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mained to be discovered. All of this has been adequately treated by Mme. Curie in the 1936 work, as well as the then very new discovery of artificial radioactivity. I t is truly a fitting close to a brilliant career that Mme. Curie should have lived from the epoch-making discovery of radium jointly with her husband and its isolation and study through a period of unabated activity and usefulness, including the establishment of a new radium institute, on don-n to the brilliant discovery of artificial radioactivity in her on-n laboratory by her daughter Mine. Irene Curie-Joliot and her husband, Frederic Joliot. The present volume will be most useful to all radioactivists and others working in the field of nuclear physics. I t is replete with illustrations and tables, as well as a long list of transformation constants. While literature references and a n index would have added to its value, i t is nevertheless indispensable in any library or t o any worker in atomic transmutation. S.C. LIND.
Gmelins Handbuch der anorganischen Chemie. 8 Auflage. Herausgegeben von der Deutschen Chemischen Gesellschaft. System-Kummer 22: Kalium. Lieferung 2. 26 X 18 cm.; pp. xi E( 217-514. Berlin: Verlag Chemie, 1937. Price: 31.50
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This section of the volume on potassium deals with the compounds with nitrogen (nitride, azide, amide, nitrohydroxylamite, dipotassium nitrite, hyponitrite, nitrite, and nitrate), the normal and acid fluorides, chloride, hypochlorite, chlorite, chlorate, and perchlorate. As usual, the physical and physicochemical properties are very completely dealt with. Since in some cases the methods of preparation and manufacture are closely similar t o those for the corresponding sodium compounds, these descriptions are abbreviated and reference is made t o the volume on sodium. The electrolytic technical method for the preparation of potassium chlorate is given in full; that for the perchlorate is abbreviated. Potassium nitride, K&, appears t o be formed by thermal decomposition of the azide. The colored solution of potassium in liquid ammonia is not colloidal. The nitrite (m.p. 41l'C.) is best prepared by the interaction of sodium nitrite and potassium carbonate in solution. T h e industrial preparation of potassium nitrate (used for gunpowder) from Chile nitre (sodium nitrate) began about 1850; the direct technical production from potassium chloride and nitric acid is no17 possible. The manufacture of potassium chloride is not described in this volume, although the properties of the salt and its solutions are very fully dealt with (122 pages). The thermal decomposition of potassium chlorate, both with and without catalysts, is well discussed; the catalytic activity of manganese dioxide is said t o be probably due to local heating. I t is interesting t o note that the formation of the perchlorate by electrolysis of solutions of chlorate, the modern industrial method, was observed by Stadion in 1816. The volume is one which niaint,ains the high standard of the whole work and contains a large amount of useful and interesting information very accurately and critically set out.
J. R.PARTISGTON. Lehrbuch der physikalischen Chemie. By I
