NA TURE 



[December 23, 1922 



the heat treatment of steel. Many other tool makers 

 have been in the same position. It has, however, been 

 left tn Mr. Urquhart, not merely to make a study of 

 the processes involved, but to write a book on them 

 from a practical engineering view-point. In doing 

 this he has rendered a service to his brother engineers 

 which they will probably not be long in recognising, 

 for he has written his book in language which is as free 

 from technicalities as possible. 



The time has gone by when steels as received from 

 the makers were forthwith worked into machines, 

 without any preliminary treatment, and when it was 

 not realised that a thermal process could add enor- 

 mously to their physical strength and effectiveness. 

 In consequence there has been a revolution in the 

 engine and machine building trades within the last 

 few years, which is only realised by the men engaged 

 in those trades. As the author points out, not only 

 have great improvements been introduced in the 

 treatment of well-established carbon steels, but they 

 have been followed by a remarkable development in 

 the use and heat treatment of alloy steels. These 

 advances have necessitated the application of better 

 systems of applying heat and measuring the tem- 

 peratures produced, and these in their turn have led 

 to the introduction and development of electrical 

 methods of heating, which are capable of a higher 

 degree of control and accuracy. 



The early chapters of the book deal with the recent 

 developments in metallography as applied to steels. 

 The author has mastered the theory of the iron-carbon 

 equilibrium, as applied to both carbon and alloy steels, 

 and this is one of the best parts of the whole book. As 

 he points out, one of the most remarkable effects of 

 alloying nickel with mild steel is the lowering of the 

 temperature of the Aci range, an effect which means 

 diminished cost of working the steel, a greater margin 

 of safety against over-heating, increased ductility, 

 toughness, and resilience in the finished product. The 

 physical characteristics of steels and testing methods 

 are next described, and these are followed by an out- 

 line of thermal processes. Chapters on furnaces and 

 their methods of working come next, and a very good 

 account is given of pyrometers and their application 

 to the thermal treatment of steels. Methods of case- 

 hardening, both by solid and gaseous reagents, are next 

 described, and these are followed by details of the 

 various methods of quenching. Later chapters deal 

 with various types of tools and typical heat treatments, 

 and in the last two chapters accounts are given ol 

 the thermal treatment of high-speed tool steels and 

 stainless steels. 



To some extent the book is an attempt to co-ordinate 

 the work of the laboratory with that of the engineer's 

 NO. 2773, VOL. I IO] 



hardening department ; and with this end in view, the 

 author has included a series of photomicrographs 

 illustrating the structures of steels at various stages 

 of heat treatment under workshop conditions. He has 

 availed himself of the experience of well-known metal- 

 lurgistSj such as M. Guillet and the late Prof. Howe on 

 the academic side, and of Sir Robert Hadfield, Mr. S. 

 Brayshaw, and Prof. Giolitti on the practical side. 

 There is no doubt that the volume will be widely 

 welcomed by practical men, and it should do much to 

 raise the standard of the scientific heat treatment of 

 tools and machine parts. H. C. H. C. 



Mosquito Control. 



Mosquito Eradication. By W. E. Hardenburg. Pp. 

 ix + 248. (New York and London: McGraw-Hill 

 Book Co., Inc., 1922.) 15s. 



IX this small book the author gives a clear and 

 concise account of the measures which have been 

 found successful in controlling mosquitoes in America. 

 The brilliant results of the anti-mosquito work in 

 Havana and the Isthmus of Panama have been fully 

 appreciated in the United States. Dr. G. A. Le Prince, 

 formerly Chief Sanitary Inspector, Isthmian Canal 

 Commission, wrote, in the Annual Report, U.S. Public 

 Health Service for r92o, "The public view-point has 

 changed ; villages, towns, county and state officials, 

 as well as business corporations and railroads, now 

 realise the extent of the large preventable financial loss 

 the] incur each year. . . . The people have been watch- 

 ing the campaigns undertaken, and throughout the 

 country they are becoming more and more interested 

 in having their own community and state undertake 

 this work. . . . This calendar year, 101 places are 

 (loin- work under the supervision of the Public Health 

 Service, and have already appropriated $280,000 

 therefor." 



The modern methods of mosquito control are merely 

 elaborations of those originated by Sir Ronald Ross in 

 the East and by General Gorgas in the Canal zone and 

 Cuba ; they have already been described very graphic- 

 allv by Le Prince and Orenstein. But Mr. Hardenburg, 

 who is a sanitary engineer, has treated the subject from 

 a somewhat different point of view from that adopted 

 in " Mosquito Control in Panama." Descriptions are 

 given of the more important American culicine and 

 anopheline mosquitoes. These, though brief, are 

 sufficient to enable a sanitary officer to recognise most 

 of these insects that he is likely to meet with ; the 

 information given in the body of the book is sup- 

 plemented, in an appendix, by a more technical key for 

 the identification of both larvas and adults. 



