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XXIX. Notices respecting New Boohs. 



Dynamo-Electric Machinery. By S. P. Thompson, D.Sc, F.R.S. 



Fifth Edition. London : E. & F. N. Spon, 1896. 

 HPHE rapid increase in the number of technical applications of 

 -*■ Electricity has occasioned the development of many new types 

 of machinery in recent years. Any treatise which aims at giving 

 a complete account of the principles involved in the construction 

 of these machines must therefore grow visibly larger with each 

 new edition. Prof. Thompson's work has reached the stage at 

 which a single volume will not contain all the new matter without 

 omitting or condensing part of the text of previous editions ; con- 

 sequently he has been obliged to transfer a portion of it to another 

 treatise (' The Electromagnet ') where it can be more adequately 

 discussed. Even with this overflow some curtailment of the 

 more theoretical chapters has been found necessary, and it seems 

 evident that the sixth edition, whenever it appears, will be in two 

 volumes. 



The new matter in the present edition relates mostly to alternate- 

 current machinery; rotary-field motors have a chapter to themselves ; 

 and the methods of synchronizing alternators to run as two 

 dynamos or as dynamo and motor are described in a separate 

 short section. The volume is enriched by many plates giving 

 details of the construction of typical machines : and the student 

 whose thirst for knowledge on any point cannot be satisfied by the 

 text of the volume may often derive help from the plates, and 

 will find throughout the book copious references to other works. 



J. L. H. 



Elementary Treatise on Electricity and Magnetism, founded on 

 Joubert's ' Traite Elementaire d'Electricite.' By Gr. C. Foster, 

 F.R.S., and E.Atkinson, Ph.D. London: Longmans, 1896. 



Tiiat the French physicists excel in the writing of elementary 

 text-books is evidenced by the great popularity of the treatises by 

 Granot and Deschanel, the translations of which have passed 

 through very many editions in this country. Although not nearly 

 so well known in England, M. Joubert's Traite elementaire d'Elec- 

 tricite has a deservedly high reputation in France : its scope is 

 somewhat wider than that of the other two works, but the subject 

 is treated logically and in a progressive manner throughout. In 

 common with many other text-books, both English and continental, 

 it has, however, the disadvantage of presenting too exclusively the 

 action-at-a-distance character of electric and magnetic attractions, 

 and it does not sufficiently emphasize the importance of the medium 

 which, according to more modern ideas, is the seat of electric force 

 and energy. Undoubtedly, the older view furnishes a beginner 

 with an easy explanation of the simpler phenomena of electrostatics 

 and magnetism, and, once adopted, it can only be discarded with 

 difficulty. Prof. Carey Foster and Dr. Atkinson, taking M. 

 Joubert's work as a basis, have found much re-writing necessary 

 in their endeavour to present such explanations of all phenomena 



