in a text a thermcdynamics is the extensive discussion of phase rule applications. All the topics considered in the better works on the subject are taken up, usually in considerable detail. Especially commendable is the treatment of deductions from the first and second laws, thermodynamic functions and equilibrium, chemical potentials, electromotive force and the free energy of cell reactions, and so forth. Not usually found in other comparable texts is a chapter on special cases of ionic equilibria. Unusual attention is paid to critical phenomena. I n 1920 the author stated, "It has been my endeavor to write a book which, in addition t o being accurate, logical, and sufficiently rigorous, will furnish the student with numerous examples of the application of the principles of the science." The latest edition certainly realizes that aim. Quite obvious t o any reader is the meticulous care with which the author defines his terms, e. 8.. in his distinction between the various activity coefficients, between electrical potential and electromotive force, and so forth. His derivations are quite detailed, seldom requiring the user t o fill in huge gaps. The svmhols used are those common t o American conventions. -~ Chrmiral ~mentialis preferred generally in lieu of partial mulal free merm. A rompnct talmlation of all symbols should, however, have brcn included. l
