April 20, 1916] 



NATURE 



^59 



more to the student of heat engines and the pro- 

 spective user of this particular type of prime 

 mover. 



(i) The keynote to the first volume is undoubt- 

 edly the explanation of the actual designing of the 

 marine Diesel engine and its component parts, and 

 it seems quite wonderful that modern practice has 

 so rapidly become to a large extent standardised. 

 The translation from the original has evidently 

 been undertaken by engineers skilled in the prac- 

 tice of their profession and in sympathy with the 

 subject-matter of the text. The original treatise 

 is the work of an Italian specialist in the de- 

 \elopment of the Diesel motor, Giorgio Supino, 

 whose early decease is a real loss to Italian en- 

 gineering. Naturally the reader will ask what 

 las this eminent foreign author to say about 

 iBritish-made Diesel engines and British manufac- 

 liurers; at the end of part i., page ^^2, is a table 

 ■jiving a list of ships and the types of engine 

 Adopted, viz., high speed, low speed, 4 cycle, and 

 {: cycle, and it is noticeable that one only out of 

 |;ome twenty names is that of a British firm. 



This surely is a matter which vitally concerns a 

 Inanufacturing country such as ours. Recollec- 

 tions of the early years of the petrol motor and 

 inotor-car industry and a comparison with the 

 tate of our present manufactures makes one 

 levoutly hope that histor}- will repeat itself and 

 hat full advantage will be taken of the experience 

 nd experimental labours of our Continental com- 

 etitors, so that the supoly for our colonies may 

 ,ome from this countr^^ No discussion on the 

 lerits of Diesel engines can be entered upon with- 

 ,ut reference to that class known as semi-Diesel, 

 jhich latter are perhaps better termed hot-bulb 

 Kgines. It is good to think that our output of 

 jiese is more satisfactory, but the magnitude of 

 »e units employed of this class is small compared 

 ith that of engines of the Diesel type. It is 

 so good to remember that the engine called semi- 

 iesel is in reality the direct outcome of the work 

 an English engineer, Mr. Stuart Akroyd, whose 

 •me is associated with the firm of Messrs. 

 ornsby and Sons, Ltd., in the production of the 

 .ornsby- Akroyd engine, and it would therefore 

 jem a better name for this type of engine that 

 ' should be termed "engines working on the 



'vd cycle," rather than "semi-Diesel." 

 A brief review of the first book shows that 

 rt i. deals with a general survey of the types of 

 engines in general use, with a discussion on 

 iiciencies. Chapter vi. gives methods of calcu- | 

 Ijmg cylinder dimensions; this is succeeded by | 

 papters dealing with the designs of various parts, I 

 sj:h as bed-plates, crank cases, engine framing, 

 '^ nk-shafts, pistons, cylinder heads, valves, fuel 

 tion and regulation, etc., all verv clearly 

 t rated by excellent drawings and plates. 

 >1thods of reversing marine engines give up-to- 

 e practice, and it is startling to realise that the 

 ole cycle of reversing can be performed in 

 f^r^"f"?f' "^ ^"''^^ chapter deals with trials and 

 y^s of Diesel engines. It would be a help if a 

 ulated form of "report on a trial" were in- 

 NO. 2425, VOL. 97] 



eluded, as standardisation is very desirable in any 

 form of comparative tests. From this short review 

 it would appear that the subject-matter is really 

 the complete design of Diesel engines for marine 

 purposes, and as such it is a meritorious addition 

 to engineering literature. 



(2) The second volume is a greatly enlarged and 

 much rewritten edition of a work which first 

 appeared in the spring of 1912, almost contem- 

 poraneous with the last public appearance of Dr. 

 Diesel in London. The defects of the first edition 

 (which bore traces of hurried preparation) have 

 disappeared, and we now have a copiously illus- 

 trated and enthusiastic survey of the progress of 

 the Diesel engine, with many examples of modern 

 types for land and marine installations, and an 

 optimistic claim for its future development as the 

 prime mover for mechanical transport. In this 

 volume are upwards of forty-five folded plates, 

 which give the main dimensions and cross-sec- 

 tions of the chief types of engines constructed. It 

 is satisfactory to note that British types figure 

 more prominently in this book. One of these, 

 viz., the Tanner-Diesel, is shown on page 264. 

 The writer remembers the early struggles of Mr. 

 Tanner to get his designs taken up, and is glad 

 to pen this tribute to his faith and earnest- 

 ness in carrying through his designs to a 

 successful issue in the face of great difficulties. 

 It will be noticed that the progress made in the 

 last four years has been mainly in the develop- 

 ment of the two-stroke cycle type, and the increase 

 of h.p. developed per unit employed. A perusal 

 of the table on page 317 shows that the maximum 

 diameter of cylinder is now 30 inches, and that 

 the maximum h.p. per cylinder is 650 for a 2-cycle 

 engine, but the average h.p. per cylinder is only 

 230 for this class, and for the 4-cycle slow-speed 

 type the average is only 125 h.p.' per cylinder, a 

 figure which represents the performance of the 

 Selandia, the boat Londoners had a chance to 

 inspect whilst she was lying in the Thames in 

 191 2. The figures given justify the claim of the 

 author of this book that the 2-stroke cycle is that 

 of the future. To the student and others who 

 desire to understand this engine and its working 

 this volume will be of great service. 



It would be interesting to refer to the develop- 

 ment of the Diesel engine and its use to extend 

 submarine warfare, but the present is not oppor- 

 tune for any remarks on this point. A. J. M. 



OUR BOOKSHELF. 



Instincts of the Herd in Peace and War. By W. 

 Trotter. Pp. 213. (London: T. Fisher Unwin, 

 Ltd., 1916.) Price 35. 6d. net. 



An interesting and useful sociological survey. 

 The author contends that the subject can really 

 become a science, practically useful by conferring 

 foresight. It is not necessarily only a mass of 

 dreary and indefinite generalities, but may become 

 a guide to the actual affairs of life, giving an 

 understanding of the human mind which may en- 



