Jons Jakob Baron Berzelius
Berzelius, Jöns Jacob
Berzelius, Jöns Jacob
(b. Väversunda, Östergötland, Sweden, 20 August 1779; d. Stockholm, Sweden, 7 August 1848)
Berzelius came from an old Swedish family. A number of his ancestors had been clergymen. His father, Samuel, a teacher in the Linköping Gymnasium, died when his son was four years old. The mother, Elizabeth Dorothea, two years later married Anders Ekmarck, the pastor at Norrköping and himself the father of five children. Young Berzelius and his sister were raised with the Ekmarck children and educated by Ekmarck and private tutors. In 1788 Berzelius’ mother died and within two years Ekmarck remarried. The two Berzelius children were sent to the home of their maternal uncle, Magnus Sjösteen. Young Jöns and his cousins quarreled frequently. Even after he entered the Linköping Gymnasium in 1793 conflicts continued, and to escape them Berzelius took a position in 1794 as tutor on a nearby farm, where he developed a strong interest in collecting and classifying flowers and insects. He had originally intended to become a clergyman, but he instead chose to develop his interest in natural science and decided on a career in medicine. Two years later he began his medical studies at Uppsala, but had to interrupt his work to earn money as a tutor. Fortunately, in 1798 he received a three-year scholarship which permitted him to continue his medical studies.
At this time his oldest stepbrother introduced him to chemistry, of which Jöns knew nothing. Together they studied Girtanner’s Anfangsgründe der antiphlogistischen Chemie. Thus in his first studies Berzelius learned of the new chemistry which had not yet had much influence on the older Swedish chemists. The professor of chemistry at Uppsala, Johan Afzelius, did not offer much encouragement to Berzelius who therefore began to carry out experiments in his own quarters. During the next summer, lacking any financial support, he intended to stay at the home of an aunt, but her husband did not approve of the young man and sent him to work in a pharmacy at Vadstena. Here he was able to learn glassblowing. Later in the summer his uncle, to get rid of him, introduced him to Sven Hedin, chief physician at the Medevi mineral springs. He took Berzelius as his assistant for the summer of 1800. There he began his scientific career by analyzing the mineral content of the spring water. At the same time he read of the newly described voltaic pile, the first reliable source of a continuous electric current. He soon built one for himself from sixty pairs of alternating zinc disks and copper coins. In 1802 he used the knowledge thus gained in his doctoral thesis, a study of the effect of the galvanic current on patients with a number of different diseases. He found that the current had no effect on the patients, but his interest in electrical phenomena remained strong.
Sven Hedin was aware of Berzelius’ interest in chemistry and soon after the latter’s medical degree was granted, Hedin arranged for his appointment as an unpaid assistant to the professor of medicine and pharmacy at the College of Medicine in Stockholm. His duties involved the preparation of artificial mineral waters. He lived in a house owned by Wilhelm Hisinger, a wealthy mine owner with a great interest in mineralogy and chemistry. Berzelius soon began to undertake serious chemical investigations with Hisinger. The electrochemical and mineralogical investigations that the two enthusiasts carried out laid the foundations for Berzelius’ future work.
Meanwhile, Berzelius became involved in serious financial difficulties. His only income came from his position as physician to the poor in several Stockholm districts, and the salary was very low. Business ventures that he attempted turned out disastrously, and he was deep in debt. His position improved in 1807 when the professor of medicine and pharmacy died and he was appointed to the post. He now had an increased salary and access to a laboratory. In this period he began to work on the textbooks whose composition strongly influenced the direction of his later career. In 1810 the Medical College became the Karolinska Institutet, an independent medical school, and Berzelius was able to devote most of his time to chemistry. He became a member of the Swedish Academy of Science in 1808 and its president in 1810.
During this time Berzelius began the series of travels abroad through which he became personally acquainted with almost all of the leading chemists of his day. In 1807 he met Hans Christian Oersted, the noted discoverer of electromagnetism. In 1812 he visited England and met all the important British chemists. He was especially anxious to meet Humphry Davy, whose electrochemical researches had been closely related to those of Berzelius and Hisinger. At first Davy and Berzelius got on well, but later some of Berzelius’ criticisms of one of Davy’s books were reported indirectly to Davy and a coolness developed between the two which was never entirely eliminated. In 1818 Berzelius visited Paris, where he remained for a year, meeting his French colleagues. He spent a part of his time working with Dulong at the home of Berthollet in Arcueil. On his way back to Stockholm he traveled through Germany, where he met the most prominent German chemists. He created such a strong impression there that he was later followed to Sweden by a number of younger chemists who wished to work in his laboratory. These included Eilhard Mitscherlich and Gustav and Heinrich Rose. Friedrich Wöhler, who spent a year (1823–1824) with Berzelius, maintained a close personal friendship with him for the rest of his life, translating many of his important works into German.
While he was in France, Berzelius was elected secretary of the Swedish Academy of Science. This doubled his income and furnished him with an excellent laboratory. He was able to devote himself almost entirely to his laboratory research and to his voluminous writings, including correspondence with scientists all over Europe. He became the recognized authority on chemical questions, although he became involved in a number of polemics, especially with Dumas and Liebig.
Berzelius suffered from poor health through much of his life. He was subject to severe periodic headaches which occurred regularly each month at the time of the new and full moon. In later life these disappeared, but were replaced by attacks of gout and periods of prolonged depression and apathy which interfered with his scientific work. Feeling the need for a more domestic life, he finally decided he should marry, and so in 1835, at the age of fifty-six, he married Elizabeth Poppius, the twenty-four-year-old daughter of one of his old friends. On this occasion the king of Sweden gave him the title of baron. The marriage, which was childless, eased the remaining years of his life.
As he grew older, he became more and more set in his ideas, refusing to accept the newer developments in chemistry which contradicted some of his own theories. He withdrew more and more from the laboratory and spent much time trying to discredit the ideas which the growth of the new field of organic chemistry was forcing upon younger chemists. The last years of his life were not happy ones. At the time of his death he had become a respected figure, but one whose opinions were generally disregarded by his younger colleagues.
Berzelius’ most active and productive years were those in which chemistry was beginning to show the full effects of Lavoisier’s revolution. The fundamental tools which he created were extremely influential in determining the direction in which the science developed. His achievements were many and varied, and at first glance they seem rather unrelated to each other. Upon closer examination we find an underlying unity of thought and a logical interconnection and development of this thought in most of his work.
He was almost self-taught in chemistry. His first textbook adhered to the antiphlogistic viewpoint. The theories of Lavoisier came late to Sweden, but Berzelius never learned the theory of phlogiston. From the time of one of the earliest experiments that he carried out in his rooms, the preparation of oxygen, he was a firm believer in the essential participation of this element in the constitution of chemical compounds. His first scientific papers were rejected for publication by the Academy because he used the antiphlogistic nomenclature. Berzelius was also heir to the chemical work of his own countrymen. The systematization of chemistry and the interest in the nature of chemical affinity which were characteristic of the work of Torbern Bergman as well as the discovery of new minerals and elements carried out by Scheele and other Scandinavian chemists were certainly influential in determining the direction of Berzelius’ theoretical and laboratory studies. These men bad developed mineral analysis to a high degree and it is not strange that one of the, first pieces of chemical work by Berzelius was the analysis of the composition of Medevi mineral waters.
Aside from these influences of older workers, Berzelius was always keenly aware of the importance of the current literature. He studied it carefully, making critical surveys at first for his own use and later for the benefit of all chemists. His earliest book, published in 1802, was a treatise on galvanism, a review of all the work done up to that time on the action of electricity on salts and minerals. This reflected his early appreciation of the importance of the voltaic pile. It showed his ability to synthesize the literature, and it formed the basis for his pioneering studies with Hisinger.
His association with Hisinger during the first decade of the nineteenth century was particularly fruitful. Through this association Berzelius gained access to the largest voltaic pile in Sweden, owned by the Galvanic Society, of which Hisinger was a leading member. In 1803 Hisinger and Berzelius published the results of their studies on the action of the electric current on, a number of sodium, potassium, ammonium, and calcium salts. They found that all the salts were decomposed by electricity. Oxygen, acids, and oxidized bodies accumulated at the positive pole, while combustible bodies, alkalies, and alkaline earths passed to the negative pole. Some acids were converted to a lower oxidation state and passed to the negative pole. Thus the lower oxidation state represented a “combustible body.” Similar results were obtained and extended by Humphry Davy in England in the years from 1806 to 1807 and led him to the isolation of the alkali and alkaline earth metals. Berzelius with his friend Pontin also continued this type of work, and in 1808 introduced the use of mercury as the negative electrode. This permitted obtaining amalgams of the metals and even ammonium amalgam.
These studies aroused the interest of Berzelius and Davy in each other and was one of the reasons Berzelius visited England in 1812. More important, they convinced him of the significance of electricity in binding chemical elements together and also strengthened his conviction, gained from reading Lavoisier, that oxygen was an essential constituent not only of all acids, hut also of bases as well. From these ideas he was later to develop his dualistic theory of the nature of salts.
Hisinger was not solely interested in electrochemical studies. He had also been interested since boyhood in the minerals found in and around his mines. He had had analyses made of a number of minerals that he had collected, and he himself had analyzed a number of them. Among his minerals was a very heavy stone found near the iron mine of Bastnäs, in which Scheele bad vainly tried to find tungsten. Since Berzelius had been carrying out mineral analyses, Hisinger proposed that they should study this mineral together. In 1803 they found that it contained a new element which they named cerium. This was discovered at the same time by Klaproth in Berlin.
While these studies were in progress, Berzelius was acting as assistant in medicine at the School of Medicine in Stockholm. In the course of his work he realized that there were no adequate Swedish textbooks on chemical subjects, and so he decided to prepare such texts himself. The first of these was a book on animal chemistry, published in 1806, which included the results of numerous analyses he had made on animal tissues and fluids. In the course of this work he noted that muscle tissues contain lactic acid, previously found by Scheele in milk. He developed an interest at this time in organic acids, which he later studied in greater detail. After completion of this text, Berzelius turned to the composition of a general textbook of chemistry, and in 1808 he published the first volume of his Lärbok i kemien, which was destined to become the most authoritative chemical text of its day. While he was writing it, problems occurred to Berzelius and the search for solutions to these led him to carry out much of the research which occupied his most productive period.
At this time chemists were still debating the questions of whether chemical compounds had a fixed composition. The Berthollet-Proust controversy had nearly been decided in favor of the Proustian view that the composition of salts was invariant, but the actual evidence in support of this view was far from conclusive, largely because of the inadequate number of analyses of salts that existed, and the inaccuracies of many of the analyses which did exist. Furthermore, there was no theoretical reason for assuming, a fixed composition. The Berthollet-Proust controversy had Berzelius studied the work of Jeremias Benjamin Richter, who in 1792 had published a work on stoichiometry in which he reported measurements of the amounts of various acids required to neutralize certain bases and of bases to neutralize acids. The work actually demonstrated the law of constant proportions. Berzelius saw that his own analyses, so far as they bad been carried, also agreed with this law. He decided to devote himself to the analysis of a large number of salts to confirm or disprove this law. At just this time he learned, of the atomic theory of Dalton, which supplied a theoretical basis for the law. Berzelius now realized that he did not yet possess the information needed to complete the second volume of his textbook. For the next four years he carried on his analytical studies and finally summarized them in the second volume, which appeared in 1812. In every subsequent edition he presented further results of his continuing analytical studies. In the meantime, he published many of them in the Afhandlingar i fysik kemi och mineralogi, a journal which Hisinger had founded in 1806 because neither he nor Berzelius were satisfied with the brief form required by the Academy for publication of papers in its Proceedings. Berzelius took over publication of later volumes of this journal, and it continued to appear until 1818 when he became secretary of the Academy and could himself have an influence on its policies. Most of Berzelius’ important papers were also published in foreign journals, and the various editions of his textbook appeared in German, French, Dutch, Italian, and Spanish; Wöhler’s German translations were especially helpful in making his ideas known abroad.
The scientific apparatus and reagents available in Sweden when Berzelius began his work were very inadequate. In consequence, he had to design and build almost everything he needed and to synthesize most of his own reagents. The new forms of apparatus that he built were described in the various editions of his textbook and became standard pieces of equipment in laboratories all over the world. He was especially skillful in the use of the blowpipe, which had been developed in the Scandinavian countries. He utilized it in many of his analytical procedures, and the book that he wrote concerning it popularized its use abroad. It was not until his visit to Paris in 1818 that he was able to secure better materials for his laboratory; he sent home twelve large packing cases of apparatus.
Not only did Berzelius have to design his apparatus, but he also had to work out new analytical methods, and in the planning of such methods he showed his chemical genius. He spent much time in the preliminary work for each analysis, so that when he performed the analysis itself he was sure of his results and seldom felt the need to repeat the work.
He set himself the task “to find the definite and simple proportions in which the constituents of inorganic nature are bound together.” In general he based his work on oxygen compounds. His conviction of the importance of oxides had begun with his studies of Lavoisier’s work and had been strengthened by his electrochemical experiments. He determined the ratio of metal to oxygen in a number of metallic oxides by reducing the oxide to the metal with hydrogen, or sometimes by converting the metal to its oxide. Similarly he determined the oxygen to sulfur ratio in sulfur dioxide and trioxide. From these results she went on to analyses of sulfates and other salts. He reported his analyses in terms of the positive and negative components; for example, for calcium sulfate as CaO and SO3. This method of reporting analytical results was long continued by analytical chemists. To his great delight all his analyses fitted into his original assumption of the validity of the law of constant proportions. His results permitted him to determine the atomic weights of the elements he studied, although at first he had no way of determining whether a given value or some multiple of it represented the true atomic weight. When Dulong and Petit in 1819 announced the law that the product of atomic weight and specific heat is a constant, Berzelius recognized that he had a new tool for his purpose, and when Mitscherlich, who later studied with him, published the law of isomorphism in 1820, he saw another. By applying these laws to his own results, he was able to correct his values, and only in the case of the alkali metals did he finally accept values that were double the correct ones. He published revised tables of atomic weights in 1814, 1818, and 1828, and a separate pamphlet was issued in French in 1819 to give wider circulation to his values. In the 1818 table he reported the atomic weights of forty-five of the forty-nine elements then known. Thirty-nine of the determinations were his; the other six were by his students. The table included the chemical composition of nearly 2,000 compounds.
This work with so many salts of so many elements brought home to him the need for a simple and logical system of symbols to represent the compounds he discussed. His first publication in this, field was a pamphlet in French issued, in 1811, and he explained his ideas in German and English papers published over the next three years. His basic suggestion was that as the symbol for each element the first letter of the Latin name be chosen, or, if more than one element began with the same letter, the next letter of the name be added to the initial for one of them. The use of letters to represent the names of elements and compounds was not entirely new, but Berzelius introduced a new quantitative concept with his symbols. The letter stood for the atomic weight of the element as well, and so the chemical formulas of the compounds of these elements represented the chemical proportions of the elements in that compound. To indicate these proportions he wrote the appropriate small numbers in the formulas. He placed the numbers as superscripts resembling algebraic exponents in these formulas(e.g., SO3), a practice that continued to be used in France, although elsewhere the numbers came to be written as subscripts. At first there was some opposition to the use of these formulas, but their advantages eventually came to be recognized and their use became universal. Berzelius later introduced certain modifications which he believed made the formulas simpler. Instead of writing O for oxygen he placed a dot for each oxygen atom above the symbol of the element combined with it, and for a double atom he placed a bar through the letter involved. Thus the symbol for water became Ḣ̶. Such formulas were not easily set in type, and these innovations did not survive for very long. The basic principles of the Berzelius system have served chemistry well, however.
In accord with the interest that Swedish chemists had long shown in mineralogical studies, Berzelius had from time to time analyzed minerals that came into his hands. As was noted above, the discovery of cerium was the result of such an analysis. However, when he began his systematic studies to establish the law of constant proportions, he worked largely with simple salts. In 1812 he received a gift of a large number of minerals which he later decided to classify. The methods of mineral classification existing at that time were based on appearance and physical properties. These seemed highly unsystematic to Berzelius. He concluded from his analytical experience that a logical classification could be based only on chemical composition. In his original system, first published in 1814, he arranged the minerals in terms of their basic constituents, although he later revised this and placed chief emphasis on the acid component. Like many of Berzelius’ innovations, his system of mineral classification was at first received with some hostility, but this was gradually overcome. During his visit to Paris in 1818 he won the approval of Haüy, the leading mineralogist of the day whose own system was based on physical properties.
Interest in the composition of inorganic substances and even of industrial wastes led to the discovery of a number of new elements in the Berzelius laboratory. He himself discovered selenium and thorium, while, as students working with him, Arfwedsen isolated lithium, Sefström found vanadium, and Mosander discovered a number of rare earth elements.
Berzelius was not only a brilliant laboratory experimenter. He constantly tried to bring together the isolated facts discovered by experiment and to produce a synthesis that could explain the basic problems of his science. The major synthesis of his career was his dualistic theory, by which he believed he had explained the long-discussed problem of the nature of the affinity that held chemical substances together. His analytical work furnished him with numerous examples of salts composed of acid and basic radicals, and his early electrochemical studies suggested to him the mechanism that he sought.
He had found that an electric current splits salts into positive and negative components. Berzelius believed in the two-fluid theory of electricity and he held that electricity was itself a substance. Therefore when a salt was split by a current, the negative electricity combined with the positive component of the salt, while the positive electricity combined with the negative component. This maintained electrical neutrality. When the electricities were not present, the negative and positive components of the salt would combine and neutralize each other. Berzelius built his theory by elaboration of these facts and ideas. He believed that one pole of a magnet could be stronger than the other, and similarly the electricity in a substance might be concentrated at one point in it, leading to a predominance at that point of either negative or positive electricity. This condition of unipolarity determined the electrical behavior of the substance. The intensity of the polarity was another important factor, since the more intense the polarity, the stronger would be the affinity for another substance which would neutralize it. Thus, as he said,
…every chemical combination is wholly and solely dependent on two opposing forces, positive and negative electricity, and every chemical compound must be composed of two parts combined by the agency of their electrochemical reaction, since there is no third force. Hence it follows that every compound body, whatever the number of its constituents, can be divided into two parts, one of which is positively and the other negatively electrical [Essai sur la théorie des proportions chimiques (1819), p. 98].
Berzelius arranged all the elements in a series of decreasing electronegativity. Since oxygen combined with everything and was liberated at the positive pole, it was obviously the most electronegative element, while potassium was the most electropositive. In compounds, the electrochemical nature of the element combined with oxygen determined the total polarity of the compound. This followed because the amounts of electricity in the two parts of an oxide seldom exactly neutralized each other. Therefore, when oxygen combined with an element, a compound of the “first order” resulted, such as potassium oxide, in which a positive charge remained, due to the strong electropositive character of the potassium. In the case of sulfuric acid (SO3, the anhydride) a negative charge predominated, for sulfur stood next to oxygen in the table of decreasing electronegativities. If now potassium oxide and sulfuric acid were brought together, potassium sulfate was formed, KO · SO3 as Berzelius would write it, since he doubled the atomic weight of potassium. This would be a compound of the second order. A charge could still remain, since the two parts would not exactly neutralize each other, and another charged salt such as aluminum sulfate could combine with the potassium sulfate to form alum, a third-order compound. Finally, to neutralize completely the various charges, water could be taken upto give the fourth-order compound, hydrated alum.
This theory involves several physical difficulties. Unipolarity, either in magnets or atoms, is not possible, and Berzelius confused quantity and intensity of electricity, a distinction which had been made by Faraday. Berzelius was not well trained in physics, and physicists in general did not pay much attention to his theory. Among chemists, however, it attracted many followers, since it explained so easily the behavior of inorganic substances and since the great authority of Berzelius gave it added weight. It can be seen that it contains many features that were later incorporated into the more modern theories of the structure of polar compounds. Until the discovery of organic compounds, which did not fit readily into the scheme, the dualistic theory dominated the thinking of almost all chemists.
Although the dualistic concept was the most influential of the theoretical syntheses of Berzelius, he drew together other scattered facts and gave generalized definitions of other chemical phenomena upon which much later chemistry developed. These generalizations were made in the course of his compilation of the annual reviews of the progress of chemistry which he published from 1821 until his death.
In the days following the Lavoisier revolution, chemical analyses and syntheses revealed a great variety of new compounds. It was generally assumed that each of these compounds must have an individual composition. Eventually, however, analytical results indicated that quite distinct compounds might have the same chemical composition. The most famous case was the identity in analytical results for the fulminates and cyanates as revealed by Liebig and Wöhler. Berzelius became interested in these strange results and collected a number of other cases in which the same phenomenon was observed. In 1831 he proposed the name isomerism for this phenomenon. The name was chosen by analogy with the term isomorphism used by Mitscherlich for different compounds with the same crystal structures. In 1840 Berzelius suggested the name allotropy for the existence of different forms of the same element.
An even more important generalization was made when Berzelius gathered together a rather large number of cases in which a reaction occurred only when some third substance was present, although this substance seemed to remain unchanged throughout the reaction. In 1835 he suggested that here a new force must exist whose nature was not clear to him. He suggested the name catalytic force and called decomposition of bodies by this force catalysis “as one designates the decomposition of bodies by chemical affinity analysis.”
Another term suggested by Berzelius was the word protein, which he proposed in a letter to Gerardus Mulder when the latter was investigating these compounds. He derived it from the Greek word proteios (“primitive”), since he recognized the prime importance of these compounds.
Berzelius was primarily interested in inorganic chemistry and most of his theoretical ideas were derived from the behavior of inorganic compounds. Nevertheless much of his early work involved analysis of animal products, and he continued to investigate organic compounds throughout most of his life. He developed a form of combustion apparatus which permitted him to analyze a number of carbon compounds, but which required a great amount of time. It took him eighteen months to carry out twenty-one analyses of seven organic acids. Liebig later developed this method to permit much more rapid determinations. However Berzelius was never as happy dealing with organic compounds as he was with inorganic salts. He considered organic chemistry not as the chemistry of carbon compounds, but as the chemistry of the living organism. To the day of his death he remained a vitalist. In the last edition of his textbook he said, “In living nature, the elements seem to obey entirely different laws than they do in the dead.” His attitude toward the rapidly developing field of organic chemistry became more and more antagonistic in the later years of his life. This fact emphasizes certain characteristics which were always important in his scientific outlook and which significantly determined the course of his work.
Berzelius was essentially a scientific conservative. His great experimental ability and his power to draw together diverse facts to produce important generalizations should not obscure the point that his work was based almost entirely upon the principles that he had learned in the first decade of his scientific activity. At that period chemical investigations were based very largely on the reactions of inorganic compounds, and this explains why Berzelius never really felt at home with organic chemistry. It involved new principles which were not his own. He resisted change when he felt his ideas were being violated. In the first part of his life he could gradually come to accept unpalatable conclusions. Thus, at first he refused to believe in the elementary nature of chlorine and nitrogen, believing them to be oxides of as yet undiscovered radicals. By 1818, however, he admitted that chlorine was an element, and by 1824 he came to the same conclusion for nitrogen.
As he grew older, it became more and more difficult to convince him that any change in his theories was possible. The mass of facts accumulated by the organic chemists alarmed him. Although at first he welcomed the radical theory expounded by Liebig and Wöhler from their investigation of the benzoyl radical, he soon realized that in this radical oxygen was present as a relatively unimportant constituent. This violated the dualistic theory. He tried to write formulas for radicals which could combine with oxygen as did metals or acids, and these formulas became more and more complicated as new facts contradicted them. Eventually all these formulas were rejected by his colleagues. The final blow came with the discovery by Dumas that chlorine could substitute for hydrogen in organic radicals without altering the essential properties of the compounds. Dumas and Laurent expanded the substitution principle into a major feature of organic chemistry. It was impossible for Berzelius to accept this, since for him negative chlorine could not replace positive hydrogen. His whole dualistic theory would collapse if he agreed to such a substitution.
Actually even the organic chemists recognized that they could not account for affinity in the compounds they studied. In developing their theory of types and later structural chemistry they simply represented chemical bonds by brackets or lines and made no attempt to explain what these represented. The relation of the forces holding salts together and those binding carbon to carbon or hydrogen could not be established until the electron theories of chemical bonding began to develop in the twentieth century. Then it was seen that there had been much truth in the Berzelius dualism, at least so far as polar compounds were concerned. This was of no help to Berzelius when he saw his precious theory discarded and his attempts to salvage it patronizingly disregarded by the new organic chemists. His attacks on Liebig, Dumas, and Laurent became more violent and much of the bitterness of his last years resulted from his inability to admit to any modification of the ideas he had developed in his most active years.
The tremendous influence which Berzelius exerted on the chemists of his time came not only from his experimental discoveries and his theoretical interpretations. His voluminous writings were translated into all important European languages and circulated everywhere in the chemical world. He reported his own discoveries in the various editions of his textbook, and he surveyed the whole progress of chemistry in his annual reports, the Arsberättelser över vetenskapernas framsteg, which were translated into German, mostly by Wöhler, and were read everywhere. Aside from these formal writings, Berzelius was personally acquainted with almost all the active chemists of Europe and after his visits to them he kept up an extensive correspondence, learning of new developments as they occurred and informing his friends about them even before he described them in his books. Much of his correspondence has been published.
In his own laboratory he worked directly with a succession of young Swedish and foreign students who thus learned his methods and thoughts firsthand and spread them abroad when they left him. Most of them maintained close friendship with him. In his autobiographical notes Berzelius lists twenty-four Swedes and twenty-one foreigners who worked in his laboratory. By the force of his personality, by the skill of his laboratory techniques, and by his power to collect, synthesize, and publicize the chemistry of his day, he exerted an influence on his own time which is still reflected in chemistry more than a century after his death.
I. Original Works. The publications of Berzelius were so numerous and appeared in so many editions, translations, and excerpts that a listing of even the major ones would consume a large amount of space. Fortunately a complete bibliography of all works by, and most works about, Berzelius has been compiled by Arne Holmberg, Bibliografi över Berzelius (Uppsala–Stockholm), Vol. I (1933), supp. i (1936), supp. 2 (1953); Vol. II (1936), supp. 1 (1953). A bibliography of the most important works is also given by J. R. Partington, A History of Chemistry, IV (London, 1964), 144–147. Berzelius’ own account of some of his work is found in Jöns Jacob Berzelius Autobiographical Notes, Olof Larsell, trans. (Baltimore, 1934).
II. Secondary Literature. The standard biography is H. G. Söderbaum, Jac. Berzelius, Levnadsteckning, 3 vols. (Uppsala, 1929–1931). A detailed account of the most important work is given in H. G. Söderbaum, Berzelius Werden und Wachsen 1779–1821 (Leipzig, 1899). Useful shorter biographies are Wilhelm Prandtl, Humphry Davy, Jöns Jacob Berzelius (Stuttgart, 1948) and J. Erik Jorpes, Jac. Berzelius, His Life and Work (Stockholm, 1966).
Henry M. Leicester
Berzelius, Jöns Jacob
BERZELIUS, JöNS JACOB
Väversunda, near Linköping, Sweden, 20 August 1779; d. Stockholm, 7 August 1848)
chemistry. For the original article on Berzelius see DSB, vol. 2.
A man of immense learning and energy, one of the most brilliant experimentalists of his century, and a creative and influential theorist, Berzelius was the dominating European figure in the science of chemistry during most of the first half of the nineteenth century. He was also a prominent authority in such cognate areas as geology, mineralogy, and physiology. Always sociable, witty, and amiable in private conversation, he could be blunt or even harsh in his letters and published critiques. But whatever his views, they always attracted attention and respect.
Literature on Berzelius prior to 1970. At the time of Henry Leicester’s DSB article on Berzelius, the literature on this illustrious scientist was sparse. There existed a detailed three-volume biography—Henrik Gustaf Söderbaum’s Jac. Berzelius Levnadsteckning(Uppsala, 1929– 1931)—but this work has never been translated from the Swedish, which has limited its impact. Söderbaum had earlier published a short version of part of this biography in German, titled Berzelius’ Werden und Wachsen, 1779–1821 (Leipzig: Barth, 1899). There existed a good short biography in English (Johan Erik Jorpes’s Jac. Berzelius, His Life and Work [Stockholm: Almqvist & Wiksell, 1966]), Berzelius’s own autobiography in Swedish and English, and a handful of more derivative biographies, obituaries, and articles in the secondary literature. There was also a good edition of much of Berzelius’s surviving correspondence, printed in original languages and edited by Söderbaum, Jac. Berzelius Bref, 6 vols. and supplements (Uppsala: Almqvist & Wiksell, 1912–1961), separate editions of his correspondence with Friedrich Wöhler and with Justus von Liebig in German, and a definitive bibliography edited by Arne Holmberg, Bibliografi över J. J. Berzelius, 5 vols. (Stockholm, 1933–1953). A generation after Leicester’s article, the literature on Berzelius is incomparably larger, and much has been learned in the intervening years.
Early Career. It is now understood that Berzelius was not quite the complete autodidact he has been portrayed (an image he himself wished to cultivate). Although his relations with the elderly phlogistonist professor Johan Afzelius were uneven at best, Berzelius’s studies at Uppsala benefited from the up-to-date teaching of Afzelius’s younger brother Pehr and of Johan’s capable assistant Anders Ekeberg. Swedish chemistry had suffered recent losses in the deaths of Torbern Bergman and Carl Scheele, but Ekeberg in particular had been influential in introducing Antoine-Laurent Lavoisier’s antiphlogistic chemistry to Sweden. From an early age Berzelius also avidly read the French, German, and English chemical literatures. He consorted with progressive circles at the university, imbibing many of the materialist, empiricist, rationalist, and utilitarian values typical of the late Enlightenment. These values coexisted comfortably with the liberal religious faith that he unreservedly shared with his Lutheran forebears, several of whom were pastors. His MD degree was awarded in May 1802, under the direction of Pehr Afzelius. In the same year, he was appointed unpaid assistant to the professor of medicine and pharmacy at the Stockholm School of Surgery while simultaneously serving as physician to the poor. Almost immediately he also began electrochemical experiments in collaboration with a wealthy friend, Wilhelm Hisinger, an investigation that resulted in a major discovery, that of a new element which Berzelius named cerium.
Influence and Writings. In 1807 Berzelius succeeded to the professorship of medicine and pharmacy. He spent his entire career in Stockholm rather than in the university city of Uppsala, teaching at the School of Surgery, renamed the Karolinska Institutet in 1810. This activity may have played a role in keeping his attention focused on the practical and empirical sides of chemistry, consistent with his inclinations. In the late 1820s Berzelius attempted to elevate his institution to official university status and fought for more utilitarian and modernist curricula across Sweden. He despised what he viewed as the metaphysical obfuscations of G. W. F. Hegel, Friedrich Schelling, and the Naturphilosophen. His was an increasingly influential voice: in 1810 he served a term as president of the Swedish Royal Academy of Sciences and in 1818 was elected its permanent secretary, a remunerative as well as an honorific post.
Berzelius’s influence abroad was promoted by his personal travels, by the few but highly select foreign students who spent time in his Stockholm laboratory, by his prolific publications, and by his massive private correspondence. His first visit abroad was to Great Britain, for four months in the late summer of 1812. In 1818–1819 he spent a year abroad, mostly in France although he visited Germany as well. Between 1822 and 1845 he made six more trips to Germany, which country became his principal foreign redoubt. His authority there was enormous, especially in the 1820s and 1830s, partly because of personal influence with such former students as C. G. Gmelin, Eilhard Mitscherlich, Heinrich and Gustav Rose, Gustav Magnus, and above all the great Göttingen chemist Friedrich Wöhler. In addition, he powerfully influenced Justus von Liebig, Robert Bunsen, Hermann Kolbe, and many others. Wöhler was the only one of these men whose regard for Berzelius extended so far as to master the Swedish language. For little financial reward, he translated thousands of pages of Berzelius’s massive textbook editions into German, and thousands of additional pages of Berzelius’s annual reports. Berzelius’s Lärbok i kemien (Textbook of chemistry) went through five German editions, four French editions, and editions in Spanish, Italian, and Dutch—though never in English. It was perhaps the last time that a single textbook author purported to treat the entire science in total detail. From portions of the second edition on (1825), each new authorized German edition came out simultaneously with the Swedish and can be regarded equally as editio princeps, due to Wöhler’s superb and prompt translations from the Swedish manuscript supplied by his older friend.
Starting in 1821, two months of every spring in Berzelius’s life was devoted to writing a detailed critical summary for the Swedish Royal Academy of chemical papers and books published during the preceding calendar year. These book-length Årsberättelser om vetenskapernas framsteg, or in Wöhler’s skilled translation the Jahresberichte über die Fortschritte der physischen Wissenschaften, immediately assumed enormous authority. Each year the book was anxiously awaited by European chemists, not only for the useful summaries of the international literature but for the sometimes sharply expressed judgments contained therein. In this manner Berzelius became known as the supreme authority in the science, whose favorable testimony could make a scientific career or whose severe criticism could lame one.
Initial Research. As a researcher, Berzelius’s earliest passion was physiological (“animal”) chemistry, and this was the subject of his first book (Föreläsningar i djurkemien, 2 vols., Stockholm, 1806–1808). This pioneering work, which has never been translated from the Swedish, summarized what was known on the subject, added much new empirical information, and proclaimed an essentially materialist philosophy of biology. Berzelius’s underlying program apparently was to demonstrate that materials derived from animals were not indeterminate generic mixtures but analyzable combinations of well-defined chemical substances. An adequate understanding of these fluids in this purely chemical sense would open the door, he thought, to rapid progress in the science of physiology, leading to knowledge that would have important new practical applications.
Chemical Atomic Theory. Berzelius retained a lifelong interest in physiological chemistry, but he was soon diverted into inorganic chemistry and mineralogy. This happened as the result of a careful literature review he conducted in 1807 in preparation for writing his general textbook of chemistry, the first volume of which was published in Swedish the following year. He encountered some of the early research on elemental combining proportions (stoichiometry), then early in 1809 learned secondhand about John Dalton’s atomic theory. He immediately understood the deep significance of chemical atomism and resolved to pursue the subject himself. In 1810 (in Swedish) and 1811–1812 (in German) he published a book-length stoichiometric study, reporting on, and experimentally repeating, essentially all of the determinations of elemental combining proportions in the literature. By the end of 1812 he had read Dalton in the original and had personally met with Humphry Davy and William Wollaston, both of whom were engaged with the same subject. Up until this time he had refrained from all theoretical interpretations of the emerging laws of stoichiometry. Now he began to offer a theory that, he said, was “analogous” to Dalton's, namely the “volume theory.” In this context he introduced an early version of the formula notational system still used today, in an installment of an English-language essay published in November 1813, in which Latin letters represent unit-combining “volumes” of elements (what Dalton had called “atoms”).
Berzelius’s influential development of the chemical atomic theory has been carefully studied by Evan Melhado, Anders Lundgren, Alan Rocke, and Ursula Klein, and these scholars’ approaches differ somewhat. Melhado portrays Berzelius as profoundly original, rather than a mere consolidator of earlier work, in that he successfully sought to understand the specific level of precisely characterized compounds rather than the generic level of property-bearing principles. Lundgren emphasizes Berzelius’s only partial acceptance of Dalton’s theory and characterizes his attitude toward atoms as more instrumental than realist, while Rocke argues that there was more in common between Berzelius and Dalton than may initially appear. Klein has demonstrated the extraordinary power of Berzelius’s formula notation, especially when it began to be used in an aggressively productive way from around 1830.
All these scholars recognize the enormous labor and thought that went into Berzelius’s final revision of atomic weights and molecular formulas, accomplished in 1826. Berzelius was almost unique at this time in his insistence on applying all possible approaches, physical as well as chemical, to the problem of the determination of weights and formulas, as well as creatively developing novel experiments, ingenious hypotheses, and useful conventions. Although it would be another generation before most European chemists agreed on a single system of atomic weights and molecular formulas, only minor modifications ultimately proved necessary to transform the Berzelian system of 1826 into that which provided the basis for modern chemistry.
Organic Chemistry. Berzelius’s profound influence extended also into organic chemistry, of which he must be considered one of the principal founders. From about 1811 he and Joseph-Louis Gay-Lussac semi-independently developed the combustion method of elemental organic analysis that was further improved by Liebig some few years later. In 1814 Berzelius published analyses of thirteen organic compounds, together with proposed atomistic formulas for their molecules, the first time this had ever been done for organic substances. As Melhado has argued, this development demonstrates again Berzelius’s strong interest in providing a means to get to the specific level of well-defined homogeneous chemical compounds, in this case for organic nature. Although it would be others who would develop organic chemistry further, led especially by Liebig and Jean-Baptiste Dumas, they did so on this Berzelian foundation.
For Berzelius, all molecules, organic as well as inorganic, were thought to be held together by the coulombic attraction of oppositely charged components (atoms or radicals). This “electrochemical-dualist” theory of chemical combination worked well in the inorganic and mineral realm but proved to be less satisfactory for organic compounds, because in such substances it was soon found that electrochemically dissimilar elements could substitute for each other indiscriminately. Berzelius’s heated opposition to substitutionist “type” theories during the last twenty years of his life has damaged his subsequent reputation, for those newer ideas led eventually to modern theories of atomic valence and molecular structure. John Brooke has argued persuasively, by contrast, that Berzelius’s opposition was neither unreasonable nor unproductive if one views the history in a more sympathetic, philosophical, and contextual fashion.
The Vitalism Issue. Berzelius has also sometimes been castigated for continuing the tradition of vitalist thought, which posited a special force that creates the properties of living creatures and which denies the possibility of artificial synthesis of organic compounds. In fact, recent historical research has suggested that Berzelius had a much more complex stance toward these issues. Many of his pronouncements, enunciated in his first book on animal chemistry and repeated occasionally throughout his life, suggest in fact that he had ardent materialist convictions and denied anything approaching a conventional vital force. But other statements, such as those in later editions of his textbook, appear to proclaim a pure and untroubled vitalist faith. There are in fact ways to understand how both of these convictions could coexist in Berzelius’s mind. His sincere religious faith made atheistic or reductionistic materialism repugnant, but his ardent commitment to Enlightenment values honored naturalism, empirical methods, and a materialist metaphysics. The result appears to have been a middle-ground position, which affirmed that there was indeed something unique in the circumstances of organic nature but that those circumstances were produced by the same scientific laws that reigned in the inorganic realm. These mysteries, Berzelius thought, may ever remain veiled to human understanding.
Berhhard, Carl Gustaf. Through France with Berzelius: LiveScholars and Dead Volcanoes. Oxford: Pergamon, 1985.
Brooke, John. Thinking about Matter: Studies in the History ofChemical Philosophy. Aldershot, U.K.: Ashgate, 1995.
Dunsch, Lothar. Jöns Jacob Berzelius. Leipzig, Germany: Teubner, 1986.
Klein, Ursula. Experiments, Models, Paper Tools: Cultures ofOrganic Chemistry in the Nineteenth Century. Stanford, CA: Stanford University Press, 2003.
Lundgren, Anders. Berzelius och den kemiska atomteorin [Berzelius and the chemical atomic theory]. Uppsala, Sweden: Almqvist & Wiksell, 1979.
Melhado, Evan M. Jacob Berzelius: The Emergence of HisChemical System. Madison: University of Wisconsin Press, 1981.
Melhado, Evan M., and Tore Frängsmyr, eds. EnlightenmentScience in the Romantic Era: The Chemistry of Berzelius and Its Cultural Setting. Cambridge, U.K., and New York: Cambridge University Press, 1992.
Rocke, Alan J. Chemical Atomism in the Nineteenth Century:From Dalton to Cannizzaro. Columbus: Ohio State University Press, 1984.
Alan J. Rocke
Jöns Jacob Berzelius
Jöns Jacob Berzelius
The Swedish chemist Jöns Jacob Berzelius (1779-1848) was one of the first European scientists to accept John Dalton's atomic theory and to recognize the need for a new system of chemical symbols. He was a dominant figure in chemical science.
Jöns Jacob Berzelius, the son of a clergyman-school-master, was born on Aug. 20, 1779, at Väversunda, Sweden. He studied for 6 years at the medical school at Uppsala and then studied chemistry at the Stockholm School of Surgery. In 1808 he was elected to the Swedish Academy of Science and was appointed its secretary in 1818. He married Elisabeth Poppius in 1835 and on that occasion was made a baron by the Swedish king, Charles XIV.
Atomic Weights and Chemical Symbols
During the first decade of the 19th century, chemists were becoming aware that chemicals combined in definite proportions. This concept, sometimes known as Proust's law after the French chemist Joseph Louis Proust, showed that no matter under what circumstances separate elements combined, their proportions would always be in whole-number ratios. Berzelius was the first to prove beyond a doubt the validity of Proust's law and having been impressed by Dalton's theory of atoms, he proceeded to determine atomic weights. By 1818 Berzelius had obtained, with a high degree of accuracy, the atomic weights of no fewer than 45 elements.
While engaged in this work, Berzelius came to the conclusion that the system of full names for the elements was a hindrance, and he also rejected Dalton's set of symbols for the elements. As a substitute (and this system became the international code for the elements), Berzelius suggested that the initial of the Latin name or the initial plus the second letter be used to designate the element. Now O could be written for oxygen, H for hydrogen, and CO for carbon monoxide. By adding subscriptive numbers, other compounds could be symbolized, such as CO2 for carbon dioxide and H2O for water. Thus a new international language of chemistry came into use.
Electricity and Chemistry
The numerous experiments on the effects of an electrical current on chemical solutions had caught the imagination of the scientific world quite early in the 19th century. The electrical current used was that obtained from one of Volta's "galvanic piles." Berzelius and Wilhelm Hisinger worked with the voltaic pile, and in 1803 they reported that, just as an electrical current could decompose water, it could separate solutions of salts so that the acids formed would go to one pole while the alkalies would be collected at the opposite one. In further experiments, with M. M. Pontin, Berzelius succeeded in producing amalgams of potassium, calcium, and ammonia, by using mercury as the negative electrode.
From these experiments in electrochemistry, Berzelius arrived at his own electrochemical theory, which stated that all compounds can be divided into their positive and negative parts. This so-called dualistic theory held that all compounds are divided into two groups: those that are electropositive and those that are electronegative. In any chemical reaction there is a neutralization of opposite electricities, and depending on the strength of the components, this reaction may vary from a very feeble one to ignition and combustion. The opposite of chemical combination, in Berzelius's view, was electrolysis, in which electric charges are restored and the combined molecular groups are separated.
In 1807, when he was appointed professor of medicine at the Stockholm School of Surgery, Berzelius began his researches in organic chemistry. At this time very little was known about organic chemistry, especially its involvement in life processes. Berzelius realized that he himself knew nothing of physiological chemistry. He thought that there might be some chemical process associated with the functions of the brain but admitted that the understanding of this seemed impossible. He began analyzing animal substances such as blood, bile, milk, membranes, bones, fat, flesh and its fluids, and animal semen. He discovered that blood contains iron and that muscular tissue contains lactic acid, the same acid found in sour milk. Most of his work in this field was inconclusive, as he was the first to realize. He concluded that analyses of animal products needed to await the day of more sophisticated techniques and apparatus, and he gave up his studies.
Discovery of New Elements
At an early point in his career, Berzelius became interested in a rare mineral, Bastnäs tungsten, and undertook an analysis of it. He came to the conclusion that it contained an unknown metal, and he and Hisinger named it cerium after the recently discovered asteroid Ceres.
Some years later Berzelius discovered the element selenium, which was isolated from the sediment in lead tanks used in the manufacture of sulfuric acid. He named his new discovery after the Greek word for the moon. His next discoveries, of the elements vanadium and thorium, were named after the Norse goddess Vanadium and the god Thor.
Berzelius's Textbook of Chemistry went through many editions and was translated into the principal European languages. To this work he added his tables of atomic weights. He devised new methods of analysis and obtained values for combining weights not very different from those found today. He started by using the atomic weight figure of 100 for oxygen and related all of the other elements to it.
Much of Berzelius's work involved studies of minerals. He found that previous systems of classification were unreliable, so he proceeded to devise his own system, based not on description of crystal forms but on chemical composition. In 1836 the Royal Society of London awarded him the Copley Medal for this work.
Of great importance to chemical knowledge in the 19th century were two concepts in theory, both of which are associated with Berzelius: isomerism and catalysis. He remembered that the lactic acid he had discovered in muscle tissue behaved differently toward polarized light than the lactic acid of fermentation. Other examples of such behavior could be found, and Berzelius suggested that compounds of the same chemical composition which possess different chemical properties be called isomers, from the Greek word meaning equal parts. The importance of understanding isomerism was that it demonstrates that there is more involved in chemical structure than the ratios of the elements and atomic weight. The manner in which atoms are distributed in a molecular structure is a determining factor in the chemical properties of a compound.
In 1835 Berzelius advanced the theoretical concept of catalysis, or chemical change in which one agent produces the reaction without itself being changed. Berzelius wrote about this process as it applied to plant chemistry. He believed that in inorganic chemical reactions metals can act as catalytic agents. In summing up catalysis, Berzelius wrote, "Thus it is certain that substances … have the property of exerting an effect… quite different from ordinary chemical affinity, in that they promote the conversion … without necessarily participating in the process with their own component parts…."
As secretary of the Swedish Academy of Science, and also for some years as librarian of the academy, Berzelius began in 1821 to publish the Annual Surveys of Progress in the Sciences. Publication was continued until his death, at which time 27 volumes had been issued. His massive correspondence with scientists has been published, and it is a comprehensive picture of the great chemical world which was unfolding in his day.
Personality and Character
It was perhaps natural that Berzelius, who achieved such great eminence early in the century, should have insisted on dominating the chemical sciences as they progressed. He was cheerful as a youth, but as he grew older and developed more and more health problems, he became conservative, argumentative, and even dictatorial. It has been said that when Berzelius condemned a new idea, it might just as well be forgotten, and that his insistence on the acceptance of his own ideas in part blocked the progress of chemistry. In his last years he was still denouncing some of his colleagues for what he termed their "Swedish laziness." He died on Aug. 7, 1848, and was buried in Stockholm.
The biography of Berzelius by J. Erik Jorpes, Jac. Berzelius: His Life and Work (1960; trans. 1971), is highly recommended. There is a long essay on Berzelius by Aaron J. Ihde, which contains many notes and references, in Eduard Farber, ed., Great Chemists (1961). Volume 4 of J. R. Partington, A History of Chemistry (1964), is also useful. On the subject of chemical nomenclature Maurice Crosland, Historical Studies in the Language of Chemistry (1962), should be consulted.
Melhado, Evan Marc, Jacob Berzelius, the emergence of his chemical system, Stockholm, Sweden: Almqvist & Wiksell International; Madison, Wis.: University of Wisconsin Press, 1981. □
Jöns Jacob Berzelius
Jöns Jacob Berzelius
The most renowned chemist of the first third of the nineteenth century, Jöns Jacob Berzelius excelled as a theorist, experimenter, teacher, designer of laboratory equipment, and disseminator of chemical information. He invented the modern system of chemical notation; named such chemical concepts as isomerism, isomorphism, allotropy, and catalysis; and discovered the chemical elements of cerium, selenium, and thorium.
Descended from three generations of Lutheran clergy, Berzelius lost his father at age two and his mother at age nine and was raised by relatives. He began medical studies in Uppsala in 1796 and completed them in 1802, thereafter making a meager living as a district doctor to the poor while working as an unpaid assistant to the professor of pharmacy at the School of Surgery in Stockholm. His fortunes improved upon succeeding to the professorship in 1807, which in 1810 was renamed a chair in chemistry.
Meanwhile, Berzelius had become friends with Wilhelm Hisinger, a prosperous mine owner. Together they undertook original researches using galvanic piles (the earliest batteries) to decompose numerous salts into their respective acidic and basic components, thereby greatly expanding the knowledge and techniques of inorganic analysis. Utilizing the newly formulated atomic theory of the British chemist John Dalton (1766-1844), Berzelius used these analytical results to establish both atomic weights and equivalent weights (the effective multiples of atomic weights for elements in chemical reactions) for more than two dozen elements, to previously unattained degrees of accuracy.
Extending Antoine Laurent Lavoisier's (1743-1794) previous systematic reform of chemical nomenclature for naming elements and compounds, Berzelius also simplified the existing unsystematic set of chemical symbols. He represented each element with the first letter of its Latin name and used a second significant letter when necessary to distinguish two or more elements with names having the same initial letter—e.g., C for Carbon, Ca for calcium, and Cu for copper (Latin "cuprum"). With minor alterations, this system is still in use today.
A triumphant visit to England in 1812 and meetings with its most eminent scientists secured Berzelius's international reputation. The year 1814 saw the first edition of his new classification of minerals according to chemical properties, which quickly replaced previous systems based on physical descriptions. In 1818-1819 he made a second trip abroad, to France, where he collaborated in research with leading chemists and completed a volume on chemical proportions in inorganic reactions. This formed a second part of what ultimately became the six-volume Textbook of Chemistry completed in 1830, which went through five editions and became a standard reference work.
While in France Berzelius was elected secretary of the Academy of Science in Stockholm, which doubled his salary and provided him with new laboratory facilities. In 1821 he founded an annual report on current chemical research throughout Europe, which he published each spring until his death in 1848. Generally known by its German title, the Jahresberichte, this became the single most important source of information for chemists of the era. In 1832 Berzelius resigned his other university obligations to concentrate on this work, and upon his belated marriage in 1835 was made a baronet.
Berzelius's most important theoretical contribution was his theory of electrochemical dualism. Classifying all elements as either electropositive or electronegative in character, he argued that all compounds resulted from combinations of these opposites and that a given element could substitute for another of the same electrical character in a compound. Initially this theory facilitated the explanation of a wide array of inorganic reactions, and aspects of it anticipated modern theories of polar bonding.
However, with the development of organic chemistry beginning in the 1830s, Berzelius's theory proved unable to explain how elements such as hydrogen and chlorine with supposedly opposite electrical characters could replace one another in organic compounds. Consequently the theory soon lost favor to the emerging rival substitution theories of chemical "types" and "radicals." Berzelius's reputation suffered as he refused to acknowledge the inadequacies of his system, used the Jahresberichte to violently attack his critics, and broke off long-standing friendships with Justus Liebig (1803-1873) and other chemists who opposed his views. However, his many lasting accomplishments and the work of his most prestigious students influenced chemistry for decades to come.
JAMES A. ALTENA