Nevertheless there is much in the book to be commended. The discussion of the metals and of the practical applications of chemistry is as a rule fairly satisfactory. A text on chemistry with preface dated January, 1909, however, should not contain the statement that helium has not been liquefied. ~VILLIAM RICPHERSON. Die Hdrte der festen Kijrper und ihre physikalisch-chemische Bedeutung. VICTOR POSCHL. Dresden: Theodore Steinkopff. 1909. ~v o . , 85 pp., 4 fig. Price,