From Introduction: "The present work is an attempt to collect all the available data referring to one important thermodynamic property and to supply sufficient discussion to make the results readily usable by metallurgists. In the study of chemical or metallurgical reactions two factors have predominant importance-the free energy of reaction and the speed of reaction. The subject of this publication is so closely allied to the former that may be well to consider briefly some of the uses to which free-energy data may be put."