January 28, 1909] 



NA TURE 



365 



clearly set forth, and illustrated by numerous experi- 

 ments and well-drawn diagrams. Its weak point, if it 

 has a weak point, is that it is a little too didactic and 

 not sulliciently suggestive. There is little to stimulate 

 the student to ask himself or other people questions 

 relating to what he has read, which may be partly 

 due to the rather crowded mass of information. To 

 take one example, the action of steam on various 

 metals is described ; some react and others do not. 

 No comment is made or question raised as to the 

 reason of this remarkable difference, and the student 

 must be satisfied with the bare fact. J. B. C. 



OUR BOOK SHELF. 

 The Theorv and Practice of Bridge Construction in 



Timber, Iron and Steel. By Morgan W. Davies. 



Pp. viii-l-594. (London : Macmillan and Co., Ltd., 



igoS.) Price 12s. net. 

 This work is based upon notes of lectures delivered 

 bv the late Mr. Davies to students of civil engineer- 

 ing at the Swansea Technical College, and the 

 aim the author had in view was to collect together 

 a series of easily understood rules to enable problems 

 of bridge design to be solved by graphical and 

 analytical methods. The first two chapters arc de- 

 voted to the routine problems connected with the 

 bending moments and shearing forces of simple and 

 built-in beams ; then follow a series of chapters on 

 stresses in the bars of framed structures; all the 

 trusses which have been generally used in bridge 

 construction are considered ; in some cases graphical 

 methods are employed, and in others, such as lattice 

 girders and bow-string girders, analytical methods. 



Special chapters are devoted to such subjects as 

 I he moment of resistance of beams, the strength and 

 fatigue of iron and steel, the strength of columns, 

 and the design of riveted joints. The various rules 

 which have been proposed for fixing the working 

 stresses in the different members of bridges are 

 given, and their justification discussed; the recent 

 failure of two long-span bridges in America empha- 

 sises the importance of this subject, and bridge 

 engineers will be hardly likely in future to be any 

 more enamoured of the rules laid down by certain 

 well-known .American bridge designers for the work- 

 ing stresses in struts than they have been in the past. 

 The design of arches is very fully dealt with in 

 chapter xiii. ; both masonry and metallic arches are 

 treated of, though, as is usual in text-books, much 

 more space is devoted to the latter; this chapter will 

 h" one much consulted by the student, who generally 

 finds more difficulty in determining the stresses in 

 metallic arches, and in selecting suitable forms for 

 the different members, than he does when dealing 

 with ordinary trusses; the methods adopted by the 

 author are clear and concise. 



This chapter is followed by three which treat of 

 suspension bridges, opening or draw bridges, and 

 traversing or transporter bridges, and then by a 

 rtiaptor full of useful practical details on various 

 tvpcs of bridge flooring, piers, and bolsters, or shoes, 

 for distributing the pressure uniformly to the bear- 

 ing plates. In the last chapter the author has 

 worked out several complete examples of bridge de- 

 sign in order to illustrate the principles he has laid 

 down in the earlier chapters; these examples include 

 timber trestle bridges, highway bridges with steel 

 main girders, a nlate girder railway bridge, and, 

 lastly, a Murphy Whipple truss railway bridge of Ton- 

 feet span. These examples will be of considerable 

 service to the voung designer and to the student. 



T. H. B. 



NO. 2048, VOL. 79] 



Metallic Allovs : their Structure and Constitution. 

 Bv G. H'. Gulliver. Pp. xv+254; illustrated. 

 (London : C. Griflin and Co., Ltd., 190S.) Price 

 6s. net. 

 The study of metallic alloys is a " practical " subject. 

 Many alloys were discovered long ago by accident, 

 and the development of their manufacture and use 

 is based on empiricism. Even the recent introduction 

 of a number of other alloys has owed little to theo- 

 retical considerations, and no attention is paid to 

 predictions as to the properties of untried combina- 

 tions. There is plenty of experimental evidence to 

 be classified and discussed, but the time has hardly 

 come for the logical method of treating the subject 

 adopted by Mr. Gulliver. At any rate, the book 

 would have been better balanced if more attention 

 had been paid to the experimental data. 



The author has adopted the classification of alloys 

 presented by Roberts-Austen and Stansfield at the 

 Congres international de Physique in 1900. This 

 classification was based on Roozeboom's study of equi- 

 librium in mixtures, but the author has amplified it 

 in many respects, and with its aid has been enabled 

 to present a tolerably complete theory of alloys on a 

 svstematic basis. He has consistently applied the narne 

 "solution " to anv physical mixture of metals, liquid 

 or solid, and there' is doubtless no disadvantage in this 

 way of regarding them, though it has not much claim 

 to be considered as a " method of study." One of the 

 difficulties in applying the solution theory tp alloys 

 in practice is that equilibrium is not established in 

 solid mixtures in any reasonable length of time under 

 ordinary conditions. The alloys used in the indus- 

 tries are generally in an unstable state, and when 

 equilibrium has been established in them it often 

 happens that their usefulness has departed. This is, 

 of course, one of the reasons why the recent study 

 of alloys has not thrown more light on their useful 

 properties. 



The book, taken by itself, will not be of much 

 use to engineers or manufacturers. It is not even 

 quite what is wanted for students, but it may be 

 recommended to their teachers. The weakest part 

 of the book is that devoted to methods of investiga- 

 tion, which could have been made to afford much more 

 help to those engaged in research. Its greatest claim 

 to be read is that it gives a more complete classifica- 

 tion of alloys than has hitherto been available. 



(i) Ex-meridian, Altitude, .izittnith, and Star-finding 

 Tables. By Lieut.-Commander Armistead Rust, 

 U.S. Navy.' Pp. li + 393- (New York : John Wiley 

 and Sons; London: Chapman and Hall, Ltd., 

 1908.) Price 21s. net. 



(2) Nautical Charts. By G. R. Putman, Director of 

 Coast Survevs, Philippine Islands. Pp. viii+162. 

 (Same publishers, 190S.) Price 8s. 6d. net. 



(3) A Text-book of Theodolite Surveying and Level- 

 ling. By Prof. James Park. Pp. x-(-2i6. (Lon- 

 don: C. Griffin and Co., Ltd., 190S.) Price 6s. 

 net. 



(i) The author has gathered together a very useful 

 set of tables and diagrams for finding the latitude, 

 facilitating the plotting of lines of position, and giving 

 new and practical rnethods for identifying stars in 

 cloudv weather. The tables extend from lat. o°-6s° 

 and declination 0° 71' north and south. The book 

 is excellently printed and arranged ; full descriptions 

 of how to use the tables are given, together with 

 examples. It should prove most useful to the 

 mariner, as its scope covers practically all the 

 navigable portions of the globe. 



(2) This small volume, which deals with the 

 methods of the U.S. Surveying Service, gives_ a very 

 good general idea of how the work is carried out 



