Chemistry and Physics. 483 



and satisfactory. Our opinion of the book may be best expressed 

 by the statement that we shall use it in one of our intermediate 

 courses during the coming winter. H. s. tj. 



] 0. A Text-Book of Physics, Third Edition ; edited by A. W. 

 Duff. Pp. xvi, 686 ; 595 figures and 284 problems. Philadel- 

 phia, 1912 (P. Blakiston's Son & Co.). — A careful comparison of 

 the latest edition of this work with the second (see vol. xxviii, 

 page 556) brought out the following facts. The chapter on heat, 

 which was formerly composed by Guthe, has been entirely 

 rewritten by Mendenhall. In the subjects of electricity and mag- 

 netism Goodspeed has surrendered his pen to Carman. The 

 articles on sound and mechanics have not suffered much alteration. 

 Lewis has decreased the number of pages devoted to light from 

 140 to 118, while McClung has brought the numerical data in the 

 conduction of electricity through gases and in radio-activity up 

 to date. The sequence of subjects has been changed to the 

 following order : (1) mechanics, (2) wave-motion, (3) heat, (4) 

 electricity and magnetism, (5) gaseous conduction and radio- 

 activity, (6) sound, and (7) light. Some of the figures have 

 been replaced by new and clearer diagrams, they all appear to 

 have been relettered, and the total number of figures has been 

 increased by seventy. Four-place tables of the common loga- 

 rithms of numbers and a table of natural sines and cosines have 

 been introduced immediately before the first index. Great care 

 seems to have been taken to avoid the old typographical errors 

 and to give the text a more polished and elegant appearance. 



h. s. u. 



11. Gravitation; by Frank Harris. Pp. xi, 107 ; 18 figures. 

 London, 1912 (Longmans, Green & Co.). — Less than six full 

 lines are devoted to the preface, which amounts to the confession 

 that the volume may not be "entirely free from clerical errors" 

 and may "involve erroneous deductions." Furthermore, the intro- 

 duction deals only with the question of the meaning to be 

 attached to the word " explanation," when dealing with natural 

 phenomena. Hence, the author gives no explicit clue to the 

 object which he had in writing the book or to the gap which the 

 text is intended to fill in the literature of the subject. The text 

 is highly mathematical and the figures are graphs of certain 

 functions. The titles of the chapters are : — I Medium, Particle 

 and Motion ; II Spheres in Sequence ; III Potential Energy ; 

 IV Sources and Sinks ; V Two Circles ; VI Spheres in Parallel ; 

 and VII The Dimensions of Space. The volume closes with a 

 chapter on "Atomic Forces," which is presented as an appendix. 

 On page 29 the author uses the term " veetal " to signify "the 

 loss of potential energy in an attracted particle due to its transfer 

 from infinity to a given point." h. s. u. 



