712 



Jennings' Self-Recording 

 Color Test 



A perforated cardboard ex- 

 hibiting confusion colors is 

 placed before the applicant, one 

 perforation corresponding with 

 each color and shade. Some 

 shade of red or green is placed 

 in front of the applicant and 

 he is asked to name it and to 

 select by punching through the 

 perforations anything in the 

 chart which contains - 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 they were punched correctly 



Testing the Muscle 

 Balance of the Eye 



The muscle balance of the eye 

 must be in perfect alinement. 

 In other words, there must be 

 no latent tendency for the eye 

 to turn up or down or in or out. 

 If there is, the aviator may 

 see double and thus endanger 

 his life at a critical moment 



Popular Science Monthly 



The Effect of the Different 

 Head Positions 



The position thirty degrees 

 forward for purposes of whirling 

 tests, brings the horizontal or 

 external canal of the ear into 

 the plane of the turning. This 

 is the position used for the 

 routine examinations for nys- 

 tagmus and pass-pointing. 

 Nystagmus is the term used to 

 designate the visual disturbance 

 set up by the whirling. It may 

 be described as a rhythmic to 

 and fro motion of the eyes con- 

 sisting of two specific move- 

 ments — a slow movement in one 

 direction, followed immediately 

 by a rapid movement in the 

 opposite direction. This con- 

 dition lasts only so long as the 

 fluid within the canal tested 

 continues to flow artificially. 

 Placing the head ninety degrees 

 forward would have the same 

 effect upon this external 

 canal as a superior canal 

 running directly from ear to ear 



(Compton-Johnson Co.) 



The Sixth Sense, the Sense of Balance, Lies in the Labyrinth of the Internal Ear 

 The internal ear or labyrinth consists of a bony and a membranous part, the latter contained in the former. The 

 bony labyrinth is composed of the vestibule, the semi-circular canals and the cochlea. These three canals constitute 

 what is known as the static labyrinth upon which we depend for our sense of balance. The bony canals contain the 

 membranous canal, and the membranous canal, in turn, contains the endolymph, which is a fluid that fills the mem- 

 branous canal. The flowing of the endolymph in the semicircular canals is absolutely essential to man's normal station 

 in space with eyes closed or in any situation in which he cannot judge his position by sight. Without a perfect 

 labyrinth, a man could not fly safely for the simple reason that he would have no sense of balance 



