560 



SCIENCE 



[N. S. Vol. XXXVI. No. 930 



Even here, the symbol becomes rather cum.- 

 bersome, and this is the simplest case of a 

 double relationship. 



Arthur E. Bostwick 



SCIENTIFIC BOOKS 

 Magnetism and Electricity. By Brooks and 



PoYSER. Longmans, Green and Co. Pp. 



vii + 633 ; 413 illustrations. 



This volume is intended by the authors to 

 replace Poyser's " Advanced Magnetism and 

 Electricity " as the latter book had become 

 out of date owing to the enormous progress 

 made in electrical theory during the last 

 twenty years. The subject-matter is presented 

 in experimental form; practically every point 

 treated theoretically is illustrated by one or 

 more experiments. The method is admirable, 

 especially for a text in physics; as the au- 

 thors state in the preface, it is important that 

 a beginner should learn to recognize that all 

 theory is based upon a groundwork of ex- 

 perimental fact. The book treats all of the 

 subjects usually found in a text on electricity 

 and magnetism and the treatment is very well 

 done in most cases. The authors' emphasis 

 upon the student's comprehension of the sig- 

 nificance of the lines of force of the electric 

 and magnetic field we think well worth while ; 

 the more the student is made to understand 

 Faraday's ideas in regard to the electric and 

 magnetic fields the better prepared he will be 

 to understand the operation of instruments 

 and machines. 



The modern conception of the electric cur- 

 rent as the flow of electrons is used in the 

 book and its use is undoubtedly justified at 

 this time, by the results obtained from the ex- 

 periments of various researchers along this 

 line. A chapter is devoted to the discharge of 

 electricity through gases; in the discussion 

 use is made of the latest theories in regard to 

 this phenomenon. The chapters on Dynamos 

 and Motors and on Alternating Currents are 

 entirely inadequate to be of much service to 

 the student. "We think they should have either 

 been omitted altogether or else treated more 

 comprehensively. Any adequate treatment of 

 dynamos and motors requires a deal of space 



and should not be attempted in such an ele- 

 mentary text. 



A carefully selected list of problems is given 

 at the end of each chapter and it adds much 

 to the value of the book as a text. On the 

 whole we think this text to be as well suited 

 for teaching purposes as any that has recently 

 come to our attention. 



j. h. morecroft 



Columbia Univeesity 



The Life of the Plant. By C. A. Timiriazeff. 

 Translated from the revised and corrected 

 seventh Russian edition by Anna Chereme- 

 TEFF. New York, Longmans, Green, and 

 Co. 1912. Pp. 355 with 80 text-figures. 

 $2.50. 



It is a great pity that this admirable popular 

 presentation of the status of plant physiology 

 might not have appeared in English some 

 twenty-five years ago. Originally published 

 in 1878 and passing through seven editions it 

 can not but strike one familiar with the cur- 

 rent literature as being distinctly behind the 

 times, in spite of the evident effort to incorpo- 

 rate various modern investigations. For the 

 specialist the translation has been too long 

 delayed, and even for the general reader there 

 are many views which should be modified in 

 order to give as accurate as possible a notion 

 of what the plant really does. On the other 

 hand, it must be confessed that Professor 

 TimiriazefE has presented the subject in such 

 an attractive form that its very readableness 

 is a strong point in favor of the book. Few 

 of those who have any interest in botany 

 whatever but that will enjoy reading " The 

 Life of the Plant " and the great number of 

 apt illustrations and demonstrations makes 

 one wish that numerous American audiences 

 might have had the opportunity of listening 

 to such a course of lectures thirty-five years 

 ago. The popular conception of a botanist 

 would certainly be higher. 



The book is neither a text-book nor a 

 special treatise, but a simple account of the 

 more fundamental life processes of the plant 

 told in a way calculated to make them inter- 

 esting if not " popular." For this reason it is 



