Chemistry and Physics. 85 



does not introduce an appreciable error. He finds that Poisson's 

 equation is applicable to electric discharges through a gas. — Ann. 

 der Physik, No. 13, 1908, pp. 571-588. " J. t. 



10. The Elements of Physics ; Vol. II, Electricity and Magnet- 

 ism ; by E. L. Nichols and W. S. Franklin. New edition, pp. 

 vii + 303, with 196 figures. New York, 1907 (The Macmillan 

 Co.). — This edition of the second volume of Nichols' and Franklin's 

 Elements of Physics has been entirely rewritten. No statement 

 is made here, however, concerning a new edition of the other 

 volumes, nor have we seen any announcement elsewhere. 



The most salient feature of the new edition is the discarding 

 of the traditional treatment of electrostatics, beginning with elec- 

 trostatic attraction and the definition of the electrostatic unit of 

 charge. The authors say: "It seems better to approach this sub- 

 ject from the standpoint of the ballistic galvanometer, inasmuch 

 as, when so developed, the theory of electrostatics is a logical con- 

 tinuation of the foregoing theory of the electric current." "Most 

 students begin electrical theory at both ends and never reach the 

 middle." 



The columns of mechanical and electrical analogies at the end 

 of Chapter VII and at the beginning of Chapter XVI are inter- 

 esting and complete. At the close of the book a list of 145 well- 

 selected problems is given. The volume as a whole is attrac- 

 tively executed and reflects credit both on the authors and on the 

 publishers. h. s. it. 



11.-4 Text-Book of Physics ; edited by A. W. Duff. Pp. xi + 

 680, with 511 figures and 225 problems. Philadelphia, 1908 (P. 

 Blakiston's Son & Co.). — This volume is a new departure in the 

 writing of college text-books, in that seven experienced teachers 

 have contributed to its production. The various divisions of the 

 subject and the authors responsible for them are as follows : 

 Mechanics, pp. 1-177, written by A. W. Duff; Heat, pp. 179-281, 

 by K. E. Guthe; Wave Motion and Sound, pp. 283-328, by W. 

 Hallock; Light, pp. 329-474, by E. P. Lewis; Electricity and 

 Magnetism, pp. 475-630, by A. W. Goodspeed ; Conduction of 

 Electricitv through Gases and Radio-Activity, pp. 631-666, by 

 R. K. McClung. 



An obvious danger attendant upon each contributor writing 

 about his special field is that of his treating the subject at such 

 length as to weaken in the student's mind the contrast between 

 the fundamental facts and those of less significance. In other 

 words, too much detail tends towards a dead level of the special 

 branch under discussion. This danger does not seem to have 

 been successfully avoided, in spite of the fact that the sections 

 written by each author were freely criticized by his six collabor- 

 ators. This objection is especially pertinent to the chapters on 

 Light. In the preface the suggestions are made: "Some may 

 find the material included in the book too extensive for a single 

 course. If so, a briefer course can be arranged by omitting all 

 of the parts in small print together with as much of those 



