Bibliography

W. HUME-ROTHERY. The metallic state. Electrical properties and theories. Oxford. 1931.

HUME-ROTHERY. The Metallic State. Electrical Properties and Theories.

In writing his book, Hume-Rothery was guided by the extremely sound idea of the urgent necessity for closer cooperation among physicists, chemists, and metallurgical engineers; moreover, he uses Rosenhain’s proposed term “physical metallurgy” in order to distinguish that branch of metallurgy which studies the structure and physical properties of metals from the study of the extraction of metals from ores. Practical metallurgy has accumulated a large quantity of valuable data, but has advanced comparatively little toward their systematization and toward the discovery of general laws, and has even kept aloof from theory. On the other hand, physicists have for the most part worked without any connection with the problems and development of technology, which, among other things, has had a very negative effect even on the purely scientific value of the results they obtained. The separation from metallurgy has led to the fact that most physical investigations are still carried out on specimens of metals whose properties and characteristics remain insufficiently defined: the importance of preliminary heat treatment, the degree of purity of the specimen, the removal of internal stresses, and so on, are not taken into account to the proper extent. At the same time, Hume-Rothery quite rightly notes that it would be harmful to restrict the physicist by requiring him to investigate only, or primarily, technically important metals and alloys, whose properties are often marked by the greatest complexity. Imagine, he says, what the position of chemistry would have been if chemical investigations had from the very beginning been confined to the field of practically important compounds and alloys; how much this would have hindered the discovery of general laws.

It is very interesting that the author, in effect, approaches both in the preface to his book and in many places in the text the formulation of the necessity of a general plan for the development of science and technology in the field that interests him—something which, however, under the conditions of capitalist society, is, of course, doomed to remain in the realm of pious wishes.

Guided further by the fact that the successes of physical theory are at present confined chiefly to the field of the electrical and thermal properties of metals (which, however, is not entirely true, since in the very latest period the magnetic property has in fact also been added to them), and that on this basis the general theory of the metal will continue to develop, the author confines his exposition precisely to this field. Seeking to promote a rapprochement between theorists and practitioners, in the first part (167 pp.) the author gives a general survey of experimental data, guided in the selection of material to a considerable extent by its importance for theoretical investigation, while in the second part (205 pp.) he gives an exposition of the corresponding physical theories, accessible also to the non-specialist theoretician.

The first, experimental, part does not lay claim to any sort of completeness, but it gives a very clear general picture of the phenomena, successfully separating the essential from the secondary. Especially valuable is the attention devoted to the distinction between the properties of pure metals and those of various kinds of alloys, compounds, etc., data on which are almost entirely absent from ordinary physics textbooks and the like. The first three chapters are devoted to the electrical conductivity: a) of pure metals, b) of primary metallic solid solutions, c) of secondary solid solutions, and d) of intermetallic compounds; and also to the influence on electrical conductivity of temperature, pressure, deformations, heat treatment, etc. Here a solid solution is considered primary or secondary depending on whether its crystal lattice coincides with the lattice of the solvent metal or not. Next are considered thermal conductivity, thermoelectric properties, emission phenomena (photo-effect, thermionic emission, and the pulling out of electrons by strong fields), and finally some questions connected with contact potentials. The completeness and detail of the exposition generally decrease from the beginning to the end of this part. Unfortunately, there is no chapter on heat capacity, which is explained by reference to the availability of an exposition of the corresponding questions in textbooks of physical chemistry.

The second part of the book is devoted to the theories of the phenomena described in the first part. It gives a clear and thorough exposition of the classical theory of free electrons (Drude and Lorentz, 42 pp.) and then of a series of “intermediate theories,” which arose in such abundance before the key to the theory of metals was found in the new quantum mechanics. The author shows, very interestingly and instructively, how each of these theories—those of Thomson, Wien, Grüneisen, Bridgman, Hall, Lindemann—reflected some one definite aspect of the phenomena, the aggregate of which received its explanation, if not yet completely, then essentially in the new quantum theory. Still, these chapters, which are of historical interest, occupy a disproportionately large amount of space (42 pp.) in comparison with the space allotted to the exposition of the present state of the question (52 pp. + an appendix at the end of the book).

16 pp.). It is much to be regretted that in this part (the theory of Sommerfeld and Bloch), unlike the preceding ones, the author has refrained from a systematic exposition of the theory, confining himself for the most part to setting forth the physical side of the question and the principal results, while omitting most of the derivations. This undoubtedly benefits the clarity of the exposition and facilitates an initial acquaintance with the question, but, on the other hand, it is also beyond doubt that, for conscious work in the field of the physics of metals, the quickest possible mastery of the apparatus of the new theory is absolutely necessary. The author has likewise not taken into account the very latest phases in the development of the new theory, which is explained, of course, by its exceptionally rapid development, which only a specialist theoretician can follow.

Finally, in the concluding chapter there is a very interesting series of general remarks on the connection between the properties of metals and their position in the periodic system, to which the author devotes much attention both in the main text and also in the discussion of a number of empirical regularities (Lothar Meyer’s rule, etc.). However, rather too much space and attention is given to the quite complicated empirical dependence of the lattice constant on the atomic number of the element, which may perhaps have no theoretical significance at all.

In general, the book undoubtedly deserves a prompt translation into Russian and may be warmly recommended to all those interested in the physics of metals.

Iv. Tamm.