198 



NATURE 



[December 15, 1910 



connection with the strict minimum, and various other 

 topics. Finally, there is a note on implicit functions. 

 Various interesting special theorems occur, by the 

 way; as an instance, we have the theorem that if y 

 vanishes for x — a and x — h, the integral 



/lii-'-HS)'-"-^"-' 



is never negative. 



It will be seen that this treatise is more for the 

 advanced student than for the beginner ; in fact, as 

 the author expressly takes the theory of the differ- 

 ential and integral calculus for granted, the reader 

 should be prepared with a good knowledge of analysis, 

 including function-theory. In any case, the subject is 

 intrinsically difficult, owing to the vagueness of the 

 data when the problem is put in its general form ; 

 it is rather a matter of surprise that so much has been 

 done, without unduly restricting the nature of the 

 functions involved. 



In conclusion, it should be stated that the treatise 

 is based upon a course of lectures at the College de 

 France, and that the redaction has been carried out 

 by M. Frechet, to whom M. Hadamard makes his 

 acknowledgments G. B. M. 



HYDROELECTRIC ENGINEERING. 

 Hydroelectric Developments and Engineering. A 

 Practical and Theoretical Treatise on the Develop- 

 ment, Design, Construction, Equipment, and Opera- 

 tion of Hydroelectric Transmission Plants. By F. 

 Koester. Pp. xxv + 454. (New York: D. van Nos- 

 trand Company; London: A. Constable and Co., 

 Ltd., 1909.) Price 215. net. 



HYDROELECTRIC power plants do not call for 

 the same attention in this country as in America 

 and on the European continent. Yet what English 

 engineer who has visited such installations has not a 

 store of vivid recollections and happy experiences? 

 The mountains and the forests, the streams and the 

 waterfalls — for the generating stations of hydro- 

 electric plants are usually away out among the beau- 

 ties of nature— all bring back memories of pleasant 

 tours and the like, whilst so far from destroying the 

 attractiveness of their surroundings by harnessing 

 nature's forces in this way, the author of the present 

 work maintains that the scenery has at times been 

 made more interesting, when proper attention has 

 been paid to the architecture and situation of the 

 buildings. This opinion is well upheld by many of 

 the splendid photographs reproduced so well in this 

 large volume. 



The title of the book, however, is certainlv ambi- 

 tious, and, criticised from this point of view, we fear 

 that the treatment on the whole is too general and 

 descriptive, even to the point at times of being 

 meagre, to be of great service to those directly con- 

 nected with hydro-power plant installations. This 

 will be further understood from the table of contents, 

 which comprises chapters on dams, headrace, pen- 

 stocks, power plant, mechanical equipment, electrical 

 equipment, electrical transmission, substations, line 

 protection, and a long list of developments, any one 

 NO. 2146, VOL. 85] 



of which could occupy such a volume by itself. Hence 

 it is almost inevitable that only a bird's-eye view 

 could be given when all these subjects were brought 

 within the compass of one book. It may be recalled 

 that this popular mode of treatment appears to meet 

 with more favour in America than in countries this 

 side of the Atlantic. With this one reservation, how- 

 ever, we have nothing but praise for the general 

 excellence of the book, the care devoted to its arrange- 

 ment, and the high quality of its illustrations. 



To show that the writer is well up-to-date, it is 

 only necessary to refer to a few of the new features 

 in hydroelectric developments which are dealt with in 

 their respective chapters : — Airshafts and equalising 

 chambers in connection with pressure tunnels ; seam- 

 less welded, flangeless, telescoping penstocks to facili- 

 tate shipment and to eliminate expansion joints ; 

 siphon system, in contradistinction to the inverted 

 siphon ; impulse wheels with draft tubes and multiple, 

 non-water-wasting nozzles ; compound turbine on a 

 single shaft, the discharge of one being the supply of 

 the other ; rapid and complete turbine tests by certain 

 methods and autographic recording device ; 30,000-volt 

 generators and their efficient protective devices against 

 lightning. Unique combination of single and three- 

 phase high-tension transmission systems from three- 

 phase generators; wagon-panel switchboard systems; 

 segregation and decentralisation of switchboards ; con- 

 tinuous water-flow grounders and horngaps with 

 micrometric setting. Two-legged transmission towers 

 and line-crossing protection. 



At the end of each chapter is appended a biblio- 

 graphy of works and papers to which the student may 

 turn for further information ; this compilation is by 

 no means the least valuable feature of the book. 



Occasionally the author's treatment includes matter 

 where his judgment seems to have been less sound. 

 Thus in discussing electric generators, he states there 

 are three types — the inductor, the revolving armature, 

 and the revolving field. But surely there is no reason 

 for treating all these at equal length ? — indeed, little 

 harm would have been done if the discussion of the 

 first two types had been omitted completely in describ- 

 ing modern high-tension machines, unless, of course, 

 the author intended to enter into the province of the 

 designer in order to bring out certain advantages in 

 the older types which have recently become prominent. 

 Nor is sufficient attention paid to the development of 

 high-speed water-turbine sets of large output. It 

 would have been well to have supplied a table giving 

 outputs and speeds of modern turbine sets for the 

 various classes of turbines. 



Here and there an error has been allowed to remain 

 in the text, whilst at times important questions, such 

 as the effect of capacity in transmission lines, have 

 been omitted. 



Following a ver}' useful and well-written chapter on 

 line protection (lightning arresters), the last section 

 of the book is devoted to a detailed description of 

 eight modern American and European hydroelectric 

 developments, which serve well to show the immense 

 advance made in water-power installations during 

 recent years. 



Stanley P. S.\iith. 



