fcocal TOnDs, 109 



funnel hangs low enough and the gyratory 

 energy is sufficiently great. There is a great 

 pressure on the water outside of the funnel 

 and almost a perfect vacuum inside. This 

 latter fact contributes largely to the de- 

 structive power of the tornado. When a fun- 

 nel is central over a building a sudden vacuum 

 is created outside of it and it bursts outwardly 

 from the internal air pressure. 



