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lence”, too, would then be generally explained as a crumpling of the streamlined isobars, and the disturbance of the flame front in wide tubes, to which a great deal of attent.ion is given, would follow as one of many corollaries. OLIVERC. DE C. ELLIS.
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Technische Adsorptionstoffe i n der Kontaktkatalyse. By FRANE KRCZIL. xxxi 726 pp. Leipzig: Akademische Verlagsgesellschaft, 1938. Price: 40 RM. This volume is a storehouse of information concerning a large number of catalysts of the more porous type used in a great variety of heterogeneous reactions. After a brief introductory chapter the book is divided into three parts. Part I discusses the many types of surface-active catalysts which have been and are being used in chemical processes. Single contact agents, mixed agents containing two substances, and mixed agents containing more than two substances are considered in that order. All types of active carbon, silicious materials, silica gels, alumina, and hydrated aluminum oxides of various kinds are among the single surface-active substances considered. Mixtures of these together with metals, metallic oxides, as well as non-metallic oxides are discussed as mixed contact agents. Methods of preparation of the catalyst are often briefly given. Part I1 concerns the use of these adsorption types of catalysts in a number of inorganic reactions such as oxidations, reductions, decompositions, and a variety of syntheses. The third section, and this occupies roughly two-thirds of the book, treats of the many uses of these adsorption catalysts in the wide range of catalytic reactions covered by the field of organic chemistry. The factual material covered by this book is remarkably complete. The author makes no attempt to consider theories of contact catalysis, since he is interested in presenting as fully as possible all of the experimental results as well as the industrial procedures in this field. References are made t o patent literature as well as to the usual journal sources. A separate section of the index is devoted to listing the patents on the subject from all countries. All chemists interested in contact catalysis will find Dr. Krczil’s book an important reference work in the field. The completeness of the index makes the work particularly valuable to industrial laboratories. L. H. REYERSON. Applied Mathematics i n Chemical Engineering. By T. K. SHERWOOD AND C. F. REED. New York: McGraw-Hill Book Company, Inc., 1939. Price: $4.00. This is the book that many people have been waiting a long time to see. I t represents the ideal combination of the talents of a mathematician and an engineer to make mathematics a really useful tool rather than an abstract mental exercise. Although its title might imply that its usefulness is limited to chemical engineering, such is not the case. Anyone engaged in constructive scientific or technical work will find a great deal of valuable material here, even though the bulk of the examples are taken from the field of chemical engineering. Even those who have spent years in adapting the instruments of mathematics to their particular needs will find many useful suggestions here for solutions and approximation. Many teachers of graduate students will find i t ideal as a supplementary text in courses which include the use of mathematical treatments. As a matter ofPact, a graduate course based largely on this book would be very valuable for chemists, physicists, and engineers. The scope of the work can best be indicated by citing the chapter headings, which are as follows: (1) Integration and Differentiation; (2) The Use of Differential Equations; (3) Solution of Ordinary Differential Equations; (4) Applications of
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Partial Differential; (5) Infinite Series; (6) Partial Differential Equations; (7) Numerical Analysis; (8) Graphical Treatment of Chemical Engineering Processes; (9) Theory of Errors and Precision of Measurements. C. C. FURNAS.
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Ferrorcagnetismus. By R. BECKERA N D W. DORING. 25 x 17 cm.; viii 440 pp. Berlin: J. Springer, 1939. Price: unbound, 39 RM.; bound, 42.60 RM. In the investigation of ferromagnetism there are two groups of questions to be considered: the first is concerned, broadly speaking, with the occurrence of intrinsic spontaneous magnetization, and its magnitude and temperature variation, and the second with the details of the variation with field of the bulk magnetization and with various secondary effects. This book deals mainly with the second group. There are six sections. The first two deal briefly but illuminatingly with fundamental principles and with the general theory of ferromagnetism. The third section, more than a third of the whole book, deals with magnetization processes in ferromagnetics and the factors controlling them. An excellent opening chapter introduces questions connected with crystal, strain, and field energy, describes boundary movement and gradual change of direction of magnetization in spontaneously magnetized regions, and indicates the part they play in the course of magnetization. These topics are discussed in detail in subsequent chapters with reference to initial permeability, coercivity, high frequency permeability, and magnetic after effects. The thermal, electrical, and strain effects accompanying magnetization are then considered, and also the peculiar effects of a magnetic field on elastic properties and on the damping of mechanical oscillations. The final section, which deals with magnetic materials in relation to technological applications, opens with an account of precipitation processes in alloys and their effect on magnetic properties. Technological requirements for different purposes are clearly set forth, and the properties of a large number of both commercial and laboratory alloys are discussed in the light of the general theoretical outlook. From the point of view of a specialist the book is particularly useful for the remarkably comprehensive theoretical treatment, much of which is here published for the first time, of the interrelations between magnetization and strain, both applied and internal. The formal completeness in this one direction does, however, to some extent distort the impression given of ferromagnetism as a whole. None the less, the general parts of the book give good surveys of the present position, and show a wide appreciative knowledge of relevant work, though the selection of references to the literature sometimes seems rather arbitrary. The three hundred and nineteen diagrams, with explanatory captions, are an admirable feature. The table of contents makes the general plan clear, but the index is very inadequate. The book a t once takes its place as a valuable contribution to the literature of magnetism. It will be of great interest, however, not only to magneticians, but also to all those concerned with the properties of metals and alleys. EDMUND C. STONER.
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Reine Metalle. Edited by A. E. VAN ARKEL. 24 x 16 cm.; vii 574 pp. Berlin: Julius Springer, 1939. Price: unbound, 48 RM.; bound, 49.80 RM. The increased interest in the metallic state which has been so conspicuous in recent years has called for a more complete knowledge of the properties of pure metals. Absolute purity being unattainable, and the removal of traces of foreign elements from several of the metals being very difficult, it is important to know what degree of purification has been reached in esch instance, and how products of high
