April 2, 1915] 



SCIENCE 



505 



broad subject of alternating current and alter- 

 nating current machinery. 



Ealph E. Lawrence 



Alternating Current Machinery. By Barr 

 and Archibald. The Macmillan Company. 

 496 pages and 16 plates. 

 The title of this book is too broad and some- 

 what misleading as only certain types of alter- 

 nating current machinery are considered, 

 namely: the transformer, the alternator, and 

 the rotary converter. No mention is made of 

 induction machines or of the synchronous 

 motor. The first chapters are devoted to com- 

 plex wave forms and their analysis and to the 

 properties of insulating materials used in 

 alternating current machinery. The insulation 

 of transformers and generators is also briefly 

 considered. The remaining chapters deal with 

 the theory and the design of the transformer, 

 the alternator and the rotary converter. Three 

 chapters are devoted to the transformer. Two 

 of these are given up to the consideration of 

 the fundamental principles, construction and 

 vector diagrams, while the third is confined 

 entirely to design. Some examples of diiier- 

 ent designs are included. Nine of the remain- 

 ing twelve chapters deal with the alternator. 

 The mechanical construction of alternators, 

 different types of armature windings, harmon- 

 ics caused by teeth, and the magnetic circuit 

 are discussed in the first of these chapters. 

 Several chapters are devoted to the discussion 

 of armature reaction, voltage regulation and 

 regulation tests. The eifect of a sudden short 

 circuit is also considered. The discussion of 

 the losses, efiicieney and heating of alternators 

 is also given considerable space. One chapter 

 is devoted to the parallel operation of alter- 

 nators. The last chapter on alternators, a 

 chapter of about forty pages, deals only with 

 design. Several examples of design are given. 

 The remaining three chapters are confined to 

 the rotary converter and take up the trans- 

 formation voltage ratio, armature reaction, 

 armature heating and output. Voltage regu- 

 lation, losses and efficiency, methods of start- 

 ing and parallel working are discussed. The 

 last chapter of the book deals entirely with 

 the design of converters, and as in the other 



chapters on design, examples of the design of 

 several converters are given. It is unfortunate 

 that the author has used clockwise and anti- 

 clockwise directions of rotation indiscrimi- 

 nately on the vector diagrams to indicate a 

 positive direction of rotation. Although an 

 arrow is added to each vector diagram to indi- 

 cate which direction of rotation has been 

 adopted, the lack of a definite convention in 

 this connection is apt to lead to confusion. 

 The book is in general well arranged and should 

 be a valuable one alike to the student and the 

 engineer. Ealph E. Lawrence 



SCIENTIFIC JOUMNALS AND ARTICLES 



The opening (January) number of volume 

 16 of the Transactions of the American Mathe- 

 matical Society contains the following papers : 



G. M. Green : " On the theory of curved sur- 

 faces, and canonical systems in projective dif- 

 ferential geometry." 



H. S. White: "The multitude of triad sys- 

 tems on 31 letters." 



G. A. Miller : " The 0-subgi-oup of a group." 



E. L. Moore : " On a set of postulates which 

 suffice to define a number-plane." 



W. C. Graustein : " The equivalence of com- 

 plex points, planes, lines with respect to real 

 motions and certain other groups of real 

 transformations." 



J. E. Eowe : " Invariants of the rational 

 plane quintic curve and of any rational curve 

 of odd order." 



M. G. Gaba: "A set of postulates for gen- 

 eral projective geometry." 



Virgil Snyder and F. E. Sharpe : " Certain 

 quartic surfaces belonging to infinite discon- 

 tinuous cremonian groups." 



Joseph Slepian : " The functions of a com- 

 plex variable defined by an ordinary differen- 

 tial equation of the first order and the first 



Arthur Eanum : " On the diif erential geom- 

 etry of ruled surfaces in 4-space and cyclic 

 surfaces in 3-space." 



The February number (Vol. 21, No. 5) of 

 the Bulletin of the American Mathematical 

 Society contains: Eeport of the eighth regu- 

 lar meeting of the Southwestern section, by 0. 



