March 31, 19 10] 



NATURE 



^IZ 



w ith a proposal to form a company to construct a full- 

 sized machine from the author's plans. The principles 

 on which the author relies are not those generally 

 accepted. He maintains that the centre of pressure 

 for a plane does not vary- with its inclination to the 

 line of flight, that the normal pressure is independent 

 of the inclination, and that flapping wings can be 

 constructed so as to be mechanically more efficient 

 than a screw propeller. To establish these principles 

 he seems to rely on rough experiments with kites and 



Fig. 2. — Armoured Delence against Airships, From "'Aerial Navigation of To-day, 



:mall gliders. The accuracy of the observations and 

 he deductions made from them both seem open to 

 juestion. Plotting v against i, the g^aph of 



M Va 



s said to be a straight line, because v and i only 

 ippear in the first power. The author maintains that 

 lis observations prove Langley's to be inaccurate, and 

 ittempts to explain away the discrepancy between his 

 )rinciples and Langley's experiments in a way which 

 s not convincing. 



(3) The preface to Mr. Lawrence Rotch's book is 

 lated April, 1909, and when we think of the number 

 if flights performed since then it will be evident that 

 NO. 2109, VOL. 83] 



no writer could possibly bring out a book containing 

 the most up-to-date records in aviation. The author 

 has, on the other hand, brought into prominence 

 several aspects of aerial navigation which are apt to 

 be forgotten in these days, when the breaking of 

 records by 'planes (not to mention other breakages of 

 a regrettable character) is the all-absorbing topic. 

 For example, in chapter i., the ocean of air, we have 

 an account of the results of meteorological obser\-a- 

 tions in which the author has played a most 

 important part. It is illustrated by dia- 

 grams showing the greatest altitudes 

 reached by mountains, balloons, and 

 ballons sondes, also variations of tem- 

 perature and wind velocity with the 

 altitude, and it well shows up the effi- 

 ciency of kites and ballons sondes in 

 exploring regions of the atmosphere to 

 which man can never hope to penetrate. 

 In the second chapter — the history of 

 aerostation — the author reproduces the 

 letters of Benjamin Franklin to Sir 

 Joseph Banks, P.R.S., describing the 

 first balloon ascents made in France. 

 The following extract from one of these 

 letters is worth reading at the present 

 day : — 



" I am sorn,' this Experiment is 

 totally neglected in England, where 

 mechanical Genius is so strong. I wish 

 I could see the same Emulation between 

 the two nations as I see between the 

 two Parties here. Your Philosophy 

 seems to be too bashful. In this country 

 we are not so much afraid of being 

 laught at. If we do a foolish thing we 

 are the first to laugh at it ourselves, and 

 are almost as much pleased with a Bon 

 Mot or Chanson, that ridicules well the 

 Disappointment of a Project, as we 

 might have been with its Success. It 

 does not seem to me a good reason to 

 decline prosecuting a new Experiment 

 which apparently increases the power of 

 Man over Matter, till we can see to 

 what Use that Power may be applied. 

 When we have learnt to manage it, we 

 maj' hope some time or other to find 

 Uses for it, as men have done for Mag- 

 netism and Electricity, of which the first 

 Experiments were mere Matters of 

 Amusement." 



How true this all sounds to-day! In 

 England there does not, we believe, 

 exist at the present time a single prize 

 for any scientific investigation bearing 

 on aerial navigation. Had such a prize 

 existed the theory of longitudinal and 

 lateral stability could have been disposed of years 

 ago, and aeroplanes could have been built with a 

 clear understanding of their stability or lack of it. 

 It should surely have been worth while also for those 

 who spend such large sums on construction of 

 dirigibles to take some steps to obtain a theor}' of their 

 stabilit}-, but this has not been done. There are 

 several other problems, including one or two in dis- 

 continuous motion, awaiting solution ; and it is not the 

 mathematician alone who is handicapped by the per- 

 sistent refusal of English people to provide any ade- 

 quate recognition of original work. 



We should be greatly surprised if members of the 

 engineering profession would not be glad to make 

 use of a similar encouragement to carry out experi- 

 ments of rather a more scientific character than would 



