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420 the several processes. Quantities are given in English measures, followed by metric equivalents. In the part devoted to analysis are included blow-pipe tests and determinations of specific gravity. Several new examples of quantitative separation have been added in this edition, and volumetric analysis has been given a separate chapter. Ninety cuts illustrate the operations described. A dozen pages of technical information in regard to reagents are given, also tables of weights and measures, reactions, and solubilities, lists of salts for blow-pipe examination, etc. The uncut edges of the volume are rather inconsistent with the title, "Practical Chemistry."

are informed on page 7 of this book that "in 1877 Dr. H. Wilford Hall published a work on the 'Evolution of Sound,' in which he carefully considered, step by step, the present undulatory theory of sound, as elucidated by the distinguished authorities." It is furthermore said that Dr. Hall has shown that the current acoustical theory contains numerous fallacies, and, from the language adopted throughout the book, we should infer that it is shown to be childish, absurd, and wholly unworthy of credence. Dr. Mott avows his agreement with Dr. Hall, and he gave a lecture before the New York Academy of Sciences, December 8, 1884, stating Dr. Hall's objections to the present theory of sound, and this lecture constitutes the volume before us. Dr. Mott says that the work of exploding this theory has already been pretty well accomplished, and in his preface he gives the names of divers presidents of colleges, and professors thereof, from California to New Hampshire and South America, who have accepted "Dr. Hall's discovery," and abandoned as baseless and worthless the hitherto accepted wave theory of sound.

We can not here state Dr. Hall's case as re-expounded by Dr. Mott, but discharge our duty by informing all who are concerned about it where they can get instruction upon the subject. Nor have we formed any opinion, from having examined the arguments, whether the wave theory of sound has been exploded or not. There is getting to be such a free use of dynamite in these latter days among the supposed fundamentals and essentials of science, and long-established opinions seem so liable to sudden overthrow, that we are losing our interest in the operations. Perhaps the safest rule to follow in these revolutionary circumstances is to abide by long-tested principles until given up by those longest and most profoundly trained in the work of scientific investigation.

"Year-Book" is intended to serve as a convenient educational directory for the State of New York. It contains sketches of the county superintendents and county commissioners, and a list of the principals of village schools and academies arranged by counties. Every alternate leaf is left blank, for the insertion of notes, additions, and corrections.

is a collection of essays, which may be called critical or discursive, according to the mood of the reader, on "Carlyle," "Mr. Browning's Poetry," "Truth-Hunting," "Actors," "A Rogue's Memoirs," "The Via Media," and "Falstaff." They embody the "gratuitous opinions" of one who seems to be an independent thinker, forcibly and often very pungently expressed. Each essay has its own quality; that on "Falstaff" is a fund of humor; and they are all pleasant reading.

the multiplicity of popular treatises on astronomy, the author has thought there might still be room for a description of the sun, which, confining itself to a brief but careful enumeration of its phenomena, may be found serviceable in elementary instruction. The most recent discoveries are taken notice of.