Meyer, Julius Lothar

views updated May 18 2018

MEYER, JULIUS LOTHAR

(b. Varel, Oldenburg, Germany, 19 August 1830; d. Tübingen, Germany, II April 1895)

chemistry.

(Julius) Lothar Meyer was the fourth of seven children of Heinrich Friedrich August Jacob Meyer, a prominent physician in Varel. His mother, the former Anna Sophie Wilhelmine Biermann, was the daughter of another physician of that town. Both Lothar and his brother, Oskar Emil, later a physicist, began their studies with the intention of entering medicine. Brought up as a Lutheran, Meyer first attended a private school, then the newly founded Bürgerschule in Varel, supplementing this education with private instruction in Latin and Greek. Delicate in his early years, he suffered such severe headaches at age fourteen that his father advised complete discontinuance of academic studies and placed him as an assistant to the chief gardener at the summer palace of the grand duke of Oldenburg, at Rastede. After a year his health was sufficiently restored for him to enter the Gymnasium at Oldenburg, from which he graduated in 1851. In the summer of that year Meyer began to study medicine at the University of Zurich, and in 1853 he moved to Würzburg, where Virchow was lecturing on pathology. He received the M.D. the following year. Encouraged by Carl Ludwig, his former physiology professor at Zurich, Meyer turned from medicine to physiological chemistry and went to Heidelberg to study under Bunsen. The latter’s work on gas analysis particularly attracted him, and in 1856 Meyer completed his investigation Ueber die Gase des Blutes, which was accepted by the Würzburg Faculty of Medicine as his doctoral dissertation. F. Beilstein, H. H. Landolt, H. E. Roscoe, A. von Baeyer, and F. A. Kekulé were in Heidelberg at the same time. Lectures by Kirchhoff moved Meyer further toward physical chemistry.

At the suggestion of his brother, Meyer moved to Königsberg in the fall of 1856, to attend Franz Neumann’s lectures on mathematical physics. He also pursued there his earlier physiological interests by studying the effect of carbon monoxide on the blood. When he moved to Breslau in 1858, this investigation was accepted by the Philosophy Faculty as his dissertation for the Ph.D. In February 1859 Meyer established himself as Privatdozent in physics and chemistry at Breslau with a critical historical work, “Ü die chemischen Lehren von Berthollet und Berzelius.” That same spring he took over the direction of the chemical laboratory in the physiological institute and lectured on organic, inorganic, physiological, and biological chemistry. During his stay at Breslau the first edition of his Die modernen Theorien der Chemie umi ihre Bedeutung für die chemische Statik appeared (1864). It went through five editions and was translated into English, French, and Russian.

Meyer had attended the 1860 Karlsruhe Congress, where he heard Cannizzaro and read his paper on the use of Avogadro’s hypothesis and the law of Dulong and Petit in establishing atomic weights and formulas. Meyer edited Cannizzaro’s paper for Oslwald’s Klassiker der Exacten Wissenschaften and describes in that work how “the scales fell from my eyes and my doubts disappeared and were replaced by a feeling of quiet certainty.” Meyer’s Moderne Theorien was a direct outcome of that experience. In a brief obituary in 1895 the book was described as “not especially well received at first, but as years passed it exerted a more and more powerful influence on the thoughts of chemists. From a flimsy pamphlet it grew to a stalely volume, and it has generally been recognized as the best presentation of the fundamental principles of chemistry until the physicochemical movement began,”¹

Meyer was called to the School of Forestry at Neustadt-Eberswalde in 1866 for his first independent position. The same year he married Johanna Volkmann; they had four children. In 1868 Meyer succeeded C. Weltzien as professor of chemistry and director of the chemical laboratories at the Karlsruhe Polytechnic Institute. His final move, in 1876, was to Tübingen, where he taught until his death.

Two major events occurred in the early years of Meyer’s stay at Karlsruhe. Mendeleev’s 1869 paper on the periodic table led him to submit his own matured ideas for publication in December of that year. The paper was published in March 1870. In the summer of 1870 the Franco-Prussian War broke out; and Meyer made use of his medical abilities, helping to organize an emergency hospital in the buildings of the Polytechnic.

Meyer’s Tübingen years at last offered an opportunity for intensive pursuit of his major interests. In excellent health until his sudden death, he guided the work of over sixty doctoral candidates; and with his associate Karl Seubert he published a careful analysis of the best atomic weight determinations available until then. In 1890 Meyer published Grundzüge der theoretischen Chemie, a less technical account of the theoretical foundations of chemistry than the later editions of his Moderne Theorien had become.

Outside his work in chemistry, Meyer read Greek and Latin classics and retained his love for gardening, learned in his youth. He was concerned with higher education and gave a number of lectures-later published—on that subject. For the year 1894–1895 he was elected rector of Tübingen University.

Meyer received the Davy Medal of the Royal Society jointly with Mendeleev in 1882. In 1883 he became a foreign honorary member of the Chemical Society (London) and in 1888 and 1891 corresponding member of the Prussian and St. Petersburg Academies of Sciences, respectively. He was given a title of nobility by decree of the Württemberg crown in 1892.

Meyer’s earliest research dealt with physiological aspects of the uptake of gases by the blood. Building on previous studies by G. Magnus, he was able to demonstrate in 1856 that oxygen absorption by blood in the lungs occurs independently of pressure. This suggested to him that some possibly loose chemical linkage occurred. When he turned his attention to carbon monoxide poisoning, Meyer demonstrated a similar chemical linkage between that gas and a constituent of the blood. Further, he found that the amounts of oxygen and carbon monoxide taken up by the blood were in a simple molecular ratio, the carbon monoxide being able to expel volume for volume the oxygen already in the blood. This suggested to him that the same constituent of blood reacted with both gases. His preliminary searches for this constituent were unsuccessful. Hemoglobin was discovered by Hoppe-Seyler in 1864.²

Although these physiological studies were of considerable importance, Meyer’s greatest achievement is no doubt tied to his work on the periodic classification of the elements. Meyer and Mendeleev both received their major stimulus for these considerations at the 1860 Karlsruhe Congress through Cannizzaro’s paper on atomic weights. By 1862, Meyer had completed the manuscript of Moderne Theorien, including a table of twenty-eight elements in order of increasing atomic weight. Meyer felt that by the early 1860’s considerable unity had finally been achieved regarding the fundamental principles of chemistry; and it was the purpose of his book to present these theoretical foundations.

Meyer saw J. W. Döbereiner and M. von Pettenkofer as his direct precursors and later edited their key papers. In 1816–1817, and more fully in 1829, Döbereiner had drawn attention to the fact that similar chemical elements often occurred in groups of three and that the arithmetic mean of the atomic weights of the lightest and heaviest elements often corresponded closely to the atomic weight of the third member of the group. His “triads” included calcium, strontium, and barium; lithium, sodium, and potassium; chlorine, bromine, and iodine; sulfur, selenium, and tellurium. Such a quantitative relationship suggested to some the likelihood that atoms were not the ultimate building blocks of nature—that they were composite, with the differences in weight of successive members of triads representing weights of more fundamental units.

Pettenkofer, pursuing Döbereiner’s ideas, pointed to the parallelism between regular increases in equivalent weights of similar elements and increases in molecular weights of successive members of homologous series in organic chemistry.³ Thus CH₃=15, C₂H₅=29, C₃H₇=43, C₄H₉=57, C₅H₁₁=71. The common increment (of 14) in these weights suggested that organic radicals may well hold the clue to the nature of the internal structure of inorganic atoms. Similar ideas were independently developed by Dumas, who spoke about them to the British Association for the Advancement of Science in 1851 but did not publish them until 1857.⁴ Further attempts at systematizing the elements known to Meyer were made by J. H. Gladstone (1853), J. P. Cooke (1854), W. Odling (1857), and E. Lenssen (1857).

No progress beyond the arithmetic comparisons of weights of similar elements was likely as long as no clear distinction was made between equivalent and atomic weights, and no path to the values of the latter was generally accepted. That clarification was achieved by Cannizzaro at Karlsruhe in 1860, and almost immediately further relations between the elements became apparent. In 1862 A. E. Béguyer de Chancourtois plotted atomic weights of elements on a “telluric screw,” on which similar elements would fall directly below each other. J. A. R. Newlands, beginning in 1863, organized the elements by their atomic weights, as computed by Cannizzaro’s methods, into ten families (later reduced to eight). In an early table blanks were left for undiscovered elements; but these later disappeared in the eightfamily version of 1865, which New lands claimed as illustrating a “law of octaves.”

Near the end of the first edition of Meyer’s Moderne Theorien, the author points to the evidences for the composite nature of atoms, emphasizing the parallelism between series of related elements and organic compounds. He then appends a tabulation (see Figure 1) of twenty-eight elements, arranged according to increasing atomic weight, in six families that have valences of 4, 3, 2, 1, 1, and 2, respectively. Thus the integral stepwise change in valence as atomic weight increases was in print by 1864. A relation between families, and hence between dissimilar yet neighboring elements, was clearly established. Meyer remained interested also in constant increments within families and left a space for an as yet undiscovered element between silicon and tin, clearly indicating its probable atomic weight to be 28.5+44.55, or 73.1. His next publication on the subject appeared after Mendeleev’s historic 1869 paper, which Meyer had seen only in its abbreviated German form.⁵

Meyer’s independent establishment of the central principles underlying the periodic table of the elements was demonstrated in 1893, when Adolf Remelé, his successor at Neustadt-Eberswalde, showed him a handwritten draft periodic table (Figure 2) designed by Meyer for the second edition of Moderne Theorien and given to Remelé in July 1868. Its notation “§91” makes clear its intended use for the second edition. It differs from the 1864 table mainly by the addition of twenty-four elements and nine families. These were the B-subgroups, the characteristics of which Meyer later claimed to have discovered independently. Hydrogen, boron, and indium are not in the table, and aluminum appears in both column 3

and column 4. Boron, indium, and aluminum properly belong in a family between columns 7 and 8. Meyer placed lead (Pb) correctly in column 8, while Mendeleev put it with calcium, strontium, and barium. Remelé’s disclosure was published by Seubert after Meyer’s death.⁶

In Meyer’s classic paper of 1870, he adopted Mendeleev’s use of a vertical form for the periodic table, publishing a table (Figure 3) in which the relation of the A- and B-subgroups of the chemical families is for the first time clearly indicated.⁷ He also attached his graphical representation of the variation of atomic volume of the solid elements (volume divided by atomic weight) when plotted against atomic weight (Figure 4), for which he is most generally known. Both Meyer and Mendeleev emphasized that there is a periodic variation, a succession of maxima and minima, in several physical and chemical properties when they are examined as functions of atomic weight. Meyer began this paper with the assertion that it is most improbable that the chemical elements are absolutely undecomposable and referred to the ideas of Prout, Pettenkofer, and Dumas. As for the gaps in the table, he suggested that they would be filled through careful redeterminations of the atomic weights of known elements or through the discovery of new ones.

The significance of atomic weights in the demonstration of chemical periodicity, and the suspicion that some atomic weights were not accurate, led Meyer and Seubert to examine critically and to recalculate all atomic weights then considered important. Their study was published in 1883. All atomic weights were referred to the standard of unity for the atomic weight of hydrogen, a standard Meyer championed. Wilhelm Ostwald, on the other hand, strongly urged the adoption of O = 16,000 as standard, a view accepted in 1898 by a special committee of the German Chemical Society consisting of Landolt, Ostwald, and Seubert. In 1903 the newly created International

Difference form I to II and from II to III about =16.

Difference form III to V Iv to VI, V to VII fluctuating around 46.

Difference form VI to VIII, from VII to IX =88 to 92.

Commission on Atomic Weights decided to publish parallel tables based on H = 1 and O = 16, a practice followed for many years, The arguments for the oxygen standard were that the O:H ratio was for many years in doubt and that far more elements formed stable compounds with oxygen than with hydrogen.

In organic structural theory Meyer became involved in discussions of the structure of benzene. In 1865 Kekulé had proposed ring formula I; but ihis predicted two substances C₆ H₄ X₂, each having the two suhstituents, X, on adjacent carbons (II and III). Only one

was ever found, and in 1872 Kekulé proposed a complex atomic oscillation mechanism in order to make all carbon atoms equivalent.⁸ In the same year, in the second edition of Moderne Theorien, Meyer proposed a much simpler solution. He suggested that each carbon used only three of its four affinities, leaving one valence unsatisfied. His formula was the first of a series of “centric” formulas proposed by a number of chemists. The unused valences point to the center of the ring.

Meyer studied a number of benzene substitution reactions, particularly the nitration of benzene and its derivatives. He examined the effects of time, temperature, solvent, and concentration of reagents, feeling that chemists must go beyond a mere interest in the nature and quantity of products and must subject chemical reactions themselves to quantitative study. He examined reagents that facilitated chlorination and oxidation, the so-called chlorine and oxygen carriers, thus laying some of the groundwork for Ostwald’s extensive revision of the concept of catalysis (1894). Meyer’s studies of the effects of reagent concentration on chemical reactions served to confirm the law of mass action enunciated by C. M Goldberg and P. Waage. In the fourth edition of Modcrne Theorien (1883), he included a major new section, constituting more than a third of the book, entitled “Dynamik der Atome.”

Meyer and his students investigated a number of physical properties, such as the boiling points, of structurally related organic compounds, seeking relations between these properties and molecular structure. His wide-ranging interests and mechanical skill led Meyer to devise or improve many pieces of apparatus, often adopted by other chemists. He pleaded with chemists to systematize inorganic chemistry on the basis of the periodic table, in order to approach the organization of subject matter achieved in organic chemistry.

NOTES

1. I. R., “Lothar Meyer,” in Journal of the American Chemical Society, 17 (1895), 471–472,

2. F. Hoppe-Seyler, “Ueber die optischen und chemischen Eigenschaften des Blutfarbstoffs,” in Virchows Archiv fér pathologische Anatomic und Physiologie und fér klinische Medizin, 29 (1864), 233–235,

3. M. Pettenkofer, “Ueber die regelmässigen Abstände der Acquivulcmzahlen der sogemmnten einfaehen Radicalen,” in Müchener Gelehrten Anzeigen, 30 (1850), 261–272: repr. with new intro. by the author in Atmalen der Chemie, 105 (1858), 187–202,

4. J. B. A. Dumas, “Memoire stir les équivalents des corps simples,” in Comptes rendus … de I’ Académie des sciences, 45 (1857), 709–731; 46 (1858), 951–953; 47 (1858), 1026–1034.

5. D. Mendeleev, “Sootnoshenie svoistv s atomnym vesom elementov” (“The Correlation Between the Properties and the Atomic Weights of the Elements”), in Zhurnal Russkago fiziko-khimicheskago obshchestva pri Imperatorskago St-Peterhurgskago universitete, 1 (1869), 60–77; Zeitschrift fér Chemie,12 (1869), 405–406.

6. K. Seubert, “Zur Geschiehte des periodischen Systems,” in Zeitschrift für anorganische… Chemie, 9 (1895), 334–338.

7. L. Meyer, “Die Natur der chemischen Elemente als Function ihrer Atomgewichte,” in Justus Liebigs Annalen der Chemie, supp. 7 (1870), 354–364.

8. F. A, Kekulé, “Ueber einige Condensationsproducte des Aldehyds,” in Annalen der Chemie, 162 (1872), 77–124.

BIBLIOGRAPHY

I. Original Works. Meyer’s publications and those of students under his direction are listed in the extensive obituaries by K. Seubert, in Berkhte der Deutschen chemischen Gesellschaft,28R (1895), 1109-1146; and P. P. Bedson, in Journal of the Chemical Society, 69 (1896), 1402–1439, repr. in Memorial Lectures Delivered Before the Chemical Society, 1893–1900 (London, 1901). Bedson’s bibliography is copied from Seubert’s, Unfortunately the listing of doctoral publications is given under the year of the dissertation and not the year of publication of the journal article. The volume of each journal article is, however, given. The bibliography includes, in addition to Meyer’s technical articles, a number of his obituaries and more general lectures and papers, particularly on education and the nature of the university.

Meyer’s major work is Die modernen Theorien der Chemie und ihre Bedeutung fér die chemische Statik (Breslau, 1864, 1872, 1876, 1883, 1884). The 1st ed, was translated into Russian as Novieishie teorii khimii ikh znacherie dlya khimicheskoy statiki (St. Petersburg, 1866). The 5th ed, was translated into English by P. Phillips Bedson and W. Carleton Williams, Modern Theories of Chemistry (London, 1888), and French by A. Bloch and J. Meunicr, Les théoriés modernes de la chimie et leur application a la mécamique chimique, 2 vols. (Paris, 1887–1889). His less technical account of the same subject appeared as Grundzüge der theoretischen Chemie (Leipzig, 1890; 2nd ed., 1893); there is an English trans. by R Phillips Bedson and W. C. Williams, Outlines of Theoretical Chemistry (London, 1892).

Lothar Meyer and Karl Seubert published Die Atomgewichte der Elemente a us den Originalzahlen neu berechnet (Leipzig, 1883).

Meyer edited two works in Ostwald’s Klassiker der Exacten Wissenschaften: no. 30, Abriss eines Lehrganges der theoretischen Chemie, vorgeiragen von Prof S. Cannizzaro (Leipzig, 1891); and no, 66, Die Anfänge des natür lichen Systemes der chemischen Elemente. Abhandlungen von J. W. Döbereiner und Max Pettenkofer (Leipzig, 1895), which contains a historical survey by Meyer of the further development of the doctrine of the triads of the elements. Meyer’s major contributions on the periodic law (1864, 1870) were published with those of Mendeleev in Ostwald’s Klassiker, no. 68, edited with commentary by Karl Seubert: Das natürliche System der chemischen Elemente, Abhandlungen von L. Meyer und D, Mendeleeff (Leipzig, 1895).

The paper that established Meyer as codiscoverer of the periodic law is “Die Natur der chemischen Elemente als Function ihrer Atomgewichte,” in Justus Liebigs Annalen der Chemie, supp. 7 (1870), 354–364.

II. Secondary Literature. In addition to the major obituaries by Seubert and Bedson (see above), there is P. Walden, “Meyer, MendelejelT, Ramsay, und das pcriodische System der Elemente,” in G. Bugge, ed., Das Bach der grossen Chemiker, ti (Berlin, 1930), 229–287, with further bibliographic sources on p. 508. Brief biographical sketches were written by J. H. Long, in Journal of the American Chemical Society, 17 (1895), 664–666; and R. Winderlich, in Journal of Chemical Education, 27 (1950), 365–368,

Meyer’s work and its context are discussed in some detail in P. Venable, The Development of the Periodic Law (Easton, Pa., 1896), 96–108; and in Ida Freund, The Study of Chemical Composition (Cambridge, 1904; repr. New York, 1968), esp. ch. 16.

The question of Mendeleev’s priority in enunciating the periodic law was discussed under the title “Zur Geschichte der periodischen Atomistik” by L. Meyer, in Berichte der Deutschen chemischen Gesetlschaft, 13 (1880), 259–265, 2043–2044; by D. Mendeleev, ibid., 1796–1804; and K. Seubert, in Zeitschrift für anorganische… Chemie, 9 (1895), 334–338. See also J. W. van Spronsen, “The Priority Conflict Between Mendeleev and Meyer,” in Journal of Chemical Education, 46 (1969), 136–139; J. W. van Spronsen, The Periodic System of Chemical Elements: A History of the First Hundred Years (Amsterdam-London-New York, 1969), 124–132; and H. Casscbaum and G.B.Kauffman, The Periodic System of the Chemical Elements: The Search for Its Discoverer,” in Isis. 62 (1971), 314–327.

Otto Theodor Benfey

Complete Dictionary of Scientific Biography

Meyer, Lothar

views updated May 09 2018

Meyer, Lothar

GERMAN CHEMIST 1830–1895

Lothar Meyer was the son and grandson of physicians, so it was only natural that initially he decided on a career as a physician. At the age of twenty-one, he began his studies in medicine at the University of Zurich and received his M.D. in 1854. By then Meyer had become interested in the chemistry of the body and went on to study under Robert Bunsen at Heidelberg, where he learned how to analyze gases. He used these techniques to study the absorption of oxygen and carbon monoxide by the blood, and was able to establish that they both reacted in a similar fashion with the same constituent present in the blood. Meyer also determined that carbon monoxide was able to displace oxygen from the blood. However, he was unable to identify the particular component in the blood responsible for binding. This substance was identified as hemoglobin eight years later by Felix Hoppe-Seyler, a professor of physiological chemistry at the University of Strasbourg in France. For this work, Meyer received his Ph.D. in 1858 at the University of Breslau, and he became the director of the chemical laboratory in the physiology institute there until 1866.

In 1864 Meyer published Modern Theories of Chemistry, which went through five editions and was translated into English, French, and Russian. This book contained a prototype of his 1870 Periodic Table, which consisted of only twenty-eight elements arranged in six families that had similar chemical and physical characteristics. Above all he used a number referred to as the combining power of each element, later termed the valence , to link together a particular family. For example, carbon, silicon, tin, and lead were assigned to the same family because each exhibited a combining power of four. He also recognized the following from the observation that atomic weights usually increase by a certain amount between family members: A missing element existed between silicon and tin (later this gap was filled by germanium, discovered in 1886 by the German chemist Clemens Winkler). By 1868 he had expanded his table to include fifty-three elements, but this version was not made public until 1895. This was unfortunate because in 1869 the Russian chemist Dimitri Mendeleev published his version of the Periodic Table in a paper entitled, "The Relation of the Properties to the Atomic Weights of the Elements." As well as postulating his table, Mendeleev described how it could be used to predict not only the atomic weight of missing elements, but also their actual properties.

The most famous of Mendeleev's predictions involved eka-boron (scandium), eka-aluminium (gallium), and eka-silicon (germanium). For example, for eka-silicon he predicted its atomic weight, its density, the compounds it would form, and details about their physical properties. When thirteen years later germanium was discovered and it was determined that Mendeleev's predictions had been correct, scientists began to recognize the importance of the Periodic Table, and its discovery was quite naturally associated with Mendeleev, who encouraged this association.

Even in the twenty-first century, although historians recognize that others, especially Meyer, should be given considerable credit for the discovery of the periodic properties of the elements, most textbooks credit only Mendeleev.

see also Bunsen, Robert; Mendeleev, Dimitri; Periodic Table.

John E. Bloor