G. Tammann. Aggregatzustände. Leipzig, 1922.

Among the new literature that has reached us, one of the most interesting phenomena is represented by several monographs by the well-known Göttingen professor G. A. Tammann (formerly a professor in Russia, at Yuryev).

Tammann’s many years of work were devoted chiefly to the study of the transition of a substance from one state to another (from solid to liquid, from one solid crystalline modification to another, etc.). A series of most difficult investigations of a theoretical character made it possible to deepen and broaden this interesting field, and Tammann has found among scholars outstanding successors, among whom first place must be given to the talented American investigator Bridgman. Bridgman’s works marked an epoch not only by their achievements, but also by their methodology, which made it possible to operate with substances at pressures of thousands of atmospheres. At these pressures Bridgman succeeded in discovering astonishing forms of matter predicted by theory. For example, at enormous pressures water can form ice melting at about 80° above zero Celsius, etc. Tammann’s book brings together all the works, both his own and those of other investigators, and constitutes an outstanding phenomenon in the scientific literature.

P. Lazarev.