THIS is the latest edition of a work which has been known in Germany for ten years, and of which the author is the Director of the Photochemical Laboratory of the Imperial Technical High School in Berlin. The existence of such a post as that occupied by Dr. Vogel in one of the foremost technical schools of Germany is as much an indication of the advanced state of technical education in that country as the non-existence of such specialists in the technical schools of this country is a sign of our comparatively backward condition in the field of chemical technology. The subjects comprised under this heading are so wide in their range and so difficult to grasp, excepting by actual personal contact with the chemical industries, that no instruction likely to be of any great value to those preparing for, or engaged in, the latter can be given, unless the instructor has this qualification. Nor can the student properly avail himself of the instruction thus offered, unless he on his part is well grounded in the general principles of the science which underlies his subject. When such a ground-work has been laid, and the student thus equipped is passed on to the specialist, the result is a chemical technologist who is likely to be of real use to his country. The Germans have realized this long ago—the machinery exists both for laying the foundation and for raising the superstructure of specialized knowledge. In this country, so far as chemical technology is concerned, we have not yet advanced very much beyond the stage of furnishing the appliances for the general training-the real technical or special training has been allowed to take care of itself, and the student is supposed to have finished his education at the time when he ought really to be beginning it. Handbuch der Photographie. Part I. Fourth Edition. By Prof. Dr. H. W. Vogel. (Berlin: Robert Oppenheim, 1890.)