Page:Popular Science Monthly Volume 50.djvu/582

564 in his preface, "the transformer was born, and in one decade it has attained its maturity. During its development it has been the subject of much investigation and study and has been carefully considered from every standpoint, so that complete novelty of treatment is now scarcely looked for—in fact, would not be desirable. There is a demand, however, for a united and logical exposition of the principles involved. To this end the writer has turned his efforts and contributes the following pages." The subject has been kept within well-defined limits. Thus, while systems of distribution are briefly reviewed as bearing directly upon the principles of the apparatus, the subjects of fuel and boilers and of central-station operation have been excluded as irrelevant. The theory of the alternator is given in brief. The author has taken especial pains to make his book tend toward uniformity rather than diversity in notation. The C. G. S. system has been used for expressing magnetic quantities for the reason that international agreement as to names for magnetic units has not yet been secured. In elucidating the principles set forth, two hundred and fifty diagrams and other cuts are used, and the volume is adequately indexed.

The School Algebra, by Emerson E. White (American Book Company, $1), has among its distinctive features the early introduction of the equation, the application of arithmetical approaches to algebraic processes and principles, and the immediate application of facts and principles in simple exercises. Processes that do not appear generally in school algebras are the multiplication and division of polynomials by detached coefficients; a general method of factoring trinomials; the solution of quadratic equations by factoring; and in the closing chapters a simple treatment of undetermined coefficients, determinants, and curve tracing.

The Romance of Industry and Invention, consisting of articles selected by Robert Cochrane from the pages of Chambers's Journal, with additions, is a nice book for Scotch and English readers, but we fail to see why it should come to America (Lippincott, $1.25). One would suppose from reading it that the biography of the Englishman Wedgwood was the whole history of the pottery industry; that America has no cotton mills, but only serves with India and Egypt to furnish raw material to England; that only the gold fields in British possessions are worth more than a mere allusion, while Ericsson's Monitor with its revolving turret never existed. On the other hand, it does appear that the chief inventors of sewing machines were Americans; more credit is given to Morse for the telegraph and Field for the Atlantic cable than is usual in British popular writings; while Bell and Edison can not be hidden in any account of their inventions; and there is actually a distinct admission that "from the time of their last war with us down to within a quarter of a century ago our Yankee neighbors generally seemed to be a little ahead of this country in maritime matters."

A graphic lesson in The Effects of Erosion, due to forest destruction, is afforded in a chart recently issued by the United States Department of Agriculture. It bears three colored pictures showing respectively How the Farm is Lost, How the Farm is Regained, and How the Farm is Retained, each accompanied by a few lines of explanation and counsel.

In August, 1896, the first number of The Hypnotic Magazine appeared (Psychic Publishing Company, Chicago, $2.50 a year). It is edited by Sydney Flower and is devoted to "an investigation of the science of hypnotism, its uses and abuses, and its therapeutic possibilities." Among the articles in the first number is a report by Herbert A. Parkyn, M. D., of cases treated in the daily clinic conducted by him in Chicago. Other contributors are Charles G. Davis, M. D., W. L. Stevenson, M. D., and W. X, Sudduth, M. D. The contributors, although showing the confidence of enthusiasts, succeed in avoiding the extravagances that sometimes make hypnotism ridiculous, while the tone of the Introduction and other editorial expressions is modest and enlightened.

Visible Speech is a system of speech notation which uses symbols designed to suggest the proper positions of the vocal organs. It has been presented to the public by its author. Prof Alexander Melville Bell, in books adapted to a variety of needs. One