586 



NA TV RE 



[October 19, 1893 



believing might ultimately prove to be indigenous. Among 

 the latter were many moths which were really omitted 

 from, instead of inserted in, the British list "without 

 authority," by the late Henry Doubleday, and which have 

 since been proved to be indigenous, and reinstated. But 

 we are glad to find that Mr. Barrett admits Lyccena 

 argiades and Danais Archippus among our native butter- 

 flies. The latter, though an importation from America, 

 has been so frequently taken in England of late years, 

 that it is hoped it may become permanently natural- 

 ised. On the other hand, there are several apparently 

 extinct species, formerly common in England, such as 

 Chrysophanus dispar, last taken in 1865, as well as others 

 which appear to be now on the verge of extinction as 

 British species, without any obvious reason, such as 

 Aperia cratcegi and Polyoinmatiis ads. In a few years 

 we fear that entomologists may have seriously to con- 

 sider the desirability of finally erasing several of our 

 British butterflies from our list as absolutely and un- 

 doubtedly extinct. Per contra, we may look for oc- 

 casional additions (though very rarely among the butter- 

 flies) among species which are possibly overlooked or 

 confounded with others, like Lyccena argiades and 

 Hesperia lineola, the two latest novelties. In the case of 

 Lycana batica, fir%t taken in England in 1859, there is 

 good reason to believe that the species is naturally ex- 

 tending its range in North-Western Europe. Possibly 

 this may also be the case with the moth, Syntomis phegea, 

 which is said to have been taken once or twice in 

 England of recent years, and which, though gregarious 

 and generally abundant wherever it is found, is excessively 

 local north of the Alps, though there are several isolated 

 colonies in Germany and the Netherlands. 



We could have wished that Mr. Barrett had paid more 

 attention both to the foreign literature relating to British 

 butterflies, and to the older English literature before 

 Haworth ; but no man can accomplish everything, and 

 within the limits to which he has confined himself his 

 work must be regarded as by far the best and most com- 

 plete which has yet appeared. W. F. Kirbv. 



COOKE ON LOCOMOTIVES. 



British Locomotives. By C. J. Bowen Cooke. (London 

 and New York : Whittaker and Co., 1 893.) 



LOCOMOTIVE engineers, like their brethren in the 

 medical profession, very often differ widely in their 

 practice ; again, they often follow the practice of some 

 older locomotive engineer dead and gone, may be. Who 

 can say that the late Mr. William Stroudley has not left 

 liis mark on the locomotive design in this country, and 

 that many British railways do not bear his handiwork 

 in the design of their locomotive stock ? To the layman 

 the question why certain railways have engines with 

 domes, and other railways have engines without domes, 

 will always remain unanswered. The same may be said 

 of bogies, injectors, pumps, &c. 



In the large locomotive works, where engines are built 



by contract, these divergencies of practice are brought 



prominently forward, and one is in danger of coming to 



the conclusion that anything will do in the way of loco- 



NO. T251. VOL. 48! 



motive design. Nor is it only in the design that there is 

 so much variation, for one finds quite as much in the sys- 

 tems of doing work often rigidly specified to be followed. 



Another point also deserves attention. .Since the use of 

 steel has come into use as a material for the construction 

 of boiler shells, it is amusing to observe the different ways 

 this material is handled, or rather specified to be handled. 

 Some engineers allow the plates to be sheared to size, and 

 the rivet holes punched full size without hesitation ; others 

 again partly follow this practice, but require the sheared 

 edges of plates to be planed to a depth of a quarter of an 

 inch, and punched holes to be machined to a depth of an 

 eighth of an inch on the diameter. Another scRool de- 

 clines to have punched rivet holes at any price. The 

 same variation in practice holds good with the question 

 of annealing the plates, and particularly the flanged plates 

 which go to form the boiler. 



It is possible to take the principal parts of a locomo- 

 tive and to demonstrate that what is considered good 

 practice by one locomotive engineer is considered by 

 some other to be decidedly wrong, and for this reason 

 no good can be attained by following this view iif the 

 question further. Any book, therefore, treating on loco- 

 motive engineering will naturally tend to follow the prac- 

 tice of some particular locomotive engin eer as regards 

 design, and particularly the details, the principles of 

 course being the same in all cases. 



The volume before us " does not profess to be a 

 scientific work ; its purpose being more to give the reader, 

 who may not feel disposed to dive into figures and cal- 

 culations, some information about locomotives in a con- 

 densed and intelligible form." This is to be regretted, 

 because there is no modern work on locomotive design 

 available for reference.' But on the other hand, the author 

 has written a most readable book, useful alike to the 

 apprentice and lay reader. 



The author, being on the locomotive staff of the 

 London and North-Western Railway, naturally follows 

 the practice in vogue on that line, and a better example 

 of good all-round locomotive engineering will be difficult 

 to find. 



The volume may be roughly divided into three parts ; 

 viz. the early history of the locomotive, details of con- 

 struction of recent engines, and descriptions of modem 

 locomotives in use on the principal railways in this 

 country. In all three divisions the author has done ample 

 justice to the subject ; although, as we have before pointed 

 out, the book would have been of far more value to an 

 engineer had the author gone deeper into the question Q 

 design, and particularly the strengths of parts. 



Chapter v. deals with the boiler, the most important 

 and delicate part of a locomotive engine ; for given a well- 

 made boiler of ample capacity, then the engine will have 

 every chance of being a success. The author on page 

 91 mentions Bessemer steel as a material for boiler shells 

 n such a way as to give an impression that it is the com- 

 mon practice to use that material for this purpose, 

 whereas Siemens-Martin open hearth steel is generally 

 used, and Bessemer steel is the exception. Further on. 

 the tensile strength of various materials used for making 

 boiler shells is given. Surely the author should also 

 specify an extension or contraction of area as well ? 



