AlGisT -iS, 1903.] 



SCIENCE. 



273 



|)resentation in the lecture room rather than 

 the laboratory. The student is assumed to 

 have alroad.v completed a good high-school 

 course, and the aim is not so much to acquaint 

 him with interesting phenomena as to put 

 him in touch with the methods and means of 

 physical investigation. Wliether the book can 

 be protitably used by teachers of physics gen- 

 erally, by putting it into the hands of their 

 students, it is not possible to make any positive 

 assertion; but it can not fail to be very sug- 

 gestive and otherwise useful to all whose 

 range of duty coincides even in part with that 

 of the author. 



Professor Sanford's book is like that of Dr. 

 Millikan in one important particular, that 

 it is intended jointly as a presentation of 

 theory and a laboratory guide. He believes 

 the lecture-room method of imparting knowl- 

 edge to be the poorest of all methods with ele- 

 mentary students, and his book has been writ- 

 ten with the idea that it will not need sup- 

 plementing by a lecture course. " It has 

 been prepared especially for the teacher who 

 has had an adequate training in the physical 

 laboratory, and it is not likely to succeed 

 with any other teacher." It is issued more 

 especially for California students of high- 

 school grade who compose a majority of the 

 applicants for admission to the Stanford Uni- 

 versity; but it is evidently best suited for that 

 increasing proportion of high schools in 

 which the work encroaches largely on that 

 of the college, and which seem destined within 

 the next generation to supplant the small col- 

 lege in all except the thinly populated parts 

 of our country. The author lays much stress 

 on the importance of following in the labo- 

 ratory the general method of scientific dis- 

 covery, in which the acquisition of individual 

 facts; must precede generalization, while this 

 in turn is followed by deduction and such 

 si)ecial experimentation as is necessary to 

 test its validity. Among the salient features 

 of the book are the attempt to base the in- 

 itial development of mechanics consistently 

 upon the concept of energy, the discussion of 

 the gaseous state of matter as a preliminary 

 to that of the liquid and solid states, and in 

 optics the complete elimination of 'the fiction 



of rectilinear propagation.' This last is a 

 self-imposed and quite unnecessary limitation. 

 If we admit the wave theory and the existence 

 of wave fronts in a medium with known prop- 

 erties, the direction of propagation becomes 

 as recognizable as the wave front, and it can 

 scarcely be called a fiction unless the medium 

 is also fictitious. The luminiferous ether may 

 perhaps be still called a fiction, though one 

 of great convenience and an intellectual neces- 

 sity at present. Whether the wave front 

 method or the ray method of explaining 

 optical phenomena be preferred is a matter 

 of convenience or of fashion. There can be 

 no inconsistency in using both or either at 

 will, and certainly each has its own advan- 

 tages. 



The volume by Messrs. Andrews and How- 

 land presents no such departures from pre- 

 vailing usage as the two just noticed. It is 

 well balanced, well arranged and clear in style, 

 but it contains no features that have not 

 been exemplified in some of the better ele- 

 mentary class text-books in common use. The 

 general plan of the authors has been to elimi- 

 nate subjects that are of mere theoretic in- 

 terest and to emphasize those that are prac- 

 tical; to use the simplest language possible 

 and to avoid mathematical formulas in all 

 eases where these are not absolutely necessary ; 

 to show as much as possible, for every subject 

 selected, its relation to fundamental principles 

 or their obvious corollaries. 



Gage's ' Introduction to Physical Science ' 

 is a revised edition of a book that has been 

 on the market since 1887. The author was 

 at that time the well-known champion of the 

 idea, at present advocated anew by Professor 

 Sanford, that the student must be an in- 

 ductive investigator. Mr. Gage now fully 

 recognizes ' the consensus of opinion among 

 teachers of physics that the method of instruc- 

 tion which includes a due proportion of text- 

 book study, lecture-room demonstration and 

 individual work in the laboratory is the 

 method conducive to the highest order of 

 results from an educational point of view.' 

 The present volume is essentially a class text- 

 book, and not a laboratory manual or a 

 reading book for parallel private study. It is 



