422 



NATURE 



[December i6, 1915 



of his book on the steam engine had accepted the 

 characteristic equation of Callendar and had 

 utilised the steam tables derived from it by 

 Mollier, and had thus directed the attention of 

 the British engineering world to Callendar's re- 

 searches, it is to be feared that the majority of 

 our engineers were still ignorant of and oblivious 

 to the epoch-making character of Prof. Cal- 

 lendar's researches and his work in the field of 

 thermodynamics. 



Prof. Dalby has made it impossible for anyone in 

 the future to ignore these researches. In chapter 

 iii., on the motive-power circuit-thermodynamics, 

 in sections 47 to 49 Callendar's characteristic 

 equation of steam is dealt with in a clear and 

 concise fashion ; and the whole of the steam 

 tables in the appendix have been calculated by 

 Prof. Callendar himself from the expressions given 

 in this chapter. In chapter iv. the sections deal- 

 ing with the so-called " missing quantity " are 

 practically based upon the researches of Callendar 

 and Nicolson (by a slip in the preface an account 

 of these researches is stated to be incorporated in 

 chapter v.), and lastly Prof. Callendar's work on 

 the theory of the flow of steam through nozzles 

 is made free use of in chapter xi., which deals 

 with this important branch of the subject, of such 

 vital importance in the design of steam turbines. 

 We have indicated enough to show how largely 

 the author has drawn upon the rich stores of 

 theory and experimental results which Prof. Cal- 

 lendar has placed in recent years at the disposal 

 of engineers. 



Following Sir J. A. Ewing, the author has 

 abandoned the Fahrenheit and adopted the Centi- 

 grade scale; modern research is always ex- 

 pressed in terms of this latter scale, and it is 

 certainly high time that British and American en- 

 gineers discarded for ever the Fahrenheit scale, 

 which introduces needless complications, and has 

 nothing to commend it ; for commercial reasons 

 alone it would be a great advantage to engine- 

 builders and others to come into line with the 

 rest of the world and to adopt the Centigrade 

 scale. It may be a difficult matter to introduce 

 in its entirety the metric system, though we have 

 little doubt that sooner or later such a change 

 must be made, but it would surely be an easy 

 matter to pass an Act enforcing the use, after a 

 given interval of time, of the Centigrade thermo- 

 meter and making it illegal to manufacture any 

 longer Fahrenheit thermometers. The Meteoro- 

 logical Department has recently made a valuable 

 step forward in deciding that in future rainfall 

 records shall be given in millimetres. Why not 

 go a step further and publish all their temperature 

 records in the Centigrade scale? Were the De- 

 NO. 2407, VOL. 96] 



partment to take this step the public would soon 

 fall into line, and in a short time everyone would 

 as readily think in Centigrade units as they do 

 now in Fahrenheit units. We warmly congratu- 

 late the author for the decision he came to in this 

 matter ; for the time being it is necessary, if we 

 use the Centigrade scale, to adopt a somewhat 

 unusual heat unit — the lb. -calorie, but such a unit 

 is inevitable so long as we retain the pound as 

 the unit of weight. 



Prof. Dalby has for some time been in the front 

 rank of those workers who have specialised in 

 that section of thermodynamics which deals with 

 the problem of the steam locomotive, and he has 

 drawn freely upon his published researches for 

 much of the matter contained in chapter viii., 

 which deals with the motion of a train and the 

 rate at which energy must be spent to produce, 

 to maintain, and to destroy it. This chapter will 

 prove invaluable to the designers of locomotives ; 

 it is largely the result of original work, and the 

 problems to be solved have been attacked in a 

 strikingly novel manner. The validity of the 

 author's methods has been confirmed by 

 examination of the published results of elaborate 

 tests of the performances of locomotives carried 

 out in the United States. It is well known that 

 Prof. Dalby has organised a highly successful 

 post-graduate course in railway engineering at 

 the Imperial College of Science, South Ken- 

 sington, and this chapter is a striking testi- 

 mony to the thoroughness with which he is at- 

 tacking the problems which will have to be faced 

 if any radical improvement in the thermal effici- 

 ency of the steam locomotive is to be obtained 

 in the near future. 



Two other chapters which will be specially 

 useful to the drawing office are those dealing 

 with the balancing of engines, and valves and 

 valve-gear diagrams, treated, of course,' in a more 

 condensed fashion than in the author's well-known 

 text-books on these two branches of engine 

 design, but still in a sufficiently full and complete, 

 form for the engineer who aims at acquiring a 

 sound knowledge of the principles upon which the 

 successful design of engines must be based. 



The last chapter deals with steam turbines, and 

 we think Prof. Dalby has in this chapter pro- 

 duced the best account we have ever read of this 

 class of steam generators, both from the point 

 of 'theory and of actual design, and it says much 

 for his methods that he has been able to do this 

 in some seventy-five pages. 



If we have any criticism to offer on this book, 

 it is in the form of a suggestion that in any re- 

 issue the book should be broken up into two 

 volumes. The present volume contains 760 pp., 



