��THE POPULAR SCIENCE MONTHLY,
��such class, both original and selected from foreign journals, are, as a rule, written by experts, by men who have made special study of the points they are discussing, or have had experience in the application of them. It also pays considerable attention to topics of a more general scientific charac- ter, and gives much withal that commends itself to persons who are not specialists or professionally informed, but who have an intelligent interest in the progress of the departments to which it is devoted.
Proposed Plan for a Sewerage System, and for the disposal of the sewage of the City of Providence. By Samuel M. Gray, City Engineer. Pp. 146, with Plans and Maps.
City Engineer Gray was deputed by the City Council of Providence, a year ago, to proceed with his assistant to Europe to in- vestigate the various plans in practical op- eration for the disposition and utilization of sewage, and upon the information thus obtained to report a plan for adoption in that city. The list of cities and works he visited, in England, Wales, Holland, France, and Germany wherever, in fact, important sewerage-works have been undertaken, or systems for the disposition of sewage have been tried, or are under trial shows that his inspection was a busy one. In the plan which he has devised, with the aid of these observations, he has had in view the prin- ciple which is in reality the Hamlet of the question, but is too often left out, that " no system of sewerage is complete which fails to dispose of the sewage so as to avoid its causing a nuisance." The report embodies a large mass of information, presented with commendable brevity. After an historical review of the subject, the several systems for disposing of sewage are considered as to their general principles and specifically. Among these are the systems of sewage in- terception, or dry-sewage systems, the pneu- matic systems (Licrnur, Berlier, and Shone) ; the water-carriage system ; and the systems of disposal by irrigation and precipitation; with a comparison of the different methods of purifying sewage. Although prepared only for a special object, the report might, in the absence of any other comprehensive work, serve as a general manual of the sub- ject.
��Tables, Meteorological and Physical. By Arnold Guyot. Fourth edition, re- vised and enlarged. Edited by William Libbey, Jr. Washington: Smithsonian Institution. Pp. 738.
Professor Gdyot's original work, pub- lished in 1852, was the first of the series of " Tables of Constants," to which the Smith- sonian Institution is gradually making im- portant contributions, and has proved, by the demand which arose for it, to be the one of the series that has met the most general public want. A second revised edition was published in 1857, in which the tables were so enlarged as to extend the volume of the book from two hundred and twelve to more than six hundred pages. A third edition was published in 1879, with further amendments. The author began the revision for this fourth edition in 1879, but was met with delays, and died before completing the work, which was left for his assistant and successor in his college pro- fessorship to finish. The contents consist of tables comparing the different thermo- metrical scales, with reductions from one to another; hygrometrical tables, with tables for the conversion of metrical hygrometric measures into others ; barometrical tables ; hypsometrical tables ; geographical meas- ures, in which means are given for reducing the measures of all countries from one to another ; meteorological corrections ; and " Miscellaneous Tables useful in Terrestrial Physics and Meteorology." The whole con- stitute a valuable reference book.
The Ornithologist and Oologist, Vol. IX. 1S84. Pawtucket, II. I. : Frank B. Web- ster, publisher. Twelve Numbers. Pp. 152. Price, $1.50 a year; 15 cents a number.
As is implied in its title, this is a maga- zine devoted to birds, their nests, and eggs. It is beautifully printed, and is sustained by a corps of competent and enthusiastic con- tributors, who record in it their daily, week- ly, monthly, yearly, or occasional observa- tions, on these the most attractive of man's companions on the earth. It is a pity that so many of them consider it an indispensa- ble preliminary to the observations to shoot the birds or steal their eggs. In the pres- ent state of science, these things, when they are done, are unnecessary in nine cases OHt