The statistics of numbers and statistical physics both have been extensively investit~ated and reported on in recent years. The statistics of particles in the range of several centimeters to approximately 10 -~ centimeters, on the other hand, has been relatively neglected. It is the author's purpose to establish the theory and practice of small particle statistics with its special problems and application as a branch of statistics in its own right.
The book assumes no intimate knowledge of statistics and all concepts are developed as they are needed. Of especial interest and value is the table of symbols with their meanings that are used in the book.
The first part of this book is concerned with the building up of the statistical tools necessary for small particle size analysis and the representation of their sizes and distribution. Of especial value is one chapter dealing with the differences in determination results. These differences may arise from different methods of determination, different workers doing the determination, differences in sampling technique, etc. The author shows how these differences may be correlated, tested and combined.
Part II deals with the relation of the particle diameter to its other physical characteristics, such as surface area, shape, porosity, etc. In many technological applications it is one of the above, and not the size alone, that determines the physical and chemical characteristics of the particle. For example, the surface area of a catalyst is one of the determining factors in its action. Thus in Part II the statistics for the dependence of these factors on each other are developed. In later chapters specific examples are shown.
In Part III the author discusses how particle size distribution may be decreased by grinding and crushing or increased by flocculation or demulsification. The changes in distribution that occur in these processes are investigated. A chapter on the inhomogeneity of polymers of high molecular weight is included.
Part IV of this book shows the relationship of small particle statistics to the number of statistics on the higher side and to the statistical physics on the lower side. Both the theoretical and experimental aspects of this problem are discussed.
The last section of the book, written by Dr. M. L. Smith, is concerned with the experimental methods for measuring particle size, shape, surface area, etc. Among the methods described in more detail are microscopic determination, various sedimentation methods, the air permeability method and the adsorption of gases at low temperatures. Limitations and advantages of these various methods are discussed in detail.
This book fulfills the need of workers in the industries and laboratories in which the particle size of materials is an important factor. It is at the same time a handbook and text book. Its systematic arrangement provides easily accessible information, while for the novice in small particle work thorough study would be of benefit. Throughout the book many numerical examples are given which aid greatly in the understanding of the material. There are numerous up-to-date references at the end of each chapter. These references together with the detail in the chapter itself form a very complete study of the statistics of small particles.
ROBERT B. CAMPBELL VACUUM TUBE OSCILLATORS, by William A. Edson. 476 pages, diagrams, 16>(24 cm. New York, John Wiley & Sons, Inc., 1953. Price, $7.50.
Although vacuum tube oscillators have been the subject of continuous research and development, reported in many technical papers, there have been few general books on the subject in recent years. Professor Edson has undertaken to bring together in a coherent presentation the large amount of material hitherto available only in scattered journals.
The book has been planned as a classroom text for senior or graduate electrical engineering students, and the material has been so used by Professor Edson at Georgia Institute of Technology. However, this reviewer feels that the book will find wider use as a reference for practicing electronic engineers, or for students in less specialized courses in vacuum tube circuits.