PH. MORSE. Vibration and Sound. McGraw Hill International Series in Physics, New York and London, 1936, p. 351.

F. Morse, Vibrations and Sound.

The literature on acoustics has been enriched by an exceptionally valuable book. Morse’s book is conceived as a systematic textbook setting forth the fundamental theoretical questions of the study of vibrations and sound. However, the book is not an encyclopedia of the enormous body of material in theoretical acoustics. The presentation is conducted in such a way that only the most important fundamental questions are treated exhaustively.

The degree of importance was determined by the author either by the general significance of the theoretical method employed, or by the timeliness of the question in contemporary acoustics. A profound understanding of the development of modern acoustics, combined with a knowledge of theoretical physics, enabled Morse to create an exceptionally valuable manual.

The book is divided into 8 chapters.

Chapter I gives introductory information on mathematics.

Chapter II deals with the simple oscillator. It is valuable that here due attention is paid to energy relations in oscillatory systems. The principal concepts in modern acoustics are developed using the important example of the moving system of a loudspeaker. Coupled oscillations are well analyzed.

Chapter III, dealing with the string, is fairly extensive. The author uses this section to present the basic methods of theoretical physics for wave processes. The fundamental questions of wave propagation, natural and forced oscillations, the establishment of boundary conditions, and strings with inhomogeneous structure are analyzed exhaustively. The theory of the string galvanometer is discussed. The exposition gains greatly from the large number of excellently executed original drawings.

In Chapter IV the oscillations of rods and rigid strings are analyzed.

Chapter V deals with the oscillations of membranes and plates. The mathematical treatment of the question is given on a principled level, without pursuing details. It is extremely important that not only the natural oscillations of membranes and plates are analyzed, as is done in most textbooks, but also the propagation of waves and forced oscillations. This chapter is supplied with excellent perspective drawings of vibrating membranes and plates, which greatly facilitate understanding of the subject. At the end of the chapter questions of membrane oscillations connected with the air cavity are analyzed, which are very important for practice.

Chapter VI analyzes plane waves in tubes and horns. Questions of filters are also considered. The material of this chapter is less interesting and, to a considerable degree, repeats the corresponding chapters from the books of Crandall, as well as Stewart and Lindsay.

Chapter VII, on the radiation and scattering of sound, contains extremely valuable material. The theory of acoustic radiators, the foundations of which are given concisely by Rayleigh, is presented systematically and, moreover, is developed by the author in a number of important cases (for example, the radiation of a piston on the surface of a sphere). The theoretical conclusions are analyzed with topical examples of loudspeakers and microphones.

Chapter VIII, entitled “Standing Sound Waves,” treats the basic questions of room acoustics. A rigorous and systematic exposition of these difficult questions is, to a great extent, timely, since the rigorous theory of reverberation, developed by Strutt, is still very little known and requires popularization and further development.

Interesting, well-chosen problems are provided for all chapters. No substantial defects could be found in the book. The small introductory Chapter I, containing elementary information from mathematics, looks somewhat curious. For such a serious book, a chapter of this kind is simply superfluous. The book has been published impeccably.

S. N. Rzhevkin, Moscow