500 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1940 



speed barrier is a fortunate thing, for that suggests some finality to 

 the development of types, and limits, moreover, any uncomfortable 

 rivalry with the speed of response of the human body. It is for- 

 tunate, too, that this speed limit is much above the economic limit 

 for civil machines, for that means that the civil type can easily be 

 defeated if it tries to play the corsair. And it most blessedly hap- 

 pens at the same time that the strength of antiaircraft defense from 

 the ground and in the air is increasing in effectiveness at a rate that 

 even the optimistic had hardly hoped. Britain, a fortress in the sea, 

 must become a fortress in the air I 



In my view there will be no reason, once the international situa- 

 tion has cleared, why there should not be an agreed limitation in 

 respect of numbers of tonnage of bombing aircraft — leaving the 

 interceptor fighters entirely aside. It would be but cautious to 

 agree on a limit to the speed of civil types, but as this would merely 

 confirm what economic requirements would themselves suggest, it 

 need be no hardship; excessively high speeds for civil types do not 

 pay, are much more dangerous to passengers, are much more noisy to 

 everyone, and need wasteful forms of airports. 



When this difficulty of our own age has been at last happily solved, 

 we may be very content to leave our successors the even more threat- 

 ening menace of dealing aright with the problem of atomic energy. 

 This it is not necessary for me to describe. I will only say that in a 

 recent broadcast address Professor Cockroft spoke of an atomic trig- 

 ger action between the metal uranium and a single neutron which is 

 reported to be capable of releasing a 100,000,000-fold increase in. 

 energy. Perhaps there are immense practical diflBculties in doing 

 this on a large scale; I earnestly hope there are. For ourselves we 

 are quite sufficiently occupied with our own problem, how rightly to 

 guide the future of flying. 



