BIBLIOGRAPHY

R. SEELEGER, Einführung in die Physik der Gasentladungen, 2nd rev. and enlarged ed., 1934, Lpz., Barth, 1934, XI, 563, p. 243, figs. Mk. 48.

R. SEELEGER, Introduction to the Physics of Gas Discharge.

One opens Prof. Seeliger’s voluminous work on the physics of electrical phenomena in gases, modestly entitled by him an “Introduction” to this field, with great interest. In recent times several monographs devoted to the same subject have appeared in English, German, and French. Nevertheless, Seeliger’s book is of great interest to the specialist, since it contains a valuable and new presentation of the entire field of gas discharge.

The book is distinguished by the great freshness of the material presented: the literature on the physics of gas discharge has been taken into account almost in its entirety, including 1933. Moreover, the author himself is one of the leading workers in discharge physics, which undoubtedly gives the whole monograph a very lively character. Naturally, the chapters in which Prof. Seeliger himself is working very actively—glow and arc discharge—are the most successful. For this reason, in many places the book does not have the character of a dry list, or a mere description of material. Every fundamentally important fact has been critically reworked; ambiguities and shortcomings of one or another scientific work are indicated, and the author’s opinion on all disputed questions is clearly brought out. An important feature is also the frequent indication of still unresolved problems, which should give the reader an impetus for further work. It should also be noted that the author broadly illuminates a number of questions that are now current, such as, for example, processes in controlled gas discharges, the emission of light by gas discharges, and others.

While giving the prepared reader abundant material, the book nevertheless also has substantial shortcomings. It repeats the same deficiencies that were present in the first edition of Seeliger’s monograph, published in 1927. Reading the book is made considerably more difficult by the treatment of the same questions in different sections of the book. Thus, for example, the same phenomena are first discussed in the introduction, then in the section on elementary processes, in the descriptive part of one or another type of discharge, and finally in the theoretical part; moreover, such fragmentation of the material is not accidental but represents the author’s basic line. Undoubtedly, it would have been more expedient to concentrate the description and theoretical explanation in one place. Endless references to other sections of the course greatly tire the reader, who in no way can obtain an integral picture.

It should also be noted that the book’s center of gravity is a survey of experimental material. Not too much attention is devoted to the theoretical interpretation of the observed phenomena. Often the theory is given only qualitatively. Undoubtedly, it would be desirable to have a more detailed and thorough discussion of the theory of gas discharge.

It is known that recently, in theoretical physics, the methods of the new wave mechanics have been developing very successfully in applications to processes

between elementary particles. Unfortunately, this new area, in which serious successes have been achieved in questions of gas-discharge physics (for example, recombination between particles), has found no reflection in the book.

The book is divided into 8 large chapters.

The first chapter considers questions of the conductivity of a gas gap, the conductivity of flames, sparks, artificial and natural conductivity, and protection against stray currents.

The second chapter treats data relating to the mobility of ions, their recombination, and diffusion. Here the physical nature of various ions, the effect of force fields on the motion of ions, and the very important questions for gas discharge of volume space charges are also explained.

Material on elementary processes in a gas discharge is collected in the third chapter of the book. Here one finds the motion of electrodes in a gas, elastic and inelastic collisions of electrons with atoms and molecules, excitation and ionization of a gas filling a discharge tube, total effective cross sections, attachment of electrons, and other phenomena. In this large chapter special sections are devoted to questions of the interaction between radiation and atoms, absorption of radiation, collisions of the second kind, photon kinetics (light quanta). The kinetics of positive ions, the processes of ion recombination, the excitation of light in collisions, etc., are also reflected.

In this chapter a separate paragraph is devoted to effects at the walls of vessels in which the discharge occurs. Such effects include the emission of electrons upon ion impact, recombination processes, collisions of the second kind, and thermal and mechanical processes. Here, too, material is presented on probes, which are one of the most widespread methods for studying processes in a gas discharge.

The fourth and fifth chapters deal with the general properties of the discharge and the Townsend discharge, ignition and development of the discharge, intermittent discharges, transitions from one form of discharge to another, and processes in controlled discharges.

The sixth chapter is devoted to the glow discharge. Much attention is paid to the principal parts of the glow discharge: the cathode parts, the positive column, and the anode parts. Here questions essential for introduction into lighting technology—the energy balance in the positive column of the discharge—are also discussed in a lively manner. A relatively small place in this chapter is occupied by the section on electrodeless discharge. Several pages are also devoted to chemical processes in the discharge.

The arc discharge is characterized in the seventh chapter: radiation, processes in the cathode spot, types of arc discharge, ignition, mechanical effects, distribution of potential, etc.

Special attention is given to theoretical questions in the eighth chapter. The results of mathematical theories for the glow and arc discharges are presented rather briefly. The high-frequency and electrodeless discharge are covered too little. In this last chapter not only the mathematical theory is given, but often also a qualitative explanation of phenomena described in the sixth and seventh chapters; such an explanation is given only here. This last chapter is, as we have already indicated, less successful in comparison with the chapters devoted to experiment. Interest in it is aroused by the explanation of theories of the thermal arc and of theories explaining the arc by the extraction of electrons from the cathode by a strong field.

The book is not intended for the unprepared reader, but for a prepared reader the abundance of fresh and critically presented material is very substantial.

A translation of the book into Russian without a substantial reworking of the book, without strengthening the theoretical part, would hardly be expedient.

For a physicist specializing in gas discharge, the book will provide much that is interesting and will reveal the author’s original point of view on many controversial questions, giving the reader the material necessary for further work.

G. V. Spivak