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THE POPULAR SCIENCE MONTHLY 



conduits are considered. Long-distance lines, 

 the various kinds of wire suitable for tele- 

 phone use, insulators, and the exchange sys- 

 tem are among the subjects treated of in the 

 part of the book devoted to the mechanical 

 construction of telephone lines. A chapter 

 upon the propagation of energy, in which a 

 brief account is given of the modern view of 

 electric currents, precedes the consideration 

 of the electrical properties of the telephone 

 line. Among the subjects discussed in this 

 portion of the work are self-induction, inter- 

 ference from outside sources — such as air 

 and earth currents — telegraphic induction 

 and induction from electric lighting and rail- 

 way circuits, properties of metallic circuits 

 and of cables. The work is written for the 

 practical telephone constructor and for stu- 

 dents, and will doubtless prove a valuable 

 work of reference. 



HOW TO MANAGE THE DYNAMO. By S. R. 



Bottone. New York and London : Mac- 

 millan & Co., 1893. Pp. 63. Price, 60 

 cents. 



This little manual is addressed to those 

 who have the care of dynamos, and is clearly 

 and directly written and free from all techni- 

 calities. Instructions are given as to proper- 

 ly setting the machine so as to avoid vibra- 

 tion, and the different parts — the field mag- 

 nets, armature, and commutator — are briefly 

 described, and instruction given for their 

 proper care. Simple methods of determin- 

 ing and locating leaks are also given. The 

 book closes with a list of the chief electrical 

 terms, and is provided with an index. 



The Transmitted Word. By W. J. Keenan 

 and James Riley. Boston: Dorchester 

 Printing Co., 1893. Pp. 113. Price, V5 

 cents. 



The authors of this essay state its pur- 

 pose in the preface as follows : 



" To know somewhat of the application of 

 this great force, which man has discovered 

 and called electricity, these pages are writ- 

 ten. They are free of all technical terms. 

 Simplicity has been the constant aim. The 

 student's text-book on electricity has been 

 written. The public's book has not been 

 written. And, as we are taught to know 

 ourselves, so should we know the forces that 

 surround us. Especially so if we use these 

 forces. Every subscriber of the telephone 



should know the rudiments of its action- 

 This is why this book is put forward. It is 

 intended as a primer in telephonic and other 

 kindred instruction. . . ." 



This purpose of the authors is laudable 

 enough, and, if it had been adhered to, they 

 might possibly have produced a useful book. 

 Their real aim seems, however, to have been 

 to give an exhibition of what they probably 

 regard as fine writing, using the telephone as 

 an excuse for their literary effort. The book 

 is written throughout in the most approved 

 style of sopbomoric composition, and con- 

 tains very little real information about the 

 telephone. The reader who had no previous 

 knowledge of the subject would have a hard 

 time indeed in trying to get any clear ideas 

 of the Blake transmitter or induction from 

 the description of the authors. The book 

 has, however, one great merit. It is short. 



Man and the State. Lectures and Discus- 

 sions before the Brooklyn Ethical Associa- 

 tion. New York : D. Appleton & Co. 

 1892. Pp. 558. Price, $2. 



This volume of lectures and addresses 

 before the Brooklyn Ethical Society is de- 

 voted especially to subjects of current polit- 

 ical discussion, such as the tariff, the mone- 

 tary question, the negro problem, the gov- 

 ernment of cities, and kindred subjects. To 

 those who are familiar with the discussions 

 before the society, or who have become ac- 

 quainted with the character of the work 

 from its previous publications, no word of 

 commendation of the quality of these papers 

 is necessary. The addresses are thoughtful 

 and serious discussions of current political 

 and economic questions, and can not fail to 

 be welcomed by all who take an intelligent 

 interest in public affairs. It would be im- 

 practicable to attempt to give here either a 

 resume or criticism of the dozen and a half 

 addresses which compose the volume, though 

 some features of interest may be briefly in- 

 dicated. The volume was published last 

 year, previous to the presidential election, 

 and the addresses were selected chiefly with 

 reference to the questions before the coun- 

 try during the campaign. We have there- 

 fore a discussion of the tariff from the side 

 of both protection and free trade, a plea 

 for sound money, and a defense of each 

 of the great political parties. The free- 



