From 1804-1810 Mitscherlich attended Mariengymnasium Jever, where he was much influenced by one of his teachers, the historian F. C. Schlosser.
College/University
Gallery of Eilhard Mitscherlich
Unter den Linden 6, 10117 Berlin, Germany
In the spring of 1818, Mitscherlich decided to go to Berlin in preparation for an academic career in chemistry. There he was warmly supported by H. F. Link, a botanist, chemist, and expert in Eastern languages. He also befriended the mineralogist Gustav Rose, who taught him the basics of crystallography.
Gallery of Eilhard Mitscherlich
Solnavägen 1, 171 77 Solna, Sweden
In 1819 Mitscherlich received a government grant to enable him to continue his studies in Berzelius' laboratory at the Karolinska Institutet in Stockholm. Mitscherlich returned to Berlin in 1821.
Gallery of Eilhard Mitscherlich
69117 Heidelberg, Germany
On the advice of Schlosser in 1811, Mitscherlich matriculated at the University of Heidelberg to study Arabic and Persian.
Gallery of Eilhard Mitscherlich
Wilhelmsplatz 1, 37073 Göttingen, Germany
After his hope to visit Persia as a member of a delegation that Napoléon Bonaparte had intended to send to the shah was frustrated, he began to study medicine in Göttingen, intending to become a physician on ships sailing to Asia. In Göttingen, he also took courses in physics and in chemistry with Friedrich Stromeyer.
Career
Gallery of Eilhard Mitscherlich
1856
Eilhard Mitscherlich portrait lithograph by Rudolf Hoffmann.
Gallery of Eilhard Mitscherlich
Invalidenstraße 43, 10115 Berlin, Germany
Marble bust of Mitscherlich by Elisabet Ney at the Museum für Naturkunde in Berlin.
Gallery of Eilhard Mitscherlich
Eilhard Mitscherlich portrait engraving by W.C.Sharpe.
Gallery of Eilhard Mitscherlich
Oil portrait of Eilhard Mitscherlich.
Achievements
Unter den Linden 6, 10117 Berlin, Germany
Bronze statue of Mitscherlich at the Humboldt University of Berlin.
Membership
Royal Society
Eilhard Mitscherlich was a member of the Royal Society.
Royal Prussian Academy of Sciences
Eilhard Mitscherlich was a member of the Royal Prussian Academy of Sciences (now Berlin-Brandenburg Academy of Sciences and Humanities).
German Academy of Sciences Leopoldina
Eilhard Mitscherlich was a member of the German Academy of Sciences Leopoldina.
Royal Swedish Academy of Sciences
Eilhard Mitscherlich was a member of the Royal Swedish Academy of Sciences.
Saint Petersburg Academy of Sciences
Eilhard Mitscherlich was a member of the Saint Petersburg Academy of Sciences.
American Academy of Arts and Sciences
Eilhard Mitscherlich was a member of the American Academy of Arts and Sciences.
French Academy of Sciences
Eilhard Mitscherlich was a member of the French Academy of Sciences.
Academy of Sciences of Turin
Eilhard Mitscherlich was a member of the Academy of Sciences of Turin.
After his hope to visit Persia as a member of a delegation that Napoléon Bonaparte had intended to send to the shah was frustrated, he began to study medicine in Göttingen, intending to become a physician on ships sailing to Asia. In Göttingen, he also took courses in physics and in chemistry with Friedrich Stromeyer.
In the spring of 1818, Mitscherlich decided to go to Berlin in preparation for an academic career in chemistry. There he was warmly supported by H. F. Link, a botanist, chemist, and expert in Eastern languages. He also befriended the mineralogist Gustav Rose, who taught him the basics of crystallography.
In 1819 Mitscherlich received a government grant to enable him to continue his studies in Berzelius' laboratory at the Karolinska Institutet in Stockholm. Mitscherlich returned to Berlin in 1821.
Ueber Das Verhältniss Zwischen Der Chemischen Zusammensetzung Und Der Krystallform Arseniksaurer Und Phosphorsaurer Salze: Uebersetzt Aus Dem Schwedischen
Eilhard Mitscherlich was a German chemist and mineralogist. He is best remembered today for his discovery of the phenomenon of crystallographic isomorphism in 1819.
Background
Eilhard Mitscherlich was born on January 7, 1794, in Neuende, Lordship of Jever (now Wilhelmshaven, Niedersachsen, Germany). His father, Karl Gustav Mitscherlich, was a minister and his mother, née Maria Elisabeth Eden, was the daughter of a small art dealer. His uncle, Christoph Wilhelm Mitscherlich, professor at the University of Göttingen, was in his day a celebrated scholar.
Education
From 1804-1810 Mitscherlich attended Mariengymnasium Jever, where he was much influenced by one of his teachers, the historian F. C. Schlosser. On the advice of Schlosser in 1811, he matriculated at the University of Heidelberg to study Arabic and Persian.
In 1813 Mitscherlich moved to Paris to continue his studies in Eastern languages. After his hope to visit Persia as a member of a delegation that Napoléon Bonaparte had intended to send to the shah was frustrated, he began to study medicine in Göttingen, intending to become a physician on ships sailing to Asia. In Göttingen, he also took courses in physics and in chemistry with Friedrich Stromeyer. Simultaneously with his medical studies, Mitscherlich completed the research on ancient Persian texts for which he was awarded the doctorate. In the spring of 1818, Mitscherlich decided to go to Berlin in preparation for an academic career in chemistry. There he was warmly supported by H. F. Link, a botanist, chemist, and expert in Eastern languages. He also befriended the mineralogist Gustav Rose, who taught him the basics of crystallography.
In 1819 Mitscherlich received a government grant to enable him to continue his studies in Berzelius' laboratory at the Karolinska Institutet in Stockholm. Mitscherlich returned to Berlin in 1821.
In 1818 Mitscherlich went to Berlin to work in the laboratory of the botanist Heinrieh Link. He observed that the crystals of potassium phosphate and potassium arsenate appeared to be nearly identical in form and, his curiosity spurred, asked Gustav Rose to instruct him in exact crystallographic methods so that he could make precise measurements. He then applied spherical trigonometry to the data that he obtained, and was thereby able to confirm his first impression. He reported this finding in an article entitled “Ueber die Krystallisation der Saltze, in denen das Metall der Basis mit zwei Proportionen Sauerstoff verbunden ist,” published in the Abhandlungen der Preussischen Akademie der Wissenschaften for 1818-1819 and translated into French for publication in the Annales de chimie in the following year.
In this important article Mitscherlich discussed the crystals of the sulfates of various metals. He demonstrated that these sulfates - as well as the double sulfates of potassium and ammonium - crystallize in like forms, provided that they bind the same quantity of water of crystallization. Thus, for sulfates of copper and manganese, he found the ratio between the oxygen of the oxide and that of the water of crystallization to be 1:5; while for zinc, nickel, and magnesium, the ratio is 1:7. He further stated his hope “that through crystallographic examination the composition of bodies will be determined with the same certainty and exactness as through chemical analysis.”
Mitscherlich met Berzelius in 1819 when the latter was passing through Berlin. Berzelius had heard of Mitscherlieh’s work and recognized the significance of his findings. When the Prussian Ministry of Education offered Berzelius the chair of chemistry at the University of Berlin, left vacant on the death of Klaprolh, Berzelius suggested appointing Mitscherlich in his stead. Mitscherlich was thought to be too young to fill the post, however, and a compromise was arranged whereby he would be sent to work with Berzelius in Stockholm for two years, in order to enlarge his knowledge of chemistry. In the course of this fruitful partnership, Mitscherlich worked in Berzelius’ laboratory, visited and studied the mines and metallurgical works at Falun, and acquired further experience in chemical analysis and inorganic chemistry. Most important, he continued his work on isomorphism.
In his second article on his crystallographic researches, “Om Förhållandet einellan Chemiska Sammansättningen och Krystallformen hos Arseniksyrade och Phosphorsyrade Salter” (“On the Relation Between the Chemical Composition and the Crystal Form of Salts of Arsenic and Phosphoric Acids”), published in Kungliga Svenska vetenskapsakademiens handlingar in 1822, Mitscherlich reported on new observations that he had made with Berzelius.
The statement of the law of isomorphism, made early in his career, marks Mitscherlich’s most important contribution to chemistry - indeed, Berzelius considered Mitscherlich’s discovery to be the most significant since that of chemical proportions. Berzelius himself found Mitscherlich’s work to be of great use; he was at this time concerned with the determination of the atomic weights of the elements and the law of isomorphism provided him with a valuable tool. Since the relative atomic weight of an element could be determined only through a knowledge of how many atoms are contained in the molecule, Berzelius’ task was simplified by the application of Mitscherlich’s law - once he had established the atomic composition of one of the isomorphic compounds, those of the others could be assumed to correspond to it. He was thus able to check the atomic weights that he had set out in his Lärbok i kemien of 1814 and presented corrected values for twenty-one elements in the second edition, which was published in 1826.
Mitscherlich refined his work on isomorphism from time to time throughout his scientific life. When it became clear that his original formulation of the law was too broad, he modified it (in 1832) to state more precisely that only certain elements can substitute for each other in crystal form. During the following years, too, Mitscherlich established the isomorphism that exists between a number of specific compounds, including sulfates, metallic selenates, potassium chromate and potassium manganate, and potassium perchlorate and potassium permanganate. All of his later work was conducted in Berlin, where he returned in 1822 to take up the post of assistant professor of chemistry at the university. He became full professor three years later. He was also a member of the Berlin Academy of Sciences and director of its laboratory, located in the observatory. He made extensive use of this installation for teaching as well as for research, since the university offered no facilities for practical instruction in chemistry.
Besides his sojourn in Sweden, Mitscherlich made other trips abroad to work with foreign scientists. In 1823-1824 he was in Paris, where he collaborated with Fresnel in investigating the alteration of the double refraction of crystals as a function of temperature; he also met Thenard and Gay-Lussac. In 1824 he visited Humphry Davy, Faraday, Wollaston, and Dalton in England, where he inspected a number of factories. Back in Berlin, he worked in a number of areas of both organic and inorganic chemistry, in addition to his studies of isomorphism.
Mitscherlich modified Dumas’s apparatus by employing a metal bath for measuring higher temperatures; he was thus able to determine the vapor densities of bromine, sulfur phosphorus, arsenic, mercury, sulfur trioxide, phosphorus pentachloride, calomel, and arsenic oxide. His results were highly accurate in most instances. He further measured the pressure of water vapor over Glauber’s salt, in response to a suggestion of Berzelius, who had hoped - erroneously - that a numerical indication of the affinity of water for various substances might be determined from the differences between the pressure of water vapor over those substances.
In organic chemistry, Mitscherlich in 1834 obtained benzene by the dry distillation of the calcium salt of benzoic acid. He found the product of the distillation to be identical with the “bicarburet of hydrogen” that Faraday had isolated from compressed oil-gas five years earlier. From his observation that benzoic acid might be a compound of benzene and carbon dioxide, Mitscherlich concluded that all organic acids must consist of hydrocarbons plus carbonic acid - a misconception that was long perpetuated.
Mitscherlich went on to conduct experiments on various benzene derivatives. He obtained nitrobenzene from the reaction of benzene with fuming nitric acid (ordinary nitric acid does not react with benzene) and benzenesu1fonic acid from the reaction of benzene with fuming sulfuric acid. He also obtained azobenzene, trichlorobenzene, hexachlorobenzene, and their corresponding bromine derivatives.
In 1834 Mitscherlich also showed that a mixture of ether and water distills out of a mixture of alcohol and diluted sulfuric acid; he suggested that in this case, the sulfuric acid acts as a dehydrating agent. From this observation, he developed his contact theory, whereby certain chemical reactions can take place only in the presence of certain other substances. Mitscherlich’s theory was a direct predecessor of Berzelius’ catalyst theory, which was, in fact, a refinement of it.
In his experiments on fermentation Mitscherlich further discovered that yeast does not act directly on cane sugar; instead, an invert sugar, a kind of levorotatory “modified cane sugar” identical to the sugar formed by the action of acids on cane sugar, is formed first. He also established that 0.001 percent acid is sufficient to invert sugar solutions. He gave impetus to the sugar industry both by developing the first practical polarization apparatus and by devising a method to control polarization through polarimetric analysis.
Mitscherlich worked to improve the methods and accuracy of both organic and inorganic analytical chemistry. In 1855 he developed a toxicological detection index for white phosphorus, by which the substance to be tested was distilled with steam and the presence of phosphorus determined by luminescence in the condenser of the distilling apparatus. He was also the first to employ a mixture of potassium carbonate and sodium carbonate to produce fusion. For analyzing organic compounds, Mitscherlich constructed a combustion apparatus that differed from those of Berzelius and Liebig in that the combustion tube was heated by a spirit lamp, rather than by burning charcoal. The oxygen produced by the potassium chlorate was used to regenerate cupric oxide. Liebig, who was never on very good terms with Mitscherlich, pronounced the apparatus to be of little value.
In his last years, Mitscherlich made a number of journeys to the most important European volcanoes to gather data toward a general theory of volcanoes, the subject of his last, posthumously published, articles. (It must be noted, however, that his work in volcanology produced little of significant value.)
Mitscherlich was perhaps most successful as a writer of textbooks. His Lehrbuch der Chemie was first published in 1829; by 1847 it had had four new editions in German, as well as two editions in French and one in English. The work contained Mitscherlich’s lectures on all aspects of pure and applied chemistry, as well as a considerable amount of material on physics, all illustrated with a number of beautiful woodcuts. The lectures themselves are characterized by their exemplary clarity and ingenious experiments; the book was highly praised by Mitscherlich’s contemporaries, including Berzelius and Liebig. As a teacher, Mitscherlich was aware that his students needed practical instruction; although his efforts to this end were in fact little more than perfunctory, he did take them on visits to factories.
Eilhard Mitscherlich was born to the family of a minister. Marriage and Baptism records show that he was Lutheran.
Politics
Nothing is known about Mitscherlich's political stance.
Views
Mitscherlich was the first to recognize the phenomenon now called dimorphism. In his next paper, “Über die künstliche Darstellung der Mineralien aus ihren Bestandtheilen,” published in Abhandlungen der Preussischen Akademie der Wissenschaften for 1822-1823, he investigated this phenomenon in greater detail and presented a number of examples, including the rhombic and monoclinic forms of sulfur. (He thus refuted Haüy’s crystallographic axiom, whereby crystal angles, particularly the angles of cleavage, are characteristic of a given substance.)
In inorganic chemistry, Mitscherlich investigated the higher compounds of manganese, including the mixture of manganate and permanganate that Glauber, in the seventeenth century, had called the “chameleon mineral.” Mitscherlich offered an explanation for the transformations of this substance, establishing that its red and green salts are the derivatives of two different (manganic and permanganic) acids; he determined their chemical composition in 1830. Aschoiff produced the anhydride of permanganic acid in Mitscherlich’s laboratory, and Mitscherlich himself was the first to obtain iodine azide and selenic acid.
During the same period, Mitscherlich was also concerned with vapor-density determinations.
Mitscherlich’s early interest in geology and mineralogy continued throughout his life. He was particularly concerned with the production of artificial minerals through the fusion of silica with various metallic oxides and achieved some valuable results in such experiments.
Quotations:
"Every arsenate has its corresponding phosphate, composed according to the same proportions, combined with the same amount of water of crystallization, and endowed with the same physical properties: in fact, the two series of salts differ in no respect, except that the radical of the acid in one series in phosphorus, while in the other it is arsenic."
Membership
Eilhard Mitscherlich was a member of the Royal Society, the Royal Prussian Academy of Sciences (now Berlin-Brandenburg Academy of Sciences and Humanities), the German Academy of Sciences Leopoldina, the Royal Swedish Academy of Sciences, the Saint Petersburg Academy of Sciences, the American Academy of Arts and Sciences, the French Academy of Sciences, and the Academy of Sciences of Turin.
Royal Society
,
United Kingdom
Royal Prussian Academy of Sciences
,
Germany
German Academy of Sciences Leopoldina
,
Germany
Royal Swedish Academy of Sciences
,
Sweden
Saint Petersburg Academy of Sciences
,
Russia
American Academy of Arts and Sciences
,
United States
French Academy of Sciences
,
France
Academy of Sciences of Turin
,
Italy
Interests
eastern languages, Persian language
Connections
Eilhard Mitscherlich was married to Laura Amanda Meyer. They had two daughters, Clara Louis and Agnes Sophie Friedericke, and three sons Richard, Gustav Alfred, and Alexander.