THE ATMOSPHERE 



mid-stream from bedrock upward, and that he can carry 

 on warfare beneath the 

 waves of the ocean, seems 

 marvelous. These achieve- 

 ments rank with man's 

 mastery of the atmosphere 

 in which he makes the air 

 a highway for travel and 

 for sport, and a place for 

 carrying on warfare. But 

 at all times and everywhere 

 man must be provided 

 with an abundance of air 

 to breathe, or death from 

 lack of oxygen speedily 

 follows. 



By use of powerful com- 

 pression pumps large vol- 

 umes of air may be made 

 to occupy little space 

 within a submarine. By 

 its withdrawal from one 

 side of an air- tight movable 

 partition water can push 

 its way into the boat, 

 causing it to sink. By 

 allowing the compressed 

 air to expand this water 

 is again driven out, and 

 the boat is so lightened 

 that it will come to the 

 surface. By use of electric 

 motors, the boat is rapidly 

 propelled through the water beneath the surface, and its 



