io8 



NA TURE 



[July 22, 1922 



often laboriously, by even living predecessors. There 

 are too many clear instances of this in his book. 



Despite its drawbacks, however, the book supplies 

 much good evidence on its subject, and the student will 

 do well to make its acquaintance. With the second 

 part one is not inclined to quarrel. It propounds a 

 theory which cannot be gone into in a short review ; 

 but whether a theory stands criticism or not as time 

 goes on, it is a good thing to put it forward, as the mere 

 dissection of it promotes research and the acquisition 

 of knowledge resulting from the research. 



R. C. T. 



Hydro-Electric Engineering. 



Hydro-Electric Engineering. Vol. I, Civil and Mechani- 

 cal. Editor : Dr. A. H. Gibson. Contributors : 

 H. D. Cook and the Editor. Pp. x + 232. (London : 

 Blackie and Son, Ltd., 1921.) 255. net. 



THE water resources of the world, from the point of 

 view of available power for domestic, industrial, 

 and agricultural uses, have received very considerable 

 attention in recent years, and in many countries a large 

 amount of information has been accumulated as to the 

 amount of water-power that is available for exploita- 

 tion. Not only have various sources of power, such 

 as those of the great waterfalls, been harnessed, but 

 in addition many schemes for impounding waters in 

 suitable valleys and utilising them for power generation, 

 irrigation, and for distribution to cities many miles 

 distant have been carried into effect and at the present 

 time many more are receiving serious consideration. 

 In this country much has been done to impound waters 

 for town and city purposes, but comparatively little 

 has been attempted to develop the water-power 

 available. Until the war came, with all its consequent 

 economic problems, not least of which is the very 

 serious increase in the price of coal, power could be 

 produced by steam-engines and internal combustion 

 engines at a price which made it practically impossible 

 for water-power to compete, involving as it does large 

 capital outlays per unit power produced and cost of 

 transit over long distances. It is perhaps not sur- 

 prising, therefore, that although Fairbairn and James 

 Thompson in the British Isles were largely responsible 

 for the very important developments which took place 

 in water wheels and turbines in the nineteenth century, 

 and the correct principles of design were very largely 

 developed here and in France, yet neither of these 

 countries have developed water-power as have, for 

 example, Switzerland, Norway, and the United States. 

 Students in Great Britain have not been encouraged 

 to take a very keen interest in the subject and the 

 NO. 2751, VOL. T IO] 



literature published in this country has been somewhat 

 scanty. 



Recently, however, the Water Resources Committee, 

 which has issued a number of reports, has investigated 

 the power available in Great Britain, and a good deal 

 of interest has been aroused in the possibilities of the 

 development of hydro-electric power schemes. An 

 equal interest has been awakened in other parts of the 

 empire where the power available is much greater than 

 here and where coal is not so easily obtained. This 

 work on hydro-electric engineering comes, therefore, 

 at an opportune time, for it is desirable that engineers 

 and business men should understand clearly the 

 principles underlying the storage and use of water for 

 power purposes, and engineering students should have 

 available a trustworthy guide in the study of the 

 subject. A word of warning is required to those who 

 hope to take a short cut to knowledge of the subject. 

 In few branches of engineering have such diverse 

 matters to be dealt with, and thus only those who are 

 prepared by a sound training in engineering principles, 

 civil, mechanical, and electrical, can appreciate fully 

 and overcome the difficulties. 



In the work before us, the authors have discussed 

 some of the important principles involved but a great 

 part of the work is occupied with descriptions and 

 details of actual works. The all-important subject 

 of the relationship of the water available to the rainfall 

 on a given watershed, the power that can be obtained, 

 and the problem of the flow of water and its measure- 

 ment receive adequate treatment in the first third of 

 the book. 



The remaining portion of the book deals entirely 

 with turbines. The various types are described with 

 the aid of drawings of actual turbines, and the principles 

 of design are discussed. It is of the greatest import- 

 ance that the behaviour of turbines under variable 

 conditions of gate opening and speed should be known, 

 and typical characteristic curves are given for reaction 

 turbines in which unit power is plotted against unit 

 speed for various gate openings. Efficiency curves 

 are also shown for turbines working under varying 

 conditions of load. The Pelton Wheel is described 

 and the theory discussed. The all-important question 

 of the choice of the most suitable type of turbine for 

 particular conditions is somewhat briefly referred to 

 but the essential points to be considered are clearly 

 presented. 



An important chapter is devoted to speed regulation, 

 and hydraulic problems connected with any attempt 

 to change suddenly the flow of a large volume of water, 

 and the theory of the surge tank are clearly discussed. 

 Johnson's approximate formula for the movement of 

 the water in a large tank for a given change of velocity 



