GASES WHICH DO NOT IGNITE IN NITKIC OXIDE. 63 



sufficient to burn the carbonic oxide, but all round the path of 

 the spark the temperature fell rapidly to a point at which it 

 could still decompose the nitric oxide, without igniting the 

 carbonic oxide. 



The oxygen formed at the expense of the former compound 

 thus produced nitric peroxide gas with the surplus. 



8. The contrast will be remarked between this experiment 

 and the sudden combustion of carbonic oxide produced by 

 mercury fulminate detonating in nitric oxide (see further on). 

 The fact is that the latter agent sets free at once all the oxygen 

 of the oxide without passing through the state of nitric per- 

 oxide. 



9. Let us examine more closely the list of gases and other 

 bodies capable of burning direct at the expense of the nitric 

 oxide by simple inflammation, or electric sparks, and seek the 

 causes of the difference which exists between the reaction of 

 these bodies and of those which do not burn immediately. 



The following do not ignite : 



Nitric oxide and hydrogen in equal volumes, 



Nitric oxide mixed in the same way with carbonic oxide, 



NO + CO. 



Nitric oxide mixed with marsh gas, 

 4NO + CH 4 . 

 Nitric oxide mixed with methyl chloride, 



3NO + (CH 3 C1). 



And even nitric oxide mixed with methylic ether, 

 6NO + (CH 3 ) 2 0. 



The combination of these mixtures does not take place by 

 contact with a small flame, nor under the influence of electric 

 sparks. 



Sulphur also, when simply ignited, is extinguished in nitric 

 oxide. 



This absence of combustion is especially remarkable with 

 methylic ether, which takes the same quantity of oxygen and 

 disengages nearly the same quantity of heat as ethylene, a gas 

 which burns, on the contrary, at the expense of the nitric oxide. 

 The two mixtures occupy, moreover, the same volume. 



10. On the other hand, the contact of a lighted match ignites 

 the following mixtures when formed according to equivalent 

 ratios of volume : 



Nitric oxide mixed with cyanogen, 



2NO + CN. 

 Nitric oxide mixed with acetylene, 



5NO + C 2 H 2 . 

 Nitric oxide mixed with ethylene, 



6NO + C 2 H 4 . 



