Popular Science Monthly 



713 



Can He Pilot a Battleplane i 



To find out if his sense of balance is good he is whirled around in a special chair. The object of the whirling is to 

 displace the fluid in the labyrinth of the ear, the fluid that controls your sense of balance and tells you whether you 

 are standing on your feet or your head. The examiners then note how long it takes him to recover poise 



it and to select, by punching through the 

 perforations, anything in the chart which 

 appears red or green, as the case may be. 

 These punches are recorded on a blank 

 beneath the chart, so arranged as to show 



whether or not the selections were correct. 

 The eyes must be in perfect alinement. 

 To determine whether they are or not, 

 their muscle-balance, as it is called, is 

 taken. In other words, they must show 



