466 reille: anti-aircraft firing 



sides, the aircraft war was considered as a supplementary duty 

 for the field materiel and this duty had to be fulfilled by whatever 

 means could be improvised (burying the trail of the gun, etc.). 



In proportion as the war developed, the invention and exten- 

 sion of a special anti-aircraft materiel have taken on greater 

 and greater importance in the armies of thte Allies as well as in 

 the German army, and this in proportion to the importance 

 taken by the means employed for aerial observation. 



The object of this lecture is not to study the improvements 

 made in anti-aircraft materiel but to follow in its different 

 stages and up to the point where it is, today, the study of the 

 general problems which anti-aircraft war has presented to the 

 minds of artillerymen. 



As long as the objectives of artillery were terrestrial targets 

 the interest in the study of the trajectory seemed to be Umited: 



(a) To the initial part of the ascending branch (angle of ele- 

 vation, angle of jump, angle of projection oj: departure, clearing 

 angle, etc., etc.). The study of the initial part of the ascending 

 branch was entirely oriented in the double problem of defilade 

 and range. 



(6) To the terminal part of the descending branch (angle of 

 fall, angle of impact, angle of protection, angle of ricochet; the 

 apparent elevation of the burst, etc.). The study of the ter- 

 minal part of the descending branch was entirely oriented in the 

 problem of the vulnerability of the target according to its nature 

 or its location. 



When it was a question of firing at aerial targets the tendency 

 at first was, and this is easily comprehensible, to argue in regard 

 to these targets as if they were merely terrestrial targets raised 

 to a very high angle of sight. One of the first results of this 

 theory was to erroneously apply to these targets: first, the idea 

 of a normal height of burst (hauteur type) above the target that 

 would give the maximum effect; second, the hypothesis of the 

 rigidity of the trajectory. 



