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SCIENCE 



[N. S. Vol. XXXVI. No. 925 



the blood pressure, the simple action of atro- 

 pin on the heart, and final asphyxia. One 

 •can not examine the book without recalling 

 Mr. Abraham Flexner's discussion of physio- 

 logical instruction in Germany in his valuable 

 report to the Carnegie Foundation on medical 

 ■education in Europe. He says: 



The practical course in Germany is a thing by 

 itself, and is still unsatisfactorily carried on. . . . 

 Consisting as it does of certain exercises specified 

 and minutely described in a syllabus, the practical 

 course tends to be an isolated series of experiments 

 mechanically executed rather than a stimulating 

 and successful application of scientific method to 

 physiological problems. ... If, then, physiology is 

 to be taught as an experimental science, as a sci- 

 'enee of function, the student must be allowed to 

 run risks, to calculate, to observe, to verify, to 

 conclude. Eliminate risk and the experiment be- 

 comes a mechanical toy: it may amuse, it does not 

 'discipline. 



Frederic S. Lee 



Columbia Univeksity 



•Short Course in Electrical Testing. By More- 

 croft and Hehre. New York, D. Van Nos- 

 trand Company. 1911. Pp. 154. Price, 

 $1.50 net. 



This book is designed primarily for the use 

 of students of other branches of engineering 

 •than electrical engineering. As such students 

 are usually none too well versed in the theory 

 of electrical engineering, due to the short time 

 available for the study of this subject, the 

 authors have included with the description 

 of the experiments a brief statement of the 

 more important principles involved. This 

 feature should appeal to any teacher giving 

 laboratory instruction in electrical engineer- 

 ing to students of another department. 



The direct current experiments described 

 deal with the measurements of the resistance 

 of wires, of lamps and of the dynamos; the 

 ■characteristics of the shunt and of the com- 

 pound generator; the characteristics of the 

 shunt and of the series motor, and the 

 parallel operation of shunt generators and 

 of compound generators. The alternating 

 current experiments deal with determina- 

 tion of wave shape; phase displacement and 



power; the effect of inductance, capacity 

 and frequency; the regulation of an alter- 

 nator; transformer losses; characteristics of 

 the induction and synchronous motors, and 

 of the rotary converter; the parallel operation 

 of alternators, and currents, voltages and 

 power in three-phase circuits. 



At the end of each experiment is given a 

 number of questions concerning the prin- 

 ciples involved and the reasons for the be- 

 havior of the various types of machines. It 

 is to be regretted that the authors have not 

 included in these queries more questions de- 

 signed to bring out the bearing of the various 

 characteristics upon the commercial applica- 

 tion of the machines. Particularly for non- 

 electrical students is it desirable, both for its 

 inherent value and to keep the interest of the 

 students, to bring out repeatedly the uses of 

 the various types of machines and the fea- 

 tures limiting their application. In some of 

 the questions the premises are only partially 

 stated. For example, on page 65, is the fol- 

 lowing : " Explain . . . why a series motor of 

 the same horsepower rating as a shunt motor 

 exerts a greater full load torque." In this 

 connection, it may also be noted that nothing 

 is said as to the difference in the methods of 

 rating shunt and series motors. In fact, the 

 question of rating and temperatures seems to 

 be omitted entirely from the book. 



In the alternating current section there are 

 certain features which are not altogether de- 

 sirable. In the first place the clockwise sys- 

 tem of vector notation is employed. Again, 

 the terms " impedance " and " reactance " 

 seem to be avoided, although frequent men- 

 tion is made of " conservative " and " dissipa- 

 tive " reactions, inductance and capacity reac- 

 tions, etc. It is also to be regretted that the 

 authors have given no index to the book. 



The experiments selected and the directions 

 given are in the main entirely satisfactory. 

 On the whole the book should prove very use- 

 ful for the purpose for which it is primarily 

 intended, i. e., a laboratory manual for non- 

 electrical students. 



Harold Pender 



Massachusetts Institute of Technology 



