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THE POPULAR SCIENCE MONTHLY 



The New Physics. A Manual of Experi- 

 mental Study for High Schools and Pre- 

 paratory Schools for College. By John 

 Trowbridge, Professor of Physics, Har- 

 vard University. New York : D. Apple- 

 ton & Co. Pp. 367. Price, $1.50. 

 We have especial pleasure in calling the 

 attention of science-teachers in our higher 

 grades of schools to this timely and valu- 

 able text-book. Its title, " The New Phys- 

 ics," is appropriate in a double sense, and 

 is, in fact, the true key to the understanding 

 of its character and claims. 



But at the outset let us say that Profess- 

 or Trowbridge's book is not new in the sense 

 of treating of all the latest scientific novel- 

 ties. It is not a digest of information on 

 physical subjects for instructive reading and 

 convenient reference, and makes no account 

 of " the latest things " which it is often 

 thought desirable to get into school-books, 

 to " bring them up to the present time." 



But the work is new, in the first place, 

 as representing a great step of advancement 

 in the fundamental ideas and general view 

 of the subject, which is now properly desig- 

 nated " the new physics." No one discovery 

 in the whole sphere of scientific thought 

 has ever proved to be so profound and far- 

 reaching in its influence as what Dr. Faraday 

 calls *' the highest law in physical science " — 

 the law of the conservation of energy. The 

 older views of the nature and laws of forces 

 — the radical problem in physics — have 

 been left behind us, antiquated by the 

 emergence of the great principle of correla- 

 tion and conservation which gives us a new 

 and grander conception of the method of 

 Nature. Professor Trowbridge has first 

 made this principle basal in the study of 

 elementary physics, and has chosen a title 

 for his book which marks the present ad- 

 vance of the subject, and sharply contrasts 

 his treatment of it with that of the older 

 expositions. 



In the second place, the method of teach- 

 ing adopted is new in the sense that it is a 

 progressive step in total contrast with the 

 old and still prevailing method. This book 

 is a guide to the study of phenomena. The 

 pupil is taken through a systematic course 

 of experiment in the laboratory, doing his 

 own observing, his own manipulating, and 

 his own thinking, and thus making his 

 acquisitions real. The literary method of 



studying science is entirely discarded, with 

 its vague results and all the possibilities of 

 coaching and cram. The pupil goes to work 

 at the threshold, and with the assistance 

 and direction of competent teachers, which 

 it is assumed he will have, he carves his 

 way, and becomes thoroughly grounded in 

 the facts and principles of the subject. 

 " The New Physics " thus conforms to the 

 spirit and embodies the method of " the 

 new education." 



Physics can not be truly taught without 

 a laboratory any more than chemistry; but 

 the apparatus necessary is not very expen- 

 sive. On this point Professor Trowbridge 

 says: 



An elementary laboratory of physics for a school, 

 with experiments properly selected — for it is not 

 necessary to cover the whole ground of experiment- 

 al physics in order to gain a large amount of intel- 

 lectual discipline — need not cost more than a chemi- 

 cal laboratory such as is now provided in many high 

 schools. I have endeavored to describe only simple 

 and inexpensive apparatus. The teacher can readi- 

 ly invent simple contrivances which, in many cases, 

 will be better than those I have recommended. My 

 endeavor has been to point out the way to a more ra- 

 tional method of studying physics. In the Appendix 

 will be found additional directions for constructing 

 simple apparatus. It is not supposed that the stu- 

 dent will perform all the experiments in this treatise 

 during the time that can be devoted to physics in 

 the Becond.ary schools. The choice of experiments 

 by the teacher must necessarily depend upon the 

 apparatus on hand, which can be modified for the 

 purpose of this treatise, and upon the amount of 

 appropriation which can be devoted to cheap appa- 

 ratus. 



It is frequently said that experimenting 

 is more play than work, and that boys like 

 it because it is easy. But this remark is 

 not true of Professor Trowbridge's method 

 of studying physics, in which, with regular 

 manipulation, close thinking is enforced. 

 This object is to secure that kind and meas- 

 ure of mental discipline which the study of 

 physical science is capable of conferring ; 

 and that imphes concentrated mental ex- 

 ercise upon actual laboratory processes, so 

 as to arrive at accurate results. Of course, 

 mathematics, the language of exactness, is 

 indispensable, and is constantly used — arith- 

 metic, algebra, geometry. But the amount 

 of the latter needed to use the work is very 

 moderate. Familiarity with simple equa- 

 tions and an elementary knowledge of square 

 root are required, and, as explained by the 

 author, as much trigonometry as can be got 



