332 



NATURE 



[September i6, 1909 



sounder basis to rest upon. The book contains two 

 beautiful photograpiiic plates of active volcanoes, and 

 a large number of useful illustrations ; in print, paper, 

 and binding it will meet the approval of every book- 

 lover. J. S. F. 



A POPULAR MAMMAL BOOK. 

 Wild Beasts of the World. By Frank Finn. 

 Pp. viii+i8S; illustrated. (London and Edin- 

 burgh : T. C. and E. C. Jack, 1908-9.) Price 175. 

 net. 



THE favourable opinion we formed of Mr. Finn's 

 work when the first part was noticed last year 

 "in Nature we are pleased to be able to endorse now 

 •^that the complete volume is before us. The book is 

 •confessedly a thoroughly popular one, and, therefore, 



• ought to be judged solely from that standard ; and 

 from that point of view it may be pronounced a de- 



• cided success. The author's style of writing is bright 

 and attractive ; and in the main his descriptions 

 appear correct and up to date. Mr. Finn has not 

 overloaded his text with names of naturalists and 

 observers about whom the public knows little or 



-nothing; and he has, in our opinion for the most 

 part rightly, altogether ignored subspecies. As 

 regards nomenclature, the author will liave nothing 

 to do with modern innovations and changes, and we 

 'accordingly find the baboons (and not the flying- 

 lemur) appearing under their old title of Cyno- 

 cephalus, and the fo.K as Canis viilpes. The fact that 

 •such names still dominate in popular literature sug- 

 -gests that they should not, as is now too much the 

 'fashion, be ignored in our museums, which are 

 ■primarily popular institutions. 



Mr. Finn appears to take as his texts the hundred 

 mammals represented in the coloured plates, as the 

 descriptions of all these are printed in larger type 

 -than is conceded to many of the others noticed. Per- 

 sonally we are not enamoured of this plan, as it 

 suggests that the species to which large type is 

 accorded are of more importance than the rest; but 

 this point is not one affecting the character of the 

 work as a whole. 



The coloured plates form, of course, the charac- 

 teristic of the volume which will appeal most 

 strongly to the general public; and for these illus- 

 trations — the only ones in the book — we have in the 

 main nothing but commendation, although some 

 appear rather too brilliantly coloured. A few, more- 

 over, do not indicate important details— notably the one 

 ■of the hamster, in which the dorsal gland-patch is 

 not shown. The one serious error in the illustrations 

 ■occurs in part xii., where the plate lettered Marco 

 Polo's wild sheep really represents the true argali 

 {Ovis ammon) ; and there is no excuse for this, as 

 the figures, if we mistake not, have been drawn from 

 the mounted specimens in the British Museum. Nor 

 is this all, for, whereas the figure in the foreground 

 depicts, as we have said, the true Altai argali, the 

 one in the middle distance is taken from its Tian 

 Shan representative. In the concluding part we 

 notice that the plate of the platypus shows the web 

 NO. 2081, VOL. 81] 



of the forefoot fully extended when the animal is on 

 land, in place of being folded beneath the palm, as 

 it must be in order that the creature should get a 

 foothold. 



Misprints and other errors in the text appear to 

 be few, but we notice on p. 47 Mipsiprymmis for 

 hypsiprymnus. In the account of the Derbian eland 

 no mention is made of the fact that the species 

 occurs in the Bahr el Ghazal ; while the occurrence 

 of the water-chevrotain in East Central Africa is 

 ignored. The old error as to female takin-horns 

 differing in form from those of the male is also re- 

 peated. 



Most of these are, however, but trifling errors, 

 which detract but little from a work worthy in the 

 main of high praise. R. L. 



APPLIED MECHANICS. 

 (i) Applied Mechanics for Engineers. A Text-book for 



Engineering Students. By E. L. Hancock. Pp. xi + 



385. (New York: The Macmillan Co., 1909; 



London : Macmillan and Co., Ltd.) Price 8s. 6d. 



net. 

 (2) Machines — Outils, Outillage, Verificateurs. By 



P. Gorgeu. Pp. 232. (Paris : Gauthier-Villars, 



1909.) Price 7 francs, 50 centimes. 

 (i) ' I "HIS book is intended to be a text-book for 

 -L engineering students during the first year 

 of their course, and the examples selected to illustrate 

 the principles discussed are, therefore, mainly such as 

 are likely to be met with in practical engineering 

 work. To facilitate the working out of the numerical 

 problems, of which there are nearly 300 scattered 

 through the book, the author has printed in the form 

 of five appendices a series of tables including hyper- 

 bolic functions, logarithms of numbers, trigonometri- 

 cal functions, squares, cubes, square roots, conversion 

 tables, &c. ; it is very problematic as to how often such 

 tables incorporated in a text-book are of use to the 

 student — it is much more convenient for him to have 

 a small thin book of mathematical tables, and there 

 are several such books now available, which he can 

 carry about with him in his pocket, and refer to 

 whenever calculations have to be made. 



Two very complete chapters are those devoted to 

 centre of gravity and moment of inertia; the applica- 

 tion of Simpson's rule to the finding of the area and 

 centre of gravity of rail and similar sections is fully 

 discussed, and the whole subject of the determination 

 of moments of inertia of various standard sections is 

 treated very fully, both by analytical and graphical 

 methods : this is a matter of considerable interest to 

 engineers engaged in structural design work. 

 Another chapter which will be found of use by the 

 engineer in practice as well as by the young student 

 is that dealing with the dynamics of machinery : after 

 dealing with such usual problems as those of the 

 flywheel and connecting-rod in a reciprocating engine, 

 a number of sections is devoted to the gyroscope, and 

 to its application to the mono-rail and similar 

 devices. 



The last chapter in the book treats of impact in a 



