272 



SCIENCE. 



[X. S. Vol. XVIll. Xo. 452. 



to economy of time. Everything depends 

 upon the special circumstances to which each 

 author has to adapt himself. Any laboratory 

 teacher will probably be able to extract some- 

 thing iiseful from any laboratory manual if 

 he is alert. Instructions must be well 

 methodized and put into good form, but in no 

 case can they be a complete substitute for 

 the instructions needed in any laboratory 

 other than that in which the given manual 

 was developed. The volumes by Mr. Twiss 

 and Mr. Hortvet are, like the first, good ex- 

 amples of method, aU of them being intended 

 for secondary schools, but containing ma- 

 terial that can be utilized by beginners in 

 college. Their purpose is, as well expressed by 

 Mr. Hortvet, ' to teach pupils to measure ac- 

 curately, to manipulate carefully, to work 

 methodically, to see fully, to reason intel- 

 ligently and to express their observations and 

 results clearly.' It would be an untold bless- 

 ing to all students of science, irrespective of 

 age or specialty, if such ideals were unceas- 

 ingly kept in view and even approximately 

 attained.' 



The small volume by Professor Ferry is 

 the first of a series consisting of four parts, 

 the second of which is now in press. They are 

 intended for students, who have a distinct ob- 

 ject in view, that of preparation for the pro- 

 fession of engineering. They are, like all 

 such books, the outcome of local needs, where 

 a large number of students require simultane- 

 ous attention. The aim is ' to furnish the 

 student with a laboratory manual of physical 

 processes and measurements in which the ex- 

 planation of the theory and the description of 

 the method of manipulation of each experi- 

 ment is so complete as to preclude the neces- 

 sity of consulting either another book or a 

 laboratory instructor.' Doubtless there are 

 many besides the reviewer who have been do- 

 ing just this task for years past. Hundreds 

 of pages of manuscript have been prepared, 

 some of which are discarded every year, while 

 the need of new instructions adapted to chang- 

 ing conditions is periodically presenting itself. 

 Many of the details of ro^^tine may be con- 

 fided to assistants, but the calls upon the 

 laboratory director will cease only when he 



gives up his post. Nevertheless the method 

 is on the whole economical. It saves much 

 repetition; it enables the slow student to 

 study out difficulties with a minimum of per- 

 sonal aid; it tends to make him appreciate the 

 advantage of depending on himself to supple- 

 ment by thought whatever shortcomings may 

 seem to exist on pages prepared for the aver- 

 age student rather than for any single indi- 

 vidual. Professor Ferry has done his work 

 with much skill, showing on every page his 

 decided possession of the teacher's instinct. 

 If he should find, by the time the fourth vol- 

 ume is out of press, that the first volume is 

 much in need of revision, because of expan- 

 sion and other changes in his laboratory, he 

 will at least enjoy the satisfaction of having 

 much good company in patiently performing 

 the labor of Sisyphus and doing it well. 



Dr. Millikan's book is a presentation of 

 part of the work in general physics given to 

 first-year students at the University of 

 Chicago. It presupposes the possession of 

 an abundance of apparatus of fine quality, 

 all of which is thoroughly modern, and much 

 of which has been designed and made initially 

 for the Eyerson laboratory. The book is a 

 combination of laboratory manual with class- 

 room text. There are many teachers, there- 

 fore, to whom, on this account, the present 

 volume will partially fail to commend itself. 

 On such a subject no proerustean rules can 

 be laid down, but each teacher must work out 

 for himself the system of instruction by which 

 he can attain the best results. Dr. Millikan's 

 method is to divide his time nearly equally 

 between class-room and laboratory work; but 

 the former is wholly occupied with the discus- 

 sion of the principles presented in the text 

 and their application to practical problems. 

 No demonstration lectures whatever are given 

 until the last third of the year, when there 

 is offered a discussion of those topics that have 

 been omitted from the preceding courses be- 

 cause what is known about them is largely 

 qualitative rather than quantitative. Such 

 subjects as electrostatics, electric radiation, 

 physiological optics and acoustics, the radia- 

 tion, absorption, polarization and interference 

 of light, are hence deemed suitable for initial 



