714 



Popular Science Monthly 



no latent tendency to turn up or down, in 

 or out. The test is important. If there 

 were any such latent tendency, it would 

 manifest itself under 

 great strain ; the 

 aviator would see 

 double and thus en- 

 danger his life. 



And now the ear, 

 nose and throat are 

 examined. The 

 hearing must be per- 

 fect; there must be 

 neither diseased ton- 

 sils nor adenoids ; 

 both sides of the 

 nose must be free, 

 which means that 

 there must be noth- 

 ing present to pre- 

 vent the automatic 

 equalization of air 

 pressure through the 

 Eustachian tubes 

 (the little tubes lead- 

 ing into the middle 

 ear). A military 

 aviator is subjected 

 to a wide range of 

 variation in temper- 

 ature and atmos- 

 pheric pressure. If his nose and throat are 

 not normally ventilated these rapid changes 

 might produce dizziness, vertigo and 

 nausea. He might not be able to control 

 his machine, with the result that he would 

 wreck it and lose his life. 



Your Sense of Balance Is in Your Ears 



We have been taught that we have five 

 senses — sight, hearing, touch, taste and 

 smell. A sixth should be added — that of 

 equilibrium. It is as much a separate 

 sense as touch or sight, and that it is en- 

 titled to consideration as such, the develop- 

 ment of aviation is fast driving home. 

 Balance, or equilibrium, is maintained 

 through the eyes, the skin, the joints and 

 muscles, and, much as it may surprise you, 

 the ears. Just as the end organ of sight 

 is in the eye and the end organ of feeling 

 in the fingers, so the end organ of equilib- 

 rium is to be found in the ears. 



As the accompanying diagram shows, the 

 inner ear is made up of two parts — a 

 cochlea, which contains the end organ of 

 hearing, and the labyrinth, which contains 

 the end organ of balance. In other words, 

 the labyrinth of the ear is the human 

 stabilizer. Nevertheless, from the time 



How Long Did It Take Him to Recover? 



After having been revolved with eyes closed in the 

 chair, the applicant is told to look at a distant object. 

 There will be a rhythmic to and fro movement of the 

 eyes. It lasts as long as the fluid within a particu- 

 lar canal in the ear continues to flow artificially 



that man first discovered the possibilities 

 of travel over the waters and hoisted his 

 first sail over a log, down to the time when 

 he navigated great 

 ocean liners, this 

 little organ of bal- 

 ance has been the 

 one thing that has 

 made the sailing of 

 the seas unpleasant. 

 Not the stomach or 

 liver, but the lab- 

 yrinth is the cause 

 of seasickness. Is it 

 not singular that the 

 organ which upsets 

 us on the ocean sta- 

 bilizes us in the air ? 

 Were it not for the 

 constant intelligence 

 flashed by the lab- 

 yrinth to the brain, 

 the aviator might 

 actually find him- 

 self soaring upside 

 down! His move- 

 ments in the air up 

 and down, right and 

 left, in and out, are 

 constantly regis- 

 tered by this won- 

 of mechanism within 



derful little piece 



The Test for Pass-Pointing 



The applicant extends his right arm and touches the 

 examiner's hand. Then he raises his arm vertically 

 and is told to bring his finger back and touch the ex- 

 aminer's hand again. Another picture shows the result 



