352 Scientific Intelligence. 



that the 'uninstructed reader would react more placidly to 

 * Apellate" and ''tractate" than he would to ''repel" and 

 "attract." However the tenderness of the author to the read- 

 er's prejudices is happily shown by the inclusion, at the end, of a 

 glossary of most of the terms which connote scientific ideas or 

 exact definitions. 



Coming to the contents of the book the success of the author's 

 presentation is most commendable. The four chapters devoted 

 to atomic structure give an excellent idea of how the modern 

 theories account for both chemically active and inert atoms, the 

 periodic system, and atomic weights. The discussion passes then 

 to radioactive disintegration, conduction of electricity through 

 gases, conduction through solids and liquids, electromagnetic 

 induction and electrodynamics. A chapter for each is devoted 

 to the proof for the existence of the electron, to the isolation of 

 the proton, and to X-rays and atomic numbers. 



The author now introduces a jeii d' esprit in the form of a dia- 

 logue between the dramatis personae of the book, to wit, the 

 proton, the electron, the author, the scientific reader, the general 

 reader, and the voice of energy, the purpose of which appears to 

 be to prepare the peruser of the book for a serious discussion of 

 further phenomena. The next chapter is given to photoelec- 

 tricity, then one to light radiation, one to the quantum hypothesis 

 and the last to energy and its availability. An illuminating dis- 

 cussion of the numerical magnitudes of electrons and some other 

 quantities is reserved for an appendix. 



The author's style is clear and the material highly informing. 

 Indeed one can hardly read the book through without being pro- 

 foundly impressed by the things that have been revealed in our 

 microcosmic world during the past twenty years. It is a book 

 that may be commended to the attention of anyone who reads 

 this notice. f. e. b. 



9. Mathematics for Students of Agriculture; by Samuel 

 Eugene Rasor. Pp. VIII, 290. New York, 1921 (The Macmil- 

 lan Company). — The present volume is a reflection of the fact 

 that students choosing agricultural • courses in technical schools 

 and colleges have not had sufficient or proper preparation in 

 mathematics for successful completion of their work. The book 

 may be described as an abridged hand book treating of drawing, 

 arithmetic, algebra, geometry, trigonometry, surveying, and sim- 

 ple machines, with the materials so selected that they may func- 

 tion with the student's special interest and point of view. The 

 various topics are illustrated by special examples and a great 

 supply of problems for the student's exercise. The book should 

 prove of value to teachers in agricultural colleges and also to 

 students who have but limited opportunity for mathematical 

 instruction. p. e. b. 



