TJie Rate of Explosions in Gases. 



137 



to be altered ; the addition of hydrogen increasing the 

 velocity, the addition of oxygen diminishing it. The addi- 

 tion of an inert gas nitrogen, incapable of taking part in the 

 chemical change, produced the same effect as the addition 

 of oxygen — one of the reacting substances — only the retard- 

 ing effect of nitrogen was less marked than that of an 

 equal volume of oxygen. The retardation of the explosion- 

 wave caused by the addition of an inert gas to electrolytic gas 

 evidently, therefore, depends upon the volume and the 

 density of the gas added. In the following table the retard- 

 ing effect of oxygen on the explosion of electrolytic gas, is 

 compared with that of nitrogen : — 



Table VI. 



Rate of Explosion of Electrolytic Gas with Excess of Oxygen 

 and Nitrogen. 



I think it a fair inference from these facts to conclude, 

 when the addition of a gas to an explosive mixture retards 

 the rate of explosion by an amount which depends upon its 

 volume and density, that such added gas is inert as far as 

 the propagation of the wave is concerned, and that any 

 change which it may undergo takes place after the wavQ- 

 front has passed by — in other words, is a secondary change. 



This principle has been applied to determine whether, 

 in the combustion of gaseous carbon, the oxidation to 

 carbonic acid is effected in one or two stages — an important 



