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LXI1. Notices respecting New Boohs. 



A Treatise on Analytical Statics, with numerous examples. By 

 E. J. Eouth, F.H.S. Vol. II. (Cambridge University Press, 

 1892: pp. xii + 224.) 



T) EADERS of Dr. Eouth's first volume were told in the preface 

 xv to that work th^t he "felt that such subjects as Attractions, 

 Astatics, and the Bending of Eods could not be adequately treated 

 at the end of a treatise without making the volume too bulky or 

 requiring the other parts to be unduly curtailed. These remaining 

 portions will appear in a second volume." No long delay has 

 intervened, and the book before us treats the above-named subjects 

 in the author's usual clear aud graphic manner and completes, we 

 presume, what Dr. Eouth proposes to publish on the matter of 

 Statics. The main portion of the work (126 pages) is devoted to 

 the interesting branch of Attractions. As the author points out, 

 " The reasons for believing the truth of the general law," which is 

 the fundamental one in the subject, "cannot be properly ex- 

 plained until the reader has advanced some way in the study of 

 Dynamics. At the same time a large number of theorems which 

 are independent of all dynamical considerations follow from this 

 law. Experience has shown that it is important for the student to 

 acquire an early acquaintance with these results, as he cannot 

 prosecute his studies in the higher Dynamics without their assist- 

 ance. It has therefore been found advantageous to study the 

 attractions of bodies as a part of Statics. Eor this purpose we 

 assume the truth of the law of attraction as a working hypothesis 

 and postpone its verification as a law of nature until the student 

 has read Dynamics." It is superfluous to examine in any detail 

 such an exhaustive account as this is, seeing that every student of 

 the subject, if he has not enjoyed a viva voce exposition of it from 

 the author, should strive to master its contends. All previous 

 writers seem to have been laid under contribution and, with 

 scrupulous care, each important result is assigned to its fi~st 

 discoverer. This citation of original authorities we have, in 

 previous notices of Dr. Eouth's works, had occasion to commend. 

 A further excellent feature in the present case is the full Index at 

 the end in addition to a fairly exhaustive table of contents. The 

 object of the chapter on the Bending of Eods is " to discuss the 

 stretching, bending, and torsion of a thin rod or wire." It closes 

 with a section on Eods in three dimensions. The final chapter, 

 on Astatics, opens with an historical note which states that the 

 subject seems to have been first studied by Moebius, in his 

 LeJirbuch der Statik, 1837. Indexes are furnished to the last two 

 chapters, and the whole of the text bears evidence to the extreme 

 care with which it has been drawn up. This is to be accounted for 

 on the ground that both volumes are the outcome of many years' 

 lectures (see preface to vol. i.). 



