…of particular interest are Vvedenskii’s results, published here for the first time; he showed that, in very thin wires, the retarding influence of Foucault currents on magnetization disappears, and there remains only a lag caused by the internal crystalline structure of the substance, not by its dimensions and shape; namely, in iron the magnetism falls to half its initial value in a time from \(0.4\cdot 10^{-6}\) sec. to \(2.2\cdot 10^{-5}\) sec., depending on the magnitude of the magnetization. These conclusions provide rich material for the theory of magnetization.

Not having the opportunity to dwell in greater detail, let us point out that a number of interesting works were printed in various issues of both journals (for example, Nikitin’s work on the influence of metallic screens on the period and energy of oscillatory circuits, Bazhenov’s work on directional radio-telegraphy, etc.).

S. Rzhevkin.

Ch. Boys. Soap Bubbles. Lectures on capillarity and capillary phenomena, delivered before a youthful audience. Translated by V. M. Pozner, edited by A. P. Afanas’ev. Scientific Book Publishing House, Petrograd, 1919, pp. 190 + 1 unnumbered.

“Soap Bubbles” by Boys hardly need any special recommendation. This little book long ago won universal recognition and affection. It may rightly be classed among that classic collection of exemplary popular books on natural science which includes Faraday’s “History of a Candle,” Tyndall’s lectures, and so on. Nor is it for nothing that the book has been translated into German, French, Polish, and Russian—not for nothing, to use Boys’s own picturesque expression, that some two tons of his bubbles have flown around the world.

That is why the appearance of a new Russian translation of this remarkable little book must be welcomed. As for the edition itself, it deserves approval: the translation is good, and the appearance quite satisfactory. In any case, to achieve anything better, while keeping the price to a minimum, would perhaps have been impossible under the present difficult conditions of printing. The color plate appended to the book is executed quite poorly.

E. Shpol’skii.

Bulletin of Roentgenology and Radiology. Physico-Technical Section. Publication of the State Roentgenological and Radiological Institute. Vol. I, Issues 1, II, and III, Petrograd, 1919.

Until now, scientific and technical works in the field of roentgenology have been scattered through literature partly of a physical, partly of a technical, and even of a medical character. The task of the publication under review…