Septembeb 13, 1901.] 



SCIENCE. 



411 



Assisted by Hobart Mason, B.S. 12 mo. 



Pp. 281. Price, $2.50, net. 



The appearance of a promising new text- 

 book on a subject relating to electrical engineer- 

 ing in any of its phases is a matter of much 

 interest in the engineering schools; but Dr. Shel- 

 don's book on ' Dynamo Electric Machinery ' 

 may justly receive special attention on account 

 of the author's experience as a teacher and 

 writer, his reputation for vigor, and the evi- 

 dent care with which he has constructed the 

 book. Covering a field in which there are 

 many books, the new comer finds an ample de- 

 mand which is unfulfilled ; for none of the 

 older books are completely satisfactory as text- 

 books and few are more successful as reference 

 books. The demand for a really successful 

 college text-book on applied electromagnetism 

 and the construction of dynamos is therefore 

 large and crying, and the new comer was as- 

 sured of a certain effusiveness of welcome from 

 technical college circles. 



It then becomes a matter of interest to 

 scrutinize the book and learn whether it fulfills 

 those important requirements that are yet un- 

 fulfilled by existing literature ; and it is a satis- 

 faction to say that in many respects it bears 

 the scrutiny well. In order of treatment and 

 clearness of exposition the book is admirable, 

 as it also is in typography and in much of the 

 illustrative matter. The book has character- 

 istics which are excellent in one designed for 

 classes of trained mechanics, and perhaps the 

 shorter and in some respects more superficial 

 ' information courses ' of instruction, which are 

 given in our engineering schools to classes of 

 men who are not following the professional 

 course in electrical engineering and for whom 

 the allotment of time to the subject of dynamos 

 is insufficient for the most approved scientific 

 instruction. 



Dr. Sheldon's book was thus used during the 

 past year in the University of Wisconsin as the 

 text-book for a short course of study in dy- 

 namos required of mechanical engineering 

 students. In this place the book proved suc- 

 cessful, though several predecessors that pre- 

 sumably occupy a similar field had failed to 

 give satisfaction. It is also expected that Dr. 

 Sheldon's book will give good results in the 



better classes of the Summer School for Ap- 

 prentices and Artisans which has just completed 

 its first session at the University of Wisconsin. 



For the longer course in applied electromag- 

 netism and the construction of dynamos that 

 should be presented to the men pursuing a 

 college course in electrical engineering, this 

 book does not appear to be so well adapted. 

 Such a course should deal in principles, prin- 

 ciples, principles ; and it should be remembered 

 that good results involve much labor on the 

 part of the student, however much interested 

 he may be. In the small compass of Dr. Shel- 

 don's book, so much space is occupied by de- 

 scriptions and illustrations of the commercial 

 apparatus of the day that the principles of 

 electromagnetism and the modes of their appli- 

 cation cannot be adequately treated. 



We have no text-book on this subject which 

 satisfactorily meets the requirements of a 

 thorough treatise for the ' electrical engineering 

 students ' of our colleges, and we may justly 

 say that it is better to use as a syllabus for 

 these classes some book which deals sensibly 

 and with reasonable adequacy in the theory of 

 electromagnetism, than to use a book like Dr. 

 Sheldon's which is of the so-called 'more 

 practical ' character. This choice of the pref- 

 erable plan casts much labor on the teacher ; 

 but where the best teaching is the object, labor 

 cannot be shirked. 



To meet the requirements of the college 

 classes to which I refer, a book is required of 

 much greater scope than Sheldon's and much 

 greater volume. One may doubt whether 

 Sheldon's book was seriously planned for such 

 classes, as the author's intention is stated in 

 his preface to be to write a book ' to be used 

 primarily in connection with instruction on 

 courses of electrical engineering in institutions 

 for technical education ' ; and also to meet the 

 wants of ' the general reader, who is seriously 

 looking for information concerning dynamo electric 

 inachinery of the types discussed, * * *.' The 

 object which I have set forth in italics has been 

 well attained. It is obviously impossible to 

 attain this object, and also to meet the require- 

 ments of extended scientific instruction, in the 

 subject of this book, all within the covers of a 

 duodecimo volume of 281 pages. 



