September 8, 192 1] 



NATURE 



Z7 



The programme the author sets himself is very 

 suitable, there being chapters on the theory of 

 flight, aeroplane construction, rigging, propellers 

 and maintenance, while an appendix professes to 

 deal with aerodynamical formulae and calculations. 

 The general descriptions are passable, and evi- 

 dently the author has had practical experience, but 

 I the theoretical side of the book is lamentable, and 

 renders the whole work quite unfit to be called a 

 "text-book." 



The account of stability makes one wonder 

 whether there should not be some censorship over 

 scientific publications. Thus the author decrees, 

 without any reference to the shape of a body, that 

 " in this state (viz. of neutral equilibrium) the 

 center of gravity of the body is at its center." 

 He declares the best form of equilibrium to be the 

 neutral state. Apparently, stability is the next 

 best thing. On propellers the author announces : 

 "Propellers and mystery are synonymous. In our 

 Year of Grace 1919, nobody knows exactly what 

 a propeller is " ; yet seventeen pages follow to 

 elucidate this mystery. One is pleased to be able 

 to say that the chapter on " flight hints " is quite 

 interesting. 



"Aerodynamical formulae and calculations," in 

 the form of an appendix, consists of a lecture 

 delivered so far back as 191 1. After the sort of 

 sneers at mathematicians usual with a certain class 

 of people who do not understand mathematics, the 

 author gives some hopelessly inadequate formulae 

 which might have passed muster in the dark 

 middle ages of aviation, but are certainly unfit as 

 a statement of post-war knowledge. The climax 

 of the book is reached, however, in the "defini- 

 tions." Algebra is "defined," and a treatise on 

 algebra follows which occupies four pages ! The 

 metric system is described as resting on a "natural 

 and invariable standard," the metre being given 

 as 30-37 in., and the litre as 10567 quarts. 

 Momentum is defined as the "force of motion 

 acquired by a moving body by reason uf the con- 

 tinuance of its motion." Trigonometry is "de- 

 fined," and then follows a treatise on trigono- 

 metry, complete with tables, in three pages ! One 

 can only regret that the author did not make sure 

 about his mathematics and mechanics before he 

 wrote the book. 



(2) Messrs. i\ndrew and Benson's contribution 

 to the " Directly-Useful " technical series of books 

 issued by Messrs.. Chapman and Hall deals with 

 aeroplane design, largely from the aerodynamical 

 point of view, but also from the structural. After 

 two general chapters on the fundamental principles 

 of aeroplane design and on the materials available 

 for the purpose, the authors give a detailed 

 NO. 2706, VOL. I08I 



account of the properties of aerofoils, with carer 

 fully compiled data in tabular and graphical fohn^ 

 of the kind made familiar by the publications, of 

 the aeronautics department of the Natiooal 

 Physical Laboratory. This is followed by the 

 theor>' of stresses and strains in struts and rods 

 which is applied to wing-structures for mono- 

 planes, biplanes, etc., in some detail, with a 

 number of numerical illustrations. The aero- 

 dynamics of stream-line bodies and struts comes 

 next, followed by chapters on the design of the 

 fuselage and chassis, both aerodynamically and 

 structurally. There is a good chapter on the 

 design of airscrews, including a brief account of 

 the stresses on an airscrew. As introductory to 

 the design of control surfaces, the authors give 

 the usual kind of treatment of the theory of sta- 

 bility, with an account of the different resistance 

 derivatives and numerical applications to various 

 kinds of machines. The chapter on performance 

 includes the instruments used in machines, and 

 this is followed by two interesting chapters on the 

 general lay-out of machines and on the trend of 

 aeroplane design. 



The book is clear, accurate, and profusely illus- 

 trated by more than 300 excellent plates and dia- 

 grams. While not differing widely in matter and 

 arrangement from other books already published, 

 Messrs. Andrew and Benson's book, which is quite 

 elementary in places, can be safely recommended 

 as an easy and not too mathematical statement of 

 our knowledge of the aeroplane in so far as this 

 knowledge bears on the problem of design. 



(3) Messrs. Pippard and Pritchard have pro- 

 duced a thoroughly trustworthy treatise, based to 

 a large extent on their personal " experience during 

 the war while engaged in the work of supervising 

 experimental designs from the standpoint of 

 structural strength." The book is not merely a 

 statement of results ; it contains a competent 

 treatment of the subject from the theoretical point 

 of view, and the student is not left wondering 

 how results quoted are to be justified mathematic- 

 ally and mechanically, a fault that mars so many 

 of the books on aeronautics. 



After a statement of the nature of the problem 

 dealt with in the book, the authors give a brief 

 account of the mechanics of flight and then pro- 

 ceed to a description of the structure of an aero- 

 plane in general and in detail. Chapters follow 

 on the evolutions of an aeroplane in flight, with 

 the consequent loads that the various parts have 

 to carry during and immediately after such evolu- 

 tions. The subject having been thus introduced, 

 the authors then deal with the elementarv theory 

 of elasticity, framed structures from the graphical 



