NATURE 



[January i6, 19 13 



trachytes, tuffs and other volcanic rocks which play 

 an important part in Europe. Copious lists of 

 American references are given, as well as statistics 

 of production quoted from official publications. 



In another edition, "White Man's Field, Red 

 Man's Field and Yellow Man's Field," misquoted 

 on p. 159 from Beare's table, should be trans- 

 formed from their present "Wild West" state into 

 the more readily recognisable "\\'hite Mansfield 

 Stone," etc. 



PHYSICS FOR CHILDREN AND STUDENTS. 



(i) The Boy's Play'book of Science. By John Henry 

 Pepper. Revised, rewritten, re-illustrated with 

 many additions by Dr. John Mastin. Pp. x-l-680. 

 (London : George Routledge & Sons, Ltd. ; New 

 York : E. P. Button & Co.) Price 5.?. 



(2) Examples in Applied Electricity. By C. G. 

 Lamb. Pp. iv + 6i. (Cambridge: The Uni- 

 versity Press, 1912.) Price 2S. 6d. net. 



(3) Manualc di Fisica ad Uso delle Scuole Secon- 

 darie c Superiori. \'olume Primo. Meccanica. 

 By Prof. Bernardo Dessau. Pp. xii-f-soo. 

 (Milano : Societa Editrice Liljraria, 1912.) 

 Price 12 lire. 



TO say that t 

 would in 



a sense be true, but might at 

 the same time be misleading. If the term be used 

 it must be qualified by saying that the remarkable 

 features are mainly undesirable. No doubt the 

 object of the book is commendable, for no one 

 denies that it is an excellent thing to interest youth 

 in the wonders of natural phenomena, and, further, 

 that the treatment should be as comprehensive 

 as possible. At the same time, it is surely better 

 to explain a few things well than to give loose 

 and inadequate explanations of many. 



In this respect the book in question is not at all 

 successful. A verj' large number of phenomena 

 are dealt with in a manner which is often too 

 cursory to jje clear, and is sometimes, indeed, 

 actually erroneous. Thus in treating the subject 

 of gravitation the author, after regretting the 

 fact that there are not many good lecture-table 

 experiments illustrating' this effect, goes on to 

 say that " attention may be directed to the fact 

 oi a piece of potassium thrown on the surface of 

 water in a plate generally rushing to the sides, 

 and, as if attracted, attaching itself with great 

 force to the substance of the pottery or porcelain." 

 Although not an absolute statement of fact, this 

 is at least a suggestion that the movement is the 

 result of gravitational attraction between the 

 potassium and the sides of the vessel. The N 

 rays of Prof. Blondlot are spoken of as though 

 NO. 2255, VOL. 90] 



their existence had never been disputed, and heat 

 is spoken of as a force. 



Another curious feature is the order in which 

 the various subjects are taken. For some un- 

 accountable reason a chapter an aerial flight — in 

 which several pages are wasted upon an absurd 

 and unnecessarily long list of persons who have at 

 various dates been killed in attempting to fly — 

 is sandwiched in the section on chemistry between 

 the liquefaction of gases and the halogens. 



It should be said that the contents of the book 

 are limited to the consideration of the science of 

 inanimate objects, and undoubtedly convey much 

 useful information. Nevertheless, the weaknesses 

 which have been referred to above render it im- 

 possible to bestow upon the book any hearty 

 recommendation. 



(2) The author of this little volume has com- 

 piled, mainly from test papers set to the students 

 in the Cambridge Engineering Laboratory and 

 from the papers in the Mechanical Science Tripos, 

 a considerable number of numerical questions in 

 electrical engineering. They are arranged in the 

 form of papers of some eight questions each, and 

 the answers are given at the end of the book. 

 The questions are varied in character and, although 

 they do not include the subjects of polyphase 

 currents and wireless telegraphy, should prove 

 very useful in engineering schools. 



(3) This first volume of Prof. Dessau's Manual 

 of Physics includes rather more than what is 

 usually denoted by the title of " Mechanics " in 

 England. Besides the ordinary mechanics of 

 solids and fluids we find treated in an elementary 

 manner — as, indeed, is the whole book — such 

 phenomena as gravitation, elasticity, diffusion of 

 gases, and the interference of waves. The book is 

 exceedingly well printed and the diagrams are 

 uniformh' ijood. 



OUR BOOKSHELF. 



Science from an Easv Chair. Second Series. Bv 

 Sir Ray Lankester, K.C.B., F.R.S. Pp. xiii + 

 412. (London : .-\dlard and Son, 1912.) Price 



6,T. <)(/. lift. 



SiK Rav Lankester 's weekly contributions to 

 TIte Daily Telegraph represent the high-water 

 mark of popular papers on scientific subjects. 

 The general public has in recent years been infected 

 with a feverish desire for sensation ; and as 

 science can offer little to gratif}' that appetite, 

 thoughtful articles upon its achievements are now 

 relatively much fewer in the periodical Press than 

 they were a generation or two ago. Possibly 

 men of science are partly to blame for this state 

 of affairs. They must be specialists in order to 

 make progress in their own particular fields of 

 inquiry ; and they are often not only themselves 



