tions is concluded in this volume by an examination of the chemical action of burning-lenses and mirrors."
The volume is well printed in clear type, on good paper, and contains a fine steel portrait of Dr. Draper—much the best likeness of him that we have ever seen. It contains various woodcuts to illustrate experiments which the reader will find a useful accompaniment to the text.
Handbook of Modern Chemistry, Inorganic and Organic, for the Use of Students. By Charles Meymott Tidy, M. B., F. C. S. Philadelphia: Lindsay & Blakiston. Pp. 780. Price, $5.
This seems to be a very good practical treatise on chemistry, for the use of students in colleges and laboratories. It is well condensed, and judiciously classified. The author says concerning the work:
Sound: A Series of Simple, Entertaining, and Inexpensive Experiments in the Phenomena of Sound, for the Use of Students of Every Age. By A. M. Mayer, Professor of Physics in the Stevens Institute of Technology. New York: D. Appleton & Co. Pp. 181. With numerous Illustrations. Price, $1.
This volume is the second in Prof. Mayer's "Experimental Science Series for Beginners," the first volume of which, that on "Light," appeared a few months ago. The "Experimental Science Series," as the author states, originated in the earnest and honest desire to extend a knowledge of the art of experimenting, and to create a love of that noble art which has worked so much good in our generation. All attempts, however, to extend the knowledge of experimental science will fail unless these endeavors on the part of scientific men are seconded by our teachers; hence Prof. Mayer while writing these books, has been constantly actuated by the desire to assist teachers to become experimenters. "These little books," Prof. Mayer remarks in his preface, "will show how many really excellent experiments may be made with the outlay of a few dollars, a little mechanical skill, and patience. This last commodity neither I nor the school can furnish. The teacher is called on to supply this, and to give it as his share in the work of bringing the teaching of experimental science into our schools. when the teacher has once obtained the mastery over the experiments, he will never after be willing to teach without them; for, as an honest teacher, he will know that he cannot teach without them. Well-made experiments, the teacher's clear and simple language describing them, and a free use of the blackboard, on which are written the facts and laws which the experiments show—these make the best text-books for beginners in experimental science. Teach the pupil to read Nature in the language of experiment. Instruct him to guide with thoughtfulness the work of his hand, and with attention to receive the teachings of his eyes and. ears. Youths soon become enamored of work in which their own hands cause the various actions of Nature to appear before them, and they find a new delight in a kind of study in which they receive instruction through the doings of their hands instead of through the reading of books. The object of this second book of the series is to show how to make a connected series of experiments in sound. These experiments (a hundred and thirty in number) are to be made with the cheapest and simplest apparatus that the author has been able to devise, and they have been arranged so that one leads naturally to the making and understanding of the next." And it must be added that much of the apparatus needed for making the experiments is such that the student himself may construct it at trifling expense. So much for the method and principle of the work—a method which compels the student constantly to employ his own mental faculties of comparison, generalization, etc., and to be, in fact, a discoverer of the truths of science, not a mere passive recipient of instruction.