of crystals; the conditions of growth are relat­ ed to the morphological characteristics of the growing faces, and the relationship between the habit of the crystals and the oomposi­ tion and constitution of the solutions is considered. A fair number of articles are concerned with the crystalliza­ tion of new compounds, most of which have now been synthesized under hydrothermal conditions for the very first time; these in­ clude ternary chalcohalides of composition AVBvIVVII. zirconates, lithium silicates, and germanates. The collection also contains a description of the apparatus used for precision measurements at high temperatures and pres­ sures. We hope that this publication will present a better idea of the special characteristics of the hydrothermal method of synthes­ izing and .growing crystals, and will prove useful to all those in­ terested in this field of knowledge.