Page:Popular Science Monthly Volume 7.djvu/255

Rh The work opens with a statement of the various unfavorable influences that tend to the enervation of the physical powers of parents; and this is followed by an outline of man's organization, development, and proper sustenance, and by an elucidation of the relations which exist between the vegetable and animal kingdoms, whence his subsistence is obtained. The book contains few cuts, and these are poorly made.

object of this book is to furnish a clear and easily-understood description of the principles, construction, and operation, of the locomotive-engine of the present day, a subject not concisely or adequately treated in any one similar book. It is intended not only as a hand-book for all classes of mechanics and railroad-men, but as a readable book of practical information for amateur engineers, students, and general readers. The headings of a few chapters taken at random are: "The Steam-Engine;" "Forces of Air and Steam;" "General Description of a Locomotive-Engine;" "Different Kinds of Locomotives;" "Accidents to Locomotives;" "Responsibility and Qualification of Locomotive Runners." The subjects presented are treated simply and plainly, in the form of question and answer, of which there are 563. The book is illustrated by 230 woodcuts and many plates.

new treatise on mechanics has for its object the establishment of strict precision in the meaning of dynamical terms, and the classification of physical quantities into elements and functions. It is written for students of mechanics, by a practical engineer; and the terms adopted in it are those used in the machine-shop, rejecting the ideal vocabulary heretofore used in text-books and colleges; thus the author rejects such terms as "efficiency of force," "working force," "quantity of motion," "mechanical power," "mechanical effect," "energy," etc., as having no definite meaning, or being redundant expressions meaning "force," "power," or "work." The first 56 pages treat of "Statics," and the next 221 pages are given to "Dynamics." A short chapter on the "Dynamics of Sound," a chapter on the "Mechanics of Astronomy," and an Appendix elucidating a duodenal system of arithmetic, measures, weights, and coins, complete the work, the whole of which is illustrated by 242 woodcuts.

contents of this neat little publication are designed particularly to enable mothers to understand and take care of the growth of children's teeth. The author first gives several illustrations with descriptions, showing the position of the teeth in the jaws, together with the usual time of appearance of the milk-set and permanent set of teeth. He then treats of the structure of the teeth, the changes they undergo, and the nutrition which they demand, the same as other parts of the body. The food must furnish bone-material as well as flesh-material. Phosphate of lime gives hardness to the teeth and bones, but it must be organized by a plant before it becomes fit food for an animal: "Artificial salts will not nourish the teeth by being taken as food; yet some persons have recommended that they be put into bread for that purpose." Other subjects are "Early Growth of the Teeth," "Infants' Teeth," "Dental Decay," "Children's Teeth," "The Six-Year Molars," "Plugging Teeth," "Effects of Medicine on the Teeth," "Diseases of the Teeth," "Extraction of Teeth," and "Artificial Teeth." The book is a good one, and will fully repay an attentive perusal.

contents of this volume are a course of lectures on physiology, delivered by Prof. Küss, at the Medical School of the University of Strasbourg; edited by Mathias Duval, M. D., of the Medical Faculty of Paris; and translated by Robert Amory, M. D., formerly Professor of Physiology at