206 MUNROE— EXPLOSIONS OF PETROLEUM VAPOR. [April 22, 



applied to the upper end of the tube (called the mouth) to ignite 

 the vapors and it was then noted if the flame traveled completely 

 through the tube and issued from the bottom end or if it traveled 

 but part way through and became extinguished. In every experi- 

 ment there was some liquid naphtha as well as naphtha vapors 

 throughout the tube at the moment when the flame was applied. 

 Experiments were made in glass and steel tubes varying in diam- 

 eter from .4 inch to 4 inches. The results are presented in the 

 following table. When the flame traveled completely through the 

 tube and issued from the bottom end the result is marked '" posi- 

 tive." When the flame traveled but part way down the tube and 

 became extinguished the result is marked " negative." 



It appears then that where the length of the tube is 63.44 times 

 its diameter or above this the flame does not travel through. 



