242 



NATURE 



[May 30, 19 1 8 



cation and the mainspring of creative life. At 

 any rate, it is that which the people themselves 

 are asking for, but it is the principle which at 

 the moment is threatened with submersion. 



Pure and applied science, the author insists, 

 should not be divorced in the schools, and he has 

 some warnings to give science teachers of the 

 danger of "science laboratory courses," where 

 experiments are mainly .designed to verify a law, 

 to demonstrate a fact, to determine the value of 

 a physical constant, or merely to measure some- 

 thing. He is all for allowing theories to wait on 

 practical investigations, and most teachers will 

 now agree. 



Two criticisms may be offered. The author, 

 with all his belief in the application of' science, 

 does not go the whole way and advocate boldly 

 the teaching of applied science in the school. He 

 would find that such a science course would lead 

 in the early stages at school to the elementary 

 (so-called) scientific theories and to mathematical 

 developments. He seems still content to "illus- 

 trate " theory by "practical applications " — which, 

 we submit, is illogical and derogatory. However, 

 the method of illustration is dominant to-day — 

 except where needs must, some science may be 

 taught with a vocational "bias," which seems un- 

 natural, crooked, and non-creative. 



Even more serious is the author's silence on 

 what is, after all, the most vital thing in scientific 

 education — the growth and development of the 

 "science outlook " on life — the gospel of science.. 



AVIATION ENGINES. 

 Aviation Engines: Design, Construction, Opera- 

 tion, and Repair. By ist Lieut. V. W. Pag^, 

 Pp. 589. (London : Crosby Lockwood and 

 Son, 1918.) Price 155. net. 

 'T'HE author expresses the desire in his preface 

 -*- that this book shall prove of use to men in 

 the aviation section of the U.S. Signal Corps and 

 to students who wish to become aviators or avia- 

 tion mechanicians. The subject is obviously one 

 beset with difficulties and restrictions at the pre- 

 sent time; not only is practice changing with 

 bewildering rapidity, but much of the information 

 which it would be most useful to impart it is now 

 impossible to print in any book purchasable by the 

 public. These limitations must in fairness be 

 borne in mind when a book on this subject is re- 

 viewed, but there are sections of it to which such 

 considerations do not apply, and which can pro- 

 perly be judged on their merits— as it happens, it 

 is in these sections that the main defects of the 

 book are found to lie. 



Lieut. Page sets out to provide "a complete 

 practical treatise outlining clearly the elements" 

 of the subject, together with sections on the 

 design, construction, operation,* and repair of 

 aviation engines. We do not think, however, 

 that the elements have been either clearly or accu- 

 rately outlined; on p. 21 work is measured on a 

 time basis, and is identified with power ; again, 

 on p. 25, hiomentum is identified with torque, and 

 oh the same page pressure, force, and power are 

 NO. 2535, VOL. lOl] 



all treated as interchangeable terms. Such 

 confusion must spell disaster to any student desir- 

 ing to acquire a right knowledge of "the ele- 

 ments," and it is scarcely too much to say that 

 the theoretical section of the book would be best 

 omitted by those who approach the subject for the 

 first' time. 



The practical part of the book is very much 

 more satisfactory, but overweighted with such 

 irrelevant details as the use and care of files, the 

 use and care of taps and dies, and a section on 

 micrometer calipers and their use. Such details as 

 these are better confined to books on workshop 

 processes, as they are common to all engineering 

 construction. The author has, we notice from 

 certain advertisements included in the volume, 

 already written books — altogether some four or 

 five thousand pages — on such subjects as the 

 modern gasolene automobile ; the location of 

 Ford engine troubles made easy ; motor- 

 cycles, their construction, management, and 

 repair; and like works, and must^ we should 

 have thought, have noticed the impossibility 

 of combining reasonable bulk with inclusion 

 of workshop processes. This condition of 

 practical repletion extends als^ to the dis- 

 cussion, on p. 201, of "why lubrication is neces- 

 sary," since we find that "proper lubricity of all 

 parts of the mechanism is a very essential factor, 

 upon which the durability and successful opera- 

 tion of the motor-car power plant depends." As 

 this applies equally to the aviation engine (about 

 which the book is written), it is not understood 

 why a reference to the motor-car is required ; if 

 this sentence, and certain of its successors, are 

 taken from some book on car engines, it would 

 have been better to edit them in the process. 



The book is of interest — and of use — to those 

 who are experienced enough not to be misled by 

 the inexact theory, and can select- what is 

 useful from what is not ; but as a book for stu- 

 dents or young airmen of any sort we much prefer 

 the "Aero-Engines" of Mr. Burls, which is so 

 much in use in our own Flying Service. 



H. E. W. 



OUR BOOKSHELF. 



A Check List of North American Amphibians and 

 Reptiles. By L. Stejneger and T. Barbour. Pp. 

 iv+125.. (Cambridge, Mass. : Harvard Univer- 

 sity Press, 1917.) Price 105. 6d. net. 

 This is the third list of the kind issued in America, 

 the earlier being by Cope (1875) ^"d by Yarrow 

 (1882). In the meantime, two monographs have 

 been published by the Smithsonian Institution, viz. 

 Cope's "North American Batrachia " (1889) and J 

 the same author's " Crocodiliahs, Lizards, and % 

 Snakes of North America" (1900), which, as Dr. ' 

 Barbour observes in the Introduction, "are fre- 

 quently erratic and inaccurate." There was great 

 need of a fresh stock-taking of this rich herpetologi- 

 cal fauna, so many striking forms having been added 

 since the publication of Cope's monographs, such 

 as, for instance, Typhlomolge rathbuni (Texas), 

 Ranodon olympicus (^^^ashington), Batrachoseps 



