to
discover other chemical elements such as barium, manganese, molybdenum, and
tungsten, as well as several chemical compounds, including citric acid, lactic
acid, glycerol, hydrogen cyanide, hydrogen fluoride, and hydrogen sulfide.
In addition, he discovered a process similar to pasteurization, along with a
means of mass-producing phosphorus, leading Sweden to become one of the
world's leading producers of matches. 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 given
to him by his friend, Johann Gottlieb Gahn, but could not identify an
additional component. When he treated the pyrolusite with hydrochloric acid
over a warm sand bath, a yellow-green gas with a strong odor was produced. 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". Eventually, Sir Humphry Davy named the gas chlorine.
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 in the hands of Labarraque, by
1824. Death
In the fall of 1785, Scheele began to suffer from symptoms described as kidney
disease. In early 1786, he also contracted a disease of the skin, which,
combined with kidney problems, so enfeebled him that he could foresee an
early death. With this in mind, he married the widow of his predecessor,
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. Scheele had a bad habit of sniffing and tasting
any new substances he discovered. Cumulative exposure to arsenic, mercury,
lead, their compounds, and perhaps hydrofluoric acid which he had
discovered, and other substances took their toll on Scheele, who died at the
early age of 43, on 21 May 1786, at his home in Köping. Doctors said that he
died of mercury poisoning. Published papers
All of the following papers were published by Scheele within a span of
fifteen years. See also
Scheelite Scheele's Green
Pharmacist Pharmacy
Pneumatic chemistry List of independent discoveries
Notes References
Abbott, David.. Biographical Dictionary of Scientists: Chemists. New York: Peter
Bedrick Books. pp. 126–127. ISBN 0-911745-81-5.
Bell, Madison S.. Lavoisier in the Year One. New York: W.W. Norton & Company,
Inc. ISBN 0-393-05155-2. Cardwell, D.S.L.. From Watt to Clausius:
The Rise of Thermodynamics in the Early Industrial Age. Heinemann: London. pp.
60–61. ISBN 0-435-54150-1. Dobbin, L.. Collected Papers of Carl
Wilhelm Scheele. G. Bell & Sons, London. Farber, Eduard ed.. Great Chemists. New
York: Interscience Publishers. pp. 255–261.
Greenberg, Arthur.. A Chemical History Tour: Picturing Chemistry from Alchemy
to Modern Molecular Science. Hoboken: John Wiley & Sons, Inc. pp. 135–137.
ISBN 0-471-35408-2. Greenberg, Arthur.. The Art of
Chemistry: Myths, Medicines and Materials. Hoboken: John Wiley & Sons,
Inc. pp. 161–166. ISBN 0-471-07180-3. Schofield, Robert E. The Enlightened
Joseph Priestley: A Study of His Life and Work from 1773-1804. Pennsylvania:
The Pennsylvania State University Press. ISBN 0-271-02459-3.
Shectman. Groundbreaking Scientific Experiments, Inventions, and Discoveries
of the 18th Century. Connecticut: Greenwood Press. ISBN 0-313-32015-2.
Sootin, Harry. 12 Pioneers of Science. New York: Vanguard Press.
External links Works by Carl Wilhelm Scheele at Project
Gutenberg Works by or about Carl Wilhelm Scheele
at Internet Archive Scheele, Chemical Observations and
Experiments on Air and Fire Excerpts from the Chemical Treatise on
Air and Fire "Scheele, Karl Wilhelm". Encyclopædia
Britannica. 1911. Carl Wilhelm Scheele's d. Königl.
Schwed. Acad. d. Wissenschaft Mitgliedes, Chemische Abhandlung von der
Luft und dem Feuer in German "Scheele, Carl Wilhelm". The Nuttall
Encyclopædia. 1907. "Sketch of Karl Wilhelm Scheele".
Popular Science Monthly 31: 839–843. October 1887.
"The Scheele Monument at Stockholm". Popular Science Monthly 42: 685–688.
March 1893.