“The chapters on Time and Action, Reaction Time, Thinking Time, Rhythmic Action, and Power and Will are most interesting. This book should be carefully read by every one who desires to be familiar with the advances made in the study of the mind, which advances, in the last twenty-five years, have been quite as striking and epoch-making as the strides made in the more material lines of knowledge.”--_Jour. Amer. Med. Ass’n._, Feb. 22, 1908. =25.=--=The World’s Gold.= By L. DE LAUNAY, Professor at the École Supérieure des Mines. Translated by Orlando Cyprian Williams. With an Introduction by Charles A. Conant, author of “History of Modern Banks of Issue,” etc. 8^o. M. de Launay is a professor of considerable repute not only in France, but among scientists throughout the world. In this work he traces the various uses and phases of gold; first its geology; secondly, its extraction; thirdly, its economic value. =26.=--=The Interpretation of Radium.= By FREDERICK SODDY, Lecturer in Physical Chemistry in the University of Glasgow. Third Edition, rewritten, with data brought down to 1912. 8^o With 33 Diagrams and Illustrations. As the application of the present-day interpretation of Radium (that it is an element undergoing spontaneous disintegration) is not confined to the physical sciences, but has a wide and general bearing upon our whole outlook on Nature, Mr. Soddy has presented the subject in non-technical language, so that the ideas involved are within reach of the lay reader. No effort has been spared to get to the root of the matter and to secure accuracy, so that the book should prove serviceable to other fields of science and investigation, as well as to the general public. =27.=--=The Social Evil.= With Special Reference to Conditions Existing in the City of New York. A Report Prepared in 1902 under the Direction of the Committee of Fifteen. Second Edition, Revised, with New Material Covering the Years 1902-1911. Edited by EDWIN R. A. SELIGMAN, LL.D., McVickar Professor of Political Economy in Columbia University. 8vo. A study that is far from being of merely local interest and application. The problem is considered in all its aspects and, for this purpose, reference has been made to conditions prevailing in other communities and to the different attempts foreign cities have made to regulate vice. =28.=--=Microbes and Toxins.= By ETIENNE BURNET, of the Pasteur Institute, Paris. With an Introduction by Élie Metchnikoff, Sub-Director of the Pasteur Institute, Paris. With about 71 Illustrations.