Method of Measuring Exjilosion Pressures, 481 



found. Thus Table I. gives a time-pressure history of the 

 explosion. 



Table I. 



Tii 



ne xlO 3 second. 



Pressure 



3 (Displacement 



in cms.) 





0-3 









•90 







0-8 









•61 







1-7 









•46 







2-9 









•38 







53 









•33 







7-0 









•30 







12-0 









•24 







15-3 









•21 



" 





17-6 









•18 







23-8 









•16 







25-1 









•15 







30-4 









•13 





Figure 6 shows three time-pressure curves obtained in this 

 manner. They are of interest as showing the great differ- 

 ence in behaviour of the explosion in the three cases. When 



•015 -02 -025 

 Time , Se conds. 



■ Time-Pressure Curve for Explosion of Mixture of H 2 0, Gas, and Air. 

 Volume of Mixture = 705 c.c. 



Initial Pressure == 70 cm. of Ilg. 



One cm. displacement = 220 Ib./sq. inch. 



Curve I. — Volume of Gas = 705 c.c. 

 Curve II.— „ ,, =400 „ 



Curve III.— „ ,. =300 ., 



Air = none. 

 .. =305 c.c, 

 „ =465 .. 



