AND INDUSTRY 7 



to determine his height, his speed or the 

 direction in which he is moving, to enable 

 him to drop his bomb at the right moment, 

 or to sight his gun on his enemy as the two 

 planes come within range. Cambridge, as 

 represented by Horace Darwin and Keith 

 Lucas, has done yeoman service in these 

 various fields, while in all our many discus- 

 sions on theory we have profited by the 

 great knowledge and the clear thinking of our 

 Chancellor Lord Rayleigh, President of the 

 Advisory Committee for Aeronautics. 



Again, turning to another subject, con- 

 sider the science involved in the manufacture 

 of a big gun and its ammunition, or in the 

 calculation of the trajectory of its projectile. 

 Many gun problems are not new: artillerists 

 have long realised the importance of experiment 

 and calculation, the manufacturer to test his 

 steel and determine the safe stresses to which 



