Book reviews TV. YOURGRAU and S. MANDELSTAM: (Second Edition). Pitman, London,
Variational Principles in Dynamics and Quantum Theory 1960.
xi + 180 pp., 32s.6d.
THE FIRYT EDITION of this stimulating book was reviewed in this journal by L. ROSENFELD in 1955 (J. At?no+. Terr. F&s. 7, 110). The new edition differs from the earlier one by the inclusion of some significant new material: two chapters, which deal with the formulations of qllantum theory associated mainly with the names of BOHR and SOMMERFELD and of SCHR& DINCER respectively, now have postscripts suggested by remarks addressed to the authors by Professor SCHR~~DINGER after the publication of the previous edition; there is a new fifteen-page chapt.er on “The principles of FEYNMAN and SCHWINGER in quantum mechanics”; and a paper by YOURGRAU and RAW on “Variational principles and chemical reactions”, fist printed in S~covo Cimento in 1957, appears as an appendix. Although the laws of classical mechanics and electromagnetism can be expressed through variat,ional principles, and although the Hamiltonian formulation of these laws is the basis of the nsual approach to the more general laws of quantum mechanics, variational principles do not have the prominent place in quantum theory that they occupy in much of classical physics. Within the past 12 years, however, FEYNMAN and SCHWINGER have shown, by methods which are superficially very different but, are in fact equivalent, that the laws of quantum mechanics can he formulated with a new succinctness in terms of an action principle which reduces, in the classical limit, to the variational principle of least action. The authors describe and discuss this important development in quantum theory, in the general setting of their concise review of the place and history of variational principles in physics. This is a vahlable addition to a book which has already been welcomed for the cold clear light which it shines on topics which have too often in the past been viewed through a haze of mysticism. R. M. SILLITTO
C. H. 13. PRIESTLEY: Turbulent Transfer in the Lower Atmosphere. Press and Cambridge University Press, 1959. vii -t 130 pp., 28s.
The University
of Chicclgo
THE STUDY of atmospheric turbulence is among the most highly specialized and, by repute, among the most “difficult” branches of meteorology. Such study tends at present to be restricted to small-scale phenomena: apart from the intrinsic importance and direct applications of results obtained at this scale, however, there is general agreement that such studies may bear fruit in the solution of problems relating to much larger-scale phenomena, since the transfer of atmospheric properties implicit in the “general circulation” of the atmosphere is mainly effected by the large-scale eddies known as depressions and anticyclones. The book under review is concerned with an explanation of the detailed mechanism of the vertical transfer of momentum, heat and matter which is effected in fine-scale atmospheric turbulence. It naturally leans heavily on the measurement techniques and results obtained by the team of Australian workers which the author heads, but is by no means neglectful of the experimental and theoretical work which has been done elsewhere. The scope of the book is best illust,rated by the chapter titles which, following a brief introduction, are: “The Eddy Flrlx and its Measurement”; “The Shearing Stress and the Wind Profile”; “Heat Convection and the Temperature Profile”; “The Spectrum of Turbulence and the Structure of Free Convect ion” : “Theories of Buoyant Motion”; “Evaporation”; and “Evolutionary Aspects of Energy Transfer”. The book was written, not as a text-book, but as an extension of a series of lectures delivered by the author on a visit to Chicago. It is an obvious “must” for workers in the specialized fields indicated in the chapter titles. It represents, however, a piece of work so remarkable in its conciseness of writing and in its treatment of the various topics as to be unsuitable for any non-specialist who does not f&t make himself familiar with the contents of 0. G. SUTTON'S Micrometeorolog~y which is one of the few textbooks in any language in this field of investigation. D. H. MCINTOSH
221