232 



KNOWLEDGE. 



June, 1913. 



further light on the obscure subject of Magic, add very 

 greatly to the scientific value of the book. 



H. S. Redgrove. 

 PHYSICS. 

 Introductory Electricity and Magnetism. — By Carl W. 

 Hansel. 373 pages. 283 illustrations. 7i-in-X5-in. 

 (William Heinemann. Price 2/6 net.) 

 This book is obviously the work of an experienced 

 teacher, and deserves the careful consideration of all con- 

 cerned in preparing for 

 elementary examinations n 

 in this subject. The 4 // 



figures are excellent, and 

 there is a refreshing 

 absence of confused pho- 

 tographic reproductions. 

 At the end of each sec- 

 tion questions for revision 

 are given. 



W. D. E. 



Elementary Experi- 

 mental Dynamics for 

 Schools. — ■ By C. E. 

 Ashi-oru, M.A. 246 

 pages. 94 illustrations. 



7J-in.X5-in. 

 (The Cambridge Univer- 

 sity Press. Price 4/- net.) 



This useful little book 

 scarcely needs the 

 apology which the author 

 makes for it in his 

 preface. The principle 

 of approaching the study 

 of Kinetics by an induc- 

 tive method is now fairly 

 well established, and the 

 arguments for it are 

 recapitulated here. In 

 the text itself the 

 measurement of velocity 

 and of small intervals of 

 time is approached by 

 way of Fletcher's trolley 

 and vibrating paint- 

 brush, and the notion of 

 variable velocity is intro- 

 duced by distance-time 

 diagrams plotted from 

 Bradshaw on squared 



paper. The notions of force and of the relation between gravi- 

 tational and kinetic units of force are led up to by further experi- 

 mental work with the trolley and paint-brush. An experimental 

 verification of the formula for kinetic energy is new to us. The 

 chapter on Fluid Pressure is a link between the past and the 

 present of our Navy, as it deals with wind pressure on sails and 

 also with the Parsons steam turbine. Teachers of mechanics 

 will find many hints in this book, even if they cannot afford to 

 invest in all the apparatus which the British taxpayer supplies 

 to our naval colleges. W. D. E. 



YEAR BOOK. 



Directory of Museums in Great Britain and Ireland; 



together with a Section on Indian and Colonial Museums. 



— By E. Howarth, F.R.A.S., F.2.S., and H. M. Platnauer, 



B.Sc. 312 pages. 8i-in. X5^-in. 



(The Museums Association. Price 10/-.) 



We have received a copy of the Directory of Museums, 

 which gives briefly but in a very useful way much valuable 

 information with regard to the National and Local Institutions 

 of this country, as well as the more important Indian and 

 Colonial Museums. We learn who is responsible for the 

 various Museums, how they came into existence, what they 

 specially intend to illustrate, as well as what work of an 

 educational kind is carried out by the staff. The book should 

 be in every reference library. W. M. W. 



ZOOLOGY. 



Life and Evolution. — By F. W. Headley. 272 pages. 



98 illustrations. 8j-in.X6-in. 



(Duckworth & Co. Price 5/- net.) 



Based on lectures delivered to the natural history class at 



Haileybury College, this attractive volume was first presented 



to the public in 1906, and its reappearance in the form of a 



new and revised edition affords such testimony of its popularity 



that commendation on our part seems superfluous. 



Among the chapters 

 that have undergone 

 special revision are those 

 on flight, but when dis- 

 cussing (page 98) the 

 manner in which the 

 giant pterodactyles of 

 the secondary epoch 

 were enabled to sustain 

 themselves in the air, the 

 author appears to have 

 overlooked an important 

 paper published last year 

 in the Bulletin of the 

 Geological Society of 

 France, in which Messrs. 

 E. and A. Harle maintain 

 that without an atmos- 

 pheric pressure much 

 greater than at present 

 exists flight in the case 

 of these monstrous rep- 

 tiles would have been an 

 absolute impossibility. 

 He might also (page 141) 

 have referred to Sir 

 Hiram Maxim by his 

 proper title instead of 

 as Mr. Maxim. 



Some of the sentences 

 in various parts of the 

 work would also have 

 been the better for re- 

 vision, as is exemplified 

 by the unnecessary repe- 

 tition in the following 

 statement (page 89) : — 

 " The reptile that seems 

 to carry off the prize for 

 speed is an Australian 

 \izaid,Chlamydosaurus 

 kingi. Chi amy do- 

 saurus is an Australian lizard, being found in Queensland." 

 Apart from slight shortcomings of this nature, the book is 

 an excellent epitome of modern views on evolution. R. L. 



Deer Breeding for Fine Heads, with Descriptions of many 



Varieties and Cross Breeds.— By Walter Winans, F.Z.S. 



105 pages. 34 illustrations. ll-in.X9-in. 



(Rowland Ward. Price 12/6 net.) 

 The first object of Mr. Winans' book is to show that the 

 Deer should be looked after and bred as carefully as any 

 other animal which is kept in captivity. His illustrations 

 show how well he has himself succeeded. Incidentally, how- 

 ever, in the book an account is given of cross-bred deer, and 

 by the courtesy of the author we are able to show pictures of 

 the heads of the cross between the Wapiti and red deer as 

 well as between the Altai and red deer. Mr. Winans has 

 gone further and crossed a Wapiti-red- Deer hind with an 

 Altai stag, so that he has now Wapiti-Altai-red-Deer hybrids, 

 a cross which he believes has never before been attempted. 

 There is much of great interest and usefulness in the book, 

 and we may allude to the chapters on the preservation of 

 Horns ; on the precautions to be taken to avoid injury by Deer, 

 and with regard to the times of breeding. Artists should read 

 the notes on the action of Deer and take to heart what Mr. 

 Winans has to say about the drawing of animals. W. M. W. 



V the courtesy o/ Mr. Ktnclaiid Ward. 



FlGU 



Cross-bred Altai-red-Deer, from " Deer Breeding for Fine Heads. 



