Vol 8

This article contains a description of the complex of geodetic and mine surveying works on the creation of a network of trigonometric and polygonometric principal points in the area of the Berezovskoe field and in transferring the topographic survey. The Berezovskoye field, with its administrative center as part of the Berezovsky Combine, is located 12 km northeast of Sverdlovsk in a forested area lying along the Pyshma River. The gold deposits are part of the beresites, which are particularly water-bearing. This caused great difficulties in coordinating the shaft surveys and selecting the type of underground stations. The enclosed area required a very complex connecting network and the construction of high signals. Parallel to the construction of the network, preparatory work was carried out on the compilation of a general plan of the deposits with mining-geometric analysis; this work consisted of studying archives and incorporating the network of old points into the new network.

None of the problems of the geology of Central Asia, both theoretical and deeply practical (metallogeny and its zones, distribution of coal-bearing and oil-bearing formations, mineral waters, gases, seismicity and much more), can be satisfactorily resolved without knowledge of not only the tectonics of the region, but also the basic regional tectonic concepts. After a critical review of all the material accumulated in large quantities over 60 years, and especially over the last 10 years, on the geology of Central Asia, the author arrives at a certain logical sequence of basic conclusions that are relevant to each of his earlier ideas expressed by various persons (see the article).

In the summer of 1932, the Leningrad Mining Museum organized an expedition to collect materials on the mineralogy and petrography of volcanoes located in the region of Petropavlovsk. At the time of departure, it became known that a parasitic crater had formed at the foot of the Klyuchevskoy volcano. Upon arrival in Petropavlovsk, it turned out that a second parasitic crater had formed there, which at that moment was active. The work plan was changed, and the author immediately left for the Klyuchevskoy volcano. New parasitic craters formed in the locality of Kirgurich. From the village of Klyuchi they are located 16 km to the south, and from the summit of the Klyuchevsky volcano 20–25 km to the northeast. In total, two craters appeared. The first was named Kirgurich, after the name of the locality, the second – Tuila. Kirgurich is located near the end of the birch forest zone at an absolute elevation not exceeding 600 m. Tuila arose later than Kirgurich and is located 1300 m to the northeast of it at an absolute elevation of 500–530 m. In terms of absolute elevation, among all the parasitic craters on the eastern and northern slopes of Klyuchevskaya, the new craters are situated the lowest. The new parasitic craters are located on the same line as the Kharchinsky and Zarechny volcanoes, on the one hand, and the old parasitic craters located to the south of the new ones, on the other. On this line, the new craters are closest to the old parasitic craters.

Using the mineralographic method applied to ores from the Nikitinsky mine, a mineral very similar to pyrite was discovered, but some of its features, such as a pinkish tint, prompted us to subject it to special investigation, after which we arrived at the hypothesis that it might be cobaltite (CoAsS). In addition to cobalt, the mineral aggregates contained chalcopyrite, pyrite, pyrrhotite, and a non-metallic mineral. The presence of cobalt is of great importance, since pyrite and pyrrhotite are frequently found in the Turinsk copper deposits and almost always follow the copper ores. While studying collections from the Dashkesan cobalt deposit, molybdenite (MoS₂) was detected in two samples of cobalt ore. In these samples, molybdenite occurs only at the contact between cobaltite and magnetite, locally forming thin veinlets ranging from fractions of a millimeter to 3–4 mm in thickness; occasionally, the molybdenite is disseminated. The discovery of molybdenite in the Dashkesan cobalt deposit necessitates a detailed examination of the collected material to determine the potential for mineralization both within the cobalt deposit and in its vicinity.

In this article, the author attempts to present in general terms his views, on the one hand, on the methodology for studying chrome deposits in the most general sense, and on the other hand, on the geological nature of these deposits. The author himself has extensively studied primarily the platinum-bearing chromite iron ores of the Urals. For purposes of identification, non-platinum-bearing chromites were also studied alongside this work. The latter were studied in more detail in Transcaucasia (in the area of Lake Gokcha), as well as in the Northern Caucasus (in the area of the Bolshaya Laba River). We can outline the following genetic types of chrome-spinel formations: 1) chrome-spinels formed in the earlier magmatic period; 2) accumulations of chrome-spinels formed in the later magmatic period, when the main mass of the host rocks had already been nearly formed; 3) chrome-spinels formed by hydrothermal processes, mainly during the serpentinization of rocks.

The material for the present work consisted of data from 18 exploratory boreholes, drilled by the Geological Exploration Trust of the Central Chernozem Region (CChR) in the southeastern part of the region and along its border with the North Caucasus Krai, which encountered undoubted Carboniferous deposits. The importance of studying the stratigraphy of the Carboniferous within the CChR is determined by the geographical position of the province between the Donetsk and Moscow coal basins. Thus, the northernmost borehole in the scope of our research, in Novy Oskol, is located 240 km from the southernmost outcrops of the Moscow Basin Carboniferous and 200 km from the northernmost outcrops of the Donetsk Basin Carboniferous (see the article). Consequently, the described Carboniferous deposits serve as a connecting link between these basins, which are composed of facies-wise entirely different deposits and, according to the previously prevailing viewpoint, represented the results of fundamentally different geological processes.

The present work by G. Säve-Söderbergh, despite its modest title: "Preliminary Note on Devonian Stegocephalians from East Greenland," presents the content of a very interesting study devoted to the description of the finds of the oldest Tetrapoda known to date. It should be said that the discovery of reliable remains of these in the Devonian had long been eagerly anticipated in the scientific world. The author was a participant in the Danish East Greenland Expedition of 1931, which worked under the leadership of Dr. Lauge Koch and discovered a fauna of coelacanths and other fishes in the Upper Devonian (layers of the Upper Red Sandstone in the Mont Celsius area on Ymer Island at 73°10' N and 23° W). The accuracy of the age determination is confirmed by the work of the renowned Swedish scholar E. Stensiö (see the article).

In connection with the plan and pace of development of the mining and geological exploration industries, mine surveying currently faces a number of important tasks, namely: A. In terms of technical reconstruction and the technical revolution: 1) Elimination of technical backwardness (introduction of a unified coordinate system, safeguards against gross errors, introduction of the "z" coordinate, etc.); 2) Improvement of survey accuracy (accuracy of angle measurements, distances, orientation, etc.); 3) Introduction of new survey methods and techniques (precise tacheometry in mines, photomechanical reproduction of plans and other documents, application of photogrammetry to open-pit surveying, etc.); 4) Adaptation of mine surveying techniques to the new rates of mine development (consoles, suspended theodolites, new orientation methods). B. Adaptation of mine surveying to serve planned construction (see the article). C. In terms of general and organizational questions (see the article)

The general theory of lines of position and gradients provides great clarity and simplicity in matters of graphical adjustment and determination of point position errors. In geodesy, when determining the position of unknown points on a plane, we directly measure horizontal angles and distances, which can be considered as functions of two variables (coordinates). To a given measured value of a function there corresponds a certain geometric locus of points on the plane—a certain line, which we shall call the line of position. Let us turn to the errors of point position. The position of the projection of a point onto the horizontal plane is determined by the intersection of two lines of position of two measured functions. Graphical adjustment using gradients is highly expedient in repeated trigonometric determinations of moving points, for example in landslide areas, in areas subject to displacement due to underground mining, and the like. Once constructed, the error figure with the calculated gradients will serve as a convenient means for further studies of the movement of the point being determined.

The classification of the 32 types (or groups) of crystal symmetry, i.e., their division into systems, or syngonies, can be based on various principles. Among these principles, the following two are the main and most natural ones. It is possible to classify the types (or groups) of symmetry, i.e., specific spatial combinations of symmetry elements as such, in themselves, without relation to the complexes of possible faces and edges of the crystal to which these symmetry types are inherent. Let us call such classifications "purely geometric." It is possible to classify the types of symmetry, taking into account the properties of those complexes of possible faces and edges of the crystal, in other words, those spatial lattices to which these types (groups) of symmetry are inherent. Let us call such classifications "crystallographic." The proposed classification, nomenclature, and symbolism are closely connected by a single principle, based entirely on a genetic feature — on the generating elements of symmetry.

(Report delivered on March 11, 1933, at a meeting of the departments of the petrographic-mineralogical cycle of sciences, dedicated to the 50th anniversary of the death of Karl Marx.) The history of crystallography, its main trends, and recent achievements are presented in a reference and concise form. This basis serves to examine the problems of crystallography, which are largely solved in accordance with the demands of industry. Among the contemporary tasks of crystallography, several groups of problems can be distinguished: a group of physical problems linking the physics of phenomena with their geometry; a group of chemical problems; a group of problems related to physico-chemical phenomena; and crystal X-ray measurement (see the article).

The method of calculating grid densities previously used in crystal-chemical analysis yields results that do not coincide with those for the real structure, because we are dealing not with one but with several parallelepipedal systems of points interleaved within one another. This circumstance was already noted by E. S. Fedorov himself in his article "On the question of determining the density of atomic arrangement in crystal faces." However, the method of calculating grid densities according to Fedorov can be used not only for individual parallelepipedal lattices, but also in the presence of a structure forming lattices similar to the aforementioned "pseudo-octahedral" one, for calculating geometric atomic grid densities.

Study of the pegmatite deposits of tinstone from East Transbaikal yielded a number of results indicating a relationship between the form and genesis of this mineral. A series of cassiterite crystals found in pegmatite veins confirms the association of pyramidal crystals with high-temperature formation conditions. The described crystals of tinstone from the Zavitinskoye deposit, of high-temperature character, were of interest in that they exhibited a prismatic habit, which is characteristic of low-temperature pegmatites. Measurement of a single crystal showed that it is a dipyramid with angles between the normals to the dipyramid faces equal to 58°16'.

This experimental work was undertaken with the aim of determining the main mechanical characteristics of the iron ores and the enclosing quartzites of the Lenin (formerly Kolachevskii) mine in the Krivoy Rog district. The experiments carried out made it possible to establish: 1) The independence of the forms of failure of rock cubes solely from the nature of the packings. 2) The delay of compressive deformation under high loads. 3) An almost complete proportionality between elastic deformation and stress in most samples at unit loads exceeding 50–150 kg/cm², and some deviation from this strict proportionality at lower loads, which in general agrees with the aforementioned conclusions of E. E. Woo. 4) The constancy of Poisson's ratio with increasing load, and its determination for iron ore and quartzite by means of a special modification of the Martens mirror apparatus. 5) The excess of residual transverse deformations over elastic ones, and the excess of elastic deformations over residual ones in the direction of compression.

This article is the first attempt to develop a theory for calculating the electromagnetic systems of magnetic separators. At the beginning of the article, the general principle of the theory based on the experimental study of the magnetic field is described, and the general information necessary for constructing this theory is provided. The following presents the results of the study of the magnetic field of the M.B.N.6 separator (with ring magnets) and the formula for determining the magnitude of the magnetic force at various points in the field. Using the law of mechanical similarity, the obtained formula becomes general for all cases of any separator of the type under study (with ring magnets). This generalization makes it possible to specify the conditions for determining the optimal values of the parameters that define the magnetic field of a separator of this type, as well as the number of ampere-turns in the separator coil.

The use of a motor-generator set with a flywheel (Ward-Leonard-Ilgner) as the main drive of a synchronous motor is dictated by the presence of a hydraulic coupling connecting the shaft of the main motor to the shaft on which the alternating voltage is located. The dynamo and the flywheel are mounted on the latter. This coupling replaces the automatic slip regulator of the flywheel, which operates at a constant speed of the synchronous main motor. This article describes the installation of the hydraulic coupling and the concept of its use in the Ward-Leonard-Ilgner system with a synchronous main motor.

In this work, the method of direct measurement of the transition resistance, as well as the thickness of the gas film that gives rise to it, was employed using alternating current superimposed on the polarizing direct current. This work allows the following conclusions to be drawn: 1) the existence of transition resistance at a mercury cathode is beyond doubt; however, transition resistance is not the sole cause of hydrogen overvoltage; 2) the formation of a hydrogen film that gives rise to transition resistance begins at very low cathodic polarization; 3) the maximum resistance of the film corresponds to the beginning of the increase in current on the current density-potential curve; 4) with an increase in direct current density, the magnitude of the transition resistance decreases.

The purpose of this note is to simplify the method proposed by Academician N. M. Krylov for expanding a given function in a series in Jacobi polynomials. By constructing a priori an expansion with uniform and absolute convergence, we show, without relying on the Riesz-Fischer theorem, that it can be identified with expansions in Jacobi polynomials.

In his profound studies devoted to functions of several variables, Kronecker showed that the problem of determining the number of roots of a system of algebraic equations (see the article) satisfying a certain condition is related to the evaluation of an integral. The criteria for the multiplicity of solutions of a system of equations provided by algebra are complex. It is natural to seek simpler methods. Our investigation shows that this can hardly be achieved by applying the Kronecker integral without profoundly modifying its structure.

This work refers to the consideration of the case of a limit theorem with respect to independent variables—a case that was developed by Academicians Markov and Lyapunov, resulting in the conditions known in science as Lyapunov's conditions. Further work on the issue under consideration was mainly reduced to developing new methods of proving the limit probability theorem and did not yield a significant extension of Lyapunov's conditions. It is therefore natural to pose and attempt to solve the problem of extending Lyapunov's conditions, to which this work is devoted.

We consider a perfectly elastic sphere, the material of which is subject only to the gravitational attraction of its own mass. It is then assumed that the sphere contains an incompressible core. Assuming that the thickness of the shell is small relative to the radius of the core, we obtain a formula for the stresses in meridional sections, which was previously derived by various authors (including Academician Bynnik) under entirely different assumptions.

We shall confine ourselves to considering a ball mill consisting of a cylindrical drum with a horizontal axis of rotation and loaded with a mixture of balls and ore. The motion of a ball in a ball mill can be divided into three periods. During the first period, the ball has no relative motion with respect to the rotating drum and moves as if rigidly connected to the latter. In the second period, the ball separates from the drum wall but still rests on the ball below it, moving along the latter. Finally, the third period begins at the moment when the moving ball leaves the lower ball. Studying the motion of the ball during the first and third periods presents no difficulties. Therefore, the subject of further investigation is only the second period. The motion of the ball under consideration takes place in a vertical plane perpendicular to the axis of rotation of the drum.

Previously, I considered a problem related to the shape of airplane wings, concerning the motion of an ideal incompressible fluid in the presence of a stationary cylindrical solid body. In that case, the contour being flowed around is assumed to be algebraic, and the fluid velocity at an infinitely large distance from the solid body is constant in magnitude and direction. At infinity, the velocity of the ideal incompressible fluid is constant in magnitude and direction. In this article, we show that the application of the aforementioned conformal transformation leads to a contour of the obstacle representing an algebraic curve of order 2m (see the article).