INSTITUTE FOR PHYSICAL PROBLEMS OF THE USSR ACADEMY OF SCIENCES

A. I. Shalnikov, Moscow

On December 28, 1934, by decree of the government, a new physics institute was founded within the system of the USSR Academy of Sciences, and P. L. Kapitsa was appointed its director. A site was chosen beyond the line of the ring railway on the Kaluga Highway, where in the spring of 1935 construction work was begun at an accelerated pace. According to the general plan, on a site of 2.2 ha, having the form of an isosceles right triangle, three separate buildings were erected: the laboratory building, residential houses for the institute staff and the director.

The institute began normal work after the government commission accepted all the construction and installation projects on February 25, 1937.

Fig. 1a. Basement premises

The institute’s laboratory building in its central part has two floors and a basement (Fig. 1). Adjoining the central part are a one-story wing of the large magnetic hall, as well as a wing of workshops and garages. This entire complex forms in plan, as it were, an unfinished letter “o,” with an inner asphalted courtyard. The institute’s laboratory rooms are located only on the first floor and in the basement of the central part of the building. On the second floor are the administrative section: the offices of the director and his deputy, the chancery, the accounts office, the “red corner,” a buffet, and also a lecture hall seating up to 100 people. In

in designing the building and arranging the work rooms, chief attention was paid to reducing to a minimum the inevitable general “shaking” of the building, which is a serious hindrance when working with sensitive suspended instruments. For these purposes, the foundation—

Fig. 1b. First floor

Visible labels in the plan: filter room; storeroom; car wash; carpentry workshop; darkroom; mechanical workshop; workshops; storeroom; corridor; garages; large hall; accumulator room; work room; oscillographic; library; vestibule; work rooms; photo room; coil room; laboratory assistants’ room; “gyroscope” room; small hall for laboratory assistants.

Fig. 1c. Second floor

Visible labels in the plan: red corner; party committee; conference room; terrace; buffet; meeting hall; director’s office; secretariat; deputy director’s office.

—ment, walls, and floors of the building were designed according to considerably increased standards. In addition, the laboratory building is located as far as possible from Kaluga Highway—a very busy thoroughfare, which is the main source of noise and shaking from passing automobiles, trams, etc.

Along the first and basement floors of the central part of the institute runs a corridor, on both sides of which are located work rooms. The corridor of the first floor ends with an [[unclear: word cut off at page bottom]].

into the machinery hall of the cryogenic laboratory. In addition to seven work rooms, on the first floor there are a standards room, a library, and also three darkrooms. In the basement, two of the five work rooms also have a special purpose: one of them is intended for spectral-analysis purposes, the other, protected by special baryte plaster, for X-ray investigations. For the needs of both these laboratories, one more (a fourth) darkroom has been equipped in the basement. All basement rooms are provided with special foundations. In contrast to the commonly used foundations, rigidly connected with the ground, the foundations of the institute’s basement may be called “floating.” These foundations are reinforced-concrete blocks of rectangular form, arranged flush with the floor surface, separated from the mass of the building by a wide gap; the blocks rest on rubber pads, which serve to damp possible vibrations. The institute’s basement foundations are designed in such a way that the vibration frequencies of the foundations along all three axes are identical, but differ for different foundations. The 7 foundations in the basement have the following vibration frequencies: 100, 200, 300, 400, and 500 vibrations per minute (500 vibrations per minute for 3 foundations). By selecting one foundation or another for the installation of sensitive instruments, it is thus possible to “isolate” these instruments from various kinds of periodic shaking that are unavoidable in any building (from motors, machine tools, etc.). It should be noted here that vibration damping by means of rubber pads was generally practiced widely in the institute. Without exception, all motors and machine tools are mounted on rubber cushions, either directly or on foundations similar to those installed in the basements and designed so that the natural period of vibration of the installation together with the concrete slab would be as far as possible from the resonant frequency of a given machine tool or unit. On such foundations are installed all compressors and motors in the machinery hall of the cryogenic laboratory, the large generator, and the greater part of the heavy machine tools in the mechanical and carpentry workshops.

The heating in the institute is central, hot-water heating. The boiler room and coal pit are located in the basement part of the main wing. In the future it is proposed to install special automatic regulators in those laboratories where a constant temperature is necessary. Ventilation of the rooms is forced, with warming of the incoming air. The rates of exchange are normal everywhere, with the exception of the glass-blowing workshop and the accumulator room, for the ventilation of which special powerful exhaust fans have been installed. All work rooms are supplied with water mains and drains and are equipped with deep, convenient faience washbasins with precisely adjustable taps. In some work rooms, gas water heaters for hot water of the “Fletcher” system have been installed. In addition, for the needs of the residential houses and shower rooms (there are four of them in the institute), a boiler is installed in the boiler room, supplying hot water daily in winter. Gas has been brought into all work rooms (2 burners per room)

and compressed air from two compressors—the main and the emergency one, installed in the boiler room. The compressors have a capacity of about 200 l per minute.

The windows in all working rooms are equipped with lowering shades, the design of which permits the transoms to be opened in winter and the windows in summer. A standard working room has an area of 30 to 40 m² and is illuminated by lamps enclosed in frosted globes.

Fig. 2. Machine hall. Direct-current generators and mercury rectifiers

Each switch, serving a section of two lamps, is fitted with an additional device that makes it possible to switch them from parallel connection to the mains to series connection. This makes it possible to create several levels of illumination in the working room.

Since the walls of the working rooms are solid (brick), in order to facilitate all kinds of temporary wiring (electricity, gas, water, etc.), vertical wooden strips about 10 cm wide and 2.5 cm thick are sewn onto them at intervals of 60–70 cm from one another. On the ceiling of each laboratory room, for the same purposes, two massive oak beams are fixed. In addition, for the installation of sensitive instruments, two brackets with massive oak tables measuring 50 × 80 cm are installed in each room at a height of 100 cm from the floor surface.

The floors in all laboratory rooms and workshops are parquet, rubbed with mineral oil. In some laboratories (where work with mercury is conducted) linoleum is laid over the parquet. The darkrooms, as a rule, are located between two laboratory rooms and have a common vestibule, which makes it possible to reduce to a minimum the possibility of light entering the darkroom. The entrance doors to the vestibule are closed by sliding curtains. In all darkrooms there are tables covered with linoleum, with a large number of drawers, as well as special latticed developing tables with direct drainage into a washbasin. The darkrooms are illuminated by Kodak fittings with replaceable reflected-light filters. The developing tables are equipped with Kodak lamps with a set of filters. The floors in the darkrooms are of Mettlach tiles.

The most labor-intensive object in the construction of the new institute proved to be the installation of the general electrical equipment. In order to supply the laboratory premises with all the necessary currents and to give the entire power-supply system maximum flexibility, taking into account the specific features of the institute, it was necessary to install a very complicated wiring system, for which several kilometers of various kinds of cable and multi-core hose wire were used. The institute’s power facilities are fed by two transformers with capacities of 320 and 100 kW (380 V with neutral), installed in a special transformer room. For lighting needs and small motor loads, a 100 kW transformer (220 V with neutral) is installed there as well. From the transformer room, current at a voltage of 380 V from the 320 kW transformer is led to an oil circuit breaker installed in the machine hall, and from the 100 kW transformer at 380 V—to a switchboard installed in the large magnet hall and serving to distribute alternating current among the working rooms. An additional cable connection made between the central switchboard of the large magnet hall and the distribution busbars of the starting devices in the machine hall makes it possible to supply the units of the machine hall from either of the two installed transformers. A connection has also been made to the central distribution board in the large magnet hall for current at 220 V with neutral. This arrangement makes it possible to supply the switchboards of the working rooms with alternating current at 380 and 220 V with neutral.

In the machine hall (Fig. 2) there are installed 4 motor-generators: No. 1—an asynchronous motor of 10 HP with a direct-current machine of 0–100 V, 7 kW; No. 2—an asynchronous motor of 23.4 HP with a direct-current machine of 220–300 V, 15 kW; No. 3—an asynchronous motor of 50 HP with a direct-current machine of 220–230 V, 33 kW; No. 4—an asynchronous motor of 20.4 HP with two direct-current machines of 150–220 V, 6 kW each. The machines are excited from a special storage battery of 228 V, with a capacity of about 130 A·h, which makes it possible to obtain great constancy of voltage. Another storage battery with a voltage of 172 V, divided into 23 sections, makes it possible, by means of a special switchboard, to—

supply to any laboratory room any voltage within the range from 2 to 172 V. For charging the storage-battery bank there is, in the machine hall, a mercury rectifier of 339 V, 35 A with 12 steps, starting from 15 V. Another mercury rectifier, 240 V, 120 A, installed there as well, serves to supply direct current to the laboratories \((-120\ \mathrm{V},\ 0,\ +120\ \mathrm{V})\). In addition, in the machine hall there is a small alternating-current machine with a frequency of up to 500 cycles. A trolley hoist with a lifting capacity of up to \(2.5\ t\) is brought into the machine hall from a separate side entrance.

A special distribution panel, located in the large magnet hall, to which the power leads and the leads of the field windings of four direct-current machines (6, 7, 15, 33 kW) are brought, makes it possible, by simple switching, to apply the voltage of any of these machines to any laboratory or to the adjacent control panels for the direct-current machines directly from the hall. In the first case, the voltage of the machine is regulated from the laboratory itself by means of a small potentiometer connected to the laboratory panel. This arrangement makes it possible to use, in the laboratory, direct current of many tens of amperes without employing bulky load rheostats. Thus the direct-current supply of the large magnets and motor-compressors of the machine hall of the cryogenic laboratory, which require constant regulation of the number of revolutions,

Fig. 3. Laboratory panel

is unusually simplified. The boards of the laboratory rooms (Fig. 3) are supplied with the following voltages: two terminals of alternating current at a voltage of 130 V (0 and phase from 220 V); four terminals 220 V with neutral or 380 V with neutral; four terminals from the distribution panel of the sectionalized storage battery; three terminals of direct current from the mercury rectifier (−120, 0, +120 V); two terminals from any of the direct-current machines and three additional terminals for regulating the excitation of the machine supplied to the laboratory board (for connecting a potentiometer).

In addition, from special low-voltage transformers operating from the lighting network, voltage has been brought into all laboratories to plug sockets (12 V voltage), which is very convenient for switching on low-voltage lamps for illuminating scales, microscopes, etc.

The Institute has a reliable grounding system covering a large part of the building perimeter. Under the ceiling in each workroom, a copper busbar is run around the entire perimeter of the walls and connected with the external grounding ring. All wiring to the laboratory boards and between the distribution board of the magnetic and machine hall is made with hose-type multi-strand wire enclosed in grounded iron pipes. Wiring from central, accurate impulse electric clocks, giving second signals, has been brought into all laboratories and darkrooms. By plugging electric stopwatches into the corresponding socket, one can obtain a very accurate time count. For less accurate time measurements, the laboratories are equipped with synchronous electric clocks connected to the common alternating-current lighting network.

The Institute has a local automatic telephone exchange for 25 numbers. The automatic telephone exchange is equipped with a special device which, by dialing a definite combination of digits on the dial, makes it possible to give a fire-alarm signal throughout the entire Institute. For fire-protection purposes, the Institute is also equipped with a pumping station for increasing the pressure in the Institute’s water-supply network in emergencies. In the most important parts of the building, emergency lighting wiring from storage batteries has also been installed.

The most responsible and important part in the installation of the Institute’s scientific equipment was the installation of the central distribution board, the large magnetic generator for obtaining superstrong magnetic fields in the large magnetic hall, and the apparatus for obtaining low temperatures in the machine hall of the cryogenic laboratory.

The large magnetic generator is located in the large magnetic hall (Fig. 4), directly adjoining the central part of the Institute. The hall is 28 m long and 6 m wide. The generator is installed at the end of the hall, as far as possible from the central part of the building. Through the middle of the hall runs a closed trench, in which are laid the cables supplying current to the coil located at the opposite end of the hall. Control of the generator is concentrated

on the central distribution board, located in the middle of the hall by one of the side walls. All the wiring from the laboratory boards, the storage battery, the mercury rectifiers, and the direct-current machines located in the machine hall also comes to this central board.

Fig. 4. Large magnet hall. Central distribution board and large magnetic generator

The institute’s central distribution board is assembled from separate panels. The first panel, with the main automatic circuit breaker, serves to distribute alternating current throughout the institute. The five adjacent panels control the direct-current machines in the machine hall and the motor of the large generator. Further, located here are: the storage-battery charging panel, the panel for switching direct-current machines to the laboratories, and the distribution panel of the sectionalized storage battery. The large generator, whose design was developed with the participation of P. L. Kapitsa, Prof. Uoker, and Prof. Kostenko, is a single-phase alternating-current machine, corresponding in its dimensions to a generator of 1,500 kW capacity, mounted together with an 80 HP direct-current motor on a massive cast-iron plate fastened to a reinforced concrete foundation standing on rubber cushions.

On the same plate there are mounted a specially designed automatic synchronous air circuit breaker, operated by a cam device connected by chain transmission with the axis of ro—

tor of the generator, as well as two small motors—one for driving the oil pump for cooling the generator bearings, the other for driving the compressor, which supplies compressed air at a pressure of 8 atm for extinguishing the arc arising at the moment the current is interrupted in the automatic air circuit breaker. To reduce the overvoltages that arise, a capacitor of 10 μF, 1000 V, connected in parallel with the automatic circuit breaker, is used. In series with the automatic circuit breaker there is also an oil switch, capable of breaking the circuit in the event of failure of the breaker. The generator motor is started from a direct-current machine according to the Leonard scheme, which makes it possible to achieve easy setting and regulation of a constant number of revolutions. The two excitation windings of the generator are supplied by two six-kilowatt direct-current machines installed (see above) in the machine hall.

The circuit breaker short-circuits the generator onto the coil at the moment when the voltage at the machine terminals is zero, and opens it after half a period, likewise when the voltage approaches zero. In order to carry out all these operations, at the required instant the breaker is controlled by the falling plate of a loop oscillograph installed in a separate room near the large magnet hall. The falling plate closes a number of contacts of various relays, which perform a series of operations bringing the automatic circuit breaker into “combat” readiness. Contact rings, rigidly connected with the generator shaft, carry out the final switching on of the release relay, which presses, by means of a strong spring, a roller against the pushing cam that switches on, and then switches off, the breaker. The current passing through the coil is fed to the oscillograph by means of a special shunt, where it is recorded on the falling photographic plate. The maximum power supplied to the coil during a short circuit of the generator is about 50,000 kW. During the short circuit, lasting about 0.01 sec., the generator rotor, making about 2000 revolutions per minute and weighing about 2.5 t, is braked by 10–15%. Under such abrupt braking the generator experiences a strong “blow,” which in the form of a shock spreads from the generator foundation in all directions. In order that this powerful jolt should not disturb the operation of the oscillograph or affect the accuracy of its recording, and also to protect the sensitive instruments located near the coil, the distance between the generator, on the one hand, and the coil and oscillograph, on the other, has been made so large that the sound wave of the “earthquake” arrives only after all observations of interest to the experimenter have already been made and recorded on the photographic plate. The maximum field that has so far been obtained by this method in a coil of special design reaches 325,000 gauss with a field volume of the order of several cubic centimeters. The limit to a further increase of the magnetic field is at present set by the strength of the coils, which, at the moment the current passes, undergo colossal electrodynamic loads, lying almost at the limit of mechani-

strength of the materials used. After each experiment the coil heats up by more than 100°.

The observer, who is in the oscillograph room, is connected by light and sound signaling with the observer operating the magnetic generator. During the experiments all doors to the large magnetic hall are locked automatically by electric locks.

This unique installation has already enabled P. L. Kapitsa to carry out a number of important investigations in the field of magnetism1. The difficulties of observing various kinds of effects over times on the order of 0.01 sec. proved only apparent. By using special recording instruments, it was possible to obtain observations in no way inferior in accuracy to those made when working with ordinary, long-existing magnetic fields. As an example one may cite the investigation of the Zeeman effect in strong magnetic fields, now being completed at the institute, which gives accuracies on the order of a percent.

There can be no doubt that with the aid of this installation many interesting investigations will be carried out in the future as well.

Another no less important part of the institute’s scientific equipment is the cryogenic laboratory. Here, too, original apparatus designed by P. L. Kapitsa has been installed.

As is known, liquefied hydrogen and helium are used to obtain low temperatures. However, the complexity of the corresponding apparatus greatly limits the number of laboratories possessing low temperatures. There are scarcely a few dozen such laboratories in the world. Moreover, most of these laboratories have very limited possibilities in terms of obtaining sufficient quantities of liquid hydrogen and helium. P. L. Kapitsa set himself the task of simplifying the corresponding apparatus and developing liquefiers that would make it possible to obtain liquid gases simply and in sufficient quantities.

The apparatus for obtaining liquid hydrogen and helium, installed in the machine hall of the cryogenic laboratory, fully satisfies these requirements. The process of obtaining liquid hydrogen on the institute’s installation is, in general outline, as follows. Chemically pure hydrogen from ordinary high-pressure cylinders is transferred into a steel cylinder of volume 0.7 m³, which serves as the main reservoir. From this steel cylinder the hydrogen is fed into an oil gas holder (volume 450 l), equipped with a device that makes it possible to maintain its float at a definite preset level. This device consists of mercury switches (actuated directly when the float of the gas holder rises or falls), which close the circuit of a relay that opens or closes the gas-supply valve, and also switches on or off a small motor-compressor

(with a capacity of \(4\ \mathrm{m}^3\) per hour), whose task is to pump hydrogen from the gas holder back into the cylinder. From the gas holder the hydrogen enters a compressor, which compresses it to \(175\ \mathit{atm}\) and then feeds it into the liquefaction apparatus. Having passed through the liquefaction apparatus, the hydrogen again enters the gas holder, and so on. In this way, chemically pure hydrogen is circulated in the system.

The liquefaction apparatus itself consists of a series of heat exchangers and an expansion chamber enclosed in a cylindrical vessel of red copper. For thermal insulation of the heat exchangers, the interior of this vessel is evacuated by an oil diffusion pump to a pressure of \(10^{-5}\)—\(10^{-6}\ \mathrm{mm\ Hg}\). For preliminary cooling (below the inversion point) of the hydrogen entering the liquefier, inside the liquefier there is a small tank into which liquid nitrogen is poured by siphon from a Dewar vessel. The nitrogen boils under reduced pressure, produced by an oil pump with a capacity of \(90\ \mathrm{m}^3\) per hour. In the expansion chamber the cooled hydrogen expands and is cooled to an even lower temperature, and, when passing through the heat exchangers, cools the incoming gas according to the counterflow principle. When a certain quantity of liquefied hydrogen (about \(200\ \mathrm{cm}^3\)) has accumulated in the reservoir of the liquefier, technical hydrogen, coming directly from high-pressure cylinders through a reducing valve, is passed through parallel tubes of the heat exchangers. This technical hydrogen is cooled to a temperature close to liquefaction, and then passes through a tube and a filter directly into the reservoir beneath the surface of the hydrogen already liquefied earlier. All impurities of the technical hydrogen thereby freeze out in the filter and do not enter the reservoir. Thus, for starting the apparatus chemically pure hydrogen is required, after which it liquefies technical hydrogen. The capacity of this apparatus is \(7\ \mathrm{l}\) per hour, which covers the entire need of the institute’s laboratories.

Hydrogen from the liquefier is drained through a special valve into an ordinary Dewar vessel, to the neck of which a tight lid with openings for the evaporating hydrogen is fastened by a rubber cuff. From this Dewar vessel, as needed, liquid hydrogen is transferred by siphon into the experimental apparatus. Usually, in all cryogenic laboratories, because of the great value of liquefied hydrogen, the gas evaporating from apparatus and Dewar vessels is led by a return line into the gas holder; since inexpensive technical hydrogen is liquefied in the institute, this operation need not be performed, and the evaporating gas may be released directly into the air. Nevertheless, the gas that usually evaporates is directed through a special lead line back to the cryogenic laboratory, where it is collected in the gas holder, from which it is then pumped by a small motor-compressor into a steel cylinder. In this way the supply of pure hydrogen is not only not consumed, but is even replenished.

The apparatus for liquefying helium (Fig. 5) in its general features does not differ in any way from that described above. The special features are the construc-

tion and principle of operation of the liquefier (see Uspekhi Fizicheskikh Nauk, 16, 145, 1936). The helium liquefier differs from the hydrogen one in that, in addition to the Joule–Thomson effect, adiabatic expansion of the gas with the performance of mechanical work is used for cooling the gas. For this purpose, a piston machine is mounted in the helium liquefier, operating at a temperature close to that of helium liquefaction. Part of the gas compressed to 30 atm, entering the liquefier and preliminarily cooled by liquid nitrogen boiling at reduced pressure, enters the cylinder of this machine and, instantaneously ex-

Fig. 5. Machine hall of the cryogenic laboratory. Installation for liquefying helium

panding (the machine is controlled by automatic valves), pushes the piston and the rod connected with it, at the other end of which there is a second piston, which ejects from the cylinder in which it moves a jet of water through a narrow opening. The other part of the gas passes through a reducing valve, where the pressure is lowered from 30 atm to 18 atm, and then, passing through an expansion valve, is led to the expansion chamber, which simultaneously performs the functions of a reservoir for liquid helium. The liquid gas accumulated as a result of the operation of the liquefier is then released as needed through a valve into the experimental apparatus. The gas evaporating from the experimental apparatus returns by a return line from the laboratory rooms into two intermediate gas holders, each with a volume of 250 l. Only after undergoing chemical purification is it fed into the main gas holder. The chemical purification of the returned helium o-

contamination is absolutely necessary, since these contaminants, having passed into the solid state, can immediately disrupt the operation of the expansion machine, which, as is known, operates without any lubrication. The returning gas is purified by passing it through activated charcoal, trained at high temperature under vacuum, cooled with liquid nitrogen. The rate of passage is 600 liters per hour.

The productivity of the institute’s helium liquefier is about 1.5 liters per hour. However, even this high productivity no longer satisfies the institute. At present P. L. Kapitsa has designed, and a new liquefier is being built, with a productivity of up to 6–7 liters per hour. With the construction of this liquefier the institute will have apparatus far more productive than other cryogenic laboratories.

For magnetic investigations the institute has a large Weiss-system magnet from the Erlikon firm, with pole pieces 160 mm in diameter. The electromagnet winding is tubular, cooled from the water-supply system. The magnet is mounted on a rotating table.

For spectral investigations (Zeeman effect, spectral analysis, etc.) the institute has three spectrographs: a Hilger spectrograph with quartz optics, model E-1; a GOI spectrograph with glass optics; and a universal Zeiss spectrograph with glass and quartz optics.

A Koch-system Kriuss microphotometer is used for measuring spectrograms.

In the institute’s standards room there are Sartorius microbalances, microbalances and analytical balances of Soviet manufacture, two metallographic microscopes made by Soviet factories, an optimeter for thickness measurements, binocular biological microscopes, comparators, etc.

For electrical measurements, the standards room has Winston bridges, Thomson bridges, Tinsley potentiometers, Disselhorst potentiometers, etc.

For X-ray investigations, in a basement room specially equipped for this purpose, a single-kenotron high-voltage installation manufactured by the Moscow X-ray Plant will be installed.

For vacuum melting of metals, a high-frequency installation manufactured by the Institute of Applied Physics (Leningrad), with a power of 1–2 kW, has been acquired.

The institute’s scientific storeroom has a large quantity of standard measuring apparatus and various kinds of materials and chemicals.

A very important part of the institute consists of excellently equipped workshops: glassblowing, mechanical, and carpentry.

The glassblowing workshop is designed for the work of three glassblowers. Large gas burners have been installed in it, and special piping made of wide tubes has been laid, making it possible to finish large glass instruments. The glassblowing workshop is supplied with compressed air from

institute compressors. There are also burners and equipment for making articles from quartz. Adjacent to the glass-blowing room is a preparation room, in which there are an apparatus for distilling water and mercury, a cathode-sputtering apparatus, an evacuation bench, annealing furnaces, etc. The glass-blowing room has a large assortment of tubes, various kinds of cylinders, and the like.

The mechanical workshop occupies an area of \(153\ \mathrm{m}^2\) and is equipped with both imported and Soviet machine tools. There are 7 lathes in the workshop, 2 milling machines (one of them a universal machine of the “Deckel” firm for precision work, supplied with a set of various accessories). There is also a shaper, 2 drilling machines, a surface-grinding machine, a tool-sharpening machine, a metal saw and shears. There are also 2 small watchmaker’s lathes and a small milling machine, as well as a machine for winding coils. The workshop has an extensive store of materials.

The carpentry workshop is equipped with a circular saw, a jointer, a thickness planer, and a wood lathe.

At present, a number of scientific works are already being carried out in the institute, which has at its disposal a very small staff. One of these works, already close to completion, is a thorough study of the Zeeman effect in fields up to 320,000 gauss, obtained with the aid of the large magnetic generator. It has been possible to show that, up to the maximum magnetic fields, there is good agreement between the measured splittings and those calculated theoretically, both for the Zeeman effect and for the Paschen–Back effect.

Another work, very complex experimentally, is devoted to measuring the gyromagnetic effect (the Einstein–de Haas effect) in superconductors, which will make it possible to draw a number of conclusions about the nature of the current carriers in the phenomenon of superconductivity.

The next work in the field of superconductivity consists in the investigation of superconductors obtained in the form of thin layers. From this it will apparently be possible to draw a number of conclusions useful both for understanding superconductivity itself and for the structure of thin metallic layers, which, as is known, possess a number of diverse anomalies.

The fourth work sets as its task the measurement of the viscosity of organic liquids at low temperatures in the region close to solidification. The method developed will later make it possible to carry out an investigation of the viscosity of the two modifications of liquid helium.

The institute’s further work will develop in the direction of cryomagnetic and cryoelectric investigations. It is intended to continue the work of P. L. Kapitsa on measuring the resistance of metals in a magnetic field, measuring the electrical resistance of very pure metallic crystals, etc.

Research will also be carried out toward developing methods for obtaining low temperatures, as well as toward improving methods for obtaining liquefied gases.

1. See Uspekhi fizicheskikh nauk, 11, 533, 1931. ↩