Page:Popular Science Monthly Volume 89.djvu/595

 Popular Science Monthly

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��undergone several simple cx;uninations, the candidale is seated in a chair and the fnial, supreme test is ajiplied.

How would most men act if a revolver were discharged unexpected!)' behind their ears? The answer is simiiie. The\' would leap into the air; their heart-beat would probably double; the\' would gasp and tremble as if they had palsy. In so doing they would promptly disqualify themselves as aviators in the French army.

In testing the possibilities of an avia- tor, various contrivances are attached to the body, all having a definite purpose.

���Tubes lead from these devices to a slowly rotating cylinder, on which i)aper is wrappeil. They terminate in points which record the slightest variations in his [)h>sir|ue.

When the clockwork has started and he is perhaps wondering what the queer apparatus is all about, a deafening ex- plosion takes place a foot behind him. The record made at that moment on the revolving paper determines whether or not he is to become a French war-aviator. If his heart-beat, his respiration and his arm nerv^es and muscles show no undue excitement on the paper cylinder, he goes to work. But if the stylus actuated by his pulse -beat dances about the rotating sheet, he is disqualified. It is only natural that his reflex nervous system should respond in some way to this sudden stimulus; but the man who tests him knows how wide a variation from normal may be tolerated.

Next in importance to the revolver- shot test is that which ascertains the candidate's promptness in acting upon an external command. For example, he is told to press an electric button when he feels a light touch on his left ear- lobe, or when he sees a light flash. His ciuickness in acting upon these sensations determines whether or not he could meet the sudden contingencies which occur in the air. In a word, whether or not he could handle his 'plane over a roar- ing battlefield with- out losing any part of his nerve.

��The d'Arsonval chronormtt i. im h records on a smoked paper cylinder the pulse-beats, respiration and nervous tremors of the applicant when a pistol is fired behind him

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