A Brief Sketch of the Life and Work of Academician G. S. Landsberg*

S. L. Mandelstam

The life path of Grigorii Samuilovich Landsberg, like that of many outstanding scientists, was poor in external events. All the brighter was his path in science. In our country, the name of G. S. Landsberg is associated with the development of spectral analysis—one of the most important branches of physics in terms of the scale and significance of its practical applications.

Grigorii Samuilovich Landsberg was born on January 22, 1890, in the city of Vologda, into the family of an official of the state forest service. Soon G. S. Landsberg’s family moved to Nizhnii Novgorod, where Grigorii Samuilovich graduated from the gymnasium with a gold medal.

During his last year at the gymnasium, because of a lung disease, G. S. Landsberg was forced to spend time in a forestry district. Here, apparently under the influence of an extraordinarily educated man, G. G. Shaposhnikov, G. S. developed an interest in the natural sciences, and in 1908 he entered the natural-science division of the Faculty of Physics and Mathematics at Moscow University. However, already a year later, thanks to close contact with N. N. Andreev, G. S. Landsberg became interested in physics and transferred to the mathematical division of the university. Landsberg preserved a close friendship with Academician N. N. Andreev to the end of his life.

Poor health forced G. S. Landsberg to take a position as a tutor and spend three years in Switzerland, from where he came to Russia to take examinations. In 1913 G. S. Landsberg graduated from the university with a first-degree diploma and was retained at the university for preparation for a professorship. From 1913 to 1915 G. S. Landsberg served as an assistant in the university physics practicum, and in 1915, together with N. N. Andreev, published his first scientific work, devoted to the manufacture of very large resistances. In the same year G. S. Landsberg was called up for military service. In 1916 G. S. Landsberg was assigned to the laboratory of the Zemsky Union; here, first as a research associate and then as deputy head of the laboratory, G. S. Landsberg carried out several investigations connected with questions of protection against asphyxiating gases. From 1918 to 1920 G. S. Landsberg was a docent at the Omsk Agricultural Institute. In 1920 he returned to Moscow and became a research associate at the Institute of Physics and Biophysics.

* Expanded contents of a report at the Joint Session of the Division of Physical and Mathematical Sciences of the Academy of Sciences of the USSR, the P. N. Lebedev Physical Institute, the Commission on Spectroscopy, and the Moscow Institute of Physics and Technology of the Ministry of Higher Education, dedicated to the memory of Academician G. S. Landsberg, March 25, 1957.

This institute, headed by Academician P. P. Lazarev, brought together the first Russian school of “second-generation” physicists—students of P. N. Lebedev. S. I. Vavilov, P. N. Velikov, P. A. Rebinder, E. V. Shpolskii, T. K. Molodyi, A. S. Predvoditelev worked there; M. A. Leontovich, B. V. Deryagin, G. A. Gamburtsev and many other major Soviet physicists began their work there. G. S. Landsberg’s interest in optics dates from this period. Optical problems at that time were central in physics and constituted one of the main directions of the institute’s work.

In 1923 G. S. Landsberg moved to Moscow University as an assistant, and then as an associate professor of the Department of Theoretical Physics. At the same time, from 1923, G. S. Landsberg was a professor of the 2nd Moscow University, now the V. I. Lenin Pedagogical Institute; he continued his activity at this institute as head of the physics and technology division until 1931.

In 1925 Academician L. I. Mandelstam moved to Moscow University, and he had a profound influence on all the subsequent activity of Grigorii Samuilovich Landsberg.

The first problem in the joint investigations of G. S. Landsberg and L. I. Mandelstam was the study of Rayleigh scattering of light in crystals, one of whose tasks was the investigation of the fine structure of the line of scattered light. In 1918 L. I. Mandelstam had theoretically considered the existence of such a structure, caused by modulation of the Rayleigh line by thermal waves propagating in the crystal. Before proceeding to an experimental study of this phenomenon, it was necessary to investigate the very phenomenon of Rayleigh scattering in crystals, which at that time had been well studied in gases but remained undetected and unstudied in solids. The principal difficulty of these investigations lay in the impossibility of separating, by the usual methods employed for liquids and gases, the true molecular scattering from the various kinds caused by inhomogeneities and inclusions in the crystal. In his very first work G. S. Landsberg made a step of great importance, which determined the success of the subsequent investigations: to isolate the molecular scattering, he used the temperature dependence of the intensity of the scattered light.

This work was the beginning of a large cycle of investigations by G. S. Landsberg and his students devoted to the study of Rayleigh scattering, which remained one of the principal directions of Grigorii Samuilovich’s scientific research until the end of his life.

After the presence of molecular scattering of light in quartz had been reliably established, G. S. Landsberg and L. I. Mandelstam began to investigate the spectral composition of the scattered light. These studies led, as is well known, to the discovery of an entirely new phenomenon, which received the name combination scattering of light.

In the autumn of 1927 it was found that satellites appeared in the spectrum of light scattered in a quartz crystal. The change in the wavelength of the scattered light, however, proved to be considerably greater than that due to modulation by thermal waves. It became clear that a new physical phenomenon had been found, caused by modulation of the light by faster, intrinsic infrared vibrations of the molecules.

In February 1928 G. S. Landsberg carried out numerous control experiments, and M. A. Leontovich performed the corresponding calculations, which confirmed these considerations. The first communication about this discovery was sent to press only on May 6, 1928, after repeated additional-

...checks. In this communication the frequencies of the satellites for quartz are given and a comparison is made of the displacement of the satellites with the intrinsic infrared frequencies of quartz. In addition to this communication, made at the proof stage, data are also presented for Iceland spar.

The change in the wavelength of light upon scattering in liquids was simultaneously observed by Raman, who reported his discovery by telegraph several weeks before the communication of G. S. Landsberg and L. I. Mandelstam.

The discovery of the combination scattering of light is one of the most significant discoveries in physics in recent decades, the importance of which for physics and chemistry is difficult to overestimate. It immediately attracted the attention of scientists throughout the world, and at present many thousands of investigations are devoted to questions of the combination scattering of light and to its applications for solving a great variety of physical and chemical problems.

The new phenomenon was investigated theoretically and experimentally in a series of works by L. I. Mandelstam, G. S. Landsberg, I. E. Tamm, M. A. Leontovich, and their collaborators. The classical and quantum theories of the phenomenon were given, the temperature dependence of the intensity of the red and violet satellites was studied, and the significance of the new phenomenon for a broad range of physical, physicochemical, and chemical problems was clarified.

Diverted by the study of the new phenomenon from continuing their investigations of Rayleigh scattering, G. S. Landsberg and L. I. Mandelstam later returned again to these questions.

Grigory Samuilovich and his pupils continued investigations of the intensity of scattered light in crystals: the absolute intensity of scattering in quartz was measured (together with K. S. Vul’fson), scattering in rock salt was investigated (together with S. L. Mandelstam), and anisotropy of scattering was discovered (K. S. Vul’fson, G. P. Motulevich, M. A. Lombert). A comparison of the reliable experimental results obtained with theoretical calculations showed the unsatisfactory nature of the theory, and at the initiative of G. S. Landsberg, M. A. Leontovich developed a new theory of scattering in crystals, subsequently developed in a number of works by the pupils of G. S. Landsberg.

In 1930 G. S. Landsberg and L. I. Mandelstam discovered the presence of a fine structure of the Rayleigh line, mentioned above, which, because of the imperfection of the apparatus at their disposal, appeared only as a broadening of the line. E. F. Gross, having studied this question at their suggestion with more perfect apparatus, was able to obtain the predicted structure of the line in crystals, and then to discover these phenomena in liquids.

The close connection between the problems of light scattering and the character of propagation in a medium of high-frequency ultrasonic oscillations and their damping prompted L. I. Mandelstam and G. S. Landsberg to undertake special extensive investigations of the propagation of ultrasonic waves in crystals and liquids (P. A. Bazhulin, A. A. Shubin, and others). These investigations soon acquired independent interest and yielded a number of important results, among which may be mentioned the experimental determination of the so-called second coefficient of viscosity.

The investigation of certain questions of resonance fluorescence led G. S. Landsberg and L. I. Mandelstam in 1931 to the discovery of the phenomenon of selective scattering of light, consisting in a sharp increase in the intensity of scattered light near the resonance lines of atoms. This phenomenon caused an extensive discussion in the literature; in subsequent works it was subjected by G. S. Landsberg to detailed study.

In 1932 G. S. Landsberg was elected a corresponding member of the Academy of Sciences of the USSR.

The beginning of G. S. Landsberg’s investigations in the field of spectral analysis, which very quickly became the second main direction of his work, dates from this same time.

In those years our country was engaged in grandiose construction. New branches of industry and gigantic factories were being created, and G. S. Landsberg, as a true scientist, was one of the first physicists to feel the necessity of the participation of physical science in this work of national importance. G. S. Landsberg became interested in emission spectral analysis. At that time investigations in spectral analysis were being carried out abroad (W. Gerlach, G. Scheibe, F. Löwe, W. Twyman) and had begun to develop in the USSR (A. N. Filippov, S. A. Borovik, A. K. Rusanov), but in essence spectral analysis had not yet gone beyond the bounds of a laboratory method.

G. S. Landsberg saw the potential possibilities inherent in spectral analysis, making it possible to develop it into a powerful technical method for controlling the composition of materials. Soon the first concrete task presented itself. Among the new plants then being created, the Moscow Automobile Plant (now named after Likhachev) enjoyed the country’s special attention. The plant was in a feverish state; Pravda printed daily summaries of the number of cars produced per day. Among G. S. Landsberg’s pupils was a former worker of the plant, S. V. Tulyankin, and G. S. Landsberg, as always not limiting himself to the role of scientific supervisor and being aware of all the interests of his pupils, found out that one of the “bottlenecks” in the automobile plant’s production was the enormous rejection rate in the casting of malleable cast iron. It turned out that this was due to the lengthiness and imperfection of the methods of chemical analysis. G. S. Landsberg decided to try to apply spectral analysis for rapid control of cast-iron melting. A considerable part of G. S. Landsberg’s collaborators was transferred to this work (S. M. Raiskii, S. L. Mandelstam, P. A. Bazhulin, A. R. Striganov, N. N. Baskakov, V. V. Tseitlin, S. M. Levi; subsequently F. S. Baryshanskaya, L. M. Ivanov, V. G. Kordinskii, and others joined them), and the work proceeded at a very rapid pace. Here a very characteristic feature of G. S. Landsberg manifested itself: whenever he considered a given question important, he subordinated to its solution all his forces and did not stop before any scientific or organizational difficulties until he had obtained a completed solution of the problem. So it was this time as well. G. S. Landsberg, occupied with interesting investigations in the field of “pure” physics, considered it necessary to devote to this applied problem the lion’s share of his time and strength and, despite very great difficulties, was able to solve it. It was followed by a second task—the sorting of alloyed steels. At that time plants, consuming an enormous quantity of alloyed steel, received it in a mixed-up form; this led to considerable rejects in production. G. S. Landsberg solved this problem too, developing for rapid analysis of steel a special instrument—the styloscope, which plays such an important role in modern spectral analysis.

The solution of these first two tasks required investigations to develop methods for exciting the spectrum, observing the spectrum, and measuring the intensity of spectral lines. The difficulty of the problem was aggravated by the fact that it was necessary to create methods and apparatus that would operate continuously and reliably under production conditions (shop, warehouse) and whose servicing would be within the power of low-skilled personnel. Already in the first work ways of solving these problems were found, and in the small workshops of the Optical Laboratory of Moscow State University the manufacture of specially developed apparatus was organized.

Under the guidance of G. S. Landsberg the first cadres of spectroscopist-analysts were trained, and spectral analysis was introduced at several plants.

The period of Grigorii Samuilovich Landsberg’s activity described here belongs to the heyday of physics at Moscow University.

Working there were Academicians S. I. Vavilov, L. I. Mandelstam, and a large group of their associates and pupils: I. E. Tamm, M. A. Leontovich, S. E. Khaikin, A. A. Andronov, G. S. Gorelik, A. A. Witt, B. M. Hessen, V. L. Levshin, and others, as well as many talented young people.

At the university a reorganization of the teaching of physics was carried out, beginning with the general course in physics, the course in theoretical physics, and special courses, and ending with instructional laboratories. No less intensive was the research work conducted in various fields of physics. A variety of colloquia, seminars, and lectures attracted a numerous audience of Moscow physicists, and the university became a natural center of physics in Moscow.

Grigorii Samuilovich Landsberg headed the Optical Laboratory of the Institute of Physics of Moscow State University from 1925 to 1941, and from 1932 to 1935 also the Department of General Physics and the Physics Cabinet, and was one of the central figures in this extensive activity.

In 1934 the Physics Institute of the Academy of Sciences of the USSR moved to Moscow; a large group of university workers transferred to it, and G. S. Landsberg, at the suggestion of S. I. Vavilov, assumed the organization and direction of the Optical Laboratory of the Physics Institute of the Academy of Sciences, while retaining his leadership of the Optical Laboratory and his lectures at Moscow State University. The Optical Laboratory of the Physics Institute of the Academy of Sciences gradually became the principal center of Grigorii Samuilovich’s scientific activity. In this laboratory research on Rayleigh and combination scattering of light, on ultrasonics, and also work on spectral analysis continued on a broad front.

The works of this period are characterized by the development of new directions of research, above all in the field of combination scattering of light. Here it is necessary to point to G. S. Landsberg’s extremely difficult experimental work on the study of second-order lines (together with B. I. Malyshev); owing to the difficulty of carrying out the experiment, for a number of years it remained the only investigation of its kind. Of special interest to G. S. Landsberg was the possibility of using the method of combination scattering of light for studying intermolecular interactions. The so-called “hydrogen bond,” occupying, as it were, an intermediate position between intramolecular and intermolecular forces, was chosen as the principal object of investigation. In a cycle of works by G. S. Landsberg and his pupils (V. I. Malyshev, S. A. Ukholin, I. A. Yakovlev, M. I. Batuev, A. S. Eliner, F. S. Baryshanskaya, and others), numerous substances containing the OH group, in various states of aggregation, were studied. These investigations made it possible to identify spectroscopic features characterizing the OH group, to establish the conditions leading to the formation of a “hydrogen bond,” and to discover, in a number of solutions and pure liquids, the simultaneous existence of associated complexes and dissociated molecules.

To this time also belongs the establishment of close contact between G. S. Landsberg and the school of organic chemists headed by Acad. N. D. Zelinskii and Acad. B. A. Kazanskii; this contact later proved very fruitful. An extensive program of joint investigations was developed and began to be carried out, in which the chemists prepared extremely pure individual hydrocarbons, while the Optic—

the laboratory of the Physics Institute of the Academy of Sciences under the direction of G. S. Landsberg carried out a comprehensive investigation of their Raman spectra.

At the same time, work was being conducted on the development of methods of emission spectral analysis. The processes of excitation of the spectrum in an arc and a spark were studied (S. M. Raiskii, S. L. Mandelstam, N. N. Sobolev); new analytical procedures were developed (S. M. Raiskii, F. S. Baryshanskaia, S. L. Mandelstam, V. V. Nedler, L. M. Ivantsov); and designs of spectral and auxiliary instruments were created and improved (L. M. Ivantsov, V. F. Smirnov, K. P. Krylov). With the direct participation and under the leadership of G. S. Landsberg, spectral analysis was placed on a firm scientific and practical foundation, both with regard to the development of the method and its physical substantiation, and in the creation of spectral apparatus and the organization of its production.

From the very beginning G. S. Landsberg saw that this work could be effective only with the participation of a broad circle of workers; he trained leaders and personnel for central laboratories in several branches of industry (A. R. Striganov, K. A. Sukhenko, V. F. Smirnov, L. E. Vvedenskii, P. A. Sakharikov, and others), and in 1937 he organized the Commission on Spectroscopy of the Academy of Sciences of the USSR. The Commission included major scientists and practical workers—employees of higher educational institutions, branch institutes, and factory laboratories—and in its first years the Commission concentrated its principal attention on the development of work in spectral analysis.

In 1940 G. S. Landsberg was awarded the Stalin Prize for his work on spectral analysis.

At the beginning of the Great Patriotic War, Grigorii Samuilovich Landsberg moved with the Physics Institute of the Academy of Sciences of the USSR to Kazan. There, under the difficult conditions of wartime, G. S. Landsberg quickly developed work in spectroscopy and optics and directed it toward assistance to the defense industry and the front. G. S. Landsberg organized optical workshops of the Academy of Sciences, brought in a group of his collaborators to work in them (S. M. Raiskii, V. G. Koritskii, V. I. Malyshev), and set up production of a simplified model of a styloscope. During the war years more than 300 of these instruments were produced and delivered to the tank, aviation, and other branches of the defense industry and to repair units of the Red Army. These instruments played a major role in the production activity of factories under wartime conditions, as well as in the immediate repair of military equipment. At the same time, methods of spectral analysis of light alloys and special steels were developed, extensive work was carried out to establish spectral laboratories at factories and to set up production of spectral standards. Work in the field of Raman scattering of light was directed toward the creation of a method of molecular analysis of gasolines, which already in its first version could be used to solve important defense tasks connected with the investigation of captured gasolines.

In 1946 G. S. Landsberg was elected a full member of the Academy of Sciences of the USSR.

The postwar years led to the further development of the main directions of Grigorii Samuilovich Landsberg’s research. In the works of G. P. Motulevich, Z. M. Turovtseva, and others, the theoretical and experimental study of classical scattering in crystals, begun by G. S. Landsberg more than 25 years earlier, was completed. An extensive series of studies of molecular scattering in liquids, including the study of the wings of Rayleigh lines, was carried out by I. L. Fabelinskii. At the same time G. S. Landsberg posed a new problem—the investigation of molecular scattering in viscous liquids and amorphous bodies; work

T. S. Velichkina yielded very interesting results and showed the promise of further development of this line of research.

Studies of the hydrogen bond were continued. In a series of works by G. S. Landsberg and F. S. Baryshanskaya, using a very subtle method, the hydrogen bond in crystals whose molecules contained an OH group was investigated, which made it possible, in particular, to establish the radius of action of the forces of the hydrogen bond.

T. S. Landsberg among a group of members of the Commission on Spectroscopy during the All-Union Conference on Spectroscopy in Sverdlovsk (1950).

In the study of the aggregate state of matter, alongside methods of combination scattering of light, methods of infrared spectroscopy were widely employed. In these investigations, further important results were obtained in establishing the existence of associations of molecules in the gaseous phase caused by the hydrogen bond (A. A. Shubin), as well as in studying the processes of transition of a substance from one aggregate state to another (V. I. Malyshev, Kh. E. Sterin, I. I. Sobelman). Studies of the spectra of combination scattering of individual hydrocarbons were widely continued (P. A. Bazhulin, M. M. Sushchinskii, S. A. Ukholin, Kh. E. Sterin, V. T. Aleksanyan, and others). Along with the measurement of intensity, methods were developed for measuring depolarization and the widths of lines of combination scattering, and spectra of more than 100 individual hydrocarbons were studied. The results of 20 years of research in this field are set forth in the monograph by G. S. Landsberg, P. A. Bazhulin, and M. M. Sushchinskii, The Principal Parameters of the Spectra of Combination Scattering of Hydrocarbons, which was published in 1956 and occupies

...an important place in the world literature on molecular spectroscopy. At the same time, as a result of the joint efforts of the groups headed by G. S. Landsberg and B. A. Kazanskii, the method of analyzing mixtures of hydrocarbons was considerably improved. At present this method is finding ever wider use in practice; in particular, with its aid studies have been carried out on the oils of most of the deposits of the USSR.

The choice of the simplest hydrocarbons as objects of investigation proved very successful. It made it possible not only to solve an important practical problem—the creation of a method for analyzing light petroleum products—but also provided material for the development of important physical investigations. The accumulated factual material on the frequencies, intensities, polarizations, and widths of the lines of combination scattering made it possible to introduce the concept of characteristic parameters inherent in definite structural components of molecules and retained in the transition from one compound to another. This provides a firm physical basis for the structural analysis of complex organic compounds. Grigorii Samuilovich Landsberg also posed the problem of calculating the vibrational spectra of molecules on the basis of their structural parameters, which is the key to understanding the experimentally observed regularities in spectra. This problem is being solved by M. M. Sushchinskii with the aid of electronic computing machines and has already yielded interesting results.

In his later years as well, Grigorii Samuilovich did not cease to devote very great attention to the development of methodological questions in spectroscopic investigations. Under his direction a number of studies were carried out on the theory of spectroscopic apparatus, and on the creation of new instruments and methods of measurement.

In a brief essay it is, of course, impossible to set forth all the work performed by Grigorii Samuilovich. I have wished to try to give a brief characterization only of the main directions of his investigations. However, what has already been said is enough to obtain a clear idea of the scale of all that was done by Grigorii Samuilovich Landsberg.

Investigations in optics belong among the most difficult and delicate studies in the field of experimental physics. In turn, investigations on light scattering and spectroscopy are the most difficult in this difficult field. Grigorii Samuilovich possessed the brilliant gift of an experimenter. He set before himself and his collaborators the most complex tasks and always found their successful solution. We, his older pupils, had the good fortune to work systematically with Grigorii Samuilovich, and all of us retain in our memory the remarkable love and mastery in experiment that characterized his work.

G. S. Landsberg always devoted great attention to questions of experimental methodology. All of G. S. Landsberg’s works are a model of classical rigor of experiment and irreproachable reliability of results. Later investigations, with more perfected means, could refine one or another of G. S. Landsberg’s results, but there was never a case in which any result found by G. S. Landsberg was not reproduced or was withdrawn by him. This irreproachability of his work is characteristic not only of G. S. Landsberg’s personal investigations, but also of all the work done under his direction. We, his pupils, old and young, knew Grigorii Samuilovich’s relentless exactingness toward the quality of his own and our work, toward the quality of publication. We had many times to redo what seemed already to be a fully completed investigation or article. When G. S. Landsberg was satisfied, this was the highest criterion of the soundness of the work.

A Brief Sketch of the Life and Work of Academician G. S. Landsberg

G. S. Landsberg’s scientific investigations cannot be separated from his pedagogical activity. After the interruption caused by the Patriotic War, and after a brief period as a professor at the Moscow Engineering-Physics Institute (1945–1947), G. S. Landsberg resumed his work at Moscow University as one of the organizers of its new Physico-Technical Faculty, reorganized in 1951 into the Moscow Institute of Physics and Technology. G. S. Landsberg established a specialization in optics, headed the Department of Optics and Spectroscopy, and took an active part in all the work of this new and unusual educational institution.

G. S. Landsberg approached teaching with immense love and devoted to it a considerable part of his time and energy. He taught numerous courses, including the course in general physics and various special courses that he created for the first time (atomic theory, molecular scattering of light, and others). The lectures in the general physics course that he delivered at Moscow University and, in recent years, at the Moscow Institute of Physics and Technology always attracted, along with students, a large audience of graduate students, teachers, and research workers. G. S. Landsberg loved giving these lectures and continued to do so until his final years, astonishing his colleagues with his tirelessness and thoroughness in preparing lecture materials and demonstrations. These lectures left an indelible memory in many generations of physicists.

G. S. Landsberg’s pedagogical activity was expressed not only in lectures. A characteristic feature of G. S. Landsberg was his continuous, close contact with young people. He was always surrounded by talented students, graduate students, and collaborators. G. S. Landsberg involved students in research work at very early stages, and his young collaborators in teaching activity. The school of G. S. Landsberg produced many prominent scientists working in the scientific institutions, higher educational establishments, and industry of our country. To belong to this school is a high and honorable title.

G. S. Landsberg paid considerable attention to literary work, regarding it as an integral part of a scientist’s activity. Even in his younger years G. S. Landsberg wrote a great many reviews, abstracts, and survey articles, articles for encyclopedias, and translated and edited numerous books. In 1929, together with B. A. Vvedensky, he wrote the book The Modern Doctrine of Magnetism. In 1934 G. S. Landsberg wrote the fundamental course Optics, which is about to appear in its fourth edition and which is one of the best textbooks on optics in world literature. This textbook essentially revolutionized the teaching of optics in higher educational institutions. At the initiative and under the editorship of G. S. Landsberg, the three-volume Elementary Textbook of Physics was created, playing such an important and already quite tangible role in raising the level of physical knowledge among student youth. His last work was the publication of Fresnel’s Selected Works, for which G. S. Landsberg wrote a brilliant introductory article.

Scientific-organizational activity occupied an enormous place in G. S. Landsberg’s work. It proceeded along many channels; chief among them was the Commission on Spectroscopy. I have already spoken of the role played by the Commission in the first years of its existence in the development of spectral analysis. To a significant degree thanks to the Commission’s activity, spectral analysis has now become in our country one of the principal methods of production control at plants in the metallurgical, aviation, machine-building, and other branches of industry, yielding an enormous technical and economic effect. Spectral

analysis turned into an independent scientific discipline, with a deeply developed theory, diverse experimental methods, and broad practical applications. In the laboratories of hundreds of factories, research institutes, and higher educational institutions, scientific research is being conducted on the further development of spectral analysis. Our country possesses an army of many thousands of spectral analysts and first-rate domestic apparatus. G. S. Landsberg was the acknowledged leader in this development of spectral analysis.

G. S. Landsberg and Corresponding Member of the USSR Academy of Sciences S. Frisch during a visit to the observatory in Utrecht (Holland). On the right is the director of the observatory, Professor Minnaert (1956).

No smaller a role was played by the Commission in subsequent years, directing and coordinating work in all spectroscopy in the USSR. This work, often associated with very great difficulties, required from G. S. Landsberg enormous exertion and self-sacrifice. G. S. Landsberg approached the work of the Commission with a tremendous sense of responsibility and, up to the last days of his life, took personal part in all its major and minor affairs. The Commission on Spectroscopy possesses no fixed “rights,” yet to a considerable degree, thanks to the untiring activity of G. S. Landsberg, its scientific and moral authority is so high and universally recognized.

Under the direct leadership of G. S. Landsberg, Soviet spectroscopists gathered at their All-Union conferences (more than 1,500 spectroscopists took part in the work of the most recent, Tenth Conference, in 1956), and all their participants keenly felt how much G. S. Landsberg’s personal participation in them contributed to the success of these conferences.

G. S. Landsberg was personally acquainted with, and maintained contact with, very many spectroscopists. Dozens of physicists, chemists, and engineers appealed to him, personally and in writing, for numerous consultations and for help in their work, and each of them received exhaustive assistance and support.

G. S. Landsberg carried on active work in the Society for the Dissemination of Political and Scientific Knowledge, where he was head of the physics section. He was one of the organizers and a member of the editorial boards of a number of scientific journals, raising the level of publications to an extraordinarily high standard, and was also an active participant in many other scientific and public undertakings.

All of G. S. Landsberg’s activity was an inseparable organic fusion of the scientist and the human being. G. S. Landsberg did not separate science from life, or life from science: every step he took in science was made in the name of the life around him, and his whole life, down to its very last hours, he devoted to the service of physics.

G. S. Landsberg had an unusually strong sense of duty and responsibility. One could not hear from him the phrase with which we so often soothe our conscience: “Well, I have done everything I could.” G. S. Landsberg did not cease his efforts until he had brought to a real conclusion the work that he considered important and necessary. He was a man of great courage and principle, who in his lifetime did not commit a single act that required compromise with his conscience, either in great matters or in small ones. G. S. Landsberg was deeply proud of our country and of its successes. He was a patriot of his Motherland in the highest sense of the word.

G. S. Landsberg was distinguished by exceptional moral purity; his thoughts, judgments, and actions were marked by a special nobility, benevolence, and sensitivity. He was a man with a very broad range of interests: travel in his younger years, chess, gardening, and visits to art galleries in later years were for him the principal pleasures in the few hours of rest in which he allowed himself to tear himself away from work.

G. S. Landsberg had a faithful companion in life—his wife F. S. Baryshanskaya, an indefatigable assistant in his scientific investigations on the scattering of light and spectral analysis.

In our lives—the lives of his older and younger co-workers—Grigorii Samuilovich occupied a quite special place. For us he was not only an outstanding scientist with a world name, but also a beloved teacher. He taught us physics, the high duty of a scientist, and the responsibilities of a Soviet citizen. G. S. Landsberg was also, for us, simply a person close to us, to whom we—and dozens and hundreds of acquaintances and strangers—turned with many matters, beginning with new physical ideas and ending with the most ordinary everyday concerns. And for each of us Grigorii Samuilovich did very, very much good.

G. S. Landsberg left Soviet science a great legacy. It is a whole series of scientific directions, both purely theoretical and applied; some of them have already been advanced far, while others were only begun in the last years. It is also a series of major scientific-organizational undertakings for the further development of spectroscopy and its applications in the Soviet Union. Our duty—the duty of his pupils and co-workers—is to continue and develop this enormous work.

In all our activity we shall always keep before our eyes the bright image of Grigorii Samuilovich Landsberg—scientist, teacher, and human being.