THE recent development of physical chemistry may be said to date from the year 1887. The fundamental ideas on which the modern superstructure rests had been conceived and even published before that time; but though the phase rule of Gibbs, the osmotic pressure theory of van't Hoff and the electrolytic dissociation theory of Arrhenius had all appeared in print, they were buried in the little-known transactions of minor academies, and so escaped general notice. It is undoubtedly to Ostwald that the popularisation of physical chemistry is due. Himself an unflagging worker in the field, he gathered together and systematised the work done by his predecessors in the Lehrbuch der allgemeinen Chemie, which was completed in 1886. In 1887 the new era began with the establishment of his Zeitschrift für physikalische Chemie. To the first volume of this journal, van't Hoff and Arrhenius contributed succinct accounts of those theories which have since so largely inspired and dominated physicochemical work. The extent of this work may be gathered from the fact that of the Zeitschrift thirty-four volumes have now been published, each volume containing on the average nearly 750 pages. The Journal of Physical Chemistry. Edited by Wilder D. Bancroft Joseph E. Trevor. (Cornell University, Ithaca, New York.)