April i6, 190SJ 



NA TURE 



555 



Instructions could be materially improved. The 

 anatomical facts are clearly stated considering that 

 this part of the subject is much more advanced than 

 the rest of the book. But speaking generally, the 

 author has aimed at brevity, and in so doing has 

 sacrificed exactness ; this is specially noticeable in 

 the course of external morphology, where several 

 mistakes and incomplete definitions occur. 



The short introduction to elementary botany planned 

 by Miss Laurie is a direct antithesis to the last, as 

 the facts recorded are few, but they are deduced or 

 suggested so as to arouse interest and stimulate 

 experiment and thought. Written primarily for quite 

 small children, it shows how facts in the life-history 

 of plants may be taught from simple experiments, 

 such as the growth of mustard seeds in a bottle In 

 addition to morphology and the accompanying 

 physiologv, there are chapters on interrelation between 

 plants and animals, climbing plants and colours oi 

 plants, .\lthough the information is couched in a 

 form understandable by young children, the book 

 could be advantageously adopted as a first course for 

 older children, and might be profitably consulted by 

 many teachers as a guide to imparting instruction. 



The observation of trees and shrubs is preeminently 

 suited for a nature-study class, and possesses the 

 advantage that there is much to be noted even during 

 the winter months. A short, concise manual or 

 primer at a modest price is an existing desideratum. 

 The volume written by Mr. Coleman compasses the 

 subject and certainly sells at a modest price, but it 

 fails to satisfy the want alluded to. The author has 

 culled much interesting information of a general and 

 historic nature, but there is an almost entire absence 

 of the numerous botanical features of interest, such 

 as winter buds, arrangement of leaves, &:c., and for 

 identification the reader is mainly dependent upon the 

 illustrations. The notes on animals and insects 

 haunting the various trees and shrubs are so useful 

 that one wishes the author had given more space to 

 these facts of natural history. A list of British 

 lepidopterous insects the caterpillars of which feed on 

 certain plants is provided in an appendix. 



APPLIED MATHEMATICS. 



(]) Computation and Mensuration. By P. A. Lambert. 



Pp. ix-l-92. (New York : The Macmillan Co. ; 



London : Macmillan and Co., Ltd., 190;.) Price 



35. 6d. net. 

 (2)" .4 First Statics. By C. S. Jackson and R. M. 



Milne. Pp. viii + 380. (London: J. ^L Dent and 



Co., 1907.) Price 4.';. net. 

 (3) Practical Calculations for Engineers. By C. E. 



Larard and H. .\. Golding. Pp. xiii-l-455. 



(London : C. Griffin and Co., Ltd., 1907.) Price 



6s. net. 



(1) ' I "HE author says that the boys in the secondary 



-«■ schools of .America are not taught to apply 



their mathematics independently, and consequently 



find, on entering college, that they have difficulty in 



NO. 2007, VOL. 77] 



making effective use of their theoretical knowledge, 

 and this book is intended as a link between the school 

 and college courses, to be studied either at the end 

 of one or the beginning of the other. 



The same deficiency is manifest in boys leaving our 

 schools, and in this country is being met by im- 

 proved teaching combined with practical work .in 

 the laboratory, as a regular part of the school 

 course. 



The book is admirably planned and written, is 

 concise, neat in method and interesting, and meets 

 a real want in a worthy manner. It begins with 

 examples of direct measurement, approximate 

 numbers, and contracted arithmetic, estimating the 

 degree of accuracy by the number of decimal places ; 

 perhaps the number of significant figures would have 

 been better. This is succeeded by examples of prac- 

 tical geometry, including the construction and 

 measurement of triangles, and some squared-paper 

 work. Then follows the volume of a prismatoid, and 

 in later chapters on mensuration it is shown that the 

 prismoidal formula, or Simpson's rule, is widely ap- 

 plicable. There is a useful chapter on trigonometrical 

 computation, introducing very appropriately the 

 notion of a vector with examples of vector summa- 

 tion. Logarithms and the slide rules are next con- 

 sidered, followed by an interesting- chapter on limits, 

 illustrated by several important convergent series. 

 The author always seizes on the salient points, is 

 never prolix, and the interest never flags; in each 

 chapter the student is well started on his way, then 

 provided with good and suggestive examples, and 

 wisely left to his own resources. Thus, although the 

 pages of the book are comparatively few, the usual 

 ground is covered, and a thorough and efficient train- 

 ing in practical computation is provided. English 

 teachers would do well to consult this work. 



(2) This text-book proceeds on easy lines, and the 

 student is provided with a wealth of examples 

 at every stage from which to choose, the answers 

 being collected at the end of the volume. In their, 

 scheme the authors have considered " the historical 

 order of development of the subject, as indicating 

 almost infallibly the line of least resistance." Thus 

 in the first chapter the principle of the lever is intro- 

 duced, and the law of moments for parallel forces is 

 established by simple experiments, then illustrated by 

 examples of ancient and modern steelyards and 

 balances, and finally applied to find the conditions of 

 equilibrium of three parallel forces in a plane. The 

 next two chapters deal with the parallelogram law 

 for forces at a point, the treatment being here again, 

 as always, experimental, graphical, and analytical, 

 with examples of useful applications in the arts. It is 

 not quite clear why the authors should substitute the 

 term "geometric" addition for vector addition, or 

 why arrow-heads should " sometimes " instead of 

 always be inserted in vector diagrams. In chap- 

 ter iv. the principle of moments is again con- 

 sidered, being now deduced from that of the parallelo- 

 gram and applied to couples. Then follow sections 

 dealing with machines, friction, and centres of 



