REVIEWS 351 



who has to supervise the running of the Diesel engines will need to read certain 

 portions of Part II., but the remaining portions can be referred to as occasion 

 demands. 



It is, however, interesting to note that the author expects all his readers to 

 have been properly trained in the fundamental portions of an engineer's educa- 

 tion. Taking random examples, we are told in Part I. (p. 60) that "to examine 

 with accuracy the thermo-dynamic values of the various cycles, recourse must be 

 had to the entropy temperature diagrams. . . . The entropy of the gas is — 



■-/? 



c v . \og e pv k + const." 



while on p. 62, fig. 64 shows the graphic conversion of curve T=/(v) into curve 

 T=f{E).» 



Further, in Part II. in the chapter on "Valve Actuating Gears," fig. 222a 

 indicates a graphic method of drawing a polarsinoid cam where — 



*-(-■+£)-&«"•)• 



While " in fig. 223, the curve of valve movement is drawn with the abscissae 

 representing time and the ordinates the lifts, /i, of the valve. From this curve 



another representing — r. may be drawn, in which the ordinates represent the 



velocity v at any instant, and thirdly _ the curve of accelerations, a, may be 



obtained." 



In a volume where each and every portion of the engine itself has been very 

 thoroughly treated, both in the text and by illustrations, it may seem a little out of 

 place to ask for more. But we feel the value of the book would be greatly 

 enhanced by a chapter on accidents to Diesel engines. They do occur, and are 

 generally serious. For instance, investigations into the causes of explosions have 

 been published, but, in general, the reasons given have not inspired confidence 

 that they were the true reasons. Again, troubles with the air compressors are 

 fairly common, but we see no reference to this or to the very great care that is 

 necessary in the lubrication of that portion of the plant and in the selection of the 

 lubricating oil. 



The translators could easily add a few pages on these points in the next 

 edition. We have no hesitation in very strongly recommending this book as an 

 excellent contribution to the science and practice of this most important branch of 

 engineering. 



J. Wemyss Anderson. 



Diesel Engines for Land and Marine Work. By A. P. Chalkley, B.Sc (Lond.), 

 A.M.Inst.C.E., A.I.E.E. [Pp. xviii + 368, with 172 figures.] (London: 

 Constable & Co., Ltd., 191 5. Price 8^. 6d. net.) 



This is the fourth edition of this work, and indicates very clearly that the author 

 has a good knowledge of the possibilities of the majority of English " technically 

 trained " engineers. 



The opening chapter is on the " General Theory of Heat Engines, with special 

 reference to Diesel Engines." If this theory, as given, is sufficient for the author's 

 purpose, then surely an Appendix should be added in which the term " entropy " 



