"All the chemists in the country will enjoy its perusal, and many will seize upon it as a thing longed for. For, to those advanced students who have kept well abreast of the chemical tide, it offers a calm philosophy. To those others, youngest of the class, who have emerged from the schools since new methods have prevailed, it presents a generalization, drawing to its use all the data, the relations of which the newly-fledged fact-seeker may but dimly perceive without its aid.... To the old chemists, Prof. Cooke's treatise is like a message from beyond the mountain. They have heard of changes in the science; the clash of the battle of old and new theories has stirred them from afar. The tidings, too, had come that the old had given way; and little more than this they knew.... Prof. Cooke's 'New Chemistry' must do wide service in bringing to close sight the little known and the longed for.... As a philosophy it is elementary, but, as a book of science, ordinary readers will find it sufficiently advanced."-- _Utica Morning Herald._ VII. The Conservation of Energy. By BALFOUR STEWART, LL. D., F. R. S. _With an Appendix treating of the Vital and Mental Applications of the Doctrine._ 1 vol., 12mo. Cloth. Price, $1.50. "The author has succeeded in presenting the facts in a clear and satisfactory manner, using simple language and copious illustration in the presentation of facts and principles, confining himself, however, to the physical aspect of the subject. In the Appendix the operation of the principles in the spheres of life and mind is supplied by the essays of Professors Le Conte and Bain."--_Ohio Farmer._ "Prof. Stewart is one of the best known teachers in Owens College in Manchester. "The volume of THE INTERNATIONAL SCIENTIFIC SERIES now before us is an excellent illustration of the true method of teaching, and will well compare with Prof. Tyndall's charming little book in the same series on 'Forms of Water," with illustrations enough to make clear, but not to conceal his thoughts, in a style simple and brief."--_Christian Register, Boston._ "The writer has wonderful ability to compress much information into a few words. It is a rich treat to read such a book as this, when there is so much beauty and force combined with such simplicity."--_Eastern Press._ VIII. Animal Locomotion; Or, WALKING, SWIMMING, AND FLYING. _With a Dissertation on Aëronautics_. By J. BELL PETTIGREW, M. D., F. R. S., F. R. S. E., F. R. C. P. E. 1 vol., 12mo. Price, $1.75.