FROM THE HISTORY OF PHYSICS

NIKOLAI DMITRIEVICH PILCHIKOV

N. L. Polyakova and E. A. Popova-Kyandskaya

One of the talented Russian physicists of the late nineteenth and early twentieth centuries was Nikolai Dmitrievich Pilchikov. Although he did much for the development of Russian science, his works have not received sufficient attention.

The life and scientific activity of N. D. Pilchikov took place in the second half of the nineteenth century, a period marked by great changes in the state of our physical science. In this period there appeared a brilliant constellation of Russian scientists—D. I. Mendeleev, A. G. Stoletov, N. A. Umov, P. N. Lebedev, A. S. Popov, and others—who made an enormous contribution to the development of physics.

Nikolai Dmitrievich Pilchikov was born on May 9, 1857, in Poltava, into the family of a teacher of history and political economy.

In 1876, after graduating from the Poltava gymnasium, where he had shown the greatest liking for mathematics and physics, N. D. Pilchikov entered Kharkov University, in the physico-chemical division of the Faculty of Physics and Mathematics. At that time the Faculty of Physics and Mathematics of Kharkov University was renowned for such major figures as the professor of chemistry N. N. Beketov, the professor of mechanics V. G. Imshenetsky, the professor of geometry Andreev, and the excellent lecturer, professor of physics A. P. Shimkov.

While still a student, N. D. Pilchikov delivered scientific reports and began research work in the physics laboratory.

In 1880 N. D. Pilchikov successfully graduated from Kharkov University with the degree of candidate and, on the recommendation of Professor A. P. Shimkov, was retained to prepare for a professorship in the Department of Physics.

At Kharkov University N. D. Pilchikov worked until 1894, i.e., for 14 years, passing from assistant to extraordinary professor. He lectured on courses in experimental physics, meteorolo-

logy, various branches of theoretical physics, and conducted practical classes with students in physics and meteorology.

After eight years of work at Novorossiisk University in Odessa, N. D. Pilchikov returned again to Kharkov in 1902 and headed the Department of Physics of the Kharkov Technological Institute for six years.

N. D. Pilchikov.

On May 7, 1908, N. D. Pilchikov died.

N. D. Pilchikov was a scholar deeply devoted to science, with great erudition, initiative, and perseverance in his work. He carried out scientific research in the most diverse fields of physics, meteorology, and geophysics, combining experimental investigations in his works with their theoretical development. He devoted much attention to practical applications of physics and designed instruments. N. D. Pilchikov is credited with about fifty published scientific works, as well as a large number of scientific communications and reports published in the proceedings of various congresses and learned societies, review

NIKOLAI DMITRIEVICH PILCHIKOV

scientific articles, methodological works, and lecture courses on individual chapters of physics.

N. D. Pilchikov’s most valuable quality was a sense for the new in science. He closely followed the movement of scientific thought contemporary to him, responded vigorously to new physical discoveries and theories, and himself undertook research in the corresponding directions. This is evidenced by his work with X-rays, radioactivity, and radio engineering.

N. D. Pilchikov took an active part in the work of all the congresses (from the 7th to the 10th) of Russian natural scientists and physicians that convened during the period of his scientific activity. He also presented reports at international congresses on physics, electrical engineering, and meteorology.

N. D. belonged to the number of progressive Russian professors of his time. All his activity was directed toward the development of higher education in Russia, toward the development of existing scientific institutions and the creation of new ones.

At Kharkov University, thanks to N. D. Pilchikov’s persistent efforts, in 1891 a magnetic-meteorological division was founded at the Department of Physics, together with a meteorological station. This made it possible to improve the experimental base for teaching physics and meteorology and created minimal opportunities for conducting experimental work at the Department of Physics. N. D. Pilchikov partially assumed the expenses of creating the meteorological station himself. From 1892, N. D. Pilchikov, together with his students and assistants, began regular meteorological observations at the university meteorological station. The Main Physical Observatory included the station established by N. D. Pilchikov in the list of stations sending daily summaries to the observatory, gave a high assessment of the station’s work, and expressed gratitude to N. D. Pilchikov. Observations from the Kharkov University station were published in the observatory’s annals.

In the Society of Physico-Chemical Sciences at Kharkov University, on N. D. Pilchikov’s initiative, the Proceedings of the Society began to be printed.

At Novorossiisk University in Odessa, N. D. Pilchikov took an active part in the reconstruction of the physics cabinet and laboratory. Having received the support of such outstanding scholars as A. G. Stoletov, P. N. Lebedev, N. A. Umov, and a number of other prominent physicists, N. D. Pilchikov sought from the rector of Odessa University and the trustee of the Odessa educational district the implementation of his project for the construction of a good laboratory. As a result of his efforts, a separate measuring laboratory was created at Novorossiisk University.

In 1895–1896 N. D. Pilchikov worked to organize Higher Women’s Courses in Odessa.

In the Kharkov Technological Institute, N. D. Pilchikov secured the establishment of a printed organ of the institute—the Proceedings of the Kharkov Technological Institute—which began publication in 1903 and of which Nikolai Dmitrievich was editor for five years. Attaching enormous importance to the development of higher agricultural education in Russia, N. D. Pilchikov was one of the initiators of the organization of an agronomic department at the Kharkov Technological Institute.

The progressive views of N. D. Pilchikov were well known and were valued by the foremost scientists of Russia. In 1901 P. N. Lebedev addressed a letter to Nikolai Dmitrievich in which he set forth a project for uniting Russian physicists in a single general Russian physical society with its own scientific journal. P. N. Lebedev appealed to N. D. Pilchikov for support and practical assistance in carrying out the undertaking he had conceived. N. D. Pilchikov responded warmly. However, P. N. Lebedev did not succeed in realizing his project. Progressive Russian physicists encountered, as P. N. Lebedev noted with bitterness in one of his letters to Nikolai Dmitrievich, much “that has no relation to physics, but impedes it.”

N. D. Pilchikov was an excellent lecturer; his audiences were always numerous. In addition to the required lectures, he often gave students lectures on new achievements in science. Nikolai Dmitrievich devoted much time to consultations with students, delved into the conditions of students’ lives, and helped them materially.

In various cities of southern Russia N. D. Pilchikov gave public lectures, accessible to the broadest circle of listeners, on the most urgent scientific topics.

He deeply understood the role of Russian scientists in the development of physics and spoke of them in his lectures. Thus, in the introductory part of one of his lectures he says: “... In the line of glorious names of scientists who, by their selfless love of knowledge, of truth, and of labor, laid the cornerstones—so rich in scientific and practical consequences—of the doctrine of radiant energy, we have already mentioned the glorious Russian name of Professor Lebedev, the pride and honor of Moscow University. Let us also recall the first Russian scientist who, a century and a half ago, worked on deciphering radiant phenomena—our great naturalist, Academician Lomonosov...”

Nikolai Dmitrievich Pilchikov stood among those professors who advocated the autonomy of higher education in Russia, against the institution of hired informers spying on advanced students and professors in higher educational institutions, and against repressions directed at students and professors. N. D. Pilchikov considered closer cooperation between professors and students necessary.

During his work at the Kharkov Technological Institute (1902–1908), the well-known reactionary physicist N. N. Shiller, who was then director of the institute, responded to student unrest and speeches by the progressive professorial staff with harsh repressions. He caused particularly great damage at the institute in 1904, placing many students under arrest and dismissing many professors.

N. D. Pilchikov, at meetings of the educational committee and in the press, spoke out in defense of the students and insisted on the return of the professors.

The attitude of the progressive part of the student body toward N. D. Pilchikov can be seen, in particular, from the obituary “In Memory of Prof. N. D. Pilchikov,” published in the newspaper Utro on May 8, 1908, signed by the student R—m:

“Recalling the life of the late professor N. D. Pilchikov, one cannot remain silent about that sensitive responsiveness which the deceased displayed toward the student body.

The memory of the late professor will remain for his listeners for their whole lives gratifying, dear, and bright.

From the very beginning of his tenure as professor at the Kharkov Technological Institute, Nikolai Dmitrievich succeeded in winning the universal sympathy of the student body, to whom he more than once rendered enormous services.

Being one of the most active members of the educational committee after the memorable Shiller devastation, Nikolai Dmitrievich played an outstanding role in facilitating the return of the dismissed professors. For nearly an entire year he raised this question in the columns of the press, at meetings of the educational committee and, finally, while at the congress of representatives of higher educational institutions in Petersburg, drew attention in the Ministry of Public Education to the necessity of returning the dismissed professors. This question greatly agitated the student circles at that time, and it may be said with certainty that its positive resolution, to which the late professor once again contributed chiefly, influenced the further peaceful course of academic life in our Institute. After this, sympathy for the late professor became even more deeply rooted among the student body. Whatever question arose in the academic life of the institute, the resolution of which was desirable for the students, the latter considered it their first duty to turn for advice and support to Nikolai Dmitrievich. All the lofty and noble impulses of youth were very close to the late professor, and he always went to meet their wishes.

One involuntarily recalls the lively participation which the respected professor took in the fate of the students arrested after the well-known incident with Professor V. A. Albiiitsky—members of the cen-

...of the central body. One of the arrested students, Likhonin, was ill with tuberculosis. Being in prison was disastrous for him. Nikolai Dmitrievich immediately paid the required bail in the amount of 1000 rubles, and Likhonin was released. The late professor showed the same lively interest throughout this entire trial.

At meetings of the academic committee, Nikolai Dmitrievich always cast his vote in defense of the students’ interests.

The late professor responded with particular sympathy to the material needs of the students, for whose benefit he repeatedly made donations, arranged lectures, etc. ...”

“... Nikolai Dmitrievich never confined himself to the narrow limits of the prescribed teaching program and opened broader horizons before his listeners. He organized extracurricular evening lectures, where he acquainted students with new trends and discoveries in the field of physics...”.

“... In conclusion one may say that, while science has lost in Nikolai Dmitrievich an outstanding European scholar, the student body of the Kharkov Technological Institute has, in addition, lost in the deceased an extremely sensitive, kind, humane person and friend.”

Let us proceed to consider the most important directions of N. D. Pilchikov’s scientific investigations.

Works on terrestrial magnetism. In the second half of the nineteenth century, a number of studies of terrestrial magnetism, in particular of magnetic anomalies, were undertaken in Russia.

In 1874 I. N. Smirnov discovered the Kursk magnetic anomaly. He succeeded in detecting two points—in Kustarnaya and Belgorod.

Nine years later the Russian Geographical Society decided to verify the anomalies in the Kursk–Kharkov region.

In 1883, with funds from Kharkov University and on commission from the Russian Geographical Society, N. D. Pilchikov undertook investigations in the region of the Kursk magnetic anomaly. He did not confine himself to checking I. N. Smirnov’s observations, but, proceeding from an analysis of the anomalies discovered before him in Belgorod and Kustarnaya, assumed their presence at a number of other points as well, and indeed discovered major anomalies in Maryino and Prokhorovka. Comparison with I. N. Smirnov’s observations made it possible to determine the secular variations of the magnetic elements in Kharkov, Belgorod, and Kustarnaya. At the end of his work N. D. Pilchikov confidently indicated that the magnetic anomalies are caused by deposits of iron ore, the dimensions and depth of occurrence of which can be determined by further, detailed magnetic surveys. Let us note that the correct views on the nature of the Kursk magnetic anomaly not only in N. D. Pilchikov’s time, but much...

later were far from generally accepted. N. D. Pilchikov believed that the theoretical interest and practical importance of further investigations of the Kursk magnetic anomaly were beyond doubt. Lack of funds and the absence of suitable instruments deprived N. D. Pilchikov of the possibility of continuing the work he had begun.

For this work, published in the Proceedings of the Russian Geographical Society, N. D. Pilchikov received from it a silver medal. The research material served as the basis of his master’s dissertation, “Materials on the Question of Local Anomalies of Terrestrial Magnetism.”

After N. D. Pilchikov, work on the magnetic anomaly of the Kursk–Kharkov region was carried out by individual scientists; a fundamental investigation of this region was conducted by Professor E. E. Leist of Moscow University. It lasted 18 years.

N. D. Pilchikov’s interest in the problem of the Kursk magnetic anomaly did not fade. In 1898, at the 10th Congress of Naturalists and Physicians, N. D. Pilchikov demonstrated a magnetogram obtained in the temporary observatory he had set up near the village of Kochetovka (Kursk Governorate). At the same time he supported E. E. Leist on the question of the nature of the magnetic anomaly and insisted on the necessity of organizing deep drilling and conducting studies of the influence of physical conditions, chiefly pressure and temperature, on the rocks extracted.

Work on terrestrial magnetism attracted N. D. Pilchikov’s attention for a number of years. He published several articles on this question and delivered reports in learned societies and at congresses. In doing so, he was engaged not only in magnetic measurements, but also in the theory of magnetic anomalies, and in the design and improvement of magnetic instruments.

N. D. Pilchikov drew his pupils, students of Kharkov University, into his research on terrestrial magnetism.

Work in electrochemistry. From 1887, for several years N. D. Pilchikov experimentally investigated various physical and chemical phenomena occurring during electrolysis. He studied in detail the initial phase of electrolysis, the influence of the surface of electrodes on the process of metal deposition, electrocapillary phenomena, and so on. In this work he was apparently one of the first to apply a method consisting of a combination of optical and galvanometric methods, with the help of which the process of electrolysis was studied. N. D. attempted to explain the phenomena occurring in the process of electrolysis on the basis of the then still little-known thermodynamic works of Gibbs. The results of N. D. Pilchikov’s experimental investigations are set forth in five articles published in the Comptes rendus of the French—

of the Academy of Sciences. An attempt at their theoretical substantiation was given in the extensive work “Materials on the question of applying the thermodynamic potential to the study of electrochemical mechanics.” This was one of the first works in Russia on the thermodynamics of processes in electrolytes.

It is interesting to note that in the introductory chapter of the above-mentioned book, setting forth the general principles from which he proceeds, and touching on the question then under discussion of the possibility of regarding particles of matter as vortices in the ether and the question of the materiality of the ether, N. D. Pilchikov wrote: “Perhaps ‘matter’ is not ‘ether,’ but ether cannot but be matter.”

Works on atmospheric optics. In 1809, when Arago discovered the polarization of light scattered by the atmosphere, a detailed study began of this phenomenon, which was closely connected with the question of the origin of the blue color of the sky. Attempts to explain the blue color of the sky, and then also the phenomenon of polarization of light scattered by the atmosphere, did not for a long time lead to positive results. Brücke’s experiments (1853) on the passage of light through colloidal solutions and, in particular, Tyndall’s investigations (1869), which showed that light scattered in a turbid medium in a direction perpendicular to the incident beam is polarized, provided an experimental basis for Rayleigh’s theory of light scattering.

In 1871 Rayleigh’s first work appeared, in which he considered the scattering of light in a medium in the presence of small particles and put forward the suggestion that the blue color of the sky is the result of the scattering of sunlight by particles suspended in the atmosphere. Rayleigh also almost completely explained the course of polarization across the sky, discovered by Arago and others.

Although the formula obtained by Rayleigh for the scattering of light was correct, the initial premises of his theory of the scattering of light by the atmosphere were erroneous and could not eliminate a number of other explanations of the color of the sky then in existence. In connection with this, a large number of works were undertaken to verify the correctness of various theories. In particular, according to Lallemand, the blue color of the sky was considered to be due to fluorescence caused by the absorption of ultraviolet rays by the atmosphere.

In April 1892, at the meteorological station of Kharkov University, N. D. Pilchikov for the first time made observations through light filters of the spectral polarization of light scattered by the atmosphere, with the aim of finding a new argument for or against Lallemand’s hypothesis. N. D. Pilchikov proceeded from the following considerations. The light of fluorescence is not polarized. Therefore, in determining the degree of polarization of light in the atmosphere through a blue and then through a red filter, it would follow, if Lallemand’s hypothesis were correct, to find in the first case—

where the degree of polarization is smaller than in the second. However, observations gave the opposite result. N. D. Pilchikov established that at the points of greatest polarization, i.e., at an angle of 90° from the sun, the degree of polarization in blue rays is greater than in red ones. By this N. D. Pilchikov experimentally proved the incorrectness of the assumption that the blue color of the sky is due to the fluorescence of the air. His observations were in agreement with Rayleigh’s theory.

In 1899 Rayleigh gave a new explanation of the blue color of the sky, proceeding in his theory from the fact that the scattering of light is caused by the molecules of the air and that there is no need to assume the presence of foreign particles in the atmosphere.

Continuing the study of the polarization of the atmosphere, N. D. Pilchikov investigated the dependence of the difference in the degree of polarization in blue and red rays on various meteorological conditions, i.e., on the degree of turbidity of the atmosphere. In particular, N. D. Pilchikov studied this difference under different winds, in winter and summer conditions, and with different amounts of dust in the atmosphere. He established a number of facts; in particular, he found that with an increase in turbidity the total polarization decreases, and for blue rays much more rapidly than for red ones. These data agree with the results of Pertner’s later experiments (1901) on the dispersion of polarization in turbid media.

N. D. Pilchikov, for the first time after Cornu (1889), carried out a detailed investigation of the polarization of moonlight scattered by the atmosphere. By observations made at Kharkov University, he showed that the degree of polarization of the light sent by the night sky continuously decreases from the full moon, where it is maximal, to the new moon, where it is equal to zero, and then again increases up to the full moon.

Making observations during a total solar eclipse, N. D. Pilchikov established that the polarization of light at the points of maximum polarization completely disappears during the total phase of the eclipse. He himself explained the facts he had discovered by the fact that during a solar eclipse the weak but strongly polarized light entering the polarimeter from the lunar shadow cone illuminated by the corona cannot be observed against the background of the strong but weakly polarized light arising as a result of diffusion of light from the atmosphere, illuminated by the Sun, into the lunar shadow cone. N. D. Pilchikov confirmed his explanation by simple and ingenious experiments reproducing, under laboratory conditions, observations during a solar eclipse.

N. D. Pilchikov was thus one of the pioneers in the study of the polarization of light scattered by the earth’s atmosphere.

Work on X-rays. As soon as reports appeared of Roentgen’s discovery, and long before the appearance of

of detailed articles about these experiments, N. D. Pilchikov, with his characteristic sense for what was new in science, began the study of X-rays.

He published the results of his experiments in the Proceedings of the Paris Academy of Sciences for 1896. They were also described by a collaborator of his laboratory, I. Todchidlowski, and by V. Gernet in the Bulletin of Experimental Physics and Elementary Mathematics in the same year.

To obtain X-rays, N. D. used a tube in which, in addition to the anode and cathode, he placed in the path of the cathode beam a mica plate coated with zinc sulfide. With the aid of this tube he succeeded in obtaining a more powerful beam of X-rays than that obtained with the Crookes tube, and in reducing the exposure from 20–30 minutes to 2 seconds.

In 1898, in the article “Radium and Its Rays,” speaking of the production of X-rays, N. D. wrote: “Focus tubes are those X-ray tubes in which, in the path of the rays proceeding from a concave cathode, at its focus, some solid body is placed; upon striking it, the cathode rays excite X-rays. Focus tubes give far more X-rays than ordinary Crookes tubes. They were proposed by us (1896) and, with certain modifications, have come into general use.”

Already in his first experiments N. D. Pilchikov showed that an electrostatic field has no effect on X-rays. This is how these experiments are described by I. Todchidlowski: “... To prove the absence of action on these rays by bodies charged with electricity, the following experiment was made (January 22)* : on a photographic plate, wrapped in completely opaque black paper, two thick copper wires insulated with glass were placed. Half of the plate, together with the wires lying on it, was covered by a thick copper sheet, and a stream of X-rays was directed onto it. After 10 minutes the wires were connected to the terminals of an electrophore machine; the covering copper plate was moved to the half previously exposed to the X-rays; the X-rays were allowed to act again for 10 minutes, and after development it was found that bodies charged with electricity do not act on X-rays (because in the photograph the second halves of the photographed wires constitute a strict continuation of the first), i.e., these rays do not have the character of the already known phenomenon of convective discharges of electricity.”

N. D. Pilchikov also showed, somewhat later than Roentgen but independently of him, that X-rays are not deflected by a magnetic field. From these experiments N. D. drew an entirely correct conclusion. This is how V. Gernet sets it forth, describing

*) 1896.

In 1896, Pilchikov’s experiments in the note “Do X-rays represent a stream of charged material particles?” He writes: “... What, then, do X-rays represent? Professor Pilchikov inclines to the supposition that X-rays are transverse vibrations of the ether with extremely short waves, so short that polished surfaces, which reflect ordinary light, are as if matte for X-rays and scatter them.”

N. D. Pilchikov also studied ionization by X-rays and their absorption in various media.

From what has been said above it is clear that N. D. Pilchikov was one of the pioneers of radiography in Russia.

It should be pointed out that he was also one of the pioneers of roentgenology in Russia. Already in 1896 he assisted physicians in the practical implementation of X-ray diagnostics, devoting much time to making X-ray photographs for patients who turned to him for help.

An ardent popularizer of science, N. D. Pilchikov at the very beginning of 1896 delivered a series of public lectures on X-rays (in Odessa, Kishinev, Kherson, and Nikolaev; the proceeds from all the lectures went to the future Higher Women’s Courses in Odessa) and three times demonstrated experiments in learned societies. A report at a joint meeting of the societies of naturalists and physicians drew an audience of a thousand people into the cramped assembly hall of the university.

Works in radio engineering. On May 7, 1895, A. S. Popov, at a meeting of the Russian Physico-Chemical Society, demonstrated his famous “thunderstorm indicator.” This day entered the history of science as the day of the discovery of radio. In 1896, at meetings of the same Physico-Chemical Society, the first radiogram was transmitted. From that same year date the works of A. S. Popov for the Russian navy on signaling over long distances.

N. D. Pilchikov responded warmly to A. S. Popov’s invention and set about developing it. At that time he was working in Odessa at Novorossiisk University.

On March 23, 1898, N. D. Pilchikov delivered a lecture at which he demonstrated new experiments in radio: a clock running under the action of radio waves, a radio semaphore, and a radio beacon. A. S. Popov had pointed out the possibility of carrying out such experiments as early as 1897.

On November 12, 1898, the newspaper Odesskii listok published a report on the lecture delivered by Professor N. D. Pilchikov. In this lecture he pointed to the priority of A. S. Popov in the invention of radio, thereby joining the scientific community that upheld the priority of A. S. Popov. In his lecture N. D. Pilchikov also reported that he had developed an instrument

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providing such transmission of radiotelegrams in which they could be received by no one except the addressee.

On December 12, 1898, N. D. Pilchikov addressed a letter to the Minister of War with a proposal for the use of radio in naval affairs. The proposal stated that, on the basis of the laboratory experiments he had carried out, it was possible: “... 1. to establish telegraphic wireless communication between separate parts of an army, on the condition that the enemy cannot either interfere with such communication or read the telegram; 2. to explode planted mines at a considerable distance, without having any communication with them by cable or wire, which the enemy could easily discover and cut; 3. to create such mine boats which, having on board not a single person of the crew, could move, steer, overtake enemy armored vessels and sink them; 4. to construct such land mine-carriers which, likewise having on board not a single person of the crew, could move ahead of the attackers and destroy the fortifications encountered.”

On January 26, 1899, in reply to an inquiry from the chief head of engineers of the Naval Ministry concerning the essence of his inventions, N. D. Pilchikov wrote that, while A. S. Popov and Marconi strove to attain as great a distance as possible over which signals could be transmitted, “... I developed the question of how to isolate the wireless electrical transmission of energy between two points from the disturbances caused by the action of electric waves of extraneous origin.” And further, “... After fairly prolonged theoretical and experimental investigations I settled on the idea that an instrument receiving the action of electric waves must necessarily be supplied with a special protective projectile—protector—which, filtering the electric waves reaching it, would give access to the operating mechanism only to those waves which had been sent by us. Several such protectors, differing from one another according to their purpose, have been devised by me.” Further, N. D. Pilchikov sets forth the aims that will be achieved by a protector for wireless telegraphy, indicating at the same time that his instruments operate with two pens and are connected with an alphabet distinct from the Morse alphabet; by a protector for mines; by a protector for a wireless electric rudder, indicating that the rudder must be provided with two mechanisms, one turning to the left, the other to the right, and these two mechanisms can be set in action by two different systems of electric waves; by a protector for the wireless rudders of mine land automobiles; by a protector for railway, port, and other semaphores, beacons, and so forth. In this same letter N. D. Pilchikov asks the War Minis—

...of material and technical assistance for ordering instruments and conducting experiments.

Almost a year later N. D. Pilchikov again applied to the War Ministry and, on January 26, 1901, wrote in a memorandum to the Main Engineering Administration: “... numerous experiments must be carried out under the most varied conditions of naval and land telegraph military service, in order to choose, from among the laboratory solutions found for the questions, that solution which will prove most practical for work over great distances.” Here N. D. Pilchikov once more noted that “... the essence of my method of wireless telegraphy consists in the fact that the transmitting and receiving apparatuses are tuned in unison, and the motor parts of the receiver (for example, the telegraph, the mine igniter, the rudder of a submarine mine or of a teleautomotor boat, and so forth) are constructed in such a way as to come into action exclusively under the impact of unison waves.”

In May 1901 the matter of N. D. Pilchikov’s invention was transferred to the Naval Ministry, which in June 1901 appointed a commission to examine N. D. Pilchikov’s apparatus on site. The commission included Professor A. S. Popov. This trip did not take place; however, on the basis of N. D. Pilchikov’s memorandum, Professor A. S. Popov on October 28, 1901, gave a review of his proposal. He wrote:

“In Professor N. D. Pilchikov’s proposal, attention is merited by the posing of the question of protection against the interception of dispatches of the wireless telegraph by means of the use of a telegraphic apparatus writing with two pens, and of a special alphabet instead of Morse. The use of electrical resonance, however, does not fully protect against interception of dispatches and is employed by all who use wireless telegraphy at the present time. The question remains open of the range of telegraphing by the proposed apparatuses and of the degree of technical development of the instruments themselves. It is desirable that Professor N. D. Pilchikov specify quite precisely the features of the instruments personally invented by him, as distinguished from other systems of instruments making use of electromagnetic waves and electrical resonance, so that, when inspecting Professor Pilchikov’s apparatuses, no inconvenience might arise owing to possible coincidences in the layout schemes of the instruments with those used on the ships of the fleet and being continuously developed in the telegraphy workshop at Kronstadt.”

On January 2, 1902, having arrived in Petersburg for the 11th Congress of Naturalists and Physicians, N. D. Pilchikov visited the mine section of the Naval Technical Committee, to which he gave oral explanations on the question of his inventions.

After this, the Chief of the Main Naval Staff, in his letter of March 2, 1902, to the Chief Inspector of Engineers, wrote: “... The Head of the Naval Ministry, upon a report to him by the Naval Technical Committee, having become acquainted with the lightning protector invented by Professor Pilchikov of Novorossiisk University for wireless telegraphy, and with the merits of this invention, agreed to take part in half of the expenses caused by the preparation and production of the first experiments with the protector, for which Professor Pilchikov is asking 5,000 rubles...”

Only at the end of the summer of 1902 were N. D. Pilchikov’s requests satisfied for the allocation of funds, accumulators, and a vessel of the Black Sea Fleet for conducting the tests.

In connection with N. D. Pilchikov’s move in August 1902 to Kharkov, where he began work at the Technological Institute, the experiments on the Black Sea were carried out only in the summer of 1903. For this purpose he built one wireless-telegraph station at the Khersones lighthouse (near Sevastopol), and the other on the warship Dnestr, placed at N. D. Pilchikov’s disposal for his experiments. The results he obtained led to an increase in the distance of radio transmission by at least a factor of three compared with the former one.

The subsequent fate of these experiments is still unknown. It is known only that the commander of the Russian fleet in the Pacific Ocean, on September 1, 1904, expressed gratitude to N. D. Pilchikov for his labors for the benefit of the Pacific Fleet.

At the Kharkov Technological Institute, N. D. Pilchikov continued his investigations in radio communication. At his own expense he built on the Institute grounds a radio station with a mast 25 m high and a pavilion for experiments in wireless telegraphy. N. D. Pilchikov installed the mobile station on an automobile, which he had also purchased at his own expense. The continuation of this work met with an obstacle in the person of the director of the Technological Institute, Shiller, who forbade N. D. Pilchikov to drive an automobile on the Institute grounds.

During this period N. D. Pilchikov corresponded with A. S. Popov. In his letter of October 22, 1904, A. S. Popov informed N. D. Pilchikov that he had sent him, at his request, a relay.

Thus, the materials known to us at the present time indicate that N. D. Pilchikov was one of the pioneers in the field of radio. He proposed a model of a “protector” device for combating interference from extraneous radio stations. As early as 1898, N. D. Pilchikov was developing mechanisms controlled by radio, thereby raising the problem of remote control by radio.

Such are the main directions of N. D. Pilchikov’s work. In addition, he is credited with a considerable number of studies in optics, meteorology, radioactivity, physical chemistry, and a number of designs of original instruments (refractometer, spectropolarimeter, seismograph, etc.).

An outstanding, versatile scientist and an excellent teacher, N. D. Pilchikov entered the history of Russian science, to which he devoted his entire life.

LIST

OF THE PRINCIPAL PRINTED WORKS OF N. D. PILCHIKOV

Optics

1. Determination of the refractive index of liquids by means of liquid lenses, ZhRFKhO, phys. section, 1, 13, 393 (1881).
2. Refractomètre à lentille for determining the refractive index of liquids and readily fusible bodies, Journ. d. Phys., series 2, 8, 416 (1889).
3. On the polarization of the lunar-light atmosphere, Comptes Rendus, 114, 468 (1892).
4. On the spectral polarization of the sky, Comptes Rendus, 115, 565 (1892).
5. On the polarization of the sky during a solar eclipse, Comptes Rendus, 141, 472 (1905).
6. On the polarization of the sky during a solar eclipse, Comptes Rendus, 142, 1449 (1906).
7. Polarization of diffused light, ZhRFKhO, phys. section, 1, 40, 165 (1908).
8. On a mirror method for measuring angular variations. Journ. d. Phys., series 2, 8, 330 (1889).
9. Observations on the polarization of the sky in Huygheime, Izvestiya of the Technological Institute, 2, 1 (1906).

Electricity

1. On the initial phase of electrolysis, Comptes Rendus, 108, 614 (1889).
2. On electrolytic polarization by metals, Comptes Rendus, 108, 898 (1889).
3. On the electromotive force of contact, Comptes Rendus, 109, 105 (1889).
4. On changes in current intensity during electrolysis, Comptes Rendus, 109, 135 (1889).
5. A new method for studying electrical convection in a gas, Comptes Rendus, 118, 631 (1894).
6. Materials on the question of applying thermodynamic potential to the study of electrochemical mechanics, 1896, monograph, 158 pp.
7. Photogalvanography, Elektrotechn. Zeitsch. 17, 384 (1896).

Terrestrial Magnetism

1. Magnetic observations between Kharkov and Kursk in 1883, Izvestiya of the Russk. Geogr. Society, 19 (1883).
2. Materials on the question of local anomalies of terrestrial magnetism. Master’s dissertation, 1888, 154 pp. + 61 drawings.
3. The influence of magnetic anomalies on the diurnal and annual course of magnetic elements, Meteorological Herald, 443 (1898).
4. On the theory of magnetic anomalies, Journ. d. Phys., series 2, 7, 437 (1888).

Meteorology

1. On investigations of the upper layers of the atmosphere, Meteorol. Vestn., 109 (1893).
2. Results of observations made at the meteorological station of Kharkov University, 1892–1893. Zap. Khark. Univ., No. 3, 23; No. 4, 273 (1893).
3. On the position of the minimum in the daily course of air temperature, Meteorol. Vestn., 69 (1893).
4. New photographs of lightning, Comptes Rendus, 121, 250 (1895), 134, 158 (1902).

X-rays

1. On the emission of X-rays by a tube containing a fluorescing substance, Comptes Rendus, 122, 461 (1896).
2. On X-rays, Comptes Rendus, 122, 723 (1896).
3. The action of X-rays on double and triple electric layers, Comptes Rendus, 122, 839 (1896).

* *
*

1. A generalization of the Gay-Lussac method for determining the capillarity constant of liquids, ZhRFKhO, Phys. section, pt. 1, 20, 83 (1888).
2. Radium and its rays, Vestn. op. fiz. i el. mat., 25, 3 (1901).