Most students of gems will need to refer frequently to some good text-book of mineralogy. Although old, Dana's _Mineralogy_ is still a standard work. A newer book and one of a more popular nature is L. P. Gratacap's _The Popular Guide to Minerals_, D. Van Nostrand & Co., N. Y. Among larger and more expensive books on gems may be mentioned _Precious Stones_, by Dr. Max Bauer. This is an English translation of a German work which is a classic in its field. As it is now out of print in its English edition, a somewhat detailed account of its character may be of value to those who may be inclined to go to the effort to seek a copy at a public library or perhaps to purchase one through second-hand book stores. A popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewelers, etc., with an appendix on pearls and coral, by Dr. Max Bauer, Privy Councillor, professor in the Union of Marburg. Translated from the German by L. J. Spencer, M.A. (Cantab.), F.G.S., assistant in the mineral department of the British Museum. With twenty plates and ninety-four figures in the text. London, Chas. Griffin & Co., Ltd.: Phila., J. B. Lippincott Co., 1904. The book is a large one, xv + 627 pages, and is divided into three parts with an appendix on pearls and coral. Part I. deals with the general characters of precious stones. 1. Natural characters and occurrence. 2. Applications of Precious Stones. 3. Classification of Precious Stones. 106 pages. Part II. Systematic Description of Precious Stones, Diamond, Corundum Gems, Spinel, etc. 450 pages. Part III. Determination and Distinguishing of Precious Stones. 20 pages. Appendix, 26 pages. Pearls and Coral. Bauer is exhaustive in his descriptions of the more important precious stones and he also describes briefly very many little known and little used gem minerals. On forms of cutting he is old-fashioned. First 68 pages given to explanation of characters used in identifying stones. Good. On the Process of Cutting. Pages 79-87. Good account. More practical than most books give. Careful accounts of occurrence of precious stones with maps. Character of the occurrence of diamond in India, Brazil, and Africa, quite in detail. The student who wishes to master the subject of gems cannot afford to neglect Bauer. For those who read French, the latest, the most complete and thorough book on gems is Jean Escard's _Les Pierres Précieuses_, H. Dunod et E. Pinat, Paris, 1914. It is a large and finely illustrated work. The author has really outdone Bauer. The detail in regard to diamonds especially is very fine. Even the use of diamonds in mechanical ways is very completely gone into and also details in regard to cutting diamonds are very completely given. It is to be hoped that an English translation will soon become available.