Bibliography

ABRAHAM-BECKER. Theory of Electricity. Translated from the German by V. A. Fokina under the editorship of T. P. Kravets. Pp. 281. ONTI. Main Editorial Office of General Technical Literature. L.—M., 1936. Price in binding: 5 rubles 25 kopecks.

The book under review is a revision of the first volume of M. Abraham’s well-known handbook; the second volume, rewritten by R. Becker, appeared in Russian translation somewhat earlier under the title R. Becker, Electron Theory. Every physicist knows “Abraham” well. At least three generations throughout the world studied the theory of electricity from this book. This book has its own history. Its basis was the Introduction to Maxwell’s Theory, written by Föppl and published in 1894. In 1904 this Introduction was reworked anew by M. Abraham and issued as the first volume of The Theory of Electricity; the second volume, devoted to electron theory, was compiled by Abraham himself. Thereafter, during the author’s lifetime, the book went through seven more editions and became an indispensable aid for the serious study of the theory of electricity. Naturally, it exerted a decisive influence also on the teaching of the theory of the electromagnetic field. The elegant vector form of exposition adopted in it, the system of notation, and so on—all this entered the everyday usage of the higher school wherever the teaching of theoretical physics stood at a modern level. After the author’s death, for a fairly considerable number of years the book was not reissued, and only in 1931 did the eighth edition appear (and the following year—the ninth) in a new revision by R. Becker.

Anyone who knows the old “Abraham” will immediately notice the special features of the new revision. The most essential of these is the far greater concreteness of the exposition. Remaining at the same high theoretical level, the book has come to satisfy to a considerably greater degree the needs of the experimental physicist and even of the electrical engineer. This was expressed both in an especially detailed clarification of the physical content of the theory and in the very external form of presentation. The number of figures has been considerably increased; in the theory of alternating currents, vector diagrams accepted in engineering are widely used; problems have been added according to the level of difficulty accessible to students, and their solutions are given, etc.

As regards content, the first volume covers the phenomenological part of the theory of the electromagnetic field; the microscopic theory, as stated above, is assigned to the second volume. There is no need to dwell in greater detail on the contents of the first volume; we shall confine ourselves to a brief list of the sections: A. Vectors and vector fields; B. The electrostatic field; C. The electromagnetic field (magnetic vectors, electrodynamics of media at rest, electrodynamics of quasi-stationary currents, electromagnetic waves); D. On energy and force in Maxwell’s theory. E. Problems with solutions. F. Summary of formulas and notation.

One may debate the placing at the forefront, in a modern exposition, of an exclusively phenomenological, macroscopic theory. It seems to the reviewer, however, that such an arrangement of the course has so far been dictated not only by a sense of respect for the original construction of the book by its author, but also by reasonable didactic considerations. However tempting it may seem to take the microscopic picture as the basis and from it arrive at the laws in macroscopic systems, such a construction would inevitably prove very complicated. We see no harm in the fact that the exposition in the new “Abraham” begins with the phenomenological ...

theories and ends with the electron theory, and not the other way around. Ultimately, every experimental physicist (let alone every electrical engineer) mostly has to deal with macroscopic capacitors, transformers, etc.; and he must above all know firmly the laws of phenomena in these macroscopic systems.

Throughout the book the absolute Gaussian system of units is adopted. Since the question of the system of units has recently been the subject of discussion (see, for example, A. Sommerfeld’s article, Physikalische Zeitschrift, 1935, No. 23/24), we shall cite R. Becker’s arguments in favor of retaining the absolute system of units in the presentation:

“In the choice of units of measurement I have everywhere adhered to the latest edition of Abraham. Everywhere the Gaussian system of measures is used, in which the energy density in vacuum is equal to

$$ > \frac{1}{8\pi}\left(E^2+H^2\right)\frac{\text{erg}}{\text{cm}^3} > $$

and which assigns the same unit to the dielectric constant and the magnetic permeability of vacuum. At present it is impossible to satisfy simultaneously, in the choice of a system of measures, the requirements of electrical engineering and of physics, because the ‘electrotechnical’ and the ‘physical’ understanding of Maxwell’s theory differ not only in notation, but also in substance. At the same time, the technical understanding is much more closely linked to the original form of Maxwell–Faraday’s theory than to modern physics.

The electrical engineer regards (even in vacuum) the vectors \(E\) and \(D\) as quantities essentially distinct and standing in the same relation as tensile stress and strain in the theory of elasticity. From this point of view it is, of course, questionable when, in the exposition of the basic propositions, the proportionality \(D=\varepsilon E\) is multiplied by the dielectric constant, which for airless space is taken equal to unity, and when, thanks to this, the equality in dimension of the quantities \(D\) and \(E\) is artificially achieved. Modern physics, on the contrary, has completely abandoned that fundamental distinction between \(D\) and \(E\), which was closely connected with the mechanical theory of the ether. It regards the electromagnetic state in any, even airless, space as fully described by the assignment of one electric vector \(E\) and one magnetic vector \(B\) (or \(H\)). The numerical coincidence in the Gaussian system of measures of \(E\) and \(D\) (in vacuum) is for the physicist not the result of an arbitrary definition, but the expression of the actual identity of both quantities. On the contrary, the introduction of special units for the dielectric constant and magnetic permeability in vacuum seems to him an artificial computational device of the electrical engineer, by means of which the latter brings formulas into a form convenient for his practical purposes.”

The Russian translation has been carried out satisfactorily; however, it contains terminological peculiarities that do not seem to us to have any merit. The term “divergence” is rendered by the rather unsuccessful Russian term “discrepancy”; the translation of the German term Feldstärke by the Russian term “force of the field” instead of the established term “field strength” is quite inadmissible; partielle Differentialgleichungen are for some reason called by the translator “partial (!) differential equations.” In addition to “noted” misprints, we also found a number of “unnoted” ones (for example, on p. 25 \(v''_x+v'_x\) instead of \(v''_x-v'_x\); there also \(v_1\) instead of \(v_n\); the dimension of specific resistance is given as ohm/cm instead of ohm·cm). In addition, the reviewer’s copy is, strictly speaking, a manufacturing defect, since pp. 70, 71, 74, 75, 78, and 79 are absolutely unreadable.

In conclusion, we can only warmly welcome the appearance of the Russian translation of Abraham–Becker’s book and wish that its next edition be executed more carefully.

E. Shpolsky, Moscow