96 CONTEMPORARY SCIENCE 



again a condition which corresponds quite closely to the 

 tactical advantage of maneuvering between the wind and 

 the enemy. In this case it is not a direction in the plane 

 of the horizon, except so far as light is important ; but it 

 is the direction at right angles, vertical to this plane. It 

 is the upper position the advantage obtained by him who 

 can climb above his enemy, and, choosing the moment 

 of attack, can swoop down upon him from above. 



With this as one of the fundamental conditions of 

 aerial warfare, it was inevitable that in the development 

 of the battle plane there should be the utmost effort to 

 produce machines of continually greater speed and, its 

 correlative, climbing power. Likewise in the air, the 

 greatest practicable altitude has meant for the flying man 

 at once an advantage over his enemy and a reduction of 

 his own chance of being hit by anti-aircraft fire from the 

 enemy's guns on the ground. 



Accordingly, from the comparatively low altitude at 

 which the aerial fighting of the first year of the war 

 usually occurred, the struggle rose, as more and more 

 powerful airplanes were constructed by both sides, until 

 at the end of the war it was quite common for battle 

 planes to ascend to altitudes of 15,000 to 18,000 feet 

 three miles up, higher than the summits of the Rocky 

 Mountains or the Alps. 



Along with this development there occurred with in- 

 creasing frequency among the aviators a condition of so- 

 called "air-staleness." It is a condition closely similar to, 

 perhaps identical with, the "over-training" or staleness, 

 the physical and nervous impairment of athletes in a foot- 

 ball team or college crew. In the last year of the war this 

 condition had become so common that, as reported to us 

 by some observers, the majority of the more experienced 

 aviators in the British service were incapacitated to as- 

 cend to the necessary altitude, and many could no longer 

 fly at all. It was to make good this most serious military 

 deficiency that the enlistment and training of aviators 



