H. BRUINING. Over de emissie van secundaire electronen door vaste stoffen, Leiden, 1938.

G. BRUINING, On the Emission of Secondary Electrons by Solids, 1938, p. 119, fig. 46.

This book is the author’s dissertation in Dutch, in which are systematically set forth both his works already published in the journal Physica in 1936–1938 and a number of still unpublished measurements. All this, of course, leaves a definite imprint on the book, and, in particular, although the author gives at the end of the article a list of works comprising 152 titles, he devotes only a very modest place to their exposition. The book consists of the following chapters: 1. Introduction. 2. Apparatus and methods of measurement. 3. Secondary emission of metals. 4. Absorption of secondary electrons. 5. Secondary emission of compounds. 6. Influence of adsorbed ions and atoms on secondary emission. 7. Influence of the macroscopic structure of the surface (A. Conductors and B. Dielectrics) on secondary emission. Finally, at the end there are summaries in English and a bibliographic index.

The main and most interesting part of this book is the presentation of the author’s experimental work, carried out by him in the Philips laboratory and standing at a very high level of experimental technique. As an example of this one may first of all point to the works connected with investigations of pure metals, in particular where it was shown that truly perfectly pure alkali metals give a comparatively small secondary emission.

Of considerable interest are also the author’s works on the investigation of emission from surfaces with a porous structure, etc. If in these directions the author has done substantial work, then much more modest, chiefly from the point of view of systematic treatment, are his works on complex surfaces, for vacuum tubes very important; the most important works in practice on surfaces of this kind were carried out by Soviet investigators. In the author’s book we find here only separate unsystematic measurements, although some of them are very interesting, as, for example, the emission of alkali-halide compounds (which, unfortunately, are described very briefly without indicating the method), emission of magnesium oxide, etc. Then the book sets forth some of the author’s views on the nature of secondary emission, which must be regarded as debatable, and in one place (Fig. 29a for the potential scheme of alkali-halide compounds) even incorrect. Nevertheless, this book remains a pleasant impression of a large range of very good experimental work, which can undoubtedly contribute much to the understanding of the phenomenon of secondary-electron emission.

N. Morgulis, Kiev