346 



Common Science 



FIG. 181. The most powerful explosions on earth occur in connection with 

 volcanic activity. The photograph shows Mt. Lassen, California, the only 

 active volcano in the United States. 



out of its way. The bullet gets such a push through 

 the exploding of the gunpowder that it may fly to a 

 mark and pierce it. 



There is a slight explosion even when you shoot an 

 air gun. First you compress some air in the upper part 

 of the barrel of the air gun ; then you suddenly release 

 it. The only thing in the way of the expanding air is 

 the bullet ; so the air pushes this out in front of it. 



