Scope of the tables.—These tables list the melting (congruent and incongruent) temperatures, boiling temperatures, and transition temperatures for the more important substances of interest to the geologist, the geochemist, and the petrologist. Eutectic and related data are given when the substance under discussion has been studied as a part of a binary or higher system. The aim in compiling the tables has been to describe the known thermal reactions of the compounds and the systems briefly, but in enough detail to be of use to an investigator in the field where extensive reference books are usually not available. Arrangement.—The entries are arranged alphabetically by chemical symbol (elements) or formula (compounds). Compounds composed of two or more oxides (except carbonates, sulfates, and other oxygen salts) are entered in the increasing alphabetical order of the constituent oxides. Mineralogical names are given following the nomenclature employed in Dana-Ford : Textbook of mineralogy (John Wiley and Sons Inc., New York).