The Rate of Explosions iii Gases. 



157 



\elocity of the sound-wave (2) calculated by my formula 

 is 1,805 or 1,830, according as the lower or higher heat of 

 combination is taken. The rate of the explosion thus falls 

 appreciably below the calculated velocit}- of the sound- 

 wave. 



On diluting the electrolytic gas with hydrogen the rate 

 of explosion was found to increase, and to approximate to 

 the calculated velocity of the sound-wave. While the 

 addition of diluent hydrogen to the electrolytic gas makes 

 little difference in the calculated rates, the observed 

 velocities of explosion increased appreciably. On the 

 assumption that the heat of combination of hydrogen and 

 chlorine is 22,630 calories, the calculated and observed 

 velocities are as follows : — 



Table XXII. 



Rate of Explosion of Hydrogen and Chlorine with addition 

 of Hydrogen. 



These experiments show that in the explosion of 

 hydrogen and chlorine as in the explosion of hydrogen and 

 oxygen, in equivalent proportions, the rate falls below the 

 calculated velocity of the sound-wave, but on diluting the 

 gases the calculated and observed velocities come together. 

 This divergence at the highest temperature may be 

 explained either by the dissociation of the hydrochloric 

 acid or by a rise in its specific heat. As I have shown, we 

 have direct evidence of sovie dissociation. On the other 



