364 



NATURE 



[August 16, 1883 



man works under the Japanese Government. Many of 

 these are exceedingly irritating, among them being the 

 incompetence and presumption of native colleagues, who 

 are fond of proceeding in what Mr. Holtham styles "the 

 rough and ready heaven-born-genius-and-see-it-with-half- 

 an-eye kind of way" in cases where his old-fashioned 

 education led him to seek first carefully for facts. The 

 author pfsses over unpleasantnesses such as these in a 

 very kindly way, but there can, we believe, be no question 

 that many most important elements of the true scientific 

 spirit are sadly lacking in young Japan. Energy, thirst 

 for knowledge, and ingenuity exist in abundance, but we 

 are not so assured of the patience, and caution in research, 

 and respect for the opinions of older and more experienced 

 heads, which are also necessary. Hence, doubtless, we 

 find so many promising schemes come to nought. It is 

 more satisfactory to find that, in Mr. Holtham's opinion, 

 the students who have been so carefully trained under 

 excellent foreign teachers in the Imperial College of 

 Engineering give great promise of subsequent practical 

 usefulness. The foreign staff of the Japanese Railway 

 Department has now been almost wholly replaced by 

 natives, and it will be very interesting to watch the 

 Japanese walking alone. A few years will s' ow how far 

 they were justified in getting rid of the men to whom they 

 owe their substantial public works. However this may 

 be, we can cordially recommend " Eight Years in Japan" 

 as a very interesting and amusing book. 



ELEMENTARY APPLIED MECHANICS 

 Elementary Applied Mechanics. Part II. By Thos. 

 Alexander, C. E., and Arthur Watson Thomson, C.E., 

 B.Sc. (London : Macmillan and Co., 1883.) 



IN this volume the authors have pursued the same 

 course as that followed by Prof. Alexander in the 

 first volume of his "Elementary Applied Mechanics," in 

 giving an abundant commentary, illustrated by a large 

 number of practical examples, of those parts of Rankine's 

 " Applied Mechanics'' which deal with transverse stresses 

 and the shearing forces and bending moments on beams 

 and cantilevers. 



They have thus supplied a want which has long been 

 felt both by teachers and students of a text-book which 

 should treat applied mechanics in a way similar to that 

 pursued in mathematical works. 



The work before us is accurate and clearly written, and 

 the explanations given are so full that it may be easily 

 understood by any one whose mental powers are not so 

 hopelessly deficient that he would be liable to incur re- 

 sponsibility for culpable homicide if he were to under- 

 take to design or construct a bridge, or any sort of struc- 

 ture in which defects might be attended with risk to 

 human life. 



Thoroughly penetrated with the scientific spirit of Ran- 

 kine's work, though happily with a more perfect acquaint- 

 ance with the limits of average human intelligence, the 

 authors have given at length the proofs of the formula: 

 belonging to this part of applied mechanics, and they 

 have al~o examined carefully the various cases which 

 occur owing to the different modes of loading a beam. 



The results arrived at and the methods employed, 

 many of which are new, have, in each case, been rendered 

 more easy of apprehension by the addition of a solution 



of the same question by simple graphical methods, nearly 

 all of which depend, by a proper change in the scale on 

 which vertical ordinates are measured, on the use of an 

 invariable parabolic segment which is to be carefully 

 constructed beforehand in wood or cardboard, and em- 

 ployed throughout. 



By this means complicated questions on beams with 

 both a dead and travelling load, can be easily dealt with, 

 and the curves of bending moment and maximum 

 bending moment readily drawn. 



The mathematics employed are of the simplest character, 

 not extending, except in one or two instances, beyond 

 elementary algebra, whilst those properties of the para- 

 bola which are employed are previously proved in the 

 form of lemmas. 



But excellent as is the theoretical exposition of prin- 

 ciples in the book, we are disposed to attach even greater 

 importance to the large collection of examples scattered 

 through it, in which the facts and formula? of the text are 

 applied to well chosen practical examples. 



It has been a great misfortune, which all teachers of 

 the subject have deplored, that the writers of books on 

 it have spared themselves the labour of compiling a set of 

 numerical examples, which would enable students to 

 obtain that grasp of it which examples alone can give, 

 and at the same time afford them the assurance that the 

 formula they have been studying have some practical 

 significance. 



Those which are scattered through this work are 

 judiciously selected, and they are accompanied, when 

 necessary, by hints for their solution. We set a high 

 value on this feature of the book, and we believe that a 

 student, even though otherwise unassisted, who should 

 carefully read it and conscientiously work through the 

 examples, would acquire a knowledge, theoretically sound 

 and practically useful, of this part of applied mechanics 

 which he could not gain with the same labour and in the 

 same time from the study of any other book which has 

 been published on the subject. J. F. Main 



OUR BOOK SHELF 



Text-Book of Physics. By J. D. Everett, M.A., D.C.L., 

 F.R.S. Illustrated. (Glasgow : Blackie and Son, 1883.) 



This book of 300 pages well fulfils the author's intention 

 of providing an elementary text-book which may especially 

 serve as an introduction to the well-known work of 

 Deschanel with which his name is associated. It is full 

 of matter, which is presented to the reader in a thoroughly 

 systematised and acceptable condition. 



The definitions, we need hardly say, are excellent and 

 well worthy of the reputation of one who has taken a 

 prominent part in scientific definition and terminology. 

 Indeed we have rarely seen the chief points of scientific 

 interest so clearly explained as they are in this volume. 

 We give the following as a good illustration (p. 119) : — 

 ' ' Fuel is a reservoir of potential energy, inasmuch as 

 its elements are ready, whenever opportunity is given, to 

 unite with the oxygen of the air and develop a large 

 amount of heat. The words 'whenever opportunity is 

 given ' require some explanation. ... If we have a large 

 stone lying near the edge of a precipice 1000 feet deep, 

 the stone will not move over of itself, but is ready to fall 

 when opportunity is given, and a trifling expenditure of 

 work in moving the stone to the edge will enable it to 

 descend to the foot with terrific violence. ... In the 

 firing of a gun there is a combination of illustrations of 



