March 15, 1906] 



NA TURE 



459 



design of reinforced concrete arches are taken up; 

 after a brief explanation of the elastic theory and its 

 application to the determination of the stresses in any 

 arch, Thacher's formulas for reinforced concrete 

 arches are given, and their use in practice explained 

 bv the help of three typical examples of such arches, 

 a highway bridge of two spans, each of 42J feet, a 

 single-line railway bridge of 72-feet span, and, lastly, 

 a small semicircular arch culvert of 15 feet span. 

 These three examples are completely worked out, the 

 necessary graphical constructions being shown in full 

 in three plates ; this chapter will undoubtedly be 

 found very useful to any engineer who is engaged in 

 the design of such arches. 



Parts ii. and iii. are the work of Mr. Hill, and 

 deal respectively with representative structures and 

 methods of construction ; the following branches of 

 work are dealt with : — foundations of various types, 

 including reinforced concrete piles, floors, walls and 

 arches in buildings, and columns. The illustrations 

 selected, though largely American, include also a 

 number of cases of work carried out in Europe on 

 the Hennebique system. The application of reinforced 

 concrete to large bridges and culverts is illustrated by 

 a number of structures which have recently been put 

 up in France on the Monier system, and it may be 

 pointed out that some hundreds of bridges of this 

 type have now been erected, principally in Germany 

 and Austria. 



The last section of the book, on methods of con- 

 struction, is naturally largely taken up with the de- 

 M'ription of the various forms necessary in elaborate 

 reinforced concrete work. The future security of the 

 work depends entirely upon the care with which the 

 forms are designed and erected, and the economy of 

 the work is largely dependent upon forms so designed 

 that they can be rapidly put into position, readily 

 taken down, and readily re-erected on a fresh section 

 of the work. Many valuable hints and labour-saving 

 suggestions will be found in this portion of the book. 

 The author has evidently based this section upon ex- 

 perience of a very varied character in the erection of 

 reinforced concrete structures. 



(5) This is another of the somewhat numerous text- 

 books which have appeared within the last few- 

 months dealing with the important subject of rein- 

 forced concrete. The author points out that the use 

 of steel merely embedded in stone or concrete, as in 

 the well known skeleton system of construction, does 

 not develop the best properties of each of these 

 materials — reinforced concrete alone enables full 

 advantage to be taken of the special qualities of both 

 the steel and the concrete. 



The first portion of the book deals with the physical 

 properties of the two materials, concrete and steel, 

 and a number of carefully selected tables is given 

 of tests of these materials. The general theory of 

 concrete-steel beams is then considered, and special 

 emphasis is laid upon the necessity of an accurate 

 knowledge of the moduli of elasticity. 



We are afraid, however, that the author has fallen 

 into confusion of thought in discussing the question 

 of the position of the neutral axis ; on p. 43 he refers 

 NO. 1898, VOL. 73] 



to an imaginary beam of concrete and steel, and 

 appears to consider that each square inch of the con- 

 crete will carry the same total stress, ignoring 

 altogether the variation in intensity of stress with 

 distance from the neutral axis; and again, in 

 chapter iv. , when discussing the position of the 

 neutral axis, he states that the position of this is 

 affected by the fact that the compressive strength 

 of the material (concrete) is greater than its 

 tensile strength. Surely there is confusion here 

 between strength and modulus of elasticity, and this 

 confusion seems to run through all the rules and 

 calculations for the position of the neutral axis. This 

 portion of the book certainly requires to be carefully 

 revised if it is to become a trustworthy text-book on 

 the subject. 



The subject of floor design in concrete and steel is 

 taken up, several large floors constructed on the 

 Hennebique system are fully described, and tables are 

 given of working stresses which can be allowed, and 

 the building rules which have been laid down by 

 various authorities in connection with the design of 

 such floors. The application of reinforced concrete 

 to foundation work in bad soils is discussed, and the 

 author shows that by the use of this type of construc- 

 tion the depth to which the foundation must be taken 

 can be very considerably reduced. The last chapter 

 discusses the construction of reinforced concrete 

 columns, special attention being given to Considered 

 hooping method. 



CHEMISTRY FOR SCHOOLS. 

 Notes on Volumetric Analysis. By J. B. Russell and 



A. H. Bell. Pp. viii + 94. (London : John Murray.) 



Price 2S. 

 Introduction to Chemical Analysis. By Hugh C. H. 



Candy. Pp. xii+114. (London: J. and A. 



Churchill, 1905.) Price 3s. 6d, net. 

 An Elementary Text-book of Inorganic Chemistry. 



By R. L. Whiteley. Pp. viii + 245. (London: 



Methuen and Co.) Price 2s. 6d. 

 Elementary Chemistry, Progressive Lessons in. By 



F. R. L. Wilson and G. W. Hedley. Pp. xii+168. 



(Oxford : The Clarendon Press, 1905.) Price 35. 

 A Three Years' Course of Practical Chemistry. By 



George H. Martin and Ellis Jones. Pp. viii4-ii2. 



(London : Rivingtons, 1906.) Price 2s. 

 T T seems to have become a recognised practice for 

 -1- schools and colleges to produce their own small 

 text-books or notes on some portion of the science cur- 

 riculum, first for internal use, and then for the benefit 

 of outsiders. Whether this multiplication of little 

 books is desirable is somewhat questionable. With- 

 out going so far as to say that these small books 

 conduce to cramming or getting through examin- 

 ations, there is always a slight lurking suspicion about 

 this point. Our various " examination " boards are 

 perhaps answerable for the small book production. 



Mr. Russell's book is intended, no doubt, for use 

 on the working bench. The directions for working 

 are short, mainly to the point and in logical 

 order, but surely they are too frequently repeated. 



