The author has, on the whole, successfully coped with the difficult and complex task which he set himself, and his book is indeed a valuable aid both for the beginning researcher and for the engineer.

N. Papaleksi.

V. V. Svyatoslavsky. 1) On the calorimetric bomb and on a standard in the thermochemistry of organic compounds. 2) Diazo compounds. A thermochemical investigation.

[Doctoral dissertation] Separate offprint from the Transactions of the Society for the Advancement of the Successes of the Experimental Sciences and Their Practical Applications, named after Kh. S. Ledentsov. Supplement No. 7—1917. pp. 1—361. Price 2 rubles.

The present investigation by Svyatoslavsky is divided into two parts: the first—methodological—in which he describes an adiabatic calorimeter that makes it possible, by continuous change of the temperature of the surrounding space in which the calorimeter with the combustion bomb is placed, to eliminate errors due to cooling of the calorimeter. In this part Svyatoslavsky remains entirely on the ground of the old Berthelot methodology and makes no use at all of the remarkably ingenious procedures developed by Nernst and his school.

Here, in the first part, Svyatoslavsky gives a detailed determination of a standard in the thermochemistry of organic compounds according to the data of Fischer and Jaeger and his own, using benzoic acid for this purpose.

The second part gives the methodology and the results of thermochemical investigations in the field of diazo compounds and contains general considerations on the structure of diazo compounds, based on the author’s thermochemical investigations.

I. Lazarev.

S. E. Sheppard. Photo Chemistry (Text-Books of Physical Chemistry edited by Sir William Ramsay). London, New-York, Bombay and Calcutta—1914. (461 pages).

In recent times quite a considerable number of textbooks on photochemistry have appeared in the German language; Sheppard’s book is the first book written in English.

In the first chapter Sheppard gives a brief history of the doctrine of light and of its chemical actions; in the second chapter the laws and methods of optical observations are set forth. Further, the units of light intensity are given, with the English units described in detail and the methods of photometry and spectrophotometry indicated. Chapter three treats the laws of radiation, giving data on the black body and describing methods for determining temperature by optical means. In chapter four the question of ...