376 SCIENCE PROGRESS 



The fifth and sixth chapters are devoted respectively to the transmitting and 

 receiving instruments employed. It may be said at once that the matter is dealt 

 with throughout in an elementary and instructive manner, and entirely fulfils the 

 object of the writer. One excellent feature is the clear way in which the processes 

 of wireless telegraphy are made more simple by analogy with hydraulics, though 

 in a future edition the picture of the hydraulic model of a condenser should be 

 re-drawn with a little more care in order to make clear which are the pipe 

 arrangements and which are the cylinders. 



Continuous Beams in Reinforced Concrete. By Burnard Geen, A.M.I.C.E., 

 M.S.E., M.C.I. [Pp. 210, illustrated.] (London : Chapman & Hall, Ltd., 

 1913. Price gs. net.). 



The subject-matter of this volume is rather more limited in its scope than the 

 title would lead one to expect, consisting as it does chiefly in a series of diagrams 

 and tables dealing with the theoretical Bending Moments, Shears and Reactions 

 in continuous beams of reinforced concrete, and their supports, though the results 

 are in general equally applicable to any other form of continuous girder. 



The aim of the author is to place in the hands of the designer of such structures 

 as warehouses and other buildings in which a great many of such reinforced 

 concrete beams are employed a set of tables from which he can deduce by a 

 simple operation the Bending Moments, Shearing Forces and Reactions for any 

 system and any intensity of dead and live loads, thus avoiding the laborious 

 calculations entailed on the application of the Theorem of Three Moments to each 

 individual case. This end is accomplished fairly comprehensively by reducing to 

 standard spans and intensities of loads. 



All results are calculated from a consideration of the General Theorem of 

 Three Moments, which is enunciated and proved in a clear manner in Chapter II. 



There is a wealth of diagrams covering almost every possible case of loading 

 over 2, 3, and 5 spans, and on a scale sufficiently large to be of use ; but it would 

 be of advantage if a few words of explanation were appended to some of them, as 

 it is now necessary to count the number of spans in diagrams 1 to 39 in order to 

 ascertain which case is being treated. 



There are short chapters dealing with the utility of haunches in coping with the 



excessive negative Bending Moments at supports, the effects of support subsidence 



on the stresses in the beams, etc., and interesting paragraphs on the insufficiency 



wL"* . . 



of the usual formula recommended by the Institution of British Architects 



12 



for the Bending Moments at centres of spans and supports in the case of rigid 



beams on rigid supports, and on the extent to which the columns may be assumed 



to withstand bending. Examples of the method of application of the tables are 



given, from which it appears that the necessary calculations are very simply made ; 



and no doubt this work will find its place in the drawing offices of those who are 



engaged in the design of this increasingly important class of structure. 



Man and His Forerunners. By Prof. H. von Buttel-Reepen ; authorised 



translation by A. G. Thacker. [Pp. x + 96, 8vo, with a frontispiece, 



70 figures in the text, and 3 tables.] (London : Longmans, Green & Co., 



I9I3-) 



The last few years have witnessed a tremendous growth of interest in the 



earliest remains of mankind. This no doubt has been due partly to the normal 



