532 SCIENCE PROGRESS 



already existing data had been critically examined, it appeared desirable to carry 

 out a more comprehensive experimental investigation. Throughout the whole 

 work we have been indebted to Prof. Miller for his advice and support." 

 Needless to say, the comprehensive tables published at the end of the book as 

 the outcome of such work may be accepted by refrigerating engineers as 

 representing the latest and best results. 



Scientists, as a body, will be interested in the thermo-dynamical portion of 

 the work. Mr. Brownlee's results on the specific volume of liquid ammonia are 

 so different in the extreme values as to give quite a different form of curve from 

 that obtained from the plotted results of Dieterici and Lange. In the main 

 Mr. Brownlee's figures are practically a mean, but the whole question is so 

 important that it should attract other investigators. 



The authors have had a very great advantage in having the critical investiga- 

 tion of Goodenough and Mosher on the "Properties of Ammonia" {Bulletin 

 No. 66, University of Illinois, 191 3) beside them and have not failed to compare 

 equations, methods, and results. The methods of attack are, in the main, very 

 different, and without detracting in the very least from the earlier work, we must 

 say the present work carries conviction with it. 



We particularly commend the sound judgment of publishing all the records 

 in the C.G.S. units and the tables in British units. The working engineer both 

 in U.S.A. and Great Britain uses the latter set of units — in their own good time 

 they will use the C.G.S. We have seen recent volumes intended for engineers — 

 some wholly in C.G.S., others in centigrade-pound, and others wholly in British 

 units. Which is best ? The authors apparently think all three are open to 

 question and supply a fourth, i.e., the scientific work in C.G.S. and the utility 

 side in those units employed by the user. We agree with the authors and think 

 it points a lesson to the whole Empire. 



J. Wemyss Anderson. 



Elementary Applied Mechanics. By T. Alexander, C.E., M.Inst.C.E.I., 

 M.A.I., and A. W. Thompson, D.Sc. [Pp. xx + 512, with numerous 

 diagrams.] (London : Macmillan & Co., 1916. Price \$s. net.) 



This work, although it is called Applied Mechanics, deals only with a fraction of 

 the subjects usually scheduled under this title — i.e., with the " theory and design 

 of structures," together with the necessary introduction, " strength of materials." 

 Further, the book may well serve as a text-book for the undergraduate in engi- 

 neering science during his college career, and therefore the term "elementary" 

 does not imply that it is a suitable text-book for students in evening classes in their 

 first year. 



The subject-matter, from the first chapter on " Lineal Stress and Strain " up to 

 Chapter XXII on the " Scientific Design of Masonry Arches," is dealt with, step 

 by step, in masterly style. 



The authors are clearly masters of their subject, and this allows them to 

 develop theories, such as Rankine's method of conjugate load areas when dealing 

 with the equilibrium of arches, and to introduce new methods of treatment and 

 also, further, to freely quote methods of solving particular problems developed by 

 others, and which, the authors feel, merit inclusion in their work. A good example 

 of this is to be found in Chapter XIX on " Long Steel Struts," where Fidler's 

 excellent method of design is quoted and tables given. 



The book is altogether refreshing after the very stereotyped methods followed 

 in most text-books. 



