6 Jones and Bower, Explosion Wave Pressures. 



to make sure that one explosion did not tend to diminish 

 its strength, and it was found that if a tube stood an 

 explosion once it would remain intact after any number 

 of explosions, and yet would be shattered to fragments by 

 the pressure produced by impact of two explosion waves. 



The samples of tube which were hydraulically tested 

 gave the following results for breaking pressures : — 



1. Tubes which broke one way — 



r84olbs. per sq. in. ) , , 



1o ^,u >Mean 8681bs. = 58 atmos. 



t8961bs. „ j 



2. Tubes which stood one way, but broke with two 

 waves meeting — 



looolbs. per sq. in.\ 



I232lbs. „ [Mean iii7lbs. = 75 atmos. 



.ii2olbs. „ J 



3. Tube which stood both ways — 



I344lbs. = 90 atmos. 

 Hence we have the increase of pressure on collision of 

 two explosion waves clearly demonstrated. 



Comparison of these numbers with those of the earlier 

 paper will shew a considerable difference. 



As previously stated, the higher numbers obtained by 

 Dixon and Cain are possibly due to the fact that their 

 tubes were fractured, not by the explosion wave, but by 

 the greater pressure always evident at the point of redeter- 

 mination of the wave after a partial stoppage. We are 

 now conducting experiments with other mixtures of gases. 



The phenomenon of the collision of two true explosion 

 waves is shown in 7%-. /(.. 



The photograph shews that the junctions in the appa- 

 ratus produced no disturbing effect on the explosion wave. 



Two rebound waves start from the point of collision 

 in opposite directions along the tube. These are sound 

 waves, made luminous by passing through the still heated 

 gases. A comparison of this photograph, where the true 



