Chemistry and Physics. 347 



is clear and definite. Text books in science are so often brought 

 out by those who are not masters of the subject of which they 

 treat, that it is particularly pleasing to turn over the pages of this 

 volume, elementary as it is, and to note the scientific development 

 of the subject which is manifest on every page. 



The second volume covers a new field, being intended for ad- 

 vanced students with particular attention to the needs of stu- 

 dents of electricity. It is arranged in four parts, written by 

 different members of the department of physics at Cornell Uni- 

 versity. Part I, the work of G. 8. Moler, H. J. Hotchkiss and 

 C. P. Matthews, is devoted to experiments with direct current 

 apparatus and pertains to electrical engineering rather than to 

 physics. It consists of a systematic course of instruction in 

 dynamo practice and satisfies for the first time the demands of 

 engineering colleges for this line of work. 



Part II. is written by Frederick Bedell and is devoted exclu- 

 sively to experiments with alternating currents, a subject of 

 interest to the physicist as well as the electrical engineer; the 

 treatment is systematic and quite complete considering the new- 

 ness of the subject. Many of these experiments are now pub- 

 lished for the first time and contain methods of alternating cur- 

 rent measurement which have been developed to a large extent 

 by Dr. Bedell. The formulation of experiments in a field devel- 

 oped as rapidly as that of alternating currents, is peculiarly 

 difficult and the work may be open to criticism which can be 

 traced to this source. Part II. is scholarly in treatment and con- 

 tains much that is new. 



Part III. consists of a carefully prepared course in photometry 

 and heat, by C. P. Matthews. The experiments in heat are not 

 new, for this subject has been gone over and over by different 

 writers, but the presentation is good. The experimental work in 

 photometry is new in the sense that it is new to text books, and 

 consists of methods which have been developed during recent 

 years dating back to the exhibition in Philadelphia in 1884. 



Part IV. consists of outlines of advanced work arranged by 

 Dr. Nichols and is based chiefly upon recent researches conducted 

 at Cornell University ; the chapters on light sources and spectro- 

 photometry are especially valuable inasmuch as the writer has 

 devoted so much of his time to experimental research in this 

 direction. In this part are described the most recent researches 

 in the various lines of work taken up, with references to original 

 memoirs. 



The work has been carried through the press by Dr. Bedell. 

 The arrangement of the work is admirable ; the mechanical 

 execution all that could be desired. There is no old material ; 

 the illustrations are new. 



The method of treatment throughout the two volumes is one well 

 suited for the requirements of college and university instruction. 

 In the junior course of the first volume, specific experiments are 

 arranged for the student and the exact requirements for each are 

 given. The early portion of the second volume consists of sep- 



