It EXPIRATION AND THE VOICE. 



131 



2. If you watch the breathing, you will see two regular 

 movements. First, the chest and abdomen seem to swell ; 

 and then, in a moment, they fall back to their former 

 size. This is repeated with every breath. The chest does 

 enlarge; and, as it enlarges, the air rushes in, to fill the 

 extra space. As it grows smaller, the same amount of air 

 that entered is squeezed out again. 



Why does the air rush in, when the spa.ce is made 

 larger? Because air is like 

 water : it is pressing in every 

 direction. If you put water 

 in a tub with a pipe opening 

 out of it, it will force itself 

 into the pipe. If you put 

 a bottle under water, wdth 

 the mouth up, the water will 

 push in, and fill it. We are 

 in the air as the bottle is in 

 the water. If the bottle is 

 made of rubber, the water will 

 flow out when we squeeze it, 

 and will flow in again when 

 it expands. The chest may 

 be likened to such a rubber 

 bottle. 



The chest is like a bellows, with one exception : in a 

 bellows, the air enters by one opening, and goes out of 

 another ; in the chest, air enters and goes out by the same 

 opening. 



3. How is the chest made larger ? In two ways, 

 l. By the descent oil the diaphragm. 



s. By the raising of the ribs and breast-bone. 



Fig. 51. 

 THE CHEST. 



