Gmelins handbuch der anorganischen chemie. Edited by the German Chemical Society. 8th edition. System number 21: Sodium. Pp. xxiii + 992. Berlin: Verlag Chemie, 1928. 150 rm.; subscription, 118 rm. (post free). System number 31; Radium and its Isotopes. Pp. xviii + 80. Berlin: Verlag Chemie, 1928. 15 rm.; subscription, 12 rm. (post free).