Dmitry Mendeleyev not only took an active part in the work as a teacher of mathematics and physics and later of other natural sciences, but he also continued his research. The work generally named “Specific Volumes” was the logical continuation of studying isomorphism. This work was a many-sided research, which is possible to be considered as a peculiar scientific trilogy, devoted to the pressing questions of chemistry of the middle of the 19th century. The scientist addressed to the deeper study of the substance structure, to the problem of the atom and molecule volume. The work appeared to be not only deserving the presentation as a dissertation for the Master’s degree, but right away it became the foundation of the second dissertation “for the right to deliver lectures.” After having come back to Petersburg from Odessa, the young scientist got an opportunity to stay in the capital and to get the post of professor’s substitute at the University.
In 1859 D. Mendeleyev got a permission for a foreign trip “to improve in the sciences.” He went abroad with a properly worked out original programm of the research. The theoretical idea of the close connection between the physical and chemical characteristics of the substance became its foundation. During this period Mendeleyev especially emphasized the research of the cohesion of the particles. He supposed to study them by measuring the surface tension of the liquids (the phenomenon of capillarity) at the different temperatures.
Dmitry Ivanovich wrote, “Being sent oversea in 1859, I studied only the capillarity, supposing to find there the clue to the solution of many physico-mathematical problems”; “… I intended to determine the interdependence between the particle volume and the cohesion”; “The measure of the solid cohesion, undoubtly, is an attribute more intrinsic than i. e. the boiling-point, and until now we have very few data about it.”
Dmitry Mendeleyev left Petersburg without having any clear idea of a science center of Europe where he was going to work. In a month spent on travelling around different cities, he chose Heidelberg, in the well-known university of which worked R. Bunsen, G. Kirchhoff, E. Erlenmeyer and other prominent scientists.
Having settled down in Heidelberg, Mendeleyev right away decided to establish his own laboratory, since it was impossible to carry out such “delicate experiments as capillary ones” in the laboratory, offered him by R. Bunsen. While starting to work the scientist gave a great consideration to the acquirement of good measuring instruments and their thorough study. While working in Heidelberg, studying the interdependence of the particle volume and the cohesion and studying the capillarity, D. Mendeleyev worked out the system of metrology and created the unique measuring equipment. For instance, he developed a fundamentally new instrument for the determination of the liquid density, which was later named after him, – densimeter of D. I. Mendeleyev.
Concerning the series of works of the 1850–1860’s, connected with the research of liquids, Mendeleyev told about it at the end of his life: “Being partly disappointed, I had absolutely given up this difficult subject, where, however, I was thinking independently. It is evident because I discovered the «absolute boiling-point»”. He succeeded to determine that liquid had turned to steam under a certain temperature, which was called by him the absolute boiling-point.
This discovery is the first important scientific achievement of Mendeleyev. Later, after the works of T. Andrews, another term firmed up in the science – “critical temperature.” However, Mendeleyev’s priority in the ascertainment of this significant phenomenon is nowadays undoubted and generally acknowledged.
Mendeleyev’s works on the subject of capillarity, realized by him in Heidelberg, are the logical continuation of his previous research. After having analyzed the whole of the scientist’s works and plans at the end of the 1850’s, it is possible to say that he longed for constructing the general system of physico-mathematical knowledge. Obviously, as a result of his research of the specific volumes the scientist made sure that knowledge about the atom size and the positional relationship of the particles wasn’t enough for the complete explanation of chemical characteristics of substances. He came to a conclusion that they should be supplemented with the characteristics, which were defining the force of interaction of the particles. Mendeleyev tried to work out the main regulations of a special theoretical discipline – molecular mechanics, which rests upon the three values: weight, volume and the force of interaction of the particles (molecules).
Maria Dmitrievna Mendeleyeva (nee Kornilyeva; 1793–1850), the mother of D. I. Mendeleyev. Unknown painter. Oil painting
Ivan Ivanovich Mendeleyev (1783–1847), the father of D. I. Mendeleyev. Unknown painter. Oil painting
The building of Tobolskaya gymnasium, where D. I. Mendeleyev was studying in 1841-1849
Gymnasium attached to the lycee de Richelieu in Odessa, where D. I. Mendeleyev was teaching in 1855-1856
The attempt to construct the molecular mechanics is very interesting. It is an example of the orientation of the scientist’s works to the significant theoretical generalizations. Though today this idea is only of a historical importance, nevertheless, it describes perfectly the independent approach of the scientist to the solution of the problems of the substance structure. In the middle of the 19
century it hadn’t been generally acknowledged yet and it had been supported only by individual scientists in different countries. The molecular theory started to be generally acknowledged only after the International chemical congress in Carlsruhe in 1860.
Participation in the International chemical congress, which took place on September, 3
-5
of 1860, became for Mendeleyev one of the most bright events of that year, which influenced greatly upon his choice of scientific interests during the following years. Mendeleyev came to the congress as a member of the delegation of Russian chemists, where were N. N. Zinin, A. P. Borodin, L. P. Shishkov, etc. During the congress’s work Dmitry Mendeleyev got acquainted with many prominent scientists of Europe. Those were J.– B. Dumas, Ch. Wurza and S. Cannizzaro, G. Rosko, etc. He continued communicating with them later.
It is difficult to overestimate the meaning of the International chemical congress in the history of chemistry. There was accepted the common system of atomic weights and were defined the conceptions of the molecule and atom.
As stated above, the scientific conceptions, which had been generally acknowledged at the congress of 1860, appeared in Mendeleyev’s research even before; the fundamentals of the molecular theory, as well as the principles of defining the molecular weight and density, were delivered by him at his lectures.
At the beginning of the 1860’s another important event took place in the life of D. I. Mendeleyev. On April, 29
of 1862 there was a wedding of Dmitry Mendeleyev and Theozva Nikitichna Leshchova, the stepdaughter of Pyotr Petrovich Ershov, the authour of the fairy-tale “Konyok-Gorbunok” (“The gibbous horse”). The wife was six years older than her husband. Their first-born son was Volodya, then daughter Olga was born. But this marriage wasn’t a happy one. Active work of a scientist, his uneasy way of life appeared to be far from the supposed ideal of wife. Interests and characters of this married couple were too different. At the beginning of the 1870’s their relationships started being complicated. Theozva Nikitichna gave her husband absolute freedom under the condition that the official marriage wouldn’t have been annulled.
In spite of the difficult relationships with his wife, D. I. Mendeleyev always behaved towards the family very carefully and responsibly. Especially he loved children, he often said, “Whatever I do and, however, I’m busy, I’m always happy when any of them comes to me.” The only thing, which could interrupt his work, were the children. If he suddenly heard the children’s screaming or crying, right away he rushed to find out what had happened. He used to come running and frightened, screamed loudly and threateningly, but in no circumstances at the child, but at the nunny. The nunny experienced it almost always and the children – never. Dmitry Ivanovich said, “I experienced many things in my life, but I don’t know the better happiness than to see my children next to me.”
His niece Nadezhda Yakovlevna Kapustina-Gubkina remembered that he loved and worried not only about his own children. In Boblovo – the estate purchased by D. I. Mendeleyev in 1865 on an equal footing with his friend N. P. Ilyin – in summer there were having rest several families with their children. The kids were always around the master of the house, they used to walk with him on his household business. It was interesting for them to listen to the stories of Dmitry Ivanovich, to walk with him about the forest, to share with him their joys and sorrows.
N. Y. Kapustina-Gubkina remembered an episode, which had vividly illustrated Dmitry Ivanovich’s delicacy towards the child’s soul, his kindness, “In the morning my elder brother and sister were teaching us in Russian and in French. I perplexed in my translation and my sister was keeping me for a long time under the lesson. Dmitry Ivanovich was passing by the sitting-room, where we were studying, and told my sister casually:
– Why are you exhausting her over the book, Anyuta? Let her walk, she will have time.
Right away I ran away, but after forty years I remember how kind he was towards the child’s soul.”
D.В I. Mendeleyev is a scientist, a teacher, a public figure
The 1860’s became for Dmitry Ivanovich Mendeleyev the time of realization of the significant research of scientific and applied nature. Here the amazing correlation of theoretical works of the scientist and their practical application became apparent.
Later his son Ivan Dmitrievich Mendeleyev wrote about his father, “I knew as though two Mendeleyevs. One of them was an assiduous collector of facts, a petty empiricist – Wagner of Goethe, for whom the highest pleasure was the treatment of the number, piling of the data, examination of interesting individual features of the phenomena. Another one was the valorous Faust, passing away to the “spirits’ world”, to the world of ideas, to the world of general laws…”
In 1861, at the suggestion of the “Public Good” Publishing House, D. I. Mendeleyev wrote a manual of organic chemistry, which became the first Russian textbook on this subject. The basis of this manual was the series of lectures delivered by him in 1857–1858. The book was written during the extremely short term and it caused the broad response in the scientific and public groups. Mendeleyev was awarded to a prize of the Academy of Sciences, and in 1863 the second edition of the manual was published.
Mendeleyev also started to edit the Technical Encyclopedia in many volumes “Technologies according to Wagner” (Wagner J.– R. Theorie und Praxis der Gewerbe: Hand und Lehrhuch der Technologie). Wagner’s Encyclopedia was published in Leipzig in 1857–1860 and had a great success in Europe. First, D. I. Mendeleyev decided to make a translation only because of the lack of money. He remembered, “I started translating and completing the “Technologies according to Wagner” because it was paid (30 rubles per sheet), but then I was interested and made many additions…”
The work on editing this book took several years. Dmitry Ivanovich not just translated the “Technologies…” from German, but he made a large amount of adjustments, sometimes completing the book with his own chapters. After all, the “Technologies according to Wagner” played a significant role in the choice of the future subject of the scientist’s research. In the third part of the “Technologies…” there were discussed the scientific and technological problems, connected with alcohol production. The practical importance of precise data about the density of alcohol-aqueous solutions and theoretical meaning of these data combined in this question. Density had been always considered by D. I. Mendeleyev as the most important parameter of substance. By the middle of the 1860’s the scientist started paying less attention to the edition of the “Technologies according to Wagner” and was more and more concentrated on the research of the alcohol-aqueous solutions.
In 1863, in connection with the development of the technology of alcohol-aqueous industry, Mendeleyev started a new big series of science works on this subject. On the first stage he was constructing the instruments for defining alcohol concentration – alcoholometers. And on the next stage – the thorough research of relative density of alcohol-aqueous solutions in the whole interval of concentrations under several temperatures. This experimental work became the foundation of the Doctoral thesis, which was presented by him to the Council of Petersburg University at the end of 1864 and was defended by him in 1865.
The research “About the connection of alcohol with water” contains the basic regulations of Mendeleyev’s doctrine of the solutions and it especially determines the existence of water and alcohol connections. Here are the results of measuring the density of aqueous solutions of ethyl alcohol with 35 to 100 % of alcohol according to weight under five values of temperature (0°, 10°, 15°, 20° and 30 °C).
It is necessary to thank Dmitry Ivanovich Mendeleyev that Russia was possible to give the world its famous Russian vodka. V. Pohlebkin in his article, devoted to the Mendeleyev’s research, wrote, “D. I. Mendeleyev, who had taken part in his time in the creation of the contemporary scientific technology of vodka production, insisted definitely on making the general official name “vodka” as the most exactly expressing the character of the drink.
Till the establishment of the vodka monopoly in 1894–1902, vodka had been produced very easily – by mixing up 50 % of alcohol with 50 % of water. Such a mixture gave 41–42° of alcohol in the drink. In order to get the forty-degree vodka, it was necessary not to combine volumes but to weigh alcohol precisely. Mendeleyev proved that 40°, which is indeed never got by mixing up the volumes of the water and alcohol, but only by mixing up the precise weight ratio of alcohol and water, should have been acknowledged as the ideal content of alcohol in vodka.
Thus, one litre of forty-degree vodka should weigh exactly 953 g. The alcoholic content of the alcohol-aqueous mixture, weighing 951 g, will be 41В°, and it will be 39В° in case of weighing 954 g. The physiological influence of such a mixture to organism becomes worse in both cases and, definitely speaking, both of them cannot be called vodka.
Densimeters constructed by D. I. Mendeleyev. Made in 1859-1860
Young Russian scientists-chemists. From left to right: N. Zhitinsky, D. I. Mendeleyev, A. P. Borodin, V. I. Olevinsky, I. O. Heidelberg. 1860
Dmitry Ivanovich Mendeleyev and Theozva Nikitichna Mendeleyeva (nee Leshchova; 1828–1905) – the first wife of D. I. Mendeleyev. 1862
As a result of the research of D. I. Mendeleyev, since the end of the 19
century only product containing grain alcohol mixed by water according to weight exactly till 40°, could have been regarded as Russian (or rather – “Moscow”) vodka. This Mendeleyev’s structure of vodka was patented in 1894 by the government of Russia as Russian national vodka – “Moscow Especial” (first it was named “Moscow Particular”).
As during the life of D. I. Mendeleyev his data were started to be used for the wine-making calculations in Austria, Germany and Holland.
In Imperial Russia the alcoholometrical tables were based on the archaic English and German data. The results of D. I. Mendeleyev were admitted later. In the 1920’s the special commission of the Principle Board of Weights and Measures came to a conclusion that the work of Mendeleyev was precise to the maximum. In 1927 new alcoholometrical tables, the basis of which were the results of the scientist’s research, were published.
From the very graduating the Main Pedagogical Institute, teaching took a considerable time of Dmitry Ivanovich Mendeleyev. Teacher’s work of the scientist amazes by its breadth. At first, together with general, theoretical, organic and analytical chemistry he was teaching physics and physical geography. Students not just loved the scientist, they literally worshipped him. His appearance also made a great impression. He had never delivered his lectures smoothly, but always vividly, interestingly and informally, accompanying his words with an expressive mimicry. It was difficult to take exams to him.
Dmitry Ivanovich was teaching at the University, the Institute of Technology, the Institute of the Corps of Engineers of Communications, at the Nicholas Engineering Academy, the Nicholas Engineering School and at the 2
Military School. Since 1871 he had been teaching chemistry at the Higher Female Courses. Later the number of the educational institutions, where Mendeleyev had been teaching, slightly reduced and he concentrated all his work mainly at the Institute of Technology and at the University.
Mendeleyev wasn’t only teaching but he always took part in the public life of the educational institutions, quickly reacting to the changes, which had been made in the system of Russian education. The liberal reforms of the 1860’s, which had been made by Alexander II, applied to the system of education in Russia and influenced the life of the University immediately. The statute of the University, signed by Alexander II on June, 18
of 1863, was the most liberal university regulation in Russia of the 19
– the beginning of the 20
century. The statute gave autonomy to the higher educational institution. The University’s board, the members of which were all the professors, became an independent institution. The Board had the right to choose the rector, pro-rector, deans and also professors for the vacant chairs. It was very important that the University’s board got an opportunity to divide the faculties to the branches, to join and to divide the chairs, to change them and to define which subjects should have been considered obligatory and not obligatory for students.
Having become in 1867 the head of the department of general chemistry of the physico-mathematical faculty, Mendeleyev succeeded to separate out an independent course of analytical chemistry, which had been taught by N. A. Menshutkin. Thanks to Mendeleyev’s initiative, A. M. Butlerov was invited to teach the course of organic chemistry from Kazan University in 1868. And since 1869 the chemical sciences were represented at the University by the three departments: of general and inorganic chemistry (D. I. Mendeleyev), of organic chemistry (A. M. Butlerov) and of analytical and technical chemistry (N. A. Menshutkin).
According to the Statute of 1863 the University got the right to establish scientific societies. Thus, Saint-Petersburg Society of Naturalists (1868), the Philological Society (1869) and the Physical Society (1872) appeared.
During these years D. I. Mendeleyev took an active part in the establishment of the scientific chemical society. There are notes in the diaries of the scientist of 1861–1862 about the meetings of the chemists which had become regular. At those meetings there were the majority of well-known chemists and representatives of the adjoining sciences, who worked in Saint-Petersburg. N. N. Zinin, F. F. Beilstein, L. N. Shishkov, A. A. Voskresensky, N. I. Koksharov, E. H. Lenz, B. S. Jacobi, etc. can be mentioned among them. It becomes clear from the diaries to what a great extent was the role of Mendeleyev in the establishment of the scientific chemical society. However, the dream of the scientist was realized only in 1868.
The work at the manual “The fundamentals of chemistry” takes an exclusive place in the life and activities of Dmitry Ivanovich Mendeleyev at the end of the 1860’s. Right this work led the scientist to the discovery of the periodical law of chemical elements. Mendeleyev must have started to work at the text of the manual in winter of 1867–1868, using in the process of the work the stenograms of his lectures, made by the students. The book was published in separate editions, the first of which appeared at the end of May – beginning of June of 1868. Later Dmitry Ivanovich admitted that “The Fundamentals…” was his “dear child.”
During the process of the work at the schedule of the editions of the 2
part Mendeleyev was gradually coming from grouping the elements according to their valency to their location according to the resemblance of their characteristics and atomic weight. In the middle of February of 1869 Mendeleyev, while keeping thinking over the structure of the subsequent chapters of the book, reached in real earnest the problem of creating the rational system of chemical elements. The determining stage came on February, 17
.
Anna Ivanovna Mendeleyeva (nee Popova; 1860–1942) – the second wife of D. I. Mendeleyev. Late 1870’s
Portrait of D. I. Mendeleyev made by A. I. Mendeleyeva. Oil, 1886
D.В I. Mendeleyev. 1861
