REVIEWS 163 



and "Heat Radiation," and in some respects his views on certain points have 



changed of late, but the lectures present in bold outline the most important 



advances in the present System of Physics. 



J. Rice. 



Exercises in Practical Physics. By A. Schuster, Sc.D., Ph.D., and C. H. 

 LEES, F.R.S., D.Sc. Fourth Edition revised. [Pp. x + 379.] (Cambridge: 

 at the University Press. Price ys. net.) 



THE work, of which this is the fourth edition, already enjoys a well-deserved 

 reputation among teachers of Physics for the clear descriptions which it contains 

 of a large body of carefully selected experiments. The additions to the material 

 of the first edition are as follows : 



(1) A fuller account of the measurement of the magnifying power of a micro- 

 scope. 



(2) A description of an alternative fonn of water voltameter. 



(3) Some remarks on the measurement of thermoelectric power. 



(4) An appendix on the determination of dip. 



The development of formulae has been modified here and there, while an 

 account of the preparation of a Weston Standard Cell replaces the account for a- 

 Clark Cell of the earlier edition. 



Students who have already obtained an elementary knowledge of Physics will; 

 find in this book an excellent guide to the principles and methods of accurate 

 measurement. The instructions are complete, and there is a useful appendix 

 giving details as to design and dimensions of suitable apparatus. 



J. Rice. 



Introduction to Heat. By A. R. Laws, B.Sc, and G. W. Todd, D.Sc. [Pp. 

 x + 212, with 106 Diagrams.] (London : Mills & Boon. Price is. 6d.) 



THIS little volume is designed as a text-book and a laboratory manual for 

 beginners. The authors state that, as boys are gifted with a large amount of 

 curiosity which they endeavour to satisfy, an appeal is constantly made in the 

 book to ordinary experience, so that pupils may realise that there is a great deal 

 to enquire about in the phenomena of everyday life ; experiments are designed to 

 elucidate these experiences, others are suggested with the object of inducing a 

 frame of mind in which the pupil will " ask for more.'' 



As far as the writer can judge, the authors should attain their object. The 

 choice and arrangement of the subject matter is excellent. The explanations are 

 lucid and ample. The diagrams — 106 in number — are clearly and carefully 

 drawn ; while there are numerous problems and examples to test the student's 

 progress. 



J. Rice. 



X-Kays. By Capt. G. W. C. Kaye, M.A., D.Sc. [Pp. xxii + 285, with 

 114 diagrams and illustrations. Second, revised and enlarged, edition.] 

 London : Longmans, Green & Co., 1917. Price gs. net.) 



That a second edition of this handbook should be called for so soon is not sur- 

 prising in view of the vast increase in the number of X-ray operators called into 

 being by the war, though it would probably have been required in any case ; for, 

 by adding an account of the Braggs' and of Moseley's experiments while the first 

 edition was in course of preparation, Capt. Kaye made it indispensable to all 

 workers in the new field. It still remains unchallenged as the best complete 



