a strong membership, and is doing a good deal of valuable work. The Society has permanent rooms at No. 11 East Fourteenth Street, which are open every evening from eight to ten o'clock. The "Journal of the American Chemical Society," like the "American Chemical Journal," is designed not for the outside world, but for those initiated into the mysterious technicalities of the science.
Treatise relative to the Testing of Water-Wheels and Machinery. With Various other Matters pertaining to Hydraulics. By James Emerson. Second edition. Springfield, Mass.: Weaver, Shipman & Co. Pp. 216.
This book has an interest for manufacturers using water-power. It seems that not long ago the testing of water wheels, with a view to determining their efficiency, was so difficult and expensive an operation, that the proprietors of new patent wheels of all kinds were tempted to make gross exaggerations of their effectiveness, because there were no ready means of getting at the actual facts. The author of this work accordingly addressed himself to the task of finding out some cheaper and more available means of making trustworthy measurements. This volume is chiefly devoted to that technical subject, and abounds in pictures of water wheels, and formidable tables. It also gives much information regarding other forms of mechanism.
An Outline of General Geology. With Copious References designed for the Use of both General and Special Students. By Theodore B. Comstock, B. Ag., B. S., of the Cornell University. Ithaca: University Press. Pp. 82.
This is a vade mecum for the use of geological students that has grown out of the author's syllabus of elementary lectures, to a mixed class of students, on economic geology and paleontology. It does not profess to be a text-book, but a help to study in connection with such works as Dana's "Manual of Geology" and Le Conte's "Elements of Geology." It gives summaries of important information and many useful references, blank leaves being freely inserted for convenience in making notes. Such a volume can not fail to facilitate the student's work in various ways.
Sewer-Gases, their Nature and Origin, and how to protect our Dwellings. By Adolfo de Varona, A. M., LL. B., M. D., etc. Brooklyn: "Eagle" Book Printing Department. 1879. Pp. 166. Price, 75 cents.
This little book contains much valuable information that every householder in our cities and towns should be familiar with. Many of the worst diseases are now believed to owe their origin to sewer or kindred emanations which find their way into houses, through defective planning and workmanship, both of which could be avoided if those most interested would take the trouble to inform themselves on the subject. In the present work the composition of sewer-gas, as determined by various competent analysts, is first considered; the relation of these gases to disease is next treated; then comes a description of the conditions under which sewer-gases are generated, the size, form, and construction of sewers, and the manner in which the sewer is connected with the house: this completes the first part, of the book. The second part is devoted to the subject of the protection of dwellings against the entrance of sewer-poison. The author confines himself to facts and their common-sense applications; and, although the information which he gives may probably be obtained elsewhere, it is here brought together in a brief and convenient form, and unencumbered with the trash that characterizes so many works on hygienic subjects. The style of binding and display on the cover are hardly in keeping with the contents of the book, but this maybe remedied in a future edition.
Reading as a Fine Art. By Ernest Legouvé, of the Academie Française. Translated from the Ninth Edition by Abby Langdon Alger. Boston: Roberts Brothers. Pp. 1)7. Price, 60 cents.
A very suggestive and useful little monograph on the subject of reading aloud. The writer believes in an art of reading, which is capable of being generally acquired, and he certainly makes out a very good case. He gives the rules for reading, and deals with the philosophy of declamation in a very lively and pleasant manner, which has been well rendered in an excellent translation.
