WATER SUPPLY FOR COUNTRY HOME 



479 



water in the tank, forcing it into the pipes. Special provision 

 must be made to pump more air into the tank occasionally. 

 If this is not done the tank will in a short time become " water- 



FIG. 293. Pneumatic tank system. 



logged," that is, all of the air will be removed from the tank 

 by the water which passes through it. How this may be so is 

 more clearly seen after performing the following exercise. 



