DMITRY SERGEEVICH ROZHDESTVENSKY

K. K. Baumgart, Leningrad

The activity of Academician Dmitry Sergeevich Rozhdestvensky, who died on June 25, 1940, is striking in its versatility and in the significance of the results he obtained. Dmitry Sergeevich was not only a scholar of the study, the author of classical investigations in optics unsurpassed to this day—he was at the same time a scientist wholly and to the end Soviet, a genuine builder of socialism. His great temperament and sense of responsibility to society impelled him onto the path of practical activity. Dmitry Sergeevich was the initiator and organizer of a number of undertakings of enormous state importance: he organized the State Optical Institute, he was one of the chief creators of the Soviet optical industry, he reformed the teaching of physics at Leningrad University. As a person, Dmitry Sergeevich was remarkable for his purposefulness, moral strength, breadth, and boldness of interests.

All aspects of Dmitry Sergeevich’s activity are so closely interwoven that any subsequent division of them is inevitably somewhat artificial.

1. Years of study and scientific works. Dmitry Sergeevich was born on April 7, 1876, in the family of an educator, a history teacher in a secondary school, later a director of public schools. He received his secondary education at the Sixth St. Petersburg Gymnasium, from which he graduated in 1894 with a silver medal; his higher education was at Petersburg University, in the Mathematical Division of the Faculty of Physics and Mathematics, where he chose physics as his specialty. His first scientific supervisor was Prof. N. G. Egorov, under whom D. S. undertook his candidate’s experimental work in the field of fluorescence. After graduating from the university, in 1900, D. S. worked for a year as a laboratory assistant at the Military Medical Academy, and then in the autumn of 1901 went to Leipzig to the well-known experimentalist Prof. Wiener, where he worked for about a year (two semesters). Under Wiener he carried out experimental work on the topic: the effect of fluorescence on the electrical conductivity of solutions. The work gave a negative result. The expected effect was not detected. Wiener did not venture to publish the work of a beginning scholar with a negative result. Later, in the work of other persons, it turned out that the observations

Dmitry Sergeevich Rozhdestvensky

(1876–1940)

Dmitrii Sergeevich’s [conclusions] were entirely correct, and fluorescence has no effect whatever on electrical conductivity.

From the autumn of 1902 Dmitrii Sergeevich began working at the Physical Institute of Petersburg University as a laboratory assistant (in present terminology, an assistant). He again spent the summer semester of 1903 abroad, this time in Giessen with the well-known optician Drude. There he studied the influence of temperature on the optical constants of metals and, in one summer, managed to obtain some numerical data and draw certain conclusions. These results and conclusions are presented in Drude’s work “Optical Properties and Electron Theory,” printed in 1904 with D. S. Rozhdestvenskii’s name indicated. His work with Wiener and Drude gave Dmitrii Sergeevich a great deal. He saw large laboratories and became acquainted with European scientific schools.

When, in the autumn of 1903, Dmitrii Sergeevich began independent scientific work, the situation at Petersburg University was as follows: the professors of physics I. I. Borgman and O. D. Khvolson had rendered great services to the university, themselves carried on scientific work, and were known abroad, but neither one nor the other had created a school. Moreover, neither one nor the other worked in the field of optics. Nor could N. G. Egorov direct Dmitrii Sergeevich. Dmitrii Sergeevich himself chose a topic for himself and worked entirely independently, acquiring experimental skill in the very course of the work. The topic was very modern and vital for the epoch of the “quasi-elastic electron” as a source of light vibrations. It was “anomalous dispersion in sodium vapor.” According to the conclusions of electronic optics, it promised the possibility of determining the number of vibrators in the atom and the relative strength of the vibrators (in doublets). This topic is fully relevant even in our own days of quantum optics. At the same time, it is very difficult experimentally. Naturally, the work dragged on. Only in 1909 did Dmitrii Sergeevich make his first report in the Physics Section of the Russian Physico-Chemical Society. The report made a very strong impression. By that time Dmitrii Sergeevich had fully mastered the technique of his experiment and had devised his own method, which in sensitivity surpassed all previously known methods a hundredfold. Suffice it to say that Loria, who at about the same time published work on anomalous dispersion in sodium vapor, could not even come sufficiently close to the absorption line, whereas D. S. determined, between the lines \(D_1\) and \(D_2\), eighty separate points. The first work was followed by a series of others (see the list at the end of the article), which revealed all the possibilities contained in D. S. Rozhdestvenskii’s “hook method.”

Both of Dmitrii Sergeevich’s dissertations are devoted to anomalous dispersion. This series of investigations made D. S.’s name well known abroad. His method is presented in all physics courses; his photographs are reproduced as the best and still unsurpassed, although many people, both in our country and abroad, work on anomalous dispersion. They all work by Rozhdestvenskii’s method, giv—

thereby obtaining the most accurate figures concerning the number and strength of the vibrators in the atom, and data for testing various theories of dispersion.

In the last year of his life Dmitrii Sergeevich returned to his first topic. Having included King’s furnace in his arrangement, he investigated anomalous dispersion in pairs of refractory elements, for example chromium. This work was carried out with great success and brilliance jointly with the laboratory assistant N. P. Penkin; it was fully completed, and Dmitrii Sergeevich even managed to write an article about it.

The second brilliant series of Dmitrii Sergeevich’s works belongs to the period from 1919 to the beginning of the twenties and, for the most part, was carried out during the period of the complete blockade of the USSR. Relying on Bohr’s theory, Dmitrii Sergeevich makes a number of brilliant conclusions, first concerning the spectra of the “hydrogen-like” elements of the first group of the periodic system, and then concerning the spectra of the ionized elements of other groups. Proceeding from the similarity of distant orbits (and distant terms) in hydrogen and in hydrogen-like elements, Dmitrii Sergeevich establishes the identity of the number of electronic orbits in the alkali metals and in hydrogen and unambiguously indicates their correspondence. This was a result of enormous importance; the general scheme of levels is extraordinarily similar to the schemes of our own day. Further, Dmitrii Sergeevich explains in a new way, by an internal magnetic field, the formation of doublets in the spectra of the alkali metals, rejecting Sommerfeld’s incorrect, relativistic interpretation of the doublets. He is the first to interpret correctly the spectrum of ionized magnesium, mercury, and later neon (in doing so he introduced the idea of double jumps of electrons). He gives a scheme of the lithium atom.

Subsequently, when the blockade of the USSR had been lifted, it turned out that several outstanding physicists in Europe had arrived at the same conclusions by other paths; moreover, D. S. Rozhdestvenskii’s path is favorably distinguished from theirs by its clarity.

Dmitrii Sergeevich’s works led to the initiation of a large number of experimental investigations in the State Optical Institute, which he had organized. These works also had the significance that, after the blockade was broken, the work of the institute’s young collaborators, Dmitrii Sergeevich’s pupils, proved to be fully on the level of Western European work and, in some respects, ahead of it.

The third large series of Dmitrii Sergeevich’s works belongs to the last five years of his life and concerns the theory of the microscope. As is known, even Rayleigh had cast doubt on the diffraction theory of image formation in the microscope given by Abbe. Later, several outstanding physicists introduced changes into Abbe’s theory, among them Academician L. I. Mandelstam. D. S. analyzed this question and went considerably further than his predecessors. He set forth the results of his work in three articles, the first of which is devoted to the question of microscope illumination. D. S. shows that, with the proper construction of the optical parts of the microscope, a comparatively weak light source is sufficient to provide excessive illumination of the field of view. This work must have an effect

on the construction of microscopes. In the second article, Dmitrii Sergeevich examines the question of the formation of the image of transparent objects in a microscope, i.e., the case when the principal factor in the creation of the image is the difference in the refractive indices of the various parts of the microscopic object. Finally, in the third and most important article, which appeared in 1940, Dmitrii Sergeevich deals with the role of coherence of rays in the creation of the image. D. S.’s works on microscopy are still little known to specialists, but there can be no doubt that, when they become known and are evaluated, they will take a high place among the fundamental classical investigations in the field of optics.

In addition to the above-mentioned three large series of works, Dmitrii Sergeevich also has a number of separate works (see the list, Nos. 4a, 4b, 7, 17, 18, 19, 20, 22, 23, 28, 29, 30, 31, 32), each of which is of very great interest and deserves special study. From among these works let us cite, for example, one—his report at the Mendeleev Jubilee Congress of 1934 on the topic “The Periodic Law of the Elements on the Basis of Spectral Analysis.” This report, for which Dmitrii Sergeevich prepared for a very long time, developed into a large scientific investigation with a number of original ideas, with a new treatment of the question, and with diagrams and drawings composed in an entirely original way. These diagrams clearly reflected the absence of the necessary spectroscopic data in the field of the rare earths. D. S., with his usual energy and efficiency, carried through in the Presidium of the Academy of Sciences the organization, under the Academy of Sciences, of a special Commission on the Rare Earths, which he then headed; and now, in the four years of the Commission’s existence, its workers (all pupils of D. S. and pupils of his pupils) have issued several dozen printed works on the spectroscopy of the rare earths, containing very valuable data in this unexplored field.

2. D. S. Rozhdestvenskii as a university teacher. Dmitrii Sergeevich began his work at Petersburg (now Leningrad) University in the autumn of 1902, at first as an assistant (laboratory assistant, according to the terminology of that time) in the students’ practicum. He devoted much labor to improving the quality of work in the students’ physical laboratories; he himself created a special optical laboratory with work of an advanced type. But D. S.’s chief merit lies in the creation of a scientific laboratory in optics. He began by taking an active part in supervising students’ candidate theses and soon acquired great authority among them thanks to his extensive knowledge, the abundance of his own ideas, and his unusually conscientious attitude toward his duties as adviser. They began to come to him also for topics themselves, and soon after he had completed his first major work on anomalous dispersion, his own scientific school began to gather around D. S. (among his first pupils were L. D. Isakov and V. M. Chulanovskii). This to a significant degree raised the whole pace of work in the Physical Institute of the University, and led to a great—

to the general revival of work and the rapid growth of the institute’s scientific equipment. Later the scientific school of D. S. Rozhdestvenskii became the largest in the Soviet Union. It developed after the revolution in the Optical Institute organized by Dmitrii Sergeevich. According to an approximate count, from Dmitrii Sergeevich’s school came ten scientists with European reputations (among them two academicians) and up to forty simply good scientists. Here we have in mind only those persons who studied directly under D. S. The numerous “scientific grandchildren” of Dmitrii Sergeevich—that is, the pupils of his pupils, who formed independent scientific schools—are not counted. Few scientists in our country or abroad have had so large a scientific progeny.

The lectures that Dmitrii Sergeevich delivered first as a privat-docent (from 1912) and then as a professor of the University (from 1915) were extraordinarily interesting, substantial, and always attracted students.

After the October Revolution Dmitrii Sergeevich conceived a general and radical reform of the entire system of teaching physics at Leningrad University, which he carried out in the Physics Department of the Physico-Mathematical Faculty, specially formed at that time by the People’s Commissariat of Education. Before the revolution, mathematicians, mechanicians, astronomers, geodesists, physicists, and geophysicists studied together in the mathematical divisions of the physico-mathematical faculties. Instruction was coordinated with the interests of the mathematicians and partly the mechanicians; the various branches of mathematics were covered in detail, but physicists received the information they needed so late that they could no longer apply it in the presentation of the special, mathematical sections of physics. The same was true of mechanics; its teaching ended in the final year of the University, whereas physicists needed it much earlier. All this so constrained the teaching of physics that it allowed only the foundations of theoretical physics to be included in the curriculum and did not allow instruction in the modern branches of physics to be developed. The reform consisted in the creation, for physicists, of a special course in mathematics, which in its main parts was to be taken in the first and second years, and of a special course in mechanics, which ended in the third year. Thus, in the senior years it became possible to develop the teaching of special courses in mathematics and mechanics. Time was also freed for laboratories and scientific work.

The reform, at first adopted not without objections, fully justified itself. Leningrad University was the first to carry out the reform; Moscow University joined it only much later.

3. Work for industry and the organization of the State Optical Institute. Dmitrii Sergeevich was always close to the idea of the interaction of science and practice, and therefore he was always fascinated by the problems of optical engineering. The world imperialist war for the first time brought to the fore the question of creating in the country its own optical industry. D. S. was drawn into this undertaking, which received its solution only under Soviet power.

Under the direction of Dmitrii Sergeevich, I. E. Aleksandrov prepared at the Physics Institute of Petrograd University the first plane-parallel plate with surfaces flat to within one-tenth of a wavelength and with an angle between the surfaces not exceeding tenths of a second. Such plates had previously always been ordered from abroad. This was the first genuine precision work in optics carried out in Russia. It found factory application already in our own time (1918), and from it one must date the beginning of the Soviet precision optical industry, in the creation of which Dmitrii Sergeevich took an active part.

One of D. S.’s chief services to the optical industry was the solution of the problem of melting optical glass in the Soviet Union. It is well known how difficult this task is. The requirements imposed on optical glass with respect to its homogeneity and its agreement with previously specified values of the refractive index and dispersion are extremely high and difficult to meet; meanwhile the optical industry needs dozens and even hundreds of different grades of optical glass. Before the First World imperialist war, the production of optical glass was almost a monopoly of Germany. This caused a catastrophe in the optical equipment of the tsarist army. The final solution of the problem of producing optical glass came only in Soviet times and was the achievement of a number of people: D. S. Rozhdestvenskii, I. V. Grebenshchikov, A. A. Lebedev, A. I. Tudorovskii, N. N. Kachalov, and several others. However, the leading role in solving the problem was played by Dmitrii Sergeevich, and for this reason alone he must be regarded as one of the principal creators of the optical industry in the Union.

D. S.’s second great service was his initiative in the matter of creating the State Optical Institute, one of the first institutes founded by Soviet power. The entire plan of work of the Optical Institute was worked out by Dmitrii Sergeevich. He was likewise its organizer and the first director of the Optical Institute. The Institute was conceived broadly: it embraced all branches of scientific and applied optics and the applications of optics. D. S. regarded this breadth as a guarantee of the Institute’s success and of the productivity of its work. The Institute set itself, in the main, two goals: assistance in the development of the optical industry in the Union, and scientific work in the field of the infrared, visible, and ultraviolet parts of the spectrum. While giving priority to the first task, D. S. nevertheless considered it necessary that the Institute include at least a small but strong staff of workers in scientific optics.

The Institute was organized by Dmitrii Sergeevich very successfully. Beginning work in 1918 with 30 employees in 14 rooms of the University Physics Institute, D. S. handed over to the next director in 1932 four equipped buildings with a staff of about 200 scientific workers and with experimental workshops. If now the Soviet Union has its own optical-glass factories, its own computing bureaus, and large optical-mechanical plants, and is essentially free—

was freed from foreign dependence, then no small credit for this belongs to the State Optical Institute, and D. S.’s role as organizer of the entire Institute and as direct consultant on various technical questions was exceptional.

From January 1, 1939, Dmitrii Sergeevich again transferred the center of his activity to Leningrad University and to work in scientific optics.

1. Personal qualities of D. S. Rozhdestvenskii. As a person Dmitrii Sergeevich was unusually attractive: he was courageous, straightforward, intelligent and, in his essence, very responsive.

In his convictions he was always radical. At the establishment of Soviet power he greeted it with enthusiasm, immediately understood the broad possibilities that had opened before him and, as is evident from the foregoing, carried out several great undertakings which he never could have accomplished without Soviet power. He always called himself a Bolshevik and indeed was one, although he was not a member of the Party.

Outside the field of optics as well, D. S.’s interests were extremely broad; he worked seriously in the field of philosophy and in the field of botany and took a lively interest in contemporary life.

He treated his students warmly and cordially and was for them not only a teacher, but also a faithful friend. He inspired respect in everyone who had occasion to encounter him. All the more grievous is his loss. But he died leaving a bright memory. This memory of him will live as long as Soviet optics and the Soviet optical industry, Leningrad State University and the State Optical Institute exist.

CHRONOLOGICAL DATES

of the principal events in the life of D. S. Rozhdestvenskii

1929 (January 12) — elected a full member of the Academy of Sciences of the USSR.
1935 — enrolled, for special merits in the production of optical glass in the USSR, in the “Golden Fund” of the Optical Glass Plant in Leningrad.
1940 (June 25) — date of death.

LIST OF WORKS BY D. S. ROZHDESTVENSKY

1. Scientific investigations

A. Scientific investigations published in full or in excerpt

1. In the article by P. Drude, Optische Eigenschaften und Elektronentheorie, (Ann. Physik, (4) 14, 677—725 and 936—961, 1904), on p. 951, with the name of D. S. Rozhdestvensky indicated, are given experimental results and some conclusions from the work “Temperature coefficient of the optical properties of metals,” carried out by D. S. Rozhdestvensky in 1903 in Giessen, under Prof. Drude.

2. a. On the investigation of anomalous dispersion in sodium vapor, ZhRFKhO, physical section, 42, 87—97, 1910.

3. b. Zur Messung der anomalen Dispersion im Natrium Dampfe, Z. wiss. Photogr., 9, 37—47, 1910 (translation of No. 2, a).

4. a. Anomalous dispersion in sodium vapor, 93 pp. in quarto, St. Petersburg, 1912 (master’s dissertation).

5. b. Anomalous dispersion in sodium vapor, ZhRFKhO, physical section, 44, 395—430, 1912 (excerpt from No. 3, a).

6. c. Anomale Dispersion im Natrium Dampfe, Ann. Physik, (4) 39, 307—345, 1912 (excerpt from No. 3, a).

7. a. A. Afanassieff and D. Rozhdestvensky, Wood’s method for finding regularities in spectra, ZhRFKhO, 45, 346—354, 1913.

8. b. A. Afanassieff u. D. Roschdestwenskiy, Die Wood’sche Methode zur Auffindung von Gesetzmässigkeiten in Spektren, Phys. Z., 14, 780—783, 1913 (translation of No. 4, a).

9. a. Simple relations in the spectra of alkali metals, 105 pp., Petrograd, 1915 (doctoral dissertation).

10. b. D. S. Rogestvenskiy, Simple relations in the spectra of alcaline Metals, Trans. Opt. Inst. in Petrograd, 2, No. 13, 40 pp., 1921 (excerpt from No. 5, a).

11. a. D. S. Rozhdestvensky and V. I. Touroverov, Relation between the lines D₂ and D₁ of the sodium doublet, ZhRFKhO, physical section, 49, 128—137, 1918.

12. b. D. S. Rogestvenskiy, V. I. Touroweroff, Relation between the lines D₂ and D₁ of the sodium doublet, Trans. Opt. Inst. in Petrograd, 2, No. 14, 9 pp., 1921 (translation of No. 6, a).

13. On broad absorption bands, Proceedings of the Congress of Physicists, 1919, Protocols, ZhRFKhO, 51, 323—324, 1919.

14. The mercury spectrum, Proceedings of the Congress of Physicists, 1919, Protocols, ZhRFKhO, 51, 344—345, 1919.

15. On the homogeneity of optical glass, Proceedings of the Congress of Physicists, 1919, Protocols, ZhRFKhO, 51, 333—334, 1919.

16. Spectral analysis and the structure of the atom, Proceedings of the State Optical Institute, 1, issue 6, 87 pp., 1920.

17. Doublets in Spectral series, Nature, 107, 203—204, 1921.

18. D. S. Roschdestvenskiy, Das innere Magnetfeld des Atoms erzeugt die Dublette und Triplette der Spektralserien, Verh. Opt. Inst. in Petrograd, 20 pp., 1922 (excerpt from No. 10 with additions).

13, a. The significance of spectral series, Transactions of the State Optical Institute, 2, issue 7, 27 pp., 1921.
13, b. D. S. Roschdestvenskiy, Über die Deutung der Spektralserien, Verh. Opt. Inst. in Petrograd, 2, No. 7, 1921 (translation of No. 13, a).
14, a. Terms of high orders and the similarity between the spectra of one-electron and complex atoms, Transactions of the State Optical Institute, 2, 29—46, 1921.
14, b. D. S. Roschdestvenskiy, Terme hoher Ordnung und die Ähnlichkeit zwischen den Spektren einelektroniger und komplexer Atome, Verh. Opt. Inst. in Petrograd, 2, No. 8, 20, 1921.
15, a. Series of the spectrum of ionized magnesium from comparison with the spectrum of ionized helium, Transactions of the State Optical Institute, 2, 47—55, 1921.
15, b. The spectral series of ionised magnesium as compared with the spectrum of ionised helium, Trans. Opt. Inst. in Petrograd, 2, No. 9, 9 pp., 1921 (translation of No. 15, a).
16. Two independent systems of series in the spectrum of neon, Transactions of the State Optical Institute, 3, issue 18, 14 pp., 1924.
17. A note on optical glass, Transactions of the State Optical Institute, 8, issue 84, 22 pp., 1932.
18. On the resolving power of spectroscopes, Proceedings of the Academy of Sciences of the USSR, pp. 426—436, 1930; Transactions of the State Optical Institute, 8, issue 68, 1931.
19. A direct-vision prism for spectra of nebulae, Doklady of the Academy of Sciences of the USSR, pp. 11—14, 1933.
20. The evolution of the doctrine of the structure of atoms and molecules, Archive of the History of Science and Technology, 1, 1—20, 1933.
21. Anomalous dispersion in broad absorption bands, Proceedings of the Academy of Sciences of the USSR, pp. 35—51, 1934.
22. Interferometers for the study of anomalous dispersion, Proceedings of the Academy of Sciences of the USSR, pp. 1119—1151, 1934.
23. The periodic law of the elements on the basis of spectral analysis, Report at the Mendeleev Congress of 1934, Proceedings of the Congress, pp. 65—84, 1936.
24. Illumination of the microscope, Doklady of the Academy of Sciences of the USSR, physical series, 25, 115—118, 1939.
25. On the formation of images of transparent objects in the microscope (On the question of the imaging of transparent objects in microscopy), J. of Physics, 2, 323—346, 1940.
26. Coherent and incoherent rays in the formation of an image in the microscope, ZhETF, 10, 305—330, 1940.
27. D. S. Rozhdestvenskii and N. P. Penkin, Determination of oscillator strengths in the spectra of atoms (prepared for print), 1940.

B. Articles remaining in manuscript and unfinished

1. Works of the Atomic Commission of the State Optical Institute.
2. Requirements for an interferometer in measuring dispersions in a solid and calculation of the interferometer.
3. Influence of the resolving power of a spectrograph on anomalous dispersion and, chiefly, measurement of resolving power by means of sinusoidal lines.
4. Attempts at constructing a shortened objective of large aperture from elements.
5. On the resolving power of spectroscopes, part II.

2. Chapters and articles in large courses of physics and chemistry and editorial articles

1. Electromagnetic theory of light, Course of Physics by O. D. Khvolson, vol. V, pp. 437—554 (1923 edition), written in the spring of 1913.
2. Magneto-optics and electro-optics, Course of Physics by O. D. Khvolson, vol. V, pp. 554—597 (1923 edition), written in the autumn of 1913.

1. Spectral analysis, D. I. Mendeleev’s “Foundations of Chemistry”, vol. II, pp. 557—566 (9th edition), 1928.
2. Editor’s preface (containing a detailed characterization of R. W. Wood as a scientific worker) to R. W. Wood’s book Physical Optics, translated from English, pp. 5—13, 1936.
3. Editing of “Scientific Correspondence of the Academy of Sciences in the Eighteenth Century, 1766—1780,” Proceedings of the Archive of the Academy of Sciences, issue 2, 606 pp.
4. Editing of the Report on the Activities and Condition of Petrograd University for 1915, Petrograd, 330 pp., 1916.

3. Reviews and popular articles

1. Recent works on the optics of metals, ZhRFKhO, physical section, (II), 35, 61—65, 1903.
2. Quantitative determination of the anomalous dispersion of sodium vapor in the visible and ultraviolet parts of the spectrum, ZhRFKhO, physical section, (II), 36, 79—80, 1904.
3. The Doppler effect in the motion of matter, ZhRFKhO, physical section, (II), 38, 72—80, 1906.
4. Anomalous dispersion, ZhRFKhO, physical section, (II), 39, 101—110 and 117—136, 1907.
5. Dispersion and absorption of light in dielectrics, New Ideas in Physics, collection 5, SPB, pp. 55—110, 1912.
6. New works by R. W. Wood on fluorescence, ZhRFKhO, physical section, (II), 45, 163—172, 1913.
7. Rotation of the plane of polarization and double refraction in a magnetic field, ZhRFKhO, physical section, (II), 46, 71—91, 1914.
8. Scientific-research work in the optical industry, Opt.-Mech. Industry, No. 1, 6—12, 1931.
9. What the microscope has mastered and what it must conquer, Priroda, 25, 13—24, 1936; Opt.-Mech. Industry, No. 9, 3—9, 1936.
10. The fate of optics in the USSR, Collection for the 15th Anniversary of the State Optical Institute, L.—M., pp. 18—39, 1934.
11. Honorary Member of the Academy of Sciences of the USSR Orest Danilovich Khvolson. A brief word on the occasion of his death, Izv. Academy of Sciences of the USSR, No. 4, 477, 1935.

4. Speeches, lectures, and report notes of a fundamental character

1. Public lecture, November 23, 1912, “The Role of Electrons in Optics”; notes have not been preserved.
2. Lecture at the First Congress of Representatives of Physics, Chemistry, and Cosmography (December 1913)—“X-rays,” in the Proceedings of the Congress.
3. Opening address by the chairman at a meeting of the Physics Section of the RFKhO, January 12, 1916—“Review of the Problems of Spectroscopy,” ZhRFKhO, physical section, 48, 96, 1916.
4. “Optics in the Second Five-Year Plan,” Proceedings of the November Session of the Academy of Sciences, 1931, 2, 131—146, 1932; lecture in the spring of 1932 at the Educational Combine of Precision Mechanics and Optics on the same topic.
5. Report at the general seminar of the State Optical Institute, “Electron Diffraction” (spring 1932; manuscript preserved).
6. “On spectral analysis.” Report intended for reading in Alma-Ata in 1933 (manuscript preserved).
7. Speech at a session of the Academy of Sciences of the USSR on the report of A. F. Ioffe, March 15, 1936, separate brochure, pp. 3—8, 1936.
8. “Spectral and spectral analysis.” Report at a session of the Academy of Sciences of the USSR, March 15, 1936, the same brochure, pp. 9—39, 1936; also, as an article, Advances in Physical Sciences, 16, 897, 1936.
9. Report on the State Optical Institute at the Congress of Physicists, 1919, ZhRFKhO, physical series, 51, 319, 1919.

Unpublished memoranda of a fundamental nature

1. On the aims, tasks, and organization of the State Optical Institute. Several memoranda at various times.
2. On a physical encyclopedia, 1934.
3. On the study of rare earths, 1935.
4. On abstract and pure science (unfinished).

5. Minor notes and reviews

1. Polarization of X-rays, ZhRFKhO, physical section, (II), 35, 15—16, 1903.
2. Interference of light with a path difference of more than two million wavelengths, ibidem, 16, 1903.
3. Application of the phenomenon of interference in plane-parallel plates to the analysis of spectral lines, ibidem, 19, 1903.
4. A sensitive polariscope for spectral investigations, ibidem, 19—20, 1903.
5. A new kind of rays, ibidem, 20, 1903.
6. Report of the International Conference on electrical units of measurement, ibidem, 33, 1906.
7. Electrolytic production of very thin metallic filaments, ibidem, 48, 1906.
8. Note by D’Arsonval concerning a burner with an acetylene flame in oxygen, ibidem, 48, 1906.
9. On filaments resembling quartz filaments in their elastic properties, ibidem, 80, 1906.
10. Reproduction of diffraction gratings, ibidem, 201—202, 1906.
11. Spontaneous rotation of a mercury arc and rotation in a magnetic field, ZhRFKhO, physical section, (II), 43, 120, 1911.
12. On Stanley’s book Lines in the Arc Spectra of the Elements, ibidem, 389—390, 1911.
13. On Michelson’s book Light Waves and Their Applications, ZhRFKhO, physical section, (II), 44, 201—203, 1912.
14. On P. Zeeman’s book Researches in Magnetic Optics, ZhRFKhO, physical section, (II), 46, 30—33, 1914.
15. On R. Pohl’s book Physics of X-rays, ibidem, 33—34, 1914.