of the former and has been completely rewritten. The character of the work is already known to many, but it may be mentioned for the benefit of readers who may be seeking only a general descriptive text, that the work is an analytical and critical account of some of the most erudite contributions to physical science of the day, and premises on the part of the reader a familiarity with those phenomena of atomic physics which are correlated to the development of the theory of atomic structure.
The work is in two general divisions, Part I, The Nucleus, Part II, The Extranuclear Structure. The additions in the present edition occur mainly in Part II, only relatively small changes having been made in Part I. The chapter headings are: under Part I, I Historical and general, lI The passage of swift corpuscles through atoms, III Radioactive considerations, IV The disruption of the nucleus by alpha-particles, V Positive Rays, VI Classical X-ray considerations, VII The structure of the nucleus, VIII A digression on optical spectra.
Under Part II, IX The dynamic model of an atom with one electron, X General principles for systems not simply periodic. Hydrogen-like atoms with two quantum numbers, XI The optical spectra of the general atom, XII Excitation potentials and absorption, XIII X-ray spectra and the inner electron groups, XIV The periodic system and the theory of quantum orbits, XV Multiplet structure and anomalous Zeeman effect. XVI Magnetic properties and atomic structure, XVII Static atom models, XVIII Wave theory and quantum theory, XIX Concluding remarks. Numerous bibliographical references relating to the topic discussed are given at the end of each chapter.
The value of a book which has passed through three editions in four years is established. The intrinsic scientific value, the thoroughness of presentation and the straight-forward method employed of indicating inadequacies as well as merits of prevailing theories, contribute to place the work on a high plane among the physicist's sources of information on the most fundamental problem of physics.
L. E. P.