BIBLIOGRAPHY*

RUDOLF SEWIG. Objektive Photometrie. B., Springer, 1935, VII 1935, 140 Abb. Mk. 17.50

R. SEWIG. Objective Photometry

Sewig’s book is divided into four parts. The first part describes various receivers of radiant energy used for measurements. This part describes thermoelements, bolometers, photocells, and light-sensitive resistances. Here data are given that characterize the sensitivity, inertia, and design features of the indicated instruments of the newest types, produced by various firms.

The second part is devoted to electrical measuring instruments used to measure very small currents and potentials. Here electrometers and galvanometers of recent designs are described, with indication of sensitivity and inertia. In addition, oscillographs are mentioned very briefly. Considerable space is devoted to both optical and electrical methods of amplifying the currents being measured.

In the third part a brief survey is given of optical auxiliary instruments used in measurements of radiant energy. This part describes light filters, serving to isolate individual regions of the spectrum, and spectral instruments: spectrographs, monochromators. It must be said that these questions are presented quite unsatisfactorily. There are no data on the degree of monochromaticity provided by individual instruments and filters. Moreover, the most commonly used monochromators are not indicated, and alongside them spectroscopes, which are not used in measurements, are described. In this same section some space is devoted to light sources, and the information given is chiefly of a purely design character.

Finally, the fourth part, bearing the same title as the whole book, is devoted to the description of objective photometers. Since all the separate component parts of objective photometers were described in the preceding chapters, here the author confines himself to a description of designs and general schemes. The newest objective pyrometers and actinometers are described, followed by spectrophotometers and colorimeters.

A separate section gives a brief survey of various systems of microphotometers. Some bewilderment is caused by the absence of a diagram of the Zeiss self-recording photoelectric microphotometer, which is one of the most widespread instruments of this type. At the same time, a drawing is given of the very obsolete Kross microphotometer. The fourth part ends with a description of numerous photometric photometers. A colossal number of objective luxmeters, reflexometers, and other photometers produced by various firms are cited. However, the author confines himself to giving data from firms’ catalogues without any critical evaluation of them. The accuracy of a whole series of devices raises serious doubts.

At the end of the book there is a list of works from the last 4 years on objective photometry (180 titles).

* Based on materials of the Critical-Bibliographic Institute.

The general character of the book is designed to enable the reader to select a ready-made instrument for measuring radiant energy that corresponds to the conditions of his measurements. The author even indicates the price of the instruments.

If, however, the reader needs to construct the instrument himself, he will find little in this book that is useful to him.

For the Soviet reader the book may serve as a reference work (not in all parts reliable) for extracts of apparatus from abroad. Thus the book is of interest to a comparatively narrow circle of specialists, and there is no point in translating it.

V. Fabrikant