132 



NATURE 



[March 31, 1910 



MODERN AERONAUTICS.' 



(i) "lirlTHIN about three hundred pages Mr. 

 * * Turner gives a popular account of the 

 whole field of aerial navigation, including balloons, 

 airships, and aeroplanes, in his survey. He first 

 gives an account of the history and principles of 

 each branch of the subject. In the chapter on the 

 principles of ballooning the expansion of the gas in 

 a balloon appears to be attributed mainly to the heat- 

 ing by the sun's rays, and only a sentence, by the 

 way, refers to the expansion due to the diminished 

 pressure at an increased height, which, of course, 

 affects the gas in the balloon and the surrounding 

 air equally, and also materially affects the vertical 

 stability of the balloon's equilibrium in the air. The 

 natural variation of the temperature of the air with 

 altitude might also be with advantage discussed more 

 fully. In treating of balloons of the non-rigid type, 

 the action of the baUonet in preventing flabbiness 

 might be made 

 clearer. On p. 

 181, after expos- 

 ing the fallacy of 

 an airship tack- 

 ing, Mr. Turner 

 seems to say that 

 aeroplanes are on 

 a different foot- 

 ing. Of course, 

 the speed of an 

 aeroplane is rela- 

 tive to the air just 

 as an airship's is, 

 and an aeroplane 

 and an airship 

 capable of travel- 

 ling at the same 

 speed are under 

 the same condi- 

 tions as to the 

 directions in 

 which they can 

 travel in a wind. 

 The aeroplane 

 can have the ad- 

 vantage only so 

 far as its speed 

 exceeds the air- 

 ship's. 



The second part 

 of the book deals 

 withvariou? 



problems which have to be solved. Very in- 

 teresting speculations are made about the aerial law 

 of the future, and the landmarks, sign-posts, and 

 alighting stations which will be provided for aviators. 

 In chapters on military and naval aeronautics and 

 strategy and aerial invasion, Mr. Turner discusses 

 questions which interest everyone at present. A very 

 clear account is given of the limitations which make 

 some of the achievements that have been attributed 

 to aerial craft impossible, and others improbable of 

 execution, while at the same time full justice is done 



1 (i) " Aerial Navigation of To-day. A Popular Account of the 

 Evolution of Aeronautics." By C. C. Turner. Pp. 327. (London : 

 Seeley and Co., Ltd., 1910.) Price 5s. net. 



(2) " Flight _ Velocity." By Arnold Samuelson. (English edition of 

 "Fluggeschwindigkeit.") Pp. 56; 5 plates. (Hamburg: Boysen and 

 Masch ; London E. and F. N. Spon, Ltd., 1906.) 



(3) "The Conquest of the Air, or the Advent of- Aerial Navigation." 

 By Prof. A. Lawrence Rotch. Pp. x-fi92 ; 36 illustrations. (New York: 

 Moffat, Yard and Co., igog.) 



(4) " Aerodynamik :• eine Gesamtwerk uber das Fliegen." Von F. W. 

 Lanchester ; iibersetzt von C. und A. Runge. Erster Band. Pp. xiv-r36o. 

 (Leipzig and Berlin : B. G. Teubner, 1909.) Price 12 marks. 



to the great services they can render within their 

 limitations. Mr. Turner's discussion of these impor- 

 tant matters can be recommended as sane and reason- 

 able. Other chapters deal with the possibilities of 

 exploration and long-distance travel in general by the 

 air, and in a chapter headed " Work to be Done " 

 attention is directed, among other things, to the need 

 for increased stability in aeroplanes and for a trust- 

 worthy light motor. 



While those who wish to construct aeroplanes will 

 have to have recourse to fuller and more technical 

 treatises, this book fills a want, and a second edition 

 is already advertised. 



In a couple of places characteristically English 

 remarks are made at the expense of mathematicians 

 and men of science in general. These are the more 

 uncalled for in view of the very hazy notions which 

 the book itself shows up, regarding stability and 

 similar questions, that are capable of exact mathe- 

 matical treatment, as well as experimental tests. The 



Fig. 



-Scouts: old and new. From "Aerial Navigation of i'o-day." 



references to stability alone show a lack of exactness 

 in the use of well-known mathematical and ph3'sical 

 terms. Thus in the glossary at the end we have the 

 following definitions : — 



" Equilibrium. — In flying machines the term is used 

 in the same sense as stability," 



" Horizontal stability is the same as longitudinal " ; 

 while on p. 291 the author says (of dirigibles) : — 



"To maintain horizontal stability — that is, to 

 enable the airship to move forward in a straight line 

 without veering to one side or the other — fixed ver- 

 tical planes at the rear of the frame are used. In 

 addition, there is a fixed vertical plane surface at the 

 rear of the gas-envelope." 



The "useful tables " and "glossary" at the end are 

 good features. 



(2) Mr. Samuelson 's pamphlet, a continuation of a 

 previous publication of the author's, begins with a 

 description and drawings of a model flying machine 

 on the principle of " rowing " flight, and concludes 



NO. 2109, VOL. 83] 



