Molecular and ionic interactions in dielectrics

Two years ago, Powles, in this chapter suggested that there were too many theories, rather than too few experiments. This statement is, unfortunately, even more justified now, and a really comprehensive review of the whole field of dielectric theory in the light of experimental results is long overdue. This would be a herculean task, and most authorities who have the ability to carry out such a valuable project have their programs too crowded already. C. P. Smyth, in his new book, “Dielectric Behaviour and Structure” which is reviewed later in this chapter has made several such comparisons, but they are by no means exhaustive. After consideration of the Debye, Onsager and Kirkwood equations, he presents a further five pages of “Other Equations” with an average of more than two theories a page: then there are a further twelve pages relating to “Solvent Effects”, some of which are inseparable from the general theory. At the end of the first chapter there is an excellent summary, which is all too short, of the conditions under which the better-known equations may be applied. The young chemist or physicist would find it a hard task to fight his way through this introductory chapter and the molecular engineer, for whom the book is also intended would probably wish that he had taken a more classical course. And yet, Smyth1s first chapter is undoubtedly one of the best brief text book presentations so far; the fault, if there be one, lies with the subject, not with the author. Only the rheologists have a wider range of phenomena to account for!