REVIEWS 533 



There are, however, one or two practical points that require the attention of 

 the authors. In such a text-book it is wise, perhaps, to leave out the important if 

 somewhat long and very practical work on rivets, rivet holes, and riveted joints 

 in general. This should not, however, mislead the authors into such examples as 

 given on pp. 280 and 281. Such a construction as shown in fig. 26, p. 280, is not 

 possible in practice, as the rivets must be " staggered " (on the scale shown) to get 

 them into position. 



Further, in example No. 2, p. 281, it is given : " If the rivets in fig. 26 be 

 pitched 4 in. apart, find the diameter necessary for each rivet." The problem is 

 worked out, and the answer given as 1*2 in. 



Such an example gives the student wrong ideas altogether, as the size of 

 rivet is a most important item in constructional work, and is determined by (with 

 other considerations) the appliances possible for closing them. A ijin. diameter 

 rivet may not be out of place on a Quebec bridge, but it certainly would not be 

 used in an ordinary plate-web girder from which the example is taken. A f in. or 

 f in. rivet would be used, and the pitch made to suit the rivet. 



We further certainly think more attention should be given to secondary stresses 

 and strains in structures, and, while admitting the very great value of the theory 

 and practice of the steel-arched girder, it is hardly wise to quote, without some 

 word of warning, examples fro/.-, station-roofs, which the tendency of modern 

 design clearly indicates as being quite out of date, as the huge span is now 

 replaced by a series of small spans. 



A number of small corrections is necessary throughout the book to bring it 

 into line with the practice adopted in printing the proceedings of our learned 

 societies. For instance, in Example 18, p. 15, we read : "A rod of steel, 10 ft. 

 long and "5 of a square inch in section, is kept at the proof strain by a tension of 

 25,000 lbs. . . ." 



We would much prefer to see this printed: "A rod of steel, 10 ft. long and 

 o'5 of a square inch in section, is kept at the proof strain in tension by a load of 

 25,000 lb. . . ." The o - 5 and lb. should be particularly noted. 



The suggested corrections are, after all, small, compared with the vast amount 

 of excellent work in the book, and we could wish that all text-books in use in 

 engineering colleges and schools were of the type of Elemeritary Applied 

 Mechanics. 



J. Wemyss Anderson. 



The Principles of Electrical Engineering and their Applications. Vol. I. 

 Principles. By Prof. Gisbert Kapp, M.I.C.E. [Pp. xii + 356, with 175 

 figures.] (London : Edward Arnold, 1916. Price15j-.net.) 



Much water has flowed under the bridge since the day when an engineer could 

 get along without knowing something about^electricity. Nowadays it comes within 

 the field of every engineer, from the builder of the Panama Canal, where a large 

 station has been erected to supply electrical power for operating the locks and all 

 the manifold electrical contrivances that are used for expediting traffic, to the 

 water engineer, who, as the preface suggests, " wants to know something about 

 the drop of potential along the rails of a tramway because the resulting earth 

 currents may eat up his pipes." 



This volume, to which a sequel is promised, is introductory. There is nothing 

 in it about any kind of electrical machinery. The most striking features of the 

 book are its directness, its " practicalness," and its conciseness. It sums up in 

 350 pages all the knowledge that any engineer wants of general electrical 



