CHILDHOOD EXPERIENCE 



the head was submerged but one foot beneath the surface the lungs seemed 

 to collapse, air was expelled through the hose, and inhalation was a feat of 

 utmost muscular exertion. Then too, even if this feat of breathing could 

 be accomplished, the hose would always contain used air. Only a few feet 

 of hose would contain all of the air exhaled, so that no fresh air would be 

 admitted. We tried holding the hose in one side of the mouth, inhaling 

 only through it and exhaling from the other side, using the tongue as a 

 check-valve. This was too complicated, and after gulping water a few 

 times we abandoned the experiment. 



A few rough figures will show why air at atmospheric pressure cannot 

 be drawn from the surface by a person under water. A cubic foot of water 

 weighs sixty-two pounds. An area one foot wide encircling a man's chest 

 contains approximately three square feet. If he is submerged one foot, he 

 is subjected to a pressure 3x62 pounds, or 1 86 pounds distributed around 

 his chest, not to mention an equal or greater pressure around his abdomen, 

 forcing all of the organs in that region upwards against the -lungs. If our 

 friend descends into the water to a depth of thirty feet, which gives no 

 discomfort to a properly equipped amateur diver, the pressure around the 

 chest is increased to 3x30x62 pounds, or 5580 pounds, and the ab- 

 dominal pressure in like proportion. 



We boys were familiar with the elements of physics and knew some- 

 thing from hearsay and books about submarine diving as used for construc- 

 tion and salvage; consequently, our next experiment was to make a con- 

 traption whereby air at the same pressure as that of the water could be 

 inhaled and exhaled. A large iron bucket was procured and inverted, and 

 sufficient scrap iron was tied to the bale to sink it in spite of the air im- 

 prisoned within. A short rubber tube was equipped with a float at one 

 end so that it would hold that end above the surface of the water. We took 

 our apparatus to the swimming hole and let the bucket down into the 

 water. Then I, with the rubber tube in my mouth, let the other end float 



