HARFORD, F. W. Metallurgy of Steel. With a section on the Mechanical treatment of Steel, by F. W. Hall. Revised edition. London, Charles Griffin & Co., 1905. 792 pp. 25_s._ This exhaustive treatise is the best of its kind. Abounds with valuable information on furnaces and their working, on the effects of different impurities in steel. On the shaping of steel mechanically it is the only complete treatise. This work deals, however, chiefly with English practice, while American practice is larger and more progressive. * * * * * HOWE, HENRY M. Iron, Steel and Other Alloys. 2d edition, slightly revised. Boston, A. Sauveur, 1906. 18+495 pp. $5.00. The best and most complete work on the modern theory of the constitution of steel by the highest living authority. Can be readily understood by any one having a slight knowledge of chemistry. In addition to the study of iron and steel as metals, brief but satisfactory chapters in manufacture are included. HOWE, HENRY M. Metallurgy of Steel. Vol. I. 4th edition. New York, Engineering and Mining Journal, 1890. 385 pp. $10.00. Still recognized the world over as the standard authority; every book written on its theme since 1890 builds upon this work as the source of highest reference. Devoted chiefly to the effects of different impurities, and of treatment, on steel. The crucible and Bessemer processes are described at some length. Not a work for general readers. * * * * * MELLOR, J. W. Crystallization of Iron and Steel: an Introduction to the Study of Metallography. London and New York, Longmans, Green & Co., 1905. 154 pp. 5_s_. $1.60. Reprinted lectures giving an excellent popular account of the constitution and nature of cast iron and steel. Includes right and wrong methods of annealing, hardening and tempering steel, and their microscopic examination. The information is presented in a terse and attractive style. Any reader of a scientific turn will find profit in this book. * * * * * SEXTON, A. HUMBOLDT. Outline of the Metallurgy of Iron and Steel. Manchester, Scientific Publishing Co., 1902. 16_s._ The best, because most recent of the good elementary text-books on iron and steel. It is behind the times in regard to American practice, but contains a great deal of important information, clearly expressed. Covers iron ores, their physics and chemistry, construction and working of the blast furnace, foundry practice, puddling, forging, the Bessemer, open hearth and crucible processes, special steels, the testing of steel and protection from corrosion. Its sketch of the structure and heat treatment or iron and steel is very incomplete. * * * * *