Reviews of Books The Thermodynamics of Soil Solutions. By G. SPOSITO (Clarendon Press : Oxford University As the title implies, this book is directed primarily towards the application of thermodynamics to the highly complicated aqueous solutions which are in equilibrium with various types of soil. However, unlike some other books on specialised applications of thermodynamics, there is much in this volume which will be of interest and value to physical chemists interested in similar, but less complicated, systems and solutions. Throughout the book the author not only stresses the applications of thermodynamics to real systems, but also emphasises the many limitations to its use. The first two chapters review some fundamental concepts of chemical thermodynamics and care has been taken to explain these and their consequences in greater detail than is common in many textbooks of physical chemistry.These chapters would be useful reading for anyone wanting to refresh his or her ideas about the nature of some basic thermodynamic assumptions and definitions, such as the nature of the standard state. However, the author has adopted the unusual approach of defining activities in such a way as to make them dimensionless, with the unfortunate consequence that the usually dimensionless activity coefficients must be assigned the dimension [concentration]-l or [molalityl-l. One error in this section (p. 25): the implication that the conditions for equilibrium when temperature and pressure are held constant is dU = 0 arises from a slightly lax definition of chemical potential a few pages earlier.The remainder of the book deals with detailed applications, chap. 3, 4 and 5 being devoted to solubility equilibria, electrochemical equilibria and ion exchange, respectively. In each case the author shows how the many complex interactions in soil-solution systems can be broken down into the contributing parts. Both soil chemists and classical thermodynamicists should find these sections of considerable interest. Most of the final third of the book is devoted to a consideration of ion exchange, one chapter being devoted to the thermodynamic background and a second to molecular considerations. The final chapter considers the problem from a soil physicist’s point of view and discusses the properties of the water rather than of the solutes and solid phases present.At no stage does the author shirk from presenting his work in a properly quantitative way and these last chapters particularly are mathematically demanding. Certainly they are such as to be useful to only the most dedicated undergraduate and much of the book is really directed towards postgraduate students and research workers. However, one excellent feature of the book will make some of it useful reading for undergraduates. At the end of each chapter the author includes both detailed notes and references to specific points raised in the main text and also a comprehensive, annotated further-reading list for more general points. Many references are given to recent work and the whole presentation seems to be free of typographic errors. The book concludes with three indexes including a comprehensive one on the symbols used throughout the text .This book should certainly be purchased for the library of any institution or individual interested in the physical chemistry of soils. Its price and relatively narrow area of specialization mean that it is unlikely to be widely purchased by undergraduates, but could be useful in showing how many concepts from classical thermodynamics and electrochemistry can be extended to apply to the highly complex interactions encountered in soil-water systems. A. D. PETHYBRIDGE Press, Oxford, 1981). Pp. xii + 223. Price E24. Received 1st April, 1982 343 13432 REVIEWS OF BOOKS Mass Spectrometry. Principles and Applications. By I. HOWE, D.E. WILLIAMS and R. D. BOWEN (McGraw-Hill, New York, 2nd edn, 1981). Pp. xii+276. Price E24.95. This is a revised version of the book written by Drs Howe and Williams in 1972 which was a first-class introduction to mass spectrometry. Such has been the development of the subject over the last ten years that it was now out-of-date in some respects. This revised edition remedies this and although the authors state that the book is not intended for experts, I am sure that many practising mass spectroscopists as well as newcomers to the field will find much to interest them. After a short opening chapter on instrumentation, there follow four chapters on the underlying principles of ionisation processes and the kinetics and energetics of unimolecular and bimolecular reactions of ions.The reader is given a good qualitative description of the role played by kinetics in determining the observed mass spectrum and the chapter on energetics of unimolecular reactions gives a concise account of the present position in a branch of the subject in which the authors have made a number of important contributions. Personally, I should have liked to have seen a slightly more extended account of bimolecular reactions but there is sufficient here to give the reader an indication of what may be found in the literature. The remainder of the book is devoted to applications, major chapters being devoted to the interpretation of electron impact spectra and the analysis of mixtures. In the last decade, on-line data systems have become increasingly available and a short chapter on computer techniques provides a useful introduction to what is now possible with such a system. A selection of analytical applications and a brief description of isotopic labelling methods lead to an unusual final chapter in which the questions to be considered in choosing a mass spectrometer system are discussed. Overall, this book can be recommended as a readable and well-balanced introduction to the subject. K. R. JENNINGS Received 22nd March, 1982