Page:Popular Science Monthly Volume 45.djvu/730

710 that "it is easier to learn the differential calculus than to follow a demonstration which attempts to avoid its use." Pneumatics and hydraulics have been included as divisions of hydrostatics, and there is a chapter on the mechanical theory of heat.

Dr. Daniel G. Brinton has reprinted from the Proceedings of the American Philosophical Society his account of Nagualism—a mystic cult that flourished in Mexico and Central America in the times of conquest and colonization (David McKay, Philadelphia, $1). The nagualists were of various tribes and languages, united in a powerful secret organization; they exercised necromantic powers and held occult doctrines. They were animated by an intense hatred of the Spanish explorers, and their one purpose was the destruction of the invaders and the annihilation of the government and religion introduced by them.

A recent bulletin of the United States National Museum is A Monograph of the Bats of North America, by Harrison Allen, M. D., being designed to take the place of the author's monograph on the same subject issued thirty years ago. The new work is made larger than the old by the addition of species and by elaboration of the descriptions. Thirty-eight plates, showing anatomical details, accompany the text.

A sketch of travel in California, by Rev. Dr. Charles A. Stoddard, has been published under the title Beyond the Rockies (Scribners, $1.50). Dr. Stoddard describes the fruit orchards, the wonderful climate, the big trees, the Yosemite Valley, the old missions, San Francisco and other Californian cities, etc., in a chatty and entertaining style. Incidents of travel are also mingled with the descriptions, and there are accounts of the scenery and stopping places in Texas, New Mexico, Arizona, Utah, and Colorado, which were passed through either in going or coming. The volume is copiously illustrated with photo-engravings of the places described.

A new translation of The Social Contract, of Jean Jacques Rousseau, with an introduction and notes by Prof. Edward L. Walter, has been issued (Putnam, $1.25). Students of political science will find in this book "the most striking statement of a theory destined to mold profoundly the history of nations," and will discover within it, also, "the weapons which are first sharpened and polished, and then directed against the whole framework of the modern state." The introduction reviews the political circumstances in which the treatise appeared, and the notes give historical facts concerning the persons and events referred to in the text, or references to books from which full information may be obtained.

In David T. Day's report on the Mineral Resources of the United States for 1892, the ninth of the series, the statistical tables of previous years are carried forward. Instead of chapters, the book is divided by mineral topics, which are so arranged as to bring kindred subjects together. The work is the result of a census conducted by the principal experts on each subject.

The Report of the Chief of the Weather Bureau for 1891-'92 is the first volume of the meteorological data published by the office as now constituted, and continues the series heretofore published by the War Department. The necessity of crowding two years' work into one report has compelled condensation by the omission of the detailed hourly and twice daily observations; but this omission is partly supplied on the daily weather maps. Tables of monthly and annual normal pressure, temperature, and precipitation are given. A description of the instrumental equipment of observing stations by Prof. C. F. Marvin, and a report by Prof. Cleveland Abbe on the instrumental corrections, methods of reduction, and the probable resulting accuracy of the observations and the means, add much to the value of the volume. Mark W. Harrington, chief of the bureau.

The Commissioner of Labor of the United States publishes a special report on Compulsory Insurance in Germany, which has been prepared at his request by Mr. John Graham Brooks, after residing in Germany and making a careful and broad study of the subject and all the circumstances surrounding. The author was commissioned to collect all the official information available with reference to the system, and to ascertain in all legitimate ways its real workings, its effect upon labor and the workingman, and its general tendencies. Neither approving nor condemning the system, Mr. Brooks has given the